Press for curving metal sheet in two planes - has shell bent over spherical former by punch in gradual steps

摘要

The shell halves are made in a press by bending a strip of sheet metal in small steps between a punch and die. The thickness of the strip material is not altered during the bending process. The centreline of the blank form which the shell is to be made has the same shape as that of the final shell. The matrix over which the shell is formed by the die has the shape of the inner contour of the shell and has rotary symmetry so that the matrix will fit in the shell over a curved section of the shell.