T 0709/22 () of 22.4.2024

Summary of Facts and Submissions

I. The appeal was filed by the opponent 2 against the interlocutory decision of the opposition division finding that, on the basis of the auxiliary request 5, the patent in suit met the requirements of the EPC.

II. Amongst other things, the opposition division decided that the subject-matter of this request was novel against D3.

III. In a communication in preparation for oral proceedings, the Board set out its observations on the relevant issues. Oral proceedings were held on 22 April 2024 in the absence of the party as of right, opponent 1, which had been duly summoned.

IV. The appellant (opponent 2) requests that the decision under appeal be set aside and that the patent be revoked.

The respondent (patent proprietor) requests that the appeal be dismissed (patent maintained according to auxiliary request 5), in the alternative that the patent be maintained in amended form according to one of auxiliary requests 6 to 8, all filed with letter of 23 September 2022.

The party as of right (opponent I) has made neither submissions nor any request in appeal.

V. Claim wording of auxiliary requests 5 to 8

The independent claims of auxiliary request 5 read as follows:

"1. A temporary maintenance enclosure (10) for the maintenance of at least part of a turbine blade, said enclosure comprising four side walls (11, 12, 17, 18) which form a rectangular configuration and which substantially surround the circumference of a blade in need of maintenance; and a roof (15) extending from said side walls towards said blade; wherein said roof comprises an aperture (16) through which said blade is received; and wherein said enclosure comprises a platform (21) which is bounded by each of said side walls and located inside said side walls; and said platform comprises an aperture through which said blade is received; said platform comprising four flanks which are attached to said side walls; and wherein said side walls are collapsible".

"10. A method of maintaining a turbine blade, comprising the steps of:

a. providing a platform on which maintenance of a turbine blade can occur;

b. deploying a temporary maintenance enclosure which is adapted to fit around said platform; said enclosure comprising four side walls which form a rectangular configuration and which bound said platform and substantially surround the circumference of a blade; and a roof extending from said side walls towards said blade;

said roof comprising an aperture through which said blade is received; and

wherein said platform is located inside said side walls and comprises an aperture through which said blade is received; said platform comprising four flanks which are attached to said side walls; and

wherein said side walls are collapsible."

Independent claims 1 and 9 of auxiliary request 6 read as for claims 1 and 10 of auxiliary request 5 except that the following wording is added to the end of the the respective claims: "; and wherein said enclosure is at least partially inflatable".

Independent claim 1 of auxiliary request 7 reads as for claim 1 of auxiliary request 5 except that the last feature "and wherein said side walls are collapsible" is amended to read:

"wherein said platform incorporates a barrier and wherein said side walls and said barrier are collapsible".

Independent claim 9 of auxiliary request 7 reads as for claim 10 of auxiliary request 5 except that the last feature "and wherein said side walls are collapsible" is amended to read: "said platform comprising a barrier and wherein said side walls and said barrier are collapsible".

Independent claim 1 of auxiliary request 8 reads as for claim 1 of auxiliary request 5 except that the following wording is added to the end of the claim:

"and wherein said roof (15) incorporates an inflatable portion, a seal about said aperture and a flexible sheath (19) extending from said aperture to said inflatable portion".

Independent claim 9 of auxiliary request 8 reads as for claim 1 of auxiliary request 5 except that the following wording is added to the end of the claim:

"and wherein said roof comprises an inflatable portion and a seal about said aperture; and

c. securing a flexible sheath, which extends from the aperture in said roof, to said turbine blade".

VI. In the present decision, reference is made to the following documents:

D1: DE 102010011365 A1

D3: EP 2957538 A1

D6: ES 1072052 U

VII. The appellant-opponent's arguments can be summarised as follows:

The subject matter of claim 1 of auxiliary request 5 (as maintained) lacks novelty with respect to D3. The subject matter of the independent claims of auxiliary requests 6 to 8 lacks inventive step starting from D3 in combination with D1. Claim 1 of auxiliary request 5 is unclear and the same reasoning applies to auxiliary request 8.

VIII. The respondent-proprietor's arguments can be summarised as follows:

The subject matter of claim 1 of auxiliary request 5 is new with respect to D3. Auxiliary requests 6 to 8 involve an inventive step starting from D3 in combination with D1. Moreover, claim 1 of all requests is clear.

