(under the class definition) Apparatus in which the pump or means for transmitting motion to the pump from a source of power is provided with control means for either (1) interrupting motion of the pump (e.g., clutch, lock, etc.), (2) varying the rate of motion of the pump (e.g., brake, dashpot, adjustable gearing, etc.), (3) changing the swept volume of displacement of an expansible chamber-type pump, or (4) changing the volumetric capacity of an expansible chamber- type pump (e.g., clearance control); said control means being operable in response to the level of pump fluid.
