US4182603A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multilayer tubular extrusion die
Assignee: Crompton and Knowles Corp
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Filing: 1978-03-27
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Granted: 1980-01-08
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Expires: 1998-03-27
Abstract
Abstract A coextrusion die for extruding multilayer thermoplastic material in the form of a tube. The die is of the type known as a spiral mandrel die wherein the die mandrels are provided with helical grooves on their peripheries. At least one spiral mandrel has helical grooves of opposite hand than those of the remaining mandrels.
Inventors
- 👤 Richard R. Knittel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:16
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/36; B29C48/50; B29C48/695; B29C48/70; B29C48/705; B29C48/03; B29C48/09; B29C48/10; B29C48/14; B29C48/147; B29C48/1472; B29C48/16; B29C48/18; B29C48/21; B29C48/30; B29C48/32; B29C48/335; B29C48/336; B29C48/3366; B29C2791/00; B29C2791/004; B29C2791/007
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
123 words
Extrusion die apparatus for coextruding thermoplastic material in the form of a tube by means of the blown film process comprising an annular die body, two or more spiral mandrels each having one or more helical grooves in its periphery concentrically mounted within the die body and forming annular passages between the body and one mandrel and between the mandrels, a source of molten thermoplastic material connected to each annular passage wherein the material is forced through the annular passages and extruded from the die in the form of a multilayered tube, the improvement comprising: the helical groove or grooves of at least one spiral mandrel are of opposite hand than the helical groove or grooves of the remaining spiral mandrel or mandrels.
Claim 2
Dependent Claim
123 words
Extrusion die apparatus for coextruding thermoplastic material in the form of a tube by means of the blown film process comprising an annular die body, two or more spiral mandrels each having one or more helical grooves in its periphery concentrically mounted within the die body and forming annular passages between the body and one mandrel and between the mandrels, a source of molten thermoplastic material connected to each annular passage wherein the material is forced through the annular passages and extruded from the die in the form of a multilayered tube, the improvement comprising: the helical groove or grooves of at least one spiral mandrel are of opposite hand than the helical groove or grooves of the remaining spiral mandrel or mandrels.
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) | 1983-01-07 | 1983-07-09 | 1984-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-01-07 | 1987-07-09 | 1988-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-01-07 | 1991-07-09 | 1992-01-08 | $7700.00 | Window Closed / Lapsed |