Brother LH4-B800E Service Manual page 24

e
5. The lower thread trimmer cam connecting rod q is connected to lower thread trimmer link A w, so that the
movement of the lower thread trimmer cam connecting rod q is transmitted via lower thread trimmer link A w and
the lower thread trimmer connecting rod e to the knife driving lever r.
6. The collar y that is installed to the lever t is linked to the cam groove in the knife driving lever r, so that when
the knife driving lever r operates, the lever t rotates centering on the screw u.
7. The lower thread retainer i is secured to the lever t, so the lower thread retainer i starts to operate.
8. When the lower thread retainer i operates, the collar !0 that is installed to the lower thread clamp plate o moves
over the ridge line of the cam of the lower thread retainer i, and the lower thread retainer i starts to close and
engages with the lower thread presser !1 so that the lower thread is clamped.
9. The lower thread retainer i then continues operating.
10. The fixed knife !2 is secured to the knife driving lever r, so that when the knife driving lever r operates, the cam
section of the movable knife ! 3 that is secured to the fixed knife ! 2 moves over the cam section of the base plate
!4 so that the movable knife !3 starts to close. When the lower thread retainer i has finished operating, the
movable knife !3 meshes fully with the fixed knife !2 and cuts the lower thread.
r
q
w
LH4-B800E
1. MECHANISM DESCRIPTION
i
u
t
y
r
i !1
o
!0
!3
!4 !2 r
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