Patent ID: 7857309
Filing Date: 2010-12-28
Classification: B65H

Abstract:
1. A shaft driving apparatus comprising: a shaft including a first end, a second end, and one or more shaft support bearings for supporting rotational movement of the shaft; a motor, the motor operatively connected to the first end of the shaft and the motor including two or more motor bearings for supporting rotational movement of the shaft; a controller operatively connected to the motor; and a slip joint, the slip joint including a first portion and a second portion, the slip joint first portion operatively connected to the second end of the shaft, and the slip joint second portion configured to slip at a threshold rotational angle of shaft rotation; wherein the controller is configured to operate in a nonslip mode of operation to rotate the shaft, the one or more shaft support bearings, the first and second portions of the slip joint, and the two or more motor bearings a first predetermined rotational angle less than or equal to the threshold rotational angle, and the controller is configured to operate in a slip mode of operation to rotate the shaft, the one or more shaft support bearings, the first portion of the slip joint, and the two or more motor bearings a second predetermined rotational angle greater than the threshold rotational angle, and the controller is configured to subsequently return to the nonslip mode of operation, the slip mode of operation advancing a rotational angle associated with the two or more motor bearings and one or more shaft support bearings for subsequent operation in the nonslip mode.