1. Field of the Invention
The present invention is directed to a device for stripping blanks from a die cut sheet of blanks, which device includes an upper movable set of punches and a lower stationary matrix.
2. Prior Art
Stripping tools or devices designed to separate various blanks from a previously die-cut sheet of blanks from each other generally consist of an upper movable punch and a lower fixed matrix. The sheet of blanks are usually formed by a press, for example by a platen press with the blanks being interconnected together by nicks and also connected by nicks to a peripheral waste area. When the blanks are stripped from the sheet, the upper movable punch pushes each of the blanks through openings in the lower matrix, which causes a rupture of the various interconnecting nicks that extend between the blanks and between the blanks and the outer peripheral waste area.
In previously known devices, the punches have been made to conform to the outline of the blank to be stripped and the punches can be made of synthetic resin or wood. Since the sheet of blank, which is to be stripped, has considerable dimensions, it is conspicuous that several punches may be required to be used simultaneously. The punches are aligned with the die cutting tool of the press and secured on a base plate or punch frame which itself is held within an upper tool carrier frame of the stripping station of the press. Opposite each punch, a lower matrix, which has a size of the sheet and has a plurality of openings, which conform to the outline of the blanks, which are to be stripped from the sheet, is mounted. The matrix consists of small bars of reinforced synthetic material, which are arranged in a way that they cross one another to form a grid, which has a mesh with openings of about the same dimension as the blanks that are to be stripped from the sheet.
Since the stripping tool or device of this type can be used only for a given blank size, it involves a relatively high cost. Each time another job is to be undertaken, for example, with a change of the size or shape of the blanks, a new punch and also a new matrix must be prepared and installed in the press.
USPTO Backgrounds
USPTO Backgrounds