Controlling the meaning of claim terms is essential to drafting strong patents, while pre-empting common claim construction issues is crucial to the scope of patents when it comes to infringement. In Socket Solutions, LLC v. Import Global, LLC, No. 2025-1121 (Fed. Cir. Aug. 4, 2026), the Federal Circuit vacated the district court’s grant of a preliminary injunction due to multiple errors in claim construction. The case shows how important it is to effectively align the language of the claim with the description of the term in the specification.
Key Takeaways
- Requirements not supported by the specification will not be used by the courts to properly construct the meaning of claim terms;
- Claim terms that do not use the word “means” create a rebuttable presumption that they are not means-plus-function terms; and
- In order to rebut the presumption, the specification must fail to recite “a sufficiently definite structure” for the claim term.
Socket Solutions, LLC owns U.S. Patent No. 9,509,080 directed to an electrical wall outlet cover that hides the outlet’s contact openings. Socket Solutions brought suit against Import Global, LLC alleging that their “Neat Socket” product infringed claim 19 of the ‘080 patent and moved for a preliminary injunction. The district court granted the preliminary injunction, which Import Global appealed. Import Global’s appeal alleged that the district court’s grant of the preliminary injunction was “based on an incorrect construction of the terms ‘backplate’ and pin.’” Our analysis focuses on the Federal Circuit’s discussion of the construction of these terms.
First, regarding the claim term “backplate,” the district court interpreted this to mean “the component of the cover, opposing the frontplate, that includes at least one set of electrical prongs.” In their appeal, Import Global argued that the term meant the “portion of the apparatus closest to the wall outlet when the apparatus is plugged into the wall outlet.” The Federal Circuit rejected both of these interpretations of “backplate” because they “impose spatial reference requirements that the specification does not require.”
The Federal Circuit made it clear that there must be a nexus between the claim language and the specification to support the interpretation of a claim term. Specifically, the Federal Circuit cited Phillips v. AWH Corp., which states “[t]he construction that stays true to the claim language and most naturally aligns with the patent’s description of the invention will be, in the end, the correct construction.” Phillips v. AWH Corp., 415 F.3d 1303, 1316 (Fed. Cir. 2005) (en banc). In search of the specification’s description of “backplate,” the Federal Circuit found that a construction that focuses on the thickness of the “backplate” was most appropriate because “the written description explicitly defines ‘cover’ thickness in relation to the ‘backplate.’”
Second, regarding the claim term “pin,” the district court interpreted this term to be a means-plus-function limitation. The Federal Circuit rejects the district court’s interpretation because “pin” does not include the word “means” and the specification recites a sufficient structure that is reasonably well understood in the art. The Federal Circuit sets up a rebuttable presumption against interpreting a claim term as a “means-plus-function” limitation where the claim term does not use the word “means.” As “pin” does not include the word “means,” there is a rebuttable presumption against “pin” being construed as a means-plus-function limitation. However, the presumption may be rebutted “if the challenger demonstrates that the claim term fails to recite sufficiently definite structure or else recites function without reciting sufficient structure for performing that function.” Williamson v. Citrix Online, LLC, 792 F.3d 1339, 1348 (Fed. Cir. 2015). The Federal Circuit pointed to the specification of the ‘080 patent, which defines “pin” as a structure, something the parties do not dispute. Accordingly, the Federal Circuit concludes that the presumption against “pin” being interpreted as a means-plus-function term has not been overcome. This again highlights the importance of the written description’s role in claim construction.
The Federal Circuit’s decision in Socket Solutions emphasizes the importance of aligning the written description with the claim language. Any gap between the specification and claim terms leaves open the possibility for courts to interpret claim limitations in unintended ways. This can weaken the scope of protection for patents and leave patent holders vulnerable to infringement. It is thus important to remember to make sure claim terms align with their description in the specification. Even when terms are not explicitly defined in the specification, it is important to ensure that their intended meaning does not rely on requirements that are not present in the description. If you have any questions, contact the authors of this alert.