| 摘要 |
PURPOSE: An operation system of a cylinder in a truck type hydraulic crane is provided to make a 2 staged-boom and a 3 staged-boom respectively and simultaneously. CONSTITUTION: In stretching a 2 stage boom and a 3 staged boom simultaneously, boom stretching operation is performed when the booms are contracted completely. The pump hydraulic oil transmitted from a main control valve(7) is flowed into a flux divider(5) by passing a hydro-valve(6). The hydraulic oil divided half by the flux divider is flowed into a 2 staged cylinder and a 3 staged cylinder by passing a contractive control valve(8) and stretches respective cylinder. Herein, a solenoid valve(8c) for operating a 2 staged logic valve and a solenoid valve(8d) for operating a 3 staged logic valve are not applied with electricity. Thus, the booms are stretched in the same length. For stretching only the 2 staged boom, the solenoid valve(8d) for operating a 3 staged logic valve is applied with electricity. A logic valve(8b) for adjusting a 3 staged cylinder is opened. The flux supplied to the 3 staged boom line via the flux divider is bypassed. Thereby, only the 2 staged boom is stretched.
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