International Grapple/Carriage Developments: Literature Review

In:

Harvesting Technical Reports

Report No:

H004

Report Date:

March 2, 2011

Author(s):

T Evanson

This report reviews international literature on developments in cable harvesting grapples and carriages. It contributes to the programme of research initiated by Future Forests Research (FFR) which aims to direct the New Zealand forest industry towards productivity gains and cost reduction through the use of improved harvesting technologies. Prior to development of new technologies in improved grapple/carriage control systems and advanced hauler vision systems, a review of international literature was undertaken to define the state of the art in these areas and to contribute to the problem definition stage of the project.

The literature review covers previous research in mechanical. motorised and self-propelled skyline carriages, and developments in tower and swing yarders, and innovative yarding systems. The review concluded that larger capacity grapples and carriages are manufactured only in North America. Recent innovations included multi-speed transmissions and hydraulic powered slack pulling carriages and the use of cameras to help the yarder operator spot the carriage or grapple. Smaller capacity carriages (but no grapples) were used in European operations, and the yarder-carriage control systems for Processor-Tower-Yarder (PTY) systems were found to be well advanced. Combinations of these developments may have application in New Zealand clearfell cable yarding operations to enable wider haul corridors to be logged, reducing the number of rope shifts, and to exploit the possibility of extracting bunched tree stems.

Document:

H004 (863.59 Kb)