| 摘要 |
PURPOSE: A length-adjustable compression spring is provided to secure more flexible use and to make a piston rod movable relative to a casing even when the compression spring is blocked. CONSTITUTION: A compression spring comprises a casing(1) with a piston(12) mounted on a piston rod(8) being disposed for displacement therein. Two sectional casing chambers(15,16) are provided in the casing, which are filled with pressure fluid and at least one of the sectional casing chambers is defined by the piston. A control valve(20) interconnects the sectional casing chambers in an open position and blocks the compression spring in a shut-off position. By way of an additional automatic valve between the sectional casing chambers, the compression spring, even when blocked, is adjusted in a piston-rod expansion direction(36a) by a force comparable to the expansion force that works in the expansion direction by the pressure of the pressure fluid.
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