Analyzing Slack-pulling Forces in Manually Operated Skyline Logging Systems
Abstract:A model is developed to calculate the main-line tension produced by line resistance caused by ground drag when pulling a cable main line through a clamped skyline carriage by hand. Slack-pulling effort was found to increase linearly with increasing slope along the skyline corridor. An increase in line weight, coefficient of friction, or horizontal distance from the landing to the carriage produced a linear rise in slack-pulling effort. The effect of carriage height is nonlinear but nearly constant with respect to main-line tension at the carriage. Assuming constant main-line tension at the carriage, the main-line tension encountered by a choker setter at the ground decreases linearly with increasing carriage height. Using the model it is possible to establish bounds on feasible distances for hand-pulling slack as a function of crew size. In addition, the determination of main-line tension at the carriage provides a useful parameter for the design of carriages that use mechanical means for pulling slack. Forest Sci. 25:475-484.
Document Type: Journal Article
Affiliations: Research Engineer, Forest Engineering Systems, Southern Forest Experiment Station, USDA, Forest Service, Auburn, Alabama 36830
Publication date: 1979-09-01
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- Forest Science is a peer-reviewed journal publishing fundamental and applied research that explores all aspects of natural and social sciences as they apply to the function and management of the forested ecosystems of the world. Topics include silviculture, forest management, biometrics, economics, entomology & pathology, fire & fuels management, forest ecology, genetics & tree improvement, geospatial technologies, harvesting & utilization, landscape ecology, operations research, forest policy, physiology, recreation, social sciences, soils & hydrology, and wildlife management.
Forest Science is published bimonthly in February, April, June, August, October, and December.
2015 Impact Factor: 1.702
Ranking: 16 of 66 in forestry
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Journal of Forestry
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