What is the difference between preambles in apparatus claims vs. method claims?

The interpretation of preambles can differ between apparatus claims and method claims. The MPEP 2111.02 provides guidance on this distinction:

For apparatus claims:

  • Preambles often recite the intended use or purpose of the apparatus
  • Generally, if the body of the claim fully and intrinsically sets forth the complete invention, the preamble is not considered a limitation
  • Example: “A machine for cutting paper” may not limit the claim if the body describes all structural elements needed for paper cutting

For method claims:

  • Preambles may recite the purpose or intended use of the method
  • They are more likely to be considered limiting if they recite essential steps or structure
  • Example: “A method of treating cancer” may be limiting if the body doesn’t explicitly mention cancer treatment

The MPEP states: “If the body of a claim fully and intrinsically sets forth all of the limitations of the claimed invention, and the preamble merely states, for example, the purpose or intended use of the invention, rather than any distinct definition of any of the claimed invention’s limitations, then the preamble is not considered a limitation and is of no significance to claim construction.

It’s important to analyze each claim individually to determine whether the preamble is limiting, considering the claim type and the relationship between the preamble and the body of the claim.

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Topics: MPEP 2100 - Patentability, MPEP 2111.02 - Effect Of Preamble, Patent Law, Patent Procedure
Tags: apparatus claims, Claim Construction, method claims, Preamble Interpretation