Medical turbine handpiece

Abstract

The medical turbine handpiece (100) has a retaining means (19) within the headpiece (10) for rotatably holding a treatment tool, and further includes a release element (48) configured to interact with the retaining means (19) for releasing the treatment tool. The release element (48) can be operated using a cover (40), and further within the headpiece (10) is a sealing element (5) that acts between the cover (40) and a fixed bearing element (30) that annularly surrounds the retaining means (19).

Description

Technical Field

[0001] The present invention relates to a medical, particularly dental, turbine handpiece having a gripping sleeve and a headpiece disposed at the front end of the gripping sleeve. The present invention relates to means for efficiently sealing the head region of the handpiece from the surrounding environment.

Background Art

[0002] Dental instruments used for examination or treatment in a patient's oral cavity must be cleaned and sterilized before use to prevent the spread of bacteria. Therefore, it is known that after using such an instrument, it is washed on the one hand and sterilized on the other hand by an appropriate device to remove contaminating particles and, in some cases, kill existing bacteria. Such a reprocessing step is configured not only to act on the outer surface of the dental instrument but also to act on the inside.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0004] Despite these measures, it is useful to prevent bacteria from entering the internal region of the handpiece as much as possible beforehand. This problem arises particularly in the aforementioned dental turbine handpieces, where a runner located within the handpiece head region is driven by compressed air. This type of handpiece typically includes a retaining means for detachably holding a treatment tool and an associated operating system for selectively holding or releasing the tool, such as a dental drill. In this case, fluids potentially containing bacteria should be kept away from the internal rotor chamber and operating system, because such aspirated fluids are partially discharged again at a later time, which particularly increases the risk of bacterial transmission. Furthermore, foreign matter and corrosion-promoting fluids entering the internal space shorten the lifespan of the rotational support bearings and all other moving parts located within the handpiece head.

[0005] The aforementioned dental turbine handpieces have a problem in that, during use, at least temporarily, overpressure, and in some cases negative pressure, is generated within their internal space relative to the surrounding environment. When the handpiece is in operation, i.e., when the turbine rotor is driven by pressurized fluid, a certain amount of overpressure normally exists within the internal space of the head area, resulting in the air present being pushed outwards, which in itself is not a problem. However, when the supply of compressed air is stopped to interrupt operation, a temporary negative pressure may be generated within the head area during the short deceleration phase of the rotor, potentially causing ambient air to be drawn in. This creates a risk of repeated inhalation and expulsion of potentially bacteria-containing air, which should be avoided at all times.

[0006] Therefore, in the prior art, means are known to seal the internal space of the head region of a dental turbine handpiece from the surrounding environment. As will be described later, in this regard, it is known to use a lip seal or sealing sleeve that constitutes a seal lip acting on the outer circumference of a rotatably supported retaining element for a treatment tool. These seal lips have a valve function and open due to the overpressure present in the internal space during operation of the handpiece, thereby not acting on the rotating retaining element. This is not a problem because there is no risk of ambient air being drawn in due to the overpressure inside the handpiece head. When the compressed air supply is stopped, the seal lip closes due to the decrease in internal pressure and comes into contact with the outer circumference of the retaining element. This not only achieves sealing, but the rotor is also briefly decelerated by the contacting seal lip. Such lip seals are made of, for example, nitrile or silicone and undergo a certain amount of wear due to the above mechanism. A dental handpiece equipped with such a lip seal is described, for example, in Patent Document 1. Patent Document 2 also discloses a dental turbine in which the above-described type of seal lip is provided between the outer and inner rings of a bearing for a rotatable tool holder.

[0007] Furthermore, Patent Document 3 discloses a dental turbine in which an elastic sealing element, which functions as a so-called reverse suction stop, is mounted on the lid side of the housing, i.e., on the side opposite to the treatment tool. This sealing element, like the lip seal described above, comes into contact with the rotor, resulting in a frictional effect during turbine startup or deceleration, leading to wear of the sealing element.

