Control device for cranes

Claim 1

IN A CRANE HAVING AN OVERHEAD BRIDGE ADAPTED TO TRAVEL TRANSVERSELY TO ITS LENGTH, A CARRIAGE MOUNTED ON SAID BRIDGE FOR TRAVEL LENGTHWISE THEREOF, A HOISTING MECHANISM MOUNTED ON SAID CARRIAGE, A FIRST ELECTRIC MOTOR MOUNTED ON SAID CARRIAGE FOR DRIVING SAID HOISTING MECHANISM TO RAISE AND LOWER A LOAD, A SECOND ELECTRIC MOTOR FOR MOVING SAID CARRIAGE BACK AND FORTH ALONG SAID BRIDGE, AND A THIRD ELECTRIC MOTOR FOR MOVING SAID BRIDGE TO THE LEFT AND RIGHT TRANVERSELY OF ITS LENGTH, A CONTROL SYSTEM COMPRISING FIRST AND SECOND CONTROL LEVERS, A PIVOTAL MOUNTING FOR SAID FIRST CONTROL LEVER TO MOUNT SAID FIRST LEVER FOR FORWARD AND BACKWARD MOVEMENT FROM A NEUTRAL POSITION IN A DIRECTION PARALLEL TO THE LENGTH OF SAID BRIDGE, FIRST SPRING MEANS BIASING SAID FIRST LEVER TO ITS NEUTRAL POSITION, A FIRST RHEOSTAT MEANS FOR ADDING VARIABLE AMOUNTS OF RESISTANCE TO THE CIRCUIT OF SAID FIRST MOTOR TO VARY THE SPEED OF ROTATION THEREOF, SAID FIRST LEVER BEING LINKED TO SAID FIRST RHEOSTAT MEANS TO DECREASE THE RESISTANCE ADDED BY SAID FIRST RHEOSTAT MEANS AS SAID FIRST LEVER IS MOVED AWAY FROM ITS NEUTRAL POSITION, FIRST ELECTRICAL REVERSING SWITCHES CONTROLLING ELECTRICAL POWER TO SAID FIRST MOTOR FOR CONTROLLING THE DIRECTION OF ROTATION THEREOF, SAID FIRST REVERSING SWITCHES HAVING FIRST AND SECOND POSITIONS EACH CORRESPONDING TO A DIRECTION OF ROTATION, SAID FIRST REVERSING SWITCHES BEING ACTUATED TO SAID FIRST POSITION BY MOVEMENT OF SAID FIRST CONTROL LEVER FROM ITS NEUTRAL POSITION IN SAID FORWARD DIRECTION AND TO SAID SECOND POSITION BY MOVEMENT OF SAID FIRST CONTROL LEVER FROM ITS NEUTRAL POSITION IN SAID BACKWARD DIRECTION, A UNIVERSAL MOUNTING FOR SAID SECOND CONTROL LEVER TO MOUNT SAID SECOND LEVER FOR MOVEMENT IN ANY PLANAR DIRECTION FROM A NEUTRAL POSITION, SECOND SPRING MEANS BIASING SAID SECOND LEVER TOWARDS ITS NEUTRAL POSITION, A SECOND RHEOSTAT MEANS FOR ADDING VARIABLE AMOUNTS OF RESISTANCE TO THE CIRCUIT OF