JUKI lbh-1790 series Engineer's Manual page 35

Adjustment Procedures
1. Align shaft end 1 of solenoid with the edge of thrust collar 2.
2. Assemble thread tension connecting plate 3 in the direction
as shown in the figure.
3. Adjust so that thread tension connecting shaft 5 protrudes by
2 to 2.5 mm from adjustment nut A 4 and that stroke is 1±0.3
mm using adjustment nut B 6.
1. It is proper that thread take-up amount of thread take-up spring
1 is 8 to 10 mm and that the strength of the start of moving is
approximately 0.06 to 0.1N.
2. To change the moving amount of thread take-up spring 1,
loosen screw 2, put a thin screwdriver in the slit of tension
post 3 and turn the screwdriver to adjust the moving amount
of the thread take-up spring tension.
3. To change the strength of thread take-up spring 1, put a thin
screwdriver in the slit of tension post 3 and turn the screwdriver
in the state that screw 2 is tightened. Turning clockwise
increases the strength of thread take-up spring, and
counterclockwise decreases the strength of the thread take-
up spring.
(Caution) Assemble this thread tension after pressing until
it will go no further.
Results of Improper Adjustment
™ When the dimension value,
1± 0 . 3 m m i s e x c e s s i v e l y
improper, proper needle thread
tension cannot be obtained and
sewing failure occurs.
™ When the direction of thread
tension connecting plate 3 is
improper, the plate comes in
contact with the machine frame
or the like and malfunction
occurs.
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