TIMBERING JACK DOWN DEVICE

摘要

PROBLEM TO BE SOLVED: To jack down a timbering by an inexpensive device noiselessly with high safety. SOLUTION: This timbering jack down device includes a reaction force receiver 11 for a hydraulic cylinder 10 and a ratchet wheel 12 attached to the handle of a screw jack not to rotate therearound. The reaction force receiver 11 is supported on a horizontal member while being non-rotatably locked to a strut for timbering to the upper end with the screw jack attached. The base end of the body of the hydraulic cylinder 10 is rotatably supported on the reaction force receiver 11. A ratchet claw engagement element 32 engaged with the ratchet claw 31 of the ratchet wheel 12 is attached to the front end of the extending/retracting shaft 10a of the hydraulic cylinder 10. By extending and retracting the shaft 10a of the hydraulic cylinder 10, the ratchet claw engagement element 32 is engaged with the ratchet claw 31 during the extension, and the ratchet wheel 12 is rotated in the jack down direction. COPYRIGHT: (C)2011,JPO&INPIT