| 摘要 |
PURPOSE:To prevent generation of vibration as well as provide possibility of eliminating turbulence of the magnetic field in a lens caused by a motor, by incorporating a construction which does not require to use any motor to drive a selector valve installed in order to connect the intake hole and exhaust hole selectively to a communication pipe, which shall communicate them to the cylinder. CONSTITUTION:In the initial state, a vane 14a is pressed to B position by a coil spring 15 of a selector valve 14, and a communication pipe 5 in communication with the cylinder 2 is connected with an intake hole 6a. When a compressor is put in service, a compressed gas flows through said communication pipe 5 and pipes 3a, 3b, and fills the cylinder 2 to depress pistons 1a, 1b. In this state, the pressure in a space M is higher than that on the exhaust side 6b, so that the pistons 1a, 1b are heaved, and the gas flows through the exhaust hole 6b to be exhausted to the compressor side. According to this arrangement, use of a motor is not required to drive the selector valve 14, so that vibration is scarcely produced as well as there is no magnetic field from motor, which serves prevention of turbulence of the magnetic field in the lens. |
