Needle Selection Mechanism - Brother Model KH--830 Service Manual

KH- 830 NEEDLE SELECTION MECHANISM
Fig. A
Fig.
B
-6-
.
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• In the
IQf- 830
needle selection mechanism, when the needle is
moved downward by the needle selector c. a m attached t o the car-
rbge, the card reader
in
the position of open hole In the punched
card moves up. When the card reader moves up. the card reader
is
forced to the left by the rotary cam, thus caus.lng the cii'C! ligna!
lever {which is coupled to the card reader) to
mo~e.
Thus,
the
card sipal lever causes the needle selector plate to the
rigltt,
and
the needle shunk is caught by the book of the needle selector
plate. This keeps the needle forced down, and the needle is led to
the D position by the separation cam.
On
the needle which Is not positioned
in an
open hole, the card
reader does not move up, and u a result, the needle cannot be
held down (in other words, it n>tums to the home position even if
held down}, it is pushed back to the B position by the separation
earn attached to the carriage.
MaiP
body
I)
If
there
Is
an open hole,
the
card reader ia.moved up by
the
spring.
2) The card reader is moved
to the
left by the needle selector cam.
3) The signal lever is moved to the
left by the card
reader.
4) The signal lever pivots upon A (see Fig. A), and the needle
selector plate moves to
the
right.
5) The needle selector plate in this position is moved to the right
until it catches the needle shunk, thus keeping the needle forced
down .
6) When there is no hole, the needle selector plate does not move,
and as a result, the needie returns to the home position from
where It is held down.
eama.
Since the needle positioned
in
an open hole
lJ
under the needle
selector plate, it is carried to the D position through the separa-
tion earn.
The
needle which is
not
positioned in
an open hole
is immediate·
ly
forced b:u:k to the home position from the pocltlon where it is
held, it operates at A (see Fig. B) and forced back to B.