Importance

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Abstract

Disclosed is an apparatus for thermoforming a thermoplastic blank (10) into a plastic container (1) having a cup-shaped main body (2) with a radially extending flange (3). A blank holder (12) is conveyed by a conveyor (15) along a predetermined path of travel in a predetermined direction. During one circulation, a plurality of blanks are supplied by a blank feeder (16) to the blank holder, a central portion (10a) of each blank is heated by direct contact with upper and lower heating boards (19a, 19b) of heating unit (18) to preferably above a melting point of the blank material, then the heated portion is formed into the cup-shaped main body by a forming unit (20), then a peripheral portion (10b) is annealed by a flange annealing unit (26), and finally the product containers are removed from the blank holder by a pick-up unit (28). The vacant blank holder (12') is returned to the blank feed station. An annular ridge (3a) or skirt flange (3b) may be formed, preferably at the flange annealing station. A half-notch may be formed from the top surface of the peripheral portion of the blank to a predetermined depth to improve peel-off property of a plastic film lid which is heat-sealed to the flange of the product container, located at a third predetermined location forward of the second predetermined location in the direction of travel of the blank holder along the path of travel thereof, for forming the heated central area of the blank into a predetermined cup shape of the main body of the container.

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First Claim