Multi-span skyline logging system

Abstract

An arcuate jack is arranged to be secured to a spar for supporting a skyline over it. A carriage assembly comprises a main carriage arranged to travel on the skyline and a secondary carriage supported on the main carriage for movement between leading and trailing ends of such main carriage. A brake is operative between the main and secondary carriages to control movement of the secondary carriage on the main carriage. The secondary carriage supports a drop line for connection to a load, and a mainline is connected to the secondary carriage for pulling the carrige assembly along the skyling. A guide for the mainline is provided on the spar and is disposed below the jack in an arrangement whereby the pull on the carriage assembly from the mainline is substantially tangent to the arcuate contour of the jack at its entrance end. The brake is arranged to hold the secondary carriage at the trailing end of the main carriage during initial movement of the latter onto the jack and in subsequent movements thereof along the jack to release it for movement toward the leading end of the main carriage, thus providing a weight shift that assists movement of the carriage over the jack. A clearance cam is provided which is arranged to be engaged by the carriage assembly and which is arranged to swing the carriage assembly out at the bottom so that the drop line will bypass the guide.

Dependencies are inferred from the claim text.