OPTIMIZED MECHANICALLY DESIGNED ELECTRIC TOOTHBRUSH

Abstract

An electric toothbrush with an optimized mechanical design. The invention relates to a toothbrush comprising a brushing roller (4), a drive shaft with a first end integral with said brushing roller (4), said toothbrush comprising a first housing (30) within which said drive shaft extends, and a cover (8), made of a first material, having an inner face facing said roller (4), said drive shaft comprising an end section emerging from said first housing (30) and including said first end, said toothbrush comprising a bearing receiving said end section, said toothbrush comprising a protective piece (9) made of a second material more flexible than said first material, said protective piece (9) covering said inner face and extending beyond it to form a lip (90), said protective piece (9) forming said bearing. Oral hygiene instruments.Figure for the summary: Fig. 3.

Description

Description Title of the invention: ELECTRIC TOOTHBRUSH OPTIMIZED MECHANICAL DESIGN

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

[0002] — The present invention relates more particularly to an electric toothbrush including an electric motor, a toothbrush roller, a shaft training extending longitudinally between a first fixed end said brush roller and a second end connected to said electric motor to rotate said brush roller by means of said shaft drive along a first axis of rotation, said brush roller extending longitudinally between a proximal end attached to said drive shaft and a free distal end, said toothbrush further comprising a first housing within which extends said drive shaft, as well as a hood, made of a first material, which extends longitudinally said first casing and extends the along said brush roller between a rear end fixed to the first housing and a free front end, said hood having an inner face situated opposite said brush roller and an opposite outer face, said drive shaft including an extreme section emerging from said first casing and which includes said first end, said toothbrush comprising a bearing which is integral said first housing and receives said extreme section to guide it.

[0003] — Electric toothbrushes using a brushing mechanism are known motorized. These electric toothbrushes are generally satisfactory because they allow for effective brushing, in particularly comfortable conditions for the user, since the implementation of a motorization makes it possible to reduce the gestures to perform.

[0004] — These well-known electric toothbrushes nevertheless have some drawbacks serious.

[0005] — In particular, known electric toothbrushes generally have a design that prioritizes brushing efficiency above all else, sometimes at the expense of Comfort and tissue protection (including gums). Electric toothbrushes known to exist are therefore likely to cause at least discomfort, or even death. pain and aches.

