T 1135/97 () of 2.7.1999

European Case Law Identifier: ECLI:EP:BA:1999:T113597.19990702
Date of decision: 02 July 1999
Case number: T 1135/97
Application number: 91308030.5
IPC class: F02F 11/00
Language of proceedings: EN
Distribution: C
Download and more information:
Decision text in EN (PDF, 38.634K)
Documentation of the appeal procedure can be found in the Register
Bibliographic information is available in: EN
Versions: Unpublished
Title of application: Metallic Gasket
Applicant name: Nippon Gasket Company Ltd.
Opponent name: Elring Klinger GmbH
Reinz-Dichtungs-GmbH
Board: 3.2.04
Headnote: -
Relevant legal provisions:
European Patent Convention 1973 Art 56
Keywords: Inventive step - yes
Technical teaching derivable from feature solely in a drawing
Catchwords:

-

Cited decisions:
T 0002/83
T 0204/83
Citing decisions:
T 0492/04

Summary of Facts and Submissions

I. European patent No. 0 494 489 was revoked by the opposition division's decision dispatched on 4 November 1997.

The proprietor filed an appeal and paid the fee on 20. November 1997 and filed a statement of grounds on 10. March 1998.

II. Claim 1 of the main request as submitted in the oral proceedings before the opposition division reads:

"A metallic gasket (1) comprising a bead-carrying base member (10) which is formed out of an elastic metallic material and has a flat surface (14), first cylinder bore-aligned holes (2) formed in parallel with one another in said bead-carrying base member (1), an auxiliary member (11) laminated on said bead-carrying base member (10) and formed out of a metallic material, and second cylinder bore-aligned holes (3) formed in said auxiliary member (11) so that said second holes (3) are in parallel with one another and in alignment with said first holes (2); and beads (12) formed so as to project from the portions of said flat surface (14) of said bead-carrying base member (10) which extend along the circumferential edges of said first cylinder bore-aligned holes (2); and folded portions (13) formed by folding the portions of said auxiliary member (11) which correspond to the circumferential edge portions of said second cylinder bore-aligned holes (3) toward said bead-carrying base member (10);

characterised by said auxiliary member (11) being laminated on the side of said bead-carrying base member (10) from which said beads (12) project, with free end portions of said folded portions (13) not superposed on said beads (12), said folded portions (13) of said auxiliary member (11) being spaced in a no-load state from said flat surface (14) of said bead-carrying base member (10), and said folded portions (13) and said beads (12) being provided in a spaced manner so that said folded portions (13) and said beads (12) are not superposed on each other, and adjacent beads (12) meet each other in regions between adjacent holes (2) to be united into a single bead portion (12) respectively."

III. The following documents were referred to in the appeal proceedings:

D5: JP-U-62-115 562

D5': JP-Y-4-16 026

- D5 and D5' are present in various copies with various translations

D9: "Die Zylinderkopfdichtung in der Patentliteratur Teil III", MTZ Motortechnische Zeitschrift 48 (1987) 12 (pages I to VIII)

D11: US-A-4 861 047

D12: DE-C-3 724 862

D13: DE-C-2 849 018

D14: JP-U-63-180 769 (a single page) and a translation into English

IV. Oral proceedings with all parties present were held on 2. July 1999.

During the appeal proceedings the appellant (proprietor) argued that neither D5' nor D14 would teach the skilled person not to superpose the beads of the base member and the folded portions of the auxiliary member. Accordingly no combination of the available prior art would lead the skilled person to the claimed subject-matter.

During the appeal proceedings respondent I (opponent I) argued that the claimed subject-matter was not novel over D14. Both respondent I and respondent II (opponent II) argued that the claimed subject-matter was not inventive starting from D5' or D14. Respondent II maintained that claim 1 of the auxiliary request contravened Article 123(2) EPC.

V. The appellant requested that the decision under appeal be set aside and the case remitted to the first instance with the order to maintain the patent on the basis of either the main request or the auxiliary request:

- the respective claim 1 of which as submitted in the oral proceedings before the opposition division,

- claims 2 to 8 as granted,

- columns 1 to 2 and 5 to 13 of the description as granted,

- columns 3 and 4 of the description as submitted in the oral proceedings before the board of appeal, and

- the drawings as granted.

