JUKI LH-4128-7 Engineer's Manual page 19

4) Needle clamp
1. Turn the hand wheel and align the engraved line "B", which is the third
one from the bottom of the needle bar, with the lower end of the needle
bar lower bushing . (A rise of 2.2m) At that time, the distance between
the upper end section of the needle hole and hook's blade point is
1.2mm in standard practice.
2. The above-mentioned adjustments are required when the needle DPX5
is used. When using the DPX17 needle, adjustments of "C" and "D"
should be carried out.
3. If standard values cannot be secured, remove the needle clamp screw
and rotate the needle clamp
amount of adjustment: 0.6mm). Otherwise, remove the spring hold
setscrew and rotate the spring hold
adjustment: 0.3mm).
5) Needle entry
o LH-4128, LH-4128-7
1. Minimize the feed amount by rotating the feed adjusting dial.
2. Turn the handwheel to bring needle bar
3. Loosen the setscrew
4. Turn the needle bar
needle enters the center of the needle slot in the feed dog
the adjustment, tighten the screw
5. If needle is longitudinally dislocated in the needle slot in the feed
dog, loosen clamping screw
position of the needle by turning feed base arm
the arrow. After the adjustment, tighten screw
(Caution) 1. Do not change the needle bar
2. Do not loosen needle clamp
o LH-4168-7, LH-4188-7
1. Minimize the feed amount by rotating the feed adjusting dial.
2. Turn the handwheel to bring needle bar
3. Loosen clamping screws
4. Turn the needle clamp
the needle slot in the feed dog
tightening screws
5. If the needle seems to be displaced forward or backward in the slot
of the feed dog, loosen the feed bar arm tightening screw
the feed base arm
tightening screw .
(Caution) 1. Needle clamp
provided between screw
leftmost edges on the slot in the needle bar
Adjustment Procedure
by one turn for adjustment (the
by half turn (the amount of
to the lowest dead point.
of the needle bar connection
in the direction of the arrow to adjust so that the
.
in feed rocker and adjust the longitudinal
to the lowest dead point.
and .
so that the needle
. After adjustments, tighten the
and .
. After adjustments, tighten the feed bar arm
can be turned in the clearance
.
. After
in the direction of
.
height.
.
enters the center of
to rotate
and the rightmost and
.
– 15 –
Results of Improper Adjustment
o Stitch skipping and thread
breakage will be caused.
o Poorly tensed seam will result.
o W h e n t h e f e e d d o g h a s
elongated needle slots (2.2mm
x 3.2mm), the needle thread will
be loosened if the needles enter
the far end of the respective
elongated slots viewed from the
operator.
* If needle entry is performed on
the operator side at the time of
thread trimming, this can be a
cause of failure in thread
trimming.