| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a lowering device at the time of power abnormal stopping of a long front in a work machine with a long front, in which the front is lowered to posture a rest attitude at the time of power abnormal stopping. <P>SOLUTION: Hydraulic oil ducts 35, 37, 39 between oil chambers 7b, 9b, 12b in which oil pressure is generated respectively by the dead weight of each arm 8, 11, 14 and control valves 26A, 26B, 27, 28A, 28B, and an oil tank 24 are connected by emergency hydraulic oil ducts 43, 44, 45, respectively. Opening and closing valves 47, 48, 49 are provided in the emergency hydraulic oil ducts 43, 44, 45, respectively. The opening and closing valve 49 of the emergency hydraulic oil duct 45 corresponding to the upper side arm, and then the lowermost opening and closing valve 47 are successively opened and closed by a controller 61, and the working fluid between a bottom chamber of a hydraulic cylinder corresponding to each arm and a rod chamber is circulated to successively lower the arms 14, 11, 8, and the front is rendered to posture a rest attitude. <P>COPYRIGHT: (C)2012,JPO&INPIT |
