US3671021A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Extruder and screw therefor with undercut melt conducting channel
Assignee: Somerset Technologies Inc
•
Filing: 1970-08-26
•
Granted: 1972-06-20
•
Expires: 1990-08-26
Abstract
Abstract A screw type extruder for reducing a solid thermoplastic material to a fluid wherein a spiral body of uniform width of the material is maintained in continuous contact with the barrel of the extruder and the screw is formed with a secondary or subchannel arranged substantially underneath a solid body supported within the main channel for conducting the melted material toward the discharging end of the extruder.
Inventors
- 👤 Anthony W Pomper
- 👤 Lloyd Kovacs
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 12:38
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/36; B29C48/50; B29C48/505; B29C48/59; B29C48/03
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
173 words
An extruder having a rotatable screw and a barrel enclosing said screw: said screw comprising a core and a thread so interrelated in shape as to define a continuous spiral main channel through which material is traversed forwardly to the front discharge end of the extruder, said screw having a melt section extending through a substantial portion of the length of the main channel; said thread being of substantially uniform pitch and width throughout said melt section, said core being shaped to define the bottom surface of the main channel substantially parallel to the screw axis, a relatively narrow portion of said bottom surface being radially undercut with respect to the remaining portion throughout said melt section to define a subchannel for the escape of melted plastic to said front end, said remaining portion being relatively wide with respect to said narrow portion to provide substantial support for a body of said solid material between adjacent turns of the thread exteriorly of the subchannel without substantial intrusion of said body into said subchannel.
Claim 2
Dependent Claim
173 words
An extruder having a rotatable screw and a barrel enclosing said screw: said screw comprising a core and a thread so interrelated in shape as to define a continuous spiral main channel through which material is traversed forwardly to the front discharge end of the extruder, said screw having a melt section extending through a substantial portion of the length of the main channel; said thread being of substantially uniform pitch and width throughout said melt section, said core being shaped to define the bottom surface of the main channel substantially parallel to the screw axis, a relatively narrow portion of said bottom surface being radially undercut with respect to the remaining portion throughout said melt section to define a subchannel for the escape of melted plastic to said front end, said remaining portion being relatively wide with respect to said narrow portion to provide substantial support for a body of said solid material between adjacent turns of the thread exteriorly of the subchannel without substantial intrusion of said body into said subchannel.
Claim 3
Dependent Claim
59 words
The extruder of claim 1 wherein: said subchannel extends along the rear side of said thread and the thread has openings slanting radially inwardly and rearwardly therethrough from a surface along the front side of the thread into said subchannel for flowing of liquid rearwardly through the thread from a channel region adjacent the front side of the thread.
Claim 4
Dependent Claim
69 words
The extruder of claim 1 wherein: said subchannel extends along the rear side of the thread and the thread has a peripheral bevel surface tapering frontwardly toward and joining with the leading side of the thread; and the thread has openings slanting radially inwardly and rearwardly from said bevel surface and joining with said subchannel for the passage of liquid rearwardly through the thread from the front side thereof.
Claim 5
Dependent Claim
36 words
The extruder of claim 1 wherein: said subchannel extends along the rear side of said thread; and said channel bottom surface has axially extending grooves extending completely crosswise of said remaining portion of the bottom surface.
Claim 6
Dependent Claim
40 words
The extruder of claim 1 wherein: a plurality of said subchannels are provided in said channel bottom surface which extend in spiral conformity with the thread; and said bottom surface provides a plurality of axially extending grooves interconnecting said subchannels.
Claim 7
Dependent Claim
94 words
The extruder of claim 1 wherein: the screw provides a subchannel adjacent the rearside of said thread and a groove within the outer periphery of said thread separated by adjacent frontward channel portion by a ridge of the thread of less radial height than that of maximum radius separating the groove from the subchannel; and said thread, having a plurality of openings connecting said groove with said channel, said openings slanting radially inwardly and rearwardly through said thread portion of maximum radius for the passage of liquid collected in said groove into said subchannel.
Claim 8
Dependent Claim
26 words
The extruder of claim 1 wherein: said subchannel is of uniform width throughout its length and increasing radial depth in the forward direction of the extruder.
Claim 9
Dependent Claim
19 words
The extruder of claim 7 wherein: said subchannel extends to and emerges in the front end of the screw.
Claim 10
Dependent Claim
160 words
An extruder having a rotatable screw and a barrel enclosing said screw: said screw comprising a core and a thread so interrelated in shape as to define a continuous spiral main chaNnel through which material is traversed forwardly to the front discharge end of the extruder, said screw having a melt section extending through a substantial portion of the length of the main channel; said core being shaped to define the bottom surface of the main channel substantially parallel to the screw axis, a relatively narrow portion of said bottom surface being radially undercut with respect to the remaining portion throughout said melt section to define a subchannel for the escape of melted plastic to said front end, said remaining portion being relatively wide with respect to said narrow portion to provide substantial support for a body of said solid material between adjacent turns of the thread exteriorly of the subchannel without substantial intrusion of said body into said subchannel.
Claim 11
Dependent Claim
160 words
An extruder having a rotatable screw and a barrel enclosing said screw: said screw comprising a core and a thread so interrelated in shape as to define a continuous spiral main chaNnel through which material is traversed forwardly to the front discharge end of the extruder, said screw having a melt section extending through a substantial portion of the length of the main channel; said core being shaped to define the bottom surface of the main channel substantially parallel to the screw axis, a relatively narrow portion of said bottom surface being radially undercut with respect to the remaining portion throughout said melt section to define a subchannel for the escape of melted plastic to said front end, said remaining portion being relatively wide with respect to said narrow portion to provide substantial support for a body of said solid material between adjacent turns of the thread exteriorly of the subchannel without substantial intrusion of said body into said subchannel.
References Cited (Backward Citations)
US3123860A
Cited
US2343529A
Cited
CH420581A
Cited
US3358327A
Cited
US3375549A
Cited
US3271819A
Cited
US3445890A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-20 | 1975-12-20 | 1976-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-20 | 1979-12-20 | 1980-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-20 | 1983-12-20 | 1984-06-20 | $7700.00 | Window Closed / Lapsed |