8 minute read
COMPACT HARVESTER
Swedish manufacturer Kranman AB designs and manufactures harvesting and extraction solutions for smaller scale forestry and in-house harvesting and extraction of thinnings. Initially concentrating on cranes and ATV-based forwarding trailers, the company introduced its Bison compact forwarder in 2011 and moved towards becoming a full line compact forestry equipment producer, developing its first P25 processor in 2016.
Following development of the impressive but ultimately compromised Bison 10000X combination machine for forwarding and harvesting during 2017 and 2018, Kranman shifted its focus to compact harvester TECH SPEC production, and the subsequent 520S harvester and KRANMAN 620S latest generation 620S launched in December 2019 model have been particularly successful for the company. PRO HARVESTER WEIGHT 4,050KG
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As a dedicated harvester for use by self-employed WIDTH 1.67M (ON 400MM TYRES) private forest owners, the 620S has simplicity at its core, making it more affordable and cheaper to run. The sheer popularity of this machine serves to ENGINE KUBOTA FOUR-CYLINDER DIESEL POWER 19KW demonstrate how Kranman has succeeded in filling a very important void in the market, with over 20 units already supplied in its native Sweden and more recently Finland, where the initial units have gone into service following last autumn’s FinnMetko exhibition (read our report on page 67). Speaking to Forestry Machinery about the 620S, Kranman’s sales manager Björn Blixt was upbeat. “We saw a need within the compact harvester market for a HYDRAULICS CONSTANT PRESSURE SYSTEM CRANE KRANMAN PARALLEL MOTION WITH LEVELLING BASE AND INTEGRATED WINCH MAX REACH 5.4M HEAD JOBO ST50 STROKE ACTION TYPE MAX FELLING DIAMETER 300MM
Front bogie home to hydraulic drive wheel; crane base easy to work on.
SIMPLE AND EFFECTIVE
Kranman’s new 620S brings mechanised harvesting within reach of private forest owners wishing to thin their own plantations, writes Eoghan Daly
Jobo ST50 stroke action feed harvesting head.
machine that could be built strong while keeping it simple with no complicated electronics which add to the development and purchase cost and also create potential for problems over the life of the machine. As our customers are private forest owners these values are most important and we are happy to report the 620S has been very well received, which proves there is a strong demand for this type of machine.
FALSE ECONOMY
“The purchase of older forest machines is a route often taken by private forestry owners when they need to equip themselves with their own harvester and forwarder,” Björn continued. “This may bring affordability at the start which can soon be reversed by breakdowns that are very complicated and costly to fix. Our machine can be purchased at less than the cost of a used timber harvester with the added advantage of warranty protection and a much more simple design which can be easily resolved if there is a problem.” Although some may lament the machine’s inability to run a larger roller drive harvesting head, the Jobo ST50 stroke action feed harvesting head is more in-keeping with the machine’s raison d’être, as Björn explained. “A roller drive harvesting head may offer higher production but fitting such a head to our harvester would immediately take away the focus on building a simple machine for private users. If we took the harvester to the roller drive level, we would immediately need a more powerful engine and as a result need to introduce an emissions control system like DPF or SCR.
“The hydraulics would also need to be upscaled and also make the machine bigger to carry the extra weight such a head would need so if we had taken this route, then our machine would be no longer a value for money, simple harvester aimed at the private forestry
market,” he explained. Other important themes that run through the 620S design are high serviceability and easy access to components. These traits ensure that any problems are more easily identified by – and more likely to be resolved by – an operator.
SIZE IS EVERYTHING
The Kranman harvester range comprises four models: the basic 520S with a petrol engine, the base line 620S, 620S Comfort and finally the 620S Pro. Keen to see the ultimate iteration of Kranman’s harvester, we caught up with the very first 620S Pro that was about to begin its service life with the first ever purchaser of a Kranman harvester in Finland.
Even at first glance, it’s very apparent how easy it is to service this machine. Raising the rear hood, a great amount of space surrounds all major components, this achieved thanks to the machine’s long profile. However, the 620S is by no means a cumbersome machine to manoeuvre through the forest. “The 620S is designed to work with a compact forwarder like our Bison models, which guided the dimensions and turning circle of the harvester at design stage,” Björn explained. “This allowed us to have much space available at the rear of the machine to spread the components out which makes everything really accessible and ensures it is a very easy machine to work on should there be a problem.”
