Reliable MSK-8420B - Manual (Page 11)

25
24
23
22
button
balance wheel
pressure adjusting screw
reduce
increase
teeth - belt pulley
shaft
safety clutch device
-8-
needle thread tension
increase
reduce
b. If the needle thread is too loose and the bobbin
thread is too tight, then shows as Fig. 20C, And
turn the thread tension screw clockwise to increase
the needle thread tension; or turn loose the
bobbin lace screw to reduce the bobbin thread
tension. (See Fig. 21, 22)
For special sewing with special thread, the ten-
sion needed can be obtained by adjusting the power and
stroke of the thread take-up spring.
5.2 Adjusting the pressure of presser foot (Fig.23)
The pressure of the presser foot should be adjust-
ed according to the thickness of the sewing materials.
If stitch on heavy duty material, the pressure should
be increased and turn the pressure adjusting screw on
the back of the arm clockwise if reduce the pressure,
turn it counter-clockwise.
5.3 Use and adjustment of the safety clutch device
The function of the safety clutch device is to
prevent the hook and teeth-belt from destroy when the
needle thread is drawn into the hook for adnormal load
during the operation.
5.3.1 The function of the safety clutch device(Fig.24)
a. When the safety clutch device is functioning,
the teeth-belt will remove the load and the rock
shaft will stop rotating, only the upper shaft
rotates, and the machine stops work.
b. Clean off the needle thread which is drawn in
the hook.
c. Turn the shaft of the teeth-belt with hand to
check if the rock shaft can turn smoothly, then
reset the safety clutch device.
5.3.2 Resetting the safety clutch device.
a. While press down the button in the bed surface
with left hand, turn the balance wheel slowly
with right hand in the direction shown in Fig.
25.