The respondents requested that the appeal be dismissed.

Reasons for the Decision

1. The appeal is admissible.

2. Amendments - the main request

2.1. Claim 1 of the main request consists of all the subject-matter of the granted claim 1 with the added features of "said folded portions (13) and said beads (12) being provided in a spaced manner so that said folded portions (13) and said beads (12) are not superposed on each other, and adjacent beads (12) meet each other in regions between adjacent holes (2) to be united into a single bead portion (12) respectively."

The board sees a basis for these added features in the application as originally filed and in the granted patent, and this has not been disputed by the parties. Moreover these added features plainly restrict the scope compared with that upon grant, and also more clearly define the technical area where the gasket is used, namely cylinder blocks with small distances between adjacent cylinder bores.

2.2. The dependent claims are unchanged and the description of the main request differs from the granted description merely by being brought into line with claim 1 of the main request. There is no change to the drawings.

2.3. Accordingly the board concludes that the patent version according to the main request does not contravene Article 123 EPC.

3. Interpretation - claim 1 of the main request

3.1. The word "laminated" appears in this claim in the features "an auxiliary member (11) laminated on said bead-carrying base member (10)" and "said auxiliary member (11) being laminated on the side of said bead-carrying base member (10) from which said beads (12) project".

"Laminated" means that the auxiliary member and the base member contact each other i.e. directly. As stated in lines 11 to 16 of column 10 of the granted description (lines 13 to 17 of page 21 of the originally filed description) and as confirmed by the appellant during the oral proceedings, this contact occurs both in the no-load state (before tightening between the cylinder head and the cylinder block) and the loaded state.

3.2. A "member" is an individual component which is individually formed, the term "member" cannot be construed as consisting of two or more separate components - for this the word "assembly" would be used. In the oral proceedings the appellant confirmed this interpretation.

3.3. "Laminated" entails (direct) contact and excludes an intermediate member. If the members are coated, see lines 23 to 31 of column 9 of the granted description, then these thin coatings are part of the members, they cannot be seen as additional members. This means that the members are still in contact with each other.

3.4. Since the claim speaks of the metallic gasket comprising a bead-carrying base member and an auxiliary member, it cannot be excluded that there are other layers as well. Nevertheless - see sections 3.1 and 3.3 above - the base member and the auxiliary member must contact each other (directly), i.e. the claim cannot be construed as covering these members with an extra layer or layers simply added therebetween.

4. The non-superposition of the beads and folded portions

Lines 28 to 33 of column 5 of the granted description explain that the folded portions of the auxiliary member function as stoppers for the bead-carrying base member, restrict the deformation of the beads and minimize the occurrence of fatigue cracks in the beads. It has never been disputed that the functioning of the beads would be different if the folded portions came into contact with the beads upon installation of the gasket instead of being non-superposed as set out in claim 1 of the main request. Therefore it has to be stated that the feature of the folded portions and the beads not being superposed is technically relevant and clearly indicates what is meant, namely that in both the non-loaded and the loaded sate of the gasket there will always be a well defined structural relationship between the folded portions and the beads.

5. Novelty - claim 1 of the main request

5.1. Respondent I mentioned D14 for the first time in the letter of 27 August 1998 stating that it had become known from another proceedings and that it obviously used a common bead between neighbouring closely spaced cylinder bores, see e.g. Figures 1, 2(a) and 2(b), the latter being sections Y-Y' and X-X' on Figure 1.

5.2. In the oral proceedings respondent I argued for the first time that D14 was in fact a novelty-destroying document.

Objecting to the use of D14 in this way, the appellant pointed out that novelty had not until then been at stake in the appeal proceedings and indeed had not been at stake at the time of the opposition division's decision. While maintaining to be unprepared for detailed discussion of this document (that originated from the appellant), the appellant was able to add that the translation was of uncertain origin and authenticity, that the single cited page of D14 (not the translation) indicated the existence of a second page which had not been provided by respondent I, and that it could not be determined where on Figure 1 the sections 2(a), 2(b) and 3(a) to 3(d) were taken and what they showed. Moreover the appellant was able to refer to the document D14 during the later discussion on inventive step (see also the appellant's letter of 1. June 1999, page 2, sixth and seventh paragraphs).

