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Pull Scraper

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(Redirected from Pull-type scraper)
Agricultural Equipment
2006 Ashland I180TS Agricultural Hydraulic Ejector Pull Scraper
Pull scrapers are machines used to level out or strip off topsoil; they are typically used for smaller job sites and in agricultural applications. These units are able to move in soft, wet soils, as well as sand. Unlike the motor scraper, pull scrapers are not motorized and must therefore be pulled by another vehicle. The models of today generally have a capacity of 7- to 18-cubic yards (5.5 to 13.8 m3) but can have a capacity up to 31 cubic yards (24 m3). Though pull scrapers are known as the predecessors to motor scrapers and might therefore seem outdated, they have become more popular over the past few years.[1]

Contents

[edit] History

The pull scraper in its earliest form was pulled by horses or mules. This scoop-like contraption was controlled by an operator holding its handles while walking directly behind it.

[edit] Incorporating the Wheel

The operation of these scrapers changed in the 1870s with the addition of wheels. One of the first pull scrapers to appear with this new addition was developed by C.H. Smith & Co.[2] , a railroad company from Iowa. Initially, the company had developed this steel-wheeled horse-drawn scraper solely for its own purposes. The design, however, gained popularity and the company began to get requests from others to build machines for resale. As a result, a new company was started in 1879: the Western Wheeled Scraper Co.

Around the same time came the introduction of a horse-drawn wheeled pull scraper by Californian blacksmith Abijah McCall. With his partner F. Dusy, he developed a pull scraper with two wheels located at the front; this machine was known as the Fresno, after its birthplace.

[edit] The Advent of Tractor-pulled Scrapers

Shortly after the dawn of steel-wheeled scrapers came another advancement: the use of steam tractors, rather than horses or mules, to pull the machines. Thanks to the power of the steam tractors, the scrapers could now include bigger bowls with a greater capacity. These large bowls were dragged along the ground; for that reason, these machines were known as drag scrapers. Another popular tractor-pulled scraper was known as the rotary scraper. It was comprised of a cylindrical bowl that, once having collected a load, would rotate 360 degrees into the carrying position.

[edit] Carry Type Scrapers

The carry scraper was another type designed during the early years of pull scraper development. This model was made in large numbers by the Baker Manufacturing Co., and was branded the Baker-Maney scraper. This scraper, containing a bowl suspended in a frame, could be used alone, or in a train of up to six units. One operator would often have the task of mounting each scraper in a train, one by one, in order to load them. A similar design was the Euclid wheel scraper, introduced by the Euclid Crane & Hoist Co.

[edit] The Gondola

In the mid-1920s, Robert Gilmore LeTourneau built the Gondola, a wheel-mounted pull scraper with a capacity of six cubic yards (4.6 m3). This machine was constructed with brazed metal instead of the standard rivets. LeTourneau began using electric welding, a brand-new practice, after the development of this machine. In addition, the Gondola was equipped with electric motors using rack-and-pinion drive.

2004 Icon Series 18 Hydraulic Pull Scraper

[edit] The Mountain Mover

Following the introduction of the Gondola, LeTourneau developed a pull scraper known as the Mountain Mover. This scraper, the first to include two or more bowls[3], was designed as a power saver. The principle in conventional single-bowl scrapers is that the last few yards of material take much more time and power to load than the first. By developing a scraper with multiple bowls, each could be loaded in turn, saving power. The Mountain Mover had two bowls; one telescoped inside the other. In total, the scraper, powered with electric motors, had a 12-cubic yard (9.2-m3) capacity and wide steel wheels.

[edit] The Cable Control Unit

In 1928, LeTourneau developed the first cable control unit.[4] This unit controlled a scraper’s motions by way of a double-drum winch mounted on the tractor.

[edit] The Highboy

After a short period during which LeTourneau attempted, rather unsuccessfully, to develop a self-propelled scraper, he returned to the design of pull scrapers. Of note is 1929’s development of the Highboy, one of the first pull scrapers to be operated by a cable control unit. This model included a high frame above its bowl, from which a spring-loaded tailgate was suspended. This tailgate was then pulled through an arc to sweep the load out of the bowl.

