Patent US4729666A successfully refreshed from Google Patents.
US4729666A
Expired / Lapsed
US
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Screw for molding thermoplastic resin having a stress relaxation section
Assignee: Idemitsu Kosan Co Ltd
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Filing: 1986-08-15
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Granted: 1988-03-08
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Expires: 2006-08-15
Abstract
Abstract This invention relates to a screw used in an equipment for molding thermoplastic resin, in which a mixing section is provided at a position adjacent a shearing section, and the pitch of a stress relaxation section is preset to the pitch, at which satisfactory kneading can be performed without giving high shearing to the resin. With this screw, even if high-speed extrusion molding is performed, the pressure of resin is not fluctuated, molded parts can avoid lowered material quality and outstanding molded parts can be provided.
Inventors
- 👤 Toyokazu Takubo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 20:25
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/03; B29C48/07; B29C48/08
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
125 words
A screw for molding thermoplastic resin, comprising: a feed section, a compression section which is a relaxed compression section having a compression ratio in the range of 3 or less, a shearing section and a stress relaxation section being successively provided from a resin feed side to a resin extrusion side, and a mixing section being provided intermediate said shearing section and said stress relaxation section, the length of said shearing section being in the range of 0.2-2 times the diameter of said screw, the length of said stress relaxation section being in the range of 4-15 times the diameter of said screw, and a ratio L/D between the total length L and the diameter D of said screw being in the range of 15-40.
Claim 2
Dependent Claim
125 words
A screw for molding thermoplastic resin, comprising: a feed section, a compression section which is a relaxed compression section having a compression ratio in the range of 3 or less, a shearing section and a stress relaxation section being successively provided from a resin feed side to a resin extrusion side, and a mixing section being provided intermediate said shearing section and said stress relaxation section, the length of said shearing section being in the range of 0.2-2 times the diameter of said screw, the length of said stress relaxation section being in the range of 4-15 times the diameter of said screw, and a ratio L/D between the total length L and the diameter D of said screw being in the range of 15-40.
Claim 3
Dependent Claim
26 words
A screw for molding thermoplastic resin as set forth in claim 1, wherein said feed section is a straight screw having a compression ratio of 1.
Claim 4
Dependent Claim
24 words
A screw for molding thermoplastic resin as set forth in claim 1, wherein said compression ratio is in the range of 2.5 or less.
Claim 5
Dependent Claim
19 words
A screw for molding thermoplastic resin as set forth in claim 1, wherein said shearing section is a torpedo.
Claim 6
Dependent Claim
31 words
A screw for molding thermoplastic resin as set forth in claim 1, wherein the length of said shearing section is in the range of 0.3-1.5 times the diameter of said screw.
Claim 7
Dependent Claim
27 words
A screw for molding thermoplastic resin as set forth in claim 1, wherein said mixing section is contiguous with said shearing section on said resin extrusion side.
Claim 8
Dependent Claim
19 words
A screw for molding thermoplastic resin as set forth in claim 1, wherein said mixing section comprises gear wheels.
Claim 9
Dependent Claim
46 words
A screw for molding thermoplastic resin as set forth in claim 7, wherein said plurality of said gear wheels are spaced a predetermined distance apart from one another, and the outer diameter of said gear wheels is equal to the outer diameter of said shearing section.
Claim 10
Dependent Claim
25 words
A screw for molding thermoplastic resin as set forth in claim 1, wherein mixing sections are provided at opposite axial ends of said shearing section.
Claim 11
Dependent Claim
20 words
A screw for molding thermoplastic resin as set forth in claim 9, wherein said mixing sections each comprise gear wheels.
Claim 12
Dependent Claim
106 words
A screw for molding thermoplastic resin, comprising: a feed section, a compression section, a shearing section and a stress relaxation section are successively provided from a resin feed side to a resin extrusion side, said screw having at least one thread in each of said sections, the pitch of at least part of said thread in said stress relaxation section being in the range of 0.3-0.8 times the pitch of the thread in at least one of said feed section and said compression section, and a ratio L/D between the total length L and the diameter D of said screw is in the range of 15-40.
Claim 13
Dependent Claim
106 words
A screw for molding thermoplastic resin, comprising: a feed section, a compression section, a shearing section and a stress relaxation section are successively provided from a resin feed side to a resin extrusion side, said screw having at least one thread in each of said sections, the pitch of at least part of said thread in said stress relaxation section being in the range of 0.3-0.8 times the pitch of the thread in at least one of said feed section and said compression section, and a ratio L/D between the total length L and the diameter D of said screw is in the range of 15-40.
Claim 14
Dependent Claim
26 words
A screw for molding thermoplastic resin as set forth in claim 11, wherein said stress relaxation section has a compression ratio in the range of 2-0.5.
Claim 15
Dependent Claim
26 words
A screw for molding thermoplastic resin as set forth in claim 11, wherein said stress relaxation section has a compression ratio in the range of 1.6-0.8.
Claim 16
Dependent Claim
27 words
A screw for molding thermoplastic resin as set forth in claim 11, wherein a mixing section is contiguous with said shearing section on said resin extrusion side.
Claim 17
Dependent Claim
27 words
A screw for molding thermoplastic resin as set forth in claim 11, wherein a mixing section is contiguous with said shearing section on said resin feed side.
Claim 18
Dependent Claim
36 words
A screw for molding thermoplastic resin as set forth in claim 11, wherein mixing sections are provided at opposite axial ends of said shearing section on both the resin extrusion and the resin feed sides, respectively.
Claim 19
Dependent Claim
19 words
A screw for molding thermoplastic resin as set forth in claim 16, wherein said mixing section comprises gear wheels.
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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) | 1991-03-08 | 1991-09-07 | 1992-03-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-08 | 1995-09-07 | 1996-03-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-08 | 1999-09-07 | 2000-03-08 | $7700.00 | Window Closed / Lapsed |