T 0232/00 22-03-2001

Reasons for the Decision

1. The appeal is admissible.

2. Amendments

2.1. Claim 1 as granted defined a sealing arrangement and so the amendment to define a use concerns a change of category after the patent has been granted. The question whether such a change is in compliance with the provisions of Article 123(3) EPC in such a case was answered positively in decision G2/88 (Point 5 of the reasons) and, since the respondent has not challenged this point, need not be considered further. However, the respondent does challenge in accordance with the provisions of Article 123(2) EPC the disclosure of the application as originally filed in respect of both the use of the sealing arrangement with perfluoropolyethers and the possibility of claiming protection for its use.

2.2. The application as originally filed begins by discussing prior art arrangements for sealing against a rotating shaft in general and in column 1, lines 34 to 44. explains that particular problems existed in respect of perfluoropolyether lubricants which exhibit low surface tension and so are difficult to contain with a conventional shaft seal. In the subsequent text (column 1, lines 45 to 48) it is stated that the invention is concerned with a sealing arrangement which in general overcomes, or at least mitigates or minimizes, such difficulties. Those difficulties will be overcome only if the sealing arrangement is actually used with perfluoropolyethers and the use of the sealing arrangement in conjunction with perfluoropolyethers is therefore implicitly disclosed. Moreover, the claimed effect of the use of the sealing arrangement "such that any of the liquid lubricant escaping ... enters in to and is constrained in the cavity to form a well of the liquid lubricant at the base thereof until sufficient liquid lubricant is present in the cavity to impinge on the conical portion of the shaft and thereby be urged by centrifugal force towards the sealing lip" is implicit from the disclosure of the application as originally filed in column 2, lines 14 to 20 relating to the sealing arrangement having the radially extending apertured plate member which now forms part of the subject-matter of Claim 1.

2.3. The respondent's objection under Article 123(2) EPC in respect of the change of category of Claim 1 relates to the question of disclosure in the application as originally filed of the protection which is to be sought. As set out by the Enlarged Board of Appeal in Decision G 2/88 in Point 5 of the reasons, 3rd paragraph, it is generally accepted as a principle underlying the EPC that a patent which claims a physical entity per se confers absolute protection upon that physical entity, including for all uses thereof. It follows that a claim in an application as originally filed to a product is a disclosure of seeking protection which would cover also the use of that product. The claims as originally filed in the present case relate to a sealing arrangement and the amendment of the category of the claims to the use of the sealing arrangement serves merely to exclude some of the protection which effectively would have been afforded by the product claims. Since this use was implicitly addressed in the original application (see paragraph 2.2) the amendment of the category of Claim 1 does not lead to the subject-matter of the application extending beyond the content of the application as originally filed.

2.4. The description and the dependent claims have been amended essentially only for consistency with Claim 1.

2.5. The Board therefore finds that the requirements of Article 123(2) EPC are fulfilled.

3. Novelty

None of the cited prior art documents relates to the use of a sealing arrangement in conjunction with perfluoropolyethers and following amendment of Claim 1 to define such a use the Board is satisfied that the subject-matter of the claim is novel. Indeed, the respondent no longer objected in accordance with Article 54 EPC.

4. Inventive step

4.1. The problem to which the subject-matter of the patent relates is that of providing a seal to a rotatable shaft to satisfactorily constrain perfluoropolyether lubricants, which exhibit a low surface tension (column 1, lines 36 to 50). The wording of Claim 1 requires that the sealing arrangement is used "such that ... lubricant ... is constrained ... to form a well ... until sufficient liquid lubricant is present ... to impinge on the conical portion of the shaft and thereby be urged by centrifugal force towards the sealing lip ... ". Since this effect of centrifugal force requires that the shaft rotates, it follows that the subject-matter of the claims necessarily involves the rotation of the shaft in providing the improved sealing properties.

