JUKI LH-4128-7 Engineer's Manual page 67

(1) How to remove the timing belt
1) Remove the window plate, two screws
2) Remove the hand wheel
3) Loosen the setscrew
4) Turn the four screws
5) Tilt the sewing machine and remove the oil tank
For disassembly procedures, remove the four pipe stops
tube and remove three screws
remove the oil tank
6) Remove the hinge screw
Then remove two screws
7) Remove the feed adjust spring
Remove the knee patch plate and tilt the sewing machine.
8) Draw out the timing belt
(2) How to install the timing belt
1) Apply a belt to the upper sprocket
the flat section of the upper shaft and tighten the second screw.
2) Mount the pulley cover
Then tighten the second screw.
3) Confirm that the timing belt
After this confirmation, hook the timing belt
marker line of the lower sprocket
of the lower sprocket
the lower shaft.)
4) Hook the feed adjust spring
solenoid lever and the reverse feed arm
5) Install the oil tank
6) Install idler .
Adjust the fixing position of idler
dead point of the needle bar. (See descriptions below about tension gauge setup.)
(Caution) When you have set up the timing belt tension, make readjustments, without fail, in regard to
5-(9)-1) Needle-up stop position of the sewing machine, 5-(2) Timing between the needle and
the hook, and 5-(12)-4) Position of the thread trimming cam and the thread trimming timing.
Try to operate the reverse feed lever at the maximum pitch and confirm that there is no interference between the
feed control base (butterfly type) and idler
7) Install the window plate.
Cautions for belt tension adjustments:
• Measure the front section of the belt.
• Distance between microphone and belt shall be 1cm.
• When idler is adjusted, rotate the hand wheel by two turns, without fail, so that the belt can be well attached
to.
* Initial setup value of the belt tension gauge (U-507) / Unit belt: 575-5GT-15
1) Mass: 4g/m
In regard to the usage of tension gauge, refer to the Instruction Manual for the tension gauge.
, and idler
and pulley cover
of the coupling . (The first screw is fastened flat.)
and remove the motor
. Making sure not to damage the oil quantity indicator bar of the float asm.,
.
and the reverse feed solenoid lever
and reverse feed solenoid
.
.
and then install the motor
and fasten the first screw of the hand wheel
is meshed with the upper sprocket
is positioned in parallel to the upper plane of the bed and that the first screw
is positioned on the worker side. (Refer to 5.-(6) Relation between the main shaft and
and mount the reverse feed solenoid
. At that time, be careful not to damage the oil quantity indicator bar of the float asm.
with two screws
2) Width: 15mm
.
.
.
.
and draw out the pipe. Then, pull out the lubricating
, and dislodge the reverse feed arm.
.
. Fasten the first screw of the coupling
on the lower sprocket
. (Refer to 5.-(14) and (15).)
so that the belt tension becomes 80 to 90N at the lower
.
3) Span: 224mm
– 63 –
to the motor shaft in a flat posture.
at the lower dead point of the needle bar.
. At that time, confirm that the engraved
. Since then, mount the reverse feed
.
to