EP0277047A2 - Device assuring electrical contact in an apparatus generating high-frequency pulses or shock waves - Google Patents

Abstract

The invention relates to a device ensuring improved electrical contact between an electrical conductor (12) and an electrode (14). This device is characterised in that it comprises an element (50) forming a fixed position contact nut, an electrically conductive material, containing an axial through orifice (52) into which passes the electrode (14) or an electrode-holder element (16), this electrical conductor (12) finishing up at the nut-forming element (50) with a connection stem (54). This nut-forming element (50) can be constructed as two half-discs (50a,50b). In this way there is obtained an assembling and disassembling facility, as well as improved electrical contact during operation. <IMAGE>

Description

The invention relates essentially to a device ensuring improved electrical contact between an electrical conductor and an electrode or an electrode-carrying element, the use of this device in any device for advancing an electrode or an electrode-carrying element and the incorporation of this device ensuring electrical contact in a device generating high frequency pulses or shock waves.

Apparatuses generating high frequency pulses, or shock waves, also called lithotripsers have been known for many years. Some devices include a device for concentrating the pulses on a target focus, can be in particular a truncated ellipsoidal reflector as described in US Patent RIEBER ^No. 2,559,227.

A similar device is described in document FR-A-2 247 195.

The pulses or shock waves are generated by a discharge or an electric arc between two electrodes which can be made of highly conductive material such as copper or brass and which are mounted on an insulating support.

The discharges generated at the electrodes are usually accompanied by metal tearing which leads to rapid wear of the electrodes which have to be changed relatively often.

To remedy this wear, there has already been proposed in document EP-A-124 682 a device for advancing the electrodes 36, 38, FIG. 3, comprising a control member 48, simultaneously controlling a movement of approaching or moving away of electrodes by rotation in one direction or in opposite direction (see page 9, line 11 to page 10, line 11).

Other devices for advancing the electrodes have been described in documents FR-86 01380 or FR-86 06318, filed by the present applicants.

In the last document FR-86 06318, a device for advancing an electrode 108 or an electrode-carrying element 109 is described in which the arrival of electric current from the current source is carried out by a conductor 202 terminating to an electrically conductive element 204 in permanent sliding contact on the electrode-carrying element 109 and also electrically conductive, to provide a sliding electrical contact.

However, the present inventors have observed that such an electrical contact design complicates the assembly and disassembly of the electrodes or of the electrode-holder elements with their electrodes.

In addition, due to the sliding electrical contact, there could be a surface oxidation of the respective surfaces in sliding contact resulting in a decrease in the electrical conductivity, all the more so since this sliding contact was made near the head of the electrodes. which can be soiled, either by a lubricant used, or by liquid coming from the cavity filled with liquid, in which bathes at least partly the electrode, and this due to the displacement of the electrode.

Thus, the invention aims to solve a new technical problem consisting in the provision of a device ensuring improved electrical contact between an electrical conductor for supplying electrical current and an electrode or an electrode-carrying element that is electrically conductive in design. simple allowing easy assembly and disassembly of the electrodes or the electrode holder elements with their electrodes.

Another object of the present invention is to solve a new technical problem consisting in the provision of a device ensuring an improved electrical contact making a automatic cleaning of surfaces in electrical contact, thus resulting in practically perfect maintenance of electrical conductivity at the level of electrical contact.

The present invention also aims to solve a new technical problem consisting in the supply of a solution making it possible to avoid soiling of the electrical contact by a lubricant, or a liquid coming from the cavity filled with liquid in which bathes at least in part of the electrode and / or the electrode holder element.

Preferably, these new technical problems must be resolved so as to allow the use in any advancement device of an electrode or of an electrode-holder element and in particular in a device of advancement of electrodes or elements electrode holder forming part of a device generating pulses of high frequency, or shock waves, thereby making it possible to increase the efficiency of destruction of targets, such as lithiasis or living tissue.

All these new technical problems are solved for the first time by the present invention in a satisfactory manner, by providing a solution of relatively low cost largely offset by a significant gain in productivity, a gain in electrical conductivity during multiple uses of the electrodes and finally by an increase in the efficiency of destruction of targets in the case of use in devices intended to destroy targets by generation of discharge or electric arc.

