US3728062A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Forming articles from sheet material
Assignee: Monsanto Co
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Filing: 1970-04-02
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Granted: 1973-04-17
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Expires: 1990-04-02
Abstract
Abstract In a trim in place thermoforming process for shaping articles from sheet material wherein a blade penetrates the sheet around the periphery of each article to facilitate later removal, method and apparatus improvements wherein limited portions of the leading surface of the blade are introduced into the sheet to a lesser extent than that of the remainder of the leading surface to form frangible tabs in the sheet adjacent side portions of the article which extend in the direction of sheet advancement, thereby reducing the criticality of the sheet thickness along the line of penetration for retaining the articles attached to the sheet. To form the tabs, the leading surface of the blade has indentations therein which are preferably oriented at an acute angle to the adjoining surface of the article being formed, as opposed to the adjoining surface of the portion of the sheet remaining after the article is removed.
Inventors
- 👤 L Layman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:38
CPC Classifications
B; B29; B29C; B29C51/00; B29C51/26; B29C51/30; B29C51/32; B26; B26D; B26D7/00; B26D7/08; B26D7/10; B26F; B26F1/00; B26F1/18; B26F1/22
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
251 words
In a trim in place, thermoforming apparatus for repeatedly forming packaging containers from heated portions of a thermoplastic sheet being advanced through the apparatus which includes a container mold having sides extending in the direction of sheet advancement, means for forcing each heated sheet portion into said mold to form the containers, means surrounding said mold for sealing each heated sheet portion against an opposing rigid surface prior to forming and for penetrating the sheet around the periphery of each formed container along the line of prior sealing to form a line of penetration therein and means for advancing each heated sheet portion with the container attached therein across a stripping surface to break each container away from each heated sheet portion along the line of penetration, the improvement wherein the means for sealing and penetrating is a blade having surfaces spaced from each other defining its thickness, one of the blade surfaces being situated adjacent said mold sides, said blade having a leading thickness surface with shaped depressions formed therein which increase in depth across the thickness in a direction from the surface of the blade adjacent said mold sides to the other thickness defining blade surface whereby to form frangible tabs in said sheet abutting the periphery of a container during formation of said line of penetration, the thickness of said tabs as a result of the varying depth of the depressions being less at their joint with the container than at that with the remainder of the sheet.
Claim 2
Dependent Claim
251 words
In a trim in place, thermoforming apparatus for repeatedly forming packaging containers from heated portions of a thermoplastic sheet being advanced through the apparatus which includes a container mold having sides extending in the direction of sheet advancement, means for forcing each heated sheet portion into said mold to form the containers, means surrounding said mold for sealing each heated sheet portion against an opposing rigid surface prior to forming and for penetrating the sheet around the periphery of each formed container along the line of prior sealing to form a line of penetration therein and means for advancing each heated sheet portion with the container attached therein across a stripping surface to break each container away from each heated sheet portion along the line of penetration, the improvement wherein the means for sealing and penetrating is a blade having surfaces spaced from each other defining its thickness, one of the blade surfaces being situated adjacent said mold sides, said blade having a leading thickness surface with shaped depressions formed therein which increase in depth across the thickness in a direction from the surface of the blade adjacent said mold sides to the other thickness defining blade surface whereby to form frangible tabs in said sheet abutting the periphery of a container during formation of said line of penetration, the thickness of said tabs as a result of the varying depth of the depressions being less at their joint with the container than at that with the remainder of the sheet.
Claim 3
Dependent Claim
34 words
The apparatus of claim 1 wherein the surfaces of the depressions providing said decrease in depth form an angle of from 20* to 60* with the surface of the blade adjacent said mold sides.
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) | 1976-04-16 | 1976-10-16 | 1977-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-16 | 1980-10-16 | 1981-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-16 | 1984-10-16 | 1985-04-17 | $7700.00 | Window Closed / Lapsed |