Bending device for metallic plate

A metal plate bending device comprising a lower die having a main body with a pair of semi-circular cross-sectional recesses formed on an upper surface thereof in a symmetric design with respect to a center line and a pair of swingable members swingably received in said recesses respectively, and an upper die arranged above said lower die movably along the center line, wherein said upper die is moved toward a metal plate mounted on said lower die to impart a press-push force to the metal plate to thereby cause the swingable members to swing and at the same time bend the metal plate along the center line,

• wherein each of said swingable member has a movable plate unfixedly and detachably mounted on a completely flat upper surface of said swingable member, and a spring means for providing a biasing force directly to said movable plate to return said movable plate to a standby condition when the press-push force by said upper die is released,
• said movable plate providing a completely flat lower surface for slidable, planar contact with the upper surface of said swingable member and providing a completely flat metal plate supporting surface, said movable plate being slidable with respect to said swingable member, and being movable together with said metal plate along with deformation of said metal plate,
• wherein a plurality of the metal bending devices are connected in series in a lengthwise direction for bending a metal plate longer than a length of a single metal plate bending device, with a selected one of said movable plates equal to or longer than the length of said long-length metal plate, which is mounted successively over said plural metal plate bending devices.