Unicorn LT2-H650, Руководство по эксплуатации, каталог запасных частей

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THE TROUBLE CAUSE OF THE THREAD TRIMMER AND THE MEASURE
Trouble Cause Measure Reference
Thread is not
trimmed.
① Roller does not rest onto cam groove
when needle is at the lowest position.
② The fixed knife is not in positive
engagement with the driving knife.
③ The driving knife is improperly located.
④ Machine stop position timing is too
advanced.
⑤ Thread trimmer cam is improperly
adjusted.
∘ Adjust the position of the
follower crank position.
∘ Adjust intermeshing pressure
between the driving knife and
the fixed knife.
∘ Adjust the position of the driving
knife.
∘ Adjust synchronizer.
∘ Adjust the thread trimmer cam
p28 - ꊳ
p27 - ꊱ
p27 - ꊲ
p30 - ꋀ
p29 - ꊶ
After thread
trimming,
needle thread
slips out of
needle
① Needle thread tension disc fails to open
② Thread catches in thread retainer.
③ Thread is not smoothly passed through
thread handling parts.
④ Needle thread tension releasing timing
is too delayed.
∘ Adjust the thread release lever.
∘ Check route the upper thread.
∘ Make smoothing thread handing
parts.
p29 - ꊾ
p14 - ꊳ
After trimming,
needle thread is
too long ① Pretension is insufficient.
② Needle thread tension releasing timing
is too advanced.
∘ Increase spring pressure.
p14 - ꊳ
After trimming,
needle thread is
too short
① Working stroke of stack thread take-up
spring is too large.
② Thread is not smoothly passed through
thread handling parts.
③ Opening degree of needle thread
tension disc is insufficient.
④ Thread is caught in thread retainer.
⑤ Pretension is too high.
⑥ Thread is broken by the driving knife
and bobbin thread retaining spring.
⑦ Needle thread tension releasing timing
is improper.
∘ Reduce working stroke to the
degree that sewing performance
is not adversely affected.
∘ Polish thread handling parts.
∘ Adjust needle thread tension
releasing.
∘ How to route the upper thread.
∘ Decrease pretension.
∘ Buff end of bobbin thread
retaining spring.
∘ Adjust needle thread tension
regulator.
p14 - ꊳ
Stitches skip at
start of sewing
① Bobbin thread is out of bobbin thread
retaining spring.
② After thread trimming, needle thread is
too short.
③ Bobbin thread tension is too high.
④ Thread is wound 1 turn around needle. ∘ Correct spring pressure and also
the driving knife contact surface.
p18 - ꊺ ꋃ
p17 - ꋁ
p17 - ꋂ