a machine designed for stacking and loading lumber on logging vehicles, broad-gauge rolling stock, and barges and ships. Timber loaders are subdivided into loader-stackers, cranes, and cable units.
Loader-stackers are mobile vehicles with a caterpillar track or wheels whose lever-operated claw mechanisms have mechanical or hydraulic drive, which eliminates the need for manual labor in the formation, securing, and release of stacks, tree-length logs, or assorted pieces. Timber loaders are used in loading lumber at the forest sites and also in unloading, stacking, and loading timber at lower woodyards.
The cranes may be of the cantilever-gantry, gantry, tower, or jib type. The first three types of cranes are used at lower wood-yards and timber-transshipping stations, whereas jib cranes are used primarily at forest loading sites and occasionally at lower woodyards. All the cranes are equipped with either chokers for grabbing lumber stacks or claws, thus totally eliminating manual operations in stacking and loading work.
Cable units (jib and horizontal) such as winches and cable cranes are being replaced at upper woodyards by loader-stackers and at lower woodyards by gantry and tower cranes and selfpropelled loaders.
D. K. VOEVODA