English
Reactive Forces
The most common reactive forces that
occur during cutting are: kickback,
pushback and pull-in.
Dangers of kickback
Kickback can result in
serious or fatal injury.
Kickback occurs when the saw is
suddenly thrown up and back in an
uncontrolled arc towards the operator.
6
Kickback occurs, e.g.
when the upper quadrant of the bar
–
nose unintentionally contacts wood
or another solid object, e.g. when
another limb is touched accidentally
during limbing.
when the chain at the nose of the
–
guide bar is pinched in the cut.
Quickstop chain brake:
This device reduces the risk of injury in
certain situations – it cannot prevent
kickback. If activated, the brake stops
the saw chain within a fraction of a
second – for a description of this device
refer to chapter on "Chain Brake" in this
manual.
To reduce the risk of kickback
Work cautiously and avoid
–
situations which could cause
kickback.
Hold the saw firmly with both hands
–
and maintain a secure grip.
Always cut at full throttle.
–
Be aware of the location of the guide
–
bar nose at all times.
Do not cut with the bar nose.
–
Take special care with small, tough
–
limbs, they may catch the chain.
Never cut several limbs at once.
–
Do not overreach.
–
Never cut above shoulder height.
–
Use extreme caution when re-
–
entering a previous cut.
Do not attempt plunge cuts if you
–
are not experience in this cutting
technique.
Be alert for shifting of the log or
–
other forces that may cause the cut
to close and pinch the chain.
Always cut with a correctly
–
sharpened, properly tensioned
chain – the depth gauge setting
must not be too large.
Use a low kickback chain and a
–
narrow radius guide bar.
Pull-in (A)
Pull-in occurs when the chain on the
bottom of the bar is suddenly pinched,
caught or encounters a foreign object in
the wood. The reaction of the chain pulls
the saw forward – always hold the
spiked bumper securely against the tree
or limb.
MS 251, MS 251 C
A