Patent GB-278111-A (GB)
Title: Improvements in or relating to pneumatic brakes
IPC: B60T15/30
Filed: 1926-07-13
Abstract: 278,111. Kasantzeff, F. July 13, 1926. Fluid-pressure. -Relates to automatic air brakes of the single pipe type in which a controlling-device is connected to the train pipe and the distributor in such a manner that variations in train pipe pressure produce greater pressure variations in the distributor. The train pipe 4, Fig. 2, is connected through a check valve 24 in the feed valve to the auxiliary reservoir pipe 10 which is connected to a chamber 37, Fig. 3, of the distributor, operation of which opens this chamber to the brake cylinder.. The controlling device comprises a large diaphragm 27, Fig. 2, pressed upwards by a spring 30 and connected to a small diaphragm 28 by a spindle 29. A double valve 33 arranged in the spindle 29 connects a chamber 31 above the diaphragm 27 to a chamber 32 below the diaphragm 28 when the spindle is lowered and connects the chamber 32 to an atmospheric outlet 34 when the spindle is raised. The areas of the diaphragms and the tension of the spring are so arranged that on normal pressure existing in the train pipe, the pressure in the chamber 31 which is connected to the train pipe is the same as that in the chamber 32, to which is connected the controlling pipe 12 leading to the distributor, whereas variation of the pressure in the chamber 31 produces greater variation in the chamber 32 and the pipe 12. The device may be shut off or connected to the train pipe by a plug valve 25 which has a small channel 83 for supplying the auxiliary reservoir. A chamber 26 smooths the pressure variations. The distributor comprises three diaphragms 38, 39, 40, Fig. 3, fastened to a spindle 45. The chamber 41 between the diaphragms 38, 39 is connected to the chamber 37 and the chamber 42 between the diaphragms 39, 40 is connected to the pipe 12 leading from the controlling device. In the running position of the driver's valve. the normal pressure is transmitted from the train pipe through the controlling device to the chamber 42 and the same pressure exists in the chamber 41. Variation of train pipe pressure causes a double valve 47 to connect the brake cylinder channel 36 below the diaphragms either to an atmospheric chamber 44 above the diaphragms or to the chamber 37 by a channel 48, whereby air is admitted to the brake cylinder. In a modification of the invention the train pipe 4, Fig. 4, is connected through a feed valve 5 to the chamber 37 which is connected by a pipe 10<1> to the auxiliary reservoir 6. The train pipe is connected to the space between the diaphragms of the controlling device by a pipe 50, the chamber 54 below the larger diaphragm 27, which is pressed inward by a spring 30<1>, is open to the atmosphere and the chamber 55 is connected to the chamber 52 of the triple valve. A double valve 56 is arranged to connect the chamber 55 to the atmosphere or to a chamber 57 connected to the auxiliary reservoir. This controlling device produces inverse variations. In the modified triple valve the chamber 58 between the largest diaphragms is open to atmosphere and the chamber between the smaller diaphragms is adapted to be connected by a plug valve 60 to the atmosphere for load braking or to the chamber 63 by a passage 62 for light braking; in the first case the area difference between the largest and smallest diaphragm is effective for the movement of the diaphragm and in the second case a smaller area of difference between diaphragms 38 and 39 is effective for this purpose. As in the previous case a double valve 47 admits or exhausts air to or from a chamber 37 connected to the brake cylinder. In a further modification of the invention the triple valve arranged as in Fig. 4 is provided with a controlling device comprising a further diaphragm 73, Fig. 6, attached to the spindle 74 connecting the other diaphragm and having a chamber 75 adjoining its outer face which is charged from the auxiliary reservoir by a pipe 66 with air at a constant pressure by a constant pressure valve 77 of the usual double valve type comprising a diaphragm 78 enclosing an atmospheric chamber and having a loading spring 80 and a valve 81. This triple valve operates by variation of pressure in the chamber 70 which is connected to the train pipe 65 by a channel 71 and a chamber 72.