US3577588A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Extrusion apparatus
Assignee: Dow Chemical Co
•
Filing: 1969-05-05
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Granted: 1971-05-04
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Expires: 1989-05-05
Abstract
Abstract A screw having increasing lead or pitch is employed on an extruder with central feed or discharge to provide a selfbalancing extrusion apparatus which does not require heavy thrust bearings.
Inventors
- 👤 Douglas S Chisholm
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 12:49
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/36; B29C48/395; B29C48/455; B29C48/03
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
118 words
A screw extruder, the screw extruder having: a barrel, the barrel defining a generally elongate cylindrical cavity, the barrel having a first end and a second end, a first material passageway disposed at the first end, a second material passageway disposed at the second end, a third material passageway disposed generally between the first and second ends, a screw disposed within the barrel, the screw having a first flight portion extending generally from the first material passageway to the third material passageway, a second flight portion extending from the second material passageway to the third material passageway, the first and second flight portions being of increasing lead and of generally mirror image symmetry; that is, of opposite hand.
Claim 2
Dependent Claim
118 words
A screw extruder, the screw extruder having: a barrel, the barrel defining a generally elongate cylindrical cavity, the barrel having a first end and a second end, a first material passageway disposed at the first end, a second material passageway disposed at the second end, a third material passageway disposed generally between the first and second ends, a screw disposed within the barrel, the screw having a first flight portion extending generally from the first material passageway to the third material passageway, a second flight portion extending from the second material passageway to the third material passageway, the first and second flight portions being of increasing lead and of generally mirror image symmetry; that is, of opposite hand.
Claim 3
Dependent Claim
15 words
The apparatus of claim 1 in operative combination with means to axially position the screw.
Claim 4
Dependent Claim
19 words
The apparatus of claim 1 wherein the first and second portions increase in lead toward the third material passageway.
Claim 5
Dependent Claim
19 words
The apparatus of claim 3 wherein the third passageway is generally centrally disposed between the first and second passageways.
Claim 6
Dependent Claim
11 words
The apparatus of claim 1 including means to rotate the screw.
Claim 7
Dependent Claim
19 words
The apparatus of claim 1 wherein the first and second portions decrease in lead toward the third material passageway.
Claim 8
Dependent Claim
33 words
The apparatus in accordance with claim 1 wherein the means to rotate the screw is a motor operatively coupled thereto by means of a spline connection which permits longitudinal motion of the screw.
Claim 9
Dependent Claim
22 words
The apparatus of claim 7 including means to axially position the screw in operative combination therewith by means of a swivel connector.
References Cited (Backward Citations)
US2437460A
Cited
FR930773A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-03 | 1974-11-02 | 1975-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-03 | 1978-11-02 | 1979-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-03 | 1982-11-02 | 1983-05-04 | $7700.00 | Window Closed / Lapsed |