Mitsubishi LS2-190 Manual

A
MITSUBISHI
Industrial Sewing Machine
Technlcai Information
Model LS2-190
Automatic Undertrimmer
Single-Needle Lockstitch
Sewing Machine
ET-009A
ITSUBISI
ELECTRIC
A MITSUBISHI
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CONTENTS
mConstruction 1
fn Specification 3
[31 Detail schema of thread trimmer system 5
1. Electric section 5
2. Machine head section 6
3. Diagrams of thread-trimmer knife motion 8
IXI Preparation before operation 9
1, Installation of sewing machine and motor 9
2, Adjustment of needle bar stop position 10
in Adjustment 1
1. General 1
2, Thread trimmer system 1
2.1 Mechanism 1
2.2 Cautions on adjustment 1
3» Disassembling each unit 1
3.1 Knife drive mechanism i
3.2 Picker and thread trimming actuator 12
3.3 Knife assembly 12
4., Assembling and adjustment 12
4.1 Knife assembly 12
4.2 Picker and thread trimming actuator 15
4.3 Knife drive mechanism 18
4.4 Adjustment of length of needle thread end
after trimming 23
4.5 Floating foot 23
4.6 Adjustment of touch-back pushbutton position 24
4.7 Wiper 25
4.8 Cautions on installation of solenoid 25
4.9 Hook, feed dog, bobbin case and bobbin 26
4.10 Adjustment of feed dog inclination 26
[6l Trouble shooting 28
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(ftlUK
Q Arm shaft
0 Take-up lever
0 Thread guide
® Needle bar
(H) Feed rock shaft crank,
(left)
® Picker
(g) Thread guide
Pre-tension
Presser bar spring
i
Presser bar regula
ting thumb screw
Tension regulator
Presser bar lifter 0 Presser bar
@ Movable knife
(Q) Eccentric shaft
(g) Picker bracket
Knife bracket
- 1 -
Feed bar
Feed dog
Fixed knife
Thread guide
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Oil check window Balance wheel @) Synchronizer
Feed forked connecting Feed regulating dial (g) Vertical shaft
rod
Reverse sewing lever (§) Cam shaft bracket (g) Feed rock shaft
Crank rod (§) Feed lifting shaft (§) Oil pump
Hook shaft ® Thread trimmer solenoid @ Thread trimmer cam
Gam follower crank @ Knee lifter (§) Actuating crank
Gam shaft
- 2 -
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Specification
~ Model
Item
LS2-190-M1T LS2-190-M1TW
LS2-190-H1T
Material weight
Light to medium
Heavy
Max. sewing speed
5,000 S.P.M
3,500 S.P.M.
Max. Stitch length
* Note 1
0 Umm
Needle bar stroke
31.8mm
33.0mm
Presser foot
stroke
Knee lifter(Max.)
/ Manual
11mm/5mm
Needle
DB X 1 #14
DB X 1 #22
Throat plate
(Needle hole)
(Needle hole)
Hook
Full rotation, automatic
lubrication
(Thread trimmer type),
Standard type
Full rotation,
automatic lubrication
(Thread trimmer type).
Heavy dury t^^e
Bobbin case
Bobbin case with racing prevetion spring
Bobbin
Thread trimmer type steel bobbin
Thread trimmer
Fixed and movable knives
Thread trimmer
smarting method
Solenoid excitation
Hiread trimmer
drive system
Gam drive
Thread trimming
speed
200 rpm
Touch-back
OOO
Wiper
O
Bed size
475 X 178mm
- 3 -
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Note 1. T; Touch-lDack equipped TW: Wiper and touch-back equipped
- 4 -
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3.2. Machine head section (l)
I
Parts Name
d) Flexible wire
Thread tension
release assy
Needle bar connecting
link guide
® Spring
® Movable knife
Picker actuating link (6) Cam shaft
Picker bracket
Knife driving fork @ Movable knife crank
Movable knife
adjusting bracket
Cam shaft bracket
Trimmer cam
Trimmer knife bracket
®Trimmer actuating
crank
® Trimmer solenoid
@) Roller shaft bracket
@ Thread guide
(D Picker
Fixed knife
Picker drive crank
Drive crank
Cam follower crank
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5.2. Machine head section (2)
(D
m
Parts Name
0
stepped shaft
(D Cover
(D
Screw
Switch
(D Cover
(D
Switch
Torsion spring
(8) Solenoid bracket
(D
Wiper solenoid
©
Wiper connecting
(g) Pushbutton lever
(0)
Wiper connecting crank
Wiper bracket
©
Stepped shaft
© Wiper
Back solenoid
Side cover
@ Gasket
Plunger
(§1
Link
© Bushing
Peed regulator
(§)
Spring bracket
{§) Reverse sewing crank
Reverse sewing lever
shaft
©
Reverse sewing lever
(g) Spring
Spring bracket
(§)
Spring
- 7 -
m
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3-3 Diagrams of thread-trimmer knife motion of Model LS2—190
1. Starting of trimming motion
(needle at low position)
Movable knife
2. Movable knife spreads and assorts
the thread as it moves forwards.
