T 0289/95 04-03-1997

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

2. The content of the earlier (parent) application as originally filed

Claim 1 of the parent application is directed to a gasket for sealing for example the gap between a pipe spigot end and a pipe socket. The gasket is essentially of Z-shaped cross-section, with two main ("attachment" and "sliding" or "sealing") parts joined by a diagonally extending connection piece.

Figures 1 to 4 show a gasket of the claimed configuration, how it is mounted on a pipe spigot end and how the gasket behaves when the pipe spigot end is inserted into pipe sockets of various diameters. Figure 5 illustrates the manufacture of a pipe socket with a gasket of the claimed configuration mounted therein and Figures 6a and 6b show the insertion of a pipe spigot end into such a pipe socket.

In the second full paragraph of page 5 reference is made to the possibility of providing a closed sliding jacket on the gasket to facilitate assembly of the pipe spigot end and the pipe socket. It is indicated that this type of jacket is known from US-A-4 299 399 and in Figures 7a and 7b such a jacket is shown in combination with a gasket of the lamellae type. There then follows an explanation as to how the effective thickness of the gasket can be increased on assembly by having a jacket of increasing thickness towards its forward connection point to the gasket body. It is then stated in the last paragraph of page 5 that a larger increase of thickness can be achieved by a "newly developed embodiment" of the closed sliding jacket, described with reference to Figures 8 to 10.

In Figure 8 the closed sliding jacket is shown in combination with a Z-shaped gasket as illustrated in Figures 6a and 6b. Both ends of the closed sliding jacket are attached, slightly spaced from each other, to the leading or front edge of the sliding part of the gasket. The jacket increases in thickness from one end to the other, the thicker end being radially outermost. The other end is provided with an inward bulge adjacent its point of connection to the sliding part of the gasket. The inner surfaces of the jacket are provided with a suitable lubricant. The insertion of a pipe spigot end into the pipe socket is explained in paragraph 2 of page 6. The pipe spigot end first contacts the bulge of the jacket and then draws the jacket, with its inner surfaces sliding over each other and one of its outer surfaces rolling across the sliding part of the gasket, in such a way that it forms a double layer between the sliding part and the pipe spigot end. Figures 9 and 10 illustrate the effect of the length of the sliding jacket and the length of the axial movement between the pipe spigot end and the pipe socket on whether the jacket extends axially beyond the sliding part of the gasket after assembly.

Finally, in the penultimate paragraph of page 6 it is stated that

"from the description it will appear that this embodiment of a closed double sliding jacket is especially favourable in the described example, but the invention is not limited thereby, but can be used in connection with any other appropriate gasket structure"

and in the sentence bridging pages 6 and 7 that "for example, there can also be used a closed double sliding jacket in connection with that type of lamellae gasket illustrated in Figure 7, the sliding jacket being attached only to one point of the gasket body, for example in the area 17." (The reference numeral "17" is incorrect since it indicates a reinforcement on the outside of the gasket. Presumably the reference numeral "21" is meant.)

3. The subject-matter of the present patent

Figures 1a, 1b and 2 to 4 of the patent correspond to Figures 7a, 7b and 8 to 10 of the parent application, with Figures 1a and 1b being stated to show a prior art arrangement and Figures 2 to 4 embodiments of the invention.

The two-part form of claim 1 (quoted in Section I above) is however not derived from the state of the art shown in Figures 1a and 1b but from WO-A-81/03214, a document found in the search on the divisional application. It is to be noted that the preamble of the claim sets out the basic form of the gasket in very general terms.

4. The contested decision

Although the Opposition Division revoked the patent under Article 100(c) EPC the reasoning it used to come to the conclusion that the patent contained subject-matter extending beyond the content of the parent application was essentially different to the objections raised by the respondents in this respect.

In the opinion of the Opposition Division it was possible to identify in the parent application three combinations of features related to a gasket with a sealing body and a hollow jacket. These were the embodiment disclosed in the original claim 6 (a claim dependent on claim 1), the embodiment shown in Figures 8 to 10 and the embodiment shown in Figures 7a and 7b. The kernel of the Opposition Division's thinking is then summed up in the statement that

"as the original description does not mention or suggest any other embodiments, the main claim must be related to one of these embodiments with all and only their respective features". Since this was found not to be the case it was held that the subject-matter of claim 1 went beyond the content of the parent application as originally filed. It is not clear to the Board why the Opposition Division made no reference in its decision to independent claim 7 of the parent application and refused to consider the penultimate paragraph of page 6, quoted above, and the sentence bridging pages 6 and 7 as constituting a general disclosure that a closed sliding jacket of the type shown in Figures 8 to 10 could be used not only with gaskets having a Z-shaped configuration, but with gaskets of any other appropriate structure. In view of that independent claim and the relevant passages of the description, the Board is convinced that the person skilled in the art would understand the parent application as teaching the use of a closed sliding jacket of the basic form shown in Figures 8 to 10 with any form of gasket of the general type set out in the first part of the preamble of claim 1 of the contested patent. The objection of the Opposition Division in this respect does not therefore hold good.

The Opposition Division also agreed with the objection of the respondents to claim 2 of the contested patent. This objection is dealt with below.

5. The objections of the respondents under Article 100(c) EPC

The objections of the respondents under this head cover the whole spectrum from straightforward addition of features which have no counterpart at all in the parent application via what are often termed "intermediate generalisations" to the concept of "addition by omission". Since the last issue is the one on which the respondents, at least in the oral proceedings before the Board, seemed to place the most weight, it is convenient to deal with it first.