Reasons for the Decision

1. The appeal is admissible.

2. Introduction

The patent relates to a temporary maintenance enclosure for wind turbine blades and a method of maintaining turbine blades (see published patent specification, paragraphs [0001], [0023] and the independent claims of all requests). A central idea of the invention is to provide a temporary platform which has an aperture for receiving a wind turbine blade and side walls and a roof so that work can be carried out in poor weather (see paragraphs [0010] and [0011]).

3. Auxiliary request 5, claim 1, novelty with respect to D3

3.1 The opposition division found (see impugned decision, reasons 27) that D3 did not disclose the claim features of the platform being:

- bounded by each of the side walls,

- located inside the side walls,

- and its four flanks being attached to the side walls.

The appellant-opponent 2 challenged this finding, arguing the D3 was prejudicial to novelty of claim 1. The Board agrees.

3.2 D3 (see abstract and figure 2) discloses a temporary maintenance enclosure for maintaining a turbine blade. As figure 2 shows, the enclosure has four side walls, referred to as laminar elements, arranged in a rectangle and a roof extending from the side walls towards a blade to be maintained, which passes through an aperture in the roof, so the walls substantially surround the circumference of a blade and the roof (15) extends from the side walls towards the blade.

3.3 The roof and side walls protect a lifting platform (see paragraph [0010]), so its maintenance enclosure comprises a platform. Contrary to how the respondent-proprietor has argued, D3 discloses information about the platform and how it interacts with the rest of the disclosure: Paragraph [0019] explains that the platform remains around the blade awaiting [maintenance] and moves along it, so the platform is not a U shaped platform that engages part of the blade from the side as mentioned in D3 as being known in the prior art (cf. D3, paragraph [0007] and D6, figure 1). Rather, the platform of D3's invention extends around the blade and thus can but comprise an aperture through which the blade is received.

3.4 In the Board's view, D3 also discloses the claim feature of the platform being bounded by the side walls. The word bounded is a cognate of bound (see Oxford English Dictionary online (OED), definition 2a), which means: To form the boundary of. Thus the claim feature requires no more than that the side walls coincide with the outer limits of the platform. In this regard, the Board notes that, rather than the skilled person approaching the claim with a strict literalist approach, they approach claim wording reasonably, with a practical mindset. Regarding the feature of the platform being bounded by the side walls, they read (see published patent specification, paragraph [0034]) that this allows operators to move around and effectively service the blade [protected from the weather by the walls]. Thus, they will not understand that bounded here might mean that where the claimed collapsible wall meets the platform there must be a seamless transition between the two or that the walls must touch the platform. In other words, a reasonable reading of the claim is that small gaps between the flexible wall and the platform are not excluded by the term bounded.

3.5 D3 (see paragraph [0021]) discloses that vertical posts are attached to each of the four corners of the platform. Reading this part of D3's description with the same practical mindset as the skilled person reads the claim, the vertical posts are explicitly attached to the four points at which the sides of the platform meet, and not at undefined points somewhere near the edge of the platform as the respondent-proprietor would have it. Since these posts also constitute the corners of the four walls (see figure 2), the platform extends just as far as the walls in the horizontal direction, so it is bounded by the side walls, whether or not there might be a small gap in the vertical direction between the bottom of the walls and the platform. Moreover, with the outer corners of the walls and platform coinciding, the platform is located inside the side walls as claimed. Indeed, since, just as with the patent, the purpose of D3's enclosure, with its four walls and a roof is to protect workers on the platform from the weather (see paragraph [0017]), the platform can but be bounded by and located within the side walls.

3.6 Turning now to the feature of the platform having four flanks which are attached to the side walls, since D3's platform has four corners and is arranged around the blade to be serviced, it must have four lateral sides. In other words four flanks (cf. OED, definition of flank, II.5). In the Board's view, these flanks are attached to the side walls: As explained in paragraph [0021], the vertical posts are attached to each corner of the platform and a horizontal beam at the base of each post, which can be seen in figure 2 to form a kind of foot, fits into the platform structure, rather than the horizontal beam merely sliding on a rail, being attached to a barrier on the platform or otherwise accommodated above the platform as the respondent-opponent has postulated.

