Abstract: A vehicle unloader particularly adapted for unloading trucks and trailers used to transport sugar cane, which comprises a sloping jib, a lifting mechanism consisting of a motor, a pulley mounted at one end of the jib, a first cable passing over the pulley and attached to a hook, and a hook positioning system consisting of a second cable attached to the hook and the jib, a cylinder for varying the tension of the second cable, a three-position selector having a first position causing the cylinder to move so that the hook is brought towards the jib, a second position causing the cylinder to move so that the hook is allowed to move in the opposite direction away from the jib and a third position causing the cylinder to be isolated; a power source; and a control unit the operation of which is dependent on the amount of power absorbed by the motor of the lifting mechanism and which connects the cylinder to the power source and ensures that it is supplied with reduced power from the source when the hook is loaded an