Acufloor, LLC v. Eventile, Inc., Forpac, LLC

N OTE : This disposition is nonprecedential.
United States Court of Appeals
for the Federal Circuit
______________________
ACUFLOOR, LLC,
Plaintiff-Appellant
v.
EVENTILE, INC., FORPAC, LLC,
Defendants-Appellees
______________________
2023-1887
______________________
Appeal from the United States District Court for the
Middle District of Florida in No. 2:21-cv-00802-SPC-KCD,
Judge Sheri Polster Chappell.
______________________
Decided: May 28, 2025
______________________
DEBRA J ANECE MCC OMAS, Haynes and Boone, LLP,
Dallas, TX, argued for plaintiff-appellant. Also repre-
sented by J OHN R USSELL EMERSON, CAROLINE W. F OX;
A DAM L LOYD ERICKSON, A NGELA M. OLIVER , Washington,
DC.
R OBERT MANHAS, Orrick, Herrington & Sutcliffe LLP,
Washington, DC, argued for all defendants-appellees. De-
fendant-appellee Eventile, Inc. also represented by PERRY
S. C LEGG, Johnson & Martin, P.A., Salt Lake City, UT.
Case: 23-1887 Document: 57 Page: 1 Filed: 05/28/2025

-- 1 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 2
Defendant-Appellee Forpac, LLC also represented by
WILLIAM J OHN EAGAN, Malloy & Malloy P.L, Miami, FL.
______________________
Before L OURIE , BRYSON, and STARK, Circuit Judges.
Opinion for the court filed by Circuit Judge BRYSON.
Opinion concurring-in-part and dissenting-in-part filed by
Circuit Judge STARK.
B RYSON, Circuit Judge.
Acufloor, LLC, brought this action against EvenTile,
Inc., and FORPAC, LLC, alleging that EvenTile and
FORPAC have infringed two of Acufloor’s patents. Follow-
ing the district court’s claim construction order, the parties
stipulated to a judgment of non-infringement. Acufloor
now appeals two of the district court’s claim constructions.
We modify one of the claim constructions and reject the
other. We therefore vacate the judgment and remand for
further proceedings.
I
A
Acufloor has asserted U.S. Patent Nos. 10,704,274
(“the ’274 patent”) and 10,513,857 (“the ’857 patent”)
against the defendants in this case. The patents, which
share a common specification, are directed to devices used
for leveling, aligning, and properly spacing tiles. See ’274
patent, col. 1, ll. 48–49.1 Ceramic tile installers often use
such devices to avoid lippage, a condition in which the edge
of one tile is higher or lower than the edge of an adjoining
tile.
When laying tile using the patented device, a tile in-
staller spreads mortar over the subfloor where the tiles are
1 For convenience, this opinion cites to the specifica-
tion of the ’274 patent throughout.
Case: 23-1887 Document: 57 Page: 2 Filed: 05/28/2025

-- 2 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 3
to be installed and then places a tile on the mortar-covered
subfloor. Next, the installer inserts one side of the horizon-
tal base of the tile clip under the tile. See id. at Fig. 6. The
installer then places a second tile on top of the other side
of the base of the clip so that the upright body of the clip is
positioned between the two tiles. See id. at Fig. 7. The
installer then places a wedge, the other component of the
tile-leveling system, through an opening in the body of the
tile clip. When fully inserted, the wedge presses down on
the two tiles to level them. See id. at Fig. 8. Once the tiles
are set, the installer removes the wedge by breaking the
body of the clip at a breaking point in the base. The in-
staller then repeats the process with other sets of tiles. See
id. at Fig. 9.
A depiction of an exemplary embodiment of the clip and
wedge devices is found in Figures 11A and 11B of the ’274
specification, which are reproduced below:
Case: 23-1887 Document: 57 Page: 3 Filed: 05/28/2025

-- 3 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 4
The I-shaped base of the tile clip (122) depicted in Fig-
ure 11A includes structures 124, 126, 128, and 130, two of
which extend under each of the adjacent tiles. Structure
110 is the body of the clip, which extends upward between
the tiles when the clip is in the intended position. Struc-
tures 118 and 120 are two stems of the body that intersect
the base and define an open window in the body (116).2
Structure 152 and its unnumbered equivalent on the other
stem of the body are spacing pads that are attached to the
stems of the body and can be used to position the tiles at a
predetermined distance apart. Id. at col. 5, ll. 65–67.3
Structure 112, which is depicted in Figure 11B, is the
wedge device that is inserted in the opening (or window) in
the body (structure 116) of the tile clip to press the tiles
into a level configuration. Structures 140 and 142 are the
narrow portions of the body, which define the location at
which the body snaps off from the base of the clip when the
leveling process is completed.
The ’274 and ’857 patents disclose various shapes for
the clip and wedge devices. All of the clips have a pair of
2 Figure 11A is misleading in that structure 116,
which the specification describes as the open window, ’274
patent, col. 5, ll. 46, 62, 65 & col. 6, l. 11, seems to point to
a spacing pad, which is otherwise designated as structure
152.3 The relationship between the stems and the spac-
ing pads is easier to see in Figure 2 of the ’274 patent,
which depicts a side view of the clip with the wedge device
inserted through the open window. In that figure, the stem
is designated as 21 and the spacing pad is designated as
30. The specification explains that the spacing pad “con-
tributes to furnishing a combination of vertical leveling
and joint spacing within a single product.” ’274 patent, col.
3, ll. 23–30.
Case: 23-1887 Document: 57 Page: 4 Filed: 05/28/2025

