T 0483/19 16-03-2022

I. The European patent No. 2 826 708 was revoked by the decision of the Opposition Division posted on 21 December 2018. Against this decision an appeal was lodged by the Patentee in due form and in due time pursuant to Article 108 EPC.

II. The following documents are cited in this decision:

EP-A (designating the published patent application of the contested patent);

EP-B (designating the publication of the contested patent);

D3 (US 2012/0269644 A1);

D4 (EP 2 484 895 A1).

III. Oral proceedings were held on 16 March 2022. The Appellant (Patent Proprietor) requested that the decision under appeal be set aside and the patent be maintained in amended form on the basis of auxiliary 3 filed with the statement of the grounds of appeal. The Appellant withdrew all other requests on file.

The Respondents I and II (Opponents 2 and 1 respectively) requested that the appeal be dismissed.

IV. Claim 1 of auxiliary request 3 (sole request) reads as follows:

"A rotor blade assembly (100) for a wind turbine (10), the rotor blade assembly comprising:

A rotor blade (16) having exterior surfaces defining a pressure side (22), a suction side (24), a leading edge (26), and a trailing edge (28) each extending between a tip (32) and a root (34), the rotor blade (16) further defining a span (44) and a chord (42); and

a surface feature (102) configured to be installed on an exterior surface defining a pressure side (22) or a suction side (24) of the rotor blade (16),

the surface feature being flexible and having an exterior mounting surface (122), at least a portion of the exterior mounting surface (122) having a contour in an uninstalled state different from a contour of the exterior surface of the rotor blade (16) at a mount location of the surface feature on the rotor blade (16),

a plurality of attachment features (130) connecting the surface feature to the rotor blade (16),

the plurality of attachment features (130) comprising a first attachment feature proximate a perimeter of the surface feature and a second attachment feature spaced from the perimeter of the surface feature relative to the first attachment feature, and

a seal member (160) surrounding at least a portion of the perimeter of the surface feature (102) and the plurality of attachment features (130),

the seal member (160) contacting and providing a transition between the exterior surface (102) and the surface feature (102)".

V. The Appellant's (Patentee) arguments may be summarized as follows:

The objection of the Respondents alleging that claim 1 includes subject-matter (i.e. as implied by the feature "a seal member (160) surrounding at least a portion of the perimeter of the surface feature (102) and the plurality of attachment features (130)", hereinafter designated as feature (i)) extending beyond the content of the application as filed should not be admitted into the appeal proceedings. This objection is late filed since it was raised only during the oral proceedings before the Board of Appeal and also not in response to any new arguments or submissions of the Patentee.

The subject-matter of claim 1 does not extend beyond the content of the application as filed, for the feature reading "the surface feature being flexible" (hereinafter designated as feature (ii)) is derivable from EP-A (see e.g. paragraph [0024}), "flexible" implying both a material being apt for bending as well as an elastic material.

The patent specification discloses the invention in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art. In effect, there is no contradiction between dependent claims 8 and 9 (depending inter alia on claim 8), given that specific mounting locations on the wing (see e.g. D4, figure 3) may include both a convex and a convex shape, e.g. in wing regions including points where a transition from a convexly shaped segment to a concavely shaped segment (as seen in a chordwise (vertical) wing section) occurs. Further, different mounting locations on the rotor blade may have a "concave" or a "convex" shape.

Secondly, the skilled person based on common technical knowledge would naturally interpret the terms "concave" and "convex" (see e.g. claims 8 and 9) as defining the shape of a surface resulting from observing it in frontal and direct view, thus frontally and directly exposing the surface to the observer's view. Consequently, the skilled person would understand that (based on this definition) the exterior mounting surface 122 (of the surface feature 102) as shown for example in figures 3 and 7 is concave whereas the exterior surface of the rotor blade is convex, in accordance with the wording of claim 9.

The skilled person would therefore conclude that the definition of the terms "convex" and "concave" as resulting from paragraph [0027] of EP-B (in conjunction with the figures) is obviously erroneous and incorrect (as both the exterior mounting surface 122 and the exterior surface are defined as being "convex" in figure 3 and 7). Nonetheless, this apparent contradiction would not prevent the skilled person from correctly understanding the invention and from putting it into effect, as detailed above.

The subject-matter of claim 1 is new over D3 since at least features (iii) (i.e. "the plurality of attachment features (130) comprising a first attachment feature proximate a perimeter of the surface feature and a second attachment feature spaced from the perimeter of the surface feature relative to the first attachment feature") and (i) (i.e. "a seal member (160) surrounding at least a portion of the perimeter of the surface feature (102) and the plurality of attachment features (130)") are not disclosed in D3.

The Respondents' objection based on lack of inventive step of the claimed subject-matter over D4 should not be admitted into the appeal proceedings as it was raised only during oral proceedings before the Board and it was not submitted in response to any new arguments or filings of the Patentee.