5.3. The board however decided to take D14 into consideration in the framework of inventive step, while bearing in mind that, although it was not possible in the oral proceedings to determine the accuracy of the translation of D14, the filed translation, accurate or not, anyway does not fully explain the drawings.

For example parts 6 on Figures 2(a) and 2(b) are termed stoppers and Figure 3 is said to show "examples of the stoppers of larger volume" which implies, albeit unrealistically, that Figures 3(a) to 3(d) show solely stoppers.

5.4. Claim 1 of the main request includes the requirements of "folded portions (13) formed by folding the portions of said auxiliary member (11)" and "said auxiliary member (11) being laminated on the side of said bead-carrying base member (10) from which said beads (12) project".

Assuming that Figures 3(a) to 3(d) show respective sections through four different gaskets, then only Figure 3(d) seems to show a folded member on that side of another member from which the bead projects. However in Figure 3(d) the bead apparently directly faces not the folded member but an intermediate member. As shown in Figure 3(d) the bead-carrying member is not laminated to any other member (i.e. not in contact therewith, see section 3 above). Moreover even if Figure 3(d) were showing an exploded view and layers in actual fact were in contact then the bead would be in contact with the intermediate member not the folded member. Only in the loaded state could the bead-carrying member contact the folded member (this would be at their edges) but it has been stated in section 3.1 above that the claimed lamination must occur also in the no-load state.

5.5. Thus, D14 does not disclose all the subject-matter of claim 1 of the main request, at least because D14 does not show lamination of a bead-carrying member and a folded member.

5.6. As the concept of novelty under the EPC is narrow, respondent I when alleging that this claimed difference over D14 is trifling must do this under obviousness and not novelty (see section 8 below).

5.7. After examination of the prior art documents on file other than D14, the board is satisfied that none of them discloses a metallic gasket with all the features of claim 1 of the main request. This was not disputed by the parties in the oral proceedings.

5.8. The subject-matter of claim 1 of the main request is thus considered novel within the meaning of Article 54 EPC.

6. The disclosure of D5

6.1. D5 was published on 22 July 1987. A first copy of D5 with a translation was filed by respondent I with the letter of 6 March 1997 and a second, different copy was filed by respondent II with the letter of 21 March 1997. The appellant filed a third copy, a copy of the microfilm version, with the letter of 10 March 1998.

The Figure numbers of D5 referred to below apply equally to all three copies of D5.

6.2. D5' - being a later version of D5 - was published on 10. April 1992 i.e. after the present patent's priority and filing dates (9 January 1991 and 2 September 1991 respectively). Thus D5' is disregarded by the board.

Respondent I has filed no evidence in support of its argument that D5' should be taken into account because, although published too late, it showed that the original D5 was unclear and that the Japanese examiner realised what amendments had to be made to clarify it.

6.3. The point at issue regarding the disclosure of D5 is whether it teaches the skilled person not to superpose the folded portions 40 of the sub-plate 22 and the annular beads 36 of the base plate 20 (see Figures 1, 3 and 5, and page 7, lines 1 to 14 of the English translation).

It is undisputed that the description of D5 is silent on whether the folded portions and the beads should be superposed or not. Respondent I's arguments rely on the Figures of D5 being accurate enough for the skilled person to be able to draw conclusions therefrom.

6.4. The board must say at the outset that it does not accept this view but considers that patent drawings are generally schematic (particularly in the absence of an indication in the document to the contrary) and that in particular Figures 1, 3 and 5 of D5 were never meant to be used as precisely as needs to be done to support respondent I's arguments.

The board's view on this point is supported by the various decisions cited by the appellant, the key one of these being T 204/83 (OJ EPO 1985, 310 - see e.g. section 7), and indeed supported by respondent II (see the second sentence of section 2.2.5 of the letter of 30. July 1998).

6.5. Figure 1 of D5 shows intake (12) and exhaust (14) valves in what is obviously a schematic way, the unrealistic size of the piston rings relative to the piston show that also these are not drawn to size. The wall between the cylinder bore 4 and the water jacket 16. is obviously unrealistically wide compared to the diameter of the piston 8. This unrealistic depiction of the cylinder block 3 naturally means that the gasket 1 shown above the cylinder block with bores in line is also unrealistically depicted. This is confirmed by comparing the ratio of the bore-to-bore distance to the bore diameter on Figure 1 with that on Figure 2, although Figure 1 is apparently a section on line I-I of Figure 2.

