Abstract: An apparatus is provided that performs continuous cleaning of a surface of a grounded material which is coated with an organic substance. The apparatus includes a plurality of electrodes covered with a dielectric and disposed along the surface of the material. The electrodes are connected to a high-voltage generator using a MOS power transistor connected to a step up transformer to convert low-voltage pulses generated from a low-voltage power supply into high-voltage pulses. The apparatus is configured to provide a pulsed electric field wherein the maximum voltage of the positive pulses U+ is greater than the arc-striking voltage Ua, and the maximum absolute value of the voltage of the negative pulses U? is less than the striking voltage Ua.

Abstract: A method for the continuous cleaning of the surface of a material (2) which is coated with an organic substance. Steps of the method are: introducing the material (2) into a treatment area which is supplied with a gas stream containing oxygen; earthing the material (2); and generating a plasma by imposing an electric field between the surface of the material (2) and at least one dielectric-covered electrode (3), the electric field being pulsed and providing a succession of positive and negative voltage pulses in relation to the material (2). Moreover, the maximum voltage of the positive pulses U+ is greater than the arc-striking voltage Ua, and the maximum absolute value of the voltage of the negative pulses U? is less than the striking voltage Ua. Also, a generator and a device which are used to carry out this method.

Abstract: A method for the continuous cleaning of the surface of a material (2) which is coated with an organic substance. Steps of the method are: introducing the material (2) into a treatment area which is supplied with a gas stream containing oxygen; earthing the material (2); and generating a plasma by imposing an electric field between the surface of the material (2) and at least one dielectric-covered electrode (3), the electric field being pulsed and providing a succession of positive and negative voltage pulses in relation to the material (2). Moreover, the maximum voltage of the positive pulses U+ is greater than the arc-striking voltage Ua, and the maximum absolute value of the voltage of the negative pulses U? is less than the striking voltage Ua+. Also, a generator and a device which are used to carry out this method.

Abstract: The invention relates to a method for the continuous cleaning of the surface of a material (2) which is coated with an organic substance. The inventive method comprises the following steps, consisting in: introducing the material (2) into a treatment area which is supplied with a gas stream containing oxygen; earthing the material (2); and generating a plasma by imposing an electric field between the surface of the material (2) and at least one dielectric-covered electrode (3), said electric field being pulsed and comprising a succession of positive and negative voltage pulses in relation to the material (2). Moreover, the maximum voltage of the positive pulses U+ is greater than the arc striking voltage Ua and the maximum absolute value voltage of the negative pulses U? is less than the striking voltage Ua. The invention also relates to a generator and a device which are used to carry out said method.

Abstract: A device for stepping down and/or stepping up the speed of rotation of a motor element, such as a dental micromotor, includes two toothed pinions with common axes of rotation and which are mounted in a support piece. The support piece can turn through an angle (.alpha.) with respect to the body o the motor element about an axis (A) parallel with an axis (o) of the input pinion of the device and offset with respect to the axis (o) by a distance (OA). The axis (A) is further offset with respect to the axis (O') of rotation of the output pinion by a distance (AO') equal to the distance (OA). As a result, in a first position, the axis (O') is merged with the axis (O), and a first one of the pinions (or a crown wheel) is meshed with elements upstream of the kinematic chain. In a second position, following rotation of the support piece through a defined angle (.alpha.

Abstract: Automatic apparatus for cleaning dental handpieces and turbines is in the form of a housing having a compartment with hinged door. Standard motor noses project down from the top of the compartment to receive handpieces or turbines to be cleaned. Cleaning fluids, namely water, a disinfectant and oil are supplied sequentially to the motor noses while internal shafts of the motor noses are rotated by a set of pinions to drive the handpieces or turbines while the fluids are passed through them. The hinged door has an inflatable tube seal.

Abstract: This device comprises a dental handpiece (15), notably a contra-angle, detachably coupled to a socket (35) so that the handpiece can rotate freely relative to the socket, this socket incorporating a micromotor for driving the dental treatment tool. The handpiece comprises means for illuminating the treatment area and the electric power supply between the two elements is taking place by means of spring loaded contact pistons (19, 22) parallel to the handpiece axis and projecting from the front face of one of the two elements, the contact pistons being adapted, in the coupled condition, to be urged against corresponding annular electric tracks (18, 21) provided at the end of the other element, these tracks being insulated from each other by a ring (20).

Abstract: The laser comprises a gas-filled channel (51) extending between a pair of metal plates (2 and 3). The laser is excited by a spark discharge through the gas from one plate to the other. The energy for the spark comes form a pair of built-in capacitors extending between the plates on either side of the channel. The plates constitute the plates of the capacitors, and apart from a plastic retaining wall (37, 39) round each capacitor, the capacitor dielectric is water. The water is advantageously pumped (47) round a cooling circuit (48), and it is not permanently damaged if an accidental discharge takes place through the water. The invention is particularly applicable to nitrogen and to excimer lasers.

Abstract: A gas laser in which the gas is excited by laser discharge, said laser including two capacitors formed by two parallel metal plates (2, 3) between which two dielectric parts (4,5) are spaced apart to form a passage (6) which contains the laser gas. It further includes a transformer (13) whose secondary winding (12) is connected to the plates and whose primary winding (14) is connected in series with a capacitor (15), means (17) for charging and capacitor and a thyristor (16) for discharging the capacitor in the primary winding. Application to exciting gas lasers in which the gas contains a dye stuff.

Abstract: A device for connecting to the body of a dentistry counter-angle the unit for transmitting the rotary movement of the major axis of the counter-angle to the oblique shaft contained in the head of the counter-angle. The transmission assembly is placed inside a socket (5), forming a case, the socket itself being fixed to the body of the counter-angle by means of a bayonet attachment, consisting of at least one pin (16), fixed to the inner wall of the body of the counter-angle, and of at least one L-shaped slot (12), formed on the socket. Application to the rapid assembling and dismantling of dentistry equipment.

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: The invention concerns a device for treating a laser light pulse and comprises, aligned successively on a same axis, a polarizer, an optical rotator, semi-reflecting plates and a reflector. The device can be applied to high-power lasers.

Abstract: Gas laser comprising a flat electric energizing line consisting of an insulating layer inserted between two metallic layers brought to different potentials, one of whose edges is cut out in the shape of a parabola, one slot being provided in one of the layers, an active gaseous medium flowing in the slot, a circuit for setting up a substantially punctiform discharge between the metallic layers at the level of the focus of the parabolas. The electric line is arranged on a massive plate comprising on the one hand a cut provided in its lower face substantially opposite the slot and communicating with the latter and on the other hand two grooves provided on its upper face each having fitted in it a flexible seal and arranged opposite the walls of the slot.