Operator Aware: Comfort and safety issues in the wheeled loaders sector.

Meeting the next stage of engine emissions legislation is the top priority for manufacturers of wheeled loaders. However, improving operator comfort and safety still remains a key focus. Becca Durrant reports.

The next generation of wheeled loaders, equipped with Stage IIIB (Tier 4 Interim) compliant engines will enter the European market in January 2011. The new wave of machines will of course also boast the latest in operator comfort and safety features. However, great strides have already been made in this area as manufacturers are keen to meet the demand for increased machine productivity and reduced operating costs.

Product manager for Hitachi's wheeled loaders, Peter Stuijt said compliance with the engine emissions legislation is currently the over-riding issue in the sector but this is closely followed by improving operator comfort.

He added, "In Western Europe operator comfort has become a decision making factor, often operators get the chance to try several brands (of machine) and state their preference, so it has become very important.

"We feel that Southern Europe is more price driven and labour is not as available in Western Europe as it is elsewhere, so it's definitely important to please the operator in Western Europe with a nice cabin and good access etc."

Echoing Mr Stuijt's sentiments, Arve Opperud, Caterpillar's medium wheeled loader product specialist told CE that, like most construction equipment manufacturers, meeting the next stage of engine emissions regulations is the company's main goal. However, he said improving fuel efficiency and operator comfort and safety are also primary concerns.

"It's especially important in most of Northern Europe and it's spreading further south, people will ask operators what they think about the product and we feel that they have more of a say in the buying process, so it's very important to make sure that the operator is comfortable, safe and has good visibility and so on," he explained.

Operator environment

Despite the level of operator comfort in Hitachi's wheeled loaders having already reached "a very acceptable level" the company is always striving to improve the operator's environment in terms of visibility, noise levels etc, Mr Stuijt told CE.

This is reflected in the company's three new ZW models, the ZW330, ZW370 and ZW550 - due to be officially launched at the Bauma exhibition in April this year.

The new machines are the first to be launched in Europe since the alliance between Hitachi Construction Machinery, Kawasaki Heavy Industries and TCM Corporation was formed in October 2008 and have been designed "with the operator in mind."

Hitachi said the large ZW models deliver enhanced performance and efficiency, as well as increased productivity, "ultimate" comfort and safety and reduced running costs.

Mr Stuijt added, in general, Hitachi's wheeled loader cabins have good visibility as well as plenty of space for the operator and for storage. He added cab floors are easy to clean and the controls are adjustable.

"I think our standard cab offering is fairly complete in terms of things like radios, air conditioning etc - every manufacturer is offering these things but often only as an option," he explained.

Elsewhere, Mr Opperud said Caterpillar has made several changes to its wheeled loaders in order to enhance the operator's working environment, including improving machine access and egress. He added this is especially important for this type of equipment because cabs are high up, so trips and falls can lead to serious injury.

For the European market the company offers a fold-out ladder on its H series machines, which makes it easier for the operator to get in and out of the cab.

Visibility is also crucial he said and requirements now include integrating mirrors, cameras and warning systems on the machines.

"We also hear that customers want us to keep the wheeled loader simple, meaning making easy to understand controls and on-board information systems so operators can drive the loader more efficiently," Mr Opperud told CE.

"We are also constantly working on lowering the sound levels in the cab and tuning sounds because we know that when something doesn't sound right it can add stress for the operator."

Meanwhile, operator comfort was given "high priority" when designing Doosan's new DL420 wheeled loader, the company said. Due to be introduced at Bauma, the new 22,3 tonne model which has a 4 m³ bucket capacity will replace the DL400.

Control

Optimising the productivity of a wheeled loader while also reducing overall operating costs has become easier to achieve with the integration of electronic and automated control systems. Such devices have also helped reduce labour for the operator and have enhanced safety.

Mr Stuijt said these types of systems will have an increasing role to play in the future development of the operator's working environment.

"We feel the impact (of these systems) is becoming more significant because electronic components are becoming more reliable and more affordable so it's likely we will see more and more of them," he told CE.

