T 0629/90 (Holding device) of 4.4.1991

Summary of Facts and Submissions

I. The appellant is proprietor of patent No. 0 077 050.

II. The grant of the patent was opposed by two companies:

- Schuntermann & Benninghoven GmbH, D-4010 Hilden, and

- Talema Elektronik GmbH, D-8034 Germering,

which both requested that it be revoked on the grounds that its subject-matter lacked inventive step.

Both opponents substantiated their request by referring to the state of the art as disclosed in various documents and also in toroidal transformers in prior public use.

One of the opponents, Talema Elektronik, withdrew its opposition before the Opposition Division delivered its decision. However, the Office continued to take account of evidence which had been cited and/or presented by Talema Elektronik during the proceedings.

The Opposition Division revoked the patent by a decision dated 30 May 1990.

That decision was influenced by the following pieces of evidence which had been cited and/or presented by the opponent Talema Elektronik during the proceedings:

E1: Brochure entitled "Ringkern-Bauelemente" issued by Talema Elektronik in October 1979

E2: DE-U-7 403 951, corresponding to FR-U-2 260 269

E3: DE-U-6 914 319

E6: Delivery note No. 6 101 dated 31 August 1981

E8: Drawing No. 3 403-P1S5 of a special holding device, dated 29 June 1981

E9: Affidavit by Mr Erwin Tischer, dated 26 January 1989, in conjunction with two pages from a despatch list.

III. The patent proprietor appealed against the Opposition Division's decision.

IV. In a communication of 10 January 1991 accompanying an invitation to oral proceedings, it was pointed out that the Board too regarded the documents cited by the Opposition Division in its decision as the most important indicators for judging inventive step; to a certain extent, however, common general knowledge in the relevant field also had to be taken into account. This included the toroidal variable transformers in the catalogues adduced by the opponent Schuntermann & Benninghoven.

V. Schuntermann & Benninghoven also withdrew its opposition before oral proceedings took place.

VI. Oral proceedings were held on 4 April 1991.

The appellant (patent proprietor) requested that the decision under appeal be set aside and the patent maintained as granted.

VII. Independent Claim 1 reads as follows:

"1. Holding device made of plastic material for toroidal cores provided with windings, consisting of a carrier member (2) which fits the external diameter of the wound toroidal core (1) and has a central centering pin (3) projecting into the interior of the toroidal core and preferably formed as a hollow cylinder, to which the wound toroidal core is fixed by means of sealing material (4), characterised in that the carrier member (2) is formed as a circular plate with means (12) serving to prevent the holding device from slipping relative to a support (15) when the holding device is fixed to the said support."

VIII. When revoking the patent the Opposition Division argued that the essential features of Claim 1 formed part of the state of the art as disclosed through the supply of the 50 special holding devices shown in Talema Elektronik's document E8. That disclosure had not been contested. In the remaining features - the circular retaining plate with means to prevent it from slipping relative to a support - the Opposition Division found no evidence of inventive step.

IX. During the opposition proceedings, the appellant did not dispute the prior public use of toroidal transformers according to delivery note 6 101 (citation E6) with a special holding device as per drawing 3 403-P1S5 (citation E8). In its statement of grounds for the appeal, however, it argued that the prior public use had not served as a stimulus in the same way as its own invention, since the transformer in question had a relatively high capacity (938 VA) whereas its invention was essentially a mass-produced item of considerably lower capacity, intended for use as a decoupling device in telecommunications equipment or for inputting data in remote computer systems. The special holding device depicted in E8 was designed so that the toroidal core could only be mounted horizontally. No such restriction applied to the holding device according to the invention.

At the oral proceedings, the appellant's representative added that the drawing of the special holding device 3 403-P1S5 submitted by the opponent Talema Elektronik included no measurements whatever and could scarcely have served as a construction drawing. That the device had been supplied was not in doubt, but that it had been manufactured on the basis of the drawing had not been definitely established.

In the appellant's view, the invention offered the following advantages compared with the usual types of holding devices for toroidal transformers, in which the wound toroidal core was sandwiched between two mounting plates (E1) or entirely sealed in a ring-shaped trough (E1 and E2):

- constraint-free attachment (no pressure on the winding from mounting components)

- efficient heat dissipation (the sealing material only partly enclosed the winding)

- tolerance limits in winding the toroidal core were higher than if the core were sealed in a ring-shaped trough

- the holding device could be attached in any position required

- the circular shape of the carrier member saved space

- slippage was prevented (e.g. by two notches in the circular plate).

The simple solution of a pressure-free holding device had also been a surprising commercial success, and this was a further argument in support of patentability.

