Abstract: A strut (6) of a circular plug projects upward from a main body (4) of a housing (3) and inserts into circular hole (9) of work (8). An opening (20) is formed laterally in a left portion of peripheral wall (18) of strut (6), a cam portion (28) projects leftward from a right portion of the peripheral wall (18). A positioning rod (22) inserts into insertion hole (14) in upper portion of housing (3) which is movable vertically and radially. A cam surface (32) is provided vertically on upper right portion of positioning rod (22), and pushing portion (33) is provided on upper left portion thereof. When a driving arrangement (D) drives positioning rod (22) downward for locking, cam portion (28) pushes the cam surface (32) leftward, and pushing portion (33) passes through opening (20) to press inner periphery of the circular hole (9) of work (8).

Abstract: A plurality of engagement members (20), inserted in a hole in an object to be fixed, which are capable of gripping an inner circumferential surface of the hole are provided, and a wedge face (32) of a clamping rod (15) is engaged on an inner circumference of the engagement member (20) from an upper side. An upper part of a piston rod (55) protruding upward from a piston body (54) of a piston (12) is coupled to a lower part of the clamping rod (15). The engagement member (20), the clamping rod (15), and the piston (12) are provided in a housing (2). An annular valve member (78) is provided between the housing (2) and the piston rod (55). When the piston (12) has moved to a lower-limit region in a lock direction, an actuating portion (89) of the piston rod (55) causes the valve member (78) via an actuated portion (99) of the valve member (78) to be opened downward.

Abstract: A plurality of engagement members (20), inserted in a hole in an object to be fixed, which are capable of gripping an inner circumferential surface of the hole are provided, and a wedge face (32) of a clamping rod (15) is engaged on an inner circumference of the engagement member (20) from an upper side. An upper part of a piston rod (55) protruding upward from a piston body (54) of a piston (12) is coupled to a lower part of the clamping rod (15). The engagement member (20), the clamping rod (15), and the piston (12) are provided in a housing (2). An annular valve member (78) is provided between the housing (2) and the piston rod (55). When the piston (12) has moved to a lower-limit region in a lock direction, an actuating portion (89) of the piston rod (55) causes the valve member (78) via an actuated portion (99) of the valve member (78) to be opened downward.

Abstract: A strut (6) of a circular plug projects upward from a main body (4) of a housing (3) and inserts into circular hole (9) of work (8). An opening (20) is formed laterally in a left portion of peripheral wall (18) of strut (6), a cam portion (28) projects leftward from a right portion of the peripheral wall (18). A positioning rod (22) inserts into insertion hole (14) in upper portion of housing (3) which is movable vertically and radially. A cam surface (32) is provided vertically on upper right portion of positioning rod (22), and pushing portion (33) is provided on upper left portion thereof. When a driving arrangement (D) drives positioning rod (22) downward for locking, cam portion (28) pushes the cam surface (32) leftward, and pushing portion (33) passes through opening (20) to press inner periphery of the circular hole (9) of work (8).