No matter how many times examiners try to ignore exact limitations (like single, only one, exactly one, etc.) because the claims use an open-ended transitional phrase between the preamble and body, examiners are consistently reversed. While this issue still depends on some of the facts of the case, the USPTO needs to do some training with the examining corp to reduce these issues having to be appealed to the PTAB. The most recent example is Appeal 2020-001003, Application 14/783,510.

Claim 1 on appeal relates to a hand held olfactory tester comprising, among other things:

an elongated housing having a forward portion and a rear portion…; and
a single odorant chamber located within said forward portion and containing an odorant therein…

The examiner relied on prior art that admittedly did not have a single chamber, but rather multiple chambers. Specifically, the examiner argued that Claim 1 does not require that there only be a single odorant chamber within the housing because it recites “A hand held olfactory tester comprising ... a single odorant chamber”. The examiner’s reasoning cited MPEP 2111.03 I explaining that, “comprising” is a transitional phrase that is “inclusive or open-ended and does not exclude additional, unrecited elements or method steps”. The Office noted that by having a plurality of chambers, as taught by the cited art the limitation of the apparatus ‘comprising’ a single chamber is met.

As a past post explained (https://www.mriplaw.com/blog/hnk2vc1foer6jt86kwthc6dnwvrfth), transitional phrases do not reach down into the body and “undue” explicit limitations. One does not need to use a “consisting of” transition in order to limit one of the claimed elements.

Back to the odorant chamber, the PTAB quickly dismissed the examiner’s reasoning (internal citations omitted):

“During examination, ‘claims ... are to be given their broadest reasonable interpretation consistent with the specification, and ... claim language should be read in light of the specification as it would be interpreted by one of ordinary skill in the art.’” The term “comprising,” when used in the preamble of a claim, permits the inclusion of other elements or materials in addition to those specified in the claim. Although it is “acknowledge[d] that the term ‘comprising’ raises a presumption that the list of elements is nonexclusive, . . . ‘[c]omprising’ is not a weasel word with which to abrogate claim limitations.’” “The presumption raised by the term ‘comprising’ does not reach into each of the [elements] to render every word and phrase therein open-ended” (id.), and must be read in view of the Specification

Here, we agree with the Appellant that the ordinary and customary meaning of the term “single” is “one and only one.” The Specification is consistent with this meaning (1) differentiating the Appellant’s tester capable of being administered using one hand and having a chamber and thumb engagable member from the prior art “Sniffin’ Sticks” having “a number of tubular odorant chambers” whereby two hands are needed to administer the test, (2) describing a housing with “an odorant chamber,” (3) consistently referring to “the odorant chamber,” (4) describing the cylinder as “having a chamber 22 therein,” and (5) depicting the device with only one chamber. Although the preamble of claim 1 provides for a “tester comprising” the listed elements, the term “comprising” as used in the preamble does not reach into the element of a single chamber to negate the meaning of single as understood by one in the art, and as indicated in the Specification, as consisting of one and only one.

So, we see here, again, factors to be considered include not only the plain and ordinary meaning (e.g., via a dictionary) but also whether the specification is consistent with the plain meaning, including differentiating prior art via problem/solution, referring to the element in a way that it consistent with the plain meaning, and using figures that correspond to the plain meaning.