Rule 44(1) indicates how one determines whether or not the requirement of Art. 82 is fulfilled when more than one invention appears to be present. The link between the inventions required by Art. 82 must be a technical relationship which finds expression in the claims in terms of the same or corresponding special technical features. The expression "special technical features" means, in any one claim, the particular technical feature or features that define a contribution that the claimed invention considered as a whole makes over the prior art. Once the special technical features of each invention have been identified, one must determine whether or not there is a technical relationship between the inventions and, furthermore, whether or not this relationship involves these special technical features. It is not necessary that the special technical features in each invention be the same. Rule 44(1) makes clear that the required relationship may be found between corresponding technical features. An example of this correspondence is the following: in one claim the special technical feature which provides resilience is a metal spring, whereas in another claim it is a block of rubber.
A plurality of independent claims in different categories may constitute a group of inventions so linked as to form a single general inventive concept. In particular, Rule 44(1) should be construed as permitting the inclusion of any one of the following combinations of claims of different categories in the same application:
However, while a single set of independent claims according to any one of the combinations (i), (ii) or (iii) above is always permissible, a plurality of such sets of independent claims in one European patent application can only be allowed if the specific circumstances defined in Rule 43(2)(a) to Rule 43(2)(c) apply and the requirements of Art. 82 and Art. 84 are met. The proliferation of independent claims arising out of a combined effect of this kind may therefore be allowed only exceptionally.
Moreover, it is essential that a single general inventive concept links the claims in the various categories. The presence in each claim of expressions such as "specially adapted" or "specifically designed" does not necessarily imply that a single general inventive concept is present.
In combination (i) above, the process is specially adapted for the manufacture of the product if the claimed process results in the claimed product, i.e. if the process is actually suited to making the claimed product accessible and thereby defines a technical relationship as defined in Rule 44(1) between the claimed product and the claimed process (see W 11/99). A manufacturing process and its product may not be regarded as lacking unity simply by virtue of the fact that the manufacturing process is not restricted to the manufacture of the claimed product.
In combination (ii) above, the apparatus or means is specifically designed for carrying out the process if the apparatus or means is suitable for carrying out the process and thereby defines a technical relationship as defined in Rule 44(1) between the claimed apparatus or means and the claimed process. It is not sufficient for unity that the apparatus or means is merely capable of being used in carrying out the process. On the other hand, it is of no importance whether or not the apparatus or means could also be used for carrying out another process or the process could also be carried out using an alternative apparatus or means.