BRUSH HEAD, IN PARTICULAR FOR AN ELECTRICALLY DRIVEN TOOTHBRUSH, AND METHOD FOR THE PRODUCTION THEREOF

Description

[0001] The present invention relates to a brush head for an electrically powered toothbrush. Such a brush head is typically sold as a component of an attachment that can be connected to a handle of the electrically powered toothbrush, which typically houses the drive. The attachment is a consumable part and is made of plastic. The attachment typically comprises a sleeve through which a drive shaft extends, which can be connected to a drive shaft of the handle. The brush head according to the present invention is usually located at the free end of the sleeve.

[0002] In principle, cleaning elements for the oral cavity need to be very compact and space-saving, as the space in the oral cavity is limited, and cleaning buccal tooth surfaces is already difficult due to the immediately adjacent cheek.

[0003] There are various ways to attach bristle bundles, which are typically used for tooth cleaning, to a bristle carrier. The in-mold process, in which a thickened portion is formed on the bristle bundle and sealed with liquid plastic, which forms the bristle carrier or at least part of it, allows the production of brushes with a relatively low height. For the purposes of the present invention, height is defined as the extension essentially parallel to the filaments of the bristle bundles.

[0004] A brush head with the preamble features of claim 1 is known from EP 2 599 403. In this brush head, the holding part acts as a pin for connecting the brush head to a drive element of the attachment part. Accordingly, the holding part primarily serves to impart a typically reversibly applied drive torque, by which the brush head is pivoted about its pivot axis. This holding part is connected to a plate-shaped carrier part, which supports bristle bundles formed by bristle filaments, attached thereto using in-mold technology. During the in-mold process, the bristle bundles are melted at the ends to form a thickened portion. Prepared in this way, they protrude through a mold cavity into which a plastic component forming the carrier part is injected. The previously known brush head furthermore carries flexible cleaning elements.These are connected on the fastening side to a plastic mounting base, which forms a widened anchoring head that extends through a through-hole and locks behind it like a snap lock. The anchoring head is accommodated in a widened snap-in receptacle that is open at the rear of the support part. This attachment of the flexible cleaning element to the brush head allows a certain degree of pivoting of the flexible cleaning element relative to the support part.

[0005] This design is disadvantageous, however, because the anchoring head requires the support part to be a certain height, which contradicts the need for a brush that is as low as possible. Furthermore, bacteria or dirt can nestle in the locking receptacle, which is open at the rear. Passing the anchoring head through the through-hole formed in the support part also requires a certain tolerance, so that germs or dirt can nestle within the through-hole and between the support part and the fastening base, which contradicts the hygienic requirements that must be met by a brush head of a toothbrush. Further examples of brush heads for electrically powered toothbrushes are disclosed in EP 2 599 403 A1 and EP 3 165 126 A1 (this document falls under Art. 54(3) EPC).

[0006] The present invention is based on the problem of providing an improved brush head for an electrically driven toothbrush and a method suitable for producing such a brush head.

[0007] To solve the device-related problem, the present invention provides a brush head with the features of claim 1. In this brush head, the carrier part has through-bores, each of which is penetrated by the bristle bundle and the flexible cleaning element. The brush head according to the invention has at least one bristle bundle and at least one flexible cleaning element. Typically, through-bores are provided for each of these cleaning elements. One of the bristle bundles is accordingly received in a through-bore associated with this bundle. One of the flexible cleaning elements is provided in another through-bore associated with the respective cleaning element. However, it is also possible to provide a bristle bundle together with a flexible cleaning element in a single through-bore.In this case, the bristle bundle and the soft elastic cleaning element share a common through-hole.

[0008] According to the invention, the bristle bundle and the flexible cleaning element are positively secured to the carrier part. This securing is achieved by a thickened portion, which can be formed by the filament material, as is generally known from the in-mold process. However, contrary to the known in-mold process, the carrier part is usually first prepared with through-holes and only then provided with the bristle bundle or the flexible cleaning element. To positively secure the bristle bundle relative to the carrier part, the carrier part can first be stuffed with the bristle bundle and then the bristle bundle can be melted at its fastening-side end. This creates a thickened portion, through which the bristle bundle is positively secured relative to the carrier part and pressed against a rear side of the carrier part.Even more so, the filament material can be applied in molten form against an opening leading to the corresponding through-hole, and this opening can be sealed by moltenly bonding the filament material to the material of the carrier part. This process prevents molten plastic from entering the through-hole during the subsequent back-injection of the prepared carrier part.

[0009] In a similar manner, for example, a preform of a flexible cleaning element can be inserted into the through-hole and then heated at its fastening-side end to form the thickened portion. The preform can be configured, for example, as a cylindrical rod. This preform can, for example, simply be heat-stitched. In this process, the flexible material is simply softened and then plastically deformed to form the thickened portion.

