valutazioni - 2, GPA: 4 ( )

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The reaction of the chain drives the saw straight back toward the operator causing loss of saw control. Pushback fre-quently occurs when the top of the bar is used for cutting (fig. 14). 14 15 When felling in the vicinity of roads, railways and power lines, etc., take extra precautions (see fig. 16). Inform the police, utility company or railway authority before beginning to cut. 13 45° 45° = cutting down area 2 1 2 First clear the tree base and work area from inter- fering limbs and brush and clean its lower portion an axe (see fig. 18). When felling, maintain a distance of at least 2 1/2 tree lengths from the nearest person (see fig. 17). Note: The noise of your engine may drown any warning call. Felling instructions: Then, establish a path of escape and remove all obstacles. This path should be opposite to the planned direction of the fall of the tree and at a 45° angle (fig. 19). An alternate path must also be selected. Place all tools and equipment a safe distance away from the tree, but not on the escape path. 17 18 19 Then, determine the placement of the felling notch (fig. 21). The felling notch when properly placed determines the direction in which the tree will fall. It is made perpendicular to the line of fall and should be as close to the ground as possible. Cut the felling notch to a depth of about one-fifth to one-fourth of the trunk diameter (fig. 22). It should be in no case higher than it is deep. Make the felling notch very carefully. 1/10. 1/5. 11/2" (4cm) Felling notch Hinge Felling cut Direction of fall Felling notch Hinge If the tree has large buttress roots, cut into the largest buttresses vertically first (horizontally next) and remove (fig. 20). 20 21 22 23 45° Second cut First cut 14 1 2 3 Begin the felling cut slighty higher than the felling notch and on the opposite side of the tree (fig. 22). Then cut horizontally through towards the felling notch. Apply the chain saw with its spikes directly behind the uncut portion of wood and cut toward the notch (fig. 23). Leave approximately 1/10 of the tree diameter uncut! This is the hinge (fig. 23). Do not cut through the hinge because you could lose control of the direction of the fall. Drive wedges into the felling cut where necessary to control the direction of the fall. Wedges should be of wood, light alloy or plastic - never of steel, which can cause kickback and damage to the chain. Always keep to the side of the falling tree. When the tree starts to fall, shut off the engine, withdraw the bar and walk away on the pre-planned escape path. Watch out for falling limbs. WARNING! Be extremely careful with partially fallen trees which are poorly supported. When the tree hangs or for some other reason does not fall completely, set the saw aside and pull the tree down with a cable winch, block and tackle or tractor. If you try to cut it down with your saw, you may be injured. Sectioning Method WARNING! Felling a tree that has a diameter greater than the length of the guide bar requires use of either the sectioning or plunge-cut method. These methods are extremely dangerous because they involve the use of the nose of the guide bar and can result in kickback. Only properly trained professionals should attempt these techniques. For the sectioning method (fig. 24) make the first cut with the guide bar fanning in toward the hinge. Then, using the bumper spike as a pivot, reposition the saw for the next cut. Avoid repositioning the saw more than necessary. When repositioning for the next cut, keep the guide bar fully engaged in the kerf to keep the felling cut straight. If the saw begins to pinch, insert a wedge to open the cut. On the last cut, do not cut the hinge. 24 Plunge-Cut Method Timber having a diameter more than twice the length of the guide bar reauires the use of the plunge-cut method before making the felling cut. First, cut a large, wide notch. Make a plunge cut in the center of the notch. The plunge cut is made with the guide bar nose. Begin the plunge cut by applying the lower portion of the guide bar nose to the tree at an angle (fig. 25). Cut until depth of the kerf is about the same as the width of the guide bar (fig. 26). Next, align the saw in the direction in which the recess is to be cut. With the saw at full throttle, insert the guide bar in the trunk (fig. 27). Enlarge the plunge cut as shown in illustration (fig. 28) 25 26 27 28 15 1 2 3 WARNING! There is an extreme danger of kickback at this point. Extra caution must be taken to maintain control of the saw. To make the felling cut, follow the sectioning method described previously (fig. 29). If you are inexperienced with a chain saw plunge-cutting should not be attempted. Seek the help of a professional. Limbing Limbing is removing the branches from a fallen tree. WARNING! There is an extreme danger of kickback during the limbing operation. Do not work with the nose of the bar. Be extremely cautious and avoid contacting the log or other limbs with the nose of the guid...

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