US4099897A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for producing foamed plastic insulated wires
Assignee: Hitachi Cable Ltd
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Filing: 1975-11-04
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Granted: 1978-07-11
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Expires: 1995-11-04
Abstract
Abstract An extrusion apparatus and method for producing foamed resin coatings on a wire. A foaming agent and molten resin are poured into a supply portion of an extruding screw and cylinder apparatus. The screw in the supply portion is tapered in the down stream direction. The screw and cylinder apparatus portion adjacent to the supply portion is arranged to blend the resin and foaming agent and has a lower coefficient of extrusion than the supply portion. The metering portion of the screw and cylinder apparatus is adjacent and down stream of the blend portion and has a higher coefficient of extrusion than the blend portion.
Inventors
- 👤 Hideo Takano
- 👤 Satoshi Saito
- 👤 Tadashi Sato
- 👤 Tuyoshi Yamaguchi
- 👤 Yoshihiro Narita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 21:42
CPC Classifications
B; B29; B29C; B29C44/00; B29C44/20; B29C44/32; B29C44/322; B29C48/00; B29C48/03; B29C48/05; B29C48/25; B29C48/36; B29C48/395; B29C48/06
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
149 words
An apparatus for producing foamed plastic insulated wires including an extruding machine comprising a supply portion, said supply portion having means for receiving under pressure a molten thermoplastic resin and a foaming agent, a blend portion positioned to receive said resin and said foaming agent from said supply portion for blending said resin and foaming agent, and a metering portion positioned to receive blended resin and foaming agent from said blend portion for metering said blended resin and foaming agent to deliver same to a cross head, said supply, blend and metering portions being sections of an extrusion cylinder and an extrusion screw, said portions having respective extrusion coefficients α 1 , α 2 and α 3 which are related to one another as follows: α.sub.1 > α.sub.3 > α.sub.2 said extrusion coefficients being a function of screw contour and defining the volume extruded per revolution of the screw.
Claim 2
Independent Claim
149 words
An apparatus for producing foamed plastic insulated wires including an extruding machine comprising a supply portion, said supply portion having means for receiving under pressure a molten thermoplastic resin and a foaming agent, a blend portion positioned to receive said resin and said foaming agent from said supply portion for blending said resin and foaming agent, and a metering portion positioned to receive blended resin and foaming agent from said blend portion for metering said blended resin and foaming agent to deliver same to a cross head, said supply, blend and metering portions being sections of an extrusion cylinder and an extrusion screw, said portions having respective extrusion coefficients α 1 , α 2 and α 3 which are related to one another as follows: α.sub.1 > α.sub.3 > α.sub.2 said extrusion coefficients being a function of screw contour and defining the volume extruded per revolution of the screw.
Claim 3
Dependent Claim
30 words
The apparatus of claim 1, wherein said screw in said blend portion is a mixing device having a plurality of grooves which have a helical angle to the downstream direction.
Claim 4
Dependent Claim
25 words
The apparatus of claim 1, wherein the screw in said supply portion is tapered to a deeper groove in the downstream direction of said apparatus.
Claim 5
Dependent Claim
49 words
The apparatus of claim 1, wherein the compression ratio is between 1.4 and 0.75 inclusive, said compression ratio being defined as the volume surrounded by one pitch of said screw in the metering portion divided by the volume surrounded by one pitch of said screw in the supply portion.
Claim 6
Dependent Claim
15 words
The apparatus of claim 4, wherein said compression ratio is between 1.3 and 0.95 inclusive.
Claim 7
Dependent Claim
29 words
The apparatus of claim 1, wherein said supply portion further comprises a foaming agent inlet and a resin inlet, said resin inlet being downstream of said foaming agent inlet.
Claim 8
Dependent Claim
55 words
The apparatus of claim 6, wherein said foaming agent inlet is separated from said resin inlet by a distance of from 2D to 7D, where D is the caliber of said screw in said supply portion, and wherein said resin inlet is separated from said blend portion by a distance of from 2D to 5D.
Claim 9
Dependent Claim
17 words
The apparatus of claim 7, wherein said blend portion has a length of from 2D to 7D.
Claim 10
Dependent Claim
33 words
The apparatus of claim 2, wherein said compression ratios have the relationships, α 1 /α 2 is between 1.21 and 1.71 inclusive and α 3 /α 2 is between 1.11 and 1.61 inclusive.
Claim 11
Dependent Claim
33 words
The apparatus of claim 2, wherein said compression ratios have the relationships, α 1 /α 2 is between 1.45 and 1.60 inclusive, and α 3 /α 2 is between 1.35 and 1.45 inclusive.
Claim 12
Dependent Claim
24 words
The apparatus of claim 2, wherein the compression ratios are related as follows, α.sub.2 : α.sub.3 : α.sub.1 = 1 : 1.42 : 1.52
Claim 13
Dependent Claim
38 words
The apparatus of claim 1, wherein said screw in said blend portion comprises a screw shaft reduced in diameter relative to the screw shaft in said supply portion and a plurality of posts implanted on said screw shaft.
Claim 14
Dependent Claim
40 words
The apparatus of claim 1, wherein said screw in said blend portion comprises a plurality of equally spaced spur gears carried by a screw shaft, each of said spur gears having an identical thickness but a different number of teeth.
Claim 15
Dependent Claim
37 words
The apparatus of claim 1, wherein said screw in said blend portion comprises a screw shaft having double threading relative to the screw shaft in said supply portion and a plurality of axial slots through the threading.
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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) | 1981-07-10 | 1982-01-09 | 1982-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-07-10 | 1986-01-09 | 1986-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-07-10 | 1990-01-09 | 1990-07-11 | $7700.00 | Window Closed / Lapsed |