Hydraulic control apparatus for hydraulic-lift end gates of moving vans and the like

Abstract

Abstract The apparatus controls at least one double-acting hydraulic consumer, such as a hydraulic-lift end gate of a moving van, or the like. The apparatus includes at least one valve member movable between first operative, second operative and neutral positions to thereby respectively connect a first fluid-conveying line of the consumer with a supply conduit which is connected to a source of pressurized fluid, with a return conduit which is connected to a tank, and to seal the first fluid-conveying line of the consumer from the supply and return conduits. The valve member of the control valve also controls the flow of fluid in a control conduit for a switchover valve which opens in response to fluid flow in the control conduit to provide a path for the flow of pressurized fluid from the supply conduit into a second fluidconveying line of the consumer. A pressure-regulating unit is connected between the outlet of the switchover valve and the tank, and is operative for regulating the pressure of fluid in the second fluid-conveying line of the double-acting consumer. The pressure-regulating unit is provided in the form of a flow restrictor connected between the outlet of the switchover valve and the tank and a check valve connected parallel to the flow restrictor with such an orientation as to permit flow of fluid from the tank into the second fluid-conveying line of the doubleacting consumer.

Inventors

• 👤 Walter Herrmann

Bibliographic Details