DIGITALNA ARHIVA ŠUMARSKOG LISTA
prilagođeno pretraživanje po punom tekstu
| ŠUMARSKI LIST 5-6/2021 str. 22 <-- 22 --> PDF |
Summary Based on the dimensional characteristics of the cable skidder (dimensions, weight, position of the center of gravity), a model was developed for estimating the mobility of the skidder during timber extraction (skidding) uphill in a safe, efficient and environmentally sound way. The model is based on the limiting slope of skidders’ mobility depending on the traction performance of the vehicle, which connects two research approaches, 1) vehicle – terrain (distribution of forces depending on the slope and load) and 2) wheel – soil (traction performance based on wheel numeric). The model is in compliance with a number of restrictions arising from previous research: i) unloading the front axle of the vehicle, ii) overloading the rear axle of the vehicle, iii) minimum longitudinal stability of the skidder, iv) minimal soil bearing capacity and v) allowed tyre load capacity. The results of the mobility of the cable skidder Ecotrac 55V equipped with 12.4-24 tires during skidding timber uphill, differ significantly with regard to the load-bearing capacity and the load size. For smaller loads, weighing up to 1 ton, the mobility of the skidder is determined by the criteria/limits of the skidder gradeability (traction performance) and environmental benefits (minimum load-bearing capacity). As the weight of the load increases, apart from the load-bearing capacity, the decisive limiting factor of mobility becomes the load ratio of the front and rear axles of the vehicle (> 1: 3.5), which limits the mobility of the skidder on slopes <33% for loads of 1.5 tons, <20% for 2 tons. At a load of 2.5 tons, the mobility of the skidder is affected by the criteria of the maximum allowable load of the rear axle of the skidder on slopes <7%. Key words: cable skidder, uphill skidding, gradeability, traction performance |