Patent GB-190197-A (GB)
Title: Improvements in load-controlled adjusting means for vehicle brakes
IPC: B61H13/30
Filed: 1921-08-12
Abstract: 190,197. Bulbick, A. Aug. 12, 1921. Force-transmitting mechanism; fluid-pressure. -Vehicle brakes are adjusted in accordance with the load by the displacement of the vehicle body upon the bearing springs; a compression spring and a dash-pot are interposed in the adjusting connections so that sudden movements of the body such as occur in the running of the vehicle are not transmitted to the adjusting means. Fig. 1 shows an application of the mechanism for effecting the adjustment of the leverage of vehicle brake mechanism in accordance with the load. The ends 9, 9<a>, of the pull-rods 1, 1<a> of the brake mechanism proper are adapted to be slid along the crank arms 7, 7a on the rock shaft 8 to adjust the leverage by links 2, 2<a> connected to a T-lever 3 pivoted at 4. The arm 5 of the lever 3 is connected by the link 24 to arms 23, 20 on the shaft 21 and link 19 to a lever 11 pivoted to brackets 10, 17 on the vehicle underframe and bearing spring 18 respectively. The lever 11 is in two parts 11, 12, Fig. 4, connected by a spring 14, the bent ends 11<a>, 12a of each part passing through a hole in the other part so that the lever will " break " if it meets with sufficient resistance. Rigid with the shaft 21 is an arm 30 connected to a pair of dash-pot pistons 27, 27<a> having orifices 34 and working in oil or other liquid. If the vehicle body is suddenly displaced vertically, the lever 11, 12 breaks at the spring joint 13 by reason of the resistance offered by the dash-pot pistons, and if the displacement is sustained, as by a variation of the load, the lever straightens and the pistons are moved so that the displacement is transmitted to the ends 9, 9<a> of the pullrods 1, 1<a> to adjust the leverage. Oscillations of the body, such as are due to the running of the vehicle, will not however be transmitted beyond the part 11 of the lever. Fig. 2 shows an arrangement for a bogie. The parts of the adjusting lever 11, 12 have upturned ends 11<b>, 12b, connected by a spring 14, and the part 11 is pivoted to the bogie bolster and frame at 10 and 17 respectively. The part 12 is connected by a pair of links 40, 37 to .the arm 20 of the dash-pot. The pull-rod 39 of the brake mechanism proper is connected to the pivot 38 of the links 37, 40, and its end 44 has a roller which can travel upon a lever 41 pivoted at 42, to vary the leverage. The lever 41 is linked to a lever 43 which is connected to the brake beams. The apparatus shown in Fig. 2 may be used in connection with the load-controlled pressure-regulating valve for fluidpressure brakes described in Specification 184,834, the arm 20 being connected to this valve instead of to the rod 39, which would in this case be pivoted to the lever 41. Fig. 5 shows another arrangement of spring-controlled lever in which the lever 11<c> pivoted at 10<a> to the bracket 45 fixed to the vehicle body, has one end 11<d> disposed between a pair of springs 14<a>, 14b, one of which, 14b, abuts also against the enlarged part of a rod 47, which slides in lugs 48, 49 in the bracket 45 and engages an axle box of the vehicle at its lower end. The spring 14<a>, which is about half the power of the spring 14b, abuts against the lug 48 and against a ferrule 53 freely mounted on the rod 47. The ferrule 53 normally contacts with a ferrule 51 fixed by a pin 52 to the rod 47. When the vehicle body suddenly approaches the axle-box the spring 14<b> is compressed, pivotal movement of the lever 11<c> being restrained by the dash-pot and the spring 14<a>.