摘要 |
A broaching tool has a needle-shaped working portion (2) and a shank portion which is shaped for attachment in the distal end (18) of a drive bar (12) of a drive instrument for the tool. The shank portion of the tool has at least one bend (8) and preferably also a second oppositely directed bend (10). A proximal end (14) of the drive bar (12) of the drive instrument is adapted to be coupled to a vibratory element (16) which, thereby, is able to generate longitudinal high frequency vibrations in the drive bar (12). The distal drive bar end (18) is angled (B) about an axis (22) which acts as a hinge having a certain rigidity of bending. By adapting and matching a. o. the angle (B) and the bends (8, 10) in the tool, it is possible to compensate away distructive natural oscillations in the tool which, thereby, can be powered and used with high working frequencies without risk of fatigue fractures in the material of the tool. |