| 摘要 |
PROBLEM TO BE SOLVED: To provide a drilling device of a step mounting hole which improves work efficiency.SOLUTION: A drilling device 1 comprises: a pair of left and right drills 5, 5; a drill holder 6 for holding the drills 5, 5 integrally; a guide member 7 attached to the drill holder 6; and a support member 8 which is fixed to an inner wall surface 2a of a manhole 2, and to which the guide member 7 is connected detachably. Thus, during the drilling, the reaction force can be absorbed by the support member 8. Moreover, when positioning the drills 5, 5 to a drilling position, because the positioning can be performed with a simple operation of connecting a hook-shaped connection part 45 of the guide member 7 to the support member 8, it is possible to improve work efficiency. |
