| 摘要 |
PURPOSE:To improve the easiness and the safety of operation by holding a running constructing machine or the like so that the switching control of the running direction is not performed however an upper turning body is turned while a running device runs. CONSTITUTION:The running constructing machine consists of an upper turning body 10 and a lower running device 12 and is provided with a position detector 14, detecting pieces 16 and 18 which detect positions to which the upper turning body 10 is displaced at 90 deg., and a ratchet relay 20 which is operated when contacts (a) and (b) are closed. Hydraulic motors 22 and 24 which control running of the lower running device 12 are connected to an oil pressure system through hydraulic pumps 26 and 28, direction switching valves 30 and 32, and a direction control valve 34. High pressure selecting valves 36-40 are connected to an oil pressure circuit, and a pressure switch 44 which is closed with a middle pressure and a pressure switch 46 which is opened with a high pressure are connected to an output line 42 of this circuit. A pressure switch 16 56 which is closed with a high pressure is arranged in a pilot oil pressure line 54 and is connected in series to said pressure switch 44 to energize a relay 48. |
