Patent GB-128443-A (GB)
Title: Improvements in or relating to Apparatus for Electrically Controlling Air-brakes.
Inventor: MELLERSH-JACKSON WILLIAM JOHN
IPC: B60T13/66
Filed: 1918-07-24
Abstract: 128,443. Jackson, W. J. Mellersh-, (Waterhouse, E. P., and Prince, B. A.). July 24, 1918. Fluid-pressure.-Relates to train brake-apparatus in which a pilot valve electrically controlled as by means on the track is adapted to release air from one face of an abutment connected to a brake-pipe vent valve, and comprises a manual valve adapted to admit pressure-air to the abutment, to re-close the valve, only when the passage leading from the abutment to the pilot valve is closed. Premature closing of the vent valve is thus prevented. A second manual valve permits the cutting out of the whole automatic apparatus and both valves have registering means. Pressure-retaining valves limit the brake-pipe pressure reduction in an application of the brakes. The apparatus comprises a casing 4 connected by upper and lower passages 4<11>, 4<1> to the brakepipe 3<1> which is connected at its upper part to the engineer's valve (not shown). A brake-pipe-seating valve 7 with abutment 6 is disposed in the casing 4 and the rotary member 11 of a manual valve is seated on the upper part of the casing. Passages 17, 18 leading from the abutment chamber 6' are adapted to be connected by a passage 18<1> and a cavity 16<1> in the valve member 11, respectively to a passage 19 connected to the main reservoir and a passage 22 in which the pilot valve 24 is disposed. In the running position shown, the brake-pipe pressure acting beneath the abutment 6 equalizes through a groove 29 to the upper side of the abutment, the cavity 16<1> in the manual valve 11 connects the abutment chamber 6<1> with the passage 22, and the pilot valve 24 is closed. The vent valve 7 therefore remains closed. If the pilot valve 24 is opened, the pressure chamber 6<1> is released and the vent-valve 7 moves to the open position in which it connects the brakepipe passage 4 with the exhaust-passage 30 and the brakes are applied. To return the vent-valve 7 to the closed position, the valve 11 is moved by its handle 12 to close the passage 17, 22 and to connect the passages 28, 18 so that air from the main reservoir is admitted to the chamber 6<1>. The automatic apparatus can be cut out as a whole by a manual valve 55 normally in alinement as shown with the partition 56 between the brake-pipe passages 4<1>, 4<11>. This permits release of the brakes if the train should stop before the pilot valve has re-closed, thus avoiding the necessity of leaving the valve 11, 12 in the cutout position. Registering means for the valve 55 comprises a finger 59, Fig. 1, on the pivot of the hand-lever 58 of the valve, and a pawl 60 engaged by the finger and engaging a ratchet 61 on the dial 62. The dial is re-set by a pinion 64. The actuation of the valve 11, 12 is registered by a dial 66, Fig. 2, carrying a pawl 68 engaged by a ratchet 69 on the valve spindle. The reduction of pressure in the brake-pipe when the brakes are applied is limited to about 20 pounds per sq. in. by pressure-retaining valves 32, 33 connected to the passage 30 and having exhaust ports 44, 45 and springs 36, 37 adjustable by nuts 38, 39. The valve 32 is for high-pressure working, and is rendered operative by cutting out the low-pressure valve 33 by a cock 42. The means for actuating the pilot valve 24 may comprise a commutator 48 which normally connects the valve magnet 26 to a generator 46, and is actuated by a magnet 49 also normally connected to the generator. A track ramp 52 by engaging a contact 51 is adapted to break the circuit of the magnet 49 and loop it into a circuit comprising the running rails, and if the conditions are abnormal the magnetization of the magnet 49 is thereby varied and the commutator 48 shifted to break the circuit of the valve magnet 24 and apply the brakes.