US4722678A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rotational mold with valved charge box
Assignee: Ex-Cell-O Corp
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Filing: 1987-03-16
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Granted: 1988-02-02
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Expires: 2007-03-16
Abstract
Abstract Apparatus for manufacturing thin walled hollow parts such as automobile crash pads from dry thermoplastic powder includes a louver type valve system in the open end of a powder charge box and means for joining the charge box end-to-end with an open-ended heated mold for rotation so that the charge box will be inverted above the mold at the end of an upward swing movement during which the valve is closed to prevent flow of powder to the mold. Once the charge box is fully inverted the valve is opened to evenly distribute the powder into the mold by gravity flow to prevent excessive build-up of wall thickness on the mold surfaces.
Inventors
- 👤 John M. Wersosky
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 07:11
CPC Classifications
B; B29; B29C; B29C41/00; B29C41/34; B29C41/36; B29C41/02; B29C41/18; B29L; B29L2031/00; B29L2031/30
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
150 words
Apparatus for molding a thin-walled hollow plastic part in a heated open-ended mold from a charge of thermoplastic powder material in an open-ended charge box comprising: means for joining a heated mold and charge box in open-ended relationship; means for rotating the joined mold and charge box together so as to locate the charge box in vertical overlying relationship to the open end of the heated mold; valve means operative during said prededing rotation to hold the powder charge in the charge box until the open end thereof is in full vertical overlying relationship to the open end of the heated mold; and means for operating said valve means to cause the powder charge to flow by gravity evenly through the full width and length of the open end of the mold so as to produce a uniform build-up of a skin of desired shape and size on the mold.
Claim 2
Dependent Claim
150 words
Apparatus for molding a thin-walled hollow plastic part in a heated open-ended mold from a charge of thermoplastic powder material in an open-ended charge box comprising: means for joining a heated mold and charge box in open-ended relationship; means for rotating the joined mold and charge box together so as to locate the charge box in vertical overlying relationship to the open end of the heated mold; valve means operative during said prededing rotation to hold the powder charge in the charge box until the open end thereof is in full vertical overlying relationship to the open end of the heated mold; and means for operating said valve means to cause the powder charge to flow by gravity evenly through the full width and length of the open end of the mold so as to produce a uniform build-up of a skin of desired shape and size on the mold.
Claim 3
Dependent Claim
78 words
In the apparatus of claim 1, said valve means including a plurality of louvers, means in association with said louvers for forming a sealed overlapping barrier against passage of powder from the charge box; and means for aligning said louvers in spaced, aprallel relationship to form a plurality of powder flow paths for even, vertical gravity flow of powder from the box from side-to-side and end-to-end of the open end of the mold during a thermoplastic fill step.
Claim 4
Dependent Claim
248 words
Apparatus for molding a thin-walled hollow plastic part in a heated open-ended mold from a charge of thermoplastic powder material in an open-ended charge box comprising: means for joining a heated mold and charge box in open-ended relationship; means for rotating the joined mold and charge box together so as to locate the charge box in vertical overlying relationship to the open end of the heated mold; valve means positioned substantially along the entire length of the charge box operative during said preceding rotation to hold the powder charge in the charge box until the open end thereof is in full vertical overlying relationship to the open end of the heated mold; means for operating said valve means to cause the powder charge to flow by gravity evenly through the full width and length of the open end of the mold so as to produce a uniform build-up of a skin of desired shape and size on the mold; said means for rotating reinverting the joined mold and charge box with the valve in an opened position so that the mold is disposed vertically above the charge box; air sweep means located on said charge box directing air jets against loosely adherent powder on the mold surface for releasing such powder for gravity return to the charge box through the open valve means; and vacuum means to maintain a negative pressure in said charge box to prevent over pressurization and expulsion of returned powder from said charge box.
Claim 5
Dependent Claim
248 words
Apparatus for molding a thin-walled hollow plastic part in a heated open-ended mold from a charge of thermoplastic powder material in an open-ended charge box comprising: means for joining a heated mold and charge box in open-ended relationship; means for rotating the joined mold and charge box together so as to locate the charge box in vertical overlying relationship to the open end of the heated mold; valve means positioned substantially along the entire length of the charge box operative during said preceding rotation to hold the powder charge in the charge box until the open end thereof is in full vertical overlying relationship to the open end of the heated mold; means for operating said valve means to cause the powder charge to flow by gravity evenly through the full width and length of the open end of the mold so as to produce a uniform build-up of a skin of desired shape and size on the mold; said means for rotating reinverting the joined mold and charge box with the valve in an opened position so that the mold is disposed vertically above the charge box; air sweep means located on said charge box directing air jets against loosely adherent powder on the mold surface for releasing such powder for gravity return to the charge box through the open valve means; and vacuum means to maintain a negative pressure in said charge box to prevent over pressurization and expulsion of returned powder from said charge box.
Claim 6
Dependent Claim
78 words
In the apparatus of claim 3, said valve means including a plurality of louvers, means in association with said louvers for forming a sealed overlapping barrier against passage of powder from the charge box; and means for aligning said louvers in spaced, parallel relationship to form a plurality of powder flow paths for even, vertical gravity flow of powder from the box from side-to-side and end-to-end of the open end of the mold during a thermoplastic fill step.
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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) | 1991-02-01 | 1991-08-03 | 1992-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-02-01 | 1995-08-03 | 1996-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-02-01 | 1999-08-03 | 2000-02-02 | $7700.00 | Window Closed / Lapsed |