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29
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Adjustment Procedures
Results of Improper Adjustment
1. When the thread grasping force of the needle thread trimmer
has reduced, slightly bend the top end of the thread presser
spring so that it comes in contact with the thread trimming
blade of the upper knife over the length with no clearance
and so that the needle thread trimmer securely holds the
thread regardless of the position of the thread trimming blade
at which the thread is trimmed.
2. When the needle thread trimmer fails to cut the thread sharp,
grind the thread trimming blades at the top end of the upper
and lower knives with an oil-stone.
Move forward the feed mechanism and adjust so that the needle
thread trimmer lever comes in light contact by 1 mm with the
slope of the needle thread trimmer driving cam when the needle
thread trimmer locking bracket latch engages by 0 to 0.5 mm
with the needle thread trimmer arm (rear).
(Caution) When sewing the thick materials or overlapped
section, set the sewing material to the machine,
use the forward key and confirm that the needle
thread trimmer knife does not move to this side
at the start of sewing. In the case where the needle
thread trimmer moves to this side, perform again
the aforementioned adjustment while the sewing
material is set to the machine.
In case of type A, refer to the item “(16) Adjusting the needle
thread trimmer control lever (P.20)” as well.
™
If the pressure of the thread presser
spring is low, slip-off of thread at the
start of sewing will occur.
If the needle thread trimmer lever does
not come in contact with the slope of
the needle thread trimmer driving cam
when the needle thread trimmer arm
(rear) comes off the needle thread
trimmer locking bracket latch, opening
of trimmer will be deteriorated.
(Caution) If the driving arm comes
in strong contact with the cam,
the needle thread trimmer moves
to this side at the start of sewing
and comes in contact with the
needle. As a result, needle
b r e a k a g e m a y o c c u r .
(Particularly, in case of B and C
types)
Summary of Contents for LBH-1700
Page 1: ...R ENGINEER S MANUAL 29339504 No 04 Electronic Buttonholing Machine LBH 1700 Series ...
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