|
-14-
that contacting a foreign object in the wood can also
result in loss of chain saw control.
Kickback always occurs in the cutting plane of the saw.
Normally the saw and bar are thrown backwards and
upwards towards the operator. However the saw may
move in a different direction depending on the way it
was being used when the kickback zone of the bar
touched the object.
Take great care when you cut with the top edge of the
bar, i.e. when cutting from the underside of the object.
This is known as cutting on the push stroke. The chain
tries to push the saw back towards the operator. Unless
the operator resists this pushing force there is a risk
that the saw will move so far backwards that only the
kickback zone of the bar is in contact with the tree. This
will cause kickback.
•
Rotational Kickback
can occur when the moving
chain contacts an object at the up- per tip of the guide
bar. This contact can cause the chain to dig into the
object, which stops the chain for an instant. The result
is a lightning fast, reverse reaction which kicks the
guide bar up and back to- ward the operator.
•
Pinch-Kickback
can occur when the wood closes in
and pinches the moving saw chain in the cut along
the top of the guide bar and the saw chain is suddenly
stopped. This sudden stopping of the chain results in
a reversal of the chain force used to cut wood and
causes the saw to move in the opposite direction of
the chain rotation. The saw is driven straight back
toward the operator.
•
Pull-ln
can occur when the moving chain contacts a
foreign object in the wood in the cut along the bottom
of the guide bar and the saw chain is suddenly
stopped. This sudden stopping pulls the saw forward
and away from the operator and could easily cause
the operator to lose control of the chain saw.
•
Avoid Pinch-Kickback:
-
Be extremely aware of situations or obstructions
that can cause material to pinch the top of or
otherwise stop the chain.
-
Do not cut more than one log at a time.
-
Do not twist the saw as the bar is with- drawn from
an undercut when bucking.
•
Avoid Pull-In:
-
Always begin cutting with the engine at full speed
and the saw housing against wood. S Use wedges
made of plastic or wood.
-
Never use metal to hold the cut open.
•
Reduce the chance of kickback
Recognize that kickback can happen. With a basic
understanding of kickback, you can reduce the element
of surprise which contributes to accidents.
-
Most kickback accidents happen during limbing.
Make sure you are standing firmly and that there is
nothing in the way that might make you trip or lose
your balance. Lack of concentration can lead to
kickback if the kickback zone of the bar accidentally
touches a branch, nearby tree or some other object.
-
Cutting with the bottom edge of the bar, i.e. from
the top of the object downwards, is known as
cutting on the pull stroke. In this case the saw pulls
itself towards the tree and the front edge of the saw
provides a natural rest when cutting. Cutting on the
pull stroke gives you better control over the saw
and the position of the kickback zone.
-
Never let the moving chain contact any object at the
tip of the guide bar.
Summary of Contents for NT6260
Page 52: ...WWW CRAFTOP COM ...