As Figure 1 is undoubtedly very far from being drawn to scale, it is not realistic to expect anyone to draw a meaningful teaching from Figure 1 concerning the relative positions of the folded portions and the beads. Moreover there is no reason to suppose that Figures 3 and 5 are drawn any more accurately than Figure 1.

6.6. However in the next section the board will go along with the viewpoint of the Figures being accurate in order to see what the consequences would be.

6.7. Three folded portions are shown on Figure 1. It is difficult to distinguish the left-hand folded portion from the lines delimiting the height difference h but, as far as the board can see, the free end of the folded portion is roughly in line with the junction of the annular bead 36 and the base plate 20. This seems also to be the case for the middle and the right-hand folded portions on Figure 1. In Figure 3 the bead clearly overlaps the free end of the folded portion whereas in Figure 5 (showing a different embodiment) the bead clearly does not overlap the free end of the folded portion.

Figure 3 shows the same embodiment as Figure 1 but on a larger scale. It might be held therefore that the superposition condition of Figure 3 also applies to the rather unclear Figure 1, this however would not be what claim 1 of the main request demands.

It is only Figure 5 that shows a non-superposition of folded portion and bead. However Figure 5 is a section on line V-V of Figure 4 i.e. a transverse section. It cannot be automatically assumed that the situation in Figure 5 occurs all around the bore 24 and especially between two bores where two beads and two folded portions need to be present in a restricted space, particularly since the folded portion 40 cannot be seen on Figure 4.

6.8. Even if D5 might be considered as showing three conditions: superposition, non-superposition, and coincidence, then the board considers that these three conditions would not have been intentional but merely the result of the drafter of D5 not being concerned in the slightest with whether the free end and the bead were superposed or not. If he had been concerned, then he would have drawn them consistently and drawn attention to them in the description.

6.9. In the board's view, the skilled person would not engage in this complicated consideration of whether the folded portions and beads of D5 were superposed or not, unless he had been given reason so to do by knowledge of the present invention. Only then would he be interested in something which did not interest the drafter of D5.

6.10. Respondent II argued (see sections 2.2.1 to 2.2.5 of the letter of 30 July 1998) that the claimed non-superposition of the folded portions and the beads is a negative feature and so could not possibly be mentioned in D5. If a feature was not mentioned then the skilled person would have assumed that it was not present. Without knowledge of the present patent, the skilled person would have had no reason to expect that the folded portions and the beads overlapped in D5 and (see section 2.2.4) would not have seen a contradiction in Figure 3 of D5. The skilled person knew that drawings in such documents were only schematic and if corresponding parts were shown differently in different drawings then the skilled person would not have assumed that the differences were deliberate.

The board cannot accept this reasoning. Patent documents commonly omit features which are of no relevance to the invention being presented therein. A patent for an engine therefore does not list all the many components which are conventional e.g. the intake valves. Failure to mention the intake valves would not mean that there were no intake valves in the engine.

The failure to mention in D5 whether there is an overlap, and the apparent contradiction between Figures 3 and 5, shows that the skilled person had given no thought to the overlap aspect - it cannot be assumed that therefore there is no overlap.

6.11. Moreover D5 depicts the gasket in its unloaded state (see the undeformed beads 36 and the gap between the folded portions 40 and the base plate 20). Even if it could be assumed that the beads and the folded portions are not actually superposed in the unloaded state (e.g. if Figure 1 were held to depict the borderline condition of the ends of the beads being in line with the ends of the folded portions) then it does not follow that these would remain non-superposed in the loaded and operational states with the beads partially flattened and the whole gasket subject to cyclical thermal and pressure loading.

6.12. The board concludes that D5 does not disclose the feature that the folded portions and the beads are not superposed and that the document is of very limited value indeed and provides a rather unsuitable foundation for an obviousness attack.

7. Inventive step - claim 1 of the main request - starting from D5

7.1. The respondents argue that the skilled person starting from D5 would arrive in various obvious ways at the subject-matter of claim 1 of the main request, namely by using the teachings of D11, D12 or D14.

7.2. All these approaches rely on the argument that D5 teaches the skilled person not to superpose the folded portions of the sub-plate and the annular beads of the base plate. Since the latter argument is incorrect (see section 6 above), all the approaches relying thereon must also be incorrect.

