Time consumption and productivity of a medium size mobile tower yarder in downhill and uphill configurations: a case study in Czech Republic

Abstract

Cable cranes are among the most important means of yarding and transporting timber in many mountainous regions of Europe. In the last decade, all-terrain mobile tower cable cranes have been increasing due to their adaptability to operate both in uphill as well in downhill configuration. This research assesses the efficiency and the costs of a mobile cable crane manufactured in Czech Republic and designed for all-terrain application and specifically mounted on a wheeled agricultural tractor. A total of 100 cycle times were recorded in order to obtain evaluate the performance in the downhill as well uphill extraction configuration. The productivity analysis was based on regression equation as a function lateral distance, skyline slope distance and extracted volume. Increasing in number of lateral distance and extraction distance resulted as significant variables affecting the cycle time. Even if the test highlights a good efficiency of the extraction system for both the configuration (uphill vs downhill) there a still many organisational features that could be improved in order to fully exploit the potentiality of the tested cable crane system.