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(Redirected from Cable excavator)

Cable Excavator

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(Redirected from Cable excavator)
Construction Equipment
Mining Equipment
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Cable excavators are large earthmoving machines used for heavy excavation of materials with the use of cables or wire ropes. Almost obsolete, cable excavators were once used in mining and some construction applications and usually consisted of a variety of attachments that could transform it into a backhoe, skimmer, dragline, and more. Aside from a few companies that still manufacture them, cable excavators have been replaced by hydraulic excavators due to their cheaper costs, easier operation and faster mobility.

Contents

[edit] History

[edit] Early Designs

The cable excavator derives from William S. Otis’ steam shovel, which was made in 1835. The first ever shovel to be documented, it was rail-mounted and consisted of a one-cubic yard (0.76 m3) dipper and a boom. It was capable of swinging only half-circle. It did not take off immediately, as most projects continued to be excavated by hand. Otis also had patents on the shovel that most companies could not access until well after his death.

The first fully-revolving machine was built by Whitaker & Sons (England) in 1884, but it was not hugely popular.

[edit] Evolution and Competition

Gradually, companies began to develop an interest in this hard-working machine. Companies such as Bucyrus began developing and manufacturing shovels for use in mining quarries. Bucyrus produced the 120-B, the first machine to produce full revolutions.

Until the 1920s, when manufacturing companies were beginning to emerge, shovels were powered by steam and mounted on rails, making their use and mobility very restrictive. Shovels experienced a sharp change, as did most earthmoving machinery, and companies began producing machines that were powered by gas and oil. No longer were these machines just mounted on rails. Companies began mounting them on crawlers and wheels as well.

With the onset of the hydraulic excavator, cable excavators met somewhat of a decline, especially when it came to small- to medium-sized excavators. They continued their existence, however, and were popular for large, heavy-duty excavation projects.

By the 1930s, the Great Depression had knocked out many excavator companies. Those that remained carried on with steadfast determination. While hydraulic excavators dominated the excavator group, cable excavators were given a rebirth in the mining industry. Bucyrus International, formerly Bucryus-Erie, detected this and produced machines to meet the demands of the industry. The model 120-B was its first mine and quarry shovel. Built in 1925, it had a five cubic yard (3.8 m3) capacity. Three hundred of these were produced before they were discontinued 26 years later.[1]

Cable excavators were also made multi-functional with the use of attachments. Implements made the boom longer, making it a fair rival to its cousin, the stripping shovel. The cable excavator could not produce the same results as the stripping shovel but it was somewhat successful in smaller applications. These types, sometimes referred to as highlifts, reached the height of their popularity in the 1950s.

In a period when most companies were producing machines bigger than the next, very few manufacturers dared to venture larger with the cable excavator. Those that did were in it for the long haul. Manufacturers such as Menck & Hambrock, Ruston & Hornsby, Clark/Lima, P&H, Bucyrus, Marion, and American Hoist  & Derrick Co. attempted what others did not dare—producing machines with a capacity larger than six cubic yards (4.6 m3).

[edit] The Decline of the Cable Excavator

By the 1980s, the cable excavator began a steady decline that would lead to a near extinction. The work it could accomplish was simply executed more effectively by other machines—hydraulic excavators, wheel loaders, etc. Cable excavators' extinction is due in large part to the cheaper, faster, and easier to operate hydraulic excavators. Today, only the largest of the cable excavators still exist, and only two manufacturers still provide them: P&H and Bucyrus. Both companies have models ranging over the 20 cubic yard (15.2 m3) capacity. Cable excavators can also be found in the form of draglines from companies such as Little Giant and Link-Belt.

[edit] Famous Machines

Famous machines included Bucyrus’s 88-B, the largest construction sized shovel with four cubic yards (3.04 m3) capacity, in 1946; the smallest was also produced by Bucyrus: the 10-B, a .375 cubic yard (0.29 m3) capacity weighing just 10 tons. The American Hoist & Derrick Co. produced the American 750—its first steam-powered machine, replaced by the American Railroad Ditcher of 1905. American cable excavators were modernized with the use of crawlers when its Gopher Series was introduced in 1928.[2]

[edit] Features/How it Works

The cable excavator carries attachments that can transform it into a skimmer, hoe, a shovel or a dragline for a variety of applications. It can be used to excavate the earth, in surface mining, digging foundations and digging tunnels for sewers and pipes.

The cable excavator consists of hoists for its cables/wire ropes, a crowd arm, a bucket, and shovels.[3]

Much like other types of excavators, the cable excavator uses its arm to lower the bucket and extract dirt or rock from the earth. What makes it distinct is that it does so with a series of cables or wire ropes that are pulled and hoisted in the direction it is moved. Early cable excavators could only revolve minimally and move by rail tracks. Later versions could be mounted on crawlers or wheels for easier mobility and accessibility, making it suitable for a variety of operations.

Functions such as the cable winding drum, rotation and propelling are controlled by the use of clutches, gears and chains via the engine.

[edit] Common Manufacturers

[edit] References

  1. Haddock, Keith. Colossal Earthmovers. MBI Publishing Company: 2000.
  2. Haddock, Keith. The Earthmover Encyclopedia. St. Pauls: Motorbooks, 2002.
  3. Cable Excavators. Construction Machinery. 2008-09-09.