The new JOBO RS50 harvester head for the Kranman 621 thinning harvester combines powerful roller feed with increased torque.
Kranman introduces the new JOBO RS50 harvester head to the Kranman 621 harvester. With 50 per cent more torque in the roll feed, feed speeds of up to three meters per second and a completely new tilt function, the RS50 represents a major technological step forward. The biggest change, however, is the basic concept itself – from a stepper with supplementary roll feed to a powerful roll feeder with the ability to step feed when needed.
-
The WeighPro Wireless Weighing Link represents a precise and dependable weighing system designed specifically for round timber, eliminating the need for re-calibration. This system offers operators minimal maintenance requirements, boasting an impressive battery life of up to two years between recharges.
-
That’s a remarkable amount of work hours for a single machine, the Norcar 600 owned by Erkki Rinne is taken well care of, it even has the original Diesel engine.
-
It is not possible to eliminate chain shot, but there are simple steps that can be taken to reduce the risk.
-
Arwel takes great pride in the fact that the mill has no waste whatsoever, “the peelings are used for children’s playgrounds, gardens and for farm animals in barns in the winter and the sawdust has multiple uses in gardens and farms as well.
-
Timber hauliers need to encourage young blood in, and also look after the hauliers we have, we need make the sector a safe and positive place to work.
FIND US ON
From step feeder to roller feeder
For many years, the JOBO ST50 has been a valued harvester head, not least because of its reliability, low oil-flow needs, and ability to handle troublesome strains.
With the new RS50, Finnish head manufacturer JOBO has further developed the design and changed the way the head works.
In the past, step feeding has been the main feeding method, with roll feeding as a complement. In the new RS50, the ratio is the opposite. Here, the focus is on fast, continuous roll feeding, while step feeding remains for situations where extra power and control are needed.
This means most stems in a normal thinning can now be handled with roll feeding, creating a significantly faster and more flexible workflow.
50 per cent higher torque and feed speed up to 3 m/s
One of the biggest changes is the two new roller motors, which provide a whopping 50 per cent more torque compared to its predecessor, the ST50.
At the same time, the feed rollers have been redesigned, with improved profiling, higher positioning and an eight per cent larger diameter.
Together, these changes provide a stronger grip on the trunk and make it possible to roll-feed thicker trees than before.
While the ST50 was in practice adapted for roll feeding of trunks up to about 15-20 centimetres in diameter, the new RS50 can handle trunks up to about 25 centimetres with roll feeding.
Speed has also been significantly improved. The new design enables feed speeds of up to three metres per second.
Flexitilt 30 – a decisive improvement
One of the most important innovations is the new Flexitilt 30 tilt function.
JOBO has increased the head tilt angle to 30 degrees and developed a function that automatically releases the tilt when feeding starts.
This means that the head can follow the natural direction of the strain during feeding instead of being held in a locked position.
This gives the delimbing knives a better opportunity to follow the trunk, which contributes to more even feeding and reduced resistance.
The greater freedom of movement is also particularly valuable when working in hilly terrain, for example when trunks need to be fed up a slope.
The combination of the new tilt function, the more powerful roller motors, and the improved feed rollers makes a big difference.
Higher speed with increased precision
To combine high feed speed with good cutting accuracy, JOBO has equipped the RS50 with proportional control of the roller motors.
The new control lets you vary the feed speed and automatically brake when the trunk approaches the set cutting length.
If necessary, the head can also reverse to find the right position within the preset cutting window, for example, plus or minus three centimetres.
The result is more controlled reprocessing, combining high speed with precise cutting.
Step-feeding remains when needed
Despite the clear focus on roll feeding, JOBO has retained the proven step feeding.
In the case of heavily branched, crooked, or otherwise troublesome trunks, step feed can provide the extra feed power and control the situation requires.
The combination of the two feeding principles gives the head a high degree of flexibility and makes it well adapted to varying stands and working conditions.
For the self-employed forest owner, this means the opportunity to work efficiently in normal thinning without compromising the ability to handle more demanding trees.
Increased reliability and easier service
In addition to improvements to the feeding function, JOBO has implemented several design changes focused on reliability and serviceability.
The valve package has been moved from the tilt to the head itself, which enables better-protected hose routing with fewer moving hoses. This reduces the risk of wear and hose damage during work.
At the same time, the electrical system has been upgraded to 24 volts, which means lower amperage at the same electrical power.
A new local junction box on the unit simplifies troubleshooting and sensor replacement. Integrated LEDs let you quickly check various sensor functions.
The control program has also been further developed with improved adjustment options for hydraulics and sawing functions.
A new step for Kranman 621
The new JOBO RS50 will be an interesting addition to the Kranman 621, a compact harvester developed with the needs of the self-employed forest owner in focus.
Combining the Kranman 621 hydraulic system with RS50’s new feed technology creates the conditions for a more efficient thinning workflow while maintaining the machine’s versatility.
With the RS50, JOBO has taken a significant step in developing harvester heads for smaller forest machines.
Contact forestmachinemagazine@mail.com to get your products and services in front of the world’s largest professional forestry online news network.
#homeoflogging #writtenbyloggersforloggers #loggingallovertheworld
Written by loggers for loggers and dedicated to bringing you the latest forestry news