| 摘要 |
Provided is a hole-drilling device for drilling a hole with an expanded diameter hole portion, the hole-drilling device realizing a simplified structure. One example of the hole-drilling device for drilling a hole with an expanded diameter hole portion according to the present invention includes: a body (1) including a shank; a sleeve (3) attached to the body such that the sleeve is movable in a front-rear direction; a compression spring (6), which urges the sleeve forward relative to the body; a drill bit body (4) configured such that a proximal end portion of the drill bit body is inserted in a bottomed insertion hole (11) of the body, the drill bit body being attached to the sleeve such that the drill bit body is movable in the front-rear direction; an expanded diameter hole portion forming member (5) attached to a side surface of the drill bit body and configured such that a cutting bit (5a) protrudes laterally from the drill bit body when the expanded diameter hole portion forming member moves forward on the side surface; a compression spring (7), which urges the expanded diameter hole portion forming member rearward relative to the drill bit body; and a cam (8), which is rotatably supported by the body and whose both ends are contacted by an inner wall of the sleeve and the expanded diameter hole portion forming member. The expanded diameter hole portion forming member is configured to move forward on the side surface of the drill bit body owing to rotation of the cam (8) when the body moves forward relative to the sleeve. |
