Holding base

Abstract

A holding base for holding a handpiece of an oral digital impression instrument, the holding base comprising an outer housing comprising a bottom cover and an upper housing body, the upper housing body being fixedly fitted onto the bottom cover, the upper housing body having a central holding recess recessed from its upper surface toward the bottom cover, the holding base further comprising a counterweight, the counterweight being configured to be coupled to the upper surface of the upper housing body, counterweights are secured to the bottom cover inside the outer housing and extend vertically upward from the bottom cover, where the counterweights are disposed circumferentially around the central retention recess to be distributed substantially centrosymmetric with respect to the retention recess. The holding base can stably hold an object and has a sufficiently small size.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of oral digital impression instrument, and concretely relates to a holding base. BACKGROUND

[0002] Oral digital impression instrument or oral scanner usually has a handpiece, and an operator can operate the handpiece to scan a desired target or area. In the idle case, the handpiece will be held by a base for subsequent use. According to the design of the handpiece and the base, the handpiece usually has two placement modes: flat placement and substantially vertical placement. In the case of vertical placement of the handpiece, a part of the handpiece is usually inserted into a groove of the base to ensure balance.

[0003] In order to ensure that the base on which the product is placed is maintained stable, a counterweight is usually placed in the base. The counterweight of the base in the prior art is usually a flat plate structure, so it is also called a counterweight plate. Conventionally, the counterweight plate has two arrangements: arranged under the base; and arranged in the base. In the case of vertical placement of the handpiece, the following problems may exist: in the design in which the counterweight is arranged under the base, under the same weight requirement, the center of gravity of the base will be high, that is, it cannot be made low, which will result in that the height of the handpiece is too high, thereby increasing the difficulty of stable placement of the handpiece. In the design in which the counterweight is arranged in the base, if the flat plate-shaped counterweight plate is to be placed in the base product that is desired to be made low, the horizontal size of the base will be increased due to the need for the counterweight plate to avoid the groove of the base. In other cases, if the flat plate-shaped counterweight is considered to be arranged vertically around the base, the additional fixing components will greatly increase the production cost and assembly. In addition, if the size of the counterweight plate is reduced to maintain the small size of the base, the weight of the counterweight plate may not be sufficient to stably hold the handpiece, and there is a possibility of tipping when the handpiece is placed.

[0004] Therefore, at present, it is desired to have a base that can have a small enough size while being able to stably hold the handpiece. SUMMARY

[0005] In order to solve the problem of excessive size or insufficient counterweight of the existing base for the handpiece, the utility model provides a holding base, which can have a small enough size while being able to stably hold the handpiece.

[0006] In embodiments of the present application, the holding base is used to hold an object having a handpiece, and in more specific embodiments, the holding base is configured to hold and charge a handpiece of a digital dental impression device. The holding base includes an outer housing including a bottom cover and an upper housing body fixedly coupled to the bottom cover, the upper housing body having a central holding recess recessed from an upper surface thereof toward the bottom cover. The holding base further includes a counterweight fixed to the bottom cover inside the outer housing and extending vertically upward from the bottom cover, wherein the counterweight is disposed to circumferentially surround the central holding recess to be substantially centrally symmetrically distributed with respect to the central holding recess.

[0007] In embodiments of the present application, the counterweight is integrally formed as an annular counterweight. The single integral counterweight is more convenient to install than multiple counterweights.

[0008] More advantageously, the counterweight is cut from a circular steel tube to reduce cost.

[0009] Also advantageously, the counterweight extends vertically upward from the bottom cover to substantially the same height to achieve uniform weight distribution inside the housing.

[0010] In embodiments of the present application, the holding base further includes a charging FPC board to achieve a charging function. The charging FPC board is installed inside the outer housing, wherein a charging connector is disposed on the charging FPC board and surrounded by the counterweight. The use of the charging FPC board can optimize the circuit layout to help reduce the overall size of the holding base and leave more size for the counterweight to achieve greater counterweighting.

