| 摘要 |
PROBLEM TO BE SOLVED: To provide a drill head improved in drilling efficiency without a possibility of loosening in screw joining between the drill head and a cleaning swivel even if an drill rod is separated or additionally joined. SOLUTION: In the drill head, a shank rod, a rotation drive device for rotating the shank rod, and a hammering device for hammering the shank rod are embedded in a transmission housing. A joint adaptor rotatable with the shank rod is integrally connected to the lower end of the shank rod. The section of the joint adaptor is covered with a seal case continuously provided for the transmission housing to form the cleaning swivel. COPYRIGHT: (C)2011,JPO&INPIT
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