Instruction Manual

GS 461
English
13
muffler. To reduce the risk of fire or burn
injury, do not continue work with a
damaged or improperly mounted
cylinder housing or a
damaged/deformed muffler shell.
Your muffler is furnished with a spark
arresting screen designed to reduce the
risk of fire from the emission of hot
particles. Never operate your unit with a
missing or damaged spark arresting
screen. If your gas/oil mix ratio is correct
(i.e., not too rich), this screen will
normally stay clean as a result of the
heat from the muffler and need no
service or maintenance. If you
experience loss of performance and you
suspect a clogged screen, have your
muffler serviced by a STIHL servicing
dealer. Some state or federal laws or
regulations may require a properly
maintained spark arrestor for certain
uses. See the "Maintenance, Repair and
Storing" section of these Safety
Precautions.
Reactive Forces
WARNING
Reactive forces may occur any time the
chain is rotating. Reactive forces can
cause serious personal injury. The
powerful force used to cut through a
workpiece can be reversed and work
against the operator. If the rotating chain
is suddenly stopped by contact with any
solid object or by a pinch or binding,
reactive forces can occur instantly and
may result in the operator losing control
of the concrete cutter, which, in turn,
may result in serious or fatal injury.
An understanding of the causes of these
reactive forces may help you avoid loss
of control. Reactive forces are exerted in
a direction opposite to the direction in
which the chain is moving at the point of
contact or of pinching / binding. If the
chain is slowed solely by frictional
contact with a solid object, such as the
workpiece, the resulting reactive forces
are normally moderate and readily
controllable by an operator who is
holding the machine properly. If,
however, the chain is abruptly slowed or
stopped by a pinch or severe bind, the
reactive forces may be substantially
greater. The greater the force
generated, the more difficult it will be for
the operator to control the concrete
cutter. Loss of control can result in
severe personal injury.
The most common reactive forces are:
– rotational reactive forces,
– pull-in,
– pushback.
A = Rotational reactive forces
WARNING
Rotational reactive forces may occur
when the moving chain near the upper
quadrant of the bar nose is pinched. This
may fling the bar up and back in the
plane of he bar. In some circumstances,
the bar may move towards the operator,
who may suffer severe or fatal injury.
These reactive forces may occur, for
example, when plunge-cutting. See
section on plunge-cutting.
B = Pull-in
Pull-in may occur when the chain on the
bottom of the bar is suddenly stopped
when it is pinched, caught or encounters
a foreign object in the workpiece. The
reaction of the chain pulls the concrete
cutter forward and may cause the
operator to lose control.
Pull-in occurs when the chain is not
rotating at full speed before it contacts
the workpiece.
To avoid Pull-in
1. Always start a cut with the chain
rotating at full speed
2. The risk of pull-in may also be
reduced by using wedges to keep
the kerf or cut open.
2411BA051 KN
A
2411BA052 KN
B