This is all the more true since the end of paragraph [0021] explains that fixing methods are used to carry out this fitting, so the horizontal pieces are fixed to the platform rather than merely slidably engaging with it. Moreover, the walls (laminar elements 2) are attached to the frame, which includes the vertical posts, by means of clasps or clamps for example. The Board notes that the claim does not require a direct connection between the side walls and the flanks, they must merely be connected. So irrespective of whether the frame is considered to be part of the walls, part of the platform or a separate entity, the platform's four flanks are attached (directly or indirectly) to the side walls by means of the frame.

Finally, as explained in paragraph [0023], the walls (lateral laminar elements) are made of flexible canvas, so they are collapsible. Therefore, D3 takes away novelty of claim 1. For these reasons, auxiliary request 5 fails.

4. Examination of inventive step of auxiliary requests 6, 7 and 8

4.1 The opposition division maintained the patent amended in accordance with a higher ranked request (auxiliary request 5), finding its subject matter to be new with respect to D3, amongst other things. The division therefore did not consider auxiliary requests 6 to 8 in its decision. Nor did the appellant-opponent comment on these requests in written proceedings. In the light of this, the Board finds it appropriate to examine novelty/inventive step of these requests within the context of its finding that D3 takes away novelty of the higher ranking request and the factual and evidentiary framework set out in the opposition proceedings for their corresponding features. The parties agreed with this approach. The appellant-opponent 2 formulated inventive step arguments for all the requests starting from D3 combined with D1.

4.2 The independent claim 1 of auxiliary requests 6, 7 and 8 contain the features of claim 1 of auxiliary request 5 whilst introducing the features of granted claims 2 (partly inflatable), 9 (collapsible barrier) and 4 (sheath). The independent method claims of the respective requests have broadly corresponding amendments. In its notice of opposition (see pages 9 and 10), the appellant opponent 2 cited D1, amongst other documents, as relevant to granted claims 2, 9 and 4. Therefore, the appellant-opponent 2's inventive step objections starting from D3 in combination with D1 lies within the factual and evidentiary framework within which the Board can examine these requests, see above.

4.3 Auxiliary request 6, claim 1, inventive step starting from D3 with D1

4.3.1 Compared to auxiliary request 5, claim 1 of auxiliary request 6 adds the feature of the enclosure being at least partially inflatable. It is not disputed that D3's enclosure is not partially inflatable. The walls and roof are merely said to be of flexible laminate material, such as canvas (see for example the abstract and paragraphs [0012] and [0023]).

4.3.2 The Board examines inventive step using the problem solution approach which normally starts from the technical effect of a distinguishing feature as set out in the patent. In the present case, the patent explains (see published specification, paragraph [0014]) that having the enclosure partially inflatable makes it quick and easy to employ and light weight.

4.3.3 Therefore, the objective technical problem can be formulated as how to improve the enclosure of D3 to make it quick and easy to employ and lighter in weight. In the Board's view the skilled person would be aware of D1 because it also relates to a weather protected platform for servicing wind turbines. Central to this disclosure is a roof with inflatable elements (see abstract and claim 1). The skilled person, a mechanical engineer with experience in maintenance enclosures would immediately see that its inflatable roof elements will be quick to employ, because they need only be inflated in much the same way as a mobile children's bouncy castle is (see D1, paragraph [0010]). Moreover, being air filled, the inflatable elements will provide a light-weight structure. In solving the objective technical problem, the skilled person would therefore, as a matter of obviousness, incorporate inflatable elements into at least the roof of D3's enclosure and thereby arrive at the features of claim 1. In this regard, the respondent-proprietor's argument that D1 only teaches to provide an inflatable roof and so the enclosure resulting from a combination of D3 and D1 would, at most have an inflatable roof but not inflatable side walls is irrelevant to the question of inventive step of claim 1. This is because, in its broadest sense, the claim requires no more than that the enclosure is [...] partially inflatable, without specifying which part. Thus, the obvious combination of the teachings of D3 and D1, would result in an enclosure with an inflatable roof that falls within the ambit of claim 1. Therefore, claim 1 lacks inventive step, Article 56 EPC and auxiliary request 6 must fail.

