–
31
–
Adjustment Procedure
Results of Improper Adjustment
Checking items:
❶
Right hand needle
❷
Lower looper blade point
❸
Lower looper
❹
Gauge needle (Cut the top end of needle for use. L = 31.58 mm)
* Check that the clearance between the needle
❶
and the lower looper
blade point
❷
is 0 to 0.05 mm (E).
* Turn the handwheel and check that the lower looper blade point
❷
meets with the left side of gauge needle
❹
when lower looper
❸
goes
and back.
(Insert the gauge needle into the needle hole for the right needle.)
How to perform adjustment:
○
Loosen the setscrews (C) of the lower looper support arm (D).
○
Move the lower looper support arm (D) back or forth and adjust the
clearance between the needle
❶
and the lower looper blade point
❷
.
○
Retighten the setscrews (C).
○
Adjustment of the lower looper cam timing.
・
Loosen the setscrews (A) of the lower looper cam (B).
・
Check the position of the lower looper blade point
❷
and the gauge
needle
❹
while turning the lower looper cam (B). Change the posi-
tion of the cam little by little so that the left side of gauge needle
❹
can meet with the lower looper blade point
❷
on both ways of going
and back.
・
Retighten the setscrews (A).
If the clearance between the nee-
dle and the lower looper is larger
than the standard adjustment
value, needle thread skipping can
be caused.
If the clearance between the
needle and the lower looper is
smaller than the standard adjust-
ment value, the needle comes in
contact with the looper, resulting in
needle breakage or needle thread
skipping can be caused. In addi-
tion, the looper blade point can
be damaged, resulting in thread
fraying and thread breakage.
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