Patent US3979494A successfully refreshed from Google Patents.
US3979494A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of perforating thermoplastic film
Assignee: Union Carbide Corp
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Filing: 1975-07-03
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Granted: 1976-09-07
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Expires: 1995-07-03
Abstract
Abstract A plastic film packaging bag is fabricated with directionally tear-prone wicket mounting holes having a hole edge reinforcing bead of plastic selectively thinner in the desired tearing direction formed by a hot gas stream directed through shaped templates holding the bag.
Inventors
- 👤 Alvin E. Ericson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 21:35
CPC Classifications
B; B26; B26F; B26F1/00; B26F1/26; B65; B65B; B65B61/00; B65B61/02; Y; Y10; Y10T; Y10T156/00; Y10T156/10; Y10T156/1052; Y10T156/1056; Y10T428/00; Y10T428/24; Y10T428/24273; Y10T428/24298
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
232 words
A method of making an apexed hole having a varying thickness hole edge perimeter of melted and rehardened plastic in a thermoplastic film sheet material comprising the steps of; masking the thermoplastic film sheet material with a heat resistant masking template having an opening therein of a size and apexed shape substantially congruent with a preselected size and apexed shape of the hole being formed; disposing the thermoplastic film sheet material and the masking template on a backing template having an opening therein of a size and shape substantially similar to the size and shape of the opening in the masking template, the opening in the masking template and the opening in the backing template being juxtaposed in substantially concentric alignment; directing a stream of gas heated to a temperature sufficient to effect rapid melting of the thermoplastic film material into impingement on the masking template and the thermoplastic film sheet material between the openings in the masking template and the backing template for a time sufficient to melt through the thermoplastic film sheet material between said openings, the concentric centerline of said stream being offset epicentrically from the concentric centerline of the juxtaposed openings in the masking and backing templates towards the apex of the hole being formed; removing the stream of gas from impingement on the masking template; and removing the thermoplastic film sheet material from the templates after the
Claim 2
Independent Claim
232 words
A method of making an apexed hole having a varying thickness hole edge perimeter of melted and rehardened plastic in a thermoplastic film sheet material comprising the steps of; masking the thermoplastic film sheet material with a heat resistant masking template having an opening therein of a size and apexed shape substantially congruent with a preselected size and apexed shape of the hole being formed; disposing the thermoplastic film sheet material and the masking template on a backing template having an opening therein of a size and shape substantially similar to the size and shape of the opening in the masking template, the opening in the masking template and the opening in the backing template being juxtaposed in substantially concentric alignment; directing a stream of gas heated to a temperature sufficient to effect rapid melting of the thermoplastic film material into impingement on the masking template and the thermoplastic film sheet material between the openings in the masking template and the backing template for a time sufficient to melt through the thermoplastic film sheet material between said openings, the concentric centerline of said stream being offset epicentrically from the concentric centerline of the juxtaposed openings in the masking and backing templates towards the apex of the hole being formed; removing the stream of gas from impingement on the masking template; and removing the thermoplastic film sheet material from the templates after the
Claim 3
Dependent Claim
37 words
A method according to claim 1 with the added step of redirecting the gas stream, in a direction counter to its initial flow, from the opening in the backing template towards the opening in the masking template.
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) | 1979-09-07 | 1980-03-08 | 1980-09-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-09-07 | 1984-03-08 | 1984-09-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-09-07 | 1988-03-08 | 1988-09-07 | $7700.00 | Window Closed / Lapsed |