Brother RH-9820, Service Manual

Page: 176 / 236

7. ADJUSTMENTS
RH-9820
167
7-24-2. Adjusting the upper movable knife
The upper movable knife (1) is adjusted so that only the upper thread that is in front of looper L (2) is cut. If two of the upper
thread loops (front and back) are cut, the upper thread trailing length will become too short and skipped stitches may occur at
the sewing start.
* If this adjustment is carried out in manual mode, the upper thread trimming operation can be checked step by step, which
will make adjustment easier.
1. Turn the upper shaft pulley to set the needle to the lowest
position at the outside sewing position.
2. Loosen the screw (3), and then adjust the gap <a>
between the tip of the upper movable knife (1) and the
needle to 0.1 - 0.4 mm.
3. Turn the upper shaft pulley to set the needle to its highest
position (needle up stop position) at the outside sewing
position.
4. Loosen the screw (4), and then adjust the position of the
upper movable knife (1) so that it is in between the throat
plate (5) and spreader L (6) without touching either of
them.
5. Move the upper movable knife (1) sideways by hand and
check that it does not touch either the throat plate (5) or
spreader L (6).
6. Once adjustment is complete, tighten the screws (4) and
(3) in that order.
NOTE: Upper thread trimming timing
<-00 and -01 specifications>
When the upper movable knife (1) has returned to its original
position, the upper thread is trimmed at position A.
<-02 specifications>
When the upper movable knife (1) starts moving, the upper
thread is trimmed at position B.
<-00 and -01 specifications> <-02 specifications>
0403B
(Viewed from directly to the right)
0565B