−
60
−
0.3
±
0.2
(1)
(2)
6. BOBBIN CASE WITH IDLE-PREVENTION SPRING
For the DDL-9000 series, bobbin case with idle-prevention spring is used.
Adjust the tension of the idle-prevention spring in the following procedure.
When the bobbin runs idle
Increase the tension of the idle-prevention spring.
When the thread is not well tightened
Decrease the tension of the idle-prevention spring.
* Adjusting the idle-prevention spring
1) Insert an old sewing needle or the like into the bobbin as shown in the illustration, and remove the spring in a
manner of just lifting it.
(Prevent the spring from jumping out with your thumb.)
2) To change the pressure of the spring, change the height of arched section of the spring.
(Take care so that the free end pf the spring does not rise from the bobbin case.)
3) First, set the ear (1), insert a sewing needle into the bobbin, and set the ear (2) in the state that the central part
of the spring is raised.
(Part No. of bobbin case spring : D1837555B0B)
To change
the height
* When using the bobbin case with idle-prevention spring, be sure to set it in the direction of winding as shown in
the illustration.
(Irregular stitches at high or low speed)
When the thread is excessively tightened at low speed
Adjust the tension of bobbin thread and that of
idle-prevention spring to rather higher.
When the thread is insufficiently tightened at low spped
Adjust the tension of bobbin thread and that of
idle-prevention spring to rather lower.
* When idle running of bobbin or irregular stitch at high or low speed makes troubles, it is effective to use the
bobbin case with idle-prevention spring.
1)
2)
3)
Ear
Rotation of bobbin
When the bobbin case
without idle-prevention
spring is used.
Rotation of bobbin
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