Hydraulic apparatus

Claim 1

A POWER TRANSMISSION COMPRISING A POSITIVE DISPLACEMENT PUMP, A POSITIVE DISPLACEMENT MOTOR, HYDRAULIC PASSAGE MEANS CONNECTING THE PUMP TO THE MOTOR, MOTOR SPEED ADJUSTMENT MEANS OPERABLE ON ONE OF THE PUMP AND THE MOTOR DISPLACEMENTS TO VARY MOTOR SPEED, A MECHANICAL GEARBOX, AN INPUT SHAFT FOR SAID GEARBOX DRIVEN BY THE SAID MOTOR, AN OUTPUT SHAFT FOR SAID GEARBOX, AT LEAST TWO SELECTABLE GEARS OF DIFFERING SPEED RATIOS ENGAGEABLE WITHIN SAID GEARBOX BETWEEN THE OUTPUT AND THE INPUT SHAFTS, A SELECTOR FOR THE GEARS IN THE GEARBOX, A SINGLE CONTROL OPERATIVELY CONNECTED BOTH TO THE MOTOR SPEED ADJUSTMENT MEANS AND TO THE SELECTOR, AND A GATE LOCATING SAID CONTROL FOR MOVEMENT IN A PREDETERMINED PATH HAVING A PAIR OF PARALLEL PORTIONS CORRESPONDING ONE TO LOW GEARBOX SPEED RATIO AND THE OTHER TO HIGH GEARBOX SPEED RATIO, MOVEMENT IN EITHER OF WHICH PORTIONS ADJUSTS MOTOR SPEED WITHOUT ADJUSTMENT OF THE GEARBOX SELECTOR, AND A TRANSVERSE CONNECTING PORTION BETWEEN THE PARALLEL PORTIONS HAVING AN INCLINATION THERETO, MOVEMENT THROUGH SAID TRANSVERSE PORTION SERVING TO MOVE THE SELECTOR TO CHANGE MECHANICAL GEAR AND TO MOVE THE MOTOR SPEED ADJUSTMENT MEANS TO ADJUST MOTOR SPEED INVERSELY IN PROPORTION TO THE PROPORTIONAL CHANGE OF GEAR SPEED RATIO, WHEREBY AFTER MOVEMENT OF THE CONTROL THROUGH THE SAID TRANSVERSE PORTION, THE SPEED OF THE OUTPUT SHAFT IS SUBSTANTIALLY THE SAME AS THE SPEED OF THE LOAD.