Electric toothbrush with optimized mechanical design

Abstract

The present invention relates to an electric toothbrush comprising a brushing roller (4) and a drive shaft having a first end fixed to said brushing roller (4), said toothbrush comprising a first casing (30) through which said drive shaft extends and a cover (8) having an inner surface facing said brushing roller (4) and made of a first material, said drive shaft comprising an end segment projecting outside said first casing (30) and including said first end, said brush comprising a bearing receiving said end segment, said electric toothbrush comprising a protective piece (9) made of a second material softer than said first material, said protective piece (9) covering said inner surface and forming a peripheral lip (90) projecting from the latter, said protective piece (9) forming said bearing.

Description

[Technical field]

[0001] The present invention relates to the general technical field of oral hygiene appliances, and more specifically to the field of toothbrushes, especially for human use.

[0002] The invention more particularly relates to an electric toothbrush comprising an electric motor, a roller for brushing the teeth, and a drive shaft extending longitudinally between a first end fixed to said brushing roller and a second end connected to said electric motor for rotating said brushing roller along said drive shaft and through said drive shaft, said brushing roller extending longitudinally between a proximal end attached to said drive shaft and a free distal end, said toothbrush further comprising a first casing inside which said drive shaft passes, and a cover made of a first material extending longitudinally of said first casing and extending along said brushing roller between a rear end fixed to said first casing and a free front end, said cover having an inner surface facing said brushing roller and an opposite outer surface, said drive shaft comprising an end segment protruding outside said first casing and including said first end, and said toothbrush comprising a bearing fixed to said first casing and receiving said end segment in order to guide said end segment. [Background technology]

[0003] Electric toothbrushes are known which implement motorized brushing elements. These electric toothbrushes are generally satisfying since they allow effective brushing under conditions which are particularly comfortable for the user, since the implementation of motorization makes it possible to reduce the gestures to be performed.

[0004] Nevertheless, these known electric toothbrushes suffer from serious drawbacks.

[0005] In particular, known electric toothbrushes generally have designs that prioritize brushing efficiency primarily, sometimes to the detriment of tissue (including gum) comfort and protection, and thus, known electric toothbrushes may cause at least some discomfort, and even bruising and pain.

[0006] These known electric toothbrushes also do not make it possible to provide an optimal brushing experience, and their mechanical design is the source of durability and reliability problems. Summary of the Invention [Problem to be solved by the invention]

[0007] The object assigned to the present invention is therefore to remedy the drawbacks disclosed above and to propose a new electric toothbrush that, while having a compact and economical construction, allows to carry out a particularly effective and atraumatic brushing, whilst offering remarkable comfort and safety of use.

[0008] Another object of the invention is to propose a new electric toothbrush, the design of which allows precise brushing and optimal comfort.

[0009] Another object of the present invention is to propose a new electric toothbrush whose design allows for fast, simple and economical manufacture.

[0010] Another object of the invention is to propose a new, particularly robust and lightweight electric toothbrush.

[0011] Another object of the invention is to propose a new electric toothbrush of particularly durable construction.

[0012] Another object of the invention is to propose a new electric toothbrush, the design of which allows for optimized industrial manufacturing.

[0013] Another object of the invention is to propose a new electric toothbrush, the design of which makes it possible to limit parasitic vibrations and improve the lifespan of the components forming the toothbrush. [Means for solving the problem]

[0014] The object assigned to the present invention is achieved by using an electric toothbrush comprising an electric motor, a roller for brushing the teeth, and a drive shaft extending longitudinally between a first end fixed to said brushing roller and a second end connected to said electric motor for rotating said brushing roller along a first axis of rotation through said drive shaft, said brushing roller extending longitudinally between a proximal end attached to said drive shaft and a free distal end, said toothbrush comprising a first casing through which said drive shaft extends, and a brushing roller extending longitudinally through said first casing between a rear end fixed to said first casing and a free front end, and a cover made of a first material extending along the brushing roller, the cover having an inner surface arranged facing the brushing roller and an opposite outer surface, the drive shaft including an end segment protruding outside the first casing and including the first end, the toothbrush comprising a bearing fixed to the first casing and receiving and guiding the end segment, the electric toothbrush comprising a protective piece made of a second material softer than the first material, the protective piece covering the inner surface and protruding from the latter to form a peripheral lip surrounding the cover, the protective piece including a ring locally surrounding the end segment to form the bearing. [Brief description of the drawings]

