In Southwire Co. v. Cerro Wire LLC, [2016-2287] (September 8, 2017), the Federal Circuit affirmed the PTAB’s decision in an Inter Partes reexamination that the claims of U.S. Patent No. 7,557,301 on a method of making cable are unpatentable under 35 USC 103.

The invention related to the inclusion of lubricant in the plastic jacket of electrical cable that will migrate to the exterior of the sheath and lubricate the surface during installation. The Board affirmed the Examiner’s rejection of the claims over prior art that included a fiber optic cable that can include a friction reducing additive that migrates to the surface of the cable jacket. Although the prior art did not specifically teach some of the details, such as a 30% reduction in pulling force, the Board held that where the claimed and prior art products are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established, and thus the claimed details were inherent.

The Federal Circuit found that the Board erred in relying on inherency in making its obviousness determination. The use of inherency in the context of obviousness must be carefully circumscribed because that which may be inherent is not necessarily known and that which is unknown cannot be obvious. While the Federal Circuit has recognized that inherency may supply a missing claim limitation in an obviousness analysis, the limitation at issue necessarily must be present in order to be inherently disclosed by the reference. The Federal Circuit noted that the Board cited no evidence that the claimed 30% reduction in the pulling force would necessarily result from the claimed process, which contains no steps that ensure such reduction.

Thus the Federal Circuit found that the Board erred in relying on inherency without finding that Summers necessarily would achieve the claimed 30% reduction in pulling force, but rather finding that it merely renders that limitation obvious. The Federal Circuit concluded, however, that the Board’s error was harmless because it did not need to invoke inherency.

The Federal Circuit said that none of the patented steps differ in any material way from the process disclosed in the prior art, and there was no evidence that the claimed 30% reduction in pulling force would have been unexpected or unattainable. In fact, the Federal Circuit said there was no evidence that the process disclosed in the prior art did not produce at least 30% reduction. Simply because the prior art never quantified the reduction in pulling force achieved by its disclosed embodiments does not preclude the possibility, or even likelihood, that its process achieved the claimed reduction, especially since its stated purpose was the same. The Federal Circuit concluded that in the absence of any evidence that the claimed 30% reduction would have been unexpected in light of the prior art, there is no indication that the limitation is anything other than mere quantification of the results of a known process.