Combined mine drill, timber jack, and mine post
United States Patent 2556357
US Patent References:
Mine roof and timbering jack
2532168

Screw thread device
1937547

Adjustable shore
1776439

Drill support
1524711

Mine jack
1514262


Inventors:
Baldwin, John C.
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Publication Date:
06/12/1951
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Assignee:
Baldwin, John C.
Primary Class:
173/35
Other Classes:
173/42, 248/354.400, 248/200.100, 173/36, 254/13, 173/145
International Classes:
E21B15/00; E21D15/24; E21D15/00
US Patent References:
1450709Column or support for rock drills
1189901N/A
0977734N/A
0965024N/A
0861373N/A
0689766N/A
0685011N/A
Foreign References:
FR372509A
GB190926630A
AU114575B