Platen-leveling control system for hydraulically-actuated brake presses

Claim 1

IN A HYDRAULICALLY OPERATED PRESS WHICH INCLUDES RELATIVELY STATIONARY, NON-DEFLECTABLE FRAME COMPONENTS, A BED, A MOVABLE PRESS PLATEN, A PAIR OF DOUBLE-ACTING HYDRAULIC MOTORS CONNECTED IN RELATIVELY SPACED APART RELATION WITH THE PRESS PLATEN AND OPERABLE IN RESPONSE TO PRESSURE FLUID SUPPLIED THERETO TO RECIPROCATE THE PRESS PLATEN TOWARD AND AWAY FROM THE BED OF THE PRESS, PUMP MEANS FOR SUPPLYING PRESSURE FLUID TO SAID HYDRAULIC MOTORS, AND A REVERSING VALVE HAVING CONNECTIONS WITH SAID PUMP MEANS AND EACH OF SAID MOTORS AND OPERABLE SELECTIVELY TO REVERSE THE DIRECTION OF MOVEMENT OF SAID MOTORS; A CONTROL FOR MAINTAINING THE PLATEN IN PRESELECTED ANGULAR RELATION TO THE BED OF THE PRESS DURING RECIPROCATING MOVEMENT OF THE PLATEN, SAID CONTROL COMPRISING A FIRST VALVE HAVING SEPARATE CONNECTIONS WITH EACH OF SAID HYDRAULIC MOTORS AND WITH SAID REVERSING VALVE AND HAVING A MOVABLE VALVE MEMBER OPERABLE TO INCREASE THE VOLUME OF FLUID PASSING TO AND FROM ONE OF SAID MOTORS WHILE PROPORTIONATELY DECREASING THE VOLUME OF FLUID PASSING TO AND FROM THE OTHER OF SAID MOTORS; MECHANICAL OPERATOR MEANS SUPPORTED BY NON-DEFLECTABLE FRAME COMPONENTS OF SAID PRESS AND HAVING CONNECTIONS WITH THE MOVABLE VALVE MEMBER OF SAID FIRST VALVE AND WITH SAID PLATEN, SAID OPERATOR MEANS BEING MOVABLE IN RESPONSE TO A DEVIATION IN ANGULAR RELATIONSHIP BETWEEN THE PLATEN