Coupling system for surgical instrument

Abstract

The present invention relates to a coupling system (1) between a robotic arm (2) and a surgical or dental instrument (3), the coupling system (1) being formed by a single interconnecting piece (10) comprising on the one hand a kinematic coupling portion (11) intended for coupling with the robotic arm (2) and on the other hand a coupling cap (12) for coupling with the surgical or dental instrument (3) along a longitudinal coupling axis (B-B).

Description

[0001] Coupling system for surgical instruments

[0002] Technical field of the invention

[0003] The present invention relates to the field of surgical and dental instruments, and more particularly to the use of such instruments assisted by robots.

[0004] State of the art

[0005] In the field of machine tools, kinematic coupling methods, known as "kinematic mounts," are known to provide very good positioning repeatability by ensuring the locking of 6 degrees of freedom (3 translational directions and three rotational degrees of freedom, also known as Maxwell's criterion). An example of this type of solution is described in patent document US6460436B1.

[0006] These mounting systems are also used in combination with dental appliances, as described in patent document US2005060868A1, which refers to an application for the fabrication of dental prostheses, and in patent document US2022280265A1, which uses a mounting or coupling satisfying the above Maxwell criterion between a dental model and a thermoformed dental aligner.

[0007] The robust and repeatable connection between robotic arms, platforms, and the connection of robotic arms to surgical instruments is crucial for the performance of automated and semi-automated surgical equipment. However, as demonstrated in the solutions described in patent documents US11612445B2 and EP4205689A1, it is often necessary to simultaneously maintain a sterility barrier between components or devices that can and must be reprocessed (cleaned and disinfected) and sterilized, as these components come into contact with the patient and are therefore classified as critical or semi-critical according to ISO 17664-1:2021. Conversely, components or surfaces that cannot be subjected to such an aggressive procedure can simply be cleaned, provided they do not come into contact with the patient, and are therefore classified as non-critical according to ISO 17664-2:2021.

[0008] In general, fully kinematic coupling methods satisfying the Maxwell criterion used in surgery or dentistry require significant bulk and the presence of several intermediate fixing parts or components to ensure sufficient sterility. The solution described in document KR102019984B1, for example, shows a fixing system for a particularly bulky dental or surgical contra-angle handpiece that completely surrounds the 'motor' part (rear section) of the device.

[0009] The drawbacks observed in prior art solutions can be summarized as follows:

[0010] - the procedure for assembling and disassembling the instruments or devices of the robotic arms is often long and difficult, which makes it complex to carry out the cleaning, disinfection and sterilization steps;

[0011] - the assembly often requires small components for fixing which can be easily lost during reprocessing operations of the surgical tool;

[0012] - In general, it is necessary to add sterile single-use sheets to effectively isolate (i.e., hermetically seal) non-critical components or devices, such as the robotic arm itself, when using surgical tools;

[0013] - The connection to the motor requires a significant number of components, which is detrimental to the system's accuracy and repeatability, particularly regarding the spatial position of the cutting tool relative to the sensor-equipped platform. Under these conditions, a recalibration step is unavoidable when the system is disassembled, typically during reprocessing procedures. Furthermore, kinematic mounting systems described in the literature (i.e., the "kinematic mount" type described above) generally employ mating surfaces that are either virtually flat or completely surround the medical component / device, especially the handpiece. These types of constraints make the entire system less ergonomic for the surgeon or dentist, hindering their manual access to the tools.This has the effect of severely limiting the application of these coupling methods and devices to robotic surgical or dental instruments for surgeon / dentist assistance, i.e. to semi-automated systems where the robot helps the work of the surgeon / dentist but where ultimate control of the instrument is left to the surgeon / dentist.

[0014] The CN117814914A document describes a coupling device between a robotic arm and a surgical instrument for implantology, according to the prior art, disclosing an interconnection system composed of several parts, including a coupling ring inserted at the rear of the surgical tool. The kinematic coupling portion for the robot is connected to the coupling ring via a central piece, which is itself connected to the ring.

[0015] Document EP4364686 describes a coupling system that, unlike the previous document, does not involve a surgical instrument and a robot, but rather a tool body and a sensor, via a coupling ring and a spacer. Therefore, there are no constraints on force or motion transmission from the sensor, as might exist from a robotic arm, and consequently, no kinematic coupling is disclosed in this document, since the sensor connected to the rear of the robot is entirely passive and simply an auxiliary instrument to the tool. Furthermore, the support formed by a clamp and the clip-on retention method would be completely unsuitable for coupling to a robotic arm.

[0016] The document US20130175769 concerns a tool holder intended for machine tools and a priori more particularly for drills with diameter adapters; the lessons of this document focus on tool alignment properties and incidentally discuss the interest of different materials in order to minimize costs.

[0017] The document DE4446985 relates to a handpiece that can undergo surface hardening treatment by thermal / chemical treatment.

[0018] There is therefore a need for solutions free from the known limitations of the prior art.