[0006] These known electric toothbrushes do not, moreover, provide a optimal brushing and their mechanical design are a source of durability problems and reliability. The objects assigned to the invention therefore aim to remedy the disadvantages set out above and to propose a new electric toothbrush which, while being compact and economical in construction, provides remarkable comfort and safety of use, while allowing for particularly effective and atraumatic brushing. Another object of the invention aims to provide a new electric toothbrush whose design allows for precise brushing and optimal comfort. Another object of the invention aims to provide a new electric toothbrush whose design allows for rapid, simple and economical manufacturing. Another object of the invention aims to provide a new electric toothbrush that is particularly robust and lightweight. Another object of the invention aims to provide a new electric toothbrush of particularly durable construction. Another object of the invention aims to propose a new electric toothbrush whose design allows for optimized industrial manufacturing. Another object of the invention aims to provide a new electric toothbrush whose design limits unwanted vibrations and improves the lifespan of the components that make up the toothbrush. The objects assigned to the invention are achieved with the aid of an electric toothbrush comprising an electric motor, a tooth-brushing roller, 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 via said drive shaft around a first axis of rotation, 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 housing within which said drive shaft extends, as well as a cover, made of a first material, which longitudinally extends said first housing and extends along said brushing roller between a rear end fixed to the first housing and a free front end,said hood having an inner face situated opposite said brush roller and an opposite outer face, said drive shaft comprising an end section emerging from said first housing and including said first end, said toothbrush comprising a bearing which is integral with said first housing and receives said end section to guide it, said electric toothbrush being characterized in that it comprises a protective piece made of a second material more flexible than said first material, said protective piece covering said inner face and extending beyond it to form a , peripheral lip surrounding said hood, said protective part including a ring locally surrounding said extremity section to form said bearing. Other features and advantages of the invention will become apparent in more detail upon reading the following detailed description, with reference to the attached drawings, given by way of purely illustrative and non-limiting examples, in which: [Fig.1] illustrates, according to a schematic front elevation view, an electric toothbrush according to the invention. [Fig.2] illustrates, according to a schematic perspective view, a detail of the realization of the electric toothbrush of [Fig.1], which is part of a removable brushing head. [Fig.3] is a schematic perspective figure which illustrates, from a three-quarter rear elevation view, a detail of the construction of the electric toothbrush from the previous figures. [Fig.4] is a schematic perspective figure which illustrates, from a three-quarter front elevation view, a detail of the realization of the electric brush of the previous figures, where the brush roller has been omitted. [Fig.5] illustrates, according to a schematic perspective view, the protective part of the toothbrush of the previous figures, which protective part is made in this case of flexible plastic material and is intended to cover, in this case entirely, the inner face of the toothbrush cover. [Fig.6] illustrates the same detail of execution as that illustrated by [Fig.4], with the difference that the protective piece has also been omitted to allow visualization of the inner face of the hood. [Fig.7] illustrates, according to a schematic longitudinal section view, a detail of the realization of the electric toothbrush of the previous figures, with the brushing roller represented schematically by a cylinder. [Fig.8] illustrates, according to a schematic perspective view, a detail of the realization of the electric toothbrush of the previous figures, which is part of a main body intended to be removably coupled with the brushing head of which the realization detail illustrated by [Fig.2] is part. [Fig.9] illustrates, according to a schematic perspective view, the brush head of which the manufacturing detail illustrated by [Fig.2] is a part, said brush head being intended to be coupled to the main body of which a detail is illustrated by [Fig.8], the brush roller being omitted. [Fig.10] illustrates, according to a schematic longitudinal section view, the brush head of the toothbrush in the previous figures. [Fig. 11] illustrates, in a schematic longitudinal sectional view, a detail of the construction of the brush head of [Fig. 10], where a sub-assembly formed by the roller brushing and a receiving section of the drive shaft is omitted. [Fig.12] illustrates, according to a schematic longitudinal section view, the subassembly formed by the brush roller and the receiving section of the drive shaft which is omitted on [Fig.11]. [Fig.13] illustrates, according to a schematic perspective view, a detail of the construction of the toothbrush in the previous figures, which corresponds to the kinematic chain of the latter, which includes the electric motor, the drive shaft (including a cardan joint) and the brush roller, the latter being represented schematically in this case by a cylinder. It should be noted beforehand that the terms "first," "second," "primary," "secondary," etc., used in this description do not necessarily have an ordinal or cardinal connotation; that is, they do not imply any notion of order, quantity, or any categorization of the elements or components to which these terms are attached. In particular, the use of these terms does not necessarily imply the existence of associated items of a higher order or rank. In this case, these terms are intended solely to facilitate understanding of the invention by allowing for the differentiation of certain technical characteristics. The invention relates to an electric toothbrush 1, intended for maintaining oral hygiene by removing food debris and dental plaque. The electric toothbrush 1 according to the invention is advantageously intended for human use, but, according to an alternative embodiment, it can be perfectly adapted for veterinary use, for example, for livestock or companion animals. Advantageously, the electric toothbrush includes a hand grip 2, which preferably forms a handle, intended to be grasped manually by a user, enabling the user to manipulate the electric toothbrush 1 and, in particular, to control its position and orientation in space, as well as its pressure in contact with the teeth to be brushed. The handle, which advantageously forms the hand grip 2, extends, for example, longitudinally along a central longitudinal axis X-X'. Preferably, the toothbrush 1 includes a main body 20, which advantageously includes a second housing 20A in which various components are preferably intended to be housed, and in particular, mechanical, electrical, and electronic components of the electric toothbrush 1. Advantageously, the