How claim wording changes what you own

Why the wording matters

A claim is the statement that sets the limits of your patent. "[T]he name of the game is the claim", as In re Hiniker put it in a passage quoted in the MPEP, the Patent Office's examining manual (MPEP § 2103). The phrase originated with Judge Rich (case digest). The Supreme Court made a similar point long ago: the claim is "a statutory requirement", not "a nose of wax" (White v. Dunbar). Think of it as one sentence with consequences in every word.

The word that opens or closes the door

Comprising is open-ended, consisting of excludes unspecified elements, and consisting essentially of sits between (MPEP § 2111.03). A claim to a lamp comprising a base and a bulb still covers a lamp that adds a shade. A claim to a lamp consisting of those two parts does not.

The opening phrase

The preamble is the introduction before that word. Whether it limits the claim has no litmus test (MPEP § 2111.02). Jepson form, which states what is known and then the improvement, admits the preamble as conventional (37 C.F.R. § 1.75(e)). Use it only if you mean that admission.

Building fallbacks

WIPO advises "a set of claims that ranges from the broadest to the narrowest", with dependent claims as the "fallback" (WIPO Patent Drafting Manual). A dependent claim must include every limitation of its parent and add one (MPEP § 608.01(n)). A multiple dependent claim points to several earlier claims. It may refer to them in the alternative only, and multiple dependents cannot feed one another (37 C.F.R. § 1.75).

Keeping references clear

Introduce each part before you refer back to it. "Said lever" with no earlier lever can be unclear, though scope that is reasonably ascertainable is not indefinite (MPEP § 2173.05(e)). Indefinite means a reader cannot tell what the claim covers.

Why "means" invites trouble

A means-plus-function term names a job instead of a structure. Under section 112(f), "means" plus a function triggers a presumption that this special treatment applies, and a generic placeholder word can do the same. For a function performed by a computer, the specification needs a disclosed algorithm, or the claim is indefinite (MPEP § 2181).