[edit] The Carryall

1932 brought the development of LeTourneau’s next scraper, the Carryall. The nine cubic yard Model A was the first scraper to be mounted on pneumatic tires. Its successor, the Model B was the first to include the features that are considered standard today[5] : a bowl that could be raised off the ground, an apron to drop down over a load of material to retain it, and, to push the load out through the front, a separate ejector.

[edit] Bucyrus-Erie Enters the Market

The first offering from the Bucyrus-Erie Co. was in 1936. This scraper was a four-wheel contraption pulled by a cable from a tractor comprised of a single drum winch. This machine, whose single cable did the work of the bowl and apron, as well as dumping loads, was complicated and therefore high maintenance – it never achieved great popularity.

Bucyrus-Erie’s following design, resulted in the production of the S-series scrapers, which were produced for 12 years. These five- to 12-cubic yard (3.8- to 9.2-m3) scrapers employed a two-drum winch. The scraper, contrary to traditional design, had a moveable floor, which lifted the bowl from the back, and dumped the load forward. By 1948, Bucyrus-Erie had come out with its larger, more conventional rear-dumping B-series scrapers.

[edit] Caterpillar Joins the Competition

In the midst of the success and advancement of pull scrapers, Caterpillar decided to offer its own line. Beginning in 1946, the company introduced the No. 70 and No. 80. They designed these models specifically to be coupled with Caterpillar’s D7 and D8 tractors. The No. 40 was one of the first pull scrapers to be operated by hydraulics rather than cables.[6] By 1955, Caterpillar’s first series of scrapers were being replaced by a line known as the 400-series. The only remaining model that continued to be used was the No. 60; it was discontinued in 1972.

[edit] Pull Scrapers Today

Pull scrapers, having been used in agricultural applications for over 100 years, have not become obsolete. Over the past several years, they have experience a five to 10 percent growth in annual sales. Their continued popularity is due, in part, to the fact that they are much more cost-effective than motor scrapers, costing one-third the price, as well as having greater fuel efficiency.[7] In addition, the detachability element of a pull scraper and its corresponding tractor provide the operator with versatility.

There has been a recent trend toward pull scrapers that are heavier and more durable, as they can now be pulled by larger, faster tractors.[8] This will enable the scrapers to do larger, more heavy-duty jobs more efficiently.

[edit] Features/How it Works

The pull scraper, mounted on tires, is pulled hydraulically by an agricultural or crawler tractor. Normally pulled in a train, many small pull scrapers are combined and can have a large load capacity. In contrast to a standard motor scraper, the pull models are loaded without the assistance of another machine, such as a crawler tractor. Using a blade, pull scrapers cut into the ground making shallow, high-speed cuts through topsoil before loading the material into one or more bowls.

[edit] Common Manufacturers

[edit] Additional Photos

Bron 63F Pull Scraper
Kokudo 23SP Pull Pan
Cepco S180 Pull Scraper
1950 Caterpillar 70 Pull Type Cable Scraper
1964 Caterpillar 463 Pull Scraper
1999 John Deere 1812C Pull Scraper
2000 Icon 24-ton Side Dump trailer
2003 Noble 417 Pull Ejector Scraper
2006 K-Tec 3100 31 yd. Pull Scraper
Bee Gee LDS16 16 ft. Pull Scraper
Porter Welding LDS14 Pull Scraper
Steiger Toreq Hydraulic Pull Scraper
Reynolds 14C Pull Scraper

[edit] References

  1. Ritchie Bros. Auctioneers. Equipment Valuation Assistant. Ritchie Bros. Auctioneers Incorporated: 2004.
  2. Haddock, Keith. Giant Earthmovers: An Illustrated History. MBI Publishing Company: 1998.
  3. Haddock, Keith. Giant Earthmovers: An Illustrated History. MBI Publishing Company: 1998.
  4. Haddock, Keith. Giant Earthmovers: An Illustrated History. MBI Publishing Company: 1998.
  5. Haddock, Keith. Giant Earthmovers: An Illustrated History. MBI Publishing Company: 1998.
  6. Haddock, Keith. Giant Earthmovers: An Illustrated History. MBI Publishing Company: 1998.
  7. Flexibility. Grading and Excavation. 2008-09-23.
  8. Flexibility. Grading and Excavation. 2008-09-23.