According to the respondents, independent claim 7 of the parent application required that both ends of the closed sliding jacket were directly connected to the front edge of the sealing part of the gasket. Figures 8 to 10 clearly showed such an arrangement, the ends of the jacket being spaced apart by the said front edge, and nothing else was suggested as being possible. Claim 1 of the contested patent on the other hand now covered two arrangements which had not been originally disclosed. In the first of these the ends of the jacket are connected to each other and then via a connection piece of some description to the gasket. That this arrangement was envisaged by the claim was made clear by the reference to the wall of the jacket "forming a closed cavity", i.e. by itself and without the help of part of the gasket. In the second of the arrangements now claimed but not originally disclosed only one end of the jacket is connected to the front end of the gasket and the other is connected to the gasket at a position axially spaced therefrom.

Here, it is necessary to clarify that the question of whether or not a claim in a patent deriving from a divisional application "covers" or "embraces" something which was not specifically disclosed in the parent application is not the proper standard of comparison for determining whether there has been an inadmissible extension of subject-matter. What is required (see T 514/88, OJ EPO 1992, 570 and T 527/88 of 11 December 1990, not published in OJ EPO) is an analysis of whether the subject-matter of the contested patent is directly and unambiguously derivable from, and consistent with, the disclosure in the parent application.

In the opinion of the Board there is nothing in the wording of independent claim 7 of the parent application which requires a direct connection of both ends of the jacket to the front edge of the sealing part of the gasket. Furthermore, there is nothing in the description of Figures 8 to 10 or inherent to the way the jacket is intended to function which could indicate that such a direct connection is necessary. Thus the person skilled in the art would understand that independent claim 7 was intended to embrace not only arrangements where the ends of the jacket are separately connected to the front edge of the sealing part of the gasket, as shown in Figures 8 to 10, but also embodiments where the sliding jacket itself forms a closed cavity and is attached to a single point on the gasket body as suggested in the sentence bridging pages 6 and 7, and accordingly an arrangement, now criticised by the respondents as being added subject-matter, in which the ends of the jacket are joined together before they are connected to the front edge of the sealing part.

As for the second arrangement (see above) identified by the respondents as being covered by present claim 1 but not originally disclosed it is the opinion of the Board that this arrangement is in fact excluded by the wording of the claim which requires that the jacket be connected with the forward end of the sealing body and "wholly positioned in front of the sealing body in the starting position of the assembly". It cannot be seen how that requirement could be met in the arrangement envisaged by the respondents in which one end of the jacket was attached to the sealing body at a position axially spaced rearwardly of its forward end.

Accordingly, this first objection of the respondents fails.

The second objection to claim 1 particularly relied upon by the respondents at the oral proceedings was the absence from the claim of the feature that the jacket has increasing thickness from one end to the other. The respondents saw this as being an essential feature for the solution of the problem with which the closed sliding jacket as originally described and claimed was involved. That conclusion appears however to be based on a mis-reading of the parent application from which it is clear that the primary advance of the described closed sliding jacket over the known type of jacket shown in Figures 7a and 7b is that it forms a double rather than a single thickness layer between the gasket proper and the part to be sealed against. Particularly since the use of a jacket wall having increasing thickness has already been discussed in the penultimate paragraph of page 5 with relation to the known type of jacket, it is evident that this is a subsidiary and not an essential feature of the closed sliding jacket shown in Figures 8 to 10.

The second objection of the respondent therefore also fails.

The other objections to claim 1 are more straight-forward. The respondents can find no support in the parent application for the statements that the jacket is "flattened with two opposite inner surfaces of the wall contacting each other essentially along their entire length during assembly and in the assembled position", that the rolls on assembly in "a manner similar to a caterpillar belt" and the jacket is "at least partially" positioned between the sealing body and the opposite sealing surface after assembly. With regard to the first two of these statements it is true that no exactly equivalent form of words can be found in the parent application, but that is not the point. It is the technical content of the statements that counts, not the words themselves. It is unequivocally clear from the description of Figures 8 to 10 of the parent application that the jacket behaves in the way required by these statements. Although the term "caterpillar" is in fact a trade name and thus should not be used in a claim, it has a well-established technical meaning, cf the Shorter Oxford English Dictionary: "Trade name for either of two endless metal belts or treads, one on each side of a vehicle, which facilitate travelling over very rough ground". As for the third term objected to this has a clear basis in Figures 9 and 10 of the parent application which respectively show the jacket partially and fully positioned between the sealing body of the gasket and the pipe spigot end.

Thus none of these objections can succeed.

Finally, the objection of the respondents against claim 2 of the contested patent needs to be considered. The respondents argue that the parent application disclosed the provision of a bulge in the jacket adjacent its connection point to the forward edge of the sealing part of the gasket as the only possibility of adapting the shape of the jacket so that it "will be carried along by a sealing surface during assembly" as required by claim 2. That claim however made no mention of a bulge or its position and therefore "covered" many other arrangements not originally disclosed. This is true. But it is not the point. What matters is what the claim discloses, not what it covers. The claim is in fact drafted in such broad terms that it says nothing which is not already inherent to the gasket defined in claim 1. This makes the claim effectively redundant, as the appellants have admitted, but any possible objection to this under Article 84 EPC is not a ground of opposition. In view of the above the objection raised against claim 2 under Article 100(c) EPC does not hold good.

6. Remittal

The grounds of opposition under Articles 100(a) and (b) EPC have not yet been considered by the Opposition Division. In circumstances such as these it is the general practice of the Boards of Appeal to remit the case to the Opposition Division for further examination and that is the appropriate course of action to take in the present case. Thus, although the contested decision is to be set aside, the Board is not in a position to grant the request of the appellants that the patent be maintained unamended.