Replacing The Bobbin Thread Trimmer; Open Timing And Open Amount - JUKI lbh-1790 series Engineer's Manual

4) Replacing the bobbin thread trimmer

5) Open timing and open amount

Conditions : Fix bobbin thread trimmer
working link 1 in the center
of the long hole.
Standard Adjustment
3
1
2
™ Thread holding position
Clearance between bobbin thread trimmer upper
knife pin 2 and bobbin thread working arm 3 is
0.5 to 1.5 mm.
™ Open amount at start of opening
Overlapping amount (arrow mark section) of the
1
top end of bobbin thread trimmer upper knife 4
and holding spring 5 is almost "0".
K21
sewing start Initial value : 8 (Memory switch level
2)
23
− −
2
3
Open amount of bobbin thread trimmer at
5
0
4