[0019] Summary of the invention

[0020] One aim of the present invention is to provide a simplified and high-precision coupling solution between a robotic arm and a surgical instrument such as a dental handpiece.

[0021] Another objective of the present invention is to provide a solution whose ergonomics are maximized for the dental surgeon, without however deteriorating the quality and reliability of the kinematic coupling.

[0022] Yet another objective of the present invention is to simplify the sterilization process for surgical devices assisted by robotic arms.

[0023] These goals are achieved through the features of the main claim, and in particular through a coupling system between a robotic arm and a surgical or dental instrument, the coupling system being formed by a single interconnecting piece comprising on the one hand a kinematic coupling portion intended for coupling with the robotic arm and on the other hand a coupling cap for coupling with the surgical or dental instrument along a longitudinal coupling axis.

[0024] One advantage of the proposed solution is that it allows for direct coupling, via a single component—the interconnecting piece—between the robotic arm and the surgical or dental instrument. This eliminates the need for numerous bulky intermediate parts. Furthermore, the reduced number of components minimizes the accumulation of manufacturing inaccuracies and play, thus further improving coupling accuracy regardless of the rigid fastening method used (screwing, pressing, bonding, or welding).

[0025] Another advantage of the proposed solution is that it ensures the ergonomics of the connection to the surgical or dental instrument. This connection takes the form of a coupling cap designed to partially enclose the instrument around its longitudinal axis, which typically corresponds to the coupling nose of the micromotor, further minimizing its overall size. This shape for the coupling element also provides the added benefit of creating a simple and effective sterilization barrier for the robotic arm.

[0026] According to a preferred embodiment of the invention, the coupling between the coupling cap and said surgical or dental instrument is achieved by screwing.

[0027] This mounting system is particularly advantageous for right-handed handpieces, which do not require precise alignment around the motor's axis of rotation. It allows the use of a mounting system similar to that of the "classic" end caps that form the outer casing of this type of handpiece. Consequently, the coupling end cap, which is attached to the handpiece frame, is completely seamless, as if it were a simple replacement end cap. No modifications are therefore necessary on the right-handed side, which is also a significant advantage in terms of compatibility and market acceptance of this solution.

[0028] According to yet another preferred embodiment of the invention, the kinematic coupling portion of the interconnecting piece is arranged to be located at the rear of the surgical or dental instrument in the mounted position.

[0029] Such a configuration makes it possible to further reduce the risk of contamination of the robotic arm and the interface areas between the robotic arm and the surgical or dental instrument, because the most contaminated area is located at the front at the level of the instrument head which is in direct contact with the patient's tissues.

[0030] According to another preferred embodiment of the invention, the kinematic coupling portion and the coupling cap of the interconnecting piece are made in a single piece.

[0031] This configuration ensures rigid and optimal guidance or alignment with the robotic arm, particularly when the surgical or dental instrument consists of a micromotor assembled to a handpiece. In such a case, there is no need for recalibration or position adjustment during installation. The motor axis and the handpiece's drive shaft are then intrinsically aligned and parallel to the connection plane between the handpiece and the robotic arm, simplifying the navigation and positioning process for the robotic arm.

[0032] According to yet another preferred embodiment of the invention, the kinematic coupling portion and the coupling cap of the interconnecting part are made of two different materials.

[0033] In this way, it is possible to choose an ultra-rigid material for the kinematic transmission of the robotic arm's movements at the rear, at the kinematic coupling portion, but, conversely, a slightly less rigid material at the front, at the coupling cap, in relation to the surgical or dental instrument, in order to better absorb the vibrations experienced during the operation. According to an even more preferred embodiment, the interconnecting part of the coupling system consists of a coupling cap made of a material with a hardness between 100 and 400 Vickers, and a kinematic coupling portion made of a material with a surface hardness between 450 and 900 Vickers.

[0034] In such a configuration, where materials are separated according to the type of coupling, each functional part of the coupling system's interconnecting component can be optimized. Thus, the coupling cap for the surgical or dental handpiece can be made of a material that dampens vibrations, has good corrosion resistance, and is easily machinable and engravable, while the material chosen for the kinematic coupling portion with the robotic arm can be made of a wear-resistant and tough material, so as to guarantee the most faithful and durable transmission of the robotic arm's movement.

[0035] According to yet another preferred embodiment of the invention, the coupling cap of the interconnecting piece comprises a concave surface intended to at least partially receive a micromotor for a dental handpiece, and a convex surface at least partially enveloping the micromotor.

[0036] In such a configuration where the coupling system is more specifically intended for a dental handpiece used as a surgical instrument, particularly in the context of implantology, the bulk is minimized and simultaneously ensures the effective creation of a sterile barrier.

