JUKI LH-4128-7 Engineer's Manual page 27

1. Turn the hand wheel
needle bar.
2. Confirm that the engraved marker line
to the upper plane
sprocket is located on the worker side.
3. ATurn the hand wheel
o LH-4188-7 : Let the machine stand still with the needle bar left
(= 180°) positioned at the lower dead point.
o LH-4128 (-7) : Make a reverse rotation by 13.6mm with the hand
LH-4168-7 : wheel
(= 167.5°)
4. Adjust the lower shaft to the position where the needle bar does not
rock in the feeding direction even though the hand wheel
the lower shaft is turned, and the reverse feed lever is pushed.
(At that time, the engraved marking dot
coincides with the engraved marking line
(-7), LH-4168-7).
5. Fasten the first screw
.
(The third screw is used for bottom feed.)
Adjustment Procedure
until it reaches the lower dead point of the
of the sprocket is in parallel
of the bed and that the first screw
to the adjusting position.
positioned on the outer periphery.
of the sprocket and then the second screw
of the
is fixed,
of the lower shaft almost
of the sprocket. LH-4128
– 23 –
Results of Improper Adjustment
If the timing between the main shaft
and lower shaft does not match,
thread trimming timing, needle
entry in the feed dog slot and the
feeding phase will change.
The thread tension and puckering
will also change.
When the stitching pitch changed,
the hook timing deviation becomes
large.