[0008] Finally, Patent Document 4 also describes a dental turbine in which ball bearings are sealed for rotational support of a tool holder. However, the sealing or locking elements used here act between parts that rotate with each other and are therefore subject to a certain amount of wear, or merely form a labyrinth seal, which is insufficient against the intrusion of air containing bacteria.

[0009] Against this backdrop of prior art, the object of the present invention is to provide an improved means for sealing the head area of ​​a medical turbine handpiece. [Means for solving the problem]

[0010] This problem is solved by a turbine handpiece having the features of claim 1. Advantageous improved forms of the present invention are subject to the dependent claims.

[0011] The solution according to the present invention relates in particular to a means provided in the head region (Kopfbereich) on the lid side of the handpiece (Handstuecks) to achieve airtightness from the surrounding environment. As already mentioned, treatment tools, such as dental drills, are usually not fixedly attached to the handpiece but are detachably held by a rotating retaining means. Inside the headpiece (Kopfstuecks), a release element is located along the axis of rotation. This release element is configured to interact with the retaining means, and when the release element interacts with the retaining means, the retention of the treatment tool is released. The operation of the release element is usually performed via a lid of the headpiece, which is located opposite the tool receiving opening (Werkzeugaufnahmeoeffnung), and this lid is adjustable (verstellbar) in the direction of the axis of rotation between a resting position spaced away from the release element and an operating position that presses the release element to release the retention of the treatment tool.

[0012] The solution according to the present invention uses a sealing element that acts between a lid and a stationary bearing element that surrounds the retaining means in an annular shape for sealing in this area. This sealing element is attached to one of the two parts and is pressed against the sealing surface of the other element by prepressure, and is configured as a valve that separates from the sealing surface when the handpiece is operated. The advantage of the solution according to the present invention is that the sealing element itself does not rotate and does not come into contact with the rotating parts. Therefore, unlike the conventional solution, wear due to abrasion does not occur, so effective sealing is achieved while preventing wear of the seal.

[0013] Therefore, according to the present invention, a medical, particularly dental, turbine handpiece having a gripping sleeve and a headpiece is proposed. The headpiece is positioned at the front end of the gripping sleeve and has a tool receiving opening. The gripping sleeve has a fluid line that supplies fluid for driving the turbine wheel. Inside the headpiece, there are retaining means for rotatably holding the turbine wheel and treatment tools. The holding mechanism is positioned along the axis of rotation of the treatment tool. Furthermore, a release element is further positioned inside the headpiece along the rotation axis, configured to interact with the retaining means, and the release element releases the retaining of the treatment tool through interaction with the retaining means. Furthermore, the headpiece has a cover on the side opposite to the tool receiving opening, and this cover is adjustable in the direction of the rotation axis between a resting position separated from the release element and an operating position that presses against the release element to release the holding of the treatment tool.

[0014] According to the present invention, a sealing element is arranged within the headpiece that acts between a lid and a fixed bearing element that surrounds the retaining means in an annular shape. This sealing element is fixed to one of the lid and the bearing element, pressed against the other sealing surface of the bearing element and the lid by prepressure, and is configured as a valve, and is configured to separate from the sealing surface when the handpiece is in operation.

[0015] The sealing element is preferably configured as a so-called umbrella valve having a circular outer circumference, and is pressed against the corresponding sealing surface of the element on the side that is not fixed. Preferably, it is configured to open when the fluid overpressure is about 0.3 bar. This value ensures that the sealing element is reliably opened during operation of the handpiece when there is an overpressure of about 0.5 bar relative to the ambient air. On the other hand, this value ensures that the head area is reliably sealed not only when the handpiece is idle, but also during the deceleration process.

[0016] The sealing element according to the present invention is preferably formed in an annular shape, has a central opening, and its edge abuts against a lid or bearing element. For example, a circumferential groove can be provided in the lid or bearing element, and the edge of the central opening can be press-fitted into this groove. This enables the fixing of a highly reliable and airtight sealing element. Alternatively, the sealing element can be held in place by a separate, particularly annular, fixing element, sandwiched between the lid or bearing element.

[0017] Preferably, the sealing element extends from the cover or bearing element to which it is attached toward the sealing surface of the bearing element or cover, and when the valve is closed, the edge of the sealing element abuts against the sealing surface. In particular for this purpose, the sealing element may be configured to be concavely curved or concavely bent.

