Patent ID: 8292280

Claim:
An operation detecting device of a clamp comprising: a clamp rod ( 5 ) axially movably inserted into a housing ( 3 ); a detection hole ( 58 ) formed in one end wall ( 3 b ) of the housing ( 3 ) substantially concentrically with an axis of the clamp rod ( 5 ); an inlet hole ( 71 , 72 ) for supplying pressurized fluid opened in a peripheral surface of the detection hole ( 58 ); a detection member ( 62 ) axially movably fitted into the detection hole ( 58 ), the detection member ( 62 ) being movable laterally relative to the clamp rod ( 5 ), and having a closing surface ( 68 ) which laterally closes an opening portion ( 71 a , 72 a ) of the inlet hole ( 71 , 72 ) upon lateral movement of the detection member and a communication portion ( 69 ) through which the opening portion ( 71 a , 72 a ) is communicatively connected to outside air; and an operation portion ( 5 a ) provided at one end portion of the clamp rod ( 5 ), the operation portion ( 5 a ) being connected to the detection member ( 62 ), and an elastic member ( 91 ) arranged to laterally urge the detection member and closing surface laterally relative to the clamp rod ( 5 ) toward the opening portion ( 71 a , 72 a ).