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.
In a hydraulic control apparatus for at least one doubleacting consumer of the type wherein at least one control valve 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 said 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 said first line from said conduits, and wherein said valve member of said control valve controls the flow of fluid in a control conduit for a switchover valve which opens in response to fluid flow in said control conduit to provide a path for the flow of pressurized fluid from said supply conduit into a second fluid-conveying line of said consumer, and wherein pressure-regulating means is connected between the outlet of said switchover valve and said tank and is operative for regulating the pressure of fluid in said second fluid-conveying line of said consumer, the improvement consisting in that said pressureregulating means comprises a flow restrictor connected between the outlet of said switchover valve and said tank and a check valve connected in parallel to said floW restrictor with such an orientation as to permit flow of fluid from said tank into said second fluid-conveying line of said consumer.
Claim 2
Dependent Claim
221 words
In a hydraulic control apparatus for at least one doubleacting consumer of the type wherein at least one control valve 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 said 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 said first line from said conduits, and wherein said valve member of said control valve controls the flow of fluid in a control conduit for a switchover valve which opens in response to fluid flow in said control conduit to provide a path for the flow of pressurized fluid from said supply conduit into a second fluid-conveying line of said consumer, and wherein pressure-regulating means is connected between the outlet of said switchover valve and said tank and is operative for regulating the pressure of fluid in said second fluid-conveying line of said consumer, the improvement consisting in that said pressureregulating means comprises a flow restrictor connected between the outlet of said switchover valve and said tank and a check valve connected in parallel to said floW restrictor with such an orientation as to permit flow of fluid from said tank into said second fluid-conveying line of said consumer.
Claim 3
Dependent Claim
19 words
The apparatus defined in claim 1, wherein said pressure-regulating means consists of said flow restrictor and said check valve.
Claim 4
Dependent Claim
50 words
The apparatus defined in claim 1, wherein said apparatus further includes a pressure-limiting valve connected between said supply conduit and said tank for limiting the pressure of fluid in said supply conduit, and wherein the inlet of said switchover valve is connected to and receives fluid from said supply conduit.
Claim 5
Dependent Claim
28 words
The apparatus defined in claim 3, wherein said pressure-limiting valve and said flow restrictor and said check valve are incorporated in a common housing provided as a module.
Claim 6
Dependent Claim
16 words
The apparatus as defined in claim 1, wherein said flow restrictor is an adjustable flow restrictor.