This SAE Standard provides a uniform method to calculate the lift capacity of knuckle-boom log loaders and certain forestry equipment. It establishes definitions and specifies machine conditions for calculations. This document applies to knuckle-boom log loaders as defined in SAE J1209 and SAE J2055 and certain forestry equipment defined in SAE J1209 that have a rotating upper-structure such as feller bunchers, forwarders, harvesters, and behind the cab or rear-mounted knuckle-boom log loaders not having their own power supply. It does not apply to harvesters that are incapable of lifting a tree or log completely off the ground. This document applies to those machines that are crawler, rubber-tired, and pedestal or stationary mounted.

Purpose—The purpose of the SAE document is to establish a consistent, repeatable means of determining the lift capacity for the types of equipment contained therein.

Applicability—Lift capacity calculations and the resulting rated lift capacity chart are developed by the equipment manufacturer or the entity that assembles and or modifies basic components to produce the complete machine for each machine model that is produced. These charts are developed solely for comparative purposes.