Adjusting The Bobbin Thread Tension; Installation Of Bobbin Case - JUKI LBH-1790 Instruction Manual

5. Adjusting the bobbin thread tension
Adjust the bobbn thread tenson as gven below when the bobbn thread s pulled up at the poston where
thread slt 1 of bobbn case comes up.
Purl sttch
Whp sttch
Turnng tenson adjust screw 2 clockwse wll ncrease bobbn thread tenson, and turnng t
counterclockwse wll decrease the tenson.
Adjust the bobbin thread tension to lower for synthetic filament thread, and to higher for spun thread.
The thread tenson s hgher by approxmately 0.05N when the bobbn case s set to the hook snce dle-
preventon sprng s provded.
When bobbin thread tension is adjusted, check the needle thread tension setting of
the memory switch. (See P.44.)
6. Installation of bobbin case
WARNING :
To protect against possible personal injury due to abrupt start of the machine, be sure to start the
following work after turning the power off and ascertaining that the motor is at rest.
1
To such an extent that bobbn case quetly comes down when
0.05 to 0.5N holdng thread end comng from bobbn case and shakng t quetly
up and down.
To such an extent that bobbn case barely comes down when
0.5 to 0.3N holdng thread end comng from bobbn case and shakng t
somewhat strongly.
– 4 –
2
1
) Lft up and hold bobbn case latch lever between
two fingers.
2) Push the bobbn case nto the hook so that t s
supported by the hook shaft 1 and then snap n
the latch lever.
Press the bobbn case untl the predetermned
poston s reached, and t wll clck.
1. If the bobbin case is out of the
predetermined position, it can jump
out from the hook to cause the
needle thread to tangle on the hook
shaft. Check to be sure that the
bobbin case is properly installed in
the correct position.
2. There is a difference in the shape of
bobbin case between the standard
hook and the dry one. They have
nothing in common with each other.