Abstract: A warm-up valve in a load responsive hydraulic system which connects the pump discharge pressure with the pump compensator while bypassing to reservoir a partial capacity of the pump. When proper reservoir temperature is reached, a thermostatically controlled solenoid closes the warm-up valve causing the pump to return to low pressure standby.

Abstract: Hydraulic "squeeze cylinders" control the size of the discharge orifice on an extrusion baler and are operated by a control circuit that relieves pressure in the cylinders in response to the build-up of a certain predetermined pressure level in the circuit. Pressurized fluid for the squeeze cylinders is supplied by a single-acting pump cylinder that is connected between the plunger head and its pitman rod in such a way as to deliver a charge of pressurized fluid into the circuit on each compression stroke of the plunger. A pilot-operated relief valve is operated by circuit pressure when the latter reaches a predetermined pressure level to block flow from the pump cylinder and open a relief path for fluid in the squeeze cylinders.

Abstract: An improvement to a priority valve which provides priority flow to a priority function, not only directly from a fluid power source, but also from an accumulator when the priority demand exceeds the output of the fluid power source. This priority flow valve also provides flow to one or more secondary functions when the priority flow requirements are satisfied or when the priority flow path is blocked.

Abstract: Hydraulic "squeeze cylinders" control the size of the discharge orifice on an extrusion baler and are operated by a control circuit that relieves pressure in the cylinders in response to the buildup of a certain predetermined pressure level in the circuit. Pressurized fluid for the squeeze cylinders is supplied by a single-acting pump cylinder that is connected between the reciprocal plunger head and its push rod in such a way as to deliver a slug of pressurized fluid into the circuit on each compression stroke of the plunger, the pump drawing in a fresh slug from a reservoir during each retraction stroke of the plunger.

Abstract: An auxiliary hydraulic front wheel drive including a pair of variable displacement pressure and flow compensated motors each connected to individual wheels; the auxiliary drive utilizes a pressure compensated pump source of the existing hydraulic system on the vehicle. The primary accessories run by said pump maintain a priority flow over the auxiliary drive motors since the pressure compensating level of the motors is set slightly below that of the pump.

Abstract: A priority valve utilized in a pressure and flow compensated variable displacement system which supplies priority flow to a priority motor and secondary flow to a secondary motor as long as the priority flow requirements are satisfied or the priority flow path is blocked. The priority valve utilizes the same flow control signal as the system pump including a fixed restriction in the signal line and a relief valve downstream of said restriction, set at a level below the maximum pressure level of the system so that when the priority motor is stopped, flow continues to the secondary motor.