Method and apparatus for forming twin sheet hollow plastic articles
First Claim
1. A method of forming a twin sheet hollow plastic article comprising:
- providing a heating station;
providing a hot forming station having first and second coacting molds;
providing a cold forming station having first and second coating molds;
providing first and second plastic sheets;
heating the sheets at the heating station;
thereafter moving the sheets to the hot forming station;
at the hot forming station molding the first and second sheets to the first and second hot forming molds respectively;
bringing the hot forming molds together to selectively fuse the first and second sheets together and form a twin sheet hollow plastic article;
thereafter opening the first and second hot forming molds and moving the article to the cold forming station; and
at the cold forming station moving the first and second cold forming molds together and into respective engagement with the twin sheet hollow plastic article.
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Accused Products
Abstract
A pair of plastic sheets is loaded directly into a pair of clamping frames. The sheets are then moved in the clamping frames into an oven where the sheets are heated, whereafter the sheets are transferred to a hot forming station where the sheets are formed into a pallet. This pallet is then transferred to a cold forming station where further processing of the pallet takes place, and then to an unloading station where the finished pallet is removed and a new set of plastic sheets is loaded into the clamping frames. At the hot forming station the sheets are delivered in side by side relation with one sheet overlying a female mold and the other sheet underlying a male mold, the sheets are molded respectively and simultaneously to the male and female molds, the female mold is shifted laterally to a position underlying the male mold, and the molds are brought together to fuse selected portions of the sheets together to form the twin sheet pallet. The cold forming station includes male and female molds, corresponding generally to the male and female molds of the hot forming station, which reengage the pallet and provide further forming and curing of the pallet as a new pallet is formed at the hot forming station.
40 Citations
8 Claims
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1. A method of forming a twin sheet hollow plastic article comprising:
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providing a heating station; providing a hot forming station having first and second coacting molds; providing a cold forming station having first and second coating molds; providing first and second plastic sheets; heating the sheets at the heating station; thereafter moving the sheets to the hot forming station; at the hot forming station molding the first and second sheets to the first and second hot forming molds respectively; bringing the hot forming molds together to selectively fuse the first and second sheets together and form a twin sheet hollow plastic article; thereafter opening the first and second hot forming molds and moving the article to the cold forming station; and at the cold forming station moving the first and second cold forming molds together and into respective engagement with the twin sheet hollow plastic article. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification