How does MPEP 2144.04 address reversal, duplication, or omission of parts in patent applications?

This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.

MPEP 2144.04 addresses reversal, duplication, and omission of parts in patent applications through specific subsections:

• Reversal of Parts (VI)(A): “The mere reversal of the working parts of a device involves only routine skill in the art.” – In re Gazda, 219 F.2d 449, 104 USPQ 400 (CCPA 1955)
• Duplication of Parts (VI)(B): “The mere duplication of parts has no patentable significance unless a new and unexpected result is produced.” – In re Harza, 274 F.2d 669, 124 USPQ 378 (CCPA 1960)
• Omission of an Element and Its Function (II)(A): “The omission of an element and its function is obvious if the function of the element is not desired.” – Ex parte Wu, 10 USPQ 2031 (Bd. Pat. App. & Inter. 1989)

These legal precedents suggest that reversing, duplicating, or omitting parts in a device or process is generally not considered patentable unless it produces a new and unexpected result or solves a specific problem in a non-obvious way. Patent examiners may use these rationales to reject claims that merely involve such modifications without demonstrating a significant improvement or unexpected outcome.