US3901640A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Expandable forming plug
Assignee: Dow Chemical Co
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Filing: 1973-12-03
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Granted: 1975-08-26
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Expires: 1993-12-03
Abstract
Abstract An expandable forming plug adapted for use in forming apparatus such as plug assisted vacuum or pressure differential forming machines and the like wherein the plug cooperates with a mold to form hollow articles such as containers, closures, trays, and the like, from thermoplastic synthetic resinous film or sheeting. The expandable plug provides hollow articles which during forming can be programed or controlled, as desired, with respect to thickness distribution in the walls thereof and, more particularly, provides hollow articles with side and bottom walls of desired thickness, such as of substantially uniform or of a varying thickness.
Inventors
- 👤 Reuben A Tigner
- 👤 Lewis S Mounts
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 12:01
CPC Classifications
B; B29; B29C; B29C51/00; B29C51/08; B29C33/00; B29C33/44; B29C33/48; B29C33/485; B29C51/04; B29C67/00; B29C43/00; B29C43/32; B29C43/36; B29C43/361; B29C2043/3615; B29C2043/3631; B29C51/10; B29L; B29L2031/00; B29L2031/712; Y; Y10; Y10S; Y10S425/00; Y10S425/014; Y10S425/044
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
109 words
An expandable plug for use in cooperation with a forming mold in apparatus for producing hollow articles from thermoplastic synthetic resinous sheeting or film comprising, a plurality of adjacent elongated pivotal segments, means for holding one end of said segments in a juxtaposed pivotal relationship with each other, means for moving the other opposing ends of said segments outwardly away from one another as said segments advance and force said sheeting or film into said forming mold, means for returning said segments to their original adjacent position as said segments are withdrawn from said forming mold and a flexible, resilient cover or sleeve positioned around said plurality of segments.
Claim 2
Dependent Claim
109 words
An expandable plug for use in cooperation with a forming mold in apparatus for producing hollow articles from thermoplastic synthetic resinous sheeting or film comprising, a plurality of adjacent elongated pivotal segments, means for holding one end of said segments in a juxtaposed pivotal relationship with each other, means for moving the other opposing ends of said segments outwardly away from one another as said segments advance and force said sheeting or film into said forming mold, means for returning said segments to their original adjacent position as said segments are withdrawn from said forming mold and a flexible, resilient cover or sleeve positioned around said plurality of segments.
Claim 3
Dependent Claim
18 words
The expandable plug of claim 1 wherein said flexible, resilient cover or sleeve is made of silicone rubber.
Claim 4
Dependent Claim
28 words
The expandable plug of claim 1 wherein said means for moving other opposing ends of said segments outwardly is a cam that engages camming surfaces of said segments.
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) | 1978-08-25 | 1979-02-24 | 1979-08-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-25 | 1983-02-24 | 1983-08-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-25 | 1987-02-24 | 1987-08-26 | $7700.00 | Window Closed / Lapsed |