[0018] Alternatively, the sealing element may be configured in a rotational shape having a bent cross-sectional shape that is annular in the circumferential direction. In this case, the first leg of the cross-sectional shape preferably faces outward and is positioned substantially parallel to the lid and attached to the lid. On the other hand, the second leg of the cross-sectional shape extends substantially perpendicular to the first leg and is configured to be pressed against the side surface of the bearing element that forms the sealing surface by preload. This second leg performs a valve function and bends laterally when the handpiece is in operation, which, as described above, preferably occurs at an overpressure of about 0.3 bar.

[0019] In one aspect, the sealing element may be integrally formed of a suitable flexible material (flexiblen Material in the original text). In another aspect, it is also conceivable to configure the sealing element with a plurality of parts including an inner part attached to the lid or the bearing element and an annular sealing part attached to the inner part. The flexible material can be composed of, in particular, an elastomer, preferably a heat-resistant elastomer, particularly preferably a fluoroelastomer, and its thickness is particularly in the range of 0.2 mm ± 0.1 mm.

[0020] The bearing element may be constituted by the fixed-side outer ring of a rotary bearing that rotatably supports the holding means, or alternatively, may be constituted by a so-called bearing seat element that holds a rotary bearing that rotatably supports the holding means.

[0021] As described above, the lid is also used as an operating element for actuating the release element, and is preferably biased and supported in the rest position by a spring element, particularly a coil spring. In this case, the sealing element (or, when the bent cross-sectional shape forms an annulus, the second leg perpendicular to the cover) is arranged inside the spring element in a projection perpendicular to the rotary shaft. This ensures that the sealing mechanism according to the invention does not interfere with the function of the lid for actuating the release element. Also, with this configuration, the dimensions of the handpiece do not increase due to the sealing of the handpiece head (Handstueckkopfs in the original text). Rather, the solution according to the invention enables a very compact configuration of the handpiece head.

[0022] On the side opposite to the cover of the headpiece, since it is necessary to seal moving, especially rotating parts, the same method cannot be applied. Therefore, an annular seal element can be additionally provided on the side opposite to the cover, as in the procedure described in the prior art. This seal element acts as a sealing lip between the outer circumference of the holding means or the rotating part holding it and the wall of the surrounding headpiece. This seal will inevitably undergo a certain amount of wear, but when combined with the sealing means of the present invention at the opposite end, it ensures that the head area is sealed as optimally as possible against the surrounding environment, especially during the deceleration phase and in the resting state.

[0023] The present invention will be described in more detail below with reference to the accompanying drawings. The drawings are as follows.

Brief Description of the Drawings

[0024] [Figure 1] It is a cross-sectional view of a first exemplary embodiment of a medical turbine handpiece according to the present invention, in which the valve formed by the seal element is open. [Figure 2] It is another cross-sectional view of the handpiece according to the present invention, in which the fixing of the seal element partially coincides with that in FIG. 1, and the valve formed by the seal element is closed. [Figure 3] It is an enlarged view of a part of the handpiece according to the present invention, showing a second possible solution for fixing the seal element. [Figure 4] It is a cross-sectional view of a third exemplary embodiment of a turbine handpiece according to the present invention. [Figure 5] It is a view of a fourth exemplary embodiment of a turbine handpiece according to the present invention, in which the valve formed by the seal element is open. [Figure 6] It is a view of a fourth exemplary embodiment of a turbine handpiece according to the present invention, in which the valve formed by the seal element is closed. [Figure 7] It is a cross-sectional view of a fifth exemplary embodiment of a turbine handpiece according to the present invention. [Modes for carrying out the invention]

[0025] Figure 1 shows a cross-section of the front region of the dental handpiece 100 according to the present invention. The dental handpiece 100 consists of an elongated gripping sleeve 50 and a headpiece 10 positioned at its front end. As mentioned above, the dental handpiece 100 is a turbine handpiece and is driven by compressed air supplied from a dental supply unit. For this reason, a fluid line 51 extends along the gripping sleeve 50, through which compressed air is guided from the rear end to the head region 10, which contains a turbine. Similarly, an air line is also provided along the gripping sleeve 50, extending away from the head region 10, through which air that has left the turbine space is discharged again. This exhaust line is not visible in the selected illustration.