second housing 20A forms the hand grip 2. Advantageously, and as illustrated in the figures, the electric toothbrush 1 comprises a brush head 3 which is preferably mounted on the main body 20, in its axial extension. Preferably, the brush head 3 is mounted removably on the main body 20, to allow easy replacement of the brush head 3, for example when one or more of its components are worn, or to use alternatively brush heads with different characteristics. Thus, in the preferred embodiment illustrated in the figures, the electric toothbrush 1 comprises two distinct and independent mechanical sub-assemblies, corresponding respectively to the brush head 3 and the main body 20, said two sub-assemblies 3 and 20 being designed to be mechanically coupled in a removable and reversible manner to form the electric toothbrush 1, which therefore advantageously has a modular character. However, in an alternative embodiment, it is conceivable that the brush head 3 is permanently fixed to the main body 20, without the possibility of separation. The electric toothbrush 1 also includes a tooth-brushing element, which is advantageously located substantially at one end of the electric toothbrush 1, which thus preferably has a generally elongated shape extending longitudinally along said central longitudinal axis XX. Preferably, the brushing element is part of the brushing head 3. More specifically, as illustrated in the figures, the brushing element is formed by a tooth-brushing roller 4, which is designed to come into contact with the teeth in order to clean them, in this case by an abrasive mechanical brushing action. In order to perform its brushing function, the tooth-brushing roller 4 is advantageously provided with brushing protrusions 5, preferably formed by a plurality of bristles or bristles.The brushing protrusions 5 are preferably made of synthetic material and advantageously have a substantially flexible character. The tooth-brushing roller 4 is advantageously mounted to rotate about a first axis of rotation YY”, which is advantageously parallel to, and preferably coincident with, the aforementioned central longitudinal axis XX”. The brushing roller 4 is thus designed to rotate, preferably substantially continuously, in the same direction, which direction can advantageously be changed depending on the area of ​​the teeth to be brushed and the positioning of the electric toothbrush 1 relative to this area. The use of a brushing roller 4 that rotates continuously in one direction or another is preferred, as it allows for particularly effective cleaning of the teeth while limiting the risk of trauma.The implementation of an oscillating-rotating or vibrating brushing device proves to be much less advantageous, in terms of the compromise between brushing efficiency and minimizing the risk of trauma, than the use of a continuously rotating brushing roller 4, as provided for by the invention. The brush roller 4 includes, for example, as illustrated in the figures, a The central core 4A, formed in this case by a substantially elongated core, is substantially coaxial with the first axis of rotation YY. The brushing protrusions 5 preferentially project radially from said central core 4A. Preferably, the brushing protrusions 5, advantageously formed by substantially flexible bristles or hairs, are distributed helically (as illustrated in the figures) along the first axis of rotation Y-Y'. In other words, in this preferred embodiment, each brushing protrusion 5 extends between an inner end connected to the central core 4A and a free outer end, such that they form a helix, or a spiral, around said central core 4A, along its length. The brushing roller 4 thus advantageously forms a cylindrical brush in the shape of a swab. For example, the central core 4A is formed by a U-shaped metal wire twisted upon itself to capture, between the arms of said U, the brush protrusions 5, such that the twisting in question gives the plurality of brush protrusions 5 a helical distribution. Thanks to this helical arrangement, spiraling around the first axis of rotation YY", the brush roller 4 is particularly effective in terms of cleaning action, while also being able to provide gentle brushing that respects the sensitivity of the tissues concerned.The helical distribution of the brush protrusions 5 also facilitates the deformation of the brushing surface formed by the brush protrusions 5, thus allowing a significant variation in the overall volume of the brushing roller 4, thereby enabling the latter to slip into areas of complex and narrow shapes, ensuring brushing that is both effective and atraumatic. According to the invention, the electric toothbrush 1 comprises an electric motor 6, which is advantageously integrated into the main body 20, and is, for example, housed within the aforementioned second casing 20A, which preferably forms the hand grip 2. The electric motor 6 is preferably a DC motor, with a stator, a rotor, and an output shaft 6A integral with the rotor and driven in rotation by the latter, either directly or indirectly (for example, via a reduction device). The electric motor 6 is intended to be powered by a supply current, which is preferably a DC current. The supply current flows through the motor to rotate the stator and rotor.Advantageously, in order to supply said electrical power to the motor 6 and possibly to other electrical or electronic components equipping the brush 1, the latter includes an energy source carried by the main body 20. Said energy source is formed for example by at least one cell or battery, rechargeable or not, which is preferably housed inside the gripping member 2, by . example within said second 20A box. According to the invention, the electric toothbrush 1 comprises a drive shaft 7 extending longitudinally, preferably coaxially with the first axis of rotation YY' (which advantageously coincides with the central longitudinal axis XX"), between a first end 7A attached to said brush roller 4 and a second end 7B connected to said electric motor 6 for rotating, and preferably continuously as described above, said brush roller 4 via said drive shaft 7 along the first axis of rotation Y-Y'. To this end, the drive shaft 7 is preferably connected, at its second end 7B, to an output shaft 6A of the electric motor 6.The output shaft GA has, for example, a polygonal cross-section (for example, a square cross-section) and is inserted into a conjugate shape recess located at the second end 7B, thus enabling rotational drive along the first axis of rotation YY' of the drive shaft 7 by the motor 6. The brush roller 4 extends longitudinally (i.e., in the direction materialized by the central longitudinal axis XX") between a proximal end 40 attached to said drive shaft 7, for example at the first end 7A of the latter, and a distal end 41. Said distal end 41 is free, i.e., it is not extended or held, in particular by a mechanical guide.The use of a free distal end 41 allows the toothbrush roller 4 to have a degree of mobility, in particular by facilitating the flexural deformation of the central core 4A, which allows the toothbrush roller 4 to deflect, thus promoting brushing that is not only effective and precise, but also particularly gentle and atraumatic. Preferably, the drive shaft 7 advantageously comprises a central well opening at the first end 7A and within which is inserted a terminal portion 40A