Patents by Inventor Gilbert Stokes

Gilbert Stokes has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Tennis ball throwing machine
    Patent number: 3990426
    Abstract: Tennis balls are introduced via a removable ball pick-up magazine through a ball port in a wall of a pipe into a stream of air flowing through the pipe towards a barrel. Air flows freely through the barrel and through the ball port past a normally open flexible flap valve which permits a ball to pass, but which momentarily seals against the curved wall of the pipe in response to back pressure after a ball passes through the port and chokes the free flow of air through the barrel.
    Type: Grant
    Filed: July 22, 1975
    Date of Patent: November 9, 1976
    Inventor: Gilbert Stokes