Abstract: A multi-part locknut including a locknut body, a locknut head having an endless curvilinear key-receiving groove therein secured to the locknut body, and a locknut sleeve rotatably mounted on the locknut body and held in position between portions of the locknut head and locknut body.

Abstract: A manhole cover locking bolt construction for locking a manhole cover to an associated frame including a bolt having a threaded shank and an externally threaded head and an endless curvilinear groove in the top of the head for receiving a key of mating configuration for threading the bolt into and out of the manhole cover frame, and a cap for threadably mounting on the externally threaded head to protect the curvilinear groove against entry of foreign matter.

Abstract: A pipe plug which cannot be removed from a pipe with the same key with which it is installed, the pipe plug having a body with a plurality of arcuate grooves having inclined arcuate ramps leading from its face into its body and terminating at shoulders for abutting engagement with first key having pins which bear against the shoulders to tighten the plug in the pipe but which cannot loosen the plug because the pins will ride up the ramps and cam out of engagement with the plug, and a second key for removing the plug including a ridge on the second key for mating with a complementary curvilinear groove in the plug. A counterbore is provided in the face of the plug to receive portions of the ridge which are of substantially the same diameter as the counterbore to thereby center the second key with respect to the plug and guide it while the second key is rotated until the ridge thereon falls into the groove to effect mating engagement therewith.

Abstract: A tamper-proof bolt including a shank with a threaded end portion merging into an unthreaded portion of lesser diameter merging into an enlarged unthreaded portion merging into the larger base of a frustoconical head also having a smaller base, an undulating curvilinear groove in the smaller base, an island having lobes within the groove, an outer side in the groove, an inner side in the groove formed by the sides of the lobes of the island, and a cylindrical boss on the island extending axially outwardly from the smaller base and having a radial dimension which is approximately equal to the minimum radial dimension of the undulating groove.

Abstract: A locknut key including a key body, a key shroud mounted on the key body and a key member mounted on the key body within the shroud, the shroud extending for a substantial distance beyond the key to guide the key over the outer surface of a locknut which is to be turned by the key. A wrench-locknut key combination including a wrench having a shank, a U-shaped spring clip secured to the shank, a groove on the locknut key for receiving the U-shaped spring clip, and an elongated tie member for attaching the locknut key to the spring member.

Abstract: A combination of a locknut and key therefor, the locknut including a body portion having a face thereon and a curvilinear groove of predetermined configuration in the face, a thread on the body portion, the thread including a frustoconical lead-in portion terminating at an extremely short cylindrical helical thread portion, a key housing having an internally threaded end portion which can be centered on the lead-in portion and thereafter threaded onto the cylindrical threaded portion of the locknut, the key having a key head with a flange of curvilinear configuration for mating engagement with the groove in the locknut, the key head being mounted on a shank on which the housing is rectilinearly slidable, a spring in the housing for biasing the key head toward the locknut when the housing is centered on the the locknut and which forces the flange into the groove as the housing is threaded onto the locknut, and a wrench-receiving head on the shank for turning the key head after the housing is securely mounted o

Abstract: An operating nut construction for a fire hydrant including a body member having a lower tapped portion for threadably receiving a fire hydrant valve rod, a sleeve rotatably mounted on the body member against axial movement, a cap rotatably mounted on the body member against axial movement, a narrow gap between the sleeve and the cap, and a plurality of shallow depressions in the body member aligned with the gap for reception of a specialized wrench having narrow shoulders thereon to turn the body member. The rotation of the sleeve or the cap or both will not turn the body member because they are rotatably mounted thereon.

Abstract: A locknut having a body portion with an outer surface and first and second ends, a thread extending inwardly into the body portion from the first end, a depression in the second end, an inwardly tapered lobed curvilinear surface defining the periphery of the depression for receiving a mating key, and an external thread extending from the second end onto the outer surface for receiving the internally threaded surface of a sleeve mounted on a key for attaching the key to the locknut. The locknut as described above including a rotatable sleeve mounted thereon with a shroud located radially outwardly of the external thread. A locknut as described above wherein the outer surface extending from the first end is frustoconical and terminates at an annular shoulder which is located radially outwardly of the external thread.