[0037] According to an even more preferred embodiment of the invention, the concave surface of the coupling cap of the interconnecting part constitutes an internal bearing surface designed to conform to the external shape of the micromotor. In such a configuration, the coupling cap is made to adhere as closely as possible to the surface of the external cap of the micromotor, reducing contamination between the two surfaces, and ensures good guidance and limits the risk of excessive vibrations, while ensuring the smallest possible overall size.

[0038] According to an even more preferred embodiment for implementing the invention, the cross-section of a front edge of the coupling cap extends over an angle of at least 150 degrees.

[0039] Such a configuration optimizes the grip of the micro-motor by the coupling cap with the handpiece, thus minimizing the risk that, due to excessive vibrations, the motor could suddenly disconnect and possibly fall (considering that the handpiece is held manually by the user and by the robotic arm, while the motor is held only via the connection with the handpiece according to a predefined standard - ISO 3964 - requiring only a relatively low minimum holding force, on the order of 30 N); moreover, the coupling cap provides additional guidance in case of significant vibrations.

[0040] According to an even more preferred embodiment for the implementation of the invention, the cross-section of the front edge of the coupling cap extends over an angle of up to 210 degrees.

[0041] This configuration further maximizes guidance and vibration damping properties by wrapping the micromotor around more than half its outer circumference, without significant additional manufacturing costs. Furthermore, it allows the practitioner to maintain visual contact with the connection point between the micromotor and the dental or surgical instrument, thus preventing the risk of unpredictable malfunctions caused by partial disconnection between the two components.

[0042] According to yet another preferred embodiment for implementing the coupling system according to the invention, the kinematic coupling portion comprises a tapped through hole extending along a transverse coupling axis having a first direction vector, the longitudinal coupling axis having a second direction vector and the first and second direction vectors being distinct.

[0043] In such a configuration, the screw coupling to the robot via the tapped hole allows 5 degrees of freedom to be fixed at once, which is particularly advantageous in terms of ease of assembly; moreover, the fact that the coupling with the robotic arm is carried out along a transverse coupling axis distinct from that used for the coupling with the surgical or dental instrument allows for a gain in compactness through a saving of space at the rear of the handpiece or thickness of the coupling cap, and also allows for a significant reduction in vibrations around this latter longitudinal axis which is also the axis of rotation of the micromotor.

[0044] According to yet another more preferred embodiment of the invention, the transverse coupling axis of the tapped hole is perpendicular to the longitudinal coupling axis, and a series of coupling grooves is further provided in a plane perpendicular to the tapped through hole, the series of coupling grooves being formed by a first coupling groove, a second coupling groove and a third coupling groove oriented mutually at 120° to each other symmetrically with respect to the tapped through hole.

[0045] This configuration allows for particularly simple kinematic coupling to the robotic arm. The tapped hole secures five degrees of freedom at once, while the coupling groove secures the remaining rotational degree of freedom in the plane perpendicular to the tapped hole and perpendicular to the longitudinal coupling axis, which corresponds to that of the micromotor's coupling nose. In this way, the assembly / disassembly operation is particularly simple, quick, and repeatable, and vibrations along the longitudinal coupling axis are minimized. Furthermore, the specific arrangement of the grooves allows for very simple fixing of the six translational and rotational degrees of freedom between the robotic arm and the handpiece, facilitating the assembly process by significantly reducing the adjustment of the last degree of freedom using the multiple symmetrically arranged grooves.This fastening system ensures highly precise and long-term locking of the five remaining degrees of freedom, as it eliminates the effect of play between the threads, provides additional rigidity, and offers significant wear resistance. Furthermore, this configuration simultaneously minimizes difficult-to-clean hollow areas, such as through holes. For example, replacing the three grooves with two additional through holes would result in cleaning procedures that are three times more complex than those required for a single through hole.

[0046] According to an even more advantageous version, the kinematic coupling portion and the coupling cap of said interconnecting part are welded together, the weld line being in correspondence with the peripheral edge of the kinematic coupling portion and describing an angle greater than or equal to 240°, with respect to the axis of symmetry of the tapped through hole.

[0047] Such a configuration makes it possible to increase the strength of the interconnecting part with respect to the main mechanical forces which are oriented in the direction of the coupling grooves, minimizing the risk of separation between the coupling cap and the kinematic coupling portion.

[0048] According to an even more preferred embodiment for the implementation of the invention, the through hole of the coupling system is formed by a modular part fixed to a through opening of the portion of the kinematic coupling by means of crimping, gluing or welding.

[0049] This particularly advantageous configuration allows for easier threading in a workpiece whose size and shape—typically of revolution, and preferably cylindrical—are ideally suited for such machining, rather than performing this operation on a portion of the kinematic coupling or even the entire interconnecting part. Furthermore, this modular construction for the part containing the tapped hole facilitates assembly during production and allows for the selection of an optimal material that can be separated from the kinematic coupling portions and the coupling cap.

[0050] According to another preferred embodiment, the coupling system is characterized in that the connection interface between the micromotor and the surgical or dental instrument is in a substantially median position between the front end of the coupling cap and the tapped through hole.