Respondent II argues that there were only two possibilities in D5, namely either the parts are superposed or they are not, and that the skilled person needs only to make an obvious selection from these two possibilities. The board cannot agree. The skilled person would not be aware from D5 that there is a choice to be made because D5 does not draw his attention to this point. At best D5 teaches him that it does not matter whether they are superposed (Figure 3) or not (Figure 5).

Neither would the skilled person automatically assume that avoiding contacting the bead was the only sensible solution since e.g. D9, Figure 2 c) on page I and Figure 10 c) on page IV, and D13, Figures 2 and 3 show bead contact. The respondents while emphasising this argument did not rely on any specific evidence thereof.

7.3. Before turning to the remaining state of the art to investigate whether the skilled person would be guided towards the claimed subject-matter, the board wishes to focus on the starting point chosen for assessing inventive step, i.e. D5.

The patent in suit is directed to metallic gaskets to be used in engine blocks with small distances between the cylinders. Small distances between cylinders, with its advantages and disadvantages, is a concept known to the skilled person in the art. The engine block construction of course is reflected in the corresponding gaskets. It is also a known concept for the cylinders in engine blocks to be separated sufficiently widely to enable cooling between the cylinder bores, see D5.

If the skilled person, knowing both these concepts, intended to finish up with an engine block and gasket of the small spacing concept, then it does not seem reasonable that he would start off by ignoring a gasket of this small spacing concept, select instead a gasket of the other concept (widely spaced bores with cooling therebetween) but then go on to adapt this wide spacing concept gasket to make it suitable for the small spacing concept (the concept which he deliberately rejected at the start).

What would be obvious would be to select a gasket according to the intended i.e. end concept and then to develop it. Thus it would be obvious to select a gasket of the concept having widely spaced bores with cooling therebetween and develop it to finish up with a gasket of this same concept. Switching between these known concepts suggests an approach based on knowledge of the patent in suit (cf. "Case Law of the Boards of Appeal of the EPO", 3rd edition 1998, page 112, section 3.2 "Choice of the closest starting point").

Already for this reason, the board is unconvinced that, starting from D5, it would be possible in an obvious manner to arrive at the claimed subject-matter.

7.4. It is argued that D11 teaches combining adjacent beads into a single bead and would therefore lead the skilled person to combine the two beads shown to the right of the piston 8 in Figure 1 of D5 into a single bead.

Figures 1 and 2 of D11 show the combining of a bead A12 surrounding a push rod hole Hp in a plate A10 with an outer bead A11, a depression A14 being provided to improve the flexibility of the beads at the intersecting portion A13 (see column 2, line 67 to column 3 line 10).

It is noted therefore that these beads A11 and A12 intersect at right angles and all the other beads depicted in Figures 3, 5 and 6 actually intersect and do this at a sharp angle. Also, claim 1 of D11 speaks of the "beads intersecting with each other".

The board considers that D11, while teaching combining intersecting beads, does not teach combining the beads surrounding the cylinder holes Hc. If these holes were so close that the beads ran into each other then one would better describe them as touching each other tangentially than as intersecting, the term used in D11. Moreover, while the cylinder holes Hc are shown on Figure 1 of D11 to be extremely close, no mention is made in the description of combining the cylinder hole beads and indeed the dotted lines around the cylinder holes Hc in this Figure show that the beads are in fact separate.

7.5. Figure 4 of D12 shows a common intermediate piece 40 joining rings 39 with a cover 33, the whole assembly being held in a carrier plate 31 with linked openings 34. However the whole concept of this gasket with its linked openings and inserts differs so greatly from that of D5 that the board cannot see that the skilled person would be led to combine their teachings.

7.6. The skilled person is also taught by D14 that a common bead can be provided between adjacent combustion chamber holes (see Figure 1 and the middle of the translated claim - assuming the translation to be accurate in this respect).

The board however cannot accept the argument that the skilled person would start from the gasket of D5, apply the teaching of D14 to provide a common bead between the latter's bores 24, and so arrive at a gasket satisfying claim 1 of the main request.

Firstly, the claimed feature of not superposing the folded portions of the sub-plate and the annular beads of the base is taught by neither D5 nor D14 so their combination cannot yield the claimed gasket.

