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Door operator safety feature requiring constant actuation to close door

  • US 4,872,082 A
  • Filed: 04/05/1988
  • Issued: 10/03/1989
  • Est. Priority Date: 09/02/1987
  • Status: Expired due to Fees
First Claim
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1. A door operator safety circuit comprising:

  • a motor operable to move a door between an open position and a closed position;

    a momentary contact push button switch generating an operator command when activated;

    a motor controller connected to said motor and said momentary contact push button switch controlling said motor upon each receipt of said operator command from said momentary contact push button switch to advance to the next state in the circular sequence of states including (1) move the door in the closing direction, (2) stop, (3) move door in the opening direction, and (4) stop, said motor controller further having a safety mode controlling the motor to move the door to a safe position when triggered;

    a safety switch coupled to the door and connected to said motor controller triggering said safety mode of said motor controller upon detection of an unsafe condition of the door; and

    a safety circuit connected to said momentary contact push button switch and said motor controller triggering said safety mode unless said momentary contact push button switch continuously generates said operator command during movement of the door.

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