BPAI affirms obviousness because airbag inflatable to a graphically determined pressure does not structurally distinguish over any other airbag

Takeaway: In Ex parte Bayley, the BPAI affirmed an obviousness rejection because "an airbag inflatable to a first pressure  ...  determined from a graph that plots pressure versus thickness" did not distinguish the airbag from any other airbag. The BPAI found that the pressure determination limitation was not a structural limitation, and thus did not give it patentable weight.

Details:
Ex parte Bayley
Appeal 2009008110, Appl. No. 11/175,731, Tech. Center 3600
Decided October 21, 2010

The claims were directed to a vehicle airbag system. The limitation at issue (emphasized below) related to the pressure used to inflate the airbag.

19. A system for helping to protect an occupant of a vehicle ... said system comprising:
     an inflatable vehicle occupant protection device  ... ; and
     an inflation fluid source actuatable to provide a volume of inflation fluid to said inflatable volume sufficient to inflate said inflatable vehicle occupant protection device to at least a first pressure,
     said first pressure being determined from a graph that plots pressure in said inflatable vehicle occupant protection device versus said thickness of said inflatable vehicle occupant protection device ...

The Examiner rejected claim 19 as obvious. The Examiner relied on one reference to teach a relationship between inflation pressure and airbag thickness, and another reference to teach all the other elements.

The Examiner indicated that no patentable weight was given to using a graph to determine the inflation pressure. The Examiner characterized this use of a graph as merely “an intermediary step in a design process” and “not germane to the patentability of the apparatus because there is no structure that is imparted by the design step that distinguishes the airbag claimed from the prior art airbag.”

In the Appeal Brief, the Applicant argued that the graphically determined inflation pressure was a structural rather than a process limitation and should therefore be given patentable weight. Specifically, the Applicant argued that the limitation of a “graphically approximated pressure” should be interpreted as a structural limitation because it defines the pressure of the inflation device, which is “an objectively observable characteristic of the device.” According to the Applicant, the relationship embodied by the graph “imparts upon the protection device a particularized inflation pressure depending on the thickness of the airbag.”

The Applicant went on to explain similarities between the limitation of claim 19 and other types of limitations, all of which the Applicant said were structural:

     Claim 19 recites the structural limitation of a pressure that is determined graphically. More specifically, the structure recited in claim 19 is that of a protection device and an inflator that provides a volume of inflation fluid sufficient to inflate the protection device to at least a first pressure, the magnitude of which is approximated from a plotted point on a graph that plots the inflated thickness of the protection device versus the inflated pressure of the protection device. This structure cannot be described in any other way and therefore must be given patentable weight.
     The scope of this claim element is no less structural, and therefore no less germane to patentability, than a recitation of a specific pressure (e.g., 20 psi/g), a specific formula (e.g., pressure equal to a mathematical formula based on thickness), or a specific function (e.g., a pressure sufficient to prevent an object from striking through the inflated thickness of the protection device).

The Board was not persuaded, deciding that "an inflation pressure value determined from a plot of inflation pressure versus airbag thickness" was not a structural limitation. Referring to the Appeal Brief's list of alternative ways to express the function of inflating, the Board explained that:

Appellants have not provided any evidence to show that an airbag having an inflation pressure chosen from a plot of inflation pressure versus airbag thickness is any different structurally from an airbag having an inflation pressure chosen from a table of inflation pressures and airbag thicknesses or an airbag having an inflation pressure and airbag thickness derived experimentally. An attorney's arguments in a brief cannot take the place of evidence. In re Pearson, 494 F.2d 1399, 1405 (CCPA 1974).

The Board then affirmed the obviousness rejection.

My two cents: I think the Board's point – the airbag in the claim is not different than the airbag in the reference – is very important. But it's also subtle. The distinction (presumably) is the actual mechanism used to inflate to the desired pressure –  but that mechanism wasn't actually claimed.

What's going on here is what I call "inferential claiming." The Applicant claimed around the mechanism for inflating to a desired pressure, by referring to an inflation value that was determined in a specific way (a graph). But the claim did not expressly recite the mechanism.

How should the claim have been drafted? Let's assume that software running on a processor determined the desired inflation pressure based on airbag thickness. Then the claim should recite the processor as a structural element, and use functional language to describe how the processor controls the inflation. Maybe even throw in more structure, in the form or an actuator or valve, controlled by the processor. 

Now, I'm not suggesting that my improved claim is patentable over the references. If you throw in a reference that teaches processor-controlled inflation, the Applicant's inflation mechanism may well be obvious in light of the relied-upon reference that taught a relationship between thickness and pressure.

What I am saying is it's a really good idea to make sure the novel mechanism is actually expressed in the claim.

I'll mention one more criticism I have of the claim as written: the use of "a graph" in the claim. The way I see it, the software doesn't literally use a graph to determine inflation values. A table, maybe. A graph, no. So I'd stay away from "graph" and claim the software using a functional relationship between pressure and thickness.