US3740983A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic gauge control system for tandem rolling mills
Assignee: AEG Westinghouse Industrial Automation Corp
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Filing: 1972-02-29
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Granted: 1973-06-26
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Expires: 1992-02-29
Abstract
Abstract Method and apparatus for varying the gain of an automatic gauge control loop for tandem rolling mills wherein final output gauge is controlled by varying the speed of the last stand in the tandem mill, while tension is controlled between the last two stands by varying the screwdown setting of the last stand. The gain of the control loop is varied as a function of transport time between the bite of the rolls of the last stand and a thickness gauge positioned beyond the last stand. A gauge deviation signal measured in volts/percent error is multiplied by a last stand speed signal to produce a first error signal and by the square of the last stand speed signal to produce a second error signal. These two error signals are summed. At low speeds, the first error signal is effective to control last stand speed with reduced loop gain. However, at higher speeds, the second error signal becomes effective and increases the gain of the loop. Additionally, since the multipliers used to produce the first and second error signals may be inaccurate at very low speeds, the gauge deviation signal is also summed with the aforesaid two error signals and used to control the system at very low speeds.
Inventors
- 👤 R Peterson
- 👤 J Cook
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 08:47
CPC Classifications
B; B21; B21B; B21B37/00; B21B37/16
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
148 words
In the method for controlling final output gauge of strip material passing through a tandem rolling mill by varying the speed of the last stand in said tandem mill, the steps of: measuring the gauge of strip material issuing from said last stand at a point removed from the last stand and producing a signal proportional to the actual measured gauge, comparing said actual gauge signal with a desired gauge signal to derive a gauge deviation signal for varying the speed of said last stand, modifying said gauge deviation signal as a function of the speed of said last stand to derive a first error signal, modifying said gauge deviation signal as a function of the speed of said last stand to derive a second error signal, and combining said error signals and controlling the speed of said last stand as a function of the combined error signals.
Claim 2
Dependent Claim
148 words
In the method for controlling final output gauge of strip material passing through a tandem rolling mill by varying the speed of the last stand in said tandem mill, the steps of: measuring the gauge of strip material issuing from said last stand at a point removed from the last stand and producing a signal proportional to the actual measured gauge, comparing said actual gauge signal with a desired gauge signal to derive a gauge deviation signal for varying the speed of said last stand, modifying said gauge deviation signal as a function of the speed of said last stand to derive a first error signal, modifying said gauge deviation signal as a function of the speed of said last stand to derive a second error signal, and combining said error signals and controlling the speed of said last stand as a function of the combined error signals.
Claim 3
Dependent Claim
43 words
The method of claim 1 including the step of combining the said first and second error signals and said gauge deviation signal and controlling the speed of said last stand with the combined first and second error signals and the gauge deviation signals.
Claim 4
Dependent Claim
48 words
The method of claim 1 wherein said gauge deviation signal is multiplied by the speed of said last stand to derive the first error signal and said gauge deviation signal is multiplied by the square of the speed of said last stand to derive the second error signal.
Claim 5
Dependent Claim
26 words
The method of claim 3 including the step of varying the screwdown setting of said last stand as the speed of said last stand is varied.
Claim 6
Dependent Claim
154 words
Apparatus for controlling the final output gauge of strip material passing through a tandem rolling mill by varying the speed of the last stand in said tandem mill, comprising an automatic gauge control loop including means for measuring the gauge of strip material issuing from said last stand at a point removed from the last stand and for producing a signal proportional to the actual measured gauge, means for comparing said actual gauge signal with a desired gauge signal to derive a gauge deviation signal for varying the speed of said last stand, a speed regulator for said last stand, and means for modifying said gauge deviation signal and for applying the modified gauge deviation signal to said speed regulator, the gauge deviation signal being modified as a function of the speed of said last stand to vary the gain of said automatic gauge control loop as the speed of said last stand varies.
Claim 7
Dependent Claim
154 words
Apparatus for controlling the final output gauge of strip material passing through a tandem rolling mill by varying the speed of the last stand in said tandem mill, comprising an automatic gauge control loop including means for measuring the gauge of strip material issuing from said last stand at a point removed from the last stand and for producing a signal proportional to the actual measured gauge, means for comparing said actual gauge signal with a desired gauge signal to derive a gauge deviation signal for varying the speed of said last stand, a speed regulator for said last stand, and means for modifying said gauge deviation signal and for applying the modified gauge deviation signal to said speed regulator, the gauge deviation signal being modified as a function of the speed of said last stand to vary the gain of said automatic gauge control loop as the speed of said last stand varies.
Claim 8
Dependent Claim
75 words
The apparatus of claim 5 wherein said means for modifying comprises means for multiplying said gauge deviation signal by the speed of said last stand to derive a first error signal, means for multiplying said gauge deviation signal by the square of the speed of said last stand to derive a second error signal, and means for combining said first and second error signals and for applying the combined error signals to said speed regulator.
Claim 9
Dependent Claim
46 words
The apparatus of claim 6 including means for combining the original gauge deviation signal as derived from said comparing means with said first and second error signals and for applying the combined first and second error signals and the gauge deviation signal to said speed regulator.
Claim 10
Dependent Claim
19 words
The apparatus of claim 6 including an operational amplifier for applying said gauge deviation signal to said multiplying means.
Claim 11
Dependent Claim
66 words
The apparatus of claim 8 including an operational amplifier for applying the combined error signAls to said speed regulator, a feedback path for said last-named operational amplifier having a variable limiter therein, and means responsive to the speed of the said last stand so as to prevent automatic gauge control from causing strip breakage between last two stands of the mill for controlling said variable limiter.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-25 | 1976-12-25 | 1977-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-25 | 1980-12-25 | 1981-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-25 | 1984-12-25 | 1985-06-26 | $7700.00 | Window Closed / Lapsed |