tongs 45 the sprung gripper 37 is of narrower design than the spacing of the hooks 52 of the locking arms 47 48 so that the latter can enter and leave the locking range of the tongs 49 without hindrance the entry of the rigid gripper 38 on the upper side of the locking arms 47 48 on the hook 50 52 is also made possible by bevels 53 54 made thereon as a result of the contact with the rigid gripper 38 the locking arms 47 48 are forced apart by means of the bevels 53 54 counter to a spring force until the rigid gripper 38 dips underneath the hook 52 into the locking range of the tongs 49 in a third exemplary embodiment according to fig6 7 the gripper shaft 39 has a toothed segment 56 which is in engagement with a rack 57 the rack 57 is mounted such that it can be displaced in the circumferential direction of the turner drum 32 counter to a compression spring 58 a wedge bar 59 mounted such that it can be displaced in the axial direction acts on the rack 57 and is used to fix the rack 57 and thus also to fix the gripper shaft 39 in engagement with.