Clamping apparatus

1. A clamping apparatus comprising:

a housing ( 1 );

a locking member ( 23 ) protruding toward a leading end side relative to the housing ( 1 ) and configured to be insertable into a hole (Wa) of a to-be-clamped object (W);

a clamp rod ( 7 ) including a wedge surface ( 24 ) configured to be engaged with the locking member ( 23 ) from the leading end side;

a driving means ( 13 ) configured to drive the clamp rod ( 7 ) toward a base end side for clamping action and to drive the clamp rod ( 7 ) toward the leading end side for unclamping action;

a support member ( 19 ) supporting a base end portion of the locking member ( 23 ) so that the locking member ( 23 ) is radially movable, the support member ( 19 ) being inserted in a leading-end-side portion of the housing ( 1 ) so as to be movable in an axial direction of the housing;

a resistance giving mechanism ( 34 ) configured to give resistance to axial movement of the support member ( 19 ) with respect to both directions toward the leading end side and toward the base end side; and

an engagement maintaining mechanism ( 26 ) which allows the wedge surface ( 24 ) of the clamp rod ( 7 ) to be engaged with the locking member ( 23 ) so as to be movable relative to each other, wherein

when the clamp rod ( 7 ) is driven toward the leading end side for unclamping action, the clamp rod ( 7 ) moves the locking member ( 23 ) toward the leading end side via the support member ( 19 ) after the locking member ( 23 ) moves radially inward.

2. The clamping apparatus according to claim 1 , wherein

the support member ( 19 ) includes a tubular portion ( 20 ) in which the clamp rod ( 7 ) is inserted so as to be movable in the axial direction, and wherein

the resistance giving mechanism ( 34 ) includes:

an annular groove ( 32 ) provided on an outer peripheral surface of the tubular portion ( 20 ); and

a ring-shaped elastic member ( 33 ) attached to the annular groove ( 32 ).

3. The clamping apparatus according to claim 1 , wherein

the support member ( 19 ) includes a tubular portion ( 20 ) in which the clamp rod ( 7 ) is inserted so as to be movable in the axial direction, and wherein

the resistance giving mechanism ( 34 ) includes:

a lateral hole ( 38 ) bored in a side wall of a leading-end-side portion of the housing ( 1 ); and

an engagement member ( 39 ) and a biasing means ( 40 ) which are attached in the lateral hole ( 38 ), the biasing means ( 40 ) being configured to bias the engagement member ( 39 ) toward the tubular portion ( 20 ).

4. The clamping apparatus according to claim 1 , wherein

the support member ( 19 ) includes a tubular portion ( 20 ) in which the clamp rod ( 7 ) is inserted so as to be movable in the axial direction, and wherein

the resistance giving mechanism ( 34 ) includes:

a wedge member ( 43 ) engaged from the base end side with an inclined surface ( 42 ) provided on an outer periphery of the tubular portion ( 20 ) and inclined relative to the axial direction, the wedge member ( 43 ) being attached between the inclined surface ( 42 ) and an inner peripheral surface of the housing ( 1 );

a biasing means ( 44 ) configured to bias the wedge member ( 43 ) toward the leading end side; and

a holding means ( 45 ) holding the biasing means ( 44 ) close to an outer peripheral surface of the tubular portion ( 20 ).

5. The clamping apparatus according to claim 1 , wherein

the engagement maintaining mechanism ( 26 ) includes:

a rod-side engagement groove ( 24 a ) or rod-side engagement portion provided on the wedge surface ( 24 ) of the clamp rod ( 7 ); and

a locking-member-side engagement portion ( 25 a ) provided on the locking member ( 23 ), the locking-member-side engagement portion ( 25 a ) being configured to engage with the rod-side engagement groove ( 24 a ) or a locking-member-side engagement groove.

6. The clamping apparatus according to claim 1 , further comprising

a relative movement restriction mechanism ( 31 ) configured to restrict radially outward movement of the locking member ( 23 ) relative to the clamp rod ( 7 ) within a predetermined range when the clamp rod ( 7 ) is driven toward the base end side for clamping action.

