In the quest to invalidate patent claims, many patent practitioners have found themselves in possession of a base reference requiring the change of an element or two from a teaching reference to arrive at what appears to be a viable combination.  Such was the case in the unpublished Federal Circuit case of Plas-Pak Industries, Inc. v. Sulzer Mixpac AG, No. 2014-1447 (Fed. Cir. Jan. 27, 2015).  Even though this is a nonprecedential decision, it provides a useful reminder to patent practitioners that when combining references, the prior art’s principle of operation or intended purpose can be an important consideration.

The case involved Sulzer’s U.S. Patent No. 7,815,384 (“the ’384 patent”), claiming a device and methods for mixing and dispensing multi-component paints.  As this is a mechanical device, it will help to visualize the device, shown below in Figure 1 from the ’384 patent.

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The claimed device includes, inter alia, two cylindrical cartridges (1, 1a), a static mixing nozzle (9), a spray tip (21), and first and second flexible tubes (12). The apparatus permits the simultaneous mixing, dispensing, and spraying of two-component paints in industrial settings.

Plas-Pak filed an inter partes reexamination request, which was granted, proposing a substantial new question of patentability based on two grounds. The first was that the claims were unpatentable as lacking unobviousness over Fukuta (U.S. Patent No. 4,745,011) in view of Morris (U.S. Patent No. 3,989,228).  The second was an obviousness argument based on Jacobsen (U.S. Patent No. 6,241,125) in view of other references.  These two proposed amendments were adopted by the examiner, but after briefing were withdrawn before a Right of Appeal Notice (RAN) was issued confirming the claims of the ’384 patent.  Plas-Pak appealed to the Patent Trial and Appeal Board (PTAB), which affirmed the examiner’s decision not to adopt Plas-Pak’s proposed rejections.

The proposed rejections based on Fukuta were based on disclosure of a two-component coating apparatus, which is schematically shown below. The main component and the hardener are separately piped to the spray gun (1) via an independent series of pumps (2), check valves (4), stop valves (5), and an escape valve (6).  Fukuta explained that this arrangement of pumps and valves was intended to prevent backflow at high velocities.

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The combination proposed by Plas-Pak would replace the pumps and valves with cartridges taught by Morris. Morris is directed to a device with a static mixing chamber for mixing components of a composition before dispensing.

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The PTAB found, and the Federal Circuit affirmed on substantial evidence, that the combination of Fukuta and Morris would not have been obvious because the pumps and valves of Fukuta are essential to its “principle of operation,” i.e., preventing backflow at high velocities.  The Morris cartridges would not be a simple combination of elements, as argued by Plas-Pak, because removing the pumps and valves of Fukuta would remove the very systems disclosed by Fukuta disclosed as achieving its stated goal.  The Federal Circuit also noted that the specification is “rife with statements defining ‘the invention’ as adding stop valves to prevent backflow.”  Plas-Pak, No. 2014-1447, slip op. at 6.  Bearing in mind that the “principle of operation” is a question of fact, and because substantial evidence supported the PTAB’s decision, the court affirmed while noting that “a change in a reference’s ‘principle of operation’ is unlikely to motivate a person of ordinary skill to pursue a combination with that reference.”  Id. at 7 (citations omitted).

Turning next to Jacobsen, the PTAB had affirmed the examiner’s decision not to adopt Plas-Pak’s proposed rejections based on Jacobsen on the theory that the proposed rejection would violate Jacobsen’s “intended purpose.” The Jacobsen reference is directed to a device for filling structural cracks, not spraying paint.  Plas-Pak argued that the “intended purpose” is broadly conveying multiple components before being discharged where and when needed.  The PTAB, affirmed by the Federal Circuit on substantial evidence, disagreed, however, finding that the “intended purpose” of Jacobsen was filling cracks, not spraying paints. The court agreed with the PTAB that one of skill in the art would have no reason to add a spray nozzle to the Jacobsen device.

The Plas-Pak case illustrates how two inquiries can affect the determination of whether a combination is obvious or not. First, when a reference’s “principle of operation” can be defined rather narrowly, then it will naturally be harder to modify the disclosed embodiments to replace components related to that “principle of operation” with a teaching reference’s components, unless that combination preserves the “principle of operation.”  In Plas-Pak, the wholesale substitution of elements required to invalidate the claims also destroyed Fukuta’s “principle of operation,” which mitigated against a finding of obviousness. Second, when a reference’s “intended purpose” is violated by a proposed modification and a disclosed invention is rendered inoperative for its intended purpose, then a person of ordinary skill would not have been motivated to pursue the combination.

The insights of Plas-Pak—and the line of cases cited in the opinion—might be useful in attacking rejections where obviousness is based on grounds that violate a prior art reference’s “principle of operation” or “intended purpose.”  Because these attributes are questions of fact, applicants should build a record that will support an advantageous position, which could include using declarations in appropriate circumstances.