-- 4 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 5
notches4 in the base, which allow more of the surface area
of the tile to be in direct contact with the mortar that is
spread over the subfloor. See id. at Fig. 11A.
The common specification explains that a single level-
ing device and wedge can be used to align two, three, or
four tiles at once. See id. at col. 3, ll. 43–47; col. 6, ll. 12–
14; Figs. 3–5. In the four-tile embodiment, “each tile has
corner-to-subfloor contact due to the notches that provide
space for mortar contact therein.” Id. at col. 6, ll. 15–18.
In a two-tile implementation, “each tile has edge-to-sub-
floor contact due to the notches.” Id. at col. 6, ll. 18–19.
B
Claims 5 and 8 of the ’274 patent are generally repre-
sentative of the claims of that patent for purposes of this
appeal. Claim 5 recites:
5. A tile leveling device comprising:
a body defining an open window;
a base orthogonally coupled to the body, the
base extending to the front of the body and the
base extending to the rear of the body;
a base to body coupling including a frangible
breakaway section, the base and body being
integral prior to frangible separation, the
frangible breakaway section, upon breaking,
frangibly separating the body from the base;
a first notch formed at the base extending
from proximate the base to body coupling to
the front of the body the first notch providing
4 The district court construed the term “notch” to
mean an “opening intersecting an edge of the base through
which mortar can penetrate.” App. 8. That construction is
not challenged on appeal.
Case: 23-1887 Document: 57 Page: 5 Filed: 05/28/2025

-- 5 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 6
first tile edge-to-mortar-to-subfloor contact;
and
a second notch formed at the base extending
from proximate the base to body coupling to
the rear of the body the second notch provid-
ing first tile edge-to-mortar-to-subfloor con-
tact; and
the combination of the first notch and the sec-
ond notch providing a majority of an area of
tile-to-mortar-to-subfloor contact for the level-
ing device within the bounds of the base.
’274 patent, cl. 5 (the emphasized text denotes the disputed
limitations). Claim 8 recites:
8. A tile leveling device comprising:
a body defining an open window;
a base orthogonally coupled to the body, the
base extending to the front of the body and the
base extending to the rear of the body;
a base to body coupling including a frangible
breakaway section, the base and body being
integral prior to frangible separation, the
frangible breakaway section, upon breaking,
frangibly separating the body from the base;
a first notch formed at the base extending
from proximate the base to body coupling to
the front of the body; and
a second notch formed at the base extending
from proximate the base to body coupling to
the rear of the body; and
the combination of the first notch and the sec-
ond notch providing a majority of an area of
tile-to-mortar-to-subfloor contact for the level-
ing device within the bounds of the base.
Case: 23-1887 Document: 57 Page: 6 Filed: 05/28/2025

-- 6 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 7
’274 patent, cl. 8 (the emphasized text denotes the disputed
limitation).
Claim 10 of the ’857 patent is generally representative
of the claims of that patent for purposes of this appeal.
Claim 10 recites:
10. A tile leveling device comprising:
a body defining an open window;
an I-shaped base orthogonally coupled to the
body, the I-shaped base having spaced first,
second, third, and fourth bars extending
transversely from the body, the spaced first
and second bars extending to the front and
outward of the body and the spaced third and
fourth bars extending to the rear and outward
of the body;
an I-shaped base to body coupling including a
frangible breakaway section, the I-shaped
base and body being integral prior to frangible
separation, the frangible breakaway section,
upon breaking, frangibly separating the body
from the I-shaped base;
a first notch formed between the first and sec-
ond bars;
a second notch formed between the third and
fourth bars;
a first tile over the first bar, the first tile hav-
ing a first surface opposite a second surface,
the first tile having a first corner over the first
notch, the first corner having contact with
mortar at the first notch with edge-to-subfloor
contact of first corner-to-mortar-to-subfloor at
the first notch, wherein the first surface faces
the first bar and the second surface is farther
from the first bar than the first surface;
Case: 23-1887 Document: 57 Page: 7 Filed: 05/28/2025

-- 7 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 8
a second tile over the second bar, the second
tile having a third surface opposite a fourth
surface, the second tile having a second corner
over the first notch, the second corner having
contact with mortar at the first notch with
edge-to-subfloor contact of second corner-to-
mortar-to-subfloor at the first notch, wherein
the third surface faces the second bar and the
fourth surface is farther from the second bar
than the third surface; and
the frangible breakaway section being located
between the first and second surfaces of the
first tile and the third and fourth surfaces of
the second tile.
’857 patent, cl. 10 (the emphasized text denotes the dis-
puted limitations).
C
The prosecution histories of the ’857 and ’274 patents
are highly relevant to this appeal. During the prosecution
of U.S. Patent Application No. 16/102,207 (“the ’207 appli-
cation”), which matured into the ’857 patent, the examiner
initially rejected all the claims as obvious in view of two
references: U.S. Patent Application Publication No.
2008/0236094 (“Doda”) and U.S. Patent Application Publi-
cation No. 2013/0247508 (“Hoffman”). In response, the ap-
plicants amended the claims to add a limitation requiring
edge-to-subfloor contact, App. 701–08; they argued that the
proposed Doda-Hoffman combination did not disclose tile
edge-to-subfloor contact because the grooves of the Doda-
Hoffman combination “do not penetrate the base portion
and provide this type of edge-to-subfloor contact for the
tiles,” App. 709–10. In support of that argument, the ap-
plicants submitted an annotated diagram of the Hoffman
prior art reference, reproduced below. App. 1052. Refer-
ring to a plastic surface between the two grooves (1616) of
the Hoffman embodiment, the applicants’ annotation
states: “Edge of tile rests here. No edge-to subfloor
Case: 23-1887 Document: 57 Page: 8 Filed: 05/28/2025

