JUKI LH-4128 User manual

LH-4100 series
Semi-dry-head, Direct-drive, High-speed,
2-needle, Needle-feed, Lockstitch Machine
LH-4128 / LH-4128-7 / LH-4168-7 / LH-4188-7

LH-4188-7
LH-4128
LH-4100 series
Even when the sewing material is changed or even
if the sewing process is difficult, the machine will adapt
itself to the circumstance and enables easy sewing.
By the adjusting thread tension at a multi-layered
part of the material or to the material thickness,
the machine is adaptable to a broader range of
sewing materials.

LH-4100 Series machines come with a direct-drive, semi-dry head,
and high & long arm to provide maintainability, silent operation
and beautifully-finished seams. This is the highest grade
2-needle lockstitch machine series launched by JUKI.
Range of sewing capabilities is
dramatically increased
Changeover between the needle feed
and bottom feed (LH-4128)
Needle-feed gauges
Bottom-feed gauges
Bottom-feed
Presser foot Throat plate Feed dog
Presser foot Throat plate Feed dog
Needle-feed
Changeover
JUKI's unique opener lays down
an elliptical locus
Soft opener which helps reduce
operating noise of the machine
※To changeover between the needle feed and bottom feed,
the replacement of gauges and a simple adjustment are required.
※JUKI's feed method permits adjustments of the timing between
the needle and feed dog, which affects the sewing performance of
the machine.
The LH-4100 Series has been designed laying importance on
the ease of thread tension adjustment in cases of the changing
of sewing materials ranging from light-weight (soft) to heavy-
weight (hard). All thread paths on which the needle thread
and/or bobbin thread passes have been totally rechecked to
ensure a range of sewing capabilities that is substantially
broader than that of the conventional models.
The opener achieves a silent operating environment which
has never been obtained by the conventional ones. It guides
the bobbin case with literally a "soft touch" to reduce bobbin
thread tension, thereby helping tense the thread uniformly
and produce beautifully finished seams.
For example, for processes such as the topstitching of
brassier cups and top-center plait of men's shirts, which
need to be sewn so as to prevent puckering, the use of
a bottom feed gauge is recommended. The bottom feed
gauge is effective at the prevention of puckering and
enables sewing with a lower tension applied to the thread.

LH-4128-7 LH-4168-7
127mm
267mm
Filament thread (high-count)
Filament thread
(medium- to low-count), Span thread
The machine comes with a newly developed needle clamp to increase the stability of needle-thread loops and to reduce untwining
of the thread. The needle clamp works to improve the right and left seam balance and prevent thread breakage, in an idling
stitching process, by changing needle threading according to the type and thickness of thread.
The machine is provided with a high & long arm which facilitates the handling of sewing products even when sewing large ones
such as jeans. In addition, increased stop accuracy and excellent responsiveness, which are the most prominent features of
the direct drive, work in combination with the high & long arm to help eliminate operator stress, thereby increasing productivity.
※The machine has the largest distance from needle to machine arm among any other similar models regardless of manufacturer, i.e., JUKI and its
competitors.
New model of wire-type needle clamp
Sewing environment which ensures excellent workability
JUKI always pursues new technologies
to offer machines which promise consistent quality
with improved workability and durability.

