United States Court of Appeals 

for the Federal Circuit ______________________ 

SOUTHWIRE COMPANY,

Appellant

v.

CERRO WIRE LLC, FKA CERRO WIRE, INC.,

Appellee

______________________ 

2016-2287

______________________ 

Appeal from the United States Patent and Trademark 

Office, Patent Trial and Appeal Board in No. 95/000,696.

______________________ 

Decided: September 8, 2017

______________________ 

 KIRK T. BRADLEY, Alston & Bird LLP, Charlotte, NC, 

argued for appellant. Also represented by KEITH E.

BROYLES, Atlanta, GA; CHRISTOPHER L. MCARDLE, New 

York, NY.

 PAUL RICHARD STEADMAN, DLA Piper US LLP, Chicago, IL, argued for appellee. Also represented by JENNIFER 

E. LACROIX. 

______________________ 

Before LOURIE, MOORE, and HUGHES, Circuit Judges.

LOURIE, Circuit Judge. 
2 SOUTHWIRE CO. v. CERRO WIRE LLC

Southwire Co. (“Southwire”) appeals from the decision 

of the U.S. Patent and Trademark Office (“the PTO”) 

Patent Trial and Appeal Board (“the Board”) in an inter 

partes reexamination concluding that claims 1–42 of U.S. 

Patent 7,557,301 (“the ’301 patent”) are unpatentable 

under 35 U.S.C. § 103. See Cerro Wire, Inc. v. Southwire 

Co., No. 2015-004351, 2015 Pat. App. LEXIS 10285

(P.T.A.B. Sept. 29, 2015) (“Final Decision”); Cerro Wire, 

Inc. v. Southwire Co., No. 2015-004351, 2016 Pat. App. 

LEXIS 1942 (P.T.A.B. May 2, 2016) (decision on request 

for rehearing). For the reasons that follow, we affirm. 

BACKGROUND

Southwire owns the ’301 patent, which 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. See, e.g., ’301 patent Abstract. According to the 

patent, one prior art solution for reducing the pulling 

force on a cable during installation was a postmanufacturing method of coating the exterior surface of 

the cable with a lubricant, such as petroleum jelly, immediately prior to installation. See id. col. 1 ll. 25–28. 

Southwire explains that this solution was referred to as 

applying “soap” to the cable, and that it was expensive 

and inefficient. See, e.g., Appellant’s Br. 5–6. The ’301 

patent purports to improve upon the prior art 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. 

See ’301 patent col. 2 ll. 40–65.

Claim 1 of the ’301 patent is illustrative and reads as 

follows:

1. In a method of manufacturing a finished electrical cable having a conductor core and a jacket 
SOUTHWIRE CO. v. CERRO WIRE LLC 3

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 in 

order to provide a reduced coefficient of friction of 

said cable outermost exterior surface and also reduce the amount of force required to pull the cable, during its installation through building 

passageways, 

in which said lubricant is of the type 

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.

’301 patent, Reexamination Certificate, col. 1 ll. 25–47

(emphases and paragraph breaks added).

On September 14, 2012, Cerro Wire, Inc. (“Cerro”) 

filed a request for inter partes reexamination of the ’301 

patent. That patent had undergone two previous ex parte
4 SOUTHWIRE CO. v. CERRO WIRE LLC

reexaminations wherein original claims 1–21 were determined to be patentable and new claims 22–29 were added. 

During the inter partes reexamination here on appeal, in 

which Southwire sought to add claims 30–42, the Examiner concluded that all claims, 1–42, would have been 

obvious over various combinations of prior art. 

Only one combination is at issue in this appeal—U.S. 

Patent 6,160,940 (“Summers”), in view of Dow Corning 

Corporation, DOW CORNING® MB50-011 Masterbatch 

(1997-99) (“Dow”) and Underwriters Laboratories, Inc., 

STANDARD FOR SAFETY NONMETALLIC-SHEATHED CABLES

32–34 (2000) (“UL-719”)—and Southwire disputes only 

the Board’s interpretation of Summers. 

