US5622665A
Expired / Lapsed
US
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Method for making tubing
Assignee: Individual
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Filing: 1995-06-02
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Granted: 1997-04-22
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Expires: 2015-06-02
Abstract
Abstract A method for making differential stiffness tubing for medical products, such as catheters. The method produces a tubing that has a stiff section and a flexible section joined by a relatively short transition section in which the materials of the stiff and flexible sections are wedged into each other in a smooth gradual manner to produce an inseparable bond between the materials without abrupt joints. The method also employs a resin modulating system that minimizes the length of the transition section by minimizing the volumes in all flow channels of the co-extrusion head used to produce the tubing.
Inventors
- 👤 James C. Wang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 10:39
CPC Classifications
A; A61; A61M; A61M25/00; A61M25/0009; A61M25/0043; A61M25/0054; B; B29; B29C; B29C48/00; B29C48/03; B29C48/09; B29C48/11; B29C48/12; B29C48/15; B29C48/151; B29C48/152; B29C48/153; B29C48/16; B29C48/18; B29C48/21; B29C48/25; B29C48/30; B29C48/32; B29C48/335; B29C48/337; B29C48/34; B29C48/92; B29C2948/00; B29C2948/92; B29C2948/92504; B29C2948/9258; B29C2948/926; B29C2948/92819; B29C2948/92828; B29C48/10; B29L; B29L2031/00; B29L2031/753; B29L2031/7542
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
293 words
A method for making an elongated tube having an annular wall with an outer surface and an inner surface that defines a central passageway, the tube also having a first section comprised of a first resinous material, a second section comprised of a second resinous material, the first and second resinous materials being of different stiffness, and an intermediate section joining the first section and the second section, the intermediate section being a transition section in which the wall of the tube gradually changes from the first resinous material of the first section to the second resinous material of the second section to form a continuous unbroken tube of differential stiffness without abrupt joints, said method comprising the steps of: providing a first resinous stream of the first resinous material; providing a second resinous stream of the second resinous material; introducing the first and second resinous materials into separate flow channels in a co-extrusion head that defines a plurality of flow channels; controlling the flow of each of the first and second resinous streams into the co-extrusion head; causing the first resinous stream to join with the second resinous stream in the co-extrusion head to produce a contact volume of joint flow so as to form a wedge structure in the transition section in which the first resinous material extends into the second resinous material so that the second resinous material surrounds the wedge structure of the first material; controlling the flow of each resin stream within the co-extrusion head; and passing the resinous materials through an extrusion die to form a continuous unbroken tube of the desired length having the desired sections formed of the first and second resinous materials with the resinous materials naturally adhering to each other in the sections.
Claim 2
Independent Claim
293 words
A method for making an elongated tube having an annular wall with an outer surface and an inner surface that defines a central passageway, the tube also having a first section comprised of a first resinous material, a second section comprised of a second resinous material, the first and second resinous materials being of different stiffness, and an intermediate section joining the first section and the second section, the intermediate section being a transition section in which the wall of the tube gradually changes from the first resinous material of the first section to the second resinous material of the second section to form a continuous unbroken tube of differential stiffness without abrupt joints, said method comprising the steps of: providing a first resinous stream of the first resinous material; providing a second resinous stream of the second resinous material; introducing the first and second resinous materials into separate flow channels in a co-extrusion head that defines a plurality of flow channels; controlling the flow of each of the first and second resinous streams into the co-extrusion head; causing the first resinous stream to join with the second resinous stream in the co-extrusion head to produce a contact volume of joint flow so as to form a wedge structure in the transition section in which the first resinous material extends into the second resinous material so that the second resinous material surrounds the wedge structure of the first material; controlling the flow of each resin stream within the co-extrusion head; and passing the resinous materials through an extrusion die to form a continuous unbroken tube of the desired length having the desired sections formed of the first and second resinous materials with the resinous materials naturally adhering to each other in the sections.
Claim 3
Dependent Claim
41 words
The method for making an elongated tube of claim 1 in which the contact volume is equal to or greater than the volume of the joint flow of the first and second resinous streams through the die of the co-extrusion head.
Claim 4
Dependent Claim
52 words
The method for making an elongated tube of claim 2 in which the contact volume is equal to or greater than the volume of the joint flow of the first and second resinous streams through the die of the co-extrusion head but less than ten times the volume of said joint flow.
Claim 5
Dependent Claim
26 words
The method for making an elongated tube of claim 1 wherein said contact volume of joint flow within the co-extrusion head is at or near zero.
Claim 6
Dependent Claim
110 words
The method for making an elongated tube of claim 1 further comprising the steps of: providing an additional resinous stream of an additional resinous material having a property intermediate to that of said first and said second resinous materials; introducing said additional resinous material into a flow channel in said co-extrusion head separate from those into which said first and second resinous materials are introduced; controlling the flow of said additional resinous stream into said co-extrusion head; and causing said additional resinous stream to join with said first and second resinous streams within the co-extrusion head to produce an additional contact volume of joint flow to form the transition section.
Claim 7
Dependent Claim
140 words
The method of making an elongated tube of claim 1 wherein said elongated tube has a plurality of first sections, a plurality of second sections, and a plurality of intermediate sections; wherein said first and second sections are alternately disposed along the length of said tube: and wherein each of said first sections is joined to at least one of said second sections by one of said transition sections, the wall of said tube gradually changing from said first resinous material of said first section to said second resinous material of said second section; and further comprising the step of cutting said elongated tube to form a plurality of tube segments, each segment including at least one transition section, at least a portion of one of said first sections, and at least a portion of one of said second sections.
Claim 8
Dependent Claim
81 words
A method for making an elongated tube of claim 1 wherein the flow of said first resinous stream and the flow of said second resinous stream into said co-extrusion head are controlled relative to each other so that the inner diameters of said first section, said transition section, and said second section of said tube are substantially equal and so that the outer diameters of said first section, said transition section, and said second section of said tube are substantially equal.
Claim 9
Dependent Claim
78 words
A method for making an elongated tube of claim 4 wherein the contact volume, the volume of flow of the joined resinous materials within the die of the co-extrusion head, and the volume of flow of the joined resinous materials between said contact volume and the exit of the joined resinous materials from the die, if any, combine to produce a skewing volume; and wherein said skewing volume is greater than the volume of said tube first section.
Claim 10
Dependent Claim
28 words
A method for making an elongated tube of claim 8 wherein said skewing volume is at least five times greater than the volume of said tube first section.
Claim 11
Dependent Claim
36 words
The method of claim 1 including controlling the flow of the first and second resinous streams in synchronized fashion and stopping the flow of each resinous stream abruptly to produce a transition section of desired length.
Claim 12
Dependent Claim
41 words
The method of claim 10 including controllably bleeding the first resinous material from the co-extrusion head to relieve residual pressure and thereby facilitate the abrupt stopping of the resin flow so as to control of the length of the transition section.
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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) | 2000-04-21 | 2000-10-21 | 2001-04-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-04-21 | 2004-10-21 | 2005-04-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-04-21 | 2008-10-21 | 2009-04-22 | $7700.00 | Window Closed / Lapsed |