He added that operator controls as well as machine maintenance systems, like fluid level measuring etc, could all be improved by using electronic systems. "Of course people are looking at reducing overall operating costs but often this goes hand in hand with improving operator comfort because if the operator is happy he will be more productive," he explained.

Another way of enhancing wheeled loader productivity as well as easing labour and improving safety for the operator is to use joysticks for steering.

Case has now introduced joystick steering as an option on its 521E, 621E, 721E, 821E and 921E models and will showcase the system at Bauma. The company said using a joystick leads to a more relaxed and efficient way to operate a wheeled machine, particularly in a repetitive loading operation.

The latest joysticks from the company are mounted on the left hand armrest in the cab, putting the lever in the "perfect position" for the operator, Case added. The transmission directional control switch is mounted in front of the lever and easily reached by the operator, with the transmission kick-down switch on the left of the armrest.

According to the company joystick steering offers full response at speeds up to 19 km/hour, at which point the lever response speed automatically slows to 80%, to keep steering smooth at higher speeds. The operator can also choose from three preset steering response speeds.

Joystick control is activated manually with a warning light showing that it is enabled while the steering wheel remains active and has priority at all times. The transmission shuttle lever next to the steering wheel has priority over the switch in the driver's armrest - this control takes priority over the standard shuttle switch that is next to the loader control lever on the right of the seat.

Operators can choose to kick-down the transmission using the button on the left hand armrest, or the conventional button near the loader control if preferred.

Case said using the finger tip control lever greatly reduces shoulder and elbow fatigue associated with the repetitive circular arm movements demanded by a conventional steering wheel.

"Less fatigue and effort for the driver results in improved safety on site, increased productivity and less wear and tear on the machine," a Case spokesman added.

Fuel usage

As well as equipping wheeled loaders with the latest comfort and safety features manufacturers are looking to use new technologies which help improve fuel efficiency.

Volvo has already started its investigation into hybrid technology but at Bauma this year will introduce a different method of achieving reduced fuel consumption while maintaining productivity, comfort and machine uptime.

The OptiShift driveline technology for the new L150F, L180F and L220F wheeled loaders is a refinement of Volvo's automatic power shift (APS) driveline concept and is designed to increase operator comfort and durability as well as reduce fuel consumption by up to - 15%.

It includes a new torque converter with lock up and free wheel stator and the Volvo patented reverse by braking (RBB) function. Volvo said this combination offers reduced fuel consumption in applications such as load and carry, re-handling, as well as short cycle loading. Other benefits include faster loading cycles, better drive response, increased hill climbing performance, more comfortable deceleration and less loading stress on the torque converter and transmission.

Elsewhere, Hitachi's ZW330, ZW370 and ZW550 models benefit from a number of features that help to reduce fuel consumption and overall running costs. The engine's advanced hydraulic cooling fan adjusts speed in line with changes in operating temperatures, which leads to reduced noise and fuel consumption.

Also helping to reduce fuel consumption is the idle management system which restricts engine speed during long periods of machine inactivity. Meanwhile, the efficient loading system (ELS) increases traction during digging, enabling enhanced productivity while using less fuel.

Doosan's DL420, meanwhile, burns - 7 % less fuel when compared to its predecessor. The new model also features two working modes (standard and economical) in order to optimise the consumption/productivity ratio and adapt to different working conditions.

To further reduce fuel consumption and noise, variable fan speed is controlled by a thermostat.

Outlook

The introduction of Stage IIIB and Stage IV compliant wheeled loaders will be the next big opportunity for manufacturers to showcase the latest operator comfort and safety systems.

Contractors will certainly be spoilt for choice when it comes to choosing new machines next year but in the meantime they will be able to glimpse some new developments at Bauma.

Mr Stuijt told CE, "Contractors are still looking at the lowest cost of ownership or the cost per tonne or per m³. On the other hand we have to comply with many regulations with regard to noise, vibrations and other safety aspects so that whole process is forcing us and other manufacturers to do their homework and improve operator comfort and safety."

Meanwhile, Mr Opperud said until the Stage IV engine emissions regulations have been finalised this issue will remain the main focus for manufacturers, followed by lowering operating costs and machine maintenance as well as increasing fuel efficiency and machine productivity.