Abstract: A load-responsive pressure reducing valve assembly for hydraulic brake systems to be interposed between a brake master cylinder and the rear wheel brake cylinders of a wheeled vehicle. The valve assembly includes a fluid pressure proportioning valve which restricts the flow of fluid from the master cylinder to the brake slave cylinders during a predetermined range of increasing fluid pressure supplied therefrom to the brake slave cylinders. The valve assembly also includes a deceleration sensing valve having a spherical inertia-responsive member that is responsive to a predetermined rate of vehicle deceleration to travel a predetermined distance up an incline to close off the supply of hydraulic fluid to a control chamber wherein the fluid pressure acts on a portion of the aforesaid proportioning valve, thus setting the reduction starting pressure of the fluid pressure proportioning valve.

Abstract: A load responsive pressure modulating valve device for use in a brake system of a vehicle is so constructed that the starting pressure for the pressure modulating operation is controlled by a specific valve operated by a partial pressure of the input hydraulic brake pressure. The device is capable of distributing the hydraulic brake pressure corresponding to a transient weight transfer from rear wheels of the vehicle to front ones caused by the braking operation, to the front and rear brakes by varying the starting pressure in response to load and deceleration of the vehicle.