Equipment spotlight: excavators

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Hitachi hydraulic excavator

Excavators, or diggers as they are sometimes called, are most commonly used for digging rocks and soil. But with the wide variety of attachments available, excavators can also be used for cutting, crushing, drilling, and much more.

Compared to many other types of machinery, excavators are not all that recent of a development. In fact, the first documented excavator was one developed by William S. Otis nearly 200 years ago in 1835.

Primitive by today's standards, Otis' steam powered shovel was essentially a one-cubic yard digger, rail mounted to a cable operated boom, which was capable of swinging only half-circle.

An End to Steam

It would take until 1884 until the first fully-revolving excavator was built by Whitaker & Sons and another 36 years until 1920 before gas and oil powered machines began to replace steam.

With the combustion engine came greater mobility and, for the first time, in the 1920s companies began mounting excavators to wheels and crawlers in place of stationary diggers.

CAT hydraulic excavator

Cables Snap in Favor of Hydraulics

Hydraulics was first introduced to shovels around 1882 and by the 1950s it began an eventual domination of the industry that was nearly completed by the 1970s. Hydraulic operated machines have an advantage in being both cheaper and easier to operate, especially when it comes to small and mid-size machines.

Cable-operated machines live on however, particularly for heavy-duty excavation projects and in mining applications where they enjoy advantages over less powerful hydraulic machines.

It wouldn't be until the 1980s that cable excavators became nearly extinct. Their work was replaced by hydraulic machines and improved by wheel loaders. Only the largest cable excavators exist today, with capacities ranging over 20 cubic-yards.

Caterpillar 6090 hydraulic excavator

Front Shovels and Massive Modern Diggers

Today, modern excavators and front shovels - diggers with buckets that face upward to move material away from them - can be massive.

Models such as Hitachi's 570-ton EX5500 and Caterpillar's 360-ton 5230B are among the largest in the industry today.

Even so, they are dwarfed by Liebherr's R996 and Komatsu's PC8000, each weighing 720-tons and 755-tons respectively and having a capacity over 44-cubic yards.

The largest machine of all is the Caterpillar 6090 (formerly called the Terex/O&K RH-400 before being purchased by Caterpillar). It weighs in at 1,000-tons and can excavate 57-cubic yards, a far leap from the digger's 1-cubic yard humble beginnings.

Search our current inventory to find hydraulic excavators, mini excavators from 1-4.9 tons and more for sale in upcoming auctions.

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