GB190925870A - Improvements in Air Brakes and Whistle Signals for Railway and like Cars. - Google Patents

Abstract

25,870. Heizer, C. M. Nov. 9. Audible signals. - Relates to whistle signals arranged in connexion with air-brakes for streetrailway cars, the air-pumps which communicate with the brake cylinders and are worked continuously from the vehicle axle being also arranged to communicate with another cylinder which controls the whistle signal through a pedal-operated device. Two pump cylinders 2, arranged under and formed integral with a brake cylinder 3, are provided with pistons 4 operated from the vehicle axle by eccentrics 8, and have openings 11 communicating with the brake cylinder through a flap valve 13, and other openings communicating with a U-shaped pipe 29. The brake cylinder 3 is in communication by pipes 34, 36 with the port 37, Figs. 7 and 8, of a driver's valve F; the pipe 29 communicates by pipes 52, 50 with a whistle-controlling cylinder 47, Fig. 4. This cylinder 47 is connected to the whistle H, Figs. 1 and 2, by a pipe 53, and with the port 42 of the driver's valve by a pipe 45, and is provided with a piston 54, which is normally kept in the position shown by a spring 58, so as to cut off communication between the pipes 50, 53 and establish a comuunication between the pipes 50, 45. The driver's valve is formed with a recess 40, Figs. 6 and 8, fitted with an exhaust port 43, and is governed by a slide 41 formed at one side with an extension 60 and operated through links 63 from a handle 62, which is provided with a pawl engaging three notches 65, Fig. 1, formed in a quadrant 66. Under normal conditions, the handle 62 is in the right-hand notch and the slide 41, occupies the position shown in Fig. 7, thus opening the pumps to atmosphere through the ports 37, 43, and 42, 43. To apply the brakes, the handle 62 is moved to the left-hand notch, whereupon both ports 37, 42 are covered by the slide 41 and the pumps compress air into the brake cylinder. When the requisite degree of brake pressure is obtained, the handle 62 is moved to the intermediate position, thus establishing communication between the pumps and atmosphere through the ports 42, 43 only, as shown in Fig. 8, while retaining the pressure in the brake cylinder. The brakes are released by returning the handle 62 to the right-hand notch. To sound the whistle, the piston 54, Fig. 4, is depressed by means of a pedal 56 so as to establish communication between the pipes 50, 53. The flow of air to the whistle is preferably increased by a temporary movement of the driver's valve to the brakes-applied position before the pedal 56 is depressed.