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US3729280A Expired / Lapsed US ⏱️ 0.0 years remaining

Injection molding unit

Assignee: Individual
•
Filing: 1970-12-02
•
Granted: 1973-04-24
•
Expires: 1990-12-02
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Abstract

Abstract A method for producing cast pieces from a synthetic material comprises the steps of preplasticizing the synthetic material while the plasticizing cylinder is in communication with the mold cavity, relaxing the preplasticized material to remove the pressure thereon by a limited relative movement between a plasticizing cylinder and a screw conveyer, lifting the plasticizing cylinder away from the mold cavity and out of communication therewith, removing the previously cast piece from the mold cavity, and injecting the material in the plasticizing cylinder through the always open nozzle and into the mold cavity by a stroke of a screw conveyer toward the mold cavity. The apparatus for carrying out this method includes a plasticizing cylinder having a screw conveyer arranged therein. The cylinder and conveyer are mounted for movement relative to one another along the injection axis. Means including a guide member and an abutment are provided for permitting a limited relative movement between the cylinder and screw conveyer.

Inventors

  • 👤 K Hehl

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-27 13:40
CPC Classifications
B; B29; B29C; B29C45/00; B29C45/17; B29C45/46; B29C45/47; B29C45/50; B29C45/5008; B29C45/03; B29C45/07

Claims Analysis

Total Claims: 9
Claim 1
Independent Claim 41 words
An injection unit as defined in claim 1, wherein said guide member is mounted to said supporting bridge and wherein said guided element comprises a rod and said abutment, with said rod and abutment being movably mounted on said suppoRting bridge.
Claim 2
Dependent Claim 36 words
An injection unit as defined in claim 2, wherein said means for mounting said cylinder means includes a pair of supporting struts, and wherein said friction element is adjustably clamped to one of said supporting struts.
Claim 3
Dependent Claim 50 words
An injection unit as defined in claim 3, wherein said rod is a sliding rod to which said abutment is connected, said rod being mounted to said supporting bridge of said screw conveyer so that said abutment will be spaced from said guide member when the preplasticizing step is completed.
Claim 4
Dependent Claim 35 words
An injection unit as defined in claim 4, wherein there are two of said relative movement couplings and two of said friction elements, all of which are symmetrically arranged with respect to the injection axis.
Claim 5
Dependent Claim 40 words
An injection unit as defined in claim 5, further including clamping means for clamping together said friction elements on respective ones of said supporting struts such that the friction between said friction elements in said supporting struts may be varied.
Claim 6
Dependent Claim 40 words
An injection unit as defined in claim 6, further including abutment means mounted on said supporting struts to be adjustable along an axis parallel to the injection axis to limit the movement of said cylinder means along the injection axis.
Claim 7
Dependent Claim 77 words
An injection unit as defined in claim 7, wherein said always open nozzle defines a centrally located bore having an axis, an abutment element having a front surface and arranged on said nozzle toward the casting mold, and a plunger arranged in said bore so as to be axially moveable and non-rotatable therein and dimensioned to extend beyond the front surface of said abutment element when the said cylinder means is in contact with the casting mold.
Claim 8
Dependent Claim 41 words
An injection unit as defined in claim 8, wherein said plunger defines a hollow bore, the cross-sectional area of which arranged toward said cylinder means is less than the cross-sectional area of said screw conveyer means producing the effective injection pressure.
Claim 9
Dependent Claim 84 words
An injection unit as defined in claim 9, wherein said abutment means is arranged on said supporting struts to space said cylinder means from the casting mold, when said cylinder means is in contact with the casting mold, by the distance which said plunger extends beyond the front surface of said abutment element said plunger having two extreme end positions along the injection axis and taking up a center position between its end positions when said cylinder means is at an average operating temperature.

References Cited (Backward Citations)

US3108326A Cited
US3209408A Cited
US3337921A Cited
US3370324A Cited
US3538549A Cited
US3427639A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1976-04-23 1976-10-23 1977-04-24 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1980-04-23 1980-10-23 1981-04-24 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1984-04-23 1984-10-23 1985-04-24 $7700.00 Window Closed / Lapsed

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