Twist-drill bit
AssigneeHilti Aktiengesellschaft
InventorsWerner Kleine, Hans-Werner Bongers-Ambrosius
Life of this patent
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Abstract
A helical drill bit (1) for rock has an axially extending shank (2) located between a chuck insert end (3) and an opposite drilling head (4) with at least one axially extending helical discharge groove (7) extending radially inwardly from the outer circumferential surface of the shank. A radially projecting groove reinforcement (9) is arranged in the base of the radial groove (8), with the reinforcement changing its geometric form or its position within the discharge groove (7) along the discharge groove (7).
Claims9
A helical drill bit for drilling in rock comprising an axially extending shank (2) with a chuck insert end (3) at one end and a drilling head (4) at the other end, said shank having at least one axially extending helical discharge groove (7), said groove (7) having a base (8) spaced radially inward from an outer circumferential surface of said shank with a groove reinforcement extending radially outwardly from the groove base (8), and the position and/or geometric form of said groove reinforcement (9) varying in the axial direction of said discharge groove (7), said shank having a helical land forming the outer circumferential surface of said shank, said groove reinforcement (9) has the location thereof in said groove (7) defined by a rib lead angle (β) differing slightly from a lead angle α of said helical land.
A helical drill bit for drilling in rock comprising an axially extending shank (2) with a chuck insert and (3) at one end and a drilling head (4) at the other end, said shank having at least one axially extending helical discharge groove (7), said groove (7) having a base (8) spaced radially inward from an outer circumferential surface of said shank with a groove reinforcement extending radially outwardly from the groove base (8), and the position and/or geometric form of said groove reinforcement (9) varying in the axial direction of said discharge groove (7), wherein said groove reinforcement is formed of discontinuous reinforcement ribs spaced apart in the helical direction.
Dependencies are inferred from the claim text.