Patent US3746497A successfully refreshed from Google Patents.
US3746497A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for making articles of manufacture from a thin film of plastic
Assignee: Standard Oil Co
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Filing: 1971-04-08
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Granted: 1973-07-17
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Expires: 1991-04-08
Abstract
Abstract Disclosed is an improved thermoforming process wherein the amount of plastic film forced into a mold cavity is restricted so that only the proper amount required is introduced into the cavity. The restricting step may be achieved by (1) clamping the film at the open mouth of the cavity and then forcing film into the cavity or (2) heating only those portions of the film which are needed to properly fill the cavity or (3) heating the film uniformly and then selectively cooling those portions of the film which should not be introduced into the cavity. Novel clamping apparatus is also disclosed.
Inventors
- 👤 P Neil
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 13:20
CPC Classifications
B; B29; B29C; B29C51/00; B29C51/26; B29C51/261; B29C51/262; B29C51/04; B29C51/42; B29C51/421; B29C51/422; B29C51/10
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
212 words
Apparatus for making an article of manufacture from a thin film of plastic, comprising a first section including a female mold cavity therein having an open mouth circumscribed by a first clamping member spaced from and larger than the open mouth but of the same general configuration as the open mouth, and a second section including a male plug assist adapted to fit into said female mold cavity, and seal means near the perimeter of said second section, said first and second sections being adapted to move together; and movable clamping plate means disposed between said first and second sections and including an opening which permits the plug assist to pass therethrough, a second clamping member larger than the opening and having a configuration substantially the same as the configuration of the first clamping member so that the film can be claMped between said first and second members when the first and second sections move together and, at the perimeter of the plate means, a clamping element adapted to engage a thin film of plastic overlying the first section, said clamping element clamping the film near the perimeter of the first section, with the seal means engaging the underside of the clamping plate when said first and second sections are moved together.
Claim 2
Dependent Claim
212 words
Apparatus for making an article of manufacture from a thin film of plastic, comprising a first section including a female mold cavity therein having an open mouth circumscribed by a first clamping member spaced from and larger than the open mouth but of the same general configuration as the open mouth, and a second section including a male plug assist adapted to fit into said female mold cavity, and seal means near the perimeter of said second section, said first and second sections being adapted to move together; and movable clamping plate means disposed between said first and second sections and including an opening which permits the plug assist to pass therethrough, a second clamping member larger than the opening and having a configuration substantially the same as the configuration of the first clamping member so that the film can be claMped between said first and second members when the first and second sections move together and, at the perimeter of the plate means, a clamping element adapted to engage a thin film of plastic overlying the first section, said clamping element clamping the film near the perimeter of the first section, with the seal means engaging the underside of the clamping plate when said first and second sections are moved together.
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) | 1976-07-16 | 1977-01-15 | 1977-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-16 | 1981-01-15 | 1981-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-16 | 1985-01-15 | 1985-07-17 | $7700.00 | Window Closed / Lapsed |