| 摘要 |
An adjustable mechanism for supporting an article, particularly for use with an article transportation system, is disclosed. The support mechanism includes a closed cylinder having a movable piston disposed therein. The piston divides the interior of the cylinder into upper and lower closed chambers. A pair of oppositely oriented pressure relief valves are disposed in the piston to selectively permit fluid communication between the upper and lower chambers. The pressure relief valves open only when the pressure differential exerted thereacross exceeds a predetermined value such that the piston is normally locked in position within the cylinder. A first rod is connected to the piston and extends upwardly out of the cylinder. An article engaging platform is secured to the upper end of the upper rod. A second rod is also connected to the piston, extending downwardly out of the cylinder. The lower rod cooperates with a fixed guide to urge it upwardly or downwardly, as desired to raise or lower the platform relative to the cylinder. The guide may be adjustably supported to permit easy adjustment of the relative height of the platform.
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