Patent GB-563899-A (GB)
Title: Improvements relating to vehicle brakes
IPC: B60T8/18
Filed: 1942-09-23
Abstract: 563,899. Fluid-pressure brakes. BROWALL, B. H., and SVENSKA AKTIEBOLAGET BROMSREGULATOR. Sept. 23, 1942, No. 13406. [Class 103 (i)] In Westinghouse systems of the kind comprising two brake cylinders one of which is rendered active or inactive by means of a plug cock according to the load condition of the vehicle, the plug cock is replaced by a slidable valve member operable by a fluid-pressure servo-motor controlled automatically in accordance with the vehicle load or by hand. The system comprises brake cylinders C<1>, C<2> controlled by a triple valve that includes the part T<1> controlled by brake pipe pressure and the " quick-inshot " part T<2>. For the plug of the usual plug-cock by which the cylinder C<2> is rendered active or inactive, there is substituted a fixed member 1 within which is a slidable member 5 engaged at one end by the stem 6 of a valve 7 normally seated on the end of the member 1. The other end of the member 5 abuts on the stem 31 of a valve 26 adapted to seat at 32 on the member 1 and comprising also a plate 29 upon which rests a spring 30 within a piston 25. Radial passages 22, 13 in member 1 are arranged to be connected through passages 19, 17, 15 and an annular chamber 12 around the member 5 when a ball-valve 16 is lifted by the conical wall of the chamber 12, by movement of the member 5 to the right. Passage 13 is controlled by a non-return valve 14. Conduits L<1>, L<2> leading from chambers at the ends of the casing can be connected by a valve R operated automatically according to the vehicle load or by hand. In " light " load conditions the valve R is closed and in release, cylinder C<1> is connected to atmosphere by conduit o and passage g in the triple valve and cylinder C<2> is connected through bore 9 in member 5 to piston chamber 251 which is connected to atmosphere. In an application, cylinder C<1> is supplied from the auxiliary reservoir A through conduit a, chamber D<1> of the device T<2> and conduits y, o. When the cylinder pressure reaches a predetermined value, the piston D<1> is depressed and the cylinder C<1> is then supplied only through the restricted passage W. At this stage compressed air is also supplied through chamber E, conduit q and passage 11 to chamber 3 and presses the valve 7 firmly on its seat. In " load " conditions, however, the valve R being open, air from chamber 3 is supplied through conduits L<1>, L<2> to piston chamber 35 so that member 5 is moved to the right, unseating valve 7 and thus permitting air to flow from chamber 3 through passages 6, 10 and conduit m to cylinder C<2>. Movement of the member 5 also unseats the ball-valve 16, Fig. 3, thus opening an additional supply to the cylinders C<1>, C<2> from conduit a through passages 22, 13, and conduit o. In its right-hand position, the piston 25 is seated at 36 and it seats the valve 26 at 32 so that both the piston chamber 35 and the bore 9 are cut off from the piston chamber 25<1> and thus from the atmosphere. When the brake is released, chambers 3, 35 and cylinder C<2> are connected to atmosphere through conduit q thence at first through passages o, g and when the piston D<1> returns, through passages U, Z. The parts 25, 5, 7 thus return to the position shown.