One of the first rules often taught to a young patent attorney, especially for mechanical apparatus claims, is to avoid inferential claiming, i.e., avoid introducing a new element in the middle of a recitation of another element. This type of drafting can lead to ambiguity about whether this new term is positively recited, and thus part of the claimed invention. The PTAB reinforced this lesson in Ex parte Joseph L. Sullivan, Appeal 2014-005800 (PTAB June 22, 2016).
The claim language at issue is “a defibrillation port for guiding via electrodes the stored external charge to a person.” The Examiner rejected this language as being indefinite under 35 U.S.C. § 112, second paragraph. Specifically, the Examiner stated that the phrase “guiding via electrodes” is indefinite because the phrase “is inferentially included and it is unclear if the applicant is positively reciting or functionally reciting the element.” The Examiner also stated that the claim has “not specifically stated the role of the electrodes prior to relying on them for use with the defibrillation port and delivery of electrical charge.”
The Appellant appealed this rejection, and the PTAB upheld the rejection. The PTAB decision stated that “[w]e agree with the Examiner that the claim language ‘a defibrillation port for guiding via electrodes’ is reasonably construed as inferentially reciting a structural element, resulting in uncertainty as to whether the claimed ‘electrodes’ are part of the apparatus as defined by the claims.” It is noted that it does appear that the fact that the language at issue is included with functional language may have affected the panel’s decision. The decision specifically noted that the introduction of the electrodes “in the middle of a functional recitation detailing the function of another structural element” renders the claim scope vague. However, as noted at the conclusion of this post, avoidance of “unintentional” inferential claiming eliminates the potential of running afoul of this type of decision.
Additional discussion of the avoidance of inferential claiming may also be found in Faber on Mechanics of Patent Claim Drafting, Seventh Edition § 3:3.
Lessons for Practice
In an apparatus claim, an inferentially claimed element may be indefinite. While inferential claiming may have its place when deliberately used in specific circumstances, it can often be avoided in apparatus claims with mere word-smithing. The risk of an element being interpreted inconsistently with the intent of the drafter can be eliminated in apparatus claims by avoiding inferential claiming when possible.