Fire hydrant cap and actuating tool therefor

A fire hydrant cap for a fire hydrant outlet being mounted to an removed from said hydrant outlet by a specialized tool, said cap comprising:

• a body having a domed surface formed of a carbon steel forging and heat treated to a Rockwell "C" hardness at least in the range of 50-62, the body having an internal surface and external surface;
• the internal surface of the body having internal threads extending inwardly into the body for attachment to said fire hydrant outlet, the internal surface also including an annular shoulder therein;
• a cadmium plated steel lock washer in the form of a split ring seated against the internal shoulder;
• the external surface extending around and over the internal surface and having a curved, convex shape;
• a plurality of tool engaging surfaces disposed thereon and spaced from each other and positioned on the external surface, each tool engaging surface including a shoulder facing oppositely to the direction in which the cap is threaded onto said hydrant outlet for providing shoulders for engagement by a tool having complementary surfaces for cooperative engagement with said tool engaging surfaces for tightening said cap to said hydrant outlet when torque is applied to said tool;
• each engaging surface including a recess extending from the shoulder in a direction opposite the direction in which the cap is threaded onto the hydrant, each of the recesses including a curved surface progressively increasing in distance from the axis of the body and including a side wall which extends parallel to the longitudinal axis of the cap for coacting with said tool complementary surfaces for unthreading the cap from said hydrant outlet;
• an externally facing annular groove in the external surface adjacent a portion of the cap where the external and internal surfaces meet;
• a slip ring forged of carbon steel and having an internally facing annular groove in alignment with the externally facing annular groove in the external surface of the cap, said slip ring having a back surface for engaging a selective gripping means disposed on said tool;
• and
• a spring steel snap ring in registration with both grooves to secure the slip ring on the cap in rotational relation therewith, and said selective gripping means cooperating with slip rings of different size caps mounted on said hydrant outlet to prevent said tool complementary surfaces from slipping off of said tool engaging surfaces when torque is applied to said tool for tightening and removal of said cap to and from said hydrant outlet.