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Tamperproof hydrant lock with controlled shock absorber

  • US 4,139,016 A
  • Filed: 08/31/1977
  • Issued: 02/13/1979
  • Est. Priority Date: 04/19/1977
  • Status: Expired due to Term
First Claim
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1. In a fire hydrant including a bonnet having an aperture, a housing having an internal chamber, an operating rod extending within the housing chamber, a yoke coupled to the operating rod, and a plunger coupled to the yoke for opening and closing a valve, a tamperproof lock comprising:

  • a spring mounted on the housing;

    power transmitting means mounted on the operating rod for transmitting power to said rod against said spring;

    first hydraulic means operatively associated with said power transmitting means for controlling gradual opening of the valve over a first delay interval of time; and

    second hydraulic means operatively associated with said power transmitting means for controlling gradual closing of the valve over a second delay interval of time.

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