JUKI MF-7500 Series, Instruction Manual

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10. Relation between the rocking thread take-up timing and the needle thread loop
❸
❹
❷
❶
WARNING :
To protect against possible personal injury due to abrupt start of the machine, be sure to start the follow-
ing work after turning the power off and ascertaining that the motor is at rest.
8 mm
In the case stitch skipping or thread breakage occurs because the needle thread loop is too large or too small, change
the needle thread feeding timing of the rocking thread take-up to adjust the size of the needle thread loop.
1) Loosen screw
❶
.
2) Move ❷ forward or backward. The relation between the
moving direction and the size of needle thread loop is
as shown in the table below.
3) After the adjustment, securely tighten screw
❶
.
* Clearance between crank ❷ and thrust collar ❸ has
been factory-adjusted to 8 mm at the time of delivery.
(Engraved marker line on rocking thread take-up shaft
❹
aligns with the edge of crank
❷
.)
◦ Size of needle thread loop
1. When screw ❶ is loosened, the rocking thread take-up rotates due to the light weight. So, be care-
ful. If it rotates, refer to the item “ Ⅵ -3. Adjusting the rocking thread take-up”
(See page 16.)
.
2. Do not change the timing other than the aforementioned one since the sewing trouble will be caused.
Move forward Move backward
Loop becomes smaller. Loop becomes larger.
(2) Adjustment by the eccentric cam
1) Remove the top cover.
2
） Loosen screw ❶ .
3) Turn the eccentric cam. The direction of turning the ec -
centric cam and the relation between the eccentric cam
and the needle thread loop is shown in the following
table.
4) After the adjustment, fully tighten screw ❶ .
* With the factory-adjusted value at the time of shipment,
the marker lines are aligned.
◦
Size of needle thread loop
A Move forward B Move backward
Loop becomes smaller Loop becomes larger
(1) Adjustment by means of the crank
❶
⇧
⇩
B
A
Marker lines
Eccentric cam