AIR SERVO ACTUATOR AND MATERIAL TESTER

PROBLEM TO BE SOLVED: To provide an air actuator for eliminating an abnormal operation of a piston, surely and immediately stopping a test piece W and preventing the test piece W from being damaged even if an air supply is suddenly stopped so as to urgently stop the air actuator when the air actuator is used as an actuator of a load mechanism in a material tester. SOLUTION: The air actuator is provided with an shut-off valve 24 for shutting off the air supply to a servo valve by inputting an instruction signal, a communication valve 25 for communicating pressure chambers 21e, 21f on both sides of the piston 21b of an air cylinder 21, and a displacement regulating mechanism 26 for regulating a displacement of the piston 21b. When an urgent stop is required, the air supply to the air cylinder 21 is shut off by supplying the instruction signal, the air cylinder 21 is deactivated by communicating the pressure chambers 21e, 21f, the displacement of the piston 21b is regulated by the displacement regulating mechanism 26, and the piston 21b is immediately stopped. COPYRIGHT: (C)2007,JPO&INPIT