US3684419A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Screen changer for extruders
Assignee: Individual
•
Filing: 1971-01-25
•
Granted: 1972-08-15
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Expires: 1991-01-25
Abstract
Abstract An automatic screen changer for use with plastic extruder machines and utilizing hydraulic pressure to provide an annular fluid seal around the screen. A control system automatically reduces seal pressure in response to actuation of a screen changing slide member.
Inventors
- 👤 Bradford R Voight
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 06:59
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/36; B29C48/50; B29C48/69; B29C48/693; B29C48/254; B29C48/2545; B29C48/255; B29C48/2554; B29C48/691; B29C48/6912; B29C48/03
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
221 words
Apparatus for extruding plastic materials comprising: a. housing means comprising extruder block means adapted for connection to an extruder and having an inlet opening for passing plastic material transmitted thereby, die block means adapted for connection to an extrusion die and having an outlet opening for passing plastic material thereto, connector means for connecting said extruder block means to said die block means so as to axially align said inlet opening with said outlet opening; b. slide means disposed between said extruder block means and said die block means and defining a plurality of spaced apart openings; c. guide means defining for said slide means a path of movement that sequentially aligns said spaced apart openings with said axially aligned inlet and outlet openings; d. annular seal members disposed between said slide means and each of said extruder block means and said die block means, said annular seal members being axially aligned with said inlet and outlet openings and adapted to engage peripheral portions of said slide means surrounding said openings therein; e. force producing means for exerting a sealing force between said slide means and said annular seal members, said force producing means comprising a source of fluid pressure, and a pressure cavity partially defined by one of said annular seal members and communicating with said source of fluid pressure.
Claim 2
Dependent Claim
221 words
Apparatus for extruding plastic materials comprising: a. housing means comprising extruder block means adapted for connection to an extruder and having an inlet opening for passing plastic material transmitted thereby, die block means adapted for connection to an extrusion die and having an outlet opening for passing plastic material thereto, connector means for connecting said extruder block means to said die block means so as to axially align said inlet opening with said outlet opening; b. slide means disposed between said extruder block means and said die block means and defining a plurality of spaced apart openings; c. guide means defining for said slide means a path of movement that sequentially aligns said spaced apart openings with said axially aligned inlet and outlet openings; d. annular seal members disposed between said slide means and each of said extruder block means and said die block means, said annular seal members being axially aligned with said inlet and outlet openings and adapted to engage peripheral portions of said slide means surrounding said openings therein; e. force producing means for exerting a sealing force between said slide means and said annular seal members, said force producing means comprising a source of fluid pressure, and a pressure cavity partially defined by one of said annular seal members and communicating with said source of fluid pressure.
Claim 3
Dependent Claim
44 words
Apparatus according to claim 1 wherein said force producing means further comprises a piston member movably disposed in said pressure cavity and adapted to exert said sealing force by forcibly engaging said one seal member in response to fluid pressure in said pressure cavity.
Claim 4
Dependent Claim
24 words
Apparatus according to claim 2 wherein said pressure cavity and said piston member are annular and are axially aligned with said one seal members
Claim 5
Dependent Claim
48 words
Apparatus according to claim 3 wherein said cavity is partially defined by one of said extruder block means and said die block means and said source of fluid pressure comprises an inlet channel defined thereby and communicating with an end of said cavity opposite said one seal member.
Claim 6
Dependent Claim
55 words
Apparatus according to claim 4 including a plurality of spaced apart inner ring seals disposed between a wall of said cavity and an inner wall of said annular piston member and a plurality of spaced apart outer ring seals disposed between a wall of said cavity and an outer wall of said annular piston member.
Claim 7
Dependent Claim
40 words
Apparatus according to claim 5 wherein said block partially defining said cavity further defines an inner vent orifice terminating between adjacent wall portions of said cavity and said piston member at a position between a pair of said ring seals.
Claim 8
Dependent Claim
26 words
Apparatus according to claim 1 including power actuator means for producing movement of said slide means between said extruder block means and said die block means.
Claim 9
Dependent Claim
18 words
Apparatus according to claim 7 including pressure relief means for selectively reducing the fluid pressure in said cavity.
Claim 10
Dependent Claim
39 words
Apparatus according to claim 8 including control means for automatically activating said pressure relief means to reduce the fluid pressure in said cavity in response to actuation of said power actuator means to produce movement of said slide means.
Claim 11
Dependent Claim
44 words
Apparatus according to claim 9 wherein said force producing means further comprises a piston member movably disposed in said pressure cavity and adapted to exert said sealing force by forcibly engaging said one seal member in response to fluid pressure in said pressure cavity.
Claim 12
Dependent Claim
24 words
Apparatus according to claim 10 wherein said pressure cavity and said piston member are annular and are axially aligned with said one seal member.
Claim 13
Dependent Claim
48 words
Apparatus according to claim 11 wherein said cavity is partially defined by one of said extruder block means and said die block means and said source of fluid pressure comprises an inlet channel defined thereby and communicating with an end of said cavity opposite said one seal member.
Claim 14
Dependent Claim
55 words
Apparatus according to claim 12 including a plurality of spaced apart inner ring seals disposed between a wall of said cavity and an inner wall of said annular piston member and a plurality of spaced apart outer ring seals disposed between a wall of said cavity and an outer wall of said annular piston member.
Claim 15
Dependent Claim
39 words
Apparatus according to claim 13 wherein said block partially defining said cavity further defines a vent orifice terminating between adjacent wall portions of said cavity and said piston member at a position between a pair of said ring seals.
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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) | 1975-08-15 | 1976-02-14 | 1976-08-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-15 | 1980-02-14 | 1980-08-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-15 | 1984-02-14 | 1984-08-15 | $7700.00 | Window Closed / Lapsed |