4.4 Auxiliary request 7, claim 1, inventive step starting from D3 with D1

4.4.1 Compared to auxiliary request 5, claim 1 of auxiliary request 7 adds the feature of the platform comprising a collapsible barrier. Although D3 is silent as to any barrier surrounding the aperture in the middle of the platform through which the turbine blade passes, the Board holds that it is implicit that one will be present. In this regard, the Board notes that the platform (see paragraph [0019]) is suspended from cables that hoist it into place around a wind turbine blade, usually tens of metres above the base of the tower. For ensuring the safety of those working on the platform at such heights, some kind of a barrier must be provided around its central aperture. According to the patent (see published specification, paragraph [0022], the technical effect of making the barrier collapsible is to reduce the size of the platform when not in use. Therefore, the objective technical problem can be formulated as how to implement a barrier in D3's platform such that the platform is compact when not in use.

4.4.2 In implementing such a barrier, the skilled person would be aware of D1 which discloses a railing which acts as a barrier (see D1, paragraph [0019] with figure 1, reference 3). Although that barrier is at the outer edge of the platform, the Board holds that the skilled person would implement a barrier at the platform's inner edge in just the same way, namely as a railing. This leaves only the question as to the obviousness of making such a railing collapsible. In the Board's view, making railings collapsible when they are only required temporarily is so well known to the skilled person that it behoves no evidence to prove this to be so.

The respondent-proprietor has argued that, in view of the great height at which such maintenance enclosures operate, it would however be counter-intuitive to use a collapsible barrier in this situation and so the skilled person would avoid doing so when combining the teachings of D3 and D1. The Board disagrees.

4.4.3 D3 discloses that the outer walls of its enclosure are collapsible, moreover, these are supported on a metal frame formed of beams which can be fitted together using connectors (see paragraph [0020]), so these are likewise implicitly collapsible when not in use. In other words, the skilled person would recognise that all the enclosure elements located on D3's platform are collapsible. Therefore, starting from D3 and faced with the objective technical problem (compact platform when not in use), it would not be counter intuitive for the skilled person to apply the generally known idea of making a barrier collapsible. They would therefore apply this idea to the railing as known from D1, when combining D3 and D1. In so doing they would arrive at the subject matter of claim 1, as a matter of obviousness. Therefore, auxiliary request 7 fails for lack of inventive step, Article 56 EPC.

4.5 Auxiliary request 8, claim 1, inventive step starting from D3 with D1

4.5.1 Compared to claim 1 of auxiliary request 5, this claim adds the features of the roof incorporating an inflatable portion, a seal about the [roof] aperture

and a flexible sheath extending from the aperture to the inflatable portion. It is not disputed that D3 does not disclose an inflatable portion, therefore, at least for this reason, the claimed subject matter is new with respect to D3.

4.5.2 D3 discloses a seal as claimed (see paragraph [0025] and the enlarged detail in figure 2): It is a closing accessory that comprises an elastic strip 4 and a row of suction pads 5. The whole forms a seal about the aperture which prevents rain water from reaching the enclosed platform. As has already been explained in the discussion of auxiliary request 6, D1 discloses a roof with an inflatable portion and it would be obvious to combine the teachings of D3 and D1 to arrive at a roof with an inflatable portion. It may be argued as does the appellant-opponent that, in so doing, it would be obvious for the skilled person to keep D3's seal about the roof aperture. The question of inventive step then boils down to whether the combined teachings of D3 and D1 would result in an elastic sheath extending from the aperture to the inflatable portion. In the Board's view they would not.

4.5.3 A sheath is a case or covering into which a blade is thrust when not in use, usually close-fitting and conforming to the shape of the blade, esp. of a sword, dagger, knife, etc and its transferred uses (see OED definitions 1a and 1b).The claim defines a sheath that is part of a roof and which extends between an aperture that receives the elongate blade of a wind turbine and an inflatable portion of the roof. In this context, the Board reads the word sheath in its transferred use as denoting a covering for the wind-turbine blade that extends along its length and conforms to its shape. The claim also defines the sheath to be flexible. In the Board's view, the syntax of this part of the claim is clear in itself and defines a logical relationship between the sheath and the other parts of the roof. Therefore, the fact that paragraph [0039] appears to paint a different picture of the sheath plays no role in interpreting the claim.

