Brother B706 User manual

From the library of: Superior Sewing Machine & Supply LLC

CONTENTS
~MECHANISM~ .................................
~ASSEMBLY~ ...................................... 14
OJ Upper shaft and needle bar mechanism
OJ Needle bar ............................................ 14
[I] Lower shaft and rotary hook
[I] Feed mechanism (8706/ 8707) .............. 15
mechanism .......................................... ..
I1J Feed mechanism (8714/ 8716/ 8747) .... 16
[I] Feed mechanism (8714/ 8716/ 8747) .... 2
[I] Thread trimmer .................................... 17
[I] Feed mechanism (8706/ 8707) .............. 3 0
Rotary hook......................................... 18
0 Lubrication mechanism ........................ 4 [I] Presser mechanism ...............................
19
[I] Thread trimmer mechanism ................. 6
[]] Cover.................................................... 19
[]] Thread tension release lever
(8707/8716/8747)................................ 9
~ADJUSTMENTS~ ............................. 20
[I] Thread wiper mechanism ..................... 9
[!] Quick-back mechanism ........................ 9
OJ Needle and rotary hook timing
adjustments ..........................................
20
[]] Automatic presser lifter mechanism ..... 9
I1J Feed dog height adjustment ................. 21
~DISASSEMBLY~ .............................. 10
[I] Feed timing adjustment ........................ 21
0 Presser height adjustment ..................... 21
OJ Cover.................................................... 10
[I] Synchronizer adjustment ...................... 22
I1J Presser.................................................. 10
[I] Rotary hook ......................................... II
[]] Thread trimmer ~djustment .................. 23
[I] Tension release lever adjustment .......... 24
0 Thread trimmer .................................... II
[!] Thread wiper adjustment...................... 24
[I] Feed. mechanism (8706/ 8707) .............. 12
[]] Automatic presser foot lifter adjustment
[I] Feedmechanism(8714/B716j8747) .... 13
( -900; electromagnetic type) ............... 24
[]] Needle bar mechanism ......................... 13
~TROUBLESHOOTING GUIDE~... 25
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[I] Upper shaft and needle bar mechanism
I. When the pulley 0 turns in the direction indicated by the arrow, the movement is transmitted to the upper shaft
8 and causes the counter weight 8 to turn.
2. The movement is transmitted to the needle bar connecting rod 8 via the needle bar crank 8 connected to the
counter weight.
3. The needle bar 8 connected to the needle bar clamp 8 is moved up and down.
4.
The needle bar is guided by needle bar bushing U 0 and needle bar bushing D 0.
[I] Lower shaft and rotating hook mechanism
I. When the pulley 0 turns in thedirection indicated by the arrow, the movement is transmitted by the upper shaft
bevel
gear 8 mounted to the upper shaft 8 to vertical shaft bevel gear U8 mounted on the top of thevertical
shaft G.
2. The movement is then transmitted by vertical shaft bevel gear D 8 mounted on the bottom of the vertical shaft
8 to the lower shaft 0 via the lower shaft bevel gear 8.
3. The rotary hook 0 is then caused to rotate in a full circle by the lower shaft 0.
-I-
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[I] Feed mechanism (8714/8716/8747)
•
---
----
_...---
----
I. When the pulley 0 turns in the direction indicated by the arrow, vertical movement is transmitted by the feed
cam 8 mounted
to the upper shaft 8 to the forked connector 8 via the feed cam sleeve G.
2. The horizontal feed rocker arm 8 connected to the forked connector 8 is then moved in a circular arc.
3. The feed
bar 8 is moved back and forth by the horizontal feed bar shaft 0 mounted to the horizontal feed
rocker shaft
8.