-- 8 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 9
contact.” Id. In the accompanying remarks, the applicants
described the contact in Hoffman as “edge-to-groove” in
contrast to the claimed contact, which is “edge-to-subfloor.”
Id. In other words, the applications distinguished the Hoff-
man reference based on its lack of direct contact between
the edge of the tile and the subfloor, as required by the
claims in the application.
Id.
During the prosecution of U.S. Patent Application No.
16/102,344 (“the ’344 application”), which matured into the
’274 patent, the examiner issued a rejection for obviousness
based on Doda and International Publication No. WO
2013/033761 (“Psaila”). The Psaila device is depicted be-
low.
Case: 23-1887 Document: 57 Page: 9 Filed: 05/28/2025

-- 9 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 10
App. 835.
In the office action rejecting the claims, the examiner
explained that it would have been obvious to “modify the
base of Doda with the configuration of Psaila by extending
the opening 129 [in Doda] all the way to the front portion
of 116 for allowing more adhesive 132 to penetrate the
opening and extend over a greater surface area of the tiles
as taught by Psaila.” See App. 1309 (quoting June 14, 2019,
Non-final Rejection). The applicants responded by amend-
ing the claims to include a “tile edge-to-mortar-to-subfloor”
limitation. App. 1299–305. In the next office action reject-
ing the claims, the examiner submitted a drawing of the
proposed combination, which shows the structure of Doda
with the two gray segments of the base removed to create
notches similar to those in Psaila, thereby achieving a
structure akin to the structure of the claimed invention:
Case: 23-1887 Document: 57 Page: 10 Filed: 05/28/2025

-- 10 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 11
App. 799.
Subsequently, during an applicant-initiated interview
with the examiner, the applicants showed a video as a
demonstrative aid. In one image from the video, which is
reproduced below, the applicants annotated a sample em-
bodiment of the invention (referred to as the “Bunch De-
vice”), in which the edges of two adjacent tiles appear to be
flush with the inner edges of the two notches on either side
of the base of the tile clip. The applicants’ annotation of
that image described the structure as showing “Tile Edge-
to-Mortar-to-Subfloor Contact.”
Case: 23-1887 Document: 57 Page: 11 Filed: 05/28/2025

-- 11 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 12
App. 1080. The applicants also included an image of the
Doda device, which was annotated to describe the Doda de-
vice as showing “No Tile Edge-to-Mortar-to-Subfloor Con-
tact.”
App. 1081. The applicants annotated the same image to
describe the Psaila device. As in the case of the Doda de-
vice, the applicants’ annotation reads: “No Tile Edge-to-
Mortar-to-Subfloor contact.”
Case: 23-1887 Document: 57 Page: 12 Filed: 05/28/2025

-- 12 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 13
App. 1082. Following the interview, the examiner pointed
out that “the video shows the size of the notch is critical to
the success of the invention,” and therefore suggested that
the applicant “focus on the size of each notch in relation to
the size of the base.” App. 750.
In response, the applicants amended their claims to
add the limitation reciting “the combination of the first
notch and the second notch providing a majority of an area
of tile-to-mortar-to-subfloor contact for the tile leveling de-
vice within the bounds of the base.” App. 807–12. Seeking
to distinguish the prior art from their invention, the appli-
cants argued that a skilled artisan would not “have modi-
fied the base of Doda with the configuration of Psaila” by
extending the openings 129 all the way to the outer edges
of the base 116 to allow more adhesive to penetrate the
opening and extend over a greater surface area of the tiles.
App. 826. The applicants explained that “Psaila discloses
and teaches keeping any opening 129 of Doda or cut-outs
28 of Psaila away from the inside of the base 116 so the
integrity of the spacer tabs 24 is maintained.” Id. The
claims were then allowed as amended.
Case: 23-1887 Document: 57 Page: 13 Filed: 05/28/2025

-- 13 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 14
D
During the claim construction proceedings, the district
court construed the two claim limitations that are chal-
lenged on appeal. First, the court construed the term
“edge,” which appears in the phrases “edge-to-subfloor con-
tact” and “edge-to-mortar-to-subfloor contact,” to mean
“the line at which a surface of a tile terminates.” App. 8.
Second, the court construed the term “the combination of
the first notch and the second notch providing a majority of
an area of tile-to-mortar-to-subfloor contact for the tile lev-
eling device within the bounds of the base,” which appears
in the claims of the ’274 patent, but not the ’857 patent, to
mean “the notches in the base collectively span an area
that is larger than the solid portions of the base.” App. 11.
II
A
We review the district court’s claim construction and
interpretations of the intrinsic evidence de novo and any
subsidiary factual findings based on extrinsic evidence for
clear error. Apple Inc. v. Wi-LAN Inc., 25 F.4th 960, 967
(Fed. Cir. 2022).
Acufloor argues that the district court erred in constru-
ing the term “edge” to refer to a single line at which the
surface of the tile terminates, as opposed to the region in
the vicinity of the very edge of the tile.5 FORPAC and
EvenTile defend the court’s construction, arguing that it is
correct in view of the prosecution history.
As a preliminary matter, FORPAC and EvenTile argue
that Acufloor has waived its right to challenge the district
court’s construction of the term “edge,” because Acufloor
argued before the district court that “edge” did not need to
5 For simplicity, we refer in this opinion to what the
district court called the “line at which a surface of the tile
terminates” as the “very edge of the tile.”
Case: 23-1887 Document: 57 Page: 14 Filed: 05/28/2025

