A federal judge ruled Chadder's restaurant in American Fork can stay open as long as it doesn't sell, advertise or make any orders using In-N-Out Burger's trademarked burger names.

If customers ask for menu items using the names, "Animal," "Protein," "3x3" "4x4" or "Double Double," Chadder's employees must say the restaurant doesn't offer those and refer them to Chadder's menu, according to a court order issued Friday by U.S. District Judge Ted Stewart.

The ruling comes less than a month after In-N-Out sued Chadder's claiming the small American Fork restaurant was ripping off the Irvine, Calif.-based burger chain's concept from its signature red-and-white color scheme to the way food is packaged.

Stewart denied In-N-Out's request to stop Chadder's from operating its restaurant because its layout, interior and exterior decor and employees' uniforms were too similar to that of the California chain.

Since In-N-Out filed its lawsuit, Stewart noted Chadder's has changed the color of its employees' aprons and hats from red to blue; the border of its menu boards and other signs from red to blue; the background color of its menu board from white to yellow; the font on its menu board; and the trim color on its outside signs from red to blue.

"The court finds that, at this time, In-N-Out has not met its heightened burden of showing that it is entitled to an injunction against the use of its claimed trade dress," Stewart wrote.

Chadder's attorney could not be immediately reached for comment on the ruling.

In-N-Out's Attorney Arnold M. Wensinger, in a e-mailed statement, said Stewart's ruling "vindicates our belief that Chadder's has violated our registered trademarks."

"We also believe that we have a strong case showing that Chadder's has violated our unique trade-dress (i.e., look and feel) by purposely intending to blur the lines between our business and their own. We have always fought to protect our trademarks as well as our unique look and feel and we will continue to do so in this matter," Wensinger said.

This story appeared in The Daily Herald on page A1.