A device for providing relative movement between three telescopically co-ordinated parts (1, 2, 3) which comprises a power device (7) of a type variable in length and acting between a point (8) on a first (1) and a point (9) on a second (2) of the parts, and a flexible traction element (12), which is...http://www.google.es/patents/US4690290?utm_source=gb-gplus-sharePatente US4690290 - Device of the kind comprising at least three movably co-ordinated parts
Device of the kind comprising at least three movably co-ordinated parts
