Patent ID: 7473048

Claim:
A coupling apparatus comprising: a pair of structural members each having a spherical support portion formed at an end of a shaft portion, the spherical support portions being identical with one another and having a larger diameter than the shaft portions, a pair of identical cylindrical blocks, each block having an inner spherical supporting recess extending therethrough, each recess receiving one of said spherical support portions therein and being shaped to conform thereto such that each spherical support portion is free for sliding rotation within one of the blocks about a spherical centerpoint, a pair of identical cylindrical couplers each having a first end and second end, each first end having a circular end plate with a circular opening receiving one of the shaft portions therein, the circular openings having larger diameters than the shaft portions and spherical support portions, each second end having a plurality of axially projecting ends defining a plurality of recesses therebetween, each projecting end having a plurality of flat slanting side surfaces slanting less than 90 degrees from an axial direction that is parallel with an axis of symmetry of the blocks and couplers, and a flat end surface perpendicular to the axial direction, such that each projecting end forms a circumferentially extending engaging hook, and the second ends are twistingly engaged with one another forming a bayonet connection with the engaging hooks of one of said cylindrical couplers conformingly received within the recesses of another of said cylindrical couplers to lockingly enclose the spherical support portions and blocks therein preventing axial and radial displacement of the blocks and spherical support portions while allowing the sliding rotation.