Abstract: A locking device includes a first lock body which has a front end with a first clamp member projecting frontwardly, a rear end opposite to the front end and a blind bore extending longitudinally from the front to the rear end. An elongated rod with a plurality of annular grooves formed along the length is retractably received in the blind bore. A second lock body has a front end with a second clamp member projecting frontwardly and a rear end opposite to the front end. The rear end of the second lock body is pivoted to the rear end of the first lock body between a first position where the second clamp is distal from the first clamp and a second position where the second clamp cooperates with the first clamp to define an enclosed clamp. A key-operated cylinder lock including a plug member therein retains the elongated rod at a predetermined position and disengages the second lock body from the first lock body at the second position.