Patent ID: 7857596

Claim:
A vane or rotor blade for a wind powered generating unit, comprising: a structural element comprising a block which comprises a plurality of body segments of a foamed, thermoplastic material having a stretched polymer structure in one direction, the body segments being arranged next to each other and joined together on a plane defining foam sheets running transverse or perpendicular to the one direction of the stretched polymer structure, wherein the structural element is a plastic sheet having opposed relatively large area sides, and relatively small area edges, and where the stretched polymer structure is in a direction perpendicular to the relatively large area sides, wherein the structural element is made wholly of plastic and the body segments are welded together at abutting side faces forming weld seams, whereby the weld seams form a substantially pore-free intermediate plastic layer in the form of a network of stiffening struts defined by intersecting weld seams, wherein each of the weld seams have a thickness such that a network strut structure is formed by the weld seams which increases the compressive strength of the structural element with respect to surface pressure.