JUKI lbh-1790 series Engineer's Manual page 13

Adjustment Procedures
1. Make the height of knife return stopper 1 10 mm from the
work plane of the machine arm and fix it with nut 2. (Adjustment
of initial position of the knife)
2. Adjust the position of solenoid installing base 4 so that the
clearance between cloth cutting knife solenoid 3 and the
cushion is 14 mm, and fix it with four screws. (Adjustment of
stroke)
3. Fix knife bar bracket 6 so that the clearance between knife
bar base 5 and the edge of the machine arm is 4±0.5 mm.
(Adjustment of initial position of the knife)
4. Adjust knife installing base 9 so that the clearance between
needle bar 7 and knife 8 is 0.5±0.1 mm.
(Caution)
1. Be careful of the clearance between the throat plate and
knife 8 when adjusting knife bar bracket 6, knife bar
base 5 and knife installing base 9.
2. Fix solenoid installing base 4 so that it is not tilted.
Results of Improper Adjustment
™ If the distance of 4 mm is
excessively small, the knife
installing base comes in contact
with the jaw section of the
machine arm and a big noise
occurs.
™ If the distance of 4 mm is
excessively large, the knife may
come out under the presser
when the presser is lifted.
™ If the distance between cloth
cutting knife and needle bar is
small, the knife comes in contact
with needle bar and abnormal
noise, worn-out of knife or stain
of cloth may occur.
™ If the distance between cloth
cutting knife and needle bar is
large, the distance from the front
bar-tacking to knife hole is
increased and the rear bar-
tacking may be cut.
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