Arguments Unrelated To Patentablilty Preclude Infringement
Even though an examiner’s reasons for allowance do not depend on purported distinctions from prior art, a Federal Circuit panel concludes that arguments directed to such distinctions can preclude literal infringement in Harvey D. Gillespie v. Dywidag Systems International, USA (No. 2006-1382, September 6, 2007).
Dywidag appeals a district court decision entering final judgment that certain claims of Gillespie’s patents are literally infringed by Dywidag’s mine roof bolt, which is rotated by way of a key socket recessed in an end of the bolt head. It was conceded that the accused Dywidag device met all claim limitations literally, except for a “…drive collar…having an outer surface defining a drive head that accepts a driving mechanism….” During prosecution, Gillespie had argued that the collar at the end of a prior art bolt was cylindrical on its outside and impractical for engagement by a bolting machine. Gillespie now stresses that his claims should not be limited in a way that excludes the prior art structure because the examiner’s reasons for allowance did not depend on how the drive collar is rotated.
The Federal Circuit panel modifies the district court claim construction, concludes that, on the modified construction, literal infringement cannot be found, and reverses. Noting that the mechanism by which the Gillespie bolt is grasped by a tool and rotated is not the only difference from the prior art, the panel still determines that a person of ordinary mechanical skill would not read the specification, the drawings, and the claims of the Gillespie patent to construe “outer surface” of the drive collar to include a collar whose interior, not exterior, accepts a drive tool. Although Gillespie argues that this distinction was not material to the grant of his patent, he nonetheless argued this distinction from the prior art during prosecution. A cylindrical outer surface that is not adapted to be grasped by a drive tool characterizes both the prior art and the Dywidag bolt heads, and such a construction of Gillespie’s patent claims was negated during prosecution.
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