[0010] Alternatively, the support part can be fitted with a prefabricated, flexible cleaning element. In this case, the prefabricated, flexible cleaning element already has a thickened portion provided on the fastening side. The prefabricated, flexible cleaning element is typically pushed from the rear of the support part through the through-hole until the thickened portion rests against the rear of the support part. The prefabricated, flexible cleaning element and the support part, usually manufactured by injection molding, can have sealing contours that engage with one another and, if necessary, lock together to seal the opening to the through-hole. In this way, a type of labyrinth seal can be formed between the support part and the flexible cleaning element in the area of ​​the through-hole to the corresponding cleaning element.Since the soft-elastic cleaning element has a high elasticity, the corresponding labyrinth seal can be effectively created by pressing the cleaning element against the carrier part and the soft-elastic cleaning element can be placed in a sealing manner against the carrier part so that the through-hole is sealed.

[0011] In an alternative process, the soft-elastic material used to form the soft-elastic cleaning element can be injected in molten form through the through-hole to create the soft-elastic cleaning element. This process step can take place either before or after the bristle bundle is plugged. For this purpose, a mold cavity is usually placed against the back of the carrier part, which forms a cavity suitable for forming the thickened portion. On the opposite side of the carrier part, which is usually prefabricated from plastic, a cavity is provided which serves to moltenly mold the cleaning-active area of ​​the soft-elastic cleaning element. This is usually rod-shaped, i.e. cylindrical, preferably with a circular cross-section. However, rectangular, polygonal, or oval cross-sections are also conceivable.After injection molding of the soft elastic material, the soft elastic cleaning element is provided with the thickening and thus connected to the carrier part at least in a form-fitting manner, preferably in a form-fitting and material-fitting manner.

[0012] Multiple flexible cleaning elements can have a uniform or common thickening, which can be manufactured by injection molding, forming, or hot-staking, or by prefabrication of multiple flexible cleaning elements with a common thickening. This thickening connects the cleaning elements to one another.

[0013] Sealing the through-bore with the filament material or the soft-elastic material is not a necessary feature of the present invention, but is nevertheless preferable. A carrier part provided with the soft-elastic cleaning element and the bristle bundle can, for example, be connected directly to the back of the holding part by injection molding in order to produce a brush head that is as compact as possible in terms of height. The holding part is usually made of an engineering plastic and has a high viscosity, which makes it necessary to inject the holding part into the injection mold at relatively high pressures. The holding part can form a plate molded in one piece on the holding part, the surface of which preferably extends essentially parallel to the surface of the carrier part. A plastic compound can be introduced between the holding part and the carrier part, which hardens to bond the carrier part and the holding part to one another.This plastic compound can be introduced, for example, by injection molding. Curing in this process preferably occurs when the plastic melt cools. The plastic compound can also be an adhesive that hardens or sets. If the holding part is provided with a plate, the surface of this plate, together with the rear surface of the carrier part, preferably forms a gap that is filled with the plastic compound to bond the carrier part to the holding part.

[0014] In the inventive design of the brush head as a brush head of an electrically powered toothbrush, a holding part has at least one connection element for the mechanical coupling of the brush head to the electric drive of the toothbrush. The holding part has a pin, preferably provided on one side thereof, which defines a rotation or pivot axis of the brush head. This holding part is usually located entirely or partially within the aforementioned sleeve element of the attachment part and is received therein in such a way that the brush head can perform a rotation or pivot movement relative to the sleeve element while being captively coupled to the sleeve element.In the simplest case, a connection element for the mechanical coupling of the brush head to the electric drive consists of a recess cut out on the pin, into which the drive shaft of the attachment engages, for example to impart a cyclical pivoting movement to the brush head relative to the sleeve element. In this case, the connection element is located on the outer circumferential surface of the holding part, i.e., it is cut out on the usually cylindrical pin with an extension perpendicular to the pivot axis defined by the holding part. At its free end, the pin typically has a centering bore that interacts with a centering pin of the sleeve element to define a bearing for the pivoting movement of the brush head.On the side usually opposite the connecting element, the pin usually has a locking recess into which a locking pin firmly connected to the sleeve element engages in order to fix the brush head within the sleeve element such that the brush head cannot be pulled along the pivot axis out of a receptacle for the pin formed on the sleeve element. The shaft provided in the sleeve element for coupling to the pin preferably has a substantially cylindrical locking head whose cylinder axis extends approximately parallel to the pivot axis of the locking pin. To accommodate this locking pin, the central pin usually has locking pin receptacles provided eccentrically to the pivot axis, but with a parallel extension thereto.

[0015] The previously discussed elements of the pin are usually located inside the sleeve element after it has been mounted on the sleeve element.