Thus, the present invention provides, according to a first aspect, a device ensuring improved electrical contact between an electrical conductor for supplying electrical current, forming part of a connector for supplying electrical current, and an electrode, or a carrier element. electrically conductive electrode, mounted displaceable in an insulating support, by the presence of permanent electrical contacting means interposed between said electrical conductor and said electrode or the electrode-carrying element, characterized in that said means permanent electrical contact comprise a member forming a fixed position nut, made of an electrically conductive material, having an axial through hole through which the electrode or the electrode holder element passes.

Preferably, the nut-forming element is fixed to an electrically conductive connection plug, by any suitable advantageously electrically conductive means, such as a screw, said connection plug being embedded in the mass of the insulating support and forming part of the connection technology. power supply of the electrode or of the electrode-holder element.

According to another particularly advantageous characteristic of the invention, the above-mentioned axial orifice is threaded and the electrode or the electrode-holder element comprises a corresponding thread on an appropriate zone covering the extreme positions of displacement of the electrode or the electrode holder. Preferably, this thread is continuous so as to allow electrical contact over a larger surface.

According to another particularly advantageous characteristic of the invention, the above-mentioned nut element is formed by two complementary half-discs.

Advantageously, each half-disc comprises at least one slot, and preferably two diametrically opposite slots, arranged in the same axial cutting plane, so as to be in coincidence, preferably two by two, when the two half meet. - discs; at least one half-disc, and preferably both, comprises a centering strip of dimension corresponding to two coincident slots, a part of the strip is fixed in a slot of the half-disc carrying the strip and the remaining part of the strip is inserted into the slot of the other half disc.

Preferably, each half-disc comprises a strip and the two strips are diametrically opposite and fixed symmetrically with respect to the center of the nut-forming element.

According to a particular embodiment, the strip has the shape of a truncated disc sector.

According to another particularly advantageous characteristic of the invention, the nut-forming element externally comprises an annular housing in which is disposed an elastic return means tending to keep the two half-discs in contact with each other, such that 'a coil spring mounted under tension.

It is thus understood that one obtains all the technical advantages previously stated, in a non-obvious and completely unexpected manner, namely: a significant gain in productivity thanks to the ease of assembly and disassembly of the electrodes or of the electrode-holder elements. with their electrodes; a significant gain in electrical conductivity during operation, thanks to the maintenance of the initial electrical conductivity; in addition, automatic cleaning of the electrical contact thanks in particular to the thread of the nut-forming element cooperating with the thread of the electrode or of the electrode-holder element, and finally by avoiding soiling of the electrical contact with a lubricant or liquid coming from the cavity filled with liquid in which at least partially bathes the electrode and / or the electrode-carrying element by virtue of the making of the electrical contact at the rear end of the electrode or of the carrying-element electrode well beyond the device for controlling the advancement of the electrodes or the electrode holder elements.

It is thus conceivable that the invention could constitute a determining technological contribution thus allowing its use in any device for advancing an electrode or an electrode-holder element, and in particular in a advancement device forming part of a apparatus for generating high frequency pulses or shock waves, this use also forming an integral part of the invention.

Finally, the invention relates, according to another aspect, to an apparatus for generating pulses of high frequency, or shock waves comprising a device for concentrating these pulses on a target focal point, which may preferably be a truncated ellipsoidal reflector, usually comprising two electrodes arranged to generate a discharge or electric arc between them generating said pulses or shock waves, at least one of the two electrodes being mounted displaceable by means of an electrode advancement device, characterized in that it comprises a device ensuring contact electric as previously defined.

• - la figure 1 est une vue en perspective d'un mode de réalisation actuellement préféré d'un dispositif assurant un contact électrique amélioré selon l'invention, utilisé dans un dispositif d'avancement d'électrode lui-même incorporé dans un appareil de génération d'impulsions, ou d'ondes de choc dont on a représenté schématiquement la paroi de la cavité dans laquelle sont générées lesdites impulsions ou ondes de choc ; et
• - la figure 2 est une vue éclatée de l'élément formant écrou constituant une des pièces essentielles du dispositif selon la présente invention.

