WO2023020713A1

WO2023020713A1 - Hand-held medical or dental instrument

Info

Publication number: WO2023020713A1
Application number: PCT/EP2022/025372
Authority: WO
Inventors: Robert Laux
Original assignee: Robert Laux
Priority date: 2021-08-18
Filing date: 2022-08-12
Publication date: 2023-02-23
Also published as: DE102021121434A1

Abstract

A hand-held medical or dental instrument has a rotating tool that is coupled to a turbine for rotation, the turbine being rotatably mounted and being driven by a fluid jet. The turbine is a Tesla turbine and the fluid jet flows tangentially against one or more disks of the Tesla turbine.

Description

Medical or dental handheld instrument

The invention relates to a medical or dental medical hand-held instrument with a rotating tool.

EP 2 752 167 A1 discloses a fluid-operated dental handpiece with a turbine impeller, which has a plurality of curved turbine blades on a hub and is used to drive a tool in the dental handpiece. A drive fluid is supplied to the turbine wheel, which impinges on the turbine blades and drives the turbine wheel, which also drives the tool. In order to improve efficiency, the rear side of the turbine blades has a concave surface which is curved towards the front side of the turbine blades.

The object of the invention is to create a hand-held medical or dental instrument of simple construction with a rotatably mounted turbine and a rotating tool, the instrument being characterized by a high level of efficiency. This object is achieved according to the invention with the features of claim 1 . The dependent claims indicate expedient developments.

The medical or dental hand-held instrument is particularly suitable for processing soft or hard human or animal tissue, which is processed using a rotating tool in the instrument. The hand-held instrument is, for example, a handpiece or angle piece, in particular a dental turbine such as a drill, in particular a dental drill with a drilling tool.

The instrument has a rotating or rotatably mounted tool, which is coupled to a rotatably mounted turbine and driven by the turbine. The tool and the turbine can be mounted coaxially and connected to one another in a torque-proof manner. However, a non-coaxial mounting of tool and turbine is also possible, for example with parallel offset axes of rotation or with axes of rotation aligned at an angle to one another. Advantageously, the tool and the turbine are directly rotationally connected, so that no transmission element, such as a gear wheel, is arranged between the tool and the turbine. In an alternative embodiment, the drive movement of the turbine is transmitted to the tool via a transmission with at least one moving component in between, such as a gearwheel.

The turbine is driven by a fluid jet that is guided through a housing of the instrument. The fluid is either a liquid or a gaseous fluid, preferably air, in which case the gaseous fluid can be designed as an aerosol and correspondingly enriched with water droplets.

The turbine of the hand-held instrument according to the invention is designed as a Tesla turbine, which has one or more discs on a turbine body rotatably mounted in the housing, the plane of the discs being orthogonal to the axis of rotation. The disk or disks of the Tesla turbine are tangentially flown by the fluid jet. The oncoming flow transfers energy from the fluid jet to the disk or disks through viscosity and adhesion, driving the Tesla turbine. The drive movement is transferred from the Tesla turbine to the tool so that the tool rotates about its axis of rotation.

The Tesla turbine design has the advantage that a high level of efficiency can be achieved. The efficiency is usually higher than that of a turbine with turbine blades, which is driven solely by a fluid jet impinging on the turbine blades.

In addition, the Tesla turbine produces less noise due to the even power transmission at the same speed. Turbine blades, on the other hand, produce pulsating sound at high speeds with uncomfortable high frequencies, which is not the case with the Tesla turbine.

The Tesla turbine is preferably designed without blades. Alternatively, blades can also be arranged on the Tesla turbine, onto which the fluid jet impinges and via which the Tesla turbine is additionally driven. When the flow hits the pane or panes, the fluid flow is decelerated and deflected in the direction of the center of the pane. The fluid spirals inwards; kinetic energy continues to be transferred to the disk or disks.

