Wilson Sporting Goods Co. v. David Geoffrey & Associates
904 F.2d 677 (1990)
Wilson invented and got a
patent on a golf ball will a specific pattern of dimples to make it go
farther. They sued Dunlop for infringement for making a similar golf ball.
Dunlop argued that Wilson's
patent said that none of the dimples could intersect lines of certain
geometric patterns on the ball. Since Dunlop's ball's dimples did
intersect those lines, it wasn't infringing.
Wilson argued that Dunlop's
golf ball only barely intersected the lines, therefore it was still
infringing via the Doctrine of Equivalence.
The Doctrine of
Equivalents says that a product or
process that does not literally infringe upon the express terms of a
patent claim may nonetheless be found to infringe if there is an equivalence between the elements of the accused product
or process and the claimed elements of the patented invention.
Dunlop argued that Wilson
limited their claim because there was already a golf ball in the prior
art made by Uniroyal that intersected
the lines to about the same level as Dunlop's golf ball did.
The Trial Court found for
Wilson. Dunlop appealed.
The Appellate Court reversed.
The Appellate Court found
that there can be no infringement if the asserted scope of equivalency of
what is literally claimed would encompass the prior art.
The Court found that if
Wilson had tried to claim exactly what Dunlop made, the claim would have
been rejected because of Uniroyal's prior art. Therefore Wilson could not claim it via the Doctrine
The Court suggested that
the test courts should use was to draft a hypothetical claim that
encompasses the accused infringer's product. If that hypothetical claim
would hypothetically be valid, then the Doctrine of Equivalents could be used.
Basically, in this case, the
court said that the Doctrine of Equivalents could not be used to claim something you couldn't have legally
claimed in the original patent.