Patent US3974883A successfully refreshed from Google Patents.
US3974883A
Expired / Lapsed
US
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Tightening system
Assignee: SPS Technologies LLC
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Filing: 1975-05-19
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Granted: 1976-08-17
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Expires: 1995-05-19
Abstract
Abstract The invention disclosed herein relates to a tightening system including a wrench for applying torque and imparting rotation to a fastener system. Associated with the wrench is a control system including measuring systems for developing a first signal representative of the torque applied to the fastener being tightened and a second signal representative of the rotation of the fastener, both of which are fed to a gradient calculating system for developing a signal representative of the slope of a Torque-Rotation curve which can be plotted for the particular fastener being tightened. The gradient signal is used to develop a signal representative of a theoretical curve which is processed with one of the previously developed signals to develop a control signal when the fastener has been tightened to its yield point or some similarly significant point. In one embodiment of the invention, the theoretical curve signal is representative of a curve which ultimately becomes parallel to the linear portion of the Torque-Rotation curve and whose linearity is maintained when the Torque-Rotation curve deviates. The difference between the theoretical torque signal and the instantaneous torque signal, which is referred to as a decision-making signal, is determined and the difference between successive decision-making signals over a fixed increment of rotation is compared to the maximum gradient of the Torque-Rotation curve in its linear region. When the compared signals have a predetermined relationship, the control signal is developed. In another embodiment of the invention, the theoretical curve signal is representative of a curve superimposed on the Torque-Rotation curve through its linear region and whose linearity is maintained when the Torque-Rotation curve deviates. A ratio of the instantaneous torque signal to the theoretical torque signal is determined, and when this ratio is approximately equal to a predetermined ratio, the control signal is developed. In yet another embodiment of the invention, the theoretical curve signal is representative of a curve offset from the Torque-Rotation curve through its linear region by a predetermined constant and whose linearity is also maintained when the Torque-Rotation curve deviates. The theoretical torque signal is compared to the instantaneous torque signal and when the compared signals are approximately equal, the control signal is developed.
Inventors
- 👤 Jerry A. Sigmund
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:52
CPC Classifications
B; B25; B25B; B25B23/00; B25B23/14; G; G05; G05D; G05D17/00; G05D17/02
Claims Analysis
Total Claims: 54
Claim 1
Independent Claim
157 words
A tightening system for tightening a fastener system until a yield point has been detected, said tightening system comprising: wrench means for applying torque and imparting rotation to a fastener; measuring means associated with said wrench means for developing a signal representative of the torque being applied to the fastener and for developing a signal representative of the rotation of the fastener; gradient calculating means responsive to said torque and rotation signals for developing a gradient signal representative of the slope of a Torque-Rotation curve which could be plotted for the fastener being tightened; calculator means for developing a signal representative of a theroetical curve having a predetermined relationship with said Torque-Rotation curve; and control means responsive to said theoretical curve signal and one of said other signals for developing and a control signal when theoretical curve signal and one of said other signals have a predetermined relationship representative of the yield point of the fastener system.
Claim 2
Dependent Claim
157 words
A tightening system for tightening a fastener system until a yield point has been detected, said tightening system comprising: wrench means for applying torque and imparting rotation to a fastener; measuring means associated with said wrench means for developing a signal representative of the torque being applied to the fastener and for developing a signal representative of the rotation of the fastener; gradient calculating means responsive to said torque and rotation signals for developing a gradient signal representative of the slope of a Torque-Rotation curve which could be plotted for the fastener being tightened; calculator means for developing a signal representative of a theroetical curve having a predetermined relationship with said Torque-Rotation curve; and control means responsive to said theoretical curve signal and one of said other signals for developing and a control signal when theoretical curve signal and one of said other signals have a predetermined relationship representative of the yield point of the fastener system.
Claim 3
Dependent Claim
54 words
A tightening system in accordance with claim 1 wherein said Torque-Rotation curve has a linear and non-linear region, and a wherein said calculator means develops a signal representative of a theoretical curve superimposed on the linear region of the Torque-Rotation curve, said theoretical curve remaining linear in the non-linear region of the Torque-Rotation curve.
Claim 4
Dependent Claim
23 words
A tigthening system in accordance with claim 2 wherein said torque signal is subtracted with said theoretical curve signal providing a decision-making signal.
