US3737151A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Injection press
Assignee: Battelle Memorial Institute Inc
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Filing: 1972-02-24
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Granted: 1973-06-05
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Expires: 1992-02-24
Abstract
Abstract In an injection press for thermoplastic material of the type having a heated cylinder containing a feed screw rotatably and axially movably mounted in the cylinder for mixing, pressurizing and feeding the thermoplastic material from a feed hopper to a mould at the opposite end of the feed screw, a restriction at the cylinder end adjacent the mould, the end of the feed screw adjacent the restriction having a shape complementary to the restricted end of the cylinder, the improvement comprising a back pressure adjusting device arranged between a first longitudinal zone of the feed screw for introduction and plasticization of the thermoplastic material and a second zone for degassing the thermoplastic material by means of a degassing opening, and a device for adjusting the axial movement of the feed screw during the plasticization and compression of the thermoplastic material as a function of the pressure in the cylinder zone between its restricted end and the end of the feed screw.
Inventors
- 👤 G Schaeffer
- 👤 J Trub
- 👤 J Bouvet
- 👤 A Kohler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:20
CPC Classifications
B; B29; B29C; B29C45/00; B29C45/17; B29C45/46; B29C45/58; B29C45/60; B29C45/47; B29C45/50; B29C45/76; B29C45/77
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
201 words
In an injection press for thermoplastic material having a cylinder provided at the injection end with a restriction communicating with an injection nozzle, and endless feed screw mounted in the cylinder and having at the injection end a shape complementary to that of the restricted end of the cylinder and having a diameter varying so as to define together with the cylinder successively a first zone for introduction and plasticization of the thermoplastic material, a second zone for degassing the thermoplastic material, and a third zone for compressing the thermoplastic material, the cylinder being provided with a lateral feed opening in the first zone and with a lateral degassing opening in the second zone, a non-return valve arranged at the downstream end of the third zone, cylinder heating means, and means for imparting to the feed screw an angular movement and an axial movement, the improvement comprising a back pressure adjusting device arranged between the first and second zones and a device for adjusting the axial movement of the feed screw during the plasticization and compression of the thermoplastic material as a function of the pressure in the cylinder zone between its restricted end and the end of the feed screw.
Claim 2
Dependent Claim
201 words
In an injection press for thermoplastic material having a cylinder provided at the injection end with a restriction communicating with an injection nozzle, and endless feed screw mounted in the cylinder and having at the injection end a shape complementary to that of the restricted end of the cylinder and having a diameter varying so as to define together with the cylinder successively a first zone for introduction and plasticization of the thermoplastic material, a second zone for degassing the thermoplastic material, and a third zone for compressing the thermoplastic material, the cylinder being provided with a lateral feed opening in the first zone and with a lateral degassing opening in the second zone, a non-return valve arranged at the downstream end of the third zone, cylinder heating means, and means for imparting to the feed screw an angular movement and an axial movement, the improvement comprising a back pressure adjusting device arranged between the first and second zones and a device for adjusting the axial movement of the feed screw during the plasticization and compression of the thermoplastic material as a function of the pressure in the cylinder zone between its restricted end and the end of the feed screw.
Claim 3
Dependent Claim
126 words
An injection press as claimed in claim 1, wherein the device for adjusting the axial movement of the feed screw comprises a pressure detector arranged in the zone between the restricted cylinder end and the screw end, a comparator for comparing the pressure detected by the detector with a reference pressure corresponding to the pressure desired to be maintained in said zone, said comparator being arranged to provide a signal indicative of the difference between the two compared pressures, and a regulator controlled by said signal to act upon said means for axial movement of the feed screw so as to move the latter in the direction and at the speed required to maintain the pressure in said zone at the level of the reference pressure.
Claim 4
Dependent Claim
84 words
An injection press as claimed in claim 2, further comprising control means for adjusting said reference pressure as a function of the level of thermoplastic material in said degassing opening, said control means including a detector mounted on said degassing opening to detect the level of thermoplastic material in the degassing opening and a signal generator having its inlet connected to said detector to provide signals indicative of said level, the outlet of said signal generator being connected to the inlet of said comparator.
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) | 1976-06-04 | 1976-12-04 | 1977-06-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-04 | 1980-12-04 | 1981-06-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-04 | 1984-12-04 | 1985-06-05 | $7700.00 | Window Closed / Lapsed |