Separately driven needle bars which provide
outstanding durability and holding power
(LH-4168-7, LH-4188-7)
Right-needle stop switch
Left-needle stop switch
Separately driven
needle bars
(Organized split
needle bar)
JUKI's unique
separately driven
needle bars are
housed inside.
Teaching function
The number of
stitches in
a sewing area with
one of the needle
bars held idle, is
automatically stored.
Optional panel: IP-110B
The machine is installed with JUKI's newly developed
unique separately driven needle bars. When one of
the needle bars is stopped, it is held in place with
added stability. This mechanism demonstrates
outstanding durability. The machine is able to run at
the highest sti/min even when only one needle is in
operation (the other needle bar is held idle). This
feature totally eliminates a fundamental problem of
2-needle bar lockstitch machines, which is how to hold
either needle bar securely in an idle state.
■Corner-teaching function (provided as standard)
To start corner sewing, the operator need only press
the right or left stop switch. Then, the machine
automatically counts the number of stitches. This allows
the operator to concentrate on material handling.
Upon completion of corner sewing, the one-needle stop
state is automatically reset.
■Automatic feature (Optional panel : IP-110B and
Auto lifter : AK125 are required)
To sew two or more corners continuously, it is possible to
enter a sewing program on the IP panel to automatize a
sewing sequence from the beginning of sewing to thread
trimming (including sewing of two or more corners).
As many as 20 steps of constant-dimension sewing and as
many as 8 different corner patterns can be stored in one
program. In addition, various conditions such as the
up/down position of the needle bars, up/down position
of the lifter, forward/reverse feed and automatic thread
trimming can be set on a step-by-step basis.
For sewing pockets on men's shirts, hip pockets on jeans and topstitching on collars, a corner sewing process is required without
exception. The machine is provided with a function for automatically or semi-automatically sewing the corner sewing process with
ease.
The function for separately driving the needle bars is automatically reset (LH-4168-7, LH-4188-7)
●Teaching function
1. Press the left-needle stop switch at point A to stop the left needle.
2. Perform sewing with the left needle bar held idle until point B is reached.
(The number of stitches is automatically stored in the memory)
3. At point C, the left needle, which has been held in an idle state, is
automatically released.
No resetting
operation is
required.
AB
C

Oil tank
Capacity: 220cc
Application
Dry type
Max. sewing speed
Distance from needle to machine arm
Needle gauge
Feed system
Max. stitch length
Thread take-up
Separately driven needle bar changeover mechanism
Opener system
Tensioner
Thread trimming method
Thread winder
Lift of the presser foot
Lubrication
Tank capacity
Lubricating oil
Needle
Power consumption
Outside dimensions of package
Machine head weight (including the package)
LH-4100 Series
F: Foundation S: Medium-weight G: Jeans and heavy-weight materials
Semi-dry-head
LH-4128(-7): 4,000sti/min LH-4168-7, 4188-7: 3,200sti/min
127mm(H)×267mm(W)
Changeover between the needle feed and bottom feed
5mm
Link type
Needle bar shaft link changeover method
Soft opener
Integral type (lockstitch type)
Direct-acting type
Driven by the arm shaft
By hand: 5.5mm, By knee: 13mm
Centralized tank system
220cc
JUKI New Defrix Oil NO.1
DP×5 #9〜#22 (S and F type) #16〜22 (G type)
650VA
739mm (H) × 378mm (W) × 768mm (L)
LH-4128 (-7): 68kg, LH-4168-7, 4188-7: 73kg ※+3 kg for the machine provided with an AK25.
LH-4128
LH-4128-7
LH-4168-7
LH-4188-7
1 / 8"〜1-1 / 2" (3.2〜38.1mm)
5 / 32"〜1-1 / 4" (4.0〜31.8mm)
5 / 32"〜1" (4.0〜25.4mm)
Model name
JUKI's dry technology has achieved the adoption of a dry
frame in all classes of machines, including those with
separately-driven needle bars (organized split needle
bar)/large hook. The dry frame eliminates oil dispersion from
the thread take-up and needle bar frame section, thereby
achieving a clean sewing environment. In order to use clean
oil in the hook section at all times, a centralized tank system
has been adopted for oiling. In addition, the hook section is
oiled using independent left and right pumps and oil paths,
whereby consistent oiling of the hook section is enabled
without being affected by the single-direction oil flow.
Replacement and adjustment of the gauge is necessary in
order to change the needle gauge according to the targeted
sewing operation. For the LH-4100 Series, the aforementioned
work is dramatically improved in efficiency.
The hook driving shaft saddle can be moved only by
loosening the screw in the base. In this case, neither the hook
driving shaft gear nor lower shaft is required to be loosened.
In addition, the hook does not turn when moving the hook
driving shaft saddle. This means that "hook timing
adjustment", which is the most troublesome work
associated with the procedure, is not required. As a result,
the time required to complete the gauge replacement for
this machine is reduced to a half or less as compared with
the conventional machines.
Dry frame is achieved for all classes of machines
Trouble and time required to change the gauge is reduced
to half or less (applies to all classes of machines)
SPECIFICATIONS
Hook timing adjustment is not required
Hook timing adjustment is not required
after needle gauge changing.
after needle gauge changing.
Hook timing adjustment is not required
after needle gauge changing.
To change the needle gauge in the hook
section, adjustment is possible only by
loosening the screw in the hook driving
shaft saddle.
Hook driving
shaft saddle
(left)
Hook driving
shaft saddle
(right)

