Hiscox, Gardner Dexter, 1822?-1908 · New York, The Norman W. Henley publishing co. · leaf 310
MINING, 299 … 1203. COAL-CUTTING MACHINE, Ingersoll-Sergeantmodel. The piston and drill rod are automatically operated by thealternating motion of two piston valves. Operated by compressedair, and only has to be held against the coal wall to under-cut, whenthe face can be broken down.
Mechanical movements
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