JUKI MEB-3810N Series Instruction Manual page 84

Needle inside
3)
Direction A :
Timing advances.
Direction B :
Timing retards.
No clearance is
provided
Rear
❻
4)
Needle outside
Stitch bite
width : small
❸
A
Front
B
Pressed against the
part located behind
Stitch
bite width
: large
− 81 −
3) Adjust with looper driving cam ❸, so that the blade
point of the left looper is aligned with the center of
the needle when the needle bar goes up 3 mm from
the lower dead point of the inside needle. Then, fix
the looper driving cam by tightening two setscrews
❻ with driving cam ❸ pressed against the part
located behind it.
If stitch skipping due to the loop bending
caused by faulty scooping of thread by the
looper occurs when the needle throwing
width is 2 mm or less, shift the looper driv-
ing cam in direction A to change the looper
timing so that the left looper blade point is
located at the center of the needle when the
needle bar goes up from the inside lower
dead point by 2.7 to 2.8 mm.
4) Similarly, check the position of the needle and that
of the blade point of the looper when the needle
bar goes up 3 mm from the lower dead point of
the outside needle. The blade point is positioned
approximately in the range of the left side of the
needle. When it is outside the range, check again
steps 2) and 3).
After performing the looper timing adjust-
ment, when the stitch bite width is changed
in case of ① to ③ described below, perform
steps 1) to 4) whenever the case occurs.
① When the stitch bite width in terms of
that at the time of looper timing adjust-
ment is changed more than ±0.3 mm.
Even when the change of the stitch bite
width is within ±0.3 mm :
② When the stitch bite width is more than
3.4 mm.
③ When sewing heavy-weight materials or
overlapped section where needle is apt
to be bent.