US 5,415,076 A · Hydraulic system having a combined meter-out and regeneration valve assembly

Abstract

Fluid regeneration circuits are useful for filling expanding sides of a hydraulic cylinder with fluid being exhausted from the other side. The currently available circuits pass the excess fluid not needed for filling the expanded side of the cylinder through the directional control valve to the tank such that the directional control valve must be actuated for the regeneration valve assembly to function. A combined meter-out and regeneration valve assembly of the present invention is used in a hydraulic system having a directional control valve for metering in pump to cylinder fluid flow and includes a meter-out valve to meter-out cylinder to tank fluid flow from a head end actuating chamber. The fluid passing through the meter-out valve passes through an exhaust conduit to a tank bypassing the directional control valve. This permits the meter-out valve to be used independently of the directional control valve to retract a hydraulic cylinder. A flow regeneration valve and a pressure boost valve are used in combination with the meter-out valve for providing flow regeneration from the head end chamber to a rod end chamber when fluid pressure in the head end chamber is less than the pressure level of fluid in a passage as determined by a spring of the pressure boost valve.

Claims9

Dependent claims

A combined meter-out and fluid regeneration valve assembly for a hydraulic system having a double acting hydraulic cylinder which has first and second actuating chambers with the first actuating chamber being subjected to load induced pressure, and first and second conduits connected to the first and second actuating chambers respectively, comprising:

a load check valve disposed in the first conduit to permit fluid flow therethrough in a first direction toward the first actuating chamber and blocks reverse fluid flow therethrough;
a remotely controlled meter-out valve having an inlet and an outlet with the inlet being connected to the first conduit between the load check valve and the first chamber, the meter-out valve having a closed position blocking the inlet from the outlet and a variable metering open position establishing variable communication between the inlet and the outlet;
a passage connected to the outlet of the meter-out valve;
and
a flow regeneration valve disposed between the passage and the second conduit and being oriented to permit substantially unrestricted fluid flow from the passage to the second conduit when the fluid pressure in the second conduit is less than the fluid pressure in the passage.

2 more elements

A hydraulic system having a pump, a tank, a double-acting hydraulic cylinder having first and second chambers with the first chamber being subjected to load generated pressure, first and second conduits, a directional control valve connected to the pump, the tank and to the first and second conduits for controlling fluid flow from the pump to the conduits and between the conduits and the tank;

comprising
an exhaust conduit in continuous communication with the tank;
and
a valve assembly mounted to the hydraulic cylinder and having a first passage communicating the first conduit with the first actuating chamber, a second passage communicating the second conduit with the second actuating chamber, a load check valve disposed in the first passage to permit fluid flow therethrough in a first direction toward the first chamber and to block reverse fluid flow therethrough, a third passage in communication with the exhaust conduit, and a remotely controlled meter-out valve having a closed position blocking the first passage from the third passage and a variable metering position establishing variable communication between the first passage and the third passage, the third passage and the exhaust conduit defining a flow path from the meter-out valve to the tank bypassing the directional control valve.

1 more element

Dependencies are inferred from the claim text.

Hydraulic system having a combined meter-out and regeneration valve assembly

Life of this patent

Hydraulic system having a combined meter-out and regeneration valve assembly

Life of this patent

Abstract

Claims9