Singer 471U User manual

SERVICE MANUAL
FOR
SINGER MODEL 471U
THE SINGER COMPANY
From the library of: Superior Sewing Machine & Supply LLC

CONTENTS
(C MECHANISMS 1) 1
|T| Needle bar mechanism 1
m Rotary hook mechanism I
ITj Needle zigzag mechanism 2
|T| Feed mechanism 3
m Clutch mechanism 4
B Cutter mechanism (1) 6
B Cutter
mechanism (II) 7
[Tj Upper thread cutter mechanism 8
B Lower thread cutter mechanism 9
[lo] Presser bar lifter mechanism 9
Tension releasing mechanism 10
fll]
Clutch and brake 29
fi2] Cutter safety device 29
[III Needle bar 31
ini Rotary hook shaft 32
[i^ Upperclamping foot and lower
thread cutter 33
[I^ Base needle plateand cutter
position control 34
Oil Upper clamping foot position control ... 35
M Rotary hook 35
[li] Lubrication 36
[2ol Needle sidewise movement
adjustment 36
(HI Needle zigzag reference
position adjustment 36
HH Scissors assembly position control 38
HD Scissors guide position control 38
[24] Covers 39
((ADJUSTMENtH) 40
Needle sidewise movement
adjustment 40
Needle bar and rotary
hook adjustment 40
Upper clamping foot lifter
adjustment 42
Cutter adjustment 44
Buttonhole width and reference
position adjustment 46
Upper thread cutter adjustment 48
Lower
thread cutter adjustment 50
Movable knife and fixed
knife adjustment 50
((DISASSEMBLY PROCEDURES)).
m
m
m
B
B
B
m
B
Covers
Lower thread cutter
Presser
Rotary hook
Upper thread cutter
Length feed
Clamping foot
Cutter safety device
[9] Clutch and brake
U
un
M
M
0
Feed
Needle bar
Cam relay
Upper shaft
Auxiliary
shaft
Needle zigzag
Needle breakage detection
Cutter
Lower shaft and rotary
(C ASSEMBLY PROCEDURES 1
B Lower shaft
U] Cutter
IT] Thread breakage detection
[Tj Needle zigzag
[Tj Auxiliary shaft
|T| Uppershaft
m Cam relay
(D Feed
rri upper clamping foot
flo] Upperthread cutter
14
m
15
15 m
16
16
m
17
17
m
18 m
18
19
m
19
m
m
20
m
21 M
0
21 mi
21
23
p]
23
24
26
27
(Hj
27
28
Qzl
28
OH
Belt shifter adjustment 52
Lubrication
adjustment 53
Tension pulley
adjustment 54
Bobbin winder
adjustment 54
Main tension and auxiliary
tension adjustment 55
Thread breakage detection
adjustment 56
Adjustment for changing the
stitch number 57
Cutter safety device adjustment 57
Adjustment of feed cam segment 59
From the library of: Superior Sewing Machine & Supply LLC

(MECHANISMS ))
[T] Needle bar mechanism
&
When the pulley O rotates in the direction of the arrow, this movement is transmitted to the thread take-up
crank O fixed on the end of the upper shaft O-
The needle bar crank O is fixed to the thread take-up crank O, andan up-down motion is transmitted tothe
needle bar clamp O through the needle bar crank rod 0.
The needle barO is fixed to the needle bar clamp 0 and is guided by the vertical bushing on the needle bar
support 0 so that is moves smoothly up and down.
[T] Rotary hook mechanism
0
0
00
0
1. When the pulley 0 rotatesinthedirection ofthearrow,this movement istransmitted tothetiming pulley U0
fixed on the upper shaft 0.
2. The timing belt0 is wrapped around the timing pulley U0 and assures sure transmission of the rotating
movement of the upper shaft to the timing pulley D 0.
3. Thetiming pulley D0 is fixed to thelowershaft0 and transmitstherotating movement tothelowershaftgear
0 fixed to the end of the lower shaft 0.
4. The rotary hook shaft gear0 mesheswith the lowershaft gear 0, and therotating movementistransmitted to
the rotary hook shaft 0.
5. The rotating hook assembly 0 is fixed on the rotary hook shaft 0 and rotates completely.
- 1 -
From the library of: Superior Sewing Machine & Supply LLC