Summers describes a “fiber optic cable that is suitable 

for installation in a cable passageway” and teaches that 

“to reduce resistance to a cable pulling force,” the plastic 

material used to form the cable “can include a friction 

reducing additive” that “migrat[es] to the surface of the 

cable jacket,” such as, for example, fatty acids and silicone 

oils. Joint Appendix (“J.A.”) 169–70. Although Summers

does not expressly teach that the friction reducing additive can reduce the pulling force by “at least 

about . . . 30%,” as required by claim 1, the Examiner 

adopted Cerro’s argument that the finished cable of 

Summers, in view of the other references, “has the characteristic that an amount of force required to install said 

cable . . . is at least a 30% reduction” because that characteristic “is an inherent result of the cable being made in 

accordance with the method steps.” See Final Decision, 

2015 Pat. App. LEXIS 10285, at *9–10 (internal quotation 

marks omitted).

Southwire appealed to the Board, which affirmed, 

concluding that the Examiner’s rejection was supported 

by a preponderance of the evidence. See id. at *10–11. 

The Board explained that “[w]here the claimed and prior 

art products are . . . produced by identical or substantially 
SOUTHWIRE CO. v. CERRO WIRE LLC 5

identical processes, a prima facie case of either anticipation or obviousness has been established.” Id. at *12. It

found that Summers’s lubricants “would achieve the 

claimed force reduction” because Summers (in view of 

Dow) teaches the same method steps—namely, extruding 

a cable jacket formed from a plastic material containing a 

lubricant, such that the lubricant migrates to the surface 

of the jacket and lubricates the interface between the 

cable and any surface of the cable passageway. Id. at *13. 

The Board explained that because the claims recite “a 

preselected lubricant” chosen to “provide a reduced coefficient of friction,” they “require an amount of lubricant 

which meets the stated reduction in [coefficient of friction].” Id. at *16. Thus, the Board concluded, because

Summers teaches reducing the coefficient of friction using 

a lubricant, it inherently teaches the 30% reduction 

limitation because it renders it “obvious to have selected 

[lubricant] amounts” that achieve the claimed reduction. 

Id. at *16 (internal quotation marks omitted). 

The Board rejected all of Southwire’s evidence as lacking factual support. The Board found that the three

declarations of Southwire’s expert, Mr. Sasse, were unpersuasive because the data tables provided therein fail to 

report standard deviations, statistical significance, or 

certain relevant details of the experimental design. Id. at 

*16–21. The Board found that all of Southwire’s objective 

evidence lacked factual support because it contained only 

“general allegation[s]” without corroborating evidence. 

Id. at *24–26. Furthermore, the Board found that the 

objective evidence related generally to one of Southwire’s 

products (SIMpull), with no evidence that SIMpull embodies the 30% reduction, or any other, claim limitation. Id.

at *25, *26, *30–34. The Board found that, while Southwire’s evidence showed a long-felt need, it did not establish a long-felt need without solution—rather, the solution 

had been provided by Summers because the need was for 

a (general) alternative to the prior art use of “soap” on the 
6 SOUTHWIRE CO. v. CERRO WIRE LLC

cables, not for a (specific) 30% reduction in pulling force 

using lubricants incorporated into the sheath. Id. at *33–

36.

Southwire timely appealed to this court. We have jurisdiction pursuant to 28 U.S.C. § 1295(a)(4)(A). 

DISCUSSION

We review the Board’s legal determinations de novo, 

In re Elsner, 381 F.3d 1125, 1127 (Fed. Cir. 2004), and the 

Board’s factual findings underlying those determinations 

for substantial evidence, In re Gartside, 203 F.3d 1305, 

1316 (Fed. Cir. 2000). A finding is supported by substantial evidence if a reasonable mind might accept the evidence to support the finding. Consol. Edison Co. v. 

NLRB, 305 U.S. 197, 229 (1938). Obviousness is a question of law, based on underlying factual findings, including what a reference teaches, whether a person of 

ordinary skill in the art would have been motivated to 

combine references, and any relevant objective indicia of 

nonobviousness. Apple Inc. v. Samsung Elecs. Co., 839 

F.3d 1034, 1047–48, 1051 (Fed. Cir. 2016) (en banc).

