Patent ID: 7261506

Claim:
A spring action joint having at least two parts comprising, a threaded part having a body with two opposed sides and a circular series of ramp structures on at least one of the two opposed sides, and a first washer having a body with two opposed sides, an outer periphery, a central aperture, and a circular series of ramp structures in the form of ratchet teeth on at least one of the two opposed sides of the first washer, the body of the washer being resiliently deformable at least up to when it is subjected to a joint preloading force created by tightening the joint up to a preloaded state, a ratchet mechanism including the ratchet teeth, the ratchet mechanism allows relative movement between the joint parts in a direction which causes tightening of the spring action joint but resists movement in the opposite direction, wherein the joint has an engaging zone for applying the preloading force to a work-piece, the engaging zone being disposed on or adjacent to an outer periphery of substantially concave shaped surface.