          NOTE: This disposition is nonprecedential.


  United States Court of Appeals
      for the Federal Circuit
                 ______________________

           POLYGROUP LIMITED MCO,
               Plaintiff-Appellant

                             v.

        WILLIS ELECTRIC COMPANY, LTD,
                Defendant-Appellee
              ______________________

           2018-1748, 2018-1749, 2018-1750
               ______________________

   Appeals from the United States Patent and Trade-
mark Office, Patent Trial and Appeal Board in Case Nos.
IPR2016-01615, IPR2016-01616, and IPR2016-01617.
                ______________________

               Decided: January 28, 2019
                ______________________

   ROBERT A. ANGLE, Troutman Sanders LLP, Richmond,
VA, argued for appellant. Also represented by DABNEY
JEFFERSON CARR, IV, CHRISTOPHER FORSTNER, LAURA
ANNE KUYKENDALL; DOUGLAS SALYERS, Atlanta, GA.

  LARINA A. ALTON, Fox Rothschild LLP, Minneapolis,
MN, argued for appellee.
                ______________________

    Before DYK, REYNA, and HUGHES, Circuit Judges.
2                POLYGROUP LTD MCO    v. WILLIS ELEC. CO., LTD



HUGHES, Circuit Judge.
    This is a patent case involving lighted artificial trees.
Polygroup Ltd. MCO petitioned for inter partes review of
U.S. Patent No. 8,936,379. The Patent Trial and Appeal
Board instituted review of all challenged claims. The
Board determined that Polygroup had not established the
unpatentability of any of the challenged claims. Poly-
group now appeals. Because the Board did not err in
finding that Korengold does not teach an “interference fit”
under the broadest reasonable interpretation of that term,
we affirm the Board’s determination that claims 12, 15,
and 32 were not shown to be unpatentable. But, we find
that the Board erred in construing “modular artificial
tree” and erred in finding that Polygroup failed to estab-
lish a motivation to combine the asserted prior art. As a
result, we vacate the Board’s determination that claims
1–6, 8, 10–11, 13–14, 16–17, and 28–29 were not shown to
be unpatentable. On remand, the Board should consider
whether those claims are unpatentable under a proper
construction.
                              I
                             A.
    Willis Electric Co., Ltd. owns the ’379 patent, which is
directed to a lighted artificial tree. The tree is comprised
of “separable, modular tree portions mechanically and
electrically connectable between trunk portions.” ’379
patent col. 1 ll. 13–15. The hollow trunk portions contain
electrical wiring and electrical connectors that provide a
source of electricity for light strings draped over the
branches. The connectors are designed so that mechani-
cally connecting trunk portions during assembly also
creates an electrical connection between the trunk por-
tions. The connectors form an electrical connection re-
gardless of the rotational alignment of the trunk portions.
These features simplify tree assembly by removing the
need for “significant manipulation and handling of the
POLYGROUP LTD MCO   v. WILLIS ELEC. CO., LTD                 3



tree sections to securely align and couple the sections
together.” ’379 patent col. 2 ll. 26–28.
    The ’379 patent relates to the patents at issue in our
companion case, Polygroup Ltd. v. Willis Elec. Co., No. 18-
1745, slip op. (Fed. Cir. Jan. 28, 2019), but the ’379 patent
focuses more specifically on the structure and positioning
of the mechanical-electrical connectors within the trunk
sections. Independent claims 1 and 5 are representative
of the challenged claims and are reproduced below.
    1. A modular artificial tree, comprising:
    a first trunk portion having a first elongated
    trunk body defining a first cavity for receiving a
    first wiring harness including a first electrical
    wire and a second electrical wire;
    a second trunk portion having a second elongated
    trunk body defining a second cavity for receiving a
    second wiring harness including a first electrical
    wire and a second electrical wire;
    a first trunk connector insertable into the first
    trunk body along a central vertical axis, and se-
    curable to the first trunk body in at least four ro-
    tational alignment positions about the central
    vertical axis, including at a final insertion posi-
    tion, the first trunk connector being entirely lo-
    cated within the first cavity at the final insertion
    position[;]
    a first electrical contact set including a first elec-
    trical contact and a second electrical contact en-
    gaged with the first trunk connector and
    electrically connected to the first electrical wire
    and the second electrical wire of the first wiring
    harness, respectively;
    a second trunk connector insertable into the sec-
    ond trunk body along the central vertical axis, and
4                 POLYGROUP LTD MCO   v. WILLIS ELEC. CO., LTD



