Lucas Industries Public Limited Company

Sigmar H Micke

Malcolm Brearley

Wilfried T Giering

Franz-Helmut Holl

Jorg Thielecke

Braking distribution system for a multi-axle vehicle making allowance

A wedge and roller brake actuator comprises a wedge disposed between opposed tappets with interposed rollers acting to transmit thrust from the wedge to the tappets for brake actuation, a fixed inclined surface engaged by one roller to restrain the wedge for linear movement, and to ensure that one of the tappets normally associated, in use, with the brake trailing shoe, applies its associated shoe in advance of the other tappet, either the roller-engaging surfaces of the wedge and opposed tappet at either side of the wedge are inclined at different angles to the wedge longitudinal axis, or respective adjusters of the tappets are provided with different clearances between threadedly interengaged components thereof so that one tappet is adjusted to maintain its associated shoe nearer to the drum than the shoe associated with other tappet.

Brake actuator

At least one brake shoe (14) comprising a lining support member (16) and two lining sections (20) fastened one behind the other in circumferential direction to the support member (16) is arranged in a brake drum (10) which has a circular cylindrical internal braking surface (12). Each lining section (20) has an at least approximately circular cylindrical friction surface (22) the radius of curvature (R22) of which is smaller than the radius of curvature (R12) of the braking surface (12) and the center of curvature (M22) of which is located such that only a center portion of the friction surface (22) engages the braking surface (12) upon actuation of the brake. In a rectangular coordinate system (X,Y) the origin of which lies on the axis (A) of the brake drum (10) and the abscissa (X) of which is formed by a center line between the two lining sections (20), the center of curvature (M22) of each friction surface (22) has a distance (y 22) from the abscissa which is smaller than the distance (x22) from the ordinate upon actuation of the brake. This shortens the running-in period during which the friction surfaces (22) becomes adapted to the braking surface (12) of the brake drum (10).

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Koblenz-Metternich, Germany

Sigmar H Micke