Other objects, characteristics and advantages of the invention will appear more clearly in the light of the explanatory description which will follow, given with reference to the appended drawings representing a currently preferred embodiment of the device ensuring an improved electrical contact according to the invention , in its preferred use in a device for generating pulses of high frequency, or shock waves, given simply by way of illustration and which therefore cannot in any way limit the scope of the invention. In the drawings:

• - Figure 1 is a perspective view of a currently preferred embodiment of a device ensuring an improved electrical contact according to the invention, used in an electrode advancement device itself incorporated in a generation device pulses, or shock waves, the wall of the cavity in which said pulses or shock waves have been schematically represented; and
• - Figure 2 is an exploded view of the nut member constituting one of the essential parts of the device according to the present invention.

With reference to FIGS. 1 and 2, a device ensuring improved electrical contact according to the present invention is represented by the general reference number 10. This device 10 provides electrical contact between an electrical conductor represented by the general reference number 12, d electric current supply forming part of an electrical current supply connection, and an electrode 14 or more precisely here an electrode-carrying element 16 carrying the actual electrode 14.

This device 10 ensuring an electrical contact, according to the invention, is shown here used with a device 18 advancement of the electrode 14 or more precisely here of the electrode-carrying element 16.

This device for advancing the electrodes is for example that described and represented in patent application FR-86.06318 filed by the applicants and which comprises a wheel 20 provided with two reverse teeth 22, 24 controlled by two control means 28, 30 arranged in the plane of the teeth and on either side of the wheel 20. These control means 28, 30 here comprise pistons 32, 34 for example controlled hydraulically or pneumatically by being incorporated in the corresponding piston bodies. For a more precise description, reference should be made to this earlier request from the applicants incorporated here by reference.

The two teeth 22, 24 can be spaced so as to leave a surface area 20a between the teeth 22, 24 having position locking notches 40 cooperating with a locking pawl 42. These locking notches can simply be constituted by recesses clearly visible in Figure 1.

It will be observed that the electrode-carrying element 16 is integral in rotation but displaceable in translation relative to the wheel 20 which has for this purpose a coaxial orifice 44 passing through of polygonal section, here square, cooperating with a corresponding square part of the element electrode holder 16.

According to the invention, the device 10 ensuring electrical contact comprises an element 50 forming a fixed position nut, made of electrically conductive material, constituting means of permanent electrical contact between the electrical conductor 12 and the electrode-carrying element 16. This nut-forming element 50 has an axial orifice 52 passing through it, through which the electrode passes, more precisely here the electrode-carrying element 16 and it is also observed that the electrical conductor 12 must transmit the electric current to the nut-forming element. 50.

Advantageously, the nut-forming element 50 is fixed to an electrically conductive connection plug 54, by any suitable advantageously electrically conductive means, such as than a screw 56. This connection plug 54 is embedded in the mass of the insulating support in which the electrode-carrying element 16 and the control device 18 are movably mounted. This connection plug 54 is naturally part of the connection supply of electric current to the electrode 14 or to the electrode-carrying element 16.

Preferably, the axial orifice 52 passing through is threaded with a thread 60 clearly visible in FIG. 2, and the electrode or the electrode holder element comprises a corresponding thread, not visible, on a suitable zone covering the extreme positions. of movement of the electrode 14 or of the electrode-carrying element 16. Each thread is preferably made continuous to allow electrical contact over a larger surface, but this thread could be discontinuous, such discontinuous threads being well known in the art. skilled in the art.

According to another particularly advantageous characteristic of the invention, the nut element 50 is formed by two complementary half-discs 50a, 50b.

Preferably, each half-disc 50a, 50b comprises at least one slot 60, 64, and preferably two diametrically opposite slots 60, 62; 64, 66. These slots are arranged in the same axial cutting plane as is understandable from the consideration of Figure 2, so as to be in coincidence, preferably two by two (for example 60 and 64; and 62 and 66), when the two half-discs 50a and 50b are combined. At least half a disc, and preferably both, as shown, comprises a centering strip 68, 70 of dimension corresponding to two coincident slots. A part 68a, or 70a of the strip 68 or 70 is fixed in a slot of the half-disc carrying the strip by any fixing means, for example a pin passing through an orifice 72 or 74 provided in the half-discs 50a and 50b and coming into an orifice 76, 78 provided in the strips 68 and 70. It is understood that the remaining part of the strip is inserted into the slot 64 for the strip 68, or the slot 62 for the strip 70 of the other half disc 50a or 50b.

Preferably, and as shown, the two strips 68, 70 are arranged diametrically opposite and fixed symmetrically with respect to the center of the nut-forming element, which makes it possible to simplify the joining of the two half-discs 50a and 50b. Advantageously, the strip 68 or 70 has the shape of a truncated sector of a disc as is clearly visible in FIG. 2.

