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US 5,309,936 AGranted
Poppet configuration for counterbalance valve
AssigneeDana Corporation
InventorNorman B. Christensen
Life of this patent
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AssigneeDana Corporation
InventorNorman B. Christensen
Estimating the term…
A counterbalance valve has a first port connected to a hydraulic cylinder and a second port connected to a four-way controller, such as a four-way control valve. Disposed between the ports is a poppet biased to a closed position. The poppet opens to allow operating hydraulic fluid to drain from the hydraulic cylinder and also opens if excessive pressure builds up in the hydraulic cylinder due to thermal conditions. When an operator decides to move the piston within the hydraulic cylinder, hydraulic fluid must be drained from the cylinder. This is accomplished by moving the poppet from a blocking position to an open position with pressurized pilot fluid. On occasion, confusion caused by operator error can cause a build-up of valve backpressure from the four-way control valve, which prevents the poppet from moving upon applying pilot pressure thereto. The resulting excess pressure in the hydraulic cylinder can rupture the hydraulic cylinder. In order to minimize the chances of a rupture, the poppet is provided with a longitudinal bore extending therethrough. The bore allows backpressure from the four-way controller to be passed through the poppet so as to be applied to both ends of the poppet. Consequently, increases in valve backpressure have a corresponding increase in the relief setting. This minimizes a multiplier effect which could occur upon attempting to advance a piston while the four-way controller is inadvertently in a retracted mode.
In a counterbalance valve assembly having at least one counterbalance valve, wherein the counterbalance valve is disposed between a first port for connecting the counterbalance valve to a hydraulic cylinder and a second port for connecting the counterbalance valve to a controller;
The improvement of claim 7, wherein the internal valve comprises a chamber with first and second valve seats at opposite ends thereof and a ball within the chamber, wherein pilot pressure from pressurized pilot hydraulic fluid closes the bore by forcing the ball against the first seat while backpressure from hydraulic operating fluid forces the ball against the second seat, allowing the hydraulic operating fluid to flow from the second surface of the poppet through to the first surface of the poppet.
A poppet for use in a counterbalancing valve arrangement, wherein the counterbalancing valve arrangement has a pilot fluid chamber, first and second ports for passage of hydraulic operating fluid, and a valve seat and wherein the poppet is biased by a spring to block passage of hydraulic operating fluid from the first to the second port, the poppet comprising:
Dependencies are inferred from the claim text.