[0051] In this way, the surgical or dental instrument is held particularly effectively, preventing any torsional stress around its longitudinal axis. The practitioner's precision and comfort are thus maximized.

[0052] According to yet another preferred embodiment of the coupling system according to the invention, wherein the surgical or dental instrument is a contra-angle, and the coupling cap is fixed to said contra-angle using a fastening system with integrated keying.

[0053] In this configuration, the keying system allows for precise control of the contra-angle's angular orientation relative to the micromotor's axis of rotation, which is unnecessary for a right-handed instrument. The contra-angle can then be oriented along a vertical plane perpendicular to the axis of the tapped hole; in other words, the contra-angle's sagittal cutting plane corresponds to this vertical plane perpendicular to the tapped hole of the kinematic coupling portion. This simplifies mounting the contra-angle to the interconnecting piece and simultaneously ensures a particularly ergonomic orientation of the contra-angle once it is coupled to the robotic arm via the tapped hole.This orientation of the contra-angle, which, according to an even more preferential embodiment, corresponds to a plane parallel to that defined by the 3 coupling grooves used for coupling to the robotic arm, also minimizes the bending of the interconnecting piece, which is subjected to the forces applied to the cutting tool.

[0054] Brief description of the drawings

[0055] The present invention will be better understood upon reading the following description, given by way of non-limiting examples for the implementation of the invention and made with reference to the drawings in which:

[0056] - Figure 1 is a three-dimensional view of an interconnecting piece used as a coupling system according to the invention for a surgical and dental instrument, when the latter consists of a straight dental handpiece;

[0057] - Figures 2A and 2B are three-dimensional views respectively of the inside and outside of the coupling cap of the interconnecting part of Figure 1, when it is attached to the right-hand part;

[0058] - Figure 3 shows a three-dimensional view of the interconnecting piece mounted to a right-handed piece according to the preferred embodiment illustrated by the previous figures, also illustrating the micromotor intended to be mounted at the rear of the handpiece;

[0059] - Figure 4 is an exploded three-dimensional view of an interconnecting part used as a coupling system according to the invention for a surgical or dental instrument, when the latter consists of a contra-angle, highlighting the fixing system with integrated keying and a modular coupling part for kinematic coupling with the robotic arm;

[0060] Figures 5A and 5B are three-dimensional views, respectively, of the interior and exterior of the coupling cap of the interconnecting piece in Figure 4, when it is fixed to the contra-angle handpiece. Detailed description of the invention

[0061] In the following description, preferred embodiments for the realization of the invention will be described where the surgical or dental instrument 3 is respectively formed by a straight dental handpiece (as in Figures 1, 2A-2B, and 3) and respectively a contra-angle (as in Figures 4 and 5A-5B); however, those skilled in the art will understand that the invention potentially applies to other types of surgical or dental instruments.

[0062] Figure 1 shows how the coupling system 1 between a robotic arm 2, located at the rear of a surgical or dental instrument 3 constituted here by a straight handpiece 32, so as to form and provide the most effective sanitary barrier possible with respect to the robotic arm 2. The latter not being part of the device which the invention seeks to protect, it is only materialized by this reference (2) towards which a dashed arrow points to indicate its relative positioning with respect to the other parts of the coupling system 1.

[0063] According to the invention, we seek not only to provide an effective coupling system for forming a sanitary barrier between the surgical or dental instrument 3 and the robotic arm 2, but also to gain simplicity in terms of the number of parts required for the coupling, while simultaneously ensuring the rigidity of the coupling and therefore the efficiency and reliability of the kinematic transmission of the movements of the robotic arm 2.

[0064] The coupling system 1 thus consists of a single interconnecting part 10, ensuring direct coupling between the robotic arm 2 and the surgical or dental instrument 3, here constituted by the right-handed part 32, without requiring intermediate parts that are prone to play or drift in the kinematic transmission of movements. The structurally simple interconnecting part 10 connects two functional parts: a kinematic coupling portion 11 for coupling with the robotic arm 2 and a coupling cap 12 for coupling with the surgical or dental instrument 3 along a longitudinal coupling axis (BB), which here corresponds to that of the right-handed part 32.

[0065] As can be seen in the exploded view of Figure 1, the handpiece 32, or more precisely the body of this right-handed handpiece 32, is shown on the left with the irrigation channel 35 near its head, into which a cutting tool is inserted. At the rear of this tool, a threaded portion 320 can be seen, which is designed to cooperate with a tapped portion 120 of the coupling cap 12 of the interconnecting part 10, located at the front of the latter. At the rear of the latter is positioned the kinematic coupling portion 11, intended for the robotic arm 2, with, in particular, a tapped hole 110 along an axis AA, intended for a standard screwing operation for coupling with robotic arms 2.

