US4034054A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for thermoforming hollow articles
Assignee: Rexam Beverage Can Co
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Filing: 1974-09-20
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Granted: 1977-07-05
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Expires: 1994-09-20
Abstract
Abstract There is disclosed a novel process for using a pressure box assembly associated with a thermoplastic thermoforming assembly. The pressure box assembly is provided with a diaphram formed of a resilient material, such as synthetic rubber and the like, disposed across the entrance into a cavity of the pressure box of the pressure box assembly. The pressure box assembly is associated with thermoforming molding apparatus to cause a heat thermoplastic sheet or web to be drawn about a male mold provided on a male mold assembly during insertion of the male mold into the cavity in a hollow article of more uniform wall thickness.
Inventors
- 👤 Donald G. Sauer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 01:19
CPC Classifications
B; B29; B29C; B29C51/00; B29C51/26; B29C51/28; B29C51/04; B29C43/00; B29C43/02; B29C43/10; B29C43/12; B29C51/10
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
151 words
In a process for thermoforming a hollow plastic article from a sheet of heated thermoplastic material over a male mold contained to a desired internal shape of said article, wherein said sheet of thermoplastic material is firmly held between a pressure box assembly and a male mold assembly including said male mold, the improvement comprising: (a) closing an entrance to a chamber of said pressure box by disposing a resilient diaphragm of elastomeric material across said entrance, between said sheet and said entrance; (b) stretching and forming said sheet by moving and pressing said male mold against a side of said sheet opposite said diaphragm, said moving including passing said male mold through a plane originally occupied by said diaphragm so that said resilient diaphragm causes said sheet to be drawn about said male mold, and maintaining chamber at a positive pressure with a compressible fluid during said stretching and forming.
Claim 2
Dependent Claim
151 words
In a process for thermoforming a hollow plastic article from a sheet of heated thermoplastic material over a male mold contained to a desired internal shape of said article, wherein said sheet of thermoplastic material is firmly held between a pressure box assembly and a male mold assembly including said male mold, the improvement comprising: (a) closing an entrance to a chamber of said pressure box by disposing a resilient diaphragm of elastomeric material across said entrance, between said sheet and said entrance; (b) stretching and forming said sheet by moving and pressing said male mold against a side of said sheet opposite said diaphragm, said moving including passing said male mold through a plane originally occupied by said diaphragm so that said resilient diaphragm causes said sheet to be drawn about said male mold, and maintaining chamber at a positive pressure with a compressible fluid during said stretching and forming.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-07-04 | 1981-01-03 | 1981-07-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-04 | 1985-01-03 | 1985-07-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-04 | 1989-01-03 | 1989-07-05 | $7700.00 | Window Closed / Lapsed |