Stihl MSA 200 C-BQ Instruction Manual - Page 14

English stopped by contact with any solid object such as a log or branch or is pinched, the reactive forces may occur instantly. These reactive forces may result in loss of control, which, in turn, may cause serious or fatal injury. An understanding of the causes of these reactive forces may help you avoid the element of surprise and loss of control. Surprise contributes to accidents. The most common reactive forces are: - kickback, - pushback, - pull-in. WARNING Kickback: Kickback may occur when the moving saw chain near the upper quadrant of the bar nose contacts a solid object or is pinched. When this occurs, the energy driving the saw chain can create a force that moves the chain saw in a direction opposite to the saw chain movement at the point where the saw chain is slowed or stopped. This may fling the bar up and back in a lightning fast reaction mainly in the plane of the bar and can cause severe or fatal injury to the operator. Kickback may occur, for example, when the saw chain near the upper quadrant of the bar nose contacts the wood or is pinched during limbing or when it is incorrectly used to begin a plunge or boring cut. The greater the force of the kickback reaction, the more difficult it becomes for the operator to control the chain saw. Many factors influence the occurrence and force of the kickback reaction. These include saw chain speed, the speed at which the bar and saw chain contact the object, the angle of contact, the condition of the saw chain and 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 saw chain types are designed to reduce kickback forces. STIHL recommends the use of reduced kickback bars and low kickback chains. 001BA035 KN Chain Saw Kickback Standard The following standards apply with respect to kickback: - § 19.108 of UL 60745-2-13 - § 5.11 of ANSI/OPEI B175.1-2012 These standards, in the following referred to as "the chain saw kickback standards" 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 saws are measured by applying a computer program to test results from the kickback test machine. WARNING The computer derived angles of the chain saw standards 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 12 MSA 160 C, MSA 200 C