JUKI HZL-F series, Service Manual

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5-4 Timing belt

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 Remove the front panel and the microcomputer PCB.

     Adjustment procedure
 

. Loosen the setscrew in the idler mounting base and loosen the timing belt.

  2. Turn the hand wheel to bring the needle bar to its lowest dead point.

3. Turn the hook driving shaft to bring the feed dog to its lowest dead point.

4. Carefully keeping the condition described in steps 2 and 3, set the timing belt on the hook driving shaft  

    pulley (by temporarily tightening the setscrew in the idler mounting base) so that the setscrew No. 2 in the  

    pulley is brought to just underside of the pulley. 

5. Applying .96±0.29 N force to the idler by means of a spring scale, securely tighten the setscrew.

Push the middle part of the screw  

with the spring scale.

Setscrew of the idler mounting base

The setscrew No. 2 is located just underside of the hook driving shaft pulley. 

5-5 Feed timing

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 After checking the feed dog height and the needle bar height, carry out adjustment of the feed timing.

     Adjustment procedure
 

. Assemble a HA x  needle #4 into the needle bar.

2. Loosen setscrew No. 2 in the hook driving shaft pulley.

3. Loosen setscrew No.  in the hook driving shaft pulley. Adjust the pulley so that the lower end of the 

    needle eye in the descending needle #4 is aligned with the top surface of the throat plate when the top 

    face of the descending feed dog is aligned with the top surface of the throat plate by turning the

    hand wheel toward you. After adjustment, tighten the setscrew No. 2.

4. Turn the main shaft by one revolution to confirm the timing.

The lower end of the needle eye in needle 

#14 aligns with or is 1 mm or less above 

the top surface of the throat plate. 

Top surface of the feed dog aligns 

with the top surface of the throat plate.

Setscrew No. 2

Setscrew No. 1

1.96 ± 0.29 N