Ratio shift-point control system for a power transmission mechanism

Claim 1

IN A POWER TRANSMISSION MECHANISM ADAPTED TO DELIVER DRIVING TORQUE FROM AN ENGINE TO A DRIVEN MEMBER, A GEAR SYSTEM HAVING RELATIVELY MOVABLE ELEMENTS, ONE ELEMENT OF SAID GEAR SYSTEM BEING CONNECTED TO A DRIVEN MEMBER, MEANS FOR COUPLING POWER INPUT ELEMENTS OF SAID GEAR SYSTEM TO SAID ENGINE, REACTION BRAKE MEANS INCLUDING A FLUID PRESSURE OPERATED BRAKE SERVO FOR ANCHORING A FIRST REACTION ELEMENT OF SAID GEAR SYSTEM TO ACCOMMODATE DRIVING TORQUE REACTION AND CONDITION SAID MECHANISM FOR FIRST UNDERDRIVE SPEED RATIO OPERATION, CLUTCH MEANS INCLUDING A FLUID PRESSURE OPERATED SERVO FOR CONNECTING TOGETHER TWO ELEMENTS OF SAID GEAR SYSTEM TO CONDITION SAID MECHANISM FOR HIGH SPEED RATIO OPERATION, SAID BRAKE SERVO INCLUDING A PRESSURE MOVABLE BRAKE APPLYING MEMBER DEFINING IN PART BRAKE APPLY AND RELEASE PRESSURE CHAMBERS ON OPPOSED SIDES THEREOF, A FLUID PRESSURE SOURCE, CONDUIT STRUCTURE CONNECTING SAID SOURCE WITH SAID CLUTCH SERVO AND EACH PRESSURE CHAMBER OF SAID BRAKE SERVO WITH A COMMON PORTION THEREOF COMMUNICATING WITH SAID APPLY PRESSURE CHAMBER AND SAID CLUTCH SERVO, A SOURCE OF A PRESSURE SIGNAL THAT IS SENSITIVE TO CHANGES IN ENGINE TORQUE, SHIFT VALVE MEANS DISPOSED IN AND DEFINING IN PART SAID CONDUIT STRUCTURE FOR SELECTIVELY DISTRIBUTING PRESSURE TO SAID COMMON PORTION TO ESTABLISH SPEED RATIO CHANGES, DISTRIBUTOR VALVE MEANS COMMUNICATING WITH SAID COMMON PORTION AND RESPONSIVE TO A PRESSURE BUILD-UP THEREIN FOR CONNECTING SAID SERVO APPLY CHAMBER TO A LOW PRESSURE REGION OF SAID CONDUIT STRUCTURE DURING A SHIFT INTERVAL, AND A FLUID CONNECTION BETWEEN SAID PRESSURE SIGNAL SOURCE AND SAID DISTRIBUTOR VALVE MEANS THEREBY ESTABLISHING A PRESSURE SIGNAL FORCE THAT OPPOSES THE INFLUENCE ON SAID DISTRIBUTOR VALVE MEANS OF SAID PRESURE BUILD-UP, A SECOND FLUID PRESSURE OPERATED BRAKE MEANS FOR ANCHORING A SECOND REACTION ELEMENT TO OBTAIN OPERATION IN ANOTHER UNDERDRIVE RATIO, SECOND SHIFT VALVE MEANS IN COMMUNICATION WITH SAID FLUID PRESSURE SOURCE FOR CONTROLLING DISTRIBUTION OF PRESSURE TO SAID SECOND BRAKE MEANS, AN AUXILIARY VALVE AREA ON SAID DISTRIBUTOR VALVE MEANS, AND PASSAGE MEANS FOR CONNECTING HYDRAULICALLY SAID AUXILARY AREA AND SAID SECOND BRAKE MEANS WHEREBY THE INFLUENCE OF SAID SIGNAL FORCE ON SAID DISTRIBUTOR VALVE MEANS IS OPPOSED.