ALEXANDRIA, Va., June 9 -- United States Patent no. 12,286,843, issued on April 29, was assigned to The Charles Machine Works Inc. (Perry, Okla.).

"Dual pipe drill head quick interchange joint" was invented by Greg L. Slaughter Jr. (Perry, Okla.), Travis W. Woodson (Orlando, Okla.) and Joseph G. Greenlee (Perry, Okla.).

According to the abstract* released by the U.S. Patent & Trademark Office: "A system for connecting a drill bit and pipe puller to a drill string. The system includes a downhole tool having an internal cavity and a through-hole in its wall. A coupler may be slidingly received in the cavity and connected using one or more fasteners which interconnect a groove in the coupler to the wall of the downhole tool. Fasteners used m...