ICFR – Chainsaw Safety and Operating Handbook
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14. Silencer/muffler
The silencer reduces engine noise, directs exhaust
emissions away from the operator and is normally
fitted with a spark arrestor to reduce the risk of
starting a fire.
15. Guide bar
The guide bar supports and guides the saw chain. Refer
to section 14.2 for further details.
16. Guide bar nose/tip
The guide bar nose/tip is normally fitted with a friction
reducing nose sprocket.
17. Saw chain
The saw chain performs the actual cutting.
It is made
up of different components. Refer to section 14.1 for
further details.
18. Bumper spike/felling dog
The bumper spike/felling dog is a toothed or smoothed
stop for holding the chainsaw steady against the timber
to be cut, thus facilitating ease of cutting. It also
protects the muffler and chain lubricant tank.
19. Chain catcher
The chain catcher reduces the risk of injury to the
operator when the saw chain breaks or comes off
the guide bar.
20. Clutch/sprocket cover
The clutch/sprocket cover protects the clutch and
chain drive sprocket. It also clamps the guide bar
securely in place. The chain brake mechanism may be
incorporated into the clutch/sprocket cover.
21. Rear hand guard
The rear hand guard protects the operator’s right
hand if the saw chain breaks or comes off the guide
bar.
22. Decompression valve
The decompression valve reduces engine compression
making for easier starting. It is not fitted on all
chainsaw makes and models.
23. Chain tensioner
The chain tensioner permits precise adjustment of the
chain tension. The chain tensioner could be fitted in a
different position on the chainsaw depending on the
make and model.
Chainsaw makes/models fitted with inertia activated
chain brakes are considered safer to use, especially
when making horizontal felling or bore cuts or when
debranching (in working situations where the chain
brake may not be activated manually).
The front hand guard also protects the operator’s
hand from injury that could be caused by branches
and accidental contact with the saw chain should the
operator’s hand slip off the front handle.
4. Starter cover
The starter cover contains the starter mechanism and
covers the flywheel and ignition module. The cover
also has slots for important cooling air induction.
5. Chain lubricant tank and filler cap
6. Starter grip
To start the chainsaw the starter grip is pulled.
7. Air filter cover
The air filter cover protects and secures the air filter
in position as well as reducing air induction noise. It
could be part of the top cover or a separate cover.
8. Throttle control trigger
The throttle trigger is used to control the engine speed.
9. Throttle lockout/palm lock
To prevent accidental acceleration, the throttle
lockout must be depressed before the throttle control
trigger can be activated.
10. Choke control
The choke is activated for cold starting. It may
incorporate a start throttle lock which automatically
locks the throttle control trigger in the correct position
once the choke has been activated.
11. Rear handle
The rear handle supports the operator’s right hand. It
houses the throttle trigger and throttle lockout/palm
lock.
12. Stop switch or ignition on/off switch
The stop switch must be accessible to the operator’s
right hand thumb for emergency switch off.
13. Fuel tank and filler cap