Enercon (India) Limited vs Alloys Wobben

D.P.S. Parmar, Technical Member

This application u/s. 64 read with section 117D of the Patents Act, 1970 is filed for revocation of patent No. 200249 (herein referred to as 249)

granted to Aloys Wobben for invention ""A wind power installation and process for the operation of the same "". This application for revocation was

filed by Enercon India Limited. From the records in Intellectual Property Appellate Board (IPAB), it was observed that this matter was heard by the

earlier Board on 1.11.2010 and orders were reserved. Since the Hon'ble Technical Member Shri Chandrasekaran retired on 02.12.2010, decision was

not issued. So this case was listed to be heard again. In the meantime, the matter was transferred to the new counsel for the respondents. On

completion of all the formalities, the matter was heard on 16.04.201 to 17.04.2013. MP/22/2013 for stay was dismissed as not pressed.

Mr. R. Parthasarathy Senior Advocate appeared for the applicant and Mr. Praveen Anand senior Advocate represented the respondent. Both the

counsel, besides arguing the matter at length, has also filed their written submissions on the preliminary issue as well as on merits.

Preliminary objections by respondent locus standi

Mr. Praveen Anand senior Advocate for the respondent raised the issue of locus standi and licensee estoppel. So far as the preliminary objection

taken by the respondent questioning the locus-standi of the applicant to move the revocation application as a ""person interested"" under S. 64 of the

Patents Act, 1970 is concerned this question has already been decided against the respondent by this Board in the cases between the same parties in

ORA/43/2009/PT/CH and others by order dated 16.11.2010. We will call it the First Batch. This application forms part of the Second Batch which

had to be heard again. The Board was pleased to hold that the applicant has ""a known and general interest"" together with ""commercial interest"" by the

grant of the patent in question and therefore, they are definitely ""persons interested"". All the revocation applications in the First Batch were allowed

and the patents were revoked. The respondent has challenged these orders in the Hon'ble Madras High Court and the writ petitions are pending. In

ORA/6/2009/PT/CH this Board has already decided that the applicant is a 'person interested'. (Para 10)

Here, the applicant as an interested person has been enjoying the benefit of the technical know-how of the respondent. There is no denial that the

applicant has established an industry on the basis of this. If the licence has been removed or revoked, then, the applicant in the course of business will

be prevented from selling the machinery, and the respondent is already suing for infringement. If the applicant succeeds in demolishing the patent in

accordance with law, then the infringement suit must fail and the applicant's commercial interest will be secured. Therefore, the applicant herein

passes the test of Ajay Industrial Corporation case. In any event, the definition of 'person interested' is not restrictive, but inclusive. Therefore, unless

it is shown that the challenge to the patent is frivolous and with a view to extract more money from the patent holder, we are bound to examine the

patentability of the invention. We are not sure how far the conduct of the party will weigh with us while deciding a revocation petition. Though S. 64

used the words, 'may be revoked', if the revoking applicant proves obviousness under section 64(1)(f) or that the invention does not involve any

inventive step, the IPAB cannot say that it is true that the invention is obvious but since S. 64 gives us the discretion, we will not revoke the patent.

That will set the Patent Law on its head. Therefore, the fact that the applicant has not behaved in an unexceptional fashion towards the respondent

will not weigh with us if the applicant proves that the invention is not patentable, on the ground that either it is not an invention under S. 3 or since the

invention is anticipated or that it does not satisfy the definition of S. 2(1)(j) and 2(1)(ja) or if the grounds under S. 64 are made out. The patent

monopoly is not given lightly. If the applicant has not paid the royalty or has displayed bad faith, the respondent can sue the applicant for compensation

elsewhere. On that ground an inventor cannot have an unworthy patent protected. We are therefore satisfied that the applicant has the locus standi to

file this revocation application. We are not inclined to differ from the views of the earlier Bench in his regard.

We are adopting this decision as the facts and circumstances of this case are same.

Licensee estoppel

The issue of licensee estoppel was also raised in ORA/6/2009/PT/CH. We are not dealing with this issue here as we have already dealt with it in

ORA/6/2009/PT/CH and we adopt the same in this case. (para 16)

16....So we have the Act which says that the conditions which restrict the right of a licensee from challenging the patent are illegal and we have the

opinion of the U.S. Supreme Court explaining why a licensee is entitled to invalidate the patent. This restriction imposed by S. 140, is another indicator

of the public interest angle in patent law. While the law shall protect the rights of the property owner, it will not restrict the rights of the interested

person to challenge the grant, so that unworthy patents are restored to the public domain. Because of the costs of the litigation and the very special

nuances of the technology, it may very well be that the licensee alone is capable of challenging the patent. He has the funds and the knowledge to

launch the attack on the subject matter of the invention. This is why the U.S. Supreme Court held that it would be inequitable to restrict him from

attacking the patent by any condition in the contract. The Parliament has specifically introduced this provision in our Patents Act which is a special

enactment as far as patents are concerned and hence it will prevail over the general rules relating to contract. Therefore no licensee can be estopped

from challenging the patent. This objection is rejected.

Miscellaneous Petition No. 47/2011 for amendment

The learned counsel for the respondent filed a Miscellaneous Petition No. 47/2011 for amendment of the claims. The learned senior counsel Shri R.

Parthasarathy counsel for the petitioner objected to the amendment in the claims.

The learned counsel submitted that in this matter, the pleadings were complete in March 2010 and hence the proposal to amend the

specification/claims at this late stage, in October 2011, deserves to be rejected. The Petitioner served an M.P. for amendment almost 22 months after

the revocation application was filed. In addition no amendments were proposed in the counter statement. The revocation petition was heard by earlier

Bench on 01.11.2010 and order was reserved.

The learned counsel submitted that it is also pertinent to note that the Notice for rehearing of all the matters was given in February, 2011 and yet

the amendments are being proposed after a delay of 8 months from the date of notice of hearing. Thus, this delay disentitles the patentee from the

exercise of the discretion by the IPAB. The matters were listed on 8th August, 2011 on which date, the Hon'ble IPAB was pleased to fix the date of

next hearing as 21.11.2011. Even as per the admission of the Patentee in the present petition, despite the counsel for the patentee receiving the

documents in May, 2011, amendments are being proposed in October, 2011, clearly to delay the proceedings and to have the matters adjourned on

21.11.2011. The learned senior counsel submitted that it may be seen from the above dates and events that there is an inordinate delay in making the

present amendment to the specification/claims.

The learned counsel submitted that Section 58 of the Patents Act, 1970 empowers the Appellate Board to allow the Patentee to amend the

complete specification in any proceedings before the Board. Section 58(1) is discretionary and the discretion may not be exercised in case where the

patentee has delayed the moving of application for amending the specification claims.

The learned counsel submitted that the reason given in the petition for amendment is that the new counsel got the documents only in February 2011

and hence became aware of the subject matter only then and that he came to the conclusion that the specification needed amendment when their

team visited Germany. Such a contention cannot be a reason to allow amendment. The patentee was always aware of his patent and change of

counsel cannot be a reason for moving the amendment at this late stage. It appears to be a ploy to delay the hearing.

The learned counsel submitted that in fact, the amendments brought forth in the present Petition are not such that would have required the alleged

plant visit. It is an old tactic of the Petitioner who has been constantly trying to stall the proceedings and cause delay even when he was represented

by the old counsel. In view of the above, it is not open for the Petitioner to move for amendment of specification at this stage.

Without prejudice to the above submission, In any case, the learned counsel submitted that the amendments do not satisfy the requirements of

Section 58 and 59 of the Act and that the amended claims are also invalid under Section 64 of the Act.

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AMENDMENT SOUGHT:

The Amendment petition states that the amendments in claims 1,2,3 and 19, are sought to bring out clarity and further explain the inventive step

and novelty.

Mr. Anand submitted that petition for amendment of the claims had been filed because of new perspectives and insight gained as a result of the

understanding of the technologies. The respondent has carefully contended that the amendment should not be considered as an admission of the

deficiency in the claims. He submitted that these amendments are within the provisions of section 59 of the Indian Patent Act and are made by way of

explanation and correction as illustrated below: -

a. Amended Claim 1 is narrower in scope than original claim and has been amended to bring out clarity and further explain the inventive step and

novelty of the present invention.

b. Without limitation, reference numerals have been introduced in the independent claim 1 in order to enhance its intelligibility. The inclusion of

reference numerals in the independent claim 1 is not intended to limit the scope of the claim in any manner what so ever.

c. Dependent claims 2 & 19 have been amended to replace ""measurement means (38, 40, 44)"" with ""measuring means (38, 40, 44)"" in order to make

these claims consistent with other claims and the specification and to further clarify the present invention.

d. Dependent claim 3 has been amended to correct the clerical errors.

e. Original dependent claims 2 to 21, independent claim 22 and omnibus claims 23 & 24 have been retained in their original form.

We also sought the opinion of the Controller of Patents relating to the amendment sought by the patentee vide IPAB Order Sheet dated

21/01/2013.

On 2nd May 2013, the information of the Assistant Controller of Patents and Designs, Chennai was received wherein it was stated that

Claims 1, 2, 3 and 9 have been amended.

Claims 2 & 9 are amended by replacing the term ""measurement means"" with ""measuring means"". This amendment is found to be carried out to

incorporate the term as used in other claims. This is clear from the reference numerals indicated for 'measuring means' in other claims. Hence, this

amendment is in accordance with sec 59(1) of the Patents Act, 1970.

Claim 3 is amended for grammatical error by replacing the word 'is' with 'are' and the reference numeral 40 indicating the measuring means is deleted.

The grammatical error correction is appropriate as there are different measuring means 38, 40, 44 for measuring different parameters like mechanical

loading and wind speed. The deleting of numeral 40 is to make the claim in line with description. Hence, these amendments are in accordance with

sec 59(1) of the Patents Act, 1970.

Claim 1 has undergone many corrections.

Correction 1: The word 'comprises' is replaced with 'comprising'. The term 'blade angle position' is replaced with 'blade angle setting'. These

corrections do not change the definition or scope of the claims already on record.

Correction 2: In line 3 of original claim 1, the term 'a rotor blade' is redrafted as 'each rotor blade'. This correction when read in context seems to alter

the functional scope of the adjusting device (34, 36). Originally, an adjusting device in claim 1 is defined by its function as a device for individually

adjusting a rotor blade to a desired blade setting angle which gives an understanding that the adjusting device adjusts only one of the rotor blades alone

to set its angle. But, in the present amendment, by introducing the word 'each', it gives an understanding that the adjusting device adjusts everyone of

the rotor blades individually to set its angle. This widens the scope of the original claim 1 and hence, this amendment in claim 1 is not in accordance

with sec 59(1).