4.5.4 The appellant-opponent has argued that D3's elastic strip 4 is a sheath, or that the flexible roof 3 around the elastic strip 4, best seen in figure 2 would be a sheath. The Board does not find this convincing. In the Board's view, D3's elastic strip 4 is not a sheath as it understands the term, firstly because it is not a covering for the blade extending along its length. Rather, it is a narrow strip extending breadth-wise about the blade only to a sufficient depth to provide a seal. Secondly, as seen in figure 2, although it extends from the highest point on the roof - that is the aperture - it does so towards the row of suction pads 5, rather than towards another part of the roof, as the claimed sheath does. Therefore, it is not a sheath as claimed. Nor does the Board see the upper part 3 of D3's roof as being a sheath. This part extends from the aperture, but it is a shallowly pitched area overlying the platform underneath and essentially extending transversely from the blade, rather than forming an elongate covering for the blade, as a sheath would in the Board's understanding of the term.

4.5.5 Nor does the Board consider D1 to disclose a sheath. There (see paragraph [0027] with figure 3), a turbine blade 1 is tightly enclosed by inflatable roof portions 6. A zipped parting between these forms the roof aperture. Therefore, there is no flexible element extending from the roof aperture to an inflatable portion, let alone one that forms an elongate covering as the Board interprets the claimed sheath to be.

4.5.6 Since neither D3 nor D1 discloses a sheath extending from the [roof] aperture, their combined teaching would not lead the skilled person to a temporary maintenance enclosure having this feature. The Board concludes that the subject matter of claim 1 involves an inventive step with respect to D3 in combination with D1.

5. Auxiliary request 8, claim 9, inventive step starting from D3 with D1

Claim 9 has features largely corresponding to claim 1 in terms of method steps. The appellant-opponent 2 considered its objections to claim 1 likewise applied to claim 9. Therefore, the Board's conclusion with respect to claim 1 of this request also apply to claim 9 (involves an inventive step).

6. Auxiliary request 8, claim 1, clarity

6.1 Compared to auxiliary request 5, the amendments to claim 1 of auxiliary request 8 only add features from a granted claim. In accordance with G 3/14, the Board does not have the power to examine clarity of such an amendment (see reasons, point 85 and the order). However, the claim also has the same amendments as were made to auxiliary request 5, which add features from the description and to which the appellant-opponent 2 raised objections in its appeal grounds (see page 6, section 4), namely with regard to the features it referred to as M2 (enclosure comprising four side walls) and M8 (platform comprising four flanks which are attached to the side walls).

6.2 At the oral proceedings before the Board, after a discussion, the appellant opponent 2 relied on its written submissions in its appeal grounds with regard to clarity aspects of these amendments. In its communication in preparation for oral proceedings (see sections 2, 4 and 5), the Board commented on how it interpreted the claim features M2 and M8 and, based thereon gave its preliminary opinion that the appellant-opponent's clarity objection for auxiliary request 5 was moot. The Board wrote the following:

"2. Interpretation of the feature M2: enclosure comprising four side walls (all independent claims of all requests)

2.1 According to established jurisprudence (see Case Law of the Boards of Appeal, 10th edition, 2022 (CLBA), II.A. 6.1 and II.A.6.3.4), the skilled person construes the claim with a mind willing to understand. In so doing they interpret features giving terms their usual meaning. Moreover (see for example T1018/02, reasons 6.1.1 and T0369/01, reasons 2.3), although a claim must not be interpreted in a way which is illogical or does not make sense, the description may not be used to give a different meaning to a claim feature which in itself impart a clear, credible technical teaching to the skilled [person].

