Abstract: A transmission device for use in a dental handpiece has a modular unit comprising an input shaft coaxial to and driven by the motor shaft, and an oblique shaft extending obliquely with respect to the input shaft and also to the tool driving shaft. Each end of the oblique shaft carries a bevel pinion, one bevel pinion meshing with a bevel wheel fixed to the input shaft and the other bevel pinion meshes with another bevel wheel fixed to the tool driving shaft. The input and oblique shafts are mounted in suitable bores formed in a socket, the oblique bore remaining without the peripheral limits of the socket. The socket is adapted to be forcibly fitted into the handle of the handpiece.

Abstract: System of coupling of the head of a drive unit to the body of a driven unit, characterized in that, the head bears a longitudinal key having two slopes inclined in relation to the axis of the head, and the body has a guiding or key-way groove for this key, this groove opening on an annular clearing in which a segment can be rotated against a spring and in which a pin is fastened radially, so that, while the key is engaged, this pin, by cooperation with the first of the slopes controls the rotation of the segment, then by cooperation with the second slope controls the blocking of the head in its driving position, and the segment can also be operated by hand so as to free the pin and allow the withdrawal of the head by drawing the key rearwardly.

Abstract: A hand-held implement for removing dental scale provided with a rigid shaft to which is applied vibrations in a rotational or circumferential direction by a dynamically unbalanced air driven turbine. The rotor of the turbine is coupled to the shaft by a bearing and the shaft is restrained from rotating and restrained axially. Provision is made for supplying cooling water through the shaft to a dental scale removing tool mounted on a free end of the vibrated shaft.

Abstract: This dental handpiece comprises means for controlling the delivery of compressed air and water to an outlet conduit leading to the head of the handpiece. The water and air supply conduits from the motor open each into a circular groove formed in the inner periphery of a socket easily fitted on the tool holder retaining end of the motor. Radial ports formed in the socket open on the one hand into the grooves, respectively, and on the other hand into an annular chamber formed between the socket and the handpiece body, the outlet conduit extending from this chamber. A rotary ring accessible from outside the handpiece body is provided with a pair of seals off-set axially and angularly to each other and so arranged that in two end positions of the ring one of the two supply conduits is closed while the other conduit is open, and that in an intermediate position both conduits are open.