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Vehicle power antenna control with drive stress limiting

  • US 4,730,152 A
  • Filed: 11/17/1986
  • Issued: 03/08/1988
  • Est. Priority Date: 11/17/1986
  • Status: Expired due to Fees
First Claim
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1. A power antenna control for a motor vehicle having antenna drive means effective to extend and retract the antenna relative to the vehicle, the antenna drive means including a DC motor having an armature, the control comprising, in combination:

  • pulse signal means responsive to movement of the antenna drive means to generate pulses for equal predetermined increments of antenna travel;

    a first counter responsive to the pulse signal means while the antenna is extending to change its count in a first direction and while the antenna is retracting to change its count in the opposite direction to thereby maintain a count indicative of antenna position;

    a second counter responsive to the pulse signal to count in a first direction;

    means responsive to the first counter during antenna extension to deactivate the antenna drive means when the count of the first counter indicates a predetermined extended antenna position;

    means effective to periodically monitor the count of the second counter and reset the count to an initial value and, when said monitored count is less than a predetermined count indicating motor stall, to generate a stall signal;

    means responsive to the stall signal during antenna retraction to deactivate the antenna drive means and, if the count of the first counter is within a predetermined count of full retraction, to reset the count of the first counter to the count indicating full retraction;

    means activatable to limit the current in the motor armature to a predetermined maximum value; and

    means responsive to the first counter to activate the current limiting means only when the count of the first counter is within a range corresponding to a predetermined range of antenna position close to full retraction.

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