The turbine body, which is the carrier of the disc or discs, can be designed as a shaft whose longitudinal axis is formed by the axis of rotation. When the shaft is designed as a hollow shaft, openings can be made in the wall of the hollow shaft, through which the fluid of the fluid stream flows into the interior of the hollow shaft, whereupon the fluid is discharged axially through the hollow shaft.

It is also advantageous that the Tesla turbine has a simple structural design and can be manufactured correspondingly inexpensively. The disk or disks on which the fluid jet flows tangentially have a simple structure that is easy to manufacture. No complex three-dimensional shapes are required as in turbine blades.

In an expedient embodiment, a turbine body, which is mounted rotatably in the housing and forms the axis of rotation, and the disk or disks of the Tesla turbine are designed in one piece. This represents a lower production cost than the individual production and subsequent connection of the turbine body and disk or disks and can be easily implemented due to the relatively small dimensions of the Tesla turbine when used in medical or dental instruments. The one-piece execution of Turbine bodies and the disc or discs can be produced, for example, using CNC laser technology.

Furthermore, it is advantageous that the fluid flow is slowed down considerably after it hits the pane or panes, which facilitates a targeted outflow and forwarding of the fluid. The kinetic energy of the fluid jet, which is released when braking, is converted into rotational energy of the Tesla turbine.

It is also advantageous that the Tesla turbine rotates at high speeds. In the case of a dental drill, for example, this high speed can be transmitted directly from the Tesla turbine to the drilling tool.

In principle, it is sufficient for the Tesla turbine to have only one disk, the side surface of which is subjected to the flow of fluid jet in the tangential direction. In the case of tangential flow, the fluid jet runs parallel or approximately parallel to the plane with the surface of the disk against which the flow occurs, with a small angle between the fluid jet hitting the surface of the disk and the surface of the disk being possible, which is preferably a maximum of 10° or a maximum of 20°.

According to a preferred embodiment, a plurality of disks are arranged parallel to one another and spaced apart from one another, for example five or more disks, with a fluid jet being guided through each gap between two disks. The disks of the Tesla turbine are rigidly connected to the turbine body forming a shaft, with the planes of the disks being orthogonal to the axis of rotation of the Tesla turbine. In the case of two or more adjacent disks of the Tesla turbine, efficiency is further increased because the jet of fluid directed into the spaces between the disks drives both immediately adjacent disks.

The diameter of the disk or disks of the Tesla turbine is, for example, 9 or 10 mm, in particular a maximum of 9 mm or a maximum of 10 mm or a maximum of 12 mm, the distance between two adjacent disks is, for example, at least 0. 1 mm, optionally at 0 . 3mm or 0 . 4 mm, and the disc thickness, for example, 0 . 3mm . The shaft-shaped turbine body forming the axis of rotation, on which the disk or disks are arranged, has a diameter of 3 mm, for example.

An overall Tesla turbine diameter of 12mm or 15mm is also possible, particularly in the event that the diameter of the turbine body is added to the functional disc diameter.

The Tesla turbine with the turbine body and the discs is advantageously designed as a one-piece component and can be produced by removing material, in particular by turning, milling or drilling. The Tesla turbine consists, for example, of metal such as titanium or stainless steel, of ceramic, for example zirconium, of glass fiber or of a fiber-reinforced plastic, in particular a plastic reinforced with carbon fibers.

With the aforementioned relatively small diameter of, for example, 9 mm or 10 mm, the Tesla turbine produce well as a one-piece component and in material removal. For example, a slice spacing of 0 . 3 mm or 0 . 4 mm can easily be produced in the material-removing manufacturing process up to a radial depth of, in particular, 5 mm or 6 mm. In particular, the use of metal, ceramics or composites enables production as a one-piece component. A deeper radial removal for the production of larger components is not achievable in terms of production technology within the scope of an economical production. The production of the Tesla turbine using the 3D printing process is usually not effective because the desired high speeds cannot be achieved without damage from the materials intended for this purpose. This limits the use of the Tesla turbine on this scale in the prior art to use as a pump.

