To make the most of their tractors customers are increasingly specifying front linkages and front PTO. Until now, regardless of make, adjustability has been limited and as a result use restricted. Hitching up to implements can also be difficult.
Valtra has responded to this situation by introducing a new generation of front linkage - Valtra's award winning LHLINK – designed specifically for the Valtra N Series
The LHLINK front linkage attaches to the tractor's frame by a vertical pivot. Controlled by a hydraulic ram the linkage can be set to swing horizontally, synchronised with the front wheels or independently.
The lift arms, operated by a pair of hydraulic rams can operate independently or together. This makes hitching of equipment on uneven ground easier and safer while working at angles across the direction of travel is possible.
The Valtra LHLINK front linkage lift capacity is 3.5 tons.
Practical Advantages
A front linkage that swings in a controlled arc in relation to the front wheels has considerable advantages, particularly when used with front and rear mower combinations. For example, when operating with a conventional front linkage around a twisting headland, strips of uncut grass will be left between that cut by the front mower and that cut by the rear mounted unit. By applying Ackerman's steering geometry principle, the front mower moves across in the direction of the turn, therefore avoiding uncut strips of grass. Alternatively the driver may 'push' the front linkage implement over to one side allowing the driver to operate under areas of restricted headroom or along a wavy field edge. In the latter case, when working with front and rear combinations, this avoids the magnification of field margin undulations by the rear mounted machine.
Four control modes are supplied to control the swing of the front linkage.
In mode one the front linkage left/right swing is fully independently of the front wheels.
In the second mode the front linkage swings across in relation to the front wheels. The ratio between the swing of the front linkage and the steering angle of the wheels is infinitely adjustable. The response in the middle of the adjustment range is 50%, so at a 35-degree steering angle results in a front linkage swing of 17.5 degrees. At a response of 1:1 the front linkage movement is directly proportional to the front wheels up to a full 35 degrees, the maximum turning angle of the front linkage in either direction.
In the third mode the front linkage operates as above, but the central position of the front linkage can be varied in either direction.
The fourth mode is designed especially for operating front and rear mower combinations, allowing a higher turning angle for the front linkage than for the wheels. These adjustments eradicate underlap, and poor quality work.
Importantly, since the implement follows the turning radius, reduced lateral loads are put on the implement. This system does not restrict the use of the front PTO in any way as the universal joints are located in the same vertical plane as the pivot centre.
Lift Arms
The position of the lift arms in relation to each other may be adjusted hydraulically, after which their relative position can be locked, the cylinders being connected electronically to a control unit. Space is saved as there is no mechanical torsion bar between the lift arms.
Agritechnica Award
Valtra LHLINK front linkage received the Silver Innovation Award at the Agritechnica Exhibition, Hanover, Germany in 2007.
Valtra will be found in Hall 9 stand E22 at Agritechnica
