Patent ID: 6270345
Filing Date: 2001-08-07
Classification: A61C

Abstract:
An arrangement for driving a rotary dental or medical tool comprising:a source of pressurized gas;a handpiece that includes a handle and a head, which is attached to the handle;a rotary vane motor, to which the tool is attached and which is mounted within the head of the handpiece; andan inlet conduit leading the pressurized gas to the vane motor;a cylindrical rotor;a cylindrical stator with an eccentric, cylindrical, longitudinally extending bore, in which the rotor is mounted, the rotor and stator being concentric about a longitudinal axis, which is the axis of rotation of the rotor;a plurality of unbiased vanes mounted in corresponding, substantially lengthwise-extending slots formed in the rotor, the unbiased vanes being substantially freely movable in their respective slots in a radial direction that is perpendicular to the axis of rotation;an inlet port and an outlet port formed as openings through the statorin which:an annular space between an outer surface of the rotor and an inner surface of the bore of the stator is uninterrupted, an air bearing thereby being formed between a radially outermost tip surface of each vane and an inner surface of the bore of the stator when the rotor rotates within the stator.