Abstract: A locking device for preventing movement of an elongated instrument includes a tubular base that has an outer surface and an inner surface. At least one lateral opening extends through the tubular base from the outer surface through the inner surface. At least one rocker arm is mounted to the base. Each of the rocker arms has a locking projection that extends radially inwardly aligned with one of the lateral openings of the base. An actuating member is rotatable relative to the base portion between first and second positions. In the first position the actuating member engages the rocker arm to urge the locking projection radially inward through the lateral opening and beyond the inner surface of the tubular base. Movement of the actuating member to the second position causes the locking projection to move radially outward through at least a portion of the lateral opening.