Drilling device for earth drill
Number of patents in Portfolio can not be more than 2000
United States of America Patent
Stats
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Apr 25, 2006
Grant Date -
Sep 2, 2004
app pub date -
Apr 25, 2002
filing date -
Apr 25, 2002
priority date (Note) -
Expired
status (Latency Note)
Importance
Abstract
Locking elements 3d and 3j are provided at an inner member 3 connected to a kelly bar 1, and a locking element bearing plate 6f is provided at an outer member 6. The outer member 6 includes a cylindrical bucket 7 and a grab bucket 8 housed inside the cylindrical bucket 7. When an excavating tool 2 is in its most contracted state, the inner member 3 is rotated forward to lock the locking elements 3d and 3j at the locking element bearing plate 6f, thereby disallowing relative vertical movement of the inner member 3 and the outer member 6. As the excavating tool is rotated by applying a force to the kelly bar 1 along the lifting direction in this state, an excavating operation can be executed while applying a load smaller than the load of the excavating tool 2.
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