Drum Brake (truck)

Assignment

Drum-brakes appear to be able to assert themselves longer in the utility vehicle- than in in the motor car area, because here, the advantages of the drum-brake are somewhat more emphasized. Less weight is placed on the auto-amplifying characteristics with lower operational force, but rather on the lower production costs, the longer service intervals and, as a rule, the longer service life of the linings. However, the disc-brake is currently catching up rapidly ...

Function

In contrast to the motor car drum-brake, the brake cylinder is installed outside of the brake drum. All that remains inside, is the spreading mechanism and the brake shoes themselves. When being replaced, the linings are riveted on in the workshop. In the case of the motor car, the complete brake shoe is exchanged. Just the same, here the brake shoes are also mounted onto an, indeed somewhat more stable anchor-plate. They also operate on the Simplex-principle. The pivot-point is at the bottom, at the top the spreading apart takes place. This can be done by an S-cam, through transverse mounted rollers (see figure), or by a spreading wedge, through vertically mounted rollers. In this case the brake cylinder is mounted immediately behind the anchor-plate.

With the brake shoe spreading done by an S-cam, this forms the end of the brake shaft, which is turned when braking, through a lever, by the diaphragm cylinder which is mounted onto the axle. The self sdjustment is also integrated into this lever. 11/10