DEVICE FOR DRILLING HOLE FOR BORED SCREW PILE FORMING Russian patent published in 2005 - IPC

FIELD: building, particularly for hole drilling in stable sedimentary rocks during building concrete and reinforced concrete piles having high load-bearing capacity and adapted for foundation and anchoring support forming.

SUBSTANCE: device has immovable unit fixed relative ground during drilling operation and installed on vehicle, and movable unit moving over immovable part for hole drilling. Immovable unit has steel tubular body closed with steel caps from both sides thereof. Four guiding channel bars and two threaded bars are arranged inside the tubular body. Movable unit has drilling shaft including threaded drill made as steel tube with two differently sized cutters. The cutters are of dihedral shape and have common rib and orifices formed in the steel tube under the cutters. Area of ground cut by lesser cutter is twice as small as that cut by larger cutter. Auger drill comprises removable cutting part and auger member communicating with collapsible box-shaped sleeve in upper auger member part through outlet orifice. Movable unit has platform fixedly secured to drilling shaft and comprising steel body and steep plates. Installed on the platform are driving mechanism for threaded drill and platform and driving mechanism for auger drill. Both driving mechanisms include electric drive and gear wheels. During hole drilling threaded and auger drills are installed to rotate in mutually perpendicular directions so that auger drill may perform not less than 20 revolutions as threaded drill turns through 360°. Threaded drill rotation is accompanied with longitudinal movement thereof for distance equal to thread pitch c=1.414d, where d is outer diameter of threaded drill tube. During threaded drill rotation through 360° the greater cutter tip describes a circle having diameter D=2.414d and equal to hole diameter.

EFFECT: possibility to drill screw-like hole with coarse thread in one pass or in one working cycle.

4 cl, 23 dwg