2.2 In the present case, the independent claims have the feature: [...] said enclosure comprising four side walls which form a rectangular configuration [...]. In the Board's view, the skilled person would understand the wording an enclosure comprising four side walls, even when read in isolation, to mean one having exactly four side walls, the enclosure possibly comprising other components than side walls. They would not interpret it to mean that the number of side walls was not limited to four and consequently the enclosure could comprised more than four side walls, as the appellant-opponent 2 argues (see its appeal grounds page 3). Moreover, the Board's interpretation (exactly four) is confirmed by reading the whole feature, since the side walls form a rectangular configuration. The usual meaning of rectangle, see Oxford English Dictionary online (OED) is: A plane figure with four straight sides and four right angles, opposite sides being parallel and equal in length; esp. one in which adjacent sides are unequal, as contrasted with a square. Later also more generally: a thing having the shape of a rectangle. Its conjugate rectangular, meaning: Shaped like a rectangle; having four sides and four right angles. Therefore, claim I unequivocally defines an enclosure with exactly four side walls which meet at right angled corners, rather than it encompassing polygonal enclosures with more than four straight sides and corners at different angles. For this reason the skilled person would not look to the description to find a different interpretation for the claim.

2.3 In any case, the Board considers that the embodiments explained in the description are consistent with what is claimed (see for example paragraph [0031]: In the preferred embodiment the enclosure comprises four side walls which form a square and or rectangle configuration around the blade [...]. The fact that the next sentence states that any number of side walls could be used to the same effect does not negate the preceding description of the preferred embodiment. At most, in the Board's view, the latter sentence only comments on the technical effect achieved by using a rectangular walled structure with four sides or one with a different number of side walls.

2.4 Nor would the skilled person derive anything different from the drawings. They both show a structure with four side-walls 11, 12, 17, 18 which, in cross section, are straight and which meet at essentially right angled corners, to the extent of what is practicably feasible for a large wall structure made of inflatable tube compartments (cf. paragraph [0043])".

[...]

4. Interpretation of the feature M8: said platform comprising four flanks which are attached to said [four] side walls (all independent claims of all requests) The usual meaning of a flank is a side of something (cf. OED: The side or lateral part of anything). In the Board's view, the skilled person would understand the claim to define the platform as having exactly four flanks (sides), each being attached to a respective side wall. This is derived from a purely syntactical logical reading of the feature. Moreover, since the claim also defines (feature M6) that the enclosure comprises a platform which is bounded by each of the side walls, this only goes to confirm that the sides (flanks) are bounded by the four side walls and thus there must be four of them. Were there to be any doubt (the Board sees none) as to how to interpret feature M8 (platform has exactly 4 flanks), a look into the description (see paragraph [0032] with figures 1 and 2) would confirm this interpretation: There, the platform 21 has four straight sections, each being attached to a respective side wall.

5. Auxiliary request 5, claim 1, clarity

In its appeal grounds the appellant-opponent 2 raises a clarity objection against claim 1. Without prejudice to the question of admittance of this objection which was not formulated in the opposition oral proceedings (cf. minutes, page 3), the objection is predicated on interpreting claim 1 as including any number of side walls greater than four (if there are more than four side walls, it would be unclear to which side walls the four flanks are attached). Since, as explained above, the Board interprets the claim differently (it defines exactly four side walls), the objection is moot. It therefore manifestly fails".

6.3 Since the appellant-opponent 2 did not comment on the Board's preliminary opinion in writing and at the oral proceedings relied on its written submissions, the Board sees no reason to deviate from its reasoning or conclusion with regard to clarity of auxiliary request 5, and which likewise apply to the corresponding features of auxiliary request 8. For these reasons, the Board concludes that claim 1 of auxiliary request 8 is clear and meets the requirements of Article 84 EPC.

7. No further objections have been raised or are apparent against the claims according to auxiliary request 8. Moreover, the description has been brought into conformity with these claims as amended. Therefore, the Board finds that the patent and the invention to which it relates now meet the requirements of the EPC. It concludes that the patent can be maintained in this amended form in accordance with Article 101(3) a EPC.

Order

For these reasons it is decided that:

1. The decision under appeal is set aside.

2. The case is remitted to the opposition division with the order to maintain the patent in amended form on the basis of the following documents:

Claims:

Nr 1 - 12 of auxiliary request 8 filed with letter of 23 September 2022,

Description:

pages 2 - 4 as filed on 22 April 2024 at the oral proceedings before the board,

page 5 of the published patent specification,

Drawings:

Figures 1 - 2 of the published patent specification.