Ease of transportation combined with excellent lifting capacities – this is the primary development goal that the engineers at Tadano pursued when designing the new AC 5.250-2, which the company showcased in advance at bauma 2022.
As part of the final stretch of development for the crane’s launch, Tadano has now “outfitted” the machine with a number of additional features that represent a significant upgrade to the AC 5.250-2, particularly in the area of safety.
Just to make it clear, however: The engineers at Tadano had already met all their ambitious development goals by the time the AC 5.250-2 was presented in Munich, and the excellent teamwork between the Lauf and Zweibrücken locations played a key role in that.
“This kind of teamwork enabled us to take full advantage of and combine all the know-how and expertise from both our locations,” explains Project Manager Peter Kleinhans.
And the fact that the results are extraordinary can be seen, for example, in the corresponding lifting capacities, which are 10 to 15% higher in many areas and with certain configurations can even go all the way up to 30% higher than previous best values in this class. This enables the AC 5.250-2 to easily lead the pack with a lifting capacity of 14.5 tonnes with a 70-metre boom length at a radius of 12 to 24 metres.
There is also its lifting capacity of 11 tonnes at a radius of 42 metres with a boom length of 47 metres, which is also at the very top – to name just two examples. This impressive run is continued by the new crane’s system length: The 70-metre main boom can be extended by a generous 42 metres with a HAV main boom extension, making it possible to reach a system length of 112 metres. Also notable: All available main boom extensions from 5.8 to 36 metres are self-rigging.
Sophisticated Tadano counterweight concept
The crane can pick up its total counterweight of 80 tonnes in three lifts: 49.6 tonnes with a full 360° radius of up to 6.2 metres followed by two lifts of 15.2 tonnes, with each split into 10 and 5.2 tonnes for mounting on the right and left of the base package. And if necessary, the counterweight can be split into smaller pieces as well, making it possible, for example, to pick up the 5.5-tonne base plate from a distance of up to 20.1 metres across the full radius.
“Thanks to the IC-1 Plus crane control system, which comes as standard, the available radius can even be significantly increased at certain slewing angles,” Peter Kleinhans underscores.
In addition, the fact that the counterweight can be split into a large number of elements with none weighing more than 10 tonnes ensures maximum flexibility for transportation logistics. This means that relatively small trucks can be used for transportation when required by space conditions at a work site.
Taxi crane with 12-tonne axle load
The Tadano team is also tremendously proud of the outstanding transportation configuration options available for the AC 5.250-2. For instance, it can carry a three-sheave hook block for lifting loads of up to 67.3 tonnes or a 5.8-metre heavy-lift runner on board while remaining within a 12-tonne axle load configuration – not to mention that the transportation mounts for the HAV extension are included by default in the 12-tonne axle load.
Moreover, a payload of several hundred kilograms at the rear end is possible. And the whole thing with 16-inch steel rims. The result? The crane can be used as a taxi crane without a support vehicle while remaining within the legal axle load limit of 12 tonnes. And if the axle load is increased to 16.5 tonnes, it can also carry up to 20 tonnes of its maximum counterweight of 80 tonnes. All these advantages contribute to the new Tadano five-axle unit’s enormous versatility.
Latest Tadano tech features on board
Tadano designed the AC 5.250-2 to come with comprehensive equipment as standard right out of the gate, not to mention that all new cranes in the Tadano AC family will benefit from the same equipment effective immediately. The corresponding features include the innovative IC‑1 Plus crane control system, for example. This system determines the crane’s maximum lifting capacity for every boom position as a function of the superstructure’s slewing angle, and in real time to boot. As a result, the crane is always able to take advantage of the maximum lifting capacity available to it – especially during lifts over the outriggers.
In other words, the feature literally provides the greatest support when it comes to lifts in which the outriggers are not fully extended and the counterweight is reduced. All in all, the AC 5.250-2 benefits from this tremendously, as its outriggers can be extended asymmetrically to 0, 25, 50, 75 and 100% positions.
In addition, the one-of-a-kind Surround View camera system, which makes it easier for crane operators to optimally position the crane at work sites, is also optionally available for the Tadano AC 5.250-2: This patented system uses six crane cameras to show a computer-assisted diagram of the maximum possible extension lengths for the outriggers at the crane’s current location.
“With Tadano Surround View, crane operators can take a look at a display in the cab to know exactly how they need to position the crane at their work site in order to extend all outriggers sufficiently and ensure that they are using the required counterweight tailswing radius. This eliminates tedious and time-consuming measurements and testing when looking for a location from which to operate the crane, making the latter ready for use faster,” explains Peter Kleinhans.
The system also provides assistance on the way to the work site by making it easier for crane operators to notice pedestrians and cyclists when turning.
Towards the end of development, Tadano added its TailGUARD active backup assist system as an additional technological innovation in order to maximize safety during travel. This system uses two ultrasonic sensors to monitor the area behind the crane when backing up and works regardless of ambient light conditions.
It shows the distance from stationary and moving objects in the monitoring area on the cab’s monitor, plays an acoustic warning before reaching obstacles, and will stop the crane itself in the event that there is a risk of collision.
The backup assist system is automatically activated the moment the crane’s reverse gear is engaged, making backing up significantly safer – it not only prevents injuries and property damage, but also crane downtimes associated with accidents.
In the future, the AC 5.250-2 will additionally come with one more important safety feature: The Lift Adjuster, which is one of a kind worldwide and is scheduled to become available for the crane in the coming year.
The system consists of a technical control system that can be activated with the press of a button and that measures the boom’s deflection and independently adjusts the lift cylinder in order to compensate for the change in radius caused by the aforementioned deflection and to eliminate the risk of swinging. This way, the Lift Adjuster significantly improves safety in the crane’s work environment.
A comfortable. safe workstation
When developing the AC 5.250-2, the team at Tadano also made sure to attach special importance to the needs of crane operators. Accordingly, all hydraulic components that emit noise are located away from the superstructure cab, where things are comfortably quiet. Moreover, the spacious design behind both cabs ensures maximum operating comfort and a pleasant work environment.
As for safety, intelligently positioned access points, attachment points for operators’ personal safety equipment, and a step that can be extended from the carrier to make it safe and comfortable to enter and exit the superstructure cab all contribute. Moreover, the hill start assist system, which comes as standard, ensures stress-free travel operation when driving up and maneuvering on uphill slopes.
Environmentally friendly operation
Finally, the new AC 5.250-2 also makes a compelling case when it comes to its engine, a state-of-the-art Mercedes-Benz unit with an output of 522 hp and a maximum torque of 2,600 Nm that provides solid propulsion and powerful lifting capacities. And it goes without saying that the HVO-compatible diesel engine meets the latest EU Stage V requirements.
In addition, it is particularly cost-effective thanks to its Eco Mode, which ensures that the engine always outputs the exact amount of power that the crane actually needs at any one time, with the IC-1 crane control system taking care of the corresponding calculations. In addition, the crane also has a fuel-saving start-stop feature on board, with the system turning off the crane engine at the press of a button but without deactivating the control software.
The Tadano AC 5.250-2 tech demo immediately won over a large number of experts and other visitors back when it was revealed at bauma 2022. And this should come as no surprise, as the state-of-the-art five-axle crane raises the bar in a large number of areas, just as promised. This provides the crane with tremendous versatility, which combined with an enormous reach and large lifting capacities makes the unit perfect for erecting tower cranes and for construction projects of all types.