A winding machine, useful as an air hoist, includes a winding portion about which a chain is wound, and from which articles are hung for loading and/or unloading thereof. The winding machine is rotationally powered by an air driven motor controlled by an air supply valve which regulates the supply of air to the motor by virtue of a built-in variable shuttle valve. An operation unit pneumatically biases a main spool in the shuttle valve in a desired direction and to a selected extent to provide, respectively, rotation in normal and reverse directions, by permitting adjustable flow-through of air from a supply line. A rotation suspending mechanism includes an air activated braking mechanism, normally biased to provide braking of the motor when not actively being rotationally operated. The braking mechanism is connected through a variable aperture to the air supply, such that sufficient air pressure provided thereto overcomes the biasing thereof. The opening in the variable aperture is determined by operation of a braking valve in communication with the operation unit via air flow passages, to variably operate the braking valve based upon flow of air through the shuttle valve of the operation unit, thereby disengaging the brake mechanism when sufficient air pressure is supplied to rotate the air driven motor.