Makita UC3020A Technical Information page 5

R
epair
[3] DISASSEMBLY/ASSEMBLY
[3] -2. Brake Mechanism and Armature
Principle of Brake Mechanism
Refer to the explanation below when repairing Brake mechanism.
These models are equipped with the following two brake systems.
A. Brake Synchronized with Switch Lever
This brake works when Switch lever is released to stop operation. (Figs. M-1, M-2, M-3)
B. Kick Back Brake
This brake works when Front hand guard is pushed towards Chain bar. The machine stops even if Switch lever stays
in ON position. (Fig. M-4)
Fig. M-1
Before Pulling Switch Lever
Link plate complete
Fig. M-2
When Switch Lever is Pulled
Brake band
Brake band is also pulled to unlock the drum portion
of Armature, and Armature starts rotating.
Fig. M-4
Kick Back Brake
projection on
Front hand guard
Link plate complete
1) When Front hand guard is pushed towards Chain bar, Link plate complete is bent by the projection on the guard.
2) Brake band is pulled by the bent Link plate complete. (The tension force of Compression spring 9 keeps Link plate
complete bent.)
3) The drum portion of Armature is locked by Brake band to stop the rotation of Armature.
Brake mechanism viewed from the Housing (R) side
projection on
Front hand guard
Compression spring 9
Brake band
drum portion Switch lever
of Armature
Compression spring 9
Brake band
drum portion
of Armature
Rod
Fig. M-3
When Switch Lever is Released
Brake band returns to the initial position to lock
the drum portion of Armature, and Armature immediately
stops rotating.
drum portion of Armature
P 5 /10
Switch Lever
Switch lever
in ON position