Differentially acting for protection valve reaches druckfluidbetaetigte

摘要

1365339 Brake valves CLAYTON DEWANDRE CO Ltd 20 Sept 1972 [14 Oct 1971] 47857/71 Heading F2F A differential protection valve for a vehicle has an inlet 2 connected to the service braking line, a second inlet 3 connected to a secondary, emergency or parking line and outlets 5 connected to spring brake actuators the valve being such that if the service brakes are applied with the secondary line exhausted and the spring brake actuators applied the service line pressure displaces a sleeve 10 and valve head 7a until the latter engages a seat 11 thereby interrupting the path from inlet 3 to outlets 5. Increased service pressure above a predetermined value effects continued movement of sleeve 10 causing a seal 8 on a flange 9 to move away from a valve head 7 thereby connecting inlet 2 to the spring brake actuators to decrease the effective load thereof and prevent overloading of the brakes and linkage. If the secondary line is exhausted while the service braking is operative at a pressure in excess of the predetermined value, valve head 7a closes against seat 11 to prevent the secondary line application until the service braking is released thereby preventing vehicle "roll-back".