Patent GB-190327813-A (GB)
Title: Improvements in Automatic Fluid-pressure Brake Apparatus.
Filed: 1903-12-18
Granted: 1904-10-27
Abstract: 27,813. Westinghouse Brake Co., and Cloud, J. W. Dec. 18. Brakes, pneumatic-pressure. Consists in means for accelerating the initial partial application with or without means for subsequently accelerating the complete application of the brakes. Figs. 2 and 3 are sections at right-angles of the device which is attached at 4 to the train-pipe, and is preferably used with a plain triple valve which is joined to the train-pipe by a constricted connection. Figs. 5, 6, and 7 show the accelerator valve 9 in the release, partial application, and lap positions respectively. Under normal running conditions the piston 10, which actuates the valve 9, uncovers the groove 11 and maintains the reservoir 14 at train-pipe pressure, the small chamber 15 and large chamber 16 being opened to atmosphere by the registering of the valve with ports 21, 23, and the exhaust port 27 as shown in Fig. 5. If the train-pipe pressure fall for a partial action of the brakes, the pressure in the reservoir drives out the piston and sets the valve as in Fig. 6, so that the train-pipe discharges into the chamber 15 through the port 20, and the reservoir 14 discharges to atmosphere through ports 26, 25, and 27 until an equality of pressures brings the piston to the lap position shown in Fig. 7. Further reductions of train-pipe pressure cause the piston to oscillate between the positions of Figs. 6 and 7, the chamber 15 remaining charged, as the port 21 is always covered. There is thus no further accelerated action after the initial accelerated application. When the train-pipe pressure is greatly reduced for emergency use, either directly or after the initial application, the piston and valve overshoot the position of Fig. 6, driving in the plunger 30, and connecting the train-pipe with the large chamber 16 by means of the port 23 in addition to the chamber 15 via the ports 20, 21. At the same time the reservoir 14 is discharged to atmosphere by the registering of the valve with ports 25, 27, and the pressure falls until the spring 17 forces back the valve and closes the connection. between the chamber 16 and the train-pipe. The reservoir 14 may be alternatively exhausted to the chamber 16 or the atmosphere by a groove on the piston which only exhausts in the emergency position. A subsequent release brings the valve to the position of Fig. 5, and exhausts both chambers 15,16. According to the Provisional Specification, the chamber 15 may be open to atmosphere through a small hole from which the air slowly escapes after it is filled and closed to the train-pipe. The lost motion between the piston stem and valve shown in Fig. 2 may be varied in extent or dispensed with, and the train-pipe may be voided directly to atmosphere, the reservoir 16 and attendant parts being omitted. For use with quick-acting brakes, one chamber and exhaust port are used for the initial application only. Fig. 9 shows a form in which the accelerator valve is actuated by the triple-valve piston, train-pipe air passing through the passages 33, 35, groove 11, and triple - valve chamber 36 to the ordinary auxiliary reservoir 37. The port 20 of the chamber 15 (not shown) is connected by the valve 9 to the exhaust port 27, port 25 being omitted as the reduction of pressure, when the auxiliary reservoir discharges to the brake cylinder, is sufficient to cause the piston to return.