Patent GB-179556-A (GB)
Title: Improved system of braking for railway trains and other uses
IPC: B60T7/12
Filed: 1922-05-06
Abstract: 179,556. Hallot, P. May 7, 1921 [Convention date].. Void [Published under Sect. 91 of the Act]. Actuated or applied by speed regulators and running axle; force - transmitting mechanism.-Relates to brake mechanism such as described in Specification 139,818, in which power for applying the brakes is derived from a running axle of a vehicle or machine wholly or partly through a centrifugal clutch device so that the braking effort diminishes with the speed, the leverage of the mechanism being adjustable automatically or manually according to the load. The Specification also describes fluid-pressure braking apparatus. Fig. 5 shows a construction of the centrifugal clutch device, comprising springs 13, 13<1> which force the masses 15 against the loose drum 1 about which the band 3, 3<1> is wound, whereby there is derived a braking force a part of which is independent of the speed and a part of which diminishes with the speed so that scotching of the wheels is prevented. The band 3, 3<1> appears also to be wound upon a part of the drum which is rigidly fixed to the axle. There mav be two cables each attached to the brake rigging and to separate winches, one of the winches being driven directly from the axle to give a braking force which is independent of the speed and the other being driven through the centrifugal clutch. In another arrangement a cone clutch is interposed between the drum which is engaged by centrifugal masses, and the winch so that the drum is not stopped when the brakes are applied. Fig. 1 shows an arrangement of railway brake mechanism in which an endless cable 3, 3<1> passing around a drum 1 driven from the axle 2 has stops 6, 6<1> for engagement with the lever 7 connected to the lever 5. The piston rod of the brake cylinder H is connected to the lever 5 and also by a spring r to a lever E by which the cable 3, 3<1> is tensioned, whereby the braking force derived from the drum 1 augments that applied directly to the brake cylinder. Adjustment of the braking force according to the load is effected by slidably mounting the end 18 of the rod 4 on the lever 7 and connecting this end by a cable 19 to a drum 23, Fig. 7, operable manually or by the displacements of the vehicle body on its bearing springs through a second cable 21 connected to the drum 23 and to the axle 2. When the drum 1 forms or drives a winch on to which the cable is wound, the end of the cable may have a sliding attachment to a lever such as 7. Figs. 40 and 41 show one manner in which the force applied by the lever 7 to the lever 5 may be multiplied. Apparently the chain 4 is connected to the lever 5 at 5<1> and passes over a fixed pulley 307 and also over a pulley 308 carried by the lever 7 and adjustable on that lever according to the load by the cables 19, 21. A chain 313 attached to the hand-wheel 314 permits of the brakes being released and of the rotation of the pulley 309. According to Figs. 43 and 44, the lever 7 is horizontal and a cable 211 is connected to a part 204 slid able along the lever according to the load by means of an endless chain 200 and a cable 19. Fig. 52 shows an arrangement in which the centrifugal clutch drum driven from the axle actuates the brakes by the engagement of a projection 11<m> thereon with a link 10<m> connected to a lever 7<m>. A rod 12<m> connected to the brake connections 2<m> appears to have an end part 3<m> which can be engaged or disengaged with a pin 8<m> on the lever 7<m> by a chain 4<m>. The link 10<m> is brought into the path of the projection 11<m>, when the brakes are applied by hand, by the spring Rm and rod 13m so as to reinforce the direct manual actuation of the brakes. Fig. 49 shows mechanism for an automobile comprising a lever 302, 307, the part 302 of which is jointed at 303 so that it can be brought into the path of a projection 300 on the drum 105<b> by the brake pedal, the part 307 being connected to the brakes by a spring 308<a> and rod 308. A shoe 311 may be applied to the drum 105<b> by the connection 310 so as to apply a braking action to the drum which decreases with the speed. Fluid-pressure.-Fig. 10 shows an accelerator valve for compressed air brakes which may be actuated either by a sudden decrease or increase in train-pipe pressure and in charging the trainpipe may open a reservoir supply thereto. It comprises differential pistons 54, 54<a> actuating a valve 53 controlling an atmospheric outlet 52. The chambers 56, 57 are connected to the trainpipe by the pipes 58, 59 and ports, some of which are controlled by lift valves 60, 62, 68. Normally the chambers 56, 57 are at train-pipe pressure, but if this is suddenly reduced the valves 60, 62, are closed and air escapes from the chambers by the small ports 61, 67 respectively, but as the capacity of the chamber 57 is relatively large. a pressure is established therein sufficiently superior to that