Patent US4722820A successfully refreshed from Google Patents.
US4722820A
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Molten theromplastic web feeding process
Assignee: HITEK Corp Ltd
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Filing: 1984-11-07
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Granted: 1988-02-02
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Expires: 2004-11-07
Abstract
Abstract PCT No. PCT/AU84/00227 Sec. 371 Date Jul. 8, 1985 Sec. 102(e) Date Jul. 8, 1985 PCT Filed Nov. 7, 1984 PCT Pub. No. WO85/02142 PCT Pub. Date May 23, 1985.A web of molten thermoplastics material (4) from extruder die (3) is fed through a pair of temperature controlled rolls (5) having a gap (13) of width less than that of the web thickness leaving the extruder die (3) and is fed from the rolls (5) directly and continuously under uniform tension to a thermoforming machine (9) (10) as a formable web (6) of substantially uniform temperature through its thickness.
Inventors
- 👤 Anthony E. Flecknoe-Brown
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 03:34
CPC Classifications
B; B29; B29C; B29C69/00; B29C69/02; B29C31/00; B29C31/004; B29C43/00; B29C43/22; B29C43/24; B29C48/00; B29C48/03; B29C48/07; B29C48/08; B29C48/13; B29C51/00; B29C51/02; B29C51/18; B29C51/20; B29C51/22; B29C48/001; B29C48/0011; B29C48/0017; Y; Y10; Y10S; Y10S264/00; Y10S264/90; Y10S264/901; Y10S264/902
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
153 words
A method of continuously thermoforming thermoplastic material wherein a web of said material issuing molten from an extruder is passed through a set of temperature controlled rolls and from there to a continuous thermoforming machine the improvement comprising: setting 2 rolls with a gap between them of predetermined uniform width less than the thickness of the web leaving the extruder so that a bank of thermoplastic material is formed before the gap said material leaving the rolls in a hot fluid condition; feeding, directly and continuously the material to the thermoforming machine as a formable web having a substantially uniform temperature through its thickness, the web of material between the rolls and the thermoforming machine being supported under uniform tension by imparting a constant extension to the material from a differential between the speed of the rolls and the speed of a plurality of moving moulds carrying the web through the thermoforming machine.
Claim 2
Independent Claim
153 words
A method of continuously thermoforming thermoplastic material wherein a web of said material issuing molten from an extruder is passed through a set of temperature controlled rolls and from there to a continuous thermoforming machine the improvement comprising: setting 2 rolls with a gap between them of predetermined uniform width less than the thickness of the web leaving the extruder so that a bank of thermoplastic material is formed before the gap said material leaving the rolls in a hot fluid condition; feeding, directly and continuously the material to the thermoforming machine as a formable web having a substantially uniform temperature through its thickness, the web of material between the rolls and the thermoforming machine being supported under uniform tension by imparting a constant extension to the material from a differential between the speed of the rolls and the speed of a plurality of moving moulds carrying the web through the thermoforming machine.
Claim 3
Dependent Claim
28 words
A method as claimed in claim 1 wherein the bank of material is formed of sufficient volume to enable continuous mixing movement of the material forming the bank.
Claim 4
Dependent Claim
31 words
A method as claimed in claim 1 wherein the bank of material is formed of such volume that the material forming the bank is passed through the bank without substantial mixing.
Claim 5
Dependent Claim
23 words
A method as claimed in claim 1 wherein the temperature of the formable web is above the melting point of the thermoplastic material.
Claim 6
Dependent Claim
31 words
A method as claimed in claim 1 wherein the temperature of the web entering the thermoforming machine is not more than 30° C. above the melting point of the thermoplastic material.
Claim 7
Dependent Claim
54 words
A method as claimed in claim 1 wherein the temperature of the web entering the thermoforming machine is controlled so that crystallization has commenced but the percentage crystallinity of the material at this point is less than about 10%, and the web is formed and heat-set in heated forming moulds to form oven-proof containers.
Claim 8
Dependent Claim
14 words
A method as claimed in claim 6 wherein the material is a polyalkylene terephthalate.
Claim 9
Dependent Claim
23 words
A method, as in claim 1 wherein maintaining said bank of material behind the gap serves to both cool and gauge the web.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-02-01 | 1991-08-03 | 1992-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-02-01 | 1995-08-03 | 1996-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-02-01 | 1999-08-03 | 2000-02-02 | $7700.00 | Window Closed / Lapsed |