4. The crank rod fi) is moved up and down by the feed cam 8.
5. The horizontal feed shaft & connected to the crank rod ~ is then moved in i circular arc.
6. The horizontal feed arm Cl connected to the feed shaft & is also moved in a circular arc.
7. The movement of the feed dog mounted to the feed bar 8 is determined by thecombined action of steps 3and6.
-2-
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. ~
(}] Feed mechanism (8706/8707)
I. When the pulley 0 turns in the direction indicated by the arrow, the level feed connecting rod 8 is moved up
and down by the level feed eccentric wheel 8 mounted to the upper shaft f).
2. The feed rocker shaft arm 0 is moved in a circular arc by the level feed arm link assembly 0 mounted to the
level feed connecting rod 8.
3. The feed bar 0 is moved back and forth by the wick hanger 0 mounted to the feed rocker shaft f).
4. The vertical feed connecting rod 6) is moved up and down by thevertical feed eccentricwheel Gi) mounted to the
upper shaft f).
5. The feed lifting rocker shaft arm • is moved in a circular arc by the vertical feed connecting rod 6).
6. The feed bar 0 is moved up and down by the feed lifting arm 4D mounted to the feed lifting rocker shaft G) .
7. The movement oft he feed dog G) mounted to the feed bar 0 is determined by the combined action of steps 3 and
6.
-3-
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[!] Lubrication mechanism
1. Upper shaft oil supply
Upper shaft
(I) The oil from the pump 8 passes through upper shaft bushing M 8, enters the center of the upper shaft, and
from there is supplied to upper shaft bushing L 8 and upper shaft bushing R 8.
The oil dispersed in the arm column is supplied to the feed adjuster.
(2) An oil adjusting valve 8
is provided at the left end of the upper shaft, and oil is supplied to the thread take-up
arm via the counterweight and needle bar crank.
(3) Felt
is mounted on the needle bar crank in order to prevent excess oil discharge or oil clogging, and oil is
supplied to the needle bar connecting rod.
(4) The oil
that accumulates in the thread take-upshield is supplied to the needle barO and needle bar bushings U
and D via the oil wick 8.
(5) The oil is held inside by the rubber stopper 8 in the pulley presser screw at the right end of the upper shaft.
(6)
The oil that accumulates at the dip in the arm is drawn back to the pump 8 via a felt and a tube.
-4-
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2. Lower shaft oil supply
Lower shaft
(I) The oil is supplied by the pump to the lower shaft and lower shaft bushing L f).
(2) Part of the oil from lower shaft bushing L f) flows through the lower shaft to the rotary hook.
Also, the oil ejected from lower shaft bushing L f) is supplied to the horizontal feed rocker shaft 0 and the
vertical feed shaft 8 via a wick.
(3)
The oil dispersed in the ar.,m column is supplied to lower shaft bushing R 0, the horizontal feed rocker shaft
0, and the vertical feed shaft 8 via the arm channel.
3. Pump mechanism
When the vanes at the bottom of the vertical
shaft turn, the centrifugal force sucks the oil up
through the hole in the center. The oil is then
expelled from the outlets at the ends of the spinal
chambers to the various oil tubes.
In addition, a plunger pump attached to the
pump body draws oil which accumulates in the
dip in the arm back to the pump.
-5-
----Pump body
____ Rotating
vanes
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(}] Thread trimmer mechanism
1.Thread trimmer mechanism
As shown in the illustration, the thread trimmer
mechanism consists
of the movable knife 0, the
fixed knife
0. a lower thread finger 8. the
movable knife holder G. the knife holder
assembly
8. the trimmer forked shaft 8. the
trimmercam leverassembly
8, the trimmer cam
0, and the trimmer solenoid 8.
2. Operation ofthetrimmermechanism(Thefollowing illustrations are with the high-speed rotating
hook removed.)
(I) Condition during high-speed operation
* Because the trimmer cam lever assembly 8 is kept pressed toward the trimmer'solenoid 8 by the cam lever
return spring
f), the trimmercam lever assembly 8 does not engage with the trimmer cam 0 and the movable
knife holder 8 does
not function. ,.
