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Safety apparatus for elevator system

  • US 4,256,204 A
  • Filed: 08/31/1978
  • Issued: 03/17/1981
  • Est. Priority Date: 09/02/1977
  • Status: Expired due to Term
First Claim
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1. A safety apparatus for an elevator system, comprising:

  • a power supply;

    a motor supplied with power by said power supply;

    a sheave driven by said motor;

    an elevator car operated by the rotation of said sheave;

    an electromagnetic brake capable of holding the elevator motion system of said motor, said sheave and said car in a stop condition;

    an elevator control device to which power is supplied from said power supply;

    voltage drop responsive means being operated in response to the voltage drop of said power supply to a predetermined voltage which is higher than the deenergization voltage of any of the relays included in said elevator control device and lower than the normal voltage of said power supply, said voltage drop responsive means being restored to a nonoperation state in response to the recovery of said power supply to the normal voltage thereof;

    emergency brake means for applying an emergency brake to said elevator motion system; and

    holding means responsive to the operation of said voltage drop responsive means for maintaining said emergency brake means in an operated condition until said elevator motion system comes to a stop.

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