US3900085A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Improvement relating to brake adjusters
Assignee: Girling Ltd
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Filing: 1974-03-19
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Granted: 1975-08-19
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Expires: 1994-03-19
Abstract
Abstract An abutment assembly for a piston, e.g. of a hydraulic brake actuator has a nut screw-threaded on a nut and a drive ring meshing with the nut through a reversible screw-thread connection and engaging the piston under spring bias at conical friction surfaces. Differential control means in the form of a slipping ratchet clutch is provided to prevent undesired rotation of the nut due to blows applied to the nut by the piston during knockback.
Inventors
- 👤 Anthony William Harrison
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 13:43
CPC Classifications
F; F16; F16D; F16D65/00; F16D65/38; F16D65/40; F16D65/52; F16D65/56; F16D65/567; F16D2125/00; F16D2125/18; F16D2125/20; F16D2125/34; F16D2125/40
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
158 words
In a piston for a hydraulic brake actuator: a slack adjuster for determining the retracted position of said piston comprising a non-rotatable strut having external screw-thread; a rotatable nut coaxial with the piston and having an internal screw-thread to mate with the external thread on said strut and so form a nonreversible screw-thread connection, said nut being axially displaceable and rotatable relative to said piston; a drive ring also coaxial with said piston and encircling said nut; a reversible screw-thread connection effective between said drive ring and one of said nut and piston; cooperating friction surfaces effective between said drive ring and the other of said piston and nut; resilient means axially biassing said drive ring in a direction to urge said friction surfaces towards one another; and differential control means permitting rotation of said nut by said drive ring for adjustment but restraining reverse rotation of the nut during impact loading of the nut by the piston.
Claim 2
Dependent Claim
158 words
In a piston for a hydraulic brake actuator: a slack adjuster for determining the retracted position of said piston comprising a non-rotatable strut having external screw-thread; a rotatable nut coaxial with the piston and having an internal screw-thread to mate with the external thread on said strut and so form a nonreversible screw-thread connection, said nut being axially displaceable and rotatable relative to said piston; a drive ring also coaxial with said piston and encircling said nut; a reversible screw-thread connection effective between said drive ring and one of said nut and piston; cooperating friction surfaces effective between said drive ring and the other of said piston and nut; resilient means axially biassing said drive ring in a direction to urge said friction surfaces towards one another; and differential control means permitting rotation of said nut by said drive ring for adjustment but restraining reverse rotation of the nut during impact loading of the nut by the piston.
Claim 3
Dependent Claim
78 words
A slack adjuster according to claim 1 in which said differential control means comprises a first control member non-rotatable relative to said piston, a second control member non-rotatable relative to said nut, said control members having mating radially serrated surfaces, and means spring biassing said serrated surfaces towards one another to form a slipping-ratchet clutch which does not hinder rotation of said nut for adjustment but does inhibit rotation of said nut during impact loading from said piston.
Claim 4
Dependent Claim
18 words
A slack adjuster according to claim 2 in which said control members are annular and encircle said nut.
Claim 5
Dependent Claim
37 words
A slack adjuster according to claim 2 in which said spring biassing means comprises an abutment in said piston and a spring acting between said abutment and said first control member to bias the serrated surfaces together.
Claim 6
Dependent Claim
29 words
A slack adjuster according to claim 4 in which said nut has an abutment thereon and said spring biasses said second control member against said abutment on said nut.
Claim 7
Dependent Claim
19 words
A slack adjuster according to claim 4 in which said second control member is formed integral with said nut.
Claim 8
Dependent Claim
54 words
A slack adjuster according to claim 4 in which said piston is hollow and has a plurality of internal longitudinal grooves therein, key members being received in said longitudinal grooves, and in which said first control member has external notches slidably received over said key members to prevent rotation of said first control member.
Claim 9
Dependent Claim
47 words
A slack adjuster according to claim 7 in which said hollow piston has further longitudinal grooves therein, relatively short key members being received in said further longitudinal grooves and serving as a limit stop for engagement by said first control member to limit compression of said spring.
Claim 10
Dependent Claim
69 words
A slack adjuster according to claim 7 further comprising a fixed ring in said hollow piston and a stop in said piston, said fixed ring being urged by said spring against said stop in said piston and having external notches in which said key members are received, said fixed ring having thereon the one of said friction surfaces and threads of said reversible screw-thread connection associated with said piston.
Claim 11
Dependent Claim
50 words
A slack adjuster according to claim 4 in which said nut and said piston have complementary mating abutment surfaces and in which said spring acting on said first control member is effective to urge said abutment surfaces into engagement with one another in the released state of the brake actuator.
Claim 12
Dependent Claim
33 words
A slack adjuster according to claim 1, in which said friction surfaces are in engagement with one another under the bias of said resilient means in the released state of the brake actuator.
Claim 13
Dependent Claim
18 words
A slack adjuster according to claim 1 in which at least one of said friction surfaces is conical.
Claim 14
Dependent Claim
64 words
A slack adjuster according to claim 1 wherein said reversible screw-thread connection is disposed between said drive ring and said nut and comprises an internal thread inside said drive ring mating with an external thread around said nut and wherein said cooperating friction surfaces comprise an external annular surface around said drive ring cooperating with an internal annular surface fixed relative to said piston.
Claim 15
Dependent Claim
22 words
A slack adjuster according to claim 1 in which the first-mentioned resilient means comprises a spring washer bearing againist said drive ring.
Claim 16
Dependent Claim
18 words
A slack adjuster according to claim 1 in which said reversible screw thread connection comprises mating multi-start threads.
Claim 17
Dependent Claim
32 words
A slack adjuster according to claim 1 in which at least a preponderance of the desired normal brake slack is accommodated by axial clearance at at least one of said screw-thread connections.
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) | 1978-08-18 | 1979-02-17 | 1979-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-18 | 1983-02-17 | 1983-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-18 | 1987-02-17 | 1987-08-19 | $7700.00 | Window Closed / Lapsed |