Patent US4329314A successfully refreshed from Google Patents.
US4329314A
Expired / Lapsed
US
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Method and apparatus for inside frosting of tubing
Assignee: Mallinckrodt Inc
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Filing: 1980-10-31
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Granted: 1982-05-11
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Expires: 2000-10-31
Abstract
Abstract Provision is made for evenly controlling the cooling of the inner die pin of an extrusion die assembly so that the hot plastic coming in contact therewith is frosted. A conduit extends through the inner die pin to a point near the tip of the inner die pin. A cap is mounted on the end of the conduit and spaced from the front face thereof to provide an annular discharge opening. At least the tip portion of the inner die pin is formed of a material of good heat conductivity, such as brass, and the cooling air is directed through the discharge opening relatively evenly over the inner portion of the inner die pin to effect uniform inside frosting of a plastic tube formed in the apparatus. The inside of the plastic tube is open to the atmosphere. To maintain proper size the extruded tube is directed from the extrusion die assembly into sizing plates in a vacuum sizing and cooling chamber wherein a lower than atmospheric pressure is maintained on the exterior of the tube, and coolant is supplied to the chamber so as to surround the exterior of the tube.
Inventors
- 👤 Isaac S. Jackson
- 👤 L. Nelson Tilford
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:02
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/88; B29C48/90; B29C48/03; B29C48/09; B29C48/30; B29C48/32; B29C48/34; B29C48/78; B29C48/86; B29C48/87; B29C48/911; B29C48/9115; B29C48/9135; B29C48/915; B29C48/916; B29C48/06; B29C48/15; B29C48/154; B29C48/905
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
160 words
In an extrusion die assembly for a plastic tube which includes an inner die pin and an outer die bushing and a passage therebetween through which plastic is extruded for forming the tube, means for providing inside frosting of the tube comprising: (a) a passage extending through said inner die pin; (b) a conduit positioned in said passage and extending through said inner die pin; (c) said conduit being connectible to a source of air under pressure; (d) at least the tip portion of said inner die pin being formed of a material having good heat conductivity; and (e) means at the inner end of said conduit for directing air uniformly against the inner surface of said tip portion for cooling said inner die pin to produce frosting of the inner surface of the tube; (f) the tube being open to the atmosphere so that air supplied through said conduit may be discharged through the open end of the tube.
Claim 2
Dependent Claim
160 words
In an extrusion die assembly for a plastic tube which includes an inner die pin and an outer die bushing and a passage therebetween through which plastic is extruded for forming the tube, means for providing inside frosting of the tube comprising: (a) a passage extending through said inner die pin; (b) a conduit positioned in said passage and extending through said inner die pin; (c) said conduit being connectible to a source of air under pressure; (d) at least the tip portion of said inner die pin being formed of a material having good heat conductivity; and (e) means at the inner end of said conduit for directing air uniformly against the inner surface of said tip portion for cooling said inner die pin to produce frosting of the inner surface of the tube; (f) the tube being open to the atmosphere so that air supplied through said conduit may be discharged through the open end of the tube.
Claim 3
Dependent Claim
17 words
The apparatus of claim 1 wherein tip portion of said inner die pin is formed of brass.
Claim 4
Dependent Claim
26 words
The apparatus of claim 1 including means for adjusting said conduit to vary the position of said means for directing air against said inner die pin.
Claim 5
Dependent Claim
53 words
The apparatus of claim 1 wherein said means for directing air comprises a cap received at the end of said conduit and positioned to provide an annular opening between the front face of said conduit and said cap for discharge of air uniformly against the inner circumferential surface of said inner die pin.
Claim 6
Dependent Claim
28 words
The apparatus of claim 4 wherein said cap includes an inner surface spaced from and parallel to said front face of said conduit to provide said annular opening.
Claim 7
Dependent Claim
28 words
The apparatus of claim 5 wherein said inner surface of said cap is substantially flat and air is discharged radially through said opening against said inner die pin.
Claim 8
Dependent Claim
50 words
The apparatus of claim 5 wherein said cap includes: (a) an inner surface shaped to direct air from said conduit outwardly against said inner die pin; and (b) a plurality of fingers spaced equidistantly around said inner surface and received on said conduit for positioning said cap on said conduit.
Claim 9
Dependent Claim
33 words
The apparatus of claim 1 wherein a vacuum sizing and cooling chamber is disposed between the extrusion die assembly and the open end of the tube and the tube extends through said chamber.
Claim 10
Independent Claim
112 words
A method for frosting the inside surface of a tube simultaneously with the extrusion of the tube comprising: (a) providing an inner die pin at least the tip portion of which is formed of a material of good heat conductivity; (b) supplying air under pressure through a conduit extending to a point near the tip of said inner die pin; (c) directing the air uniformly against the inner surface of the tip portion of said inner die pin for cooling said inner die pin to induce frosting of the tube being extruded over said inner die pin; and (d) leaving the end of the tube open to allow escape of air therethrough.
Claim 11
Independent Claim
112 words
A method for frosting the inside surface of a tube simultaneously with the extrusion of the tube comprising: (a) providing an inner die pin at least the tip portion of which is formed of a material of good heat conductivity; (b) supplying air under pressure through a conduit extending to a point near the tip of said inner die pin; (c) directing the air uniformly against the inner surface of the tip portion of said inner die pin for cooling said inner die pin to induce frosting of the tube being extruded over said inner die pin; and (d) leaving the end of the tube open to allow escape of air therethrough.
Claim 12
Dependent Claim
30 words
The method of claim 9 including providing a vacuum sizing and cooling chamber adjacent the extrusion die assembly and causing the tube to pass through said chamber immediately after extrusion.
Claim 13
Dependent Claim
39 words
The apparatus of claim 1 wherein said tip portion of said inner die pin is made thinner than the remainder of said inner die pin to increase the heat conductivity from the extruded tube through the inner die pin.
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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) | 1985-05-10 | 1985-11-09 | 1986-05-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-05-10 | 1989-11-09 | 1990-05-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-05-10 | 1993-11-09 | 1994-05-11 | $7700.00 | Window Closed / Lapsed |