Patent GB-275401-A (GB)
Title: Brake systems actuated by fluid pressure
IPC: F16D65/28
Filed: 1926-07-17
Abstract: 275,401. Anderberg, A., and Anderberg, E. A. July 17, 1926, Fluid-pressure; electric. - A single-chamber brake, an electric solenoid brake or other similar quick-acting approaching means is adapted to bring the brake shoes into contact with the wheels and bv its movement connect one chamber of a two-chamber brake with an auxiliary reservoir, the other chamber being connected to the train pipe, the two-chamber brake applying the main brake pressure. More than one two-chamber brake may be provided to obtain varying braking powers for empty and loaded vehicles. The pistonrod 8 of the single-chamber brake passes through a sleeve 14 carrying the piston 10 of the twochamber brake. On reduction of pressure in the train pipe 1 the single-chamber brake cylinder 6 is connected to the auxiliary reservoir 3 by the triple valve 2 and moves to apply the brakes. Movement of the piston 7 of the single-chamber brake opens a pipe 16 leading to one side of the piston of the two-chamber brake cylinder 9, the other side of this piston being connected to the train pipe by a pipe 17. When the pressure communicated through the pipe 16 overcomes the train-pipe pressure the piston 10 moves to the left and is clutched to the piston-rod 8 by levers 18 provided with friction shoes 19 adapted to engage teeth, grooves, threads or the like on the piston rod under the control of springs 20 which ensure a firm connection but allow longitudinal displacement of the entire clutch device. In a modified clutch device the tube 14 is connected by pivoted rods to a conical sleeve arranged around wedge-like conical clutches surrounding the piston-rod and under spring control. The piston 10 is returned to the release position by a spring 12 or by increasing the train pipe pressure to above that of the pressure communicated through the cylinder 6. The triple valve, Fig. 2, comprises a piston 24 adapted to displace a slide valve 53 by means of springs 31. A space between the upper spring and the abutment. 32 of the piston-rod allows the piston to cover the feed groove 27 for the auxiliary reservoir connected at 26 before moving the slide valve, when the pressure in the train pipe connected at 25 falls on application of the brakes. The connection 29 communicates with the cylinder 6 and in the normal position of the slide valve with an atmospheric connection 30. A spring-actuated ball 33 arrests the slide valve in release and application position by engaging recesses therein, the recess engaged by the ball in application position being deeper so that a greater difference in pressure is required to operate the slide valve in this position and the release of the single-chamber brake is delayed till after that of the two-chamber brake. For unloaded vehicles the single-chamber brake alone need be used and the two-chamber brake cylinder 9, Fig. 1, is cut off from the cylinder 6 and opened to atmosphere by a cock 34. A cock 35 is provided in the connection between the triple valve and the cylinder 6 to throttle this connection when the cylinder 6 acts alone. The cocks 34, 35 may be operated simultaneously by a mechanical connection. The cock 35 may have a branch communicating with the atmosphere in order that the brakes of a single carriage in a train may be released by connecting both cylinders to the atmosphere by these cocks. The communication between the cylinders may be in the form of a channel in the walls of the cylinder frame. In normal position this communication connects the cylinder 9 with the atmosphere through the lower part of the cylinder 6 and thus allows leakage from the train pipe past the piston 10 to escape. In the modification in which an electric brake is substituted for the singlechamber brake a switch operated by the driver's valve or by the triple valve cuts out the solenoid of the electric brake connected to the piston-rod 8 to allow a spring to apply the brake. Movement of this brake is adapted to turn the cock 34 or another valve to connect the two-chamber brake to the triple valve or the auxiliary reservoir. When more than one two-chamber brake cylinder is used, each may be provided with its own clutch device or all the pistons may be connected to the tube 14 and may have varying diameters. Any or all of these brakes may be cut out by threeway cocks or a valve device in which connections from each side of each of the cylinders of these brakes and the connection 16 from the singlechamber brake and the connection 17 from the train pipe pass to the plane disc of this valve device. A rotary valve covers this disc and has cavities adapted to connect all the connections from one side of the twochamber cylinders to the single-acting brake and all the connections from the other side of the cylinders to the train pipe. As the valve is turned the connections from the cylinders in sequence are cut off from the single-acting brake and the train pipe and communicate with a cavity connected to the atmosphere. A spring is provided tending to turn the valve to the position in which only one two-chamber brake is in operation. In order to allow a vehicle to be coupled into a train having brakes working at higher pressures, an adjustable pressure retaining valve may be fitted in the communication between the train pipe and the two-chamber brake.