Patent US3710987A successfully refreshed from Google Patents.
US3710987A
Expired / Lapsed
US
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Injection molding machine for thermo-setting plastics
Assignee: Kawasaki Hydromechanics Corp
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Filing: 1971-04-15
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Granted: 1973-01-16
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Expires: 1991-04-15
Abstract
Abstract In the injection molding of thermosetting plastic the tendency of the plastic to harden in the injection cylinder can be successfully reduced, according to the invention, by minimizing the frictional engagement of the plunger with the bearing member therefore and incorporating appropriate fluid passage means in the plunger and the bearing member so as to prevent any overheating of the thermosetting plastic in the injection cylinder. Annular weir means formed on the cylinder wall serves to cause fluidal motion of the plastic uniform throughout the entire cylinder space, preventing any undesirable temperature gradient therein.
Inventors
- 👤 M Bessho
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:27
CPC Classifications
B; B29; B29C; B29C45/00; B29C45/17; B29C45/46; B29C45/53
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
187 words
An injection molding machine, for thermosetting plastics, of the type including an injection cylinder, a plunger slidably fitted in said injection cylinder, and an injection nozzle fixed to one end of said injection cylinder, characterized in that the plunger has an outer diameter substantially smaller than the internal diameter of the injection cylinder to define an annular space of an appropriate size between the plunger and the internal wall of the injection cylinder, that an annular packing member formed of elastic material is fitted in the base end portion of the injection cylinder for slidable fitting engagement with the peripheral surface of the plunger and is formed at the inner end with an externally conical lip yieldabLe under the pressure of the plastic material fed in the injection cylinder to closely seal the peripheral surface of the plunger, and said injection cylinder being formed on the internal wall thereof with an annular recess communicating with a resin inlet port formed in the cylinder wall at the feed end of said injection cylinder, and with an annular weir adjoining to said annular recess on the downstream side thereof.
Claim 2
Dependent Claim
187 words
An injection molding machine, for thermosetting plastics, of the type including an injection cylinder, a plunger slidably fitted in said injection cylinder, and an injection nozzle fixed to one end of said injection cylinder, characterized in that the plunger has an outer diameter substantially smaller than the internal diameter of the injection cylinder to define an annular space of an appropriate size between the plunger and the internal wall of the injection cylinder, that an annular packing member formed of elastic material is fitted in the base end portion of the injection cylinder for slidable fitting engagement with the peripheral surface of the plunger and is formed at the inner end with an externally conical lip yieldabLe under the pressure of the plastic material fed in the injection cylinder to closely seal the peripheral surface of the plunger, and said injection cylinder being formed on the internal wall thereof with an annular recess communicating with a resin inlet port formed in the cylinder wall at the feed end of said injection cylinder, and with an annular weir adjoining to said annular recess on the downstream side thereof.
References Cited (Backward Citations)
US3006413A
Cited
US2213699A
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US2587930A
Cited
US2795195A
Cited
GB799672A
Cited
FR1181018A
Cited
US3231656A
Cited
US3357706A
Cited
US3457606A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-01-16 | 1976-07-17 | 1977-01-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-16 | 1980-07-17 | 1981-01-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-16 | 1984-07-17 | 1985-01-16 | $7700.00 | Window Closed / Lapsed |