Sheet support apparatus
First Claim
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1. Differential pressure thermoforming apparatus for forming articles in a continuous sheet of thermoplastic material comprising:
- a frame having a longitudinally forward end and a rearward end;
laterally spaced apart sheet supporting means movably mounted on said frame for supporting the lateral edges of said sheet and for incrementally longitudinally forwardly indexing said continuous sheet of thermoplastic material relative to said frame in a forward, longitudinal path of travel;
mold means mounted on said frame (disposed) in juxtaposition with said sheet supporting means for forming articles in the sheet supported thereon;
said mold means being movable forward and away from said sheet between a retract position and a sheet engaging position;
heating means, disposed on said frame upstream of said mold means for heating said sheet to forming temperature; and
means, stationarily mounted on said frame upstream of said mold means, for upwardly directing pressurized fluid between said sheet supporting means to support the midportion of said heated sheet upstream of said mold means at a level spaced from the level of said mold means in said retract position and inhibit sagging of the midportion of said sheet under its own weight as said sheet moves relative thereto from said heating means to said mold means.
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Abstract
Sheet supporting apparatus for a continuous sheet, differential pressure thermoforming machine comprising laterally spaced apart sheet support members for supporting the lateral edges of a formable sheet and for moving the sheet in a forward path of travel. The apparatus includes an open top, air receiving, sheet support box disposed interjacent the laterally spaced sheet support members upstream of a differential pressure mold, and mechanism for introducing air under pressure to the inside of the box for supporting a midportion of the sheet of plastic.
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Citations
11 Claims
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1. Differential pressure thermoforming apparatus for forming articles in a continuous sheet of thermoplastic material comprising:
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a frame having a longitudinally forward end and a rearward end; laterally spaced apart sheet supporting means movably mounted on said frame for supporting the lateral edges of said sheet and for incrementally longitudinally forwardly indexing said continuous sheet of thermoplastic material relative to said frame in a forward, longitudinal path of travel; mold means mounted on said frame (disposed) in juxtaposition with said sheet supporting means for forming articles in the sheet supported thereon; said mold means being movable forward and away from said sheet between a retract position and a sheet engaging position; heating means, disposed on said frame upstream of said mold means for heating said sheet to forming temperature; and means, stationarily mounted on said frame upstream of said mold means, for upwardly directing pressurized fluid between said sheet supporting means to support the midportion of said heated sheet upstream of said mold means at a level spaced from the level of said mold means in said retract position and inhibit sagging of the midportion of said sheet under its own weight as said sheet moves relative thereto from said heating means to said mold means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. Differential pressure thermoforming apparatus for forming articles in a continuous sheet of thermoplastic material comprising:
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a frame having a longitudinal forward end and a rearward end; heating means, disposed on said frame, for heating a portion of said sheet to forming temperature; mold means, mounted on said frame downstream of said heating means, for differential pressure forming articles in the heated portion of said sheet at a mold station; said mold means being movable between a retract position and a sheet engaging position; laterally spaced apart sheet supporting means movably mounted on said frame, for supporting the lateral edges of said sheet and for incrementally longitudinally forwardly indexing said continuous sheet relative to said frame in a forward, longitudinal path of travel to successively move said sheet from said heating means to said mold station; and means, stationarily mounted on said frame upstream of said mold means, for upwardly directing pressurized fluid between said sheet supporting means toward the midportion of said sheet between said sheet support means to support the midportion of said heated sheet upstream of said mold means at a level spaced from the level of said mold means in said retract position and inhibit sagging of said sheet midportion under its own weight as said sheet moves relative thereto from said heating means to said mold means.
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10. Differential pressure thermoforming apparatus for forming articles in a continuous sheet of thermoplastic material comprising:
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a frame having a longitudinally forward end and a rearward end; heating means mounted on said frame for heating said sheet to forming temperature; mold means, mounted on said frame for movement between retract and mold positions, for differential pressure forming articles in the heated sheet; billowing means, mounted on said frame upstream of said mold means, for upwardly billowing a portion of said continuous sheet disposed between said heating means and said mold means; laterally spaced apart, sheet supporting means, movably mounted on said frame, for supporting the lateral edges of said sheet and for incrementally longitudinally forwardly indexing said continuous sheet in successive increments relative to said frame and said billowing means from said heating means to said mold means, in said retract position, in a forward, longitudinal path of travel; and means for admitting pressurized fluid to said billowing means and upwardly directing said pressurized fluid between said sheet supporting means to upwardly billow the midportion of the sheet above said billowing means as said sheet moves past said billowing means to a level spaced from the level of said mold means in said retract position. - View Dependent Claims (11)
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Specification