| 摘要 |
<p>PURPOSE: To minimize the chance of a hydraulically driven lift device from collapsing upon a break in a hydraulic input line to a cylinder driving the lift device, by a relief valve installed with a hydraulic fuse. CONSTITUTION: This relief valve 60 comprises a valve seat 105 energized in a first direction by a relatively heavy spring 96 and a hydraulic fuse energized away from the valve seat 105 by a relative light, second spring 120. Upon a break occurring in a hydraulic input line, back pressure energizes the hydraulic fuse to seat against the valve seat 105, thus closing the relief valve 60. Upon applying additional hydraulic pressure in the direction of the hydraulic fuse, the valve seat 105 disengages from the hydraulic fuse, allowing operating fluid to flow through the relief valve 60 and thus allowing a position in a cylinder to retract so as to permit lowering of the lift device.</p> |
