Attachment for an oral care device handle

Abstract

Oral care device attachment (10, 100I) for coupling with a drive shaft of an oral care device handle (20), which has a substantially cylindrical drive shaft coupling end (330), wherein the attachment comprises: an outer attachment tube (11, 110I) with a coupling end designed for attachment to the oral care device handle; a carrier (12, 120I) which is mounted on the outer extension tube (110, 110I) for a driven movement; a motion transmitter (140, 140I) arranged inside the outer attachment tube, the motion transmitter having a first end coupled to the support (12, 120I) and a second end arranged to be coupled to the substantially cylindrical drive shaft coupling end (330), the second end having a coupling unit (200, 200I) having only a cover plate with a flat coupling surface (215I) arranged to be biased against a flat coupling surface of the substantially cylindrical drive shaft coupling end (330) when the oral care device attachment is attached to the oral care device handle; wherein a spring (250I) is arranged between the outer extension tube (110, 110I) and the motion transmitter (140, 140I) such that the motion transmitter is biased into a position in the direction of the coupling end of the outer extension tube.

Description

AREA OF INVENTION

[0001] The present disclosure relates to an oral care device attachment for coupling with a drive shaft of an oral care device handle, which has a substantially cylindrical drive shaft coupling end. BACKGROUND OF THE INVENTION

[0002] It is known that a drive shaft of the handle of an oral care device, such as an electric toothbrush, can be coupled by magnetic attraction to a motion transmitter located in an oral care device attachment, such as a replacement brush head, particularly when the drive shaft generates a linear oscillation. The motion transmitter can be coupled to a carrier attached to an outer tube housing of the attachment, such that the carrier is set into an oscillating rotation about an axis of rotation when the linear oscillation of the drive shaft is transmitted to the carrier by the motion transmitter. Such magnetic coupling avoids wear-prone mechanical coupling components and serves to transmit the linear oscillation in a quiet manner, since the magnetic attraction holds the coupling partners together.Since the magnetic coupling partners only need to connect to each other at their axial surfaces, the distance between, for example, the drive shaft coupling end and a housing of the oral care device handle can be relatively small, for example with a circumferential distance or gap of less than 1 mm, which makes the entire coupling area less bulky than in other designs. Such a coupling concept is described, for example, in document EP 2 550 938 B1.

[0003] However, magnetic coupling requires, for example, a magnet in the coupling end of the drive shaft of the oral care device handle and another magnet or magnetizable element in the respective coupling end of the motion transmitter located in the attachment. These components make the coupling relatively expensive.

[0004] There is therefore a need to provide a more cost-effective coupling between an essentially cylindrical coupling end of a drive shaft of an oral care device handle and a motion transmitter of an attachment for the oral care device handle, which still allows a small circumferential gap between the coupling end of the drive shaft and a housing of the oral care device handle. BRIEF SUMMARY OF THE INVENTION

[0005] According to at least one aspect, an oral care device attachment is provided for coupling with a drive shaft of an oral care device handle, the attachment having a substantially cylindrical drive shaft coupling end, the attachment comprising an outer attachment tube with a coupling end intended to be attached to the oral care device handle, a support attached to the outer attachment tube for driven motion, a motion transmitter arranged within the outer attachment tube, the motion transmitter having a first end coupled to the support and a second end arranged for coupling to the substantially cylindrical drive shaft coupling end, the second end having a coupling unit comprising only a top plate with a flat coupling surface structured in such a way as tothat it is biased against a flat coupling surface of the substantially cylindrical drive shaft coupling end when the oral care device attachment is fitted to the oral care device handle, wherein a spring is arranged between the outer attachment tube and the actuator such that the actuator is biased into a position towards the coupling end of the outer attachment tube.

[0006] The claimed items are defined in the independent claims.

[0007] Further aspects are provided by the features of the dependent claims, whereby it is understood that all features of the dependent claims can be combined with any of the independent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The present disclosure is further explained by a detailed description of exemplary embodiments and with reference to figures. The figures show Fig. 1. A representation of an oral care device designed as an electric toothbrush; Fig. 2. A representation of an interchangeable oral care attachment for an oral care device, wherein the attachment is designed as a toothbrush head; Fig. 3 a cross-section through a coupling section between an oral care handle and an interchangeable oral care attachment, as known from the prior art; Fig. 4A a cross-sectional view of a first example of an oral care device attachment as proposed in accordance with the present disclosure; Fig. 4B a representation of a section of a motion transmitter and a coupling unit provided at a second end of the motion transmitter according to the first example; Fig. 4C a cross-section through the in Fig. 4A shows the attachment in a state in which the motion transmitter is coupled to a drive shaft of an oral care device handle; Fig. 4D a perspective representation of parts of the in Fig. 4A shown in the essay - which also includes one in Fig. 4A shows the omitted mechanical connector - with the outer extension tube only indicated; Fig. 5A a cross-sectional view of a second example of an oral care device attachment as proposed in the present disclosure; Fig. 5B a representation of a section of a motion transmitter and a coupling unit provided at a second end of the motion transmitter according to the second example; Fig. 6A a cross-sectional view of a third example of an oral care device attachment as proposed in accordance with the present disclosure; Fig. 6B a representation of a section of a motion transmitter and a coupling unit provided at a second end of the motion transmitter according to the third example; Fig. 7A a cross-sectional view of a fourth example of an oral care device attachment as proposed in accordance with the present disclosure; Fig. 7B a representation of a section of a motion transmitter and a coupling unit provided at a second end of the motion transmitter according to the fourth example; Fig. 8A a cross-sectional view of a fifth example of an oral care device attachment as proposed in the present disclosure; Fig. 8B a representation of a section of a motion transmitter and a coupling unit provided at a second end of the motion transmitter according to the fifth example; Fig. 9A a cross-sectional view of a sixth example of an oral care device attachment as proposed in accordance with the present disclosure; Fig. 9B a representation of a section of a motion transmitter and a coupling unit provided at a second end of the motion transmitter according to the sixth example; Fig. 10A a cross-sectional view of a seventh example of an oral care device attachment as proposed in accordance with the present disclosure; Fig. 10B a representation of a section of a motion transmitter and a coupling unit provided at a second end of the motion transmitter according to the seventh example; Fig. 11A a cross-sectional view of an eighth example of an oral care device attachment as proposed in the present disclosure; Fig. 11B a representation of a section of a motion transmitter and a coupling unit provided at a second end of the motion transmitter according to the eighth example; Fig. 12A a cross-sectional view of a ninth example of an oral care device attachment as proposed in the present disclosure; Fig. 12B a representation of a section of a motion transmitter and a coupling unit provided at a second end of the motion transmitter according to the ninth example; Fig. 13A a cross-sectional view of a tenth example of an oral care device attachment as proposed in accordance with the present disclosure; Fig. 13B a ​​representation of a section of a motion transmitter and a coupling unit provided at a second end of the motion transmitter according to the tenth example; and Fig. 14 a perspective view of an upper end of an oral care handle comprising an essentially cylindrical drive shaft coupling end and a drive shaft housing. DETAILED DESCRIPTION OF THE INVENTION