Claim 5
Dependent Claim
41 words
A tigthening system in accordance with claim 3 wherein the difference between successive decision-making signals over a fixed increment of rotation is compared to the gradient signal and a control signal is developed when said compared signals have a predetermined relationship.
Claim 6
Dependent Claim
65 words
A tightening system in accordance with claim 3 wherein said control means includes means for determining the difference between successive ones of said decision-making signals over a fixed increment of rotation and means for comparing said difference to the gradient signal developed in the linear region of said Torque-Rotation curve, said control means developing said control signal when said compared signals have a predetermined relationship.
Claim 7
Dependent Claim
21 words
A tightening system in accordance with claim 5 wherein said control signal is developed when said compared signals are approximately equal.
Claim 8
Dependent Claim
43 words
A tightening system in accordance with claim 5 wherein said control signal is developed when said difference between successive ones of said decision-making signals over a fixed increment of rotation is at least about 40% but less than 100% of said gradient signal.
Claim 9
Dependent Claim
57 words
A tightening system in accordance with claim 1 wherein said Torque-Rotation curve has a linear and a non-linear region, and wherein said calculator means develops a signal representative of a theoretical curve parallel to and offset from the linear region of said Torque-Rotation curve, said theoretical curve remaining linear in the non-linear region of said Torque-Rotation curve.
Claim 10
Dependent Claim
34 words
A tightening system in accordance with claim 8 wherein said theoretical curve signal is compared to said torque signal and wherein said control signal is developed when said compared signals have a predetermined relationship.
Claim 11
Dependent Claim
21 words
A tightening system in accordance with claim 9 wherein said control signal is developed when said compared signals are approximately equal.
Claim 12
Dependent Claim
45 words
A tightening system in accordance with claim 8 wherein said theoretical curve is offset from said Torque-Rotation curve by a predetermined constant such that in the linear region of the Torque-Rotation curve, the theoretical torque is between about 80% to 98% of the actual torque.
Claim 13
Dependent Claim
29 words
A tightening system in accordance with claim 2 wherein a ratio based upon said actual torque signal and said theoretical curve signal is calculated providing a decision making signal.
Claim 14
Dependent Claim
45 words
A tightening system in accordance with claim 12 wherein said decision-making signal is compared to a signal representative of a predetermined relationship between said actual torque signal and said theoretical curve signal, and a control signal is developed when said compared signals are approximately equal.
Claim 15
Dependent Claim
22 words
A tightening system in accordance with claim 13 wherein said signal representative of a predetermined relationship is between about 0.70 to 0.95.
Claim 16
Dependent Claim
28 words
A tightening system in accordance with claim 2 wherein a ratio based upon said actual rotation signal and said theoretical curve signal is calculated providing a decision-making signal.
Claim 17
Dependent Claim
45 words
A tightening system in accordance with claim 15 wherein said decision-making signal is compared to a signal representative of a predetermined relationship between said actual rotation signal and said theoretical curve signal, and a control signal is developed when said compared signals are approximately equal.
Claim 18
Dependent Claim
22 words
A tightening system in accordance with claim 16 wherein said signal representative of a predetermined relationship is between about 0.70 to 0.95.
Claim 19
Dependent Claim
19 words
A tightening system in accordance with claim 1 wherein said control signal is operative to shut off the wrench.
Claim 20
Dependent Claim
25 words
A tightening system in accordance with claim 1 including means for activating said calculator means after a predetermined torque value is applied to the fastener.
Claim 21
Dependent Claim
45 words
A tightening system in accordance with claim 1 wherein said Torque-Rotation curve has a linear and a non-linear region, and wherein said calculator means develops a signal representative of a theoretical curve, a portion thereof being parallel to the linear region of the Torque-Rotation curve.
Claim 22
Dependent Claim
23 words
A tightening system in accordance with claim 20 wherein said torque signal is subtracted from said theoretical curve signal providing a decision-making signal.
Claim 23
Dependent Claim
44 words
A tightening system in accordance with claim 21 wherein the difference between successive ones of said decision-making signals over a fixed increment of rotation is compared to the gradient signal and a control signal is developed when said compared signals have a predetermined relationship.
Claim 24
Dependent Claim
65 words
A tightening system in accordance with claim 21 wherein said control means includes means for determining the difference between successive ones of said decision-making signals over a fixed increment of rotation and means for comparing said difference to the gradient signal developed in the linear region of said Torque-Rotation curve, said control means developing said control signal when said compared signals have a predetermined relationship.
