JUKI DU-1181 Quick start guide

40040471

No.E371-00

ENGINEER’S MANUAL

1-NEEDLE, TOPAND BOTTOM FEED LOCKSTITCH MACHINE WITH A LARGE HOOK

DU-1181

DU-1181N

Introduction

This Engineer’s Manual is for technical service engineers. In the instruction manual for the maintenance engi-

neers of sewing machines and sewing workers in a sewing factory, how to operate a sewing machine is also

described in detail. However, in this manual, [Adjustment Procedure], [Results of Value Change for Adjustment],

and the roles of each component are described: these are not included in the instruction manual.

When maintenance is performed for our sewing machines, refer not only to this manual, but also to the instruction

manual and parts list.

This engineer’s manual describes the basic adjusting values as the reference values in the first page, and the

observed events caused by sewing and mechanical faults as the [Results of Value Change for Adjustment] and

[Adjustment Procedure] in the second page.

CONTENTS

1. Specifications ......................................................................................................... 1

2. Model Designation of the Head Section................................................................ 2

(1) DU-1181...................................................................................................................................... 2

(2) DU-1181N ................................................................................................................................... 2

3. Standard Adjustment.............................................................................................. 3

(1) Height of Needle Bar................................................................................................................. 3

(2) Timing between the Needle and the Hook .............................................................................. 3

(3) Lengthwise Position of Bobbin Case Positioning Finger ..................................................... 5

(4) Height and Position of the Feed Dog ...................................................................................... 5

(5) Feeding Alignment .................................................................................................................... 7

(6) Hand Lifter ................................................................................................................................. 7

(7) Upper Feed Motion.................................................................................................................... 9

1) Outer Presser Foot Position ................................................................................................................9

2) Amount of Interactive Movement of the Outer Presser Foot and the Inner Presser Foot .............9

3) Amount of Alternating Vertical Movement of the Outer Presser Foot and the Inner

Presser Foot..........................................................................................................................................9

(8) Upper Feed Differential........................................................................................................... 11

(9) Upper Feed Cam Timing......................................................................................................... 11

(10) Stitch Length in Forward and Reverse Feed ...................................................................... 13

(11) Thread Tensioner .................................................................................................................. 13

(12) Lubrication............................................................................................................................. 15

4. Grease Application................................................................................................ 17

5. List of Selective Combination Parts and Maintenance Parts............................ 19

6. Optional Parts........................................................................................................ 20

7. Troubles in Sewing and Corrective Measures.................................................... 21

8. Table Dimension Diagram .................................................................................... 24

1. Specifications

No. Item Specifications

1 Model DU-1181/DU-1181N

2Model Name 1-needle, top and bottom feed lockstitch machine with a large hook

3 Applications For medium-weight and heavy-weight materials

4 Sewing Speed Max. 2,000 rpm.

5Needle DP x 17#14 to #23 (Standard: #21), (DB x 1 available)

6Thread #40 to #8

7 Stitch Length Max. 9 mm (for both normal and reverse feed stitching)

8Presser Foot Lift Using hand lifter: 5.5 mm, Using a knee lifter: 15 mm

Stitch Length Regulating Method

Using butterfly dial

10 Reverse Feed Stitching Using hand lever

11 Thread Take-up Lever Link type

12 Needle Bar Stroke 36.5mm

13 2mm to 5mm

14 Hook Large hook with automatic lubrication system

15 Feed mechanism Feed forked connecting slider type

16 Top Feed Mechanism Linked with hook driving mechanism

17 Using beveled gear

18 Lubrication Automatic lubrication (Manual lubrication only for top feed section)

19 Oil Return Flow Circulated with plunger pump

20 Lubricating Oil JUKI Machine Oil No. 7 (equivalent to ISO VG7)

21 Grease JUKI Grease A (White)

Tube of 10g grease (Part No. : 40006323), or

500g can (P/art No. : 23640204)

22 Bed Size 178mm to 476.6mm

23 Space under the Needle 261mm to 122.6mm

24 Motor 4P-400W Clutch Motor

25 Transmission Belt M Type V-Belt

26 Weight of Machine Head 31Kg

– 1 –

Amount of Alternating Ver-

tical Movement of the Walk-

ing Foot and Presser Foot

Rotating Hook Driving

Shaft System

12 3 456789

DU 1181–

2. Model Designation of the Head Section

(1) DU-1181

Name: 1-Needle, Top and Bottom Feed Lockstitch Machine with a Large Hook

– 2 –

8Specification Code for Destination

AStandard (WEEE compatible)

GChina (within China)

DU.S.A. and Japan

9Accessory Specification Code

AStandard

BCE compatibel

12 3 45678910

DU 1181N–

(2) DU-1181N

Name: 1-Needle, Top and Bottom Feed Lockstitch Machine with a Large Hook

9Specification Code for Destination

AStandard (WEEE compatible)

GChina (within China)

DU.S.A. and Japan

10 Accessory Specification Code

AStandard

BCE compatibel

(1) Height of Needle Bar

3. Standard Adjustment

Marker Lines engraved in the Needle Bar (for DP x 17): (Standard) A

Marker Lines engraved in the Needle Bar (for DB x 1): B

– 3 –

Requirement:

•The needle bar should be

brought to the lowest dead

point.

(2) Timing between the Needle and the Hook

1) Needle Lifting Amount and Positions of the 2) Clearance between the Needle and the

Needle and Blade Point of the Hook Blade Point of the Hook

Requirement:

•The needle bar should be lifted from

the lower dead point.

