Therefore, it is the principal object of the present invention to provide dental handpieces
of the type described above in which the problems and disadvantages of the solutions described above are eliminated.
According to the present dental equipment, at least one opening in the turbine chamber wall in the area near the axis is connected via a connecting conduit to the return conduit.
According to a first embodiment which is based on the same basic solution, the connection ends of the duct receiving drill head dental handpiece high speed on the side of the tool holder on the side of the tool. As a result of this measure, when the turbine runs out air after the drive has been stopped, the turbine continues to rotate a flow of air enclosed in the periphery of the rotor through the return duct, the connecting duct and opening near the axis of the turbine chamber, in which this configuration ensures that virtually no air is taken inside the handpiece along the tool axis and through bearings rollers. Accordingly, when the handpiece is again not have impurities are expelled from the interior of the handpiece.
According to a further advantageous development of the first embodiment described above, the turbine chamber is constructed in the area of the opening for the connection conduit of an annular chamber which communicates with the actual turbine chamber only through an annular opening around the shaft. This has the advantage that only a very small amount of air flowing out through the connecting conduit during operation, due to the centrifugal acceleration causes air propulsion to guide the periphery of the turbine chamber and significantly lower pressure there is an excess in the area near the axis than in the periphery of the rotor. Thus, the measure according to the present dental autoclave only insignificantly impairs the efficiency of the turbine.
The various features of novelty which characterize the low speed air motor dental handpieces
are pointed out with particularity in the claims annexed to and forming part of the disclosure. For a better understanding of the invention, its operating advantages, specific objects attained by its use, reference should be given to the drawing and descriptive matter in which are illustrated and described preferred embodiments of the invention.