Claim 25
Dependent Claim
21 words
A tightening system in accordance with claim 23 wherein said control signal is developed when said compared signals are approximately equal.
Claim 26
Dependent Claim
43 words
A tightening system in accordance with claim 23 wherein said control signal is developed when said difference between successive ones of said decision-making signals over a fixed increment of rotation is at least about 40% but less than 100% of said gradient signal.
Claim 27
Dependent Claim
135 words
A tightening system for tightening a fastener system until a significant point in the tightening cycle has been detected, said tightening system comprising: a wrench for tightening a fastener; measuring means associated with said wrench for developing signals representative of two fastener system characteristics related such that a curve plotted for the characteristics includes a linear tightening region and a non-linear region; gradient calculating means responsive to said signals for developing a gradient signal representative of the slope of said curve; calculator means for developing a signal representative of a theoretical curve having a predetermined relationship with said curve; and control means responsive to said theoretical curve signal and one of said other signals for developing a control signal when said signals have a predetermined relationship representative of the significant point of the fastener system.
Claim 28
Dependent Claim
135 words
A tightening system for tightening a fastener system until a significant point in the tightening cycle has been detected, said tightening system comprising: a wrench for tightening a fastener; measuring means associated with said wrench for developing signals representative of two fastener system characteristics related such that a curve plotted for the characteristics includes a linear tightening region and a non-linear region; gradient calculating means responsive to said signals for developing a gradient signal representative of the slope of said curve; calculator means for developing a signal representative of a theoretical curve having a predetermined relationship with said curve; and control means responsive to said theoretical curve signal and one of said other signals for developing a control signal when said signals have a predetermined relationship representative of the significant point of the fastener system.
Claim 29
Independent Claim
114 words
A method of tightening a fastener system until a yield point has been detected comprising the steps of: applying torque and imparting rotation to a fastener; measuring a signal representative of the torque being applied to the fastener; measuring a signal representative of the rotation of the fastener; calculating a gradient signal representative of the slope of a Torque-Rotation curve which could be plotted for the fastener being tightened; producing a signal representative of a theoretical curve having a predetermined relationship with said Torque-Rotation curve; and developing a control signal when said theoretical curve signal and one of said other signals have a predetermined relationship representative of the yield point of the fastener system.
Claim 30
Independent Claim
114 words
A method of tightening a fastener system until a yield point has been detected comprising the steps of: applying torque and imparting rotation to a fastener; measuring a signal representative of the torque being applied to the fastener; measuring a signal representative of the rotation of the fastener; calculating a gradient signal representative of the slope of a Torque-Rotation curve which could be plotted for the fastener being tightened; producing a signal representative of a theoretical curve having a predetermined relationship with said Torque-Rotation curve; and developing a control signal when said theoretical curve signal and one of said other signals have a predetermined relationship representative of the yield point of the fastener system.
Claim 31
Dependent Claim
59 words
A method of tightening a fastener system in accordance with claim 27 wherein said Torque-Rotation curve has a linear and a non-linear region, and further comprising the step of developing a signal representative of a theoretical curve superimposed on the linear region of the Torque-Rotation curve, said theoretical curve remaining linear in the non-linear region of the Torque-Rotation curve.
Claim 32
Dependent Claim
27 words
A method of tightening a fastener region in accordance with claim 28 wherein said torque signal is subtracted from said theoretical curve signal providing a decision-making signal.
Claim 33
Dependent Claim
45 words
A method of tightening a fastener system in accordance with claim 29 wherein the difference between successive decision-making signals over a fixed increment of rotation is compared to the gradient signal and a control signal is developed when said compared signals have a predetermined relationship.
Claim 34
Dependent Claim
60 words
A method of tightening a fastener system in accordance with claim 29 further comprising determining the difference between successive ones of said decision-making signals over a fixed increment of rotation and comparing said difference to the gradient signal developed in the linear region of said Torque-Rotation curve, and developing said control signal when said compared signals have a predetermined relationship.
Claim 35
Dependent Claim
25 words
A method of tightening a fastener system in accordance with claim 31 wherein said control signal is developed when said compared signals are approximately equal.
Claim 36
Dependent Claim
47 words
A method of tightening a fastener system in accordance with claim 31 wherein said control signal is developed when said difference between successive ones of said decision-making signals over a fixed increment of rotation is at least about 40% but less than 100% of said gradient signal.
