Nike Inc. and Skechers USA Inc. have been locked in a yearslong patent battle over sports shoe designs, highlighting a tricky question in patent law: How do you show that a contested design has already been done before?
Nike sued Skechers in 2016, claiming that the latter’s Burst and Flex shoes copied its patented designs in the Nike Free 3.0, Nike Free 4.0 and Nike Flyknit Air Max shoe models released a few years earlier. The patents at issue cover diagonal and V-shaped threaded designs on shoe uppers and three-dimensional block-shaped designs on the soles.
But after nearly four years and more than a dozen frustrated challenges to the U.S. Patent and Trademark Office, Skechers is still questioning if Nike’s patents for the designs are valid, according to filings in California federal court.
In its own filing on Monday, Nike slammed the Skechers shoes as reflecting an approach of “copying its competitors’ shoes and making ‘Skecherized’ versions of them.” Skechers argued the Nike designs in question have long been in the public domain, and, therefore, fair game for competitors.
“Nike cannot escape the fact that its claimed designs are mere reiterations of design elements that Nike placed in the public domain years before Nike filed the patents-in-suit,” Skechers argued in the filing.
Successfully disputing a patent takes showing that the design it covers is obvious, which usually means pointing to earlier shoe designs with the same “visual impression” — so-called “primary references,” or earlier instances of the design that bear roughly the same overall look.
To that end, Skechers has pointed to a number of what it argues are similar previous shoe designs, or “prior art” in intellectual property law jargon. Examples it points to include the Nike Lunar 1 shoe with a V-shaped design radiating from the shoelaces, and the Nike Free Walk shoes with similar sole designs.
“Skechers has presented detailed expert opinions establishing that each of the challenged prior art references are primary references,” Skechers argued in its filing. “Thus, while Nike may disagree with Skechers’ experts, these are disputed issues of material fact for the jury to decide.”
For its part, Nike has pointed out that the Patent Trial and Appeal Board, the administrative section of the U.S. PTO that hears disputes and appeals, has denied the 15 petitions by Skechers to find the Nike patents invalid.
The patent controversy between the footwear rivals is also playing out in other cases in the same federal court, one of which previously prompted Skechers to issue a letter accusing Nike of bullying.
“Skechers respects the intellectual property rights of others but our much larger competitor continues to use its vast resources to stifle competition in the courtroom rather than compete in the marketplace,” Skechers wrote in the letter.
Nike referenced the letter in another suit it filed just last month over the Skech-Air Jumpin’ Dots and Skech-Air Mega shoes, in which it once again accused Skechers of frequently imitating its designs.
“Nike has a strong history of innovation and leadership in footwear design and development,” a Nike representative said Tuesday. “We innovate to help athletes reach their potential and we vigorously defend and enforce the intellectual property that protects those innovations.”
A representative for Skechers could not be reached for comment.