IP Law Daily, PATENT—Fed. Cir.: Noninfringement ruling in tile spacer patent dispute between construction tool companies vacated on appeal, (May 28, 2025)

By Saurabh Kashyap, B.A., LL.B., LL.M.

The district court improperly narrowed “edge” and “majority of area” limitations in asserted claims.

In a non-precedential disposition, the U.S. Court of Appeals for the Federal Circuit vacated and remanded a Florida district court’s noninfringement ruling in an infringement lawsuit between competing construction tool companies. The appellate court found that the district court had improperly construed the claim term “edge” too narrowly and misinterpreted the phrase “majority of an area of tile-to-mortar-to-subfloor contact,” adopting claim constructions that were inconsistent with the intrinsic evidence and the functional scope of the asserted patents. Circuit Judge Leonard P. Stark dissented in part, disagreeing with the majority’s interpretation of the “edge” limitation (Acufloor, LLC v. Eventile, Inc., No. 23-1887 (Fed. Cir. May 28, 2025)).

Background. The plaintiff/appellant, Acufloor, LLC, is a construction tool company specializing in tile installation systems, including plastic clip-and-wedge devices that aid in aligning tiles during installation. The defendants/appellees, EvenTile, Inc. and FORPAC, LLC, are Florida-based businesses engaged in the manufacture and sale of tile spacing and leveling products. The parties are direct competitors in the tile-laying accessories market.

In this lawsuit, Acufloor asserted its U.S. Patent Nos. 10,704,274 (the '274 patent) and 10,513,857 (the '857 patent), which share a common specification and relate to tile spacer systems that allow adjacent tiles to sit evenly on a subfloor during mortar setting. The patented systems include frangible clips, vertical wedges, and base notches that enable mortar to reach the tile edges, allowing for physical contact between the tile and the subfloor. The asserted claims emphasize direct contact at the tile's edge and functional openings that permit a majority of tile-to-mortar-to-subfloor bonding area within the base.

Acufloor filed this lawsuit in 2021, alleging that EvenTile and FORPAC's wedge-style leveling systems infringed several claims of the '274 and '857 patents. During claim construction, the district court adopted narrow constructions of two critical limitations: it defined "edge" as "the line at which a surface of a tile terminates" and interpreted the phrase "majority of an area of tile-to-mortar-to-subfloor contact" to require that the notches in the base occupy a greater physical area than the solid parts of the clip base. Based on those constructions, the parties stipulated to noninfringement, and a final judgment was entered in the defendant's favor. Acufloor appealed.

Claim construction—“edge” limitation. On appeal, the Federal Circuit rejected the district court's narrow definition of "edge." While acknowledging that the edge includes the terminating line of a tile, the court explained that a literal line has no thickness and, therefore, cannot itself be in contact with other elements. Citing Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (en banc), the court emphasized that terms must be read in context and that claim language must not be so narrowly construed as to exclude embodiments shown in the specification.

The Federal Circuit also examined the prosecution history. During examination, Acufloor had repeatedly distinguished its invention from prior art by showing that its clip designs allowed mortar to reach the tile’s actual edge. These arguments, including annotated diagrams and video demonstrations, led the USPTO to allow the claims. The court found that Acufloor clearly relied on "edge," referring to the outer perimeter region of the tile, not just a conceptual line. The court concluded that "edge" encompasses both the physical boundary and the adjacent contact region.

Claim construction—“majority of an area” limitation. The Federal Circuit also disagreed with the district court’s interpretation of a second limitation found in claim 1 of the ’274 patent. That limitation required that “the combination of the first notch and the second notch provid[es] a majority of an area of tile-to-mortar-to-subfloor contact … within the bounds of the base.” The district court read this to mean that the notches must collectively be larger than the remaining solid areas of the clip base.

The appellate court found this construction unsupported. The phrase “majority of an area of tile-to-mortar-to-subfloor contact” referred to the functional contact surface, not to a geometric area of plastic or open space. The court noted that the claim used the word “comprising,” which allows for other structures or openings to be present, and that the language described the effect of the notches—namely, to enable a large contact area with mortar and subfloor—rather than requiring the notches to occupy a mathematically greater area than the base’s solid sections. The Federal Circuit cited Merck & Co. v. Teva Pharms. USA, Inc., 395 F.3d 1364 (Fed. Cir. 2005) to emphasize that terms should be interpreted based on their function and role in the invention rather than arbitrary numerical comparisons.

Furthermore, the Federal Circuit also emphasized the significance of open-ended claim language in assessing the scope of the asserted limitations. The court noted that the term “comprising,” used in the phrase “a majority of an area of tile-to-mortar-to-subfloor contact … within the bounds of the base,” signaled that the claim permitted additional structures or elements beyond the specifically recited notches.

Conclusion. Because the final judgment of noninfringement was stipulated by the parties based on the district court’s claim constructions, the Federal Circuit vacated that judgment. It remanded the case for further proceedings under the corrected interpretations. The court stated that it expressed no view on the ultimate infringement question, which would need to be reassessed in light of the broader claim scope.

Partial dissent. Circuit Judge Leonard P. Stark dissented in part. While he agreed with the majority’s interpretation of the “majority of an area” limitation, he disagreed with its construction of “edge.” Judge Stark maintained that the intrinsic record was ambiguous and that the prosecution history did not clearly define “edge” as extending beyond the tile’s boundary line. He argued that the majority’s construction risked excluding disclosed embodiments—particularly the one shown in Figure 11A, where mortar contact may occur short of the tile’s outermost point.

The Case is No. 23-1887.

Judge: Bryson, W.

Attorneys: John Russell Emerson (Haynes and Boone, LLP) for Acufloor, LLC. Robert Manhas (Orrick, Herrington & Sutcliffe LLP) for Eventile, Inc.

Companies: Acufloor, LLC; Eventile, Inc.

Cases: Patent FedCirNews