Patent ID: 8529609

Claim:
A system, comprising: a screw, wherein the screw comprises a spherical head; and a washer assembly around the head, wherein the washer assembly comprises: a washer, wherein the washer comprises a socket and a ramp, wherein the socket receives the head to form a ball-and-socket joint, wherein the ramp extends partially around the socket between a first end which is outwardly displaced from the socket and a second end which is tangential to the socket, and wherein the ramp comprises a semicircularly dished face, a cap secured to the washer, wherein the cap comprises a ring, wherein an inner diameter of the ring is smaller than an equatorial diameter of the spherical head, and wherein the spherical head is interposed between the ring and the socket, and a ball, wherein the ball is positioned between the face and the head, wherein rotation of the head in a first direction urges the ball along the face toward the first end so that the ball fits loosely between the face and the head so that the screw is freely rotatable relative to the washer assembly, wherein rotation of the head in a second direction urges the ball along the face toward the second end until the ball binds between the face and the head so that the screw and the washer assembly are locked together, wherein the second direction is opposite the first direction.