ALEXANDRIA, Va., June 6 -- United States Patent no. 12,281,726, issued on April 22, was assigned to The Charles Machine Works Inc. (Perry, Okla.).
"Pipe extraction assisted by pre-stressed strand" was invented by Robert F. Crane (Nekoosa, Wis.), Mark D. Randa (Oconomowoc, Wis.) and Steven W. Wentworth (Scottsdale, Ariz.).
According to the abstract* released by the U.S. Patent & Trademark Office: "A machine for extracting a ductile pipe. The machine has a vise which can grip the pipe, and a wire clamp. Each of the wire clamp and vise are supported on a carriage which is movable relative to a frame. This enables the vise to grip and pull the ductile pipe. Additionally, a wire strand may be disposed through the pipe from a far end to the end...