US4424183A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Destructible core structure and method for using same
Assignee: Envirotech Pumpsystems Inc
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Filing: 1982-07-06
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Granted: 1984-01-03
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Expires: 2002-07-06
Abstract
Abstract A destructible core is formed from a frangible plastic shell filled with inert ballast. The core is used for forming complex cavities in the production of cast resin parts.
Inventors
- 👤 Mark A. Nelson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 12:11
CPC Classifications
B; B29; B29C; B29C33/00; B29C33/44; B29C33/54; B29C33/0033; B29C39/00; B29C39/22; B29C39/26; B29C39/34; B29K; B29K2067/00; B29K2067/06; B29L; B29L2031/00; B29L2031/748; Y; Y10; Y10S; Y10S264/00; Y10S264/44
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
160 words
A method for producing a cast resinous part with a complex internal cavity, comprising: forming a destructible core structure from a rigid shell configurated as said complex cavity and filled with an inert flowable ballast material; positioning said core structure in the appropriate position within the cavity of a casting mold adapted to produce said cast part, thereby providing a casting space the configuration of said part; introducing casting resin into said casting space, thereby to envelope said core structure, leaving at least one access opening through said cavity space in contact with said core; curing the resin to solidify the resinous mass around said core structure; removing the solidified resinous mass from the mold with the core structure in place; rupturing the shell of said core structure, and removing the ballast material from the shell through said access opening; and removing the shell of the core structure from the internal cavity of the resinous mass through said access opening.
Claim 2
Independent Claim
160 words
A method for producing a cast resinous part with a complex internal cavity, comprising: forming a destructible core structure from a rigid shell configurated as said complex cavity and filled with an inert flowable ballast material; positioning said core structure in the appropriate position within the cavity of a casting mold adapted to produce said cast part, thereby providing a casting space the configuration of said part; introducing casting resin into said casting space, thereby to envelope said core structure, leaving at least one access opening through said cavity space in contact with said core; curing the resin to solidify the resinous mass around said core structure; removing the solidified resinous mass from the mold with the core structure in place; rupturing the shell of said core structure, and removing the ballast material from the shell through said access opening; and removing the shell of the core structure from the internal cavity of the resinous mass through said access opening.
Claim 3
Dependent Claim
87 words
A method according to claim 1 wherein the core structure is formed by coating a thin layer of resin on the inner surfaces of an open top mold which defines the shape of the core structure, filling the coated mold with said ballast material, applying a layer of resin over the ballast material at the open top of the mold to complete the plastic shell around said ballast material, curing the resin to solidify said shell, and removing said shell filled with ballast material from the mold.
Claim 4
Dependent Claim
44 words
A method according to claim 1 wherein the destructible core structure is preformed and comprises a thin plastic shell with an exterior configuration approximately the size and shape of said complex internal cavity and a hollow interior filled with said inert flowable ballast material.
Claim 5
Dependent Claim
12 words
A method according to claim 3 wherein said ballast material is sand.
Claim 6
Dependent Claim
16 words
A method according to claim 3 wherein said plastic shell is constructed from a polyester resin.
Claim 7
Dependent Claim
12 words
A method according to claim 2 wherein said ballast material is sand.
Claim 8
Dependent Claim
16 words
A method according to claim 2 wherein said plastic shell is constructed from a polyester resin.
References Cited (Backward Citations)
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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) | 1987-01-02 | 1987-07-04 | 1988-01-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-01-02 | 1991-07-04 | 1992-01-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-01-02 | 1995-07-04 | 1996-01-03 | $7700.00 | Window Closed / Lapsed |