Machine for making expanded metal

Abstract

Apparatus for manufacturing expanded sheet stock is disclosed. The apparatus includes a stationary knife having a cutting edge defining one edge of a strip feed slot. While the strip is fed through the slot, a movable knife passes across the slot to form half-diamond-shaped openings in the strip with each stroke. The movable knife has a cutting edge which is defined by a plurality of adjacent obelisk teeth and those teeth form the half-diamond openings during each stroke. The movable cutting knife is driven relative to the stationary knife in planar alignment therewith and in simple harmonic motion while the strip is fed through the slot so that any point on the cutting edge of an obelisk tooth sequentially shears the strip in a recurring sequence to provide half-tooth spacing between successive cuts. Such spacing results in a characteristic diamond-shaped opening in the expanded metal. According to a preferred aspect of this invention, four feed slots are provided and two movable knives have parallel cutting edges which respectively serve adjacent feed slots. The knives are driven in opposite directions to minimize machine vibration, and the knife driving mechanisms are also driven in opposite directions. According to a further aspect of this invention, the strip feed mechanism operates continuously and the strip is intermittently stopped by the shearing action of the movable knife. According to another aspect of this invention, a clamp holds the strip against the stationary cutting knife during the shearing operation.