Patent GB-188002-A (GB)
Title: Improvements in or relating to pneumatic brakes
IPC: B60T13/36
Filed: 1921-04-25
Abstract: 188,002. Drolshammer, I. April 25, 1921. Fluid-pressure. - In brakes of the kind described in Specification 164,041, local venting of the train-pipe is effected by the brake cylinder supply valve member instead of by the piston member which is subject to the train-pipe pressure, so that venting is effected at each reduction in train-pipe pressure. Manually actuated cocks for regulating the supply of air to the brake cylinder and the venting of the train-pipe and for releasing the brakes and a modified stop device for limiting the brake cylinder pressure on a vehicle are described. As shown in Fig. 1, the valve member s is provided with a chamber R which is normally open to an exhaust port p. The brake cylinder connected at g is, in the release position shown, connected to the exhaust port h. The train-pipe is connected at T and when the pressure therein is reduced to effect an application of the brakes. the piston K moves downwards under the action of the spring f<2> and through the spring f<1> moves the valve s to uncover the auxiliary reservoir port e to supply the brake cylinder. The exhaust port p of the chamber R is also closed and a passage o uncovered to allow the train-pipe to vent into this chamber. When the brake cylinder pressure acting through the passage o<1> on the piston a<3> has risen sufficiently the valve s is returned thereby to close the supply port e and to re-open the chamber R to the exhaust port p. If a further reduction in train-pipe pressure is effected the train-pipe is again vented to the chamber R. In the valve shown in Fig. 3 the train-pipe is conr.ected through a cock H<1> (1) to the chamber S beneath the piston K by passage 29, (2) to ports X<1>, X<2> through ports 27. 28 and passage 0, and (3) past a non-return valve v<1> to a port k. The. train-pipe is thus vented to the brake cylinder by the valve s both through the port k and the ports X<1>, X<2>. With a gradual reduction in train-pipe pressure only the small port X<1> is uncovered, with a quick reduction both the ports X<1>, X<2> ara uncovered. The ports X<1>, X<2> may instead vent the train-pipe to the atmosphere. The cock H<1> may be turned to cut off (1) the port 28 (2) the ports 27 and 28 or (3) the passage to the port 29 as well as the ports 27, 28. A second cock may be provided adapted to regulate or cut off the passage E from the auxiliary reservoir and also to connect the passage g from the brake cylinder to atmosphere. The stop device for limiting the brake pressure comprises two rack sleeves m, 11 free to slide with respect to each other and the rod d of the piston K. The sleeves are engaged by pinions B<1>, B<2>. The sleeve 11 carries a spring f<3> to project above the sleeve m. which thus serves as a buffer which must be compressed to a. greater and greater extent by the abutment t as the sleeve m is raised. The application of the brakes on vehicles in which the sleeve m is differently set is thus rendered more nearly simultaneous. The lever 17 may be adjusted manually or automatically according to the load by the movement of the vehicle body upon the springs.