DRILLING CROWN Russian patent published in 2014 - IPC E21B10/02 F16B39/06 

FIELD: mining.

SUBSTANCE: invention refers to crowns intended for drilling of fractured rocks and rocks that are interstratified as to hardness. A drilling crown includes a housing with slots for transportation of destructed rock, with an annular projection on a lower end face and with replaceable sectors reinforced with concentrically located cutters and fixed on the housing by means of fasteners with a faceted head. Each replaceable sector is equipped with a retainer made in the form of a stepped rod spring-loaded in an axial direction and provided at least with one flat face on the side of its external end face, which interacts when in an operating position with the flat face of the working head of the fastener; besides, the retainer is arranged in a channel made in the sector housing and secured in it against being turned; besides, distance between axes of the retainer and the fastener is shorter than sum of radii of the retainer and the head of the fastener.

EFFECT: crown ensures improvement of operating efficiency of a drilling crown.

2 cl, 3 dwg