US Patent 7104741 Fastening means and process for its manufacture

The present invention is directed to a fastener device that includes a base portion. At least one shank is coupled to the base portion. The at least one shank includes an end configured to be driven into a material. The at least one shank also includes a weakened shank region disposed between a first adjacent shank region and a second adjacent shank region. The weakened shank region includes a cross-section irregularly weakened with respect to the cross-sections of the first adjacent shank region and the second adjacent shank region.