Complementing the Kverneland triple mowers as previously reviewed, we also got our hands on one of the firm’s twin rotor rakes for review. James Rickard reports.
The ability to have a wide working width but still comply with transport height limitations has long been a challenge for rake designers, with several manufacturers coming up with clever solutions to get around the problem.
Such solutions include telescoping lift arms, as found on Claas’s range of liner rakes, which once folded for transport allow the rotors to be lowered, and parallel lift arm designs which can be found on the likes of MF/Fendt rakes (formerly Fella), which see the rotors move inwards/downwards as the rotor arms are raised for transport.
But for Kverneland, rather than focussing on what can be done in the lift arm area, it has put the onus of getting the machine lower on the rake’s rear wheels. This means its 9590C Hydro twin rotor rake, which has a working width of up to nine meters, does not have to take its tine arms off and still get under four metres high when folded for transport.
To find out more about this ability and some of the rake’s other innovative features, we tried out the 9590C hydro in first cut silage conditions. And just for good measure, we paired it with a classic Case IH Maxxum MX120. And yes, it did sound awesome.
Similar to most rakes on the market, the 9590C uses a central spine chassis. Up front, a swivelling headstock, mounted to the tractor’s lower link arms, provides 80 degrees of turning angle. This is coupled to the rake’s rear wheels affording rear wheel steering and impressively tight headland turns.
Taking care of rotor lift and offering further ground contour following are lift arms which feature a diamond cut pattern. This allows the arms to twist and flex fore and aft, as the rotors ride over peaks and troughs in the ground.
To reduce service time, the 9590C uses oil immersed, maintenance-free gearbox rotor heads. In addition, a hardened dry-running cam track is also a feature.
Tine arms are also retained in the head via bolts, so should you have a fight with a tree, tine arms can be replaced without having to split the rotor head housing.
Designed with restrictive transport limitations in mind, the 9590C gets around height limits by hydraulically lowing itself by 400mm via rams on the machine’s rear wheels. In combination with the rear wheels, the tractor’s link arms can also be lowered to reduce the rake’s overall transport height to under 4m. Importantly, this can be done without the need to remove any tine arms.
Other benefits of this feature include a lower centre of gravity for transport, which in theory should make for a more stable machine on the road.
Overall, it is a feature which definitely helps when it comes to quickly moving from field to field during busy periods, saving downtime.
If transport height limitations are still an issue, then tine arms can also be removed which are simply held in place by linch pins.
Then, when it comes time to putting the rake back into working position, the whole chassis is raised back up, which also brings with it a huge amount of underbeam clearance.
The 9590C features two 3.85m diameter rotors, with 14 tine arms per rotor. Working width can be hydraulically adjusted from 8m to 9m, and swath width from 1.2m to 2.2m proportional to working width.
Our version of the machine was ‘Hydro’, which features manual adjustment of rotor working height. There is also a ‘Pro’ version of the machine with electric adjustment.
On our machine, rotor height is altered via a crank handle on each rotor at the front of the machine, although confusingly, the stickers which tell you how high the rotors are set at are positioned on the opposite side of the rotor to which you are standing. Also, there is nothing to tell you which way to wind.
However, if you stand behind the rake, with the ability to see both stickers on either side, it does mean you can have a check and quickly compare both rotor heights.
Each tine arm is fitted with four pairs of tines, positioned in a staggered arrangement. This effectively gives a double raking action, said to offer a cleaner sweep. Though hard to judge if this is the case, it certainly did a good job, with the double sweeping action coming into its own early in the morning when grasses are welded to the ground.
Tine arms are also swept backwards for a faster lift of tines, which the firm says particularly helps in sticky, sugary crops. They are also designed to give greater clearance above the swath when the rotors are lifted. However, as we found, rotor clearance could still be greater as they have a tendency to catch the tops of large swaths, particularly when working at the rake’s narrowest width. This said, it did make a very tidy, box-shaped swath.
To follow contours, standard rotor bogies see wheels arranged in a triangular pattern, with twin castor wheels leading (affecting pitch) and two wheels set wide apart (affecting sideways tilt). All wheels are positioned as close as possible to the rotor’s tines for maximum contour following accuracy.
As an option you can specify a bogie with three pairs of castor wheels. As we found though, the standard bogie arrangement did a great job of following some of our more challenging terrain.
To help rotor stability when raising and lowering, a spring system holds the head in place, avoiding and uneven landing of the tines on the ground, reducing soil contamination.
Control of the rake comes from one single acting spool and one double-acting spool, with oil flow diverted via control box to the various functions. The single spool takes care of rotor lift with the ability to lift both rotors at once, or switch between lifting/lowing of each individual rotor.
During operation, we mainly just lifted/lowered both rotors at the same time. However, for more awkward shaped fields it can be useful to lift/lower each rotor on its own, and with a bit of careful timing you can raise one rotor, leave the spool pumping, and switch over to the other rotor which will see it lift. The same can be done when coming back into work if you just leave the spool in float and switch between the two rotors.
But, for absolute convenience, we have heard of users and dealers retrofitting a second oil pipe to one of the rotors and using a spool for each rotor.
As for the double-acting spool, this takes care of working width adjustment and that all important raise and lower of the chassis for transport.
The standout feature of this rake has to be its hydraulically lowering party piece. It is a feature which should help, particularly when it comes to quickly changing from field to field during busy periods, saving downtime. It is certainly an interesting take on a way to reduce transport height.
In-field set-up is fairly simple, although a few more decals to give you a clue as to what the various functions are doing would not go a miss.
Similarly, operation is pretty straightforward, thanks to an intuitive control box to select various functions.
Overall, get the settings right with this rake and you will be rewarded with a clean sweep and a neat swath. However, as we found, the rake could do with a bit more lift clearance as the rotors can catch some of the taller swaths.