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Control circuit for a motor-driven door operator

  • US 4,263,536 A
  • Filed: 08/07/1978
  • Issued: 04/21/1981
  • Est. Priority Date: 08/07/1978
  • Status: Expired due to Term
First Claim
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1. An improved control circuit for a motor-driven door operator comprising:

  • an up limit switch activated when the door is in an open position,motor sequence initialization circuitry connected to the up limit switch and to an external power supply and responsive to connection of power after the door operator is installed and responsive to restoration of power after a power outage for setting the sequence of operation of a selectively energizable reversible motor so the motor is initially energized for actuating a drive mechanism to move the door toward a closed position when the control circuit is activated if the up limit switch is activated and so the motor is initially energized for actuating the drive mechanism to move the door toward the open position when the control circuit is activated if the up limit switch is not activated,a selectively activated control switch for activating the control circuit to energize the motor for actuating the drive mechanism to move the door between the open and closed positions,time delay circuitry connected to the control switch and responsive to activation of the control switch for timing a predetermined time delay period,a safety switch activated by yieldable means actuable when the force on the drive mechanism exceeds a force represented by the door and the drive mechanism in motion,a down limit switch activated as the door closes near the closed position,obstruction detection circuitry connected to the safety switch, the down limit switch and the time delay circuitry and responsive to expiration of the time delay period for energizing the motor so that, if the safety switch is activated while the door moves toward the closed position after the time delay period expires and the down limit switch is not activated, the motor actuates the drive mechanism to move the door toward the open position and for de-energizing the motor if the safety switch is activated while the door moves toward the open position after the time delay period expires,timer circuitry connected to the down limit switch and to the safety switch and responsive to activation of the down limit switch for energizing the motor no more than a predetermined additional time for actuating the drive mechanism to move the door toward the closed position and responsive to activation of the safety switch for de-energizing the motor,the up limit switch being activated as the door opens near the open position for de-energizing the motor, andmaximum run-time circuitry connected to the up and down limit switches, the safety switch and the control switch for de-energizing the motor in the event that one of the up and down limit switches and/or safety switch fails and energization of the motor continues after a maximum predetermined time elapses following activation of the control circuit and for setting the sequence of operation of the motor so the motor is energized for actuating the drive mechanism to move the door toward the open position when the control circuit is activated.

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