[0066] For mounting the coupling cap 12 to the right-handed piece 32 – or more generally any surgical or dental instrument 3 – various rigid fastening methods are possible, including pressing, bonding, and welding. The method illustrated in Figure 1, involving a screw system via the interaction of the threaded portion 320 at the rear of the right-handed piece 32 with the tapped portion 120 at the front of the coupling cap 12, is particularly advantageous for this type of part, which does not require precise orientation around the motor's axis of rotation. This is because it allows the use of the same fastening system as that used for "conventional" caps that form their usual outer casing. No adaptation is therefore necessary on the right-handed piece 32, with optimal coupling quality in terms of strength and durability, while requiring minimal assembly time.According to the preferred embodiment illustrated, the screwing is carried out along the longitudinal coupling axis (BB) along which the coupling cap (12) also extends.

[0067] Figure 1 also shows the concave 12A and convex 12B surfaces of the coupling cap 12, as well as a front edge 121 whose cross-section extends over a slightly more pronounced arc than at the rear towards the kinematic coupling portion 11. Such an arrangement aims to envelop the micromotor 4 - visible further on in Figure 3 - in order to maximize the guiding and anti-vibration properties.

[0068] In figures 2A and 2B, which will be described below and which relate to the same embodiment for the interconnecting part 10 as already described, we will not necessarily redescribe in detail all the characteristics whose references have already been explained in connection with figure 1.

[0069] Figures 2A and 2B show respectively the inside and outside of the coupling cap 12.

[0070] Figure 2A highlights the concave surface 12A of the coupling cap 12, designed to receive and enclose the micromotor 4 (visible in the following Figure 3) beyond the usual connection interface 34 for a handpiece such as the right-handed handpiece 32 shown, with an optimal shape match. As in the previous figure, the longitudinal coupling axis (BB) can be distinguished, and, at the rear of the interconnecting piece 10 and thus of the coupling cap 12, the kinematic coupling portion 11 for the robotic arm 2 can be seen. According to the embodiment illustrated in Figure 2A, the leading edge 121 of the coupling cap 12 extends over an angular sector of approximately 180°, in order to minimize the risk of unintentional detachment of the micromotor 4 in the event of excessive vibrations, while also providing additional guidance.To effectively perform this function, a wrap-around angle of at least 150°, but no more than 210°, is preferred. While an angle greater than 180° might be even better for guidance and protection as a sterilization barrier, too large a wrap-around angle could make assembly more difficult by requiring slight plastic deformations. Furthermore, an angle less than 210° always allows the user to maintain visual contact with the connection area between the micromotor and the dental or surgical instrument. This enables them to easily and immediately detect any gradual partial disconnection that could cause unforeseen malfunctions, ultimately allowing for proactive interruption of the clinical procedure before any risk to the patient can occur.

[0071] Figure 2B shows the exterior of the interconnecting part 10, and highlights the particular arrangement for the kinematic coupling portion 11 using a series of grooves 111 consisting of a first coupling groove 111A, a second coupling groove 111B and a third coupling groove 111C oriented mutually at 120° to each other symmetrically with respect to said tapped through hole 110 oriented perpendicular to them along the axis AA.

[0072] Such an arrangement makes it possible to fix the 6 degrees of freedom in translation and rotation between the robotic arm and the handpiece in a very simple way, facilitating the assembly process by considerably reducing the adjustment of the last degree of freedom using the plurality of grooves arranged symmetrically; the first five being fixed by means of screwing into the tapped hole and then the last being fixed by the series of grooves 111, here arranged in a totally symmetrical way in order to balance as much as possible the stress forces exerted on each of them, to come into mutual support with the robotic arm 2 (not illustrated in figure 2B).

[0073] According to a particularly advantageous embodiment, the kinematic coupling portion 11 and the coupling cap 12 of the interconnecting piece 10 are welded together, the weld line being in correspondence with the peripheral edge 112 of the kinematic coupling portion 11 and describing an angle greater than or equal to 240°, with respect to the axis of symmetry AA of the tapped through hole, as illustrated in Figure 2B.

[0074] This configuration increases the strength of the interconnecting part against the main mechanical forces, which are oriented in the direction of the coupling grooves, while minimizing the risk of separation between the coupling cap and the kinematic coupling portion. Figure 3 further illustrates a right-handed part 32 according to the embodiment shown in the preceding figures, in which the coupling cap 12 is still represented in three dimensions but from a viewpoint opposite to that of Figure 2A, with the interconnecting part 10 coupled to the right-handed part 32.

[0075] This figure also shows the micromotor 4 and its coupling nose 41, intended to be inserted into the connection interface 34 - illustrated previously in Figure 2A in the insertion direction - and it also highlights the advantageous median positioning of this connection area, whose longitudinal positioning corresponds precisely to that of the connection interface 34, halfway between the front end 1210 of the coupling cap 12 and the tapped through hole 110 of the kinematic coupling portion 11. The coupling nose 41 extends longitudinally along the longitudinal coupling axis (BB).

