US4023406A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tightening system with torque-time control
Assignee: SPS Technologies LLC
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Filing: 1976-03-31
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Granted: 1977-05-17
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Expires: 1996-03-31
Abstract
Abstract The invention disclosed herein relates to a tightening system including a wrench for applying torque to a fastener system. Associated with the wrench is a control system including measuring means for developing a first signal representative of the torque applied to the fastener. A second signal representative of a constant incremental time is introduced along with the torque signal into gradient calculating means which develops a signal representative of the slope of a torque-time curve which can be plotted for the particular fastener system being tightened. When the gradient signal falls to a predetermined percentage of the maximum previously stored gradient signal, at the yield point of the fastener system or some similarly significant point on the torque-time curve, a control signal is generated stopping the tightening of the fastener.
Inventors
- 👤 John W. Benz, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 21:20
CPC Classifications
B; B23; B23P; B23P19/00; B23P19/04; B23P19/06; B23P19/065; B23P19/066; B25; B25B; B25B23/00; B25B23/14
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
125 words
Apparatus for tightening a threaded fastener system to a predetermined tightened condition comprising: means for applying torque to said fastener system; means for measuring the torque applied to said fastener system and providing a signal indicative thereof; means for developing a signal indicative of incremental time; gradient calculating means receiving said torque signals and said incremental time signals for developing a signal representative of the instantaneous torque gradient of the torque-time curve through which said fastener system is being tightened; and means responsive to said torque gradient signal for determining the yield point or other predetermined tightened condition on the torque-time curve through which the fastener system is being tightened and for developing a control signal when said fastener system is tightened to said point.
Claim 2
Dependent Claim
125 words
Apparatus for tightening a threaded fastener system to a predetermined tightened condition comprising: means for applying torque to said fastener system; means for measuring the torque applied to said fastener system and providing a signal indicative thereof; means for developing a signal indicative of incremental time; gradient calculating means receiving said torque signals and said incremental time signals for developing a signal representative of the instantaneous torque gradient of the torque-time curve through which said fastener system is being tightened; and means responsive to said torque gradient signal for determining the yield point or other predetermined tightened condition on the torque-time curve through which the fastener system is being tightened and for developing a control signal when said fastener system is tightened to said point.
Claim 3
Dependent Claim
61 words
Apparatus for tightening a threaded fastener system in accordance with claim 1 wherein said means responsive to said torque gradient signal includes means for storing a signal representative of the torque gradient of the torque-time curve throughout the tightening region thereof and for developing said control signal when said instantaneous torque gradient signal is a predetermined percentage of said stored signal.
Claim 4
Dependent Claim
27 words
Apparatus for tightening a threaded fastener system in accordance with claim 2 wherein said stored signal is representative of the maximum torque gradient of said torque-time curve.
Claim 5
Dependent Claim
33 words
Apparatus for tightening a threaded fastener system in accordance with claim 3 wherein said control signal is developed when said instantaneous torque gradient signal is approximately two-thirds of said maximum torque gradient signal.
Claim 6
Dependent Claim
37 words
Apparatus for tightening a threaded fastener system in accordance with claim 3 wherein said control signal is developed when said instantaneous torque gradient signal is between approximately 25 to 75 percent of said maximum torque gradient signal.
Claim 7
Dependent Claim
26 words
Apparatus for tightening a threaded fastener system in accordance with claim 1 wherein each of said incremental time signals are developed at equally spaced time intervals.
Claim 8
Independent Claim
114 words
A method of tightening a fastener system to a predetermined tightened condition comprising the steps of: applying torque to said fastener system; measuring the torque applied to said fastener system and providing a signal indicative thereof; developing a signal indicative of incremental time; developing a signal representative of the instantaneous torque gradient of the torque-time curve through which said fastener system is being tightened base upon said torque and said time signals; and determining the yield point or other predetermined tightened condition on the torque-time curve through which the fastener system is being tightened, responsive to said torque gradient signal, and developing a control signal when said fastener system is tightened to said point.
Claim 9
Independent Claim
114 words
A method of tightening a fastener system to a predetermined tightened condition comprising the steps of: applying torque to said fastener system; measuring the torque applied to said fastener system and providing a signal indicative thereof; developing a signal indicative of incremental time; developing a signal representative of the instantaneous torque gradient of the torque-time curve through which said fastener system is being tightened base upon said torque and said time signals; and determining the yield point or other predetermined tightened condition on the torque-time curve through which the fastener system is being tightened, responsive to said torque gradient signal, and developing a control signal when said fastener system is tightened to said point.
Claim 10
Dependent Claim
50 words
A method of tightening a fastener system in accordance with claim 7 further comprising: storing a signal representative of the torque gradient of the torque-time curve throughout the tightening region thereof; and developing said control signal when said instantaneous torque gradient signal is a predetermined percentage of said stored signal.
Claim 11
Dependent Claim
27 words
A method of tightening a fastener system in accordance with claim 8 wherein said stored signal is representative of the maximum torque gradient of said torque-time curve.
Claim 12
Dependent Claim
33 words
A method of tightening a fastener system in accordance with claim 9 wherein said control signal is developed when said instantaneous torque gradient signal is approximately 2/3 of said maximum torque gradient signal.
Claim 13
Dependent Claim
37 words
A method of tightening a fastener system in accordance with claim 9 wherein said control signal is developed when said instantaneous torque gradient signal is between approximately 25 to 75 percent of said maximum torque gradient signal.
Claim 14
Dependent Claim
26 words
A method of tightening a fastener system in accordance with claim 1 wherein each of said incremental time signals are developed at equally spaced time intervals.
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) | 1980-05-16 | 1980-11-15 | 1981-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-16 | 1984-11-15 | 1985-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-16 | 1988-11-15 | 1989-05-17 | $7700.00 | Window Closed / Lapsed |