“It’s great to see that we’ve succeeded so well with our scale system for forwarders,” says Per Annemalm, product manager at Komatsu Forest.
For weighing in conjunction with logging and forwarding, crane scales and scales in the bunk are the most interesting alternatives for forwarders. During forwarding, crane tip scales weigh and register weights when unloading. The scale system comprises hardware in the shape of a so-called scale link, which is fitted between the crane tip and the rotator, and the necessary software.
In Sweden, only a small share of timber and forest biomass is weighed using crane scales. In Finland, on the other hand, almost half of all forwarders are fitted with crane scales.
Komatsu’s crane scale has a hydraulic scale link that sends the weight data wirelessly via Bluetooth to the cab. The weight data is then presented as an integral part of the control system. The crane tip scale weighs both when loading and unloading, but the weight is only registered during unloading as this provides the most accurate readings.
The crane scale senses the position of the crane and determines whether the timber is being loaded or unloaded and when the best reading will be achieved. During the loading cycle, when the crane passes over the bunk the system automatically analyzes the measurement values and selects the most representative weight.
The most important and most relevant result of the Skogforsk study on crane-suspended scale systems on forwarders is how well the crane links manage to weigh and calculate the weight of the load. The reason is simple – this is how one normally uses and registers weight when operating a forwarder.
According to the study, the scales measure the weight of the load with good accuracy and a low standard deviation. However, the best performer was Komatsu’s crane scale, which – according to the study – showed very good results in this respect. The standard deviation for Komatsu’s system was 0.13 percent per load, which was the smallest standard deviation among all the crane scales tested. The study concludes that the results indicate that Komatsu has succeeded very well with its algorithms for calculating the weight based on the calibration curves from the scale link.