US3913897A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Single-thread feed screw for extruders and the like
Assignee: Mannesmann Demag Krauss Maffei GmbH
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Filing: 1973-11-21
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Granted: 1975-10-21
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Expires: 1993-11-21
Abstract
Abstract The thread of a one-thread feed screw is interrupted at several locations in a compression zone to form gaps between the end of the last turn of a preceding thread section and the beginning of the first turn of the next-following thread section, each thread section encompassing two to three turns. The several thread sections may be of like or different length but in either case are so dimensioned that alternate gaps lie on opposite sides of the screw core.
Inventors
- 👤 Wilhelm Hanslik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:48
CPC Classifications
F; F04; F04D; F04D3/00; F04D3/02; B; B29; B29C; B29C48/00; B29C48/03
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
95 words
In an extruder comprising a generally cylindrical housing and a driven feed screw in said housing defining therewith an upstream compression zone and a downstream expansion zone, the improvement wherein said feed screw has a single thread divided by at least one peripheral gap into a plurality of sections axially adjoining one another within said compressing zone, each of said sections extending over at least one full turn of thread, successive sections terminating in peripherally staggered downstream ends said downstream ends of the successive sections being peripherally offset from each other by about 180* degrees.
Claim 2
Dependent Claim
95 words
In an extruder comprising a generally cylindrical housing and a driven feed screw in said housing defining therewith an upstream compression zone and a downstream expansion zone, the improvement wherein said feed screw has a single thread divided by at least one peripheral gap into a plurality of sections axially adjoining one another within said compressing zone, each of said sections extending over at least one full turn of thread, successive sections terminating in peripherally staggered downstream ends said downstream ends of the successive sections being peripherally offset from each other by about 180* degrees.
Claim 3
Dependent Claim
26 words
The improvement defined in claim 1 wherein the length of each gap and the length of each section amounts to substantially a whole number of quarter-turns.
Claim 4
Dependent Claim
19 words
The improvement defined in claim 2 wherein each gap has a length ranging between substantially one and two quarter-turns.
Claim 5
Dependent Claim
15 words
The improvement defined in claim 3 wherein each section encompasses between two and three turns.
Claim 6
Dependent Claim
25 words
The improvement defined in claim 4 wherein the angular spacing between said downstream ends of adjoining sections is 900* as measured around the intervening turns.
Claim 7
Dependent Claim
47 words
The improvement defined in claim 1 wherein said sections have the same number of downstream ends disposed on opposite sides within said compression zone, the number of said sections being greater than two with alternate gaps disposed on opposite sides of the axis of said feed screw.
Claim 8
Dependent Claim
16 words
The improvement defined in claim 1 wherein said sections all lie on a common helicoidal line.
Claim 9
Dependent Claim
26 words
The imprOvement defined in claim 1 wherein alternate sections lie on interleaved helicoidal lines and have adjoining turns separated by a fraction of a pitch length.
Claim 10
Dependent Claim
15 words
The improvement defined in claim 8 wherein the ends of said adjoining turns axially overlap.
Claim 11
Dependent Claim
19 words
The improvement defined in claim 8 wherein the ends of said adjoining turns lie in a common radial plane.
Claim 12
Dependent Claim
15 words
The improvement defined in claim 10 wherein said sections are all of the same length.
Claim 13
Dependent Claim
20 words
The improvement defined in claim 10 wherein adjoining sections have upstream ends peripherally offset from each other by about 180*.
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) | 1978-10-20 | 1979-04-21 | 1979-10-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-20 | 1983-04-21 | 1983-10-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-20 | 1987-04-21 | 1987-10-21 | $7700.00 | Window Closed / Lapsed |