of the central core 4A, which projects axially from the brush roller 4. Preferably, the terminal portion 40A is press-fitted into the well at the first end 7A of the drive shaft 7, so as to allow rotational drive, about the first axis Y-Y', of the central core 4A by the drive shaft 7. Optionally, this frictional fastening can be supplemented by additional fastening means (e.g., bonding). Thus, the central core 4A extends advantageously in continuity with the drive shaft 7, the latter being advantageously coaxial with the first axis of rotation Y-Y', which itself is advantageously coincident with the central longitudinal axis X-X', as illustrated in the figures. As illustrated in the figures, the toothbrush 1 further comprises a first housing 30 within which the drive shaft 7 extends, at least in part. In the In the embodiment illustrated in the figures, a first part of the drive shaft 7 extends within the first housing 30 while a second part of said drive shaft 7 extends within the second housing 20A, said first and second parts of the drive shaft 7 being able to be removably connected to each other, in order to allow the separation of the brush head 3 and the main body 20. It is, however, perfectly conceivable, without departing from the scope of the invention, that the brush head 3 and the main body 20 are not detachable, so that the toothbrush 1 in this case has a monobloc character, with a single housing within which the drive shaft 7 extends entirely. The first housing 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 from the polyester family such as poly(butylene terephthalate) (PBT), or even a composite material formed, for example, of a thermoplastic polymer matrix loaded with glass fibers. As illustrated in the figures, the toothbrush | also includes a cover 8 which extends longitudinally from the first housing 30 and along the brushing roller 4 between a rear end 8A fixed to the first housing 30 and a free front end 8B. In other words, the cover 8 extends longitudinally substantially parallel to the central longitudinal axis XX", from an extremity of the first housing 30, so as to cover part of the fictitious cylindrical surface within which the brushing roller 4 is inscribed. The cover 8 thus helps to form a screen that leaves only a portion of the lateral surface of the brushing roller 4 exposed. Preferably, the cover 8 is formed by a tab, which is advantageously slightly curved to follow the profile of the brushing surface defined by the roller 4.The hood 8 thus has a leg-like shape that extends preferentially along substantially the entire length of the roller 4. More precisely, the hood 8 has an inner face 80 located opposite the brushing roller 4, and an opposing outer face 81. The hood 8 is advantageously made of a first material, which is, for example, a relatively rigid plastic, such as a thermoplastic polymer. The thermoplastic polymer forming said first material may, for example, be a styrenic polymer such as acrylonitrile butadiene styrene (ABS) or a polymer from the polyester family such as poly(butylene terephthalate) (PBT).The hood 8, however, has a significantly flexible character, so that it can deform in bending and possibly in torsion, to accompany, for example, a combined deformation of the roller 4, which again contributes to a particularly efficient, precise and atraumatic brushing. Advantageously, the hood 8 is formed from the same material as the first housing 30. This means that in this preferred relationship mode illustrated in the figures, the hood 8 and the first housing 30 are formed from a single piece, obtained for example by molding a plastic material (such as a thermoplastic polymer like ABS or PBT as mentioned above), the first housing 30 forming a hollow envelope delimiting an internal housing for the drive shaft 7, said hollow envelope being extended by a flat spatula-shaped piece corresponding to the hood 8. As illustrated in the figures, the drive shaft 7 includes an end section 70 emerging from the first housing 30 and including the first end 7A. In other words, the end section 70 extends partly outside the first housing 30 and partly inside it, protruding such that the first end 7A is located outside the first housing 30. To ensure the guidance of the drive shaft 7 and to maintain the toothbrush roller 4 in a suitable position, the toothbrush 1 includes a bearing that is integral with the first housing 30 and receives the end section 70 for guidance. The bearing thus allows the end section 70 to be held locally in position relative to the first housing 30, while permitting the rotation of the drive shaft 7 about the first axis of rotation YY*. According to the invention, the electric toothbrush includes a protective part 9 made of a second material that is more flexible than the first material. This second material preferably exhibits elastic, deformable, and soft properties. 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, and even more preferably between 50 and 70, and particularly preferably is approximately 60. The second material is, for example, an elastomer, or a thermoplastic elastomer (TPE), such as polystyrene-β-poly(ethylene-butylene)-β-polystyrene (SEBS) or polystyrene-β-polybutadiene-β-polystyrene (SBS). It is also possible to use, for example, a silicone-type second material. The protective piece 9 is therefore advantageously less hard and more flexible than the hood 8. As illustrated in the figures, the protective piece 9 covers the inner face 80 of the hood 8 and extends beyond it to form a peripheral lip 90 surrounding said hood 8. In other words, the peripheral lip 90 covers the inner face 80 and extends laterally beyond the hood 8, thus forming with the latter an atraumatic protective guard. This protective guard aims to prevent tissues in the oral cavity that are not affected by the brushing action of roller 4 from coming into unintentional contact of the brushing roller 4, which could cause discomfort, or even trauma. In other words, the sub-assembly formed by the cover 8 and the protective piece 9 acts as a spreader covering part of the lateral surface of the brushing roller 4, so as to protect from the action of said roller 4 the mucous membranes near the teeth, and more particularly the cheek, the lips or even the tongue. Thus, the cover 8 and the protective piece 9 help to form a kind of shield which masks a non-functional area of ​​the brushing roller 4, in order to protect the labial, cheek and lingual mucous membranes from the abrasive action of the roller 4. The shield in question thus makes it possible to separate the mucous membranes of the teeth to be brushed and thus provide sufficient space to place the roller 4 in the right position and allow the rotational movement of the latter along the vestibular, palatal and lingual faces of the teeth, both upper and lower.In other words, this technical measure makes it possible to obtain, by combining the cap 8 and the protective piece 9, a retractor that effectively protects the mucous membranes while being extremely flexible, deformable and atraumatic. In addition, the protective part 9 includes a ring 91 locally surrounding said extreme section 70 to form said bearing. The highly specific design described above offers significant advantages. This design allows for a dual-material protective guard that provides both high user comfort, minimizing the risk of injury, and