[0011] Further, the counterweight has a receiving portion, and the charging FPC board is bendable such that a portion of the charging FPC board is coupled to and fixed with the receiving portion of the counterweight, thereby reducing the size requirement of the holding base.

[0012] Advantageously, the bottom cover has a positioning portion configured to position the counterweight with respect to the bottom cover to facilitate installation of the counterweight.

[0013] In embodiments of the present application, the upper housing body includes a housing body and a top cover installed on the housing body to form the central holding recess recessed toward the bottom cover, wherein the top cover has an opening to expose the charging connector.

[0014] Advantageously, at least one of the top cover and the bottom cover, preferably both, has a ventilation portion in fluid communication with the interior of the outer housing, thereby facilitating heat dissipation inside the outer housing.

[0015] More advantageously, the handpiece has an air inlet at its bottom and an air outlet, which, when the handpiece is held by the holding base, are at least partially aligned with the top cover vent, so that air can enter the handpiece interior from the external environment via the bottom cover vent, the top cover vent and the air inlet, and the air outlet is at least partially aligned with the top cover vent, so that air can pass from the handpiece interior to the external environment via the air outlet, the top cover vent and the bottom cover vent. The cooperation of the air inlet and the air outlet with the vents of the holding base facilitates the heat dissipation of the handpiece.

[0016] Optionally, a liquid discharge channel is formed inside the outer housing, which communicates the top cover vent with the bottom cover vent and is laterally sealed. The liquid discharge channel can reduce the accumulation of liquid that can slide from the handpiece to the central holding recess of the holding base.

[0017] In the embodiments of the present application, the bottom cover further has a support portion supporting the central holding recess. The support portion can on the one hand provide certain support for the top cover, so that the durability of the handpiece during placement is improved, and on the other hand can provide partial wind channel partial isolation, so that the air inlet and outlet of the handpiece are more conveniently conducted from the top cover to the bottom cover.

[0018] In additional embodiments, the counterweight has a recess and a magnet is mounted in the recess, and wherein the object has a Hall sensor associated with the magnet. The position relationship between the object and the counterweight is sensed by the Hall sensor, and it can be determined whether the object has been held by the holding base.

[0019] The additional features and advantages of the holding base described will be set forth in the detailed description that follows, and will be apparent to those skilled in the art from the detailed description including the following description as well as the annexed drawings, which include the following: BRIEF DESCRIPTION OF DRAWINGS

[0020] The technical features of the present application with reference to the above objects are clearly described in the following claims, and the advantages thereof are apparent from the following detailed description with reference to the accompanying drawings, which show by way of example the preferred embodiments of the present application, without limiting the scope of the inventive concept.

[0021] Figure 1 A schematic view of a holding base according to an embodiment of the present application is shown;

[0022] Figure 2 A schematic perspective view of a housing body of a holding base according to an embodiment of the present application is shown;

[0023] Figure 3Fig. 1 shows a schematic perspective view of a top cover of a holding base according to an embodiment of the present application;

[0024] Figure 4 Fig. 2 shows a schematic perspective view of a top cover of a holding base according to an embodiment of the present application, viewed from another angle;

[0025] Figure 5 Fig. 3 shows a top view of a holding base according to an embodiment of the present application;

[0026] Figure 6 Fig. 4 shows a side sectional view of a holding base according to an embodiment of the present application;

[0027] Figure 7 Fig. 5 shows a schematic perspective view of a bottom cover of a holding base according to an embodiment of the present application;

[0028] Figure 8 Fig. 6 shows a schematic view of a charging FPC board of a holding base according to an embodiment of the present application, wherein the charging FPC board is not bent;

[0029] Figure 9 Fig. 7 shows a schematic perspective view of a charging FPC board of a holding base according to an embodiment of the present application, wherein the charging FPC board is bent;

[0030] Figure 10 Fig. 8 shows a schematic perspective view of a bottom cover of a holding base according to an embodiment of the present application, wherein the bottom cover is mounted with a charging FPC board;

[0031] Figure 11 Fig. 9 shows a schematic perspective view of a weight of a holding base according to an embodiment of the present application; and

[0032] Figure 12 Fig. 10 shows a schematic perspective view of a bottom cover of a holding base according to an embodiment of the present application, wherein the bottom cover is mounted with a charging FPC board and a weight.