    securable to the second trunk body in at least four
    rotational alignment positions about the central
    vertical axis, including at a final insertion posi-
    tion;
    a second electrical contact set including a first
    electrical contact and a second electrical contact
    engaged with the second trunk connector and
    electrically connected to the first electrical wire
    and the second electrical wire of the second wiring
    harness, respectively; and
    wherein connecting the first and second trunk
    portions causes the first electrical contact set to be
    electrically connected to the second electrical con-
    tact set.
’379 patent col. 23 l. 63–col. 24 l. 30 (emphasis added).
    5. A lighted modular artificial tree, comprising:
    a first tree section including a first elongated
    trunk defining a vertical axis, a plurality of
    branches coupled to the first trunk, and a first
    plurality of lights, the first elongated trunk en-
    closing a first wiring harness configured to supply
    power to the first plurality of lights;
    a second tree section including a second elongated
    trunk, a plurality of branches coupled to the sec-
    ond trunk, and a second plurality of lights, the
    second elongated trunk housing a second wiring
    harness;
    a connector assembly configured to connect the
    first tree section to the second tree section along
    the vertical axis, the connector assembly including
    a first trunk connector located at least partially
    within the first trunk, a second trunk connector
    located at least partially within the second trunk,
POLYGROUP LTD MCO    v. WILLIS ELEC. CO., LTD                  5



    a first pair of electrical contacts electrically con-
    nectable to a second pair of electrical contacts;
    a top tree section including a vertically extending
    top portion, a plurality of branches coupled to the
    top portion, and a third plurality of lights, and a
    top connector connecting the top tree section to
    the second tree section and including:
    a top connector body having a first portion insert-
    able into the second trunk, a flanged portion cou-
    pled to the first portion, and a receiving port for
    receiving a portion of the vertically extending top
    portion, and
    wherein the first plurality of lights are electrically
    connected to the second plurality of lights through
    the connector assembly, and the second plurality
    of lights are electrically connected to the third
    plurality of lights and,
    wherein the flanged portion of the top connector
    body is outside the second trunk body and abut-
    ting a top edge of the second trunk portion.
’379 patent col. 24 l. 51–col. 25 l. 16 (emphasis added).
    The preamble of each challenged claim recites a
“modular artificial tree.” Claims 1, 17, and 29 require
that the connector fit into the trunk body “in at least four
rotational alignment positions about the central vertical
axis.” ’379 patent col. 24 ll. 20–21; see also id. at col. 26 ll.
3–5; id. at col. 28 ll. 33–34. Although none of the claims
here recite the “tree portion” limitation at issue in our
companion case, see Polygroup, No. 18-1745, slip op. at 4,
claim 5 recites multiple “tree sections.” And the Board
construed “tree section” identically to “tree portion.” See
id. at 7 (noting that the Board construed “tree portion” to
mean “a mechanically and electrically connectable modu-
lar and unitary portion of an artificial tree”). Claims 12,
15, and 32 depend from claims 1, 5, and 28 respectively,
6                POLYGROUP LTD MCO   v. WILLIS ELEC. CO., LTD



