Abstract: A braking apparatus for imparting constant mechanical torque to effect a braking action is capable of operating in a constant, smooth, and adjustable manner, yet operates essentially independent of friction and temperature, as well as independent of rotational speed. The braking apparatus includes a hub assembly having a hub, a collar, a plurality of torsional springs, a spring cap, a spring bushing, and damping means, and a sprocket assembly having a sprocket, a hub bearing, a retaining ring, and a plurality of roller assemblies each of which has a roller. The sprocket assembly is rotatably connected to the hub assembly by a hub assembly spring, a sprocket assembly spring, an adjustment cap, and an adjustment means. The apparatus provides braking by releasably contacting at least one of each of the rollers with at least one of each of the torsional springs so as to deflect and then release the torsional spring as the sprocket assembly rotates about the hub assembly.

Abstract: A bearing system providing redundancy of bearing function. An inner race and an outer race are concentric and axially spaced apart from one another. A bearing set includes a pin of individually rotatable bearing wheels. The wheels are mounted by an intermediate retainer. A selector is provided to restrain either of the races from rotation relative to its respective wheel, thereby providing for selection of which race is to be active in providing relative rotation of the races.