The Kubota engine is positioned towards the rear of the compartment, while the cooling radiator takes up the rear most position. Hydraulic elements are located near the front, with the oil cooler ahead of those; the sloping engine hood profile and perforated side panels ensure effective cooling.
The compact 620S certainly appears robust and user-friendly, but its 4,050kg weight when fitted with a Jobo ST50 stroke action harvesting head shows Kranman has successfully balanced the need for strength with light weight.
Measuring 5.4m long and 1.47m wide, the 620S offers 350mm of ground clearance, which is good for its size. The 620S does without stabilisers too, thanks to Kranman’s positioning of the crane base over the front bogie and a generally low centre of gravity. In addition,
Dashboard incorporates rear view camera screen and measurement system display together with control switches and dials.
the 620S employs a centre joint stabilisation lock that is automatically applied by a servo valve system once the accelerator pedal is released. Fluid filled tyres are another stabilising feature.
Like most compact forest machines, the 620S does not employ driven front bogies and relies instead on a hydrostatic drive sprocket between the wheels to provide propulsion. In contrast, the rear wheels are obviously directly hydraulically driven, with the machine’s hydraulic system adequate to satisfy combined demands from travel, crane and head motion. Based on a constant pressure system running at 190bar, the 23cc pump-equipped 620S model offers greater performance over the 520S model’s gear pump arrangement.
Even though Kranman set out to build a simple machine, the company certainly did not forget the importance of a high specification in areas away from the head, as proven by the crane and cabin designs. The in-house developed, parallel action crane provides reassuring strength and reaches to 5.4m without a
Dedicated harvester cabin with great amounts of space and excellent visibility, particularly above the operator’s head.
telescopic extension. In the case of this Pro model, a tilting crane base is offered as standard and ensures the reach remains consistent when working on slopes, while removing strain from crane base elements when slewing in such situations.
BOX CLEVER
The real test of the crane is working at maximum outreach and felling stems at the upper range of possibility with the ST50 harvesting head, which has a maximum felling diameter of 300mm. Like all stroke
A tilting crane action harvesting heads, the reciprocating feed base is fitted as action delivers immense feed force for standard on this delimbing the most stubborn of branches. This range-topping Kranman 620S Pro model. performance compensates for its more sedate feeding speed, with delimbing conducted in a single authoritative action, eliminating the requirement for reverse feeding as is often required with a roller drive head in coarse stands. Another positive of the stroke action head is the fitment of lower knives, which are often absent in smaller roller fed heads and can lead to delimbing compromises where lower branches are present. The head features a length measurement system with 32 preselected lengths feasible through the in-cab control and measurement system.
As the only area of sophistication, the head’s measurement system display is integrated into the cab’s dashboard, with all controls positioned on the seat armrests. The low set operator position and large, sloping windscreen bring whole trees into view, whilst the three-pane window arrangement at the rear further boosts visibility and removes potential blind spots. Air conditioning and a general feeling of spaciousness are icing on the cake.
Of course, this all means nothing without a high rate of productivity, something Björn said the 620S Pro delivers in spades. “The 620S is capable of a work rate of 50 to 60 trees per hour when harvesting 0.05 to 0.08 cubic metre tree sizes.” This performance, topped off with fuel consumption of 3.5 litres per hour, makes the 620S Pro a highly appealing prospect indeed.
Access to an engine doesn’t get much better; the 620S is powered by a four-cylinder Kubota diesel motor with a power rating of 19kW.
KRANMAN BISON 11000 FORWARDER
Kranman offers a comprehensive forwarder range including the largest and most recent introduction, the Bison 11000 model. Weighing 1,850kg, it has a load capacity of 3 tonnes and incorporates the largest crane in the machines size class, offering a maximum reach of 5.6m. Power provision for the machine is by a three-cylinder Kubota engine, while hydraulics are taken care of by two hydrostatic pumps and a single gear pump.
Offering the highest ground clearance in its size class (310mm), the machine benefits from reinforced mainframe construction that doesn’t affect overall weight. Simple by design, the Bison 11000 is an ideal companion for the 620S harvester and would increase the effectiveness of a private forestry thinning team.
