T 1238/15 06-06-2019

Main request of the proprietor - patent as granted

1. Article 100(c) EPC

1.1 In its preliminary opinion the Board noted the following:

"This ground of opposition was introduced by the opposition division of its own motion according to Article 114(1) EPC, as can be seen from point 3.2 of the grounds for the impugned decision, in particular the last paragraph of this point.

As explained by the Enlarged Board of Appeal in opinion G 10/91, an opposition division may, in application of Article 114(1) EPC, introduce a ground for opposition not covered by the notice for opposition of its own motion, if such a ground is considered sufficiently relevant.

If an opposition division does introduce such a ground into the proceedings before it, it will of course decide whether such ground prejudices the maintenance of the patent, in the decision that it issues. Since, in the case at hand, the opposition division did decide to introduce said ground for opposition, it became part of the contested decision and, as a result, part of the appeal's legal and factual framework. The Board is therefore both entitled and obliged to consider such ground further, as it is clearly not "a fresh ground for opposition" to be "admitted" in the appeal proceedings (or not), as requested by the patent proprietor.

Moreover, there are no EPC provisions under which a ground for opposition admitted to and examined during the opposition proceedings could be eliminated at the appeal stage nor does the proprietor indeed explicitly rely upon any."

The proprietor did not submit any further comments in reply to this part of the preliminary opinion of the Board. The Board therefore does not see any reason to deviate from its opinion and confirms it hereby.

1.2 As concerns the substance of the corresponding objection, the Board had also noted in its written opinion that it considered the findings under point 3.2 of the impugned decision correct.

Also in regard to this part of the Board's preliminary opinion, the proprietor did not submit further comments. The Board therefore does not see any reason to deviate from its opinion and confirms it hereby, concluding that the subject-matter of at least granted claim 2 extends beyond the content of the application as filed at least for the reasons set out below.

1.3 Indeed and as it was also found by the opposition division and argued by the opponent, the original application (reference is made here and in the following to the published application) only discloses an internal hub transmission with either a first, a second, a third or a fourth ball bearing assembly according to the originally filed claim 1 in combination with either claim 2 or claim 3 or claim 4 or claim 5, all dependent claims being dependent only on claim 1. In the alternative it discloses (according to the description of the preferred embodiment in paragraph 37) a hub transmission with all four ball bearing assemblies in combination, albeit with additional features. In contrast, a hub transmission combining only the first and, for example according to claim 2, the second ball bearing assembly cannot be derived directly and unambiguously from the application as filed.

1.4 The Board thus concludes that the opposition ground under Article 100(c) EPC prejudices maintenance of the patent.

1**(st) auxiliary request

2. Article 123(2) EPC

2.1 Amended claim 2 combines the second, third and fourth ball bearing assemblies of granted claims 2, 3 and 4. Since it depends on claim 1, its resulting subject-matter defines an internal hub transmission comprising inter alia four ball bearing assemblies arranged between the different components of the hub transmission.

2.2 As noted above, such a hub transmission is at least not directly and unambiguously derivable from the originally filed claims 1 to 5, due to the missing back-references in the dependent claims. Contrary to the view of the proprietor, the resulting subject-matter is also not derivable, at least not unambiguously, from paragraph 37 of the application as filed, even when read together with the claims. As pointed out by the opponent, paragraph 37 belongs to the description of the single preferred embodiment disclosed in the application as filed, starting in paragraph 32 and drafted with specific reference to Figures 2, 3 and 6 to 10. This embodiment comprises a number of further features which have not been defined in the claim, for example a plurality of planetary gears as disclosed also in paragraph 33. The claim in contrast only requires a single planetary gear. The resulting subject-matter of claim 2 thus constitutes an intermediate generalisation for which there is no disclosure in the application as filed. The simple fact that the ball bearing assemblies are numbered, according to the claims and the description, cannot be considered to constitute an unambiguous disclosure for the resulting subject-matter.

The Board concludes that the subject-matter of claim 2 extends beyond the content of the application as filed and therefore contravenes Article 123(2) EPC.

