Floating remolding shoes for foam thermoforming molds

In a high-speed thermoforming machine having a pair of platens and at least one pair of matched mold cavities and mold plugs attached thereto, wherein a heat-softened thermoformable sheet is indexed forward an amount that is at least equal to the length of said platens while said mold cavities and said mold plugs are reciprocatingly in open position after producing a first shot of thermoformed articles therebetween, said articles having a selected outside depth, a device for correcting product distortion that shape-preservingly clamps a selected portion of the last row of said thermoformed articles and maintains a selected shape-preserving pressure thereupon until said cavities and plugs have reciprocatively moved apart, comprising:

• A. a remolding cavity which is attached to and disposed beyond one said platen on the forward side thereof;
• B. a remolding shoe which is attached to and disposed beyond the other said platen on the forward side thereof, whereby said selected portion is straddled by said remolding cavity and said remolding shoe when said sheet has been indexed forward by said amount;
• and
• C. a pressure-exerting means for:
• (1) clamping said selected portion between said remolding cavity and said remolding shoe as said cavities and said plugs are reciprocatively closing towards said thermoformable sheet,
• (2) holding said selected portion in the desired shape while the next shot of thermoformed articles are being formed between said cavities and said plugs,
• (3) maintaining said desired shape during a portion of the moving apart of said cavities and said plugs, and
• (4) extending said remolding shoe to a distance that is greater than said outside depth as said thermoformable machine fully opens.

A shape-preserving device for use in combination with a thermoforming molding machine which reciprocatingly thermoforms articles from a heat-softened thermoplastic sheet and thereafter indexes said sheet in a forward direction, said molding machine comprising an upper platen and a lower platen, and said device comprising:

• A. a lateral extension of said upper platen, said extension being disposed in said forward direction;
• B. a lateral extension of said lower platen, said extension being disposed in said forward direction;
• C. a remolding cavity which is formed in one of said lateral extensions;
• and
• D. a remolding shoe assembly which comprises:
• (1) a floating remolding shoe, which conforms to said remolding cavity in shape, less the mold gap designed thereinto,
• (2) a pressure means for pressing said remolding shoe toward said remolding cavity, said pressure means being attached to the other of said lateral extensions, and
• (3) a guide means for slideably aligning said remolding shoe with said remolding cavity while said molding machine is reciprocatingly opening and closing, said guide means being a portion of said other lateral extension.