| 摘要 |
PROBLEM TO BE SOLVED: To provide a pile driver capable of avoiding interruption of excavating operations by preventing the coming-off of a driving-side sprocket from an output shaft of a hydraulic motor by a simple structure while enhancing the locomotive faculty of a working device. SOLUTION: A working-device raising and lowering means 3 of the pile driver, which hoists and lowers the working device, moving up and down along a leader 1, via a chain 10, includes: a pair of hydraulic motors 5 and 5 which are arranged in an opposed manner by aligning the output shafts 4 and 4 with each other in the lower portion of the leader 1; the driving-side sprockets 6 and 6 which are connected to the output shafts of the hydraulic motors, respectively, and held by a holding member 8; and an annular member 9 which is sandwiched between both the driving-side sprockets. The annular member has an inner diameter large enough to enable the insertion of the holding member, and a leading end surface abuts on the driving-side sprocket in a rotatable state. COPYRIGHT: (C)2009,JPO&INPIT
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