T 0378/86 (Change of category) of 21.10.1987

Summary of Facts and Submissions

I. European patent No. 027 575 comprising six process claims was granted on 12 October 1983 for the subject-matter contained in European patent application No. 80 105 926.2 filed on 30 September 1980. Omitting two words in the German version which have no meaning, Claim 1 reads as follows: "A method for controlling the output quantity of an extruder with a two or more part blow die, in which a pre-shaped blank forced out of a pressure head is expanded into the desired hollow body, wherein the blow die is actuated after the pre-shaped blank has reached its nominal length and the blow die is ready to be actuated, and wherein the output quantity is controlled such that the nominal length of the pre-shaped blank is reached at a time after the blow die is ready to be actuated, characterised in that a value is used as a control deviation in dependence on its size and sense the amount of which corresponding to the time difference between the ready time of the blow die (FB) and the time at which the pre-shaped blank reaches its nominal length (LS) in addition to an adjustable shape observation time (5)."

II. The appellant and a further opponent (Opponent 02) filed notices of opposition to the granted patent, requesting that it be revoked on the grounds that the subject-matter of Claims 1 to 6 is not patentable.

III. The Opposition Division issued an interlocutory decision on 26 September 1986 maintaining the European patent in amended form and changing the claim category.

IV.The appellant filed an appeal against this decision and paid the relevant fee on 14 October 1986 and submitted a statement of grounds dated 22 January 1987 which was received on 24 January 1987.

The appellant requests that the contested interlocutory decision be set aside and the patent revoked in its entirety. In the statement of grounds the appellant states that Claim l's subject-matter is not new vis-à-vis DE-B-2 544 171 and that the question of whether the change made in the claim category is admissible is less important than the fact that the claims as granted have been inadmissibly amended in the claims on which the contested decision was based.

V.The Board of Appeal introduced US-A-4 094 620 into the proceedings of its own motion (Art. 114 (1) EPC).

VI. In oral proceedings on 21 October 1987 the respondent (patent proprietor) requested that the patent be maintained on the basis of the Claims 1-6, description and Figure 1 of the drawing as handed over during those proceedings, together with Figures 2 and 3 as contained in the patent specification. The current independent Claim 1 reads as follows:

"Apparatus for controlling the output quantity of an extruder with a two or more part blow die in which a pre-shaped blank forced out of a pressure head is expanded into the desired hollow body, which apparatus actuates the blow die after the pre-shaped blank has reached its nominal length, controls the output quantity such that the nominal length of the pre-shaped blank is reached at a time after the blow die is ready to be actuated, uses a ready time signal (FB) and a light barrier signal (LS) occurring when the pre-shaped blank has reached its nominal length for changing the extruder's speed and includes an adjustable delay device (5) for the ready time signal and a device determining the time difference between the occurrence of the delayed ready time signal and the light barrier signal (LS), characterised in that the value resulting from the difference between the delayed ready time signal and the light barrier signal (LS) represents depending on its size and sense the scale for adjusting the extruder's drive, irrespective of whether the FB or LS occurs first, and a device (8a) is provided for which ensures, again irrespectìve of the order in which the two signals (FB and LS) occur, that the blow die is closed only when the blow die is itself ready and the pre-shaped blank has reached its nominal length." ...

Reasons for the Decision

1. The appeal complies with Articles 106 to 108 and Rules 1 (1) and 64 EPC, and is therefore admissible.

2.The current Claim 1 differs from the claim as granted in that

- the claim category has been changed (process - apparatus) and

a) a device is provided for which ensures, irrespective of the order in which the ready time and light barrier signals occur, that the blow die is closed only when the blow die is itself ready and the pre-shaped blank has reached its nominal length;

b) the proportional control of the extruder's speed takes place irrespective of which of the two above-mentioned signals occurs first;

c) an adjustable delay device is foreseen for the ready time signal, together with

d) a device which determines the time difference between the occurrence of the delayed ready time signal and the light barrier signal.

3.The admissibility of these amendments is examined below:

3.1 Change of Claim Category

3.1.1 Article 123 (3) EPC stipulates that the claims of a European patent "may not be amended during opposition proceedings in such a way as to extend the protection conferred". In the absence of any other provision, the Board is obliged pursuant to Rule 66 (1) EPC to examine the admissibility of the change of category during the appeal proceedings having regard to Article 123 (3) EPC.

3.1.2 The extent of protection conferred by a European patent is determined by the terms of the claims, although the description and drawings are to be used to interpret the claims (Article 69 (1) EPC). Moreover, for reasons of legal certainty, the claims should be interpreted according to objective criteria. The subject-matter defined in the claims should therefore be interpreted as the average skilled person would inevitably understand it based on his own knowledge and skill and taking into account the description and drawings.

3.1.3 Protection has been inadmissibly extended within the meaning of Article 123 (3) EPC when it is obvious that an act can be considered as an infringement after a claim has been amended although prior to the amendment it could not have been considered as an infringement of the patent as granted. This would in all likelihood always be the case where the amended claims and the granted claims are directed to different subject-matter ("aliud").

3.1.4 The division of patents into various categories (process or product) is legally important because the extent of protection depends to a crucial extent on the category selected, specific types of use being allocated to each category which in some cases differ substantially from each other. The difference in effect on the right conferred by a patent is the reason why it is at all justifiable to classify patents in categories.