WHEN YOU PLACE ORDERS
Dry type
Semi-dry-head
Code
S
Semi-dry-head
Dry type Code
S
Feed system
Needle-feed
Code
A
Wiper and automatic reverse feed function
Not provided Provided
Wiper
Automatic
reverse
feed function
Code
0B
Auto-lifter
Not provided
Provided (pedal-driven)
Code
AK125
Attachment (throat plate)
Standard gauge
(throat plate, slide plate,
presser foot)
For tape attaching
(throat plate, slide plate,
presser foot with guide)
Code
1
4
Foundation
Medium-weight
Jeans and heavy-weight
Application Code
F
S
G
Needle-feed
Needle-feed with organized split needle bar
Code
28
68
Needle gauge LH-4128S
inch
1/8
3/16
1/4
1
mm
3.2
4.8
6.4
25.4
F
○
○
○
−
S
−
○
○
○
G
−
−
○
−
LH4128 S □□A0B□□□□□□
LH41□□ S□F A 7WB□□□□□
B
D
F
Q
Code
Needle gauge LH-4188S-7
LH-4128S-7
LH-4168S-7
inch
1/4
mm
6.4
S
○
G
○
S
−
G
○F
Code
Auto-lifter
Not provided
Provided (pedal-driven)
Code
AK125
Application
Medium-weight
Jeans and heavy-weight
Code
S
G
Operation panel
CP-18A
CP-180A
Inetelligent panel
IP-110B
Type
○ mark: Gauge which is factory-installable at the time of delivery.
※ Various kinds of gauges are available in addition to those listed
here. Refer to the Instruction Manual and Parts Book for details.
Please note when placing orders, that the model name should be written as follows:
●To order, please contact your nearest JUKI distributor.
○mark: Gauge which is factory-installable at the time of delivery.
※Various kinds of gauges are available in addition to those listed here.
Refer to the Instruction Manual and Parts Book for details.
※For the operation panel “CP-18A” or “CP-180A” , machine
type “LH-4128” and “LH-4128-7” can be selected.
※For the operation panel “IP-110B” , machine type
“LH-4168-7” and “LH-4188-7” can be selected.
※When the sewing specification classification F
is selected, attachment 4 should be selected.
※When the sewing specification classification S
or G is selected, only attachment 1 is selectable.
Feed system
Needle-feed
Code
A
Wiper and automatic reverse feed function
Provided Provided
Wiper
Automatic
reverse
feed function
Code
WB
Needle-feed with organized split needle bar
and large hooks
88
■Without automatic thread trimmer
■With automatic thread trimmer
■Operation panel

OCTOBER, 2011 Printed in Japan(C)
SEWING MACHINERY BUSINESS UNIT
2-11-1, TSURUMAKI, TAMA-SHI,
TOKYO 206-8551, JAPAN
PHONE : [phone]
FAX : [phone]
http://www.juki.com
✽ Specifications and appearance are subject to change without prior notice for improvement.
✽ Read the instruction manual before putting the machine into service to ensure safety.
✽ This catalogue prints with environment-friendly soyink on recycle paper.