Patent claim is lack of antecedent basis is one of the most common problems found in claims of novice patent writers. As per the claim requirements, every element in a claim must be properly introduced before the element can be modified or qualified. For example, the qualification “the upper support” in a claim is improper if the “upper support” has not been previously introduced in that claim or any claim that the said claim is dependent on. Similarly, a statement such as “a wheel mounted on the shaft. . .” is improper if the “shaft” has not been introduced previously in the claim or any claim that the said claim is dependent on. In other words, the definite articles “the,” “said,” and “such” cannot be used unless the following noun has already been introduced in the claim. Whenever a definite article is used in a claim before an element of the claim, the exact same element should be introduced in the claim.
In case of a dependent claim, the antecedent basis should be present in that dependent claim or any claim upon which that claim is dependent, since a dependent claim incorporates all of the claims from which it depends, by reference.
If there are more than one particular elements, the elements should be introduced in plural to limit or distinguish between the elements introduced as a plurality. Therefore, if there are two wheels in an invention, they should be defined in the claims as “two wheels,” or “a plurality of wheels,” or “first and second wheels,” or “at least two wheels,” etc.