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 ( 22 ), in a sheet of material ( 21, 121, 221, 321, 421, 521, 621, 721 ). The bend-controlling structures ( 22 ) have central portions ( 26 ) extending substantially parallel to a desired bend line ( 23 ) on the sheet and end portions ( 27 ) which diverge away from the bend line ( 23 ). In one embodiment the process includes the step of forming the bending straps ( 24 ) between pairs of slit end portions ( 27 ) at a desired spaced apart distances along the bend line ( 23 ) with the straps ( 24 ) having a desired configuration, and the step of forming central portions ( 26 ) which connect the end portions ( 27 ) to complete the slits ( 22 ) using a separate die set. A plurality of end portion dies ( 51/54 ) can be used to produce end portions ( 27 ) of various shapes and straps ( 24 ) of various widths, and a single set of central portion forming dies ( 71/74 ) are used to connect the end portions ( 27 ). In other embodiments die sets producing a single end portion ( 27 ) or mirror image impressions (A, B) are used and preferably overlapped to produce the complete bend-controlling structure ( 22 ). A modular die assembly ( 500 ) also is disclosed in which the bend-controlling structures can be produced by modular die inserts ( 511 - 514, 611 - 614 ). Finally, a selection of die sets ( 722 a, 722 b, 722 c ) of differing length from a group of die sets can be made to position the bending straps ( 24 ) at desired locations along the bend line.

1 - 37 . (canceled)  
   
   
       38 . A method of making a three-dimensional object from a single sheet of material comprising the steps of: 
 forming a plurality of bend-controlling structures in a sheet of material, each structure having a central portion extending substantially parallel to a desired bend line and having end portions diverging away from opposite ends of the central portion;    forming an additional pre-selected number of bend-controlling structures along additional pre-determined bend lines in said sheet of material; and    bending said sheet of material along said bend lines to form the desired three-dimensional object.    
   
   
       39 . The method of  claim 38  wherein said three-dimensional objection is a load-bearing object.  
   
   
       40 . A process for positioning bend-controlling structures in a sheet of material to be bent along at least one bend line comprising the steps of: 
 positioning the bend-controlling structures extending to proximate an edge of the bend with one of:    a central portion of a bend-controlling structure parallel to the bend line extending to the edge by a distance from an end portion of the bend-controlling structure sufficiently spaced from the edge to prevent localized bending of the sheet of material at the edge in a direction transverse to the bend line, and an end portion of the bend-controlling structure defining a bending strap with the edge configured to approximate the configuration of bending straps between longitudinally adjacent bend-controlling structures; and    selecting the length and number of the bend-controlling structures along the bend line inwardly of the edge to produce a desired number of bending straps positioned along the bend line inwardly of the edge to produce a bend of desired strength.    
   
   
       41 . The process as defined in  claim 40 , and the step of: 
 positioning the bending straps along the bend line inwardly of the edge in a position directing bending stresses in the bending straps away from local weakened structural features in the sheet of material.    
   
   
       42 . The process as defined in  claim 40 , and the step of: 
 positioning more bending straps proximate the edge than the number of bending straps per unit length along a remainder of the bend line.    
   
   
       43 . The process as defined in  claim 42  wherein, 
 the positioning step is accomplished by shortening the length of the bend-controlling structures proximate the edge.    
   
   
       44 . The process as defined in  claim 40  wherein, 
 the bend-controlling structures proximate the edge define bending straps of increased transverse width dimension.    
   
   
       45 . The process as defined in  claim 40  wherein, 
 the bend-controlling structures have end portions formed to diverge from the bend line to define bending straps with obliquely oriented center lines extending across the bend line.    
   
   
       46 . The process as defined in  claim 45  wherein, 
 the edge extends at an oblique angle to the bend line, and the positioning step is accomplished by positioning the bend-controlling structure with a diverging end portion diverging in the same direction as the oblique edge.    
   
   
       47 . The process as defined in  claim 45  wherein, 
 positioning step is accomplished by positioning the central portion to extend to the edge with the end portion diverging in a direction toward an unweakened area of the sheet of material.    
   