[0016] The central pin is preferably radially projected over by the plate, which is provided as a component of the holding part. The holding part is accordingly formed from the central pin and the plate. The plate typically has a base area that essentially corresponds to and / or runs parallel to the base area of ​​the brush head surface penetrated by the cleaning elements of the brush head. This surface can be circular or oval. In any case, the base area of ​​the surface, i.e., its contour, is selected with a convex peripheral edge to provide maximum protection against damage to the sensitive oral mucous membranes.

[0017] The carrier part preferably has a base area that corresponds to the surface traversed by the bristle bundle. The preferred disc-shaped carrier part usually forms this surface, i.e. forms the upper end of the brush head. The carrier part is preferably disc-shaped, i.e. has essentially coplanar main surfaces, one of which usually forms the surface of the brush head and the other is opposite the plate and usually extends parallel thereto and forms a contact surface for the thickened portions of the cleaning elements. The carrier part is preferably designed as a relatively thin plate with a thickness of between 0.5 and 3.0 mm. The plate can have a recess corresponding to the position of the respective thickened portion, which accommodates the corresponding thickened portion, thus promoting a compact design of the brush head.

[0018] The support part is usually connected to the retaining part in such a way that no vertical gap remains between the support part and the plate. The support part can be directly adjacent to the plate. The support part and the retaining part are usually formed as two separately manufactured components and subsequently joined. This connection can be achieved by welding, for example, ultrasonic or friction welding.

[0019] When joining by injection molding, the bristle carrier and the holding part are first placed in an injection mold to join the two initially separately manufactured components and held at a distance from one another so that the thickened portion of the bristle bundle and the soft elastic cleaning element are located between the upper side of the holding part, preferably the plate thereof, and the underside of the carrier part, preferably in sealing contact with the through-hole. A plastic compound is then injected into the gap remaining between the two parts, completely filling the gap and connecting the carrier part to the holding part. The intermediate layer formed in this way is preferably located as an overmolding not only between the carrier part and the holding part or plate. It can also completely or partially surround the plate and / or the carrier part.This makes it possible, for example, to produce an abutting edge made of a different material which surrounds the carrier part and the holding part on their circumference and defines the outer contour. The injected material is usually a thermoplastic. This plastic can be a soft, elastic material, for example TPE. Alternatively, the injected material can be formed from a hard component, for example PP, PE, PA, POM, PC or PBT. A free-flowing plastic is generally preferred, preferably a plastic with an MFI > 15 g / 10 min at 2.16 kg and a test temperature appropriate to the plastic. It is also possible to add an additive to the injected material which has a cleaning or polishing effect, so that the teeth or tissue areas within the oral cavity can be gently cleaned through the outer circumference of the brush head.

[0020] According to a further preferred embodiment of the present invention, the plastic introduced into the intermediate space engages over or under the carrier part or the plate of the holding part. In this case, care must usually be taken to ensure a design in which the plastic introduced into the intermediate space also transitions seamlessly and continuously into a surface of the carrier part or the holding part. For example, the carrier part can have a radial projection or radially circumferential edge that is provided at a distance from the surface of the carrier part and is overlapped by the plastic injected into the intermediate space in order to secure the carrier part in a form-fitting manner relative to the holding part. Similarly, the plastic injected into the intermediate space can also be provided on the underside of the plate.For this purpose, the plate can also form a radial projection which is gripped under by the solidified plastic introduced into the intermediate space in order to connect the plastic introduced into the intermediate space with the holding part in a form-fitting manner in the direction of the pivot axis.

[0021] In order to achieve the most solid connection possible, it is preferable to guide the plastic introduced into the gap radially up to the pin, so that the plastic introduced into the gap essentially covers the back of the plate and forms the underside of the widened part of the brush head, which projects radially beyond the usually cylindrical pin relative to the pivot axis. The plate and the support part can be designed with an identical base area, with the plastic introduced into the gap being limited to that gap. If the plastic introduced into the gap surrounds the support part or the plate all the way around, the outer contour of the widened part is defined, among other things, usually exclusively by the plastic introduced into the gap.However, the plastic introduced into the intermediate space can also be located only beneath the carrier part, so that this alone defines the surface penetrated by the bristle bundles and is backed on the back by the plate and the plastic injected into the intermediate space, which can also enclose the plate on the back in order to connect the carrier part to the holding part in a form-fitting manner, also in the direction of the pivot axis.

