1878US200936A
Mining / Coal
Improvement in Coal-Drills
A toothed, threaded tapering cylinder anchors in coal and supports and guides a screw-fed drill advanced by an adjustable crank and hinged nut.
Open original patentInventor file
James Joseph Rigney
1 patent record is preserved in this collection. The list describes the patents; it does not add biographical claims beyond the available records.