T 0680/94 16-04-1996

Reasons for the Decision

1. The appeal complies with the requirements of Articles 106 to 108 and Rules 1(1) and 64 EPC. It is therefore admissible.

2. Main request

Document D1 discloses, with particular reference to Figures 1 to 7, a mechanism for supporting and extending a high-lift device, in particular a wing leading edge flap. The flap is mounted on a plurality of carrier beams which have an inverted generally U-shaped cross- section. The carrier beams are supported by rollers which extend between respective pairs of wing ribs and engage upper and lower surfaces of the beams. Each carrier beam is provided with a gear rack disposed between the open arms of its U-shaped cross-section, the gear rack meshing with the teeth of a pinion gear driven by a rotary actuator in the form of a reduction drive driven by a remote power unit. The actuator is attached to one of the wing ribs with its output shaft supported by bearing assemblies located in respective bores in the wing ribs and the pinion gear is splined to the output shaft.

Document D1 is referred to in the description of the present patent specification and forms the basis of the preamble of claim 1. In the description it is commented that in this prior art the pinion gear is only installed simultaneously with the actuator engaging splines on the actuator shaft. Thus, when the actuator is withdrawn for any purpose, the pinion is automatically disconnected from its engagement with the gear rack. Due to the tight interface between the pinion and the actuator necessary in this method of assembly the installation of the pinion or its removal may be difficult, particularly for reasons of access or manoeuvrability in the very limited space available within the wing structure. Furthermore the pinion may be subject to damage, contamination or misplacement. In the case of the carrier beam the use of "drilled to size" holes in the beam and gear rack is inpracticable for numerous reasons, not least of which is the difficulty of achieving accurate positioning of the gear rack to achieve the correct tooth pitch datum, and more particularly the pitch circle radius in the case of an arcuate carrier beam arrangement. To achieve an accurate and controlled meshing relationship between the single-piece gear rack and the pinion, it would be preferable that, on the one hand, means were provided to ensure that the rack is correctly jigged and located to the carrier beam prior to its assembly to the wing and, on the other, to provide an assembly in which the pinion gear is rotatably mounted to the wing structure independently of the actuator so that the track is installed into engagement with the pinion and maintained as such even when the actuator and/or the high speed shaft system is dismantled for whatever purpose.

After these comments it is stated that the object of the invention is "to overcome these shortcomings, and to enable achievement of the desiderata set out above."

It can be seen that the above comments are concerned with two related but distinct aspects of the mechanism. The first is the connection of the gear rack to the carrier beam, the second the mounting of the pinion gear with respect to the wing ribs. Claim 1 is however silent as to any features concerned with the first aspect. The relevant features appear in fact in dependent claim 4. The features specified in the characterising clause of claim 1 are concerned only with the second aspect.

At the oral proceedings before the Board, and in the course of the opposition proceedings, the appellants argued that the particular form of the bearing housing assemblies disclosed in the patent specification, which are attached by bolts or the like to the inner surface of the respective wing rib enabled the position of the pinion gear to be adjusted so as to give the desired accurate meshing between the pinion gear and the gear rack. There is, however, no mention of this whatsoever in the patent specification. Furthermore, it does not appear to be inherent in the structure disclosed since, for example, the position of the pinion gear is also determined by the fact that it is splined to the output shaft of the actuator and the position of the later is in turn determined by the bore in the wing rib to which it is attached. In the light of this the Board is of the opinion that the technical problem of which account has to be taken when assessing inventive step is limited to the second of the aspects mentioned above, namely the provision of means enabling the actuator to be removed with the pinion gear still in place.

Particularly in view of the comments made in the patent specification with respect to document D1 the Board is of the opinion that the skilled person would understand the feature of claim 1 that the pinion gear is supported for rotation "independently of the actuator" as meaning that the pinion gear is directly carried by the bearing assemblies and not via the intermediary of a part (the output shaft of the reduction drive) driven by a remote "actuator" (i.e. the power unit), as is the case in document D1. This feature therefore represents a genuine distinction from the state of the art.

The appellants sought to establish a further important distinction in the fact that claim 1 requires the use of "bearing housing assemblies" which according to their interpretation of the claim are located "between the wing ribs" and which therefore are clearly different to the bearing assemblies used in document D1, which are located in respective bores in the wing ribs. As a plain matter of language it is however evident that the term "between said wing ribs" refers to the position in which the pinion gear is supported by the pair of bearing housing assemblies and not to the position of these assemblies themselves. The latter is left completely open by the claim as indeed is the form of the assemblies and the way in which they are mounted with respect to the wing ribs. In general terms, as pointed out in the contested decision, the outer bearing ring or sleeve of a rolling bearing can be considered as comprising a "housing".

Thus the Board shares the view expressed in the contested decision that the rolling bearings disclosed in document D1, which are mounted via their outer bearing sleeves in respective bores in the wing ribs, constitute "bearing housing assemblies" within the meaning of claim 1. In this respect it is to be noted that the "bearing housing assemblies" actually disclosed in the patent specification also comprise nothing more than inner and outer bearing sleeves with rolling elements disposed between them, the outer sleeve being formed with a flange via which it is attached to the wing rib. Furthermore, it is apparent in document D1 that the pinion gear is mounted (via the splines on the output shaft of the actuator) "fast in rotation with the inner bearing sleeves of the bearing assemblies".