[0009] According to the present disclosure, solutions are proposed for coupling an oral care device attachment to an oral care device handle, which has a drive shaft with a substantially cylindrical drive shaft coupling end. The drive shaft is arranged to provide a linear vibration, i.e., an oscillating motion of the drive shaft along its longitudinal axis.The substantially cylindrical drive shaft coupling end can (a) have a diameter in the range of 4 mm to 8 mm, preferably about 6 mm, such as 6.2 mm, (b) have a relatively small circumferential distance to a section of a housing of the handle that encloses the substantially cylindrical drive shaft coupling end, wherein the circumferential gap or distance can be less than about 1 mm, preferably less than about 0.8 mm, further preferably in the range of about 0.6 mm, and / or (c) have at least one indentation or circumferential groove or continue with a smaller diameter. The circumference can be non-constant, i.e., the housing that encloses the substantially cylindrical drive shaft coupling end can have a non-circular cross-section or be arranged non-coaxially with the substantially cylindrical drive shaft coupling end.This can mean that the circumferential gap has a gap width of approximately 0.6 mm in at least one area and, for example, a gap width of 1.0 mm in another area. The gap width is to be understood as being measured in a plane perpendicular to a longitudinal axis of the substantially cylindrical drive shaft coupling end. Furthermore, the substantially cylindrical drive shaft coupling end can have a length extending along the longitudinal axis in the range of 4 mm to 20 mm, preferably in the range of 8 mm to 16 mm, and more preferably of approximately 14 mm, for example, 13.8 mm.

[0010] Fig. Figure 1 is a representation of an exemplary oral care device 1 comprising an oral care device attachment 10 (hereinafter also referred to simply as the "attachment") and an oral care device handle 20 (hereinafter also referred to simply as the "handle"). The attachment 10 comprises an outer attachment tube or housing 11, a carrier 12 mounted on the outer attachment tube 11 for a driven oscillating rotation, as indicated by the double arrow R (although the attachment proposed here is not limited to comprising carriers that are set into an oscillating rotation). Oral care elements 13 are mounted on the carrier 12. The handle comprises a housing 21. The attachment 10 is detachably attached to the handle 20; preferably, the outer attachment tube 11 is mechanically fixed to the housing 21 of the handle 20 such that the outer attachment tube 11 and the housing 21 do not move relative to each other when attached.As will be explained in more detail later, a drive shaft of the handle 20 is detachably connected to a motion transmitter arranged in the outer attachment tube 11, so that a movement provided by the drive shaft (typically a linear oscillation along a longitudinal direction) is transmitted during operation by the motion transmitter to the carrier 12. The oral care device 1 is shown here as an electric toothbrush, the attachment 10 as a replaceable brush head, and the oral care elements 13 as bristle tufts.

[0011] Fig. Figure 2 shows an exemplary attachment 10A, shown in isolation. The attachment 10A comprises an outer attachment tube or housing 11A, a carrier 12A mounted on the outer attachment tube 11A for driven movement, and a plurality of oral care elements 13A mounted on the carrier 12A.

[0012] Fig. Figure 3 is a cross-section through an upper section of an oral care device 1B, comprising an attachment 10B which is detachably mounted on a handle 20B (only partially shown) having a housing 21B, which is only indicated here. The attachment 10B and the handle 20B generally extend along a longitudinal axis L, which here coincides with a central axis of a drive shaft 31B of the handle 20B.

[0013] The cross-section shows an oral care device 1B, as generally described, for example, in document EP 2 550 940 B1. In the oral care device 1B, a motion transmitter 13B is coupled at a first end to a carrier 12B, the carrier 12B supporting a plurality of oral care elements 13B and mounted on an outer attachment tube 11B of the attachment 10B for driven rotation about an axis 15B, i.e., about a rotation axis defined by the axis 15B. The motion transmitter 13B comprises at a second end a first magnetically interacting element 14B and is detachably coupled to a substantially cylindrical drive shaft coupling end 30B.The substantially cylindrical drive shaft coupling end 30B includes a second magnetically interacting element 32B, which magnetically interacts with the first magnetically interacting element 14B, such that both magnetically interacting elements 14B and 32B remain essentially in contact during normal operation when the drive shaft 31B provides a linear reciprocating motion along the longitudinal axis L. The magnetic interaction is achieved by each of the magnetically interacting elements 14B and 32B being designed as a magnet, or by one being designed as a magnet and the other as a magnetizable element. The first magnetically interacting element 14B is attached to the second end of the motion carrier 13B, and the second magnetically interacting element 32B is part of the substantially cylindrical drive shaft coupling end 30B.It may be preferred to design the second magnetically interacting element 32B as a magnet and the first magnetically interacting element 14B as a magnetizable element, since the attachment 10B is typically intended as a disposable part. The essentially cylindrical drive shaft coupling end 30B is here formed by a cap 34B, for example a metal cap, in which the second magnetically interacting element 32B, which may be a cylindrical magnet, for example a cylindrical NdFeB magnet, is attached to the cap 34B by means of an adhesive 33B and is also attached to the drive shaft 31B by means of the adhesive 33B. The essentially cylindrical drive shaft coupling end 30B has a diameter d and a length l, as shown in [reference]. Fig. 3. Possible values ​​for the diameter d and the length l were discussed in a previous paragraph. An undercut may be provided below the substantially cylindrical drive shaft coupling end 30B, i.e., at the lower end facing the handle 20B, since the drive shaft 31B may be smaller in diameter than the substantially cylindrical drive shaft coupling end 30B. Thus, in the present application, the term "undercut" means a section below the substantially cylindrical drive shaft coupling end that is smaller in diameter than the substantially cylindrical drive shaft coupling end itself, and that may be smaller in all directions or only in one or more regions distributed around the circumference.The attachment 10B includes a coupling end comprising a first mechanical connector 16B, which is detachably coupled to a second mechanical connector 26B of the handle 20B, so that the outer attachment tube 11B and a drive shaft housing 22B are positionally fixed to one another. The first and second mechanical connectors 16B and 26B can be mechanically coupled to each other by means of mechanical coupling elements, such as flexible snap hooks, as is generally known in engineering. The drive shaft 31B can be sealed against a cavity in the drive shaft housing 22B by means of a seal 35B, so that no liquids can penetrate into the cavity.