[0076] Such a configuration, compatible with a connection between the two drive shafts made in accordance with ISO 3694, is optimal for minimizing the torsional effects acting on the interconnecting part, while ensuring manual grip on the surgical or dental instrument. This is because the torsional forces increase significantly with the distance between the through hole and the connection area between the micromotor and the surgical or dental instrument. The approximately mid-position (M) between the front end 1210 of the coupling cap 12 and the tapped through hole 110, extending along a transverse coupling axis (AA), can be defined as corresponding to the midpoint of the distance separating these two elements, with a tolerance of approximately + / - 25%.For example, for a distance of 80 mm and a median positioning at 40 mm, the median position may be considered to be between 30 mm and 50 mm relative to the front end of the coupling cap 12 (or respectively of the tapped through hole 110) in order to obtain the advantageous technical effects in terms of optimal resistance to torsional effects.

[0077] Figure 3 also highlights the orientation of the direction vectors of the different coupling axes, namely the transverse coupling axis (AA) used for the robotic arm and the longitudinal coupling axis (BB) used for the surgical or dental instrument 3. The first direction vector A associated with the transverse coupling axis (AA) is distinct from the second direction vector B associated with the longitudinal coupling axis (BB); according to the preferred embodiment illustrated in this figure, the two direction vectors A and B are orthogonal; however, those skilled in the art will understand that such a configuration is not essential and that the fact that these direction vectors A, B are distinct is sufficient to improve the compactness of the coupling system and significantly reduce vibrations along the longitudinal coupling axis (BB), which is also the axis of rotation of the micromotor (4).

[0078] Figure 4 illustrates another preferred embodiment for the realization of the invention, employing not a right handpiece 32 as a surgical or dental instrument 3, but a contra-angle 31.

[0079] The main difference with the embodiment previously described with the help of figures 1, 2A-2B, 3 and 4 concerns the method of assembling the interconnecting part 10, i.e. the coupling cap 12, at the contra angle 31; however, those skilled in the art will understand that all the advantages mentioned previously in terms of guidance and kinematic transmission remain identical because the arrangement of the parts performing these functions - i.e. respectively the shapes of the coupling cap 12, in particular that of its internal concave surface 12A to envelop the micromotor, and that of the kinematic coupling portion 11 with the series of symmetrical grooves 111 (i.e. 111 A, 111 B, 111 C).

[0080] For all these reasons, and since most of the features referenced in this figure have already been described previously, they will not be explained again here and we will refer to the previous figures for more details.

[0081] One of the specific features of the coupling of the interconnecting piece in Figure 4 compared to that in Figure 1 is that it requires the use of a keying device for the assembly between the contra-angle 31 and the coupling cap 12. Keying systems are used to guarantee a precise angular position between two parts around an axis; in this case, it is a matter of ensuring that the contra-angle is oriented vertically, that is to say that its sagittal cutting plane corresponds to the plane in which the series of coupling grooves 111 with the robotic arm 2 are located (not referenced on this figure for the sake of readability).

[0082] Unlike the screwing via a threaded portion 120 at the front of the coupling cap 12 for the right handpiece 32 of figure 1, figure 4 uses a fixing system 6 with integrated keying, consisting of a first pin 61 with a first threaded screw tip 610, a second pin 62 with a second threaded screw tip 620, and finally, a third pin 63, positioned near the irrigation channel 35, and which can preferably be driven into the frame of the contra-angle 31, on which the optical fiber channel 36 can be seen, highlighted on the top.

[0083] The two pins, that is to say the first pin 61 and the second pin 62, are inserted through through holes in a standardized ring 340 which will define the connection interface 34 (visible in Figure 5A below), then screwed into the frame of the contra-angle, while the third pin 63 is inserted and then driven for example into a blind hole in the standardized ring 340 and then driven, via its other end, into a corresponding hole in the frame of the contra-angle (none of these holes on either side of the third pin 63 are visible in this figure).In this way, the angular positioning of the standardized ring 340 around the axis of rotation of the micromotor 4 (not visible in this figure either, but whose coupling with the contra-angle 32 would be done in a similar way to that with the right handpiece 31 illustrated in Figure 3 previously described) can be carried out very precisely, and the axial retention of the standardized ring vis-à-vis the handpiece is guaranteed by screwing the two other pins 61, 62.

[0084] Another specific feature of the coupling according to the preferred embodiment illustrated in Figure 4 concerns the kinematic coupling portion 11 at the rear of the coupling cap 1. Indeed, in this figure, it can be seen that the tapped through hole 110 is not made directly in the material of the kinematic coupling portion 11 itself, but in a modular coupling part 5, preferably consisting of a part of revolution, and here, a cylinder. Such a modular part 5 is then inserted into a through opening 113 of the kinematic coupling portion 11, which, according to this embodiment, is also designed as a separate part—the rear coupling part 7 in the three-dimensional exploded view of Figure 4—and also the through hole 120 of the coupling cap 12.The modular coupling part 5 can thus be made of a different material than that used for the rest of the kinematic coupling portion 11; for example the rear coupling part 7 could be a little less hard to allow easier machining to produce the thread.

