Robert Boschgmbh

Lawrence W Rusk

James E Doolittle

An adjustment arrangement for a non-servo drum brake having a hydraulic actuator that engages a first web of a first brake shoe and a second web of a second brake shoe. The hydraulic actuator on receiving a hydraulic input develops an actuation force for moving the first and second brake shoes from a rest position into engagement with a rotatable member to effect a brake application. An extendible member, that is connected to the first web and the second web, is extendable to define a running clearance in a rest position between the first and second brake shoes and the rotatable member. A lever arm, that is mounted on the first web, engages the extendable member. A resilient member extends between the lever to the second web to urge the first and second webs into engagement with the hydraulic actuator. The lever arm pivots on the first web as the first web moves through the running clearance during a brake application. When the running clearance reaches a predetermined maximum gap, the lever pivots sufficiently to rotate the extendible member and extend the extendible member to establish a minimum gap for the running clearance. The adjustment arrangement is characterized by the first web having a first engagement surface connected to the hydraulic actuator and a second engagement surface connected to the extendible member. The first engagement surface receiving the actuation force from the hydraulic actuator to move the first brake shoe through the running clearance and into engagement with the rotatable member to effect the brake application. The first web has a cantilever arm through which the first engagement surface is connected to the second engagement surface such that movement of the second engagement surface in response to the actuation force is limited as a function of the resiliency of the cantilever arm.

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South Bend, IN, United States of America

Lawrence W Rusk