|T| Needle zigzag mechanim
DilQvi
1. Whenthe pulley O rotates in thedirection ofthe arrow, the rotating movement istransmitted to the reduction
gear O fixed on the upper shaft Q-
2. Thereduction gear© meshes with thesubshaftgear reduces therotation oftheuppershaft© by half, and
transmits this motion to the sub shaft ©.
3. The needle zigzag cam © is fixed to theauxiliaryshaft ©, and the triangular portion of the needle zigzag cam
fits in the needle zigzagforked link ©.
4. The upper end of the needle zigzag forked link © is fitted on the needle zigzag link ©, and an oscillating
movement is transmitted to the needle zigzag lever R © linked with the lower end of the needle zigzag forked
link ©.
5. The needlezigzaglever F © isfixed on the needlezigzagleverR © and causes the needlebarframe slideblock
o fitted on the end of the needle zigzag lever F © to oscillate.
6. The needle bar support slide block © fits in the groove of the needle bar support © and causesit to oscillate
back and forth.
-2-
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Q] Feed mechanism
0
1. When the upper shaft O rotates in the direction of the arrow, the worm O fixed to the upper shaft O also
rotates.
2. The worm wheel O meshes withthe worm o ,and therotating movement istransmitted tothe worm wheel shaft
o
3. The change gear R0 attached to the end of the worm wheel shaft O meshes with the change gear O, which
causes the change gear shaft 0 to rotate.
4. The free wheel gear 0 fixed on the change gear shaft 0 meshes with the feed cam 0 causing it to rotate.
5. The roller 0 attached to the end of the feed adjusting lever 0 fits inthe heart-shaped groove ofthe feed cam and
causes the feed connecting rod 0 to move back and forth using the feed adjusting lever shaft 0 asa pivot point.
6. The end of the feed connecting rod 0 is linked to the feed drive shaft arm pivot point 0 and causes the length
drive shaft feed arm 0, clamping foot 0, and length feed plate 0 connected to the feed drive shaft arm pivot
point 0 to move back and forth.
ffiGear ratios
Change gear R
1 /30 rotation
1 rotation
Change gear L
1 reduction gear
1 rotation
2 rotations
1 /2 rotation
'J
Bychanging the gear ratio (change gear combination) of the upper shaft rotation with respect to one rotation
(one cycle) of the feed cam, the number of stitches can be varied between 58 and 347.
-3-
From the library of: Superior Sewing Machine & Supply LLC

U] Clutch mechanism
O
1 Starting
1. When the starting leverO islowered inthe direction of the arrow, it pressesagainst the lowerend of the clutch
lever causing it to pivot on the clutch lever shaft O ^nd move in the direction of the arrow.
2. When the clutch levere moves in the direction of the arrow, the stop leverclawO fixed on the stop lever0
rises to mesh with the clutch claw O fixed on the clutch lever 0
3. The belt shifter drive lever0 isfixed on the end of thestop lever 0, and the beltshifter roller 0 attached to the
lower end of this moves the top side of the belt shifter cam 0 attached to the belt shifter lever 0.
4. The belt shifter lower 0 linked to the belt shifterlever 0 moves in the direction of the arrowto shift the flat belt
to the low-speed pulley.
II Belt shifter
The belt shifter U 0 and the belt shifter lower 0
fixed to the clutch lever are linked to the movement
of the clutch lever and shift the flat belt between the
high-speed pulley and low-speed pulley so as to
transmit a stable rotation to the machine.
0-^ 1)1
/// // High-speed pulley
-4-
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III Stopping
1. When thestopcamcontact plate0 fixed tothestop lever comes incontact with thestopcam segment B ®, the
stop lever tongue O moves one step away from the clutch tongue O-
2. When thestopcamcontactplate0 fixed to thestop lever 0 comes incontactwiththestopcam segment A 0,
thestop lever tongue 0 moves away from the clutch tongue 0, and the clutch lever returnspring moves the
clutch lever 0 backinthedirection ofthearrow.Theclutchstopper0 entersthe groove onthestopcam0 and
stops the machine.
IV Emergency stopping
1. When the emergency stop arm 0 is pushed down,
the tongue of the emergency stop lever 0 meshes
with the clutch tongue 0, and the machinegoesto
slow-speed operation.
2, When the emergency stop arm 0 is released, the
tongue of the emergencystop lever0 movesaway
from the clutch tongue
0, and the machinestops.
-5-
From the library of: Superior Sewing Machine & Supply LLC