[0015] Other particularities and advantages of the invention will appear in more detail on reading the following detailed description, given purely by way of illustrative and non-limiting example, with reference to the attached drawings, in which: [Figure 1] FIG. 1 shows a schematic front view of an electric toothbrush according to the present invention. [Diagram 2]FIG. 2 shows, in a schematic perspective view, a structural detail of the electric toothbrush of FIG. 1 that is part of the removable brushing head. [Diagram 3] FIG. 3 is a schematic perspective view showing construction details of the electric toothbrush of the previous figures in a three-quarter rear view. [Figure 4] FIG. 4 is a schematic perspective view showing, in a three-quarters front elevation, details of the construction of the electric brush of the previous figure, with the brushing roller omitted. [Diagram 5] FIG. 5 shows, in a schematic perspective view, a protective piece for the toothbrush of the previous figures, which protective piece is in this case made of a soft plastic material and which is intended in this case to completely cover the inside of the cover of the toothbrush. [Figure 6] FIG. 6 shows the same structural details as shown in FIG. 4, with the difference that the protective strip has also been omitted to make it possible to see the inner surface of the cover. [Figure 7] FIG. 7 shows, in a schematic view of a longitudinal section, a detail of the construction of the electric toothbrush of the previous figures, with a brushing roller represented diagrammatically by a cylinder. [Figure 8] FIG. 8 shows, in a schematic perspective view, a structural detail of the electric toothbrush of the previous figures, which is part of a body intended to be removably associated with a brushing head comprising the structural detail shown in FIG. [Figure 9] FIG. 9 shows, in a schematic perspective view, a brushing head including the structural details shown in FIG. 2 forming part thereof, said brushing head being intended to be joined to a body, the details of which are shown in FIG. 8, the brush roll being omitted. [Figure 10] FIG. 10 shows, in a schematic view of a longitudinal section, the brushing head of the toothbrush of the previous figure. [Figure 11] FIG. 11 shows, in a schematic view of a longitudinal section, a detail of the construction of the brushing head of FIG. 10, with the subassembly formed by the brushing roller and the receiving segment of the drive shaft omitted. [Figure 12]FIG. 12 shows, in a schematic view of a longitudinal section, the subassembly formed by the brushing roller and the receiving segment of the drive shaft, which is omitted in FIG. [Figure 13] FIG. 13 shows, in a schematic perspective view, details of the construction of the toothbrush of the previous figure, corresponding to the latter's kinematic chain including the electric motor, the drive shaft (including universal joints) and the brushing rollers, the latter being represented in this case diagrammatically by a cylinder. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] It should be noted in advance that the terms "first", "second", "primary", "secondary", etc., used herein do not necessarily have any connotation of order or cardinality, i.e., no notion of order, quantity or any classification of the elements or components to which these terms are attached is implied herein. In particular, the use of these terms does not necessarily imply the existence of related items of a higher order or rank. In this case, these terms are only intended to facilitate the understanding of the present invention by making it possible to distinguish certain technical features thereof.

[0017] The present invention relates to an electric toothbrush 1 intended to maintain oral hygiene by removing food debris and plaque. The electric toothbrush 1 according to the invention is advantageously intended for humans, but according to alternative embodiments it can be perfectly adapted for veterinary use, for example for domestic or company animals.

[0018] Advantageously, the electric toothbrush 1 comprises a manual gripping member 2, preferably forming a handle intended to be gripped manually by a user, allowing the user to manipulate the electric toothbrush 1, in particular to control its position in space and its orientation, as well as its pressure in contact with the teeth to be brushed. The handle, advantageously forming the manual gripping member 2, extends longitudinally, for example along a central longitudinal axis X-X'. Preferably, the toothbrush 1 comprises a body 20, which advantageously comprises a second casing 20A, in which the different components of the electric toothbrush 1 are preferably intended to be housed, in particular the mechanical, electrical and electronic components. Advantageously, the second casing 20A forms the manual gripping member 2.

[0019] Advantageously, as shown in the figures, the electric toothbrush 1 comprises a brushing head 3, preferably attached to an axial extension of the body 20. Preferably, the brushing head 3 is removably attached to the body 20, for example to allow easy replacement of the head 3 when one or more components of the head 3 become worn out, or alternatively to use a brushing head with different characteristics. Thus, in the preferred embodiment shown in the figures, the electric toothbrush 1 comprises two different and independent mechanical subassemblies corresponding respectively to the brushing head 3 and the body 20, the two subassemblies in question 3, 20 being designed in such a way that they can be mechanically coupled in a removable and reversible manner with a view to forming the electric toothbrush 1, and thus advantageously having a modular character. However, in alternative embodiments, it is possible to permanently fix the brushing head 3 to the body 20, without the possibility of separation.

[0020] The electric toothbrush 1 also comprises a member for brushing the teeth, which is advantageously arranged substantially at one end of the electric toothbrush 1 and therefore preferably has a generally elongated shape extending longitudinally along said central longitudinal axis X-X'. Preferably, the brushing member is part of the brushing head 3. More precisely, as shown in the figure, the brushing member is formed by a roller 4 for brushing the teeth, designed to come into contact with the teeth to ensure cleaning, in this case by the abrasive mechanical action of brushing. To ensure the brushing function assigned to it, the roller 4 for brushing the teeth advantageously comprises brushing projections 5, preferably formed by a plurality of bristles or pins. Said brushing projections 5 are preferably made of a synthetic material and advantageously have substantially soft and flexible characteristics. The roller 4 for brushing the teeth is advantageously mounted to rotate along a first axis of rotation Y-Y', which is advantageously parallel to and preferably coincides with the abovementioned central longitudinal axis XX'. The brushing rollers 4 are therefore designed to rotate, preferably substantially continuously, in the same direction, which direction can be advantageously modified depending on the area of ​​the dentition to be brushed and the position of the electric toothbrush 1 relative to this area. The use of brushing rollers 4 which rotate continuously in one or another direction of rotation is preferred, in order to allow a particularly effective cleaning of the dentition while limiting the risk of trauma. The implementation of oscillating or active brushing members, as provided by the invention, proves to be much less advantageous in terms of the compromise between brushing efficiency and minimization of the risk of trauma than the use of a continuously rotating brushing roller 4.

[0021] The brushing roller 4 comprises a central core 4A, for example as shown in the figures, formed in this case by a substantially elongated core that is substantially coaxial with said first axis of rotation Y-Y'. The brushing projections 5 preferably project radially from said central core 4A. The brushing projections 5, advantageously formed by substantially soft pins or bristles, are distributed helically along the first axis of rotation Y-Y' (as shown in the figures). In other words, in this preferred embodiment, the brushing projections 5 each extend between an inner end connected to the central core 4A and a free outer end, along which they form a spiral or a spiral around said central core 4A. The brushing roller 4 thus advantageously forms a cylindrical brush in the shape of a swab.

