Patent ID: 7109704

Claim:
A flexible shaft having a length between a lead end and a tail end for moving a measuring device on the shaft lead end through a pipe, the improvement comprising, a flexible inner core functionally able to sustain without inner core deformation longitudinal compression forces that are derived from pushing the shaft through the pipe rollers, a data cable helically wound on and in contact with the inner core, a flexible outer sleeve outermost on the shaft with a longitudinally even outer surface running uninterrupted continuously between the shaft lead and tail ends, the outer sleeve enclosing the data cable and inner core and engaging the data cable in direct circumferential contact throughout the shaft length therein providing a radial structural connection between the outer sleeve and the inner core through the data cable such that rollers of a shaft pusher smoothly engage the even outer surface of the outer sleeve throughout the shaft length, with radial forces imparted from the rollers on the outer sleeve being conveyed to the inner core through the data cable, the outer sleeve thus sustained from collapsing by structural support provided by the inner core communicated to the outer sleeve through the data cable.