Abstract: An obstructing plate construction for a tank having an opening in a top wall thereof and a cover with a base plate having an opening aligned with the opening in the top wall, the obstructing plate construction including an adapter plate mounted between the base plate and the top wall, bolts permanently affixed to the adapter plate for receiving nuts at the underside of the top wall, an opening in the adapter plate aligned with the opening in the top wall and the opening in the base plate, a plurality of nut and bolt assemblies extending through the base plate, adapter plate and top wall for securing them in assembled relationship, an obstructing plate, and locking bolts for selectively securing the obstructing plate to the adapter plate in obstructing relationship to aligned openings in the base plate, adapter plate and top wall.

Abstract: A locking valve construction including a housing, a valve member in the housing, a fluid inlet and a fluid outlet in the housing, a valve member rotating key for rotating the valve member to an open position for selectively effecting communication between the fluid inlet and the fluid outlet, a holding member effectively mounted on the housing for holding the housing against rotation relative to a base when the valve member is being rotated by the valve member rotating key, and mounting structure for mounting the housing on the base for permitting the housing and the valve member to rotate as a unit in the event that the holding member is rendered inoperative to thereby prevent movement of the valve member relative to the housing to an open position.

Abstract: A diesel engine fuel supply system having an injector pump, a fuel tank, a fuel inlet conduit between the fuel tank and the injector pump and a fuel return conduit between the injector pump and the fuel tank, a venting fuel valve including a valve body, an adapter for mounting the valve body on the injector pump, a fuel inlet on the valve body for receiving the fuel inlet conduit, a fuel outlet on the valve body for transmitting fuel to the injector pump, a vent in the valve body in communication with the atmosphere, a valve spool in the valve body movable to a first position for effecting communication between the fuel inlet and the fuel outlet to supply fuel to the injector pump while preventing venting of the fuel outlet to the atmosphere through the venting means, and the valve spool being movable to a second position for preventing communication between the fuel inlet and the fuel outlet and for effecting communication between the injector pump and the atmosphere to thereby vent the injector pump and pre

Abstract: A locking valve construction including a housing, a valve member in the housing, a fluid inlet and a fluid outlet in the housing, a valve member rotating key for rotating the valve member to an open position for selectively effecting communication between the fluid inlet and the fluid outlet, a holding member effectively mounted on the housing for holding the housing against rotation relative to a base when the valve member is being rotated by the valve member rotating key, and mounting structure for mounting the housing on the base for permitting the housing and the valve member to rotate as a unit in the event that the holding member is rendered inoperative to thereby prevent movement of the valve member relative to the housing to an open position.

Abstract: A bolt type of lock structure including an elongated bolt member, first and second externally threaded ends on the bolt member, first and second nuts of frustoconical configuration threadably mounted on the first and second threaded ends, first and second faces on the nuts for receiving key members for tightening and loosening the nuts, an anaerobic thread locking compound on the threads, the bolt member being relatively soft throughout to withstand impact and having a hardened zone in a central area wherein it is exposed to chiseling or sawing. A nut of the type described above including a threaded bore in the face which receives a screw for securing the key member thereto. A stud having oppositely threaded ends and an irregular axial bore in one end for receiving a wrench and a hardened surface portion between the threaded ends.

Abstract: A rim mounting construction including a hollow hub mounting shaft having an apertured annular flange for mounting on rim mounting lugs, a spoked rim having a hub, interfitting splines on the hub and the hub mounting shaft, a hub securing nut having a shoulder for bearing against the hub and a threaded connection with the hub mounting shaft so that the shoulder will bear against the hub to retain it in position on the hub mounting shaft when the first threaded connection is tightened, a locking nut secured within the hub mounting shaft, and a locking bolt having a second threaded connection with the locking nut and having a head with a surface for bearing against the securing nut after the second threaded connection is tightened, the first and second threaded connections being of opposite hand whereby an attempted unthreading of the first threaded connection will result in a tightening of the second threaded connection to thereby prevent loosening of the securing nut, the head of the locking bolt having a curv

Abstract: The present disclosure provides means for locking the engine compartment hoods of vehicles by a device which is detachably secured to the fixed vehicle body structure below a side edge of the hook and has a threaded upward extension which projects upwardly between the edge of the hood and the vehicle body structure. A nut engages the threads of the upward extension and overlies a side edge of the hood to prevent opening the hood. A specially keyed wrench is required to remove the nut and thus release the hood lock.