and each adds the limitation of an “interference fit”
formed between the trunk connector and the trunk body.
                            B.
    Polygroup Ltd. filed three petitions for IPR of the ’379
patent alleging obviousness based on different combina-
tions of prior art references. The Board instituted review
on all challenged grounds in three separate IPR proceed-
ings.
    Polygroup’s petitions rely on six prior art references,
three of which are relevant here: U.S. Patent No.
4,072,857 (DeVicaris), U.S. Patent No. 2,229,211 (Koren-
gold), and U.S. Patent Application Publication No.
2007/0230174 A1 (Hicks).
    Polygroup relies on DeVicaris for each of its asserted
grounds. DeVicaris is directed to an artificial tree with
hollow trunk sections that contain electrical wiring and
have electrical-mechanical connectors for attaching the
trunk sections. During assembly, the trunk sections must
be aligned in a single rotational position about the verti-
cal axis. The branches in DeVicaris are detachable from
the trunk sections, and the tree is assembled by first
connecting the trunk sections, and then attaching the
branches to the trunk.
    Polygroup relies on Korengold to teach both the
“interference fit” limitation in claims 12, 15, and 32, and
the “four rotational alignment positions” limitation in
claims 1, 17, and 29. Korengold is directed to an electrical
connector used to supply power between conduit pipe
sections in an electrical device with multiple tubular
parts, such as a modular lamp. The external diameter of
the connector is “substantially equivalent” to the internal
diameter of the pipe, which allows the connectors to form
a “snug fitting” when inserted into the pipe. J.A. 1100.
Polygroup argues that Korengold’s “snug fit[]” is equiva-
lent to the “interference fit” in the ’379 patent. Polygroup
POLYGROUP LTD MCO   v. WILLIS ELEC. CO., LTD                7



also argues that a person of ordinary skill in the art
would have been motivated to apply the type of connec-
tion taught by Korengold to the connectors in DeVicaris,
resulting in a “connector . . . securable to the [] trunk body
in at least four rotational alignment positions.” ’379
patent col. 24 ll. 18–21.
    Polygroup relies on Hicks for the obviousness of
claims 5, 10, 11, and 15–17. Hicks discloses an artificial
tree with hollow trunk members that house the light
wiring system. Hicks also teaches removable branches,
each having its own electrical connector. Electricity is
provided to the light strings on each branch individually,
so that a branch can be removed and replaced without
affecting lights on other branches.
                             C.
    The Board issued a consolidated decision for the three
IPRs challenging the ’379 patent. A majority of the Board
found that Polygroup failed to prove by a preponderance
of the evidence that any of the challenged claims are
unpatentable. 1
    The Board first addressed the construction of “modu-
lar artificial tree” recited in the preamble of each claim.
The Board found the preamble to be limiting, and it
construed “modular artificial tree” to mean “a tree con-
structed of modular portions, each modular portion being
a separate tree section.” J.A. 14. Crediting the testimony
of Willis’s expert, the Board found that a “person having
ordinary skill in the art ‘recognizes modular’ as a ‘distinct’
type of artificial tree with tree sections that come ‘with
branches pre-attached to the trunk’ so that assembly is
‘quick and easy.’” J.A. 19. Accordingly, the Board found


    1  A single member of the Board dissented and
would have found all challenged claims unpatentable as
obvious under 35 U.S.C. § 103.
8                POLYGROUP LTD MCO   v. WILLIS ELEC. CO., LTD



that neither DeVicaris nor Hicks teaches a “modular
artificial tree” because the branches of each are separate-
ly attached to the trunk sections. Because every chal-
lenged claim recites a “modular artificial tree,” and
Polygroup failed to provide a prior art reference teaching
that limitation, the Board found that Polygroup failed to
prove that any of the challenged claims are unpatentable.
    As an alternate basis for its patentability determina-
tions as to claims 12, 15, and 32, the Board found that
Korengold fails to teach an “interference fit” as required
by those claims. The Board construed “interference fit” to
mean “an engineered connection where two components or
parts to be connected are manufactured to be of different
dimensions such that when one component is pressed into
the other, they interfere and deform to force a connec-
tion.” J.A. 30. The Board concluded that Polygroup failed
to show that Korengold’s “snug fit” between two parts
with “substantially equivalent” diameters teaches a fit
where parts “interfere to force a connection so as to secure
the connection.” J.A. 47.
     As an alternate basis for its patentability determina-
tions as to claims 1, 2–4, 6, 8, 13, 14, 17, and 29, the
Board found that Polygroup failed to establish that a
skilled artisan would have been motivated to combine
DeVicaris with Korengold. Polygroup argued a person of
ordinary skill would have been motivated to combine the
references because the “ease of assembly [of DeVicaris] is
improved because of the rotational freedom afforded by
Korengold’s interference-fit connection.” J.A. 39. Accord-
ing to the Board, Polygroup failed to show that Korengold
teaches rotational freedom. Additionally, because Koren-
gold does not teach an “interference fit,” the Board con-
cluded that a skilled artisan would not look to Korengold
for such a fit.
   Polygroup now appeals. We have jurisdiction under
28 U.S.C. § 1295(a)(4)(A).
POLYGROUP LTD MCO    v. WILLIS ELEC. CO., LTD                 9