The subject-matter of claim 1 involves an inventive step over D3, for feature (i) in conjunction with the further claimed features would not be obvious for the skilled person. In particular, in D3 (see paragraph [0016], [0031], figure 2 and 7) two sealing members are already provided for protecting the attachment features (or mounting bands) against humidity and adverse weather conditions on the outer perimeter of the surface feature. Therefore, the skilled person would not be incentivized or motivated to arrange further sealing members also on the inner side portion of the surface feature to protect the mounting bands, as there would be no necessity to do this.

VI. The Respondents' (Opponents 1 and 2) arguments may be summarized as follows:

The subject-matter of claim 1 extends beyond the content of the application as originally filed (EP-A), for feature (i) (i.e. "a seal member (160) surrounding at least a portion of the perimeter of the surface feature (102) and the plurality of attachment features (130)") was not disclosed in EP-A, and this objection should be admitted into the appeal proceedings. Indeed, the Appellant's construction of this feature was submitted only during oral proceedings before the Board of Appeal, the Appellant alleging feature (i) implying a single seal member surrounding (at least a portion) of the perimeter of the surface feature and at the same time the entirety of the plurality of the attachment features of said surface feature. Consideration for the Respondents' right to be heard therefore justifies the admission of said objection, which is in response to this surprising interpretation of feature (i) by the Appellant.

The subject-matter of claim 1 extends beyond the content of the application as filed, for feature (ii) (i.e. "the surface feature being flexible") is not derivable from EP-A (see e.g. paragraph [0024}), "flexible" merely implying a material being apt for bending but certainly not an elastic material, as the Appellant contends.

The patent specification does not disclose the invention in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art.

The dependence of claim 9 on claim 8 (depending on claim 1) requires that the exterior surface (of the rotor blade) be at the same time concave and convex. This is clearly impossible for the skilled person to implement, given that claim 1 specifies only one mounting location, contrary to the Appellant's view. Also, there is no disclosure in the patent specification (EP-B) that at a specific mounting location the exterior surface (of the rotor blade) may be both convex and concave, as contended by the Appellant. This evidently entails that the invention as defined by the set of claims is not sufficiently disclosed.

In addition, the scope of protection of claim 1 is completely unclear, for paragraph [0027] in EP-B gives an unambiguous and consistent definition of the terms "convex" and "concave" based on the figures, such that e.g. in figure 3 and 7 both the exterior mounting surface 122 and the exterior surface (of the rotor blade) are defined as "convex", contrary to the Appellant's definition. The unambiguous and consistent definition according to paragraph [0027] implies that the configuration of the exterior mounting surface and of the exterior surface as implied by claim 9 (the exterior mounting surface and the exterior surface being respectively "concave" and "convex") is not illustrated in any of the figures disclosed in EP-B, particularly not in figures 3 and 7 (as contended by the Appellant).

Moreover, for the specific configuration (mentioned in paragraph [0027]) according to claim 9 no further indications or details are given in the description of EP-B concerning any technical effects possibly resulting or obtained by this configuration. Consequently, the skilled person would not be able to infer from EP-B which specific configuration (or embodiment) is protected by claim 1, given none of the specific configurations (or embodiments) according to the figures (in particular figures 3, 5 and 7) being explicitly incorporated and included in the set of claims, whereas claim 9 is not supported by the description and the figures. In particular, the skilled person would not be capable of deducing from EP-B, whether protection is sought e.g. for the embodiment shown in figure 3 or according to claim 9.

In conclusion, it ensues that the invention (particularly dependent claim 9) is not sufficiently clearly and completely disclosed for it to be carried out by the skilled person.

The subject-matter of claim 1 is not new over D3, feature (i) (i.e. "a seal member (160) surrounding at least a portion of the perimeter of the surface feature (102) and the plurality of attachment features (130)") and the further features of claim 1 being known from D3. In particular, feature (i) is derivable from D3, for D3 discloses in figure 2 and 7 a sealing member 3 which surrounds at least a portion of the perimeter of the surface feature 1 and surrounding at least a portion (and not the entirety) of the plurality of attachment features 11A, 12A (see D3, [0016], [0033]).

The objection based on lack of inventive step of the subject-matter of claim 1 in view of D4 should be admitted into the appeal proceedings in view of the Appellant's surprising interpretation of feature (i). In addition, admitting D4 into the appeal proceedings would not be incompatible with procedural economy, as D4 was already discussed in relation to the issue of novelty of the subject-matter of claim 1 of the main request.

The subject-matter of claim 1 is not inventive over D3, given that the skilled person would obviously provide a sealing member in the form of a sealing strip 3 also on the inner longitudinal edge of the adhesive layers 2 and mounting bands 11A (see figure 2 and 7), thus sealing also the portion of the adhesive strips 2 which is located (on the exterior surface of the rotor blade) within the interior of the surface feature 1. Thus a better protection of the adhesive layers 2 against humidity and adverse weather conditions would be achieved.

Alternatively, the same result would be obtained by the skilled person by simply closing and sealing both open ends of the surface feature 1 (see D3, figure 7) using appropriate sealing material. Hence, feature (i) in combination with the further claimed features (known from D3) cannot justify an inventive step.