Abstract: An improved method of warm folding polymeric sheet material and apparatus for accomplishing the method. The method involves applying conductive heat to both sides of the material prior to folding and is accomplished in steps including: (a) positioning the sheet material; (b) positioning a mandrel plate so as to define a fold line for the sheet material; (c) positioning an exterior heater against the material along the fold line; (d) positioning an interior heater element against the material opposite the exterior heater; (e) and (f) applying preselected amounts of heat to the fold line area through the heaters; (g) retracting the interior heater; (h) mechanically folding the sheet material along a fold line; and (i) annealing the fold by applying additional heat through the exterior heater. The process may also be augmented by adding additional steps.The primary use of the invention is in folding polyvinyl chloride jackets for use in enclosing floppy disks.

Abstract: Presented is a method and apparatus for the substantial automatic folding of flat pre-cut blanks of sheet material to form storage envelopes for floppy or rigid disc storage devices. The machine includes a pedestal formed in part by an electromagnet associated with a clamp plate that constitutes an Armature to retain the sheet material immovable during the folding operation. Additionally, there are provided three rams each associated with a pivotal shoe for folding selected portions of the flat sheet, and reciprocable glue dispensing means are provided for dispensing glue at the appropriate time, in an appropriate amount, and in an appropriate location. The mechanical aspects of the apparatus are connected to and controlled by a computer that scans the functions of the machine to determine if the machine is operating properly and signals the operator through an alphanumeric display panel if there is a malfunction in the apparatus.