Slack adjuster for cam brakes
OwnerFaust Hagininventor
Life of this patent
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Abstract
A cam actuated brake adjuster reduces automatically the clearance between the brake lining and the brake drum which exists when the brakes are released, if this clearance exceeds a predetermined value. A one-way drive mechanism which adjusts the angular position of a camshaft with the aid of a worm gear is actuated by an adjusting rod assembly, which yields to a given adjusting force corresponding to a given brake force, to prevent an excessive adjustment which might result from a drum distortion caused by the application of a great braking force.
Claims18
In an apparatus for adjusting a predetermined clearance between a brake shoe (37) and a corresponding brake drum (38), including a housing rotatable about an axis, actuating lever means (1) forming part of said housing, a worm wheel (6) journalled in said housing, brake adjusting means (7) operatively interposed between said worm wheel (6) and said brake shoe (37), shaft means (4) journalled in said housing and having a free end, worm means (5) supported by said shaft means for meshing engagement with said worm wheel (6), force transmitting means including a force limiting member operatively arranged to respond to a movement of said lever means rotating said housing about said axis (2) for rotating said worm means, the improvement wherein said force transmitting means comprise a one-way clutch mechanism and linkage means (8, 15, etc.) operatively arranged to transmit a rotational movement of said actuating lever means and thus of said housing through said clutch mechanism to rotate said worm means (5), said one-way clutch mechanism comprising first bushing means (9) operatively connected to said linkage means and rotatably supported in said housing around said free end of said shaft means, second bushing means (12) operatively located within said first bushing means, said first and second bushing means having respective inner and outer cooperating conical surface means, said second bushing means (12) and said free end of said shaft means comprising cooperating helical threaded means adapted to mesh for transmitting torque to said shaft means, whereby said worm means may be rotated in a stepless manner in the direction of adjustment.
In an apparatus for adjusting a predetermined clearance between a brake shoe (37) and corresponding brake drum (38), including a housing rotatable about an axis, actuating lever means (1) forming part of said housing, a worm wheel (6) journalled in said housing, brake adjusting means (7) operatively interposed between said worm wheel (6) and said brake shoe (37), shaft means (4) journalled in said housing and having a free end, worm means (5) supported by said shaft means for meshing engagement with said worm wheel (6), force transmitting means including a force limiting member operatively arranged to respond to a movement of said lever means rotating said housing about said axis (2) for rotating said worm means, the improvement wherein said force transmitting means comprise a one-way clutch mechanism and linkage means (28, 34) operatively arranged to transmit a rotational movement of said actuating lever means and thus of said housing, through said clutch mechanism to rotate said worm means, said one-way clutch mechanism comprising first bushing means (9) operatively connected to said linkage means and rotatably supported in said housing around said free end of said shaft means, second bushing means (12) operatively located within said first bushing means, said first and second bushing means having respective inner and outer cooperating conical surface means, said second bushing means (12) and said free end of said shaft means comprising cooperating teeth with substantially helical flanks (42a, 42b;
- 43a, 43b) adapted to mesh for transmitting torque to said shaft means whereby said worm means may be rotated in a stepless manner in the direction of adjustment.
Dependencies are inferred from the claim text.