Hydraulic system

Claim 1

IN COMBINATION A PUMP; A SUMP FROM WHICH SAID PUMP DRAWS FLUID; AT LEAST TWO REVERSIBLE MOTORS EACH HAVING TWO CONNECTIONS ALTERNATIVELY SERVING AS AN INLET AND AN OUTLET; A REVERSING VALVE HAVING A SUPPLY CONNECTION CONNECTED WITH THE PUMP, AN EXHAUST CONNECTION CONNECTED WITH THE SUMP AND TWO MOTOR PORTS, SAID VALVE HAVING AT LEAST TWO POSITIONS IN THE FIRST OF WHICH IT ESTABLISHES A FLOW PATH FROM THE SUPPLY CONNECTION TO ONE MOTOR PORT AND FLOW PATH FROM THE OTHER MOTOR PORT TO SAID EXHAUST CONNECTION AND IN THE SECOND OF WHICH THE FLOW PATHS ESTABLISHED BETWEEN THE MOTOR PORTS AND THE SUPPLY AND EXHAUST CONNECTIONS, IN THE FIRST POSITION, ARE REVERSED; A SELECTOR VALVE MEANS SHIFTABLE BETWEEN FIRST AND SECOND POSITIONS, IN WHICH RESPECTIVELY IT CONNECTS SAID MOTORS IN SERIES FLOW RELATION BETWEEN SAID MOTOR PORTS OR IN PARALLEL FLOW RELATION BETWEEN SAID MOTOR PORTS; A SINGE-ACTING EXPANSIBLE CHAMBER MOTOR CONNECTED TO SHIFT SAID SELECTOR VALVE MEANS FROM SAID FIRST TOWARD SECOND POSITION; YIELDING MEANS BIASING THE MOTOR AND THE SELECTOR VALVE MEANS TOWARD FIRST POSITION; A FLOW PASSAGE CONNECTING THE EXPANSIBLE MOTOR CHAMBER WITH SAID SUPPLY CONNECTION; AND A SUPPLY AND EXHAUST VALVE MEANS IN SAID FLOW PASSAGE YIELDINGLY BIASED TOWARD ITS EXHAUST POSITION AND SHIFTABLE, AGAINST SAID BIAS AND IN RESPONSE TO PRESSURE IN SAID FLOW PASSAGE, TO SUPPLY POSITION IN WHICH FLOW COMMUNICATION TO SAID MOTOR CHAMBER IS ESTABLISHED, WHEN SAID PRESSURE EXCEEDS A FIRST PREDETERMINED AMOUNT, OR TO EXHAUST POSITION IN WHICH THE PASSAGE IS BLOCKED AND THE MOTOR CHAMBER IS VENTED, WHEN PRESSURE IN SAID PASSAGE IS BELOW A SECOND LOWER PREDETERMINED AMOUNT, OR TO A LAP POSITION WHEN PRESSURE IN SAID PASSAGE IS INTERMEDIATE SAID PREDETERMINED AMOUNTS.