valutazioni - 2, GPA: 4.5
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It is not designed for prying or shoveling away limbs, roots or other objects. When sawing, make sure that the saw chain does not touch any foreign materials such as rocks, nails and the like (fig. 8). Such objects may be flung off, damage the saw chain or cause the saw to kickback. 9 9 10 This reaction can occur in a fraction of a second and under some circumstances, cause the guide bar and chain to strike the operator with enough force to cause severe or fatal injury. It may also occur during limbing. It also occurs when the nose of the guide bar is pinched unexpectedly, unintentionally contacts solid material in the wood (fig.12) or 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 saw. Kickback: Kickback occurs when the upper quadrant of the bar nose contacts a solid object in the wood or is pinched (fig. 11). The reaction of the cutting force of the chain causes a rotational force of the chain saw in the direction opposite to the chain movement, mainly in the plane of the bar. This may fling the bar in an uncontrolled arc towards the operator. 11 12 clear of the cutting attachment whenever the engine is running (fig. 10). Don’t put pressure on the saw when reaching the end of a cut. The pressure may cause the bar and rotating chain to pop out of the cut or kerf, go out of control and strike the operator or some other object. If the rotating chain strikes some other object a reactive force (see pages 10 to 12 ) may cause the chain to strike the operator. Reactive forces during the cut, including kickback WARNING! Reactive forces, that may occur during any cut are kickback, pushback and pull-in. Reactive forces can be dangerous! In any chain saw, the powerful force used to cut wood can be reversed (and work against the operator). If the rotating chain is suddenly stopped by contact with any solid object like a log or branch or is pinched, the reactive forces instantly occur. These reactive forces may result in loss of control which may, in turn, cause serious or fatal injury. An understanding of the causes of these reactive forces may help you avoid loss of control. The most common reactive forces are - kickback, - pushback, - pull-in. In order to keep control of your saw, always maintain a firm foothold. Never work on a ladder, in a tree or on any other insecure support. Never use the saw above shoulder height (fig. 9). Position the chain saw in such a way that your body is Many factors influence the occurence and force of the kickback reaction. The type of bar and saw chain you use is a factor in the force of the kickback reaction. Many factors influence the occurence and force of the kickback reaction. The type of bar and saw chain you use is a factor in the force of the kickback reaction. Kickback force increase with the rate of impact. The contact angle between the nose of the bar and the foreign object (fig. 11). Kickback is most pronounced in the upper quadrant of the bar nose. MAKITA chain types are designed to reduce kickback forces. The depth gauges: Improper lowering of the depth gauges also increases the risk of a kickback. Saw chain cutter sharpness: WARNING! A dull improperly sharpened chain may increase the risk of kickback. Always cut with a properly sharpened chain. Devices for reducing the risk of kickback injury MAKITA have developed a special chain brake to reduce the risk of kickbacks. This chain brake increases the safety factor on the job, e.g. when the saw suddenly kicks upwards the chain stops rotating within a fraction of a second. A deflection guard on the disengaging lever of the chain brake and a loop rear handle ensure that the operator’s hands are fully protected at all times. Kickback tendency increases as the radius or size of the guide bar nose increases. MAKITA have developed guide bars with small nose radius, to reduce the kickback tendency. WARNING! No chain brake prevents kickback. These brakes are designed only to stop the chain, if activated. To ensure a proper operation of the chain brake, it must be properly maintained. Furthermore, there must be a sufficient distance between the operator and the bar to ensure that the chain brake has sufficient time to activate and stop the chain before potential contact with the operator. 13 To avoid kickback The best protection from personal-injury that may result from kickback is to avoid kickback situations: 1. Hold the chain saw firmly with both hands and maintain a secure grip. 2. Be aware of the location of the guide bar nose at all times. 3. Never bring the nose of the guide bar in contact with any object. Do not cut limbs with the nose of the guide bar. Be especially careful with small, tough limbs, small size brush and saplings which may easily catch the chain. 4. Don’t overreach. 5. Don’t cut above shoulder height. 6. Begin cutting and continue at full throttle. 7. Cut only one log at a time. 8. Use extreme...