15
stitch. When the bender bar is stopped against the
work material, the driver bar continues downward
to exert pressure on the crown of the stitch, driving
it through the work material.
If the end of the driver bar is chipped it allows the
legs of the stitch to back up into the broken area.
This causes the corner of the crown to fracture or a
"spike" section to protrude above the crown. A
chipped driver bar is usually the result of driving a
stitch on top of another stitch. A worn driver often
causes deformed stitches or fracturing at the corners
of the crown.
G. Bender Bar Latch
The bender bar latch opens and closes the grip and
is actuated by the grip release slide and driver bar.
If the contact points of the latch become worn, tim-
F
ing of the grip is erratic and uneven wire feed re-
sults. A dirty latch will decrease preassure of the
grip on the wire. This causes wire slippage. Clean
or replace the latch.
H. Grip, Grip Release Slide and
Face Plate: (Figure 14)
The
grip spring (Index A) exerts pressure on the
benderbar latch (Index B) to close the grip (Index
C) at the start of the down stroke. The grip release
slide (Index D) actuates the bender bar latch at
point X to open the grip after the correct amount of
wire has been fed to make a stitch. The serrated
teeth on the grip must be sharp or slippage will
occur, producing uneven wire draw.
B
C
D
E
X
A
Figure 14
(CTTT2605 Scene 15)