controlled flexibility thanks to the presence of the cover 8, which is more rigid than the protective piece 9. Furthermore, the use of a ring 91 made of the second material to form the guide bearing for the drive shaft 7 at the output of the first housing 30 allows for variation in the angular orientation of said drive shaft 7. The inclination of the tooth-brushing roller 4 relative to the central longitudinal axis XX" is thus facilitated, resulting in greater comfort, precision, and brushing efficiency.The tooth-brushing roller 4 and the protective guard formed by the combination of the protective piece 9 and the cover 8 are thus advantageously capable of deflecting in a substantially simultaneous manner, possibly according to different deformation profiles, allowing the end of the brush head 3 to have an evolving shape capable of dynamically adapting to the mechanical stresses affecting the brush head 3 during use. This deformability is optimized by the implementation, in combination with the characteristics mentioned above, of a brushing roller 4 whose distal end 41 is free, i.e., unguided. In particular, the combined flexibilities of the hood 8 and the protective piece 9 allow significant flexibility of the head 3 relative to the handle 2 and the central longitudinal axis XX° associated with the latter, according, for example, to a deflection angle (measured between the first axis YY” and the central longitudinal axis XX”) which can reach approximately 7°. The specific design described above thus allows for respecting the proprioception of the dental organs and the heightened sensitivity of the gingival tissue to cuts. Furthermore, the combined presence of the peripheral lip 90 and a ventral zone 92, formed by the protective piece 9 and preferably covering substantially the inner face 80, helps to protect the tissues during the deflection of the brushing roller 4. Thanks to the preferably complete covering of the inner face 80 by a layer of the second material forming said ventral zone 92 of the protective piece 9, the brushing protrusions 5 that might come into contact with the inner face 80 during use rub against the ventral zone 92, which, due to its flexible and preferably smooth consistency, preserves the integrity of the protrusions 5 and limits their deterioration by abrasion. The specific design chosen thus avoids any contact of the teeth with a hard point area or hard surface, which again contributes to the atraumatic and comfortable nature of the brush 1. Advantageously, the protective piece 9 includes a front wall 9A extending in front of the distal end 41 of the toothbrush roller 4, so as to mask the latter to prevent potentially traumatic contact of the front face of the toothbrush roller 4, corresponding to the distal end 41, with the mucous membranes. The brush roller 4 is thus interposed between the ring 91 on the one hand and the front wall 9A on the other. For example, said front wall 9A includes a plurality of bristles extending parallel to a plane substantially perpendicular to said first axis of rotation Y-Y', and therefore also, in this case, perpendicular to said central longitudinal axis XX. Said plurality of bristles of the front wall 9A thus forms a flexible lining arranged opposite the distal end 41 of the brush roller 4, in the axial extension thereof and substantially transverse to the first axis of rotation YY.The soft padding formed by the bristles in question covers the brushing roller 4 in an area that is not normally used, preventing any interference between this non-functional area and the mucous membranes. This padding is also soft, gentle on the tissues, and provides a comfortable brushing experience. Advantageously, the bristles forming this soft padding can also be used for brushing. These bristles extend, for example, in two rows arranged one behind the other as illustrated in the figures, forming a tuft of bristles that not only protects the mucous membranes on the free front surface of the roller 4 but also provides a brushing function in addition to that provided by the brush itself. 4-roll toothbrush. Advantageously, the protective part 9 is formed by a single, one-piece component that includes a central body with a recess 93 for a tight fit of the cover 8, said central body being provided with the ring 91 at one end and with the plurality of studs forming the front wall 9A at the other end. The one-piece component that forms the protective part 9 can thus be obtained by molding plastic material, for example by molding 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 overmolded onto the cover 8 and the top of the first housing 30, as illustrated in the figures. This embodiment is preferred because it allows for simple, rapid, and economical industrial manufacturing. The implementation of a bearing formed at least in part by the ring 91, which fits over the top of the first housing 30 at an opening through it and from which the extremal section 70 emerges, also facilitates manufacturing, by allowing, thanks to its deformability, the insertion of the web 4A into the well opening at the first end 7A of the drive shaft 7. Advantageously, and as illustrated in the figures, the brush head 3 incorporates said brush roller 4, first housing 30, cover 8, and protective piece 9. In the preferred embodiment illustrated in the figures, the drive shaft 7 advantageously comprises: - a receiving section 700 carried by the brush head 3 and including said first end 7A - and a motor section 701 which is carried by the main body 20 and includes said second end 7B. The receiver section 700 is thus advantageously housed within the first box 30, while the motor section 701 is advantageously housed within the second box 20A. Advantageously, the receiving section 700 is provided with a first mechanical coupling means 700A, while the driving section 701 is provided with a second mechanical coupling means 700B, intended to cooperate with the first mechanical coupling means 700A when the brush head 3 is attached to the main body 20, to establish a mechanical drive connection between the receiving section 700 and the driving section 701. More specifically, said first and second mechanical coupling means 700A, 700B are complementary for removably connecting said driving section 701 and receiving section 700 in rotation. Preferably, at least one of said first and second means The first and second mechanical coupling means 700A and 700B form a female coupling element, while the other of said first and second mechanical coupling means 700A and 700B form a conjugate male coupling element. For example, the first mechanical coupling means 700A is formed by a polygonal coupling recess located at a free end of the receiving section 700 opposite the first end 7A, while the second mechanical coupling means 700B comprises a conjugate polygonal coupling tip located at a free end of the driving section 701 opposite the second end 7B. This coupling tip thus forms a multi-faceted tip designed to fit into the aforementioned coupling recess to transmit to the receiving section 700 the rotary motion of the driving section 701 imparted by the motor 6. Preferably, in accordance with the embodiment illustrated in the figures, the drive shaft 7 includes a first shoulder 10, which is, for example, positioned such that the end section 70 extends between the first end 7A and the first shoulder 10. Advantageously, the