A clamping device including a clamp band (11, 110) of metal strip material (M) cut to a fixed length (L), said clamp band (11, 110) being wound in a circular ring for three-dimensionalization such that an inner overlap portion (11a, 110a) terminating in one roll-bent end and an outer overlap portion (11b, 110b) terminating in the other end overlap each other by a fixed amount (X), the bore diameter of said clamp band (11, 110) being artificially forcibly contracted, thereby fixing a part to be fixed (10), such as a fluid conveying hose, dustproof bellows, axial boot or the like made of plastic material, such as rubber or synthetic resin, on the connecting circumferential surface of a desired mating device (26), said clamping device being characterized in that:
- one cut end of the inner overlap portion (11a, 110a) alone is notched to form a nose (12, 120) of fixed width (W1) smaller than the fixed width (W) of the metal strip material (M),
- the inner overlap portion (11a, 110a) is formed with a prop key receiving hole (14, 140) and a fixed tooth receiving hole (15, 150), distributed in the order mentioned from the nose (12, 120) toward an intermediate portion (11c, 110c) where the clamp band (11, 110) does not overlap, and a first operating tool receiving hole (17, 170) is formed in said intermediate region (11c, 110c) adjacent said fixed tooth receiving hole (15, 150),
- the opening edge of said first operating tool receiving hole (17, 170) on the side adjacent said fixed tooth receiving hole (15, 150) is outwardly bulged to form a second convex channel wall (18, 180) for operating tool support,
- the opening edge of said fixed tooth receiving hole (15, 150) on the side adjacent the prop key receiving hole (14, 140) is outwardly bulged to form a first convex channel wall (16, 160), and a portion of the middle of said first convex channel wall (16, 160) forms a seizing tooth (16a, 160a) bulged toward said fixed tooth receiving hole (15, 150),
- the outer overlap portion (11b, 110b) is formed with a hole (19, 190) for receiving the first convex channel wall (16, 160), a second operating tool receiving hole (20, 200) juxtaposed with said first operating tool receiving hole (17, 170, and a hole (21, 210) for receiving the nose (12, 120),
- the opening edge of said first convex channel wall receiving hole (19, 190) adjacent the other cut end is oppositely or inwardly bulged to form a concave channel wall (22, 220) opposed to said first convex channel wall (16, 160), a portion of the middle of said concave channel wall (22, 220) being bulged inwardly toward said first convex channel wall receiving hole (19, 190) to form a fixed tooth (22b, 220b) adapted to be seized by said seizing tooth (16a, 160a),
- the opening edge of the first convex channel wall receiving hole (19, 190) on the side opposed to said fixed tooth (22b, 220b) is bent to form a prop key (23, 230) adapted to be received in the prop key receiving hole (14, 140) through the first convex channel wall receiving hole (19, 190,
- the opening edge of the second operating tool receiving hole (20, 200) on the other cut end side is outwardly bulged to form a third convex channel wall (24, 240) opposed to said second convex channel wall (18, 180) for operating tool support,
- the clamp band (11, 110) is formed with elastic humps (25, 250) outwardly bulged between said second operating tool receiving hole (20, 200) and said nose receiving hole (21, 210) or between said first convex channel wall receiving hole (19, 190) and said nose receiving hole (21, 210) for storing the spring force acting circumferentially of the clamp band (11, 110),
- the arrangement being such that the active teeth (42) of a close type operating tool (P) are respectively engaged with the second convex channel wall (18, 180) of the first operating tool receiving hole (17, 170) in said inner overlap portion (11a, 110a) and the third convex channel wall (24, 240) of the second operating tool receiving hole (20, 200) in said outer overlap portion (11b, 110b) and the operating tool (P) is manipulated to close its pair of active teeth (24) to forcibly deform the bore diameter of said clamp band (11, 110), whereupon the seizing tooth (16a, 160a) of the inner overlap portion (11a, 110a) and the fixed tooth (22b, 220b) of the outer overlap portion (11b, 110b) seize each other,
- and as soon as a force acts to cause disengagement between the fixed tooth (22b, 110b) and the seizing tooth (16a, 160a), the prop key (23, 230) of the outer overlap portion (11a, 110a) engages the opening edge of the prop key receiving hole (14, 140) in the inner overlap portion (11a, 110a).