GB436449A - Improvements in and relating to brake apparatus for railway and like vehicles - Google Patents

Abstract

436,449. Vacuum brake systems. LIVSEY, D. M., 47, Victoria Street, Westminster.-(Waylen, D. C.; 332, Avenue Paul Doumer, Rueil-Malmaison, France) April 5, 1934, No. 10382. [Class 103 (i)] In electrically - controlled vacuum - brake apparatus, two electromagnetically -operated valves 6, 9 are provided, one, which is normally open, for cutting - off communication between the brake cylinder 3 and train-pipe 1 when its circuit is completed, and the other, which is normally closed and which opens against atmospheric pressure, for putting the brake cylinder into communication with the atmosphere to apply the brakes when its circuit is completed. The apparatus as shown also includes a reserve vacuum chamber 11 controlled by a normallyopen, electromagnetically operated, reducing valve 12, and a normally - closed electromagnetically-operated equalizing valve 16 connected by a pipe 15 to the upper side of the brake piston 4. The circuits of the solenoids 7, 10, 13, 17 for the valves 6, 9, 12, 16 are controlled by the driver's handle 18. In operation, to apply the brakes on movement of the handle 18 to (a) the first brake application position A the valve 6 is closed cutting - off the trainpipe from the cylinder 3 and chamber 11 ; (b) position B the valve 12 is closed cutting-off the chamber 11 from the brake cylinder; (c) position C valve 9 is opened and atmospheric air flows beneath the piston 4 to apply the brakes. An apertured auxiliary air-reservoir may be fitted to valve 9 so that a measured quantity of air is admitted each time the valve is opened. When the brakes are applied to the desired extent, the handle 18 is moved back to position B, the valve 9 closing under its own weight. To effect partial release of the brakes the handle 18 is moved between the positions A, B opening the valve 12 and connecting the chamber 11 with the underside of piston 4, complete release being effected on further movement of the handle to normal position, opening the valve 6 and connecting the train-pipe with the cylinder 3 and chamber 11. To apply the brakes independently of the electrical system, the handle 18 may be moved to a fourth position (not shown), in which air enters the train-pipe through the driver's valve, all the electrical circuits being open. Movement of the handle to the first release position (not shown), on the other side of the normal position admits steam to the usual small ejector which maintains the brake vacuum against leakage. In the second release position (not shown), of the handle, the brake is blown off in the usual way. For a quick release the handle is moved to a third release position D opening the equalizing valve 16 so that the pressures on either side of the piston are equalized. The circuit - controlling means operated by the handle 18 comprises a commutator 36, Fig. 4, mounted on a shaft 34 rotatable by the handle 18, and co-operating contacts 37-40 for the four circuits shown in Fig. 3. A spring-loaded stop 44 on the shaft co-operates with recesses in the casing 30 corresponding to the various positions referred to.