Tamperproof lock with shock absorber

In a fire hydrant including a housing having an internal chamber and an internally threaded portion, a threaded operating rod extending within the housing chamber coupled to a yoke, and a plunger coupled to the yoke for opening and closing a valve, the combination comprising:

• a modified retaining ring threadedly mounted on an internally threaded portion of a housing;
• an operating nut converter threadedly mounted on a threaded operating rod extending within a housing chamber;
• a pressure plate threadedly mounted on said operating nut converter, said pressure plate having an annular recess formed in its underside and a circular recess formed in its topside;
• a swivel plate freely mounted in said pressure plate circular recess for rotational movement therein, said swivel plate having a conically shaped central hub portion;
• a piston ring threadedly mounted on said operating nut converter;
• said housing chamber containing hydraulic fluid for contact with said piston ring;
• and
• a spring mounted at one end on the housing and adapted to fit at the other end within said pressure plate annular recess whereby said spring exerts an upward force against the underside of said pressure plate.

In a fire hydrant including a bonnet having an aperture, a housing having an internal chamber, a threaded operating rod extending within the housing chamber coupled to a yoke, and a plunger coupled to the yoke for opening and closing a valve, a tamperproof lock comprising:

• a spring mounted at one end on a housing;
• power transmitting means threadedly mounted on a threaded operating rod extending within a housing chamber for transmitting power to said threaded rod against said spring;
• hydraulic means operatively associated with said power transmitting means for preventing sudden closing of the hydrant valve;
• a swivel plate freely mounted on said power transmitting means for rotational movement thereon, said swivel plate having a contoured hub portion adapted to fit within a bonnet aperture, said hub portion being exposed to the exterior of the bonnet;
• and
• power applying means removably mounted on the bonnet for applying power substantially along the axis of the operating rod to move the rod against said spring and said hydraulic means by contacting the contoured hub portion of said swivel plate.

In a fire hydrant including a housing having an internal chamber and an internally threaded portion, a threaded operating rod extending within the housing chamber coupled to a yoke, and a plunger coupled to the yoke for opening and closing a valve, the combination comprising:

• a modified retaining ring threadedly mounted on an internally threaded portion of a housing;
• an operating nut converter threadedly mounted on a threaded operating rod extending within a housing chamber;
• a pressure plate threadedly mounted on said operating nut converter, said pressure plate having an annular recess formed in its underside and a circular recess formed in its topside;
• a swivel plate freely mounted in said pressure plate circular recess for rotational movement therein, said swivel plate having a conically shaped central hub portion;
• a piston ring threadedly mounted on said operating nut converter;
• said housing chamber containing hydraulic fluid for contact with said piston ring;
• a spring mounted at one end on the housing and adapted to fit at the other end within said pressure plate annular recess;
• a bonnet coupled to the housing, said bonnet having an aperture for receiving said conically shaped central hub portion of said swivel plate and a wall provided with a pair of holes in the exterior thereof;
• and
• means removably mounted on said bonnet for exerting a force substantially along the axis of the operating rod to move the rod against said spring and said hydraulic fluid by contacting the central hub portion of said swivel plate.

A fire hydrant including a valve, comprising:

• a bonnet;
• a housing coupled to said bonnet having an internal chamber;
• a threaded operating rod extending within said housing chamber for causing a valve to open and close;
• a spring mounted at one end on said housing;
• power transmitting means threadedly mounted on said operating rod for transmitting power to said rod against said spring;
• hydraulic means operatively associated with said power transmitting means for preventing sudden closing of the hydrant valve;
• and
• swivel means rotatably mounted on said power transmitting means, said swivel means having a contoured portion exposed to the exterior of said bonnet.