[0022] With a view to making the brush head according to the invention as simple as possible to manufacture, a preferred development of the present invention proposes that the carrier part or its plate and / or the holding part form a spacer that defines the intermediate space. The corresponding spacer is usually formed integrally on the carrier part or the plate. The spacer protrudes from the carrier part or the holding part in the direction of the pivot axis and rests with its free end on a counter surface formed by the carrier part or the plate. The spacer(s) can be provided on both the carrier part and the holding part to define the intermediate space.During the production of the brush head, the prefabricated parts (support part and holding part) are held at a distance in the injection mold by the spacers. They are already pressed against each other, which can lead to a certain deformation of the spacers. The remaining gap is filled during overmolding with the plastic injected into the gap, so that a brush head with predetermined dimensions can be produced, not least thanks to the spacers.

[0023] The height of the intermediate space preferably corresponds approximately to the size of the thickened portion in order to achieve the most compact brush head height possible. This criterion is already met if the height corresponds to 100 to 200% of the height of the thickened portion. The carrier part and / or the holding part are usually designed with a round or oval base. The opposing main side surfaces of the carrier part and holding part are usually essentially flat and generally parallel to one another. Only the previously mentioned spacers project beyond the opposing surfaces of the holding part or carrier part. The surface of the carrier part penetrated by the bristle bundles or soft-elastic cleaning elements usually forms between 90 and 100%, preferably 30 to 60%, of the brush head surface. Edge and intermediate spacings preferably take up between 40 and 70% of the brush head surface.This surface of the brush head is usually circular or oval.

[0024] The clearance of a brush head section that is wider than a pin is typically between 2.5 and 5.0 mm. The pin forms a pivot axis and, if installed in an electrically powered toothbrush, also drive surfaces for the brush head.

[0025] According to a further preferred embodiment of the present invention, knobs are provided on the rear side of the holding part or the plate, i.e. on the side facing away from the carrier part, which knobs are preferably formed integrally on the holding part. The free ends of these knobs are exposed on the underside of the brush body. The knobs usually extend parallel to the pivot axis. The aforementioned knobs also serve to position the holding part or the plate in an injection mold in such a way that the plastic introduced into the intermediate space can flow around the underside of the holding part and solidify there, so that this underside is essentially completely formed by the plastic introduced into the intermediate space and only the knobs with their free ends are exposed on this underside.This allows a predetermined layer thickness of the plastic introduced into the gap on the underside of the brush head to be easily specified. The nubs reliably and easily adjust the required spacing in the injection-molded material. The nubs are usually located radially inside an outer edge of the retaining part or plate, allowing the plate to be designed relatively thin at the edges and surrounded by the plastic introduced into the gap.

[0026] The previously mentioned spacers and / or knobs are usually provided distributed in the circumferential direction on the upper or lower surface of the bristle carrier and / or holding part or plate.

[0027] The present invention further relates to an attachment for an electric toothbrush, comprising a sleeve element, a drive shaft provided therein, which can be coupled to a drive of the electric toothbrush, and a brush head according to the present invention. The brush head is coupled to the drive shaft. The sleeve element has, at its end opposite the brush head, mechanical connection options for securing the attachment to the handle of the electric toothbrush. Furthermore, the drive shaft is designed at its end such that when the sleeve element is attached to the housing of the handle of the electric toothbrush, the drive shaft is coupled to the drive shaft of the handle in order to transmit the rotary movement of the drive shaft to the brush head. In this case, the brush head is usually pivoted, i.e.The drive shaft is not driven in a rotating manner, but is merely pivoted cyclically through a certain angular range.

[0028] Further details and advantages of the present invention will become apparent from the following description of exemplary embodiments in conjunction with the drawings, in which: Fig. 1 is a perspective, partially sectioned view of a first embodiment of the present invention; Fig. 2 is a cross-sectional view of a second embodiment; Fig. 3 is a cross-sectional view of a third embodiment; Fig. 4 is a cross-sectional view of a fourth embodiment; Fig. 5 is a cross-sectional view of a fifth embodiment; Fig. 6 is a cross-sectional view through an embodiment of a carrier part before connection to the holding part; Fig. 7 is a schematic representation of an electric toothbrush; Fig. 8 is a sectional view of the brush head of the electric toothbrush according to Fig. 7 ; Fig. 9 a perspective view of a drive pin of the electric toothbrush according to the Fig. 7 and 8 and Fig. 10 a cross-sectional view of the drive pin according to Fig. 9 with the hub in the joined state.

[0029] The figures each schematically depict the exemplary embodiments. Reference numeral 2 denotes a holding part which forms a pin 4 and a plate 6 projecting radially therefrom and provided as a single piece on the pin 4. A bristle bundle 8 extends through a through-bore 12 provided in a support part 10 and rests against the support part 10 with its thickened portion 14 on the rear side thereof. To simplify the illustration, Fig. 1Only one bristle bundle 8 is shown. It goes without saying that the entire surface 16 formed by the carrier part 10 is covered by bristle bundles 8 or other cleaning elements, but especially by soft-elastic cleaning elements, in order to achieve the most comprehensive cleaning effect possible. The bristle bundles and the cleaning elements can have different diameters, colors, material properties and contours, as well as different bristle filaments and different numbers of bristle filaments, as is common on the market. A cleaning element made of a thermoplastic elastomer is preferably considered as the soft-elastic cleaning element. The soft-elastic cleaning element preferably extends essentially parallel to the bristle bundle(s) 8.