[0085] The rear coupling piece 7 used to make the rear kinematic coupling portion 11 can, on the contrary, be made of a harder material than that used for making the coupling cap 12.

[0086] The separation of materials chosen for the kinematic coupling portion 11 and the coupling cap 12 of the interconnecting piece 10 allows for the selection of an ultra-rigid material for the kinematic transmission of movements from the robotic arm 2 at the rear, at the level of the kinematic coupling portion 11—typically a material with a surface hardness between 450 and 900 Vickers—but, conversely, a slightly less rigid material at the front, at the level of the coupling cap, with respect to the surgical or dental instrument—typically a material with a hardness between 100 and 400 Vickers—in order to better absorb the vibrations experienced during the operation. In this way, each of the functional parts of the interconnecting piece of the coupling system can be optimized.

[0087] Figure 4 shows the correspondence between the shapes of the convex surface 12B of the coupling cap 12 and the internal surface 70 of the rear coupling piece 7. The relative positioning of the rear coupling piece 7 with respect to the coupling cap 12 is ensured by means of a positioning pin 8. This pin 8 is inserted, at the same time as the third pin 63 with respect to the standardized ring 340 and the contra-angle housing 32, into respective openings in the coupling cap 12 and the rear coupling piece 7 (NB: only the blind hole 71 is visible in this figure). The preferred method for joining these two parts is welding along a line following the peripheral edge 112 of the kinematic coupling portion 11, which is formed here by the rear coupling piece 7.As with the embodiment illustrated in Figure 2B, this weld line preferably extends over more than 240°, i.e. beyond the perimeter of all three coupling grooves (first groove 111A, second coupling groove 111B, third coupling groove 111C).

[0088] Figures 5A and 5B describe, similarly to Figures 2A and 2B, three-dimensional views of the contra-angle 31 in place of the right-hand piece 32. All the features and references relating to the coupling cap 12 and the kinematic coupling portion 11 being identical in every respect to those of Figures 2A and 2B, they will not be repeated in detail; it may simply be noted the reference of the standardized ring 340 at the connection interface 34 between the contra-angle and the micromotor 4, as well as the ends of the first pin 61 and the second fixing pin 62, as well as the end of the optical fiber channel 36 on top, as well as the irrigation channel 35 slightly further forward in relation to this connection area intended for the micromotor 4 (not shown in this figure, but which would appear, for this embodiment, in the same way as in Figure 3).

[0089] Although, according to the preceding embodiments, kinematic coupling portions 11 and coupling caps 12 made of different materials have been described, according to another preferred embodiment of the invention, the kinematic coupling portion 11 and the coupling cap 12 of the interconnecting piece are made as a single unit, in order to ensure rigid and optimal guidance or alignment with the robotic arm 2, particularly when the surgical or dental instrument 3 consists of a micromotor assembled to a handpiece. In such a case, there is no need for recalibration or adjustment of positions during installation. The axis of the motor and that of the transmission shaft of the handpiece are then intrinsically aligned and parallel to the connection plane between the handpiece and the robotic arm 2, which simplifies the navigation process and the positioning of the robotic arm.

[0090] According to a particularly advantageous variant, the coupling cap 12 can be made of austenitic stainless steel and the kinematic coupling portion 11 made of heat-treated hardened stainless steel.

[0091] According to another advantageous embodiment, at least one of the two components forming part of the interconnecting piece 10, between the coupling cap 12 and the kinematic coupling portion 11, can be coated with a thin layer obtained by a surface treatment such as carburizing, nitriding, galvanic or chemical deposition, or CVD (chemical vapor deposition) or PVD (physical vapor deposition) treatment.

[0092] As in Figure 3 described previously, Figure 5A also highlights the orientation of the direction vectors of the different coupling axes, namely the transverse coupling axis (AA) used for the robotic arm and the longitudinal coupling axis (BB) used for the surgical or dental instrument 3, which here no longer corresponds to that of the handpiece 31, but only to the longitudinal axis of the coupling nose 41 of the micromotor 4 (not shown in this figure).The first direction vector A associated with the transverse coupling axis (AA) is here again distinct from the second direction vector B associated with the longitudinal coupling axis (BB); according to the preferred embodiment illustrated in this figure the two direction vectors A and B are orthogonal; however, those skilled in the art will understand that such a configuration is not essential and that the fact that these direction vectors A, B are distinct is sufficient to improve the compactness of the coupling system and significantly reduce vibrations along the longitudinal coupling axis (BB) which is also the axis of rotation of the micromotor (4).

[0093] Figure 5B illustrates how easily the last degree of rotational freedom around the transverse coupling axis (AA) is fixed after all the others have been fixed by screwing the kinematic coupling portion 11 to the robotic arm 2.

