In order to keep control of your saw, always maintain a
firmfoothold.Neverworkonaladder,inatreeoronany
other insecure support. Never use the saw above
shoulder height (fig.
9).
Position the chain saw in such a way that your body is
clear of the cutting attachment whenever the engine is
running (fig. 10).
Don't put pressure on the saw when reaching the end
of
a cut. The pressure may cause the bar and rota!ing
chain to pop out of the cut or kerf, goout of control and
strike the operator or some other object.
If
the rotating
chain strikes some other object a reactive force (see
pages 10
to
12
)
may cause the chain to strike the
operator.
Reactive forces during
the
cut, including kickback
kickback, pushback and pull-in. Reactive
forces
can
be dangerous1 In any chain saw,
the
powerful
force used
to
cut
wood
can
be
reve
against the operator).
If
the
rotating chain
is
suddenly stopped by contact
with any solid object like
a
log
or
branch or
is
pinched, the reactive forces instantlyoccur.These
reactive forces may result
in
loss
of
control which
may, in turn, cause serious or fatal
injury.
An
understanding of the causes
of
these reactive
forces may help you avoid
loss
of
control.
The most common reactive forces are
-
kickback,
-
pushback,
-
pull-in.
Kickback
Kickback occurs when the upper quadrant
of
the bar
nose contacts a solid object in the wood or is pinched
(fig. 11). The reaction of the cutting force of the chain
causes a rotational force of the chain saw in the direction
opposite tothe chain movement, mainly in the plane
of
the bar. This may fling the bar in an uncontrolled arc
towards the operator.
12
\-Y-w--
This reaction can occur in a fraction of a second and
under some circumstances, cause the guide bar and
chain to strike the operator with enough force to cause
severe or fatal injury.
It
may also occur during limbing.
It also occurs when the nose of the guide bar is pinched
unexpectedly, unintentionally contacts solid material
in the wood (fig.12) or is incorrectly used
to
begin a
plunge or boring cut.
Thegreatertheforceof the kickbackreaction, the more
difficult it becomesforthe operator to control the saw.
9
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