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Front Shovel

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(Redirected from Hydraulic shovel)
Construction Equipment
Mining Equipment
Equipment Specifications - RitchieSpecs
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1998 Komatsu PC650C-5 Pala Frontal
As a member of the hydraulic excavator family, the front shovel’s main purpose is to move earth. It digs above track level in an upward motion crowding material away from itself. It has high breaking force capable of excavating heavily compacted dirt and rocks, but because of its short boom and stick, it must be close to the material it is digging.

The HY-MAC 1080 face shovel developed with the

HY-MAC 1080 excavator was the fore runner of the Face Shovel Model's World wide.

The front shovel consists of crawler tracks, a mount, cab, boom, stick and bucket. It is known for large bucket capacity used to load heavy-duty hauling trucks. The buckets are available in either front or bottom dumping models. In bottom dumping shovels, the shovel separates in the middle so the material can drop through the bottom instead of tilting the bucket forward and dumping out the front.

While originally designed for the single-minded purpose of digging, the front shovel’s versatility has increased throughout the years.

Contents

[edit] History

Largely used in surface mining excavations, the front shovel is a type of hydraulic excavator. It was developed in conjunction with the backhoe hydraulic excavator; as such, their histories are interconnected.

See also: Hydraulic Excavator

[edit] Features/How it Works

The hydraulic front shovel works similarly to the hydraulic excavator except that its bucket digs forward, away from the machine, while the excavator pulls the material toward itself.

See also: Hydraulic Excavator

[edit] Types

One of the largest hydraulic front shovels is O&K’s RH400. It is a 1,000-ton hydraulic giant with a bucket capacity of 57 cubic yards (44 m3). It is powered by dual Cummins K2000E engines totaling 3,350 horsepower.

[edit] TRex & Precision Control

The TRex is a Caterpillar 235 front shovel retrofitted with a precision control system allowing it to be used for nuclear waste cleanup. It showcases the versatility of the front shovel.

TRex stands for Transuranic Storage Area Remote Excavator.[1] It was designed for use at the Radioactive Waste Management Complex (RWMC) located at the Idaho National Engineering Laboratory.

The Caterpillar 235 is considered a reliable excavator capable of withstanding high temperatures and dirty conditions.[2] However, its non-linear, coupled cylinders were not designed for high precision operation. Response can vary depending on temperature and dirt within the cylinders.

RWMC needed a powerful machine capable of heavy lifting of above ground nuclear waste containers and overburden. However, the volatility of the chemicals required the utmost care to be taken in their movement.

While a trained front shovel operator can feel the machine and adjust movement accordingly its accuracy cannot be trusted with precision. So, an advanced technology company, Lockheed Martin Advanced Environmental Systems, was enlisted to develop a system to assist the front shovel to achieve accurate movements.

Lockheed Martin designed a two-pronged approach to allow for precise arm movements. Its adaptive controller was capable of detecting machine response so that adjustments in power could be made automatically. This would allow the operator to control the machine without worry of drifting response from the hydraulic cylinders. In order to achieve this, Lockheed Martin developed a special algorithm that converts an operator’s movements into commanded hydraulic cylinder velocities. The adaptive controller deciphers how much power is needed to complete the operator’s command; this is called feedfoward function.[3] If the feedforward function is correct the arm will move precisely the way the operator intended.

Still, the feedforward function can be affected if dirt gets into the hydraulic fluid. So there is a secondary measure in place to ensure exact movement. This second process is known as negative feedback and it can correct detected errors in movement. A camera monitors where the shovel is, comparing it to where it should be according to the operator’s command. It can then automatically correct that movement by speeding it up or slowing it down accordingly. It also teaches the cylinder to adjust its feedforward function so its next movement will be faster or slower. As the cylinder learns the new feedfoward less negative feedback adjustment is needed.

[edit] Common Manufacturers

[edit] References

  1. Energy Citations. OSTI. Gov. 2008-09-24.
  2. Holland, Owen; McFarland, David. Artificial Ethology. Oxford U of P: 2001. 177.
  3. Holland, Owen; McFarland, David. Artificial Ethology. Oxford U of P: 2001. 177.