| 摘要 |
PROBLEM TO BE SOLVED: To provide a material testing machine in which an accident damaging the hand is not generated, even if the hand is caught by mishandling of operation for gripping a test piece. SOLUTION: The material testing machine is constituted, in such a way that a selector valve 10 used to supply and discharge a liquid pressure to both cylindrical chambers FS, FP in a double-acting cylinder mechanism via a liquid pressure circuit PV, is installed, the output shaft of a cylinder 6 is advanced by operating the selector valve 10 and both edges 1K are brought close, so as to grip the test piece. An elastic body which urges the output shaft of the cylinder 6 in the direction of advancing the output shaft, without supplying the liquid pressure is installed at the cylinder mechanism, and a communication mechanism which makes both cylinder chambers FS, FP communicate with each other is installed at the selector valve 10. Consequently, the output shaft of the cylinder is advanced due to the elastic force of the elastic body, and both wedges 1K grip the testing piece. The test piece is not gripped by an oil pressure, it is gripped due to a gripping force at such a degree that the testing piece is not separated or will not fall, and the hand will not be damaged, even if the hand is squeezed.
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