[0026] Inside the head region is a so-called turbine rotor 15, which is driven by compressed air supplied via a supply line 51. This causes a dental treatment tool, such as a dental drill, to rotate. The turbine rotor 15 consists of a substantially hollow cylindrical rotating part 17 extending along the axis of rotation I, surrounded by a turbine wheel 16 at approximately its central height. In some cases, the rotating part 17 and the turbine wheel 16 may be integrally configured, and in either case, a fixed connection is ensured so that the rotation of the turbine wheel 16, generated by the compressed air, is transmitted to the rotating part 17 and ultimately to a treatment tool not shown. The mounting of these parts into the headpiece 10, making them rotatable, is done by two bearings 20 and 25. These are located on either side of the turbine wheel 16 when viewed in the direction of rotation I, and each has an outer ring 21 or 26, an inner ring 22 or 27, and rolling elements, such as balls 23 or 28, positioned between them.

[0027] Treatment tools, such as dental drills, are housed in a replaceable rotating part 17. For this purpose, a so-called clamp sleeve 19 is provided inside the rotating part. The tool is inserted from below the handpiece head 10 into the tool receiving opening 18 of the rotating part 17, with its tool shank positioned within the clamp sleeve 19. The clamp sleeve 19, which rotates with the rotating part 17, engages with the end of the treatment tool, thereby causing the treatment tool to rotate with the rotating part 17.

[0028] A release element 48 is positioned in the upper region of the rotating part 17 to remove the treatment tool held in the clamp sleeve 19. The release element 48 has a wedge-shaped or pyramidal projection 49 on its underside. The release element 48 rotates with the rotating part 17 but is movable along the axis of rotation I, so that when the actuation element 40 is pushed down, the wedge-shaped projection 49 engages with the upper end region of the clamp sleeve 19. This causes the clamp sleeve 19 to widen slightly, releasing the clamping force applied to the shank of the treatment tool, or at least reducing it to the extent that the treatment tool can be removed.

[0029] The operation of the release element 48, particularly the downward push that causes the release element 48 to interact with the clamp sleeve 19, is performed by a cover 40 located at the upper end of the head section 10. The cover 40 closes the upper side of the head section housing, with its peripheral edge 43 housed within the housing of the headpiece 10, and is pressurized downward against the force of the coil spring 35. In the unloaded state shown in Figure 1, the cover 40 is pushed up to the upper stopper by the coil spring 35, and the cover 40 has a central projection 41 spaced apart from the release element 48. This prevents friction between the cover 40 and the release element 48 when the handpiece is in operation, i.e., when the rotating part 17 is rotating with the release element 48. This friction would, in one respect, produce an undesirable braking effect, and in other respect, cause rapid wear of the cover 40. Only when the lid 40 is pressed down (which usually occurs when the handpiece is in a non-operating state) does the central projection 41 come into contact with the upper surface of the release element 48, and as described above, the clamp holding of the treatment instrument is finally released.

[0030] The characteristics of the handpiece 100 according to the present invention, as described above, are also present in handpieces known in the prior art. Below, the means for efficiently sealing the inside of the headpiece 10 according to the present invention will be described in more detail.

[0031] Sealing the head area 10 is desirable because cleaning and sterilizing the internal area is significantly more difficult compared to cleaning the outer surface of the handpiece 100. Furthermore, as mentioned above, during the operation of the handpiece, i.e., when compressed air is introduced into the headpiece 10 via the fluid line 51 to drive the turbine wheel 16, a certain overpressure is generated inside the handpiece compared to the ambient environment. Typically, this type of turbine handpiece operates at a maximum of 300,000 revolutions per minute, resulting in an overpressure of approximately 0.5 bar.