Correction 3: In line 9 of original claim 1, the phrase ""which suitably adjust of other rotor blades"" is redrafted in line 7 of amended claim 1 as ""the

adjusting device..........of the other rotor blade or the other rotor blades"". As per the original claim 1, the control means makes the adjusting device to

adjust the rotor blade angle to a desired setting asynchronously from the blade angles of all other rotor blades. This gives an understanding that the

rotor blade under consideration as well as other rotor blades will have different blade angles. So, whenever the blade angle of a rotor blade is set, it

will be asynchronous with the angles of other rotor blades. None of the two blade angles will be set as same. This amendment introduces the phrase

the other rotor blade"" as an option in the control and functionality of the adjusting device. With this amendment, it is understood that the control device

controls the adjusting device in such a manner that a rotor blade under consideration is adjusted to a desired blade angle setting asynchronously from

the blade angles of any single other rotor blade or the blade angle setting of all other rotor blades. This gives an understanding that while the blade

angle of a rotor blade under consideration is set it may have asynchronous angle with other single rotor blade and have synchronous angle with all

other rotor blades or may have asynchronous angle with all other rotor blades. The introduction of this option widens the scope of the original claim

and is not in accordance with sec 59(1).

Correction 4: In line 4 of the original claim 1, the phrase ""said rotor hub......... of the hub or a rotor blade"" has been redrafted in line 12 as ""with

measuring means (40) mechanical loading of the hub"". As per line 4 of original claim 1, the measurement means (38, 40, 44) is understood to be

provided in rotor hub only for ascertaining at least one of the instantaneous mechanical loading of the hub or a rotor blade whereas in line 12 of

amended claim 1, the position of the measuring means (40) alone is specified to be on the rotor hub. This restriction introduced in the claim is for the

purpose of making the claim to be in line with the description. Hence, this amendment is in accordance with the provisions of sec 59(1).

However, in view of corrections 2 & 3 to claim 1, the amended claim 1 is not allowed as it do not satisfy the requirements of sec 59(1) of the Patents

Act, 1970.

The counsel for the respondent in the written note relating to the opinion of the controller submitted that the Respondent disagrees with the

Learned Controller that 'Correction 2' and 'Correction 3' are not in accordance with section 59(1) of the Indian Patents Act, 1970. In this regard, the

Respondent submits as follows:

CORRECTION 2:

The phrase 'rotor blade' is amended to 'rotor blade' in order to clarify that an adjusting device is provided for the individual adjustment of each

respective rotor blade. This can be seen in Figure 1 of IN 200249 on page 38 of the revocation petition and its description in third paragraph on page

29 of the revocation petition, which states that ""An adjusting motor 34 is mounted on the flange connection 32 and adjusts the rotor blade 16 by way of

an adjusting transmission 36"". Therefore, it is clear that one adjusting device is provided at the root of each rotor blade to adjust the respective rotor

blade. It clarifies for example for a wind power installation having 3 rotor blades, that there are 3 adjusting devices, one per rotor blade. In other

words, an (one) adjusting device is provided for each rotor blade, but not one for all rotor blades.

Therefore, this amendment in claim 1 is merely clarificatory in nature and does not broaden the scope of the claim. Nevertheless, as submitted

during the hearing, the Respondent has based his arguments on the originally granted claims. It is further submitted that the Respondent is willing to

revert to the originally worded claim 1 in case the Hon'ble Board decides that the present amendment broadens the scope of claim 1.

CORRECTION 3:

It is clarified in the amendment proposed in claim 1 that the blade angle setting of a rotor blade can be adjusted asynchronously from the blade angle

setting of the (QM) rotor blade (in case of a wind J2ower installation having two rotor blades), or the blade angle setting can be adjusted

asynchronously from the blade angle setting of the other (more than one) rotor blades (in case of a wind power installation having more than two rotor

blades) since claim 1 relates to a wind power installation comprising ""at least two"" rotor blades.

To explain this for an example of a wind power installation having 3 rotor blades, adjusting the blade angle of one rotor blade asynchronously from

the blade angle setting of the other two rotor blades does not imply, that the other two rotor blades have the same blade angle setting.

Therefore, this amendment in claim I is also merely clarificatory in nature and does not broaden the scope of the claim. Nevertheless as submitted

above, the Respondent is willing to revert to the originally worded claim 1 in case the Hon'ble Board decides that the present amendment broadens the

scope of claim 1.

The counsel for the applicant submitted that the applicant agrees with all the comments and recommendation of the learned Controller except

finding of the Controller in regard to correction 4.

The counsel for the applicant submitted that the learned Controller has observed that the claim 1, 2, 3 and 9 have been amended. With regard to

proposed claim 1, the Controller has recorded that the amended claim 1 falls foul of Section 59 inasmuch as the amended claim does not fall wholly

within the scope of any other granted method claim. The Applicant agrees with the opinion because the introduction of word ""each"" gives an

understanding that the adjusting device adjusts every one of the rotor blades individually to set its angle in comparison to an understanding that the

adjusting device adjusts only one of the rotor blades.

In view of the above, and the opinion of learned the learned counsel contended that the proposed amendments be rejected and consequently all the

claims of the impugned patent 200249 be revoked.

We find this amendment is proposed without prejudice to the original claims. The reasons for delay submitted by the respondent that because of

new perspectives and insight gained as a result of the understanding of the technologies and not to cure any deficiency in claims. We find lot of

discrepancies in the claims for instance The said measurement means as claimed in claims 1 and 2 are measurement means (38,40,44) but in claims

3,4,6-14 they are given as 'measuring means (38,40,44)' and claim 13 states 'measuring means (38,40,44) for measuring the load have strain gauges

(38,40). In claim 17 it is stated that ""input means (38), which is connected to the controller 8 for in putting the desired position of the rotor blades or

blades for a given instantaneous loading.

In May and Baker Ltd.'s patent (1948) 65 R.P.C. 255, the Court had to consider whether the amendment of a chemo-therapeutic patent must be

allowed. The Court held that if the claims made by the unamended specification are covetous that ""should in itself be a ground for refusing the

amendment as a matter of discretion."" In ORA/14/2009/PT/MUM VRC Continental Ltd. Vs Uniroyal And Others dated 24.8.2012, this Board had

relied on Matbro Ltd. v. Machingan (GB) Ltd. [ (1973) RPC 823] in relation to belated amendments and held that,

a clear distinction between instances where a patentee knows of prior art which he genuinely, and quite properly in the circumstances, thinks is

irrelevant, and other instances where, though he learns of or has been warned of objections which are available against his patent as a result of prior

art, yet he takes no steps to put his specification right by way of amendment, or still worse, knowingly persists in retaining it in the unamended and

suspect form. In the latter cases delay is culpable because potential defendants and the general public are entitled to plan their activities on the

assumption that the patentee, though warned, has decided not to amend. If the patentee, by his conduct, lulls the public into a false sense of security he

cannot thereafter be allowed to change his mind and ask for amendment, or at any rate without adequate protection being granted to the public.

and refused to allow the amendments. We find this applicable to this case also and refuse to allow the belated amendments. We have found the

discrepancies in the claims and now the request for amendment in deletion of 'or Rotor blade' among other corrections some of which controller found

beyond the scope of original claim dissuade us from accepting the request of the respondent for amendment at this stage. We decided to proceed with

the matter based on the patent specification on record.

Grounds for revocation

The counsel for the applicant submitted he is pressing on ground that the patent is anticipated, and it is obvious.

The counsel for the applicant submitted that the Patentee has admitted that the following,

a) Wind power installations with at least one rotor blade;

b) an adjusting device for individual adjusting of at least one rotor blade;

c) generator connected to the rotor;

d) measuring means;

e) controlling or regulating device (it is implicit that measuring and adjusting would happen only with a control means)

The counsel for the applicant submitted that any control system necessarily involves (i) a Standard for a parameter, (ii) an actual measurement of

the parameter value, (iii) comparison to determine the deviation of the actual from the Standard and (iv) corrective action for correcting the deviation.

Thus, the existence of the adjusting device in the prior art pre-supposes an actual measurement (measuring means), determination of deviation (control

or regulating device) and corrective action (adjusting device). The only issue is the position of the measurement device. Thus, the only inventive

feature of claim I is the position of the measuring means on the rotor hub. According to the counsel this measuring means may be strain gauges to

measure the mechanical loading as admitted in the patent specification (Page 29, 30).

Anticipation

According to the counsel for applicant IN '247 is anticipated by GB 2,067247 (22.07.1981) for a device for determining the wind energy in order to

control wind generator. The counsel for respondent submitted that GB'247 was considered during prosecution of corresponding EP application and

patent EP 0998634 was granted. We pause here to note that claim 1 of the EP '634 is not same as the impugned patent.

The counsel for the applicant submitted that claim 1 comprises of following elements

Wind power installation comprises a rotor with a rotor hub with at least two rotor blades which are rotatable about the longitudinal axis; an adjusting

device for individually adjusting a rotor blade to a desired blade setting angle,' a generator which is operatively connected to the rotor; said rotor hub is

provided with measurement means for ascertaining at least one of the instantaneous mechanical loading of the hub or a rotor blade, control means for

ascertaining a blade angle position which is wanted for the reduction in the instantaneous loading using a variation in the instantaneous blade angle

position of at least one rotor blade and which suitably adjust the rotor blade to the desired blade angle position by the adjusting device asynchronously

from the blade angle position of other rotor blades,' and said adjusting device and said measuring means being connected to the control means.

According to the counsel for applicant claim 1 of the EP '634 is substantially narrow as compared to impugned patent. According to the counsel as

per rule 43(1) of EP convention claimed elements mentioned before 'characterised in that' are admitted as prior art. This characterised portion that

characterised in that the rotor hub is provided with measuring means (40), with which the instantaneous mechanical loading of the hub of the wind

energy plant can be determined."", according to the counsel is the inventive feature. Therefore, the only inventive feature of the claimed impugned

patent is the positioning of the measuring means on the rotor hub. These mechanical loading measuring means may be strain gauge [complete

specification (CS) page 11 line 22]. According to the counsel for respondent the measurements means according to claim 1 primarily serves to

ascertain the instantaneous mechanical loading on the hub or the rotor blade of the wind power installation.

