Adjusting The Rear Needle Guard; Relation Between The Rocking Thread Take-Up Timing And The Needle Thread Loop; Adjustment By The Crank - JUKI MF-7923 Instruction Manual

8. adjusting the rear needle guard

WarNING :
to protect against possible personal injury due to abrupt start of the machine, be sure to start the fol-
lowing work after turning the power off and ascertaining that the motor is at rest.
a
1
B
2
2

9. relation between the rocking thread take-up timing and the needle thread loop

WarNING :
to protect against possible personal injury due to abrupt start of the machine, be sure to start the fol-
lowing work after turning the power off and ascertaining that the motor is at rest.
In the case sttch skppng or thread breakage occurs because the needle thread loop s too large or too small,
change the needle thread feedng tmng of the rockng thread take-up to adjust the sze of the needle thread loop.

(1) adjustment by the crank

2
1. When screw 1 is loosened, the rocking thread take-up rotates due to the light weight. So, be careful. If 1. When screw
it rotates, refer to the item
2. Do not change the timing other than the aforementioned one since the sewing trouble will be caused.
3
4
4
3
8 mm
1
"^-3.�d�usting the rocking thread take-up" p.��. �d�usting the rocking thread take-up" p.��.
Adjust the lateral poston of rear needle guard 1 so
that t receves the needle wthn the range of B when
the needle s n ts lowest poston.
) Adjust the heght wth setscrew 2 so that the
dstance from edge lne a of rear needle guard 1
to the top end of rght-hand needle s .5 to 2 mm
when the top end 3 of the looper comes from the
extreme rght end to the center of rght-hand needle.
2) Make rear needle guard 1 slghtly come n contact
wth the rght-hand needle so that the clearance
between rght-hand needle and top end 3 of the
looper s 0 to 0.05 mm when top end 3 of the looper
comes from the extreme rght end to the center of
rght-hand needle.
In addton, make rear needle guard 1 slghtly come
n contact wth the medum needle so that the clear-
ance between the medum needle and top end 3 of
the looper keeps 0 to 0.05 mm when top end 3 of
the looper comes to the center of medum needle.
Perform the adjustment wth setscrews 2 and 4 .
) Loosen screw 1 .
2) Move 2 forward or backward. The relaton between
the movng drecton and the sze of needle thread
loop s as shown n the table below.
3) After the adjustment, securely tghten screw 1 .
* Clearance between crank 2 and thrust collar 3 has
been factory-adjusted to 8 mm at the tme of delv-
ery. (Engraved marker lne on rockng thread take-
up shaft 4 algns wth the edge of crank 2 .
¡Sze of needle thread loop
Move forward
Loop becomes smaller. Loop becomes larger.
– 9 –
Move backward