21
990D
Lower looper
0.2 ~ 1.2 mm
Upper looper
(Fig. 1)
(Fig. 3)
(Fig. 4)
(Fig. 2)
Direction B
Direction A
Marking-off line
Upper looper drive cam
Setscrews
Correct Setting:
When the lower looper moves to the right, the tip of upper looper meets the lower looper within 0.2
to 1.2 mm from the left of lower looper eye as shown in Fig.1.
To adjust:
1. Before proceeding with this adjustment, check the lower looper timing and the position of the
upper looper.
2. Remove the machine base.
3. Loosen two setscrews, and adjust the timing by turning the upper looper drive cam in the
direction of:
A: If the timing of the upper looper is advanced as shown in Fig. 3.
B: If the timing of upper looper is delayed as shown in Fig.4.
The allowance is 0.2 to 1.2 mm from the left edge of the lower looper eye as shown in Fig. 1.
4. Tighten two setscrews.
5. Check the clearance between the loopers.
6. Attach the machine base.
TO ADJUST THE TIMING OF THE UPPER AND LOWER LOOPERS
