Figure 5-7.—Mechanical advantage and change of direction (winching).Figure 5-8.—Winching by change of directionlifting, and towing) of the trucks to complete therecovery.To upright an overturned truck with a wrecker truck,Overturned TruckFigure 5-8 shows a mechanically disabled 2 1/2-tontruck nosed off a narrow road in such a way that thewrecker cannot be positioned directly behind thevehicle. You may notice that the winch cable is notrunning in a direct straight line with the winch. On anormal winch, this angle causes the wire rope to windoff the side (flange) of the winch drum; however, thewrecker winch has a level winding device that offsetsthe difference. Other vehicles with winches do not havethis device.5-9you should use a sling method of attachent, because apulling force applied to only one point of the frame canresult in a bent frame. A sling lifting attachent is madeup of either two utility chains or two 1-inch fiber ropes.The sling ends are attached to the front and rear liftingdevices on the high side of the overturned truck. Thenthe winch cable is attached to the center of the sling. Aholding force is required to prevent the overturnedvehicle from crashing onto its wheels. The holding force
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