Each new element in a product claim and each new step in a method claim should be first introduced either as:
- the subject of its own clause, or
- a previously introduced and named item or a step comprises it, has it or includes it.
Being the subject of its own clause means that it is either stated in the clause that such an element or step is present, or the element or step is named at the beginning of the clause and thereafter that element or step, which has been named now for the first time, does something or has something done to it. It is important that a new item mentioned for the first time in the claim not be first mentioned as an element operated upon or cooperated with by a previous element described in the same clause.
A new element or step is introduced with an indefinite article “a” or “an.” On the other hand, when a previously identified element or step is repeated, it is introduced by a definite article “the,” “such” or “said.” The indefinite article “a” may be used where it is preceded by either of the words “comprises,” “includes,” “has,” or “being” or the equivalent, which indicates a state of being, rather than some activity involving that element being named.
One should look at the claim to see that each element or step is introduced with an indefinite article. Then note whether that element or step is the subject of the clause or whether it is being acted upon or is itself acting upon another object or step. If it is being acted upon or acting upon another object, then it should be the subject of that clause.
The only exception to the inferential claiming prohibition is where the indefinite article “a” is used to introduce a work piece. Because the work piece is not an element of the claim, but rather is only worked upon by one of the claim elements, it would not be introduced as the subject of its own clause.