The device has a transport part (2) slidably mounted with respect to an index part (1), and a threaded rod (3) provided with ends (31, 32). A stop (34) is integrated with one of the ends of the rod. A nut (4) is mounted on the rod. The stop and the nut are arranged on both sides of a bracket i.e. recess (14). The stop cooperates with the bracket for blocking the rotation of the rod with respect to the index part. The nut is free to rotate with respect to the index part. A drive unit connects a control shaft (6) with the nut, and is constituted of a tubular cover (71) and a washer (72).
