Patent ID: 7832504

Claim:
A bit assembly for a percussive drill, the drill including a casing with an interior chamber, the bit assembly comprising: a bit connectable with the casing and having a longitudinal bore and an axis extending centrally through the bore, the bore having a retainer portion with a retainer portion inner surface including at least one generally conical inner surface extending circumferentially about and facing generally toward the axis, the conical inner surface providing a majority of the retainer portion inner surface; and a generally cylindrical valve having a longitudinal passage, the passage having an inlet fluidly connectable with the casing chamber and an outlet fluidly connectable with the bit central bore, an axis extending centrally through the passage, and an engagement portion with an engagement portion outer surface including at least one generally conical outer surface extending circumferentially about and facing generally away from the valve axis, the conical outer surface providing a majority of the engagement portion outer surface, the valve engagement portion being disposeable within the bit bore retainer portion such that the valve conical outer surface is disposed within and against the bit conical inner surface so as to retain the valve coupled with the bit.