Patent ID: 6012621
Filing Date: 2000-01-11
Classification: G02B,H02G

Abstract:
An apparatus for conveying a cable, such as through a conduit, the cable having a longitudinal axis extending in the longitudinal direction of the cable, the apparatus comprising:a drive assembly including a moveable drive member for frictionally engaging an outside surface of the cable and for applying a friction force so as to move the cable in the longitudinal direction;a drive assembly sensor and signal generator for sensing movement of the moveable drive member of the drive assembly, and for generating a signal indicative of the sensed movement of the drive member;a cable sensor and signal generator for sensing movement of the cable, and for generating a signal indicative of the sensed movement of the cable; anda control system which controls movement of the movable drive member of the friction drive assembly, the control system including circuitry for receiving the signal from the drive assembly sensor and signal generator and the signal from the cable sensor and signal generator, the control system including further circuitry for comparing the signals so as to compare movement of the drive assembly and the cable over time wherein a drive assembly shut off signal is generated by the control system if a predetermined speed difference exists between the drive assembly and the cable.