                               II
     We first consider the Board’s claim constructions of
“modular artificial tree” and “interference fit.” We review
the Board’s ultimate claim construction de novo and any
underlying factual determinations involving extrinsic
evidence for substantial evidence. In re Cuozzo Speed
Techs., LLC, 793 F.3d 1268, 1280 (Fed. Cir. 2015). Sub-
stantial evidence requires that “a reasonable mind might
accept the evidence to support the finding.” In re Giannel-
li, 739 F.3d 1375, 1379 (Fed. Cir. 2014).
    During IPR of an unexpired patent, the Board gives
the claims their broadest reasonable interpretation in
light of the specification. 37 C.F.R. § 42.100(b). Under
this standard, claim terms are generally given their
ordinary and customary meaning, as would be understood
by a skilled artisan in the context of the entire disclosure.
See In re Translogic Tech., Inc., 504 F.3d 1249, 1257 (Fed.
Cir. 2007).
     For the reasons below, we find the Board erred in its
construction of “modular artificial tree,” but it did not err
in its construction of “interference fit.”
                              A.
     The Board found the recitation of “modular artificial
tree” in the preamble of each claim to be limiting because
it “provides necessary context at least for the terms ‘trunk
portion’ and ‘tree section,’ and how they interface with
each other.” J.A. 12. The Board then construed “modular
artificial tree” to mean “a tree constructed of modular
portions, each modular portion being a separate tree
section.” J.A. 11. Relying on the testimony of Willis’s
expert, Dr. Brown, the Board concluded that a modular
tree is “a ‘distinct’ type of artificial tree with tree sections
that come ‘with branches pre-attached to the trunk.’” J.A.
19. This conclusion was error because the Board’s con-
10               POLYGROUP LTD MCO    v. WILLIS ELEC. CO., LTD



struction does not represent the broadest reasonable
interpretation of “modular artificial tree.”
    First, we note that other than claim 5, none of the in-
dependent claims of the ’379 patent recite branches. We
find no support for reading such a limitation into the
claims as the Board did here. See Phillips v. AWH Corp.,
415 F.3d 1303, 1320 (Fed. Cir. 2005) (cautioning against
reading limitations from the specification into the claims).
     Additionally, while the ’379 patent’s specification dis-
closes “modular tree portions” in the Field of Invention,
see ’379 patent col. 1 l. 14, it also describes other aspects
of the tree as “modular” throughout the specification, such
as the connector assembly and light system, see id. at col.
18 l. 36 (noting the “modularity and detachability of
connector assembly 200”); id. at col. 20 ll. 50–53 (discuss-
ing the “modularity” of the lighting system). Given these
disclosures, we are not persuaded that the broadest
reasonable interpretation of “modular artificial tree”
requires a tree with “tree sections that come ‘with
branches pre-attached to the trunk.’” J.A. 15. Instead,
we find Polygroup’s proposed construction, “an artificial
tree with elements capable of being easily joined or ar-
ranged with other parts or units,” to be more consistent
with the entire disclosure of the ’379 patent. J.A. 11.
    To the extent the Board relied on Dr. Brown’s testi-
mony in reaching its construction, the Board erred in
doing so. While it can be proper to rely on expert testi-
mony “to establish that a particular term in the patent . . .
has a particular meaning in the pertinent field[,] . . .
conclusory, unsupported assertions by experts as to the
definition of a claim term are not useful” during claim
construction. Phillips, 415 F.3d at 1318. Dr. Brown’s
statement is a conclusory and unsupported assertion, and
we find it to be inconsistent with the intrinsic record. So,
his testimony does not provide substantial evidentiary
POLYGROUP LTD MCO   v. WILLIS ELEC. CO., LTD              11