-- 14 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 15
be construed and should instead be given its plain and or-
dinary meaning. Although Acufloor requested that the
term “edge” be given its plain and ordinary meaning, it is
clear from the district court’s opinion that Acufloor under-
stood the plain and ordinary meaning of “edge” to refer to
a region near the very edge of the tile, which is consistent
with Acufloor’s position before us. See App. 6. Accordingly,
Acufloor has not waived its right to challenge the district
court’s claim construction. Medtronic, Inc. v. Teleflex Inno-
vations S.À.R.L., 68 F.4th 1298, 1305 (Fed. Cir. 2023).
Turning to the merits of the district court’s claim con-
struction, we agree with the district court that the term
“edge” must include the very edge of the tile or, in the dis-
trict court’s words, the line at which the surface of the tile
terminates. But we modify the court’s claim construction
slightly to include not only the very edge of the tile, but
some amount of the tile’s surface inward from the very edge
of the tile.
Claim terms are generally given the “meaning that the
term would have to a person of ordinary skill in the art in
question at the time of the invention.” Phillips v. AWH
Corp., 415 F.3d 1303, 1313 (Fed. Cir. 2005) (en banc). The
context in which the term is used in the patent’s claims and
specification is strong evidence of how a person of ordinary
skill would understand the term. See id. Here, the claims
use the term “edge” in the context of contact between two
surfaces. Specifically, the claims require contact between
either the edge and the subfloor, or the edge, mortar, and
subfloor. As a physical matter, a line, such as the one at
which the surface of the tile terminates, does not have a
surface area, so restricting the edge to only a line would
render the word “contact” meaningless. In short, for there
to be contact between the edge and either the subfloor or
mortar, the edge must have some surface area. See Merck
& Co. v. Teva Pharms. USA, Inc., 395 F.3d 1364, 1372 (Fed.
Cir. 2005) (“A claim construction that gives meaning to all
the terms of the claim is preferred over one that does not
do so.”).
Case: 23-1887 Document: 57 Page: 15 Filed: 05/28/2025

-- 15 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 16
Although we conclude that the term “edge” is not lim-
ited to the very edge of the tile, it is still necessary to de-
termine whether the “edge” must include that very edge.
Based on the prosecution history, we hold that it does: the
proper construction of “edge” must include the very edge of
the tile, even though it also includes some surface area ex-
tending from the very edge of the tile toward the center of
the tile.
During prosecution, the applicants repeatedly at-
tempted to overcome obviousness rejections by distinguish-
ing their claimed invention from the proposed prior art
combinations based on the area of the tile that would be in
contact with the mortar. Regarding the ’857 patent, the
applicants added the requirement that there be “edge-to-
subfloor contact at the first notch” to each of the claims,
App. 701–08, and they argued that the Hoffman prior art
reference did not satisfy those “edge-to-subfloor contact”
limitations, App. 714.
Specifically, the applicants argued that the grooves of
the Hoffman prior art device do not provide tile edge-to-
subfloor contact because the grooves do not “penetrate the
base portion”—i.e., the grooves do not go all the way
through the base portion. In addition, the applicants
pointed out that the very edge of the tile in the Hoffman
device rests on top of a strip of solid material and does not
directly contact the subfloor. The applicants’ annotated
version of the Hoffman device points to that strip of mate-
rial and states “Edge of tile rests here. No edge-to subfloor
contact.” App. 1052. The implication of those statements
is that the Hoffman reference does not disclose tile edge-to-
subfloor contact because the very edges of the tiles in the
Hoffman device do not directly contact the subfloor.
During the prosecution of the ’274 patent, the appli-
cants added limitations requiring “edge-to-mortar-to-sub-
floor contact” to what became claims 1–7 of the ’344
application. App. 1299–305. With that amendment, the
applicants distinguished their invention from the prior art
Case: 23-1887 Document: 57 Page: 16 Filed: 05/28/2025

-- 16 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 17
combination, which would “push out” the mortar—i.e., it
would push the mortar away from the very edge of the tile,
such that the combination would not provide the claimed
tile edge-to-mortar-to-subfloor contact. App. 1312. In con-
trast, the applicants explained that the “correct way” to use
a leveling device is to insert it so that “it encourages mortar
to reach as close to the edge as possible.” App. 1085. Those
statements indicate that the applicants viewed maintain-
ing mortar up to the very edge of the tile to be an important
feature of their claimed invention.
Finally, the images and statements from the appli-
cants’ demonstrative aids support this interpretation of
“edge.” They refer to the “Bunch device” with openings that
are flush with the very edges of the adjacent tiles as having
tile edge-to-subfloor contact, and they refer to devices with
openings that do not allow contact between the very edges
of the tiles and the subfloor as not having tile edge-to-sub-
floor contact. Compare App. 1080 with App. 1081 and App.
1082.
In short, the applicants repeatedly distinguished their
invention from the prior art on the ground that the prior
art devices do not permit the tile to be in contact with the
mortar all the way to the very edge of the tile, whereas the
claimed invention permits the mortar to extend to that
point. In view of those statements, we agree with the dis-
trict court that the inventors contemplated that the edge
would include the very edge of the tile. Therefore, we con-
strue edge to mean “the area around and including the very
edge of the tile.”6
6 We recognize that our construction of the “edge”
limitation differs only slightly from the district court’s con-
struction, and that the difference may have little or no
practical impact. However, because we are remanding this
case based on the second disputed claim construction issue,
Case: 23-1887 Document: 57 Page: 17 Filed: 05/28/2025

