Automatic brake adjuster

Claim 2

An automatic brake gap adjuster for a powered and wheeled vehicle, comprising in combination of: actuator means adapted for expanding a pair of movable brake shoes against a rotatable brake drum by means of an expandable piston and cylinder assembly ; parking lever means mounted in proximity to said actuator means and comprising at least two link members; automatic adjusting means comprising a screw engaging stringer member, a ratchet wheel having outer peripheral teeth, and an adjusting lever adapted for rotating said ratchet wheel, and being mounted on said parking lever means; and a further lever means having one end maintained in engagement with said expandable piston for unitary movement therewith and its opposite end engaging said adjusting lever for disabling said automatic adjusting means upon actuation of said actuator means and for allowing said automatic adjusting means to actuate upon actuation of said parking brake lever means.

Claim 3

Automatic brake gap adjuster comprising in combination of: a backing plate mounted on a stationary of an automotive vehicle; a hydraulically operated actuator mounted on said backing plate; a pair of hydraulic pistons expandably and contractably mounted in said actuator; a brake drum mounted on said backing plate rotatably in unison with a vehicle wheel; a stationary anchor fixedly mounted on said backing plate; a pair of brake shoes positioned between said actuator and said anchor and adapted for sliding cooperation with said brake drum when said shoes have been expanded; back spring means tensioned between said brake shoes; a stringer mounted in proximity to said actuator in parallel thereto, said stringer being provided with a rotatable toothed wheel threadedly coupled with said stringer; a parking lever pivotably mounted on one of said shoes and in operative engagement with said stringer; a further lever mounted pivotably on said parking lever and adapted for operative engagement with said ratchet wheel; a stopper lever arranged between said one of brake shoes and said actuator and adapted for engagement with last-mentioned lever upon actuation of said actuator; and spring means tensioned between said stringer or a main body and said last-mentioneD lever; the adjusting operation for correcting the brake gap between shoe and drum being performed only upon actuation of the parking brake and the adjusting operation being disabled upon actuation of said actuator.

Claim 4

Automatic brake gap adjuster comprising in combination of: a backing plate mounted on a stationary of an automotive vehicle; a hydraulically operated actuator mounted on said backing plate; a pair of hydraulic pistons expandably and contractably mounted in said actuator; a brake drum mounted on said backing plate rotatably in unison with a vehicle wheel; a stationary anchor fixedly mounted on said backing plate; a pair of brake shoes positioned between said actuator and said anchor and adapted for sliding cooperation with said brake drum when said shoes have been expanded; back spring means tensioned between said brake shoes; a stringer mounted in proximity to said actuator in parallel thereto, said stringer being provided with a rotatable toothed wheel threadedly coupled with said stringer; a parking lever pivotably mounted on one of said shoes and in operative engagement with said stringer; a further lever mounted pivotably on said parking lever and adapted for operative engagement with said ratchet wheel; a stopper lever arranged between said one of brake shoes and said actuator and adapted for engagement with last-mentioned lever upon actuation of said actuator; and spring means tensioned between said stringer or a main body and said last-mentioneD lever; the adjusting operation for correcting the brake gap between shoe and drum being performed only upon actuation of the parking brake and the adjusting operation being disabled upon actuation of said actuator.

Claim 5

Automatic brake gap adjuster as claimed in claim 2, said last-mentioned lever and said stopper lever being kept in operative connection with each other.

Claim 6

Automatic brake gap adjuster as claimed in claim 2, wherein a further spring means is tensioned between said stringer and said shoe.

Claim 7

Automatic brake gap adjuster as claimed in claim 2, wherein said actuator comprises a cylinder body; at least a piston and spring means.

Claim 8

Automatic brake gap adjuster comprising in combination of: a backing plate fixedly mounted on a stationary part of an automotive vehicle; a hydraulic actuator mounted on said backing plate; two hydraulic pistons slidably mounted in said cylinder; a stationary anchor fixedly mounted on said backing plate; a pair of brake shoes arranged between said anchor and said actuator and adapted for operatively engaging with a brake drum rotatably mounted on said backing plate; back spring means tensioned between said brake shoes; stringer means positioned in proximity to said actuator in parallel thereto, said stringer means being provided with a ratchet wheel kept in threaded coupling with said stringer; a parking lever pivotably mounted on one of said shoes and kept in operative engagement with said stringer; a further lever pivotably mounted on said stringer or a main body and adapted for operatingly engaging said ratchet wheel; stopper lever positioned between said one of said shoes and said actuator and adapted for engagement with said further lever upon actuation of said actuator; transmission lever, one end thereof being mounted on said further lever and the other end of said transmission lever being pivotably mounted on said one of the shoes; and spring means tensioned between said further lever and said one of the shoes through said transmission lever, the adjusting operation of the brake gap between said shoes and said drum being performed only upon actuation of the parking brake and said operation being disabled upon actuation of said actuator for service brake application.

Claim 9

Automatic brake gap adjuster comprising in combination of: a backing plate fixedly mounted on a stationary part of an automotive vehicle; a hydraulic actuator mounted on said backing plate; two hydraulic pistons slidably mounted in said cylinder; a stationary anchor fixedly mounted on said backing plate; a pair of brake shoes arranged between said anchor and said actuator and adapted for operatively engaging with a brake drum rotatably mounted on said backing plate; back spring means tensioned between said brake shoes; stringer means positioned in proximity to said actuator in parallel thereto, said stringer means being provided with a ratchet wheel kept in threaded coupling with said stringer; a parking lever pivotably mounted on one of said shoes and kept in operative engagement with said stringer; a further lever pivotably mounted on said stringer or a main body and adapted for operatingly engaging said ratchet wheel; stopper lever positioned between said one of said shoes and said actuator and adapted for engagement with said further lever upon actuation of said actuator; transmission lever, one end thereof being mounted on said further lever and the other end of said transmission lever being pivotably mounted on said one of the shoes; and spring means tensioned between said further lever and said one of the shoes through said transmission lever, the adjusting operation of the brake gap between said shoes and said drum being performed only upon actuation of the parking brake and said operation being disabled upon actuation of said actuator for service brake application.

Claim 10

Automatic brake gap adjuster as claimed in claim 6, wherein said further lever and said transmission lever are kept in operating connection by a detouchable cross-joint.

Claim 11

Automatic brake gap adjuster as claimed in claim 6, wherein said further lever and said stopper lever are operatively connected with each other through a detouchable cross-joint.

Claim 12

Automatic brake gap adjuster as claimed in claim 6, wherein a still further spring means is tensioned between said stringer and one of said brake shoes.

Claim 13

Automatic brake gap adjuster as claimed in claim 6, wherein said hydraulic actuator comprises a cylinder body, at least a hydraulic piston and spring means.