[0022] For example, the central core 4A is formed by a metal wire folded into a U and twisted on itself to capture the brushing projections 5 between the arms of said U, said twisting giving a helical distribution to the plurality of brushing projections 5. Thanks to this helical spread, in a spiral around the first axis of rotation Y-Y', the brushing roller 4 is able to provide a gentle brushing that respects the sensitivity of the tissues involved, while being particularly effective in terms of cleaning action. The helical distribution of the brushing projections 5 also makes it possible to facilitate the deformation of the brushing surface formed by the brushing projections 5, thus allowing a significant variation of the bulk volume of the brushing roller 4, thereby allowing the brushing roller 4 to slide into areas of complex and narrow shape, ensuring an effective and atraumatic brushing.

[0023] According to the invention, the electric toothbrush 1 comprises an electric motor 6, advantageously embedded by the body 20, for example housed in the above-mentioned second casing 20A and preferentially forming said manual gripping member 2. The electric motor 6 in question is preferably a direct current motor with a stator, a rotor and an output shaft 6A fixed to the rotor and rotated directly or indirectly (for example via a reduction gear) by the rotor. Said electric motor 6 is intended to be powered by a power supply current, preferably direct current. Said power supply current passes through the motor, causing said stator and rotor to rotate relative to each other. Advantageously, in order to provide said power supply current to the motor 6, but also possibly to other electric or electronic members on the brush 1, the brush comprises an energy source embedded by the body 20. Said energy source is for example formed by at least one rechargeable or non-rechargeable cell or battery, which is preferably housed in the gripping member 2, for example in said second casing 20A.

[0024] According to the invention, the electric toothbrush 1 comprises a drive shaft 7, preferably coaxial with a first axis of rotation Y-Y' (itself advantageously coinciding with a central longitudinal axis X-X') between a first end 7A fixed to said brushing roller 4 and a second end 7B connected to said electric motor 6, and said brushing roller 4 is driven continuously through said drive shaft 7 along said first axis of rotation Y-Y', as mentioned above. For this purpose, the drive shaft 7 is preferably connected towards its second end 7B to an output shaft 6A of the electric motor 6. The output shaft 6A, for example, has a polygonal section (for example a square section) and is inserted into a cavity of corresponding shape arranged at the second end 7B, thus allowing the rotational drive of the drive shaft 7 by the motor 6 along the first axis of rotation Y-Y'. The brushing roller 4 in turn extends longitudinally (i.e. in the direction embodied by the central longitudinal axis X-X') between a proximal end 40, which is attached to the drive shaft 7, for example at a first end 7A of said drive shaft 7, and a distal end 41. Said distal end 41 is free, i.e. is not extended or maintained in particular by a mechanical guide member. The use of a free distal end 41 makes it possible to give the roller 4 for brushing the teeth the ability to move, in particular by facilitating a bending deformation of the central core 4A, which allows the roller 4 for brushing the teeth to deflect, thus facilitating a brushing that is not only effective and precise, but also particularly gentle and atraumatic.

[0025] Preferably, the drive shaft 7 is advantageously open at said first end 7A and comprises a central well into which the terminal portion 40A of the central core 4A projecting axially from the brushing roller 4 is inserted. Preferably, the terminal portion 40A in question is pressed into said well provided at the first end 7A of the drive shaft 7 so as to enable the rotational drive of the central core 4A along the first axis Y-Y' by the drive shaft 7. Optionally, this fixing by friction can be complemented by additional fixing means (for example adhesive). The central core 4A thus advantageously extends in continuity with the drive shaft 7, which is advantageously coaxial with the first axis of rotation Y-Y' as shown in the figure, itself advantageously coinciding with the central longitudinal axis X-X'.

[0026] As shown in the figures, the toothbrush 1 further comprises a first casing 30, in which said drive shaft 7 extends, at least partially. In the embodiment shown in the figures, a first part of the drive shaft 7 extends in the first casing 30 and a second part of said drive shaft 7 extends in the second casing 20A, said first and second parts of the drive shaft 7 being connectable to each other in a removable manner to allow separation of the brushing head 3 and the body 20. However, without departing from the scope of the invention, it is entirely conceivable that the brushing head 3 and the body 20 are not removable, so that the toothbrush 1 has a one-piece character, in this case with a single casing extending over the entire drive shaft 7. The first casing 30 is preferably made of a relatively rigid plastic material, for example a thermoplastic polymer. The thermoplastic polymer in question may be, for example, a styrenic polymer such as acrylonitrile butadiene styrene (ABS), or a polymer of the polyester class such as poly(butylene terephthalate) (PBT), or a composite material formed by example of a thermoplastic polymer matrix filled with glass fibers.

[0027] As shown in the figures, the toothbrush 1 further comprises a cover 8 extending longitudinally through the first casing 30 and along said brushing roller 4 between a rear end 8A fixed to said first casing 30 and a free front end 8B. In other words, the cover 8 extends from the extreme parts of the first casing 30 longitudinally and substantially parallel to the central longitudinal axis X-X' so as to cover a part of the imaginary cylindrical surface on which the brushing roller 4 fits. The cover 8 thus contributes to forming a screen that exposes only a part of the side surface of the brushing roller 4. Preferably, the cover 8 is advantageously formed by a slightly curved tongue so as to follow the profile of the brushing surface defined by the roller 4. The cover 8 thus has a tab shape that preferably extends substantially over the entire length of the roller 4. The cover 8 has, more precisely, an inner surface 80 facing said brushing roller 4, i.e. facing the latter, and an opposite outer surface 81. The cover 8 is advantageously made of a first material, which is for example a relatively rigid plastic material, for example a thermoplastic polymer. The thermoplastic polymer forming said first material may for example be a styrene-based polymer, such as acrylonitrile butadiene styrene (ABS), or a polymer from the polyester family, such as poly(butylene terephthalate) (PBT). However, the cover 8 has substantially flexible properties and can be deformed, for example in bending and possibly in torsion, as accompanied by a corresponding deformation of the roller 4, which again contributes to a particularly effective, precise and atraumatic brushing.

