US3903233A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of and apparatus for extruding concentric plastic sheaths
Assignee: AT&T Inc
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Filing: 1974-06-14
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Granted: 1975-09-02
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Expires: 1994-06-14
Abstract
Abstract First and second concentric insulating sheaths of plastic materials are formed continuously around a filamentary core advancing longitudinally through an extrusion chamber. The core is passed axially through a tapered entrance portion and a coaxially aligned tapered throat portion formed in a separable die disposed in the chamber. Fluent plastic material for the first sheath is delivered from a main extrusion bore, impinging on the core circumferentially at the entrance portion of the die, the flow thereof being developed as it passes into the throat portion thereof. Fluent plastic material for the second sheath is delivered from an auxiliary extrusion bore flowing through a plurality of dividing channels formed in the die and radially inward at a plurality of circumferentially spaced points around the die axis into an annular manifold or reservoir where the fluid pressure of the plastic achieves a steady state condition. The plastic is forced from the manifold circumferentially, flowing in a frustoconical channel formed in the die which terminates in an annular fluid inlet formed in the throat portion of the die to impinge circumferentially around the first sheath, forming both sheaths simultaneously around the core.
Inventors
- 👤 Timothy Stephen Dougherty
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 07:47
CPC Classifications
B; B29; B29C; B29C44/00; B29C44/20; B29C44/32; B29C44/322; B29C48/00; B29C48/03; B29C48/05; B29C48/25; B29C48/30; B29C48/304; B29K; B29K2105/00; B29K2105/06; B29K2105/20; B29L; B29L2031/00; B29L2031/34; B29L2031/3462
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
172 words
A METHOD OF FORMING FIRST SECOND CONCENTRIC SHEATHS OF PLASTIC MATERIAL AROUND A LONGITUDINALY MOVING FILAMENTARY CORE, WHICH COMPRISES THE STEPS OF: PASSING THE CORE THROUGH A CONFINED PASSAGEWAY: INTRODUCING A FIRST FLUENT PLASTIC MATERIAL INTO THE PASSAGEWAY AT AN ENTRANCE SECTION THEREOF CIRCUMFERENTIALLY AROUND AND IN THE DIRECTION OF THE MOVING CORE AND ULTIMATELY ONTO THE CORE: AND INTRODUCING A SECOND FLUENT PLASTIC MATERIAL INTO THE PASSAGEWAAY AT AN INTERMEDIATE SECTION THEREOF AFTER IT HAS FLOWED A SUFFICIENT DISTANCE TO HAVE ACHEVED A UNIFORM DISTRIBUTION OF VECLOCITY AND PRESSURE, CIRCUMFERENTIALLY AROUND AND IN THE DIRECTION OF THE FLOWING FIRST PLASTIC MATERIAL AND THE CORE AND ULTIMATELY ONTO THE FIRST PLASTIC MATERIAL, AT A SUFFICIENT DISTANCE FROM THE POINT OF INTRODUCTION THEREIN OF THE FIRST PLASTIC MATERIAL TO HAVE ALLOWED THE FLOW OF THE FIRST PLASTIC MATERIAL TO HAVVE ACHIEVED A UNIFORM DISTRIBUTION OF VELOCITY AND PRESSURE, TO FORM FIRST AND SECOND CONCENTRIC SHEATHS OF PLASTIC MATERIAL AROUND SAID CORE BETWEEN THE INTERMEDIATE SECTION OF THE PASSAGEWAY AND THE EXIT SECTION THEREOF.
