JUKI MF-7800D Series Engineer's Manual page 105

Adjustment Procedure
6. Initial position of the lower thread trimmer mechanism
Adjust so that the right-hand edge of lower knife holder
with the right-hand edge of thread trimmer installing base
air cylinder moves to the extreme left position.
(1) Remove pin screw
(2) When turning the screw section of adjustment link
lower knife holder
counterclockwise, lower knife holder
(3) Install pin screw
holder .
7. Adjusting the stopper
Adjust the clearance between knife base
air cylinder moves to the extreme left position.
(1) Loosen setscrew
and stopper to 6 to 7 mm.
(2) After the adjustment, tighten setscrew
(3) When the clearance is made larger, thread remaining length at the
end of sewing is shortened, and the clearance is made smaller,
thread remaining length at the end of sewing is lengthened.
8. Adjusting the height of the lower knife
Adjust the clearance between looper
(1) Bring the needle bar to its highest position.
(2) When actuating air cylinder
protrudes in the loft-hand direction.
(3) Loosen setscrews
down so that the clearance between the bottom surface of lower
knife and the top surface of looper
(4) After the adjustment, tighten setscrews
by hand, and make sure that the thread trimmer device smoothly
moves.
(Caution) Perform the work with the needle bar at the highest
position when actuating the thread trimmer mechanism
by hand.
.
moves to the left and when turning
moves to the right.
and make sure of the position of lower knife
and adjust the clearance between knife base
.
and lower knife
in the right-hand direction, lower knife
in guide and move the lower knife up or
is 0 to 0.1 mm.
, actuate air cylinder
aligns
when
clockwise,
and stopper when
.
– 101 –
Results of Improper Adjustment
UT25