According to the counsel GB'247 discloses a wind power installation having at least one rotor blade having a device for ascertaining the wind

energy (pressure probes) in the rotor plane and this device can be arranged at any place from tip to root of the rotor blade. These pressure probes

(measuring means) measure the mechanical loading on the rotor blades.

The learned counsel submitted that it is well known in the art that pressure probes and strain gauges are the same. To substantiate this, he relied

upon GB 1437433 (Page 64; line 120 to 124) to show that pressure probes and strain gauges are the same.

According to the counsel this prior art also teaches the adjustment of the individual rotor blades (Page 46; line 20). Further, this prior art teaches

that the generator is connected to the rotor. Further, it also teaches that the controller is connected to the adjusting device and measuring means (Page

45; line 115 to 124).

The learned counsel argued that according to the Respondent No. 1, the only difference between the claim 1 of impugned patent and the teaching

of this prior art is that this prior art does not teach that the measuring means is placed on the rotor hub and contended that GB'247 (Exhibit 2) discloses

that there is an anemometer, on the rotor hub, which will calculate the wind speed. The counsel argued that mechanical loading can be deduced from

the wind speed. This argument of the Applicant was supported by the Respondent's expert who states that any instantaneous mechanical load

information would have to be deduced from the measured values of the wind velocity.........(Page 7, lines 26 to 29). Thus, the anemometer described

in GB'247 could be used for measuring mechanical load. Hence there is no difference between the claim 1 of the Impugned Patent and the teachings

of GB'247. Thus, claim 1 is anticipated by GB'247.

According to the counsel given the objective of measuring the mechanical loading of the rotor it is so obvious that a skilled person would arrange

the measuring means only at the location where the loading has to be measured. Thus, the rotor, the rotor hub, the drive train, the stub shaft and the

rotor blade are the obvious choices for measuring the mechanical loading at each of these places. This view is also supported by the fact that while

Claim 1 is for placing the measuring means in the rotor hub, Claim 3 is for providing the measuring means on the rotor blade, claim 6 is for placing it to

measure the mechanical load in a portion of the rotor and claim 10 read with Fig 3 is for the stub shaft. However, since all claims are dependent

directly or indirectly on Claim 1, providing the measuring means on the rotor hub is the alleged inventive concept of the entire patent.

According to the counsel for applicant GB' 247 anticipates impugned patent. The counsel for respondent submitted that GB'247 does not disclose

how the mechanical loading is measured and the position of the measurement device is also not disclosed. The counsel for the applicant argued that

the claim 1 does not state the method by which the mechanical loading is measured. Further this method has not been disclosed in impugned patent

CS. All that has been disclosed was placing of strain gauge in the rotor hub or stub shaft etc.

Respondents reply

The learned counsel for the respondent submitted that the wind power installation as per granted claim 1 of the subject patent comprises the

following elements:

a. a rotor having a rotor hub and at least two rotor blades which are rotatable about their longitudinal axis of the rotor blade;

b. an adjusting device for individually adjusting the angle of the rotor blade to a desired blade setting angle

c. a generator which is operatively connected to the rotor

d. measurement means provided on the rotor hub for ascertaining the instantaneous mechanical loading on the hub or a rotor blade

e. control means for determining a (new) blade angle (with respect to a rotation along the longitudinal axis of the rotor blade) which is required for the

reduction in the instantaneous loading using the variation in the instantaneous blade angle position of at least one rotor blade

f. control means suitably adjusts the rotor blade to the desired blade angle position by the adjusting device asynchronous (independently) from the

blade angles of the other rotor blades

g. the adjusting device and the measuring means are connected to the control means.

According to the counsel the granted claim 1 in element 'd' clearly specifies that the measuring means is located on the rotor hub and the purpose

of the measuring means is to measure the instantaneous mechanical loading on the rotor hub or the rotor blade.

The learned counsel submitted that in order to construe the scope of an invention all elements of a claim should be read in combination. It is not

sufficient to isolate an element of a claim and to compare the same with a prior art in order to access its novelty or inventive step. In other words, it is

not proper to dissect a claim and to search each element independently in the prior art without taking into consideration the context of the invention.

The learned counsel submitted that the applicant argued that according to para 1 on page 24 of the revocation petition, the measuring means for

ascertaining mechanical loading on the rotor hub can be an anemometer. The averments of the applicant are false as the applicant has failed to

interpret the relevant section of the specification. It is submitted that para 1 on page 24 of the revocation petition clearly states that in one preferred

embodiment, the measuring means ascertain wind speed at the rotor blade and for this purpose, the measuring means have an anemometer mounted

on the rotor blade. Therefore, the fact that the specification clearly illustrates that the measuring means an anemometer, a skilled person reading the

specification would clearly understand that the anemometer is only an ""additional"" element of measuring means. He contended that an anemometer

can never measure the mechanical loading. On the contrary, an anemometer can only measure wind speed.

The learned counsel submitted that that even claim 4 of the subject patent recites that the measuring means for measuring the wind speed an

anemometer. This phrase clearly does not mean that the measuring means is an anemometer to measure mechanical loading. The counsel submitted

that the measurement means according to claim 1 of the subject patent primarily serve to measure the instantaneous mechanical loading on the hub or

the rotor blade. This is done by providing strain gauges directly on the rotor hub. The strain gauges can also be provided in the stub shaft or spindle

portion or drive shaft. According to the counsel the additional measurement means i.e. anemometer for measuring wind speed and wind vanes for

measuring afflux angle of the wind may be provided in order to provide additional input values to the control means to establish the optimum blade

angle.

We pause here to see how the measurement means of claim 1 are defined in subsequent claims The said measurement means as claimed in

claims 1 and 2 are measurement means (38,40,44) but in claims 3,4,6-14 they are given as 'measuring means (38,40,44)' and claim 13 states

'measuring means (38,40,44) for measuring the load have strain gauges (38,40). In claim 17 it is stated that ""input means (38), which is connected to

the controller 8 for in putting the desired position of the rotor blades or blades for a given instantaneous loading. There is in fact a visible inconsistence

in defining the measurement means in the claims. The learned counsel for the respondent tried to explain that the 'measuring means (38,40,44)' in

claims are not correctly depicted and proposed to amend the claims and file MP 47/2011. We have dealt with amendment separately.

The counsel for the respondent submitted that '247 was also considered by the European patent office during the prosecution of the corresponding

European patent no. 0998634. A copy of EP 0998634 as granted was enclosed by the Respondent with the counterstatement as Annexure A.

According to the counsel '247 relates to a device for determining the wind energy in order to control wind generators. The purpose of '247 is to

determine wind energy and its objective is to maximize efficiency of the system and to achieve a good control (lines 25 to 28 on page 45 of the

revocation petition). '247 disclose a controller 7 and an adjusting device 8 (refer lines 119 to 121 on page 45 of the revocation petition). According to

the counsel '247, pressure probes 10 are provided near the tip 11 on both sides of the rotor blades (refer lines 125 to 129 on page 45 of the revocation

petition). It discloses that a Robinson's anemometer 16 as shown in Figure 4 and described on in lines 36 to 50 on page 46 of the revocation petition.

The counsel for the respondent submitted the applicant has alleged that the anemometer described in '247 corresponds to the measurement means

as claimed in claim 1 of the subject patent. It is submitted that the measurement means of the present invention measure the instantaneous mechanical

loading on the rotor hub. However, the anemometer as described in '247 does not measure mechanical loading. On the contrary, the anemometer is

capable of measuring only wind speed. In any event, as described in '247, the anemometer 16 only controls the system outside its actual operating

range i.e. when the wind drops or the rotor becomes stationary for example during storm conditions. In the case of a storm, the wind power

installation is switched off and only anemometer is working in that condition for providing the actual wind speed. It is only when the wind speed

measured by the anemometer reaches within the acceptable range, the wind power installation operates and the wind power installation is switched

from anemometer to pressure probes (lines 36 to 50 on page 46 of the revocation petition).The counsel submitted that the anemometer 16 described in

'247 is not provided on the rotor hub. The rotor hub is that part of the rotor to which the rotor blades are attached. On the contrary, the anemometer is

provided outside the rotor hub i.e. on the nacelle, which is a stationary part of the wind power installation.

The learned counsel submitted that as per the disclosure of '247, the rotor reduces the wind speed in its plane to approximately 1/3 (refer lines 37

to 41 on page 45 of the revocation petition). In other words, the wind speed on the right side of the rotor (in the area where anemometer is placed) in

Figure 4 above reduces to one-third of the wind speed on the left side of the rotor in the said figure. Therefore, even the anemometer 16 on the right

side of Figure 4 above will not be able to provide accurate reading of the wind speed, leave alone mechanical loading acting on the rotor.

According to the counsel the applicant alleged that the pressure probes 10 described in '247 correspond to the measurement means as claimed in

claim 1 of the subject patent. Although the Respondent admits that the pressure probes 10 are described in '247, it is denied that these pressure probes

correspond to the measurement means of the present invention. At the outset, it is submitted that the measurement means of the present invention

according to claim 1 of the subject patent is provided on the rotor hub for ascertaining the instantaneous mechanical loading of the hub or a rotor

blade. On the contrary, the pressure probes described in '247 are provided near the tip of the rotor blades i.e. at a distance of 0.7 of the length of the

rotor blades (refer line 127 on page 45 to line 2 on page 46 of the revocation petition). It is submitted that the objective of '247 is met by placing the

pressure probes outside and away from the rotor hub i.e. near the tip of the rotor blade. Therefore, it is submitted that '247 teaches away from the

invention claimed in the subject patent.

The learned counsel submitted that according to '247, the pressure probes are provided on both sides of the rotor blade. From the difference in

pressure ascertained by the pressure probes 10, the initial angle of the wind ""a"" can be deduced. If the setting angle ""(3"", the pressure difference by

the pressure probes and rotary speed of the rotor are known, then wind speed prevailing locally on the rotor blade can be deduced (refer lines 6 to 13

on page 46 of the revocation petition). From the wind speed so deduced and from the values of air pressure, temperature, area of the rotor circle, the

effective wind energy can be calculated in a further calculation process (refer lines 56 to 59 on page 46 of the revocation petition). This is the heart of

the subject matter claimed in '247.

