GB244928A - Improvements relating to fluid pressure braking apparatus - Google Patents

Abstract

244,928. Winter, H. J., and Westing- house Brake & Saxby Signal Co., Ltd. Jan. 10, 1925. Fluid-pressure. - Electrically-driven vehicles fitted with straight air brakes are provided with means, as described below, whereby fluid under pressure is automatically supplied to the brake cylinder to apply the brakes when the driver releases the handle of the motor-controller. The invention is shown applied to a double-end brake equipment comprising driver's valves 1, main reservoir 2, brake cylinder 3, and main reservoir and train pipes 7 and 12. In the form shown in Fig. 1, a relay valve 4, controlled by an electromagnetically operated pilot valve 13, controls communication from the main reservoir, through. the pipe 7 and a valve 6 to a pipe 10 leading to the brake cylinder. The circuit of the winding 14 of the valve 13 includes a switch 16 adapted to be closed by a button on the motor-controller handle as long as the driver retains his hold on the latter, whereby the valve is held in the position shown, in which air is supplied from the main reservoir to the upper side of the piston 5. Thereby the valve 6 is held on its lower seat and the pipe 10 is connected to atmosphere at 9. A double check valve 11 is interposed between the brake cylinder and the pipes 10, 12, so that, when a brake application is effected by supplying fluid pressure to either of the pipes, the other is cut off from the brake cylinder. If from any cause the driver releases the handle of the controller, the switch 16 opens and the winding 14 is de-energized. The valve 13 then moves to its upper position, in which it disconnects the space above the piston 5 from the main reservoir and connects it to atmosphere at 15. The valve 6 is then raised to its upper seat by main reservoir pressure acting beneath it, so that the pipe 10 is disconnected from the atmosphere and opened to the main reservoir pipe 7. Pressure fluid therefore passes to the brake cylinder past the check valve 11 to apply the brakes. The pressure thus established in the brake cylinder may be limited by loading the valve 6 by a spring. The automatic brake application may be prevented by the driver closing a switch 18 in a shunt 17, as by means of a pedal. In the form shown in Fig. 2, the stem 19 of the pilot volve 13 is mechanically connected to a button 20 carried by the controller handle, so that when the driver releases his hold on the latter the valve is raised to vent the space above the piston 5 through a pipe 22 and the port 15. The pressure in the pipe 22 may, however, be retained by operating a pedal valve 21. In this form valves 13, 21 are provided at each end of the car, and a double check valve 23 is preferably arranged between the valve 4 and the two handles of the pipe 22, Specification 205,356 is referred to.