Patents Assigned to Helmut Hund K.G.
  • Patent number: 4686598
    Abstract: A safety circuit for a window lift driven by an electric motor is described which causes a reversal in the direction of rotation of the drive motor when the window pane impinges on an impedance in its upward motion. The reversal criterion used is the motor current surge familiar to the state of the art. The circuit of the invention is characterized in that upon actuation of the "close" window key, the drive motor first rotates briefly in the direction of opening and thereby displaces the window pane downwardly, whereupon it is automatically reversed and only then does the pane motion toward the closed position begin. Consequently, the motor start-up peak current decays in that range of displacement of the window pane which is below its initial position, whereby an increase in current (di/dt) after resuming the initial position of the window pane at once causes motor reversal.
    Type: Grant
    Filed: December 3, 1984
    Date of Patent: August 11, 1987
    Assignee: Helmut Hund K.G.
    Inventor: Klaus-Dieter Herr