[0028] Advantageously, the cover 8 is integral with the first casing 30. This means that, in this preferred form of relationship shown in the figures, the cover 8 and the first casing 30 are integrally formed by a single part, for example obtained by moulding a plastic material (for example a thermoplastic polymer such as ABS or PBT as mentioned above), the first casing 30 forming a hollow envelope defining the internal housing of the drive shaft 7, said hollow envelope being extended by a spatula-shaped flat part corresponding to the cover 8.

[0029] As shown in the figure, the drive shaft 7 comprises an end segment 70 that emerges outside the first casing 30 and comprises said first end 7A. In other words, the end segment 70 extends partly outside the first casing 30 and partly inside the first casing 30 and protrudes from the first casing 30 such that the first end 7A is located outside the first casing 30. To ensure the guidance of the drive shaft 7 and the maintenance of the roller 4 for brushing the teeth in the correct position, the toothbrush 1 comprises a bearing fixed to the first casing 30 and receiving said end segment 70 to guide it. The bearing thus allows the end segment 70 to be locally maintained in a predetermined position relative to the first casing 30 while allowing the rotation of the drive shaft 7 along the first axis of rotation Y-Y'.

[0030] According to the invention, the electric toothbrush comprises a protective piece 9 made of a second material, which is softer than said first material. Said second material preferably has the properties of elasticity, deformability and softness. The Shore A hardness of the second material is, for example, lower than that of the first material. Preferably, the Shore A hardness value of the second material is between 40 and 80, even more preferably between 50 and 70, particularly preferably about 60. The second material is, for example, an elastomer or a thermoplastic elastomer (TPE), such as polystyrene-b-poly(ethylene-butylene)-b-polystyrene (SEBS) or polystyrene-b-polybutadiene-b-polystyrene (SBS). It is also possible to use, for example, a second silicone-like material.

[0031] The protective piece 9 is therefore advantageously less stiff and more flexible than the cover 8. As shown in the figures, the protective piece 9 covers the inner surface 80 of the cover 8 and projects beyond the cover 8 to form a peripheral lip 90 surrounding said cover 8. In other words, the peripheral lip 90 covers the inner surface 80 and projects laterally from the cover 8, thus forming together with the latter an atraumatic protective guard.

[0032] Said protective guard is intended to prevent tissues of the oral cavity that are not subjected to the action of brushing by the roller 4 from unexpected contact with the brushing roller 4, which may cause discomfort or trauma. In other words, the subassembly formed by the cover 8 and the protective piece 9 plays the role of a spacer that partially covers the lateral surface of the brushing roller 4 in order to protect the mucous membrane adjacent to the teeth, more specifically the cheeks, the lips and even the tongue, from the action of said roller 4. The cover 8 and the protective piece 9 thus contribute to forming a kind of shield that masks the non-functional areas of the brushing roller 4 in order to protect the labial, cervical and lingual mucosa from the abrasive action of the roller 4. The shield in question therefore makes it possible to separate the mucous membrane of the tooth to be brushed, thus providing sufficient space to position the roller 4 in the right position and to allow the latter's rotational movement along the vestibular, palatal and lingual surfaces of the tooth. This technical measure, in other words, makes it possible to obtain, by combining the cover 8 and the protective piece 9, a spacer that is very soft, deformable and atraumatic, yet effectively guarantees the protection of the mucous membrane.

[0033] Furthermore, the protective piece 9 comprises a ring 91 which locally surrounds said end segment 70 to form said bearing.

[0034] The very specific design disclosed above has significant advantages. It makes it possible to benefit both from a bi-material protective guard, capable of minimizing trauma risks and offering great comfort of use, and from a controlled flexibility thanks to the presence of a cover 8 that is more rigid than the protective piece 9. In addition, the use of a ring 91 made of a second material to form the guide bearing of the drive shaft 7 at the outlet of the first casing 30 allows a variation in the angular orientation of said drive shaft 7. Thus, the inclination of the roller 4 for brushing the teeth relative to the central longitudinal axis XX' is facilitated, which is a source of comfort and precision of brushing efficiency. The roller 4 for brushing the teeth and the protective guard formed by the combination of the protective piece 9 and the cover 8 are therefore advantageously capable of deflecting substantially simultaneously, according to different deformation profiles, allowing the end of the brushing head 3 to have an evolving shape that is able to dynamically adapt to the mechanical stresses that affect the brushing head 3 during use. This deformability, in combination with the above-mentioned properties, is optimized thanks to the implementation of a brushing roller 4 whose distal end 41 is free, i.e. not guided.

[0035] In particular, the combined flexibility of the cover 8 and the protective piece 9 allows a significant flexibility of the handle 2 and of the head 3 relative to the central longitudinal axis X-X' associated with the latter, according to a deflection angle (measured between the first axis Y-Y' and the central longitudinal axis X-X') that can reach, for example, approximately 7°.

[0036] Thus, the specific design disclosed above makes it possible to respect the high proprioceptive sensitivity of the dental apparatus and the high sensitivity of the gingival tissue to cutting.

[0037] Furthermore, the presence of the junction between the peripheral lip 90 and the ventral area 92 formed by the protective piece 9 and preferably covering the inner surface 80 substantially completely makes it possible to preserve the tissue during the deflection of the brushing roller 4. Thanks to the covering of the inner surface 80 by the layer of a second material forming said ventral area 92 of the protective piece 9, preferably completely, the brushing projections 5 which may be used to come into contact with the inner surface 80 come to rub against the ventral area 92, the softness, preferably smooth consistency of which preserves the integrity of the projections 5 and limits the deterioration due to abrasion of the latter.