Southwire argues that, as an initial matter, the Board 

erred in relying on “inherency” in making its obviousness 

determination. Second, Southwire argues that Summers

does not inherently teach the “at least about a 30% reduction” in pulling force limitation because a limitation is not 

inherent in a reference unless it is necessarily, i.e., always, present. Thus, Southwire argues, the Board’s

finding that a “skilled artisan would have had reason to

select [lubricant] concentrations that did” achieve the 30% 

reduction in pulling force is the antithesis of inherency, 

which requires certainty, not experimentation. Final

Decision, 2015 Pat. App. LEXIS 10285, at *21. 

Cerro responds that substantial evidence supports the 

Board’s finding that any cable made with the same manufacturing steps as Summers (in view of Dow), using the 
SOUTHWIRE CO. v. CERRO WIRE LLC 7

same lubricant in amounts sufficient to reduce the coefficient of friction and pulling force (as disclosed in Summers

and Dow), would also produce the same result recited in 

the claims. Cerro contends that it is well-established law 

that, in cases such as this one, 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. Cerro argues that it is not 

inventive to claim a test for cables made in accordance 

with known prior art methods and discover that the cable 

has that certain performance characteristic. 

First, we agree with Southwire that 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.” 

Honeywell Int’l v. Mexichem Amanco Holding S.A., No. 

2016-1996, —F.3d—, 2017 WL 3254943, at *10 (Fed. Cir. 

Aug. 1, 2017) (quoting In re Rijckaert, 9 F.3d 1531, 1534 

(Fed. Cir. 1993)). While “[w]e have recognized that inherency may supply a missing claim limitation in an obviousness analysis,” PAR Pharm., Inc. v. TWI Pharm., Inc., 

773 F.3d 1186, 1194–95 (Fed. Cir. 2014) (collecting cases), 

we have emphasized that “the limitation at issue necessarily must be present” in order to be inherently disclosed

by the reference, id. (emphasis added). The Board cited 

no evidence that a reduction of 30% in the pulling force 

would necessarily result from the claimed process, which 

contains no steps that ensure such reduction. 

Here, the Board found that because the claims recite 

“a preselected lubricant” chosen to “provide a reduced 

coefficient of friction,” they “require an amount of lubricant which meets the stated reduction in [coefficient of 

friction].” It found that, because Summers teaches reducing the coefficient of friction using a lubricant, Summers

inherently teaches the 30% reduction limitation because 
8 SOUTHWIRE CO. v. CERRO WIRE LLC

Summers renders it “obvious to have selected [lubricant] 

amounts” that achieve that result. Final Decision, 2015 

Pat. App. LEXIS 10285, at *16 (emphasis added). We 

conclude that the Board erred in relying on inherency 

without finding that Summers necessarily would achieve a 

30% reduction in pulling force, but rather finding that it 

merely renders that limitation obvious.

However, we also conclude that the Board’s error was 

harmless because, although it improperly invoked inherency, it need not have. It made the necessary underlying 

factual findings to support an obviousness determination. 

It found that the claimed method simply applies the same 

process for the same purpose as disclosed in Summers—

i.e., to reduce the pulling force on a cable for ease of

installation. See, e.g., J.A. 169. 

The Board found that Summers discloses an “identical 

or substantially identical” process to that claimed in the 

’301 patent. Final Decision, 2015 Pat. App. LEXIS 10285, 

at *12. It found that Summers teaches that a “fiber optic 

cable . . . is extruded with [a] cable jacket . . . formed from 

plastic material (e.g., polyethylene) containing a lubricant 

(e.g., fatty acid[] compounds, silicon oils, or fluorocompounds), with such lubricant characterized by migrating to the surface of [the] cable jackets . . . and lubricating 

the interface between the cable jackets and virtually any 

surface of or in the cable passageway.” Id. at *12–13. 

Those findings are supported by substantial record evidence. See, e.g., J.A. 169–70.

None of the patented steps differs in any material way 

from the process disclosed in Summers (in view of Dow). 

