Patent ID: 8793965

Claim:
A semi-finished product ( 1 a ) having a tubular sleeve element ( 4 ) which extends along a longitudinal axis (A) and at least a first ( 3 a ) and at least a second ( 3 b ) strut element arranged inside the sleeve element ( 4 ) with the strut elements disposed spaced apart from one another in direction of the longitudinal axis or disposed one behind the other in direction of the longitudinal axis and may overlap one another, wherein the first strut element ( 3 a ) extends from a first point (P 1 ) to a second point (P 2 ), and the second strut element ( 3 b ) extends from a third point (P 3 ) to a fourth point (P 4 ), wherein said points (P 1 , P 2 , P 3 , P 4 ) considered in a plane perpendicular to the longitudinal axis (A) form four corner points of a rectangle, wherein the first (P 1 ) and the second (P 2 ) points form corner points of the rectangle which are opposite each other relative to the longitudinal axis (A), wherein the strut elements ( 3 a , 3 b ) are designed in such a way and arranged inside the sleeve element ( 4 ) in such a way that essentially no tensile forces can be exerted on the strut elements ( 3 a , 3 b ) by the sleeve element ( 4 ), by means of the strut elements ( 3 a , 3 b ) are not fastened to the sleeve element ( 4 ) and do not adhere to the sleeve element ( 4 ).