[0014] The following describes ten exemplary embodiments of oral care device attachments according to the present disclosure. All attachments, with the exception of the tenth exemplary attachment, comprise a coupling unit with a cover plate and either (a) an at least partially deformable, substantially cylindrical wall element which, together with the cover plate, defines a receiving cylinder suitable for receiving a substantially cylindrical drive shaft coupling end of a drive shaft from an oral care device handle, or (b) at least two elastic or deflectable or pivotable wall elements which define a substantially cylindrical receiving volume or a substantially cylindrical receptacle for receiving the substantially cylindrical drive shaft coupling end.There are at least three further aspects that are considered in the exemplary implementations, whereby these aspects can be implemented individually or together, i.e., two of the three aspects together or all three aspects together. These three additional aspects are: (1) A spring arranged between the outer extension tube and the motion transmitter, such that the second end of the motion transmitter, that includes the coupling unit, is biased in the direction of the coupling end of the attachment, or, in other words, is in an attached state and is pre-tensioned against the essentially cylindrical drive shaft coupling end during the installation process. (2) A separable mechanical coupling between the coupling unit and the rest of the motion transmitter, so that the coupling unit can be regarded as an adapter which can be fitted onto the substantially cylindrical drive shaft coupling end and can remain there when the rest of the attachment is removed. (3) At least one projection provided on the deformable, substantially cylindrical wall element or on at least one of the at least two elastic or deflectable or pivotable wall elements, and which is suitable to interact with a receptacle or undercut of the substantially cylindrical drive shaft coupling end.

[0015] Possible material choices for the execution of the at least one at least partially deformable, essentially cylindrical wall element made of a thermoplastic elastomer or a natural rubber include, without limitation, one of the following materials: thermoplastic elastomer (TPE), nitrile rubber (NBRs), silicone rubber, EPDM rubber, styrene-butadiene rubber (SBR).

[0016] Possible material choices for manufacturing the at least partially deformable, essentially cylindrical wall element, or the at least two elastic or deflectable wall elements, from a thermoplastic material include, without limitation, one of the following materials: polypropylene (PP), polyamide (PA), polyoxymethylene (POM), acrylonitrile butadiene styrene (ABS), thermoplastic elastomer (TPE) such as Hytrel, or polybutylene terephthalate (PBT). The same materials may be chosen for the cover plate if the cover plate, or a portion thereof, is to be made of a thermoplastic material.

[0017] Possible material choices for the fabrication of the at least partially deformable, essentially cylindrical wall element, or the at least two elastic or deflectable wall elements, from sheet metal include, without limitation, one of the following materials: stainless steel, for example, with material numbers 1.4301, 1.4303, 1.4305, 1.4306, 1.4307, 1.4310 according to standard EN 10027-2, and other corrosion-resistant steels or other metals suitable for producing thin foils with good elastic properties, preferably designated as food-grade materials. Other metallic materials such as molybdenum, titanium, or alloys may also be used, but tend to be more expensive. The same materials may be selected for the cover plate if the cover plate, or a part thereof, is to be made of metal.

[0018] Fig. Figures 4A to 4D show a first example of an essay proposed herein 100. Fig. 4A is a cross-section through the attachment 100, Fig. 4B is a perspective view of a detail showing the second end of a motion transmitter 140 with a coupling unit 200, Fig. 4C is a cross-section through a lower section of the attachment 100 and a drive shaft 22 with a substantially cylindrical drive shaft coupling end 30, and Fig. 4D is a perspective and partially transparent view of an attachment 100', which further comprises a first mechanical connector 300, which is in Fig. 4A has been omitted. Identical features of attachment 100 and 100' are marked with the same reference symbols.

[0019] The in Fig. The attachment 100 shown in Figure 4A comprises an outer attachment tube 110 and a motion transmitter 140, which is arranged in a cavity of the outer attachment tube 110. The motion transmitter 140 has a first end that is coupled to a carrier 120, which carries oral cleaning elements 130 and is arranged for driven movement relative to the outer attachment tube 110. The attachment 100 has a lower end with an opening 111 to allow the attachment 100 to be coupled to a handle of an oral care device, wherein, in particular, a drive shaft of the handle enters the cavity via the opening 111 to establish a connection with a second end or coupling end of the motion transmitter 140, the coupling end of the motion transmitter 140 comprising a coupling unit 200.

[0020] The coupling unit 200 comprises a cover plate 210 and an at least partially deformable, essentially cylindrical wall element 220, which defines a virtual receiving cylinder 251 for receiving an essentially cylindrical drive shaft coupling end of a drive shaft of a handle of an oral care device - see Fig. 4C. The lower end of the attachment 100 typically includes a first mechanical connector 300, which is inserted into the Fig. 4A and Fig. 4C omitted, in Fig. However, it is shown in 4D.

[0021] Fig. Figure 4B shows the lower section of the motion carrier 140, where "lower" refers to the second end of the motion carrier 140, which includes the coupling unit 200. The motion carrier 140 has a first section 141 extending towards the first end, which is coupled to the carrier 120 (see Figure 4B). Fig. 4A), and a second section 143, which continues into the coupling unit 200. A pivot point 142 is provided between the first section 141 and the second section 143 of the motion transmitter 140 to compensate for any angular misalignment between the first and second sections 141, 143 of the motion transmitter 140 during operation. The pivot point 142 is designed here as a film hinge. The coupling unit 200 includes the cover plate 210, which is an integral part of the motion transmitter 140, and the entire integral part can be manufactured by plastic injection molding. The at least partially deformable cylindrical wall element 220 includes a slot 221 that extends from a lower end to the height of the cover plate 210 to make the wall element 220 at least partially deformable due to its elastic properties. The at least partially deformable cylindrical wall element 220 can be made of thin, bent sheet metal, e.g.The metal sheet can have a thickness between 50 micrometers and 500 micrometers, preferably between 75 micrometers and 250 micrometers, such as 75 micrometers, 100 micrometers, 125 micrometers, 150 micrometers, 175 micrometers, 200 micrometers, 225 micrometers, or 250 micrometers. These thickness values ​​generally apply to all embodiments that include a metal sheet component. The at least partially deformable cylindrical wall element 220 can be connected to the cover plate 210 by at least one, preferably at least two, riveted projections 211 extending from the cover plate 210. This does not preclude the wall element 220 from being attached to the cover plate 210 by other or additional techniques, such as (laser) welding, bonding, riveting, screwing, etc.Alternatively or additionally to the slot 221, the wall element 220 can include a slot 222, indicated by dashed lines, which can extend along the entire length of the wall element 220. The coupling unit 200 includes a receiving opening 250 to allow the insertion of the substantially cylindrical drive shaft coupling end into the virtual receiving cylinder 251 (see ). Fig. 4A).

