US3869892A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Feed forward gauge control system for a rolling mill
Assignee: Honeywell Measurex Corp
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Filing: 1974-04-08
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Granted: 1975-03-11
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Expires: 1994-04-08
Abstract
Abstract A control method and apparatus for maintaining a uniform predetermined thickness of rolled sheet metal in a metal rolling mill where variations in sheet thickness are measured prior to its entry into the mill rolls. As a basic function, signals corresponding to the measured variations are fed forward to control pressure actuator means for the rolls, to provide corrections that eliminate the variations. The actuator means are also controlled by a secondary function that operates independently to slowly return the pressure value of the actuator means toward its original pre-set value as corrections are applied in response to measured variations. These two control functions are added together to form a composite change to the roll pressure actuactor means which controls the roll pressure and prevents it from exceeding its original pre-set value by an amount that would disturb the strip ''''shape.'''' The variations of the unrolled sheet thickness are measured accurately even though the pass angle seen by the entry gauge is constantly varying.
Inventors
- 👤 John D Higham
- 👤 Colin J Mcnaught
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 16:31
CPC Classifications
B; B21; B21B; B21B37/00; B21B37/48; B21B37/52; B21B37/54
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
273 words
A method for controlling the gauge without changing the shape of strip material issuing from a rolling mill that includes a payoff reel, a pair of pressure rolls to produce a desired roll force, pressure control means for varying the pressure of said rolls on the strip material and the gap between them, a takeup reel, an input gauge between said payoff reel and said rolls, tension control means for the strip material, an output gauge and feedback means connected to said output gauge, said method comprising the steps of: generating a signal at the input gauge for determining a variation in the gauge of material from the payoff reel from a nominal thickness; producing a primary control function causing said pressure control means to operate in response to the variation in gauge detected by said input gauge when the actual gauge variation reaches said pressure rolls, said primary control function operating on said pressure rolls to change their force on the strip at a relatively rapid rate to substantially eliminate the thickness variation; superimposing a secondary function on said pressure control means immediately after the activation of said primary function, said secondary function causing the changed force of the pressure rolls on the strip material by said primary control function to commence returning at a relatively slow steady rate toward the original preset level and thereby causing a relatively small variation in target gauge of the material passing from said rolls; generating an error signal proportional to said small variation at the exit gauge; and utilizing said error signal to activate a mill control means for eliminating said small variation in gauge.
Claim 2
Independent Claim
273 words
A method for controlling the gauge without changing the shape of strip material issuing from a rolling mill that includes a payoff reel, a pair of pressure rolls to produce a desired roll force, pressure control means for varying the pressure of said rolls on the strip material and the gap between them, a takeup reel, an input gauge between said payoff reel and said rolls, tension control means for the strip material, an output gauge and feedback means connected to said output gauge, said method comprising the steps of: generating a signal at the input gauge for determining a variation in the gauge of material from the payoff reel from a nominal thickness; producing a primary control function causing said pressure control means to operate in response to the variation in gauge detected by said input gauge when the actual gauge variation reaches said pressure rolls, said primary control function operating on said pressure rolls to change their force on the strip at a relatively rapid rate to substantially eliminate the thickness variation; superimposing a secondary function on said pressure control means immediately after the activation of said primary function, said secondary function causing the changed force of the pressure rolls on the strip material by said primary control function to commence returning at a relatively slow steady rate toward the original preset level and thereby causing a relatively small variation in target gauge of the material passing from said rolls; generating an error signal proportional to said small variation at the exit gauge; and utilizing said error signal to activate a mill control means for eliminating said small variation in gauge.
Claim 3
Independent Claim
273 words
A method for controlling the gauge without changing the shape of strip material issuing from a rolling mill that includes a payoff reel, a pair of pressure rolls to produce a desired roll force, pressure control means for varying the pressure of said rolls on the strip material and the gap between them, a takeup reel, an input gauge between said payoff reel and said rolls, tension control means for the strip material, an output gauge and feedback means connected to said output gauge, said method comprising the steps of: generating a signal at the input gauge for determining a variation in the gauge of material from the payoff reel from a nominal thickness; producing a primary control function causing said pressure control means to operate in response to the variation in gauge detected by said input gauge when the actual gauge variation reaches said pressure rolls, said primary control function operating on said pressure rolls to change their force on the strip at a relatively rapid rate to substantially eliminate the thickness variation; superimposing a secondary function on said pressure control means immediately after the activation of said primary function, said secondary function causing the changed force of the pressure rolls on the strip material by said primary control function to commence returning at a relatively slow steady rate toward the original preset level and thereby causing a relatively small variation in target gauge of the material passing from said rolls; generating an error signal proportional to said small variation at the exit gauge; and utilizing said error signal to activate a mill control means for eliminating said small variation in gauge.