Hook point
Picker
3.
Fixed knife
Cutting blade area
Thread guide groove
Movable knife catches the two
threads(needle thread and bobbin
thread) as it retreats.
- 8 -
Thread catcher hook
4. Thread trimming
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[4] Preparation before Operation
1. Installation of sewing machine and motor
Arm
Face plate
5
Phase reversing plug
I I
LIMI-STOP clutch motor
Control box
/I
•
Balance wheel
-1=] ^ Synchronizer
Belt
eft E®
Plug from
machine
Rubber cap
•Power on/off switch
Switch panel
Passing the machine cords
Table round.
Switch panel^^^°^®
^ake ^ Switch panel
ID ' iig fl^ j
Power liriq ^
Clutch ^Option |Machine
Speed Synchronizer
Wiring between sewing machine and control box
Note: Before plugging or unplugging, be sure to depress Power ON/OFF
I)Ushbutton to "OFF".
Pass two cables from the sewing machine through the round hole in the
table and put the two plugs into the respecitive plug receptacles.
- 9 -
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2. Adjustment of needle position
Timing mark0 is contacted with the first timing mark © and stops
after completing the trimming hy kick-up of the pedal. Materials are
fully adjusted, however, if the gap is above 3 mm, adjust the set
position of the magnet disk as follows.
Preparation
1. Take off the plug (with twelve (12) pins) of the cord coming out
of the machine head from the controller.
2. Remove the detector cover.
3. Operate the machine and stop it at a needleup position, and make
the following adjustments under this condition.
Adjustment
1. Loosen the set screw (5) while supporting the magnet disk hy
hand, fit the timing mark® and ©by turning the balance wheel,
then tighten the set screw ® again.
2. Step on the pedal and repeat kick back operations several times
to ensure that the stop position is stabilized.
3. Insert the plug (l2 pins) coming out of the machine head after
the^stop position has been stabilized.
Second timing
Mark
©
First timing
mark
- 10 -
Magnet disk
Screw
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Adjustment
1, General
Since the sewing machine LS2—190 is a version of the standard single-
needle lockstitch machine and equipped with thread trimmer, the con
struction does not differ from the standard one except for the thread
trimmer system and therefore description in this Manual is mainly con
cerned with the thread trimmer,
2, Thread trimmer system
2.1 Mechanism
The thread trimmer construction can be largely divided into four
sections: namely, knives, knife drive mechanism, picker and trimming
actuator, and synchronizer, each of which is of unit construction.
Thanks to the unit construction, each section can be independently
adjusted and installed with ease,
2.2 Cautions on adjustment
A hook shaft cam drive system is employed in the trimmer.
In this drive system, if the machine runs with the roller (cam
follower) engaged in the trimmer cam groove at adjustment of the
sewing machine, for example, the movable knife comes into contact
with the needle and/or feed dog and will be damaged.
Therefore, the roller should enter the cam groove only in normal
trimming cycle,
3, Disassembling each unit
3.1 Knife drive mechanism (cam shaft bracket unit)
3.1.1 Remove the stepped screw (A),
3.1.2 Remove the two screws (B) to remove the stopper plate (C).
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3#1«3 Remove the three cam shaft bracket clamping screws (g).
Now the cam shaft bracket unit can be removed.
3.2 Picker and thread trimming actuator (Fig. l)
3.2,1 Remove the stepped screw 0•
3.2.2, Loosen the screws ® ,© to remove the flexible wire.
3.2.3 Remove the two screws ® to take out the solenoid bracket.
Now the picker and thread trimming actuator can be removed,
3.3 Knife assembly (Fig, l)
3.3.1 Remove the hook.
3.3.2 Remove the two knife assembly clamping screws Q.
Now the knife assembly can be removed.
Trimmer knife
bracket
DSolenoid bracket
3 ®
Cam shaft bracket unit
Picker
©
Fig, 1
4-. Assembling and adjustment
4.1 Knife assembly
4.1.1 Fig, 2 shows the standard installation and adjustment of the
fixed knife and thread guide.
\U]
0\eb w
C-=,
- 12 -
© Flexible wire
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To adjust the relationship between the thread guide and the knife,
loosen the two fixed knife clamping screwes 0
0.5 MI 12.5m
Thread guide
Fixed knife ®
Fig. 2
4..1,2 The knife assembly should be installed in the dimension
shown in Fig, 3 to the sewing machine.
To adjust the knife in reference
to the needle position, loosen
the screws ® .
