Stihl MS 251 Manual De Instrucciones página 17

DANGER
Do not rely on the chain
saw 's insulation against
electric shock. To reduce
the risk of electrocution,
never operate this chain
saw in the vicinity of any
wires or cables (power,
etc.) which may be carry-
ing electric current.To
reduce risk of electrocu-
tion, take extra
precautions when cutting
near power lines. Have
the power switched off
before starting cutting
work in the immediate
vicinity of power lines.
REACTIVE FORCES INCLUDING
KICKBACK
WARNING
Reactive forces may occur any time the
chain is rotating. Reactive forces can
cause serious personal injury.
The powerful force used to cut wood can
be reversed and work against the
operator. If the rotating saw chain is
suddenly and significantly slowed or
MS 251, MS 251 C
stopped by contact with any solid object
such as a log or branch or is pinched, the
reactive forces may occur instantly.
These reactive forces may result in loss
of control, which, in turn, may cause
serious or fatal injury. An understanding
of the causes of these reactive forces
may help you avoid the element of
surprise and loss of control. Surprise
contributes to accidents.
The most common reactive forces are:
kickback,
–
pushback,
–
pull-in.
–
WARNING
Kickback:
Kickback may occur
when the moving saw
chain near the upper
quadrant of the bar nose
contacts a solid object or
is pinched.
When this occurs, the energy driving the
saw chain can create a force that moves
the chain saw in a direction opposite to
the saw chain movement at the point
where the saw chain is slowed or
stopped. This may fling the bar up and
back in a lightning fast reaction mainly in
the plane of the bar and can cause
severe or fatal injury to the operator.
Kickback may occur, for example, when
the saw chain near the upper quadrant
of the bar nose contacts the wood or is
pinched during limbing or when it is
incorrectly used to begin a plunge or
boring cut.
The greater the force of the kickback
reaction, the more difficult it becomes for
the operator to control the chain saw.
Many factors influence the occurrence
and force of the kickback reaction.
These include saw chain speed, the
speed at which the bar and saw chain
contact the object, the angle of contact,
the condition of the saw chain and other
factors.
The type of bar and saw chain you use
is an important factor in the occurrence
and force of the kickback reaction. Some
STIHL bar and saw chain types are
designed to reduce kickback forces.
STIHL recommends the use of reduced
kickback bars and low kickback chains.
English
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