[0033] Reference signs

[0034] 1 - handpiece; 2 - air inlet; 3 - air outlet;

[0035] 100 - upper shell body;

[0036] 110 - shell body; 111 - inner edge; 1111 - through hole; 112 - shell body opening; 113 - shell body buckle part;

[0037] 120 - top cover; 121 - upper flange; 1211 - protruding part; 122 - central holding recess; 123 - top cover opening; 124 - top cover ventilation part;

[0038] 200 - bottom cover;

[0039] 201 - bottom cover snap portion; 202 - bottom cover vent portion; 203 - support portion; 204 - first boss;

[0040] 205 - limit post; 206 - charger securing portion; 207 - second boss; 208 - locating portion;

[0041] 300 - charging FPC board;

[0042] 301 - first portion; 302 - second portion; 303 - third portion; 304 - fourth portion;

[0043] 310 - charging connector;

[0044] 400 - counterweight;

[0045] 401 - receiving portion; 402 - recess; 403 - magnet. DETAILED DESCRIPTION

[0046] The utility model will be explained in further detail below in conjunction with the drawings and embodiments, but not as any limit on the utility model.

[0047] For ease of explanation, in the following embodiments, it is assumed that the holding base is fixed on a horizontal surface, but it will be appreciated by those skilled in the art that the holding base according to the utility model can be fixed on a non-horizontal surface. The orientation terms "upper", "lower", "horizontal", "vertical" and the like used herein are also described based on the assumption that the holding base is fixed on a horizontal surface for ease of understanding, but those skilled in the art will appreciate that these orientations are not necessarily so in other cases (e.g. when mounted on an inclined stand). Further, the terms "circumferential", "central" and the like used herein are described with reference to a top-down perspective view of the holding base. Likewise, the "bottom" of the handpiece refers to the portion that is supported by the bottom surface of the recess of the holding base when the handpiece is held by the holding base. Figure 5

[0048] The term "substantially" used herein allows for a 10% deviation in the arrangement of components or portions. For example, "substantially vertical" means that it can be inclined by no more than 10 degrees with respect to a vertical axis (e.g. in embodiments of the utility model, the substantially vertical central holding recess is inclined by 5 degrees with respect to a vertical axis); "substantially the same height" means that the upper or lower surface of the counterweight can have undulations or be jagged in shape.

[0049] The "upper surface" and "lower surface" of a certain component described herein refer to the surface of the component that is seen from a top-down perspective and a bottom-up perspective, respectively, when the component is installed in place. ​

[0050] The description herein that a certain component is "in a substantially central symmetric distribution with respect to the holding recess" is used to indicate that the cross-sectional shape of the counterweight in any horizontal plane (including the case where the distance is zero, which is the lower surface) at a distance from the lower surface of the counterweight is rotationally symmetric with respect to the center of gravity of the cross-sectional shape of the holding recess in the horizontal plane, but the shape such as a threaded hole can be ignored.

[0051] The term "cutting" used herein refers to the separation of the target from the raw material, and does not exclude subsequent processing of the target, such as tapping, etc. It should be understood that the trajectory of "cutting" is not necessarily a continuously derivable line, but can be a line with inflection points. For example, cutting can be performed on the raw material so that the finished product after cutting has, for example, an L-shaped shape.

[0052] The description herein "flexibly connected" is used to indicate that the two parts of the connection can be bent relative to each other.

[0053] For the sake of clarity, the same components are designated by the same reference numerals, and the reference numerals of some of the same components are omitted in the drawings.

