Obviousness Found Even When the Burden to Prove Inherency Remains on Examiner

Yoshiya Nakamura | October 18, 2017


September 8, 2017

Before Lourie, Moore and Hughes.  Opinion by Lourie.


Southwire Co. (the patent owner) owns No. 7,557,301 (the ’301 patent). An inter parte reexamination is initiated by a third party requestor, Cerro wire LLC (the requester).  All the claims of the ’301 patent are found obvious over prior art references under 35 U.S.C. § 103.  It is decided in the reexamination that one of the combinations of cited references inherently discloses a claimed parameter at issue.  CAFC affirms PTAB’s conclusion that the claims are unpatentable as obvious, while rejecting part of the reasoning that the claimed parameter is inherently disclosed in the cited references.

Japanese Summary





The ’301 patent discloses a method of manufacturing an electric cable, incorporating lubricant into an outer sheath during the manufacturing process 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 is applying a lubricant to the cable when installed.

Representative claim 1 of the ’301 patent recites:

 1.  In a method of manufacturing a finished electrical cable having a conductor core and a jacket formed primarily of a first material, the jacket surrounding at least said conductor core and defining the outermost exterior surface of the finished cable, the improvement comprising

combining a preselected lubricant with said first material prior to the formation of said jacket to provide a reduced coefficient of friction of said outermost exterior surface and also reduce the amount of force required to pull the cable during its installation,

in which migrates through said jacket to be available at said outermost exterior surface of said finished cable during the cable’s installation through building passageways, the finished electrical cable having the characteristic that an amount of force required to install said cable through corresponding holes in an arrangement of four 2″ x 4″ wood blocks having holes drilled at 15° through the broad face and the centerlines of the holes are offset 10″ and pulled through at 45° to the horizontal from the last block is at least about a 30% reduction in comparison to an amount of force required to install a non-lubricated cable of the same cable type and size through corresponding holes in said arrangement.

Among various combinations of prior art references are discussed in the rejections in the inter parte reexamination, the patent owner appealed to CAFC attacking one combination of “Summers” and two secondary references.  The patent owner disputes the Board’s interpretation of Summers in CAFC.  The patent owner also argued that evidence of long-left need rebuts the obviousness rejections.  PTAB agreed with most arguments from the requester, finding that “the finished electrical cable having the characteristic that an amount of force required to install said cable … is at least about a 30% reduction in comparison to an amount of force required to install a non-lubricated cable of the same cable type and size …” is an inherent result from the cable produced by the method disclosed in Summers.

The main reference, Summers, contains the following passage:

Cable jackets 45, 55 can be formed of a suitable plastic material, for example polyethylene, and, to reduce resistance to a cable pulling force, can include a friction reducing additive therein.  The friction reducing additive can function by migrating to the surface of cable jackets 45, 55 and lubricating the interface between the cable jackets and virtually any surface of or in the cable passageway. … Examples of suitable friction reducing additives include fatty acids compounds or derivatives, e.g., glycerol mono-stearate, stearic acid, or a fatty amide wax.

(Col. 3, line 65 to col. 4, lines 12.)

The patent owner argues that Summers “teaches five different factors that could go into reducing pulling force, with the coefficient of friction being only one of them” and “does not say which of these factors contributes how much to a reduction in pulling force, if at all.”  The patent owner also submitted their expert’s (Mr. Sasse) declarations showing that increased amounts of lubricant added to the material does not always result in a decreased coefficient friction.

However, PTAB picked some data from the declarations to support the obviousness conclusion.

(Reproduced from the PTAB decision, pages 12 and 15.)

The patent owner argues that PTAB engaged in improper picking and choosing “in selecting only the data from the declarations, by evidence that supported the expert’s conclusion that there is no necessary relationship between the concentration of lubricant added to a polymeric material and that material’s coefficient of friction” and omitting critical data that “runs directly counter to the Board’s conclusion.”

Although Summers never measures a pulling force or friction of the cable, the PTAB finds that Summers implicitly compares cable pulling force for cable jackets having a friction reducing additive to cable pulling force for cable jackets of similar dimension.  PTAB held that the 30% reduction limitation is inherently present in Summers because this reference “teaches that the lubricant must reduce the friction and lubricate the cable passageway, reasonably suggesting the pulling must also be reduced.

As to the patent owner’s argument based on a long-felt need, PTAB held that, “while Southwire [the patent owner]’s evidence showed a long-felt need, it did not establish a long-felt need without solution,” because Summers suggested similar solutions using a lubricant in the manufacturing process.

CAFC first discusses the issue of inherency and rejected the requester’s argument that a prima facie case for obviousness is met where the only difference between the claimed and prior art process is a property that results from performing the process, by holding, as decided in many precedent cases:

the Board erred in relying on inherency in making its obviousness determination.  We have held that “the use of inherency in the context of obviousness must be carefully circumscribed because ‘[t]hat which may be inherent is not necessarily known’ and that which is unknown cannot be obvious.” … we have emphasized that “the limitation at issue necessarily must be present” in order to be inherently disclosed by the reference.

CAFC stated that PTAB erred in concluding that Summers renders it obvious to have selected lubricant amounts that can achieve that same result, without finding that Summers necessarily would achieve a 30% reduction in pulling force.

However, CAFC agrees the conclusion in PTAB that the claims at issues are obvious over the cited references.  Based on the findings that Summers discloses an “identical or substantially identical” process, and the patent method does not differ “in any material way from the process disclosed in Summers (in view of Dow),” CAFC indicates that the burden to “prove that the subject matter shown to be in the prior art does not possess the characteristic relied on” is shifted from the PTO to the applicant.  In this case, CAFC affirms the obviousness conclusion because the patent owner did not provide any evidence or any explanation in the specification that the claimed characteristic is an unexpected result or “something other than an observed result of an old process.”

As to the long-left need argument, CAFC agrees with the conclusion in PTAB, holding that objective evidence submitted by the patent owner is insufficient because it “lacked a nexus to the claimed invention, and that any long-felt need adduced from the evidence had already been met by Summers because the prior art “indisputably provided several solutions before the ’301 patent’s priority date.

Take Away

The burden to prove inherency remains on examiner in the absence of evidence of record establishing that a method disclosed in prior art necessarily satisfies the claimed limitation.  Even so, obviousness can be found if the applicant fails to prove that the claimed limitation is unexpected or something other than an observed result of the disclosed process when the process appears identical to the claimed process.

Full Opinion

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