What are the implications of narrowing claims for the written description requirement?
Narrowing claims by introducing elements or limitations not supported by the as-filed disclosure can violate the written description requirement. The MPEP 2163.05 states:
“The introduction of claim changes which involve narrowing the claims by introducing elements or limitations which are not supported by the as-filed disclosure is a violation of the written description requirement of 35 U.S.C. 112(a) or pre-AIA 35 U.S.C. 112, first paragraph.”
However, changes involving subgeneric terminology may be acceptable if the original disclosure provides support. Each case must be evaluated based on what is reasonably communicated to those skilled in the art.
For example, in Ex parte Ohshiro, claims to an engine with “at least one of said piston and said cylinder (head) having a recessed channel” were rejected when the application only disclosed a channeled cylinder head, not a channeled piston.
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