[0022] Fig. 4C shows the same cross-section as in Fig. 4A, but only of a section of the attachment 100 and including an upper section of a drive shaft 31 with a substantially cylindrical drive shaft coupling end 30, which is shown here in a coupled state in which the substantially cylindrical drive shaft coupling end 30 is received in the virtual receiving cylinder 251. As already mentioned in connection with Fig. As discussed in Section 3, the substantially cylindrical drive shaft coupling end 30 can comprise a magnet or magnetizable element 32, a cap 34, and an adhesive 33 that firmly connects the cap 34, the magnet or magnetizable element 32, and the drive shaft 31. It should be noted, however, that the ability to interact magnetically is not important, since the attachments discussed herein are mechanically attached to the substantially cylindrical drive shaft coupling end 30. The substantially cylindrical drive shaft coupling end 30 can therefore also be just a cylinder, for example, a plastic cylinder or a metal cylinder. A section 36 of smaller diameter can extend below the substantially cylindrical drive shaft coupling end 30, such that an undercut is present there, as defined in the preceding paragraph. The Fig. The embodiments shown in Figures 7A to 11B utilize the presence of such an undercut below the substantially cylindrical drive shaft coupling end 30. It should be noted that instead of a smaller diameter section realizing the undercut, a groove or individual recesses may also be provided in the substantially cylindrical drive shaft coupling end 30 to realize the undercut.

[0023] Fig. 4D is a perspective view of a 100' essay, which is essentially the same as the one described in the Fig. 4A and Fig. The attachment 100 shown in Figure 4C is identical, except that the outer attachment tube 110 is shown transparent and a first mechanical connector 300 is arranged at the lower end of the attachment 100', where the term "lower end" refers to the end of the attachment 100' that is intended to be coupled to a handle. The further details in Fig. The elements shown in 4D have already been discussed, and reference is made to the description above. Fig. 4A to 4C referred.

[0024] Fig. Figures 5A to 5B are illustrations of a second example of an essay 100A proposed herein. The elements of this embodiment, which in comparison to the Fig. 4A and Fig. Since sections 4B remain essentially identical, they will not be discussed again (the reference numerals change in the following embodiment, e.g., from 120 to 120A or to 120B, etc.), and only the differences will be highlighted. This also applies to the following description up to and including the Fig. 13A and Fig. 13B. Instead of a film hinge, as discussed for the first embodiment, the second embodiment includes a pivot point 142A, which is realized by a rotary joint with a pivot axis 1421A. The pivot point 142A enables a first section 141A and a second section 143A of a motion transmitter 140A to pivot relative to each other in order to allow a change in the angle between the first section 141A and the second section 143A. The coupling unit 200A comprises a cover plate 210A and an at least partially deformable, substantially cylindrical wall element 220A, which defines a virtual receiving cylinder 251A for receiving a substantially cylindrical drive shaft coupling end of a drive shaft.The cover plate 210A and the second section 143A of the motion transmitter 140A can be made of metal, such as non-magnetic steel, and the partially deformable, essentially cylindrical wall element 220A can in turn be made of non-magnetic, thin sheet metal material and can be connected to the cover plate 210A by laser welding or another metal joining technology, such as gluing, screwing, riveting, etc.

[0025] Fig. Figures 6A to 6B show a third example of an attachment 100B proposed herein. Here, a spring 250B is arranged between a coupling unit 200B and an outer attachment tube 110B, such that the coupling unit 200B is biased towards an opening 111B in a lower end of the attachment 110B. The spring 250B rests at one end against an annular contact surface 112B provided on the inner surface of the outer attachment tube 110B, and at the other end rests against an upper contact surface 212B of a cover plate 210B of the coupling unit 200B. The spring 250B assists in attaching the coupling unit 200B to a substantially cylindrical drive shaft coupling end of a drive shaft in a single attachment operation. The outer extension tube 110B can include an essentially cylindrical inner section 113B which provides a guide for the spring 250B so that the spring cannot bulge or move sideways.The coupling unit 200B comprises the cover plate 210B and an at least partially deformable, substantially cylindrical wall element 220B, which may be made of plastic and which may be designed as an integral part together with a motion transmitter 140B. As discussed with reference to the previous embodiments, the at least partially deformable, substantially cylindrical wall element 220B may include a slot or other cutout 221B that assists the deformation of the at least partially deformable, substantially cylindrical wall element 220B.

[0026] Fig. 7A and Fig. Figure 7B shows a fourth example of an attachment 100C proposed herein. The attachment 100C comprises a coupling unit 200C, which bears some resemblance to a secondary closure for champagne bottles. The coupling unit 200C has two deflectable or pivotable wall elements 2210C and 2220C, which are mounted on a cover plate 210C of the coupling unit 200C. The two deflectable wall elements 2210C and 2220C are each deflectable or pivotable about an axis 225C, i.e., about an axis defined by the axis 225C, against a restoring spring force. In their rest position, the two deflectable wall elements 2210C and 2220C enclose a virtual receiving cylinder 251C for receiving a substantially cylindrical drive shaft coupling end of a drive shaft. Each of the two deflectable wall elements 2210C and 2220C includes a spring extension 2211C and 2220C, respectively.2221C, each bearing against a contact surface 1431C of a second section 143C of a motion carrier 140C, although this is not to be considered a limitation and the restoring spring force can also be provided in another way. If one of the two deflectable wall elements 2210C or 2220C is deflected substantially radially outwards about the axis 225C, the respective spring extension 2211C or 2221C is pressed against the second section 143C of the motion carrier 140C and deforms elastically, thereby generating a restoring spring force that pushes the deflected wall element 2210C or 2220C back into its rest position. In the embodiment shown, each of the two deflectable wall elements 2210C and 2220C comprises a cutout 2212C or 2222C, respectively, provided at a lower end, and each comprises a radially inwardly extending projection 2213C or 2223C, respectively.The projections 2213C and 2223C can be formed as an integral part of the respective deflectable wall element 2210C and 2220C on which they are provided. For example, the wall elements 2210C and 2220C can be made of thin sheet metal material, and the projections 2213C and 2223C can be made of a rolled, folded, or bent piece of sheet metal material, as shown in [reference]. Fig. 7B specified. When a substantially cylindrical drive shaft coupling end enters the virtual receiving cylinder 251C, the projections 2213C and 2223C push the two deflectable wall elements 2210C and 2220C radially outward, causing them to pivot about the axis 225C until the projections 2213C and 2223C engage in an undercut, such as a smaller diameter section under the substantially cylindrical drive shaft coupling end or a groove or receptacle provided in the substantially cylindrical drive shaft coupling end.

