Abstract: Apparatus for bending a thin flexible and narrow strip having a flat longitudinally extending base portion and a central longitudinally extending rib, comprising a cylinder mounted on a supporting base and having a helical recess extending from the bottom to the top thereof. The recess extends inwardly into the cylinder a distance slightly less than one-half of the width of the base portion of the strip. A rotatable arm is mounted on a shaft which extends upwardly and concentrically from the top of the cylinder. The arm has mounted thereon a slide member adapted to be moved towards and away from the cylinder. A rotatable wheel is rotatably mounted in the slide member, the wheel having an annular recess therein extending inwardly into the wheel a distance slightly less than one-half of the width of the base portion of the strip, the recess of the wheel being opposite to or in alignment with the recess on the cylinder.

Abstract: Apparatus for bending a thin flexible and narrow strip having a flat longitudinally extending base portion and a central longitudinally extending rib projecting upwardly from the base portion at right angles thereto, the upper edge of the rib being sharpened, the strip being of the type adapted to be attached to a printing cylinder and used for perforating or shearing paper sheets being printed, the apparatus being adapted to bend the strip at right angles to the base portion thereof to form a predetermined geometric shape, such as a rectangular shape for cutting rectangular windows in the paper sheets. The apparatus comprises a stationary die mounted on a supporting base. The stationary die is provided with a recess at the lower portion thereof extending around the entire periphery and inwardly into the stationary die a distance slightly less than one-half of the width of the base portion of the strip.