The learned counsel submitted that if the correlation between mechanical loading and wind energy was present, the same should have been

brought out by the Applicant in their evidence. However, the Applicant failed to provide such correlation, which clearly shows that the analysis of the

Applicant is completely based on hindsight. He argued that neither the anemometer nor the pressure probes are suitable to ascertain the instantaneous

mechanical loading of the rotor hub or the rotor blades. While the anemometer measures wind speed and is placed on the nacelle behind the rotor

blades, the pressure probes measure pressure differential at the tip of the blades. Therefore, there is no teaching in '247 of a measurement means

being provided at the rotor hub for ascertaining mechanical loading of the rotor hub or rotor blades.

The learned counsel submitted that the Applicant has made contradictory statements that anemometer is equivalent to the measurement means of

the subject patent and pressure probes are also equivalent to the measurement means of the subject patent. It is submitted that a prudent person

skilled in the art ought to infer that one statement can be true but not the other, which is contrary thereto.

The learned counsel submitted that even the wind direction indicator 6 (Figure 4 of '247 above) cannot be considered as an equivalent to the

measurement means of the subject patent as the wind direction indicator 6 indicates the direction in which the wind is blowing and does not measure

the mechanical loading acting on the rotor hub. In any event, even the wind direction indicator 6 is arranged outside of rotor hub of the wind power

installation as can be seen in Figure 4 of '247.

The learned counsel argued that '247 fails to disclose the control means for ascertaining a blade position required for the reduction in the

instantaneous loading of the rotor hub or the rotor blades as '247 fails to disclose a way to determine the mechanical loading of the hub or the rotor

blade. He applied 'All Element Test' for proving anticipation as given below:

and contented that the law on anticipation is not satisfied by the arguments of the Applicant and in view of our submissions made hereinabove, claim 1

of the subject patent is not anticipated by '247.

According to the expert of the respondent Prof. Dr Ing Jan Henning Lange the object of the patent is to provide a wind power installation with

reduced loading wherein the loading may occur by local temporary peaks in the wind speed in portions of the rotor area. According to the expert

Object of the patent:-

The object of the patent is to provide a wind power installation with reduced loading, wherein the loading may occur by local temporary peaks in the

wind speed in portions of the rotor area.

Solution of claim 1 and 22:-

IN 200 249 relates to a wind power installation comprising a rotor having a rotor hub and at least two rotor blades and the rotor blades are rotatable

along a longitudinal axis of the rotor blade (feature a). An adjusting device is provided for adjusting the angle of the rotor blade (feature b). The wind

power installation also comprises a generator coupled to the rotor, i.e. the generator is rotating when the rotor rotates due to the available wind

(feature c). At the rotor hub an ascertaining device for ascertaining a mechanical loading on the rotor hub or the blades is provided (feature d). The

wind power installation also comprises control means for determining a (new) blade angle (with respect to a rotation along the longitudinal axis of the

rotor blade) which is required for the reduction of the mechanical loading on the rotor hub or the rotor blade. The control means initiate the adjusting

device to adjust the blade angle of the rotor blade independently/asynchronously from the blade angles of the other rotor blades (feature e). The

control means are coupled to the ascertaining means and the measuring means (feature f).

If the wind speed is too high, the mechanical loading on parts of the rotor can be too high and exceed a given threshold value, such that the mechanical

loading must be reduced. This can be done by reducing the rotational speed of the rotor by adjusting the rotor blade angle. The mechanical loading on

the rotor hub or rotor blades is measured by measuring means. These measuring means are embodied as strain gauges 38 to directly measure the

mechanical loading according to the embodiment of Fig. 1.

GB 2 067 247

According to Prof. Lange GB 2 067 247 shows a wind power installation with rotor blades 4 which are mounted to a rotor 2 via a hub. Adjusting

devices 8 for rotating the rotor blades about their longitudinal axis are provided at the hub of the rotor (cf. page 1, lines 115-122). Furthermore, a

device to determine the wind energy to control wind power installations is provided. The device comprises pressure probes 10 arranged at the surface

of the rotor blades near their nose portions 11. This can be seen in Fig. 3 and 4 of GB '247:

The expert stated that this device for ascertaining the wind energy is based on the measurement of a pressure differential. The pressure probes are

provided at both sides of the rotor blade (nose or tip portion) preferably at a spacing from the rotor axis of 0.7 of the blade length (cf. page 1, lines 51-

59 and lines 60-67 as well as page 1, line 125-page 2 line 2).

He added that the initial angle of the wind ""a"" can be determined by the difference in pressure ascertained by the' probes 10. If the setting angle ""13ft

of the rotor blade, the pressure difference at the measurements points and the rotary speed of the rotor are known, then the wind speed prevailing

locally on the blade can be deduced from the pressure measurement values (ct. page 2, lines 6-13). By also using the values for air pressure,

temperature and the area of the rotor circle, the effective wind energy can be calculated in a further calculation process (ct. Page 2, lines 56-59). In

addition, a pressure probe for determining the total pressure may be arranged in front of the shaped nose or tip portion of the rotor blade (ct. page 1,

lines 70-73). If a multi-blade rotor with a joint adjustment of the blade is used, the measured values of all pressure probes on all the rotor blades must

be ascertained before the most favourable blade setting angle is calculated and is set to each rotor blade, i.e. the same blade an I value is set to each

rotor blade (ct. page 2, lines 20-25).

He stated that a distinct difference between the teachings of IN 200 249 and GB 2 067 247 is proven by the fact that the device described within

document requires a fallback solution to control the system outside its actual operating range, as the accuracy of the pressure probes is obviously not

sufficient at fairly small wind speeds. In this mode of operation, the system is controlled by a Robinson's anemometer being designated 16 in this

patent. Contrary to that, IN 200 249 does not disclose any requirement of a fall-back solution in order to control the system outside its actual operating

range, as the accuracy of the strain gauges seems to be sufficient for the control purpose in all modes of operation.

Furthermore, GB'247 does not teach that the control means ascertain a blade position required for the reduction in the instantaneous loading (of the

hub or the rotor blades) as it does not describe a way to determine the mechanical loading of the hub or the rotor blade. Thus, feature e) is not shown

here.

In summary, GB'247 does not teach to use measurement means to ascertain the mechanical loading of the hub or the rotor blades and it does not

teach to provide the measurement means in the rotor hub or elsewhere to determine the mechanical loading of hub or the rotor blades.

According to the expert the ""measurement means according to the subject matter of claim 1 are arranged in the hub and are used to ascertain the

instantaneous mechanical loading of the rotor hub or the rotor blades. The anemometer (16 in Fig. 4 within Patent '247) as described on page 2, lines

36-43 cannot be considered as measuring means in the meaning of the claim 1 of IN 200 249 as it only measures the wind speed and not any

mechanical loading on the hub or the rotor blades. The rotor hub is that part of the rotor to which the rotor blades are attached. Furthermore, the

anemometer 16 is not arranged in the rotor hub but outside the wind power installation as depicted in Fig. 4.

The control device according to GB'247 is not able to ascertain a new blade angle for the reduction of the mechanical loading as it does not describe

how the mechanical loading on the hub or the rotor blade could be determined. GB'247 only teaches to determine a pressure difference between both

sides of the rotor blades and adjust the rotor blade angles accordingly.

Expert stated that GB'247 does not describe that a mechanical loading is measured by measuring means arranged in the' rotor hub. In particular, this

patent does not describe the measurement of mechanical loading at all. The wind indicator as described on page 2, lines 60-64 and also in Fig. 4 is

arranged outside the wind power installation and not in the rotor hub. Furthermore, it does not describe that a blade angle position is ascertained to

reduce the mechanical loading and that the rotor blade is set to the ascertained blade angle to reduce the mechanical loading. There is absolutely no

mention of mechanical loading in the teaching of exhibit 2. In contrast GB '247, is directed to improve the measurement of the wind energy in the rotor

plane in order to achieve a good control (page 1, lines 25-28)

Hence, the subject matter of claim 1 and 22 is novel and inventive at least with respect to the teaching of exhibit 2.

If we see Claim 1 of the impugned patent as granted we find it states that 'rotor hub is provided with measurement means for ascertaining at least

one of the instantaneous mechanical loading of hub or a rotor blade' [identified as feature d by Dr Lang]. According to claim 2 the instantaneous

loading on the wind power installation is ascertained by the measurement means (38,40,44). If we see Fig 1, 38 refers to strain gauge secured to the

stub shaft, 40 refers strain gauges on the rotor hub and 44 refers to wind vanes mounted on rotor blade 16. In the CS it is further stated that that 'as an

alternative to measurement of the instantaneous loading on the wind power installation by means of strain gauges on the rotor hub and the stub shaft, it

is also possible to provide for loading measurement directly at the rotor blades by suitable strain gauges' [para 3 page 31]. It is further discloses that

'the anemometer or the wind vane or indicator, after comparison with the actual value of the adjusting drive, by means of the adjusting motor. Such an

instantaneous reaction to changes in loading in the region of the rotor blades ensures that harmful loadings or one-sided loadings on the rotor are

effectively avoided.'[page 26-27].It is also stated in CS that 'it should be noted that the various signals (that is to say 'load signal hub' 40, 'load signal

stub shaft' 38 'instantaneous angle a instantaneous 46 and 'afflux angle á' 53) which are used to ascertain the ideal rotor blade angle can be used

either jointly or also alternatively.[page 31 last para]

All this disclosure indicated that placement of measurement means such as strain gauge is possible at the rotor blades as an alternative position.

The applicant submission that 'pressure probes' in GB'247 are same as 'strain gauge' in impugned patent is acceptable as the most common method for

measuring load and pressure is by using a strain gauge-based transducer. A load cell is used to measure load which consists of an array of strain

gauges in which the measure of the deformation of a structural member is converts it into an electrical signal. Whereas Pressure transducers though

operate under the same principle as load cells, the strain gauges are mounted on a diaphragm where pressure is applied and the measure of the

deformation of the diaphragm which is proportional to the pressure is converted into electrical signal.

In GB'247 it is taught that' with device (pressure probe 10) according to the invention wind energy in rotor plane can be determined more

accurately than by conventional methods such as a measurement mast, or an anemometer on the extended shaft of the rotor'. It is further stated that

'a Robinson's anemometer 16 (fig 6) only serves to control the system outside its actual operating range.

Counsel for the respondent submitted that in GB '247 the anemometer (16 Fig 4) as described in the specification cannot be considered as

measuring means in the meaning of claim 1 of the GB patent as it only measures the wind speed and not any mechanical loading on hub or the rotor

blade. Further the anemometer is not arranged in the rotor hub but outside the wind power installation. Since an anemometer shows fairly small wind

speed more accurately than pressure probes, the control device is switched advantageously to anemometer when the wind drops or the wind rotor

becomes stationary. Only when the operating speed is reached the device switched over to wind measurement using pressure proves on the wing type

blades.'[Col 3 line 30-50]. It is also disclosed that the device of the invention in fact replaces use of special measurement mast to measure wind

energy.

