Be Careful Deciding What To Put In A Preamble

The preamble of a claim is the introduction portion that usually precedes the "including": or "comprising". In the following claims{fn}U.S.5464681 (Nov.1995)"Replaceable adhesive display"; U.S. 5443179 (Aug. 1995) "Gumball banks".{/fn}, the entire italicized wording is the preamble.

1. A replaceable adhesive display for mounting on a surface, comprising:

(a) a substrate selected from the group consisting of paper, metallized paper, and foil...;

(b) a transparent overlay disposed on at least one of said facings...; and

(c) a pressure sensitive, replaceable adhesive coating applied to said adhesive-enhancing surface, whereby said display can be sealed and unsealed several times on said mounting surface.

1. A gumball bank for dispensing gumballs upon insertion of a coin and for storage of inserted coins, the gumball bank comprising:

a reservoir for gumballs...

a base defining an upper floor...

a dispensing mechanism disposed between the upper and lower floors....

Claims that omit the colon/semicolon formats also have preambles. In the following claim the preamble is "[a]n internal combustion engine having".

1. An internal combustion engine having a compression stroke and a power stroke having fixed lengths, wherein the length of the compression stroke is less than the length of the power stroke.

In general preambles are used to introduce the subject matter, and to recite elements that are not strictly part of the invention. In the example above, the "internal combustion engine" is not part of the invention (at least not of the invention of this claim). The invention is an apparatus in which the crank pin is carried in a pattern that provides compression and power strokes having different lengths.

Method claims also have preambles. In the claim below , the preamble includes all of the language up to the word "comprising".

14. A shielding method for use in an electroplating system, comprising the steps of providing a tank that holds an electrolytic bath solution ...;

positioning a shield assembly...;

positioning a substrate cathode assembly...

moving the positioner bar along said glide bar...;

applying a first voltage...; and

controlling a level of shielding provided by the shield.

One issue that arises in patent prosecution is whether the recited elements of a preamble are interpreted as claim limitations. That can make a huge difference in claim construction, and therefore both patentability and infringement. For example, in the internal combustion engine example cited above, the scope of the claim would be limited to internal combustion engines if and only if the term "internal combustion engine" is construed to be an element of the claim. In this particular case, the term likely would be construed as an element of the claim. The reason is that patentability of apparatus claims must depend upon structural limitations and not upon statements of function. A fuller discussion of this principle is set forth in Chapter IV, section F(1), infra.