Patent ID: 8371149

Claim:
A method comprising: forming a sheet metal blank comprising: a first bending member that forms a first blank edge; a second bending member that forms a second blank edge; and a wedge-shaped recess that is formed by a first straight segment of the blank, a second segment of the blank, and a rounded segment of the blank that interconnects the first and second straight segments, in the sheet metal blank, a first point is located at an intersection of lines along which the first and second straight segments extend, the first point being positioned at a distance u from a first bending line of the first bending member and at a distance x from a second bending line of the second bending member, the first straight segment extending along a line that passes through the first point and a second point, the second point being positioned at a distance v from the first bending line of the first bending member and at a distance z from the second bending line of the second bending member, the first straight segment terminating at the first blank edge of the first bending member, the second straight segment extending along a line that passes through the first point and a third point, the third point being positioned at a distance T from the first bending line of the first bending member and at a distance y from the second bending line of the second bending member, the second straight segment terminating at the second blank edge of the second bending member, in the sheet metal blank, the distances T, u, v, x, y, z are selected in accordance with the first inner bending radius R i,1 , the second inner bending radius R i,2 , the thickness S of sheet metal blank, and a shortening factor VK by which the sheet metal blank is extended during bending, as: T =(0.7 *S+VK/ 2)±20%, u =(1.0 *R i,1 )±20%, v =(1.0 *R i,1 )±20%, x =(1.0 *R i,2 )±20%, y =(0.25 *R i,2 )±20%, and z =( VK/ 2−0.1)±20%; and forming said sheet metal blank into a shape by bending said first and second bending member.