JUKI MOL-254 Engineer's Manual page 37

Adjustment Procedures
① Remove tension release return spring
② Loosen two setscrews
stopper in the direction of the arrow mark ( ⇨ ) while
making the tension release stopper closely come in cantact
with the tension release adjusting arm. Then the clearance
provided between the cam follower and the tension release
arm pin becomes smaller, and when pressing the stopper
in the direction of the arrow mark (
becomes larger.
③ Adjust the clearance to 1.0 mm and tighten two setscrews
to fix the stopper. At this time, make end face
tension release stopper closely come in contact with the
worked plane of the machine arm.
④ When the adjustment is completed, hook the tension
release return spring on the spring suspension bracket
and the tension release stopper.
(Caution) After having adjusted the position of the
t ens io n re lea se st o p p er, p erfo r m th e
adjustment of releasing amount of the thread
tension disk of the next item.
1) Remove the top cover and make sure that tension release
pin rides on tension release notch
2) If not, press by hand cam follower
to rotate the main shaft in the normal direction of rotation
and make the state as shown in the figure on the left.
3) In the state as shown in the figure, loosen setscrew
the tension release adjusting arm and move tension
release adjusting arm
releasing amount of the tension disk will vary.
H type : 0.6 to 0.8
(Caution) If the releasing amount is excessively small,
length of remaining thread after thread
trimming will vary. On the contrary, if it is
excessively large, defective disk closing after
releasing the disk releasing operation will
result.
.
and press the tension release
), the clearance
.
in the direction of ⇨
to the right and left. Then the
30
− −
Results of Improper Adjustment
○ If the clearance is excessively
large, when adjusting the
releasing amount to a rather
extensive value, the disk is not
f u l l y c l o s e d . A s a r e s u l t ,
defective sewing will result.
○ If there is no clearance, defective
operation of the thread trimmer
shaft (a load is applied) will occur
resulting in failure of thread
of the trimming or machine-lock.
○ If the releasing amount of the
tension disk is excessively small,
length of remaining thread after
thread trimming is reduced or the
variation of the length will be
in
increased.
○ If the releasing amount of the
tension disk is excessively large,
the disk is not fully closed after
releasing the disk releasing
operation resulting in defective
sewing.