8953. Dibble, F. Y. April 19, 1909, [Convention date]. Fluid-pressure.-Triple valves for air brakes of railway vehicles are constructed so that the auxiliary reservoirs may be recharged without releasing the brakes, the brake-cylinder pressure being maintained during such recharging by separate release valves arranged in the triple-valve casings. The triple valve is, moreover, provided with a special device for obtaining emergency applications. The triple valve comprises two pistons 7, 24, Fig. 1, working respectively in chambers 3, 4 which open into a passage 49 connected with the train-pipe by a pipe 50. The piston 7 is connected to a valve controlling the admission of air from the auxiliary reservoir to the brake cylinder, the form shown comprising a piston valve 8 which is provided with a circumferential groove 9 and works in a cylinder 5 communicating by passages 21, 22, 20, 19, Figs. 1 and 5, with the auxiliary reservoir 18, and by a port 13 and passage 14 with the brake cylinder. The piston 24 is connected to a separate release valve, such as the piston valve 25 shown, which is formed with grooves 30, 33 and works in a cylinder 6, which is provided with an exhaust port 32 and communicates with the brake cylinder by a port 31 and also with an additional reservoir 34. The cylinders 3, 4 are formed with feed grooves 23, 38, respectively, so that when the parts are in the running position, shown in Fig. 1, the auxiliary reservoir and the reservoir 34 are charged with train-pipe pressure. When the train-pipe is vented for a service application, for example, so that the pressure falls from seventy to sixty-five pounds, the piston 7 moves to the left, as shown in Fig. 6, so as to establish communication between the auxiliary reservoir and brake cylinder, the piston 24 also moving to the left to cut off communication between the brake cylinder and the exhaust port 32. When the auxiliary reservoir pressure has fallen sufficiently, the piston 7 returns to the position shown in Fig. 1, thus opening the feed groove 23 ; on the other hand, however, the piston 24 remains at the left-hand end of the cylinder 4, since the reservoir 34 is charged with air at seventy pounds pressure. The auxiliary reservoir will thus be recharged up to a pressure of sixty-five pounds through the groove 23, and in order to allow the train-pipe and auxiliary reservoir to be recharged to the normal pressure of seventy pounds without releasing the brakes, the piston 24 is formed with a head 40 which is adapted to bear in a fluid-tight manner against a seat 41 when the piston is at the left-hand end of the cylinder 4, thereby reducing the effective area at the left side of the piston 24, and preventing the train-pipe pressure in the chamber 4 from overbalancing the pressure in the reservoir 34. In order to prevent the train-pipe pressure in the cylinder 4 from leaking between the head 40 and seat 41 and thus acting against the face of the head 40, a valve 45 is provided which is normally closed by a spring but is opened by contact of the head 40 with a prolonged stem 48, so as to establish communication between the interior of the head 40 and the atmosphere. When the train-pipe pressure is increased to, say, seventy-five pounds for releasing the brakes, the piston 24 and valve 25 are moved back to the position shown in Fig. 1, thus establishing communication between the brakecylinder port 31 and the exhaust port 32. For emergency applications, there is provided a valve chamber 53 which is arranged in line with the cylinder 3 and formed with ports 55 communicating by passages 56, 57 and a non-return valve 58 with the brake cylinder, and with the passage 49 by a port 62. This valve chamber, in the form shown, is fitted with a piston valve 59, which is normally closed by a spring 61, but is opened as shown in Fig. 5, so as to establish direct communication between the train-pipe and brake cylinder, when the piston 7 moves quickly to the left owing to a sudden reduction in train-pipe pressure for an emergency application.