[0032] On the other hand, when the compressed air supply is stopped, the turbine rotor 15 is decelerated from high speed to zero, and during this deceleration phase, for a period of about 1 second, negative pressure may be created inside the handpiece head 10. This causes outside air to be drawn in. This should be avoided at all times. At this point, the handpiece 100 is often located inside or near the patient's oral cavity, so the above presents a risk of potentially bacteria-contaminated air entering the inside of the headpiece 10. In addition, there is also a risk that the components of the bearing 20 or 25 may be damaged by the air thus drawn in.

[0033] As will be described in more detail below, in the prior art, it is known that the desired seal is achieved by using a seal lip positioned between the housing of the handpiece head 10 and the outer circumference of the rotating part 17. Such a seal element is considered to have the disadvantage that wear inevitably occurs because it acts between a fixed member and a rotating part. The present invention provides a solution that enables efficient sealing of the head area of ​​the handpiece 10, at least in the area of ​​the lid 40, while avoiding these disadvantages known in the prior art.

[0034] According to the present invention, a sealing element 5 is still used, particularly to seal the upper region of the handpiece head 10. However, this sealing element 5 is configured to act only between fixed, i.e., non-rotating components of the handpiece 100. This avoids the aforementioned problem of increased wear.

[0035] In the first exemplary embodiment shown in Figures 1 and 2 (in Figure 2, only the right side of the seal element 5 corresponds to the first exemplary embodiment), the seal element 5 is configured as an annular seal component made of a flexible material. Shown only in a cross-sectional view, the seal element 5, if it has a central opening, is fixed to the lid 40 through this central opening. More precisely, the aforementioned projection 41 of the lid 40 is provided with a circumferential groove 42 or a corresponding recess into which the edge of the central opening of the seal element 5 is press-fitted to achieve a form coupling. The seal element 5 is positioned on the outer circumference of the projection 41 of the lid 40 in a clamped and sealed state, thereby achieving the corresponding seal.

[0036] At the same time, the sealing element 5 extends outward from the mounting area on the projection 41 of the lid 40 in a concave curve, or in some cases in a concave bend, so that its circular edge 7 extends in the direction of the so-called bearing seat element 30. The function of the bearing seat element 30 is primarily to hold the upper bearing 20. In particular, an annular bearing seat element 30, for example, screwed into the upper region of the head housing, plays the role of holding the outer ring 21. Unlike the inner ring 22, the outer ring 21 does not rotate with the rotating part 17. Therefore, the bearing seat element 30 is also a fixed part within the headpiece 10 of the handpiece 100. For this reason, the sealing element 5 acting between the lid 40 and the bearing seat element 30 does not experience wear, as intended by the present invention.

[0037] However, the sealing effect is not intended to be permanent. Therefore, the sealing element 5 is intended to function as a valve that temporarily allows air to escape while preventing ambient air from entering the head area. The sealing element 5 constitutes a so-called umbrella valve, which opens when there is overpressure in the headpiece 10 and closes otherwise, creating a seal between the cover 40 and the bearing seat element 30 as described above.

[0038] The dimensions and material of the seal element 5 are selected to achieve the valve function described above, and in particular, it is intended that the valve opens at an overpressure of approximately 0.3 bar and closes otherwise, and contacts the bearing seat element 30 with the corresponding prepressure. In addition to the concave curved shape shown in the figure, the outer diameter of the seal element 5 is approximately 7-8 mm, and the width of the seal element 5, i.e., the distance from the edge of the central opening 6 to the outer circumference 7, is approximately 2-2.5 mm. However, these parameters may be changed depending on the selected material and the dimensions of the handpiece 100.

[0039] The material of the sealing element 5 is preferably a sterilizable material. As mentioned above, this material must have a certain degree of flexibility, and is therefore particularly an elastomer, and especially preferably a heat-resistant elastomer. The use of so-called fluoroelastomers (e.g., PTFE) is particularly preferred, in which case the sealing element 5 has a thickness of about 0.2 mm ± 0.1 mm.

