Patent US3858856A successfully refreshed from Google Patents.
US3858856A
Expired / Lapsed
US
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Extruder screw
Assignee: Hoover Universal Inc
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Filing: 1973-01-26
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Granted: 1975-01-07
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Expires: 1993-01-26
Abstract
Abstract An extruder screw for plastic extruding apparatus which includes a solid transport section and a melt transport section. In the melt transport section, the screw is provided with a barrier flight which provides separation of unmelted plastic or solids in a solids feed channel spaced from melted plastic in a melt feed channel. The bases of the solids and melt feed channels in the melt transport section are tapered reversely to each other.
Inventors
- 👤 John S Hsu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 12:22
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/36; B29C48/50; B29C48/505; B29C48/64; B29C48/66; B29B; B29B7/00; B29B7/30; B29B7/34; B29B7/38; B29B7/40; B29B7/42; B29B7/428; B29B7/429; B29C48/03
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
194 words
An extruder screw adapated to be mounted in the barrel of an extruder apparatus, said screw comprising a solids transport section along an end length of said screw and a melt transport section along an intermediate length of said screw, said solids transport section including a helical thread defining a main flight of a predetermined constant lead to form a solids feed channel, said melt transport section having a helical thread defining a main flight of substantially the same lead as said main flight of said solids transport section, and a second helical thread defining a barrier flight lengthwise spaced from said main flight to form a Melt channel separate from said solids feeds channel, said main flight in said melt transport section being initiated at a point displaced from the end of the main flight in said solids transport section, and said barrier flight being a continuation of said main flight in said solids transport section, said melt channel having a root diameter tapering downwardly from the end of said solids transport section, and said solids feed channel having a root diameter tapering reversely from the root diamter taper of said melt channel.
Claim 2
Dependent Claim
194 words
An extruder screw adapated to be mounted in the barrel of an extruder apparatus, said screw comprising a solids transport section along an end length of said screw and a melt transport section along an intermediate length of said screw, said solids transport section including a helical thread defining a main flight of a predetermined constant lead to form a solids feed channel, said melt transport section having a helical thread defining a main flight of substantially the same lead as said main flight of said solids transport section, and a second helical thread defining a barrier flight lengthwise spaced from said main flight to form a Melt channel separate from said solids feeds channel, said main flight in said melt transport section being initiated at a point displaced from the end of the main flight in said solids transport section, and said barrier flight being a continuation of said main flight in said solids transport section, said melt channel having a root diameter tapering downwardly from the end of said solids transport section, and said solids feed channel having a root diameter tapering reversely from the root diamter taper of said melt channel.
Claim 3
Dependent Claim
19 words
The invention as defined in claim 1 wherein said barrier flight is of lesser diameter than said main flight.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-01-06 | 1978-07-08 | 1979-01-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-06 | 1982-07-08 | 1983-01-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-06 | 1986-07-08 | 1987-01-07 | $7700.00 | Window Closed / Lapsed |