925 F.2d 1444 (Fed. Cir. 1991), 90-1342, Key Mfg. Group, Inc. v. Microdot, Inc.

Docket Nº:90-1342.
Citation:925 F.2d 1444
Party Name:17 U.S.P.Q.2d 1806 KEY MANUFACTURING GROUP, INC., Plaintiff-Appellee, v. MICRODOT, INC., Defendant-Appellant.
Case Date:February 13, 1991
Court:United States Courts of Appeals, Court of Appeals for the Federal Circuit
 
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Page 1444

925 F.2d 1444 (Fed. Cir. 1991)

17 U.S.P.Q.2d 1806

KEY MANUFACTURING GROUP, INC., Plaintiff-Appellee,

v.

MICRODOT, INC., Defendant-Appellant.

No. 90-1342.

United States Court of Appeals, Federal Circuit

February 13, 1991

Rehearing Denied March 15, 1991.

Jerold I. Schneider, Spencer & Frank, Washington, D.C., argued, for plaintiff-appellee. With him on the brief was Catherine M. Voorhees.

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Kenneth J. Jurek, Mayer, Brown & Platt, Chicago, Ill., argued, for defendant-appellant. With him on the brief was Rosanne J. Faraci.

Before PLAGER and RADER, Circuit Judges, and FRIEDMAN, Senior Circuit Judge.

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RADER, Circuit Judge.

The United States District Court for the Eastern District of Michigan adjudged Microdot, Inc. (Microdot) liable for infringement of reexamined United States Patent No. B1-4,123,961 ('961 patent) owned by Key Manufacturing Group, Inc. (Key). The district court held that Microdot's capped wheel nuts infringe the '961 patent claims literally and under the doctrine of equivalents. Key Mfg. Group, Inc. v. Microdot, Inc., 15 USPQ2d 1195 (E.D.Mich.1990). This court reverses.

BACKGROUND

Both Key and Microdot manufacture capped wheel nuts used to attach a wheel to a car axle. The wheel nuts have several sides or "wrench flats" to permit a tool to grasp the nut for tightening or loosening. The nut body has two faces. The nut face in direct contact with the wheel is the "wheel face." The opposite or exterior face is the "cap face."

The '961 patent discloses and claims a decorative nut and stainless steel cap for attachment to the nut body. The stainless steel cap has sides corresponding to the wrench flats. Welds secure the decorative cap to the cap face of the nut body. Claim 1 of the '961 patent reads as follows:

1. A decorative nut for holding a wheel on a motor vehicle and exposed to view on the wheel, said nut having a central threaded aperture, polygonal sides, a first end adapted to engage a wheel, a second end opposite said first end and having an end face extending at right angles to the axis of the nut, and a sheet metal cap for the nut and having a section extending over the polygonal sides of the nut and an end section adapted to cover the second end of the nut, said section extending over the polygonal nut sides including a plurality of cap wrench flats respectively associated with and oppositely facing said polygonal nut sides, said cap wrench flats and said polygonal nut sides being disposed between said first and second ends of said nut, said end section being connected to the section of the cap which covers the polygonal nut sides by a section formed fully around the perimeter of the cap and having an extension at right angles to the axis of the nut so as to be parallel to said end face, such connecting section being in juxtaposed contact throughout a substantial area with and welded to said end face, the position of welded contact between the connecting section and the end face resulting in shear forces being applied to the weld in response to the application of forces on the capped wrench flats which create moments about the central axis of the nut.

(Emphasis added.) The highlighted portion constitutes the disputed "at right angles" and "substantial area" claim language. The invention is illustrated in the '961 patent in part as follows:

NOTE: OPINION CONTAINS TABLE OR OTHER DATA THAT IS NOT VIEWABLE

NOTE: OPINION CONTAINS TABLE OR OTHER DATA THAT IS NOT VIEWABLE

NOTE: OPINION CONTAINS TABLE OR OTHER DATA THAT IS NOT VIEWABLE

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