[0054] The utility model relates to a holding base for oral digital impression instrument field, and specifically relates to a charging holding base for the matched handheld piece of wireless oral digital impression instrument.

[0055] Figure 1 A holding base for holding an object having a hand-held portion according to an embodiment of the utility model is shown, the holding base comprising an outer housing, the outer housing comprising an upper housing body 100 and a bottom cover 200, the upper housing body 100 being fixedly fitted to the bottom cover 200, for example by snap fitting, to form an inner space between the upper housing body 100 and the bottom cover 200, i.e. the inner part of the outer housing.

[0056] Referring to Figure 1 and additionally referring to Figures 2-3 The upper housing body 100 comprises a housing body 110 and a top cover 120, which can be mounted on the housing body 110 to form the upper housing body 100. Specifically, the housing body 110 has a through hole 1111 Figure 2The inner edge 111, which is shown as five, is labeled only at one place for clarity, defines a shell body opening 112, and the shell body 110 has a shell body snap portion 113 at its lower portion for assembly of the upper shell body 100 and the bottom cover 200. In embodiments where the holding base has a charging function, an indicating component such as a light guide pillar can also be installed inside the shell body 110 to show the charging status by, for example, a back adhesive.

[0057] Referring to Figure 2 and Figure 4 The top cover 120 has an upper flange 121 that rests on the inner edge 111 of the shell body 110. The upper flange 121 can have protrusions 1211 that are configured to pass through corresponding through holes 1111 and be fixed together with the through holes 1111 by, for example, self-tapping screws or the like fasteners when the top cover 120 is mounted to the shell body 110, such that the upper flange 121 is fixed to the inner edge 211 (visible from Figure 6 The top cover 120 also has a central holding recess 122 for holding an object, which recess 122 extends into the bottom cover 200 when the top cover 120 is mounted to the shell body 110.

[0058] It should be understood that although in the described embodiments the central holding recess 122 is formed separately in the top cover 120, in other embodiments the central holding recess 122 can be formed jointly by the shell body 110 and the top cover 120. Further, as long as the upper shell body 100 has a central holding recess 122 recessed from its upper surface toward the bottom cover 200 for holding an object. It should be understood that "central" is used to describe the position of the recess in the horizontal plane relative to the entire upper shell body 100 rather than relative to the position of the top cover 120.

[0059] Referring to Figures 4-5 In the present embodiment, the top cover 120 can have a top cover opening 123 to expose a charging connector to be described below. The top cover 120 can also have a top cover vent 124 in fluid communication with the interior of the outer shell, which can help dissipate heat inside the outer shell.

[0060] Figure 6A side view cross-section of the holding base is shown. The holding base is assembled from a shell body 110, a top cover 120 and a bottom cover 200, and after the top cover 120 is mounted on the shell body 110, the central holding recess 122 of the top cover 120 is positioned to be recessed towards the bottom cover 200 and inclined by about 5 degrees relative to the vertical direction. It should be understood that the central holding recess 122 can be designed to be inclined by any degree relative to the vertical direction or not inclined at all according to actual application occasions without increasing the size of the holding base. It can be seen from the figure that a part of the hand-held piece 1 is received in the central holding recess 122.

[0061] Figure 7 The bottom cover 200 of the holding base is shown in more detail, which has a bottom cover buckle part 201 for assembly of the upper shell body and the bottom cover 200. The bottom cover 200 also preferably has a fixed connection part (not shown) provided in the lower surface of the bottom cover 200, which can be a groove provided with a copper nut, for example, which is open towards the lower surface of the bottom cover, and can be fixed to, for example, a bracket by a fixing device such as a screw, so as to conveniently fix the holding base on other objects for use. The positioning parts can be arranged symmetrically at the bottom of the bottom cover 200 to enhance the fixation of the holding base. It is also preferable that the bottom cover 200 has a bottom cover ventilation part 202 in fluid communication with the inside of the outer shell. In combination Figure 6 and Figure 7 It can be seen that the top cover ventilation part 124 is in fluid communication with the bottom cover ventilation part 202 to facilitate heat dissipation in the inside of the outer shell.

