US3782151A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic gauge control system for tandem rolling mill
Assignee: AEG Westinghouse Industrial Automation Corp
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Filing: 1972-02-29
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Granted: 1974-01-01
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Expires: 1992-02-29
Abstract
Abstract An automatic gauge control system for a multi-stand rolling mill of the type wherein output guage is normally controlled by varying tension in the rolled strip material between the last two stands in the mill, this tension between the last two stands being limited between upper and lower maximum values. Due to variations in mill set-up and incoming product variations, the allowable tension range between the last two stands is not sufficient to adequately control thickness. Accordingly, when the tension reference is exceeded in either direction, range control means are provided for simultaneously changing by the same percentage the speeds of the fourth and fifth stands in a fivestand mill, for example, permitting tension to remain constant between the fourth and fifth stands while varying tension between the third and fourth stands to effect a correction in output gauge. The range control means is automatically turned ON when the magnitude of a guage error correction signal indicates that the tension between the last two stands is outside its permissible range. When the tension between the last two stands is again within limits, the range control holds its speed correction signal to the last two stands (i.e., does not apply it to the last two stands) until activated again by an out-of-range tension condition.
Inventors
- 👤 R Peterson
- 👤 J Cook
- 👤 H Bolkey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 11:24
CPC Classifications
B; B21; B21B; B21B37/00; B21B37/48; B21B37/52
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
223 words
A system for controlling the gauge of strip material issuing from a tandem rolling mill wherein an actual output gauge signal is compared with a desired gauge signal to derive a gauge deviation signal used to vary the speed of the last stand in the mill relative to the next to the last stand, and wherein said gauge deviation signal is effective to vary last stand speed only when it falls within predetermined maximum and minimum values; the combination of: deadband range control circuit means to which said gauge deviation signal is applied and which will produce a gauge error correction signal at output terminal means thereof only when said gauge deviation signal falls outside a range of values encompassed within said maximum and minimum values, means for generating a master speed reference signal for controlling the speeds of all stands in said tandem mill, means for multiplying said master speed reference signal by said gauge error correction signal appearing at the output terminal means of said deadband circuit means, and means for combining said master speed reference signal with the output of said multiplying means to derive a signal for simultaneously varying the speeds of said last two stands to maintain tension constant between the last two stands while varying tension between the next to the last stand and its preceding stand.
Claim 2
Independent Claim
223 words
A system for controlling the gauge of strip material issuing from a tandem rolling mill wherein an actual output gauge signal is compared with a desired gauge signal to derive a gauge deviation signal used to vary the speed of the last stand in the mill relative to the next to the last stand, and wherein said gauge deviation signal is effective to vary last stand speed only when it falls within predetermined maximum and minimum values; the combination of: deadband range control circuit means to which said gauge deviation signal is applied and which will produce a gauge error correction signal at output terminal means thereof only when said gauge deviation signal falls outside a range of values encompassed within said maximum and minimum values, means for generating a master speed reference signal for controlling the speeds of all stands in said tandem mill, means for multiplying said master speed reference signal by said gauge error correction signal appearing at the output terminal means of said deadband circuit means, and means for combining said master speed reference signal with the output of said multiplying means to derive a signal for simultaneously varying the speeds of said last two stands to maintain tension constant between the last two stands while varying tension between the next to the last stand and its preceding stand.
Claim 3
Dependent Claim
25 words
The combination of claim 1 including integrating means interposed between said multiplying means and said output terminal means of the deadband range control circuit means.
Claim 4
Dependent Claim
182 words
In the method for controlling the gauge of strip material passing through a tandem rolling mill wherein the final output gauge is normally conTrolled by varying last stand speed to control tension between the last two stands of the mill, the improvement which comprises measuring the gauge of strip material at the output of said tandem mill and comparing it with desired gauge to develop a gauge deviation signal for controlling the speed of the last stand, electrically sensing when the tension between the last two stands is outside a permissible range of tension values by comparison of said gauge deviation signal with tension reference signal means, and when the tension is outside said range of tension values periodically and simultaneously adjusting the speeds of the last two stands to maintain the tension between the last two stands essentially constant while varying tension between the next to the last stand and its preceding stand to effect a gauge correction until comparison of said gauge deviation signal with said reference signal means indicates that tension is again within said range of tension values.
Claim 5
Dependent Claim
182 words
In the method for controlling the gauge of strip material passing through a tandem rolling mill wherein the final output gauge is normally conTrolled by varying last stand speed to control tension between the last two stands of the mill, the improvement which comprises measuring the gauge of strip material at the output of said tandem mill and comparing it with desired gauge to develop a gauge deviation signal for controlling the speed of the last stand, electrically sensing when the tension between the last two stands is outside a permissible range of tension values by comparison of said gauge deviation signal with tension reference signal means, and when the tension is outside said range of tension values periodically and simultaneously adjusting the speeds of the last two stands to maintain the tension between the last two stands essentially constant while varying tension between the next to the last stand and its preceding stand to effect a gauge correction until comparison of said gauge deviation signal with said reference signal means indicates that tension is again within said range of tension values.
Claim 6
Dependent Claim
31 words
The method of claim 3 wherein the speeds of said last two stands are varied by the same percentage value when the tension is outside said permissible range of tension values.
Claim 7
Dependent Claim
90 words
The method of claim 4 including the steps of producing an electrical signal proportional to the actual gauge of strip material issuing from said tandem mill, producing an electrical signal proportional to desired output gauge, comparing said signals to derive said gauge deviation signal for controlling the speed of said last stand relative to the next to the last stand, and limiting said gauge deviation signal between predetermined minimum and maximum tension values, said range of tension values being a median range of values between said minimum and maximum values.
Claim 8
Dependent Claim
24 words
The method of claim 5 wherein said range of tension values is about + or - 60 percent of said maximum and minimum values.
Claim 9
Dependent Claim
82 words
The method of claim 3 wherein the speeds of the last two stands are increased or decreased simultaneously for a period of time until the strip material from the next to the last stand has traveled to a point of gauge measurement at the output of said tandem mill, whereupon the output gauge is again controlled by controlling the speed of said last stand if the tension between the last two stands is no longer outside said permissible range of tension values.
Claim 10
Dependent Claim
41 words
The method of claim 7 wherein the step of adjusting the speeds of said last two stands simultaneously is repeated if the tension between the last two stands is outside said permissible range of values after a gauge measurement is made.
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) | 1976-12-31 | 1977-07-02 | 1978-01-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-31 | 1981-07-02 | 1982-01-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-31 | 1985-07-02 | 1986-01-01 | $7700.00 | Window Closed / Lapsed |