| abstract |
A planar blank is provided which permits the manufacture of a coil spring suitable for implantation. The blank has an elongated, essentially straight mid section which at its ends passes over into sections that are bent in the plane of the blank in opposite directions to form a blank having Z-shape. A coil spring made from the blank (in which the spring material as seen in cross section has radially flattened shape) at its ends has a lower pitch than the mid section or no pitch at all. |