Patent ID: 7213796

Claim:
A linear actuator comprising: 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 said central axis; first fastening means carried by said first band and longitudinally disposed therealong; an elongated second substantially flat band wound on itself, with its turns substantially transversely parallel to said 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 said central axis and generally equally radially spaced therefrom to form a telescopic column, said first and second bands, when in retracted position, in respective locations so as to clear each other; second fastening means carried by said second band and longitudinally disposed therealong, said second fastening means capable of cooperating with said first fastening means to releasably interlock said first and second bands; spacer means to successively space the turns of said first band; drive means to cause relative rotation on one hand of said first and second bands and on the other hand of said spacer means about said central axis; guide means to guide the turns of said second band towards the turns of said first band to releasably interlock said first and second fastening means; and retaining means retaining said first and second fastening means in interlocked fashion in said telescopic column.