Method and apparatus for roll-forming an end plate

Abstract

Upon roll-forming an end plate of hemispherical and other cup-like or dish-like configurations, a raw material disc is placed between outer die means consisting of a top outer forming die that can be vertically moved by a drive source and can be freely rotated and at least a pair of left and right outer forming rolls adapted to move along predetermined moving paths and inner die means consisting of a top inner forming die held at a predetermined position that can be driven in rotation by a drive source, and a middle inner forming roll a bottom inner roll both of which are freely rotatable, the outer die means is depressed against the inner die means, and said pair of outer forming rolls are moved along said moving paths so as to press said raw material disc against the middle inner forming roll and the bottom inner forming roll, respectively, one of said outer forming rolls being moved within an effective forming range of the middle inner forming roll, while the other being moved within an effective forming range of the bottom inner forming roll. The effective forming ranges of the middle and bottom inner forming rolls, respectively, are partly overlapped with each other. In an apparatus for effecting the above-described roll-forming operation, an effective forming angle of the bottom inner forming roll is chosen larger than an effective forming angle of the middle inner forming roll.