Types of Excavators and Attachments
Compact excavators are designed to perform the same functions as standard excavators, but in confined spaces or areas with obstacles. Typical compact excavators have a lower machine weight than standard excavators. This allows the excavators to be moved between jobsites more easily, and also provides a reduction in fuel costs. To more efficiently maneuver and operate in confined spaces, compact excavator manufacturers have implemented a number of features including tail swing configuration and smaller undercarriage width.
Tail swing configuration
The tail swing configuration of compact excavators is crucial when working around obstacles such as vehicles, walls, etc. If the excavator tail comes into contact with these obstacles during a swing, both the obstacles and the machine can be damaged. Compact excavator manufactures have implemented several innovative technologies to handle this, including reduced tail swing and zero tail swing configurations.
- Reduced tail swing configurations provide a tight swing with only a few inches of overhang. This allows operators to get close to obstacles without the possibility of hitting them during a swing.
- Zero tail configuration is the tightest swing available. This means that there is no overhang, which allows operators to get the machine extremely close to obstacles without coming in contact.
Compact excavators typically have smaller widths than standard excavators, and some even incorporate an expandable undercarriage feature that allows the undercarriage width to be decreased when traveling between tight spaces (doorways, gates, etc.), then it is expanded once the machine has passed the obstacles or confined area.
Crawler excavators are the most common type of excavator found on construction sites. The main difference between crawler excavators and other types of excavators is the chassis. Instead of wheels, crawler excavators have a track similar to a tank, which increases stability, balance and efficiency. Crawler excavators have the ability to perform a variety of construction functions including:
- Trench digging
- Hole digging
- Foundation digging
- Material handling
- Earth moving
It should be noted that some of the above functions can only be performed with an appropriate attachment for the excavator. Crawler excavators are slower than wheeled excavators, but are more balanced and stable during work operations. They are also less apt to get stuck in muddy conditions, and more stable for working on steep or other rough terrain.
Dragline Excavators utilize a unique process in order to efficiently perform construction operations. The excavators utilize a hoist rope which attaches to the bucket using a hoist coupler. On the other side of the bucket, a drag line is attached to the bucket using a drag coupler. The hoist rope is used to lower or raise the bucket to the desired height or depth, then the drag rope is used to drag the bucket toward the operator. Dragline excavators can be wheeled or crawler-type excavators, and can be used for a variety of construction operations including:
- Excavation of roads
- Deep pile driving
- Port/harbor construction
- Surface mining
- Deep excavation
- Under-water operations
Dragline excavators are some of the largest excavators available. Smaller draglines weigh around 8,000 tons, while the largest draglines top out around 13,000 tons. They are typically found on strip-mining sites and tar-sand mining sites.
Long reach excavators
A long reach excavator is a type of excavator that has an extended arm for more efficient operations in hard-to-reach locations. The extended arms for long reach excavators can range from around 40 feet to over 100 feet. Original long reach excavators were called "waterway" machines because the long-arm design was very effective at working on waterways. The extended arms are perfect for dredging large amounts of material from underwater locations.
Long reach excavators should not be confused with high reach excavators. High reach excavators have an extended boom arm that allows operators to reach especially high buildings. This is typically used for demolition purposes, and the extended boom arm essentially grabs the top of a building marked for demolition and "pulls" the building down in a managed setting. This provides a more stable and controlled demolition than the use of wrecking balls.
Suction Excavators utilize a powerful suction attached to large pipes directed into the ground in order to remove material from underground locations. Suction pipe is typically around one foot in diameter and suction air speed can reach 220 mph (100 meters per second) of suction force. Suction excavators weigh between 7-32 tons and the horsepower ranges between 172-400 HP.
Suction controls allow operators to switch the suction on and off. For instance, if the pipe encounters an object that is too large to enter the pipe, the suction can be temporarily deactivated in order to release the large object. Suction excavating is the most common type of excavating for underground utility operations, as it reduces chances of damaging underground utilities by more than 50 percent.
For an excavator to be compatible with auger attachments, they must be implemented with two-way, auxiliary hydraulic circuits. All modern excavators have this technology. Typical mounting brackets for augers include the single pin hitch, double pin hitch and the double pin cradle hitch. The range of attachments allows the quick change of attachments, as well as the ability to interchange attachments from other brands.
Augers are available for different types of terrain. A range of torque specifications and length accommodate the appropriate digging conditions. Higher torque provides maximum digging power, while length can range anywhere from 100 mm on smaller machines to 1200 mm on larger machines. Digging depth can reach up to 10 Meters.
Standard augers are capable of most digging tasks. However, for tough digging conditions (such as rock and sandstone), augers implemented with Tungsten teeth may be required.
Breakers are similar to jackhammers, but are much larger. These attachments are used specifically for tough jobs such as breaking stone or concrete. Breakers can be quickly and easily attached, and can be utilized on various machines. Modern breakers typically range from 60 to 1000 ft.-lb. impact energy.
Buckets are typically made of hard steel, and have teeth on the digging edge of the bucket to ensure maximum digging and scooping performance. There are several types of buckets designed for various tasks.
- Ditching bucket: Designed for grading stones, typically on large-scale projects. Width: 5-6 feet.
- Trenching bucket: Designed for digging trenches quickly and effectively. Width: 6-24 inches.
If the bucket can be thought of as a hand, the clamp attachment would be the thumb. This allows operators to pick up large material (concrete, tree stumps, etc.) that would not typically fit in the bucket. Clamps can be used with trenching buckets or three-tine grapple. Easy attachment configuration allows the clamp to be attached and detached quickly to avoid disruptions in operations.
Flail Mowers are used for landscaping operations such as chopping tall grass or tough shrubs where a standard mower simply wouldn't make the cut. The mower can be angled to use as a shrub or hedge trimmer, and can perform a variety of other useful landscaping functions. Flails are designed to bounce off of immovable objects, although some are designed to pick up and eject smaller objects such as rocks.
Grading blades are designed for smoothing out rough areas of terrain that has already been demolished. Attachments come in a variety of sizes specifically designed for use with various machines and terrain.
Grapples are used for picking up large pieces or amounts of material. Some are designed for tough construction jobs, while others are designed for waste handling operations. Quick coupling attachments allow grapples to quickly be interchanged with other machines and attachments. Grapples can be hydraulically rotated and angled in order to approach material from practically any angle.