JUKI MF-7800D Series, Engineer'S Manual

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9. Adjusting the longitudinal position of the blade point of lower
knife
(1) Bring the needle bar to its highest position.
(2) Adjust so that the blade point of lower knife is in the center of the
thickness of looper when the clearance between the right-hand
edge of looper and the blade point of lower knife is 12 mm.
(3) Loosen nut , move lower knife holder to and fro, and adjust the
position of the blade point of lower knife .
(4) After the adjustment, tighten nut .
10. Adjusting the lower knife holder guide
(1) Bring the needle bar to its highest position.
(2) Loosen screw and adjust so that lower knife holder lightly
comes in contact with guide when lower knife moves from the
fight to the left.
(3) After the adjustment, tighten screw , actuate air cylinder 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.
11. Adjusting the thread trimmer sensor
The safety switch is installed so that the sewing machine does not
start unless the lower thread trimmer device returns to its home
position.
(1) Loosen setscrews .
(2) Adjust switch plate so that LED of thread trimmer sensor lights
up in the state that the thread trimmer device is fully returned to its
home position.
(3) Tighten setscrews .
(Caution) Perform the work with the needle bar at the highest
position when actuating the thread trimmer mechanism
by hand.
Adjustment Procedure
Results of Improper Adjustment
UT25