Vehicle brake mechanism with pedal leverage changing means

Claim 1

A FLUID PRESSURE MOTOR MECHANISM COMPRISING A CASING, A PRESSURE RESPONSIVE UNIT THEREIN HAVING CHAMBERS AT OPPOSITE SIDES THEREOF, AN AXIALLY MOVABLE STRUCTURE COMPRISING A PAIR OF MEMBERS ONE OF WHICH FORMS WITH SAID PRESSURE RESPONSIVE UNIT ONE OF SAID CHAMBERS AND ENGAGES SAID PRESSURE RESPONSIVE UNIT, A VALVE MECHANISM CARRIED BY SAID ONE MEMBER AND CONNECTED TO A PRESSURE SOURCE AND OPERABLE FOR ESTABLISHING DIFFERENTIAL PRESSURES IN SAID CHAMBERS TO MOVE SAID PRESSURE RESPONSIVE UNIT, SAID MEMBERS BEING MOUNTED TO TELESCOPE, SAID AXIALLY MOVABLE STRUCTURE INCLUDING A CASING SURROUNDING THE OTHER OF SAID MEMBERS AND FORMING THEREWITH A PRESSURE CHAMBER IN FIXED COMMUNICATION WITH SAID SOURCE, A SPRING BETWEEN SAID MEMBERS BIASING SAID OTHER MEMBER AWAY FROM SAID ONE MEMBER AND NORMALLY HELD COMPRESSED BY PRESSURE IN SAID PRESSURE CHAMBER, A PEDAL HAVING A FIRST NORMAL POSITION IN WHICH IT ENGAGES AN ELEMENT OF SAID VALVE MECHANISM TO OPERATE THE LATTER AND FROM WHICH POSITION IT IS MOVABLE INDEPENDENTLY OF SAID OTHER MEMBER, AND CONTROL MEANS OPERABLE UPON A FAILURE OF PRESSURE IN SAID SOURCE AND CONSEQUENTLY IN SAID PRESSURE CHAMBER FOR RELEASING SAID SPRING TO MOVE SAID OTHER MEMBER TO RAISE SAID PEDAL TO A SECOND NORMAL POSITION