Abstract: DANA 90 A load sense pressure controller used with a hydraulic control valve such as a hydraulic direction control valve includes a body in the form of a barrel having a threaded first end and a threaded second end. An externally threaded first plug is threaded into the first end of the body and an externally threaded second plug is threaded into the second end of the body. Both first and second plugs each have passages therethrough wherein the passage through the first plug is connected to the load sense passage from a valve and the passage through the second plug is connected to a tank passage in the control valve. Disposed between the first and second plugs is a piston which is biased by a coil spring toward the first plug. The piston has a stepped axially extending passage extending therethrough which is intersected by a radially extending passage.

Abstract: Material such as trash or refuse is packed in a container by opposed hydraulic packing and ejecting cylinders. Each cylinder is controlled by a hydraulic control valve with the control valve controlling the ejecting cylinder being, in effect, operated by the control valve for the packing cylinder. This is accomplished by sensing the pressure applied to the packing cylinder and when the pressure reaches a predetermined level, a pilot dump valve, in the ejecting cylinder is opened to allow the piston in the ejecting cylinder to retreat. When the pilot pressure drops below the predetermined level, the pilot dump valve closes, allowing the packing cylinder to exert additional packing force. In this way the piston in the ejecting cylinder inches back and the material is intermittently packed. An anti-cavitation check is provided so as to fill the chamber of the ejecting cylinder as the piston retracts.

Abstract: An improvement in and method of operating a load sensing system in which a variable displacement, pressure compensated pump delivering hydraulic fluid to a fluid operating device through a directional control valve is controlled by a load-sensing system pressure limiter which is set so that the system operates at the maximum continuous system operating pressure. By also setting pump destroke pressure slightly higher than the necessary operating pressure for the load, optimum performance of the pump is realized. The load-sensing system pressure limiter is configured as a poppet which is placed inside of the body of the directional control valve and is biased by an adjustable spring force to the closed position. Preferably, the poppet connects the load sensing core of the directional control valve to an exhaust passage therein so as to require minimal modification of the directional control valve.

Abstract: Response times for a remote hydraulic control system having control lines from a remote controller to a main control valve of 50 feet or more are reduced by providing actuator pistons which are operated at a second pilot hydraulic pressure less than a first pilot hydraulic pressure used for moving a valve spool within the main control valve. The actuator pistons open valves which allow hydraulic fluid at the higher pilot pressure to push the valve spool. "Off" times are further reduced by continuously bleeding off a portion of the hydraulic fluid applied to the actuator pistons at the second hydraulic pressure.