[0038] The specific design adopted therefore makes it possible to avoid contact of the teeth with hard point areas or hard surfaces, which again contributes to the atraumatic and comfortable properties of the brush 1.

[0039] The use of a soft ring 91 to form a bearing may facilitate significant angling of the roller, particularly relative to the cover 8, which may expose the inner surface 80. Covering the inner surface 80 with a soft material may limit the traumatic risk to tissues of the oral cavity from an exposed inner surface due to angling of the roller relative to the cover 8.

[0040] Advantageously, the protective piece 9 comprises a front wall 9A extending in front of said distal end 41 of the roller 4 for brushing teeth, masking the latter to avoid a potentially traumatic contact with the mucous membrane with the front surface of the roller 4 for brushing teeth corresponding to the distal end 41. The brushing roller 4 is thus inserted between the one ring 91 and the other front wall 9A. For example, said front wall 9A comprises a number of pins extending parallel to a plane substantially perpendicular to said first axis of rotation Y-Y', and therefore in this case also perpendicular to said central longitudinal axis X-X'. Said number of pins of the front wall 9A thus form a soft lining in the axial extension of the brushing roller 4, arranged opposite the distal end 41 of the brushing roller 4, substantially transverse to the first axis of rotation Y-Y'. The soft lining formed by the pins in question forms a cover for the brushing roller 4 in the latter a priori non-functional area, making it possible to avoid interference with the mucosa of the non-functional area in question, while having soft properties, thus respecting the tissue and providing a comfortable brushing. Advantageously, the pins forming this soft lining can also be used for brushing. Said pins extend, for example, over two rows, arranged one behind the other, as shown in the figure, thus forming tufts of bristles that not only protect the mucosa of the free front surface of the roller 4, but also make it possible to ensure a brushing function in addition to that provided by the roller 4 for brushing the teeth.

[0041] Advantageously, the protective piece 9 is integrally formed by a single piece including a central body with a footprint 93 intended to receive the cover 8 in a coordinated manner, said central body being provided with a ring 91 at one of its ends and a number of pins forming the front wall 9A at the other end. The single piece forming the protective piece 9 can thus be obtained by moulding a plastic material, for example a silicone, an elastomer or a thermoplastic elastomer (TPE), such as polystyrene-b-poly(ethylene-butylene)-b-polystyrene (SEBS) or polystyrene-b-polybutadiene-b-polystyrene (SBS), as previously mentioned. Advantageously, the protective piece 9 is over-molded on top of the cover 8 and the first casing 30, as shown in the figure. This embodiment is preferred as it allows a simple, fast and economical industrial manufacture. The implementation of the bearing, at least partially formed by a ring 91 surrounding the upper part of the first casing 30 with an orifice provided through the latter and from which said end segment 70 emerges, also facilitates manufacture and, thanks to its deformability, makes it possible to insert the core 4A into the well opening of the first end 7A of the drive shaft 7.

[0042] Advantageously, as shown in the figure, the brushing head 3 embeds said brushing roller 4, a first casing 30, a cover 8 and a protective piece 9. In the preferred embodiment shown in the figure, the drive shaft 7 advantageously comprises a lower.

[0043] a receiving segment 700 embedded by said brushing head 3 and including said first end 7A; A motor segment 701 embedded by the body 20 and including the second end 7B.

[0044] Thus, the receiving segment 700 is advantageously housed in the first casing 30 and the motor segment 701 is advantageously housed in the second casing 20A.

[0045] Advantageously, the receiving segment 700 comprises first mechanical coupling means 700A and the motor segment 701 comprises second mechanical coupling means 700B, intended to cooperate with the first mechanical coupling means 700A when establishing a mechanical drive connection between the receiving segment 700 and the motor segment 701 when the brushing head 3 is placed directly on the body 20 and when attached. More precisely, said first and second mechanical coupling means 700A, 700B are complementary in order to releasably couple said motor segment 701 and the receiving segment in rotation. Preferably, at least one of said first and second mechanical coupling means 700A and 700B forms a female coupling member and the other of said first and second mechanical coupling means 700A and 700B forms a corresponding male coupling member. For example, the first mechanical coupling means 700A is formed by a polygonal coupling footprint provided at the free end of the receiving segment 700 located opposite the first end 7A, while the second mechanical coupling means 700B comprises a corresponding polygonal coupling end piece arranged at the free end of the motor segment 701 located opposite the second end 7B. Said coupling end piece thus forms a multi-sided end piece intended to be inserted in said coupling footprint in order to transmit the rotational movement of the motor segment 701 imparted by the motor 6 to the receiving segment 700.

[0046] Preferably, according to the embodiment shown in the figures, the drive shaft 7 comprises a first shoulder 10, for example arranged such that said end segment 70 extends between said first end 7A and said first shoulder 10. Advantageously, the drive shaft 7 also comprises a second shoulder 11, which is preferably arranged between the first shoulder 10 and the first mechanical coupling means 701. Advantageously, the receiving segment 700 thus comprises said first and second shoulders 10, 11, the latter being in particular capable of holding the receiving segment 700 in place within the first casing 30 of the head 3, as will become clear from the following description. Advantageously, as shown in the figures, said first and second shoulders 10, 11 are arranged facing each other, i.e. they define respective support surfaces facing each other. Said first and second shoulders 10,11 are further spaced apart from one another such that the drive shaft 7 comprises an intermediate segment 71 extending between said first and second shoulders 10,11.