According to another advantageous characteristic of the invention, the nut element 50 externally comprises an annular housing 80 in which is disposed an elastic return means tending to keep the two half-discs 50a and 50b in contact with one another. other, such as a coil spring mounted under tension. It is thus possible to take a helical spring of length less than the circumference of the annular housing 80 and the ends of which are tucked into each other by a few turns to form an annular helical spring which is then stretched to be placed in the annular housing. 80 where it then exerts a compression force on the two half-discs 50a and 50b one against the other.

It can also be seen in FIG. 2 that one of the two half-discs 50a or 50b, here 50b, comprises a notch 82 forming a housing for fixing the connection plug 54 which is followed by an orifice 84 allowing the passage of the means of attachment 56 such as a screw from the other side.

Naturally, the nut element 50 is made of an electrically conductive material, and therefore preferably of copper although other electrically conductive materials can be used.

As has been said previously, this device 10 ensuring an electrical contact, according to the invention, is preferably used in combination with a device 18 for advancing an electrode 14 or an electrode-carrying element 16. The electrode 14, more precisely the electrode holder element 16 is shown in FIG. 1 mounted on the wall 90 of a device for generating and concentrating pulses on a target focal point, which is preferably a truncated ellipsoidal reflector of the type describes by Rieber in US Patent 2,559,227. Thus, such a truncated ellipsoidal reflector usually comprises two advantageously identical electrodes 14 arranged to generate a discharge or electric arc between them. In general, said pulses are generated at the internal focal point of the ellipsoidal reflector, so that the electrodes are arranged concurrent with this internal focal point to allow these pulses to be concentrated on the other focal point of the ellipsoid where the target to be destroyed will be located. For more precise operation of such devices, see the previously stated documents.

The ellipsoidal reflector, part of the wall 90 of which is seen to be electrically conductive, it is necessary to isolate the electrode 14 and the electrode-carrying element 16 from the wall 90 by interposing an insulating support 94 in the internal part to the cavity 92 as clearly represented in FIG. 1, which is of substantially tubular shape ending in a conical front part 96 towards the tip of the electrode 14 so as to allow the electrode 14 to be completely isolated as close as possible to its end 14a.

Since the cavity 92 is filled with a liquid, advantageously water, it is naturally necessary to provide seals 98, 100, 102, 104, 106, 108.

It is thus understood that it follows from the above that the element 50 forming an electrical contact nut is in a fixed position thanks to the connection plug 54 which is embedded, and therefore itself in a fixed position, in the surrounding insulating support. the whole device. Thus, the actuation of the control device 18 causes rotation of the wheel 20, while the nut element 50, of fixed position, with its thread 60 cooperating with a corresponding thread forming the screw of the electrode holder element 16 , leads to a movement of advancement or withdrawal of the electrode-carrying element 16 as a function of the direction of rotation given by the advancement device 18 depending on whether one or the other of the pistons 32 or 34 is actuated.

An electric current is permanently ensured thanks to the clamping effect of the elastic return element 81, such as a helical spring. Furthermore, an automatic cleaning of the electrical contact takes place thanks to the presence of the thread of the nut element 50 cooperating with the thread of the electrode holder element, thereby eliminating the oxidized particles or any disturbing particle, such as dust or whatever.

On the other hand, due to the fact that the nut element 50, constituting an electrical contact element, is mounted at the rear part of the electrode or electrode holder element 16, as far as possible from the front end 14a of the electrode 14, makes it possible to avoid soiling of the electrical contact by a lubricant or a liquid coming from the cavity 92. It will be observed here that, in addition, the control device 18 is interposed between the nut-forming element contact 50 and electrode 14.

In addition, thanks to the production of the contact nut element 50 in two half-discs 50a, 50b tightened by a tightening means formed by the elastic return means 81, a flexible tightening is obtained which adapts perfectly to the differences possible diameters of the electrode-carrying element 16, and avoiding any blocking of the electrode-carrying element 16 in the nut-forming element 50.

In addition, thanks to this structure of the nut-forming element 50, it results in ease of assembly and disassembly of the electrodes or more precisely of the electrode-holder elements 16 with their electrodes 14, thereby improving productivity.

Thus, one obtains all the determining technical advantages previously stated.

