JUKI LH-4128-7, Руководство инженера

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(1) How to remove the timing belt
1) Remove the window plate, two screws , and idler .
2) Remove the hand wheel and pulley cover .
3) Loosen the setscrew of the coupling . (The first screw is fastened flat.)
4) Turn the four screws and remove the motor .
5) Tilt the sewing machine and remove the oil tank .
For disassembly procedures, remove the four pipe stops and draw out the pipe. Then, pull out the lubricating
tube and remove three screws . Making sure not to damage the oil quantity indicator bar of the float asm.,
remove the oil tank .
6) Remove the hinge screw and the reverse feed solenoid lever , and dislodge the reverse feed arm. .
Then remove two screws and reverse feed solenoid .
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 and then install the motor . Fasten the first screw of the coupling to
the flat section of the upper shaft and tighten the second screw.
2) Mount the pulley cover and fasten the first screw of the hand wheel to the motor shaft in a flat posture.
Then tighten the second screw.
3) Confirm that the timing belt is meshed with the upper sprocket at the lower dead point of the needle bar.
After this confirmation, hook the timing belt on the lower sprocket . At that time, confirm that the engraved
marker line of the lower sprocket is positioned in parallel to the upper plane of the bed and that the first screw
of the lower sprocket is positioned on the worker side. (Refer to 5.-(6) Relation between the main shaft and
the lower shaft.)
4) Hook the feed adjust spring and mount the reverse feed solenoid . Since then, mount the reverse feed
solenoid lever and the reverse feed arm . (Refer to 5.-(14) and (15).)
5) Install the oil tank . At that time, be careful not to damage the oil quantity indicator bar of the float asm.
6) Install idler .
Adjust the fixing position of idler with two screws so that the belt tension becomes 80 to 90N at the lower
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 2) Width: 15mm 3) Span: 224mm
In regard to the usage of tension gauge, refer to the Instruction Manual for the tension gauge.