support for the Board’s conclusion that a modular tree is
one with “branches pre-attached to the trunk.” J.A. 15.
     Because the Board’s determinations on the patentabil-
ity of claims 1–6, 8, 10–11, 13–14, 16–17, and 28–29 relied
solely on its erroneous construction of “modular artificial
tree,” we vacate those determinations and remand to the
Board for consideration of whether those claims are
obvious under a proper construction. 2
                               B.
    The Board construed “interference fit” to mean “an
engineered connection where two components or parts to
be connected are manufactured to be of different dimen-
sions such that when one component is pressed into the
other, they interfere and deform to force a connection.”
J.A. 30. The Board emphasized that the key to an inter-
ference fit is that the difference in dimensions forces a
connection that “is strong enough to cause the two pieces
to remain fixed relative to each other.” J.A. 22. The
Board rejected Polygroup’s proposed construction, “a fit
between two parts in which the external dimension of one
part slightly exceeds the internal dimension of the part
into which it has to fit,” J.A. 22, because it is “uncon-
cerned with whether the two parts are fixed relative to
each other, and is only concerned with whether they are
somewhat different in size.” J.A. 23.




    2   The Board also found that Hicks does not disclose
the “tree section” limitation of claim 5. The Board con-
strued “tree section” to have the same meaning as “tree
portion,” a limitation in the related patents at issue in our
companion case. See Polygroup, No. 18-1745, slip op. at 7.
Because we found that the Board erred in construing “tree
portion” in that case, id. at 10, we find that the Board
erred in construing “tree section” here.
12               POLYGROUP LTD MCO    v. WILLIS ELEC. CO., LTD



    We find that the Board’s construction reflects the
broadest reasonable interpretation of “interference fit”
given the ’379 patent’s specification. The specification
describes the “interference fit” between the connector and
the trunk wall as one where “force is exerted” so that the
parts are “held together.” See ’379 patent col. 12 l. 66–col.
13 l. 2; see also id. at col. 13 ll. 62–65. The specification
also explains that the parts or components “deform” in
order to fit the connector “inside [the] base-trunk portion,”
and that “[s]uch deformation or compression” forms an
“interference fit.” Id. at col. 16 ll. 1–4. Thus, we agree
with the Board that the key consideration for an “inter-
ference fit” is the connection generated between the parts
and whether the parts deform to force a connection, not
whether the difference in their diameters is slight or
substantial.
    Because we find no error in the Board’s claim con-
struction of “interference fit,” we also find that the
Board’s determination that Korengold does not teach an
“interference fit” is supported by substantial evidence.
Korengold teaches a “snug fit[]” formed by parts with
“substantially equivalent” diameters. J.A. 1100. Nothing
in its disclosure teaches that the parts “interfere [and
deform] to force a connection.” See J.A. 47. Nor does
Korengold require that the external diameter of the
connector exceeds the internal diameter of the pipe.
Thus, Korengold fails to teach an interference fit even
under Polygroup’s proposed construction, which requires
that the external dimension of one part “slightly exceeds”
the internal dimension of the part into which it is to fit.
See J.A. 22.
                             III
     Next, we consider the Board’s finding that Polygroup
failed to establish that a skilled artisan would have been
motivated to combine DeVicaris with Korengold. A party
asserting that a claimed invention is obvious “must
POLYGROUP LTD MCO   v. WILLIS ELEC. CO., LTD               13