In GB'247 it is taught that in operation the alignment of the wind during operation can be controlled by means of pressure probes measurements at

the wing type blade as well as by using the wind indicator 6. In the impugned patent wind vane is indicated by 44 and it is mounted on the rotor 16 for

measuring the afflux angle of the wind which meets the rotor blades.[page 11 line 8-11]. The wind vanes 44 are connected to the control device 8 (fig

1) by way of the electrical connection 52 as shown in fig 3.

In GB'247 it is taught that the anemometer 16 is provided for the purpose of determining the range of application of wind generator. In the

impugned patent it is stated that ""the various signals (that is to say load signal hub'40, ""load signal stub shaft ' 38, 'instantaneous angle à instantaneous'

46 and 'afflux angle á' 53) which are used to ascertain the ideal rotor blade angle can be used either jointly or also alternatively."" It is also stated in

GB 247 that ' (The device) improves the possibility of controlling the rotor for setting the blades and aligning the rotor in accordance with wind speed.

[Col 2 line 82-91]. Therefore claim 1 as granted is anticipated by the GB'247 as the rotor blade has at least one measuring means i.e. pressure probe

(10) for measuring the load which when used in conjunction with wind indicator 6 [used to measure wind direction] to control the alignment of the

wind during operation.

When we see the revised claims vide MP 47/11 we find claim 1 it is restricted to measuring means (40) being provided on the rotor hub for

ascertaining at least one of the instantaneous mechanical load of the hub thus modified claim 1 is not anticipated by GB'247 now as placement of

pressure probe is not found on hub in this citation. The applicant therefore succeeds in partially modifying the granted claims.

Person skilled in the art

Mr. Praveen Anand repeatedly urged us to decide the crucial issue 'Who is the person Skilled in The Art'. The guide to this is found in the

judgment of the MANU/DE/0381/2009 : 2012(52) PTC 1 (DEL) - F. Hoffmann-La Roche Ltd. & Anr. vs. Cipla Ltd.- It reads,

Therefore the same cannot be read to mean that there has to exist other qualities in the said person like un-imaginary nature of the person or any other

kind of person having distinct qualities."" and ""Was it for practical purposes obvious to a skilled worker in the field concerned, in the state of knowledge

existing at the date of the patent to be found in the literature then available to him, that he would or should make the invention the subject of the claim

concerned?

-

Mr. Anand submitted that the person of ordinary skill in the art should belong to the industry in India. The knowledge of the person of ordinary skill

in the art should be a cumulative result of various factors i.e. publication, know-how, planning, manufacturing, marketing etc. It is from the eyes of a

person of ordinary skill having the aforesaid knowledge, obviousness needs to be seen. He contended that there is no evidence by the Applicant to

establish who is a person of ordinary skill in the art.

The learned counsel submitted that the Applicant in paragraph 47 on page 11 of the revocation petition has tried to articulate a person skilled in the

art as an electronic engineer or an academician in the same field. However, the Applicant has failed to establish what is the experience or

specialization of the person skilled in the art. It is not sufficient to state that any electronic engineer or an academician in the relevant field is a person

skilled in the art. The onus is on the Applicant to prove if the person skilled in the art has 3 years of experience or 20 years of experience. It is

submitted that if an invention relates to automobiles, then a person skilled in the art may be a person doing research in automotive industry for certain

period of time. Similarly for an invention relating to aerodynamics, an engineer with specialty in aerodynamics and having relevant experience may be

considered as a skilled person. Therefore, the sweeping statement of the Applicant to include any electronic engineer without identifying the relevant

skill set is incorrect.

The learned counsel submitted that identifying a person of ordinary skill in the art is a separate chapter or proceedings and there is no thumping

order till date to direct how a person of ordinary skill in the art should be determined.

The learned counsel for the Applicant submitted that the Respondent's expert is not qualified to depose in this matter as that expert has no

knowledge or experience in the field of invention. The expert has the knowledge in the field of structural sciences and hence the expert opinion cannot

be relied upon.

We have already dealt with this question in detail in our order ORA/08/2009 in Para 25-37 [matter between same parties] and we adopt the same

here some relevant paragraphs are reproduced below.

There is nothing in the Act which limits the person skilled in the art and defines him as possessing certain qualities. In fact the Delhi High Court

frowns upon such a construction. The obviousness test is with reference to a person skilled in the art. That is all and not one who is residing in the

country performing experiments with local materials and in the laboratories specified. We may not do that in view of the Delhi High Court judgment,

which says we cannot read into the definition words that are not there. An inventive step is what is ""not obvious to a person skilled in the art.""(S. 2(1)

(ja)) Patents Act.) It does not say to an Indian skilled in the art working in an Indian Laboratory.

It is not as if the Act does not use a territorial limitation elsewhere. The words ""in India"" have been used in other contexts including enablement but

not with reference to obviousness. S. 25(1)(d) limits public knowledge and public use to such use and knowledge in India as a ground for opposition, as

does S. 25(2)(d). S. 25(1)(b) refers to complete specification published in India, as does S. 25(2)(b). The section concerned with revocation is also

patterned like wise and we find in S. 64(1)(e) relating to prior use and knowledge the word ""India"", in S. 64(1)(h) relating to enablement, the addressee

of the complete specifications is a person in India, in S. 64(1)(l) the secret use must take place in India, in S. 64(1)(q) the words used are ""India or

elsewhere."" in S. 64(2)(b) the knowledge and use in India is by importation. It is clear that the word India is used specifically if it is meant to be there.

But the Act requires us to look at a person skilled in the art which means knowledge of the state of the art and the skill to build on the knowledge in

order to decide if the invention is obvious. The Act does not say to a person in India who has ordinary skill in the art. Is this person timorous,

conservative, ordinary and incapable of venturing into sacrosanct areas? This person is neither described as ""ordinary"" nor ""average"".

In fact it is clear that in the context of enablement, the person to whom the complete specifications are addressed is a person ""who has average skill

and average knowledge."" Neither of these attributes has been assigned by the Act to the person to whom the invention should be non-obvious. We are

not called upon in this case to decide the person who is enabled. We are only pointing out to the difference in the words used in the Act. We do not

intend to visualise a person who has super skills, but we do not think we should make this person skilled in the art to be incapable of carrying out

anything but basic instructions. The Act makes a distinction between the person skilled in the art (the obviousness person) and the person who has

average skill (enablement man).

It is true that the Roche extract is specifically with regard to the Obviousness issue, but the Novartis extract is not. But it is clear from both the

judgments that we should understand the concepts based on the sections as they are in our Act, and also contextualise it in our country. Roche v.

Cipla also speaks of a person skilled in the art and not a person with ordinary skill in the art or average skill in the art. The respondent wants us to

imagine a person of ordinary skill, conservative, unimaginative, will not go against established prejudice, and is in India. The law has not used the word

ordinary"". It had the laws of other jurisdictions before it and yet it eschewed the word ""ordinary"". So it is very important for us while deciding

obviousness not to conjure up a dullard or a moron. Why should we proceed as if ""ordinariness"" is inherent in this hypothetical person? If it makes the

obviousness bar a bit higher, we must bear that in mind, for This Is Our Law.

We have already described this person in an earlier case Sankalp Rehabilitation Trust vs. Hoffman-Roche (OA/8/2009/PT/CH) where this Board

had also referred to KSR Int'l Co. v. Teleflex, Inc., MANU/USSC/0032/2007 : 550 U.S. 398 ""......he is no dullard. He has read the prior art and

knows how to proceed in the normal course of research with what he knows of the state of the art. He does not need to be guided along step by step.

He can work his way through. He reads the prior arts as a whole and allows himself to be taught by what is contained therein. He is neither picking

out the"" teaching towards passages"" like the challenger, nor is he seeking out the ""teaching away passages"", like the defender. In this case he is a

person familiar with or engaged in PEG chemistry. He knew that it was a time of intense activity in this field of chemistry. The person defending the

patent will undoubtedly inform the Court that there was nothing in the prior art to encourage the person skilled in the art to work toward the invention.

KSR says ""The question is not whether the combination was obvious to the patentee but whether the combination was obvious to the person skilled in

the art.

Under the correct analysis, any need or problem known in the field of endeavour at the time of invention and addressed by the patent can provide a

reason for combining the elements in the manner claimed."" And one of the easy ways by which ""a patent's subject matter can be proved obvious is by

noting that there was an obvious solution encompassed by the patent's claims."" KSR also says that if pursuit of known options within the technical

grasp of the person skilled art leads to the anticipated success "" it is likely the product not of innovation but of ordinary skill and common sense"". In the

words found in Roche v. Cipla this person is a skilled worker in the field concerned, with the state of knowledge existing at the date of the patent to be

found in the literature then available. There are no limitations or words in the Act to ""reduce"" this person's skill or knowledge.

In this case the art is wind energy. Since this obviousness test is the most frequently debated issue in patent litigations. It may be better if in the

future, the pleadings or evidence tells us who this person is. This person is skilled in the art. This person is presumed to know the state of that art at

that time, and to have the knowledge that is publicly available. The Act is quite clear and free of ambiguity. This person is skilled in the art and has

more than average knowledge of the state of the art and also has common sense. Indian law expects the non-obviousness to be tested against this

person and not the person who is the touchstone in U.S. Law. She is Ms. P. Sita (Person Skilled In The Art) and not Mr. Phosita or Mr. Posita who

are both ordinary by definition!

Obviousness

We shall now examine ground of obviousness as raised by the applicant. The counsel for the applicant submitted that the claims are obvious to the

person skilled in art.

The Applicant relied upon

EWEC 94 (Exhibit 3)

EWEC 96 (Exhibit 4)

GB 2067247 (Exhibit 2)

EWEC 94 (Exhibit 3)

According to the counsel this prior art relates to controller's influence on dynamic loads. It describes that the controller takes into account wind-based

dynamic loads and structural dynamics of the wind turbine. The effects of rotational asymmetries are also important but lead to more complex

controller structures (independent blade control). This clearly shows that this prior art deals with asynchronously adjusting the rotor blade settings

(Page 49, column 2, Para 2) (independent blade control and asynchronous adjustment of rotor blades being synonymous). He added that the rotor is

connected to the generator by a drive train and relied upon figure 3. [Page 50, Para 3.2]. It is stated that the control device for controlling all the

functions is very well known. [Para 5]. The counsel referred to figure 4 where conventional control system is shown and according to the counsel fig.

