Alltrista Corporation

Penda Corporation

Trienda Corporation

James P Hart

William L Dresen

Charles G Geurts

Wesley W Roberts

Multiple legs elevate a central ring bearing, to which a ring-shaped rotatable plastic sheet support carousel is mounted. The carousel is fitted with a ring gear which engages with a drive system to position the carousel and the thermoplastic sheets supported from it. A multi-post vertical press is positioned with two posts extending upwardly interior to the ring bearing, and two posts extending upwardly exterior to the ring bearing. The ring bearing thus extends through the press, allowing the carousel to supply and remove plastic sheets to and from the press. An upper platen and a lower platen are mounted for vertical displacement to the posts, thereby ensuring a high degree of parallelism between the molds mounted to the platens, and accurate twin-sheet thermoforming. A plurality of rollers are mounted to the outer ring, and an elevated ring track is positioned beneath the outer ring, wherein the rollers engage with the elevated track to support a portion of the loads of the outer ring and the inner ring, the elevated track being positioned between the vertical press exterior posts and the vertical press interior post.

Track-supported rotatable sheet support structure for twin-sheet

Multiple legs elevate a central ring bearing, to which a ring-shaped rotatable plastic sheet support carousel is mounted. The carousel is fitted with a ring gear which engages with a drive system to position the carousel and the thermoplastic sheets supported from it. A multi-post vertical press is positioned with two posts extending upwardly interior to the ring bearing, and two posts extending upwardly exterior to the ring bearing. The ring bearing thus extends through the press, allowing the carousel to supply and remove plastic sheets to and from the press. An upper platen and a lower platen are mounted for vertical displacement to the posts, thereby ensuring a high degree of parallelism between the molds mounted to the platens, and accurate twin-sheet thermoforming.

Rotatable sheet support structure for a twin-sheet thermoformer

An upper thermoforming mold is positioned above a lower thermoforming mold on a platen. The platen is provided with an array of position-controlled hydraulic cylinders. A controller drives the array of cylinders to uniformly advance the two molds together once heated sheets of thermoplastic material have been formed thereon. By controlling the position of each actuator, forces may be applied at different levels to the platen to bring about uniform molded parts and reduced deflection of the molds.

Twin-sheet thermoforming apparatus with hydraulic array mold support

A four-station rotary thermoformer has a rotary carriage which transports a sheet of thermoplastic material clamped on a subframe through a load/unload station; a heating station; a forming station where the sheet is molded; and a cooling station removed from the mold where the part is cooled on the subframe. The molded sheet is cooled in a cavity which has a lower portion mounted on a lift which travels vertically to engage against an upper portion and enclose the sheet for cooling. A multiplicity of air vents discharge cooling air into the cavity. Cooling air leaves the cavity through recirculation duct. The supply of air within the cooling cavity results in a uniform current of air against the article's surface, thus providing uniform cooling. A programmable controller controls the supply of cooling air and receives input from an infrared sensor which detects the temperature of the thermoformed article and also receives information from a sensor of the cooling air temperature. The programmable controller is programmed to provide a cooling cycle consisting of a three-parts. In the first part, the air is recirculated using the heat capacity of the recirculating air in the air supply system to start cooling at a low rate. During the second part, the flow of cooling air temperature is lowered until a pre-determined maximum cooling rate is reached and held for a selected time. During the third part, the cooling air is again recirculated.

Growing community of inventors

Portage, WI, United States of America

James P Hart