Abstract: In a fluorescent light fixture having a panel for supporting thereon an electrical socket assembly for holding a fluorescent tube, a simple, mechanical, manually-effected interlock for securing the socket assembly in a tube-receiving and supporting mode on the panel. The panel itself is formed with a non-rectangular cut-out zone for receiving an upwardly extending wall of the socket assembly inserted upwardly through the cut-out zone, and a base of the socket assembly being then shiftable arcuately to effect interengaging intercoupling between a laterally-opening slot in the base of the socket assembly and a projecting edge of the panel bounding the cut-out zone formed therein. A dimple-like deformation formed in the panel on an underside thereof defines a detent to deter inadvertent mechanical separation of the socket assembly from the panel.

Abstract: This mechanical joint allows relative rotation of two articles (one may be a stationary fixture), on an arbitrary axis. The joint has as much angular-rotation range as a hinge, but as many degrees of freedom as a ball-and-socket or universal joint. It allows transmission, between the objects, of force or flux (e.g., of electricity, gas, or liquid), or both. In can be used as an applied-force or motion sensor, varying electrical contacts or conductivity in response to relative motion or force applied between the articles. In one form the invention is simply a mechanical joint formed of two closely interlocked toroids. The minor cross-section of each toroid is sized to just fit through the central aperture of the other; there is a connection point on each toroid for attachment of one article. By adjusting closeness of fit, a designer can impart to the device a wide range of desirable frictional properties.