US3847525A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for the injection molding of synthetic-resin articles
Assignee: Mannesmann Demag Krauss Maffei GmbH
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Filing: 1971-06-21
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Granted: 1974-11-12
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Expires: 1991-06-21
Abstract
Abstract An injection system for use with injection-molding machines wherein a storage chamber or accumulator is filled with the thermoplastic synthetic resin during the charging of the mold and, during shrinkage of the mass within the mold cavity, the contents of this reservoir are forced into the mold cavity to compensate for such contraction. Subsequent injection-molding operations are carried out as soon as the previous injectionmolding operation is terminated and the shrinkage or contraction of the mass within the previously-charged mold cavity begins.
Inventors
- 👤 F Bielfeldt
- 👤 R Richardsen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:22
CPC Classifications
B; B29; B29C; B29C45/00; B29C45/03; B29C45/12; B29C45/125; B29C45/17; B29C45/46; B29C45/57; B29C45/572; B29C2045/577; Y; Y10; Y10S; Y10S425/00; Y10S425/229
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
274 words
An apparatus for the injection molding of articles from a thermoplastic, comprising: a. a mold assembly having at least one mold cavity; b. mold-closure means connected with said mold assembly for opening and closing said mold assembly and for maintaining same closed with a mold-closing force; c. injector means for charging said mold cavity with the thermoplastic; d. means forming an accumulator communicating with said mold cavity; e. a ram displaceable to feed an accumulated portion of thermoplastic into said mold cavity following contraction of the thermoplastic mass therein after injection of the latter, said mold assembly being formed with a plurality of such mold cavities and said injector means being so constructed and arranged to charge said mold cavities with said thermoplastic in succession, each of said mold cavities being provided with a respective one of such accumulators in communication therewith, and with a respective ram displaceable to feed the respective accumulation of thermoplastic from the respective accumulator into the respective mold; f. flow-blocking means between said injector means and each of said mold cavities for terminating the flow of thermoplastic to the respective mold cavity and enabling the injector means to charge another mold cavity prior to operation of the ram of the former mold cavity, said flow-blocking means including a valve member provided with a recess affording communication between said injector means and said accumulator, each ram being operable independently of the respective valve member, said recess being a circumferential groove formed on said valve member, said valve member being further provided with a passage interconnecting said accumulator and the respective mold cavities in a closed position of said valve member.
Claim 2
Independent Claim
274 words
An apparatus for the injection molding of articles from a thermoplastic, comprising: a. a mold assembly having at least one mold cavity; b. mold-closure means connected with said mold assembly for opening and closing said mold assembly and for maintaining same closed with a mold-closing force; c. injector means for charging said mold cavity with the thermoplastic; d. means forming an accumulator communicating with said mold cavity; e. a ram displaceable to feed an accumulated portion of thermoplastic into said mold cavity following contraction of the thermoplastic mass therein after injection of the latter, said mold assembly being formed with a plurality of such mold cavities and said injector means being so constructed and arranged to charge said mold cavities with said thermoplastic in succession, each of said mold cavities being provided with a respective one of such accumulators in communication therewith, and with a respective ram displaceable to feed the respective accumulation of thermoplastic from the respective accumulator into the respective mold; f. flow-blocking means between said injector means and each of said mold cavities for terminating the flow of thermoplastic to the respective mold cavity and enabling the injector means to charge another mold cavity prior to operation of the ram of the former mold cavity, said flow-blocking means including a valve member provided with a recess affording communication between said injector means and said accumulator, each ram being operable independently of the respective valve member, said recess being a circumferential groove formed on said valve member, said valve member being further provided with a passage interconnecting said accumulator and the respective mold cavities in a closed position of said valve member.
Claim 3
Dependent Claim
276 words
An injection-molding apparatus comprising, in combination: A ram-type injection-molding machine having an outlet through which a charge of synthetic resin is displaceable at an injection pressure in a short of the injection-molding machine; a manifold connected directly to said outlet for receiving said charge and distributing the same to a plurality of manifold branches; a mold assembly having respective mold cavities connected to each of said branches; and a respective valve assembly between each of said branches and the respective mold cavity, each of said valve assemblies comprising: means forming a valve chamber connected to the respective branch and formed with a passage leading to the respective mold cavity, a valve body displaceable toward and away from said passage in said chamber and received therein with all-around clearance, said valve body being formed with a projection of smaller cross-section than the remainder of said body and receivable within the passage upon displacement of said valve member from an unblocking to a blocking position whereby said chamber and the respective branch are disconnected from the respecitve mold cavity, and fluid-operated means for displacing synthetic resin in said chamber against the pressure in said mold into the respective mold cavity just prior to the disposition of said valve member in its blocking position to postinject at least a portion of the synthetic resin in said chamber into the respective mold cavity, each of said valve assemblies further comprising a storage compartment communicating with the respective chamber and receiving synthetic resin of said charge while the respective valve member is in an unblocking position, said fluid-operated means including a ram displaceable in said compartment independently of said valve member.
Claim 4
Dependent Claim
276 words
An injection-molding apparatus comprising, in combination: A ram-type injection-molding machine having an outlet through which a charge of synthetic resin is displaceable at an injection pressure in a short of the injection-molding machine; a manifold connected directly to said outlet for receiving said charge and distributing the same to a plurality of manifold branches; a mold assembly having respective mold cavities connected to each of said branches; and a respective valve assembly between each of said branches and the respective mold cavity, each of said valve assemblies comprising: means forming a valve chamber connected to the respective branch and formed with a passage leading to the respective mold cavity, a valve body displaceable toward and away from said passage in said chamber and received therein with all-around clearance, said valve body being formed with a projection of smaller cross-section than the remainder of said body and receivable within the passage upon displacement of said valve member from an unblocking to a blocking position whereby said chamber and the respective branch are disconnected from the respecitve mold cavity, and fluid-operated means for displacing synthetic resin in said chamber against the pressure in said mold into the respective mold cavity just prior to the disposition of said valve member in its blocking position to postinject at least a portion of the synthetic resin in said chamber into the respective mold cavity, each of said valve assemblies further comprising a storage compartment communicating with the respective chamber and receiving synthetic resin of said charge while the respective valve member is in an unblocking position, said fluid-operated means including a ram displaceable in said compartment independently of said valve member.
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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) | 1977-11-11 | 1978-05-13 | 1978-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-11 | 1982-05-13 | 1982-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-11 | 1986-05-13 | 1986-11-12 | $7700.00 | Window Closed / Lapsed |