First, the hydraulic excavator enjoys tooth forces of the shovel because the dipper is attached to the machine with a dipperstick and boom, and can often actually realize greater tooth forces than a shovel because of the prize action of the dipper in hard digging.
Digging range can be as deep as 35′ while dumping range in a 360°circle, can be as high as 26′ and this dump range circle can have a radius of 47′ with the current production machine. There are a variety of machine sizes. Generally speaking, the larger bucket machines have greater reach and digging depth. Also the larger mining type hydraulic machines can have special shorter range booms with correspondingly larger dippers. A new bigger machine with more than 60ft. of reach and 40 ft. digging depth is now at work in Wisconsin.
All excavators have a duty cycle rating. This is not lift capacity, rather it is a complex judgment by the manufacturer of considerations that allow the largest load of material or widest dipper for digging, considering tooth force for penetration, that the machine can reasonably live with for long economic and reliable service life. The duty cycle rating must take into consideration the dipper weight and width, as well as the material characteristics and loose weight. All dippers should be considered to carry some degree of “heap” in calculating the weight of the material.