[0030] The Fig. 1 to 5illustrate various examples of the arrangement of the carrier part 10 relative to the holding part 2. Details of the cleaning elements held in the through holes 12 of the carrier part 10 are shown in Fig. 6 and the corresponding description.

[0031] Fig. 6 and the corresponding description illustrate examples of bristle bundles or soft-elastic cleaning elements and their design.

[0032] Reference numeral 18 denotes a gap enclosed between the underside of the support part 10 and the top side of the plate 6. A spacer 20 protruding from the plate projects into this gap 18, resting against the underside of the support part 10 and holding it at a predetermined distance from the plate 6. Fig. 1only one such spacer 20 is shown, although several such spacers 20 protrude from the surface of the plate 6 in order to hold and support the carrier part 10 at specific points, but at different positions relative to the plate 6.

[0033] A stud 22 protrudes from the underside of the plate 6. Several of these studs 22 are also provided on the underside of the plate 6 and are integrally formed thereon.

[0034] Reference numeral 24 denotes a plastic material injected into the intermediate space 18. This plastic material completely fills the intermediate space 18. The plastic material 24 further surrounds the carrier part 10 circumferentially, but ends on the surface 16 flush with the carrier part 10. The plastic material 24 also surrounds the underside of the plate 6 and projects radially up to the pin 4. Due to this design, a widened part of the brush head, designated by reference numeral 26, is shaped in the manner of a disk, which is composed of the carrier part 10, the plate 6 and the plastic 24 injection-molded coating. The edges of the disk are each rounded. The plastic material 24 is in the present case a readily flowing thermoplastic elastomer, which not only surrounds the carrier part 10 and the Plate 6 togetherconnects, but also forms an outer border of the disc from a relatively soft material that is better for the sensitive oral mucous membranes than a harder plastic.

[0035] The holding part 2 is made of an engineering plastic. An engineering plastic has high wear resistance and a high modulus of elasticity of at least 1500 MPa. The viscosity of such an engineering plastic is relatively high. The MFI of an engineering plastic of the present invention is ≤ 20 g / 10 min at the test temperature corresponding to the plastic and a load of 2.16 kg. An engineering plastic is in particular POM, PA, PC or PBT. The holding part 2 is made of such a material. The pin 4 usually has the connections, holders and centering devices presented in the general description, with which the illustrated embodiment is held in a sleeve element (not shown) of an attachment for an electric toothbrush and can be mechanically coupled to the drive.

[0036] In the illustrated embodiment, the plastic 24 can provide adhesion between the carrier part 10 and the holding part 2 made of the engineering plastic. The bristle carrier can be formed from a hard component, for example, PA, PET, PP, PE, POM, PC, or PBT.

[0037] The Fig. 1 The embodiment shown assumes that a positive fit is necessary for the reliable attachment of the plastic 24 to the holding part 2. Thus, the plastic 24 also extends over the underside of the plate and accordingly forms the lower surface of the widened part 26, through which the pin 4 extends. The material properties of the support part 10, however, are such that the plastic 24 can be securely bonded to the support part 10 by a material fit alone. The plastic 24, however, surrounds the support part 10 circumferentially.

[0038] For the production of the Fig. 1In the embodiment shown, the carrier part 10 is first manufactured from plastic by injection molding, with the through-bore 12 or bores being formed during the injection molding process. The carrier part 10 is then filled with the bristle bundles 8, the fastening end of which is initially positioned at a distance from the carrier part 10 and melted. The bristle bundle 8 is then axially displaced to press the thickened portion 14 formed during the melting process against the underside of the carrier part.

[0039] The holding part 2 is prepared by injection molding from the engineering plastic to its final contour with all functional surfaces on the pins. The two prepared components 2 and 10 are placed into an injection mold. The holding part 2 is assigned to one mold half and the carrier part 10 to the other mold half. The carrier part 10 is usually held with a so-called perforated field plate, which is usually provided with the carrier part 10 outside the injection mold and then inserted into the injection mold to complete it. When the injection mold is closed, the spacers 20 are placed against the underside of the carrier part 10 and slightly compressed. The remaining space 18 is filled with the then injected plastic 24.The knobs 22 also keep the otherwise flat rear side of the plate 6 at a distance from the injection mold, so that a gap is left there, which is filled by the plastic 24 in order to form the rear overmolding of the plate with the plastic 24. After the plastic 24 has cooled sufficiently, the mold cavity is opened and the in . Fig. 1 schematically shown finished product.

