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Scraper Operations
Hauling

Equipment Operator Basic - Beginning construction equipment operators manual
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Figure 10-39.-Entering the cut. Figure 10-40.—Loading the bowl. Figure 10-41.-Loaded bowl. The  scraper  work  cycle  has  four  phases  of operation: loading, hauling, spreading or unloading, and returning to the cut. Loading When  loading,  enter  the  cut  with  the  ejector positioned at the rear of the bowl, open the apron enough to allow material to enter the bowl (normally 4 to 8 inches above the leading edge of the bowl), and then lower the bowl to cut a depth of 1 to 1 1/2 inches. The gear that the transmission is engaged in depends on the nature  of  the  material  being  cut.  For  light,  loose material, a relatively high gear can be used. For heavy compacted material, a low gear is used; however, to obtain a full load, you should use a lower gear, even in loose material. As the scraper proceeds through the cut, the material is loosened by the scraper cutting edges and forced  into  the  bowl  by  the  forward  motion  of  the scraper  (fig.  10-39). NOTE: Avoid spinning the scraper tires during cut operations. Spinning the tires is nonproductive and causes  expensive  premature  wear  of  the  tires, differential,  and  transmission. The material entering the bowl boils back against the ejector and forward against the apron (fig. 10-40). When the bowl is filled to capacity (commonly know as heaped), close the apron, and at the same time, raise the bowl 1 or 2 inches above the ground (fig. 10-41). On scrapers equipped with diverter valves in the apron hoist system, the bowl automatically starts raising, while the apron control lever is held in the lower position. After the scraper is fully loaded and the bowl is raised, continue to travel out of the cut with the scraper bowl at a height that spreads out the material that piles in front of the cutting edges. The push cat supplies extra power to the scraper during loading operations. When a push cat is used, it should be positioned about 45 degrees off the lane to be cut. The scraper should start loading before the push cat makes a smooth contact with the rear push block (fig. 10-42). Figure  10-42.-Push  block. 10-21







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