The crawler excavator segment of the off-highway machinery market is seeing key innovations coming to market that will help transform the construction industry. New technology can help deliver earthmoving works more quickly and more accurately, while reducing fuel consumption and emissions, boosting sustainability. And several firms are now offering electric machines, with the benefit of zero emissions.
Komatsu is offering electric excavators for the 13tonne and 21tonne classes that are powered by lithium-ion batteries. The 13tonne class PC138E-11 electric excavator is being offered first in the Japanese market but is being made available for Europe also. The firm is also introducing its PC210LCE-11 electric excavator in Europe. Komatsu says it is keen to develop a market for electric construction machines in the medium-sized range in Europe, which is why these two new models are so important for the company.
The more compact of the two models is aimed particularly at the rental machine market and is powered by a 225kWh lithium-ion battery and features a integrated cooling system. The high capacity battery in the 13tonner is said to offer a long operating time before requiring recharging, while the machine also has a short tailswing design. The combination of electric power and the short tailswing suits the machine for construction sites in urban areas where space may be limited and the benefit of its zero emissions and low working noise will be a major advantage for users.
The machine has a bucket capacity of 0.5m3, with a tail swing radius of just 1.83m. Weighing in a 15.3tonnes the machine has a 72.5kW motor, as well as its 225.6kWh battery.
Komatsu is offering the PC138E-11 excavator with a Smart Construction 3D Machine Guidance kit, which helps to optimise working and allow operators to work to grade accurately and more quickly. This package is said to be simple and versatile package and offers an accessible way for customers to use 2D and 3D machine guidance. The system can be customised with an array of options, allowing the package to be suited a customer’s requirements.
Meanwhile, Develon is now offering its 23tonne DX225LC-7X, a ‘smart’ crawler excavator. This model is said to help operators work more quickly and efficiently and benefits from advanced features such as Full Electric Hydraulic (FEH) technology. The company says that the new model offers advantages for controllability, versatility, operator comfort, uptime and return on investment. It is also said to deliver increased productivity while retaining the robust structure seen on more conventional models.
As well as the FEH system, other standard features of the DX225LC-7X include integrated 2D machine guidance, semi-automatic 2D machine control, a laser receiver, an E-fence virtual wall and a load weighing system.
The firm says that its Full Electric Hydraulic (FEH) technology is similar to the D-ECOPOWER VBO (virtual bleed off) system now incorporated on the standard DX225LC-7 model and all Develon crawler excavators from the DX350LC-7 and above. In effect, the FEH is a VBO system without pilot pressure lines. The joysticks and pedals are fully electric, but give the operator the same feeling as hydraulic joysticks.
For the FEH system, an electric signal is sent to the central controller and is more precise and provides faster information. Back pressure and energy loss are eliminated, by delivering the exact amount of oil needed. As the system does not use pilot pressure, saving fuel. According to Develon, the FEH system allows a reduction in fuel consumption of 8% compared to the D-ECOPOWER VBO system.
When the DX225LC-7X is delivered to the customer, the sensors are already calibrated. The buckets still need to be calibrated but no specific tools are needed for this as the system asks the operator to enter the required measurements, taking around an hour to calibrate three buckets.
The integrated machine guidance system on the DX225LC-7X uses sensors mounted on the front and body to recognise the location of each working device and inform/guide it for the operator. Feedback to the operator is provided through audio and visual displays which allow improved control of the machine in relation to the intended or designed direction of travel. The system will always receive the reference point, even when the machine changes position, without the operator having to reset the reference point every time the machine is moved.
There are three major Machine Control functions, and they can be activated by selecting: Grade Assist; Lift Assist and Weighing; Virtual e-fence.
Grade Assist Mode - On/Off can be set using the instrument panel and joystick. When the Grade Assist mode is set, the boom and bucket are activated in green according to the mode setting in the instrument panel icon.
Bucket Angle Setting - When the Bucket Assist function is activated, the current angle is memorised. When the driver operates the Bucket joystick, the last value is memorized after stopping the operation. When the Bucket Assist mode is on, the Bucket is green on the instrument panel icon.
The Weighing System and Lift Assist function measures and displays the current weight of the bucket as the operator is loading materials and warns the driver when the total loading weight exceeds the target. Power for the machine comes from a six-cylinder DL06V diesel that is Stage V/Tier 4 Final emissions compliant and rated at 129kW.
And Hitachi’s ZX390TC-7 model features a more conventional power system, but is innovative in regard to its high versatility. Hitachi Construction Machinery (Europe) is aiming this machine at use in heavy-duty applications such as demolition jobs.
Although the machine is based on the firm’s conventional ZX350LC-7 excavator, it has been specially adapted to work with larger working tools. The machine features the firm’s proven Zaxis-7 technology and a Stage V-compliant engine but has a larger boom and bucket cylinders. It also has reinforced linkage, allowing it to carry 5tonne tools, such as hydraulic shears for crushing normally used by larger machines.
The ZX390TC-7 is equipped with a full hydraulic control system, suitable for use with all attachments, which can be changed within seconds from the operator’s seat. For added stability when handling heavy attachments, the ZX390TC-7 undercarriage is 250mm longer than system for the standard ZX350LC-7. In addition, the ZX390TC-7 features an additional 1.4tonne counterweight.
To ensure the safety of operators, the machine has side impact protection and a demolition-spec cab with FOPS guard level 2 and high-spec P5A safety glass. Safety is also ensured by the good visibility from the cab, assisted by the 270° view provided by the Aerial Angle camera system.
The structure of the machine is said to be highly rugged, allowing it to cope with heavy-duty applications such as demolition projects. As Hitachi’s quality assurance team approved the modifications, the new model remains covered by the manufacturer’s warranty and service programmes.
