Patent ID: 8601854
Filing Date: 2013-12-10
Classification: B21D,Y10T

Abstract:
1. A method of determining the starting dimensions of a sheet metal work piece prior to bending into a sheet metal construction using a test work piece formed with an obtuse interior angle, comprising the steps of: providing said test work piece, said test work piece being formed of a same material and having plus or minus 25% of a same thickness, T, as said sheet metal work piece; measuring and recording a length, L and said thickness, T, of said test work piece; bending said test work piece into an angled form, said angled form having an interior angle, Ø; identifying first and second legs of said angled form; measuring and recording a length for said first leg, H measuring and recording a length of a first line, H determining and recording said interior angle, Ø; calculating, a first inside flange length, a=(H calculating a second inside flange length, b=(H calculating a first outside flange length, A=(H calculating a second outside flange length, B=(H calculating a Bend Deduction, BD=A+B−L; calculating an inside radius, r, comprising the steps of: calculating a distance of a neutral line from an inside surface of said test work piece, t=((2*tan((90−Ø)/2)*(T+r)−BD)/((π/180)*(180−Ø)))−r; calculating a Bend Deduction for an actual work piece having a finished interior angle, Ø calculating a starting length, L applying said starting length, L