Abstract: A variable displacement vane type pump having a pivotally mounted ring member controllable to vary the eccentricity between the rotor and the ring thus controlling the pump displacement. The ring is positioned on the pivot such that the center thereof is always located in one quadrant relative to axes through the pivot point and the center of the pump rotor to continually maintain the net ring reaction force, due to internal pressure, directed to one side of the pivot connection in opposition to the displacement control pressure, which is impressed on a portion of the outer surface of the ring, whereby control stability throughout the displacement range is improved.

Abstract: A control mechanism for a disc-type friction device having a fluid operated piston including a valve member slidably disposed in the piston. The valve member is maintained in abutment with one of the disc members. The valve member is operatable to control the distribution of fluid pressure to and from the apply chamber of the friction device so that the piston is maintained at a predetermined distance from the disc member abutted by the valve member whenever the friction device is disengaged.