US 4,947,672 AGranted

Hydraulic compression tool having an improved relief and release valve

AssigneeBurndy Corporation

InventorsGennaro L. Pecora, John B. Hoover, Steven M. Garramone, Henry Cielesz

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Abstract

A valve for use in a hydraulic compression tool. The valve has a frame with a central chamber, a first inlet, a second inlet and a discharged outlet. A first gate is located at the first inlet. A plunger assembly having a first plunger member and a second plunger member are movably mounted in the central chamber with a spring biasing the plunger member against the second plunger member. The second plunger member has a conduit between the second inlet and the first plunger member. The valve has a first home position that substantially prevents fluid from flowing therethrough. The valve has a second manual release position wherein fluid can flow into the first inlet and out the discharge outlet. The valve also has a third automatic relief position such that in the event a predetermined maximum fluid pressure is exceeded a gate will open between the first plunger and the second plunger member to allow fluid to flow from the second inlet through the valve and out the discharge outlet.

Claims18

Dependent claims

A hydraulic compression tool having a body, a first handle with a fluid reservoir, a second handle, and a compression head having a clamping section, a cylinder, and a ram movably mounted with said cylinder;

said body comprising:
body frame means;
first conduit means for supplying fluid from said fluid reservoir to said cylinder;
hydraulic pump means connected to said first conduit means for forcing fluid into said cylinder;
second conduit means for returning fluid from said cylinder to said fluid reservoir;
and
a combined hydraulic fluid relief/release valve connected to said second conduit means for controlling the flow of fluid in said second conduit means, said valve comprising a valve frame means having a center chamber means with a first inlet aperture means, a second inlet aperture means and a third outlet aperture means;
first gate means at said first inlet aperture means;
and
plunger means movably mounted in said center chamber means, said plunger means having a first plunger member and a second plunger member and forming a second gate means therebetween, said second gate means being located between said
second inlet aperture means and said third outlet aperture means, said valve having a first closed position, a second open position and a third relief position, said first closed position substantially preventing fluid from returning from said cylinder to said fluid reservoir, said second open position allowing fluid in said cylinder to return to said fluid reservoir, and said third relief position allowing a limited amount of fluid to return to said fluid reservoir to prevent a predetermined maximum pressure at said cylinder from being exceeded whereby said valve can allow fluid pressure in said cylinder to be increased to advance said ram towards said clamping section, allow fluid pressure in said cylinder to be released to allow said ram to be retracted from said clamping section, and allow a relief of fluid pressure in said body to prevent the tool from exceeding a predetermined maximum pressure in said cylinder and thereby prevent damage to the tool.

8 more elements

A valve for use in a hydraulic compression tool, the valve comprising:

frame means having a first conduit means with a first inlet aperture means, a second inlet aperture means and a discharge aperture means;
first gate means at said first inlet aperture means, said first gate means having a home position to prevent flow of a fluid therethrough;
plunger means movably mounted in said first conduit means, said plunger means comprising a first plunger member, a second plunger member and means for biasing said first plunger member against said second plunger member in a home position, said second plunger member having a second conduit means between said second inlet aperture means and said first plunger member, said first and second plunger members forming a second gate mean at said second conduit means between
said first and second plunger members, whereby said first gate means and said second gate means can substantially prevent fluid from passing through said first conduit means out said discharge aperture means when said first and second gate means are in a closed home position, when said plunger means is moved to a release position said first gate means is opened to allow fluid to flow in said first inlet aperture means, through said first conduit means and out said discharge aperture means, and when fluid pressure in said second conduit means exceeds a predetermined pressure said first plunger member is moved away from said second plunger member to open said second gate means and allow fluid to flow from said second inlet aperture means, through said second conduit means, through said first conduit means and out said discharge aperture means to provide a combined manual release valve and automatic pressure relief valve.

1 more element

Dependencies are inferred from the claim text.