[0027] Fig. 8A and Fig. Figure 8B shows a fifth example of an attachment 100D proposed herein. The attachment 100D comprises a coupling unit 200D, which includes two deflectable wall elements 2210D and 2220D that define a virtual receiving cylinder 251D. In contrast to the fourth embodiment, the two deflectable wall elements are not arranged to pivot about an axis, but are arranged to deflect or bend due to the elasticity of the material from which they are made, for example, they may be made of sheet metal. A cover plate 210D of the coupling unit 200D and a motion transmitter 140D are an integral part that can be manufactured by plastic injection molding. The two deflectable wall elements 2210D and 2220D can be connected to the cover plate 210D by means of one or more riveted projections 211D or other techniques, as already described in relation to Fig. 4B explained. Furthermore, the two deflectable wall elements 2210D and 2220D each comprise a radially inwardly extending projection 2213D and 2223D, respectively. The projections 2213D and 2223D can be produced by punching or bending. For clarity, it should be noted that although the projections 2213D and 2223D in this embodiment are produced differently than the projections discussed in relation to the fourth embodiment, this is not to be understood as a limitation. All possibilities for producing the projections can be used interchangeably in all embodiments in which projections are used, and in particular, the two or more projections need not all be produced in the same way.

[0028] Fig. 9A and Fig. Figures 9B are illustrations of a sixth example of an essay 100E proposed herein. This embodiment exhibits some similarities to the one described in the Fig. 8A and Fig. The embodiment shown in Figure 8B is similar, except that here a cover plate 210E and two deflectable wall elements 2210E and 2220E, which define a virtual receiving cylinder 251E, are combined into a single integral part, e.g., as a plastic injection-molded part. The integral part can also include a motion transmitter 140E. The two deflectable wall elements 2210E and 2220E can each, in turn, include a radially inwardly extending projection 2213E and 2223E, respectively, which in this embodiment can then be manufactured using the plastic injection molding process.

[0029] Fig. 10A and Fig. Figure 10B shows a seventh example of an attachment 100F proposed herein. The attachment 100F comprises a coupling unit 200, which is detachably coupled to at least one section of a motion transmitter 140F. More precisely, in the embodiment shown, a first section 141F of the motion transmitter 140F terminates with a first separable coupling part 1421F, which is detachably coupled to a second separable coupling part 1422F, and the first and the second separable coupling parts 1421F and 1422F together form a separable joint 142F, which may be designed as a separable ball joint. The first separable coupling part 1421F is designed here as a spherical end section of the first section 141F of the motion transmitter 140F, and the second separable coupling part 1422F comprises several flexible arms that define a spherical receiving volume that can receive the spherical end section.The coupling unit 200F is integrally designed here with the second separable coupling part 1422F and a second section 143F of the motion transmitter 140F, so that together they form a separable adapter 400F, and the adapter 400F can be manufactured as a plastic injection-molded part. The coupling unit 200F comprises two deflectable wall elements 2210F and 2220F, which define a virtual receiving cylinder 251F, and each of the two deflectable wall elements 2210F and 2220F includes a radially inwardly extending projection 2213F and 2223F, respectively, which can be structured to allow only a single attachment to an essentially cylindrical drive shaft coupling end by engaging in an undercut. Once attached to the substantially cylindrical drive shaft coupling end, the coupling unit 200F can only be removed by destroying the projections 2213F and 2223F.Alternatively, the projections 2213F and 2223F can be shaped such that the coupling unit 200F can be removed from the essentially cylindrical drive shaft coupling end only by applying a relatively high force, but without destroying the projections 2213F and 2223F. Such a pull-off force can be significantly higher than the usual forces acting on the adapter 400F during regular operation; for example, the pull-off force can be greater than 15 N, 20 N, or 25 N. In particular, the pull-off force should be set higher than the separation force required to separate the detachable connection 142F.The basic idea is that the integral part, consisting of the coupling unit 200F, the second section of the motion transmitter 143F and the second separable coupling part 1422F, remains attached to the essentially cylindrical drive shaft coupling end, and the rest of the attachment 100F can then be replaced when it is worn or to attach a different attachment that serves a different purpose.

[0030] Fig. 11A and Fig. Figure 11B shows an eighth example of an essay 100G proposed herein. The eighth embodiment is a combination of the one relating to the Fig. 10A and Fig. 10B discussed embodiment and one relating to the Fig. 6A and Fig. Section 6B discussed spring 250G, which relates to the third embodiment. This eighth embodiment is specifically provided because it shows that the various aspects discussed herein can be combined, provided they are not mutually exclusive.

[0031] Fig. 12A and Fig. Figure 12B shows a ninth example of a proposed attachment 100H. This ninth embodiment is a variant of the seventh embodiment with the separable pivot joint 142F, since the ninth embodiment also includes a separable pivot joint 142H. However, instead of two deflectable wall elements, a coupling section 200H of the ninth embodiment comprises a deformable, substantially cylindrical wall element 220H that defines a cylindrical receiving volume 251H. The deformable, substantially cylindrical wall element 220H can be made of an elastomeric material such as synthetic or natural rubber.

