SCRAPER

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

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

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

Standard Usage

Loading and transporting earth over short distances (i.e. >2miles)

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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

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.

Applications

Dozer: Short haul, less than 100m Scraper: Medium haul up to 1,000m

Feet

Distance is the principal factor in selecting haul units

Hauling Equipment

Production Estimation: Scrapers It is all about cycle time Speed

Type of soil Type of scarper Total resistance Load

Distance

Types of Scrapers

Towed Scraper Elevating Scraper Coal Bowl Scraper Open Bowl Scraper Pull Scraper

Towed Scraper

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

Elevating Scraper

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

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

Coal Bowl Scraper

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.

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.

Open Bowl Scraper

 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.

Pull Scraper

Pull Scraper The Noble 417 Pull Scraper is capable of

loading and unloading various types of soil, including sticky clay materials

Scrapers

Conventional (Push-loaded, Single Engine)

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

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

Think Safety

Work Safely