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Door closer having means to neutralize the door closing force exerted thereby

  • US 4,010,572 A
  • Filed: 06/02/1975
  • Issued: 03/08/1977
  • Est. Priority Date: 06/02/1975
  • Status: Expired due to Term
First Claim
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1. In combination with a door which moves between open and closed positions with respect to a door opening in a wall, the improvement comprising:

  • force means for providing a restoring force when the door is opened;

    transfer means between the force means and the door for causing the restoring force to urge the door to its closed position;

    neutralizing means for at least in part neutralizing the force exerted by the force means when the door is opened by an individual desiring to pass through the door opening, the neutralizing means being an air cylinder including a barrel and a piston rod which moves relative to the barrel when the barrel is pressurized and which exerts a neutralizing force on the transfer means in opposition to the force exerted by the force means; and

    a valve carried by the door and connected between the air cylinder and a source of pressurized air for admitting the air to the air cylinder when activated.

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