Reasons for the Decision

1. The appeal is admissible.

2. Procedural questions

2.1 As mentioned above (point V), the opponent Schuntermann & Benninghoven GmbH withdrew its opposition in a letter dated 7 March 1991. It did not participate in the subsequent appeal proceedings. This gives rise to the following comments on the relevant procedural law:

2.2 Whereas under Rule 60(2) EPC opposition proceedings may be continued at the discretion of the European Patent Office when the opposition is withdrawn, withdrawal of the opposition in appeal proceedings has no immediate procedural significance if the Opposition Division has revoked the European patent. The Board of Appeal must then re-examine the substance of the Opposition Division's decision of its own motion, setting it aside and maintaining the patent only if the latter meets the requirements of the EPC. When the Board examines the decision, evidence may be cited which had been submitted by an opponent before the opposition was withdrawn.

3. Novelty

In terms of features, the special holding device in prior public use to which the subject-matter of Claim 1 approximates most closely is that shown in drawing 3 403-P1S5 (E8) with the toroidal transformer mounted on it.

3.1 In view of the evidence submitted to the Opposition Division by the opponent Talema Elektronik, the appellant has not disputed the public character of this prior use. The delivery note (E6) dated 31 August 1981 clearly cites the number of the drawing (E8) submitted in evidence. There is no reason to doubt that the delivery to Münch GmbH in Mannheim did indeed take place (cf. E6 and point 2 of E9, the affidavit from Mr Tischer dated 26 January 1989). Nor is there any evidence of an intention to keep the design of the toroidal transformers secret, details of which are readily inferable.

3.2 During the oral proceedings the appellant expressed doubts about the drawing (E8) adduced by the opponent, alleging that, as it contained no measurements, it did not document all the details of the holding device actually supplied. If the drawing is scrutinised in conjunction with the affidavit (E9), however, the following basic design features can clearly be inferred:

The known holding device for a toroidal core provided with windings (transformer 1) is composed of a carrier member formed as a circular plate (retaining plate 2) which, self-evidently, fits the external diameter of the wound toroidal core. The carrier member has a centering pin (centering fixture 3) projecting into the centre of the wound toroidal core, which is fixed to the centering pin by means of sealing material (4).

3.3 By contrast, Claim 1 incorporates the following additional features:

- The holding device is made of plastic material (during the opposition proceedings, the material of the holding device in prior use was not ascertained)

- The retaining plate is circular (whereas the one in prior use is rectangular; cf. point 3 of the affidavit).

- Means are provided for preventing the holding device from slipping relative to a support to which it can be fixed.

- The formation of the centering pin as a hollow cylinder is mentioned as a preferred option only.

4. Inventive step

4.1 Paying due regard to the further state of the art cited by the Opposition Division in support of its decision to revoke the patent, the Board also concludes that the distinctive features vis-à-vis prior public use are non-inventive details.

- The option of using plastic material for the holding device is obvious to the skilled person; according to E1, for example, casings made of plastic (in this case, Macrolon) are available on the market.

- The circular shape suggests itself automatically because of the ring-shaped core, and corresponds, for example, to the form of the ring-shaped trough for the toroidal core shown in E2. Furthermore, circular carrier members are familiar from toroidal variable transformers of the type advertised in the Schuntermann & Benninghoven catalogues.

- If the holding device is fixed to a support by a single central attachment, the provision of means to prevent the holding device from slipping relative to the support is merely a technical expedient. E3 (page 7, lines 6 to 9) contains an explicit reference to an anti-slip feature of this type.

- The proposed optional formation of the centering pin as a hollow cylinder must also be regarded as common practice in the relevant technical field. This is indicated by the embodiments in E2 and the section drawing of a Macrolon casing on page 5 of E1.

Although the individual features are taken from different citations, they are after all very simple constructional contrivances which can be used as described by any average skilled person to exploit their obvious function. They have no further effect in terms of a surprising functional combination.

4.2 The argument, set out in the statement of grounds for appeal, that the invention relates to toroidal cores of considerably lower capacity than the toroidal core in prior public use, is invalidated by the mere fact that Claim 1 of the patent makes no provision for limitation to a particular capacity.

Moreover, all the features of Claim 1 are constructional elements which as a general principle can also be used in the same way for toroidal cores of differing capacity ranges. Varying the thickness of the material according to functional requirements and the size and positioning of the toroidal cores falls within the scope of the designer's normal activities.

4.3 Finally, the "advantageous" effects claimed by the appellant during oral proceedings do not extend beyond the state of the art. Constraint-free attachment of the toroidal core, efficient heat dissipation from it and non-critical tolerance limits are features already incorporated to the same degree in the holding device in prior public use, by virtue of the partially exposed winding. The space-saving circular shape and the anti-slip feature are, as previously stated, familiar from other documents relating to holding devices for wound toroidal cores.

The product's commercial success as claimed by the appellant cannot be regarded as definite evidence of inventive step if, as has been shown, such success is based solely on the application of familiar design principles, exploiting their known effects.

4.4 To sum up, it follows from the arguments set out above that the subject-matter of independent Claim 1 does not involve an inventive step. The appellant's request that the decision of the Opposition Division be set aside and the patent maintained cannot therefore be granted.

ORDER

For these reasons it is decided that:

The appeal is dismissed.