Magnetic fire hydrant guard

In combination with a fire hydrant having a stand pipe on which a bonnet is mounted, and having a valve operating stem extending rotatably through the bonnet and terminating in a nut end above the bonnet, a protective device for the nut end comprising a cylindrically shaped core piece completely encasing the operating nut end and directly and engagably supported by the nut end, and fixedly secured to the nut end by means of set screws threaded through the core piece and seated into shallow holes drilled into the vertical, flat faces of the nut end, and with a square recess built into the center of the flat top of the core piece wherein loosely rests a square steel locking block of a length equal to the depth of the recess in which it rests, said core piece and locking block being surrounded and covered by a sleeve having an inside diameter slightly larger than the outside diameter of the core piece, thereby allowing the sleeve to rotate freely around the core piece;

• an square recess is built into the center of the underside of the top of the sleeve, said recess having the same outside dimensions as the recess built into the top of the core piece, but only half as deep as the recess in the top of the core piece;
• an assembly bolt being engagably and directly supported by the top portion of the nut end, said bolt assembly passes upwardly through a first opening in the center of the core piece and through a second opening in the locking block, and is threadedly secured to the center of the underside of the top of the sleeve, thus assembling the parts of the device into a single unit, and wherein the set screws are secured to the nut end by means of an allen wrench inserted through an access hole in the sleeve after which the access hole is closed by driving a self-threading drive screw into the access hole, thus permanently plugging the access hole preventing further access to the set screws;
• said protective device requires a new access hole to be drilled through the wall of the sleeve at any point centered in a pre-groove cut around the circumference of the sleeve through which an allen wrench can again be inserted to loosen the set screws from the nut end, allowing easy removal of the protective device from the hydrant and preventing unauthorized use of the fire hydrant;
• a self-contained magnetic operating wrench for rotating the hydrant operating stem, the locking block lies completely within the recess in the top of the core piece leaving the sleeve free to rotate around the core piece without turning the hydrant operating stem prior to the mating of the operating wrench with the sleeve, when the self contained magnetic wrench is mated with the formed top of the sleeve, magnetic attraction draws the locking block up into the square recess in the underside of the top of the sleeve slidably along the assembly bolt, a distance of half its length, leaving the remaining half of the locking block within the recess in the top of the core piece, wherein any turning action of the magnetic operating wrench imparts a similar turning action to the sleeve, locking block, core piece, nut end and operating stem which activates the flow control valve upon removal of the magnetic wrench the locking block will gravitationally drop back into its original position within the recess in the top of the core piece slidably along the assembly bolt, thereby leaving the hydrant inoperable until the magnetic wrench is reapplied.