   
       48 . A sheet of material formed for precision bending along at least one bend line comprising: 
 a sheet of material having a plurality of bend-controlling structures formed therein along alternating sides of a bend line extending to one edge of the sheet of material, the bend controlling structures including a central portion oriented substantially parallel to the bend line and at least one end portion connected to the central portion and diverging away from the bend line, and the longitudinally adjacent end portions of the bend-controlling structures defining bending straps therebetween having central longitudinal axes extending obliquely across the bend line, and the bend-controlling structure closest to the edge having the central portion thereof extending to the edge with the end portion being sufficiently spaced from the edge to prevent localized deformation of the edge upon bending of the sheet.    
   
   
       49 . The sheet of material as defined in  claim 48  wherein, 
 the sheet of material is formed with a weakened structural feature proximate the bend line, and the bend-controlling structures are positioned along the bend line proximate the structural feature in a manner preventing crack propagation to and stress concentration at the structural feature.    
   
   
       50 . The sheet of material as defined in  claim 48  wherein, 
 the bend-controlling structures proximate the edge define bending straps having increased cross sectional area per unit of length along the bend line as compared to the cross sectional area of the bending straps per unit length over the remainder of the bend line.    
   
   
       51 . The sheet of material as defined in  claim 50  wherein, 
 the number of bending straps per unit length of bend line is greater proximate the edge than remote of the edge.    
   
   
       52 . The sheet of material as defined in  claim 50  wherein, 
 the width of the bending straps proximate the edge is greater than the width of the bending straps remote of the edge.    
   
   
       53 . A modular die for forming bend-controlling structures about a bend line on a sheet of material comprising: 
 a die body having a track formed therein for receipt and mounting of a plurality of modular die members to the die body; and    a plurality of modular die members mounted in the track and including at least one modular end portion die member suitable for forming an end portion of a bend-controlling structure which diverges away from the bend line, and at least one separate modular central portion die member suitable for forming at least a segment of a central portion of the bend-controlling structure extending substantially parallel to the bend line, the modular end portion die member and the modular central portion die member being positioned in abutting relation in the track and being cooperatively formed to enable the modular die to be used to produce a continuous bend-controlling structure in a sheet of material.    
   
   
       54 . The modular die as defined in  claim 53  wherein, 
 the track extends over substantially the length of the bend line, and the modular die members are removably mounted in the track.    
   
   
       55 . The modular die as defined in  claim 53  wherein, 
 there are a plurality of modular end portion die members and at least one modular central portion die member mounted in the track.    
   
   
       56 . The modular die as defined in  claim 53  wherein, 
 the modular die members are male modular die members, and a second die body with a second track having a second plurality of modular die members formed therein, the second modular die member being female modular die members having a shape formed to cooperate with the male modular die members to produce the bend-controlling structures.    
   
   
       57 . A process of forming bend-controlling structures in a sheet of material, the structure being positioned along a desired bend line on alternating sides of the bend line and in longitudinally displaced relation to define bending straps between longitudinally adjacent bend-controlling structures, the process comprising the steps of: 
 providing a group of punching die sets with each die set in the group being formed to produce a complete bend-controlling structure of differing lengths for a single punch stroke;    selecting a combination of die sets from the group in order to enable a desired positioning and configuration of the bending straps along the bend line; and    using the selected combination of die sets to punch bend-controlling structures into the sheet of material at the desired positions.    
   
   
       58 . The process as defined in  claim 57  wherein, the providing step is accomplished by providing a plurality of die sets which have length dimensions which differ from the die set having the shortest length by a whole number multiple of the shortest length.  
   
   
       59 . The process as defined in  claim 57  wherein, 
 the providing step includes the step of providing at least a second group of die sets having differing lengths and bend-controlling structure end portions which differ in shape from the bend-controlling structure end portions of the die sets in the first-named group; and wherein,    the selecting step is accomplished by selecting from both the first-named group and the second group.