Judges: Rader (author), Schall, Prost

[Appealed from E.D. Mich., Judge Rosen]

In Welker Bearing Co. v. PHD, Inc., No. 08-1169 (Fed. Cir. Dec. 15, 2008), the Federal Circuit affirmed the district court’s grant of SJ of noninfringement of Welker Bearing Company’s (“Welker Bearing”) U.S. Patent Nos. 6,786,478 (“the ’478 patent”) and 6,913,254 (“the ’254 patent”) in favor of PHD, Incorporated (“PHD”).

The ’478 and ’254 patents, which share identical specifications, claim pin clamps that hold a workpiece securely in place during welding and other manufacturing processes. The disclosed pin clamps feature a bullet-shaped locating pin that is inserted into a hole in a workpiece. An actuator propels the locating pin through the hole in the workpiece. As the locating pin slides through the workpiece’s hold, clamping fingers emerge out of the pin clamp. These fingers hold the workpiece firmly in place against an annular ring that sits below the locating pin. The actuator provides a clamping force between the fingers and the workpiece.

After the PTO allowed the claims of the ’478 patent, Welker Bearing filed a continuation application with broader claims. The continuation application issued as the ’254 patent. Claim 1 of the ’478 patent explicitly requires a rotational movement mechanism for extending and retracting the fingers, while claim 1 of the ’254 patent does not.

Before the district court, Welker Bearing accused two PHD products, the “Clamp I” and “Clamp II” devices, of infringement. Clamp I, which was developed before Clamp II, used a rotational mechanism to move clamping fingers into and out of the pin clamp. After the ’478 patent issued, Welker Bearing learned that PHD had developed the Clamp I device. Welker Bearing notified PHD in writing that it believed Clamp I infringed the ’478 patent. Since Welker Bearing refused to give PHD a license, PHD developed a modified design, Clamp II, which lacked a rotating central post for moving clamping fingers in and out of the locating pin.

Welker Bearing filed suit against PHD asserting infringement of both the ’478 and ’254 patents. Welker Bearing conceded that Clamp II did not infringe the ’478 patent because it lacked a rotational mechanism for clamping fingers. Thus, the district court limited the issues to Clamp I’s possible infringement of the ’478 patent and Clamp II’s possible infringement of the ’254 patent. The district court awarded SJ of noninfringement to PHD on the ’478 and ’254 patents. Welker Bearing appealed these rulings.

The Federal Circuit found that the record did not contain any evidence that PHD engaged in any activity that infringed the ’478 patent after the day the ’478 patent issued. Instead, the record showed that PHD only created around ten prototype units of the Clamp I device that never entered production or commercial use. Since the burden remains with the patentee to prove infringement, and Welker Bearing failed to prove any sales of the Clamp I after the ’478 patent issued, the Court found that the district court did not err in granting SJ of noninfringement of the ’478 patent.

The Court then considered whether the “mechanism for moving said finger” limitation in claim 1 of the ’254 patent invoked 35 U.S.C. § 112, ¶ 6. The ’254 patent’s claim language does not include the word “means,” but instead the similar word “mechanism.” The Court considered past cases in which it examined the applicability of means-plus-function treatment in the context of the claim term “mechanism.” In Massachusetts Institute of Technology v. Abacus Software, 462 F.3d 1344, 1354 (Fed. Cir. 2006) (“MIT”), the Court examined the applicability of means-plus-function treatment to the term “colorant selection mechanism.” In MIT, the Court stated that the term “mechanism” standing alone connotes no more structure than the term “means.” However, the claim language that further defines a generic term like “mechanism” can sometimes add sufficient structure to avoid § 112, ¶ 6. The Court read “colorant selection mechanism” as invoking treatment as a functional claim because it did not add sufficient structure.

By contrast, in Greenberg v. Ethicon Endo-Surgery, Inc., 91 F.3d 1580 (Fed. Cir. 1996), the Court held that § 112, ¶ 6 did not apply to the term “detent mechanism,” because the noun “detent” denotes a type of device with a generally understood meaning in the mechanical arts. The Court examined several definitions of “detent.” Because these definitions connoted adequate structure that was reasonably well understood in the art, the Court concluded that “detent mechanism” was not a mere functional placeholder.

The Court analyzed “mechanism for moving said finger” in light of this case law. The Court found that the “mechanism for moving said finger” language includes even less structural context than the “colorant selection mechanism” in MIT. No adjective endows the claimed “mechanism” with a physical or structural component. Further, claim 1 provides no structural context for determining the characteristics of the “mechanism” other than to describe its function. Thus, the unadorned term “mechanism” is “simply a nonce word or a verbal construct that is not recognized as the name of structure and is simply a substitute for the term ‘means for.’” Slip op. at 9 (citation omitted). The Court therefore held that the district court properly applied means-plus-function treatment to this term.

The Court found that the ’254 patent’s specification fully supported the district court’s construction of “mechanism for moving” as including a rotating central post. The specification repeatedly identified a rotating central post as the disclosed structure for performing the claimed function of “moving said finger.” And the Court noted that “[n]othing in the specification suggests any other structure for moving the claimed fingers.” Id. at 12.

The Federal Circuit then held that the Clamp I product could not infringe the ’254 patent because the ’254 patent issued after the ’478 patent. The Court therefore focused on whether PHD’s Clamp II device infringed claim 1 of the ’254 patent. The record showed that Clamp II propels clamping fingers in and out of the locating pin without any rotational movement. Instead, Clamp II’s linear-moving mechanism for finger movement and the claimed “mechanism for moving said finger” with a rotating central post are “substantially different.” Thus, the Clamp II device did not literally infringe.

The Court then rejected Welker Bearing’s DOE argument, stating that this was not a case under the DOE at all, but presented only the question of structural equivalents under § 112, ¶ 6. Structural equivalents and the DOE are related in the sense that they both apply similar analyses of insubstantiality of the differences between a disclosed structure and an accused infringing structure. The difference between the two inquiries is that an equivalent structure under § 112, ¶ 6 must have been available at the time of the issuance of the claim, whereas the DOE can capture after-arising technology developed after the issuance of the patent.

The Court found that the record demonstrated that PHD’s linear-moving mechanism for finger movement was well known in the prior art and cannot be classified as after-arising technology. Thus, the Court held that where, as here, a proposed equivalent has arisen before patent issuance, a § 112, ¶ 6 structural equivalents analysis applies and any analysis for equivalent structure under the DOE collapses into the § 112, ¶ 6 analysis. The Court determined that under any analysis, Welker Bearing could not show equivalence between its disclosed mechanism and the Clamp II mechanism. Thus, the Court affirmed the district court’s grant of SJ of noninfringement of the ’254 patent.