Patent GB-110149-A (GB)
Title: Improvements in and relating to Fluid Pressure Braking Apparatus.
Inventor: TURNER WALTER VICTOR
IPC: B60T13/68
Filed: 1917-02-27
Abstract: 110,149. Turner, W. V. Oct. 6, 1916, [Convention date]. Fluid-pressure.-Relates to train brakes which are adapted for both electric and pneumatic control and in which the brake cylinders are supplied from the auxiliary reservoirs in electric as well as pneumatic applications. If supplementary reservoirs normally connected to the auxiliary reservoirs are provided for effecting a graduated release or other purpose, the pressure reduction on the auxiliary reservoir side of the pneumatically controlled valve in electric applications may be insufficient to prevent its movement to application position by the train-pipe pressure reduction which is effected by actuation of the driver's valve simultaneously with the actuation of the control switch. According to the invention, a valve is provided for cutting off the supplementary reservoir from the auxiliary reservoir when an electric application is effected. If the release magnet fails when an electric application is attempted, the cut-off valve is not moved, and a pneumatic application is obtained. If the release magnet fails during an electric application, the cut-off valve is returned and the pneumatic valve is actuated so that the exhaust is cut off and release of the brakes prevented. The valve mechanism comprises the valve 1 controlled by train-pipe pressure, electric application and release valves 17, 19 and the cutoff valve 21. In the running position shown, the train-pipe 4 feeds into the auxiliary reservoir 9 by the usual feed groove 29 of the valve 1 and passage 7 and into the supplemental reservoir 28 by passages 30, 31, cut-off valve chamber 24, and passage 26. The brake-cylinder 37 is open to exhaust by way of passages 39, pneumatic valve cavity 42, passage 44, cut-off valve cavity 45 and port 46. The piston-chamber 22 of the cut-off valve is connected to the supplemental passage reservoir 26 by passage 35, the electric release valve 18 and passage 15 and the pneumatic pressure on the valve piston being thus equalized, the cut-off valve assumes the position shown under the influence of the spring 36. To make an electric application, the valves 17, 19 are both energized. The movement of the release valve 18 vents the cut-off piston chamber 22 by way of passage 35 and port 47, and the cut-off valve therefore moves to the left whereby the passage 31 from the pneumatic valve 1 becomes closed to the cut-off valve chamber 24 and thus to the supplemental reservoir. The brake-cylinder exhaust port 46 also is closed and the chamber 52 of a relay piston valve 54 is vented to the brake cylinder by way of passage 51, cavity 48, passage 49, the electric application valve 20, and passages 57 and 39. The consequent unseating of the relay valve 54 connects the brake cylinder to the auxiliary reservoir through passages 55, 53. The valve 54 seats by equalization through the port 54 when the application valve 19, 20 is de-energized. The relay valve 54 may be dispensed with and the brake cylinder be supplied through the valve 20 but the provision of the relay valve ensures a more rapid and direct supply. The connexion of the passages 31 and 53 through cavity 58 when the cutoff valve is in the actuated position provides additional communication between the train-pipe and the auxiliary reservoir during electric applications so that the pressures are maintained more nearly equal during electric applications, thus ensuring prompt action of the pneumatic valve 1 in effecting a graduated release. If the electric release valve 18 fails to act in making an application, the cutoff valve does not move and the connexion between the relay valve 54 and the application valve therefore remains closed, but the reduction in train-pipe pressure due to the actuation of the driver's valve moves the valve 1 to effect an application. If the current in the release magnet circuit fails during an electric application the valve 18 closes the exhaust port 47 to the chamber 22 of the cut-off valve and re-opens this chamber to the supplemental reservoir by way of passage 15 so that the cut-off valve returns to the release position shown, but the consequent connexion of the supplementary reservoir to the auxiliary reservoir and chamber 6 of the valve 1 effects the movement of the graduating valve 11 to close the communication between the brake cylinder and the exhaust port 46, thereby preventing release of the brakes.