JUKI MF-7900 Series Engineer's Manual page 85

Adjustment procedures
(1) Adjusting the Lower knife
Set lower knife ❹ and lower knife holder ❺ with setscrews ❻
1.
at the position of the illustration.
(2) Adjusting the position of clamp pressure adjusting spring
Loosen screws ❾ .
1.
2. Adjust so that a clearance of 2.5 ± 0.5 mm is provided between
the top end of clamp pressure adjusting spring  and the top
end of lower knife ❹ when the lower knife ❹ is brought to the
rightmost position.
After the adjustment, tighten screws ❾ .
3.
(3) Adjusting the knife engagement and the knife pressure ad-
justing spring
Loosen screws ❼ and ❽ , and adjust the position of upper
1.
knife  so that the engagement of the upper knife  with the
lower knife ❹ is 0.5 mm when lower knife ❹ moves to the ex-
treme right.
2. At the same time, adjust so that a clearance of 0.5 to 1 mm is
provided between knife pressure adjusting spring  and clamp
pressure adjusting spring  .
After the adjustment, tighten screws ❼ .
3.
(4) Adjusting the pressure of clamp spring
1. The looper thread is held by clamp pressure adjusting spring
 after thread trimming.
2. Holding pressure of the looper thread can be adjusted by turn-
ing screw ❽ .
When screw ❽ is turned clockwise, the holding pressure is
3.
increased and turned counterclockwise, the pressure is de-
creased.
4. Make the holding pressure as low as possible within the range
of holding the looper thread.
Results of Improper adjustment
– 71 –