The brand new Kesla 19RH-III and 21RH-III harvester heads introduce the latest Kesla technology.
The new models represent the latest technology on the market in terms of structure, materials and functionality. Thanks to their modular structure, the new 19RH-III and 21RH-III models can easily be optimized to work under highly varying conditions, with different types of timber and on different base machines. Their strategy as a leading independent harvester head manufacturer steers them to develop the products to work optimally with the hydraulics and control systems of different base machines. This is ideal for builders of excavator harvesters and those harvester manufacturers who don’t have own heads in their product lines.
The frame modules of the new models are machined in one piece after the welding assembly. The moving parts of the heads, such as feeding roller arms and delimbing knives, are made of cast steel. This helps attain good structure dimensional accuracy, which will further prolong the structural life of harvester heads, already known to be durable, and improve their operating features.
The shafts and bearings of roller arms, delimbing knives and tilt joints are as sturdy as those in the competitors’ heads in larger size categories, to ensure the mechanical strength of the new heads. In terms of their frame structure and hydraulics, the new models are largely based on the same solutions as the sturdy 27RH – 30RH-II models in Kesla’s range, which have been proven to be reliable and durable working on machines around the world. Besides efficiency, the new harvester head models have good reliability and low energy consumption. Regarding reliability, a key factor is the new structure which helps protect the harvester head’s cylinders and their hoses without compromising easy maintenance. In energy consumption, significant factors include powerful hydraulics and Kesla’s unique progressive roller geometry, which ensures maximal traction and minimized friction during the processing.
The goals related to the power-to-weight ratio of the harvester heads introduced to the market have been set higher than ever, so the zero-series of heads has undergone a very long period of testing by means of debarking in plantations in tropical areas and thinning in Finland, using several types of base machines. The testing also involved some of the most important forestry companies managing plantations on the market, doing very detailed follow-up.
The Kesla 19RH-III is a 3-knife harvester head equipped with one rear delimbing knife, whose weight starts from 680 kg (1,500 lb). The short three-knife model is very capable of handling crooked trees, and its slightly lower weight makes it suitable for base machines where the harvester head selection is weight-critical. The weight of the 4-knife 21RH-III model, equipped with two rear delimbing knives, starts from 720 kg (1,587 lb). The four-knife model works best for handling slightly sturdier timber. The total weight is, naturally, affected by the assembly. The maximum opening of feeding rollers in both models is 42 cm (16.5 in), and the maximum sawing diameter is 54 cm (21.3 cm).
The harvester heads are suitable for first and later thinning, as well as harvesting of short-rotation eucalypt and Acacia plantations, with or without debarking. The 19RH-III and 21RH-III were launched in April 2020. Deliveries of the new models to clients will begin during the summer of 2020. Source