In addition, the trimmer lever 8 is pressed by the trimmer leverspring CD so that the movable knife holder8
does not move.
(2) Condition when a trim signal
is input
* When the foot Pedal is depressed again and the trim signal is input, thetrimmersolenoid 8 pushes the trimmer
cam lever shaft
G). The roller shaft (right side) of the trimmer cam lever assembly 8 that is connected to the
trimmer
cam lever shaft G) moves around the outside of the trimmer cam 0.
-6-
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(3) Movement of the trimmer holder
* When the lower shaft turns and the trimmer cam 0 pushes the roller shaft (right side) upward, the movement is
transmitted to the trimmer forked shaft 8 via the trimmer cam lever assembly 8.
* The movement is transmitted to the trimmer connecting rode and the movable knife holder 8 via the trimmer
lever 0 mounted to the trimmer forked shaft 8.
* The movable knife 0 mounted to the movalbe knife holder 8 moves in thedirection indicated by the arrow and
overlaps with the fixed knife 8.
(4) Trimming completion and stop
* When the trim signal stops, t'he trimmer solenoid 8 returns, the trimmer cam leverassembly 8 is pushed by the
cam lever return spring G), and the toller shaft oft he trimmer cam leverassembly8 separates from the trimmer
came.
* The trimmer connecting rod fD and the movable knife holder 8 are returned to their original positions (in the
directions indicated by the arrows) by the trimmer lever spring CD.
(5) Thread trimmer safety device
0
* Ifthe moving knife 0 does not return to its original position, the return pin (left side) of the trimmer cam lever
assembly 8
and the trimmer cam 8 function to return the movable knife 0 to a position where it will not come
in contact with the needle.
-7-
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----~~
---
(I) The needle rises to a point 2.2 mm above the
lowermost point and the tip
of the rotary hook the
loop formed by the needle.
(2)
The trim signal is input. and the trimmer cam
causes the movable knife to move. The needle
thread
is caught by the rotary hook and passes
through the inner hook.
Bobbin thre~~
~ Movable knife
~ Needle thread
I
I
'
Fixed knife r
(3) The tip of the movable knife goes into the triangular loop formed by the needle and bobbin threadsdivided by
the tip
of the rotary hook at the needle hole plate, and spreads the needle and bobbin threads.
At this time, the thread take-up is slightly above the lowermost position and the needle thread is separated by
the movable knives
as shown in the illustration.
If the timing for the above operation is too early. it will affect the loop spreading of the movable knives and
errors in thread trimming may occur. ·'
Needle thread
(4) The needle and bobbin threads hooked by the movable knife in step (3) are spread out to a fan shape by the
shape
of the knife. and as they are spread out gradually by the thread spreader, they are cut by the tip of the
fixed knife.
At this time, the thread take-up
is almost at the uppermost position.
At the same time
that the knife is spreading out the thread, the tension release lever functions to let the needle
thread
out smoothly and prevent excessive slack.
Note
that the amount of thread determined at the movable knife becomesthe length of thread remainingfor the
needle thread
and in the bobbin case after thread trimming, and this in turn influences the composition of the
stitch the next time sewing
is begun.
-8-
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11] Thread tension release lever
mechanism
(8707 /8716/8747)
* When trim signal is input. the trimmer solenoid 0
functions. the tension release plate 8 pushes the
tension release
bar 8 via the tension release lever
8 and the tension release wire 0 and opens the
tension disc.
When the needle upper stop signal is input, current
no longer flows to the thread trimmer solenoid, and
the tension disc closes.
[!] Quick-back mechanism
0
•
•
* When the quick-back switch is pressed, the reverse
solenoid 0 functions. the solenoid lever plate 8
is
pulled via the solenoid lever 8 and the connecting
link
0. and the reverse lever 8 is pulled
downward.
While the quick-back switch remains pressed, the
machine does reverse stitching. When
the switch is
released, it is returned to its original position by a
return spring and the machine resumes forward
stitching.