Ul Cutter mechanism (I)
0
0
1. When the sub shaft O moves in the direction of the arrow, the cutter eccentricrod O fitted to the cutter
eccentric wheel O fixed on the sub shaft oscillates.
2. The cutter drive lever O is linked to the end ofthecutter eccentric rodO andso oscillates inthe same way.
3. When thecuttercam segment 0 attachedto the feed cam pushed against thecutterpushbar 0, the clutch 0
riding on the clutch collar 0 moves to the clutch set collar 0.
4. When the cutter push bar 0 movesaway from the cutter cam segment 0, the clutch 0 falls in between the
clutch collar 0 and the clutch set collar 0.
5. When this happens, the cutter drive lever 0 entersthe dent in the clutch 0 and lifts it up.
6. Thelowerendoftheclutchis linked tothecutteroperationarm0 andcausesthecutteroperationlink0 linked
to the end of the cutter operation arm 0 to move up and down.
7. Thecutter holder0 islinkedtothecutter operationlink 0, and thecutteroperationshaft0 fixed tothecutter
holder 0 is moved up and down.
-6-
From the library of: Superior Sewing Machine & Supply LLC

|T] Cutter mechanism (II)
I Cutter drop prevention mechanism during thread breakage
I. Whenthe needlethread breaks, the thread breakage perceivingleverO automaticallycomesdown,and theend
ofthecutter clutch stopper O fixed to the thread breakage perceiving lever shaft O catches onthepinofthe
clutch O and stops the cutter from falling.
Stop cam tab A
Thread take-up lever link
Lever
II Cutter drop prevention mechanism during high-speed operation
1. When the clutch lever rises, the cutter stop connection rod 0 is pushed in the direction of the arrow, and the
movement is transmitted to the cutter stop lever O linked to its end.
2. The cutter stop levershaft O is fixed to the cutter stop leverO and transmits the movementto the stop lever
bracket O.
3. The clutch stop leverbracket O fixed to the stop leverbracket O ismoved inthe direction of the arrow. This
holds the pin of the clutch O and locks it securely in place, thus stopping the cutter from dropping.
-7-
From the library of: Superior Sewing Machine & Supply LLC

U] Upper thread cutter mechanism
Clamping
Cutting
thread
Scissors U
&
Clamping foot
1. Whenthe presser bar lifterconnectingrod O movesinthedirection ofthe arrow, presserlifter0 drops down in
the direction of the arrow pivoting on presser lifter lever shaft O.
2. The trimming clutch guideO isfixedon the end of the presser lifter ^nd the clutch cam0 isfixedon this and
drops down in the same way.
3. When the clutch cam 0 comesaway from the trimming clutch plate O, the upper thread trimming leverO is
moved in the direction of the arrow by the scissors operating spring O.
4. The upper thread trimming lever B O is fixed to the end of the upper thread trimming lever 0, and the
movement is transmitted to the scissors D 0 fixed on the upper thread trimming B O.
5. The scissors M 0 attached to the scissors D 0 come in contact with the clamping foot, and the scissors M0
close to cut the needle thread.
6. The scissors guide 0 fixed on the length feed arm advances in the direction of the arrow when the machine is
started, and the scissors M 0 open.
-8-
From the library of: Superior Sewing Machine & Supply LLC