[0032] Fig. 13A and Fig. Figure 13B shows a tenth example of an attachment 100I proposed herein. The tenth embodiment differs from all previously discussed embodiments in that it does not include a wall element to define a cylindrical wall element. Instead, a coupling unit 200I comprises only a cover plate 210I with a flat coupling surface 215I, which is structured (or structurally configured) such that it is biased against a flat coupling surface of a substantially cylindrical drive shaft coupling end when the attachment 100I is fitted to a handle. A spring 250I serves to exert the bias force. As already described, the spring 250I is arranged between an annular contact projection on an inner side of an outer attachment tube 110I and the cover plate 210I. The cover plate 210I can be guided through an inner cylindrical section 113I of the outer attachment tube 110I.In addition to what is shown here, the cover plate 210I can include one or more downward-extending alignment projections to establish positional alignment between the flat coupling surface 215I and the coupling surface of the substantially cylindrical drive shaft coupling end. The spring 250I and the spring constant of the spring 250I should be selected such that the flat coupling surface 215I always remains in contact with the coupling surface of the substantially cylindrical drive shaft coupling end. While, during the phase in which the drive shaft moves upward and compresses the spring, a drive force of the handle must work against the spring 250I, this stored energy is released again when the spring support pushes the drive shaft downward. Only plastic deformation of the spring and conversion of motion into heat then cause additional drive losses.This also applies to the other embodiments with a preload spring.

[0033] Fig. Figure 14 is a perspective view of a coupling end of an oral care device handle 320, which comprises a substantially cylindrical drive shaft coupling end 330 and a drive shaft housing 322. As already explained, the drive shaft housing can serve to mechanically receive an outer attachment tube of an oral care device attachment, so that both are detachably coupled to each other. The drive shaft housing 322 has a somewhat elongated cross-sectional shape, e.g., an elliptical or oval shape, so that an inner cavity of the drive shaft housing 322, which receives the substantially cylindrical drive shaft coupling end 330, also has a substantially elongated cross-sectional shape.Preferably, the substantially cylindrical drive shaft coupling end 330 is not arranged coaxially or centrally in the cavity of the drive shaft housing 322, resulting in a gap 323 between the drive shaft housing 322 and the substantially cylindrical drive shaft coupling end 330, which has a non-constant width. As shown in . Fig. As shown in Figure 14, the width of the gap 323 between the substantially cylindrical drive shaft coupling end 330 and the drive shaft housing 322 can be determined in a plane perpendicular to an extension axis of the drive shaft (see axis L in Figure 14). Fig. 3) have a minimum value w1 and a maximum value w2, wherein, in an example, the minimum width w1 may be about 0.6 mm and the maximum width w2 about 1.0 mm. More generally, but still without limitation, the minimum width w1 may be between 0.3 mm and 0.9 mm and the maximum width w2 between 0.6 mm and 2.0 mm. The difference between the minimum width w1 and the maximum width w2 may be at least about 0.1 mm, preferably at least 0.2 mm, and further preferably at least about 0.4 mm. Alternatively or additionally to the eccentric arrangement between the substantially cylindrical drive shaft coupling end 330 and the drive shaft housing 322, the drive shaft housing 322 may have one or more pockets 3221, 3222, 3223 in its inner side wall.The at least one pocket 3221, 3222, 3223 can have a circumferential extent of at least about 10 degrees, preferably at least 20 degrees, more preferably at least about 30 degrees, and even more preferably at least about 45 degrees. In some examples, the circumferential extent can be at least 60 degrees. In some examples, the drive shaft housing 322 can have two, three, four, or five such pockets. In a preferred example, the drive shaft housing 322 has three pockets, as shown in [reference]. Fig. 14 shown, although the in Fig. The dimensions shown in section 14 are only examples. The length of at least one pocket 3221, 3222, 3223 extends along the drive shaft extension axis (see axis L in [reference missing]). Fig. 3) can, without limitation, be at least about 1 mm, preferably at least about 2 mm, more preferably at least about 3 mm, and also preferably less than about 20 mm. The depth of the pockets in the width direction of the gap 323 can be at least about 0.05 mm, preferably at least about 0.1 mm, more preferably at least about 0.15 mm, and even more preferably at least about 0.2 mm.

[0034] The structure of the gap 322 described above, between the substantially cylindrical drive shaft coupling end 330 and the drive shaft housing 320, can be reflected in the dimensions of an at least partially deformable, substantially cylindrical wall element or in at least two elastic or deflectable wall elements, these elements having already been described with reference to many embodiments. This means, for example, that the width of the at least partially deformable, substantially cylindrical wall element can vary in the circumferential direction, utilizing the space provided by the gap. The at least partially deformable, substantially cylindrical wall element can then have a smaller width where the width w1 of the gap 323 is minimal, and a larger width where the width w2 of the gap 323 is maximal.The practically chosen width can depend on the tolerance of the various elements and also on the lateral movement of the essentially cylindrical drive shaft end 330 during operation. The same applies to the width or widths of at least two elastic or deflectable wall elements, whereby at least one of these wall elements may have a greater width than the other. For the strength of the coupling, it may be advantageous to adapt the width of the wall element(s) to the existing gap width. The wall element(s) may also adapt to the geometry defined by the at least one pocket 3221, 3222, 3223, i.e., the wall element(s) may have corresponding thickenings that then project towards the at least one pocket 3221, 3222, 3223 or even extend into it.

[0035] With reference to the description of the in the Fig. 13A and Fig.In the embodiment shown in 13B, the one or more downwardly extending alignment projections for establishing a positional alignment between the flat coupling surface 215I and the coupling surface of the substantially cylindrical drive shaft coupling end can be dimensioned such that they extend into the space provided by the at least one pocket 3221, 3222, 3223, or such that they are at least in positional alignment with the at least one pocket 3221, 3222, 3223, so that the increased width of the gap prevents a collision between the projections and the inner side wall of the drive shaft housing 322.In one example, the drive shaft housing 322 comprises three pockets 3221, 3222, 3223, which are preferably evenly distributed in the circumferential direction, and the oral care device attachment comprises three evenly distributed downward-extending alignment projections in the circumferential direction to establish a positional alignment between the flat coupling surface and the coupling surface of the substantially cylindrical drive shaft coupling end.

[0036] According to one aspect, an oral care device attachment for coupling with an oral care device handle having a substantially cylindrical drive shaft coupling end is proposed, wherein the attachment comprises an outer attachment tube with a coupling end provided for detachable attachment to a housing of the oral care device handle, a support attached to the outer attachment tube for driven movement, a motion transmitter arranged within the outer attachment tube, the motion transmitter having a first end coupled to the support and a second end arranged for coupling to the substantially cylindrical drive shaft coupling end, the second end comprising a coupling unit with a cover plate and an elastic or deflectable wall element extending from the cover plate.wherein the elastic or deflectable wall element includes an inwardly projecting projection.