4(c) clearly depicts the control device which takes the input from measuring means and is also connected to adjusting device. He added that it is also

stated these kinds of control systems were used for simulations (Para-6 Simulations) [page 52]

The learned counsel contended that EWEC 94 clearly shows that a wind power installation having a measuring means and adjusting device

wherein these devices are connected to the control system. This prior art also shows the asynchronous setting of blades are possible and it also

discloses the measurement of mechanical loading on the drive train (rotor hub). Hence there is nothing inventive in claim 1 of the impugned patent.

According to the counsel the Respondent argued against this prior art on two grounds: 1. It does not disclose how the mechanical loading is

measured; and 2. The position of the measurement device is not disclosed.

The counsel for the applicant argued that the method by which the mechanical loading is measured is not claimed in any of the claims of the

impugned Patent. Further, the method has not been disclosed in the impugned patent specification. All that was disclosed was placing of, for example,

strain gauges in the rotor hub or stub shaft etc. Thus, this argument of the Respondent is not valid.

According to the counsel with regard to the position of the measurement means the it would be obvious for the skilled person to place the

measuring means at the locations where the loading has to be measured and to measure the mechanical load of the rotor the measuring means has to

be at the rotor, rotor hub, drive train, stub shaft etc, as the case may be.

EWEC 96 (Exhibit 4)

According to the counsel this prior art relates to reduction of fatigue loads on the main components as well as to satisfy the conventional control

aims (Page 57). Further, it discloses Para dynamic load model for HAWTs [Page 57], which states that the main concentration of the control system

would be on the torsion moment at the rotor shaft (rotor hub).Additionally, this prior art deals with asymmetrical loading on the components of the

machine. [Para 4 at Page 58]

According to the learned counsel the control system disclosed would help to reduce the fatigue loads on the drive train. He submitted that Figure 3

shows the structure of the control circuit which clearly shows that the load on the hub is measured. Thus, this prior art teaches that the control system

is connected to measurement means and adjusting means and is based on the mechanical loading (aerodynamic toque) of the hub. The prior art also

states that the following dynamic parameters of the test plant have particular influence on the controller design: [Point 4 at Page 59]

a. Pitch actuation time constant: 0.1s

b. Torque actuation time constant: 0.1s

The learned counsel argued that the test plant had a controller which could measures the pitch actuation and torque actuation every 0.1s and

hence the controller used, in this prior art had the ability to measure the variables instantaneously. He contended that EWEC 96 has the identical

advantages as the impugned patent and thus it would be very simple intelligence for a person skilled in the art to reach to the elements of claim 1.

GB 2067247 ('247)

The learned counsel submitted that the only difference between the claim 1 of impugned patent and the teachings of this prior art is that this prior

art does not teach the position of the measuring means on the hub and this difference would be obvious to a person skilled in the art.

The learned counsel submitted that invention and inventive step are two distinct terms and it is not necessary that contours of the two terms should

be co-terminus. He submitted that Section 2(ja), which defines ""inventive step"", gives a clear indication that the inventive step is a feature of the

invention. In other words invention and inventive steps may be different. While invention is identified by the claim as a whole, the inventive step,

involves identifying that feature in' the claim (invention) which involves technical advance as compared to existing knowledge or which shows

economic significance.

The learned counsel relied upon the principles enunciated by the Court of Appeal of United Kingdom in 1985 RPC 55 (Wind Surfing International

Inc. v. Tabur Marine Great Britain Limited). The said approach to obviousness was also restated by the High Court of Justice, Chancery Division,

Patent Courts in 2007 EWHC 2636 (Pat) between Mr. Aloys Wobben and Vestas Celtic Wind Technology Ltd.

According to the learned counsel applying the steps, laid down in the above cases, to the present case the following conclusion can be reached:

a) The inventive step embodied in claim 1 of the patent is the placement of the measuring means on the rotor hub to measure the mechanical loading

of the rotor.

b) The common general knowledge at the priority date of the patent is that all elements of Claim 1 are known such as measuring means, adjusting

means, control means, measuring and adjusting means being connected to the control means, individual blade adjustment etc. The prior arts do not

explicitly disclose that the measuring means is to be placed on the rotor hub, even though they disclose measurement of mechanical or dynamic loads

including load torque.

c) The difference between the matter cited in claim 1 and the common general knowledge on the priority date, if at all, is the placement of the

measuring means on the rotor hub.

d) Given that the objective is measuring the mechanical loading of the rotor and adjusting the rotor blade to reduce the said loading, the inevitable

choice for the person skilled in the art is to place the device on the rotor hub or on the rotor or on the stub shaft or the rotor blade and no technical

advancement is made by such placement.

e) Even if the placement is considered as a technical advance, that would have been obvious to the person skilled in the art.

In view of the above the learned counsel submitted that claim 1 is liable to be revoked under Section 64(1)(f).

Respondent's reply

The counsel for the respondent submitted that the Respondent has already demonstrated above that '247 fails to disclose a measuring means at the

rotor hub for ascertaining the instantaneous loading as neither the anemometer nor the pressure probes can be considered equivalent to the measuring

means of the present invention. Further as submitted above, the control means which ascertain a blade position for reduction in the instantaneous

loading is not disclosed in '247. Furthermore as submitted above, since measuring means is not present in '247, it cannot be said that it is connected to

the control means claimed in claim 1 of the subject patent. According to the counsel '247 discloses a totally different method of adjusting blade angles

in 0 § and 180§ position so that unequal wind angles at 90 § and 270 § are balanced. The system disclosed in '247 does not take into

consideration the situation when gusts take place. On the contrary, the invention claimed in the subject patent operates at all times i.e. the system

measures mechanical loading instantaneously i.e. at any instant. The Learned counsel argued that '247 is results in the reduction in structural loading

so that lighter and therefore cheaper wind generators may be built. Further, the reacting setting mechanism according to '247 is much lighter and

simpler (refer line 102 of '027). However, this is not the objective of the invention claimed in the subject patent.

The counsel submitted that the differential pressure measured by the pressure probes in '247 cannot be considered to be equivalent to the

instantaneous mechanical loading of the instant patent. Therefore, the teaching of '247 does not direct a person of ordinary skill towards the invention

claimed in the subject patent.

EWEC - 94

The learned counsel submitted that 'EWEC - 94' is a study to control system properties and dynamic loads on horizontal axis wind turbines. The

aim of EWEC - 94 is to investigate the controller's influence on dynamic loads in detail and to find appropriate controller structures performing load

reduction (column 1, para 4 on page 415 under the heading 'introduction'). Therefore, a person of ordinary skill in the art would consider this document

to modify the controller design and not to place strain gauges on the rotor hub.

The learned counsel submitted that the controller design described in EWEC - 94 takes into account wind caused dynamic loads and structural

dynamics of the wind turbine. The effects of rotational asymmetries are also important but lead to more complex controller structures (column 2, para

2 on page 415 under the heading 'Causes of Dynamic Loads on WECs'). Therefore, EWEC -94 realizes the complexity in considering the

asymmetries or independent blade control as claimed in the subject patent and hence does not deal with it. If the complexity of such kind arises, then

the controller disclosed in EWEC - 94 would be redesigned.

The learned counsel submitted that EWEC - 94 deals with effects of dynamic loads of wind power installations. In chapter 4, the axial and

tangential aerodynamic forces on the blades are derived as functions of the wind speed components by equations. Also, the effects of a pitch

adjustment on the mechanical loading are described. In EWEC - 94, the emphasis is placed on the requirement that the pitch angle must follow the

angle of inflow with low time delay and that the pitch angle must be kept sufficiently close to the angle of inflow to avoid stall operation. According to

EWEC - 94, the rotor shaft torque can be regarded as a suitable quantity representing the mechanical loads on the drive train, (column 1, lines 7-9

under the heading '3.1 Torsional Loads on the Drive Train').

The learned counsel submitted that different types of controller structures are presented in EWEC - 94 which allow the control of dynamic loads

using the electrical power output as an input value for generator torque and thus for rotor shaft torque control. EWEC - 94 clearly explains that the

mechanical load quantities of the rotor blades are derived from the electrical power and the rotor speed by an estimating filter (column 1, para 1, lines

9-10 under the heading 'Controller Design'). It is submitted that an estimating filter can estimate the mechanical load quantities, which can never be

accurate. Further, the estimating filter of EWEC - 94 cannot measure instantaneous mechanical loading. In other words, the estimating filter cannot

measure the mechanical loading at any instant as is done by the invention claimed in the subject patent. It is submitted that the present invention

protects the wind power installation from extreme conditions, such as unpredictable gusts, by instantaneously measuring the mechanical loading on the

rotor hub. However, the estimating filter as described in EWEC - 94 cannot perform this function. He added that the estimating filter in EWEC - 94

estimates ""non-measurable load quantities"" (column 2, para 2, lines 2-4 under the heading 'conclusion'). Therefore, even the mechanical loadings

described in EWEC - 94 are non-measurable as these are estimated by the estimating filter. On the contrary, the invention claimed in the subject

patent provides a distinct solution to directly measure instantaneous mechanical loading, e.g. by the use of strain gauges. Therefore, even if a person

of ordinary skill in the art considers combining the teachings of '247 and EWEC - 94, she would not arrive at the invention claimed in claim 1 of the

subject patent as both the documents fail to disclose how to measure the instantaneous mechanical loading on the rotor hub and where to arrange the

measuring means. Thus, the invention claimed in claim 1 of the subject patent involves inventive step in view of '247 and EWEC - 94.

EWEC - 96

The learned counsel submitted that EWEC - 96 is a study by way of simulations and experiments for load reduction by multivariable control of

wind energy converters. It is submitted that there is no teaching in EWEC - 96 of measuring instantaneous mechanical loading on the rotor hub.

EWEC - 96 describes a control system which takes into account mechanical loading on part of the wind power installation. However, EWEC - 96 is

silent with respect to a method or device by which the instantaneous mechanical loading could be measured directly. EWEC - 96 clearly states that as

controller input values only reliable measurable quantities may be used and assumes the electrical power, the generator rpm and the blade pitch angle

to be available for that purpose (first column, last four lines and second column, first line on page 822).

