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1) Releasing Torque Adjustment
Change the pressure of the safety clutch (if the safety clutch is hard to
be released or it is released too easily) following the procedure de-
scribed below.
1. Remove the timing belt from the lower sprocket
.
2. When the adjusting screw
is fastened, the pressure of the safety
clutch will be increased. When the adjusting screw is loosened, the
pressure of the safety clutch is decreased.
3. Fix the lower sprocket
and turn the safety clutch bushing
until
the safety clutch pawl
comes off the groove on the safety clutch
bushing
. A torque developed at the time when the safety clutch
pawl comes off the groove is taken as the releasing torque.
4. Adjust the standard releasing torque to 13.23
±
1.47N•m (135
±
15kgf•cm).
5. After adjustment, put the timing belt on the lower sprocket.
(Refer to [5.-(3) How to replace the Timing Belt] for how to put the
timing belt on the lower sprocket).
2) How to reset the Safety Mechanism
If an excessive load is applied to the hook driving shaft, the safety clutch
will be released. In this case, the hook will not rotate even if the hand-
wheel were turned.
1. Reset the safety mechanism with the machine head tilted.
2. Insert the screwdriver (medium)
supplied with the machine into
the hole
A
in the safety clutch bushing
.
3. Hold the screwdriver (medium)
supplied with the machine by hand
to prevent the safety clutch bushing
from turning, and rotate the
hand-wheel in the reverse direction.
4. When the safety clutch clicks, the safety clutch pawl
fits in the
groove on the safety clutch bushing
. This completes the resetting
procedure of the safety clutch.
Adjustment Procedure
Results of Improper Adjustment
o If the releasing torque is set to an
excessively high value:
• The hook, hook driving shaft
gear or related components will
break.
o If the releasing torque is set to an
excessively low value:
• The safety clutch will be re-
leased too easily. His will impair
smooth operation of the sewing
machine.
