US3906764A
Expired / Lapsed
US
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Rolling mill control method and apparatus
Assignee: Bethlehem Steel Corp
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Filing: 1974-11-08
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Granted: 1975-09-23
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Expires: 1994-11-08
Abstract
Abstract Rolling mill with computer programmed for absolute lock-on AGC control rolls material having absolute aim gage without using an active thickness gage in the control loop. Computer is programmed to calculate; (a) lock-on length of rolled material, (b) mill stretch using a simplified subroutine, (c) calibration-corrected roll gap, (d) a lock-on thickness error relative to aim gage, (e) a corrected roll gap reference signal as a function of a constant lock-on thickness error and other variable thickness errors caused by changes in mill stretch and roll gap occurring after lock-on, and (f) a rate-sensitive variable gain of the corrected roll gap reference signal to reduce thickness errors to substantially zero as rapidly as possible.
Inventors
- 👤 George E Mueller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 11:32
CPC Classifications
B; B21; B21B; B21B37/00; B21B37/16; B21B38/00; B21B38/10; B21B38/105; B21B1/00; B21B1/02; B21B1/06; B21B2271/00; B21B2271/06
Claims Analysis
Total Claims: 50
Claim 1
Independent Claim
153 words
In a method of automatically controlling rolling mill roll gap where a preset roll gap is adjusted in response to a roll gap reference signal, the improvement which comprises: a. establishing a lock-on AGC control mode when the head-end of said material enters the mill rolls, including: 1. storing lock-on values of mill stretch and roll position signals generated during rolling of said material, and 2. thereafter adjusting roll gap to maintain material thickness according to a roll gap reference signal which is produced in response to changes in said mill stretch and roll position signals after lock-on, b. producing a lock-on thickness error signal by comparing an aim gage signal with said stored lock-on values of said mill stretch and roll position signals, and c. correcting the roll gap reference signal by a predetermined amount of the lock-on thickness error signal to cause the production of rolled material having absolute aim gage.
Claim 2
Dependent Claim
153 words
In a method of automatically controlling rolling mill roll gap where a preset roll gap is adjusted in response to a roll gap reference signal, the improvement which comprises: a. establishing a lock-on AGC control mode when the head-end of said material enters the mill rolls, including: 1. storing lock-on values of mill stretch and roll position signals generated during rolling of said material, and 2. thereafter adjusting roll gap to maintain material thickness according to a roll gap reference signal which is produced in response to changes in said mill stretch and roll position signals after lock-on, b. producing a lock-on thickness error signal by comparing an aim gage signal with said stored lock-on values of said mill stretch and roll position signals, and c. correcting the roll gap reference signal by a predetermined amount of the lock-on thickness error signal to cause the production of rolled material having absolute aim gage.
Claim 3
Dependent Claim
87 words
thereafter adjusting roll gap to maintain material thickness according to a roll gap reference signal which is produced in response to changes in said mill stretch and roll position signals after lock-on, b. producing a lock-on thickness error signal by comparing an aim gage signal with said stored lock-on values of said mill stretch and roll position signals, and c. correcting the roll gap reference signal by a predetermined amount of the lock-on thickness error signal to cause the production of rolled material having absolute aim gage.
Claim 4
Dependent Claim
87 words
thereafter adjusting roll gap to maintain material thickness according to a roll gap reference signal which is produced in response to changes in said mill stretch and roll position signals after lock-on, b. producing a lock-on thickness error signal by comparing an aim gage signal with said stored lock-on values of said mill stretch and roll position signals, and c. correcting the roll gap reference signal by a predetermined amount of the lock-on thickness error signal to cause the production of rolled material having absolute aim gage.
Claim 5
Dependent Claim
9 words
The method of claim 1 wherein step (a) includes:
Claim 6
Dependent Claim
37 words
calculating the mill stretch signal prior to lock-on as a function of a predicted roll force signal and a mill spring constant signal, the latter signal determined from plural signal sources representing various sets of operating parameters.
Claim 7
Dependent Claim
37 words
calculating the mill stretch signal prior to lock-on as a function of a predicted roll force signal and a mill spring constant signal, the latter signal determined from plural signal sources representing various sets of operating parameters.
