Randall Brimhall
Electrician in Taylorsville, UT

4285641, Aug 25, 1981

Jul 27, 1979

6/061482

Randall L. Brimhall - West Jordan UT

F04B 2100, F04B 3900

417442

A hydraulic pump and valve unit is disclosed which is particularly useful in a system using a hydraulic cylinder for raising and lowering the cab of a truck. The unit includes a pump which is connected to a valve intake chamber which, in turn, opens axially into a flat end of a larger valve chamber. An annular thrust seal is slidably mounted in the valve intake chamber, and spring means biases the thrust seal against the flat end of a valve spool which is rotatably mounted in the valve chamber. The valve spool has a pair of flow passages therein which connect respective ports in the flat end of the valve spool with corresponding ports in the cylindrical surface of the valve spool. The ports in the cylindrical surface of the valve spool register with a second pair of cooperating flow passages which deliver hydraulic fluid under pressure from the unit to a system such as a hydraulic cylinder, and return hydraulic fluid from such system to the unit. The ports in the flat end of the valve spool are adapted to make mutually alternating registry with the opening from the valve intake chamber. A return flow passageway extends from an opening in the end of the valve chamber to a reservoir for hydraulic fluid, and the ports in the flat end of the valve spool are adapted so that when one port is in register with the opening from the valve intake chamber, the other port is in register with the opening to the return flow passageway.