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US4454084A
Expired / Lapsed
US
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Extrusion die control system
Assignee: Crompton and Knowles Corp
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Filing: 1982-06-09
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Granted: 1984-06-12
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Expires: 2002-06-09
Abstract
Abstract The thickness of plastic film extruded from a die is maintained at a desired uniform dimension by utilizing the thermal expansion and contraction of die adjusting bolts to control the width of the orifice of the die. A thickness gauge measures the film thickness across its transverse dimension and provides a signal to a microcomputer which uses the information to calculate the desired die bolt movements. The movements are converted to bolt temperature changes to change the set temperature of each die bolt. A temperature sensing element in the die bolt provides a temperature signal to the microcomputer which controls the amount of power output to each bolt to attain the new set temperature. The temperature sensing and control system provides greater sensitivity, accuracy, and faster response to changing conditions than systems relying only on measurement of thickness variations to control power output to the bolt heaters without using bolt temperature for feedback.
Inventors
- 👤 David J. Smith
- 👤 R. Ted Scharenberg
- 👤 William W. Beck
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 13:36
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/30; B29C48/305; B29C48/31; B29C48/313; B29C48/03; B29C48/07; B29C48/08; B29C48/09; B29C48/10; B29C48/92; B29C2948/00; B29C2948/92; B29C2948/92009; B29C2948/92114; B29C2948/92152; B29C2948/92209; B29C2948/92323; B29C2948/92361; B29C2948/92409; B29C2948/92428; B29C2948/92504; B29C2948/92609; B29C2948/92647; B29C2948/92704; B29C2948/92819; B29C2948/92857; B29C2948/92904
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
230 words
Apparatus for controlling the thickness of plastic film from an extrusion die comprising: a die body having opposing jaw surfaces forming an opening therebetween, one of said jaw surfaces being adjustable with respect to the other to control the width of said opening; a plurality of thermal die adjusting bolts disposed along said one jaw surface, said bolts including electrical heating means for causing said bolts to expand and reduce the width of said opening upon application of increasing electrical power and to contract and widen said opening upon a reduction of said electrical power; thickness measurement and scanning means for measuring the thickness of plastic film passing through said opening and at different transverse locations along said film, said measurement means providing a signal proportional to the thickness of said film; temperature sensing means positioned at each said bolt for sensing the temperature of said bolts and providing a signal proportional to said bolt temperature; means for converting said thickness measurement signal into a temperature reference signal; means for comparing said temperature reference signal with said bolt temperature signal and providing a difference signal; and means for actuating said electrical heating means in accordance with said difference signal to control the temperature of said bolt and cause said bolt temperature signal to reach said reference signal whereby the thickness of said film is maintained at a predetermined uniform dimension.
Claim 2
Dependent Claim
230 words
Apparatus for controlling the thickness of plastic film from an extrusion die comprising: a die body having opposing jaw surfaces forming an opening therebetween, one of said jaw surfaces being adjustable with respect to the other to control the width of said opening; a plurality of thermal die adjusting bolts disposed along said one jaw surface, said bolts including electrical heating means for causing said bolts to expand and reduce the width of said opening upon application of increasing electrical power and to contract and widen said opening upon a reduction of said electrical power; thickness measurement and scanning means for measuring the thickness of plastic film passing through said opening and at different transverse locations along said film, said measurement means providing a signal proportional to the thickness of said film; temperature sensing means positioned at each said bolt for sensing the temperature of said bolts and providing a signal proportional to said bolt temperature; means for converting said thickness measurement signal into a temperature reference signal; means for comparing said temperature reference signal with said bolt temperature signal and providing a difference signal; and means for actuating said electrical heating means in accordance with said difference signal to control the temperature of said bolt and cause said bolt temperature signal to reach said reference signal whereby the thickness of said film is maintained at a predetermined uniform dimension.
Claim 3
Dependent Claim
16 words
The apparatus of claim 1 wherein said bolts are hollow and include an internal electrical heater.
Claim 4
Dependent Claim
18 words
The apparatus of claim 2 wherein said temperature sensing means is a thermocouple positioned within each said bolt.
Claim 5
Dependent Claim
17 words
The apparatus of claim 3 wherein said bolts are threaded or finned externally to provide cooling surfaces.
Claim 6
Dependent Claim
19 words
The apparatus of claim 3 wherein said die opening is longitudinal and said plastic film is a flat sheet.
Claim 7
Dependent Claim
17 words
The apparatus of claim 3 wherein said die opening is annular and said plastic film is tubular.
Claim 8
Dependent Claim
32 words
The apparatus of claim 3 including a microcomputer, said means for converting a thickness measurement into a temperature reference signal and said means for comparing said signals being included in said microcomputer.
Claim 9
Dependent Claim
30 words
The apparatus of claim 1 wherein said actuating means includes means to control the power output to said heating means in each bolt to control the temperature of said bolt.
Claim 10
Dependent Claim
37 words
The apparatus of claim 8 wherein said means to control the power output includes means to control the percentage of time power is supplied to said heating means in each of said bolts during predetermined time intervals.
Claim 11
Independent Claim
155 words
A method for controlling the thickness of plastic film from an extrusion die having opposing jaw surfaces forming an opening therebetween, one jaw surface being adjustable to control the width of the opening, and a plurality of thermal die adjusting bolts including electrical heating means for adjusting the size of said bolts and said opening comprising the steps of: measuring the thickness of plastic film passing through the die opening and providing a signal proportional to the thickness; measuring the temperature of said bolts and providing a signal proportional to the bolt temperature; converting the thickness measurement signal into a temperature reference signal; comparing the temperature reference signal with the bolt temperature signal and providing a difference signal; and controlling the heating of said bolts in accordance with said difference signals to cause said bolt temperature signal to reach said reference signal and maintain the thickness of the plastic film at a predetermined uniform dimension.
Claim 12
Independent Claim
155 words
A method for controlling the thickness of plastic film from an extrusion die having opposing jaw surfaces forming an opening therebetween, one jaw surface being adjustable to control the width of the opening, and a plurality of thermal die adjusting bolts including electrical heating means for adjusting the size of said bolts and said opening comprising the steps of: measuring the thickness of plastic film passing through the die opening and providing a signal proportional to the thickness; measuring the temperature of said bolts and providing a signal proportional to the bolt temperature; converting the thickness measurement signal into a temperature reference signal; comparing the temperature reference signal with the bolt temperature signal and providing a difference signal; and controlling the heating of said bolts in accordance with said difference signals to cause said bolt temperature signal to reach said reference signal and maintain the thickness of the plastic film at a predetermined uniform dimension.
Claim 13
Dependent Claim
34 words
The method of claim 10 wherein the heating of the bolts is controlled by controlling the power output to the heating means in each of the bolts to control the temperature of said bolt.
Claim 14
Dependent Claim
35 words
The method of claim 11 wherein the heating of the bolts is controlled by controlling the percentage of time power is supplied to said heating means in each of said bolts during predetermined time intervals.
References Cited (Backward Citations)
US2938231A
Cited
US3122784A
Cited
US3261893A
Cited
US3307215A
Cited
US3341388A
Cited
US3649726A
Cited
US3751537A
Cited
US3883279A
Cited
US3819775A
Cited
US3920365A
Cited
US3940221A
Cited
US3940221B1
Cited
US4252519A
Cited
US4339403A
Cited
US4281980A
Cited
GB2070290A
Cited
DE3107701A1
Cited
US4272466A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-06-12 | 1987-12-12 | 1988-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-06-12 | 1991-12-12 | 1992-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-06-12 | 1995-12-12 | 1996-06-12 | $7700.00 | Window Closed / Lapsed |