Claim 4
Independent Claim
273 words
A method for controlling the gauge without changing the shape of strip material issuing from a rolling mill that includes a payoff reel, a pair of pressure rolls to produce a desired roll force, pressure control means for varying the pressure of said rolls on the strip material and the gap between them, a takeup reel, an input gauge between said payoff reel and said rolls, tension control means for the strip material, an output gauge and feedback means connected to said output gauge, said method comprising the steps of: generating a signal at the input gauge for determining a variation in the gauge of material from the payoff reel from a nominal thickness; producing a primary control function causing said pressure control means to operate in response to the variation in gauge detected by said input gauge when the actual gauge variation reaches said pressure rolls, said primary control function operating on said pressure rolls to change their force on the strip at a relatively rapid rate to substantially eliminate the thickness variation; superimposing a secondary function on said pressure control means immediately after the activation of said primary function, said secondary function causing the changed force of the pressure rolls on the strip material by said primary control function to commence returning at a relatively slow steady rate toward the original preset level and thereby causing a relatively small variation in target gauge of the material passing from said rolls; generating an error signal proportional to said small variation at the exit gauge; and utilizing said error signal to activate a mill control means for eliminating said small variation in gauge.
Claim 5
Dependent Claim
26 words
The method as described in claim 1 wherein said error signal is utilized to operate the tension control means to counteract said small variation in gauge.
Claim 6
Dependent Claim
30 words
The method as described in claim 1 wherein said error signal is utilized to vary the speed of strip material in the mill to counteract said small variation in gauge.
Claim 7
Dependent Claim
71 words
The method as described in claim 1 wherein the signal is generated at the input gauge by measuring the actual thickness of the strip as it passes at a varying angle between the radiation source and detector elements of the entry gauge and using said signal from the input gauge in conjunction with the assumed nominal thickness value of the strip material to compute the actual variation in incoming strip thickness.
Claim 8
Dependent Claim
120 words
The method as described in claim 4 wherein said actual variation in incoming strip thickness is determined by the equation TA - 1/ Mu RM (loge RA/loge RM) Delta RM where: Mu a constant depending on the absorption characteristics of the material being measured; RA is the ratio between the voltage provided by the detector with material present and the voltage with only air present when the metal is perpendicular to the detector''s radiation beam; RM is the ratio between the voltage provided by the detector with material present and the voltage with only air present which is actually measured with the strip at an angle to the radiation beam; Delta RM is the current RM minus the previous RM.
Claim 9
Dependent Claim
200 words
In a rolling mill including a payoff reel for a strip of sheet material connected to a takeup reel, a pair of pressure rolls for applying a forming force on said strip material and a pressure control means for controlling said pressure rolls, an entry gauge between said payoff reel and said rolls and an exit gauge between said rolls and said takeup reel, a feed forward thickness control system for said mill comprising: means for utilizing signals from said entry gauge and comparing them with an input proportional to the assumed nominal thickness of the strip material from said payoff reel to produce signals proportional to variations in thickness of the strip material; primary control means for utilizing said signals proportional to said strip thickness variations for operating said pressure rolls control means to cause a relatively rapid increase in pressure by said rolls; means responsive to activation of said pressure control means for commencing a steady reduction of roll pressure; feedback control means responsive to signals generated by said exit gauge compared with a preselected target gauge for producing an error signal; and means responsive to said error signals for activating another gauge control means on the mill.
Claim 10
Dependent Claim
200 words
In a rolling mill including a payoff reel for a strip of sheet material connected to a takeup reel, a pair of pressure rolls for applying a forming force on said strip material and a pressure control means for controlling said pressure rolls, an entry gauge between said payoff reel and said rolls and an exit gauge between said rolls and said takeup reel, a feed forward thickness control system for said mill comprising: means for utilizing signals from said entry gauge and comparing them with an input proportional to the assumed nominal thickness of the strip material from said payoff reel to produce signals proportional to variations in thickness of the strip material; primary control means for utilizing said signals proportional to said strip thickness variations for operating said pressure rolls control means to cause a relatively rapid increase in pressure by said rolls; means responsive to activation of said pressure control means for commencing a steady reduction of roll pressure; feedback control means responsive to signals generated by said exit gauge compared with a preselected target gauge for producing an error signal; and means responsive to said error signals for activating another gauge control means on the mill.
