Driving mechanism for vacuum forming drum
AssigneeHercules Incorporated
InventorDavid James Torrans
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Abstract
The invention is a drive mechanism for a rotary vacuum forming multifaced drum to essentially match the surface speed of said drum to the constant speed of a web of film issuing from a film die. The instant invention provides apparatus to continuously vary the rotational speed of a multifaced vacuum forming drum with any number of faces, such that if a web of hot film were extruded at a constant rate, the rotational speed of the drum would vary as required to accept the film at a constant rate to provide an essentially uniform thickness of material on the surface of the drum for thermoforming.
Claims3
A driving mechanism for a forming drum comprising:
- a rotational forming drum;
- a film dye for extruding film onto the surface of said forming drum, said film being extruded from said die at a first point, and contacting the surface of the forming drum at a second point;
- a drive pulley and belt means driven by said drive pulley, said belt means contacting the periphery of said forming drum and said drive pulley, said drive pulley contacting the belt means returning from the surface of said forming drum at a third point, said first, second and third points being substantially in line and the distance from said first point to said second point being approximately the same distance from said second point to said third point.
Dependencies are inferred from the claim text.