[0040] Importantly, as shown in Figure 1, when the handpiece 100 is in operation, there is overpressure inside the headpiece 10 as described above, causing the seal element 5 to open. As can be seen from Figure 1, in this state, the outer edge 7 of the seal element 5 is slightly separated from the seal surface 33 on the end face side of the bearing seat element 30. When the handpiece 100 is in operation, air can flow out from the inside to the outside. At the same time, the internal overpressure prevents contaminated air from entering from the outside.

[0041] When the supply of compressed air is stopped, the internal pressure of the handpiece head 10 decreases, creating a temporary negative pressure relative to the ambient environment during the deceleration phase. In particular, when this pressure falls below approximately 0.3 bar (relative to ambient pressure), the seal element 5 closes, as shown in Figure 2, and its outer circumference 7 contacts the annular seal surface 33 of the bearing seat element 30. This sealed state is maintained not only during the deceleration phase but also when the handpiece 100 is not in operation. In other words, the seal element 5 opens only when the handpiece 100 is in operation, and at all other times, it efficiently seals the upper head region 10. This prevents ambient air from entering the area of ​​the upper bearing 20, as desired.

[0042] In the exemplary embodiments shown in Figures 1 and 2, the sealing element 5 is integrally constructed and fixed directly to the projection 41 of the lid 40 by form-engagement. In contrast, the left side of Figure 2 and the enlarged view of Figure 3 show an alternative method of fixing the sealing element 5. In this case, an annular so-called retaining device 44 is used as the fixing element. The retaining device 44 is pressed against the projection 41 of the lid 40 or connected to the projection 41 by other means, such as adhesive, and holds the sealing element 5 in the illustrated position by clamping. The retaining device 44 may be connected to the sealing element 5, for example, by adhesive, in which case the retaining device 44 is formed from a material that is more rigid than the sealing element 5 itself. In this case, too, plastic or metal is possible. In this case, the sealing element 5 may be configured to bend at its inner edge, which further improves the airtightness to the lid 40, as shown in Figure 3. In this modification, the other configurations and functions are the same as those shown in Figure 2.

[0043] As in the third embodiment shown in Figure 4, the seal element 5 may also be composed of multiple parts. In this case, the seal element 5 is first composed of an annular inner portion 8, which is positioned and fixed to the central projection 41 of the lid 40 in the manner described above. An annular sealing portion 9 is formed on the outer circumference of the inner portion 8, which is made of a more flexible material and interacts with the annular sealing surface 33 of the bearing seat element 30 in the same manner as described in relation to Figures 1 and 2.

[0044] In the illustrated exemplary embodiment, the seal portion 9 is configured to bend as shown, and a rib (Steg in the original text) formed on its outer circumference and aligned with the bearing seat element 30 is pressed against the corresponding sealing surface 33 of the bearing seat element 30 at its end face. This state occurs, as previously described, during the deceleration phase of the handpiece 100 or in a non-operating state. In contrast, in the operating state, the overpressure present in the head region 10 causes the seal element 5 to open as part of the valve function, and the annular rib separates from the upper surface of the bearing seat element 30. This state is shown on the right side of Figure 4. The above description applies to the material of the seal portion 9. In particular, the material is a heat-resistant material with flexibility suitable for achieving the valve function, such as a fluoroelastomer.

[0045] Figure 4 further shows that sealing of the head portion 10 can also be provided on the opposite side of the lid 40, i.e., on the underside of the rotating part 17. However, in this case, sealing between the two fixed parts of the handpiece head 10 cannot be achieved compared to the solution according to the present invention. Instead, an annular seal lip 60 is provided in the inner wall region of the head housing below the bearing 25, and this seal lip 60 interacts with the outer circumference of the rotating part 17. This seal lip 60 also preferably has a valve function and, when sufficient overpressure is present inside the handpiece 100, it moves away from the outer circumference of the rotating part 17, as shown on the right side of Figure 4. Only during the deceleration phase and in the non-operating state does it contact in a sealed state, as shown on the left side.

[0046] However, this seal lip 60 inevitably undergoes a certain amount of wear because it interacts with the rotating part 17. In contrast, such wear does not occur in the sealing of the upper region of the headpiece 10 according to the present invention. However, the seal lip 60 provided in the region of the insertion opening (Einsteckoeffnung) 18 is a useful additional element for achieving a good seal of the entire handpiece head 10. Therefore, this additional seal lip 60 can, in principle, also be provided in further exemplary embodiments of the sealing element 5 according to the present invention.