-- 17 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 18
In support of its interpretation of the term “edge,”
Acufloor argues that the district court improperly relied on
the prosecution history because Acufloor’s statements did
not constitute a clear and unmistakable disclaimer of claim
scope. As we have consistently held, however, “any expla-
nation, elaboration, or qualification presented by the in-
ventor during patent examination is relevant, for the role
of claim construction is to ‘capture the scope of the actual
invention’ that is disclosed, described, and patented.” Iri-
descent Networks, Inc. v. AT&T Mobility, LLC, 933 F.3d
1345, 1352–53 (Fed. Cir. 2019) (quoting Fenner Invs., Ltd.
v. Cellco P’ship, 778 F.3d 1320, 1323 (Fed. Cir. 2015)). The
prosecution history “can often inform the meaning of the
claim language by demonstrating how the inventor under-
stood the invention and whether the inventor limited the
invention in the course of prosecution, making the claim
scope narrower than it would otherwise be.” Phillips, 415
F.3d at 1317. Here, we do not construe the term “edge”
based on a finding of disclaimer. Rather, we look to the
prosecution history to inform us of how a person of ordinary
skill in the art would understand the term “edge” as used
in the asserted patents.
Acufloor places great weight on the argument that the
district court’s construction improperly excludes an embod-
iment of the invention that is depicted in Figure 11A of the
patents. We disagree. At page 44 of its brief, Acufloor has
annotated Figure 11A by incorporating a dotted line ex-
tending along the base of the clip between the two spacing
pads. Acufloor argues that the diagram shows that if a tile
were installed over the base and pressed against the spac-
ing pads, the very edge of the tile would lie on top of a
and because this appeal was taken from a stipulated judg-
ment, we deem it appropriate to allow the district court in
the first instance to assess the effect of the modified con-
struction of the “edge” term as applied to the facts of this
case.
Case: 23-1887 Document: 57 Page: 18 Filed: 05/28/2025

-- 18 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 19
portion of the base, and thus not be in direct contact with
the subfloor.
The problem with that argument is that it is based en-
tirely on an interpretation of the perceived dimensions of
the drawing in Figure 11A, and this court has held that
“arguments based on drawings not explicitly made to scale
in issued patents are unavailing.” Nystrom v. TREX Co.,
424 F.3d 1136, 1149 (Fed. Cir. 2005); see also Regents of
Univ. of Cal. v. Satco Prods., Inc., No. 2023-1356, 2024 WL
4972639, at *3 (Fed. Cir. Dec. 4, 2024) (“[P]atent drawings
do not define the precise proportions of the elements and
may not be relied on to show particular sizes if the specifi-
cation is completely silent on the issue.”); Krippelz v. Ford
Motor Co., 667 F.3d 1261, 1268 (Fed. Cir. 2012) (“This court
has repeatedly cautioned against overreliance on drawings
that are neither expressly to scale nor linked to quantita-
tive values in the specification.”); In re Wright, 569 F.2d
1124, 1127 (CCPA 1977) (“Absent any written description
in the specification of quantitative values, arguments
based on measurement of a drawing are of little value.”).
Here, the specification does not suggest that its figures are
drawn to scale or are more than rough depictions of the in-
vention.
The more reliable guide to the relationship between
the tile edges and the notches in the claimed tile clip is
found in the prosecution history summarized above, which
makes clear that in the claimed clips, unlike in the prior
art devices, the opening between the subfloor and tile ex-
tends to the very edge of the tile. Although Acufloor cites
expert testimony to support its interpretation of Figure
11A, extrinsic evidence may not contradict intrinsic evi-
dence. See Phillips, 415 F.3d at 1318.7 And there is
7 In any event, the expert declaration on which
Acufloor relies is addressed primarily to rebutting the de-
fendants’ theory that the “edge” of the tile is the line at
Case: 23-1887 Document: 57 Page: 19 Filed: 05/28/2025

-- 19 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 20
nothing in the intrinsic evidence to support Acufloor’s con-
tention that the very edge of the tile need not be in direct
contact with the subfloor. Our construction therefore does
not read a preferred embodiment out of the patent, as
Acufloor contends.8
which the tile terminates. See App. 644–45 (¶¶ 74–75).
The expert’s separate argument that the term “edge” does
not include the very edge of the tile consists only of a re-
statement of Acufloor’s argument based on Figure 11A
from the common specification and a questionable interpre-
tation of one of the images of the “Bunch device” presented
to the examiner during the prosecution. See id. at 646–48
(¶¶ 78–79).
8 The dissent argues for a construction of the term
“edge” under which the mortar-to-subfloor contact could
end at some undefined distance from the very edge of the
tile. The dissent acknowledges that it “may well be” that
its construction would render the claims at issue inva-
lid. We agree that the dissent’s construction would raise
serious questions about the validity of the claims, as the
construction leaves undefined how much distance there
could be between the very edge of the tile and the portion
of the tile having mortar-to-subfloor contact while still sat-
isfying the limitation requiring “tile edge-to-mortar-to-sub-
floor contact.” But the potential indefiniteness problem is
more than just a happenstance consequence of the dissent’s
construction; it is a factor that cuts against adopting that
construction in appropriate cases. As we have explained,
when there is doubt as to the proper construction of a claim
term, the construction that preserves the validity of the
claim should be adopted. See Phillips, 415 F.3d at 1327;
Liebel-Flarsheim Co. v. Medrad, Inc., 358 F.3d 898, 911
(Fed. Cir. 2004).
Case: 23-1887 Document: 57 Page: 20 Filed: 05/28/2025

