Apparatus for forming cast-in-place caseless concrete piles and the like

Apparatus for use with pile driving equipment for forming in the earth a cast-in-place caseless pile of fill material such as concrete or the like introduced in fluid condition into a vertically elongated pile-forming hole in the earth to set upon curing, comprising

• a. a driving tip member adapted to be driven into the ground having a transversely enlarged portion of the cross section and configuration corresponding to that of the desired pile,
• b. a vertically elongated driving mandrel for releasably engaging the driving tip member and for transmitting the driving force of the pile driving equipment to the driving tip member, the mandrel being smaller transversely than the diameter of said transversely enlarged portion and having a cross-sectional configuration that affords a large void area for gravity flow of the fill material downwardly throughout the pile-forming hole, and
• c. movable fill hopper to be disposed in surrounding relation with the mandrel at the upper end of the pile-forming hole forming an upwardly opening receptacle portion having a bottom discharge opening sized to correspond substantially to the maximum cross-sectional area of the driving tip member and receive said mandrel therethrough and having downwardly sloping walls converging to locations closely adjacent the perimeter of said discharge opening for guiding the fill material in said hopper along downwardly converging paths to the discharge opening,
• d. said fill hopper further including a rigid thin-wall tubular sealing skirt joined to and extending downwardly from said walls adjacent the perimeter of the discharge opening in concentric relation to a vertical center axis through said discharge opening and mandrel and having a configuration corresponding to and slightly smaller than the transversely enlarged portion of the driving tip member to telescopically advance to the depth of the skirt under the weight of the hopper into the upper portion of the pile-forming hole as the hole is formed during initial penetration of the ground by the tip member to substantially form a seal with the walls of the hole against lateral flow of fill material along the ground surface, said fill hopper including a plurality of radial substantially planiform partitions lying in vertical radial planes relative to the axis of the mandrel and discharge opening joined along their radially inner edges to a cylindrical annular wall member joined to said downwardly sloping walls at the perimeter of said discharge opening to define a plurality of substantially like capacity subdivision compartments of said receptacle portion each adapted to receive a predetermined quantity of flowable fill material therein, and fill material discharge control means provided for each of said compartments movable between closed and open positions for permitting the pile-forming hole being formed by the driving mandrel and tip member.