| 摘要 |
PURPOSE:To provide a securing device which is inexpensive to manufacture and reliably operated, by a method wherein a stopper is supported to a moving frame by means of a cylinder device so that it is movable vertically and in the direction of a rack located to a cord. CONSTITUTION:With a cylinder 10 actuated, a stopper 11 is moved in the direction of a rack 6 of a cord 3 within a frame 8. With a cylinder 18 actuated, through vertical movement, within a moving frame 9, of the stopper 11, each of the teeth of the rack 6 is geared with each of the teeth of a rack 11a to secure a working platform 1 to legs 2. When the working platform 1 is stopped in a position where the rack 6 is not geared with the rack 11a, a valve 20 is opened and a hydraulic pump 21 is driven, positioning is effected by vertically moving the stopper 11 so that the forward end of the rack 11a is positioned to the root part of the rack 6. After a valve 22 is opened to form a circuit bypassing a pump 21, valves 23 and 24 are opened to feed an oil pressure to a piping Y, and the rack 11a is moved forward for interlocking with the rack 6. |
