Stihl MS 461 R Manual De Instrucciones página 16

English
principles for handheld power
equipment, primarily due to insecure
footing.
WARNING
STIHL does not generally recommend
this practice due to the many variables
the fire / rescue service may encounter
in the field, e.g. steeply sloped roofs,
low-grip conditions such as ice / snow,
the close proximity of bystanders
(including other fire fighters), weakened
structural integrity, etc.
WARNING
Roof venting is extremely dangerous
and should be conducted only
byspecially trained personnel in
accordance with all local, state and
federal rules and regulations. In
addition, in order to reduce the risk of
serious or fatal injury, always observe
the following precautions. Never attempt
to operate any Rescue Saw when you
are not in a secure position, allowing you
to safely hold the saw with both hands.
Never use a Rescue Saw while standing
on an insecure and / or unstable ladder.
Such ladders may fall, slide or collapse.
Never use a Rewscue Saw on a roof
unless you are certain that it is (still)
structurally sound and secure footing is
provided. Avoid cutting through rafters
that will weaken the roof support and
standing on surfaces that will be
weakened by the cut. The frequently
used pre-fab roof trusses held together
by nail-plates are particularly subject to
rapid weakening when exposed to the
heat of a fire. Sometimes, a moveable
platform unattached to the structure,
such as the basket of an aerial truck,
14
may be the only means to provide the
necessary adequate footing and the
freedom to use both hands to operate
the saw.
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 chain is suddenly
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. Sudden
surprise contributes to accidents.
The most common reactive forces are:
kickback,
–
pushback,
–
pull-in.
–
Kickback:
Kickback may occur
when the moving saw
chain near the upper
quadrant of the bar nose
contacts a solid object or
is pinched.
The reaction of the cutting force of the
chain causes a rotational force on the
chain saw in the direction opposite to the
chain movement. This may fling the bar
up and back in a lightning fast reaction in
an uncontrolled arc mainly in the plane
of the bar. Under some cutting
circumstances the bar moves towards
the operator, who may suffer severe or
fatal injury.
Kickback may occur, for example, when
the 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.
MS 461 R