Side flap fold apparatus for a disk envelope

Apparatus for forming side flap folds in an envelope for a flexible disk from a flexible plastic prepunched blank having two connected sections one of which has side flaps extending from opposite side edges thereof comprising:

• a frame;
• a plate held by said frame and having an outwardly facing surface;
• a mandrel having the flexible plastic blank folded about an end thereof so that said side flaps of the blank extend beyond the side edges of said mandrel;
• said mandrel holding the plastic blank half having the flaps extending therefrom against the bottom surface of said plate;
• a raised edge portion pxtending along the side edges of said mandrel on the outward facing surface thereof and having a predetermined height, width and a curved surface thereon;
• a pair of folding blades each folding a flap around the adjacent side edge of said mandrel;
• a pair of means located within said frame to guide said associated folding blade in an arcuate path to fold said associated flap around the adjacent edge of said mandrel;
• drive means for rotating said folding blades about said pivot means in opposite directions;
• stop means for stopping said folding blades arcuate path movement;
• upward motion means associated with each of said pivot means and operable subsequent to said pivot means and said stop means operation in response to said drive means to cause compression of said flaps by said folding blades beyond said raised edge portions providing an overfold zone adjacent said raised edge portions;
• radiant heating means operable to anneal each of said folds relieving any stresses therein;
• and
• guiding means for directing said radiant heat to said folds and shielding non-folded areas from the heat.