Development Story 01
The new model in the TK Series features a durable structure and high lifting capability that are ideal for handling the tough jobs of any general construction site. The model features the conventional performance of the series and adds merits of “improved transportability” and “conformity with 2014 emission gas regulations”.
On June 2017, sales commenced for TK750G/TK750GFS (hereafter TK750G), a new model of the extremely well-received TK Series, which performs outstandingly in spite of the tough conditions of a general construction site. With all the conventional features such as a robust structure, outstanding operability and high lifting capability, this landmark model satisfies the new industry expectations for "under 3m transportation width".
The conventional TK Series was highly evaluated. However, conformity with 2014 emission gas regulations became an urgent issue. Takayoshi Aoishi, who was in charge of the marketing strategy, recalled the following.
In terms of time and cost effectiveness, we felt that the model development of the new TK750 with the well-rooted evaluation would be best served by simply replacing the engine with one that conformed with the 2014 emission gas regulations at the beginning.
However, every time a crawler crane is transported by trailer, A “special vehicle permit” is required of the unit. The preparation of documents, the complicated application procedure, the lead time required before the permit is approved, the waiting time until the transport trailer is deployed and the limits of transportation time; all these factors acted to suppress the actual operation time of the crane.
When we consider the merits to the customer, it is better to simplify the process of arranging a trailer and submitting an application, not to mention reducing the time required for obtaining permission. For that purpose, we thought it would be best if we could reduce the minimum transportation width without crawlers to less than 3m.
But for Masaaki Higuchi, who was in charge of sales and actually dealt with customers directly, worried about it at the time.
Because of the popularity of the conventional machines, we worried that changing the vehicle width could adversely affect the model’s performance.
To overcome this difficulties, the development team attended meetings with customers in various locations to hear their thoughts on the matter. These meetings served to deepen their conviction that "changing the vehicle width was absolutely necessary". Project manager Takahiro Hanamoto remembered the following.
Within the company, there were those who objected to any major changes. However, the more we heard from our customers, the more we wanted to apply our technical prowess towards reducing the vehicle width while maintaining the model’s performance.
So, Aoishi drew up 8 simulation scenarios that assumed various conditions.
We demonstrated that spending time and money in an attempt to reduce the vehicle width would be beneficial to sales and profitability in the long run, and also influence the market share positively. As a result, we were able to obtain approval from management.
In April 2014, backed by Hanamoto’s slogan, "Imagine 10 years later and see what nobody's seen before", the project officially began.
The theme of the project was to maintain the strength of the slimmed down unit while effectively attaching various elements including an engine. Yoshio Sasaoka, who was in charge of the overall design, addressed this task.
There were several difficult issues including where to put the exhaust pipe in a very limited space. But we could develop a machine that was tough and successfully performed as the conventional machines on the front line of general construction.
For the engine, we adopted Daimler AG's "OM936LA (MTU6R1000)". The engine carries a "Urea Selective Catalytic Reduction" as exhaust gas postprocessing device for reducing PM (particulate matter) and NOx (nitrogen compound) emissions. What's more, the engine cleared the standard value for construction machine noise reduction.
On the other hand, Akira Okada, who was in charge of the system development, had a problem in maintaining a fixed temperature around the engine.
The machine was designed for hard use and it was pretty much expected that the temperature around the engine would rise at the construction site. For fan control to secure stable heat balance, we repeated the process of calculation and test result verification until we arrived at the most suitable solution.
With the TK750G, we maintained the performance of the conventional machines which was extremely well-received by our customers.
While we changed various aspects of the design, we held down the shortest boom length to 10m and devised the placement of the winch to maintain a compact rear swing radius. We also followed the customer’s demand and provided performances equivalent to those of our conventional machines such as a high lifting capability for areas with height limitations and workability in narrow spaces.
Also, Takeya Miyamura, who was in charge of the trials, emphasizes that the viewpoint of customers were foremost in his mind even during the testing stage.
Not to mention the examination assumed a severe worksite, we decided the set point of the lever's interval,position and response by taking the “sense“ of operators into consideration.
The model was finished with the default value at an average that anybody would find reasonable and the detailed settings were left to be fine-tuned at the time of the vehicle’s delivery. The knowhow accumulated in this development project is sure to contribute in the development of future TK Series models.
The TK750G is already enjoying a succession of inquiries from many customers. The members of the development team commented, “We would like to have the model applied in the severe construction site right along with our conventional machines and the machines of other companies.”
* The contents described above is based on the information at the time of issuing (October, 2017).