Patent GB-190311912-A (GB)
Title: Improvements in Valve Mechanism for Air Brakes used on Trains of Vehicles
Inventor: EVANS-JACKSON JOHN EDWARD
Filed: 1903-05-25
Granted: 1903-07-02
Abstract: 11,912. Jackson, J. E. Evans-, [International Air Brake Co.]. May 25. Brakes. - A specially-constructed triple valve for use with air brakes on trains of vehicles is employed in connection with an additional reservoir supplementary to, but distinct from, the usual auxiliary reservoir. For ordinary or graduation applications of the brakes, the air is supplied to the brake cylinder from this supplementary or " graduation" reservoir only, the store of air in the auxiliary reservoir being retained intact for use in emergency. In emergency applications, the train-pipe discharges some of its air into the brake cylinder preliminarily to the discharge from the auxiliary reservoir. In the release of the brakes, some of the air in the brake cylinder is returned to the graduation reservoir to be re-used. Fig. 2 shows the construction of the triple valve and the position of the parts when the brakes are released. To charge the reservoirs, pressure is restored to the train-pipe, which is connected at 8<a>, and the air, passing up the port 13, enters a chamber 14. A part of it then goes to the right to charge the auxiliary reservoir, if necessary, through a port 16, check valve 17, port 24 leading into a chamber 20, and a free passage (not shown) leading from the chamber 20 to the auxiliary reservoir 2. Another part of the air passes from the chamber 14 to the left to charge the graduation reservoir by leaking past the piston 15 through a groove 43, and thence through a tubular casing 33 into a chamber 6<a> connected at 7 to the graduation reservoir. The graduation reservoir may be in the form of a coiled pipe or otherwise. To apply the brakes ordinarily, the train-pipe pressure is gradually reduced as usual, and the pressure in the graduation reservoir at 7 then moves the piston 15 gently to the right. The piston-rod has a collar 79, which is attached to a small valve 30 working in a recess in a slide valve 29. The valve 30 is thus moved to the right and uncovers an orifice, which admits air from the casing 33 to the interior of the slide valve. When the slide valve is moved to the right by the piston, the air passes from its interior through a port 37 and a coincident port in the valve seat into a passage 34, then through a valve 72, passage 68, and pipe 3<a> to the brake cylinder. For an emergency application of the brakes, the sudden reduction of train-pipe pressure causes a violent motion of the piston 15 to the right so that the end of the piston-rod opens a valve 19. This action uncovers an annular port 78 communicating with the brake cylinder by a passage (not shown). Air from the auxiliary reservoir, which communicates with the chamber 20, can thus pass directly to the brake cylinder. At the same time, the slide valve 29 will have moved so far over to the right as to allow air from the graduation reservoir at 7 to pass through the port 37 and another port in the valve seat communicating with the upper part of a cylinder 46. The piston 48 is thus forced down and opens the emergency valve 49, which allows the train-pipe air to open a valve 60 and escape into the brake-cylinder pipe 3<a> until the pressure in the cylinder rises beyond the train-pipe pressure. The valve 60 then closes, and a ring valve at the end of its stem opens orifices 67 leading to the atmosphere, allowing of the escape of air from the train-pipe, and of air which leaks past the piston 48 from the graduation reservoir. In releasing the brakes, the piston 15 moves the slide valve 29 into the position shown, so that the passage 34 communicating with the brake cylinder through the valve 72 is connected with the passage 35 leading to the atmosphere. Some of the air from the brake cylinder passes to the graduation reservoir through a second valve 73 on the stem of the valve 72.