GB1458361A - Vehicle brakes - Google Patents

Abstract

1458361 Disc brakes; brake elements; transmitting mechanisms; wear adjustment GIRLING Ltd 20 Dec 1973 [5 Jan 1973] 852/73 Heading F2E A vehicle disc brake comprises a plurality of elongated friction members 2 having ends engageable with a rotor 7 and being supported in slots 3 in a casing 1, the friction members 2 2 being applied to the rotor 7 by an actuating mechanism including a beam 9 screwed to an adjuster screw 10 extending through the casing 1 alongside the friction members 2. In the illustrated embodiment the rotor 7 is a railway vehicle wheel and the casing 1 extends substantially the full length of an axle, terminating close to the inner surfaces of wheels 7 which act as braking surfaces for co-operation with respective sets of friction members 2. The casing 1, which may be in axial sections, is supported against drag forces but has a degree of "end" float to accommodate wheel set end float. The members 1 project through apertures 6 in the casing 2, and during braking drag forces are transmitted to side edges 5 of the apertures 6. The inner end of each member 2 is supported by a metal cap 8, preferably having a prestressed resilient means, such as a pair of belleville washers (11) through which braking forces are transmitted by the beam 9 which acts on all the caps 8-this serves to equalize the forces. The beam 9 which is keyed against rotation in slots 3 is movable via screw 10 by actuation of a wedge expander 12 located at the mid-point of casing 1-the screw 10 is journalled in a blind bore in the adjacent end of a roller-tappet of the expander 12. The screw 10 extends outwardly through a protective guide tube 19 which may be of friction or other expandible material to be worn away as members 2 wear. To adjust for wear the actuator wedge carries a pawl 13 co-operable with a ratchet wheel 14 mounted on a spindle 15, the outer ends of which have pinions meshing with gear-wheels 18 carried by the respective adjuster screws 10- the pawl 13 becomes effective to rotate the wheel 14 on an actuating stroke of the wedge exceeding distance X. Suitable provision is made to protect the adjuster components against excessive operating loads, e.g. resilient means for storing energy to effect adjustment on the return stroke or a frictional clutch means which slips under excessive loads. As shown, each member 2 is arranged to engage the whole swept area of the braking surface. If desired a larger number of friction members may be employed some of which engage an inner annular zone of the swept area, while the rest engage an annular outer zone.