Side flap fold apparatus for a disk envelope

摘要

The flexible disk envelope is formed from a flexible plastic prepunched blank having two connected sections. One section of the blank has side flaps extending from the opposite side edges. The blank is folded about an end of a mandrel so that the side flaps extend beyond the side edges of the mandrel. The mandrel holds the plastic blank section having the flaps extending therefrom against the bottom surface of a plate. The mandrel has raised edge portions running along the side edges on the outward facing surface thereof. The side flaps are folded around the adjacent edge of the mandrel in an outward folding direction by folding blades which are driven about pivot means to guide the folding blades in an arcuate path. Stops are provided which stop the arcuate motion of the folding blades and allow the upward motion means associated with the pivot means in response to the drive means to cause compression of respective flaps against the adjacent blank section and mandrel by said folding blades beyond said raised edge portions providing overfold zones Infra-red heating means are operable through windows in the folding blades adjacent the side folds to provide annealing of the fold thereby relieving any stresses therein.