Process of forming bend-controlling structures in a sheet of material, the resulting sheet and die sets therefor

Abstract

A process of forming bend-controlling structures, such as slits, grooves or displacements (), in a sheet of material (). The bend-controlling structures () have central portions () extending substantially parallel to a desired bend line () on the sheet and end portions () which diverge away from the bend line (). In one embodiment the process includes the step of forming the bending straps () between pairs of slit end portions () at a desired spaced apart distances along the bend line () with the straps () having a desired configuration, and the step of forming central portions () which connect the end portions () to complete the slits () using a separate die set. A plurality of end portion dies () can be used to produce end portions () of various shapes and straps () of various widths, and a single set of central portion forming dies () are used to connect the end portions (). In other embodiments die sets producing a single end portion () or mirror image impressions (A,B) are used and preferably overlapped to produce the complete bend-controlling structure (). A modular die assembly () also is disclosed in which the bend-controlling structures can be produced by modular die inserts (--). Finally, a selection of die sets () of differing length from a group of die sets can be made to position the bending straps () at desired locations along the bend line.