Claim 8
Dependent Claim
20 words
means responsive to said roll force signal for producing a first signal representing a change in mill stretch after lock-on,
Claim 9
Dependent Claim
20 words
means responsive to said roll force signal for producing a first signal representing a change in mill stretch after lock-on,
Claim 10
Dependent Claim
20 words
means responsive to said roll force signal for producing a first signal representing a change in mill stretch after lock-on,
Claim 11
Dependent Claim
20 words
means responsive to said roll force signal for producing a first signal representing a change in mill stretch after lock-on,
Claim 12
Dependent Claim
20 words
means responsive to said roll gap signal for producing a second signal representing a change in roll gap after lock-on,
Claim 13
Dependent Claim
20 words
means responsive to said roll gap signal for producing a second signal representing a change in roll gap after lock-on,
Claim 14
Dependent Claim
20 words
means responsive to said screw position signal for producing a second signal representing a change in screw position after lock-on,
Claim 15
Dependent Claim
20 words
means responsive to said screw position signal for producing a second signal representing a change in screw position after lock-on,
Claim 16
Dependent Claim
39 words
recalculating the mill stretch signal at lock-on as a function of an actual roll force signal and a stored specific mill spring constant signal determined from a specific signal source representing a given set of operating parameters at lock-on.
Claim 17
Dependent Claim
39 words
recalculating the mill stretch signal at lock-on as a function of an actual roll force signal and a stored specific mill spring constant signal determined from a specific signal source representing a given set of operating parameters at lock-on.
Claim 18
Dependent Claim
9 words
The method of claim 1 wherein step (a) includes:
Claim 19
Dependent Claim
24 words
The method of claim 1 wherein the mill stretch signal of step (a) is calculated for each different pass of material through the mill.
Claim 20
Dependent Claim
29 words
means responsive to said aim gage signal and lock-on values of mill stretch and screw position signals for producing a third signal representing a lock-on thickness error function, and
Claim 21
Dependent Claim
29 words
means responsive to said aim gage signal and lock-on values of mill stretch and screw position signals for producing a third signal representing a lock-on thickness error function, and
Claim 22
Dependent Claim
15 words
modifying the roll position signal by a calibration correction signal produced by an external source.
Claim 23
Dependent Claim
15 words
modifying the roll position signal by a calibration correction signal produced by an external source.
Claim 24
Dependent Claim
28 words
means responsive to said aim gage signal lock-on values of mill stretch and roll gap signals for producing a third signal representing a lock-on thickness error function, and
Claim 25
Dependent Claim
28 words
means responsive to said aim gage signal lock-on values of mill stretch and roll gap signals for producing a third signal representing a lock-on thickness error function, and
Claim 26
Dependent Claim
32 words
means responsive to said first, second and third signals for producing a corrected roll gap reference which acts on said adjusting means to cause production of rolled material having absolute aim gage.
Claim 27
Dependent Claim
32 words
means responsive to said first, second and third signals for producing a corrected roll gap reference which acts on said adjusting means to cause production of rolled material having absolute aim gage.
Claim 28
Dependent Claim
22 words
means responsive to said first, second and third signals for producing a corrected roll gap reference which acts on said adjusting means.
Claim 29
Dependent Claim
22 words
means responsive to said first, second and third signals for producing a corrected roll gap reference which acts on said adjusting means.
Claim 30
Dependent Claim
9 words
The method of claim 1 wherein step (a) inclues;
Claim 31
Dependent Claim
26 words
The method of claim 5 wherein the calibration correction signal is produced by detecting changes in one or more stored signals representing predetermined rolling mill properties.
Claim 32
Dependent Claim
61 words
means receiving said means (a) signal, said means d3 second signal, and said means (h) signals for varying the gain of said means d5 corrected roll gap reference signal to vary the speed of roll gap adjustment as a function of one or more of said means (h) signals and the rate of change of said means (a) and d3 signals.
Claim 33
Dependent Claim
61 words
means receiving said means (a) signal, said means d3 second signal, and said means (h) signals for varying the gain of said means d5 corrected roll gap reference signal to vary the speed of roll gap adjustment as a function of one or more of said means (h) signals and the rate of change of said means (a) and d3 signals.
Claim 34
Dependent Claim
40 words
The method of claim 5 wherein The calibration correction signal is produced by detecting and storing a thickness signal derived from a gage devoid of the AGC control loop during one or more previous passes of material through the mill.
Claim 35
Dependent Claim
52 words
The method of claim 1 further including: d. varying the gain of said roll gap reference signal to vary the speed of roll gap adjustment as a function one or more signals representing such parameters as material properties, and rate of change of roll force and roll position signals detected after lock-on.
Claim 36
Independent Claim
157 words
A method of automatically controlling rolling mill roll gap to produce rolled material having absolute aim gage, which method comprises: a. adjusting a screwdown mechanism to vary mill roll gap from an initial preset value to other values in response to a corrected screwdown reference signal, b. establishing a lock-on AGC control mode when the head-end of said material enters the mill rolls, including storing lock-on values of mill stretch and roll position signals generated during rolling of said material, and thereafter adjusting the screwdown mechanism to maintain head-end material thickness according to a screwdown reference signal which is produced in response to changes in said mill stretch and roll position signals after lock-on, c. producing a lock-on thickness error signal by comparing an aim gage signal with said stored lock-on values of said mill stretch and roll position signals, and d. correcting the screwdown reference signal by a predetermined amount of the lock-on thickness error signal.
