Load modulation and relay structure

Claim 1

A LOAD-MODULATION STRUCTURE FOR VEHICLE BRAKE SYSTEMS INCLUDING A HOUSING, A MOVABLE FULCRUM IN SAID HOUSING, A FULCRUM LEVER STRUCTURE POSITIONED IN SAID HOUSING FOR ENGAGEMENT WITH SAID FULCRUM, MEANS IN SAID HOUSING RESPONSIVE TO DELIVERY OF FLUID PRESSURE FOR MOVING SAID FULCRUM LEVER STRUCTURE, A FLUID PRESSURE INLET IN SAID HOUSING, A FLUID PRESSURE OUTLET IN SAID HOUSING FORMED AND ADAPTED FOR COMMUNICATION WITH THE BRAKES OF A VEHICLE, A VALVE BETWEEN SAID INLET AND SAID OUTLET, MEANS RESPONSIVE TO MOVEMENT OF SAID FULCRUM LEVER STRUCTURE FOR OPENING SAID VALVE, A LEVER ARM PIVOTALLY MOUNTED EXTERNALLY OF SAID HOUSING AND HAVING AN END PORTION PIVOTALLY CONNECTED WITH SAID FULCRUM, YEIDLING MEANS URGING SAID FULCRUM AND LEVER ARM IN ONE DIRECTION, AND A SENSING STRUCTURE SECURED TO SAID ARM AND SAID VEHICLE, SAID SENSING STRUCTURE INCLUDING A PAIR OF SEPARABLE ELEMENTS CONNECTED TO SAID VEHICLE FOR SEPARATION IN RESPONSE TO LIGHTENING OF SAID VEHICLE, SAID SENSING STRUCTURE INCLUDING A YIELDING MEANS FORMED AND POSITIONED TO URGE SAID SEPARABLE ELEMENTS TOGETHER, SAID LAST-NAMED YIELDING MEANS BEING PRELOADED AT ALL POSITIONS OF SAID SEPARABLE ELEMENTS, AT A FORCE GREATER THAN THAT OF SAID FIRST YIELDING MEANS AND THE FRICTION WITHIN SAID HOUSING.