Janome MC9900, Руководство по обслуживанию

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16
Mechanical adjustment
Backlash between hook drive gear and lower shaft gear
The rotary play of the hook should be 0.8 mm or less when the tip of rotary hook is within the width of feed dog.
1. Remove the presser foot, the needle plate and the bobbin
holder. (see page 4 and 5)
* Cover the needle plate with the fabric to prevent
damaging the needle plate when removing.
2. Remove the base cover and bed cover (see page 3 and 4).
3. Turn the handwheel toward you so the the tip of the
rotary hook is within the width of feed dog as shown in
figure 1.
Check the rotary play of the hook.
4. If the backlash is too much or too little, loosen the
hexagonal socket screw (C) and (D) and following the
adjustment procedure.
If the backlash is too great (more than 0.8 mm), turn the
both lower shaft bushings in direction A. If the
engagement of gear is too tight, and the machine does
not turn smoothly, turn the both lower shaft bushings in
direction B.
Adjust the grooves of the lower shaft bushing as well.
5. Tighten the hexagonal socket screws.
• Check the hook adjustment and needle bar height
after this adjustment (see page 18 and 19)
Fig. 1
Tip of rotary hook
Width of feed dog
0.8 mm or less
Hexagonal
socket screw (C)
Lower bushing of the front side
Lower shaft bushing
Lower shaft gear
Lower shaft gear
Hook driving gear
A
B
Lower bushing of the belt cover
Lower shaft bushing
Hexagonal
socket
screw (D)