Introduction/Operation
Introduction
Spicer® brand self adjusting brake adjusters compensate for wear in brake shoe linings caused by normal braking operation. Upon brake application, the brake adjuster assembly rotates, rotating the brake camshaft. The camshaft moves the shoes into contact with the drum.
During brake application and release, the adjuster mechanism rotates the camshaft slightly to maintain the correct
Operation
The Spicer® brand self adjusting brake adjuster is a clearance sensing brake adjuster that maintains a nominal distance or clearance between lining and drum. The clearance notch in the rack corresponds to this normal
Figure 1.)
When the brake applies:
•The rack moves upward and rotates the
•Brake application torque presses the wormshaft against the coil spring. Wormshaft movement releases the cone clutch.
When the brake releases:
•The coil spring presses against the wormshaft, engaging the cone clutch.
•The rack is pulled back to its original position in the clearance notch.
•Any lining wear causes the rack to turn the locked one- way clutch while rotating the wormshaft via the locked cone clutch.
•The wormshaft rotates the wormwheel and camshaft, adjusting the brakes.
NOTE: A properly working Automatic Slack Adjuster does not require manual adjustment while in service. The manual adjuster hex is intended for use during adjuster installation and brake overhaul.
WARNING: Automatic slack adjusters should not be repeatedly adjusted to correct excessive in service pushrod stroke, because this condition indicates that a problem exists with the automatic adjuster, with the installation of the adjuster or with related foundation brake components which manual adjustment will not correct.
CLUTCH
CONE
CLUTCH
WORMSHAFT
COIL
SPRING
RACK
CLEARANCE
NOTCH
CONTROL | CONTROL ARM | |
ANCHOR BRACKET | ||
ARM | ||
|
Figure 1 Components of the Brake Adjuster
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