[I] Thread wiper mechanism
(8707 /8716/8747)
* When the needle upper stop signal is input, there is
a delay of 85 ms, and then the solenoid 0
functions. the thread wiper lever 8 moves the
thread wiper 8 via the grooved link 0. and the ·
neelde thread is wiped on top of the material after
thread trimming.
When
the current stops flowing to the solenoid, the
thread wiper is returned to its original position bya
spring.
[!] Automatic presser lifter mecha-
nism
* When the power switch is turned on, the presser
lifter solenoid 0 functions
(ON) and the knee lifter
presser
bar 8 is pressed upward via the presser
lifter link
8.
* When the upper part of the foot pedal is depressed
lightly,
the presser lifter solenoid 0 becomes OFF,
the presser lifter link 8 returns, and the presser
drops back down.
-9-
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CDISASSEMBLY -~
I. Loosen the set screw 8 and remove the needle G. (Loosen the set and remove the thread wiper.)
2. Remove the three screws 0. and then remove the face plate 8 and the packing 0.
3. Remove the five screws 0 and then remove the side cover 0.
4. Remove the two screws 0. and then remove the oil stopper plate 0.
5. Remove the oil cap Gi) and the oil cap CD.
6. Loosen the set screw CB and remove the tension regulator assembly •.
7. Remove the slide plate e.
8. Remove the two screws 6'. and then remove the needle plate 48.
II) Presser
I. Loosen the two set screws 8 and remove the feed dog G. (Use the presser lifter lever to raise the presser
assembly.)
2. Loosen the set screws 0
and remove the presser foot 8. (Remove the screw, and then remove the thread wiper
holder.)
3. Remove the screw
8. and then remove the presser spring bar O. the presser spring 8. and the washer 0.
4. Loosen the set screw 0 and remove the presser bar clamp fl).
5. Remove the presser bar CD by extracting it from the top of the arm.
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!"'.,
[I) Rotary hook
f)
~~~"L,..~~-·
r---"\:'~·
l. Tilt the machine.
2. Remove the bobbin case 0.
3. Remove the screw f). and then remove the rotary hook position bracket.
4. Loosen the three set screws G
and remove the rotary hook 0.
[I] Thread trimmer
I.
2.
3.
4.
5.
6.
7.
8.
9.
10.
II.
12.
13 .
0
f)
Remove the screw 0. and then remove the fixed knife f).
Push the thread trimmer connecting rod 0 in the direction indicated by the arrow, and then position the two
screws G where they
can be seen.
Remove the screws
0. and then remove the movable knife 0.
Remove the screw 8. and then remove the lower thread finger 0.
Remove the screw 0 on the thread trimmer lever 0 side.
Remove the bolt
41). and then remove the knife holder assembly 0. the movable knife holder fl, and the
trimmer connecting rod 0.
Remove the trimmer lever spring G).
Remove the screw e. and then remove the thread tension lever fl.
Remove the screw ~. and then remove the trimmer solenoid CD.
Move the trimmer cam leverassembly Gil in the direction indicated by the arrow, and then remove the stop ring
41.
Loosen the set screw G), and then remove the trimmer cam lever shaft f) toward the right side (the trimmer
solenoid side).
Remove the collar
fi, the cam lever return spring fJ, the trimmer cam lever assembly e.the washer f), and
the cushion fJ.
Remove the screw f), and then remove the trimmer lever 0. the trimmer leverspringfl), and the forked shaft
••
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[I] Feed mechanism (8706/8707)
I. Remove the wick 0.
2. Loosen the two set screws 0 on the right side of the feed lifting rock shaft 8, and then remove the collar 8.
3. Loosen the two set screws 8 on the feed lifting rock shaft arm 8 and the three set screws 0 on the feed lifting
arm 8.
