Patents Assigned to John J. Schlager
  • Electric indicator system for ball games
    Patent number: 4092634
    Abstract: An improved electric circuit and indicator system for a court game, such as tennis, using conductive elements on both the ball and outside the court playing area to activate an indicator when the ball drops outside the playing area; wherein said system includes means for deactivating said indicator when the ball contacts one of the playing lines to avoid erroneous indication caused by a skidding ball.
    Type: Grant
    Filed: October 6, 1976
    Date of Patent: May 30, 1978
    Assignee: John J. Schlager
    Inventor: Henry Von Kohorn