Patent ID: 7789824

Claim:
An instrument comprising a cable or tube, and at least one propulsion device for moving the cable or tube in a hollow space, wherein the propulsion device comprises a shape of a donut, said donut-shaped propulsion device comprising a ring that has a straight axis through its open center, wherein said ring lies in a plane perpendicular to the straight axis, wherein said cable or tube extends centrally along the straight axis into the immediate vicinity of said donut-shaped propulsion device such that the donut-shaped propulsion device lies in a plane at right angles to the longitudinal direction of the cable or tube, and wherein the donut-shaped propulsion device is, at least in part, externally delimited by at least one wire gauze that is rotatable about a closed axis of the donut-shaped propulsion device, wherein said closed axis lies in the plane of the donut, wherein the wire gauze externally delimiting the at least one donut-shaped propulsion device is fastened to the cable or tube by adjustable arms, wherein the cable or tube is provided with a sleeve, to which sleeve first ends of the arms are hingingly fastened, and in that opposite to the first ends, second ends of the arms are coupled with the at least one wire gauze, wherein the at least one wire gauze is coupled with a drive that is located at a proximal end of the cable or tube.