2.3 Consequently, maintenance of the patent according to the 1**(st) auxiliary request cannot be allowed.

2**(nd) auxiliary request

3. Article 56 EPC

3.1 The Board applies the problem-solution approach to examine whether the subject-matter of claim 1 involves an inventive step.

3.2 It is undisputed that the internal hub transmission shown in Figure 2 of E13 constitutes the closest prior art to the subject-matter of claim 1 of the 2**(nd) auxiliary request and that the claimed subject-matter is distinguished from this known hub transmission by the features defined in the characterising portion of the claim.

3.3 The technical effects achieved by these features are noise reduction (by the use of helical teeth in the respective components of the power transmission mechanism) and friction reduction (by the use of the first ball bearing assembly between the gear ring and the gear rack).

3.4 The next issue to be considered in the problem-solution approach is whether the two distinguishing features, though providing for two separate technical effects, do nevertheless contribute to solve a single technical problem. Since a well-known side effect of helical gears is that part of the torque transmitted between the gears is converted to an axial force, which needs to be supported by appropriately arranged axial bearings, a first ball bearing arranged between gear ring and gear rack could thus be seen as a technical consequence arising from the use of helical gears. It might thus be argued that both features contribute to solving a single technical problem of noise reduction.

However, the Board notes that the orientation of the helical teeth of the respective gears is not defined in the claim. Axial forces arising from their use could thus be directed in either direction along the axis of the relative rotating gears components, depending on the orientation of the helical teeth. The resulting forces on the gear rack and gear ring could therefore also act in opposite directions, tending to push those two components further apart. Consequently the first ball bearing assembly defined in claim 1 does not necessarily have to support such axial forces between respective axially abutting portions of the gear rack and the gear ring. Therefore the two distinguishing features do not necessarily contribute to solve a single technical problem; rather they relate to partial technical problems.

The Board thus concludes that the partial objective technical problems to be solved in regard to the closest prior art internal hub transmission of E13 can be seen as a) reducing noise and b) reducing potentially occurring frictional forces between the gear ring and gear rack.

3.5 The distinguishing features defined in claim 1 which provide the solutions to the respective partial problems belong to the common general knowledge of the skilled person. This as such was also not disputed by the proprietor. The proprietor disputed however that the skilled person would indeed have applied the respective features in the bicycle hub transmission of the closest prior art for several reasons. The Board is nevertheless not convinced by the proprietor's arguments and considers that the skilled person would have employed these well known features for their well known purposes in an internal hub transmission known from E13 and would thus have arrived without involving an inventive step at the combination of features according to claim 1. The reasons are the following.

3.5.1 As noted previously, compared to spur gears the reduction of noise by the use of helical gears belongs to common general knowledge, as well as the generally perceived disadvantages (inter alia, higher cost due to more complex manufacturing and a reduction of efficiency depending on the angle of the helical teeth with respect to the rotation axis). This is documented for example in E6, G124, right column under section 8, "Geräuschverhalten", G126, left column, "Schrägverzahnung". Being a general textbook on mechanical engineering, the teaching of E6 belongs also to the general knowledge of the skilled person designing internal hub transmissions of bicycles. Planetary gear transmissions are mentioned there in the left column on page G124 as one field of application for the different gear pairings, including helical gears. Balancing the well known advantages against the equally well known disadvantages of a particular technical feature is obvious for the skilled person.

Contrary to the proprietor's view, the Board cannot accept that the problems referred to in paragraphs 5 and 6 of E13 would have prevented the skilled person from considering helical gears. The cited paragraphs discuss drawbacks of prior art internal hub transmissions related to increased frictional forces which occur between a clutch member and parts of the planetary gear mechanism under high driving forces during a shift operation and which therefore require a higher force to be applied by the user on the shift lever for shifting of a corresponding control cable. These specific problems are solved in E13 by a particular clutch control mechanism (see paragraph 6). Although the use of helical gears is indeed generally known to be accompanied by an increase of frictional forces between the gears, compared to spur gears, the Board cannot see that the resulting frictional forces due to helical gears would necessarily amount to an instruction that would undermine the effects sought in E13. At least the proprietor did not provide any evidence for its assertion in this regard.