[0040] The Fig. 2 shows a cross-section of a basic form of the present invention. Identical components are identified by the same reference numerals as in the previously described embodiment. This applies to all figures in the drawing.

[0041] In the basic form according to Fig. 2The intermediate space 18 is filled by the plastic 24. The plastic 24 ends flush with an outer peripheral surface of the widened part 26, which is formed at the top by the edge of the support part 10, at the bottom by the edge of the plate 6, and in between by the plastic 24.

[0042] In the embodiment according to Fig. 3 the plate has 6 opposite Fig. 2a smaller radial extent than the support part 10. The plastic 24 circumferentially surrounds both the support part 10 and the plate 6, but does not contribute to a greater thickness above the surface 16 or below the underside of the plate 6. The plastic 24 merely serves as impact protection, circumferentially surrounding the support part 10 and the plate 6. In such a configuration, the holding part 2 and the support part 10 are usually made of plastics that adhere to the plastic 24 injected into the intermediate space 18, resulting in a material-to-material connection in the direction of the pivot axis S.

[0043] The Fig. 4 The design shown essentially corresponds Fig. 2 , wherein spacers 20 formed integrally on the holding part 2 protrude from the plate 5 and bear against the underside of the carrier part 10 in order to define the intermediate space 18.

[0044] The Fig. 5The design shown essentially corresponds to the example according to Fig. 1 However, here the carrier part 10 has a locking edge 28 which is formed at a distance from the surface 16 and which projects radially beyond the surface 16 formed by the carrier part 10 and is engaged over by the plastic 24 in the direction of a pivot axis designated by the reference symbol S. As a result, the carrier part 10 is also positively secured against withdrawal in the direction of the pivot axis S. By engaging under the underside of the plate 6, a correspondingly effective positive connection is produced between the plastic 24 and the holding part 2. Furthermore, the plastic 24 surrounds both the carrier part 10 and the plate 6 on the outside circumference, so that a positive connection is also provided in a direction radial to the pivot axis S. The Fig. 5The embodiment shown is particularly suitable for connecting the different components when the material of the carrier part and the material of the holding part 2 are incompatible with the plastic 24.

[0045] The Fig. 6 illustrates a cross-sectional view through an embodiment of a carrier part 10, which is provided with a protruding collar 30 on the rear side in the region of a first through-bore 12.1 to the bristle bundle 8, against which the thickened portion 14 bears in a materially bonded manner. For this purpose, the filament material of the bristle bundle 8, i.e., the material forming the filaments of an individual bristle bundle 8, is melted at the fastening-side end of the bristle bundle 8 and applied in molten form against the collar 30, as described in WO 2016 / 097091 A1, which originates from the present applicant.

[0046] In addition to this bristle bundle 8, various embodiments of soft-elastic cleaning elements 32, 34, 36 are illustrated. The soft-elastic cleaning elements are preferably made of a thermoplastic elastomer, i.e., a material that can be processed by injection molding. The soft-elastic material preferably has a Shore A hardness of between 20 and 60. The soft-elastic cleaning element 32 projects beyond the surface 16 with a cylindrical configuration and is rounded at the front. At its opposite end, the soft-elastic cleaning element 32 has a thickened portion 38 that projects radially beyond the through-bore 12.2 and is sealingly applied against the rear side of the carrier part 10. The thickened portion 38 is formed from the material forming the soft-elastic cleaning element 32.The soft-elastic cleaning element 32 is an example of a prefabricated soft-elastic cleaning element, which is first prepared with the thickening 38, for example in an injection mold, and then pre-assembled and stuffed by insertion into the through-bore 12.2.

[0047] The soft-elastic cleaning elements 34, 36 are provided with different lengths relative to one another and have a common thickening 40 which connects the two rod-shaped areas of the cleaning elements 34, 36 to one another and thus positions the cleaning elements 34, 36 in a form-fitting manner on the rear side of the carrier part 10.

[0048] There are various ways to manufacture the illustrated brush head embodiments. Typically, the carrier part 10 is first manufactured as a plastic plate by injection molding. The carrier part 10 is then filled with bristle bundles 8, which are melted on the fastening side and sealed against the associated collar 30. Each bristle bundle 8 has a through-bore 12.1 associated with it. Prepared in this way, the carrier part 10 can be filled with the flexible cleaning elements, which are designed as prefabricated flexible cleaning elements 32 or 34, 36.

[0049] Alternatively, rod-shaped semi-finished products made of the soft-elastic material can be introduced into the respective through-holes 12.2 and heated or melted at their fastening-side ends to form a thickening 38 or 40.

