engleski

Comparison between some technical characteristics of Steyr farming tractors equipped with 3 variants of Tajfun farmi winches and with fixed Tigar winch

In Croatia during the last several decades, wood skidding in thinning operations of 50 to 60 years old deciduous forests has been basically performed by adapted farming tractors. As their original use was considerably different, they could not meet all the basic requirements for thinning vehicles regardless the adaptations. Their equipment and adaptation for the operations of wood exploitation implies the installation of protection elements and particularly the installation of the winch. Consequently, the farming tractor becomes a completely new vehicle and apart from a separate statement of technical characteristics of the tractor and winch, technical characteristics of the new tractor assembly should be investigated. This paper describes the morphological analysis and analysis of some other technical characteristics of the farming tractor - Steyr 9078a equipped with three different versions of Tajfun winches, the so-called &laquo ; ; ; farmi winches&raquo ; ; ; (1 x 60 AHK, 2 x 50 AHK and 2 x 60 AHK) installed in the three point linkage of the tractor. Comparison has also been made with the same tractors with a fixed Tigar winch mounted on the rear axle. A survey has also been given of the most significant characteristics of the vehicle dynamic weight distribution in skidding, such as the centre of gravity height, its distance from the rear wheels, the distance between the lead roller and the rear wheels and the distance between the lead roller and the ground. These characteristics have been compared to the characteristics of the family of rubber-tired skidders obtained through their morphological analysis based on the database consisting of more than 90 skidders. All morphological relations have been determined depending on the vehicle mass. According to the investigations it can be concluded that farming tractor equipped with farmi winches, in view of its morphological characteristics, can be classified somewhere between medium-size skidders and skidders. The tractor with farmi winch achieves good results in winching. It has also been established that the position of the centre of gravity of the variants of the adapted farming tractor is less favourable. The variants of the agricultural tractor equipped with farmi winch have a lower centre of gravity than tractors with the winch installed on the rear axle, but the distance of the lead roller from the ground is somewhat higher.

adapted farming tractors; winches; timber skidding; stand thinning; morphological analysis

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