The mention in paragraph 63 of E13 of a planet roller mechanism instead of a planet gear mechanism also does not alter the Board's conclusion. The reference in paragraph 63 is far too general. An intended purpose for such alternative mechanism, let alone to the specific purpose of reducing noise, is in no way indicated. The knowledge of the skilled person that such roller mechanisms are quieter than gear mechanisms, as may arise for example from E14 and E16, cannot change the obviousness of the use of helical gears for their well known advantages.

Also the content of E16 does not support the proprietor's case. Rather than representing the general knowledge of the skilled person, the content of E16 represents merely an isolated opinion of a certain manufacturer of planetary gear transmissions. The Board cannot find any substantiated indication in E16 according to which the advantages attributed as a result of common general knowledge to the use of helical gears would be generally wrong. Despite mentioning at the end of the paragraph preceding the heading "Contra Schrägverzahnung" that noise reduction is less a question of using helical or spur gears than of machining precision when forming the teeth, this passage again simply confirms that helical gears are generally known for the previously mentioned advantages.

The Board concludes that the use of helical teeth for the different meshing components of the planetary gear mechanism is thus obvious for the skilled person.

3.5.2 The same conclusion is reached for the use of a ball bearing assembly between the gear rack 41 and the gear ring 43 of the hub transmission of E13, since ball bearings are well known for the purpose of reducing frictional forces between components which contact each other during their relative movement.

An indication that a gap existed between the respective facing portions of the gear rack 41 and the gear ring 43 which would exclude any contact between these components and therefore render a ball bearing at best useless and more importantly increasing friction, as argued by the proprietor, cannot be found in E13. Quite the contrary, the drawings suggest that during their relative rotational movement the relevant components indeed may come, or are continuously, in contact at their axially abutting faces and at their radially opposing respective inner and outer faces. For example, and as pointed out by the opponent, the different hatchings in the relevant portions in Figures 2, 3 and 7 to 8, terminate on a common line drawn to illustrate the limits of each of the two components 41 and 43, excluding the presence of a gap. Moreover, the entire structure of the hub transmission shown in these drawings suggests that the axially abutting faces of the gear ring 43 and the gear rack 41 block potential axial displacement which could otherwise occur during normal operation. The Board could at least not find any evidence of other axial stops in the drawings or in the description. The proprietor also did not indicate any support in E13 for other features preventing the normally occurring relative axial displacements towards each other of the components 41 and 43. In the absence of any clear disclosure of a gap, the skilled person would consider the mentioned opposing surfaces to constitute a source of friction which would be reduced by an appropriate ball bearing assembly.

Furthermore, the Board considers that the respective portions of the gear rack 41 and gear ring 43 offer sufficient material volume to accommodate bearing assemblies without requiring a major overhaul and without impeding the function of the relevant components. Since the claim is not limited by a particular angle of the helical teeth with respect to the rotation, even very small helix angles (e.g. 5 degrees) are covered by the claim. Axial forces resulting from such small helix angles will be relatively small (the resulting axial force depends on the tangent of the helix angle which becomes very small for such small angles). Small induced forces may therefore be supported by comparatively small bearing assemblies. The provision of such small ball bearing assemblies does not require a substantial overhaul of the internal hub transmission, contrary to the proprietor's argument.

Finally the Board cannot accept that assembling the internal hub transmission with such additional ball bearing assembly would confront the skilled person with particular difficulties. The gear rack 41 and the gear ring 43 of the hub transmission of E13 are two essentially tubular elements (cf. col. 5, lines 38/39, 46/48) fitted in a telescope-like manner with respect to each other (e.g. Fig. 2). Mounting a ball bearing assembly, which does not have to be large in size (see above) between the interior opposing faces of the two components does not go beyond the customary practice of the skilled person.

