either in the position shown in fig2 connected to the locking element 55 or in order to achieve a modified holding force is placed in a bore 62 in the locking element 55 through this modified position i e a modified lever arm in relation to the rotation axis 56 and or by means a spring with different spring characteristics the locking force of the locking elements 55 can be adjusted a stop 61 is provided to ensure that the insertion bevels 57 are always aligned with the centering plates 54 the two locking elements 55 can be moved only so far towards each other by mens of this stop 61 and via spring 59 that they come into alignment with the centering plates 54 the switch 32 is furthermore installed on the bottom plate 51 pin 33 serves as an actuating element and extends into the space between the locking notches 58 as soon as a pipe 24 is present in the space between the locking notches 58 the pin 33 is pressed into the switch 32 and triggers a signal to the spinning mill machine 1 whereby the surrender of the can by the spinning mill machine 1 is made possible as soon as the pin 33 is in its rest position due to the absence of a pipe 24 the spinning mill machine 1 is informed by signal that the can transfer must be stopped the pipe 24 is held in its position in the space between the locking notches 58 which are pressed together with more or less force by the spring 59 this position is maintained for as long as the cans are being pushed on the conveying carriage 2 as soon as the conveying carriage.