Brother DT4-B281 Service Manual

SERVICE

MANUAL

FOR

DT4-B281

FOUR NEEDLE DOUBLE CHAIN

STITCHER WITH

PULLER

•

Table

[A]

Model Plate Display ....................................................................................................................... 1

[B]

Specifications ................................................................................................................................. 2

[C]

Description of

[)

Needle bar

~

Looper

II]

Retainer

[!]

Feed

~

Presser foot lift

@]

Thread release

[1]

Looper thread take-up

ffi]

Puller

[2]

Lubrication ............................................................................................................................. 9

Mechanism

mechanism

mechanism

mechanism

mechanism

mechanism

............................................................................................................. 3

........................................................................................................... 3

................................................................................................................. 4

............................................................................................................... 5

.................................................................................................................... 6

mechanism

mechanism

mechanism

................................................................................................................... 8

of Contents

................................................................................................... 7

...................................................................................... ~-............. 7

......................................................................................... 8

[D] Disassembly Procedures .................................................................................................................

[!]

Cover ...................................................................................................................................... 1 0

11]

Presser ....................................................................................................................................

[1]

Feeding ..................................................................................................................................

(!]

Retainer ..................................................................................................................................

~

I...ooper

[§]

Needle bar ..............................................................................................................................

[1]

Upper

[E]

Assembly

ITJ

Upper

III

Needle bar ..............................................................................................................................

m Looper

@]

Retainer ..................................................................................................................................

[I]

Feeding ..................................................................................................................................

lEJ

Presser ....................................................................................................................................

[1]

Cover ......................................................................................................................................

[F]

How

to Change

[G]

Disassembly and Assembly

and

needle guard .......................................................................................................

and

lower shafts ..........................................................................................................

and

Adjustment Procedures ...........................................................................................

and

lower shafts ..........................................................................................................

and

needle guard .......................................................................................................

the

Roller ..............................................................................................................

of

the

Bottom

Metering Device ........................................................

10

11
11
12

12

13

13
14

14

15

17

19
20
21
23

24
27

--~-

---,

\

/-

.·\

[li]

Standard Adjustnlent ......................................................................................................................

[]

Needle bar height ................................................................................................................... 30

II]

Installation position of looper ................................................................................................

~

Needle and looper

I!]

Clearance between needle and needle guard ......................................................................... 32

timing

.......................................................................................................

III Installation position of retainer .............................................................................................. 32

[§] Installation position of

[1]

Presser foot lift stroke ............................................................................................................

[[]

Roller

feed

amount ................................................................................................................

[2] Thread tension ........................................................................................................................

[ I ] Troubleshooting .............................................................................................................................

feed

dog

............................................................................................

30

30

31

33
33
34
35

36

!

,.---

)

[A]

Model Plate Display

[!) Specifications

A Specifications

Plain stitching (without puller)

00
02

For

elastic gathered waistbands
(with bottom metering device)
(with puller)
For shirtfronts (with puller)

04

For

waistbands (with puller)

Needle gauge

Needle gauge (inches)
Full width

12

I 3

14

I 5

~

Full width 1
Full width
Full width
Full width

1/4

3/16 -7/8 -3/16

1/4 -3/4­1/4 -1/2­3/16-

1

3/16 -3/4

li] -

05

[Q

B:c

0 I 1
0
0
0

0
0'6
0 : 7
o:8
0 I 9

1 : 0
1

- 1

Device

3/4

1-1/8
1-1/4
1-1/2

-

1

- 3/16

- 3/16

Sp.ecs. Needle gauge

1/4

1/4
1/4

[lli

Device

Air

Type Tape Cutter

Solenoid Type Tape Cutter

- 1 -

-2-

/

[C] Description of Mechanism

@ The power is transmitted in the

[!] Needle

Slide block

bar

mechanism

f)

Thread take-up crank

order

0 Upper shaft L

of

the following numbers.

0 Coupler L

Up

and down motion

t

-

3-

[1]

Looper

tD

Looper holder

mechanism

8 Looper rod

0 Pin

Holder frame lever

Taper shaft

Pull

• Pull the plate so that the taper shaft end comes off the holder frame lever.
The spring works to

Jet

the looper down this side.

-4-

[I]

Retainer

8 Retainer shaft arm

0 Retainer shaft

mechanism

CD

Q)

Retainer holder

Retainer

«;)Pin

0 Feed link

8 Retainer arm

----...c!~~~~

Right and left motion

Cl

Holder shaft

-5-

~

Feed mechanism

1. Up

and

down motion/Forward

and

backward motion

(j) Feed bracket

@Rod

@Eccentric

pin

® Feed arm shaft

@Feed

wheel assembly

shaft

Swing

C)

Feed eccentric

Turning

direction

8 Lower shaft

8 Feed rod

(j)

•Up and down motion

•Forward and backward motion

2. Stitch length changing mechanism

Press the push button 0 and tum

C)

forward

changed.

and backward

to

the

change the eccentricity of

Press

pulley

so

0 Push button

l Up and down motion

that the tip engages

the

eccentric

with

the eccentric adjusting

wheel

assembly

Q.

cam

As

a result, the

fj.

Then

feed

tum

the

pulley

volume

C)

Alignment mark

will

Pulley

be

-6-

II] Presser foot lift mechanism

8 Presser lift M lever

G Presser lift lever L

Presser

Presser bar clamp

lift plate

0 Presser lift lever R

Step

on

the

pedal

[!]

Thread release mechanism

Step

on

the pedal

Tension disc

G Thread release arm

8 Thread release shaft

8 Thread release plate

-7-

[1]

Looper thread take-up mechanism

8 Take-up rod

Looper shaft

[£]

Puller mechanism

CD

Puller driving lever

8 Clutch lever

8 Pin

Take-up guide

0 Looper thread take-up

«!)

Plastic gear D

The

feed

@).

volume of the puller (plastic gear)

The

fine adjustment can

be

made

can

by

changing the

be adjusted

arm

by

changing the eccentricity of

length of

-

8-

the

puller driving lever

V-belt pulley

pulley D

Timing

Puller eccentric wheel assembly

the

puller eccentric wheel

t1

with

the

knob.

assembly

[2]

Lubrication

Trochoid pump

-9-

[D]

Disassembly Procedures

@ Disassemble the machine by removing the parts in the

[}] Cover

order

of

the following numbers.

0 Turn the pulley and drain the oil in the pump.

8 Belt cover

(V-belt)

(4.37 X 23)

0 Oil pan

8 Presser foot

f)

Loosen the screw of
presser lift stopper.

-~

(4.37

X~)

~

''~

fj)

(8

X 16)

m~

Needle

-

10-