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Control for a door closer having a power-assist opening feature

  • US 5,251,400 A
  • Filed: 06/29/1992
  • Issued: 10/12/1993
  • Est. Priority Date: 06/29/1992
  • Status: Expired due to Term
First Claim
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1. A control for an hydraulically driven door closer/opener including an hydraulic circuit having an electric pump, an electric circuit for activating the pump, an hydraulic cylinder in the hydraulic circuit operatively enclosing a piston provided with a rack, the rack driving a pinion having a shaft extending outside the cylinder connected to the operating arm of the door, the pump adapted to pressurize the hydraulic circuit to drive the piston toward the open position of the door, the control comprising:

  • 1) drive wheel frictionally mounted on the pinion shaft external of the cylinder,2) pump-activating means comprising;

    a. an activating arm extending outward from the wheel and frictionally gripped by the wheel,b. a fixed pump-on photoelectric sensor in the electric circuit mounted adjacent the end of the arm and adapted to turn on the pump when the arm arrives at a position closely proximate the sensor,c. an adjustable abutment surface to limit the movement of the arm away from the sensor,3) pump-deactivating means comprising;

    a. a driven rotary follower mounted on the closer/opener adjacent the wheel and having an axis parallel to the pinion shaft,b. a deactivating arm extending outward from the follower,c. a fixed pump-off photoelectric sensor in the electric circuit mounted adjacent the end of the deactivating arm and adapted to turn off the pump when the deactivating arm leaves a position closely proximate the pump-off sensor,d. interfitting lost-motion-transmitting means on the peripheries of the wheel and the follower, such that when the wheel nears a position corresponding to the desired openness of the door, the lost-motion-transmitting means causes the follower to rotate to swing the deactivating arm away from the sensor to turn off the pump.

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