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

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.

[1]  F. Bourrier,et al.  Predicting load path and tensile forces during cable yarding operations on steep terrain , 2016, Journal of Forest Research.

[2]  J. Sessions,et al.  Theoretical Stability and Traction of Steep Slope Tethered Feller-Bunchers , 2017 .

[3]  Jörg Hittenbeck.  Estimation of Trafficable Grades from Traction Performance of a Forwarder , 2013 .

[4]  Bruce R. Hartsough,et al.  Control of a cable-towed vehicle to minimize slip , 1993 .

[5]  Karl Stampfer,et al.  Expanding Ground-based Harvesting onto Steep Terrain: A Review , 2015 .

[6]  Sven-Ăke Axelsson,et al.  The Mechanization of Logging Operations in Sweden and its Effect on Occupational Safety and Health , 2013 .

[7]  Ulf Sellgren,et al.  Forest Machine Tire-Soil Interaction , 2012 .

[8]  Karl Stampfer,et al.  Automatic recognition of work phases in cable yarding supported by sensor fusion , 2018 .

[9]  Karl Stampfer,et al.  Utilization Rates and Cost Factors in Timber Harvesting Based on Long-term Machine Data , 2011 .

[10]  Hans Rudolf Heinimann,et al.  Perspectives on Central European Cable Yarding Systems , 2001 .

[11]  R. D. Wismer,et al.  Off-road traction prediction for wheeled vehicles , 1973 .

[12]  Reiner Nollau,et al.  ARE FOREST OPERATIONS ON STEEP TERRAIN (AVERAGE OF 70% SLOPE INCLINATION) WITH WHEEL MOUNTED FORWARDERS WITHOUT SLIPPAGE POSSIBLE? , 2003 .

[13]  Ola Lindroos,et al.  Drivers of Advances in Mechanized Timber Harvesting – a Selective Review of Technological Innovation , 2017 .