-- 20 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 21
B
With respect to the construction of “majority of an
area” limitation in the ’274 patent, the parties dispute
whether that phrase refers to a majority of the area of con-
tact between the tile and the subfloor, or a majority of the
area of the base. The district court concluded that the op-
erative area is the area of the base. We disagree.
The plain language of the “majority of an area” limita-
tion dictates its proper construction. The limitation states
in full: “the combination of the first notch and the second
notch providing a majority of an area of tile-to-mortar-to-
subfloor contact for the leveling device within the bounds
of the base.” Because the term “area” in the limitation ex-
pressly refers to the area of tile-to-mortar-to-subfloor con-
tact and not to the area of the base, the plain terms of the
limitation support Acufloor’s construction. Nothing in the
limitation relates the area of the notches to the area of the
solid portions of the base.
It is true that the “majority of an area” limitation was
added to the claims of the ’274 patent following the exam-
iner’s suggestion that the applicants “focus on the size of
each notch in relation to the size of the base” and “amend[]
the claim language to better define the size of the notch [to]
further distinguish from the prior art of record.” App. 750.
If the applicants had used the language suggested by the
examiner, the construction adopted by the district court
would likely have been correct. But the applicants did not
adopt that language; instead, in their March 25, 2020, re-
sponse to the examiner’s February 27, 2020, communica-
tion, they adopted language clearly pointing in a different
direction, App. 805–29, and the examiner allowed the
claims as so amended, id at 831–32.
The district court relied on statements from earlier in
the prosecution history to support its conclusion that the
amendment “distinguishes Acufloor’s device from the prior
art because the Acufloor design allows a relatively large
area of direct contact between subfloor, mortar, and tile.”
Case: 23-1887 Document: 57 Page: 21 Filed: 05/28/2025

-- 21 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 22
See App. 10. In support of that conclusion, the district
court quoted the applicants’ argument that their design al-
lowed “more adhesive to penetrate the opening and extend
over a greater surface area of the tiles” than the prior art.
Id. In making that argument, however, the applicants
were explaining that a skilled artisan would not extend the
opening 129 in Doda toward the base; they were not argu-
ing that their device shrinks the size of the base, thereby
generally permitting more contact. App. 826. Because the
applicants’ argument was specific as to how the opening of
Doda would or would not be modified, we understand the
applicants to have been distinguishing their device from
the prior art based on the area of contact permitted by the
notch as compared to the area of contact permitted by other
openings—i.e., based on the fact that the claimed notches
provide the majority of the area of contact. That under-
standing supports our conclusion that the district court
erred in relating majority to the area of the base as opposed
to relating it to area of contact.
The district court stated that the applicants “gave no
indication [they] contemplated other openings when add-
ing the ‘majority of an area’ phrase.” App. 10. As noted
above, however, the applicants explicitly argued that the
opening 129 in Doda would not be extended. They similarly
argued that the cut-outs in Psaila, i.e., the round openings
shown in that reference, would not be extended. App. 826
(“Psaila does not disclose or teach extending . . . cut-outs 28
of Psaila . . . .”). The references in the prosecution history
to the openings in Doda and Psaila suggest that the appli-
cants’ amendment was made with other openings in mind.
The defendants similarly argue that the “majority of
the area” limitation cannot be directed to a comparison be-
tween the notch and other openings, because there are no
other openings recited in claims. But the claims use the
transition word “comprising” and are therefore presump-
tively open. Genentech, Inc. v. Chiron Corp., 112 F.3d 495,
501 (Fed. Cir. 1997) (“‘Comprising’ is a term of art used in
claim language which means that the named elements are
Case: 23-1887 Document: 57 Page: 22 Filed: 05/28/2025

-- 22 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 23
essential, but other elements may be added and still form
a construct within the scope of the claim.”). Accordingly,
the claims, as amended, permit the claimed device to have
other openings, such as those in the Psaila device, so long
as the notches provide the majority of the open area for the
tile, mortar, and subfloor contact. Based on the claim lan-
guage and the prosecution history, we therefore construe
the “majority of an area” term to mean “the combination of
the first notch and the second notch providing the majority
of the area of the tile-to-mortar-to-subfloor contact that ex-
ists within the bounds of the base.”
III
For the foregoing reasons, we modify the district
court’s construction of the term “edge” as used in the claims
of the ’274 patent and the ’857 patent. And we disagree
with the district court’s construction of the term “the com-
bination of the first notch and the second notch providing
a majority of an area of tile-to-mortar-to-subfloor contact
for the leveling device within the bounds of the base” as
used in the claims of the ’274 patent. We therefore vacate
the stipulated judgment of infringement and remand for
further proceedings consistent with this opinion.
No costs.
VACATED AND REMANDED
Case: 23-1887 Document: 57 Page: 23 Filed: 05/28/2025

-- 23 of 30 --

N OTE : This disposition is nonprecedential.
United States Court of Appeals
for the Federal Circuit
______________________
ACUFLOOR, LLC,
Plaintiff-Appellant
v.
EVENTILE, INC., FORPAC, LLC,
Defendants-Appellees
______________________
2023-1887
______________________
Appeal from the United States District Court for the
Middle District of Florida in No. 2:21-cv-00802-SPC-KCD,
Judge Sheri Polster Chappell.
______________________
STARK, Circuit Judge, concurring-in-part and dissenting-
in-part.
I agree with my colleagues that the district court
erred in its construction of the “majority of an area” term
in the ’274 patent. The correct construction is “the combi-
nation of the first notch and the second notch providing the
majority of the area of the tile-to-mortar-to-subfloor con-
tact that exists within the bounds of the base.” Maj. at 23.
I further agree that we must vacate the judgment of non-
infringement and remand for further proceedings. There-
fore, I join all parts of the majority opinion other than
Part II.A.
Case: 23-1887 Document: 57 Page: 24 Filed: 05/28/2025

