Bumper construction for tow mast floor trucks

Claim 1

IN A FLOOR TRUCK TOW LINE SYSTEM WHEREIN WHEELED FLOOR TRUCKS EACH HAVING AN UPWARDLY EXTENDING TOW MAST ARE DRIVEN BY PUSHER MEMBERS OF AN OVERHEAD TOW LINE AND WHEREIN A DRIVEN FLOOR TRUCK IS EMPLOYED TO PUSH ONE OR MORE PRECEDING NON-DRIVEN FLOOR TRUCKS ONTO A SPUR LINE, MEANS FOR INCREASING THE DRIVING FORCE TRANSMISSABLE FROM THE TOW LINE THROUGH A DRIVEN FLOOR TRUCK COMPRISING A BUMPER MEMBER SECURED TO THE FRONT OF THE DRIVEN TRUCK AND PROJECTING FORWARDLY OF THE BASE OF THE TOW MAST THEREOF, A BUMPER SURFACE ON THE REAR OF A NON-DRIVEN TRUCK FOR PUSHING ENGAGEMENT BY THE BUMPER MEMBER OF THE DRIVEN TRUCK, AND A LEDGE MEMBER RIGIDLY CARRIED BY THE NON-DRIVEN TRUCK AND PROJECTING REARWARDLY OF AND BELOW THE BUMPER SURFACE THEREOF AND SLIGHTLY BELOW THE LEVEL OF THE BUMPER MEMBER OF THE DRIVEN TRUCK WHEREBY, UPON PUSHING ENGAGEMENT BETWEEN THE DRIVEN TRUCK AND A PRECEDING NON-DRIVEN TRUCK, ANY REARING UP MOVEMENT OF THE DRIVEN TRUCK WILL RESULT IN A PIVOTING OF THE DRIVEN TRUCK ABOUT ITS BUMPER MEMBER ON THE LEDGE MEMBER OF THE NON-DRIVEN TRUCK AND AN UPWARD MOVEMENT OF THE DRIVEN TRUCK TOW MAST.