Brother International EF4-B561 Service Manual - Page 20

2

UNDER

LOOPER

MECHANISM

C2)

Procedures

Q'ty

of

screw

1

Remove

needles

and

needle

plate.

2

Temporarily

fasten

under

looper

holder

0

on

under

1

looper

lever

shaft

0.

3

Insert

under

looper

Q

all

the

way

into

under

looper

holder

0.

4

Measure

under

looper

0

tilt

at

its

point

and

bottom,

adjust

it

until

the

measurement

difference

is

in

the

range

of

1

to

1.5

mm,

and

then

fasten

under

looper

with

screw

0.

5

Install

the

standard

needle

for

adjustment

into

needle

clamp.

EN

The

below

items

of

et

and

0

should

be

taken

simultaneously.

6

In

case

of

sewing

machines

made

to

the

standard

specifications,

adjust

the

distance

between

the

under

looper

point

and

the

needle

center

to

4.5mm

when

the

under

looper

is

at

the

left

most

position.

The

sewing

machine

of

the

high

-lift

specifications

must

be

adjusted

to

a

distance

of

2.2mm

between

them.

(Sidewise

positioning)

S

afety

Stitch

In

case

of

standard

specifications,

that

distance

is

4.7mm.

In

case

of

high

-lift

specifications,

that

distance

is

2.2mm.

7

With

the

point

of

under

looper

in

line

with

the

center

of

needle,

make

an

adjustment

so

that

the

point

of

under

looper

will

push

needle

0.01

-

0.05mm

(i.e.,

slightly

contact

needle)

in

the

upward

travel

of

needle.

However,

in

case

of

sewing

for

thick

materials,

must

be

adjusted

to

touch

about

0

to

0.05mm

between

them.

(Longitudinal

positioning)

*

0.05

to

0.07mm

for

cotton

fabrics;

0.08

to

0.1mm

for

chemical

fabrics.

Twin

Needles

1

Install

the

right

needle

into

needle

clamp,

loosen

screw

for

needle

bar

clamp,

turn

the

needle

bar

until

the

under

looper

point

hits

both

needles

by

approximately

the

same

depth

or

the

right

needle

slightly

deeper,

and

then

retighten

screw

for

needle

bar

clamp.

Also

check

the

height

of

needle

bar

at

the

same

time.

(See

the

figure

at

right.)

—

18

—

I

—

I

.5mm

/A

Scale

0.01

—

0.05mm

slightly

contact

needle

0.2-0.3mm

Brother International EF4-B561 Service Manual - Page 20

-0.3mm

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