GB1142009A - Vehicle braking pressure control device - Google Patents

Abstract

1,142,009. Braking pressure control devices. DUNLOP CO. Ltd. 24 May, 1966 [8 June, 1965], No. 24105/65. Heading F2F. A braking pressure control device for controlling the distribution of braking pressure to the front and rear wheels of a vehicle comprises a valve housing 1 having an inlet 11 and an outlet 10 for connection to a fluid pressure source and the wheel brake operating mechanism of the vehicle respectively. A valve member 14 is housed in the inlet passage of the housing and is influenced by an inertia operated control mass 4 and an auxiliary control device. The mass 4 is surrounded by a cylinder 6 of a plastics material to act as a cushion between the wall of the valve housing and the mass and to damp movement of the mass. A resilient cushion 8 is also provided in the valve housing. On retardation of the vehicle the control mass 4 under the retardation forces and the force applied by the valve stem moves to allow the closure of the valve member 14 fluid pressure then being transmitted from the inlet to the outlet at a reduced rate through a by-pass incorporating a spring loaded piston 27. The auxiliary control device including a spring loaded plunger 19 acts on the valve member spring 18 such that, on the vehicle being loaded, a higher fluid pressure is required to provide an adequate deceleration, this higher fluid pressure depressing the spring loaded plunger 19 and thus reducing the biasing force on spring 18. A higher pressure fluid is thus allowed to flow through the outlet before the valve member 14 is allowed to close. In a modification (Fig. 2, not shown) the inertia control mass rocks about a projection formed at the lower end of the valve housing chamber and positioned about the stem of the valve member. Further, the mass may at its lower end be curved in two directions at right angles to each other and be mounted to rock on a pivoted plate, the auxiliary control device affecting the angle of tilt of the plate (Figs. 3, 4, not shown). Further, the mass may comprise a pendulum mounted below (Figs. 5, 6, 7, not shown) or above (Figs. 8, 9) the valve housing. In all cases the pivoting points of the pendulum are offset with respect to the axis of the pendulum arm such that fluid pressure acting on the arm tends to urge the pendulum arm away from the valve member closing position.