3.1.5 From the foregoing it is clear that a change of category during opposition proceedings is not generally in keeping with the provisions of Article 123 (3) EPC and is therefore probably inadmissible because it usually means that the amended claims and the granted claims protect different subject-matter (see 3.1.3 above). However, rare cases arise where claims do not protect an aliud despite a change of category. Such exceptions will probably always occur when it is obvious that the granted patent's teaching has been classified in an inappropriate category because the title inaccurately reflects the nature of the invention. There will probably also be instances, particularly having regard to the provisions of Article 64 (2) EPC, where the product claim of a granted patent can be limited in opposition proceedings to a product use defined therein, since the extent of protection conferred by a product patent encompasses that conferred by a use patent. Moreover, it may also be admissible as an exception to convert a process patent into an apparatus patent (see 3.1.6 below).

3.1.6 It is natural for there to be a close inter-relationship between a process and the apparatus suitable for carrying it out. In the case of an apparatus patent the protected apparatus's method of operation and its use as a means of implementing a specific purpose are both of prime importance. To define apparatus clearly and unmistakably it is therefore sometimes necessary to include process features in an apparatus claim. Conversely, some inventions are fully disclosed to an average skilled person as a process only when the definition also refers to features of the apparatus. And in view of the close inter-relationship referred to above it may well be possible in some borderline cases for the invention for which protection is sought to be categorised with the same inventive features as both process and apparatus. Such borderline cases would, for example, always arise when in a process patent the means of carrying out the process are described in such detail and so comprehensively that an average skilled person is able, without undue effort, to deduce fully and clearly the apparatus suitable for carrying out the protected process from the technical teaching defined in the patent. This would mean, however, that in this case the extent of protection (cf. Article 69 EPC) conferred by the process patent also encompasses the apparatus for carrying out the process. Consequently, in these circumstances the conversion of a granted process patent into an apparatus patent would not contravene Article 123 (3) EPC.

3.1.7 In the case in suit the granted patent related to a process for controlling an extruder's output quantity. This process involved a method of working, which is usually understood to mean the action by which operating steps are performed, without it being the purpose of the method (as with methods of production) to change the object being treated. These working or operating steps are usually dependent on the function involved. It must be added, however, that even the apparatus suitable for carrying out a method of working may sometimes be definable only in terms of functional features. In view of this fact the question arises in the case under review whether the invention protected in the granted patent could be assigned with the same inventive features both to the category of process and to that of apparatus for carrying out that process (see Section 3.1.6 above).

3.1.8 All the features set out in the granted Claims 1 to 6 represent functional features, defining process steps linked at least indirectly to specific apparatus features. The latter are in turn functionally linked to each other. It is therefore the Board's view that, based on his knowledge and with the help of the information contained in the granted patent's description and drawings, an average skilled person can readily deduce the apparatus suitable for carrying out the protected process from the technical teaching defined in that patent. The extent of protection conferred by the granted process patent thus encompassed also the apparatus for carrying out the protected process. The question raised (at the end of Section 3.1.7 above) must therefore be answered in the affirmative.

3.1.9 The amendment to the granted Claim 1 made during the opposition proceedings was intended to differentiate the protected invention more clearly from the state of the art. Apparatus features (in the form of product features) were therefore incorporated into Claim 1 which hitherto had merely been disclosed in the description as belonging to the invention. It can be concluded from this that it would be more appropriate for the invention protected in the granted patent to be defined as apparatus. From this angle a change of category had to be considered a necessity.

3.1.10 It follows that the change of category made during the opposition proceedings is compatible with the provisions of Article 123 (3) EPC and is therefore admissible.

3.1.11 Although the category change can be upheld in this case, this must not obscure the fact that, having regard to Article 123 (3) EPC, a change is admissible after grant only in exceptional cases. The requirement to provide legal certainty means that extremely rigid criteria must be set for changing the category after grant of the patent.

3.2 Other amendments to Claim 1 ....

3.3 The protection conferred by the claim has therefore not been extended by the amendments made to Claim 1 as granted.

3.4 The content of Claims 2 to 6 corresponds to that of dependent Claims 2 to 6 as granted.

3.5 Claims 1 to 6 therefore satisfy the requirements of Article 123 EPC. ... The Board's examination of this state of the art also shows that Claim l's subject-matter is new vis-à-vis the other documents referred to during the proceedings. Nor has the appellant contested this. It is therefore unnecessary to go into the matter further here.

8. The following relates to the question of whether the apparatus according to Claim 1 is obvious: ...

9. Claim l's subject-matter therefore involves an inventive step (Article 56 EPC). ...

12. Since in this case the expert representing the appellant could assess the importance of the amendments made to the description, Figure 1 and claims and the representative did not indicate at the oral proceedings that he required more time to consider the matter, it was unnecessary to issue a communication in accordance with Rule 58 (4) EPC (cf. Decision T 219/83, OJ EPO 1986, 211).

ORDER

For these reasons, it is decided that:

1. The contested decision is set aside.

2. The case is remitted to the department of first instance with the order that European patent No. 27 575 be maintained in the following form: