Patent ID: 7329123

Claim:
An air-driven cutting device for a medical treatment, the cutting device comprising: a hand piece including a head portion receiving a rotary cylinder for holding a cutting tool and a turbine blade mounted around and secured on the rotary cylinder so that an air fed from an air-supply by an air-supply passage is applied onto the turbine blade to rotate the turbine blade and then exhausted from an exhaust passage; wherein the head portion has a first chamber which is located at a portion confronting the outer peripheral end portion of the turbine blade and which extends in a direction orthogonal to the central axis of the rotary cylinder and between the air-supply passage and the exhaust passage as said air-supply and exhaust passage run through said had piece, and at least one second chamber which is located adjacent to at least one end of the turbine blade along an axial direction of the turbine blade and which communicates with the first chamber, and wherein the first chamber is formed inclining in the rotating direction of the turban blade relative to a line orthogonal to the central axis.