US4060226A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for injection molding
Assignee: Individual
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Filing: 1976-07-08
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Granted: 1977-11-29
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Expires: 1996-07-08
Abstract
Abstract A method and apparatus are disclosed for the production of injection molded products from synthetic resinous materials, such as nylon, which tend to be degraded when exposed to oxygen while they are heated to the temperatures required for injection molding. The apparatus includes a barrel having a discharge opening, a screw receiving bore and a vent opening between the feed opening and the discharge opening. A two stage rotatable reciprocable screw is mounted in the bore and includes a vented portion in registry with the vent opening. Water vapor and volatiles are generated during plasticization in the first stage of the screw, and evolve as the material enters the vent section of the second stage. The vapors are exhausted through the vent opening. The vent opening is provided with a check valve which readily permits the exhaust products to pass from the screw receiving bore. However, the check valve effectively prohibits the entrance of atmospheric air through the vent opening to the vent section.
Inventors
- 👤 John Schweller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:25
CPC Classifications
B; B29; B29C; B29C45/00; B29C45/17; B29C45/46; B29C45/58; B29C45/63; B29C45/47; B29C45/50
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
222 words
An injection molding machine for accepting synthetic resinous material degradable when heated and exposed to air, working the material, and forming the material, comprising: a barrel having a material discharge opening, a screw receiving bore communicating with the discharge opening, a feed opening communicating with the screw receiving bore and a vent opening communicating with the screw receiving bore intermediate the feed opening and the discharge opening; screw means mounted in the screw receiving bore, having a first stage upstream of said vent opening and a second stage communicating with the vent opening so that vapor evolved from the material leaving the first stage will discharge through the vent opening; rotary means connected to the screw means and operable to rotate the screw means in the barrel; reciprocatory means connected to the screw means and operable to reciprocate the screw means in the barrel; and check valve means communicating with the vent opening interposed between said vent opening and the atmosphere for blocking flow of air from the atmosphere into said vent, operable to open in response to positive pressure of evolved vapor to exhaust the evolved vapor from the screw receiving bore and operable to close in the absence of positive pressure to substantially exclude flow of air into the bore, so as to avoid contact of air and plasticated material.
Claim 2
Dependent Claim
222 words
An injection molding machine for accepting synthetic resinous material degradable when heated and exposed to air, working the material, and forming the material, comprising: a barrel having a material discharge opening, a screw receiving bore communicating with the discharge opening, a feed opening communicating with the screw receiving bore and a vent opening communicating with the screw receiving bore intermediate the feed opening and the discharge opening; screw means mounted in the screw receiving bore, having a first stage upstream of said vent opening and a second stage communicating with the vent opening so that vapor evolved from the material leaving the first stage will discharge through the vent opening; rotary means connected to the screw means and operable to rotate the screw means in the barrel; reciprocatory means connected to the screw means and operable to reciprocate the screw means in the barrel; and check valve means communicating with the vent opening interposed between said vent opening and the atmosphere for blocking flow of air from the atmosphere into said vent, operable to open in response to positive pressure of evolved vapor to exhaust the evolved vapor from the screw receiving bore and operable to close in the absence of positive pressure to substantially exclude flow of air into the bore, so as to avoid contact of air and plasticated material.
Claim 3
Dependent Claim
16 words
The machine of claim 1 wherein the vent opening is disposed in a generally vertical orientation.
Claim 4
Dependent Claim
16 words
The machine of claim 1 wherein the vent opening is disposed in a generally horizontal orientation.
Claim 5
Dependent Claim
51 words
The machine of claim 1 wherein the check valve means includes: a valve seat encircling the vent opening; and a generally spherical valve element sealingly engaging the valve seat and operable to be lifted from the valve seat in response to pressure generated in the screw receiving bore by evolving vapor.
Claim 6
Dependent Claim
341 words
An injection molding machine for accepting nylon material, working the material, and forming the material, comprising: a barrel having a material discharge opening, a screw receiving bore communicating with the discharge opening, a feed opening communicating with the screw receiving bore and a vent opening communicating with the screw receiving bore intermediate the feed opening and the discharge opening; a screw member mounted in the screw receiving bore and having a first end at the discharge opening that cooperates with the screw receiving bore to define a chamber, a first screw flight in registry with the feed opening and operable with the barrel to accept and work the nylon material, a second screw flight downstream of the first screw flight having a vent region communicating with the vent opening so that vapor evolved from the material will discharge through the vent opening, and valve means downstream of the second screw flight operable to admit material to the chamber during a plasticizing portion of a molding cycle and to inhibit flow of material into the second screw flight from the chamber during an injection portion of the molding cycle; rotary means connected to the screw and operable to rotate the screw in the barrel during the plasticizing portion of the molding cycle; reciprocatory means connected to the screw and operable to advance the screw toward the discharge opening during the injection portion of the molding cycle, to retain the screw at an advanced position during a holding portion of the molding cycle and to assist retraction of the screw from the discharge opening during the plasticizing portion; and check valve means interposed between said vent opening and the atmosphere for blocking the flow of air from the atmosphere into said vent, communicating with the vent opening, operable to open in response to positive pressure of evolved vapor to exhaust the evolved vapor and operable to close in the absence of positive pressure to substantially exclude atmospheric air from the screw receiving bore, so as to avoid contact of air and plasticated material.
Claim 7
Dependent Claim
341 words
An injection molding machine for accepting nylon material, working the material, and forming the material, comprising: a barrel having a material discharge opening, a screw receiving bore communicating with the discharge opening, a feed opening communicating with the screw receiving bore and a vent opening communicating with the screw receiving bore intermediate the feed opening and the discharge opening; a screw member mounted in the screw receiving bore and having a first end at the discharge opening that cooperates with the screw receiving bore to define a chamber, a first screw flight in registry with the feed opening and operable with the barrel to accept and work the nylon material, a second screw flight downstream of the first screw flight having a vent region communicating with the vent opening so that vapor evolved from the material will discharge through the vent opening, and valve means downstream of the second screw flight operable to admit material to the chamber during a plasticizing portion of a molding cycle and to inhibit flow of material into the second screw flight from the chamber during an injection portion of the molding cycle; rotary means connected to the screw and operable to rotate the screw in the barrel during the plasticizing portion of the molding cycle; reciprocatory means connected to the screw and operable to advance the screw toward the discharge opening during the injection portion of the molding cycle, to retain the screw at an advanced position during a holding portion of the molding cycle and to assist retraction of the screw from the discharge opening during the plasticizing portion; and check valve means interposed between said vent opening and the atmosphere for blocking the flow of air from the atmosphere into said vent, communicating with the vent opening, operable to open in response to positive pressure of evolved vapor to exhaust the evolved vapor and operable to close in the absence of positive pressure to substantially exclude atmospheric air from the screw receiving bore, so as to avoid contact of air and plasticated material.
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) | 1980-11-28 | 1981-05-30 | 1981-11-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-11-28 | 1985-05-30 | 1985-11-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-11-28 | 1989-05-30 | 1989-11-29 | $7700.00 | Window Closed / Lapsed |