[0094] In the foregoing, embodiments have been described that preferably use screwing both between the robotic arm 2 and the kinematic coupling portion 11, and between the coupling cap 12 and the surgical or dental instrument 3. However, according to another preferred embodiment for the realization of the invention, the coupling cap 12 of the interconnecting part 10 could be made directly on a surgical or dental handpiece 3 as a constituent element thereof.

[0095] In this way, the interconnecting part 10 can be easily produced as a single unit, for example by 3D printing, along with the handpiece, or it can be designed to be permanently attached to the handpiece by the user. This configuration prevents calibration drift over time due to the necessary assembly and disassembly for reprocessing the handpiece, i.e., cleaning and sterilizing it. In this case, where the single interconnecting part 10 is permanently attached to the handpiece by the user, it is logically cleaned and sterilized simultaneously with the handpiece, which is particularly advantageous for the user.

Claims

24 Demands 1. Coupling system (1) between a robotic arm (2) and a surgical or dental instrument (3), said coupling system (1) being formed by a single interconnecting piece (10) comprising on the one hand a kinematic coupling portion (11) intended for coupling with the robotic arm (2) and on the other hand a coupling cap (12) for coupling with said surgical or dental instrument (3) along a longitudinal coupling axis (BB).

2. Coupling system (1) between a robotic arm (2) and a surgical or dental instrument (3) according to claim 1, characterized in that the coupling between the coupling cap (12) and said surgical or dental instrument (3) is achieved by screwing.

3. Coupling system (1) according to claim 1, wherein the kinematic coupling portion (11) of said interconnecting piece (10) is arranged to be located at the rear of the surgical or dental instrument (3) in the mounted position.

4. Coupling system (1) according to any one of the preceding claims, wherein the kinematic coupling portion (11) and the coupling cap (12) of said interconnecting part (10) are made in a single piece.

5. Coupling system (1) according to any one of the preceding claims, wherein the kinematic coupling portion (11) and the coupling cap (12) of said interconnecting part (10) are made of 2 different materials.

6. Coupling system (1) according to claim 5, characterized in that the material used to make the coupling cap (12) has a hardness between 100 and 400 Vickers, and that the material used to make the kinematic coupling portion has a hardness between 450 and 900 Vickers.

7. Coupling system (1) according to any one of the preceding claims, wherein the coupling cap (12) of said interconnecting piece (10) comprises a concave surface (12A) intended to at least partially receive a micromotor (4) for a dental handpiece, and a convex surface (12B) at least partially enveloping said micromotor (4), when said micromotor (4) is connected to said surgical or dental instrument (3).

8. Coupling system (1) according to claim 7, wherein said concave surface (12A) of the coupling cap (12) of said interconnecting part (10) constitutes an internal bearing surface intended to conform to the external shape of said micromotor (4).

9. Coupling system according to claim 8, the cross-section of a front edge (121) of said coupling cap (12) extending over an angle of at least 150 degrees.

10. Coupling system according to claim 9, the cross section of said front edge (121) of said coupling cap (12) extending over an angle of up to 210 degrees.

11. Coupling system (1) according to any one of the preceding claims, wherein the kinematic coupling portion (11) comprises a tapped through hole (110) extending along a transverse coupling axis (AA), said transverse coupling axis (AA) having a first direction vector (A) and said longitudinal coupling axis (BB) having a second direction vector (B), said first and second direction vectors (A) and (B) being distinct.

12. Coupling system (1) according to claim 11, the transverse coupling axis (AA) of said tapped hole (110) being perpendicular to said longitudinal coupling axis (BB), and said coupling system (1) further comprising a series of coupling grooves (111) arranged in a plane perpendicular to said tapped through hole (110), said series of coupling grooves (111) being formed by a first coupling groove (111 A), a second coupling groove (111 B) and a third coupling groove (111 C) oriented mutually at 120° to each other symmetrically with respect to said tapped through hole (110).

13. Coupling system according to claim 12, wherein the kinematic coupling portion (11) and the coupling cap (12) of said interconnecting piece (10) are welded together, the weld line being in correspondence with the peripheral edge (112) of the kinematic coupling portion (11) and describing an angle greater than or equal to 240°, with respect to the axis of symmetry of the tapped through hole.

14. Coupling system (1) according to claim 12 or 13, the tapped through hole (110) being formed in a modular part (5) fixed to a through opening (113) of the kinematic coupling portion (11) by means of crimping, gluing or welding.

15. Coupling system (1), according to any one of claims 11 to 14, characterized in that the connection interface (34) between the micromotor (4) and the surgical or dental instrument (3) is in a substantially median position (M) between the front end (1210) of the coupling cap (12) and the tapped through hole (110).

16. Coupling system (1) according to any one of the preceding claims, wherein said surgical or dental instrument (3) is a contra-angle (31), and wherein said coupling cap (12) is fixed to said contra-angle (31) using a fastening system with integrated keying (6).

Images