drive shaft 7 also includes a second shoulder 11, which is preferably located between the first shoulder 10 and the first mechanical coupling means 701. Advantageously, the receiving section 700 thus includes the first and second shoulders 10, 11, the latter being able, in particular, to hold the receiving section 700 in position within the first housing 30 of the head 3, as will be seen from the following description. Advantageously, the first and second shoulders 10, 11 are arranged opposite each other, that is to say, they define respective bearing surfaces facing each other, as illustrated in the figures.The said first and second shoulders 10, 11 are further arranged at a distance from each other, so that the drive shaft 7 includes an intermediate section 71 which extends between the said first and second shoulders 10, 11. Advantageously, the first housing 30, within which extends the receiving section 700 which advantageously carries the first and second shoulders 10, 11, includes within it an elongated cavity 30A delimited by a cavity wall 30B. The latter preferably has a substantially revolution-shaped form about the central longitudinal axis XX", and its cross-section varies longitudinally (i.e., along the central longitudinal axis XX") so as to form first and second axial stops 300, 301 for the first and second shoulders 10, 11 respectively. The cavity wall 30B therefore has different portions with different cross-sections, the first and second axial stops 300, 301 being formed by notches at the interface between two adjacent portions of different cross-sections. Thus, the first shoulder 10 is intended to bear against the first stop. axial 300, while the second shoulder 11 is intended to bear against and against the second axial stop 301, which makes it possible to lock the axial position of the drive shaft within the first housing 30. Preferably, each of said first and second shoulders 10, 11 forms a respective stopping surface extending in a respective plane which is substantially perpendicular to the central longitudinal axis XX".Similarly, the first and second axial stops 300, 301 are advantageously formed by flat annular surfaces which each also extend in a respective plane substantially perpendicular to the central longitudinal axis X-X'. This design, which implements two plane / plane stops facing each other, makes it possible to lock the shaft 7, and more precisely the receiving section 700, in a predetermined axial position within the first housing 30, with precise control of the play related to the positioning of the drive shaft 7 in said first housing 30. In order not only to facilitate manufacturing but also to obtain a precise and robust mechanical assembly, the drive shaft 7 preferably includes separate first and second elements 72, 73 assembled together and forming respectively said first and second shoulders 10, 11. Preferably, said first and second elements 72, 73 are part of the receiving section 700 and form the latter when assembled together. The first element 72, for example, forms the end section 70 and the intermediate section 71. Preferably, the first and second elements 72, 73 are assembled together by press-fitting, that is, by forcing a female element into a male element. The second element 73 extends for example longitudinally between a primary end and a secondary end and includes an assembly sleeve 730 which opens at the level of said primary end.The said assembly sleeve 730 receives an assembly end piece 720 which is part of the said first element 72 and extends, for example, the said intermediate section 71. The said assembly end piece 720 is thus forcibly inserted into the aforementioned sleeve 730 of the second element 73 to ensure a mutual fastening of the said first and second elements 72, 73. Advantageously, the second element 73 forms, at its aforementioned secondary end, the said first mechanical coupling means 700A, which is, for example, in the form of a hexagonal recess opening at the said secondary end.Preferably, said fitting is based on the principle of the Morse taper, that is to say that the assembly end piece 720 located in the axial extension of the intermediate section 71 has substantially a low-slope conical shape, while the wall of the assembly sleeve 730 located at the primary end of the second element 73 also has a low-slope conical shape, said conical end piece 720 being fitted into the conical cavity of the sleeve 730, which not only allows the first and . second elements 72, 73 to each other, but also to ensure excellent relative centering of the latter. Advantageously, the intermediate section 71 extends at a distance from the cavity wall 30B, i.e., there is a clearance JO between the cavity wall 30B and the drive shaft 7, over at least part of the latter's length. Thanks to the presence of this gap between the intermediate section 71 and the cavity wall 30B, the drive shaft 7 is allowed, during operation, to flex and / or tilt relative to the central longitudinal axis XX", which, in combination with the flexible nature of the bearing ring 91, gives the tooth-brushing roller 4 a particularly atraumatic character and an ability to conform geometrically to the anatomical shapes with which it interacts during brushing. The design described above thus 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 provides said shaft 7 with a local mobility capability, laterally relative to the central longitudinal axis XX", which confers great ease of use and remarkable brushing efficiency. Advantageously, the first axial thrust bearing 300 is positioned substantially adjacent to the bearing, and therefore to the ring 91. The aforementioned intermediate section 71 includes a first portion 710 which is advantageously adjacent to the first shoulder 10 and has a conical shape with a cross-section decreasing from the first shoulder 10 to the second shoulder 11 between a maximum and a minimum cross-section. The presence of the first conical portion 710 in the vicinity of the bearing allows the drive shaft 7 to self-center, while permitting its temporary deformation and inclination thanks to the clearance JO which increases along the first portion 710 towards the second shoulder 11. Advantageously, the intermediate section 71 includes a second portion 711 which is substantially adjacent to the first portion 710 and has, for example, a substantially cylindrical shape whose cross-section is less than or equal to the aforementioned minimum cross-section. Preferably, the cross-section of the second portion 711 is less than the aforementioned minimum cross-section, the second portion 711 being separated from the first portion 710 by a chamfer 712. Thanks to these geometric characteristics, the first element 72 is easy and quick to mount and assemble with the second element 73. The second element 73, for its part, has a substantially revolutionized shape with two different sections. Thus, the part of the second element 73 that forms the aforementioned assembly sleeve 730 has a first transverse section di- dimensioned to leave a clearance J1 between the cavity wall 30B and the relevant part of the second element 73, which limits friction, facilitates assembly, and promotes the bending and / or tilting of the drive shaft 7. The second element 73 also includes a second part 731 which has a larger cross-section than the first part mentioned above. This second part 