gooseneck then widens into a very massive crossbeambecoming a pair of side arms extending backward to thetrunnion fastenings on the sides of the scraper bowl.The gooseneck carries the steering cylinders, the liftcylinder and lever arm for the apron, and a pair of hoistcylinders for the bowl. Scraper nomenclature is shownin figure 10-35.A scraper has three basic operating parts: the bowl,the apron, and the ejector.BowlThe bowl (fig. 10-36, view A) is a box with rigidsides, with the apron as a movable front, and the ejectoras a movable back. The forward edge of the bowl isfitted with cutting edges. The cutting edges are made ofwear-resistant steel and are bolted to the bottom of thebowl. The three main cutting edges areas follows:1. The straight cutting edge is the most efficientfor smooth finish grading.2. The curved cutting edge penetrates more thanthe straight edge.3. The three-piece cutting edge has the centerpiece positioned ahead of the two side pieces for deeperpenetration. The center piece is referred to as thestinger (fig. 10-37).The bottom front sides of the bowl usually havebolted-on wear plates called side cutters. The sidecutters normally receive less wear than the cuttingedges.NOTE: Cutting edges that are worn or damagedshould be replaced to prevent wear of the scraper bowl.ApronThe apron (fig. 10-36, view B) forms the forwardsection and a variable amount of the bottom of the bowlassembly. When closed it rests at the cutting edges.The apron is hydraulically controlled by a lever in theoperator’s cab.When the apron is lifted, it movesupward and forward far enough to leave the whole frontof the bowl open.EjectorThe ejector is the rear wall of the bowl (fig. 10-36,view C). The most common ejector is hydraulicallycontrolled and moves forward horizontally, forcing theload out of the bowl. It is supported by rollers riding onthe floor and on tracks welded to the sides of the bowl.Figure 10-37.-Scraper cutting edges.10-19
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