And there is no evidence that the claimed 30% reduction

in pulling force would have been unexpected or unattainable from the process disclosed in Summers. In fact, there 

is no evidence that the process disclosed in Summers did 

not produce an “at least . . . 30% reduction” in pulling 

force. Our predecessor court has held that where “all 
SOUTHWIRE CO. v. CERRO WIRE LLC 9

process limitations . . . are expressly disclosed by [the prior 

art reference], except for the functionally expressed [limitation at issue],” the PTO can require an applicant “to 

prove that the subject matter shown to be in the prior art 

does not possess the characteristic relied on.” In re Best, 

562 F.2d 1252, 1254–55 (CCPA 1977) (emphases added)

(internal quotation marks omitted). The court noted that 

“[w]hether the rejection is based on ‘inherency’ under 35 

U.S.C. § 102, [or] on ‘prima facie obviousness’ under 35 

U.S.C. § 103, . . . the burden of proof is the same.” Id.

Simply because Summers never quantified the reduction in pulling force achieved by its disclosed embodiments does not preclude the possibility, or even 

likelihood, that its process achieved at least a 30% reduction, especially since its stated purpose was the same as 

that of the ’301 patent—to reduce the pulling force on the 

cable for ease of installation. See, e.g., J.A. 169. In the 

absence of any evidence that the claimed 30% reduction

would have been unexpected in light of the Summers

disclosure, there is no indication that the limitation is

anything other than mere quantification of the results of 

a known process.

Furthermore, the 30% reduction limitation was added 

to the claim by amendment in a previous reexamination

in order to overcome the prior art, J.A. 3–4, 58–60, with 

seemingly no focus on that limitation in the original

written description. Other than a single mention that, 

under a certain test, “lubricated specimens” (the details of 

which are undisclosed) yielded a 50% reduction in pulling 

force compared to non-lubricated standards, ’301 patent 

col. 6 ll. 20–24, the written description provides no discussion regarding the amount of reduction in pulling force; it

merely teaches that one can reduce the pulling force by 

incorporating certain lubricants into the cable sheath, as 

taught by Summers. Thus, neither the patent itself nor 

any evidence proffered by Southwire during the reexamination provides any indication that the “at least about a 
10 SOUTHWIRE CO. v. CERRO WIRE LLC

30% reduction” limitation was something other than an 

observed result of an old process, written into the claim in 

an attempt to avoid the prior art process. 

In sum, the Board’s underlying factual findings are 

supported by substantial evidence and reasonably support 

its conclusion that it would have been “obvious to have 

selected such amounts” as would achieve the claimed 

reduction in pulling force because “the claims require an 

amount of lubricant which meets the stated reduction in 

[coefficient of friction]” and “Summers teaches reducing 

the coefficient of friction” using the same process, for the 

same purpose. Final Decision, 2015 Pat. App. LEXIS 

10285, at *16.

Southwire also argues that the Board erred in acknowledging that Southwire’s evidence shows a long-felt 

need, but then disregarding the evidence by finding that 

the prior art solved that need. Southwire argues that 

such an approach is circular and would render consideration of long-felt need a dead letter. Under that reasoning, 

Southwire contends, every time the Board finds that a 

reference teaches a limitation, there could never be a 

long-felt need, as the reference purportedly already provided a solution. 

Cerro responds that the Board correctly rejected 

Southwire’s objective evidence because the declarations 

provided do not relate specifically to the claims at issue 

and they contain no proof of a nexus to any of the claim 

limitations. And, Cerro continues, the Board correctly 

characterized the problem to be solved broadly, because 

that characterization is supported by the ’301 patent 

itself. Under that broad characterization, Cerro contends, 

Summers indisputably provided several solutions before 

the ’301 patent’s priority date. It taught using cable 

sheaths with irregular surface characteristics, as well as 

the claimed solution of lubricants incorporated into the 

sheath.
SOUTHWIRE CO. v. CERRO WIRE LLC 11

We agree with Cerro. Substantial evidence supports 

the Board’s findings that Southwire’s evidence lacked

factual support, that its objective evidence lacked a nexus 

to the claimed invention, and that any long-felt need 

adduced from the evidence had already been met by 

Summers. We see no legal error in its analysis.

CONCLUSION

We have considered the parties’ remaining arguments 

but find them to be unpersuasive. For the foregoing 

reasons, we affirm the decision of the Board.

AFFIRMED