It is not in dispute that the bearings disclosed in document D1 are not "self-aligning". It is, however, equally not in dispute that the use of such bearings is wholly conventional in the relevant field as the wings of aircraft undergo considerable flexing in operation. Thus the appellants did not seek to justify the inventive step of the claimed subject-matter by reference to this feature of claim 1.

Having regard to the above it is apparent that the question of inventive step will be determined by whether it was an obvious measure to provide for support of the pinion gear independently of the actuator.

The respondents have relied in this respect on documents D12 to D18 relating to the wing leading edge flap support and extension mechanism of the Boeing 747 aircraft. The fact that this aircraft belonged to the state of the art has never been called into question. Documents D12 to D18 disclose an arrangement where the flap is carried by a number of pivotal linkages. The main arm of each linkage is pivotally attached to the wing via a respective torque tube to which it is splined and which is supported at either end by rolling bearings each located in a respective bore of a wing rib. A rotary actuator is attached to one of the wing ribs and has an output shaft with splines which engage a splined inner end of the torque tube.

Now, the appellants argue that documents D12 to D18 are in no way concerned with the mounting of a pinion gear or with the meshing of such a gear with a gear rack so that the skilled person dealing with these problems would find nothing here which would be of relevance to him. In the opinion of the Board that argument relies partly on an incorrect evaluation of what is actually achieved by the measures of claim 1, which is not, as explained above, more accurate meshing between the pinion gear and the gear rack, and partly on an over- restricted view of the power of abstraction of the skilled person. It is the opinion of the Board that the latter would certainly be able to see in the known arrangement of the Boeing 747 aircraft means by which it is possible to arrange for the actuator to be removable while leaving all other parts of the support and extension mechanism in place, and it is only to this aspect to the technical problems mentioned in the patent specification that the subject-matter of claim 1 provides a solution. Thus the Board comes to the conclusion that independently supporting the pinion gear of the mechanism shown in document D1 by means of bearing assemblies, in the manner the torque tube is supported as shown in documents D12 to D18, is a measure which was obvious for the skilled person, and as a consequence the subject-matter of granted claim 1 lacks inventive step.

3. Auxiliary request

It belongs to the established jurisprudence of the Boards of Appeal that the admission of amended claims into appeal proceedings, particularly when the amendments are first submitted at oral proceedings, is at the discretion of the Boards, see for example T 95/83 (OJ EPO 1985, 75) and T 153/85 (OJ EPO 1988, 1). The factors which need to be taken into account when exercising this discretion include whether there is some clear justification for the late submission of the amendment and whether the amended documents are clearly allowable, firstly in the sense of conforming with the formal requirements of the EPC and secondly in the sense of having at least a reasonable prospect of removing the outstanding substantive objections against the documents previously on file.

In the present case the appellants sought to justify the introduction into claim 1 of the auxiliary request of the feature that the bearing housing assemblies are mounted upon the inner faces of each respective rib by arguing that this was a mere clarification of the feature of granted claim 1 that these assemblies were provided "between said wing ribs". As however explained above the latter feature does not in fact appear in granted claim 1, which contained no information about the way the bearing housing assemblies are mounted which was capable of "clarification". Furthermore, the relevant feature added to the claim is not to be found in any dependent claims as granted and is mentioned only very briefly in the description without any indication that it might be associated with specific technical advantages. Thus on the basis of the patent specification the respondent could have no reason to suspect that the relevant feature might be added to claim 1.

It is true, as also argued by the appellants, that in the course of the opposition proceedings they had made reference to the advantageous nature of the mounting of the bearing housing assemblies as disclosed in the patent specification in allowing adjustment of the position of the pinion gear. However, the Opposition Division had in the contested decision clearly explained its view, which for the reasons given above is shared by the Board, that the bearing housing assemblies as defined in granted claim 1 were not distinguished from what was disclosed in document D1. In their statement of grounds of appeal the appellants did not however refer to this issue. Furthermore, they made no written response to the annex to the summons to oral proceedings from which it was apparent that the Board in this respect followed the opinion expressed in the contested decision. On this basis it becomes clear that the relevant amendment made to claim 1 was not presaged by the manner in which the appellants had conducted their appeal up to the date of the oral proceedings. Thus it would have been unfair on the respondents to have admitted the auxiliary request of the appellants at this late stage.

As for the substantive issues involved it must also be noted that the advantage claimed for the mounting of the bearing housing assemblies on the inner surfaces of the wing ribs, namely allowing adjustment of the position of the pinion gear, is nowhere mentioned in the patent specification and on the face of what is actually disclosed is at least questionable. It is therefore difficult to see how this claimed advantage could be successfully prayed in aid for the inventive step of the subject-matter of the auxiliary request.

The Board therefore comes to the conclusion that the auxiliary request of the appellants is inadmissible and accordingly rejects it. In these circumstances there is no need to consider whether the amendment made to the claim concerning the relationship between the pinon gear and the actuator constitutes an abuse of the procedure, as was also argued by the respondents.