[0047] Advantageously, said first casing 30 extends a receiving segment 700 which advantageously carries the first and second shoulders 10, 11 and includes within it an elongated cavity 30A defined by a cavity wall 30B. The latter preferably has a shape which is substantially rotated along a central longitudinal axis X-X' and its cross section varies in the longitudinal direction (i.e. along the central longitudinal axis X-X') so as to form first and second axial stops 300, 301 for said first and second shoulders 10, 11, respectively. The cavity wall 30B thus has different portions of different sections, the first and second axial stops 300, 301 being formed by notches at the interface between two adjacent portions of the different sections. Thus, the first shoulder 10 is intended to rest on and abut against the first axial stop 300, while the second shoulder 11 is intended to rest on and abut against the second axial stop 301, thereby making it possible to block the axial position of the drive shaft in the first casing 30. Preferably, each of said first and second shoulders 10, 11 forms a respective stop surface extending in a respective plane substantially perpendicular to the central longitudinal axis X-X'. Similarly, the first axial stop 300 and the second axial stop 301 are advantageously formed by flat annular surfaces each extending in a respective plane substantially perpendicular to the central longitudinal axis X-X'. This design, which implements two planes / planar stops facing each other, makes it possible to block the shaft 7, and more precisely the receiving segment 700, at a given axial position in the first casing 30 with precise control of the clearances related to the positioning of the drive shaft 7 in said first casing 30.

[0048] In order to obtain a precise and robust mechanical attachment as well as to facilitate manufacture, the drive shaft 7 preferably comprises first and second different elements 72, 73 which are assembled together and form said first and second shoulders 10, 11, respectively. Preferably, said first and second elements 72, 73 form part of a receiving segment 700, which forms the latter when they are assembled together. The first element 72 forms, for example, an end segment 70 and an intermediate segment 71. Preferably, the first and second elements 72, 73 are assembled together by mating, i.e. by pressing a female element into a male element. The second element 73 comprises, for example, an assembly sleeve 730 which extends longitudinally between a primary end and a secondary end and which opens at said primary end. Said assembly sleeve 730 receives an assembly end piece 720 which is part of said first element 72 and which extends, for example, through said intermediate segment 71. Thus, said assembly end piece 720 is press-fitted into said sleeve 730 of the second element 730 to ensure the mutual fixation of said first and second elements 72, 73. Advantageously, the second element 73 forms at its said second end said first mechanical coupling means 700A, for example in the form of a hexagonal footprint opening at said second end. Preferably, said joint is based on the Morse cone principle, i.e. the assembly end piece 720 located in the axial extension of the intermediate segment 71 has a substantially conical shape with a low inclination, the wall of the assembly sleeve 730 arranged at the first end of the second element 730 also has a conical shape with a low inclination, said conical end piece 720 being mounted in a conical cavity of the sleeve 730, which not only allows a simple and effective fixation of the first and second elements 72, 73 to one another, but also ensures an excellent relative centering of the latter.

[0049] Advantageously, the intermediate segment 71 means that at a distance from said cavity wall 30B, i.e. between the cavity wall 30B and the drive shaft 7, there is a gap J0 over at least a part of the length of the latter. Thanks to the presence of this empty space between the intermediate segment 71 and the cavity wall 30B, the drive shaft 7 is able to bend and / or tilt relative to the central longitudinal axis X-X' during operation, which, in combination with the soft properties of the ring 91 forming the bearing, makes it possible to endow the roller 4 for brushing the teeth with particularly atraumatic properties and the ability to geometrically adapt to the anatomical shapes interfering during brushing.

[0050] The design described above therefore not only ensures a particularly reliable and precise axial stop of the drive shaft 7, thanks to the first and second shoulders 10, 11, but also makes it possible to provide said shaft 7 with the ability to move laterally, locally relative to the central longitudinal axis X-X', which provides for great comfort of use and remarkable brushing efficiency.

[0051] Advantageously, the first axial stop 300 is arranged substantially adjacent to said bearing and thus to the ring 91, and said intermediate segment 71 advantageously comprises a first portion 710 adjacent to said first shoulder 10 and having a conical shape with a cross section decreasing from the first shoulder 10 towards the second shoulder 11 between a maximum and a minimum cross section. The presence of the first conical portion 710 close to the bearing makes it possible to self-center the drive shaft 7 while allowing deformations and temporary tilting of the latter, thanks to a clearance J0 that increases along the first portion 710 in the direction of the second shoulder 11.

[0052] Advantageously, the intermediate segment 71 then comprises a second portion 711, substantially adjacent to said first portion 710 and having, for example, a substantially cylindrical shape whose cross section is equal to or smaller than said minimum cross section. Preferably, the cross section of the second portion 711 is smaller than the minimum cross section in question, the second portion 711 being separated from the first portion 710 by a chamfer 712. Thanks to these geometrical characteristics, the first element 72 is easy and quick to attach and assemble to the second element 73.

[0053] The second element 73 then has a substantially rotating shape with two different sections. The portion of the second element 73 forming the aforementioned assembly sleeve 730 thus has a first cross section dimensioned to leave a gap J1 between the cavity wall 30B and the portion of the second element 73 associated with it, which limits friction, facilitates mounting and promotes bending and / or tilting of the drive shaft 7. The second element 73 also comprises a second portion 731 having a cross section larger than that of the aforementioned first portion. This second portion 731 incorporates the first mechanical coupling means 700A, as previously described. The cross section of the second cylindrical portion 731 is adjusted to the cross section of the cavity 30A so as to locally maintain the drive shaft 7 coaxial with the central longitudinal axis X-X'.

