Patent US3940221A successfully refreshed from Google Patents.
US3940221A
Expired / Lapsed
US
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Thickness control system for an extrusion die
Assignee: Welex Inc
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Filing: 1973-09-10
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Granted: 1976-02-24
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Expires: 1993-09-10
Abstract
Abstract A die having a controllable lip opening, through which flowable material is forced to form a sheet, film or tube. Lip opening control means including an elongated member which expands and contracts thermally and adjusts the lip opening to control the product thickness, and heating means is provided for controlling this expansion and contraction.
Inventors
- 👤 Frank R. Nissel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 22:07
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; B29C48/255; B29C48/2556; B29C48/92; B29C2948/00; B29C2948/92; B29C2948/92009; B29C2948/92114; B29C2948/92152; B29C2948/92504; B29C2948/92609; B29C2948/92647; B29C2948/92704; B29C2948/92819; B29C2948/92857; B29C2948/92904
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
222 words
In an extrusion die for continuously producing a sheet of material that has a substantial width in comparison to its thickness, the combination which comprises: means forming a slit which extends along the width of said die, said slit having an opening of variable thickness, means continuously forcing said material through said slit to form said sheet, slit opening control means including a plurality of spaced-apart elongated members each having capacity to expand and contract thermally, and each operatively arranged to adjust the slit opening at an individual location to control the sheet thickness at said location, a plurality of individual cooling means each connected and structurally located in heat exchange relationship with one of said elongated members upstream of said slit opening for positively cooling said elongated member, and a plurality of individual heating means also connected and structurally located in heat exchange relationship with each said elongated member to heat each said elongated member, means for individually alternately actuating and deactivating said heating means, said heating means having capacity to overcome the cooling of said cooling means on the elongated member with which they are associated, insulating means interposed between said die and both said heating and cooling means, such that the functions of said elongated members and the remainder of the die are substantially thermally independent of each other.
Claim 2
Dependent Claim
222 words
In an extrusion die for continuously producing a sheet of material that has a substantial width in comparison to its thickness, the combination which comprises: means forming a slit which extends along the width of said die, said slit having an opening of variable thickness, means continuously forcing said material through said slit to form said sheet, slit opening control means including a plurality of spaced-apart elongated members each having capacity to expand and contract thermally, and each operatively arranged to adjust the slit opening at an individual location to control the sheet thickness at said location, a plurality of individual cooling means each connected and structurally located in heat exchange relationship with one of said elongated members upstream of said slit opening for positively cooling said elongated member, and a plurality of individual heating means also connected and structurally located in heat exchange relationship with each said elongated member to heat each said elongated member, means for individually alternately actuating and deactivating said heating means, said heating means having capacity to overcome the cooling of said cooling means on the elongated member with which they are associated, insulating means interposed between said die and both said heating and cooling means, such that the functions of said elongated members and the remainder of the die are substantially thermally independent of each other.
Claim 3
Dependent Claim
44 words
The die defined in claim 1, wherein the cooling means includes a continuous stream of air, and means for flowing said air along and in heat exchange relationship with said elongated member in a manner to cool and to contract said elongated member lengthwise.
Claim 4
Dependent Claim
60 words
The die defined in claim 1 wherein a plurality of said slit opening control means are in the form of elongated metal rods provided at spaced apart locations along said slit, and wherein a separate unit of said heating means and a separate unit of said cooling means is arranged in heat conducting relationship with each of said elongated members.
Claim 5
Dependent Claim
60 words
The die defined in claim 1 wherein said slit includes a portion which is bendable under the influence of mechanical force, and wherein said lip opening control means includes an elongated metal member which is physically connected to apply such a bending force under the influence of sufficient heat and cooling to cause thermal expansion and contraction of said metal.
Claim 6
Dependent Claim
52 words
The die defined in claim 1 wherein a plurality of heater blocks are provided through which a plurality of said elongated metal members extend, each said heater block being in heat exchanging relationship with a corresponding one of said elongated metal members to provide heat to further elongate said elongated metal member.
Claim 7
Dependent Claim
23 words
The die defined in claim 5 wherein means are provided for selectively heating said heater block to selectively elongate said elongated metal member.
Claim 8
Dependent Claim
21 words
The die defined in claim 6 wherein said cooling means are constructed and arranged for contact cooling with said heater block.
Claim 9
Dependent Claim
23 words
The die defined in claim 1 wherein said cooling means is continuous but said heating means is connected to operate selectively and intermittently.
Claim 10
Dependent Claim
36 words
The die defined in claim 5 wherein said heater block has three substantially parallel elongated bores, one containing said elongated metal member, another containing a heater plug, and the other providing a passage for cooling air.
Claim 11
Dependent Claim
44 words
The die defined in claim 1 wherein scanning means are provided for sensing the thickness of said sheet at a given location along said lip, and wherein automatic means is connected to control said lip opening control means in response to said scanning means.
Claim 12
Dependent Claim
51 words
The die defined in claim 10 wherein a plurality of said lip opening control means are provided at predetermined stations located along said lip, and wherein said scanning means are arranged to sense said sheet thickness at each of said stations and to control said control means at each corresponding station.
Claim 13
Dependent Claim
25 words
The die defined in claim 1 wherein thickness measuring means is positioned downstream of said slit and in line with said slit opening control means.
Claim 14
Dependent Claim
15 words
The die defined in claim 12, wherein said measuring means includes a thickness indicating means.
Claim 15
Dependent Claim
25 words
The die defined in claim 10, wherein said scanning means includes an emitter and a receiver of rays which are transmitted partially through said sheet.
Claim 16
Dependent Claim
11 words
The die defined in claim 14 wherein said rays are beta-rays.
Claim 17
Dependent Claim
58 words
The die defined in claim 14 wherein automatic control means is provided at a multiplicity of stations spaced apart from one another across the width of said sheet, and where said scanner includes means for determining relative thickness of said sheet at each of said stations and for providing indicia representing such thickness at each of said stations.
Claim 18
Dependent Claim
37 words
The die defined in claim 16 wherein said automatic control means is also operative to introduce heat controllably into each of a multiplicity of heaters located in said lip opening control means at each of said stations.
Claim 19
Dependent Claim
59 words
The die defined in claim 10, wherein said scanning means includes a pair of parallel trackways extending across said sheet, one above and the other below, and wherein means are provided for moving an emitter and a receiver of sheet-penetrating rays in synchronization back and forth across said sheet to measure the thickness of said sheet at prescribed intervals.
Claim 20
Dependent Claim
16 words
The die defined in claim 1, wherein a controllable weir is provided upstream of said lip.
Claim 21
Dependent Claim
23 words
The die defined in claim 19 wherein a plurality of said weirs are provided, spaced apart from one another across said sheet extruder.
Claim 22
Dependent Claim
18 words
The die defined in claim 1 wherein insulating means is provided between said heating means and said lip.
Claim 23
Dependent Claim
24 words
The die defined in claim 1, wherein thermal insulating means includes a layer of insulating material interposed between said die and said cooling means.
Claim 24
Dependent Claim
24 words
The die defined in claim 1, wherein thermal insulating means includes a layer of insulating material interposed between said die and said heating means.
Claim 25
Dependent Claim
27 words
The die defined in claim 1, wherein thermal insulating means includes a layer of insulating material interposed between said die and said both heating and cooling means.
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) | 1979-02-23 | 1979-08-25 | 1980-02-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-02-23 | 1983-08-25 | 1984-02-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-02-23 | 1987-08-25 | 1988-02-24 | $7700.00 | Window Closed / Lapsed |