CHICAGO -- A former clerk for Sears, Roebuck & Co. has settled his dispute with the retail company over profits from a popular socket wrench he invented in 1964. Peter Roberts of Tennessee was 18 years old when he invented a quick-release wrench that eventually sold by the millions. Roberts, now 44, last week settled an $8.2 million patent infringement case that alleged Sears had cheated him out of his rightful royalties. Sears spokeswoman Kathy Gucfa would not give any details of the agreement, saying part of the settlement is that neither side will comment. Roberts was believed on his way home to the Chattanooga suburb of Red Bank and couldn't be reached for comment. His attorney John Davidson declined to comment. Roberts was a clerk at a Sears store in Gardner, Mass., when he invented the wrench in his spare time. The wrench has a push button that permits removal of sockets from the tool with one hand. He obtained a patent for the wrench design in 1965, and Sears paid him $10,000 for rights to the patent. He then joined the Air Force. While stationed in England, he saw a Sears catalogue and was astounded at the display the wrench got because, he said, Sears led him to believe the tool had only minor sales potential. But from 1965 to 1975, Sears sold 19 million of the wrenches for a net profit of more than $44 million, according to documents in the case. In 1969, Roberts sued seeking to rescind the agreement under which he assigned the patent to the company. A federal jury in 1978 awarded him $1 million after finding that Sears fraudulently obtained the patent. Roberts also asked for damages for the 14 million socket wrenches sold after 1977. He had estimated Sears earned $172 million from sales of the wrench from 1977 to 1982, but attorneys for the retailer said the profit was closer to $5 million. In April 1982, a federal jury found that Sears violated the patent and awarded Roberts $5 million, an award later increased to $8.2 million by the judge on the grounds the infringement was willful. That decision was overturned in 1983 by an appeals court, which ordered a new trial. The new trial was in its fifth day Friday when the settlement was reached.