This standard applies to hydraulically operated backhoes (see SAE J49). This standard describes a uniform "over end" and "full swing arc" lifting capacity rating for backhoes. It is based on the actual capacity of the machine to lift and support a load under stable conditions. Rated lift capacities will be specified for both the boom and the dipperstick and will be shown on a lift capacity chart (see Fig. 1).
This revision of existing SAE J31 has been expanded to include a calculated method of determiningin lift capacities. This is a common practice in the industry and is also used on similar equipment such as hydraulic excavators.