Patent attributes
The linear actuator comprises an elongated first band wound in helical form about a central axis and capable of taking a retracted position and an extended position with its turns spaced from one another in the direction of the central axis, and first fasteners carried by the first band and longitudinally disposed therealong. The linear actuator also comprises an elongated second substantially flat band wound on itself, with its turns substantially transversely parallel to the central axis, and capable of taking a retracted, spiral position with its turns nested within one another and an extended position with its turns forming a helix around the central axis and generally equally radially spaced therefrom to form a telescopic column, the first and second bands, when in retracted position, in respective locations so as to clear each other. Second fasteners are carried by the second band and longitudinally disposed therealong, the second fasteners capable of cooperating with the first fasteners to releasably interlock the first and second bands. A spacer successively spaces the turns of the first band. A powered drive causes relative rotation on one hand of the first and second bands and on the other hand of the spacer about the central axis. Guide means guide the turns of the second band towards the turns of the first band to releasably interlock the first and second fasteners. A retaining member retains the first and second fasteners in interlocked fashion in the telescopic column.