Claim 37
Dependent Claim
59 words
A method of tightening a fastener system in accordance with claim 27 wherein said Torque-Rotation curve has a linear and a non-linear region, and further comprising developing a signal representative of a theoretical curve parallel to and offset from the linear region of said Torque-Rotation curve, said theoretical curve remaining linear in the non-linear region of said Torque-Rotation curve.
Claim 38
Dependent Claim
38 words
A method of tightening a fastener system in accordance with claim 34 wherein said theoretical curve signal is compared to said torque signal and wherein said control signal is developed when said compared signals have a predetermined relationship.
Claim 39
Dependent Claim
25 words
A method of tightening a fastener system in accordance with claim 35 wherein said control signal is developed when said compared signals are approximately equal.
Claim 40
Dependent Claim
49 words
A method of tightening a fastener system in accordance with claim 34 wherein said theoretical curve is offset from said Torque-Rotation curve by a predetermined constant such that in the linear region of the Torque-Rotation curve, the theoretical torque is between about 80% to 98% of the actual torque.
Claim 41
Dependent Claim
32 words
A method of tightening a fastener system in accordance with claim 28 wherein a ratio based upon said actual torque signal and said theoretical curve signal is calculated providing a decision-making signal.
Claim 42
Dependent Claim
49 words
A method of tightening a fastener system in accordance with claim 38 wherein said decision-making signal is compared to a signal representative of a predetermined relationship between said actual torque signal and said theoretical curve signal, and a control signal is developed when said compared signals are approximately equal.
Claim 43
Dependent Claim
26 words
A method of tightening a fastener system in accordance with claim 39 wherein said signal representative of a predetermined relationship is between about 0.70 to 0.95.
Claim 44
Dependent Claim
32 words
A method of tightening a fastener system in accordance with claim 28 whereinn a ratio based upon said actual rotation signal and said theoretical curve signal is calculated providing a decision-making signal.
Claim 45
Dependent Claim
49 words
A method of tightening a fastener system in accordance with claim 41 wherein said decision-making signal is compared to a signal representative of a predetermined relationship between said actual rotation signal and said theoretical curve signal, and a contorl signal is developed when said compared signals are approximately equal.
Claim 46
Dependent Claim
26 words
A method of tightening a fastener system in accordance with claim 42 wherein said signal representative of a predetermined relationship is between about 0.70 to 0.95.
Claim 47
Dependent Claim
50 words
A method of tightening a fastener system in accordance with claim 27 wherein said Torque-Rotation curve has a linear and a non-linear region, and further comprising the step of developing a signal representative of a theoretical curve, a portion thereof being parallel to the linear region of the Torque-Rotation curve.
Claim 48
Dependent Claim
27 words
A method of tightening a fastener system in accordance with claim 44 wherein said torque signal is subtracted from said theoretical curve signal providing a decision-making signal.
Claim 49
Dependent Claim
48 words
A method of tightening a fastener system in accordance with claim 45 wherein the difference between successive ones of said decision-making signals over a fixed increment of rotation is compared to the gradient signal and a control signal is developed when said compared signals have a predetermined relationship.
Claim 50
Dependent Claim
60 words
A method of tightening a fastener system in accordance with claim 45 further comprising determining the difference between successive ones of said decision-making signals over a fixed increment of rotation and comparing said difference to the gradient signal developed in the linear region of said Torque-Rotation curve, and developing said control signal when said compared signals have a predetermined relationship.
Claim 51
Dependent Claim
25 words
A method of tightening a fastener system in accordance with claim 47 wherein said control signal is developed when said compared signals are approximately equal.
Claim 52
Dependent Claim
47 words
A method of tightening a fastener system in accordance with claim 47 wherein said control signal is developed when said difference between successive ones of said decision-making signals over a fixed increment of rotation is at least about 40% but less than 100% of said gradient signal.
Claim 53
Dependent Claim
23 words
A method of tightening a fastener system in accordance with claim 27 wherein said control signal is operative to shut off the wrench.
Claim 54
Dependent Claim
28 words
A method of tightening a fastener system in accordance with claim 27 further comprising calculating said gradient signal after a predetermined torque value is applied to the fastener.
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) | 1979-08-17 | 1980-02-16 | 1980-08-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-17 | 1984-02-16 | 1984-08-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-17 | 1988-02-16 | 1988-08-17 | $7700.00 | Window Closed / Lapsed |