Gm Global Technolgoy Operations, Inc.

Harald H Lorenz

James L Coulter

A duo servo drum brake has an adjusting lever pivoted on the secondary brake shoe and engaging the star wheel of an adjusting screw acting between adjacent ends of the primary and secondary brake shoes. An adjusting rod for operating the adjusting lever during forward braking actuation is pivotally connected to the secondary shoe rim near the adjusting lever, and the pivotal connection is infinitely adjusted for brake wear.

Automatic brake adjuster with automatically adjusted steady point

A disc brake actuating and adjusting mechanism including both hydraulic actuation for service brake operation and mechanical actuation for parking brake operation. The brake apply mechanism is separated from the adjuster mechanism and a ball ramp arrangement is utilized for parking brake actuation. Adjustment is maintained by a spring motor driving an adjusting nut. Brake release results in a net motion of the bolt on which the nut is threaded, separating the nut and the ball ramp output member at a clutch face. The spring motor then runs the nut on the bolt until the clutch face is again tightly engaged. When the brake is mechanically applied, the clutch face is loaded to prevent adjustment. The same lockout arrangement prevents adjusting nut rotation during hydraulic apply.

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Bloomfield Hills, MI, United States of America

Harald H Lorenz