Sheave pulley out of several pieces. The two main "halves" of the pulley can be moved closer together or farther apart, thus altering the operational diameter. The usual construction is some sort of locking collar or set screws to secure the components, one half with a threaded central shaft and one half with a threaded center. By rotating the components one can "screw" the parts closer together or further apart, thus changing the distance between the two halves and allowing the belt to ride higher or lower in the groove. The adjustments are constrained to a specific range of size and
Brake shoe Brake shoe A brake shoe is the part of a braking system which carries the brake lining in the drum brakes used on automobiles, or the brake block in train brakes and bicycle brakes. The brake shoe carries the brake lining, which is riveted or glued to the shoe. When the brake is applied, the shoe moves and presses the lining against the inside of the drum. The friction between lining and drum provides the braking effort. Energy is dissipated as heat. Modern cars have disc brakes all round, or discs at the front and drums at the rear. An