Reactive Forces - Stihl MSA 220 C Manual De Instrucciones

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► Do not work near live electric cables.
4.7.2 Limbing
WARNING
■ If the underside of the felled tree is limbed
first, it will no longer be supported on the
ground by branches. The tree can move dur‐
ing cutting work. This can result in serious or
fatal injuries.
► Cut through large limbs on the underside of
the tree only after it has been bucked.
► Do not stand on the log while limbing it.
■ A branch may fall to the ground during limbing.
The user may trip, fall or be seriously injured.
► Limb from the base to the crown of the tree.
4.7.3 Felling
WARNING
■ Inexperienced users cannot assess the dan‐
gers when felling a tree. Persons may be seri‐
ously or fatally injured and property may be
damaged.
► The user needs relevant knowledge of fell‐
ing technology and experience of felling
work.
► If anything is unclear, consult an experi‐
enced expert for assistance and to deter‐
mine the appropriate felling technique.
■ A tree and branches can fall on bystanders or
objects during felling. The larger the falling
parts are, the greater the risk of serious or
fatal injury to people. Damage to property may
occur.
► Determine direction of fall so that the area
in which the tree falls is clear.
► Do not allow bystanders, children or ani‐
mals within 2.5 tree lengths of the work
area.
► Remove broken or dead branches from the
tree crown before felling.
► If bent or withered branches cannot be
removed from the tree crown, consult an
experienced expert for assistance and to
determine the appropriate felling technique.
► Be aware of the tree crown and crowns of
neighboring trees, and keep clear of falling
branches.
■ When the tree falls the trunk could break or
spring back in the direction of the user. This
may result in serious or fatal injury to the user.
► Plan a sideways escape path behind the
tree.
► Walk backwards along the escape path and
observe the falling tree.
40
► Do not walk backwards down slopes.
■ Obstacles in the work area and on the escape
path can hinder the user. The user may trip
and fall. This may result in serious or fatal
injury to the user.
► Remove all obstacles from the work area
and escape path.
■ If you cut into or through the hinge, stabilizing
strap or holding strap too soon, the intended
direction of fall cannot be controlled or the tree
may fall prematurely. Persons may be seri‐
ously or fatally injured and property may be
damaged.
► Do not cut into or through the hinge.
► Cut through the stabilizing strap or holding
strap last.
► If the tree begins to fall too soon: Abandon
the felling cut and retreat along the escape
path.
■ Kickback can occur if the rotating chain in the
upper quadrant of the bar nose makes contact
with a hard felling wedge and is suddenly
braked. There is a risk of serious or fatal
injury.
► Use aluminum or plastic felling wedges.
■ If the tree does not fall all the way to the
ground or gets caught on another tree, the
operator cannot finish the operation in a con‐
trolled manner.
► Stop the felling operation and use a cable
winch or suitable vehicle to pull the tree to
the ground.
4.8

Reactive Forces

4.8.1 Kickback
Kickback can be caused for the following rea‐
sons:
– The rotating saw chain in the upper quadrant
of the bar nose makes contact with a hard
object and is suddenly braked.
– The rotating saw chain is pinched at the bar
nose.
The chain brake cannot prevent kickback.
4 Safety Precautions
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