Adjusting The Thread Trailing Length After Thread Trimming (B856E) - Brother LZ2-B855E Service Manual

6-17. Adjusting the thread trailing length after thread trimming (B856E)

e
r
5mm
r
5mm
2-4mm
e
Stronger
Weaker
r
u
e
e
Should not touch
Longer
Shorter
r
1032S
w
y
q
t
B
A
Seen from direction B
A
t
e
0.5mm
1033S
1034S
y
w
q
t
B
A
Seen from direction B
A
t
e
0.5mm
1033S
LZ2-B855E,B856E
<Standard position for upper thread feeding device>
The standard position for the upper thread feeding device
is as shown in the illustration.
1. Loosen the set screw q.
2. Turn the base w so that the end of the wire e is at a
position 5 mm below the position where the upper
thread r passes.
3. Tighten the set screw q.
* At this time, keep the end of the wire e 0.5 mm
away from surface A of the part where the thread
guide t is installed.
4. Loosen the two bolts y.
5. Move the wire e to the left or right so that the end of
the wire e is 2 to 4 mm from the top-left edge of the
thread guide t.
6. Tighten the bolts y.
<Adjusting the upper thread trailing amount>
The standard upper thread trailing amount after thread
trimming varies as shown below depending on the type
of thread used.
Upper thread
nylon 100D 1 X 3(Z)
#60 spun
If adjustment is necessary, adjust the position of the wire
e as described below.
1. Loosen the set screw q.
2. Turn the base w to adjust the vertical position of the
end of the wire e.
• To increase the upper thread trailing amount, raise
the position of the wire e without letting it touch
the upper thread r.
• To decrease the upper thread trailing amount, lower
the position of the wire e without letting it touch
the thread guide t.
3. After adjusting, tighten the set screw q.
* At this time, keep the end of the wire e 0.5 mm
away from surface A of the part where the thread
guide t is installed.
Note:
If the tension of the pre-tension y is to strong, it
will be more difficult to adjust the upper thread trail-
ing amount.
The pre-tension y should be adjusted to as weak a
tension as possible while still allowing the rotary
disc u to rotate smoothly.
* The thread tension will change at this time, so
be sure to re-adjust the upper thread tension.
(Refer to instruction manual page 123.)
6. ADJUSTMENTS
Upper thread trailing amount
50 - 60mm
40 - 50mm
6-14