Twist drill
AssigneeHilti Aktiengesellschaft
InventorsRobert S. Saitta, Troy D. Wells, Christian Putzi
Life of this patent
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Abstract
A twist drill including a spiral-forming hollow shaft (3) having a spiral-shaped inner surface, and drilling head(5) and shank (6) connected with the shaft (3) at its opposite ends, respectively; and a method for forming such a twist drill.
Claims10
A twist drill, comprising a hollow shaft forming, at least partially, a spiral (2) and having a spiral-shaped inner surface;
- a drilling head (5) provided at one end of the shaft (3), having a cutting bit (4) formed of a hard material, and having, with respect to the cuffing bit (4), a triagonal symmetry with respect to a drill axis (A), and a shank for securing the twist drill in a hand-held tool for joint rotation therewith and with a possibility of a limited axial displacement therein.
A twist drill, comprising a hollow shaft forming, at least partially, a spiral (2) and having a spiral-shaped inner surface;
- a drilling head (5) provided at one end of the shaft (3) and having a cutting bit (4) formed of a hard material;
- and a shank for securing the twist drill in a hand-held tool for joint rotation therewith and with a possibility of a limited axial displacement therein, wherein an outer cross-sectional profile of the spiral (2) includes a plurality of spiral grooves, and a profile of each spiral groove forms a concave curve.
A twist drill, comprising a hollow shaft forming, at least partially, a spiral (2) and having a spiral-shaped inner surface;
- a drilling head (5) provided at one end of the shaft (3) and having a cutting bit (4) formed of a hard material;
- and a shank for securing the twist drill in a hand-held tool for joint rotation therewith and with a possibility of a limited axial displacement therein, wherein the hollow shaft (3) is filled at least partially with viscoelastic material (10).
Dependencies are inferred from the claim text.