gooseneck then widens into a very massive crossbeam
becoming a pair of side arms extending backward to the
trunnion fastenings on the sides of the scraper bowl.
The gooseneck carries the steering cylinders, the lift
cylinder and lever arm for the apron, and a pair of hoist
cylinders for the bowl. Scraper nomenclature is shown
in figure 10-35.
A scraper has three basic operating parts: the bowl,
the apron, and the ejector.
The bowl (fig. 10-36, view A) is a box with rigid
sides, with the apron as a movable front, and the ejector
as a movable back. The forward edge of the bowl is
fitted with cutting edges. The cutting edges are made of
wear-resistant steel and are bolted to the bottom of the
bowl. The three main cutting edges areas follows:
1. The straight cutting edge is the most efficient
for smooth finish grading.
2. The curved cutting edge penetrates more than
the straight edge.
3. The three-piece cutting edge has the center
piece positioned ahead of the two side pieces for deeper
penetration. The center piece is referred to as the
stinger (fig. 10-37).
The bottom front sides of the bowl usually have
bolted-on wear plates called side cutters. The side
cutters normally receive less wear than the cutting
NOTE: Cutting edges that are worn or damaged
should be replaced to prevent wear of the scraper bowl.
The apron (fig. 10-36, view B) forms the forward
section and a variable amount of the bottom of the bowl
assembly. When closed it rests at the cutting edges.
The apron is hydraulically controlled by a lever in the
When the apron is lifted, it moves
upward and forward far enough to leave the whole front
of the bowl open.
The ejector is the rear wall of the bowl (fig. 10-36,
view C). The most common ejector is hydraulically
controlled and moves forward horizontally, forcing the
load out of the bowl. It is supported by rollers riding on
the floor and on tracks welded to the sides of the bowl.
Figure 10-37.-Scraper cutting edges.