35 USC 112, 6th paragraph – “An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.”
Means or Step Plus Function – Although the use of the term “means” or “means for” is often a clear indication that the means or step for function rules apply, the actual determination is base coin whether the element in the claim is set forth, at least in part, by the function that it performs rather than the specific structure, material or acts that perform the function.
The examiner has the initial burden of finding a reference containing both the same function and same supporting structure, materials or acts as the applicant’s claim.