[0047] A fourth exemplary embodiment of the present invention is shown in Figures 5 and 6. This is very similar to the exemplary embodiments in Figures 1 and 2. However, here the seal element 5 is fixedly positioned on the bearing seat element 30 and interacts with the underside of the lid 40 in response to the internal pressure of the handpiece head 10.

[0048] Here too, the seal element 5 is configured as an umbrella valve, extending in a concave curve from the mounting portion to the bearing seat element 30 toward the lid 40. However, if there is overpressure inside the headpiece 10, the edge of the seal element 5 separates from the lid 40, as shown in Figure 5. On the other hand, during the deceleration phase or when the handpiece 100 is not operating, sealing is performed as shown in Figure 6. In this case as well, similar to the modified example in Figure 4, the seal element 5 can be composed of multiple parts, or, as in the embodiment of Figure 3, the seal element 5 can be held to the bearing seat element 30 by clamping with a separate part.

[0049] Finally, a fifth exemplary embodiment is shown in Figure 7. In this embodiment, the sealing element is configured in a rotational shape having a bent cross-sectional shape in the circumferential direction. The first leg 151 in the cross-sectional shape extends outward in a flange-like manner, is positioned substantially parallel to the lid 40, and is fixedly attached to the lid 40. For this purpose, the lid 40 may optionally have a surrounding annular recess or housing. Inside the first leg 151, a second leg 152 extends substantially perpendicular to the first leg 151. The second leg 152 is configured to press against the side surface of the bearing seat element 30, which constitutes the sealing surface 33, by pre-pressure. This second leg 152 performs a valve function while simultaneously providing the desired seal. As shown on the left side of Figure 7 (on the right side, the second leg 152 is in close contact with the bearing seat element 30 as a seal lip), in the presence of corresponding overpressure, the second leg 152 flexes laterally and moves away from the bearing seat element 30. In this case as well, the overpressure required for this purpose is preferably about 0.3 bar. The dimensions of the legs 151 and 152 are selected so that the second leg 152 is positioned inside the coil spring 50 and does not interfere with its function.

[0050] In this case as well, the sealing element 5 may be integrally constructed from the same material, or it may be constructed from different materials. In the latter case, as with the modified examples described above, the second leg portion 152 may be constructed from a more flexible material.

[0051] In all the exemplary embodiments shown, the sealing element 5 may also act between the outer ring 21 of the fixed upper bearing 20 and the cover 40. In this case as well, it is ensured that ambient air cannot enter the area of ​​the bearing 20 from above.

[0052] As already mentioned, the dimensions and shape of the seal element 5 are variable as long as the desired valve action is achieved. However, preferably, the seal element 5 is configured entirely inside the coil spring 35 so as not to interfere with its function. The coil spring 35 is located in the circumferential groove 31 of the bearing seat element 30 and needs to bias the cover 40 to its upper initial position without obstruction. In the fifth embodiment of Figure 7, as previously described, at least the second leg 152 is located inside the coil spring 50.

[0053] In summary, the means of the present invention significantly improve the possibility of sealing the head area of ​​a dental turbine handpiece. Furthermore, it is ensured that wear of the provided sealing element is minimized, or preferably completely eliminated.

