Scrapers are heavy earthmoving machinery used to collect, transport, and dump soil and other materials over short distances. They have a hopper at the rear that is lowered to collect dirt which can then be raised and dumped as needed. Self-propelled scrapers were invented in the 1930s and come in various types like towed, elevating, coal bowl, open bowl, and pull scrapers with capacities ranging from 14 to 44 cubic yards. Scrapers load soil through being pushed by bulldozers and transport it within a mile or two before dumping the collected materials.

1. SCRAPER

2.  Scrapers are a type of heavy machinery used for
earthmoving

An earthmoving machine used for soft soil
 Self-propelled scrapers were invented in the 1930s by R.G.
LeTourneau
 The rear part of the machine is called a hopper
 This hopper is lowered or raised to cut into the ground
collecting the dirt
 The collected earth can be moved and dumped accordingly
as this process is repeated
 Some scrapers work in tandem with a bulldozer
Source: Wikipedia: http://en.wikipedia.org/wiki/Wheel_tractor-scraper
Scraper Description and History

3. Scraper Description
 Standard cubic yard capacities range from 14
yd3
to 44 yd3
 Weight of machinery can be 67,195 lb up to
146,770 lb

4. Scraper Description
 It can be used this is the ideal piece of
earthmoving machinery as it loads, transports
and spreads material. Unfortunately it cannot
be used to transport materials over long
distances because of heating of the tires. It
cannot be used on rocky ground either as this
causes excessive wear.
It takes between 30 seconds or one minute
for the scraper to load itself

5. Standard Usage
 Loading and transporting earth over short
distances (i.e. >2miles)
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7. Operation Cycle
 Operating : for loading, the driver lowers the
body of the scraper onto the soil and opens
the gate. Next a powerful bulldozer pushes
against the back of the machine and pushes
it in order to fill the body. It is the same
principle as the plane used for woodwork

8.  For transport, once the body has been filled,
the driver closes the gate and lifts up the
body. The bulldozer is no longer required, as
it is only used during loading.
 Unloading takes place while the machine is
moving. The driver opens the gate and
activates the ejector which, with the help of a
powerful jack, expels the materials from the
front of the body.

9. Applications
 Dozer: Short haul, less than 100m
 Scraper: Medium haul up to 1,000m

10. Feet
Distance is the principal
factor in selecting haul
units
Hauling Equipment

11. Production Estimation: Scrapers
It is all about cycle time
 Speed
 Type of soil
 Type of scarper
 Total resistance
 Load
 Distance

12. Types of Scrapers
 Towed Scraper
 Elevating Scraper
 Coal Bowl Scraper
 Open Bowl Scraper
 Pull Scraper

13. Towed Scraper

14. Towed Scraper
 A Cat Towed Scraper easily adapts to jobsite conditions. The
scraper can be pulled in single or tandem configurations, or top
loaded with an excavator. On an intermittent basis, the pull scraper
can be push loaded with a bulldozer.
 Ideally pulled by Cat Track-Type Tractors and Challenger™ Special
Application Tractors, hitches and drawbars are available for a wide
variety of tractors.
 Capacity(struck) - 18.8 yd3
to 23.5 yd3
 Capacity(heaped) - 13 yd3
to 17 yd3
 Least expensive
Source: http://www.cat.com/cda/layout?m=111776&x=7

15. Elevating Scraper

16.  Load/haul/spread with little support
equipment.
 Conditions material going into the bowl.
 Work alone capability.
 Elevating scraper aids in compaction.
 Good tool for finish work.
 Loaded Haul: 500 ft - 3,000 ft
 Low rolling resistance.
 Ideal for short cut areas.
 Best suited for favorable material.
 Capable of performing thin, precise lifts

17. Elevating Scrapers
 Capacity (heaped) - 11 yd3
to 23 yd3
 Max. Speed - 24.4 mph to 32 mph
 Ability to homogenize
and condition soil
while loading
Source: http://www.cat.com/cda/layout?m=111776&x=7

18. Coal Bowl Scraper

19.  Handling coal is a big job and relies on
dependable machines. Only Wheel Tractor-
Scrapers designed exclusively for coal
stockpiling and retrieval needs.
 The Caterpillar 637G and 657G Coal Bowl
Scrapers can construct and maintain coal
stockpiles, as well as haul loads to inlet
supply system to meet the burn
requirements of the plant.

20.  Following are some benefits of the Coal Bowl
Scrapers:
 Dual Engines to achieve maximum payloads and
deliver fast cycle times.
 All-Wheel-Drive to work effectively in poor underfoot
conditions and climb piles of slippery, loose coal.
 Large Capacity Coal Scraper Bowls are longer and
higher than standard scraper bowls, which allows to
haul 50 yards (38 meters) with a 637G and an
impressive 73 yards (56 meters) with a 657G.
 Coal bowl scrapers are effective in compacting coal,
which reduces the risk of spontaneous combustion
of coal in the stockpile by eliminating the air spaces.

21. Open Bowl Scraper

22.  Wheel Tractor-Scrapers have a reputation for major
infrastructure work. Jobs like airports and dams and
interstate road building - jobs that require moving
large amounts of dirt with little time. But wheel
tractor-scrapers are hard at work clearing green field
coal mines, removing overburden, digging and
reclaiming mine sites?
 Quick load/unload.
 Spread evenly on the go.
 Broad material appetite.
 Low cost/high production.
 Loaded Haul: 500 ft - 5,000 ft
 Ideal for varying material conditions.
 Ideal for moving high volume of material.

23. Pull Scraper

25. Pull Scraper
 The Noble 417 Pull Scraper is capable of
loading and unloading various types of soil,
including sticky clay materials

26. Scrapers

27. Conventional (Push-loaded, Single
Engine)

35. Safety Procedures and Practices
 Never operate a scraper at speeds that are
unsafe, especially with full pans
 Always wear a safety belt. Uneven terrains
may cause a scraper to tilt
 Be sure that communication between ground
employees is clear and evident
 Proper maintenance and daily checks ensure
safe operating conditions
Source: Integrated Publishing: http://www.tpub.com/content/engine/14081/css/14081_267.htm

36. Safety Procedures and Practices
 Be sure that proper brakes and ropes are all
in working order
 Only trained employees should operate and
work near scrapers
 Do not operate scrapers on unsafe slopes

37. Think Safety
Work Safely