T 0500/20 - The argument unfortunately heard ever more often

Key points

• This decision has already been discussed on various other blogs. 
• "The Board adds that the general argument, made in this case and unfortunately heard ever more often not only in the present field [i.e. wind turbines] but more widely in mechanics, that the invention would not be sufficiently disclosed across the entire breadth of the claim misapplies an approach developed mainly in the field of chemistry for inventions where a central aspect of the claimed invention is a range of compositions or of parameter values"
• The Board is probably referring to T 939/92 regarding inventive step ( "The question as to whether or not such a technical effect is achieved by all the chemical compounds covered by such a claim may properly arise under Article 56 EPC, if this technical effect turns out to be the sole reason for the alleged inventiveness of these compounds")
• "In claimed inventions that do not involve a range of parameter values or compositions basing an argument of insufficiency on this approach is inappropriate and can be rejected offhand for that reason. This is especially so where, as in the present case, an invention is directed at a broadly defined concept expressed in terms of generic structural or functional features of an apparatus or of a method. There it normally suffices to provide a single detailed example or embodiment to illustrate how this concept can be put into practice, cf. CLBA, II.5.2., in such a way that the underlying principles can be understood by the relevant skilled person and they can reproduce the claimed invention using their common general knowledge without undue burden, CLBA, II.4.1. "
• " It is thus not enough to demonstrate insufficiency to conceive of an example falling within the terms of the claim that does not work because it does not achieve the claimed effect fully or at all. Such an example does not prove that the claimed concept does not work; rather it reflects the limitations that are inherent in any technological endeavour and which may provide the scope for future (inventive) development. "
• " To successively argue insufficiency in a case such as this a very high burden of proof applies: the party must demonstrate through cogent argument based on the underlying principles, if necessary supported by evidence, that the claimed concept does not work, because it does not achieve the desired effect in any measure or indeed is counter to the laws of nature. Or they must demonstrate that the disclosure lacks information on an important aspect of the claimed invention, without which the skilled person cannot realize the claimed invention without undue burden. The appellant [opponent] has failed to present any such arguments in the present case."
• "The invention relates to a wind turbine and a method for controlling a wind turbine in an idling power producing situation, see specification paragraphs [0001], [0007] and [0011]. The wind turbine control and method is aimed at damping or eliminating undesirable edgewise oscillations of the rotor blades that may appear in an idling power producing situation, see paragraphs [0003], [0007]. The control of the wind turbine alters the nacelle yaw angle if it detects the presence of blade edgewise oscillations. Changing the yaw angle changes the conditions that influence the presence of edgewise oscillations to dampen or eliminate them"
• The claim at issue recites:  "said yaw controlling system is adapted for changing the yaw position of the wind turbine nacelle (3) when ...said detection means (21) detects edgewise oscillations in one or more of said rotor blades (5), [t]hereby damping or eliminating said edge-wise oscillations". Hence, the desired result is specified in the claim. 
• " Nor does the Board have any difficulty whatsoever in understanding how the invention works when it considers the description and figures. In their view the exact workings of the claimed invention are amply clear to a skilled reader if they genuinely approach the patent and its disclosure constructively, with a sincere willingness to understand. Paragraphs [0074]-[0078] of the patent indicate sufficiently clearly to the skilled person how to carry out damping or eliminating of edgewise oscillations by changing the yaw position (claims 1 and 11) and also how to so reach an oscillation minimum (claim 8)."
•  "as variously stated in case law, these isolated cases of non-working or not ideally working embodiments is of no import for the issue of sufficiency in the light of the large number of conceivable and realisable alternatives (see above) indicated in the description, cf. in this respect G 1/03 reasons 2.5.2, T 0857/16 reasons 35."
• The present Board: " in the field of chemistry for inventions where a central aspect of the claimed invention is a range of compositions or of parameter values, ... it is important that an effect associated in the patent with the range is plausible or plausibly demonstrated across the whole breadth of the claimed range (leaving aside issues of proof of plausibility, the subject of current referral G2/21). Otherwise the claimed invention would be insufficiently disclosed, because the effect is not plausible across the whole breadth of the range."
• Plausibility in the sense of G 2/21 refers to inventive step, of course. The technical effect is also a concept associated with inventive step unless it is recited in the claims. The Board's summary of the perceived case law in the field of chemistry seems somewhat inaccurate. 
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EPO 

The link to the decision is provided after the jump, as well as (an extract of) the text of the decision.

https://www.epo.org/law-practice/case-law-appeals/recent/t200500eu1.html

Reasons for the Decision

1. The appeal is admissible.

2. Background.

The invention relates to a wind turbine and a method for controlling a wind turbine in an idling power producing situation, see specification paragraphs [0001], [0007] and [0011]. The wind turbine control and method is aimed at damping or eliminating undesirable edgewise oscillations of the rotor blades that may appear in an idling power producing situation, see paragraphs [0003], [0007]. The control of the wind turbine alters the nacelle yaw angle if it detects the presence of blade edgewise oscillations. Changing the yaw angle changes the conditions that influence the presence of edgewise oscillations to dampen or eliminate them, see paragraphs [0008]-[0010].

3. Main request - Sufficiency of disclosure

3.1 The appellant contests the division's finding that the claimed invention is sufficiently disclosed, cf. section 2 of the impugned decision.

3.2 The appellant objects, for both claim 1 and claim 11, that the invention cannot be carried out due to a contradiction of claim features. The claim requires to change the nacelle yaw position while the turbine is at idle, the latter in their view meaning that no operation at all (including change in nacelle yaw position) is possible.

