Brother Db2-b714-3 Instruction 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...

[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]...

[I] Feed mechanism (8714/8716/8747) 
• 
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_...--­----
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...

. ~ 
(}] 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...

[!] 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....

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...

(}] 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 
trimmer  cam lever  assembly 
8, the trimmer cam 
0, and the  trimmer  solenoid 8. 
2. Operation  of the  trimmer  mechanism(The  following illustrations  are with  the high-speed  rotating 
hook...

(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 the  direction  indicated  by the arrow and...

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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 threads...