Secondly, even if one were to assume that D5 did teach the non-superposition then there is no reason to believe that the skilled person would retain this non-superposition when the cylinder bores were more closely spaced. While, as respondent II pointed out, claim 1 of the main request does not specify the spacing of the cylinder bores, the board considers that it is implicit that these are closely spaced since otherwise there would be sufficient room to provide separate beads between the bore holes. With limited space and in order not to reduce the bead width of the width of the folded portions he might decide to overlap the bead and folded portions.

Thirdly, if the skilled person is producing a gasket for an engine with closely spaced cylinder bores then he might be expected to start from a gasket with closely spaced bores (e.g. D14) instead of a gasket for an engine with wider spaced cylinder bores with water jackets therebetween (D5). As D5 teaches him neither the non-superposition of folded portions and beads nor closely spaced cylinder bores, there seems to the board no reason for him to start from this document at all.

7.7. Thus for the reasons set out in the above sections 7.1 to 7.6 the board does not find that it would have been obvious for the skilled person starting from D5 to arrive at the subject-matter of claim 1 of the main request.

8. Inventive step - claim 1 of the main request - starting from D14

8.1. As explained in section 5 above, one difficulty that the board has with this document is to determine what it actually discloses. It is the task of respondent I who wishes to rely on this document to satisfy the board as to its disclosure.

8.2. As stated in section 5.4 above, it is only Figure 3(d) of D14 that seems to show a folded member on that side of another member from which the bead projects but this bead apparently directly faces not the folded member but an intermediate member and is not in contact therewith. When squashed the gasket the bead would contact the intermediate member and not the folded member.

Respondent I argues that gaskets with any number of layers are commonly known and that the skilled person chooses the number of such layers and their configuration according to his requirements. Thus if he wanted to use the D14 Figure 3(d) gasket for a smaller cylinder head to block gap he would keep the same base member and the same bead dimension and vary the gasket thickness by the number of layers he employed. Thus it would be obvious for him to modify the Figure 3(d) gasket by removing the afore-mentioned intermediate member so that upon squashing the bead would contact the folded member.

While the board can accept that the skilled person could have carried out this modification to the Figure 3(d) gasket, the board cannot see that he would have done so, see the decision T 2/83 (OJ EPO 1984, 265 - "could-would approach"). The board cannot see anything - in D14 or elsewhere - that would motivate the skilled person to make the modification specifically to the Figure 3(d) gasket (instead of perhaps choosing one of the other three constructions shown in Figures 3(a), (b) and (c)).

8.3. In the oral proceedings respondent I discussed "the general practice and common knowledge in the art". However, while it is possible that the points made were known to the skilled person at the priority date, the board cannot be sure that they were not merely internal state of the art and so not in the public domain. In such cases, particularly when the proprietor disputes the availability of such information, it is the task of the opponent to provide evidence for the points it is making. Respondent I has failed to do this.

Moreover respondent I discussed the many possibilities available to the skilled person but failed to present a logical, unbroken chain of reasoning leading to the claimed subject-matter and why the skilled person would adopt specifically the claimed features out of these many possibilities.

8.4. Thus the board does not find that it would have been obvious for the skilled person starting from D14 to arrive at the subject-matter of claim 1 of the main request.

9. There are other documents on file which were cited during the opposition proceedings but which were not mentioned anymore during the appeal proceedings. These are no more relevant than the documents discussed in the appeal proceedings or they merely repeat points made by the documents in the appeal proceedings.

10. Thus the subject-matter of claim 1 of the main request involves an inventive step as required by Article 56 EPC.

11. The patent may therefore be maintained amended, based on claim 1 of the main request, the claims dependent thereon, the partially amended description and the drawings.

12. It is therefore unnecessary to consider the appellant's auxiliary request.

ORDER

For these reasons it is decided that:

1. The decision under appeal is set aside.

2. The case is remitted to the first instance with the order to maintain the patent on the basis of the appellant's main request, i.e. in the following version:

- claim 1 of the main request as submitted in the oral proceedings before the opposition division,

- claims 2 to 8 as granted,

- columns 1 to 2 and 5 to 13 of the description as granted,

- columns 3 and 4 of the description as submitted in the oral proceedings before the board of appeal, and

- the drawings as granted.

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