US3856448A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multi-core circular die for preparing multi-layer tubular film
Assignee: Japan Steel Works Ltd
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Filing: 1972-12-29
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Granted: 1974-12-24
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Expires: 1992-12-29
Abstract
Abstract A multi-core circular die for preparing multi-layer tubular film from thermoplastic resins which includes a plurality of cores having concentric tube portions and central spherical portions which are rotatably fitted with each other along the spherical portions. A plurality of tubular passages are provided for conducting the flow of the molten resins, the passages being formed within spaces formed between the tube portions of the cores, a housing surroundingly securing the cores together. Adjusting bolts are provided within the lower portions of the cores and housing so as to adjust the angles of the cores relative to the axis whereby the thickness of the passages, and consequently the film layers, may be altered so as to achieve film layers of uniform thickness.
Inventors
- 👤 A Iijima
- 👤 Y Yokoyama
- 👤 Y Yamada
- 👤 M Kimura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 06:42
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/03; B29C48/09; B29C48/10; B29C48/16; B29C48/18; B29C48/21; B29C48/25; B29C48/30; B29C48/32; B29C48/335; B29C48/337; B29C48/338; B29C48/34; B29C48/92; B32; B32B; B32B1/00; B32B1/08; B32B27/00; B32B27/06; B32B27/08; B32B27/30; B32B27/306; B32B27/32; B32B7/00; B32B7/04; B32B7/12; B29C2948/00; B29C2948/92; B29C2948/92009; B29C2948/92114; B29C2948/92152; B29C2948/92323; B29C2948/92447; B29C2948/92504; B29C2948/92609; B29C2948/92647; B29C2948/92704; B29C2948/92819; B29C2948/92857; B29C2948/92876; B29C2948/92895
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
101 words
Apparatus for preparing a multi-layer tubular film made of a thermoplastic resin comprising a multi-core circular die which in turn comprises: a plurality of cores having concentric tube portions and central spherical portions which are rotatably fitted with each other at said central spherical portions; a housing surrounding said cores and having a spherical inner surface which rotatably secures said cores together; and a plurality of tubular passages for conducting the flow of said resin which are disposed within spaces formed between said tube portions of said cores and between said tube portions of one of said cores and said housing.
Claim 2
Dependent Claim
101 words
Apparatus for preparing a multi-layer tubular film made of a thermoplastic resin comprising a multi-core circular die which in turn comprises: a plurality of cores having concentric tube portions and central spherical portions which are rotatably fitted with each other at said central spherical portions; a housing surrounding said cores and having a spherical inner surface which rotatably secures said cores together; and a plurality of tubular passages for conducting the flow of said resin which are disposed within spaces formed between said tube portions of said cores and between said tube portions of one of said cores and said housing.
Claim 3
Dependent Claim
44 words
The apparatus as set forth in claim 1, which further comprises a lip having a plurality of branch passages which are respectively connected to each of said tubular passages of said multi-layer circular die, wherein molten resins supplied to said branch passages are coextruded.
Claim 4
Dependent Claim
32 words
The apparatus as set forth in claim 1 which further comprises a mandrel at least partially disposed within the inner most one of said plurality of cores above said multi-layer circular die.
Claim 5
Dependent Claim
50 words
The apparatus as set forth in claim 1, wherein a plurality of adjusting screws are connected to the lower portions of said housing and said cores, whereby the angle of each core relative to the die axis may be adjusted so as to provide said tubular passages of uniform thickness.
Claim 6
Dependent Claim
42 words
The apparatus as set forth in claim 1, wherein heating means are disposed upon an outer surface of said housing and upon an inner surface of one of said cores so as to control the temperature of each of the molten resins.
Claim 7
Dependent Claim
44 words
The apparatus as set forth in claim 2, wherein said branch passages are disposed between tubular portions of said lip, each tubular portion of said lip being engaged to a corresponding head portion of said cores and said housing of said multi-layer circular die.
Claim 8
Dependent Claim
53 words
The apparatus as set forth in claim 2, wherein an outer branch passage is formed in a direction parallel to the die axis while the other inner branch passages are formed in a direction which diverges from said axis and wherein further, all of said branch passages are joined at an outlet position.
Claim 9
Dependent Claim
32 words
The apparatus as set forth in claim 2, wherein all of said branch passages are formed in a direction which diverges from the die axis and are joined at an outlet position.
Claim 10
Dependent Claim
53 words
The apparatus as set forth in claim 2, wherein an inner branch passage is formed in a direction parallel to the die axis while the other outer branch passages are formed in a direction which converges toward said axis, and wherein further, all of said branch passages are joined at an outlet position.
Claim 11
Dependent Claim
31 words
The apparatus as set forth in claim 2, wherein all of said branch passages are formed in a direction which converges toward the die axis are joined at an outlet position.
Claim 12
Dependent Claim
63 words
The apparatus as set forth in claim 2, wherein said spherical portions of said cores are eccentrically assembled within said housing, said lip comprises a plurality of substantially concentric rings forming said branch passages therebetween and the thickness of each of said branch passages of said lip is adjustable by means of rotating said cores relative to each other about said spherical portions.
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) | 1977-12-23 | 1978-06-24 | 1978-12-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-23 | 1982-06-24 | 1982-12-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-23 | 1986-06-24 | 1986-12-24 | $7700.00 | Window Closed / Lapsed |