Rotary head tunneling machine having oppositely rotating head portions
United States Patent 2766978
US Patent References:
Horizontal earth-boring machine
- - 1511957

Tunneling machine
- - 1674870

Mining machine
- - 1888085

Apparatus for drilling wells
- - 1904522

Drilling apparatus
- - 2250670


Inventors:
Robbins, James S.
Publication Date:
10/16/1956
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Assignee:
GOODMAN MFG CO
Primary Class:
299/60
Other Classes:
299/31, 299/110, 175/319
International Classes:
E21D9/11; E21D9/10
US Patent References:
2575975Rock drill
2694563Rotary mining machine head and cutter carried thereby movable in elliptical paths
2719708Pan guideway for rotary mining head