7. The clamping apparatus according to claim 6 , wherein

the relative movement restriction mechanism ( 31 ) is an annular protrusion ( 30 ) provided at a leading-end-side end portion of the housing ( 1 ) and protruding radially inward, and a hole in the annular protrusion ( 30 ) has a diameter equal to or smaller than a diameter of the hole (Wa) of the to-be-clamped object (W).

8. The clamping apparatus according to claim 1 , wherein

the support member ( 19 ) includes:

a tubular portion ( 20 ) in which the clamp rod ( 7 ) is inserted so as to be movable in the axial direction;

a peripheral wall portion ( 21 ) provided on the leading end side relative to the tubular portion ( 20 ), the peripheral wall portion ( 21 ) having a guide hole ( 21 a ) in which the locking member ( 23 ) is inserted so as to be radially movable; and

a tapered top wall portion ( 22 ) provided on the leading end side relative to the peripheral wall portion ( 21 ).

9. The clamping apparatus according to claim 1 , wherein

the housing ( 1 ) includes:

a lower housing ( 2 ); and

a tubular upper housing ( 5 ), which is connected to a top surface of the lower housing ( 2 ) so as to be radially movable, and in which the support member ( 19 ) is inserted so as to be movable in the axial direction, and wherein

the clamp rod ( 7 ) includes:

a rod main body ( 52 ); and

a rod leading end portion ( 54 ) connected to a leading end portion of the rod main body ( 52 ) via a pin ( 53 ) so as to be movable in a radial direction of the rod main body ( 52 ), the rod leading end portion ( 54 ) being provided with the wedge surface ( 24 ).

10. The clamping apparatus according to claim 1 , wherein

the housing ( 1 ) includes:

a lower housing ( 2 ); and

a tubular upper housing ( 5 ), which is fixed to a top surface of the lower housing ( 2 ), and in which the support member ( 19 ) is inserted so as to be movable in the axial direction and a radial direction, and wherein

the clamp rod ( 7 ) includes:

a rod main body ( 52 ); and

a rod leading end portion ( 54 ) connected to a leading end portion of the rod main body ( 52 ) via a pin ( 53 ) so as to be movable in a radial direction of the rod main body ( 52 ), the rod leading end portion ( 54 ) being provided with the wedge surface ( 24 ).

11. A clamping apparatus comprising:

a housing ( 1 );

a locking member ( 23 ) protruding toward a leading end side relative to the housing ( 1 ) and configured to be insertable into a hole (Wa) of a to-be-clamped object (W);

a clamp rod ( 7 ) including a wedge surface ( 24 ) configured to be engaged with the locking member ( 23 ) from the leading end side;

a driving means ( 13 ) configured to drive the clamp rod ( 7 ) toward a base end side for clamping action and to drive the clamp rod ( 7 ) toward the leading end side for unclamping action;

a support member ( 19 ) supporting a base end portion of the locking member ( 23 ) so that the locking member ( 23 ) is radially movable, the support member ( 19 ) being inserted in a leading-end-side portion of the housing ( 1 ) so as to be movable in an axial direction of the housing;

an engagement maintaining mechanism ( 26 ) which allows the wedge surface ( 24 ) of the clamp rod ( 7 ) to be engaged with the locking member ( 23 ) so as to be movable relative to each other; and

a relative movement restriction mechanism ( 31 ) configured to restrict radially outward movement of the locking member ( 23 ) relative to the clamp rod ( 7 ) within a predetermined range when the clamp rod ( 7 ) is driven toward the base end side for clamping action, wherein

the relative movement restriction mechanism ( 31 ) is an annular protrusion ( 30 ) provided at a leading-end-side end portion of the housing ( 1 ) and protruding radially inward, and a hole in the annular protrusion ( 30 ) has a diameter equal to or smaller than a diameter of the hole (Wa) of the to-be-clamped object (W).