Patent Counsel: Do Your Patents Claim Engagement of Components as Intended?

A recent Federal Circuit decision provides a reminder that even in the mechanical arts, where terms have generally understood and accepted meanings, it remains important to avoid use of claim terms that may lead to ambiguity, and to otherwise include a description of the subject matter intended to be encompassed by such terms.

Background of CoolIT Sys., Inc. v. Vidal, No. 2022-1221 (Fed. Cir. Mar. 7, 2024) (nonprecedential)

CoolIT Systems, Inc. (“CoolIT”) appealed a final written decision of the United States Patent and Trademark Office (“PTO”) Patent Trial and Appeal Board (“the Board”) holding claims 1–3, 5, 7, and 25 of U.S. Patent 9,057,567 (“the ’567 patent”) unpatentable over prior art. 

The ’567 patent is directed to a system for fluid heat transfer to cool electronic devices.  The main issue on appeal was the correct construction of the claim term “matingly engaged” (e.g., claim 1 of the ’567 patent requires “a compliant member matingly engaged with the second side of the housing member”).  CoolIT argued “matingly engaged” should be construed as “mechanically joined or fitted together to interlock” (or, alternatively, “mesh” or “otherwise engage”).  The Board did not agree, and contended that: 1) CoolIT’s proposed construction improperly read a limitation from the specification into the claim, which restricted “matingly engaged” to only the interlocking of complementary contoured features, to the exclusion of other forms of engagement; and, 2) neither the claims nor the specification use the word “interlock.”  However, the Board did not itself propose a complete construction of “matingly engaged.”  Instead, the Board’s partial construction found “matingly engaged” includes when “at least a portion of the recited compliant member is fitted within the recessed region defined by the second side of the housing member.”

Federal Circuit Holdings

The Federal Circuit rejected both constructions and instead provided a separate construction of “matingly engaged,” then remanded the case for reconsideration of prior art grounds in view of its new construction. 

• The Federal Circuit agreed “mating engagement” does not encompass all types of engagement, contact between two flat surfaces, or the joining together of two flat surfaces, nor does it merely require contact or attachment.
• The Federal Circuit rejected the Board’s partial construction because it largely rendered superfluous other portions of the claim. For example, claim 1 also requires “wherein a portion of the compliant member occupies a portion of the recessed region defined by the second side of the housing member and urges against a corresponding wall of the recessed region while leaving a portion of the recessed region defined by the second side of the housing member unoccupied.”  The Federal Circuit found the Board failed to explain how “fitted within the recessed region” in its partial construction is different from “occupies a portion of the recessed region” and “urges against [a portion of it].”  Thus, the Federal Circuit believed “matingly engaged” must carry greater meaning than “fitted within.”
• The Federal Circuit rejected the Board’s partial construction also because it did not use the phrase “join or fit together,” where the Board agreed mating engagement requires “joining or fitting together” in some fashion. The Federal Circuit believed the construction should include “joined or fitted together,” because “fitted within” and “fitted to” do not necessarily have the same meaning as “fitted together.”
• As to how to construe the term “engaged,” the Federal Circuit disagreed “interlock” should be the answer, as “interlock” might cause more confusion than clarity. For example, CoolIT asserted complementary contoured shapes are not required for interlocking, while the PTO asserted they are required.  
• The Federal Circuit concluded the correct construction of “matingly engaged” should be “mechanically joined or fitted together,” as it encompasses components that are joined by overlapping, as well as components that are interlocking or with complementary shapes, but is not limited to such. Also, inclusion of “mechanically” excluded connection via chemical bonds, e.g., sealing and welding.  CoolIT stressed “matingly engaged” is not the same thing as either (a) sealing, such as through glue, solder, or another intermediary filler which separates the components, or (b) welding, which joins two components to make them one.  The Federal Circuit agreed, and also found support for its construction based on the ’567 patent also distinguishing between mating engagement and sealing.

Takeaways

• In claim drafting, to describe the interface/connection of two components, some terms are often used, such as “mate” and “engaged,” but an applicant may want to provide a clear definition of these terms in the specification to avoid unexpected claim constructions in the future, even when it is believed the terms have generally understood and accepted meanings.
• Terms should be used consistently throughout the entire application; any minor changes may be construed to mean different things, such as, for example, “fitted together,” “fitted within,” or “fitted to.”
• During litigation, when advancing a construction of a claim term, parties should be careful to avoid proposing a definition that itself requires further constructions (e.g., “interlock”), as judges seek to adopt constructions that provide clarity, and avoid creating new disputes.
• Litigants may seek to attack a proposed construction on the basis that such proposal simply “moves the goal post,” without defining the metes and bounds of a given term.