ALEXANDRIA, Va., June 10 -- United States Patent no. 12,291,925, issued on May 6, was assigned to Center Rock Inc. (Berlin, Pa.).
"Underreamer drill hammer" was invented by Warren Thomas Lay (Catawba, Va.) and Austin C. Hine (New Florence, Pa.).
According to the abstract* released by the U.S. Patent & Trademark Office: "An underreamer drill hammer comprising a canister including a housing having an outer diameter, a proximal end configured for attachment to a drill string, and a percussive drill hammer housed within the housing, the percussive drill hammer having a drill bit movable between a radially retracted position and a radially extended position. The drill bit can rotate and is designed in a manner that the drill bit head cams, piv...