An mini excavator is a large construction machine designed to dig into the ground with a bucket to remove soil or other materials and create trenches, holes, and foundations. For this reason, it is considered one of the main components of major construction projects.
What Is an Mini Excavator?
These machines are designed for digging up soil and similar materials, as well as for lifting, moving and dumping them. This makes them useful for mining and construction applications. They are equipped with an extendable arm operated by a hydraulic system, with a large bucket at the end. The bucket can also be removed or replaced with other attachments to perform different functions.
The operator controls the entire operation of the mini excavator from a cab that can rotate 360° while remaining fixed, ensuring maximum safety.
How does an mini excavator work?
To understand how an mini excavator works, we can break the process down into three main parts:
1. Propulsion
Mini excavators generally run on diesel fuel. Diesel delivers maximum power, ensuring the equipment operates at its most efficient. Using diesel is a much more reliable way to power excavators than using other products, since it can easily handle the demands of the largest job sites.
The diesel engine provides high torque and constant power, allowing for optimal performance even on the roughest terrain. This ensures the machine can perform other tasks too.
2. Track steering
The tracks of a mini excavator are made up of several components that are tensioned once assembled on the machine. Formed from bolted shoes that create a circular track, these tracks wrap around gears that receive power from the engine via the drive shaft. The tracks are responsible for moving the excavator in a straight line forwards and backwards when the gears are engaged.
The operator turns the excavator by stopping one track while moving the other, which causes the entire unit to rotate. An experienced operator can even make the machine spin in a tight space by selecting “reverse” on one track and “forward” on the other.
3. Arm movement
The movement of an excavator's arm is controlled 100% hydraulically. This component forms part of the lower frame chassis. The arm itself has two sections: the boom, which extends from the excavator to the arm, and the arm, which extends from the boom to the bucket. Both sections are connected to each other by hinges.
Both the arm and the bucket are operated by three independent hydraulic cylinders that work together to allow the arm to extend and retract. These cylinders work as follows:
- The first cylinder is located under the boom, and when it extends, the arm rises.
- The second cylinder is attached to the top of the arm and provides greater reach by raising and lowering it.
- The third cylinder controls the movement of the bucket so it can scoop and dig.
Main Components of Compact Excavator
1. House
Attached to the undercarriage with a swing bearing, the house contains your operator’s cab, engine, hydraulic pump and distribution components. The house and the workgroup rotate or “slew” 360 degrees to provide exceptional agility when working in confined areas where larger machines can’t fit.
2. Undercarriage
The undercarriage includes standard rubber excavator tracks surrounding drive sprockets, rollers and idlers which propel the machine. The most common type of undercarriage for smaller mini excavators is the retractable undercarriage. This H-shaped undercarriage can be retracted to temporarily reduce overall machine width, which is valuable for traveling through small openings or working in tight areas. It should be expanded before doing any work. A fixed excavator undercarriage is typically a little wider than the house structure.
3. Workgroup
The boom, arm and any attachment you add to the machine are all included in the workgroup. Compact excavators are unique in that their workgroup is connected to the front of the house with a “swing frame.” The swing frame can be hydraulically pivoted left or right so you can do offset digging parallel to the excavator tracks.
4. Backfill Blade
Hydraulically activated and controlled from inside the excavator cab, the backfill blade is connected to the undercarriage and used for grading, leveling, backfilling and dozing. It can also be used as a stabilizer for the machine depending on its position. An angle blade option is ideal if you need to backfill and grade quickly. This option lets you angle the excavator’s backfill blade 25 degrees left or right to direct soil from one side to the other.
Boom Configuration Options
The boom is the main part of the workgroup that attaches to the house and supports the arm and attachment. There are three common boom setups:
Swing Boom
Most mini excavators use a swing boom, which connects to a swing frame and then to the machine frame with a horizontal pin. This design lets the boom move up and down and also pivot left or right hydraulically, independent of the house.
Knuckle Boom (Articulating Boom)
Mounted directly to the frame, the knuckle boom is a variation of the fixed boom. It’s made up of multiple sections that move up and down, while the outer section can swing left or right hydraulically. The arm itself stays parallel to the machine.
