JUKI LU-2800 Series Engineer's Manual page 37

Adjustment procedures
3) Alternate momentum
1. Set the stitch dial to "0".
2. Turn the handwheel to make sure that the amount of alternate
vertical movement of walking foot ❶ and presser foot ❷ is
almost equal.
3. When the amount of alternate vertical movement is not equal,
remove the rubber plug ❸ on the rear face of machine arm.
Loosen clamping screw ❹ of the top feed rear arm to adjust so
that the amount of alternate vertical movement can be unified.
Adjust the amount almost to A = B.
When the amount of alternate vertical movement of the walking
o
foot is larger than that of the presser foot :
Loosen clamping screw ❹ of the top feed rear arm in the state
1)
that walking foot ❶ is raised a little, press walking foot ❶
against the feed dog.
Re-tighten clamping screw ❹ of the top feed rear arm and turn
2)
the handwheel to make sure of the amount of alternate vertical
movement.
4) Top feed cam timing
1. Set the stitch dial to "6".
2. Set the alternate vertical dial to "3".
3. Loosen setscrews of the top cover to remove the top cover.
Loosen two setscrews ❺ of the top feed cam.
4.
Turn the top feed cam  so that the needle ❻ , the throat plate
5.
❼ , the walking foot ❽ and the feed dog ❾ are in the position
written on the left page.
Tighten two setscrews ❺ of the top feed cam.
6.
7. Attach the top cover.
(Standard) In case of model group Z, When four points of top
end of the needle ❻ , top surface of the throat plate
❼ , under surface of walking foot ❽ and top surface
of feed dog ❾ are aligned with one another, the
setscrew No. 2 of the top feed cam  is visible from
the position between the alternate vertical change
base and the machine frame.
Results of Improper adjustment
Adjust the amount of alternate verti-
cal movement of the walking foot ❶
so that it is larger than that of the
presser foot ❷ in accordance with
the sewing products.
Sewing sponge material or the
o
like
Sewing material with overlapped
o
sections
When the amount of alternate ver-
tical movement of the walking foot
❶ and presser foot ❷ are consid-
erably different :
The stitch pitch is different from
o
the value set by the dial.
Decrease the number of revolu-
o
tion of the motor a little since the
feed efficiency is decreased.
Pitch error at high or low speed
o
is apt to occur.
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