731 incorporates, as previously mentioned, the first mechanical coupling means 700A. The cross-section of the cylindrical second part 731 is adjusted to that of the cavity 30A so as to locally maintain the drive shaft 7 coaxial with the central longitudinal axis XX. Thus, in the specific design illustrated in the figures and described above, the drive shaft 7 is kept centered on the central longitudinal axis XX" only in two spaced areas, corresponding respectively to the extremity section 70 and to the second part 731 of the second element 73, said drive shaft 7 being everywhere else disposed at a distance from the cavity wall 30B of the first housing 30. This particular design not only allows precise control of the play related to the positioning of the shaft 7 in the first housing 30, as mentioned previously, but also allows for deformation of the drive shaft 7 during operation, which makes it possible to obtain a particularly efficient and atraumatic brushing. In order to reduce parasitic vibrations that may be induced by potential misalignments of mechanical components due to manufacturing tolerances, the drive shaft 7 comprises a first section 80 and a second section 81 and a cardan joint 12 to connect said first and second sections 80, 81. The first section 80 preferably includes said second end 7B and a mechanical coupling means to the output shaft 6A, formed for example by the imprint disposed at the level of the second end 7B mentioned previously. The first section 80 comprises a male part of said cardan joint 12, which itself includes a substantially spherical convex part 80A projecting outwards as well as lugs 80B, 80C which extend laterally, perpendicular to the central longitudinal axis XX". The second section 81 advantageously includes the motor section 701 mentioned previously.In this case, said motor section 701 is provided with a spherically curved concave portion 81A whose shape is conjugate to that of the spherically convex portion 80A of the first section 80. Said spherically convex portion 80A and spherically curved concave portion 81A are in sliding contact to form a ball joint. Advantageously, said spherically curved concave portion 81A extends into a cylindrical cap into which the apex of the first section 80 is inserted, which carries said spherically convex portion 80A and said lugs 80B, 80C. Said cylindrical cap advantageously comprises two openings of . Guides that accommodate the lugs 8S0B, 80C, to allow relative axial sliding of the first and second sections 80, 81, but with rotational locking around the first axis of rotation YY. The universal joint 12 thus forms a spherical finger joint, compensating for potential misalignment of the driving section 701 and the driven section 700. Preferably, the guide lugs 80B, 80C, which transmit the rotary motion imparted by the motor 6, extend along a transverse axis passing through the center of the sphere in which the surface of the convex spherical portion 80A is inscribed. The universal joint 12, conforming to the preceding description, thus provides a rigid stop ensuring the positioning of the assembly while retaining the possibility of pivoting around the first axis of rotation YY' within a cone whose apex half-angle is advantageously greater than or equal to 5°.The implementation of the universal joint 12 makes it possible in particular to avoid operating under stress and therefore improves the lifespan of the mechanical components concerned, while providing increased user comfort by reducing any parasitic vibrations induced by potential misalignment, as mentioned previously. Furthermore, the second section 81 advantageously includes, at its end opposite the universal joint 12, the second mechanical coupling means 700B. As mentioned previously, the second mechanical coupling means 700B advantageously includes a multi-sided end piece, which advantageously extends into a cylindrical guide head 700C that facilitates the centering and insertion of the end part of the driving section 701 into the end part of the driven section 700. Advantageously, the toothbrush 1] includes a lip seal 13 which preferably has a shape of revolution and locally surrounds the motor section 701, and in this case the second section 81, on a portion of the latter which is adjacent to an opening provided in the second housing 20A and from which the second mechanical coupling means 700B emerges. Said seal 13 advantageously has facing shoulders to axially maintain the seal 13 in position within the second housing 20A, while ensuring the liquid-tightness of the latter, including during rotation of the drive shaft 7, and regardless of the rotational speed applied. The rotational speed of the brush roller 4 can advantageously be controlled by means of a suitable control interface located, for example, on the second housing 20A. This control interface includes, for example, a button 200 for increasing the rotational speed and a button 201 for decreasing it. The control interface is, of course, advantageously connected to the motor 6 via a control device, which includes, for example, an electronic board, which is preferably embedded within the second housing 20A. Advantageously, the brush 1 can include a screen 203 displaying, for example, the brushing time and / or the level of the rotation speed of the roller 4. Advantageously, the control interface also includes an on / off button 202 which is associated with the electrical switch allowing the brush 1 to be switched on or off. Preferably, said cover 8 and protective piece 9 form a unit subassembly which, in the absence of mechanical stress exerted upon it, occupies a rest position (illustrated in the figures), in which said unit subassembly 8, 9 extends longitudinally along a direction of extension substantially parallel to said first axis of rotation Y-Y'. Thanks to the combination of materials from which it is formed, said unit subassembly exhibits significant flexibility, which thus makes it possible to limit, or even completely avoid, traumatic contact with tissues (teeth and gums). Preferably, said unit subassembly thus designed: - to flex elastically relative to said first housing 30, in response to a first bending stress exerted on it, to reach a first position of maximum elastic bending in which said free front end 8B moves away from said first axis of rotation YY” such that said direction of extension forms with said first axis of rotation YY” a first angle between 3 and 10°, preferably substantially equal to 5°, and / or - to bend elastically relative to said first housing 30, in response to a second bending stress exerted on it, which is in the opposite direction to said first bending stress, to reach a second position of maximum elastic bending in which said free front end 8B approaches said first axis of rotation YY” so that said direction of extension forms with said first axis of rotation YY” a second angle between 1 and 4°, preferably substantially equal to 2°. Ultimately, the invention presents a design that facilitates the geometric variability of the brush head 3 according to the mechanical stresses to which it is subjected during use, while maintaining extremely reliable operation and preserving the service life of the mechanical components involved. The brush 1 according to the invention thus provides particularly effective and atraumatic brushing, while being robust, lightweight, and durable.