[0037] The aspect described in the previous paragraph can be arranged such that it is an elastic or deflectable wall element in positional alignment with a maximum gap width between the substantially cylindrical drive shaft coupling end and the drive shaft housing. In such an example, the coupling unit can be at least part of a separable adapter, wherein preferably at least part of the motion transmitter and the separable adapter are coupled by a separable coupling, such as a separable ball joint.This allows the separable adapter to first be inserted with the single elastic or deflectable wall element into the gap region of maximum width until the inwardly projecting protrusion snaps into an undercut of the substantially cylindrical drive shaft coupling end, and then the separable adapter to be rotated to a position in which the single elastic or deflectable wall element passes through a narrower gap region and, due to the lack of available gap width for the solution, cannot easily detach from the substantially cylindrical drive shaft coupling end before the separable adapter is rotated back to a position in which the single elastic or deflectable wall element again extends through the wider gap region. Other elements, such as the preload spring, can also be added to this aspect, as described in this disclosure.

[0038] The present revelation includes the following aspects A to P: A: Oral care device attachment for coupling with an oral care device handle, the latter having a substantially cylindrical drive shaft coupling end, the attachment comprising an outer attachment tube with a coupling end designed to be detachably attached to a housing of the oral care device handle; a carrier attached to the outer attachment tube for driven movement;a motion transmitter arranged inside the outer extension tube, the motion transmitter having a first end coupled to the support and a second end configured for coupling to the substantially cylindrical drive shaft coupling end, the second end comprising a coupling unit with a cover plate and at least one substantially cylindrical wall element extending from the cover plate, or at least two elastic or deflectable wall elements extending from the cover plate, each of the elastic or deflectable wall elements extending over a portion of a virtual receiving cylinder, such that a substantially cylindrical receiving is defined by the cover plate and the one substantially cylindrical wall element, or by the cover plate and the at least two elastic or deflectable wall elements. B: Attachment according to aspect A, wherein the at least partially deformable, essentially cylindrical wall element is made at least partially of a thermoplastic elastomer or a natural rubber. C: Appendix according to aspect A, wherein at least partially deformable, essentially cylindrical wall elements or the at least two elastic or deflectable wall elements are at least partially made of a thermoplastic material. D: Attachment according to aspect C, wherein the cover plate is made of a thermoplastic material, preferably wherein the cover plate and the at least partially deformable, substantially cylindrical wall element or the at least two elastic or deflectable wall elements are formed as a one-piece, integral unit. E: Attachment according to aspect A, wherein the at least partially deformable, substantially cylindrical wall element or the at least two elastic or deflectable wall elements are at least partially made of sheet metal, in particular of non-magnetic sheet metal, preferably wherein the sheet metal has a thickness of no more than about 250 micrometers, more preferably of no more than about 150 micrometers. F: Attachment according to aspect E, wherein the cover plate is made of a thermoplastic material and the at least partially deformable, essentially cylindrical wall element or the at least two elastic or deflectable wall elements are connected to the cover plate by at least one joining technique from the group consisting of welding, snapping, riveting, gluing and / or screwing. G: Attachment according to aspect E, wherein the cover plate is made of metal, in particular a non-magnetic metal, and the at least partially deformable, substantially cylindrical wall element or the at least two elastic or deflectable wall elements are connected to the cover plate by at least one joining technique from the group consisting of welding, snapping, sealing, gluing, screwing and / or overmolding. H: Attachment according to one of aspects A to G, wherein the at least partially deformable, substantially cylindrical wall element or at least one of the at least two elastic or deflectable wall elements comprises an inwardly projecting projection. I: Attachment according to one of aspects A to H, wherein a spring is arranged between the outer attachment tube and the motion transmitter, such that the motion transmitter is biased into a position in the direction of the coupling end of the outer attachment tube. J: Attachment according to one of aspects A to I, wherein at least one of the at least two elastic or deflectable wall elements is pre-tensioned against the motion transmitter in a rest or clamping position by means of a spring which provides a pre-tensioning force, and wherein the pre-tensioned elastic or deflectable wall element is pivotable about a pivot axis when a force is applied to the pre-tensioned elastic or deflectable wall element against the pre-tensioning force, wherein preferably the pre-tensioning spring is designed as a one-piece element together with the pre-tensioned elastic or deflectable wall element. K: Attachment according to one of aspects A to J, wherein the coupling unit is a separable adapter or part of one, preferably wherein at least a part of the motion transmitter and the separable adapter are coupled by a separable coupling, such as a separable ball joint. L: Oral care device comprising an attachment according to one of aspects A to K and an oral care device handle with a substantially cylindrical drive shaft coupling end coupled to the attachment, wherein the attachment is coupled to the substantially cylindrical drive shaft coupling end in such a way that at least a section of the substantially cylindrical drive shaft coupling end is received in the substantially cylindrical receiving socket. M: Oral care device according to aspect L, wherein the attachment is coupled to the substantially cylindrical drive shaft coupling end in such a way that the substantially cylindrical drive shaft coupling end is completely received in the substantially cylindrical receiving recess, wherein preferably an inwardly projecting projection, which is formed on the at least partially deformable, substantially cylindrical wall element extending from the cover plate, or on at least one of the at least two elastic or deflectable wall elements extending from the cover plate, extends below the substantially cylindrical drive shaft coupling end. N: Oral care device according to aspect L or M, wherein there is a circumferential gap of less than about 1 mm, preferably less than about 0.8 mm, more preferably less than about 0.6 mm, between the substantially cylindrical drive shaft coupling end and a section of a housing of the oral care device handle. O: Kit comprising at least one attachment, comprising an outer attachment tube with a coupling end provided for coupling with the oral care device handle, a carrier attached to the outer attachment tube for driven movement, and a motion transmitter arranged inside the outer attachment tube, the motion transmitter having a first end coupled to the carrier and a second end comprising a first side of a separable connector;and an adapter for coupling to a drive shaft of an oral care device handle with a substantially cylindrical drive shaft coupling end and for coupling to the attachment, wherein the adapter comprises a first end with a second side of the separable connection and a second end with a coupling unit having a cover plate and at least one at least partially deformable, substantially cylindrical wall element extending from the cover plate, or at least two elastic or deflectable wall elements, each extending from the cover plate, wherein each of the deflectable wall elements extends over a section of a virtual receiving cylinder, such that a substantially cylindrical receiving container is defined by the cover plate and the one at least partially deformable, substantially cylindrical wall element or by the cover plate and the at least two elastic or deflectable wall elements. P: Oral care device attachment for coupling to a drive shaft of an oral care device handle, the attachment having a substantially cylindrical drive shaft coupling end, the attachment comprising an outer attachment tube with a coupling end designed to be attached to the oral care device handle; a support mounted on the outer attachment tube for driven movement; a motion transmitter arranged within the outer attachment tube, the motion transmitter having a first end coupled to the support and a second end arranged for coupling to the substantially cylindrical drive shaft coupling end, the second end comprising a coupling unit with a cover plate;wherein a spring is arranged between the outer extension tube and the motion transmitter, such that the motion transmitter is biased into a position towards the coupling end of the outer extension tube.