However, the Board finds that such a contradiction neither exists in the claim language nor in the accompanying description. The term "idling" is generally understood as meaning "to run while disconnected from load or out of gear, so that it performs no external or useful work" (OED). In the field of wind turbines this simply means that the turbine runs but without generating power, normally when not coupled to the power grid (German: "Leerlauf"). The skilled person, an engineer designing and developing wind turbines, will have no difficulty whatsoever understanding the term either in claim context or in the description. Indeed this understanding is confirmed by the explicit statement in the claim, an idling power producing situation of said wind turbine in relation to a utility grid. Other operations, like nacelle yaw change, are not required to be suspended to meet this claim feature, see also the explicit definition of the expression in paragraph [0011] of the description. Thus, the argument that there would be some "contradiction" is a spurious one.

3.3 Nor does the Board have any difficulty whatsoever in understanding how the invention works when it considers the description and figures. In their view the exact workings of the claimed invention are amply clear to a skilled reader if they genuinely approach the patent and its disclosure constructively, with a sincere willingness to understand. Paragraphs [0074]-[0078] of the patent indicate sufficiently clearly to the skilled person how to carry out damping or eliminating of edgewise oscillations by changing the yaw position (claims 1 and 11) and also how to so reach an oscillation minimum (claim 8). It may be done by an iterative process until a minimum value has been reached or alternatively until a value below a certain threshold, and/or on the basis of previously obtained data which may also include trend values calculated from previously obtained data stored in the control's memory. Specific values of yaw angle changing speed or choice of positive/negative sense for individual embodiments belong in the Board's view to the skilled person's routine design practice and are not needed in the patent specification description.

3.4 Nor does the Board identify any difficulty for the skilled person to carry out indirect detection of an idling condition by a rotation speed sensor as described in paragraph [0069]. As explained there, null or low rotating speeds can indicate that the wind turbine is idling.

3.5 As regard edgewise oscillation detection, specification paragraphs [0012]-[0019] provide examples of how these can be detected. For instance in paragraphs [0013]-[0015], detection is by load sensors or accelerometers placed in or on the blade to provide information on blade load, including load shifting between the blade's trailing and the leading edges, indicating edgewise oscillations as opposed to say load shifts in other directions. The appellant's objection of lack of information on how to differentiate edgewise and flapwise oscillations is also without merit.

This is also the case for the objection against claim 3, that the disclosure would be insufficient as to how to detect edgewise oscillations with acceleration sensors placed in a nacelle, see specification paragraph [0064]. As indicated there, blade edgewise oscillations induce nacelle oscillations in the yawing direction at frequency values that correspond to the first blade edgewise natural frequency, in the described example in the interval of 0.9-1.8 Hz. Proper placement of the sensor measurement direction and/or frequency bandpass filter or similar can thus readily be used to isolate the oscillation component associated with the blade edgewise oscillations. Similar frequency filtering can be used for any other type of sensor and other locations as generally described in paragraph [0065]. It might be (as a matter of speculation) that for some special wind turbine design this frequency happens to be close to the resonance frequency of some other component of the turbine, which would distort detection of edge-wise oscillation. However, as variously stated in case law, these isolated cases of non-working or not ideally working embodiments is of no import for the issue of sufficiency in the light of the large number of conceivable and realisable alternatives (see above) indicated in the description, cf. in this respect G 1/03 reasons 2.5.2, T 0857/16 reasons 35.

3.6 The Board adds that the general argument, made in this case and unfortunately heard ever more often not only in the present field but more widely in mechanics, that the invention would not be sufficiently disclosed across the entire breadth of the claim misapplies an approach developed mainly in the field of chemistry for inventions where a central aspect of the claimed invention is a range of compositions or of parameter values, cf. CLBA, 10th edition, 2022, II.C.5.4. There it is important that an effect associated in the patent with the range is plausible or plausibly demonstrated across the whole breadth of the claimed range (leaving aside issues of proof of plausibility, the subject of current referral G2/21). Otherwise the claimed invention would be insufficiently disclosed, because the effect is not plausible across the whole breadth of the range.

In claimed inventions that do not involve a range of parameter values or compositions basing an argument of insufficiency on this approach is inappropriate and can be rejected offhand for that reason. This is especially so where, as in the present case, an invention is directed at a broadly defined concept expressed in terms of generic structural or functional features of an apparatus or of a method. There it normally suffices to provide a single detailed example or embodiment to illustrate how this concept can be put into practice, cf. CLBA, II.5.2., in such a way that the underlying principles can be understood by the relevant skilled person and they can reproduce the claimed invention using their common general knowledge without undue burden, CLBA, II.4.1. It is thus not enough to demonstrate insufficiency to conceive of an example falling within the terms of the claim that does not work because it does not achieve the claimed effect fully or at all. Such an example does not prove that the claimed concept does not work; rather it reflects the limitations that are inherent in any technological endeavour and which may provide the scope for future (inventive) development. To successively argue insufficiency in a case such as this a very high burden of proof applies: the party must demonstrate through cogent argument based on the underlying principles, if necessary supported by evidence, that the claimed concept does not work, because it does not achieve the desired effect in any measure or indeed is counter to the laws of nature. Or they must demonstrate that the disclosure lacks information on an important aspect of the claimed invention, without which the skilled person cannot realize the claimed invention without undue burden. The appellant has failed to present any such arguments in the present case.

3.7 The Board thus concludes that the invention is sufficiently disclosed, as held by the opposition division.