Robert Boschgmbh

Robert Bosch Technology Corporation

Norman Lee Hostetler

Joseph C Capek

Daniel Ray Zylstra

A drum brake assembly (,) having first (,) and second (,) brake shoes retained on a backing plate (,). The first (,) and second (,) brake shoes have a first end (,) aligned on a hydraulic actuator assembly (,) and a second end (,) aligned on an anchor block (,). An adjustable strut mechanism (,) has an extendable shaft (,) with first end member (,) which engages the first brake shoe (,) and a second end member (,) which engages the second brake shoe (,). The first end member (,) is separated from the second end member (,) by a stem member (,). Stem member (,) has a threaded first end (,) which is mated with the second end member (,) and a smooth second end (,) which is retained in a bore of the first end member (,). The first (,) and second (,) brake shoes are urged toward the hydraulic actuator assembly (,) by a first resilient member (,) and toward the anchor block (,) by a second resilient member (,). The length of the extendable shaft (,) is adjusted by ratcheting a pawl (,) to rotate stem member (,) and establish a predetermined running clearance between the first (,) and second (,) friction pads and drum (,). The hydraulic actuator assembly (,) responds to a first input to respectively move first (,) and second (,) friction pads associated with first (,) and second (,) brake shoes into engagement with a drum (,) and effect a service brake application. A mechanical actuator (,) has a lever (,) which is pivotally connect to an arm (,) that extends in a perpendicular plane from the second end (,) of the extendable shaft (,). An input applied to lever (,) caused end (,) to pivot on arm (,) and axially move the first end member (,) of the extendable strut (,) toward web (,) while variable surface (,) moves toward web (,) and thereby brings the first (,) and second (,) friction pads into engagement with a drum (,) to effect a parking brake application.

Drum brake with duo-actuation

A drum-in-hat brake assembly (10) having first (12) and second (14) brake shoes retained on a backing plate (16) by first (18) and second (20) pins connected to the backing plate (16). The first (12) and second (14) brake shoes are aligned on the backing plate (16) by an anchor post (40) and connected to a reverse actuator (26). The reverse actuator (26) receives an input force to respectively move first (42) and second (44) friction pads associated with the first (12) and second (14) brake shoes into engagement with a drum (46) to effect a brake application. The reverse actuator (26) includes a first lever (52) and a second lever (54), each of which have a flat plate (60,76) that extends through an opening (62) in the backing plate (16). A resilient member (90) located in the opening (62) maintains the flat plates (60,76) in a same perpendicular plane with respect to the backing plate (16). The first (52) and second (54) levers which are connected to the first (12) and second (14) brake shoes and to each other through a semi-circular indentation (70) on the first lever (52) adjacent a first end (56) which receives a semi-circular projection (82) extending from a first end (72) on the second lever (54). A spring (48,50) acting through the first (12) and second (14) brake shoes which holds the semi-circular projection (82) in the semi-circular indention (70) to separate a second end (58) on flat plate (60) from a second end (74) on flat plate (76). An actuation cable (91) connected to the second ends (58,74) provides an input force which causes one of the first (52) and second (54) levers to pivot about the semi-circular indentation (70) and move the second ends (58,74) toward each other while the first ends (56,72) correspondingly move away from each other to provide an input force to effect a brake application.

Growing community of inventors

Walkerton, IN, United States of America

Norman Lee Hostetler