GB904355A - Improvements in or relating to electro-pneumatic brake systems for rail vehicles - Google Patents

Abstract

904,355. Fluid-pressure brakes. KNORRBREMSE G.m.b.H. Oct. 31, 1960 [Nov. 6, 1959], No. 37333/60. Class 103 (1). An electro-pneumatic brake system for rail vehicles is of the kind comprising a manuallyoperated pneumatic pressure regulator 5 whose regulated pressure is directed to a cylinder 9 containing a double piston 17, 27 for setting the switching position of an electric switch 13, and also to a brake valve 53 and magnetic release valve 55 controlled by the electric switch and arranged respectively for filling a brake cylinder 63 from a compressed-air source and venting it to atmosphere, the arrangement being such that the brake cylinder pressure acts on the double piston 17, 27 for resetting the brake system wherein the electric switch has at or adjacent the ends of a switch arm 33 contacts 35, 37 between which are a fixed pivot 39 and a movable pivot 31 which is movable by the double piston to operate the brake system. In operation, compressed air from a supply pipe 1 charges cylinder spaces 9 and 19 and a reservoir 71 through the regulator 5, and when braking is required the pressure in a pipe 7 is reduced by movement of a handle 3 of the regulator. Since the pressure in the space 9 falls but that in space 19 does not due to a non-return valve 21, the piston 17, 27 moves to the right and rotates the arm 33 about the pivot 39 to close the contacts 35. This closes a circuit including a solenoid 51, and a shut-off valve 67 of the valve 55 closes off the brake cylinder 63 from an atmospheric vent 65. Further movement of the pivot 31 inwardly closes the contacts 37 and a solenoid 49 causes the valve 61 of the braking valve 53 to open and admit air from the brake pipe 1 to the brake cylinder 63. At the same time this air enters a space 29 and moves the piston 17, 27 to the left when the pressure is greater than the value of the initial fall in pressure in the space 9. The contact 37 is broken and the valve 61 therefore closed, giving a brake-holding position. For brake-release the pressure in the pipe 7 is increased by the regulator, the piston 17, 27 moves to the left and the contact 35 is broken to open the valve 67 and hence vent the brake cylinder to atmosphere. In a modification, the regulator 5 may also control the pressure level in a main air pipe which serves to control a brake control valve connected through a double non-return valve to the brake cylinder 63. The actuating device 11 may be connected to a pressure regulator for directly actuating compressed-air brakes and also other magnetic means for controlling and venting brake cylinders may be connected to the conductors 57 and 59, using relays if necessary.