According to the counsel EWEC - 96 further describes the structural dynamics, e.g. the '"" edgewise bending moment and the flap-wise bending

moment. He added that these structural dynamics are estimated by the use of numerical models only. On the contrary, the invention claimed in the

subject patent provides a distinct solution to directly measure load quantities, e.g. by the use of strain gauges.

The learned counsel submitted that submitted that the special sensors described in referred to in EWEC - 96 are not part of the control system but

are used only for the experiments which are used to the function and practicability of the control system described in EWEC - 96. Further, the nature

of these sensors remains totally unclear and hence, to consider such special sensors with the measurement means of the present invention is nothing

but a hindsight approach by the Applicant. Therefore, even by combining '247 with EWEC - 96, a person skilled in the art would not arrive at the

invention claimed in claim 1 of the subject patent. Thus, the invention claimed in claim 1 of the subject patent involves inventive step in view of '247

and EWEC - 96.

US 1437433 ('433)

The learned counsel submitted that this document is cited to allege that strain gauges are one type of pressure probes. It is submitted that this

allegationø of the Applicant is completely incorrect and is based on incorrect understanding of the subject matter disclosed in '433. He submitted that

'433 relates to a hydrostatic transmission system which controls the movement of loads and designed more specifically, although not exclusively, for

load hoists (page 1, lines 9-12). Thus, the technical field of this document is completely unrelated to the field of the subject patent i.e. wind power

installations. It is submitted that the probe 20 which is in the form of a strain gauge in '433 serves to indirectly measure the value of the resisting torque

offered by the (hoisted) load 22 which is proportional to the elastic elongation of the link 33 (page 4, lines 3-7). According to '433 this resisting torque

can obviously and alternatively be measured by any other probe arranged at any other point (page 4, line 114-117) e.g. by a pressure probe or a strain

gauge arranged on a (hydraulic) ram replacing the link 33 (page 4, line 122-124). In this case, it is submitted that the pressure probe would measure

the oil pressure inside the ram while the strain gauge would measure the plastic elongation of the ram's plunger. The interpretation of the Applicant

that strain gauges are one kind of pressure probes is thus completely incorrect and misleading. The correct interpretation would be that in case of the

device described in '433, a strain gauge or pressure probe could be used alternatively for the described purpose depending on the variant form of

embodiment. However, it must be, considered that the teaching of Patent '433 relates to high level loads which occur in hydraulic circuits or hoists, but

not to low level loads which occur in a pressure probe. In order to achieve a sufficient resolution, such kinds of pressure probes are therefore based

on various technical principles but not on conventional strain gauges. A person skilled in the art dealing with wind power installations would therefore

not consider the teaching of this '433. Without prejudice, even if a person skilled in the art considers '433, she would not find a suitable teaching in this

document. Therefore, the invention claimed in claim 1 of the subject patent involves inventive step in view of '247 and '433.

The counsel for the respondent relied on expert evidence of Prof. Dr Ing Jan Henning Lange. Let us see what the expert said about the citations.

EWEC-94 [Exhibit 3]

According to expert 'this documents relates to the effects of dynamic loads of wind power installations. In chapter 4, the axial and tangential

aerodynamical forces on the blades are derived as functions of the wind speed components by equations. Also, the effects of a pitch adjustment (a

change of the blade angle about the longitudinal axis of the rotor blade) on the mechanical loading is described. Special emphasis is placed to the

requirement that the pitch angle must follow the angle of inflow with low time delay and that the pitch angle must be kept sufficiently close to the

angle of inflow to avoid stall operation. Exhibit 3 says that ""the rotor shaft torque can be regarded as a suit-able quantity representing the mechanical

loads on the drive train"" (ct. page 416, lines 10-12). Different types of controller structures are presented which allow to control the dynamic loads

using the electrical power output as an input value for generator torque and thus for rotor shaft torque control. It is clearly explained that the

mechanical load quantities of the rotor blades are derived from the electrical power and the rotor speed by an estimating filter (cf. page 418, lines 8-

10). However, this document is completely silent with respect to any method or device by which the instantaneous mechanical loading could be

measured directly. In particular, exhibit 3 is silent with respect to the nature and location any measuring means for direct measuring of the

instantaneous mechanical loading on the rotor/rotor blades or the rotor shaft. More-over, according to my understanding, the instantaneous mechanical

loads of the sys-tem are described as non measurable load quantities in Exhibit 3 (cf. page 418, line 69). Contrary to that, IN 200 249 compromises a

distinct solution to directly measure such load quantities, e.g. by the use of strain gauges.

Hence, the subject matter of claim 1 and 22 is novel as well as inventive with respect to Exhibit 3.

Exhibit 2

'Exhibit 2 relates to a device for determining the wind energy in the rotor plane of wind generators and to the control of the wind power installation

according to the deter-mined wind energy. The wind energy is determined based on a pressure difference between both sides of the rotor blades.

According to the sensed pressure difference, the blade angle of the rotor blades is adjusted to optimize the power output. With the device according to

exhibit 2 a more accurate measurement of the wind energy is possible. However, exhibit 2 is not related to the instantaneous mechanical loading on

the rotor hub or the rotor blades. Therefore, it is not clear why a person skilled in the art should consider the teaching of exhibit 3 when he is working

with the teaching of exhibit 2.

Accordingly even if a person skilled in the art would consider combining the teachings of Exhibit 2 and 3, such a combination would not lead to the

subject matter of claim 1 as both documents do not describe how to measure the mechanical loading and where to arrange the measuring means:-

According to Exhibit 3, the mechanical loading is even ""non-measurable

EWEC-96 [Exhibit 4]

'Exhibit 4 (EWEC-96) describes a control system-which takes into account mechanical loading on part of the wind power installation. However, as the

case with exhibit 3, exhibit 4 is silent with respect to any method or device by which the instantaneous mechanical loading could be measured directly~

Moreover, exhibit 4 is silent with respect to the nature and location of any measuring means for direct measuring of the instantaneous mechanical

loading on the rotor/rotor blades or the rotor shaft, exhibit 4 clearly states that as controller input values only reliable measurable quantities may be

used and assumes the electrical power, the generator rpn and the blade pitch angle to be available for that purpose (ct. page 822, last four lines of 1st

column and first line of 2nd column). The structural dynamics, e.g. the edgewise bending moment and the flap-wise bending moment, are described

and estimated by the use of numerical models only. Contrary to that, IN 200 249 comprises a distinct solution to directly measure such load quantities,

e.g. by the use of strain gauges.'

'The special sensors, to which para 58 of the Revocation Petition refers, are not part of the control system described in Exhibit 4, but are part only of

the experimental setup which is to verify the function and practicability of the control system described in Exhibit 4. The nature of these sensors

remains totally unclear. Accordingly, there is absolutely no reason to consider these special sensors in this case.'

Even if a person skilled in the art would consider combining the teachings of exhibit 2, 3 and 4, such a combination would not lead to the subject matter

of claim 1 as none of these documents describe how to measure the mechanical loading and where to arrange the measuring means.'

Accordingly, the claims 1 and 22 are also inventive and prima facie valid.

In respect of Mr. Dlip Trasi Expert of the applicant Mr. Lang stated that

'GB '247 only discloses that pressure probes are provided which are arranged at the tip portion of the rotor blade at both sides of the rotor blade to

determine a pressure difference in order to calculate the wind energy. In addition, a pressure probe for determining the total pressure may 00 arranged

in front of the shaped nose or tip portion of the rotor blade. Accordingly, feature d) is not shown in GB '247 as the measurement means according to

GB 247 are pressure probes which are neither arranged in the rotor hub nor in any other portion of the region of the rotor except the blades.

Furthermore, the pressure probes can only detect a pressure or pressure differential-but clearly not detect directly an instantaneous mechanical

loading on the rotor hub or the rotor blades-

It might be possible to derive a mechanical loading on the overall wind power installation if the wind speed is known, but it is not possible to derive the

actual mechanical loading on the rotor hub or the rotor blades. Even if, this would only be a derived value and not a measured value, i.e. it would not

be very accurate. Moreover, it would not be possible to derive the exact mechanical loading on each rotor blade as wind conditions might be different

locally.

It should be noted that the anemometer according to GB '247 is only able to measure a wind speed and not to measure a mechanical loading on the

rotor hub or rotor blades. Moreover, the anemometer is arranged outside (behind the gondola with respect to the wind direction) of the rotor 2. Thus, it

does not fulfill the two features of d) namely that the measuring means are arranged in the rotor hub and that they measure the mechanical loading on

the rotor hub or the rotor blade.'

'In addition, the adjustment of blade angles of the rotor blades according to GB '247 is not performed based on a measured mechanical loading on the

rotor hub or the rotor blades but merely based on the pressure difference measured to determine the wind energy. There is absolutely no mention on

the measurement of mechanical loading on the hub or the rotor blades, i.e. feature d) is not disclosed in GB '247.'

US 1,437,433

US 1,437,433 is related to hydrostatic transmission systems controlling the movement of loads and designed more specifically, although not exclusively,

for load hoists (ct. page 1, line 9-12). Because of this, according to my understanding, this document is related to a technical field completely unrelated

to the field of wind power installations. In para 63 of the revocation petition it is mentioned that ""the probe 20 can be replaced by a pressure probe

(strain gauge) arranged on a ram replacing the link 33"" from which the originator of this paragraph concludes that strain gauges are one kind of

pressure probes and hence on the combined reading of '247 Application and '433 Patent, the claimed invention would be obvious to a person skilled in

the art. How-ever, reading the teaching of '433 it quickly becomes evident to a person skilled in the art, that the probe 20 which is in the form of a

strain gauge in the described embodiment serves to indirectly measure the value of the resisting torque offered by the (hoisted) load 22 which is

proportional to the elastic elongation of the link 33 (ct. page 4, lines 3-7). It is also explained that this resisting torque can obviously and alternatively be

measured by any other probe arranged at any other point (ct. page 4, line 114-117), e.g. by a pressure probe or a strain gauge arranged on a

(hydraulic) ram replacing the link 33 (ct. page 4, line 122-124). In this case, according to my understanding, the pressure probe would measure the oil

pressure inside the ram, while. the strain gauge would measure the elastic elongation of the ram's plunger. The interpretation according to para 63 of

the revocation petition that strain gauges are one kind of pressure probes is therefore totally misleading. The correct interpretation would be that in

case of the device described in Patent '433, a strain gauge or pressure probe could be used alternatively for the described purpose depending on the

variant form of embodiment However, it must be considered that the teaching of Patent '433 relates to high level loads which occur in hydraulic

circuits or hoists, but not to low level loads which occur in a pressure probe serving as an anemometer. In order to achieve a sufficient resolution such

kinds of pressure probes are therefore based on various technical principles but not on conventional strain gauges. A person skilled in the art dealing

with wind power installations would therefore not consider the teaching of this document and, even if, would not find a suitable teaching. Therefore,

US '433 is definitely not relevant.

