Device for the destruction of microfilm and similar data carriers

In a shredding device adapted for the destruction of microfilm and related information carriers with microimage impressions, a shredding unit comprising in combination:

• a stationary frame;
• a shredding cutter which is rotatably supported on the frame and connected to a cutter drive, the cutter having the general configuration of a cylindrical milling cutter, with an even number of angularly spaced longitudinal cutting edges arranged on the cutter periphery;
• and
• a stationary cutting member supported on the frame and forming a stationary cutting edge which is so positioned that it cooperates with the moving cutting edges of the rotating shredding cutter to produce a shearing action therewith;
• and wherein
• the stationary cutting edge defines a stationary cutting profile of zigzag outline, similar to the profile outline of a regular screw thread, with triangular teeth and V-shaped grooves;
• the moving cutting edges of the shredding cutter define first-position and second-position moving cutting profiles alternating with one another along the cutter circumference, both moving cutting profiles having triangular teeth spaced at twice the longitudinal pitch of the cooperating V-shaped grooves of the stationary cutting edge, so as to produce a shearing action with every other of said grooves;
• and
• the first position moving cutting edges are longitudinally offset from the second-position moving cutting edges by the amount of said pitch;
• with the result that at every pass of a moving cutting edge at the stationary cutting edge against an advancing sheet of information carrier, a plurality of short, V-shaped slivers are sheared from the latter.