4. Tap wedges into the notches oft he feed lifting rock shaft arm 8 and thefeed lifting arm 8, and then removethe
feed lifting rock shaft 8
toward the left side. (The oil rejector 8 and the feed lifting arm 8 will also comeoff.)
5. Loosen the two set screws CD on the right side of the feed rock shaft G), and then remove the collar •.
6. Remove the wick fD from the feed bar arm G).
7. Loosen the set screw e on the feed rock shaft arm • and the two set screWS·"· on the feed bar arm G).
8. Tap wedges into the notches in the feed rock shaft arm Cl and the feed bar arm G), and then remove the feed
rocker shaft j toward the left. (The oil rejector
fD and the feed bar arm G) will also come off.)
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[II Feed mechanism (8714/8716/8747)
I. Loosen the nut 0. and remove the screw 8.
2. Remove the two set screws 8. and remove the oil stopper G.
3. Loosen the set screw 8, rotate the taper pin 8. and removethe feed lifting rockshaft8 and feed lifting arm 0.
4. Loosen the set screw 8. and remove the feed arm pin GD.
5. Remove the two set screws G), and remove the oil stopper 48.
6. Loosen the set screw 8. disconnect the taper pin fD, and remove the feed rockshaft fl,feed rock shaft arm tD.
and feed bar 8.
[!] Needle bar mechanism
Needle bar
bushing U
I. Tilt the machine.
•
•
•
•
2. Remove the needle bar thread guide G.
3. Remove the wick 8 from the top of the needle bar bushing U.
4. Loosen the set screw 8. and remove the needle bar 8. and needle bar clamp 8. (Remove the slide block.)
5. Remove the oil cap
8. loosen the set screw 8 and remove the thread take-up support pin 0.
6. Remove the oil cap and loosen thetwo set screws 8. Now remove the thread take-up rocking arm GD. needle bar
crank G), needle bar connecting rod CJ, and wahser e.
-13-
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~ ASSEMBLY )
[I] Needle bar ••
Reference
J~t
lines
~~ /·-=
Line
Screw flat
B706 DA x 1 DB X 1
B707 DA X 1
DB X 1
B714 DA X 1
DB X 1
B716 DA X 1
DB X 1
B747
DB X 1
----
I. Install the thread take-up arm assembly 0. the needle bar crank f), the needle bar connecting rod 0. and the ~
washer 8 with the set screw 8. '-___/
* Refer to the above illustration for the position of the needle bar crank f) screw flat.
2.
Thread the wick through the thread take-up lever support shaft 8. (Refer to the illustration.)
3. Fit the thread take-up lever
support shaft 8 through the thread take-up arm assembly 0. and then secure it
with the set screw
8.
4. Fit the block 0 into the groove, and then fit the needle bar clamp 8 through the neelde bar connecting rod 0
and the block 0.
(Fit the block into the groove with the chamfered side toward the inside.)
5. Fit the needle
bar 0 into needle bar bushing U fD from the top. and then pass it through the needle bar clamp
••
6. Pass the wick through from needle bar bushing U fD. (Refer to the illustration.)
7. Turn the pulley and set the needle bar to the lowermost position.
8. Align the second reference line from the
bottom on the needle bar fD with the bottom end of needle bar bushing
oe.
@Threading the wicks
( l) Thread the wick through the thread take-up arm
assembly 8.
(2) Thread the wick into the machine while installing
the thread take-up
arm assembly 8.
(3) Insert a length of piano wire into the oil hole and
pull out the wick as shown in the illustration.
(4) Align the end
of the wick with the edge of the
thread take-up
arm assembly 8 and insert the rest
of the wick into the oil hole.
Piano wire
Wick
(I) Thread the wick through the upper end of the
needle
bar bushing.
(2) Manually
turn the pulley and set the thread take-
up to the uppermost position.
(3) As shown in the illustration, insert the wick until
it
contacts the top of the thread take-up arm
assembly 0.
