DEVICE FOR FORMING HELICAL PROFILE ON WELL WALLS FOR BORED PILES Russian patent published in 2012 - IPC E21B7/28 

FIELD: construction.

SUBSTANCE: invention relates to construction, namely to devices increasing bearing capacity of bored piles and will find application in construction of foundations for buildings and structures. The device for forming a helical profile on well walls for bored piles comprises a working tip made of sector boards, the upper end of which is hingedly fixed on the body, a vibrator of circular vibrations with a mechanism of sector boards spreading in the form of a ring and a drive of reciprocal motion, installed in the working tip and a mechanism of working tip supply. To the lower end of the sector boards bent inside the working tip there are conical profiles fixed at the angle to the axis of the tip, at the same time the ring of the sector boards spreading mechanism is rigidly fixed on the vibrator body, which is connected by a drive of reciprocal motion with the body of the working tip.

EFFECT: increased bearing capacity of bored piles due to increased adhesion of a side surface of a pile with well walls.

4 dwg