Southwire Co. v. Cerro Wire LLC

by
Southwire’s patent is directed to a method of manufacturing an electric cable, wherein a lubricant is incorporated into the outer sheath such that the lubricant migrates to the surface of the sheath and results in a reduction in pulling force required to install the cable. One prior art solution for reducing the pulling force on a cable during installation was a post-manufacturing method of coating the cable's exterior surface with a lubricant, such as petroleum jelly, immediately before installation. Southwire explains that this was expensive and inefficient; its patent purports to improve upon such methods by incorporating a lubricant into the cable sheath material during manufacture so that the finished cable sheath comprises a lubricant that will migrate to the exterior of the sheath and lubricate the surface during installation. The Federal Circuit affirmed a determination, on inter partes review, that 42 claims are unpatentable under 35 U.S.C. 103. While the Patent Board erred in relying on inherency without finding that prior art necessarily would achieve a 30% reduction in pulling force, but rather finding that it merely renders that limitation obvious, the error was harmless because the Board made the necessary underlying factual findings to support an obviousness determination. View "Southwire Co. v. Cerro Wire LLC" on Justia Law