Booster-type servomotor for brake systems

Claim 1

A PRESSURE FLUID OPERATED SERVOMOTOR INCLUDING A CASING IN WHICH A MOVABLE POWER ASSEMBLY IS ACTUATABLE BY A PRESSURE DIFFERENTIAL ON OPPOSITE SIDES THEREOF, SAID POWER ASSEMBLY DIVIDING THE INTERIOR OF SAID CASING INTO A CONSTANT PRESSURE CHAMBER AND A VARIABLE PRESSURE CHAMBER, A SOURCE OF PRESSURE DIFFERENT FROM ATMOSPHERE, AND AN OPERATOR-OPERATED MEMBER HAVING A NORMALLY RELEASED POSITION, THE IMPROVEMENT WHICH COMPRISES: AN ELEMENT MOVABLE TO PERFORM WORK UNDER INFLUENCE IN PART OF POWER-ACTUATION, MOVEMENT OF SAID ELEMENT BEING OPPOSED BY A NORMALLY PRELOADED SPRING; A CONTROL VALVE HAVING AT LEAST TWO PRINCIPAL COOPERATING ELEMENTS ADAPTED TO HAVE OPERATIVE FOLLOW-UP ASSOCIATION WITH SAID POWER ASSEMBLY TO CONTROL THE SAME, SAID VALVE ELEMENTS BEING RELATIVELY DISPLACEABLE FROM NORMAL "OFF" POSITION WHEREIN SAID SERVOMOTOR CHAMBERS ARE INTERCONNECTED TO BALANCE PRESSURES THEREIN TO INACTIVATE SAID SERVOMOTOR, TO OPERATING "ON" POSITION WHEREIN SAID SERVOMOTOR CHAMBERS ARE ISOLATED TO ENABLE ESTABLISHMENT OF DIFFERENTIAL PRESSURES THEREIN TO ACTIVATE SAID SERVOMOTOR AS A FUNCTION OF THE REACTION FROM SAID WORK-PERFORMING ELEMENT; A FLUID CONNECTION BETWEEN SAID CONTROL VALVE AND SAID VARIABLE PRESSURE CHAMBER VIA SAID POWER ASSEMBLY; SPRING MEANS INCLUDING A NORMALLY PRELOADED SPRING OPERABLY DISPOSED IN SAID VARIABLE PRESSURE CHAMBER TO REACT BETWEEN SAID CASING AND ONE OF SAID VALVE ELEMENTS ACTUATED DIRECTLY BY SAID OPERATOR MEMBER, SAID LAST-MEMTIONED SPRING BEING CHARACTERIZED BY PROGRESSIVELY INCREASING REACTION ON SAID OPERATOR MEMBER IN ACCORDANCE WITH THE DISTANCE SAID POWER ASSEMBLY MOVES; OPERATING MECHANISM MOUNTED IN PART ON SAID POWER ASSEMBLY TO INTERCONNECT SAID SPRING MEANS AND ONE VALVE ELEMENT FOR MOVEMENT AS A UNIT; AND NORMALLY SPACED ENGAGEABLE PORTIONS DISPOSED RESPECTIVELY ON SAID ONE VALVE ELEMENT AND SAID POWER ASSEMBLY TO DEFINE THE SAID RELATIVE DISPLACEMENT OF SAID VALVE ELEMENTS, SAID PORTIONS BEING ENGAGEABLE TO EFFECT "STRAIGHT-THROUGH" OPERATION OF SAID POWER ASSEMBLY AND WORK-PERFORMING ELEMENT FROM SAID OPERATOR MEMBER IN COOPERATION WITH OR INDEPENDENTLY OF AN ENERGIZED STATUS OF SAID SERVOMOTOR.