Claims shall be supported by description (Section 25(5)(c))

Inconsistencies – essential features

5.93 A lack of support may arise where there is a serious inconsistency between the description and claims. In particular, the claim should include all of the essential features of the invention in order to be supported. These are the features that have a material effect on the way an invention works. A feature may be considered to be essential if:

(1) it is evident from a reading of the description that a particular feature materially affects the way an invention works;

(2) the description clearly states that a particular feature is essential;

(3) the description says or implies, e.g. by its object clause in the Summary of the Invention, that the features are essential to the invention and cannot be omitted from the claims; and

(4) when a functional clause (e.g. whereby clause) appears in a claim which promises a result to be achieved, then an element required to achieve that result is considered essential.

5.94 Non-essential features are those that have no material effect on the way an invention works. Generally, if there is no working interrelationship, or potential working interrelationship, between a given feature and the other features recited in the claims, then that feature does not usually materially affect the way that the invention works. It is not necessary to set out in the claims all the non-essential elements that may make a combination workable. For example, a claim to an article for conditioning fabrics in a laundry dryer and comprising a flexible woven or non-woven sheet having on it areas of fabric conditioning composition was found to lack support as the description indicated that it was an essential feature of the invention that the material was permeable to air (Glatt’s Application [1983] RPC 122).

5.95 Similarly, a claim may define a particular method of treating “synthetic resin mouldings” to obtain changes in physical characteristics. If all of the examples described related to thermoplastic resins and the method appeared unsuitable for thermosetting resins, then it may be an essential feature of the invention that thermoplastic resins are used. However, it should be remembered that the applicant does not need to exemplify each and every embodiment they claim – in cases such as this it must be clear that the feature is essential to the invention.