JUKI LU-2800 Series Engineer's Manual page 55

Adjustment procedures
1) Position of the counter knife and the clamp spring
[Position of the counter knife]
Loosen setscrews ❶ (1-needle: 2 positions, 2-needle: 4 posi-
1.
tions) of the counter knife.
Press the edge of counter knife ❸ against the step difference
2.
of counter knife base ❷ .
3. Adjust so that the distance from mounting groove of the slide
plate to top end of the counter knife ❸ is 37 ± 0.1 mm (A) (LU-
2818-7, 2868-7 : 34.5 ± 0.1 mm).
Tighten setscrews ❶ (1-needle: 2 positions, 2-needle: 4 posi-
4.
tions) of the counter knife.
[Position of the clamp spring]
Loosen setscrews ❹ (1-needle: 2 positions, 2-needle: 4 posi-
1.
tions) of the clamp spring.
Press the edge of clamp spring ❺ against the step difference
2.
of counter knife base ❷ .
Slide the clamp spring ❺ while making it press against the step
3.
difference of the counter knife base ❷ , and adjust the distance
to 3.7 ± 0.1 mm (B).
Tighten setscrews ❹ (1-needle: 2 positions, 2-needle: 4 posi-
4.
tions) of the clamp spring.
(Caution) When the position of counter knife ❸ and clamp
spring ❺ is moved, re-adjust the position of counter
knife base ❷ and the knife pressure.
Results of Improper adjustment
When dimension A is larger :
Length of bobbin thread clamp
o
is shortened and stitch skipping
occurs.
Setting/taking out bobbin cannot
o
be performed.
When dimension A is smaller :
Thread trimming failure will be
o
caused.
When dimension B is larger :
Bobbin thread clamp failure oc-
o
curs.
Stitch skipping at the start of
o
sewing will be caused.
When dimension B is smaller :
It is difficult to take out cloth
o
since needle thread have been
clamped, and the trouble that
bobbin thread clamp is simulta-
neously removed will be caused.
Clamp spring ❺ interferes with
o
the rear edge of moving knife.
As a result, deformation of clamp
spring ❺ or the like will occur.
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