Patent ID: 7429154

Claim:
An insertion end of a tool driven along an axis in at least one of partially rotary movement and percussive movement, the insertion end comprising: a longitudinally extending member having: a longitudinal axis; a maximum guide diameter; at least one locking groove longitudinally closed at a locking end towards a free leading end; and at least one rotary driving groove having at least one tangential force contact surface; wherein the at least one rotary driving groove is arranged on the tool-side ahead of the locking end; and wherein the at least one rotary driving groove has a width equal to at least one fifth of the guide diameter; wherein a combined length of the at least one rotary driving groove and the at least one locking groove is equal to at least three times the guide diameter; wherein a contact length of the at least one rotary driving groove is equal to at least 1.5 times the guide diameter.