7 Kickback and Other Reactive Forces
There are two mechanisms for activating the chain brake if
it is in a properly maintained condition:
– Manual Activation: If a kickback occurs, the chain saw
moves upwards toward the user in a rotating motion
around the front handle. The brake is designed to engage
if the left hand contacts the front hand guard, which is the
activation lever for the brake, and pushes it forward.
– Inertia Activation: All STIHL chain saws are equipped with
an inertia Quickstop chain brake. If the kickback impulse
is strong enough, this alone is sufficient to engage the
brake, even without the operator's hand contacting the
front hand guard.
WARNING
■ To reduce the risk of kickback injury:
– Never use a saw if the chain brake does not function
properly.
– When in doubt, take the saw to an authorized STIHL
servicing dealer for inspection and/or repair.
– Do not use the saw until the problem has been
corrected.
■ In a kickback situation, the front hand guard helps protect
your left hand from contacting the chain. Removal of the
front hand guard on a chain saw equipped with a
0458-791-8621-C
Quickstop chain brake will reduce this protection and also
disable the chain brake, increasing the risk of kickback
injury.
– Never operate your saw without a properly
functioning front hand guard. If the front hand guard
is missing, manual activation and inertia activation of
the chain brake will be completely disabled.
– Never attempt to remove, modify or disable the front
hand guard or any other component of the chain
brake.
■ No Quickstop or other chain brake device prevents
kickback. These devices are designed to reduce the risk
of injury, if activated, in certain kickback situations. To
reduce the risk of severe personal injury or death from
kickback:
– Always follow the instructions in this manual and
follow good working technique. For example,
position your body clear of the cutting attachment
whenever the motor is running. Stand to the left of
the cut while bucking, outside of the cutting plane.
See chapter Holding and Controlling the Chain Saw,
@ 6.5.2.
– Maintain as much distance as possible, and never
less than 25 degrees, between the bar and your
body to ensure that the Quickstop has sufficient time
to activate and stop the chain before reaching any
part of your body.
– Follow the other precautions provided in chapter
@ 8.
■ An improperly maintained chain brake may increase the
time needed to stop the chain after activation, or may not
activate at all. For the Quickstop to reduce the risk of
kickback injury, it must be properly maintained and in
good working order.
– Read and follow the instructions on engaging and
disengaging the chain brake, @ 17.1, and
maintaining and repairing it, @ 17.3.
2. Low Kickback Saw Chain and Reduced Kickback Bars
English
21