The French company Kuhn which manufactures agricultural and land management machines is a global conglomerate. Kuhn has previously produced various types of tractor-mounted mowers and hedge trimmers intended to serve as part of the machinery on a farm, but recently new opportunities from new potential customers emerged.
A new conceivable customer group was envisaged, such as road maintenance contractors and public authorities. High requirements were set for industrial design and selection of materials.
Road maintenance constractors and public authorities are, if possible, even more demanding as customers than the agricultural segment.
The arm for the hedge and grass cutter developed by Kuhn must be capable of withstanding the twisting and bending forces that occur.
“We were determined to achieve an optimised product,” says Pascal Gautron, the Project Engineer at Kuhn.
The arm which is rotatable through all three axes, while the mower unit must be capable of being angled separately to cover the largest possible area, at the right distance from the ground or trees. In addition, the tractor often runs on uneven sloping ground, and the rear of the tractor is fitted with a heavy counterweight designed to balance the weight of the long arm.
“But there is a vast difference between a machine that may be used for perhaps a hundred or two hundred hours annually and a machine that has the strength and durability necessary to be in operation for 1500 hours a year,” says Mickaël Peterschmitt.
By using advanced high strength steel – Domex 700MC and Weldox 700 – Kuhn has developed a new hedge and grass cutter – named Pro-Longer – with better performance. The arm of the new cutter is lighter and stronger.
“Our first thought was to increase the strength of the arm, but we soon realised that it was equally important to reduce the total weight,” says Pascal Gautron.
The working area as well as the operator ergonomics is improved. A semi leading parallelogram design enables the unit to be operated sufficiently far forward, so that the operator will be able to see more easily how the mowing work is progressing. By switching steel, the main arm of the Pro-Longer is no less than 23 percent lighter, which made it possible to substantially reduce the weight of the counterweight which balances the arm. Thereby fuel consumption is reduced. In spite of the lower weight, the whole arm is now 20 percent stronger.