in the chamber 56 to effect the upward movement of the pistons and the opening of the vent valve 53. Also if the train-pipe pressure is suddently increased a superior pressure is established in the chamber 57, since in this case the valve 68 closes the connection of the train-pipe with the chamber 56. The apparatus may be attached to a reservoir R provided with a valve 73 having a projection 72 for engagement by the piston stem 70, whereby the valve is opened to connect the reservoir to the trainpipe by the pipe 74 to augment the charging thereof and assist the release of the brakes. Apparatus is shown for producing a wave of compression in the train-pipe, for actuating an accelerator valve such as just described. It comprises a weight which may be dropped upon the piston of a compression chamber or a capsule containing a gas-generating substance, adapted to be punctured automatically when a danger signal is overrun. Fig. 21 shows apparatus which may be used for producing a wave of compression in a vacuum train-pipe 401 for effecting the rapid actuation of accelerator valves. A weight 409 can be dropped on to a piston 406 so as to produce a compression in a chamber 400' which forces a piston 403 to uncover the vacuum train-pipe 401, to which the compression is then transmitted. A pipe 412 connected to a compressed air supply may be added. Fig. 20 shows a combined distributor and accelerator valve for vacuum brakes. It comprises a pair of diaphragms n, o connected together, the lower one being provided with a lift valve r<1>. The chamber m between the diaphragms is connected to the brake cylinder at m<1>. A chamber t<1> fixed in the chamber m is open to the atmosphere at G and has a lift valve s'. The lower chamber l is connected to the vacuum reservoir and the chamber h<1> to the train-pipe T. Normally the diaphragms n, o are raised as shown so that the brake cylinder is connected to atmosphere by the valve s<1>, which is held raised by contact with the valve r<1>. Also the reservoir is open to the trainpipe by valve e<1> and passage p. If air is admitted to the train-pipe the diaphragms are lowered, the valve r<1> engages the bottom part of the valve casing and is opened, thereby connecting the brake cylinder to the reservoir and applying the brakes. At the same time apparently the piston z<1> actuates the valve y' to open the train-pipe to atmosphere at the port g, equalization of pressure between the train-pipe and the chamber h above the piston being re-established by the passage c<1> when the valve y<1> is uncovered. A train-pipe venting valve similar to the valve y<1> and co-operating parts is described for compressed air brakes. The valve s' may also be opened to release the brakes by pushing upwardly the rod h'. The ball valve v<1> is provided to restrict communication between the chamber h<1> and the chamber above the diaphragms at the head end of the train. Fig. 26 shows a distributor valve for compressed-air brakes. The upper piston X is in this case of greater diameter than the lower piston X<1>. The chamber D is connected to the brake cylinder at 707, and the auxiliary reservoir to the chamber B at R. Normally the brake cylinder is open to atmosphere by the valve 705 and outlet E and the reservoir is charged by the passage 701 and valve 702. When the train-pipe pressure is reduced the brake cylinder is opened to the reservoir by the valve 704, the supply being diminished after the application of the brake blocks by the coned part 704<1> of the valve. With a substantial reduction in train-pipe pressure the valve 710 is unseated to vent the train-pipe to the brake cylinder. Excessive increases and reductions of pressure such as occur at the head end of the train are moderated respectively by a ball valve 716 and the valve 717 and ports 718 which restrict the communication of the train-pipe with the valve. The valve permits graduated application and release of the brakes. Fig. 8 shows a valve for two-chambered compressed-air brakes in which, upon increasing the pressure in the trainpipe 43, the valve 39 connects the two chambers through the pipes 42, 44 to effect the rapid release of the brakes. Charging of the chambers is restricted when the train-pipe pressure is relatively high by a valve 35<1> which then leaves open only the restricted port 38. The valve x is not described. Mechanism for opening a pressurereducing valve in the event of the wheels becoming scotched comprises in one form, Fig. 16, a reducing valve 353 with an arm A, B, a spring 352 which tends to open the valve and an endless belt 354 with stops 355, 356 one or the other of which tend to hold the valve closed as long as the axle is rotating. A cable 359 connected to the brake-block rigging prevents opening of the valve if the brakes have not been applied. In another form a centrifugal governor driven from the axle operates the valve. Fig. 17 shows an arrangement of two windlasses T adapted to be engaged each with an axle when the brakes are applied