| 摘要 |
PROBLEM TO BE SOLVED: To provide a rock drill head excellent in versatility capable of forming an uneven step section in an internal wall surface of a bore with excellent working efficiency and irrespective of a formation state of the bore and a rock drill device. SOLUTION: Except when external force is given to a head body 102 resistant to energizing force of a coil spring 123 to compress the coil spring 123, head movable members 112 and 114 are in a state to approach to each other in the direction of the diameter with the center axis of the bore 3 as the center, in other words, it is in a state to shorten the diameter. Accordingly, even if a diameter widening head 100 is set in any direction, the head movable members 112 and 114 are not projected from an aperture 121 unless external force in excess of predetermined one is impressed, a diameter widening process can be carried out to an optional bore 3, and versatility can be greatly enhanced. COPYRIGHT: (C)2004,JPO&NCIPI
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