US3924992A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for manufacture of partitioned plastic tubing
Assignee: Individual
•
Filing: 1972-07-25
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Granted: 1975-12-09
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Expires: 1992-07-25
Abstract
Abstract Partitioned plastic tubing characterized by a partition within the interior thereof extending in the longitudinal direction and joining at least two points on the internal circumference of the tubing; a process for the manufacture of such partitioned plastic tubing characterized by passing a molten plastic through an annularly shaped zone and cooling the same as it emerges from the zone while maintaining a separate flow of molten plastic on the interior thereof which joins at least two points on the circumference of the interior of the tube being formed; and apparatus for such process, which apparatus comprises an extrusion head, a mandrel therefor defining a passage through which molten plastic flows, and at least one radial discharge slit in the mandrel, which slit is in fluid communication with a reservoir for molten plastic.
Inventors
- 👤 Wilhelm Hegler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 19:22
CPC Classifications
F; F16; F16L; F16L9/00; F16L9/12; F16L9/127; B; B29; B29C; B29C48/00; B29C48/25; B29C48/30; B29C48/32; B29C48/33; B29C49/00; B29C49/0015; B29C49/0021; B29C2791/00; B29C2791/004; B29C2791/006; B29C2949/00; B29C2949/07; B29C2949/075; B29C48/001; B29C48/002; B29C48/03; B29C48/09; B29C48/11; B29C48/13; B29C49/02; B29C49/04; B29C49/04116; B29L; B29L2023/00; B29L2023/18; B29L2024/00; B29L2024/006; B29L2031/00; B29L2031/60
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
124 words
In an apparatus for the manufacture of plastic tubing comprising an extrusion head, a generally annular orifice through which molten plastic can flow, said annular orifice in fluid communication with a reservoir and a mandrel disposed within said extrusion head around which plastic flows, the improvement which comprises at least one radial discharge slit in said mandrel, through which molten plastic can flow to define a wall which slit is in fluid communication with a reservoir for molten plastic and a mold train disposed in a downstream relationship to said extrusion head, means for aspirating air from closed molds in said mold train and means for rotating said mandrel about its common axis with the longitudinal axis of the plastic tube to be formed.
Claim 2
Dependent Claim
124 words
In an apparatus for the manufacture of plastic tubing comprising an extrusion head, a generally annular orifice through which molten plastic can flow, said annular orifice in fluid communication with a reservoir and a mandrel disposed within said extrusion head around which plastic flows, the improvement which comprises at least one radial discharge slit in said mandrel, through which molten plastic can flow to define a wall which slit is in fluid communication with a reservoir for molten plastic and a mold train disposed in a downstream relationship to said extrusion head, means for aspirating air from closed molds in said mold train and means for rotating said mandrel about its common axis with the longitudinal axis of the plastic tube to be formed.
Claim 3
Dependent Claim
40 words
An improvement according to claim 1, wherein the rotatable mandrel is mounted in ball or roller bearings within a stationary member which defines the exterior wall of the plastic tubing to be formed and bears at least one drive sprocket.
Claim 4
Dependent Claim
46 words
An improvement according to claim 2, wherein the bearings and drive sprocket are maintained in a chamber sealed between the rotatable mandrel and the annular orifice through which the plastic flows by a lip which is urged against the mandrel by the pressure of the plastic.
Claim 5
Dependent Claim
20 words
An improvement according to claim 3, wherein the chamber receiving the bearings and drive sprocket is partially filled with lubricant.
Claim 6
Dependent Claim
42 words
An improvement according to claim 1, wherein said mandrEl has a longitudinally positioned bore for the delivery of supporting air, the air entrance aperture of said bore opening into the chamber containing the bearings and sprocket above the level of lubricant therein.
Claim 7
Dependent Claim
17 words
An improvement according to claim 5, wherein said air entrance aperture is surrounded by a drip ring.
References Cited (Backward Citations)
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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) | 1978-12-08 | 1979-06-09 | 1979-12-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-08 | 1983-06-09 | 1983-12-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-08 | 1987-06-09 | 1987-12-09 | $7700.00 | Window Closed / Lapsed |