[0050] Alternatively, the carrier part 10 can be inserted into an injection mold, which forms cavities for forming the flexible cleaning elements 32, 34, 36 with the associated thickenings 38, 40. These cavities can be connected to one another via common flow channels within the injection mold. Different cavities for flexible cleaning elements 32, 34, 36 can also be fluidically separated from one another in the injection mold in order to produce flexible cleaning elements of different material properties and / or colors. The flexible cleaning elements 32, 34, 36 are formed by injecting flexible plastic material, in particular TPE, into the cavities. These are positively secured to the carrier part 10 due to the thickening 38, 40. The molten application of the flexible material also results in a materially bonded connection. Thus, each channel is 12.1, 12.2 sealed on the back.

[0051] Plastic material can be injected against the carrier part 10 in another injection mold, forming the holding part 2. Alternatively, the holding part 2 can also be prepared as a separate component, and a plastic connecting the holding part 2 and the carrier part 10 can be introduced into the gap 18 formed as a gap in order to join the two parts 2, 10 together.

[0052] An electrically operated toothbrush 50 consists of a handle part 52 and an attachment part 54 which can be plugged onto the handle part 52. The handle part 52 accommodates an accumulator 56 or a battery, an electric motor 58 and a reversing device 60 which converts the continuous rotational movement of the drive shaft of the electric motor 58 into an alternating rotational movement of the brush head designated by reference numeral 61.

[0053] A switch 62 for activating the toothbrush 50 is arranged on the outside of the handle part 52. The attachment part 54 consists of a hollow support tube 66 accommodating a shaft 64. The support tube 66 and the shaft 64 can be connected to the handle part 52 via coupling means 70 (not shown in detail). The brush head 61 is arranged at the end of the attachment part 54 facing away from the handle part 52, and its pin 4 projects into the hollow support tube 66.

[0054] This pin 4 forms a drive pin 74 in the manner described in more detail below and can be slipped onto a hub 82 of a bevel gear segment 76. The bevel gear segment 76 meshes with another bevel gear segment 78 arranged at the head end of the shaft 64. The axis of rotation or axis of symmetry 92 of the brush head 61 forms an angle of approximately 90° with the axis of rotation of the shaft 64.

[0055] The torque of the alternately driven shaft 64 is transmitted to the brush head 61 via the bevel gear 72, consisting of the bevel gear segments 76 and 78. The rotation angle range covered by the brush head 61 can assume values ​​between + / - 20° and + / - 100°, but is preferably + / - 35°.

[0056] The representations of the Fig. 9 to 10show the drive pin 74 and the hub 82 and their adaptation to one another in detail. The hub 82 is arranged on the underside 86 of the drive pin 74. The drive pin 74 is arranged and held in the hub 82 in a rotationally fixed manner. The hub 82 is equipped with a sleeve-shaped recess 90 which is arranged eccentrically to the axis of rotation or axis of symmetry 92 of the brush head 61. The recess 90 is formed by two parallel side walls 94, to which cylindrical side wall sections 96, 98 adjoin. A base 100 delimits the recess 90 in the direction of an upper side 102 of the brush head 61. The center point 104 of the side wall section 98 coincides with the axis of symmetry 106 of the brush head 61. The side walls 94 each have a groove 108 running parallel to the axis of symmetry 106 and an adjacently arranged spring 110. The spring 110 orGrooves 108 of each side wall 94 are arranged opposite each other.

[0057] The drive pin 74 is designed according to the negative image of the hub 82 and has parallel side walls 112, to which cylindrical side wall sections 114, 116 adjoin. The side walls 112 have corresponding tongues 118 and grooves 120 running parallel to the axis of symmetry 92. The grooves 108, 120 or the tongues 110, 118 of the recess 90 or the drive pin 74 can also be arranged in an edge region 122, in which the side wall 94 or 112 merges into the side wall sections 96, 98 or 114, 116. The hub 82 has a snap hook 124 on the edge section facing away from the brush head 61, which engages over a nose 126 formed on the drive pin 74.

[0058] The hub 82 and the drive pin 74 can also be manufactured as a single-piece component by means of an injection-molded pin 4. The pin 4 then preferably also forms the toothing of the bevel gear segment 76. List of reference symbols

[0059] 2Holding part 4Pin 6Disk 8Bristle bundle 10Support part 12Through hole 14Thickening 16Surface 18Gap 20Spacer 22Nozzle 24Plastic injected into the gap 18 26Widered part 28Locking edge, widened part of the brush head SPivot axis 30Collar 32Soft-elastic cleaning element 34Soft-elastic cleaning element 36Soft-elastic cleaning element 38Thickening 40Thickening 50Toothbrush 52Handle 54Attachment 56Accumulator 58Electric motor 60Reversing device 61Brush head 62Switch 66Hollow support tube 64Shaft 70Coupling means 72Bevel gear 74Drive pin 76Bevel gear segment 78Bevel gear segment 82Hub 86Underside 90Sleeve-shaped recess 92Axis of rotation or axis of symmetry 94Side wall 96Cylindrical side wall section 98Cylindrical side wall section 100Bottom 102Top 104Center point of the side wall section 98 106Axis of symmetry of the brush head 61 108Groove 110Tone 112Side wall 114Cylindrical side wall sections 116Cylindrical side wall sections 118Tone 120Tone 122Edge area 124Snap hook 126Nose

