US Patent 7717795 Low vibration noise flexible shaft

A flexible shaft having ends of square cross-section for coupling a mating female driving member such as a square recess in a motor assembly, with a mating female driven member such as a square recess in a gearbox assembly, for positioning a seat in a motor vehicle. To decrease vibration and noise due to friction and relative movement between the shaft ends and the mating recesses, the sides of the shaft end portions are covered with a deformable polytetrafluoroethylene sheath applied by positioning a length of heat shrinkable tubing over each end portion and heating the tubing to shrink it onto the corresponding end portion so that it assumes the square cross-sectional shape of the end portion.