Extended range hydraulic transmission

Claim 1

AN EXTENDED RANGE HYDRAULIC TRANSMISSION COMPRISING INPUT MEANS, HYDRAULIC TRANSMISSION MEANS INCLUDING A PAIR OF SEPARATE HYDRAULIC ELEMENTS, MEANS PROVIDING HYDRAULIC COMMUNICATION BETWEEN SAID ELEMENTS, ONE OF SAID HYDRAULIC ELEMENTS BEING PERMANENTLY DRIVINGLY CONNECTED WITH SAID INPUT MEANS, OUTPUT PLANETARY GEARING INCLUDING A PLURALITY OF MEMBERS, THE OTHER OF SAID HYDRAULIC ELEMENTS BEING PERMANENTLY DRIVINGLY CONNECTED WITH ONE OF THE MEMBERS OF SAID OUTPUT PLANETARY GEARING, OUTPUT MEANS, ANOTHER MEMBER OF SAID OUTPUT PLANETARY GEARING BEING PERMANENTLY DRIVINGLY CONNECTED WITH SAID OUTPUT MEANS, MEANS PROVIDING A DRIVING CONNECTION BETWEEN SAID INPUT MEANS AND A THIRD MEMBER OF SAID OUTPUT PLANETARY GEARING, SAID LAST-MENTIONED DRIVING CONNECTION INCLUDING SELECTIVELY ENGAGEABLE AND DISENGAGEABLE MEANS FOR CONNECTING OR DISCONNECTING SAID THIRD MEMBER FROM SAID INPUT MEANS, FIXED MEANS, SELECTIVELY ENGAGEABLE MEANS FOR CONNECTING OR DISCONNECTING SAID THIRD MEMBER WITH SAID FIXED MEANS FOR HOLDING SAID THIRD MEMBER AGAINST MOVEMENT, SAID HYDRAULIC ELEMENTS EACH INCLUDING DRUM MEANS HAVING A PLURALITY OF PISTONS RECIPROCABLY MOUNTED THEREWITHIN, SWASH PLATE MEANS FOR CONTROLLING THE STROKE OF SAID PISTONS, AND A CONTROL SYSTEM OPERATIVELY CONNECTED WITH EACH OF SAID SELECTIVELY ENGAGEABLE AND DISENGAGEABLE MEANS FOR OPERATING SAID SELECTIVELY ENGAGEABLE AND DISENGAGEABLE MEANS, SAID CONTROL SYSTEM ALSO BEING OPERATIVELY CONNECTED WITH SAID SWASH PLATE MEANS FOR CONTROLLING THE MOVEMENT THEREOF, SAID CONTROL SYSTEM INCLUDING COMPENSATING MEANS WHICH OPERATES THE SWASH PLATE MEANS TO ADJUST THE DRIVE RATIO THROUGH SAID HYDRAULIC ELEMENTS IN A DIRECTION OPPOSITE TO THE DRIVE RATIO CHANGE EFFECTED BY SAID SELECTIVELY ENGAGEABLE AND DISENGAGEABLE MEANS IN SUCH A MANNER AS TO MAINTAIN A CONSTANT OVER-ALL DRIVE RATIO.