[0054] Thus, in the particular design shown in the figures and described above, the drive shaft 7 is maintained about the central longitudinal axis X-X' only in two spaced apart areas corresponding respectively to the end segment 70 and to the second portion 731 of the second element 73, the drive shaft 7 being located everywhere else away from the cavity wall 30B of the first casing 30. This particular design not only allows for precise control of the clearances associated with the positioning of the shaft 7 within the first casing 30, as previously mentioned, but also allows for variations in the movement of the drive shaft 7 that make it possible to obtain a particularly effective and atraumatic brushing.

[0055] In order to reduce parasitic vibrations likely to be induced by potential misalignment of mechanical components due to manufacturing tolerances of the latter, the drive shaft 7 comprises a first segment 80 and a second segment 81 as well as a universal joint 12 for connecting said first and second segments 80, 81. The first segment 80 preferably comprises said second end 7B as well as a means for mechanically coupling to the output shaft 6A, formed by a footprint arranged at said second end 7B. The first segment 80 comprises the male part of said universal joint 12, which itself comprises a projecting substantially spherical convexity 80A as well as lugs 80B, 80C extending laterally, perpendicular to the central longitudinal axis X-X'. The second segment 81 advantageously comprises in turn the aforementioned motor segment 701. In this case, said motor segment 701 comprises a spherical curved concave portion 81A corresponding to the shape of the spherical convexity 80A of the first segment 80. Said spherical convexity 80A and spherical curved recess 81A are in sliding contact with each other to form a ball joint. Advantageously, said spherical curved recess 81A is extended by a cylindrical cap into which is inserted the top of the first segment 80 carrying said spherical convexity 80A and said lugs 80B, 80C. Said cylindrical cap advantageously comprises two guide slots that accommodate the lugs 80B, 80C to allow relative axial sliding of the first and second segments 80, 81 but lock them in rotation along the first axis of rotation Y-Y'. The universal joint 12 thus forms a spherical finger connection, making it possible to compensate for potential misalignments between the motor segment 701 and the receiving segment 700. Preferably, the guide lugs 80B, 80C that allow the transmission of the rotational movement imparted by the motor 6 extend along a transverse axis passing through the center of a sphere that fits the surface of the spherical convexity 80A. A universal joint 12 conforming to the preceding description therefore makes it possible to benefit from a rigid stop ensuring the positioning of the assembly whilst retaining the possibility of pivoting about a conical first axis of rotation Y-Y', the upper half angle of which is advantageously greater than or equal to 5°.The implementation of the universal joint 12 in particular makes it possible to avoid operation under stress and thus improves the service life of the mechanical components involved whilst improving the comfort of use by reducing parasitic vibrations that may be caused by potential misalignments, as mentioned above.

[0056] Additionally, the second segment 81 advantageously includes a second mechanical coupling means 700B at its end opposite the universal joint 12. As previously mentioned, the second mechanical coupling means 700B advantageously includes a multi-sided end piece, which is advantageously extended by a cylindrical guide head 700C that facilitates centering of the terminal portion of the motor segment 701 and insertion into the terminal portion of the receiving segment 700.

[0057] Advantageously, the toothbrush 1 comprises a lip seal 13, preferably of revolutionary shape, locally surrounding the motor segment 701, and in this case the second segment 81, adjacent to an orifice provided in the second casing 20A and from which the second mechanical coupling means 700B emerge. Said seal 13 advantageously has shoulders facing each other in order to maintain the seal 13 axially in a defined position within the second casing 20A, ensuring the latter sealing, including during rotation of the drive shaft 7 and regardless of the rotational speed performed.

[0058] The rotation speed of the brushing roller 4 can advantageously be controlled by a suitable control interface, for example arranged on the second casing 20A. The control interface in question comprises, for example, a button 200 making it possible to increase the rotation speed and a button 201 making it possible to decrease it instead. The control interface is of course advantageously connected to the motor 6 via a control device, for example comprising an electronic card, which is preferably embedded in the second casing 20A. Advantageously, the brush 1 can comprise a screen 203, for example displaying the duration of brushing and / or the level of the rotation speed of the roller 4. Advantageously, the control interface also comprises an on / off button 202, associated with an electric switch, making it possible to turn the brush 1 on or off.

[0059] Preferably, said cover 8 and protective piece 9 form a monolithic subassembly that occupies a rest position (shown in the figures) in the absence of mechanical stress applied to it, said monolithic subassembly 8, 9 extending longitudinally in a direction of extension substantially parallel to said first axis of rotation Y-Y'. Thanks to the combination of materials from which it is made, said monolithic subassembly has a significant flexibility, thus making it possible to limit or even completely avoid traumatic contact with tissues (teeth and gums). Preferably, said monolithic subassembly thus designed is designed as follows:

[0060] bend elastically relative to said first casing 30 and, in response to a first bending stress acting thereon, reach a first position of maximum elastic bending in which said free front end 8B deviates from said first axis of rotation Y-Y' and such that said direction of extension forms with said first axis of rotation Y-Y' a first angle between 3 and 10°, preferably substantially equal to 5°; and / or In response to a second bending stress in the opposite direction to the first bending stress, it elastically bends relative to the first casing 30 and reaches a second position of maximum elastic bending where the free front end 8B approaches the first axis of rotation Y-Y' and where the extension direction forms a second angle with the first axis of rotation Y-Y', the second angle being between 1 and 4°, preferably substantially equal to 2°.

[0061] Finally, the invention presents a design that facilitates geometric variability of the brushing head 3 as a function of the mechanical stresses to which it is subjected during use, whilst maintaining a very reliable operation and preserving the life of the associated mechanical components. The brush 1 according to the invention thus makes it possible to benefit from a particularly effective and atraumatic brushing, whilst being of robust, lightweight and durable design. [Industrial Applicability]

[0062] The present invention finds its industrial application in the design, manufacture, and use of power toothbrushes.

