Combined dynamic and fluid pressure brake system for railway vehicles

Claim 1

FOR USE IN A COMBINED ELECTRO-DYNAMIC AND FLUID PRESSURE BRAKE SYSTEM FOR A VEHICLE, A VALVE MECHANISM COMPRISING: (A) A CASING HAVING THEREIN A FIRST CHAMBER, (B) A LEVER PIVOTALLY MOUNTED ON SAID CASING, (C) A FLUID MOTOR SUBJECT TO THE PRESSURE ESTABLISHED IN SAID FIRST CHAMBER FOR EXERTING A FIRST MOMENT ON SAID LEVER TENDING TO ROCK IT IN ONE DIRECTION, (D) ELECTRO-RESPONSIVE MEANS CARRIED BY SAID CASING ENERGIZED ACCORDING TO THE DEGREE OF DYNAMIC BRAKING EFFECT AND EFFECTIVE ACCORDING TO THE DEGREE OF ENERGIZATION THEREOF TO EXERT A CORRESPONDING SECOND MOMENT ON SAID LEVER TENDING TO ROCK IT IN AN OPPOSITE DIRECTION TO THEREBY COUNTERBALANCE SAID FIRST MOMENT WHEN SAID FIRST AND SECOND MOMENTS ARE OF EQUAL MAGNITUDE, (E) SELF-LAPPING VALVE MEANS OPERATIVE BY THE ROCKING OF SAID LEVER IN SAID ONE DIRECTION OUT OF A PREDETERMINED POSITION IN WHICH IT IS POSITIONED BY SAID MOMENTS WHEN OF EQUAL MAGNITUDE IN RESPONSE TO A REDUCTION IN THE MAGNITUDE OF THE MOMENT EXERTED BY SAID ELECTRO-RESPONSIVE MEANS TO SUPPLY A CONTROL FLUID PRESSURE CORRESPONDING IN DEGREE TO THE UNABLANCE OF SAID MOMENTS, SAID SELF-LAPPING VALVE MEANS INCLUDING FLUID PRESSURE RESPONSIVE MEANS SUBJECT TO THE CONTROL FLUID PRESSURE ESTABLISHED BY SAID VALVE MEANS TO EXERT A COUNTER MOMENT ON SAID LEVER FOR RESTORING IT SUBSTANTIALLY TO ITS PREDETERMINED BALANCED POSITION.