PTAB Applies Precedential Opinion: Broadest Reasonable Interpretation Excludes Conditional Limitation

Here is an important reminder that so-called conditional claim limitations may not be accorded patentable weight, i.e., may be useless in arguing against a patent examiner’s prior art rejections.  In applying a precedential PTAB opinion, a PTAB panel recently affirmed an examiner’s rejection stating that a patent claim was obvious over a combination of references, even though the combination did not teach a conditional claim limitation. Ex parte Christopher J. Gibbings; PTAB Appeal 2015/004458 (December 8, 2016).

Independent claim 27, at issue, reads:

A method for routing data, the method comprising:

detecting that a link has failed in a parallel link configuration;

determining whether a minimum number of links in the parallel link configuration are operational;

if the minimum number of links I the parallel link configuration are operational, advertising actual metrics associated with the operational links; and

if the minimum number of links in the parallel link configuration are not operational, advertising one or more artificial metrics associated with any remaining operational links in parallel link configuration.

The Examiner rejected this claim as being obvious over a combination of two references. The Appellant argued that this combination of references failed to teach or suggest “if the minimum number of links in the parallel configuration are not operational, advertising one or more artificial metrics associated with any remaining operational links in the parallel link configuration.”  The PTAB panel concluded that, “[a] conditional method step generally does not need to be performed under the broadest reasonable interpretation of the claim, which encompasses instances in which the method ends when the prerequisite condition for the step is not met.”

In reaching this conclusion, this PTAB panel relied on a precedential PTAB decision from 2016, Ex parte Randal C. Schulhauser; Appeal 2013-007847 (April 28, 2016).  The Schulhauser panel reasoned that conditional steps need not be performed if the condition precedent is not met.  Said differently, a claim with conditional steps theoretically claims two methods: 1) a broader method that does not include the conditional steps when the condition precedent is not met, and a narrower method that does include the conditional steps when the condition precedent is met.  Thus, when construing this claim, the broadest reasonable interpretation of such a claim does not include the conditional steps.  Accordingly, a combination of references need not teach or suggest a conditional limitation for the claim to be obvious over the combination.

Lessons for Practice

The lesson here is both obvious and extremely difficult to practice in every case, especially in the world of software patent applications: avoid conditional claim limitations wherever possible.

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