Standard Adjustment

Coincidence with

the lower line en-

graved on the

needle bar

1.2mm

2.5mm

Marker Lines engraved in the Needle Bar (for DP x 17): (Standard) C

Marker Lines engraved in the Needle Bar (for DB x 1): D

0.02 to 0.07mm

1. Turn the hand-wheel to bring the needle bar to the lowest dead point.

2. Loosen the clamping screw of the needle bar connecting bracket

3. Align the marker line Aengraved in the needle bar to the lower end

of the needle bar lower metal and fasten the clamping screw of

the needle bar connecting bracket .

(Cautions) 1. For the needle DP x 17 (Standard), use the second

marker line AA

Afrom the lowest, engraved in the

needle bar.

2. For the needle DB x 1, use the fourth marker line BB

from the lowest, engraved in the needle bar.

3. After adjustment, make sure that the outer presser

foot does not come in contact with the needle bar.

oStitch skipping or thread breakage

may be caused.

– 4 –

oIrregular stitches, stitch skipping

or thread breakage may be

caused.

oIrregular stitches, particularly

isolated idling loops, will occur

when the hook timing is too early

or too late.

oIrregular stitches can be improved

when the hook timing is

appropriately set later.

oWhen the hook timing is set too

late, the thread tension may be

lowered.

oIsolated idling loops can be

improved when the hook timing is

set appropriately earlier.

1) Needle Lifting Amount and Positions of the Needle and Blade

Point of the Hook

1. Loosen the set screw of the throat plate and remove the throat plate.

2. Lift the needle bar 2.5 mm up from the lowest dead point.

3. Align the marker line C(for DP x 17) to the lower end of the needle

bar lower metal .

For the needle DP x 17 (Standard), use the lowest engraved

marker line Con the needle bar.

For the needle DB x 1, use the third marker line Dfrom the

lowest engraved on the needle bar.

4. When the positions of the needle and the blade point of the

hook are adjusted, loosen the hook set screw and turn the hook

by hand. Then align the center of the needle with the blade point

of the hook.

2) Clearance between the Needle and the Blade Point of the Hook

1. When setting the clearance between the needle and the blade

point , loosen the hook set screw so taht the clearance of 0.02

to 0.07 mm is provided between the needle and the blade point

Adjustment Procedure Results of Improper Adjustment

1) Height of the Feed Dog

2) Position

Requirements:

•Feed Level: Maximum (9 mm)

•The clearances A and B between the throat

plate and the front and rear of the feed

dog should be equal.

Feed

base

Upper surface of

the throat plate

1.2mm

(4) Height and Position of the Feed Dog

– 5 –

Requirements

• Feed Level: Minimum (0mm)

•The maximum projection of the

feed dog should be 1.2 mm

above the surface of the throat

plate.

(3) Lengthwise Position of Bobbin Case Positioning Finger

Requirements:

•The needle entry should be within a range between

the center of the bobbin case positioning finger

projection and the shoulder section.

•The needle bar should be brought to the lowest dead

point.

Standard Adjustment

Range of Needle Entry

oThread tension failure may be

caused.

1) Height of the Feed Dog

1. Set the stitch dial to 0 mm on the scale.

2. Turn the hand-wheel and set the feed dog to the position where it

projects to the upper limit from the throat plate .

3. Loosen the feed driving fork end clamping screw to move the feed

driving fork end up and down and set the height of the feed dog

1.2 mm higher than the upper surface of the throat plate. Then, fix

the clamping screw.

2) Position

1. Set the stitch dial to 9mm on the scale.

2. Loosen the feed bar arm clamping screw and make sure that the

feed dog moves evenly to both the front and rear grooves on the

throat plate . Then, fix the clamping screw. (A = B)

– 6 –

1. Turn the hand-wheel to bring the needle bar to the lowest dead point.

2. Loosen the set screw of the bobbin case positioning finger .

3. Move the bobbin case positioning finger in the arrow direction so

that the needle entry is within the range between the center of the

projection on the bobbin case positioning finger and the shoulder

section and fix it using the set screw of the bobbin case position-

ing finger .

Adjustment Procedure Results of Improper Adjustment

If the height of the feed dog is

excessive:

oThe feed dog will come in

contact with the throat plate .

oThe stitch length may become

larger than the value specified in

the stitch dial.

oIrregular stitches may be caused.

If the height of the feed dog is

insufficient:

oThe stitch length may become

shorter than the value specified in

the stitch dial.

oThe feed driving force may be

weakened.

Position:

oThe throat plate may come in

contact with the feed dog , and

the feed bar arm may come in

contact with the bed, resulting in

abnormal noise.

First or second

tooth

(5) Feeding Alignment

Requirements:

•Feed Level: Maximum (9 mm)

•Just when the first or second tooth at the front end of

the feed dog is lowered from the upper surface

of the throat plate, the center of the needle hole

should come in contact with the upper surface

of the throat plate.

•The marker dot Aengraved on the feed driving cam

should agree with the marker dot Bengraved on

the feed rock cam.

Standard Adjustment

Hand-wheel

side

Earlier Later

– 7 –

(6) Hand Lifter

Requirements:

•The lifting amount of the inner presser foot should

be 5.5 mm using the presser lifting lever.

Standard Adjustment

5.5mm

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