Stihl MSA 120 C Instruction Manual page 21

7 Kickback and Other Reactive Forces
the location and angle of contact, the condition of the saw
chain, and how quickly the chain is slowed or stopped,
among 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 chain types
are designed to reduce kickback forces.
– STIHL recommends the use of reduced kickback
bars and low kickback chains.
7.2.2 Chain Saw Kickback Standards
The following standards apply with respect to kickback:
– § 19.108 of UL 60745-2-13
– § 5.11 of ANSI/OPEI B175.1
– for Canada: CSA Z62.3
These standards, referred to as "the chain saw kickback
standards" in this chapter, set certain performance and
design criteria related to chain saw kickback.
To comply with the chain saw kickback standards, electric
chain saws:
– must, in their original condition, meet a 45° computer-
derived kickback angle when equipped with certain cutting
attachments; and
– must be equipped with at least two devices to reduce the
risk of kickback injury, such as a chain brake, low kickback
chain, reduced kickback bar, etc.
The computer-derived angles for electric chain saws are
measured by applying a computer program to test results
from a kickback test machine.
WARNING
￭ Compliance with the chain saw kickback standards does
not mean that the bar and saw chain will rotate at most 45°
in a real life kickback. The computer-derived angles of the
chain saw standards may bear no relationship to actual
kickback bar rotation angles that may occur in a real life
cutting situation. Devices designed to reduce the risk of
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kickback injuries may lose some of their effectiveness
when they are no longer in their original condition,
especially if they have been improperly maintained.
– Read and follow the safety precautions and
instructions in this manual.
– When working, always position the chain saw such
that your body is clear of the cutting attachment and
outside of the cutting plane.
– Follow the maintenance and service instructions in
this manual.
￭ For the chain saw to meet the chain saw kickback
standards, use only the following cutting attachments:
– Compliant bar and chain combinations listed in
"Combinations of Guide Bars and Saw Chains,"
@ 27;
– Other replacement bar and saw chain combinations
marked in accordance with the standards for use on
the chain saw; or
– Replacement saw chain designated "low kickback
saw chain."
7.2.3 Devices for Reducing the Risk of Kickback Injury
The STIHL Quickstop chain brake and STIHL's green-
labeled, reduced kickback bars and green-labeled, low
kickback saw chains are designed to reduce the risk of
kickback injury.
1. STIHL Quickstop Chain Brake
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