On the other hand, a completely unexpected and not obvious additional advantage of the invention resides in the fact that the element 50 forming an electrical contact nut being of fixed position by being fixed in the insulating support by means of the connection plug 54 embedded in the mass of the insulating support, and comprising a thread 60, the nut-forming element 50 is thus integrated into the entire system for advancing the electrode 14 or the electrode holder element 16 thus constituting the part forming a fixed position nut, necessary to lead to a lateral displacement (advancement or withdrawal) of the electrode holder element under the effect of the rotation of the wheel 20 by one or other of the pistons 32 or 34. Thus, the thread 60 of the element 50 forming an electrical contact nut also fulfills the same function as the thread 170 forming the nut of the insulating support 112b, FIGS. 1 and 2 of document FR-86 06318.

Naturally, the invention includes all the means constituting technical equivalents of the means described as well as their various combinations.

Claims (11)

1. Device ensuring improved electrical contact between an electrical conductor (12) for supplying electrical current forming part of an electrical power supply connector, and an electrode (14), or an electrode-carrying element (16) electrically conductive, mounted displaceable in an insulating support, by the presence of means (10) for permanent electrical contact interposed between said electrical conductor (12) and said electrode (14) or the electrode holder element (16), characterized in that said permanent electrical contacting means (10) comprise a nut element (50) of fixed position, made of electrically conductive material, comprising an axial orifice (52) passing through which passes the electrode (14) or the 'electrode holder element (16). 2. Device according to claim 1, characterized in that the nut-forming element (50) is fixed to an electrically conductive connection plug (12), by any suitable advantageously electrically conductive means, such as a screw, said connection plug ( 54) being embedded in the mass of the insulating support and forming part of the electrical current supply connection for the electrode (14) or the electrode-carrying element (16). 3. Device according to claim 1 or 2, characterized in that the axial orifice (52) passing through is threaded (at 60) and the electrode (14) or the electrode holder element (16) comprises a corresponding thread on an appropriate zone covering the extreme positions of displacement of the electrode (14) or of the electrode-carrying element (16). 4. Device according to one of claims 1 to 3, characterized in that the nut-forming element (50) mentioned above is formed by two complementary half-discs (50a, 50b). 5. Device according to claim 4, characterized in that each half-disc (50a, 50b) comprises at least one slot (60, 66), and preferably two diametrically opposite slots (60, 62; 64, 66), arranged in the same axial section plane, so as to find themselves in coincidence, preferably two by two, when the two half-discs (50a, 50b) meet; at least a half-disc, and preferably both, comprises a centering strip (68, 70) of dimension corresponding to two coincident slots (60, 64; 62 and 66, respectively), a part (68a or 70a) of the strip (68 or 70) is fixed in a slot (60 or 66) of the half-disc (50a or 50b) carrying the strip and the remaining part of the strip (68 or 70) is inserted in the slot (64 or 62 ) on the other half-disc. 6. Device according to claim 5, characterized in that it comprises two centering strips (68 and 70) diametrically opposite and fixed symmetrically relative to the center of the nut-forming element (50). 7. Device according to claim 5 or 6, characterized in that the centering strip (68 or 70) has the shape of a truncated disk sector. 8. Device according to any one of claims 1 to 7, characterized in that the nut-forming element (50) externally comprises an annular housing (80) in which is disposed an elastic return means (81) tending to tighten the two half-discs (50a and 50b) in contact with one another, such as a helical spring mounted under tension. 9. Device according to one of claims 1 to 8, in which the electrode or the electrode-carrying element is controlled to move by a displacement system, characterized in that the nut-forming element (50) is integrated into said system of displacement. 10. Use of the device as defined in any one of claims 1 to 9, in any device for advancing an electrode (14) or an electrode-holder element (16), in particular in a device for advancement forming part of a device generating pulses of high frequency, or shock waves. 11. High frequency pulse generator or shock waves, comprising a device for concentrating these pulses on a target focus, possibly being a truncated ellipsoidal reflector, usually comprising two electrodes arranged to generate a discharge or electric arc between them generating said pulses or shock waves, at least one of the two electrodes being mounted displaceable by means of a device (18) for advancing the electrode (14) or of an element (16) carrying electorde, characterized in that it comprises a device (10) ensuring an electrical contact as defined according to any one of claims 1 to 9.

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