[0062] Continuing to refer to Figure 6 and Figure 7 More preferably, the hand-held piece 1 has an air inlet 2 and an air outlet 3 at the bottom thereof, when the hand-held piece 1 is held by the holding base, the air inlet 2 is at least partially aligned with the top cover ventilation part 124, so that air can enter the inside of the hand-held piece 1 from the external environment via the bottom cover ventilation part 202, the top cover ventilation part 124 and the air inlet 2, and the air outlet 3 is at least partially aligned with the top cover ventilation part, so that air can pass from the inside of the hand-held piece 1 to the external environment via the air outlet 3, the top cover ventilation part and the bottom cover ventilation part 202. Through the cooperation of the air inlets 2 and air outlets 3 with the ventilation parts corresponding to the holding base, heat dissipation of the hand-held piece is facilitated. It should be noted that the central holding recess 122 of the hand-held piece 1 and the holding base can not be a completely sealed fit, so the air inlets and outlets for heat dissipation will not completely travel from the top cover ventilation part 124 or the bottom cover ventilation part 202. For example, as Figure 6 shown, the central holding recess 122 can be slightly expanded upwards, so that the air inlets and outlets for heat dissipation will also travel in the gap between the hand-held piece 1 and the top cover 120.

[0063] In additional embodiments, a liquid discharge channel can be formed inside the outer housing that communicates the top cover vent 124 with at least a portion of the bottom cover vent 202 and is laterally sealed, i.e., the path from the top cover vent 124 to the bottom cover vent 202 via the liquid discharge channel is sealed so that liquid does not side leak to other spaces inside the outer housing. The liquid discharge channel can reduce liquid accumulation that can fall from the handpiece to the central retaining recess of the holding base.

[0064] In embodiments of the present application, the bottom cover further has a support portion 203 configured to support the central retaining recess 122. The above-mentioned bottom cover vent 202 can also optionally be arranged around the support portion 203. The support portion 203 can on one hand provide some support to the top cover 120 so that the durability of the handpiece during placement is improved, and on the other hand can provide partial air duct portion isolation so that the air intake and exhaust of the handpiece is more conveniently conducted from the top cover to the bottom cover.

[0065] Referring to Figure 7 and additionally referring to Figures 8-10 , the holding base further comprises a charging flexible circuit board, i.e., a charging FPC board 300, which can be mounted inside the outer housing by screws and back glue and the like fixing members. Specifically, the bottom cover 200 has a plurality of first bosses 204 Figure 7 shown as four first bosses 204) to support and fix a rigid first portion 301 of the charging FPC board 300. A flexible second portion 302 of the charging FPC board 300 is flexibly connected to and extends from the first portion 301. The bottom cover 200 has at least two limit posts 205 to guide the extension path of the second portion 302 and position the second portion 302 on the bottom cover 200. A rigid third portion 303 of the charging FPC board 300 is connected to and extends from the second portion 302 at a substantially middle position of the second portion 302. A charging connector 310 is provided on the third portion 303 of the charging FPC board 300. The third portion 303 also has a limit hole which can be fixed to a charger fixing portion 206 of the bottom cover 200 surrounded by the bottom cover vent 202 and the support portion 203, for example by cooperating with the corresponding limit post on the bottom cover 200. The charging connector 310 is fixed on the third portion 303 and exposed through the top cover opening 123 (see Figure 4 ) of the top cover. A rigid fourth portion 304 of the charging FPC board 300 extends from the second portion 302 and can be bent to cooperate with a counterweight to be described below. The use of the charging FPC board 300 can optimize the circuit layout to help reduce the overall size of the holding base and leave more size for the counterweight below to achieve greater counterweight.

