JUKI LU-1510N Engineer's Manual page 47

Adjustment Procedures
4) Adjusting the knife pressure
1. Loosen setscrews 1 in the moving knife.
2. Adjust the installing position of the moving knife so that the
position where moving knife 2 and counter Knife 3 start
coming in contact with each other starts at the position of 6 to
7 mm from the top end of the moving knife. At this time, if
moving knife 2 comes in contact with the clamp spring, the
knife pressure is increased by the clamp pressure. So, adjust
the knife pressure in the state that the clamp pressure is not
applied to the knife.
3. Tighten setscrews 1 in the moving knife.
(Caution) Operate the sewing machine with the knife pressure
minimized to such an extent that both needle and bobbin
threads can be trimmed.
1. Loosen setscrew 6 in the rocking arm.
2. Adjust so that the distance between the top end of the counter
knife 3 and the top end of the moving knife is 2±0.2 mm when
moving knife 2 travels to its back end.
3. Tighten setscrew 6 in the rocking arm so that there is no thrust
play at the moving knife shaft.
4. In case of 2-needle, both the left and right are the same
adjustment value.
(Check) At this time, check that rocking arm 4 comes in close
contact with thread trimmer stopper plate 5.
5) Thread trimmer cam
1. Loosen setscrews 1 in the thread trimmer shaft connecting
plate.
2. Adjust the clearance between thread trimmer driving plate 2
and cam roller A 3 to 0.1 to 0.2 mm.
3. Make the edge of thread trimmer cam 4 come in close contact
with cam roller B 5, and temporarily tighten setscrews 6 in
the thread trimmer cam.
4. Make safety clutch disk 7 come in close contact with thread
trimmer cam 4, and securely tighten setscrew 8 in the safety
clutch disk.
5. Tighten setscrews 1 in the thread trimmer shaft connecting
plate. (For connecting procedure, refer to "7) Connecting the
rocking arm and the thread trimmer roller arm".
(Caution) Install the thread trimmer cam in the state that
thread trimmer driving plate 2 comes in close contact with
the follower installing base.
Results of Improper Adjustment
When the knife pressure is high
™ Blade sections of the counter
knife and the moving knife may
be damaged.
™ Torque at the time of thread
trimming is increased resulting
in motor-stop.
™ Defective thread trimming
operation will result.
When the knife pressure is low
™ Defective thread trimming will
result.
When there is no clearance
between the cam roller and the
driving plate
™ Thread trimmer cam interferes
with the cam roller resulting in
breakage or machine lock.
When the clearance between the
cam roller and the driving plate is
large
™ C a m r o l l e r e n t e r s d u r i n g
operation resulting in machine
rock.
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