| 摘要 |
PROBLEM TO BE SOLVED: To provide only two lines as oil passages formed at a swivel joint for oil piping installed in a revolving frame of a concrete pump vehicle. SOLUTION: A slip ring device 46 is installed at the swivel joint 38 for oil piping installed at the revolving frame 3. Electric wiring is led to the upper part of the revolving frame 3 from the slip ring device 46 through the inside of a turning cylinder 16 of the swivel joint 38 for oil piping. Solenoid selector valves 27, 28, 29 for switching supply/discharge of pressure oil from a hydraulic pump 41 to boom derricking hydraulic cylinders 9, 10, 11 are installed on the revolving frame 3. A current is applied through the electric wiring to solenoids of the respective solenoid selector valves 27, 28, 29 on the revolving frame 3. Pipelines 43a, 44a for supply and discharge of pressure oil are thereby used as pressure oil piping leading to the solenoid selector valves 27, 28, 29 on the revolving frame 3, and two lines 39, 40 are used as the oil passages formed at the swivel joint 38 for oil piping. COPYRIGHT: (C)2006,JPO&NCIPI
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