Center of needle position
2 m
Knife bracket
Fig, 3
4#1,3 Setting of movable knife and engagement with fixed knife
(l) In the standard engagement,
the fixed knife comes into
contact with the movable knife
when they are positioned as
shown in Fig, 4-«
- 13 -
Movable knife
Fixed knife
Fig, 4
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(2) Adjustment of knife engagement
i) Loosen the movable knife crank set screw 0 •
ii) Loosen the screw (g) and turn the adjusting screw © to
assure good engagement of the knives.
Knife engagement becomes tight when the adjusting
screw © is turned clockwise.
Knife engagement becomes loose when the adjusting
screw © is turned counter-clockwise.
Movable knife
Movable
©
Fig. 5
Trimmer knife bracket
iii) Tighten the screw d) .
iv) Lightly pushing the movable knife crank against the trimmer
knife bracket with the knives fully engaged, tighten the set
screw 0.
4.1.4- Installing the knife assembly unit
Install the knife assembly unit in reverse steps to the disassembling,
Replacing the movable knife
To replace the movable knife, proceed as follows;
1) Remove the throat plate.
2) Loosen the movable knife crank set screw 0 .
- 14- -
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3) Take out the movable knife.
(Take care not to lose the ball at the movable knife shaft end)
4.) Put the ball in the recess provided at the movable knife shaft
end.
(For easy installation, previously apply grease on the recess
and install the movable knife to the knife bracket.)
5) Adjust knife engagement as described previously.
A*2 Picker and thread trimming actuator
4.2.1 Installation
1) Assemble the parts as shown in Fig. 6.
2) Install the solenoid bracket using the two screws (S) .
3) Install the picker bracket using the stepped screw (B) •
Picker
Picker
bracket
Solenoid bracket
Picker actuating link
X
—nAg Rotary^
solenoid
0
Trimmer drive crank
Picker drive crank
Fig. 6
4.2.2 Connecting the thread trimming actuator with cam shaft bracket
unit (Fig. 7)
1) Connect the trimmer crank with the link by the stepped
screw © •
- 15 -
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2) Loosen the trimmer drive crank set screw (g). Keeping the stepped
screw ® in contact with the stoprer port of stopper plate © ,
fully turn the armature counter-clockwise.
3) When the armature has been fully turned, maintaining the trimmer
drive crank in that position, turn only the armature clockwise
(to 1 - 2mm on the outer diameter) and tighten the screw © •
Armature
Link
1~2
Q)
©
1 a»
Trimmer
drive
crank
Fig. 7
4-.2.3 Adjustment of plcKer (Fig. 8)
1) Loosen the two screws © so that a gap of 1 - 1.5mm is developed
between the picker bracket and the feed bar and move the picker
drive plate to properly position the picker.
2) Position of picker in motion
The picker should be so located that the picker end can enter
the bobbin case recess center and is positioned in 0.5 - 1mm
apart £rom the bobbin side face.
To adjust the picker, loosen the two screws (S) •
Note: When this gap (0.5 - 1 mm) is too large, the needle
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thread leaves the picker at thread trimming and will
be trimmed with short thread end, thus the thread may
come off the needle.
On the contrary, the picker comes into contact with
the bobbin when the gap is adjusted too shortly, making
impossible rotation of the bobbin, thereby bobbin thread
is trimmed too short causing skipped stitch at starting.
0.5~1 an
Bobbin
Picker
I'-l.bBa
W
Picker
drive plate
(D
Fig, 8
4..2,4.
Adjustment of needle thread tension releasing
1) Securely clamp the flexible wire end sleeve witn the holder (2)
2) Hold the wire (g) by the plate © .
Lightly pull the wire to
eliminate slack of the wire
and tighten the screw ® .
Note: Turn the balance wheel
by hand to actuate the
thread trimmer and
make sure the tension
discs open about 1mm.
Fig. 9
- 17 -
(g) Flexible wire
"About 1mm
Tension regulator casing
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If the tension discs do not open sufficiently, the needle
thread will be trimmed too short and'come off the needle
eye.
Too widely opened tension discs, however, do not give a
suitable tension to the thread.
Note: Disc opening depends on the position of the tension
regulator casing. To obtain the optimum opening of the
discs, the groove of the casing, in which the thread
take-up spring is set, should be in line with the arm
boss surface.
Knife drive mechanism
4-*3*l Adjusting the cam shaft bracket unit
Fig, 10 shows the standard construction of the unit,
1) Adjusting the cam follower crank
i) Axial direction of the cam shaft: iLoosen the screw ® to adjust
the cam follower crank in the axial direction of the cam shaft,
ii) Play in cercumferential direction of the cam shaft: To eliminate
play in the circumferential direction of the cam shaft,
adjust position of the roller.
2) Adjusting the knife driving fork
\
i) Loosen the screw (D to adjust position of the fork,
3) Adjusting the roller shaft
i) Loosen the set screw © to release the roller shaft,
4.) Do not loosen the nuts ©
When the nuts were loosened, be sure to securely tighten them.
If the nuts become loose, the roller cannot properly enter the
cam groove and thread cannot be trimmed.
- 18 -
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