Patent US4053549A successfully refreshed from Google Patents.
US4053549A
Expired / Lapsed
US
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Method of embossing foam polystyrene to prevent warping upon removal from mold
Assignee: Mobil Oil AS
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Filing: 1975-01-06
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Granted: 1977-10-11
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Expires: 1995-01-06
Abstract
Abstract A method is provided for thermoforming thermoplastic foam articles whereby the tendency for such articles to deform and/or warp immediately upon release from the thermoforming device is eliminated. The method includes the formation of parallel or concentric grooves on one surface of the article during the course of the thermoforming operation. Such grooves eliminate the pronounced tendency of thermoformed articles to curl up following their removal from the thermoforming mold and maintains the formed piece in the desired flat configuration.
Inventors
- 👤 Robert Joseph Vandor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 13:42
CPC Classifications
B; B29; B29C; B29C59/00; B29C59/007; B29C37/00; B29C37/005; B29C44/00; B29C44/34; B29C44/56; B29C44/5627; B29C51/00; B29C59/02; B31; B31F; B31F1/00; B31F1/07; B29C37/0053; B29C37/0057; B29K; B29K2025/00; B29K2105/00; B29K2105/04; B29K2995/00; B29K2995/0037; B29K2995/0094; B29K2995/0096; B31F2201/00; B31F2201/07; B31F2201/0707; B31F2201/0715; B31F2201/0723; B31F2201/0733; B31F2201/0756; B31F2201/0784
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
86 words
In a method of thermoforming a flat foam polystyrene sheet to make a substantially flat article free from integral upstanding wall elements by preheating a flat polystyrene sheet and embossing one side said sheet by pressing said sheet between a pair of mold members, the improvement to eliminate warpage of said article upon removal of said article from said mold members, comprising: forming, by surface embossing at least two spaced apart parallel grooves in a surface of a second side only of the preheated said sheet.
Claim 2
Dependent Claim
86 words
In a method of thermoforming a flat foam polystyrene sheet to make a substantially flat article free from integral upstanding wall elements by preheating a flat polystyrene sheet and embossing one side said sheet by pressing said sheet between a pair of mold members, the improvement to eliminate warpage of said article upon removal of said article from said mold members, comprising: forming, by surface embossing at least two spaced apart parallel grooves in a surface of a second side only of the preheated said sheet.
Claim 3
Dependent Claim
20 words
A method in accordance with claim 1 wherein said parallel grooves extend substantially the complete length of said formed article.
Claim 4
Dependent Claim
18 words
A method in accordance with claim 1 wherein said parallel grooves are in the form of concentric circles.
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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) | 1980-10-10 | 1981-04-11 | 1981-10-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-10-10 | 1985-04-11 | 1985-10-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-10-10 | 1989-04-11 | 1989-10-11 | $7700.00 | Window Closed / Lapsed |