(4) Insert the end of the wick into the oil hole.
-14-
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II] Feed mechanism (8706/8707)
•
~
I
I
I
I•
Feed dog
I. Install the needle plate 0 with the screws 8.
2. Tilt the machine.
•
•
•
3. Mount the feed lifting rock shaft 8 (from the left side), the feed lifting arm 8. the oil rejector 8. and the feed
lifting rock shaft
arm 8.
4. Mount the set collar 0 onto the feed lifting rock shaft 8. and then secure it with the screw 8 so that it moves
easily with no play.
5.
Connect the wick 8 to feed lifting rock shaft 8. (Refer to the illustration below.)
6. Fit the forked part of the feed bar f1 onto the roller on the end of the feed lifting arm 8.
7. Mount the feed rock shaft e(from the left side), thefeed bar arm$. the oil rejector G), and the horizontalfeed
rock shaft
arm 41.
8. Fit the feed rock shaft 4D into theset collar 0. and thensecure it with thescrew8 so that it moveseasily with no
play.
* Secure the feed rock shaft·arm 4D with the screw 41 in a position where the level feed arm link assembly moves
easily.
* Secure the feed lifting arm 8 and the feed bar arm $ with the screws fD in a position where the feed dog G)
divides the groove in the needle plate 0 front to back and left to right. In addition, tighten the screw CD so that
the feed dog G) projects I mm out of the needle plate 0.
9. Connect the wick 8 to the feed lifting rock shaft 8. (Refer to the diagram below.)
* Secure the feed lifting rock shaft arm 8 with the screws G) in a position where the vertical feed connecting rod
fJ) moves easily.
Ql)--
-15-
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II] Feed mechanism (8714/8716/8747)
~
1
I
I
I•
•
Feed dog
I. Install the needle plate 0 with the screws 8.
2. Tilt the mac}line.
3. Mount the taper pin 8 onto the arm bed.
4.
Mount the feed dog 8 onto the feed bar 8 with the screws 8.
1/ 1/
•
•
G
5. Secure the feed rock shaft 8. the feed rock shaft arm O. and the feed bar 8. with thesetscrew f) so that they
move easily with no play
on the taper pin 8. (At this time,adjust thefeed dog 8 so that it divides thegroovein
the
throat plate into left and right.)
6. Fit the forked shaft 0 into the forked part of the feed rock shaft arm 0. and then secure the feed rock shaft
arm pin 4D with the set screw Q).
7. Mount the oil stopper fl with the screws CJ).
8. Mount the taper pin $ onto the arm bed.
9.
Mount the feed lifting rock shaft 8 and the feed lifting arm Cl with the set screw G) so that they move easily
with not play
on the taper pin $.
10. Fit the side block G) of the feed lifting arm C1 into the forked part of the feed bar 8. and then confirm that it
slides easily.
II. Fit the screw fJ) into the crank rod fD and the feed lifting rock shaft fl, and then secure it with the nut 8.
12. Install the oil stopper fl with the screws fl.
13. Turn the pulley and loosen the screw fa to adjust the feed dog 8 so that it extends I mm out of the top ofthe
needle plate.
14. Set the length control dial to the highest setting and turn the pulley.
15. Loosen the screw fa and adjust the feed rock shaft 8 so that the feed dog 8 divides the groove in the needle
plate in
half front to back.
-16-
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fl] Thread trimmer
I. Fit the forked shaft 0 into the arm bed.
2. Mount the collar 8. the cam lever return spring 8. the trimmer cam leverassemblyG. the washer8 and the
cushion 8 onto the arm bed, and then mount the trimmer cam levershaft8 (after fitting the slide block 8 of
the trimmer cam lever assembly 8 into the fork of the forked shaft 0).
3. Fit the stop ring 0 onto the trimmer cam lever shaft 8.
4. Tighten the set screw ~.
5. Mount the thread trimmer solenoid 4D to the arm bed with the screw $.
Mount the solenoid so that the gap between the trimmer cam lever shaft 8 and the solenoid lever G) on the
trimmer solenoid CD is as small as possible.
