WARNING
The computer derived angles of the
chain saw kickback standard may bear
no relationship to actual kickback bar
rotation angles that may occur in real life
cutting situations.
In addition, features designed to reduce
kickback injuries may lose some of their
effectiveness when they are no longer in
their original condition, especially if they
have been improperly maintained.
Compliance with the chain saw kickback
standard does not automatically mean
that in a real life kickback the bar and
saw chain will rotate at most 45°.
WARNING
In order for chain saws below 3.8 cubic
inches (62 cm³) displacement to comply
with the computed kickback angle
requirements of the chain saw kickback
standard use only the following cutting
attachments:
bar and saw chain combinations
–
listed as complying in the
"Specifications" section of the
instruction manual or
other replacement bar and saw
–
chain combinations marked in
accordance with the standard for
use on the chain saw or
replacement saw chain designated
–
"low kickback saw chain."
See the section on "Low Kickback Saw
Chain and Reduced Kickback Bars."
MS 311, MS 391
Devices for Reducing the Risk of
Kickback Injury
Stihl recommends the use of green
labeled reduced kickback bars and low
kickback saw chains on your chain saw
equipped with a Stihl Quickstop chain
brake.
WARNING
To reduce the risk of injury, never use a
chain saw if the chain brake does not
function properly. Take the chain saw to
your local STIHL servicing dealer. Do
not use the chain saw until the problem
has been rectified.
STIHL Quickstop Chain Brake
STIHL has developed a saw chain
stopping system designed to reduce the
risk of injury in certain kickback
situations. It is called a Quickstop chain
brake.
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 towards the user in a
rotating motion around the front
handle. The brake is designed to
engage if the left hand contacts the
front guard, which is the activation
lever for the brake, and pushes it
forward.
inertia activation: All STIHL chain
–
saws are equipped with an interia
Quickstop chain brake. If the
kickback impulse is strong enough,
this alone is sufficient to engage the
brake even without contacting the
front hand guard.
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