Hitachi DH 24DV, Технические данные и руководство по обслуживанию

Страница: 26 / 39

--- 23 ---
The service life of a drill bit with a diameter of 8 mm is approximately 300 holes when drilling into concrete with a
depth of 30 mm. If reground before the end of its service life, the drill bit will continue to provide efficient drilling.
Figure 8 shows the regrinding angle.
Regrinding angle of drill bit
Rotation
direction
Fig. 8
Forward
Washer (B)
Holder plate
Holder spring
Key rails
(two pieces)
Steel ball
Stopper ring
Fig. 9
Grip
Ball holder
Front cap
Cylinder
8-6. Tool Retainer Section
Figure 9 shows the construction of the chuck section.
The tool retainer is structured as shown in Fig. 9.
The tip of the tool retainer is covered with the front cap (made of rubber) to prevent dust and chips from getting
inside. The steel ball falls into the round groove of the bit to prevent the tool from coming off and the two key rails
transmit the rotation torque. To mount the bit, push the bit in the tool retainer as far as it will go. Pushing lightly,
turn the bit until it is caught. At this position, push the bit in as far as it will go (sliding the grip is not required for
mounting the bit). To remove the bit, slide the grip backward to the full and remove the bit.
Backward