Patent US 4,130,049

A fluid source for delivering fluid to a control valve having Float, First direction and Second direction positions. A piston-bore check valve allows flow to the motor and normally blocks reverse flow, the piston having its first end biased against a seat. A control chamber communicates with the piston's second end. Flow is restricted between the motor's first end and the control chamber and there is a full flow path between the motor's first end and the bore to provide a force acting against the piston's first end. The control chamber connects with a sump. A drain valve entry port communicates with the motor's first end and an exit port thereof communicates with the sump to provide either entry port-exit port connection or blocking. A mechanism moves responsive to shifting of the control valve to shift the drain valve to connect the entry and exit ports when the control valve is in a Float or a Lower position and to block such connection in a Raise or Neutral position.