Claims

Demands

1. Electric toothbrush (1) comprising an electric motor (6), a toothbrush roller (4), drive shaft (7) extending longitudinally between a first end (7A) attached to said brush roller (4) and a second end (7B) connected to said electric motor (6) to rotate said roller (4) brushing via said drive shaft (7) according to a first axis of rotation (YY”), said brush roller (4) extending longitudinally between a proximal end (40) attached to said drive shaft (7) and a distal end (41) free, the said toothbrush (1) further comprising a first case (30) within which extends said drive shaft (7), as well as a hood (8), made of a first material, which extends longitudinally- finally said first casing (30) and extends along said roller (4) of brushing between a rear end (8A) fixed to the first housing (30) and a free front end (8B), said hood (8) having a face internal (80) located opposite said brush roller (4) and a face external (81) opposite, said drive shaft (7) comprising a extreme section (70) emerging from said first casing (30) and which includes said first end (7A), said toothbrush (1) including a bearing which is integral with said first housing (30) and receives said extremity section (70) to guide it, said toothbrush electrical (1) being characterized in that it comprises a pro- part tectrice (9) made of a second material more flexible than said first material, said protective piece (9) covering said inner face (80) and extending beyond the latter to form a peripheral lip (90) surrounding said hood (8), said protective piece (9) including a ring (91) locally surrounding said extremal section (70) to form said level.

2. Electric toothbrush (1) according to the preceding claim ca- characterized in that said protective part (9) includes a front wall (9A) which extends in front of said distal end (41), so that said brush roller (4) is interposed between said ring (91) on the one hand and said front wall (9A) on the other hand.

3. Electric toothbrush (1) according to the preceding claim ca- characterized in that said front wall (9A) includes a plurality of studs which extend parallel to a plane that is substantially perpendicular audit first axis of rotation (YY”).

4. Electric toothbrush (1) according to any one of the claims previous ones characterized in that said hood (8) comes from material with said first case (30).

5. Electric toothbrush (1) according to any one of the claims previous ones characterized in that said drive tree (7) includes the first and second shoulders (10, 11) arranged opposite and at distance from each other, said first housing (30) including within it an elongated cavity (30A) delimited by a cavity wall (30B) of which the cross-section varies longitudinally so as to form first and second axial stops (300, 301) for respectively the said first and second shoulders (10, 11).

6. Electric toothbrush (1) according to the preceding claim ca- characterized in that said drive shaft (7) comprises a section intermediate (71) which extends between the said first and second shoulders (10, 11), at a distance from said cavity wall (30B).

7. Electric toothbrush (1) according to the preceding claim ca- characterized in that said first axial stop (300) is arranged in in a substantially adjacent manner to said landing, said intermediate section (71) including a first portion (710) which is adjacent to said first shoulder (10) and has a conical shape with a section transverse decreasing from the first shoulder (10) towards the second shoulder (11) between a maximum cross-section and a section minimum transverse width.

8. Electric toothbrush (1) according to the preceding claim ca- characterized in that said intermediate section (71) includes a second portion (711) which is substantially adjacent to said first portion (710) and has a substantially cylindrical shape whose cross-section cross-section is less than or equal to said cross-section minimal.

9. Electric toothbrush (1) according to any one of the claims 5 to 8 characterized in that said drive shaft (7) includes first and second distinct elements (72, 73) assembled one to the other, for example by fitting, and forming respectively the said first and second shoulders (10, 11).

10. Electric toothbrush (1) according to any one of the claims previous ones characterized in that they comprise on the one hand a body main (20) and on the other hand a brush head (3) mounted in such a way removable on said main body (20), said main body comprising a second housing (20A) which forms a manual gripping device (2) and within which is housed said electric motor (6) while said The brush head (3) carries said brush roller (4), first housing (30), cover (8) and protective piece (9), said drive shaft (7) comprising: - a receiving section (700) carried by said brush head (3) and including said first end (7 A), said receiving section (700) being equipped with a first mechanical coupling means (700A), - a motor section (701) carried by said main body (20) and including said second end (7B), said motor section (701) being equipped with a second mechanical coupling means (700B), the said first and second mechanical coupling means (700A, '700B) being complementary for linking in rotation in a removable manner said motor section (701) and receiver section (700).

11. Electric toothbrush (1) according to claims 5 and 10 characterized in that said receiving section (700) includes said first and second shoulders (10, 11).

12. Electric toothbrush (1) according to any one of the claims previous characterized in that said drive shaft (7) includes a first section (80) and a second section (81) as well that a universal joint (12) to connect the said first and second sections (80, 81).

13. Electric toothbrush (1) according to any one of the claims previous, characterized in that the said hood (8) and protective piece (9) form a unitary subset which occupies, in the absence of soll- mechanical citation exerted on him, a resting position in which said unit subset extends longitudinally along a direction of extension substantially parallel to said first axis of rotation (YY”), said unit subset being designed: - to flex elastically relative to said first housing (30), in in response to an initial bending stress exerted on it, for to reach a first position of [maximum elastic tension in which said free front end (8B) deviates from said first axis of rotation (Y-Y') such that said extension direction forms with said first axis of rotation (YY”) a first angle between 3 and 10°, preferably approximately equal to 5°, and / or - to flex elastically relative to said first housing (30), in in response to a second bending stress exerted on it, which is in the opposite direction to said first bending stress, to reach a second maximum elastic bending position in which said free front end (8B) approaches said first axis of rotation (YY”) so that said extension direction forms with said first axis of rotation (YY”) a second angle between 1 and 4°, preferably substantially equal to 2°.