[0066] Note that in the described embodiment, a charging FPC board 300 is used to form the circuit to achieve the charging function of the base. However, the charging FPC board is only one option, and in other embodiments, other electrical components, such as coils and metal elastic sheets, can be used to achieve the charging function.

[0067] Reference Figures 11-12 The base also includes a counterweight 400. In the described embodiment, the counterweight 400 is a single, integral ring-shaped counterweight. However, in other embodiments, the counterweight can be a ring-shaped counterweight composed of multiple counterweight sub-components, or even in another embodiment, the counterweight can be multiple crescent-shaped counterweight blocks surrounding a central retaining recess. In the case where the counterweight 400 is a single, integral ring-shaped counterweight, it is advantageous that the counterweight 400 is cut from a circular steel tube. Compared to existing ring-shaped counterweight blocks, this counterweight 400 does not require a specific shape design based on the internal space shape of the retaining base. After cutting, it only requires minimal processing, such as chamfering, tapping, and drilling, and can be used directly, thus making manufacturing more convenient and reducing costs.

[0068] As shown in the figure, the counterweight 400 is installed inside the housing and fixed to the bottom cover 200, and can extend vertically upward from the bottom cover 200. Specifically, the counterweight 400 is supported by a second boss 207 on the bottom cover 200 and fixed to the second boss 207 by, for example, screws. The second boss 207 can be distributed symmetrically with respect to the horizontal cross-section of the counterweight 400. Figure 7 The base cover 200 is shown as four second protrusions 207 to achieve a uniform weight distribution of the counterweight 400. Preferably, the base cover 200 is also provided with positioning portions 208 configured to position the counterweight 400 relative to the base cover 200 for easy installation of the counterweight 400. The lower portion of the positioning portion 208 may be the groove for mounting the copper nut described above. More preferably, reinforcing features (e.g., reinforcing posts) may be provided around the second protrusions 207, which are also inserted into the openings of the counterweight 400 to increase the horizontal connection strength between the counterweight 400 and the retaining base under mechanical impact. The counterweight 400 is also configured to circumferentially surround the central retaining recess ( Figures 11-12 Not shown in the image, see example. Figure 3 The counterweights are arranged in a substantially centrally symmetrical manner relative to the central recess. The charging connector (which is shielded) on the charging FPC board 300 is also surrounded by counterweights. This shape and arrangement of the counterweights 400 achieves a sufficiently large counterweight and a uniform weight distribution, thereby reducing the possibility of the base tipping over when holding an object.

[0069] In the described embodiment, the counterweight 400 is cut to extend vertically upward from the bottom cover 200 to substantially the same height, but this is merely exemplary and not restrictive. In fact, the counterweight 400 can be cut into different shapes according to different requirements. For example, in Figure 6 In the shown embodiment, the counterweight can be cut to have an L-shaped lateral cross section according to the shape of the space inside the shell. In other embodiments, the counterweight can be cut to have a right-angled trapezoidal lateral cross section. These and other shapes are all covered by the scope of the present application.

[0070] It should also be understood that although the counterweight 400 described in the embodiments of the present application is formed by cutting a round steel pipe, this is also not restrictive. In the case of large quantities, the counterweight of the present application can also be manufactured using processing techniques such as die casting molds.

[0071] Optionally, the counterweight 400 has a receiving portion 401, which enables the fourth portion 304 of the charging FPC board to be bent onto the receiving portion 401 of the counterweight 400 to cooperate and fix with it, thereby achieving the fixation of the remaining portion of the charging FPC board 300 and the counterweight 400 in a smaller internal space.

[0072] In an additional embodiment, the counterweight 400 is also provided with a recess 402, and a magnet 403 is installed in the recess, and correspondingly, the handheld piece is provided with a Hall sensor associated with the magnet 403. When a part of the handheld piece enters or exits the central holding recess, the positional relationship between the handheld piece and the counterweight 400 can be sensed by the positional change between the Hall sensor and the magnet, and it can be determined whether a part of the handheld piece has been in the central holding recess, i.e. whether the handheld piece is held by the holding base.