Claims

1. An electric toothbrush (1) comprising an electric motor (6), a roller (4) for brushing teeth, and a drive shaft (7) extending longitudinally between a first end (7A) fixed to said brushing roller (4) and a second end (7B) connected to said electric motor (6) for rotating said brushing roller (4) through said drive shaft (7) along a first rotation axis (Y-Y'), said brushing roller (4) extends longitudinally between a proximal end (40) attached to said drive shaft (7) and a free distal end (41); The toothbrush (1) further comprises a first casing (30) through which the drive shaft (7) extends, and a cover (8) made of a first material extending longitudinally through the first casing (30) and along the brushing roller (4) between a rear end (8A) fixed to the first casing (30) and a free front end (8B), The cover (8) has an inner surface (80) arranged facing the brushing roller (4) and an opposite outer surface (81); The drive shaft (7) includes an end segment (70) that projects outside the first casing (30) and includes the first end (7A), The toothbrush (1) comprises a bearing fixed to the first casing (30) and adapted to receive and guide the end segment (70); said electric toothbrush (1) comprises a protective piece (9) made of a second material softer than said first material, said protective piece (9) covering said inner surface (80) and projecting from said latter to form a peripheral lip (90) surrounding said cover (8), said protective piece (9) including a ring (91) locally surrounding said end segment (70) to form said bearing; An electric toothbrush (1) characterized by:

2. 2. The electric toothbrush (1) according to claim 1, characterized in that the protective piece (9) includes a front wall (9A) extending in front of the distal end (41), and the brushing roller (4) is inserted between the ring (91) and the other of the front walls (9A).

3. The electric toothbrush (1) according to claim 2, characterized in that the front wall (9A) comprises a number of pins extending parallel to a plane substantially perpendicular to the first axis of rotation (YY').

4. Electric toothbrush (1) according to any one of claims 1 to 3, characterized in that the cover (8) is integral with the first casing (30).

5. An electric toothbrush (1) according to any one of claims 1 to 4, characterized in that the drive shaft (7) comprises a first shoulder (10) and a second shoulder (11) arranged facing each other and at a distance from each other, and the first casing (30) comprises therein an elongated cavity (30A) defined by a cavity wall (30B), the cross section of which varies in the longitudinal direction so as to form first and second axial stops (300) and (301) for the first and second shoulders (10) and (11), respectively.

6. 6. The electric toothbrush (1) according to claim 5, characterized in that the drive shaft (7) includes an intermediate segment (71) extending between the first shoulder (10) and the second shoulder (11) at a distance from the cavity wall (30B).

7. 7. The electric toothbrush (1) of claim 6, characterized in that the first axial stop (300) is arranged substantially adjacent to the bearing and the intermediate segment (71) includes a first portion (710) adjacent to the first shoulder (10) and having a conical shape with a cross-section decreasing from the first shoulder (10) towards the second shoulder (11) between a maximum cross-section and a minimum cross-section.

8. The electric toothbrush (1) according to claim 7, characterized in that the intermediate segment (71) in turn comprises a second portion (711) substantially adjacent to the first portion (710) and having a substantially cylindrical shape whose cross section is less than or equal to the minimum cross section.

9. The electric toothbrush (1) according to any one of claims 5 to 8, characterized in that the drive shaft (7) comprises a first distinct element (72) and a second distinct element (73) which are assembled together, for example by a fitting, and which form the first shoulder (10) and the second shoulder (11), respectively.

10. The brushing device comprises a main body (20) on one hand and a brushing head (3) removably mounted on the main body (20) on the other hand, the main body forming a manual gripping member (2) and comprising a second casing (20A) in which the electric motor (6) is housed, the brushing head (3) embeds the brushing roller (4), the first casing (30), the cover (8) and the protective piece (9), The drive shaft (7) a receiving segment (700) embedded by said brushing head (3) and including said first end (7A), said receiving segment (700) being provided with first mechanical coupling means (700A); a motor segment (701) embedded by said body (20) and including said second end (7B), said motor segment (701) being provided with second mechanical coupling means (700B); Equipped with The electric toothbrush (1) according to any one of claims 1 to 9, characterized in that the first mechanical coupling means (700A) and the second mechanical coupling means (700B) are complementary for releasably connecting the motor segment (701) and the receiving segment (700) during rotation.

11. Electric toothbrush (1) according to claims 5 and 10, characterized in that the receiving segment (700) comprises the first shoulder (10) and the second shoulder (11).

12. The electric toothbrush (1) according to any one of claims 1 to 11, characterized in that the drive shaft (7) comprises a first segment (80) and a second segment (81), and a universal joint (12) for connecting the first segment (80) and the second segment (81).

13. said cover (8) and said protective piece (9) form an integral subassembly which occupies a rest position in the absence of mechanical stress applied thereto, said integral subassembly extending longitudinally in an extension direction substantially parallel to said first axis of rotation (Y-Y'), said single subassembly comprising: bend elastically relative to said first casing 30 and, in response to a first bending stress acting thereon, reach a first position of maximum elastic bending in which said free front end 8B deviates from said first axis of rotation Y-Y' and said direction of extension forms with said first axis of rotation Y-Y' a first angle between 3 and 10°, preferably substantially equal to 5°; and / or The electric toothbrush (1) according to any one of claims 1 to 12, characterized in that in response to a second bending stress in the opposite direction to the first bending stress, the electric toothbrush (1) is designed to bend elastically relative to the first casing 30, so that the free front end 8B reaches a second position of maximum elastic bending approaching the first axis of rotation Y-Y', and the extension direction forms with the first axis of rotation Y-Y' a second angle between 1 and 4°, preferably substantially equal to 2°.

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