Patent ID: 7121187

Claim:
An apparatus for controlling a fluid power actuator that has a first port and a second port, said apparatus comprising a directional control valve having a sleeve with a longitudinal bore into which an inlet and a first workport open, the directional control valve including a valve spool slidably received within the bore and having a first position in which the inlet is in fluid communication with the first workport, and a second position in which communication between the inlet and the first workport is blocked; and a feedback mechanism comprising a first feedback piston slideably received in a first aperture at one end of the valve spool and forming a first spool cavity there between into which the pressure in the first port is applied, a first pintle engaging the first feedback piston and a first wall adjacent the one end of the bore, a second feedback piston slideably received in a second aperture at an opposite end of the valve spool and forming a second spool cavity there between into which the pressure in the second port is applied, a second pintle engaging the second feedback piston and a second wall adjacent the opposite end of the bore, wherein when pressure in the first port exceeds pressure in the second port a force is produced which tends to move the valve spool from the first position to the second position.