6.
Mount the tension releasing lever CD with the screw 48. (Refer to p.23 for instructions on adjusting the tension
releasing lever.)
7.
Mount the movable knife holder 4D onto the arm bed, and then mount the knife holderassembly 41 (and then
trimmer connecting rod 8> with the bolt Cl).
8. Mount the trimmer lever spring~ and the trimmer lever fJ onto the forked shaft 0 and securethem with the
screw fl.
9. Mount the thread trimmer connecting rod 8 to the thread trimmer lever fJ with the screw tl.
10. Mount the lower thread finger fJ to the arm bed with the screw fi.
II. Mount the fixed knife f) to the arm bed with the screws fi.
12. Mount the movable knife f1 to the movable knife holder 4D with the screws 1).
13. Hook the trimmer lever spring~ onto the trimmer lever fl.
14. Confirm that the position of the trimmer cam is correct.
* Move the lower thread finger fJ towards the movable knife in order to maintain the space between it and the
rotary hook.
-17-
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~ Thread trimmer timing adjustment
I. Thread trimmer cam position adjustment
* Turn the pulley, and then when the needle bar rises 5 mm
above the lowermost position, press the thread trimmer
solenoid CD and adjust the thread trimmer cam G) so that
the roller shaft contacts the cut out part of the thread
trimmer cam G) and the end of the cam and the end of the
roller shaft
is 0.6 to 0.8 mm when the thread trimmer cam
lever assembly returns.
2. Fixed knife and moving knife position adjustments
* The end of the fixed knife e and the blade of the movable
knife e must be in the position shown in Fig. A when
the
roller shaft of the thread trimmer cam lever assembly 0
moves up the thread trimmer cam G). (The mating mark on
the movable knife holder fD must be in alignment with the
mating mark on the kpife holder assembly $).
If the positions do not agree with those in Fig. A. move the
thread
trimmer lever fJ) and tighten the screw f) so that the
end
of the fixed knife e and the blade of the movable knife
e agree with the position in Fig. A when the roller shaft
moves
up the thread trimmer cam G).
[!] Rotary hook
Bottom of the needle bar bushing
•
41
~
em]
""
-.....
Reference -
lines -
-:
--
-
~j
~·[;
Lower shaft fJ
-
B706 DA X 1 DB X 1
B707 DA X 1
DB X 1
~~;~re
·,~>'o ~ •
B714 DA X 1 DB x 1
B716 DA X 1
DB X 1
B747 DB X 1
~
•
I. Mount the needle plate.
2. Mount the rotary hook 0 onto the lower shaft 0 and secure it with the screw 8.
3. Mount the rotary hook position bracket 0 with the screws 8.
1-1.5 mm
•
4. Mount the needle bar thread guard 8 onto the needle bar, and then secure the needle 8 with the set screw 8.
5. Turn the pulley so that the needle bar rises from the lowermost position and align the needle bar reference line
with the
bottom of the needle bar bushing as shown in the illustration.
6. Align the
rotary hook point with the center of the needle 8.
At this time, adjust so that the distance between the rotary hook point and the upper edge of the eye of the needle
is 0 to 0.5 mm and the distance between the needle 8 and the rotary hook tip is 0.05 to 0.1 mm.
7. Mount the needle plate.
8.
Mount the slide plate C).
9. Adjust the feed timing.
Turn the pulley forward and adjust so that the tip of the needle is aligned with the upper surface of the needle
plate when the feed
dog finishes the feed and begins to retract and the tip of the feed dog is aligned with the upper
surface of the needle plate. (Refer to the timing adjustment on p.21.)
* Confirm that the gap between the rotary hook position bracket 0 and the rotary hook 0 is just enough for the
thread being used to pass through easily.
-18-
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