JUKI LK-1900AN Engineer's Manual page 33

1. Apply a proper amount of grease (JUKI Grease A) to the grooved cam block of the cam 1 , the pe-
ripheral cam block, and the rollers of the presser bar lifter link 8 and the thread trimmer link 9 . Refer
to "9.-(4) Parts to which grease is applied."
2. While the cam 1 is being inserted in the shaft of the presser lifting motor 6 , mount the assembly
on the sewing machine frame and tighten the four set screws 5 . The insertion of the cam should be
done gently in order not to hurt the bearing 7 .
3. Clearance B toward the presser bar lifter link 8 and Clearance A toward the thread trimmer link 9
should be equally distributed. For this purpose, adjust the position of the cam 1 and fix it with the use
of the two set screws 2 . (Apply the screws to the flat section at both ends of the shaft.)
* If it is difficult to examine Clearance B, Clearance A should be adjusted to 0.5 to 0.7 mm during as-
sembly.
4. Mount the sensor slit 3 with the two set screws 4 so that the end plane of the motor shaft can ap-
proximately coincide with that of the sensor slit 3 . (Join the flat section for installation.)
* Confirm that the slit plate of the sensor slit 3 does not interfere with the presser bar lifter sensor.
5. Refer to "(13) Thread trimmer and presser foot origin sensor adjustment" and make sensor adjust-
ments.
Adjustment procedures
1. Start the test mode CP-6.
2. Tread on the pedal for the retrieval of the thread trimmer and
presser bar lifter (cam) origin.
3. Using a bar (2.5 mm hexagonal wrench key corresponding)
4 or the like, confirm that the standard holes A and B of the
sewing machine frame coincide with the standard hole C of the
thread trimmer and presser bar lifter cam 1 .
4. If the standard hole C of the thread trimmer and presser bar
lifter cam 1 stays in the upper E direction, loosen the set
screw 2 to move the sensor mounting plate 3 in the lower D
direction and then fix it. If the standard hole C of the thread
trimmer and presser bar lifter cam 1 stays in the lower D
direction, loosen the set screw 2 to move the sensor mounting
plate 3 in the upper E direction and then fix it. After the sen-
sor mounting plate 3 has been fixed, push the start switch for
the retrieval of the thread trimmer and presser bar lifter (cam)
origin to confirm whether the standard holes coincide with each
other.
5. Repeat the above steps 2. to 4. until the coincidence is con-
firmed.
(Caution) Confirm that there is no mutual interference be-
tween the sensor slit plate 5 and the sensor before
tightening the set screw 2 .
Procedures of assembling
– 21 –
Results of Improper adjustment
If there is no coincidence of the
o
standard holes, such a condition
is regarded as a thread trimmer
timing error. This can be a cause
of trouble in thread trimmer or
unthreading at the beginning of
sewing.