[0073] Compared with the existing charging base, the counterweight processed from a round steel pipe meets the technical effect of a small size and a large counterweight of a charging base specially used for vertically holding a handheld piece.

[0074] Although the structure of the present application has been described above in combination with the preferred embodiments, those skilled in the art should recognize that the above examples are only used for illustration and cannot be regarded as a limitation of the present application. Therefore, the present application can be modified and varied, and these modifications and variations will all fall within the scope defined by the appended claims.

Claims

1. A holding base for holding a handpiece (1) of an intraoral digital impression device, the holding base comprising an outer housing including an upper housing body (100) and a bottom cover (200), the upper housing body (100) being fixedly fitted onto the bottom cover (200), the upper housing body (100) having a central holding recess (122) recessed from an upper surface thereof towards the bottom cover (200), characterized in that the holding base further comprising a counterweight (400) fixed on the bottom cover (200) inside the outer housing and extending vertically upward from the bottom cover (200), wherein the counterweight (400) is disposed to circumferentially surround the central holding recess (122) to be substantially centrally symmetrically distributed with respect to the central holding recess (122).

2. The holding base of claim 1, wherein the counterweight (400) is integrally formed as a ring-shaped counterweight.

3. The holding base of claim 2, wherein the counterweight (400) is cut from a circular steel tube.

4. The holding base of claim 1, wherein the counterweight (400) extends vertically upward from the bottom cover (200) to substantially the same height.

5. The holding base of claim 1, further comprising a charging FPC board (300) mounted inside the outer housing, wherein a charging connector (310) is disposed on the charging FPC board (300) and surrounded by the counterweight (400).

6. The holding base of claim 5, wherein the counterweight (400) has a receiving portion (401), the charging FPC board (300) is bendable such that a portion of the charging FPC board (300) is fitted and fixed with the receiving portion (401) of the counterweight (400).

7. The holding base of claim 1, wherein the bottom cover (200) has a positioning portion (208) configured to position the counterweight (400) with respect to the bottom cover (200).

8. The holding base of claim 5, wherein the upper housing body (100) includes a housing body (110) and a top cover (120) mounted on the housing body (110) to form the central holding recess (122) recessed towards the bottom cover (200), wherein the top cover (120) has a top cover opening (123) to expose the charging connector (310).

9. The holding base of claim 8, wherein the top cover (120) has a top cover vent portion (124) in fluid communication with an inside of the outer housing, and the bottom cover (200) has a bottom cover vent portion (202) in fluid communication with the inside of the outer housing, wherein the top cover vent portion (124) is in fluid communication with the bottom cover vent portion (202). ​ 10. The holding base of claim 9, characterized in that the handpiece (1) has an air inlet (2) which, when the handpiece is held by the holding base, is at least partially aligned with the top cover vent (124) so that air can enter the handpiece (1) interior from the external environment via the bottom cover vent (202), the top cover vent (124) and the air inlet (2), and / or the handpiece (1) has an air outlet (3) which, when the handpiece is held by the holding base, is at least partially aligned with the top cover vent (124) so that air can pass from the handpiece (1) interior to the external environment via the air outlet (3), the top cover vent (124) and the bottom cover vent (202).

11. The holding base of claim 9, characterized in that a liquid discharge channel is formed inside the outer housing, the liquid discharge channel communicating the top cover vent (124) with at least a portion of the bottom cover vent (202) and being laterally sealed.

12. The holding base of claim 1, characterized in that the bottom cover (200) has a support portion (203) configured to support the central holding recess (122).

13. The holding base of claim 1, characterized in that the counterweight (400) is provided with a recess (402) and a magnet (403) is mounted in the recess (402), and wherein the handpiece (1) is mounted with a Hall sensor associated with the magnet (403).

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