| 摘要 |
PROBLEM TO BE SOLVED: To use a lift in an atmosphere where rain water comes down or flammable gas is generated by synchronously control two hydraulic actuators with a high degree of accuracy with the use of a small-sized and inexpensive arrangement. SOLUTION: A hydraulic pump 3 defines therein a hydraulic chamber 4A connected to a hydraulic cylinder 2A, a hydraulic chamber 4B connected to a hydraulic cylinder 2B and a piston chamber 5 connected to an air compressor 7 and incorporating a piston 8 which is provided thereto with two rods 9A, 9B. The piston is reciprocated by compressed air so that the rods are alternately moved back and forth. A pneumatic circuit is composed of a directional control valve 11 for changing over the moving direction of the piston, and limits valves 12A, 12B for operating the directional control valve at each stroke end of the piston. A hydraulic circuit is composed of manual selector valves 16A, 16B for changing over the operating direction of the hydraulic cylinders, and relief valves 17A, 17B for setting relief pressures for the hydraulic cylinders.
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