The Tesla turbine can operate in a speed range of the order of 200 . 000 revolutions per minute (rpm) or more, preferably at least 50 . 000 rpm or at least 100 . 000 rpm .

In the housing of the hand-held instrument, a supply channel for the fluid is advantageously introduced, which drives the disc or discs of the Tesla turbine as a fluid jet. In the region of its mouth, on the side facing the Tesla turbine, the feed channel is oriented at an angle which, with the disk or disks in the Tesla turbine, is at most 10° or at most 20°, but preferably at 0 ° lies . This ensures that the fluid jet, with which the fluid exits the supply channel and flows against the disk or disks of the Tesla turbine, is exactly tangential, or at least is directed approximately tangentially to the disk or disks.

According to another expedient embodiment, the housing has a housing handle and a housing head, the housing handle receiving the supply channel and the housing head receiving the Tesla turbine and the rotating tool that is driven by the Tesla turbine.

According to yet another advantageous embodiment, a discharge channel is arranged in or on the housing, via which the fluid can be discharged downstream of the disk or disks. The discharge channel preferably branches off on the side of the housing facing away from the tool and can either run inside the housing or on the outside of the housing, but is firmly connected to it. The discharge channel can be arranged parallel to the supply channel in the housing in the further course, which connects to the branch downstream of the Tesla turbine. In the case of a dental bur or any other bur, the discharge channel runs in sections parallel to the supply channel in the housing handle.

In an alternative embodiment, the discharge channel has an orifice opening on its side facing away from the Tesla turbine, which points in the direction of the tool. Accordingly, the fluid is directed downstream of the Tesla turbine in the direction of the object to be processed. The fluid hits the object to be processed and cools it.

According to yet another advantageous embodiment, several connecting webs are distributed over the circumference between the Disks of the Tesla turbine arranged. The tie bars stabilize and support the position of the disks on the turbine body and ensure consistent spacing between the disks. The connecting webs are hit by the fluid jet as it flows, which exerts an additional impulse on the discs, which contributes to the drive of the Tesla turbine. The Tesla effect, via which the turbine is mainly driven, remains unaffected or at least largely unaffected.

It can be expedient for the connecting webs to have only a partial extent in the radial direction, based on the radius of the discs. Accordingly, the radial extent of the connecting webs is smaller than the disk radius. This has the advantage that the fluid, which flows in the direction of the center of the pane due to the Tesla effect, can flow past the connecting webs and remains at least largely unaffected by the connecting webs. The connecting webs can, for example, be designed in such a way that at least two connecting pieces are arranged radially one behind the other between the discs, with a radial passage being located between the connecting webs. The fluid can flow in the direction of the center of the disk through this radial passage.

According to a further advantageous embodiment, the direction of flow of the driving fluid can be reversed to reverse the direction of rotation of the Tesla turbine, so that the fluid is supplied via the discharge channel and discharged via the supply channel. This execution and procedure is particularly suitable for the case that supply and Drainage channel run parallel to each other in the housing. On the one hand, the reversal of the direction of rotation allows additional processing options, on the other hand, the rotating tool wears more evenly, which increases its service life.

Further advantages and expedient designs can be found in the further claims, the description of the figures and the drawings. Show it :

Fig. 1 a section through a dental drill with a Tesla turbine for driving a drilling tool,

Fig. 2 the Tesla turbine in detail,

Fig. 3 the Tesla turbine with the drilling tool inserted,

Fig. 4 is a perspective view of the Tesla turbine,

Fig. 5 another perspective view of a Tesla

Turbine in a design variant with connecting webs between the discs of the Tesla turbine,

Fig. 6 shows a section through a dental drill with a drainage channel for draining the fluid that drives the Tesla turbine in the direction of the drilling tool, with the drainage channel branching off axially on the side opposite the drilling tool, Fig. 7 shows a section through another embodiment variant of a dental drill, in which the discharge channel branches off in the side area of the Tesla turbine.

