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Mini Excavator

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Caterpillar 301.5 Mini Excavator
Mini excavators, also called compact excavators, have been gaining popularity because of their ability to work and maneuver in tight spaces that larger excavators can’t reach. In terms of size, mini excavators are classified as having an operating weight of 9,999 pounds (4,535 kg) and under.[1]

The majority of mini excavators have three assemblies that comprise a house, undercarriage, and work group. The machine movement and function is also controlled through the transfer of hydraulic fluid.

With its versatility and ease to operate and transport, the mini excavator is used by contractors from all different backgrounds and is capable of performing a wide range of tasks that include utility trenching, concrete removal, tree harvesting, repair digs, small scale excavation operations, tree transport and planting, grave digging, light demolition, home repair, renovation, and roadside applications.


[edit] History

[edit] The First Compact Excavators

The mini excavator is a relatively new development in the construction equipment industry. Yanmar designed a mini excavator in 1968, the YNB300, and introduced it to Japanese markets in 1969.

Takeuchi began initial production of its first compact excavator in 1971.[2]

The mini excavator became widely used in the Japanese and European markets first before being introduced to the North American market in the early 1980s. Two events would eventually launch the machine’s popularity in North America.

[edit] Bobcat's Marketing Plan

First and foremost, Bobcat was a dominant manufacturer of the skid steer loader both in North America and around the world. By the 1980s, however, the company began to reposition itself as a manufacturer of compact machinery. This led to a decision to develop and manufacture mini excavators. Bobcat also pledged to stop referring to the small machines as mini excavators branding them as compacts instead.

The next part of the plan was to pitch the compact excavators to the company’s large market for backhoe loaders. A strong case was made when the company emphasized that buyers could buy a skid-steer loader and a compact excavator for the price of a backhoe loader.

The company’s logic to package and sell the two machines caught on. By the 1990s, a number other manufacturers started to follow Bobcat’s lead. About the same time, the rental of compact equipment such as skid steer loaders and compact excavators was taking off. The machines were being snatched up by rental fleets, which purchased them in large quantities, providing equipment users a risk-free opportunity of testing their usefulness.[3]

[edit] Today’s Market

The demand for mini excavators in Japan and Europe still outstrips demand in North America. On the whole, the North American market has been slow to catch on to the use of mini excavators where a preference for backhoe loaders and larger hydraulic excavators has typically predominated. But sales have been steadily increasing and the number of manufacturers offering mini excavators as part of their product line ups has grow substantially. For example, in 1993, only 1,100 units were sold. By 2002, this number had jumped to 11,6000, a 900 percent increase. As of 2003, there were about 27 manufacturers of mini excavators with Bobcat rising far above the rest in the North American market with Kubota coming in a close second. Other manufacturers such Caterpillar, Komatsu, IHI, Deere, Yahmar, Volvo, and Terex accounted for about three to seven percent of the market in 2002.[4] Bobcat is the only manufacturer that produces mini excavators on North American soil. All other manufacturers have the machines produced overseas.

[edit] Features/How it Works

Like their larger counterparts, the mini excavator is comprised of a tracked or wheeled undercarriage or chassis, a cab, and a boom extension with a bucket attachment. Most mini excavators now come with a retractable undercarriage meaning that the tracks can be expanded and detracted to less then three feet (0.91 m) wide or larger to accommodate fitting the machine through tight spaces.[5]

Most mini excavators now utilize hydraulic piston pump technology. This type of technology allows machines to be built with a smaller engine, as piston pumps require 20 percent less horsepower.[6] The latest hydraulic pump systems are a combination of piston and gear pumps in which different pumps carry out different functions. For example, two pumps typically manage the operation of the boom arm and bucket and a third pump manages the swinging of the cab.

Depending on the job a mini excavator will be used for, some important specifications to consider when purchasing are the machine’s weight, dig depth and bucket size and function.

John Deere Mini Excavator

[edit] Machine Weight

The main advantage of the mini excavator is its size—the machines typically weigh between 0 of 9,999 pounds (0 to 4,535 kg).[7] The machine’s weight is what gives it so much versatility. Also because it is light in weight, the mini excavator is suitable for working on different types of sensitive terrain and will ultimately cause less ground damage. The lighter the machine, the more it is adaptable to working on transverse, soft wet ground that heavier machines can’t work on. Also because of their small size, mini excavators are very easy to transport by trailer or a regular truck.

[edit] Dig Depth

Mini excavators are customized to dig at varying depths from as little as four feet (1.2 m) to as much as 12 feet (3.7 m) with the average range of machines on the market achieving dig depths of about 10 feet (3 m).[8] This is a standard depth for handling basic projects and residential construction. Most utility digging is actually less than five feet (1.5 m).[9] Any project that requires a dig depth of over 12 feet (3.7 m) typically requires a larger sized excavator.[10]

[edit] Bucket Sizes

Mini excavators come with a variety of bucket sizes equipped to handle different types of jobs. The bucket size needed will depend on the job being undertaken. A smaller bucket, for example, is more ideal for digging near utility lines as where a bigger bucket is more likely needed for digging in wet and muddy terrain. The standard range of most bucket sizes is from 12 to 24 inches.[11]

[edit] Main Features

Two other notable features of mini excavators is zero tail swing and independent boom swing or an offset boom. Most manufacturers are now building mini excavators with zero tail swing or zero swing radius. Conventional tail swing is the ability of the machine to rotate at 360 degrees. On the contrary, zero tail swing allows the machine to rotate to the full 360 degrees without the cab overlapping the width of the tracks. This is helpful since mini excavators work in such compact spaces. This technology enables the cab to avoid hitting any obstacles when rotating at the base.

Offset booms also known as articulated booms or swing booms are also becoming a standard feature on several models too. The offset boom or independent boom swing enables the machine to dig within close proximity to walls, foundations, or other structures without having to change angles or be realigned. This provides the machine arm with the ability to dig parallel to the tracks.

[edit] Attachments

A number of attachments can be fastened to the boom arm with a quick-coupler attachment mechanism. This has become a standard feature on most mini-excavators and increases the machine’s job tasking capabilities. A number of machines are manufactured with a backfill blades giving the machine dual functional capability to not only dig up dirt but to push dirt back into the hole after being dug up or for basic leveling. Some of the more popular mini excavator attachments in addition to the backfill blade are grapple, auger, hammer and thumb attachments. Bobcat, for example, also produces a range of attachments for its line of mini excavators that include rippers, breakers, clamps, plate compactors, trenchers, and grading and trenching buckets.

[edit] Common Manufacturers

[edit] Additional Photos

See Mini Excavator (Photo Gallery)

[edit] References

  1. RitchieSpecs.02-02-09.
  2. About Us. Takeuchi. 2008-09-28.
  3. How Compacts Became a Big Deal in NA. OBR. 2008-09-28.
  4. Motor Vehicle Transportation. All Business. 2008-09-28.
  5. Mini Excavators. BNET. 2008-09-28.
  6. Mini Excavator. Grading and Excavation. 2008-09-28.
  7. RitchieSpecs.02-02-09.
  8. Mini Excavators. Directory M. 2008-09-28.
  9. Mini Excavators. Grading and Excavation. 2008-09-28.
  10. Mini Excavators. Directory M. 2008-09-28.
  11. Mini Excavators. Directory M. 2008-09-28.