Patent US4776996A successfully refreshed from Google Patents.
US4776996A
Expired / Lapsed
US
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Process and apparatus for forming hollow structures from powdered thermoplastic materials
Assignee: FIBER TECHNOLOGY Corp A CORP OF UT
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Filing: 1984-08-16
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Granted: 1988-10-11
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Expires: 2004-08-16
Abstract
Abstract A process is disclosed for forming a thermoplastic structure on the exterior surface of the heated mold form. A mold is heated to approximately two times the melting temperature of a thermoplastic material and particulate thermoplastic material then sprinkled onto the exterior surface of the heated mold. An adhesively bondable material may then be added to the semi-molten thermoplastic material structure. The mold is then cooled and the resulting thermoplastic structure removed. An apparatus for practicing the above process comprising a mold form, heating system, and particulate thermoplastic material dispensing system is also disclosed.
Inventors
- 👤 Larry Ashton
- 👤 Roland J. Christensen
- 👤 Randy L. Crane
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 15:14
CPC Classifications
B; B29; B29C; B29C41/00; B29C41/02; B29C41/08; B29C41/085; B29C33/00; B29C33/02; B29C33/04; B29C41/34; B29C41/46; B29K; B29K2105/00; B29K2105/25; B29K2105/251
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
79 words
A method for forming a hollow structure, comprising: a. heating and rotating a mold; b. depositing powdered thermoplastic material onto the outer surface of said heated rotating mold to form on said outer surface a semi-molten layer of said thermoplastic material; and c. depositing an adhesively bindable material onto the outer surface of said semi-molten thermoplastic layer, said material consisting of glass or graphite fibers or microballoons, said bindable material enhancing the adhesive bonding characteristics of the resultant structure.
Claim 2
Independent Claim
79 words
A method for forming a hollow structure, comprising: a. heating and rotating a mold; b. depositing powdered thermoplastic material onto the outer surface of said heated rotating mold to form on said outer surface a semi-molten layer of said thermoplastic material; and c. depositing an adhesively bindable material onto the outer surface of said semi-molten thermoplastic layer, said material consisting of glass or graphite fibers or microballoons, said bindable material enhancing the adhesive bonding characteristics of the resultant structure.
Claim 3
Dependent Claim
36 words
The method of claim 1 wherein step c is continued until a plurality of layers having a composite thickness to length ratio of approximately one to two thousand have been deposited on said rotating heated mold.
Claim 4
Independent Claim
150 words
A method for forming a hollow structure from a powdered thermoplastic material, comprising the steps of: a. applying a coating of release agent to a mold form and heating the mold form to at least the melting point of said thermoplastic material; b. rotating said heated mold form; c. sprinkling said powdered thermoplastic material onto the exterior of said heated rotating mold form to form a semi-molten layer of said material on said mold; d. inspecting said layer of material for defects while still in the semi-molten state and correcting such defects by selectively adding additional powdered thermoplastic material in the defect areas; e. sprinkling an adhesively bindable material onto the outer surface of said semi-molten layer, said material consisting of glass or graphite fibers or microballoons; f. cooling said mold form to effectuate hardening of said layer; and g. removing the resulting formed hollow structure from said mold form.
Claim 5
Independent Claim
150 words
A method for forming a hollow structure from a powdered thermoplastic material, comprising the steps of: a. applying a coating of release agent to a mold form and heating the mold form to at least the melting point of said thermoplastic material; b. rotating said heated mold form; c. sprinkling said powdered thermoplastic material onto the exterior of said heated rotating mold form to form a semi-molten layer of said material on said mold; d. inspecting said layer of material for defects while still in the semi-molten state and correcting such defects by selectively adding additional powdered thermoplastic material in the defect areas; e. sprinkling an adhesively bindable material onto the outer surface of said semi-molten layer, said material consisting of glass or graphite fibers or microballoons; f. cooling said mold form to effectuate hardening of said layer; and g. removing the resulting formed hollow structure from said mold form.
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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) | 1991-10-11 | 1992-04-11 | 1992-10-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-10-11 | 1996-04-11 | 1996-10-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-10-11 | 2000-04-11 | 2000-10-11 | $7700.00 | Window Closed / Lapsed |