Even if the law regarding patents were simple and straightforward (which it is not), patent issues are still exceedingly difficult because who wins or loses often depends on the meaning of even the most basic words that, ordinarily, would seem perfectly clear and unambiguous. And for someone who is intent on creating roadblocks, the opportunity for sowing uncertainty is often too great to resist.

Take a recent PTAB appeal regarding the term “bypass”. Everyone knows what a bypass is, right? But under the Broadest Reasonable Interpretation, examiners often overreach and interpret things in a way to include what one would think is the opposite of a bypass.  In this case, the issue relates to a transmission cooler configuration of a vehicle. A simplified version of the claim elements at issue was that the claimed method required: (1) directing a fraction of a coolant leaving the coolant pump to the propulsion system and subsequently back to the coolant pump; and (2) directing a remainder of the coolant leaving the coolant pump to the transmission cooler and subsequently back to the coolant pump, bypassing the propulsion system. 

The prior art had a bypass, but of course not to the transmission cooler.  FIG. 1 of the prior art (anticipation) reference is below:

The Examiner asserted that the split at the thermostat 17 (into lines 18 and 20) counted as a bypass around the propulsion system 6 according to the claim language because line 20 to the transmission cooler “bypasses” the propulsion system 6 when traveling from the thermostat 17 to the coolant pump 1. The applicant argued that the coolant from the engine goes through both lines 20 and 18 and so the claim limitations are not met.

The PTAB agreed with the applicant, noting that it was incorrect so say that fluid directed by thermostat valve 17 to transmission oil cooler 24 and then to coolant pump 1 bypasses element 6. Instead, fluid flowing to thermostat valve 17 also passes through the propulsion system 6 after it leaves coolant pump 1. After exiting system 6, it flows to thermostat valve 17 via flow line 10 and cooling circuit 11.

Here, one would have thought the proper lines to consider for a bypass was the one with oil cooler 15. But not this examiner (who incidentally is in art unit 3747) - instead the applicant was forced to spend many thousand of dollars and incur years of delay because of an unreasonably broad interpretation of what in reality is quite simple and straightforward language.

As claims are made of many words (historically the number of words per independent claim is somewhere around 175 (citation)), one can imagine how difficult things can be since virtually every word of a patent claim can lead to these types of issues - even words like “on” or “in”.

So, do your best to anticipate such overly-broad interpretations and provide support in the specification that is consistent with the intended meaning and scope. These issues tend to occur mostly in the mechanical arts, confirming why mechanical cases really can be more challenging than your average patent case, at least from a legal strategy point of view. Perhaps examiners in software cases do not need to worry as much about such issues since they have such a potent weapon with Section 101 rejections, at least in recent years.