[0039] The dimensions and values ​​disclosed herein should not be understood as being strictly limited to the exact numerical values ​​stated. Instead, unless otherwise specified, each of these dimensions should mean both the stated value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as "40 mm" should mean "about 40 mm". QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 2 550 938 B1

[0002] EP 2 550 940 B1

[0013]

Claims

[1] Oral care device attachment (10, 100I) for coupling with a drive shaft of an oral care device handle (20) which has a substantially cylindrical drive shaft coupling end (330), wherein the attachment has: an outer attachment tube (11, 110I) with a coupling end designed for attachment to the oral care device handle; a carrier (12, 120I) which is mounted on the outer extension tube (110, 110I) for a driven movement; a motion transmitter (140, 140I) arranged inside the outer attachment tube, the motion transmitter having a first end coupled to the support (12, 120I) and a second end arranged to be coupled to the substantially cylindrical drive shaft coupling end (330), the second end having a coupling unit (200, 200I) having only a cover plate with a flat coupling surface (215I) arranged to be biased against a flat coupling surface of the substantially cylindrical drive shaft coupling end (330) when the oral care device attachment is attached to the oral care device handle; wherein a spring (250I) is arranged between the outer extension tube (110, 110I) and the motion transmitter (140, 140I) such that the motion transmitter is biased into a position in the direction of the coupling end of the outer extension tube. [2] Oral care device attachment according to claim 1, wherein the coupling unit is not configured to accommodate a substantially cylindrical drive shaft coupling end. [3] Oral care device attachment according to one of the preceding claims, wherein the coupling unit is free of any wall elements to define a receiving cylinder that receives the substantially cylindrical drive shaft coupling end. [4] Oral care device attachment according to one of the preceding claims, wherein the cover plate is guided by an inner cylindrical section of the outer attachment tube. [5] Oral care device attachment according to one of the preceding claims, wherein the cover plate has one or more downwardly extending alignment projections. [6] Oral care device attachment (10, 100I) for coupling with a drive shaft of an oral care device handle (20) which has a substantially cylindrical drive shaft coupling end, wherein the attachment has: an outer attachment tube (11, 110I) with a coupling end designed for attachment to the oral care device handle; a carrier (12, 120I) which is mounted on the outer extension tube (110,110I) for a driven movement; a motion transmitter (140, 140I) arranged inside the outer attachment tube, the motion transmitter having a first end coupled to the support (12, 120I) and a second end arranged to be coupled to the substantially cylindrical drive shaft coupling end (330), the second end having a coupling unit (200, 200I) having only a cover plate with a flat coupling surface (215I) arranged to be biased against a flat coupling surface of the substantially cylindrical drive shaft coupling end when the oral care device attachment is attached to the oral care device handle; wherein a spring (250I) is arranged between the outer extension tube (11, 110I) and the motion transmitter (140, 140I) such that the motion transmitter is biased into a position in the direction of the coupling end of the outer extension tube; the coupling unit (200, 200I) is not designed to accommodate a substantially cylindrical drive shaft coupling end. [7] Oral care device attachment (10, 100I) for coupling with a drive shaft of an oral care device handle (20) which has a substantially cylindrical drive shaft coupling end (330), wherein the attachment has: an outer attachment tube (11, 110I) with a coupling end designed for attachment to the oral care device handle; a carrier (12, 120I) which is mounted on the outer extension tube (11, 110I) for a driven movement; a motion transmitter (140, 140I) arranged inside the outer attachment tube, the motion transmitter having a first end coupled to the support (12, 120I) and a second end arranged to be coupled to the substantially cylindrical drive shaft coupling end (330), the second end having a coupling unit (200, 200I) having only a cover plate with a flat coupling surface (215I) arranged to be biased against a flat coupling surface of the substantially cylindrical drive shaft coupling end when the oral care device attachment is attached to the oral care device handle; wherein a spring (250I) is arranged between the outer extension tube (11, 110I) and the motion transmitter (140, 140I) such that the motion transmitter is biased into a position in the direction of the coupling end of the outer extension tube; wherein the coupling unit (200, 200I) is free of any wall elements (220) to define a receiving cylinder which receives the substantially cylindrical drive shaft coupling end (330). [8] Oral care device attachment (10, 100I) for coupling with a drive shaft of an oral care device handle (20) which has a substantially cylindrical drive shaft coupling end (330), wherein the attachment has: an outer attachment tube (11, 110I) with a coupling end designed for attachment to the oral care device handle; a carrier (12, 120I) which is mounted on the outer extension tube (11, 110I) for a driven movement; a motion transmitter (140, 140I) arranged inside the outer attachment tube, the motion transmitter having a first end coupled to the support (12, 120I) and a second end arranged to be coupled to the substantially cylindrical drive shaft coupling end (330), the second end having a coupling unit (200, 200I) having only a cover plate with a flat coupling surface (215I) arranged to be biased against a flat coupling surface of the substantially cylindrical drive shaft coupling end when the oral care device attachment is attached to the oral care device handle; wherein a spring (250I) is arranged between the outer extension tube (11, 110I) and the motion transmitter (140, 140I) such that the motion transmitter is biased into a position in the direction of the coupling end of the outer extension tube; wherein the coupling unit (200, 200I) has only a cover plate with the flat coupling surface (215I), without a cylindrical wall element (220) projecting from it. [9] Oral care device (1) comprising an oral care device attachment (10, 100I) according to one of the preceding claims and an oral care device handle (20) with a substantially cylindrical drive shaft coupling end (330) having a flat coupling surface coupled to the oral care device attachment, wherein the oral care device attachment is coupled to the oral care device handle by pre-tensioning the flat coupling surface of the cover plate with the flat coupling surface of the substantially cylindrical drive shaft end, wherein a drive shaft comprising the substantially cylindrical drive shaft end is arranged to provide an oscillating movement of the drive shaft along its longitudinal axis.

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