Controlled differential drive

Claim 1

IN A PAPER MAKING MACHINE AND THE LIKE HAVING A ROTATING LINE SHAFT AND A SERIES OF DRIVEN SECTION SHAFTS EACH TO BE ROTATED AT A SPEED PROPORTIONAL TO LINE SHAFT SPEED, A VARIABLE DIFFERENTIAL DRIVE UNIT FOR DRIVING EACH DRIVEN SECTION SHAFT FROM THE LINE SHAFT, EACH DRIVE UNIT COMPRISING AN INPUT SHAFT, MEANS FOR COUPLING SAID INPUT SHAFT TO THE LINE SHAFT FOR DRIVING SAID INPUT SHAFT AT A SPEED DIRECTLY PROPORTIONAL TO LINE SHAFT SPEED, AN OUTPUT SHAFT CONSTITUTING THE DRIVEN SECTION SHAFT, AN EPICYCLIC GEAR TRAIN BETWEEN SAID INPUT AND OUTPUT SHAFTS INCORPORATING A RATIO-CONTROLLING ELEMENT THEREIN WHICH DETERMINES THE DIFFERENCE IN ROTATIVE SPEED BETWEEN SAID INPUT SHAFT AND SAID OUTPUT SHAFT, A HYDRAULIC SYSTEM FOR CONTROLLING THE RATIO OF ROTATION OF SAID OUTPUT SHAFT WITH RESPECT TO SAID CONTROLLING ELEMENT, AND AN ELECTRICAL CIRCUIT GOVERNING THE ACTION OF SAID HYDRAULIC SYSTEM FOR SETTABLY VARYING SAID RATIO BETWEEN DESIRED VALUES, SAID CIRCUIT BEING ACTUATED BY ROTATION OF SAID OUTPUT SHAFT AND SAID CONTROLLING ELEMENT.