Download  Print this page

How To Avoid Kickback; Maintenance - Husqvarna 120 Operator's Manual

Hide thumbs

Advertisement

Table of Contents
Set the spiked bumper (if one is fitted) just behind the
felling hinge. Use full throttle and advance the chain/bar
slowly into the tree. Make sure the tree does not start to
move in the opposite direction to your intended felling
direction. Drive a wedge or breaking bar into the cut as
soon as it is deep enough.
Finish the felling cut parallel with the directional cut line
so that the distance between them is at least 1/10 of the
trunk diameter. The uncut section of the trunk is called
the felling hinge.
The felling hinge controls the direction that the tree falls
in. (69)
All control over the felling direction is lost if the felling
hinge is too narrow or non-existent, or if the directional
cuts and felling cut are badly placed. (70)
When the felling cut and directional cut are complete the
tree should start to fall by itself or with the aid of a felling
wedge or breaking bar. (71)
We recommend that you use a bar that is longer than the
diameter of the tree, so that you can make the felling cut
and directional cuts with single cutting strokes. See
instructions under the heading Technical data section to
find out which lengths of bar are recommended for your
saw.
There are methods for felling trees with a diameter larger
than the bar length. However these methods involve a
much greater risk that the kickback zone of the bar will
come into contact with the tree. (4)
Freeing a tree that has fallen badly
Freeing a "trapped tree"
It is very dangerous to remove a trapped tree and there is
high accident risk.
Never try to fell the tree that is trapped.
Never work in the risk zone of the hanging trapped tree.
(72)
The safest method is to use a winch.
Tractor-mounted
Portable
Cutting trees and branches that are in tension
Preparations: Work out which side is in tension and
where the point of maximum tension is (i.e. where it would
break if it was bent even more). (73)
Decide which is the safest way to release the tension and
whether you are able to do it safely. In complicated
situations the only safe method is to put aside your chain
saw and use a winch.
General advice:
Position yourself so that you will be clear of the tree or
branch when the tension is released. (74)
Make one or more cuts at or near the point of maximum
tension. Make as many cuts of sufficient depth as
necessary to reduce the tension and make the tree or
branch break at the point of maximum tension. (75)

MAINTENANCE

Never cut straight through a tree or branch that is in
tension!
If you must cut across tree/limb, make two to three cuts,
one inch apart, one to two inches deep. (76)
Continue to cut deeper until tree/limb bends and tension
is released. (77)
Cut tree/limb from outside the bend, after tension has
been released.

How to avoid kickback

!
What is kickback?
The word kickback is used to describe the sudden
reaction that causes the chain saw and bar to jump off an
object when the upper quadrant of the tip of the bar,
known as the kickback zone, touches an object. (50)
Kickback always occurs in the cutting plane of the bar.
Normally the chain saw and bar are thrown backwards
and upwards towards the user. However, the chain 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. (8)
Kickback only occurs if the kickback zone of the bar
touches an object. (4)
Limbing
!
Make sure that you can stand and move about safely.
Work on the left side of the trunk. Work as close as
possible to the chain saw for maximum control. If
possible, let the weight of the chain saw rest on the trunk.
Keep the trunk between you and the chain saw as you
move along the trunk.
Cutting the trunk into logs
See instructions under the heading Basic cutting
technique.
WARNING! Kickback can happen very
suddenly and violently; kicking the
chain saw, bar and chain back at the
user. If this happens when the chain is
moving it can cause very serious, even
fatal injuries. It is vital you understand
what causes kickback and that you can
avoid it by taking care and using the
right working technique.
WARNING! A majority of kickback
accidents occur during limbing. Do not
use the kickback zone of the guide bar.
Be extremely cautious and avoid
contacting the log, other limbs or
objects with the nose of the guide bar.
Be extremely cautious of limbs under
tension. They can spring back toward
you and cause loss of control resulting
in injury.
English
23

Advertisement

Table of Contents
loading

  Also See for Husqvarna 120

This manual is also suitable for:

125