Claims

1. A brush head for an electrically driven toothbrush having a holding part (2) connected to a carrier part (10) from the surface (16) of which at least a bristle bundle (8) formed by bristle filaments and a resiliently soft cleaning element (32, 34, 36) project, characterized in that said carrier part (10) comprises passage bores (12), that said bristle bundle (8) and said resiliently soft cleaning element (32, 34, 36), respectively, project through one of said passage bores (12) and are fixed in a positive-fit manner relative to said carrier part (10) by way of a thickened portion (14) formed by said filament material or a thickened portion (38, 40) formed by said resiliently soft material.

2. The brush head according to claim 1, characterized in that said thickened portion (14, 38, 40) is connected in a positive substance-fit manner to said carrier part (10).

3. The brush head according to any one of the preceding claims, characterized in that said thickened portion (14, 38, 40) is connected to said carrier part (10) such that an opening on the rear side to said passage bore (12) is closed.

4. The brush head according to any one of the preceding claims, characterized in that said opening on the rear side to said passage bore (12) is closed by filament material or resiliently soft material applied in a molten state against said carrier part (10).

5. The brush head according to any one of the preceding claims, characterized in that several resiliently soft cleaning elements (34, 36) have a common thickened portion (40) and are thereby connected to each other.

6. The brush head according to any one of the preceding claims, characterized in that said holding part (2) and said carrier part (10) are connected to each other by a body of plastic material (24) introduced in a molten state into a gap (18) between said carrier part (10) and said holding part (2).

7. The brush head according to claim 6, characterized in that said plastic material (24) introduced into said gap (18) circumferentially surrounds said carrier part (10) and / or a plate (6) formed by said holding part (2), in particular underlaps or overlaps said plate (6) and / or said bristle carrier.

8. The brush head according to one of claims 6 and 7, characterized in that said carrier part (10) and / or said holding part (2) forms at least one spacer (20) defining said gap.

9. The brush head according to any one of the preceding claims characterized by a connecting element for mechanically coupling said brush head to an electric drive of said electrically driven toothbrush.

10. An attachment part for an electric toothbrush comprising a sleeve member, a drive shaft provided therein which can be coupled to a drive of said electric toothbrush, and a brush head according to anyone of claims 1 to 8 coupled to said drive shaft.

11. A method for manufacturing a brush head for an electrically driven toothbrush having a holding part (2) which is connected to a carrier part (10), from the surface of which at least a bristle bundle (8) formed by bristle filaments and a resiliently soft cleaning element (32, 34, 36) project, wherein said carrier part (10) is first prepared as a separate component with passage bores (12), and at least one bristle bundle (8) made of bristle filaments projecting through one of said passage bores (12.1) and at least one resiliently soft cleaning element (32, 34, 36) projecting through said passage bore or one of the other passage bores (12.2) is connected to said carrier part (10) and is fixed by way of a thickened portion (14, 38, 40) formed on said bristle bundle (8) or on said resiliently soft cleaning element (32, 34, 36), respectively, and thereafter said carrier part (10) thus prepared is connected to said holding part (2).

12. The method according to claim 11, characterized in that said thickened portion (14) formed from said filament material and / or said thickened portion (38, 40) formed from said resiliently soft material is sealingly applied in a molten state against an opening on the rear side to said passage bore (12.1, 12.2).

13. The method according to one of claims 11 and 12, characterized in that said carrier part (10) is stuffed with a prefabricated resiliently soft element (32).

14. The method according to any one of claims 11 to 13, characterized in that said resiliently soft material for forming said resiliently soft element (32, 34, 36) is injected in a molten state through said passage bore (12.2).

15. The method according to any one of claims 11 to 14, characterized by a hot-forming step, in which bristle bundles (8) and / or a preform of a resiliently soft cleaning element (32, 34, 36) after insertion into the associated passage bore (12.1, 12.2) is heated at its end on the attachment side for forming said thickened portion (14, 38, 40).

16. The method according to any one of claims 11 to 15, characterized in that at least one resiliently soft cleaning element (32, 34, 36) and a bristle bundle (8) are provided in combination in a single passage bore (12.1, 12.2).

17. The method according to claim 16, characterized in that said at least one resiliently soft cleaning element (32, 34, 36) and said bristle bundle (8) are both heated at the attachment side for forming a combined thickened portion.