English
location and angle of contact, the condition of the chain,
and how quickly the chain is slowed or stopped, among
other factors.
– The type of bar and 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:
– § 19.107 of UL 62841-4-1
– § 5.11 of ANSI/OPEI B175.1
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 25° 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 chain will rotate at most 25° 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.
20
7 Kickback and Other Reactive Forces
■ Devices designed to reduce the risk of 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,
@ 28;
– Other replacement bar and chain combinations
marked in accordance with the standards for use on
the chain saw.
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 chains are designed to reduce the risk of kickback
injury.
1. STIHL Quickstop Chain Brake
0458-791-8621-C