US Patent 8006821 Rotary anti-pullback unit of fletched fins

A rotary anti-pullback unit is provided which comprises a rotor 22 and a frame 43 for rotatably supporting the rotor 22. Rotor 22 comprises a plurality of disks 25 arranged coaxially in a line and in axially spaced relation to each other, and a plurality of fletched fins 26 axially protruding from at least one radial surface 25a of disks 25 toward an opposite radial surface 25a of the other adjoining spaced disk 25. Rotor 22 is rotated concurrently with a bill 70 transported along each outer periphery of disks 25 in contact to transported bill 70 to radially inwardly move a flexible extracting tool 71 connected to bill 70, and bring tool 71 into tangled engagement with fin or fins 26 in order to prevent unduly extraction of bill 70.