US4243129A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for tightening a screw joint
Assignee: Atlas Copco AB
•
Filing: 1978-03-15
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Granted: 1981-01-06
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Expires: 1998-03-15
Abstract
Abstract A device for tightening screw joints, comprising a motor, a torque responsive slip clutch and an output shaft, said slip clutch comprising a coil-type friction spring which by one of its ends positively engages one of the clutch halves and which, due to torsional pretensioning, engages the other clutch half by a radially acting friction grip. An adjustable auxiliary torsion spring is arranged in parallel with said friction spring in such a way as to increase or decrease the friction grip of the latter relative to said other clutch half and, thereby, increase or decrease the output torque level of the device. The device includes an adjusting mechanism for setting the torsion load of said auxiliary torsion spring.
Inventors
- 👤 Knut C. Schoeps
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 21:28
CPC Classifications
F; F16; F16D; F16D13/00; F16D13/08; B; B25; B25B; B25B23/00; B25B23/14; B25B23/145
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
217 words
A device for tightening screw joints, comprising: a motor; a torque responsive slip clutch coupled to said motor; an output shaft coupled to said slip clutch; said slip clutch including a driving clutch member, a driven clutch member, one of said clutch members having a friction surface, a coil-type friction spring having respective ends, said coil type friction spring being torsionally wound and pretensioned in itself relative to said friction surface and having one of its ends positively coupled to the other of said clutch members, said coil-type friction spring due to said torsional pretensioning engaging said friction surface by a radially acting friction grip, and an auxiliary torsion spring having its ends positively coupled to the ends of said coil-type friction spring and being arranged to apply a torque load in either direction on said coil-type friction spring to selectively boost or counteract the pretension of said coil-type friction spring; and an adjusting means for continuously varying the relative angular positions between one of the ends of said coil-type friction spring and the corresponding end of said auxiliary torsion spring, for varying said torque load on said coil-type friction spring, thereby enabling said auxiliary torsion spring to selectively exert on said coil-type friction spring a friction grip boosting or reducing torsional load of the slip clutch.
Claim 2
Independent Claim
217 words
A device for tightening screw joints, comprising: a motor; a torque responsive slip clutch coupled to said motor; an output shaft coupled to said slip clutch; said slip clutch including a driving clutch member, a driven clutch member, one of said clutch members having a friction surface, a coil-type friction spring having respective ends, said coil type friction spring being torsionally wound and pretensioned in itself relative to said friction surface and having one of its ends positively coupled to the other of said clutch members, said coil-type friction spring due to said torsional pretensioning engaging said friction surface by a radially acting friction grip, and an auxiliary torsion spring having its ends positively coupled to the ends of said coil-type friction spring and being arranged to apply a torque load in either direction on said coil-type friction spring to selectively boost or counteract the pretension of said coil-type friction spring; and an adjusting means for continuously varying the relative angular positions between one of the ends of said coil-type friction spring and the corresponding end of said auxiliary torsion spring, for varying said torque load on said coil-type friction spring, thereby enabling said auxiliary torsion spring to selectively exert on said coil-type friction spring a friction grip boosting or reducing torsional load of the slip clutch.
Claim 3
Dependent Claim
45 words
Device according to claim 1, wherein said adjusting means comprises a setting ring which is rotatably supported on said one of said clutch members to which said friction spring is directly coupled, said adjusting means being connected to one end of said auxiliary torsion spring.
Claim 4
Dependent Claim
26 words
Device according to claim 2, wherein said adjusting means comprises a worm gear for rotating said setting ring relative to said one of said clutch members.
Claim 5
Dependent Claim
28 words
Device according to either of claims 2 or 3, wherein said one of said clutch members is the driving clutch member and is coupled to said output shaft.
Claim 6
Dependent Claim
16 words
Device according to claim 1 wherein said friction surface is provided on said driven clutch member.
Claim 7
Dependent Claim
55 words
Device according to claim 5 wherein said driven clutch member is an elongated member having a generally round outer periphery, said friction surface being provided on said outer periphery of said driven clutch member, said coil-type friction spring being wound over said outer periphery of said driven clutch member for frictionally engaging said outer periphery.
Claim 8
Dependent Claim
20 words
Device according to claim 1 wherein said auxiliary torsion spring is a coil-type spring wound around said coil-type friction spring.
References Cited (Backward Citations)
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US2468193A
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US3370680A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-01-06 | 1984-07-07 | 1985-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-06 | 1988-07-07 | 1989-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-06 | 1992-07-07 | 1993-01-06 | $7700.00 | Window Closed / Lapsed |