| 摘要 |
PURPOSE:To simplify the speed control structure by disposing the first cylindrical piston capable of moving for a designated distance and the second piston which is fitting to the first piston and projected out of a hydraulic cylinder in the hydraulic cylinder. CONSTITUTION:The first hydraulic piston 2 is movably disposed 1 a cylinder chamber (i) of a hydraulic cylinder main body 1a. The base end side of the second piston 3 is fitted in the first piston 2, and the forward end side of the second piston 3 is projected outside the hydraulic cylinder 1. When oil is supplied to an oil pressure port 6, both the first piston 2 and the second piston 3 operate, and the second piston 3 is projected at low speed. When the cylindrical first piston 2 is stopped, the second piston 3 is projected quickly. Accordingly, the projecting operation speed of the piston can be changed without operation for switching a hydraulic selector valve so as to simplify the speed control structure.
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