Abstract: The present invention provides a handpiece for dental medical treatment in which a head portion encasing therein an air turbine is detachably mounted on a handpiece body whereby the handpiece body capable of being subjected to high temperature sterilization by boiling is repeatedly used whereas the head portion is discarded after use to maintain the aseptic state of the whole handpiece and positively prevent secondary infection such as AIDS, hepatitis, etc. in an actual medical site. Furthermore, the construction of the air turbine and molding of various parts are simplified so that the head portion can be provided at extremely low cost to effectively prevent infection of AIDS, hepatitis, etc. as mentioned above.

Abstract: The invention is directed to a turbine type air motor adapted for use in a hand-piece for dental treatment and includes an air motor body supported by both ends of a turbine shaft with axle-bearings. The air motor includes an air charging passage for introducing compressed air from the rear end, an air discharging passage provided therein in parallel with the air charging passage, and a collet adapted to detachably load a cutting tool. Air flow in the air charging passage is directed to cool one axle-bearing and other air flow in the air discharging passage is directed to cool the other axle-bearing for locally cooling frictional heat generated in both axle-bearings by the high frequency of the air turbine rotation. The collet is devised to easily load the cutting tool by pushing a knock tube provided in the rear end of the hand-piece.

Abstract: An air motor assembly driven by compressed air for using pencil type handy grinder, comprising an outer jacket casing made of a synthetic resin to cover a metal-made cylindrical housing to house an air turbine cylinder having air jetting nozzles into the turbine rotor thereof and air discharging apertures at opposite side of the air jetting nozzles, the compressed air feeding passages provided along the axis to the air turbine cylinder and the discharged air exhausting passages provided in parallel with the air feeding passages, the feeding air control mechanism including an air valve tube with air communicating orifices and a flange shaped valve, an air controlling knob made of a synthetic resin having double cylindrical structure consisting of an inner cylindrical body and an outer cylindrical body which is to be inserted into the enlarged portion of the outer jacket casing to form the discharged air exhausting passage between the inner and outer cylindrical bodies, and a noise silencing baffler made of a f