Claims are single-sentence, numbered paragraphs found at the end of the patent specification. The claims define the boundary of the invention. Each claim defines a separate invention, and they may be an independent claim or a dependent claim.
Figure 1 is an example of a claim. Each claim includes a preamble, a transition phrase and a body.
The preamble can be as narrow or as broad as desired. Sometimes the preamble is as simple as “an apparatus” or “a method” for performing some function. Sometimes it is very narrow, however, such as “an aluminum alloy.”
There is conflicting authority with respect to the role of the preamble in defining the scope of a claim. An examiner will usually ignore the preamble unless the patentee relies upon the preamble to get around prior art. However, some courts do not overlook the preamble and use it to construe the scope of a claim.