Development and Evaluation of a Hydraulic Hole Digger for Spot Treatment of Landscapes and Orchards

The most common types of post hole diggers are the auger styles including the engine powered and tractor mounted types which neither are applicable in current situations of Iran. In this study a hydraulic driven post hole digger was developed which is applicable in restricted spaces and has the ability of digging 15-20 cm wide holes to a depth of 50 cm. In contrast to tractor and engine powered types, in the developed machine the auger is screwed down at a relatively slow rotational speed under a vertical force and the soil compacted between the auger’s flights is brought out of the hole as the auger is lifted. In order to choose an appropriate auger for this machine three types of spiral augers with conical tips (two size of flights pitch) and flange tip and a cylindrical type were evaluated. The results showed that spiral augers with conical tip, the lowest energy consumption and time requirement was the most appropriate for this digger. I order to have a better evacuation of holes in hard and frictional soils, augers with smaller pitch are recommended whereas bigger pitches of auger are more appropriate for sticky soils to avoid soil compaction between the auger’s flights.