-- 24 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 2
I disagree, however, with the majority’s determina-
tion that the correct construction of “‘edge’ must include the
very edge of the tile or, in the district court’s words, the line
at which the surface of the tile terminates.” Id. at 15. In
my view, the proper construction of “edge” is broader: it al-
lows contact at “the very edge of the tile” but only requires
that such contact occur either at the very edge or in the
area near that very edge. Thus, in the remand proceedings
we are ordering, I would instruct the district court to apply
Acufloor’s construction of “edge,” which “includes an area
or region where two surfaces of a tile meet.” Open. Br. at
59; see also Appx584 (Acufloor arguing in claim construc-
tion briefing the “patents use the term ‘edge’ to refer to a
region or area, not a single line”).1
I
The majority does not suggest that the claim lan-
guage itself clarifies for the person of ordinary skill in the
art whether Acufloor’s or the court’s construction is correct.
My colleagues also appear to recognize that the specifica-
tion supports Acufloor’s position. This is because the Fig-
ure 11A embodiment, which the specification describes as
an “implementation” in which “each tile has edge-to-sub-
floor contact due to the notches,” ’274 patent at 6:18-19, is
within the scope of the claims under Acufloor’s construction
but is excluded under the majority’s. Maj. at 19-20. Be-
cause the specification tells us the Figure 11A embodiment
meets the claim limitation, even though one can see from
1 It may well be that this construction renders
Acufloor’s claims invalid. See generally Nautilus, Inc. v.
Biosig Instruments, Inc., 572 U.S. 898, 909 (2014) (“[A] pa-
tent must be precise enough to afford clear notice of what
is claimed, thereby apprising the public of what is still open
to them.”). I would leave it to the district court on remand
to allow the parties to litigate invalidity arguments, which
are not before us on appeal.
Case: 23-1887 Document: 57 Page: 25 Filed: 05/28/2025

-- 25 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 3
the figure that this embodiment would not allow mortar to
reach “the very edge” of the tile, a construction excluding
this embodiment is likely incorrect.2 See, e.g., Oatey Co. v.
IPS Corp., 514 F.3d 1271, 1277 (Fed. Cir. 2008) (“[W]here
claims can reasonably [be] interpreted to include a specific
embodiment, it is incorrect to construe the claims to ex-
clude that embodiment, absent probative evidence [to] the
contrary.”). For this reason, I view the specification as
providing strong support for Acufloor’s construction.
The majority’s analysis is devoted almost entirely to
the prosecution history. While there are indications in the
prosecution history that the patent applicant may have in-
tended to narrow claim scope in the manner the majority
has determined, see Maj. at 16-17, I find the prosecution
history too ambiguous to support the majority’s conclusion.
II
Patent prosecution involves an applicant in an “on-
going negotiation” with the Patent Office, ultimately re-
sulting in allowable claims if its subject matter is
determined to be patentable. Phillips v. AWH Corp.,
415 F.3d 1303, 1317 (Fed. Cir. 2005) (en banc). The record
developed in reaching that endpoint “often lacks” clarity.
Id. Even so, a patent’s prosecution history can “inform the
2 The majority denigrates reliance on Figure 11A be-
cause it is not drawn to scale. Maj. at 19. I see nothing
wrong with Acufloor pointing to the figure to help the court
interpret a claimed feature that the specification unequiv-
ocally states is shown in that very figure. See generally
Motionless Keyboard Co. v. Microsoft Corp., 486 F.3d 1376,
1380 (Fed. Cir. 2007) (approving use of figure to construe
disputed term in manner consistent with depiction in that
figure). Acufloor is not trying to use the figure to limit
claim scope, as the cases the majority cites caution against.
See Maj. at 19.
Case: 23-1887 Document: 57 Page: 26 Filed: 05/28/2025

-- 26 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 4
meaning of the claim language by demonstrating [i] how
the inventor understood the invention and [ii] whether the
inventor limited the invention in the course of prosecution,
making the claim scope narrower than it would otherwise
be.” Id. (internal numbering added); see also AstraZeneca
AB v. Mylan Pharms. Inc., 19 F.4th 1325, 1335 (Fed. Cir.
2021) (“[A]ny explanation, elaboration, or qualification pre-
sented by the inventor during patent examination is rele-
vant, for the role of claim construction is to capture the
scope of the actual invention that is disclosed, described,
and patented.”) (internal quotation marks omitted). Here,
while the prosecution history informs us as to how the in-
ventor understood his invention, I do not read that history
as showing the inventor “limited the invention” or made
“the claim scope narrower than it would otherwise be.”3
Phillips, 415 F.3d at 1317.
The majority tells us that the proper construction of
“edge” must include “the very edge” because, first, the “ap-
plicant[] added the [edge] requirement” to overcome the
Hoffman reference. Maj. at 16 (citing Appx701-08,
Appx714). Specifically, the majority points to the appli-
cant’s arguments “that the grooves of the Hoffman prior art
device do not provide tile edge-to-subfloor contact because
3 The panel is unanimous in concluding that the prose-
cution history does not support a “finding of disclaimer.”
Maj. at 18. “For a statement during prosecution to qualify
as a disavowal of claim scope, it must be so clear as to show
reasonable clarity and deliberateness, and so unmistaka-
ble as to be unambiguous evidence of disclaimer.” Genuine
Enabling Tech. LLC v. Nintendo Co., 29 F.4th 1365, 1374
(Fed. Cir. 2022) (internal quotation marks and citation
omitted). My colleagues and I agree that the prosecution
history here is devoid of such unmistakable, unambiguous
evidence.
Case: 23-1887 Document: 57 Page: 27 Filed: 05/28/2025

