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US 5,237,796 AGranted
Method and apparatus for differential softening of thermoformable plastic
AssigneeForma-Pack, L.P.
InventorLorne Bonkowski
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AssigneeForma-Pack, L.P.
InventorLorne Bonkowski
Estimating the term…
The present invention provides a method and apparatus for differentially softening plastic used to package articles. Select areas of the sheet are selectively softened by treating those areas to allow either increased or decreased softening of the sheet in response to radiation absorption. The treatment can include the application of coating materials to the select areas or the lamination of different types of plastics. In the illustrated embodiment, heat is applied to the sheet by use of a infrared radiation source. Either before or after the sheet has been softened in the areas, the sheet is positioned adjacent to a forming plate for stretch forming the sheet. The plate causes the softened areas of the sheet, along with any unsoftened areas bordering the softened areas, to be drawn and stretched over and around the surface of the article intended to be covered or held. The softened portions of the sheet are then allowed to cool to their unsoftened, relatively rigid state, resulting in a carrier that covers the top and sides of each article.
A method of forming a carrier for carrying a plurality of articles, the method comprising the steps of:
A method of forming a carrier for carrying a plurality of articles, the method comprising the steps of:
A method of forming a carrier for carrying a plurality of articles, the method comprising the steps of:
A method of forming a carrier for carrying a plurality of articles, the method comprising the steps of:
Dependencies are inferred from the claim text.