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 of Equivalents.
      • 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.