US3787159A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for injection molding with thermosetting resins
Assignee: Eckert and Ziegler GmbH
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Filing: 1971-05-03
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Granted: 1974-01-22
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Expires: 1991-05-03
Abstract
Abstract A thermosetting resin is injected into a partially open separable mold having a mold cavity. This mold is then partially closed to precompress the resin and is heated to soften it. After a predetermined amount of time, the mold is fully closed to compress the mass of resin and to force it into every portion of the cavity. A telescoping mold and a valve between the mold and the injection head are used to prevent the mass from escaping during compression.
Inventors
- 👤 F Bielfeldt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:04
CPC Classifications
B; B29; B29C; B29C45/00; B29C45/17; B29C45/46; B29C45/56; B29C45/561; B29C2045/5625
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
201 words
An apparatus for molding a synthetic-resin article of predetermined volume and configuration, said apparatus comprising: a separable mold having a mold cavity of, in a fully closed condition of said mold, said volume and configuration, said mold having a pair of telescopingly interfitting mold halves; injection means for forcing under pressure a mass of flowable thermosetting synthetic-resin material of said predetermined volume into said cavity; means for heating said mold; control means connected to said mold and to said heating means for relatively displacing said mold halves to less than a fully closed initial condition wherein the two halves are held apart with a gap and define a completely enclosed cavity with a volume greater than said predetermined volume during injection of said mass thereinto, heating said mold in said initial condition, thereafter relatively displacing said mold halves to decrease said gap and compress the heated mass confined in the cavity, and ultimately displacing said mold halves to eliminate said gap in a final condition ; and valve means operatively connected to said control means and interposed between said injection means and said mold for blocking fluid flow between them in and between said initial and final condition of said mold.
Claim 2
Independent Claim
201 words
An apparatus for molding a synthetic-resin article of predetermined volume and configuration, said apparatus comprising: a separable mold having a mold cavity of, in a fully closed condition of said mold, said volume and configuration, said mold having a pair of telescopingly interfitting mold halves; injection means for forcing under pressure a mass of flowable thermosetting synthetic-resin material of said predetermined volume into said cavity; means for heating said mold; control means connected to said mold and to said heating means for relatively displacing said mold halves to less than a fully closed initial condition wherein the two halves are held apart with a gap and define a completely enclosed cavity with a volume greater than said predetermined volume during injection of said mass thereinto, heating said mold in said initial condition, thereafter relatively displacing said mold halves to decrease said gap and compress the heated mass confined in the cavity, and ultimately displacing said mold halves to eliminate said gap in a final condition ; and valve means operatively connected to said control means and interposed between said injection means and said mold for blocking fluid flow between them in and between said initial and final condition of said mold.
References Cited (Backward Citations)
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Cited
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Cited
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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) | 1977-01-21 | 1977-07-23 | 1978-01-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-21 | 1981-07-23 | 1982-01-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-21 | 1985-07-23 | 1986-01-22 | $7700.00 | Window Closed / Lapsed |