The bobbin case opener is timed correctly if the bobbin case opener eccentric is at its extreme
left position
when
the
needle bar has passed
the
lowest
point of its stroke
and
risen . or
1.8 mm. When the eccentric is at this position, the clearance gap between the opener finger
and
the
wall
of
the
position
slot
is
widest.
To make sure the mechanical opener has been timed correctly, check to see that the opener
finger
contacts
the
projection on
the
bobbin
case
and
begins
to rotate it
when
the hook
has cast off the loop and its point has reached a position
about
midway between the right
and
top
positions,
i.e.
at
northeast.
Since
the
motion of
the
opener
finger is very
slow
and
hardly perceptible, we recommend
that you push the bobbin case over to the right at the bottom and place a thin piece of paper
between the finger and the projection on the bobbin case. When the finger begins to hold
the
paper
in place, it has reached
the
position at which it will normally begin to rotate
the
bobbin
case.
In adjusting
the
mechanical opener, care
should
be taken
that
there is a clearance of .03",
or 0.8 mm, between the opener finger and the face of the bobbin case (Fig. 30), and of .012",
or 0.3 mm,
between
the
opener
finger and
the
wall of the position slot (Fig.
31).
Fig.
30
Fig. 31
25.
Dismantling
the
Link
Take-up
There are
two
procedures
that
may be followed;
In
the
first,
take-up
link
Lis
left
inthe
machine
and is
disconnected
from
take-up
lever
F by
turning out screw z (Fig. 34). Swing the take-up lever up, and the link down, as shown in
Fig. 32. Pull the
take-up
lever
through
the
slot
and
out of
the
machine.
34
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