Monitoring Cable Tensile Forces of Winch-Assist Harvester and Forwarder Operations in Steep Terrain

Franz Holzleitner,Maximilian Kastner,Christian Kanzian,Karl Stampfer,Norbert Höller

doi:10.3390/f9020053

Franz Holzleitner, Maximilian Kastner + Show 3 more

Open Access

https://doi.org/10.3390/f9020053

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Abstract

The objective of this case study was to develop and test a specific survey protocol for monitoring tensile forces for winch-assisted harvesters and forwarders with a mounted or integrated constant-pull capstan winch technology. Based on the designed survey protocol, the interactions between work phases, machine inclination, and tensile forces in typical work conditions were analysed. The established workflow, including equipment and the developed analysis routines, worked appropriately and smoothly. The working load on the cable during the study did not exceed 50% of the maximum breaking strength. A maximum tensile force peak at 56 kN was observed during delays for the forwarder, and a peak of 75.5 kN was observed for the harvester, both of which are still within the safe working load when considering a safety factor of two.

Highlights

In steep terrain cable yarding combined with motor manual felling is still the most appropriate harvesting system to use [1]
A maximum tensile force peak at 56 kN was observed during delays for the forwarder, and a peak of 75.5 kN was observed for the harvester, both of which are still within the safe working load when considering a safety factor of two
The maximum tensile force once reached a peak of 75.5 kN during felling and processing, which is still below the maximum safe working load of 50% considering the 14-mm diameter of the mounted cable

Summary

Introduction

In steep terrain cable yarding combined with motor manual felling is still the most appropriate harvesting system to use [1]. Winch-assisted harvesting machinery offers new opportunities in terms of cost efficiency and increased safety on steep terrain [2,3]. Mounted or integrated cable winches for harvesters or forwarders could offer entrepreneurs new possibilities to increase their portfolio and machine utilization due to providing a wider range of available harvesting operations. The soil-tire interaction has been described in detail in terms of the interaction of forces and slip while driving on slopes according to different soil types and water content [7,8,9,10]. The maximum trafficable grades without winch assist for different soil conditions have been reported. Wijekoon [11] investigated the soil-tire interaction in terms of number of passes, the ground pressure, and rut depths of forest machines. The needed improvements for controlling a cable-towed vehicle to minimize slip control in timber harvesting operations were investigated by Salsbery and Hartsough [13]

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