-- 27 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 5
the grooves do not penetrate the base portion” and “the
very edge of the tile in the Hoffman device rests on top of a
strip of solid material and does not directly contact the sub-
floor.” Maj. at 16 (internal quotation marks omitted). The
majority concludes that “[t]he implication of those state-
ments is that the Hoffman reference does not disclose tile
edge-to-subfloor contact because the very edges of the tiles
in the Hoffman device do not directly contact the subfloor.”
Id. (emphasis added).
I do not believe this mere “implication” is sufficient to
overcome the clear indication in the specification, espe-
cially from Figure 11A and the discussion of it, that the
“edge” limitation does not require mortar to reach “the very
edge” of the tile. There are other plausible readings of the
applicant’s statements. One argued by Acufloor is that the
applicant was distinguishing Hoffman based on Hoffman’s
grooves (element 1618 as shown in Figure 16 reproduced in
the majority opinion at 9) being unable to provide edge-to-
mortar-to-subfloor contact because they do not provide
mortar-to-subfloor contact; the grooves instead provide
edge-to-groove mortar contact. See Open. Br. at 56-58 (cit-
ing Appx714).
The majority next cites to the applicant’s amendment
adding the “edge-to-mortar-to-subfloor” limitation to
claims 1-7 of the ’274 patent, accompanied by a statement
by which the “applicant[] distinguished the[] invention
from the prior art combination, which would ‘push out’ the
mortar . . . away from the very edge of the tile.” Maj. at 16-
17 (quoting Appx1312). But this statement, too, is ambig-
uous. It provides no clarity as to whether the applicant
understood and intended “edge” to be limited to the “line at
the very edge” or to more broadly also include the area near
(and including) that line.
Finally, the majority finds support for its conclusion
that the inventor narrowed claim scope during prosecution
in statements the inventor made in a video demonstrative
Case: 23-1887 Document: 57 Page: 28 Filed: 05/28/2025

-- 28 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 6
he submitted to the examiner. Maj. at 17-20 (citing
Appx1080-82).4 The majority sees the video as showing,
and thus requiring in the claims, “openings that are flush
with the very edges of the adjacent tiles as having tile edge-
to-subfloor contact . . . .” Maj. at 17. I see the video differ-
ently. I think it simply shows a person of skill in the art
touting the benefits of getting mortar to an area as close to
the very edge as possible. Appx1077-78 (“There is a tre-
mendous advantage to notches, but only if they are in-
serted the correct way. The correct way would be to insert
it as it encourages mortar to reach as close to the edge as
possible.”); see also Appx1073 (“[W]e are therefore trying to
protect the other vulnerable portion of the tile installation,
namely the edge.”).
To the extent the video is pertinent to the claim con-
struction dispute, it favors Acufloor’s broader construction,
because the embodiment used in the video (the “Bunch De-
vice”) shows no edge-to-mortar-to-subfloor contact at the
very edge of the tile. Appx1086 (showing that mortar does
not reach very edge of clear plexiglass tiles); Appx1087
(showing, from perspective of the underside of tile, how
Bunch Device overlaps with the very edge of tile, prevent-
ing mortar contact at that line). If the majority’s construc-
tion is correct, the devices the applicant chose to use to
4 Screenshots from the video appear in several places
in the record, including Appx1073-94. The entire video was
provided to the examiner through a Youtube link,
Appx.750, and remains available there. See Comparison of
Devices for Leveling and Aligning Tiles, Y OUTUBE .COM ,
https://www.youtube.com/watch?v=qQHE4mq7SVg. Be-
cause the video demonstrative was submitted to and con-
sidered by the examiner, it is intrinsic evidence. I agree
with the district court that there is no need in this case to
consider the parties’ extrinsic evidence.
Case: 23-1887 Document: 57 Page: 29 Filed: 05/28/2025

-- 29 of 30 --

ACUFLOOR, LLC v. EVENTILE, INC. 7
show the examiner what his invention covers would not
themselves be within the scope of the issued claims. The
video, as well as the rest of the prosecution history, is too
ambiguous to justify this implausible result.
III
In my view, the prosecution history contains little that
helps us resolve the dispute over the proper construction of
the “edge” term. It mostly reveals that the applicant un-
derstood his invention as allowing mortar to get as close as
possible to the very edge of the tile, and that this is benefi-
cial for reducing the vulnerability of tile at its edge, where
it may break.
I conclude, then, that the applicant did not narrow the
scope of his claims during prosecution, either by argument
or by amendment. Consequently, the embodiment depicted
in Figure 11A, which does not require edge-to-mortar-to-
subfloor contact at the very edge, remained within the
scope of the issued claims. The majority’s construction,
which excludes that embodiment by narrowly limiting the
claims to only those embodiments in which such contact oc-
curs at the very edge of the tile, is, therefore, incorrect.
I respectfully dissent.
Case: 23-1887 Document: 57 Page: 30 Filed: 05/28/2025

-- 30 of 30 --