Locking fastener device

A fastener unit including, in combination, a rotary threaded fastener member having a central axis and a clamping surface extending generally perpendicularly to the axis, the clamping surface including a plurality of ratchet-type cogs spaced circumferentially thereabout, each cog including a camming surface extending at an acute angle in one direction to a plane extending perpendicular to the central axis, a substantially flat abutment surface extending upwardly from the camming surface to said plane and substantially perpendicular thereto, the bottommost edge of each cog extending in a plane substantially perpendicular to the central axis of the fastener, a sheet metal lock washer operatively associated with said clamping surface including an annular body concentric with the axis of the fastener member and a plurality of integral circumferentially spaced teeth, each tooth being twisted from its root to free extremity about an axis extending generally radially from the annular body, the teeth in composite being generally frustoconical in an unstressed state so that initial compressive forces on the unit will axially deflect the inner region of the lock washer downwardly creating a spring force in the unit while bringing the upper edges of each tooth into operative association with the perpendicularly disposed bottom edges of the cogs, the transverse cross-sectional configuration of each tooth, taken across said axis extending radially from the annular body, including a central region and a pair of side edge marginal regions, each marginal region being formed in opposite directions out of the plane of the central region with the marginal region closest to the clamping surface of the fastener member being formed upwardly toward said clamping surface, so as to extend generally perpendicular to said plane extending perpendicular to the central axis when the washer is in an unstressed condition, said marginal surface adjacent the upper edge being a radially extending tab sheared from the tooth adjacent the root thereof presenting a connection to the remaining portion of the lock washer along a line which is substantially radial thus creating a cantilever spring when engaged by the cogs.