4.2. D1 concerns a sealing arrangement for a vehicle wheel bearing (page 1, 1st paragraph). In the detailed embodiment the sealing arrangement is between the wheel hub 1 and the axle 2 on which the wheel is mounted by means of a taper-roller bearing 3, 4, 5, the inner race 5. of which is shown in the sole figure as being mounted on and, implicitly, stationary relative to the axle 2. The inner race 5 is shown but not described in the text, as having a conical portion which, together with the sealing lip 12 engaging the inner race 5 and a dust protection lip 10 in the form of a radially extending apertured plate member engaging the axle 2, defines a cavity 14. In the opinion of the Board it is implicit for the skilled person that in the disclosed embodiment the wheel rotates around the stationary axle. Moreover, taper-roller bearings in vehicle wheel assemblies are lubricated by grease which according to D1 fills the cavity 14 (description, final sentence). It follows that there is no disclosure regarding a function of the conical portion to urge liquid towards the sealing lip 12. by means of centrifugal force. The Board is of the opinion that the skilled person wishing to achieve satisfactory sealing to a rotating shaft to constrain perfluoropolyethers would not choose as the starting point a sealing arrangement such as is disclosed in D1 in which the shaft is stationary and the seal is effective against a lubricant having quite different physical properties. D1 therefore does not form the closest prior art for Claim 1.

4.3. D2 concerns an improvement in oil lubricated bearings in traction motors subjected to movement or vibration which causes splashing of the oil (page 1, left hand column, lines 1 to 22). The prior art arrangement from which D2 starts employed a felt member 18 partially immersed in a reservoir of oil and which served to provide oil to a rotating shaft member 11 carried in the bearing (page 1, right hand column, lines 11 to 35). Oil was present on both sides of the felt member by virtue of its passage through peripheral openings 16a, 17a in washers 16, 17 which housed the felt member. Since the oil was on both sides of the felt member, D2 starts from an arrangement which does not have a shaft seal with a sealing lip defining an air side and a liquid side. The improvement which D2 aims to achieve is to prevent the oil from splashing from the reservoir level 20 up to the level of the shaft and for this purpose a seal member 25 is introduced adjacent one of the washers 17. A conical portion located within a cavity defined between the seal member 25, the washer 17 and a radially extending apertured member 22 is shown on the rotating shaft member 11 but is not mentioned in the text. However, even with this additional seal member 25, there is no disclosure for the skilled person that a sealing arrangement defining an air side and a liquid side is achieved. Therefore also D2 does not form the closest prior art for Claim 1.

4.4. D3, which was not used by the respondent during the appeal procedure, relates to a seal between the inner and outer races of a ball bearing and also in the opinion of the Board is not of relevance to the present case.

4.5. In the opinion of the Board the closest prior art is that which the appellant acknowledges in the description of the patent specification (column 2, lines 9 to 12) as corresponding to the preamble of Claim 1 as granted, whereby the novel constructional features are those relating to the annular cavity. In the use defined in Claim 1 in suit, perfluoropolyethers which escape past the sealing lip may be thrown from the shaft and build up in the annular cavity until sufficient liquid is present to contact the conical surface and thereby be propelled back towards the seal. In the absence of the annular cavity, liquid passing the lip seal would be thrown from the shaft and would be lost. The novel features of Claim 1 therefore solve the problem of reducing the loss of perfluoropolyether lubricant which leaks past the seal of a rotating shaft.

4.6. Neither D1 nor D2 relates to the problem solved by the novel constructional features. Since the shaft 2 of D1 does not rotate, any liquid which might pass the lip seal 12 would not be thrown to the base of the cavity 14. but would simply remain on the surface of the inner race 5 and centrifugal force could not serve to return the liquid to the area of the lip seal. As regards a kinematic inversion of the sealing arrangement of D1 resulting in rotation of the shaft 2, as suggested by the respondent, there is no reason for the skilled person to expect that the arrangement would be suitable for use with perfluoropolyethers since they exhibit such different physical properties to the grease with which D1 is intended to be used and the skilled person therefore would receive no encouragement in this direction. The seal member 25 which is added to the arrangement according to D2 and which forms an annular cavity is specifically provided for controlling movement of fluid from the oil reservoir towards the shaft, in a direction opposite to that of any liquid which might pass between the seal 18 and the shaft. The idea of an implicit teaching in D2 of a well of oil collecting in the cavity, which potentially could be splashed against the shaft, is contrary to the teaching of D2 in adding the seal member 25 in order to avoid oil from being splashed against the shaft. It follows that neither D1 nor D2 gives the skilled person any encouragement to add to the closest prior art sealing arrangement features relating to the annular cavity in order to solve the problem set.

4.7. The Board therefore finds that the subject-matter of Claim 1 does not derive in an obvious way from the prior art and concludes that the subject-matter of Claim 1, and therefore also of Claims 2 to 8, involves an inventive step (Article 56 EPC).