Fixed Boom
A fixed boom is also mounted directly to the frame but can’t pivot side to side—so digging is limited to directly in front of the excavator. This setup is more common on larger, full-size excavators.
Compact Excavator Arms
Bobcat compact excavators come with different arm options designed to match specific applications and job site needs. For instance, an extendable arm gives you the strength and lifting ability of a standard arm, plus extra reach when required.
You can choose from three arm types:
- Standard Arm
- Long Arm
- Extendable Arm
Other Types of Excavators
Aside from the shovel excavator, there are other types of excavators, such as:
Backhoe:
A variation of the excavator. Its bucket moves from top to bottom, working the ground from above. It is used for earthmoving work below ground level or slightly above it.
Clamshell excavator:
Used for vertical movements, such as digging wells, for example.
Advantages of Compact Excavators
Compact excavators offer several benefits compared to full-size machines. Key advantages include:
- Exceptional maneuverability and the ability to access tight spaces.
- Lower ownership and operating costs, thanks to reduced fuel use and maintenance requirements.
- Minimal ground disturbance due to their lighter footprint.
- Reduced environmental impact, with quieter operation and the availability of battery-powered models that produce zero emissions.
- Easy transportation, as most compact excavators can be towed on a trailer behind a pickup or larger vehicle.
- Highly versatile, with a wide range of attachments for various tasks.
Factors to Consider When Choosing the Right Compact Excavator
Picking the right compact excavator is key to getting the most out of your investment. The best machine will match the demands of your tasks while offering maximum value.
Some important factors to consider include:
- Machine size: What is the smallest or largest excavator you need for your type of work?
- Digging depth: Think about how deep you’ll need to dig for ditches, ponds, trenches, or other projects.
- Lifting capacity: Make sure the excavator can handle the weight of materials like construction debris or heavy soil.
- Attachment availability: If your work involves demolition, agriculture, or forestry, consider attachments that boost productivity and precision.
- Job-site and application needs: Identify your most common tasks to choose a machine best suited to your typical projects.
Types of Mini Excavator Machines
There is more than one type of mini excavator, so it is important to know the models and their different capabilities. This way, when we need one, we can make an informed choice for the right machine for our job.
A crawler mini excavator's equipment and entire structure are supported by a system of modular plates similar to those used on military vehicles, such as tanks. The advantage of this crawler movement system is that it can manoeuvre easily in muddy or rough terrain. Why? Because the machine's total weight is distributed across all the track links supporting it. This enables the machine to work on uneven, steep and sloped terrain with ease.
The downside to these models is their reduced speed compared to wheeled machines. They should also not be used on paved surfaces, as this can damage their track system.
Unlike crawler mini excavators, speed is a major advantage. While they are not designed for high-speed movement, their tyre-mounted design undoubtedly provides greater versatility in terms of movement and operation. Using tyres enables the machine to travel through urban areas without damaging the surface it moves on. This makes it ideal for flat or relatively flat terrain, allowing us to take advantage of its extra speed.
However, in terms of stability and traction, it clearly does not match crawler machines. Due to its large size and weight, this model must be anchored to the ground with stabiliser arms each time it is used to prevent unwanted movement caused by weight imbalance.
Safety Tips for Using an Excavator
As we mentioned at the beginning, excavators are powerful machines and can cause damage if not operated correctly. Therefore, if you are going to operate an excavator, it is important to always follow the safety rules outlined below:
- Wear the seatbelt: All excavators with a cab and seat should have a built-in seatbelt.
- Stay seated: Never stand on the excavator while it is in motion. Also, it is necessary to keep your hands and feet inside the cab at all times.
- Stay within project boundaries: Do not operate the excavator near power lines or other unidentified hazards. Before performing any task, clearly mark your work parameters and stick to them. Proper planning ensures you do not dig in areas where underground utilities may be present.
- Do not overload the bucket: Each machine’s bucket is designed with a specific weight limit. Make sure to stay within the suggested weight limit to avoid unnecessary damage to the bucket, boom, or arm. If you think you might exceed it, consider this before purchasing the equipment and choose a larger model if needed.
- Do not work alone: Always have someone nearby to indicate when it is safe to move the excavator. This is absolutely essential when operating any type of heavy machinery, so try to work as a team to complete the job efficiently and safely.