Upper Thread Trimmer Mechanism - Brother LH4-B800E Service Manual

3-12. Upper thread trimmer mechanism

Apply grease to q
i
t r
!6
!7
!5
!4
!3
!2
i
u
@1
!9
!8
@0
Align edges
Insert the upper thread trimmer fulcrum shaft q into the arm. Secure the upper thread trimmer fulcrum shaft q with the set screw collar
assembly w so that it turns smoothly. Install the rubber cap e from the top of the arm.
Install the spring hook plate r to the upper thread trimmer lever assembly y with the screw t. Attach the spring u to the stop plate i as
shown in the illustration. Install the back plate o and the stop plate i to the upper thread trimmer lever assembly y with the two collars
! 0 and the two screws ! 1 . Apply grease to the sliding surfaces.
Install the support stud !2 to the setting plate !5 with the nut !3 and the plain washer !4 . Install the setting plate !5 to the upper thread
trimmer lever assembly y with the screw ! 6 and the plain washer ! 7 .
Press-fit the longitudinal feed arm pin ! 8 onto the longitudinal feed arm ! 9 . Secure it by tightening the set screw @ 0 . Install the bolt @ 1 . Place
the longitudinal feed arm roller @ 2 onto the longitudinal feed arm pin ! 8 and secure it with the two retaining rings @ 3 . (Longitudinal feed arm
assembly)
Install the eye bolt @4 to the trimmer driving arm @5 . Install the roller shaft @6 to the support plate @9 with the nut @7 and the spring washer
@ 8 . Place the driving arm roller # 0 onto the roller shaft @ 6 . Secure the driving arm roller # 0 with the retaining ring # 1 . Install the support plate
@9 and the stopper #2 to the trimmer driving arm @5 with the eye bolts #3 and the plain washers #4 . (Trimmer driving arm assembly)
Install the upper thread trimmer lever set # 5 to the upper thread trimmer fulcrum shaft q with the two washers # 6 and shoulder screws # 7 .
Place the roller #8 onto the support stud !2 of the upper thread trimmer lever set #5 , and then place it into the groove in the presser roller
bracket # 9 .
Pass the longitudinal feed arm pin ! 8 of the longitudinal feed arm assembly $ 0 through the upper thread trimmer lever set # 5 , and
provisionally install it to the trimmer driving lever $1 with the eye bolt @1 . Provisionally install the trimmer driving arm assembly $2 to the
trimmer driving lever $ 3 with the eye bolt @ 4 .
Turn on the power. After the mechanism moves to the home position, press the RESET key to lower the presser foot.
Tighten the eye bolt @ 1 of the longitudinal feed arm assembly $ 0 so that the slot of the upper thread trimmer lever set # 5 and the edge of the
washer #6 are aligned. Tighten the eye bolt @4 so that the stop plate i and the stopper #2 are in the positions shown in the illustration.
Attach the two springs $4 to the upper thread trimmer lever set #5 . Attach the larger hooks of the springs $4 to the pins $5 on the arm.
e
@4
w
q
y
u
!1
!0
o
#7
#6
Apply grease to @2
@3
@2
@5
#1
@6
Apply grease to #0
#0
#2
@9
#4
@8 #4
#3
#3
@7
#5
Apply grease to #7 and #8
@1
@4
$1
$3
$0
$2
#5
!8
LH4-B800E
#6
#2
i
#8
#9
!2
3. ASSEMBLY
#5
Aligned
Approx. 1 mm
$5 $4
#5
3 - 21