| 摘要 |
PURPOSE:To make insertion and guide work easy and to improve the workability of a densist without being obstructed by a lip (cheek) at the time of boring work, by shifting a bar mount part to the right (for left teeth) or left (for right teeth) from the center line of a grip part in the longitudinal direction thereof. CONSTITUTION:A vertical rotary shaft 2a has a cavity along the axial center thereof and the upper part of a bar 6 is engaged with said cavity to be chucked. Therefore, the rotatory power from the external motor is transmitted to a horizontal rotary shaft 1a and the rotatory power thereof is transmitted to the second horizontal rotary shaft 5 through a bevel gear 4 to be further transmitted to the vertical rotary shaft 2a by the bevel gear 4 and the bar 6 chucked by the rotary shaft 2a rotates. Because of the presence of the second horizontal rotary shaft 5, even when the bar mount part 2 is shifted to the right or left from the center line O of a grip part 1 in the longitudinal direction thereof, driving force is transmitted to the bar mount part 2. Since the bar mount part 2 is shifted to the left from the center line O of the grip part 1 in the longitudinal direction thereof, when the leading end part of an engine head is inserted in the oral cavity in an X-direction easiest to insert and the engine head is shifted to the right or left at a relative position, the bar 6 can be guided to an objective position from the gap between adjacent teeth.
|