Claim 11
Dependent Claim
105 words
The method as described in claim 6 wherein said primary control function is produced by: computing the transport time of a gauge variation from the measurement point to the roll bite and subtracting from this time a roll gap time constant; providing a pass angle correction to the nominal entry thickness and using it in conjunction with a calibration constant to convert the delayed change in entry gauge measurement into a thickness change; computing a change in the roll gap based on the previously computed thickness change modified by characteristics of the strip material; and checking the computed roll pressure for compliance with operational limits.
Claim 12
Independent Claim
270 words
An apparatus for controlling the gauge and shape of strip material issuing from a rolling mill that includes a payoff reel, a pair of pressure rolls adjustable to a preselected gap to produce a desired target thickness, pressure control means for varying the pressure of said rolls on the strip material and the gap between them, a takeup reel, an input gauge between said payoff reel and said rolls, tension control means for the strip material, an output gauge and feedback means connected to said output gauge, said apparatus comprising: means for generating a signal at the input gauge for determining a variation in the gauge of material from the payoff reel from a nominal thickness; means responsive to said signal from said input gauge for producing a primary control function causing said pressure control means to operate when the actual gauge variation reaches said pressure rolls to change their force on the strip at a relatively rapid rate to substantially eliminate the thickness variation; means for superimposing a secondary function on said pressure control means immediately after the activation of said primary function, said secondary function causing the changed force of the pressure rolls on the strip material by said primary control function to commence returning at a relatively slow steady rate toward the original preset level and thereby causing a relatively small variation in target gauge oF the material passing from said rolls; means for generating an error signal proportional to said small variation at the exit gauge; and means for utilizing said error signal to activate a mill control means for eliminating said small variation in gauge.
Claim 13
Independent Claim
270 words
An apparatus for controlling the gauge and shape of strip material issuing from a rolling mill that includes a payoff reel, a pair of pressure rolls adjustable to a preselected gap to produce a desired target thickness, pressure control means for varying the pressure of said rolls on the strip material and the gap between them, a takeup reel, an input gauge between said payoff reel and said rolls, tension control means for the strip material, an output gauge and feedback means connected to said output gauge, said apparatus comprising: means for generating a signal at the input gauge for determining a variation in the gauge of material from the payoff reel from a nominal thickness; means responsive to said signal from said input gauge for producing a primary control function causing said pressure control means to operate when the actual gauge variation reaches said pressure rolls to change their force on the strip at a relatively rapid rate to substantially eliminate the thickness variation; means for superimposing a secondary function on said pressure control means immediately after the activation of said primary function, said secondary function causing the changed force of the pressure rolls on the strip material by said primary control function to commence returning at a relatively slow steady rate toward the original preset level and thereby causing a relatively small variation in target gauge oF the material passing from said rolls; means for generating an error signal proportional to said small variation at the exit gauge; and means for utilizing said error signal to activate a mill control means for eliminating said small variation in gauge.
Claim 14
Dependent Claim
27 words
The apparatus as described in claim 8 including means for utilizing said error signal to operate the tension control means to counteract said small variation in gauge.
Claim 15
Dependent Claim
31 words
The apparatus as described in claim 8 including means for utilizing said error signal to vary the speed of strip material in the mill to counteract said small variation in gauge.
Claim 16
Dependent Claim
77 words
The apparatus as described in claim 8 wherein said means for generating a signal at the input gauge includes means for measuring the actual thickness of the strip as it passes at a varying angle between the radiation source and detector elements of the entry gauge and means for using said signal from the input gauge in conjunction with the assumed nominal thickness value of the strip material to compute the actual variation in incoming strip thickness.
References Cited (Backward Citations)
US3194036A
Cited
US3553991A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-10 | 1978-09-09 | 1979-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-10 | 1982-09-09 | 1983-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-10 | 1986-09-09 | 1987-03-11 | $7700.00 | Window Closed / Lapsed |