Stihl MSA 160.0 C Notice D'emploi page 11

6 Kickback and Other Reactive Forces
personal injury in the event of a thrown or bro‐
ken chain.
► Never operate the chain saw with a dam‐
aged or missing chain catcher.
■ Contacting foreign objects while sawing might
cause the chain to break or be thrown, or
cause the chain saw to propel dangerous deb‐
ris or kick back in the direction of the operator.
To reduce the risk of severe or fatal personal
injury caused by contact with foreign objects:
► Inspect the tree, log or branch before cut‐
ting.
► Remove any foreign objects to ensure that
the wood is free of materials such as nails,
spikes, cables, or wires.
► Before starting a cut, ensure that it can be
completed without contacting surrounding
objects or structures such as fencing or
stonework.
■ Check the chain and guide bar at regular short
intervals during operation, or immediately if
there is a change in cutting behavior:
► Switch off the motor, activate the chain
brake and remove the battery.
► Check the condition and tension of the
chain. Look for damage to the chain or
guide bar.
► If the chain cannot be properly tensioned,
or if other components of the saw are worn
or damaged, stop work immediately and
take your chain saw to an authorized STIHL
servicing dealer for inspection, repair or
maintenance.
DANGER
■ To reduce the risk of electrocution:
► Never operate this chain saw in the
vicinity of any wires or cables that
may be carrying electric current.
► Never cut near power lines.
► Do not rely on the chain saw's insu‐
lation against electric shock.
6 Kickback and Other Reac‐
tive Forces
6.1 Reactive Forces
WARNING
■ Reactive forces may occur any time the chain
is rotating. Reactive forces can cause serious
or fatal personal injury.
■ The powerful forces used to cut wood can be
reversed and work against the operator. If the
rotating saw chain is suddenly and signifi‐
cantly slowed or stopped by contact with any
0458-024-8201-A
solid object such as a log or branch, or is
pinched, the reactive forces may occur
instantly.
■ These reactive forces may result in loss of
control, which, in turn, may cause serious or
fatal injury.
► An understanding of the causes of these
reactive forces may help you avoid the ele‐
ment of surprise and loss of control. Sur‐
prise contributes to accidents.
The most common reactive forces are:
– Kickback
– Pull-in
– Pushback
6.2 Kickback
6.2.1 Kickback
WARNING
Kickback may occur when the moving
chain near the upper quadrant of the
bar nose contacts a solid object or is
pinched.
■ When this occurs, the energy driving the chain
can create a force that moves the chain saw in
a direction opposite to the chain movement at
the point where the chain is slowed or stop‐
ped. This may fling the bar up and back in a
lightning fast reaction mainly in the plane of
the bar and can cause severe or fatal injury to
the operator.
■ Kickback may occur, for example, when the
chain near the upper quadrant of the bar nose
contacts the wood or is pinched during limb‐
ing, or when it is incorrectly used to begin a
plunge or boring cut.
■ The greater the force of the kickback reaction,
the more difficult it becomes for the operator to
control the chain saw. Many factors influence
the occurrence and force of the kickback reac‐
tion. These include chain speed, the speed at
which the bar and chain contact the object, the
location and angle of contact, the condition of
the chain, and how quickly the chain is slowed
or stopped, among other factors.
English
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