Patent GB-1269966-A (GB)
Title: Braking devices for wheels, for example rail vehicle wheels
IPC: B61H11/14
Filed: 1969-09-15
Abstract: 1,269,966. Combined disc and tread brakes; combined disc and shoe (drum) brakes. KNORRBREMSE G.m.b.H. 15 Sept., 1969 [17 Sept., 1968], No. 45454/69. Heading F2E. A braking device for a wheel, e.g. a rail vehicle wheel, comprises a combination of three brake blocks adapted to be pressed by common actuating means, acting through a connecting linkage, respectively against opposite sides and an outer edge of a rim portion of the wheel, wherein one of the brake blocks is arranged to exert a radially-directed force component on to the connecting linkage during braking, the connecting linkage being such as to utilize this component to press one of the other brake blocks against the rim portion. In Fig. 1, an actuating member (not shown or described), exerts an expanding force in accordance with arrow 13 during braking. Brake levers 10, 11 are thereby rotated about their pivot connections with a cross-rod 12, the cross-rod 12 being resistant to bending or flexion, and thus force brake blocks 7, 8 against frusto-conical side flanks 5, 6 of the rail vehicle wheel rim 3, respectively. Brake blocks 7, 8 then each transmit to the brake levers 10 and 11 a force component directed radially inwardly of the wheel 1. These force components are transmitted through the pivots of the brake levers 10, 11 to the crossrod 12, and from rod 12 to brake block 9 bearing against the wheel tread 4. For taking up wear on the brake blocks a linkage-adjustment means 14 may be included in rod 12.  In Fig. 2 a U-shaped stirrup 15 is located over the wheel rim 3, one side of the stirrup carrying a brake block 8, the bar part 20 carrying a brake block 9, and the other side of the stirrup incorporating a cylinder 16 with piston 17 operable on a brake block 7. When pressure medium is introduced to cylinder 16, brake block is 7 is forced against frusto-conical flank 5; an oppositelydirected force then acts on stirrup 15 by which brake block 8 is forced against flank 6; the radially-inward component of the pressureapplying forces of brake blocks 7, 8, causes a displacement of the stirrup 15 inwards until brake block 9 is pressed against the wheel tread 4. In Fig. 3 the side flanks 21, 22 of the wheel rim 3 are flat instead of frusto-conical, and are associated with cylindrical inner surfaces 23, 24 respectively. Angular brake blocks 7<SP>1</SP>, 8<SP>1</SP> are pivoted on the ends of brake levers 25, 26, respectively, while brake block 9 is pivoted at 29 to the pivot of draw-bars 27, 28 pivoted to brake levers 25, 26 respectively. When, during braking, brake levers 25, 26 are forced apart in accordance with arrow 13, initially brake blocks 7<SP>1</SP>, 8<SP>1</SP>, are pressed against flanks 21, 22. Drawbars 27, 28 are then drawn apart so that brake block 9 is forced against the wheel tread 4. The force of reaction to the pressing of brake block 9 against wheel tread 4 is transmitted through draw-bars 27, 28 and brake levers 25 and 26 to brake shoes 7<SP>1</SP>, 8<SP>1</SP> respectively, causing these brake shoes to be pressed outwardly against surfaces 23, 24.  Ventilating fins (not shown or described) may be arranged radially inward of the rim to improve cooling. Brake block 9 cleans the wheel tread.