Wal-Mart sues Kmart over patented checkout device

The world's largest retailer, Wal-Mart Stores Inc., Bentonville, Ark., filed a lawsuit yesterday in a Delaware federal court against rival discounter Kmart Corp., Troy, Mich. Wal-Mart's suit alleges infringement of a patent for a rotating device that checkout clerks use in loading bags. Wal-Mart seeks a jury trial, unspecified damages and an order prohibiting Kmart from using the device designed to speed up the checkout process. Wal-Mart first filed a last-minute objection over the device with the bankruptcy court in May, nearly derailing Kmart's exit from Chapter 11.