4. Looper adjustment
WARNING :
Perform the work after turning OFF the power to prevent accidents caused by the abrupt start of the
sewing machine.
(1) Looper return
When each looper ( 1 , 2 and 3 ) is at the most left position, the standard distance from the tip of each looper ( 1 , 2
and 3 ) to the center of each needle ( 4 , 5 and 6 ) is 3.6 mm.
1)
Standardization of the front looper
When front looper 1 is at the most left position, measure the distance from the tip of front looper 1 to the center of
left needle 4 with scale 7 and adjust the distance to the standard value, i,e, 3.6 mm.
2)
Standardization of middle and rear loopers
When the tips of the middle and rear loopers ( 2 and 3 ) are simultaneously aligned with each left surface of the
middle and right needles as well as the tip of the front looper 1 with the left surface of the left needle 4 , the middle
and rear loopers are in the standard positions.
Alignment
3
2
1
Right-left direction
3.6mm
1
Front-rear direction
9
8
!7
!6
!3
!8
5
6
4
Alignment
4
7
!4
8
1
!1
!2
!0
!5
− 27 −
For the front looper 1 , the looper return is
adjusted with the gauge 7 and a scale, and
for the middle and rear loopers ( 2 and 3
) , the looper return is adjusted by aligning
the tips of the middle and rear loopers ( 2
and 3 ) with the left surfaces of the needles (
5 and 6 ), respectively.
(2) Front looper
Loosen the setscrews 8 to remove the throat plate 9 .
1)
Mount the front looper 1 on the front looper base !0
2)
and tighten the setscrew !1 .
3)
Rotate the handwheel in the direction of reverse
rotation, move front looper 1 to the most left position,
and measure the clearance from the tip of front looper
1 to left needle 4 with scale 7 .
4)
For adjusting the clearance to the standard distance, loosen
the setscrew !2 securing the front looper base to adjust the
position of the front looper base !0 in the right-left direction.
5)
After adjustment, tighten the setscrew to secure the
front looper base setscrew !2 .
(3) Middle looper
1)
Rotate the pulley counterclockwise and align the tip
of the front looper 1 with the left surface of the left
needle 4 .
Mount the middle looper 2 on the middle looper base
2)
!3 and tighten the setscrew !4 .
Loosen the setscrew !5 securing the middle looper
3)
base and move the middle looper base !3 in the right-
left direction to align the tip of the middle looper 2
with the left surface of the right needle 5 .
After adjustment, tighten the setscrew !5 to secure
4)
the middle looper base.