3.6 The Board therefore concludes that the subject-matter of claim 1 of the 2**(nd) auxiliary request does not involve an inventive step, contrary to Article 56 EPC. It follows that the patent cannot be maintained on the basis of the 2**(nd) auxiliary request.

7**(th) auxiliary request

4. Article 13(1) RPBA

4.1 The 7**(th) auxiliary request was filed during the oral proceedings before the Board, hence after the time limit for filing the appeal grounds or a reply to other party's appeal and therefore constitutes an amendment to the proprietor's case (Article 13(1) RPBA).

Any amendment to a party's case may be admitted and considered at the Board's discretion. The discretion shall be exercised in view of inter alia the complexity of the new subject-matter submitted, the current state of the proceedings and the need for procedural economy.

In order to be in line with the requirement of procedural economy, amendments should be prima facie allowable in the sense that they at least overcome the objections raised against previous requests without giving rise to any new ones.

4.2 In reply to the objections against the amendments to claim 2 of the 1**(st) auxiliary request (see point 2), claim 1 of the present request has been amended by defining all four ball bearing assemblies and by indicating a plurality of planetary gears through the use of the plural form "gears".

However, and as has been argued by the opponent, the resulting subject-matter would still contravene Article 123(2) EPC. Paragraph 37 in combination with Figures 2, 3 and 6 to 10 (see paragraph 32) together disclose a particular arrangement of (merely as one example) the first ball bearing assembly 160 supported between radially opposing portions, 142 and 128, of the gear ring 118 and the gear rack 116. Amended claim 1 in contrast leaves it open in which way the first ball bearing assembly is arranged in relation to these components. It encompasses for example also embodiments in which the ball bearing assembly could be arranged only between axially facing portions of the two components, for which there appears to be no basis in the application as filed.

The Board cannot accept the proprietor's argument that the terms "inner" and "outer" used in the description are of no significance in regard to a radial arrangement of the relevant features. For example, Figure 2 and paragraph 37 consistently disclose the outer bearing support portion 128 of the gear rack 116 as providing a radial inner support of the first ball bearing assembly 160, whereas the corresponding bearing support portion 142 of the gear ring 118 provides a radial outer support. The Board cannot find any inconsistencies in the reference signs of the relevant components. Finally, and as indicated before, paragraph 32 makes explicit reference to inter alia Figure 2 for the detailed description of the power transmission mechanism in the following paragraphs 33 to 43. The Board has therefore no doubts that the figures have to be considered for assessing whether the subject-matter of amended claim 1 extends (or not) beyond the content of the application as filed.

4.3 The Board concludes that amended claim 1 would not fulfill the requirement of Article 123(2) EPC. The 7**(th) auxiliary request is thus not prima facie allowable in the above sense. The Board therefore exercised its discretion under Article 13(1) RPBA not to admit the 7**(th) auxiliary request into the proceedings.

9**(th) auxiliary request

5. Article 13(1) RPBA

Also the 9**(th) auxiliary request was submitted during the oral proceedings. Taking into account the criteria referred to above under point 4.1, the Board exercised its discretion under Article 13(1) RPBA not to admit the 9**(th) auxiliary request into the proceedings for the following reasons.

The subject-matter of amended claim 1 is based on a combination of granted claims 1 and 5. Granted claim 1 corresponds to the combination of originally filed claims 1 and 2 while granted claim 5 corresponds to original claim 6 which was dependent only on claim 1. For similar reasons as already set out in regard to the main request (see point 1.3 above) the subject-matter resulting from the combination of granted claims 1 and 5, i.e. a combination of an internal hub transmission according to originally filed claim 1 with only a first ball bearing assembly and with the specific helix angle, cannot be derived directly and unambiguously from the application as filed.

The proprietor did not indicate any support for the amendments other than the claims, which is however, as explained, insufficient.

Amended claim 1 of the 9**(th) auxiliary request therefore at least prima facie does not fulfil the requirement of Article 123(2) EPC.

6. Absent any request which meets the requirements of the EPC, the patent has to be revoked according to Article 101(3)(b) EPC.