| 摘要 |
PROBLEM TO BE SOLVED: To solve such a problem that an operation is troublesome in a conventional jack in which an auxiliary screw is rotated for height adjustment, and to provide a jack configured so that a shaft (5) for adjusting a height operates in place of an adjustment screw and a torque shaft (6b) actually lifts a heavy article by a light touch thereto.SOLUTION: A shaft (6) adjusts a gap first, and a torque shaft (6b) actually lifts a heavy article. The switching is automatically operated by a valve (6a) provided at a bottom of the torque shaft (6b). |