Claim 37
Independent Claim
157 words
A method of automatically controlling rolling mill roll gap to produce rolled material having absolute aim gage, which method comprises: a. adjusting a screwdown mechanism to vary mill roll gap from an initial preset value to other values in response to a corrected screwdown reference signal, b. establishing a lock-on AGC control mode when the head-end of said material enters the mill rolls, including storing lock-on values of mill stretch and roll position signals generated during rolling of said material, and thereafter adjusting the screwdown mechanism to maintain head-end material thickness according to a screwdown reference signal which is produced in response to changes in said mill stretch and roll position signals after lock-on, c. producing a lock-on thickness error signal by comparing an aim gage signal with said stored lock-on values of said mill stretch and roll position signals, and d. correcting the screwdown reference signal by a predetermined amount of the lock-on thickness error signal.
Claim 38
Dependent Claim
67 words
In apparatus for automatically controlling rolling mill roll gap where a preset roll gap is adjusted by means responsive to a roll gap reference signal, the improvement comprising: a. means for producing a roll force signal, b. means for producing a roll gap signal, c. means for producing an aim gage signal, d. computer means receiving said roll force, roll gap and aim gage signals and including:
Claim 39
Dependent Claim
67 words
In apparatus for automatically controlling rolling mill roll gap where a preset roll gap is adjusted by means responsive to a roll gap reference signal, the improvement comprising: a. means for producing a roll force signal, b. means for producing a roll gap signal, c. means for producing an aim gage signal, d. computer means receiving said roll force, roll gap and aim gage signals and including:
Claim 40
Dependent Claim
45 words
The apparatus of claim 10 including: e. means for generating a lock-on control signal after a predetermined head-end length of material enters the mill rolls and controlling the storage of lock-on values of said mill stretch and roll force signals with said lock-on control signal.
Claim 41
Dependent Claim
30 words
The apparatus of claim 10 including: f. means for producing a predicted roll force signal and plural signals representing various sets of operating parameters, and wherein computer means (d) includes:
Claim 42
Dependent Claim
28 words
The apparatus of claim 10 wherein computer means (d) is programmed by means 1 to calculate mill stretch for each different pass of material through said rolling miLl.
Claim 43
Dependent Claim
31 words
The apparatus of claim 1 including: g. means for producing a calibration correction signal, said signal modifying the roll gap signal in computer means d3 to provide a corrected second signal.
Claim 44
Dependent Claim
24 words
The apparatus of claim 1 including: h. means for producing plural signals of corresponding plural operating parameters, and wherein computer means (d) further includes:
Claim 45
Dependent Claim
84 words
Apparatus for automatically controlling rolling mill roll gap to produce rolled material having absolute aim gage, comprising: a. means including a screwdown mechanism for adjusting mill roll gap from an initial preset value to other values in response to a corrected roll gap reference signal, b. means for producing a roll force signal, c. means for producing a screw position signal, d. means for producing an aim gage signal, e. computer means receiving said roll force, screw position and aim gage signals and including:
Claim 46
Dependent Claim
84 words
Apparatus for automatically controlling rolling mill roll gap to produce rolled material having absolute aim gage, comprising: a. means including a screwdown mechanism for adjusting mill roll gap from an initial preset value to other values in response to a corrected roll gap reference signal, b. means for producing a roll force signal, c. means for producing a screw position signal, d. means for producing an aim gage signal, e. computer means receiving said roll force, screw position and aim gage signals and including:
Claim 47
Dependent Claim
9 words
means for storing a family of mill stretch curves,
Claim 48
Dependent Claim
9 words
means for storing a family of mill stretch curves,
Claim 49
Dependent Claim
87 words
means for storing a specific mill stretch curve, said 1 means programmed for computer means (d) to cause said 21 means to receive said means (f) signals prior to lock-on and to select a specific mill stretch curve in response thereto, and to store said selection in means 22, and said 1 means also programmed for computer means (d) to calculate mill stretch after lock-on as a function of the specific mill stretch curve stored in means 22 and the actual roll force signal of means (a).
Claim 50
Dependent Claim
87 words
means for storing a specific mill stretch curve, said 1 means programmed for computer means (d) to cause said 21 means to receive said means (f) signals prior to lock-on and to select a specific mill stretch curve in response thereto, and to store said selection in means 22, and said 1 means also programmed for computer means (d) to calculate mill stretch after lock-on as a function of the specific mill stretch curve stored in means 22 and the actual roll force signal of means (a).
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) | 1978-09-22 | 1979-03-24 | 1979-09-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-22 | 1983-03-24 | 1983-09-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-22 | 1987-03-24 | 1987-09-23 | $7700.00 | Window Closed / Lapsed |