In the figures, the same components are provided with the same reference symbols.

In Fig. 1 shows a dental drill 1 as a dental instrument, which has a housing 2 which includes a housing handle 2a and a housing head 2b. Housing handle 2a and housing head 2b are made in one piece. A supply channel 3 for supplying a fluid is introduced into the housing grip 2a, which is guided in the form of a fluid jet 4 in the direction of a Tesla turbine 5 according to the arrow shown. The fluid that is introduced via the supply channel 3 is, for example, an aerosol consisting of air with water droplets attached.

The Tesla turbine 5 is rotatably mounted in the housing head 2b. A tool in the form of a drilling tool 6 is connected in a torque-proof manner to the lower section of the Tesla turbine 5, with the drilling tool 6 protruding downwards from the housing head 2b. The Tesla turbine 5 is mounted in the housing head 2b via two axially spaced bearing points 7 and 8, in which a turbine body 10 of the Tesla turbine 5 is rotatably received.

As Fig . 1 in conjunction with the other Figs. 2 to 4, the Tesla turbine 5 has a plurality of discs 9 which are axially superimposed and spaced apart from one another and between which there is a small space into which the fluid jet 4 can penetrate. Total are in From exemplary embodiment 8 superimposed disks 9 are arranged in the Tesla turbine 5 . The disks 9 are connected in a torque-proof manner to the turbine body 10 of the Tesla turbine 5, with the turbine body 10 being designed as a shaft which is supported and mounted at the bearing points 7 and 8 in the housing head 2b. The discs 9 are firmly connected to the turbine body 10 .

The feed channel 3 makes a small angle of approximately 10° with the plane of the disks 9 . Accordingly, the fluid jet 4 also hits the disk package with the disks 9 at an angle of approximately 10° and enters the interspaces between adjacent disks 9 at this angle. In the interstices, the fluid jet 4 moves tangentially in relation to the longitudinal axis 11 of the Tesla turbine 5 and the drilling tool 6 and thus also parallel to the disk plane of the disks 9 . The fluid jet 4 transfers its kinetic energy to the disks 9 through viscosity and adhesion, thereby driving the Tesla turbine 5 and thus also the drilling tool 6 .

When the disks 9 of the Tesla turbine 5 are flowed against, the fluid that is supplied in the fluid jet 4 migrates spirally inwards in the direction of the longitudinal axis 11 , kinetic energy continuing to be transmitted to the disks 9 . The shaft-shaped turbine body 10 can be designed as a hollow shaft, at least in the area of the discs 9 and in the axial section opposite the tool holder, it being possible for openings to be introduced in the wall in the area of the discs 9 through which the fluid passes. The fluid inside the hollow shaft 10 can then be discharged axially upwards, for example. In Fig. 5 shows an embodiment variant of a Tesla turbine 5 which has the same basic structure with a plurality of disks 9 arranged parallel to one another and spaced apart on a shaft-shaped turbine body 10 . In addition, several connecting webs 12 are arranged between the disks 9 , distributed over the circumference, which extend axially over the entire disk assembly and ensure additional stabilization and a constant spacing between the disks 9 . The connecting webs 12 can either extend in the radial direction up to the shaft 10 or, as shown in the left-hand area of the image, two or more connecting webs 12 are arranged one behind the other in the radial direction, but overall they have a smaller radial extent than the disk 9, so that an intermediate Gap between the connecting webs 12 is located. In addition to stabilizing the discs 9 , the connecting webs 12 also serve as turbine blades on which the fluid jet 4 impinges, as a result of which an additional momentum transfer from the fluid jet 4 to the Tesla turbine 5 is provided.

In Fig. 6 shows an embodiment variant of a dental drill 1, in which a discharge channel 13 branches off axially from the housing head 2b of the housing 2 and is guided through the housing grip 2a, but is offset laterally to the supply channel 3 in order to prevent the fluid flows in the supply channel 3 and the To avoid discharge channel 13. The diversion of the discharge duct 13 takes place immediately after the shaft-shaped turbine body 10 on the side facing away from the drilling tool 6 in the axial direction. So it can Fluid downstream of the disks 9 can be derived from the shaft 10 into the discharge channel 13 .