demonstrate . . . that a skilled artisan would have had
reason to combine the teaching of the prior art references
to achieve the claimed invention, and that the skilled
artisan would have had a reasonable expectation of suc-
cess from doing so.” PAR Pharm., Inc. v. TWI Pharm,
Inc., 773 F.3d 1186, 1193 (Fed. Cir. 2014) (internal quota-
tion marks omitted). Whether a person of ordinary skill
would have been motivated to combine the prior art is a
factual question reviewed for substantial evidence.
Intercontinental Great Brands LLC v. Kellogg N. Am. Co.,
869 F.3d 1336, 1343 (Fed. Cir. 2017); see also In re Gian-
nelli, 739 F.3d at 1379.
     In its petition, Polygroup argued that a skilled artisan
would have been motivated to enhance the tree from
DeVicaris with the “interference fit-type connection”
taught by Korengold. J.A. 160. According to Polygroup,
“[t]he rotational freedom afforded by Korengold’s interfer-
ence fit-type connection would permit the . . . electrical
connectors of DeVicaris to be inserted into, and secured
within, respective trunk sections in any rotational align-
ment position.” Id.
    The Board rejected Polygroup’s proposed motivation.
The Board found that Korengold does not teach rotational
freedom because “an electrical connector assembly within
a conduit pipe . . . does not in itself teach rotational free-
dom.” J.A. 40. Further, because the Board determined
that Korengold does not teach an “interference fit,” it
found that a skilled artisan would not look to Korengold
for such a fit. The Board also found that a person of
ordinary skill would not have been motivated to replace
the connectors in DeVicaris with the connectors in Koren-
gold. Given the record before us, we conclude that the
Board’s rejection of Polygroup’s proposed motivation is
not supported by substantial evidence for three reasons.
   First, the Board’s determination that a skilled artisan
would not replace the connectors in DeVicaris with the
14               POLYGROUP LTD MCO   v. WILLIS ELEC. CO., LTD



connectors from Korengold is irrelevant to the motivation
actually proposed by Polygroup. Polygroup suggested
enhancing DeVicaris with the connection used to insert
Korengold’s connectors into the conduit pipe, not the
connectors themselves. Because most of the Board’s
analysis, and the expert testimony it relied upon, focused
on the motivation to replace DeVicaris’s connector with
Korengold’s connector, neither that analysis nor the
expert testimony provides substantial evidentiary support
for the Board’s rejection of Polygroup’s proposed motiva-
tion. See J.A. 41–43 (focusing on the finding that replac-
ing DeVicaris’s connector with Korengold’s connector
would make tree assembly more difficult).
     Second, the fact that Korengold does not teach an “in-
terference fit” as that term is used in claims 12, 15, and
32 is also irrelevant to the motivation to combine analy-
sis. Polygroup argues that a skilled artisan would look to
Korengold’s connection because it teaches rotational
freedom. Polygroup’s choice to refer to Korengold’s con-
nection as an “interference fit-type connection” has no
bearing on whether Korengold teaches rotational freedom,
so it also has no bearing on whether a skilled artisan
would have been motivated in the manner Polygroup
proposes. That Korengold does not teach an “interference
fit” is only relevant to the patentability of claims 12, 15,
and 32, which include that limitation.
     Finally, the Board’s determination that Korengold
fails to teach rotational freedom is not supported by
substantial evidence. Korengold discloses a cylindrical
connector that is inserted into a cylindrical pipe with a
“substantially equivalent” diameter such that the two
parts form a “snug fitting.” J.A. 1100. Such an arrange-
ment would allow the connector to be inserted in “any
rotational alignment position,” as Polygroup’s expert
asserted. J.A. 1020. Nowhere does Korengold suggest
that its connectors require a particular rotational align-
ment. Thus, no reasonable fact finder could conclude that
POLYGROUP LTD MCO   v. WILLIS ELEC. CO., LTD           15



Korengold fails to teach a connection with rotational
freedom. And we agree with Polygroup that a person of
ordinary skill would have been motivated to enhance
DeVicaris with Korengold because Korengold’s rotational
freedom would improve the ease of assembly of the De-
Vicaris tree.
                             IV
    We have considered the parties’ remaining arguments
and find them unpersuasive. We conclude that the Board
erred in its construction of “modular artificial tree” and
that Polygroup established a sufficient motivation to
combine DeVicaris with Korengold. Therefore, we vacate
the Board’s determination that Polygroup failed to prove
that claims 1–6, 8, 10–11, 13–14, 16–17, and 28–29 are
not unpatentable. On remand, the Board should consider
whether those claims are unpatentable under a proper
construction. We affirm the Board’s determination that
Polygroup failed to prove that claims 12, 15, or 32 are
unpatentable because Korengold fails to teach an “inter-
ference fit” under the broadest reasonable interpretation
of that term.
  AFFIRMED-IN-PART, VACATED-IN-PART, AND
                REMANDED
                           COSTS
   No costs.