Claim 2
Independent Claim
172 words
A METHOD OF FORMING FIRST SECOND CONCENTRIC SHEATHS OF PLASTIC MATERIAL AROUND A LONGITUDINALY MOVING FILAMENTARY CORE, WHICH COMPRISES THE STEPS OF: PASSING THE CORE THROUGH A CONFINED PASSAGEWAY: INTRODUCING A FIRST FLUENT PLASTIC MATERIAL INTO THE PASSAGEWAY AT AN ENTRANCE SECTION THEREOF CIRCUMFERENTIALLY AROUND AND IN THE DIRECTION OF THE MOVING CORE AND ULTIMATELY ONTO THE CORE: AND INTRODUCING A SECOND FLUENT PLASTIC MATERIAL INTO THE PASSAGEWAAY AT AN INTERMEDIATE SECTION THEREOF AFTER IT HAS FLOWED A SUFFICIENT DISTANCE TO HAVE ACHEVED A UNIFORM DISTRIBUTION OF VECLOCITY AND PRESSURE, CIRCUMFERENTIALLY AROUND AND IN THE DIRECTION OF THE FLOWING FIRST PLASTIC MATERIAL AND THE CORE AND ULTIMATELY ONTO THE FIRST PLASTIC MATERIAL, AT A SUFFICIENT DISTANCE FROM THE POINT OF INTRODUCTION THEREIN OF THE FIRST PLASTIC MATERIAL TO HAVE ALLOWED THE FLOW OF THE FIRST PLASTIC MATERIAL TO HAVVE ACHIEVED A UNIFORM DISTRIBUTION OF VELOCITY AND PRESSURE, TO FORM FIRST AND SECOND CONCENTRIC SHEATHS OF PLASTIC MATERIAL AROUND SAID CORE BETWEEN THE INTERMEDIATE SECTION OF THE PASSAGEWAY AND THE EXIT SECTION THEREOF.
Claim 3
Independent Claim
166 words
A method of forming first and second concentric sheaths of plastic material around a longitudinally moving filamentary core, which comprises the steps of: passing the core through a confined passageway; introducing a first fluent plastic material into the passageway at an entrance section thereof circumferentially around and in the direction of the moving core; preventing the first material from contacting the core until it has passed out of the passageway; and introducing a second fluent plastic material into the passageway at an intermediate section thereof at a uniform distribution of velocity and pressure, circumferentially around and in the direction of the flowing first plastic material and ultimately onto the first plastic material, at a sufficient distance from the point of introduction therein of the first plastic material to have allowed the flow of the first plastic material to have achieved a uniform distribution of velocity and pressure, simultaneously to form first and second concentric sheaths of plastic material around the core passing out of the passageway.
Claim 4
Independent Claim
166 words
A method of forming first and second concentric sheaths of plastic material around a longitudinally moving filamentary core, which comprises the steps of: passing the core through a confined passageway; introducing a first fluent plastic material into the passageway at an entrance section thereof circumferentially around and in the direction of the moving core; preventing the first material from contacting the core until it has passed out of the passageway; and introducing a second fluent plastic material into the passageway at an intermediate section thereof at a uniform distribution of velocity and pressure, circumferentially around and in the direction of the flowing first plastic material and ultimately onto the first plastic material, at a sufficient distance from the point of introduction therein of the first plastic material to have allowed the flow of the first plastic material to have achieved a uniform distribution of velocity and pressure, simultaneously to form first and second concentric sheaths of plastic material around the core passing out of the passageway.
Claim 5
Independent Claim
117 words
A method of forming an outer sheath of plastic material concentrically around an inner sheath of plastic material being extruded onto a longitudinally moving elongated core, which comprises the steps of: directing a plurality of streams of plastic material radially toward the advancing core while the inner sheath is being formed therearound; combining said streams into a single stream flowing in an annular path around and spaced from the advancing core; and forcing a frustoconical stream of plastic after it has flowed a sufficient distance to have achieved a uniform distribution of pressure and velocity, circumferentially from the annular stream toward and in the direction of advancement of the core to impinge circumferentially around the inner sheath.
Claim 6
Independent Claim
117 words
A method of forming an outer sheath of plastic material concentrically around an inner sheath of plastic material being extruded onto a longitudinally moving elongated core, which comprises the steps of: directing a plurality of streams of plastic material radially toward the advancing core while the inner sheath is being formed therearound; combining said streams into a single stream flowing in an annular path around and spaced from the advancing core; and forcing a frustoconical stream of plastic after it has flowed a sufficient distance to have achieved a uniform distribution of pressure and velocity, circumferentially from the annular stream toward and in the direction of advancement of the core to impinge circumferentially around the inner sheath.
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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) | 1978-09-01 | 1979-03-03 | 1979-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-01 | 1983-03-03 | 1983-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-01 | 1987-03-03 | 1987-09-02 | $7700.00 | Window Closed / Lapsed |