Increasing productivity and timeliness of operations are the the two major drivers behind the ever increasing size of machinery and the latest 15.6m tedder from Kverneland is no exception.

Spreading grass, whether for hay or silage, might appear a simple task and traditionally it was, but as crops have got heavier and tractors more powerful, there has had to come a new approach to the design of the machines to do so.

The Kverneland 85156 C is one answer to the problem and Agriland got the opportunity to see it in action today (Wednesday, June 12).

At nearly 16m wide, there is a huge amount of leverage from the outer tips upon the centre frame, so sturdiness is an absolute pre-requisite, and with sturdiness comes weight.

The best way to handle the weight is to make it a trailed machine which will also ensure it can be all folded up behind the tractor for ease of transport.

Kverneland tedder behind Fendt — At just over 50ft wide, the Kverneland 85156 C covers a lot of ground quickly

TerraFlow follows undulations

Thus then we have the main design features of this latest tedder, but there is still the issue of allowing the the rotor boom to follow the ground contours and the company has developed what it calls its TerraFlow linkage.

This part of the design connects the boom to the axle of the frame by two sort linkages which apply the tractive effort to the boom as well as provide the hinge point for adjusting the rotor angle of attack.

TerraFlow frame linkage — The TerraFlow linkage attaches the rotor boom to the trailer frame

A single ram not only alters the the rotor angle, but also raises them out of work at the headlands and provides the primary action in the folding sequence.

Tedder flexibility

The TerraFlow design amounts to more than just the frame mounting linkage; it encompasses the whole machine, creating a flexible boom allowing each of the 14 rotors to follow ground undulations, according to the company.

Tedder at work — The boom is said to be flexible across its whole width to enable the rotors to follow ground contours

The rotors themselves are small in diameter which is said to provide a much more even distribution of the crop as well as providing a more efficient pick-up.

Fitting many smaller rotors will also help separate the stalks as the crop will encounter a greater number of tines as the tedder moves across the field, neither will the tines be hitting the crop so hard, reducing leaf shatter as it dries.

Kverneland Tedder rotors — The small diameter of the rotors allows for greater contour following and more efficient pick-up

In the field these theoretical advantages do appear to work as the crop is left in a consistent blanket rather than a series of flat ridges with the soil surface still showing through between them, as can happen with other tedders.

Semi swaths from tedder

However, ridging the crop slightly might often have advantages such as reducing dew penetration overnight, or allowing the wind to pass through rather than just over the cut grass.

This is still quite possible to achieve, reducing the rotor speed to the extent that it leaves the grass in defined rows if not a distinct swathe rows, a feature which is more commonly used on the continent rather than in Ireland.

Machine in transport position — When ready for transport, the machine folds neatly onto its trailer frame

As noted, altering the rotor angle and raising them out of work is done by the main ram.

A series of secondary rams activated by sequential valves folds the rotor boom and lowers it in a cradle on the main frame for transport.

Kverneland suggests that the towing tractor be of at least 150hp and forward speeds of up to 12km/h are possible, giving a work rate of 20-25ac per hour.

TerraFlow follows undulations

Tedder flexibility

Semi swaths from tedder

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