Locus And Longitudinal Motion Of The Looper - JUKI MF-7900 Series Engineer's Manual

(11) Locus and longitudinal motion of the looper

WARNING :
Turn OFF the power before starting the work so as to prevent accidents caused by abrupt start of the
sewing machine.
1. It is the standard that the top end of left needle
touches the position of 1/4 to 1/3 from the
bottom face of the back of the looper when the
looper returns from the extreme left position in
the standard looper motion locus.
❶
2. Longitudinal motion timing of the looper
(1) The standard position of the cam is the po-
sition where the engraved marker line G on
looper longitudinal motion eccentric cam ❺ is
adjusted to the center of notches H on looper
driving shaft.
(2) It is the standard motion locus of the looper
that the top end of looper lightly comes in con-
tact with right needle and middle needle, and
passes left needle with a clearance of 0.05 to
0.1 mm when the rear needle guard does not
work.
0.05 to 0.1 mm
Standard adjustment
– 26 –
1/4 to 1/3
F
E
G
H