Patent ID: 7168355
Filing Date: 2007-01-30
Classification: D01G,Y10S,Y10T

Abstract:
1. A chopper for separating long lengths of unwound item(s) selected from the group consisting of fibers, fiber strands, string, yarn, wire, tape and ribbon into short pieces, the item(s) running speed of above about 3000 ft/min, comprising a frame, a rotatable backup roll outboard of one side of the frame, the backup roll having a peripheral working layer, a rotatable blade roll outboard of the side of the frame, the blade roll having a plurality of blades spaced apart around its periphery for contact with and penetration of said items and into the peripheral working layer and a biasing system for biasing the blades of the blade roll and the backup roll together, the improvement comprising: the biasing system being an assembly for biasing the blade roll and the backup roll together with an adjustable, but substantially constant force, said force being such that the blades of the blade roll will penetrate the peripheral working layer of the backup roll only a desired distance while separating the items into short pieces, the biasing system comprising a screw lack that extends and retracts as an element of the screw jack is rotated first one direction and then the opposite direction, a motor for rotating the element and a slip clutch that can maintain a substantially constant torque to the element of the mechanical jack during setup and operation of the chopper even when a thicker portion of the items passes through a nip between the blade roll and the backup roil, said slip clutch being located between said element of the screw jack and the motor.