IN THIS DEVICE COMPRISING A PNEUMATIC CYLINDER 3 PNEUMATIC CYLINDER 3 AND PISTON 18 WITH A PISTON ROD 9, AND COMPRISING A MECHANISM 15 MADE TO BLOCK THE PISTON ROD, THE PISTON ROD INCLUDES A CARTER 6, 16, 32 TO NEIGHBORHOOD OF THE SAID CYLINDER AND IN WHICH EXTENDS THE PISTON ROD, A ...