Patent ID: 8006821
Filing Date: 2011-08-30
Classification: G07F

Abstract:
1. A rotary anti-pullback unit of fletched fins comprising: a rotor and a frame for rotatably supporting the rotor, wherein the rotor comprises a plurality of disks arranged coaxially in a line and in axially spaced relation to each other, and a plurality of fletched fins axially protruding from radial surfaces of the disks toward an opposite radial surface of the other adjoining spaced disk, each of the fins comprises a radially outwardly tapered guide surface formed at the radially outer edge of the fin, a barb formed at the radially inner edge of the fin and a hook formed in each tip of the fins between the guide surface and barb for each fin to axially protrude toward to an opposed radial surface of the spaced adjoining disk so that the hook is closer to the opposed radial surface of the adjoining disk than that fin axially protruding from the opposed radial surface of the spaced adjoining disk.