Ultrasonic annular core bit

A core bit for an abrasive cutting of mineral components, comprising a cylindrical tube (3) provided at an end surface thereof with one of cutting bodies and abrasive bodies (2);

• and a cover (4) provided at an opposite end surface of the cylindrical tube (3) and secured thereto and having, along a central axis (A) thereof, a shank (5) to be received in at least rotary power tool,
• wherein the cover (4) is dimensioned, with respect to a set excitation frequency, for forming a whole number of maximum amplitude oscillations of a concentric flexural oscillation,
• wherein the cylindrical tube (3) is dimensioned, with respect to said set excitation frequency, for forming a whole number of maximum oscillations of axial longitudinal oscillations,
• wherein the cover (4) has a concentric projection (9) in a vicinity of a location of a nodal circle (7) of amplitude oscillations of the concentric flexural oscillation (8),
• wherein the cover (4) has a concentric projection (9) in a vicinity of a location of a nodal circle (7) of amplitude oscillations of the concentric flexural oscillation (8), and
• wherein the cylindrical tube (3) has, solely in an axial region (X) of axial longitudinal amplification oscillation nodes (1), a plurality of elongate recesses (11) oriented along the central axis (A) and equidistantly arranged over a circumference of the cylindrical tube (3).

A core bit for an abrasive cutting of mineral components, comprising a cylindrical tube (3) provided at an end surface thereof with one of cutting bodies an abrasive bodies (2);

• and a cover (4) provided at an opposite end surface of the cylindrical tube (3) and secured thereto and having, along a central axis (A) thereof, a shank (5) to be received in at least rotary power tool,
• wherein the cover (4) is dimensioned, with respect to a set excitation frequency, for forming a whole number of maximum amplitude oscillations of a concentric flexural oscillation,
• wherein the cylindrical tube (3) is dimensioned, with respect to said set excitation frequency, for forming a whole number of maximum oscillations of axial longitudinal oscillations, and
• wherein the cover (4) has a collar (12) projecting radially beyond the cylindrical tube (3), and
• wherein the collar (12) projects radially beyond the cylindrical tube (3) by a one-fourth of a wave length of the flexural oscillation (8).