Patent GB-121151-A (GB)
Title: Improvements in Air Brake Apparatus.
Inventor: CROSS WILLIAM
IPC: B60T15/18
Filed: 1917-11-06
Abstract: 121,151. Cross, W., (Automatic Straight Air Brake Co.). Nov. 6, 1917. Fluid-pressure.-Relates to apparatus of the kind de. scribed in Specifications 100,636 and 116,728 whereby, upon a slow reduction of trainpipe pressure for a service application to the brake, the brake cylinders are supplied from the train-pipe augmented by service reservoirs, a quick train-pipe pressure reduction or a slow leakage to zero effecting the connexion of the auxiliary reservoirs to the brake cylinders. The present apparatus comprises a valve E which isolates the service reservoir F from the train-pipe in emergency applications and connects it to the valve mechanism B for opening the auxiliary reservoir C to the brake cylinder D, this valve mechanism B being modified so as to be actuated by the service - reservoir pressure. The service reservoirs also are connected to the brake cylinders in emergency applications. Modified means for venting the train-pipe to atmosphere are included in the valve section B. The service valve section A is substantially the same as is described in Specification 116,728. The train-pipe 1 is connected to the chamber 2 and charges the auxiliary reservoir C through the valves 7, chamber 4, and passage 5. The valves 7 restrict the feed if the trainpipe pressure is. excessive. The brake cylinder D is connected by the passage 25<a> to the chamber 25 normally open to exhaust by valve 35 and passage 36<a>. The chamber 21 is connected by pipe 22 to chamber 41, which is open to atmosphere except in emergency applications. In service applications, the abutments 3, 24 are depressed, closing the valves 7, 35 and unseating the valve 32 to connect the train-pipe chamber 2 to the brake cylinder. The valve section B comprises the abutment 39 separating chambers 40, 41 and connected by a yoke 55 and bar 54 to valves 60, 60<a> normally closing pipes 41<c>, 41d leading respectively to the auxiliary-reservoir chamber 4 and the brake-cylinder chamber 25. The yoke 55 is also connected to a valve 51, Fig. 3, controlling a passage 61 open to atmosphere. The abutment 39 also actuates a valve 43<a> connecting the chamber 40 with the chamber 39<a>, which is connected to the train-pipe at 1<a>. The quick-action venting-valve 46 is actuated by a lever 65 and an abutment 63 which separates chamber 39a from a chamber 81. The chambers 39<a>, 81 communicate by passages 68, 71, 72 in the stem 66 secured to the abutment 63 and sliding in a sleeve 67 in which is formed the passage 72 normally registering with the passage 71. A reservoir 82 augments the capacity of the chamber 81. The valve E comprises a chamber 90 constantly open to the service reservoirs F through pipe 91, a fixed post 94, and an aperture 97 in the abutment 88. A valve seating 98 formed around aperture 97 is adapted to engage a seating on the top edge of the post 94 to cut off the chamber 85 connected. at 87 to the train-pipe. The abutment 88 also actuates a. valve 103 controlling communication, through pipe 106, of the chamber 90 with the chamber 41 of the valve section B. The operation of the valve sections B, E is as follows. Normally, the chamber 40 is maintained at trainpipe pressure by feed around the valve stem 43, and the chamber 41 is vented to atmosphere through the valve 51 so that the abutment 39 is depressed to close the valves 60, 60<a>. Under running conditions and in service applications, the pressure in chamber 81 equalizes through passages 68, 71, 72 with train-pipe pressure in chambers 39<a>, and the service reservoir F has restricted communication with the train-pipe around the valve 98 of the valve section E. If a sudden and pronounced train-pipe pressure reduction is effected, the abutment 88 is depressed, thereby seating the valve 98 so as to cut off the service reservoir F from the train-pipe chamber 85, and unseating the valve 103 so that air is supplied from this reservoir past the check valve 103<a> and through pipe 106 to the chamber 41 of the valve section B. At the same time, the pressure in chamber 81 being unable to equalize with that in the train-pipe chamber 39<a>, the abutment 63 is depressed and opens the venting-valve 46, and, the valve 43a being closed, the pressure in chamber 40 at once falls to atmosphere. The abutment 39 is therefore raised by the service-reservoir pressure in chamber 41, thereby closing the exhaust valve 51 and opening the valves 60, 60<a> to admit air from the auxiliary-reservoir chamber 4 to the brake-cylinder chamber 25 by pipes 41<c>, 41<d> and chamber 41. Service-reservoir air also will be supplied to the brake cylinder from the chamber 41 provided the pressure in this reservoir has not been depleted bv a previous service application. The raising of abutment 39 also opens the valve 43<a>, so that the train-pipe is vented to atmosphere by the valve 46. When the quick-action abutment 63 is depressed, the passage 71 is out of register with the passage 72, so that these passages then communicate only about the stem 66, and equalization of the pressures in chambers 81, 39<a> is thus restricted and delayed to hold the venting-valve open for the requisite interval. Should the train-pipe pressure slowly leak to zero, there being no pressure in chamber 40, the air in the auxiliary reservoir will raise the valve 60 and pass into chamber 41 and thus effect an emergency application of the brakes.