Braking apparatus

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. The braking action is effected by transferring the energy of the rotating sprocket assembly into the oscillation of the torsional springs, and then from spring oscillation into heat by means of damping. The braking apparatus accomplishes a consistent braking torque essentially independent of friction by first loading the torsional spring, then decoupling the loaded spring from the braking torque. The decoupled spring is then allowed to dissipate its stored energy by self-damped oscillation at a rate that does not affect the braking torque. A specific degree of braking is provided by employing the adjustment means to adjust the separation distance between the sprocket assembly and the hub assembly, and thus the separation distance between the rollers and the torsional springs, thereby adjusting the amount of engagement between the rollers and the torsional springs. Applications of the braking apparatus include any service in which a compact, lightweight, mechanically reliable, smoothly-operating, and adjustable braking apparatus is required.