Rotary clamp

A rotary clamp comprising:

• a piston (4) which is inserted in a housing (1) so that the piston (4) is movable in an axial direction;
• a housing hole (5) which is provided in the axial direction in the piston (4);
• an output rod (6) which is inserted in the housing hole (5) so that the output rod (6) is movable in the axial direction;
• a biasing means (9) which is disposed between the piston (4) and the output rod (6) and which biases the piston (4) and the output rod (6) so that the piston (4) and the output rod (6) are separated from each other;
• an operation chamber (15) which is provided on a base end side of the piston (4) and to/from which a pressurized fluid is supplied and discharged;
• a lock spring (16) which is provided on a top end side of the piston (4) in the housing (1) so that the lock spring (16) biases the piston (4) toward the base end side in the axial direction;
• a converting mechanism (22) which converts axial movement of the piston (4) into rotary movement of the output rod (6);
• a guide groove (28) which is provided in a circumferential direction on one of an inner circumferential wall of the housing hole (5) and an outer circumferential wall of the output rod (6) and which has a stopping part (29) provided at an end part, in the circumferential direction, of the guide groove (28);
• and
• an engaging member (31) which is provided on the other one of the inner circumferential wall of the housing hole (5) and the outer circumferential wall of the output rod (6) and which is inserted in the guide groove (28) and is caused to face the stopping part (29) at a given distance in the circumferential direction from the stopping part (29) so that the engaging member (31) can be in contact with the stopping part (29).