Patent GB-116728-A (GB)
Title: Improvements in Triple Valves for Air Brake Apparatus.
Inventor: CROSS WILLIAM
IPC: B60T15/30
Filed: 1917-04-04
Abstract: 116,728. Cross, W., (Miller, H. 1.). April 4, 1917. Fluid - pressure. - Modifications of the triple valve described in Specification 100,636 comprise chiefly : - a valve 62 actuated in emergency applications to vent the train-pipe to atmosphere; a valve 43 between the chamber 41 and the brake cylinder and actuated with the valve 42 between the auxiliary reservoir chamber 4 and the chamber 41 whereby passage of air from the chamber 41 to the brake cylinder is permitted only when the valve 42 is opened; and means for restricting the feed from train-pipe chamber 2 to chamber 4 to prevent overcharging of the auxiliary reservoirs particularly at the forward part of the train. The valve is shown in two parts comprising respectively the parts for securing service applications and the release of the brakes (Fig. 2) and those for emergency applications (Fig. 3). The chambers 2, 4 connected respectively to the train-pipe and the auxiliary reservoir are separated by the abutment 3 which passes loosely the reduced end 17 of stem 6 which is screwed into abutment 24. Conical valve seatings are provided on the abutment 3 and stem 6 at 9 and 7 and radial and longitudinal passages 17<a> 17<b>, 17d are formed in the stem 6. A spring 7<c> tends to seat the valve 9. Upon an increase of train-pipe pressure to release the brakes, the abutment 3 and stem ti are moved upwardly, thereby opening the exhaust valve 35. The upward movement of the stem 6 is stopped when the nut 6<1> comes against the wall 19 and, if the pressure in chamber 2 exceeds that in chamber 4, the movement of abutment 3 continues, seating valve 7 so that feed into the chamber 4 is by way of the restricted passages 17<b>, 17<a>, 17d. When equalization is effected, the valve 9 is seated by spring 7<c>. In the intermediate position in which both valves 9 and 7 are seated, air can pass freely around the stem 17 into chamber 4. In originally charging the apparatus, if the rise in train-pipe pressure is rapid, the restricted passage 17<b>, 17<a>, 17<d> only will be opened; if the rise in pressure is slow, both valves 9 and 7 will be unseated and the reservoir will be rapidly charged. The abutment 24 separates chamber 21, connected by passage 22 with chamber 41, Fig. 3, from the chamber 25 connected at 25<a> to the brake cylinder. A stem 33 carrying valves 32, 35 slides in the valve cage 28 on the abutment 24 When, in an application of the brakes, these parts move downwards, the exhaust, valve 35 is seated and the valve 32 is lifted against the influence of a spring 34<a> to admit air from the chamber 2 through orifices 12, and stem 6 to the chamber 25. The valve 35 has a loose connexion with the stem 33 by pin 34 so that it may seat truly. A non-return valve 32<a> is disposed in stem 6. Chamber 39<a>, Fig. 3, is connected to the train-pipe at 1<a> and air feeds therefrom into chamber 81. When an emergency train-pipe pressure reduction is effected, the pressure in chamber 81 depresses the abutments 63 thereby unseating valve 69 connected to bar 68 so as to permit train-pipe air to now from chamber 39<a> past check-valve 73<a> to chamber 41. This raises the abutment 39 which, by means of yoke 55, seats the valve 51 to close the chamber 41 to exhaust passage 61 and opens the communication between the auxiliary reservoir chamber 4 and chamber 41 by pipe 41<c> and between the chamber 41 and the brake cylinder chamber 25 by pipe 41d. According to the present construction, these connexions are controlled by a pair of valves 42, 43 attached to a bar 44 connected to the yoke 55 so that these valves move together. By this arrangement, air is prevented from passing from the brake cylinder to the chamber 41 and thence to atmosphere and there is no communication between chambers 41 and the brake cylinder except when the valve 42 is opened to admit air from the auxiliary reservoir chamber to chamber 41. Venting of the train-pipe to atmosphere in emergency applications is effected by the valve 62 in chamber 39<a> adapted to be opened by the abutment 63 and a lever 65. The means of communication between the chambers 39<a> and 81 comprise a restricted passage 73, 74 in the head 60 of the fixed part 72 and a wide passage 71<a> in a member 71 screwed into the dome 64 carried by the abutment 63. A flange 76 on the member 71 is normally raised from its seating on the part 60 so that air can feed from the chamber 39<a> between the part 72 and dome 64 under the flange 76 and through the wide passage 71<a> to the chamber 81. When the abutment 63 is depressed, the flange 76 is seated and equalication between chambers 81 and 39a takes place only through the restricted passage 73, 74. The time required to effect this equalization after an emergency application of the brakes can be regulated by a screw 75 in the passage 73.