Claims

1. A medical, especially dental, turbine handpiece (100), A gripping sleeve (50) and The headpiece (10) is positioned at the front end of the gripping sleeve (50) and has a tool receiving opening (18). Equipped with, The gripping sleeve (50) has a fluid line (51) that supplies fluid for driving the turbine wheel (16), Inside the headpiece (10), The turbine wheel (16) and, A holding means (19) for rotatably holding a treatment tool is provided, The holding means (19) is arranged along the rotation axis (I) of the treatment tool, Inside the headpiece (10), a release element (48) is further arranged along the rotation axis (I) and configured to interact with the retaining means (19). The release element (48), through interaction with the holding means (19), releases the holding of the treatment tool. The headpiece (10) further includes a cover (40) on the side opposite to the tool receiving opening (18), The lid (40) is adjustable in the direction of the rotation axis (I) between a resting position separated from the release element (48) and an operating position that presses against the release element (48) to release the holding of the treatment tool. A sealing element (5) is positioned within the headpiece (10) that acts between the lid (40) and the fixed bearing element (30) that surrounds the retaining means (19) in an annular shape. The sealing element (5) is attached to one of the lid (40) and the bearing element (30), and is pressed against the sealing surface (33) of the other of the bearing element (30) and the lid (40) by prepress. Furthermore, the sealing element (5) is configured as a valve and is configured to move away from the sealing surface (33) when the turbine handpiece (100) is in operation. A medical turbine handpiece characterized by the following features.

2. The sealing element (5) is configured as an umbrella-shaped valve having a circular outer circumference. The sealing element (5) is preferably configured to open when the fluid overpressure reaches about 0.3 bar. The medical turbine handpiece according to feature 1.

3. The sealing element (5) is configured in an annular shape and has a central opening, The edge (6) of the central opening is in contact with the lid (40) or the bearing element (30). The medical turbine handpiece according to feature 2.

4. The cover (40) or the bearing element (30) has a circumferential groove (42), The sealing element (5) has an edge of the central opening that is press-fitted into the groove (42). The medical turbine handpiece according to feature 3.

5. The sealing element (5) is held in place by a separate, particularly annular, fixing element (44) between the lid (40) or the bearing element (30). The medical turbine handpiece according to feature 3.

6. The sealing element (5) extends from the lid (40) or the bearing element (30) to which the sealing element (5) is attached, in the direction of the sealing surface (33) of the bearing element (30) or the lid (40), When the valve is closed, the edge (7) of the sealing element (5) abuts against the sealing surface (33). A medical turbine handpiece according to any one of claims 2 to 5.

7. The sealing element (5) is configured to curve in a concave shape or to bend in a concave shape. The medical turbine handpiece according to feature 6.

8. The sealing element (5) is configured in a rotational shape having a bent cross-sectional shape in an annular manner in the circumferential direction, The first leg portion (151) of the cross-sectional shape is preferably oriented outward, substantially parallel to the lid (40), and attached to the lid (40). The second leg portion (152) of the cross-sectional shape extends substantially perpendicular to the first leg portion (151) and is pressed against the side surface of the bearing element (30) constituting the sealing surface (33) by preload, and is configured to flex when the turbine handpiece (100) is in operation. The medical turbine handpiece according to feature 1.

9. The sealing element (5) is integrally formed from a flexible material. A medical turbine handpiece according to any one of the above claims, characterized in that...

10. The sealing element (5) is An inner portion (8) attached to the cover (40) or the bearing element (30), It is composed of a plurality of parts, including an annular sealing portion (9) formed of a flexible material and attached to the inner portion (8), A medical turbine handpiece according to any one of claims 1 to 6.

11. The aforementioned flexible material is an elastomer, preferably a heat-resistant elastomer, and particularly preferably a fluoroelastomer. The thickness of the flexible material is preferably in the range of 0.2 mm ± 0.1 mm. A medical turbine handpiece as described in 9 or 10.

12. The bearing element (30) is formed by the fixed outer ring of a rotary bearing (20) that rotatably supports the retaining means (19). A medical turbine handpiece according to any one of the above claims, characterized in that...

13. The bearing element (30) is composed of a bearing seat element that holds a rotary bearing (20) that rotatably supports the holding means (19). A medical turbine handpiece according to any one of claims 1 to 11.

14. The lid (40) is biased and supported in the resting position by a spring element (35), preferably a coil spring. The sealing element (5) is positioned inside the spring element (35) in a projection perpendicular to the rotation axis (I). A medical turbine handpiece according to any one of the above claims, characterized in that...

15. On the opposite side of the lid (40), there is further an annular sealing element (60) that acts between the outer circumference of the retaining means (19) or the rotating part (19) that holds the retaining means (19) and the surrounding wall of the headpiece (10). A medical turbine handpiece according to any one of the above claims, characterized in that...

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