On its side opposite the branch, the discharge channel 13 has an orifice opening in the side region of the housing handle 2a, the orifice opening 14 facing the drilling tool 6 . The fluid emerges from the dental drill 1 via the orifice 14 and hits the object to be machined by the drilling tool 6, as a result of which it is cooled.

FIG. 7 shows a further variant embodiment of a dental drill 1, in which the discharge channel 13 is arranged in an alternative way. The drainage channel 13 is fully integrated into the housing handle 2 . The discharge channel 13 branches from the radial side area of the Tesla turbine 5 at the level of the discs 9 and receives the outflowing fluid, which is then guided downwards and thus transversely to the longitudinal extent of the housing handle 2a in the direction of the drilling tool 6. The discharge channel 13 is guided completely within the housing handle 2a and the housing head 2b.

In yet another alternative embodiment, the discharge channel 13 does not open out in the direction of the drilling tool 6, but is led back parallel to the supply channel 3 through the housing handle 2a.

Claims

patent claims

1. Medical or dental hand-held instrument with a rotating tool (6) which is rotatably connected to a rotatably mounted turbine which is driven by a fluid jet (4) which is guided through a housing (2) of the instrument, characterized in that that the turbine is designed as a Tesla turbine (5), one or more discs (9) of the Tesla turbine (5) being tangentially flown by the fluid jet (4).

2. Instrument according to claim 1, characterized in that the Tesla turbine (5) has a plurality, in particular at least five discs (9) which are arranged parallel to one another and which are spaced apart from one another.

3. Instrument according to claim 1 or 2, characterized in that the housing (2) has a supply channel (3) for the Tesla turbine (5) driving fluid, wherein the supply channel (3) with the plane of the disk or disks (9) of the Tesla turbine (5) occupies an angle which is a maximum of 10°.

4. Instrument according to one of claims 1 to 3, characterized in that a discharge channel (13) is arranged in or on the housing (2), via which the fluid can be discharged downstream of the disk or disks (9) of the Tesla turbine (5). is.

5. Instrument according to claim 4, characterized in that the discharge channel (13) branches off on the side facing away from the tool (6) on the housing (2).

6. Instrument according to claim 4 or 5, characterized in that the orifice (14) of the discharge channel (13) on the side facing away from the Tesla turbine (5) points in the direction of the tool (6).

7. Instrument according to claim 4 or 5, characterized in that the discharge channel (13) is arranged at least in sections parallel to the supply channel (3) in the housing (2).

8. Instrument according to any one of claims 1 to 7, characterized in that distributed over the circumference a plurality of connecting webs (12) between the discs (9) of the Tesla turbine (5) are arranged.

9. Instrument according to claim 8, 17 characterized in that the connecting webs (12) in the radial direction only have a partial extension based on the radius of the disks (9).

10. Instrument according to claim 9, characterized in that at least two connecting webs (12) are arranged radially one behind the other between the discs (9), with a radial passage lying between the connecting webs (12).

11. Instrument according to one of claims 1 to 10, characterized in that a rotatably mounted in the housing turbine body (10) of the Tesla turbine (5) and the disc or discs (9) are integrally formed.

12. Instrument according to claim 11, characterized in that the Tesla turbine (5) is produced by material removal.

13. Instrument according to one of claims 1 to 12, characterized in that to reverse the direction of rotation of the Tesla turbine (5), the fluid can be supplied via the discharge channel (13) and can be derived via the supply channel (3).

14. Instrument according to any one of claims 1 to 13, characterized by an embodiment as a dental drill (1). 18

15. Instrument according to any one of claims 1 to 14, characterized in that the Tesla turbine (5) is made of metal, in particular titanium.