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Sock Patent Found Invalid

March 12, 2001

Decision icon Decision

Last Month at the Federal Circuit - April 2001

Judges: Gajarsa (author), Schall, and Friedman

In Herman v. William Brooks Shoe Co., No. 00- 1228 (Fed. Cir. Mar. 12, 2001) (nonprecedential decision), the Federal Circuit affirmed a district court’s grant of SJ of patent invalidity for anticipation.

Jack Herman had charged L.L. Bean, Inc. and several other Defendants (collectively “L.L. Bean”) with infringement of U.S. Patent No. 4,550,446 (“the ‘446 patent”). The ‘446 patent is directed to footwear designed to keep a user’s feet dry from the outside while allowing evaporation of moisture from the feet through the insert material. Claim 1 is directed to a sock formed of a material being substantially waterproof from the outside and moisture vapor permeable from the inside.

L.L. Bean moved for SJ of invalidity of claim 1 in view of U.S. Patent No. 4,204,345 (“the ‘345 patent”). The ‘345 patent is directed to a “liquid impermeable sock member” that is air permeable. The ‘345 patent describes the sock material as being preferably air permeable and lists several suitable plastics.

At a Markman hearing, Herman conceded that all elements of claim 1 of the ‘446 patent, except for the moisture-vapor-permeable element, were disclosed in the ‘345 patent. After reviewing the ‘345 patent, the district court found that an airpermeable material allowed transmission of air and water vapor. As a result, the district court held that all elements of claim 1 of the ‘446 patent were disclosed by the ‘345 patent; therefore, claim 1 was anticipated and invalid.

On appeal, Herman argued that the terms “air permeable” and “moisture vapor permeable” are not the same. In addition, Herman argued that the ‘446 patent disclosed Gore-Tex, which has a higher transmission rate of water vapor than the materials listed in the ‘345 patent, as being one of the insert materials. The Court found neither argument persuasive. Herman’s own expert admitted that the materials listed in the ‘345 patent would allow transmission of water vapor through the material. In addition, the Court was unwilling to read the water transmission rate of the Gore-Tex material into the claim. As a result, it affirmed the district court’s grant of SJ.