US 5,426,217 is relating to measuring forces when a rotary body such as a wheel is clamped on a testing machine. US '217 therefore relates to a

completely different technical field which is not at all related to wind energy. This becomes evident e.g. if one takes into consideration the different

environmental conditions under which a testing machine and a wind power installation operate or, as another example, the different requirements

which have to be fulfilled with regard to life span, maintainability, and safety. Moreover, US '217 aims to measure external clamping forces, while it

does not aim to measure the internal mechanical loading of any component. A further aim of US '217 is to enable the adjustment I correction of

clamping forces during operation In order to avoid markings on the surface of the rotary member to be tested, but it does not aim to reduce the internal

mechanical loading of any component of the testing device itself. Contrary to this, IN 200 249 aims to measure the internal mechanical loading of

components of its own structure and it also aims to reduce the internal mechanical loading of components of its own structure. A person skilled in the

art dealing with wind power installations would therefore not consider the teaching of this document and, even if, would not find a suitable teaching.

Therefore, US '217 is not relevant.

US 4,474,531

The cited Patent US 4,474,531 is relating to a system that allows detecting the relative angle between a wind vane and the turbine shaft of the

windmill and by this allows activating the pitch-control mechanism of the windmill to feather the windmill blades whenever the angle exceeds a

predetermined maximum. It also describes the mechanism by which the blade pitch is controlled, namely in form of an actuating rod that extends

coaxially within the turbine shaft and rotates with it but is axially moveable with respect to it. The pitch of the blades varies with the axial position of

the actuating rod, and the actuating rod threadedly engages an actuating nut that can be rotated with respect to the turbine shaft. Therefore, the

actuating rod moves axially with respect to the shaft if there is a relative rotation between the shaft and the nut. The blade pitch then remains the

same so long as the actuating nut spins at the same ratio as the shaft does (ct. page 4, 1st column, lines 22-33). A person skilled in the art will easily

understand from this description that this system does not allow to adjust the pitch of the blades individually which is contrary to the teaching of IN 200

249, where the blade pitch actuating mechanism allows an individual pitch adjustment of the blades. Also, referring to page 10, lines 17-25 of IN 200

249, the adjusting motor and the adjusting transmission are mounted on the flange connection between the rotor blades and the hub, which is also

depicted in Fig. 1 of IN 200 249, while according to the teaching of US '531 a servomotor rotates the actuating nut that threadedly engages to the

actuating rod which extends coaxially within the turbine shaft and rotates with it. A person skilled in the art will easily understand that the blade pitch

control devices described in US '531 and IN 200249 are based on totally different technical solutions and would therefore not consider the teaching of

this document and, even if, would not find a suitable teaching. Therefore, US '531 is not relevant.

Therefore, according to my understanding, the affidavit of Mr. Trasi does not prove the lack of novelty or lack of inventive step. Therefore, the claims

of the subject patent are valid.

The learned counsel for the Applicant submitted that the expert is trying to differentiate the prior art on the ground that the strain gauges

(measuring means) measures the mechanical load directly whereas it was not possible in the prior art. He submitted that such limitation i.e. measuring

directly has neither been claimed in any of the claims nor disclosed in the specification anywhere. In any case, placing a strain gauge on the rotor hub

would measure the loading and no technical contribution or advance is made in measuring the same ""directly"". The learned counsel submitted that the

expert also differentiated the prior arts on the ground that the placement of the measurement means is not disclosed in the prior art. The Applicant

reiterated its arguments on this point and stated that this argument is not valid.

The question before now is to find whether shifting of pressure probes from blade (known in GK 297) to the rotor hub in Impugned patent is a

technical advance when compared with the exiting knowledge. The expert of the respondent also posed this question as 'how to measure the

mechanical loading and where to arrange the measuring means.' We do not agree with respondent that pressure probe and strain gauge are different

devices as we have already found both devices are performing same function of determining mechanical load. The prior art (GK297) taught an

pressure probe (in the rotor blade) for measuring the wind energy or mechanical load at rotor blade section. There was no prior art which shows that

the pressure probe is located on the rotor hub. EWEC 94 teaches that 'one possible controller structure for the realization of dynamic load reduction

has been introduced. It uses independent control of pitch angle and generator torque and include a filter to estimate non measurable loads quantities.'

The respondent argued that the estimating filter in EWEC 94 cannot measure the mechanical loading at any instant as is done by the invention claimed

in the subject patent. If we see EWCE 96 it states that 'Guidelines for determination of wind turbine loads are fixed in standards.[para 2] and to

investigate the controllers influence it is sufficient to concentrate on the following main load quantities:

- the flapwise bending moment at the blade root

- the edgewise bending moment at the blade root

- the torsion moment at root shaft

- the bending moment at the tower base.

as shown in Fig 1.

The respondent argued that though EWCE 96 'describe a control system which takes mechanical loadings as part of wind power installation into

account but it silent with respect to the manner as to how the mechanical loading is measured' and it 'is silent with respect to the location of any

measuring means for measuring the mechanical load. [para 4(x) of reply]

In view of GB 247 the respondent has given up the location of measuring means at the rotor blades which is admitted in the specification as an

alternative. The claim 1 as worded require that ' said rotor hub is provided with measurement means for ascertaining at least one of the instantaneous

mechanical loading of the hub or a rotor blade ...'It is admitted fact that in the known wind power installations, the speed of rotor rotation and the

power output can be regulated by means of a regulating system for the angle of incidence of the rotor blade. In CS that 'In that respect there are

essentially two ways two ways of producing a reduction in the speed of rotor rotation, by means of rotor blade adjustment i.e. either by reducing the

blade setting angle in the direction of smaller aerodynamic angles of incidence in order thereby to reduce the power consumption of the rotor or by

adjusting the rotor blade setting angle to larger angles to achieve the critical aerodynamic angle of incidence, the so-called stall condition.' (Page 2 third

paragraph). It further stated in CS both these above mentioned procedures in the state of the art do not take account of the fact that, particularly when

a large rotor diameter is involved, there can be a no uniform distribution of the wind conditions over the area of the rotor. That in turn results in

different loadings on individual rotor blades as well as asymmetrical loadings for the drive train of the wind power installation, that is to say the hub, the

drive shaft and the respective bearings. (page 31st para) This stated as the problem. The specification further states that the regulating device known

hitherto from state of the art cannot therefore react to fluctuations in wind speed and fluctuations in load, which are related therefore in the region of

the rotor, as the known installations provide for uniform synchronous adjustment of the rotor blades. In the next it is admitted that in modem

installations individual electrical adjustment of each individual rotor blade has been proposed. (Page 2 para 2)

That being prior knowledge, in other words the asynchronous adjustment of one rotor blade is also admittedly known. In the known installations all

blades being adjusted simultaneously and synchronously. Therefore the object of the invention is to provide a method and wind power installation to

reduce the loadings which can occur by virtue of local, temporary peaks in the wind speed in portions of the rotor area. In order to achieve the above

said objective, in a wind power installation are provided measuring means for ascertaining the instantaneous loading of a part of the wind power

installation [Hub or rotor blade], control means for ascertain a position of at least one rotor blade wanted for the instantaneous load and for suitable

adjusting the rotor blade by means of adjusting means. The connecting means are for connecting the adjusting device and measuring means to the

controller. Fig 3 explains the circuit arrangement.

Figure 3

Now if we see circuit arrangement shown in Fig 3 of EWCE 96

We find the circuit arrangement is same where the inputs like aerodynamic torque, thrust and wind velocity are feed in the estimator. The inventive

step in claimed invention is a wind power installation wherein the location of the measurement means i.e. measuring device located on the rotor hub.

The said measurement means as claimed in claims 1 and 2 are measurement means (38,40,44) but in claims 3,4,6-14 they are given as 'measuring

means (38,40,44)' and claim 13 states 'measuring means (38,40,44) for measuring the load have strain gauges (38,40). In claim 17 it is stated that

input means (38), which is connected to the controller 8 for in putting the desired position of the rotor blades or blades for a given instantaneous

loading.

The learned counsel for the respondent tried to explain that the 'measuring means (38,40,44)' in claims are not correctly depicted and proposed to

amend the claims and file MP 47/2011. We have already dealt with amendments above.

We have with us the teaching of EWCE 96 for dynamic load model for HAWTs. Now if we see the standard guidelines given in EWCE 96 for

dynamic load model for HAWTs we find position of the measuring means (strain gauge 38) on the rotor hub was other alternative choice for the

skilled person as the objective was to measure the mechanical loading on the wind power installation and pass on the said information to control device

8 to redefine the rotor blade angle. The circuit arrangement in Fig 3 in EWCE 96 is same as in Fig 3 of impugned patent. We do not find any technical

advance in providing the measuring device at hub as an alternative to measuring device (pressure probe) on the rotor blade was known in the of GB'

The expert of the respondent has differentiate the impugned patent from the prior art by stating that the strain gauges (measuring means)

measures the mechanical load directly whereas it was not possible in the prior art. We find this argument not convincing as placing a strain gauge on

the rotor hub would measure the mechanical loading and no technical advance is made in measuring it directly as same would be done when the

measuring gauge is place at rotor blade or any other location. There is nothing in specification to show that this location of strain gauge is best among

other locations. Finally, in the specification the applicant has admitted that it is possible to provide for loading measurement directly at the rotor blade

by suitable strain gauges. [the last but one para] Therefore, the impugned patent is obvious in view of teaching of GB '247 and EWCE 96. Finally we

find the claims as originally filed cannot be accepted they are partially anticipated and the claimed invention is found to be obvious and when the

conduct of the respondent is one of the reasons for not allowing the amendment, we are inclined to allow the revocation application. The

ORA/39/2009/PT/CH is allowed and Patent No. 200249 is revoked. Consequently Miscellaneous Petition Nos. 16/2010 (for stay), 41/2010 (for urgent

hearing cum stay of operation), 76/2010 (for dismissal), and 22/2013 (for stay of hearing) are closed. Miscellaneous Petition No. 47/2011 (for

amendment of claims) is ordered.