Timing Of Needle And Rotary Hook; (Clearance Between The Needle And The Rotary Hook Point) - promelectroavtomat ULT2003D Service Manual

5. TIMING OF NEEDLE AND ROTARY HOOK (CLEARANCE BETWEEN THE
NEEDLE AND THE ROTARY HOOK POINT)
STANDARD
When test mode "5" is selected and the needle is raised 2.9-3.3 mm from its lowest position, the rotary hook
point should be positioned at the right side of the needle.
The clearance between the needle and the rotary hook point should be 0.1 mm or less, and they should never
touch each other.
ADJUSTMENT
1. Select test mode "5".
2. Loosen the three screws of the lower shaft gear.
3. Adjust timing of the needle and the rotary hook. (When the needle is raised 2.9-3.3 mm from its lowest
position, the rotary hook point should be positioned at the right side of the needle.)
4. Tighten the three screws of the lower shaft gear.
5. Turn the eccentric screw, and set the clearance between the needle and the rotary hook point to 0.1 mm or
less. Make sure that the needle does not make contact with the rotary hook point.
Adjustment Points
1. When adjusting the timing, the needle should be at its lowest and leftmost position.
3. If the needle rises too little, skipped stitches, split thread or cut thread may occur. (Refer to (B) page 35.)
If the needle rises too much, skipped stitches, split thread or cut thread may occur due to a loop forming in
the thread. (Refer to (C) page 35.)
5. If the clearance is too large, skipped stitches may occur. (Refer to (D) page 35.)
If the clearance is too small, the needle may generate an irregular noise (scraping metal sound) or the
needle may break.
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