US Patent 9416513 Helical screw pile and soil displacement device with curved blades

A helical screw pile having a soil displacement device (lead displacement plate) on its shaft above at least one helical plate, which pulls the pile into the ground when the shaft is rotated. The lead displacement plate has a disk that carries at least two curved, axially extending bottom blades, which preferably extend beyond the disk periphery. The axial height of the blades preferably is greater than the axial pitch of the helical plate(s) divided by the number of blades. The top of the disk has an axially extending adapter ring that defines an annular seat for centering a tubular casing. Extension displacement plates can be used between extension shafts for centering additional tubular casings.