April 24, 2014

Has the Doctrine of Claim Vitiation Itself Been Vitiated? Re: Patent Litigation

Addressing the doctrine of claim differentiation in the context of summary judgment, the U.S. Court of Appeals for the Federal Circuit reversed summary judgment of non-infringement, concluding that the doctrine of claim vitiation was not a bar against plaintiff’s application of the doctrine of equivalence even when elements are read out of the claims.  The Charles Machine Works, Inc. v. Vermeer Manufacturing Co., Case No. 12-1578 (Fed Cir., July 26, 2013) (Moore, J.).

Charles Machine Works (CMW) asserted a patent relating to boring underground holes in the horizontal direction using a two-pipe drill made up of an inner pipe for rotating a drill bit and an outer pipe for steering the drill against Vermeer Manufacturing (Vermeer).  The patent claims a structure, the “deflection shoe,” which operates as a steering mechanism by deflecting the drill away from a straight drilling path.  A question posed at the district court level was whether the claimed “deflection shoe,” which was expressly claimed as “mounted on a first side of the body,” must be mounted on an outer pipe.

In its motion for summary judgment of no infringement, Vermeer argued, inter alia, that a finding of equivalence between the claimed “mounted deflection shoe” and the accused component, which was not mounted, would read the “deflection shoe” and “mounted on” limitations out of the claims. Thus, such a finding is barred by the doctrine of claim vitiation. The district court discounted CMW’s expert declaration and granted Vermeer’s motion for summary judgment of no infringement based on the apparent express claim requirement that the “deflection shoe,” or equivalent thereof, must be “mounted on” the drilling apparatus.  CMW appealed. 

The Federal Circuit concluded that summary judgment was not appropriate as CMW’s expert declaration, which supported equivalency between the accused component and the claimed “deflection shoe,” had established a genuine dispute with regard to equivalence.  The Court explained that the expert testimony established a case for equivalence between the claimed and accused structures using the “function-way-result” test, notwithstanding that the expert’s broad application of the equivalency test essentially read the “mounted on” limitation out of the claim.  The Federal Circuit panel explained that the appropriate question for the district court, on summary judgment, was whether a reasonable jury could find equivalence based on the record.

Practice Note:  The panel ruling in this case may be compared with other Federal Circuit decisions regarding the conventional understanding that equivalence should be determined on an  element-by-element analysis, e.g.Asyst Technologies v. Emtrak, (“This case falls within both that doctrine and its corollary, the “specific exclusion” principle, since the term “mounted” can fairly be said to specifically exclude objects that are “unmounted.”); Brilliant Instruments v. GuideTech, (“[Equivalence] will be more difficult when the accused structure has an element that is the opposite of the claimed element.”).

© 2014 McDermott Will & Emery

About the Author


Stephen M. Yu is an associate in the law firm of McDermott Will & Emery LLP and is based in the Firm’s New York office.  Stephen focuses his practice on intellectual property litigation and patent prosecution.


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