US3851737A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Disc brake with automatic adjusting parking brake
Assignee: Motors Liquidation Co
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Filing: 1974-03-04
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Granted: 1974-12-03
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Expires: 1994-03-04
Abstract
Abstract A disc brake assembly is hydraulic pressure operated for service and mechanically operated for parking. The parking brake apply mechanism includes an automatic adjuster. An apply shaft is threaded through the caliper housing and into the pressurizing cylinder so that it may be rotated by arcuate movement of an apply lever and translate the arcuate movement into linear movement. An adjuster shaft extends through the apply shaft and has a land engaging the inner end of the apply shaft for linear movement therewith. The adjuster shaft has an adjuster nut threaded on its inner end with the threads being of the same hand as the threads of the apply shaft and of a lesser pitch. The adjuster nut is slidably splined into the hydraulically actuated piston and has one end engageable with the interior of the piston head to transmit forces thereto from the adjuster shaft. A ratchet adjusting mechanism on the adjuster shaft and the apply lever operates to rotate the adjuster shaft relative to the adjuster nut when a predetermined arcuate amount of movement of the apply lever is required to actuate the parking brake. The adjuster nut is then moved axially to take up the space between it and the piston head created by brake lining wear.
Inventors
- 👤 J Hewins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 10:42
CPC Classifications
F; F16; F16D; F16D65/00; F16D65/38; F16D65/40; F16D65/52; F16D65/56; F16D65/567; F16D2121/00; F16D2121/02; F16D2121/14; F16D2123/00; F16D2125/00; F16D2125/18; F16D2125/20; F16D2125/34; F16D2125/40
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
439 words
A disc brake comprising: a caliper having a housing, brake shoes mounted therein for braking engagement with a disc, and a piston for hydraulically actuating the brake, said piston being mounted for axial movement in a cylinder formed in said housing; a mechanically actuated brake apply shaft having a bore extending axially therethrough, said shaft extending into said cylinder coaxially with said piston and threadedly engaging said housing for rotational movement and consequent axial movements in brake apply and release directions; an adjuster shaft rotatably mounted in said apply shaft bore and having a land engaging one end of said apply shaft so as to be moved axially therewith and thereby in the brake applying direction of movement of said apply shaft, one end of said adjuster shaft being threaded with a lesser thread pitch than and of the same hand as the threads threadably joining said apply shaft and caliper housing; an adjuster nut splined to said piston so as to be limited to axial movement relative to said piston, said nut also threadedly engaging the threaded end of said adjuster shaft, one end of said nut being axially engageable with said piston in force transmitting relation to limit brake releasing movement of said piston and to apply brake actuating force thereto when said apply shaft is mechanically actuated to move said apply shaft and said adjuster shaft and said adjuster nut axially in the brake apply direction; an actuating lever on said brake apply shaft for rotating said apply shaft by arcuate movement of said actuating lever within a predetermined arcuate stroke angular range; a ratchet wheel on said adjuster shaft having a plurality of teeth thereon circumferentially equally spaced apart at angles therebetween substantially equal to and no greater than the angle of said actuating lever arcuate stroke angular range; a spring loaded pawl pivotally mounted on said actuating lever and riding on said ratchet wheel and, upon arcuate movement of said actuating lever through an angle equal to the angle between adjacent of said ratchet wheel teeth in the brake apply direction, engaging one wheel tooth so as to rotate said ratchet wheel an angular distance substantially equal to said angular range upon return movement of said actuating lever to the brake release position, thereby rotating said adjuster shaft and causing said adjuster nut to move axially in the brake apply direction to adjust the brake; and a latch pawl mounted on said housing and yieldingly engaging said ratchet wheel to prevent rotation thereof in the other direction of rotation for an angular distance greater than the angular distance between two adjacent ratchet wheel teeth.
