Tamperproof fire hydrants

Claim 1

A tamperproof fire hydrant comprising: a barrel member having an open end portion; valve means positioned in the lower portion of said barrel member; reciprocating valve stem means extending from said valve means upwardly within said barrel member and having a threaded end portion; a top closure member secured to the open upper end of said barrel member, said top closure member having an aperture therethrough with an inwardly extending shoulder therein and threads positioned outwardly of said shoulder; a rotatable operating nut having a polygonal end portion projecting out of the aperture of said top closure member, said rotatable operating nut having an exterior flange thereon operatively abutting said shoulder in said aperture of said top closure member, said rotatable operating nut having threads thereon cooperating with the upper threaded end portion of said valve stem means whereby said nut member can be rotated to actuate said valve stem means; a tubular hold-down nut threaded into said apertured top closure member and operatively abutting said exterior flange of said operating nut to position said operating nut against axial movement, said hold-down nut having a portion extending out of said top closure member, said outwardly extending portion having a frusto-conical outwardly facing surface provided with at least two inwardly axially extending and circumferentially spaced holes; a retaining ring groove extending about said polygonal end portion of said operating nut; an annular retainer member having an inside diameter sufficient to loosely fit over and rotate relative to said polygonal end portion of said operating nut, said annular retainer member having a bottom face with at least a pair of upwardly axially extending and circumferentially spaced holes, said retainer member further having an external peripheral threaded surface and an upper face with an annular recess extending about an inner periphery thereof; a retaining means loosely carried in the annular groove on said polygonal upper portion of said operating nut, said retaining means bearing loosely in said recess on said upper face of said retainer member to prevent axial movement of said retainer member outwardly therefrom; and a dome shaped cap covering the operating nut having a skirt depending downwardly therefrom with an interior threaded surface for cooperating with the exterior threaded surface of said retainer member, said dome shaped cap when threaded onto said retainer member being freely rotatable relative to the polygonal portion of said operating nut with a lower edge of said skirt permitting only limited access to said polygonal end portion, said holes in said hold-down nut and said holes in said retainer member.