Abstract: A security fastener including a body having a circumferential periphery and an end wall, a curvilinear groove in the end wall, a plurality of circumferentially spaced depressions extending inwardly into said circumferential periphery from said end wall and having a bottom wall and first and second side walls, junctions having radii between the bottom wall and the side walls. One of the side walls extends at a greater angle to the axis of the fastener than the other side wall, which is engaged by the driving tool. A driving tool for driving both the foregoing security fastener and a conventional hexagonal fastener including a body having a bore with a plurality of axially extending splines for selectively engaging either the above-mentioned side wall of the depression of the security fastener or a plurality of sides of the hexagonal fastener.

Abstract: A lightweight lug nut including a grooved body for receiving a wrench, a nose on the body for bearing against a rim, a threaded portion within the body, an enlarged bore between the threaded portion and the end of the body remote from the nose, a chamfer on the end of the body remote from the nose, a chamfered shoulder between the grooves and the nose, a plurality of teats at the remote end extending inwardly toward the enlarged bore, and a cap for mounting at the remote end and including a groove for receiving the plurality of teats.

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 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: 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.