Claim 2
Dependent Claim
439 words
A disc brake comprising: a caliper having a housing, brake shoes mounted therein for braking engagement with a disc, and a piston for hydraulically actuating the brake, said piston being mounted for axial movement in a cylinder formed in said housing; a mechanically actuated brake apply shaft having a bore extending axially therethrough, said shaft extending into said cylinder coaxially with said piston and threadedly engaging said housing for rotational movement and consequent axial movements in brake apply and release directions; an adjuster shaft rotatably mounted in said apply shaft bore and having a land engaging one end of said apply shaft so as to be moved axially therewith and thereby in the brake applying direction of movement of said apply shaft, one end of said adjuster shaft being threaded with a lesser thread pitch than and of the same hand as the threads threadably joining said apply shaft and caliper housing; an adjuster nut splined to said piston so as to be limited to axial movement relative to said piston, said nut also threadedly engaging the threaded end of said adjuster shaft, one end of said nut being axially engageable with said piston in force transmitting relation to limit brake releasing movement of said piston and to apply brake actuating force thereto when said apply shaft is mechanically actuated to move said apply shaft and said adjuster shaft and said adjuster nut axially in the brake apply direction; an actuating lever on said brake apply shaft for rotating said apply shaft by arcuate movement of said actuating lever within a predetermined arcuate stroke angular range; a ratchet wheel on said adjuster shaft having a plurality of teeth thereon circumferentially equally spaced apart at angles therebetween substantially equal to and no greater than the angle of said actuating lever arcuate stroke angular range; a spring loaded pawl pivotally mounted on said actuating lever and riding on said ratchet wheel and, upon arcuate movement of said actuating lever through an angle equal to the angle between adjacent of said ratchet wheel teeth in the brake apply direction, engaging one wheel tooth so as to rotate said ratchet wheel an angular distance substantially equal to said angular range upon return movement of said actuating lever to the brake release position, thereby rotating said adjuster shaft and causing said adjuster nut to move axially in the brake apply direction to adjust the brake; and a latch pawl mounted on said housing and yieldingly engaging said ratchet wheel to prevent rotation thereof in the other direction of rotation for an angular distance greater than the angular distance between two adjacent ratchet wheel teeth.
Claim 3
Dependent Claim
313 words
A manual disc brake actuator and adjuster mechanism comprising: a housing having therein piston and cylinder means for applying force to brake pad assemblies to actuate a disc brake; a manual brake apply and release mechanism including: a threaded rotatable and axially movable first member threadedly received in said housing, a threaded rotatable and axially movable second member rotatably received in said first member and axially movable therewith, a third member in said cylinder means splined to said piston means so as to be limited only to axial movement relative thereto and threadedly received on said second member so as to be axially moved by rotational movement of said second member and also by axial movement of said second member toward said piston, said third member having an end face axially engageable with said piston means in force transmitting relation; a brake apply lever secured to said first member and manually arcuately movable to rotate said first member in said housing and by the threaded action to axially move said first member; and ratchet means including a toothed ratchet wheel on said second member, a latch pawl on said housing engaging said ratchet wheel to limit arcuate movement thereof in one direction according to the circumferential spacing of adjacent teeth of the wheel, and an adjuster pawl pivotally mounted on said brake apply lever and yieldingly engaging said ratchet wheel and upon sufficient arcuate movement of said brake apply lever in the brake apply direction ratcheting over a tooth of said wheel and drivingly engaging that tooth upon brake releasing movement of said brake apply lever to move said wheel and therefore said second member arcuately relative to said third member to cause said third member by thread action to move axially in the brake apply direction to provide an adjusted position of said piston means in said cylinder means upon brake release.
Claim 4
Dependent Claim
313 words
A manual disc brake actuator and adjuster mechanism comprising: a housing having therein piston and cylinder means for applying force to brake pad assemblies to actuate a disc brake; a manual brake apply and release mechanism including: a threaded rotatable and axially movable first member threadedly received in said housing, a threaded rotatable and axially movable second member rotatably received in said first member and axially movable therewith, a third member in said cylinder means splined to said piston means so as to be limited only to axial movement relative thereto and threadedly received on said second member so as to be axially moved by rotational movement of said second member and also by axial movement of said second member toward said piston, said third member having an end face axially engageable with said piston means in force transmitting relation; a brake apply lever secured to said first member and manually arcuately movable to rotate said first member in said housing and by the threaded action to axially move said first member; and ratchet means including a toothed ratchet wheel on said second member, a latch pawl on said housing engaging said ratchet wheel to limit arcuate movement thereof in one direction according to the circumferential spacing of adjacent teeth of the wheel, and an adjuster pawl pivotally mounted on said brake apply lever and yieldingly engaging said ratchet wheel and upon sufficient arcuate movement of said brake apply lever in the brake apply direction ratcheting over a tooth of said wheel and drivingly engaging that tooth upon brake releasing movement of said brake apply lever to move said wheel and therefore said second member arcuately relative to said third member to cause said third member by thread action to move axially in the brake apply direction to provide an adjusted position of said piston means in said cylinder means upon brake release.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-02 | 1978-06-03 | 1978-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-02 | 1982-06-03 | 1982-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-02 | 1986-06-03 | 1986-12-03 | $7700.00 | Window Closed / Lapsed |