Nike v. New Balance — Court Defines the Boundaries of Flat-Knit Footwear Patents

Background

Nike sued New Balance for allegedly infringing patents covering aspects of Nike’s Flyknit footwear technology. The asserted patents describe shoe uppers made through knitting processes, including structures designed to be knit into shape rather than cut from a larger sheet of textile. After inter partes review proceedings and the dismissal of claims involving one patent, the district court addressed four disputed claim terms that will shape the remaining infringement and validity disputes.

The parties disagreed over whether an “article of footwear” could include socks or hosiery, what qualifies as a “flat knit textile element,” which part of an upper must define the heel region, and whether an “ankle part” must extend above the wearer’s ankle bones. Claim construction determines the legal meaning of patent language before the court compares the claims with the accused New Balance products.

The Court’s Holding

The court adopted constructions that largely track the claim language and the patents’ descriptions of completed footwear. It held that an “article of footwear” must include both an upper and a sole structure, excluding hosiery, stockings, and socks. The surrounding claims and specification consistently described footwear as having those two components, and the court rejected Nike’s broader proposal that could have swept in foot coverings without soles.

For “a flat knit textile element,” the court required an element produced with its finished edges through flat knitting rather than one cut from a larger textile web. The resulting element therefore has only flat-knit edges. That construction reflects the patents’ distinction between knit-to-shape components and textile structures that must later be cut out of surrounding material.

The court construed the heel-related limitation to mean that the non-textile element is attached to a portion of the flat-knit textile element, and that textile portion defines the heel region. It declined New Balance’s reading under which the non-textile reinforcement itself would define the heel. Finally, the phrase “ankle part for covering at least a portion of an ankle of the wearer” received its ordinary and customary meaning. The specification’s example of a structure extending above the medial and lateral ankle bones described some embodiments, not a limitation that belonged in every claim.

Key Takeaways

• The asserted footwear claims require a shoe-like structure with both an upper and a sole; socks and hosiery are outside the construed term.
• “Flat knit” edges must be formed in the knitting process, reinforcing the patents’ focus on knit-to-shape manufacturing rather than cutting parts from a textile web.
• A specification’s preferred or illustrated embodiment does not automatically narrow broader claim language.
• Courts construe claims from the patent record, not simply to include or exclude the accused products.

Why It Matters

The order establishes the vocabulary that will govern Nike’s infringement case against New Balance. The construction of “flat knit textile element” may be especially important because it ties the claims to a manufacturing distinction—forming finished edges during knitting—that can be tested against how the accused shoe uppers are actually made.

More broadly, the ruling is a practical illustration of the balance in claim construction. Context can limit a general phrase such as “article of footwear,” but courts should not import a feature from an example in the specification when the claim itself is broader. Those choices can determine whether a patent reaches competing products long before a jury considers infringement.