Field of invention

The invention relates to a dividable dental care product, such as a toothbrush. The invention also relates to a head part configured to form part of a dividable dental care product.

The invention also relates to a kit of parts a plurality of head parts configured to form part of a dividable dental care product. Technical Background

When designing a toothbrush, the designer typically takes a plurality of design criteria in consideration. The toothbrush should allow the user to efficiently clean their teeth, the toothbrush should be convenient to produce, the toothbrush should have a limited environmental impact, the toothbrush should be hygienic, the toothbrush should be pleasant to use, and of course the toothbrush should meet current standards concerning e.g., safety requirements related to amongst others the physical design of the toothbrush.

Toothbrushes are today typically formed of a polymer-based material. However, there exist on the market also toothbrushes formed of other materials, such as bamboo-based toothbrushes.

Through-out the years there has also been suggested to design toothbrushes in a two-part design with a handle and a head being separably interconnected to each other.

Different two-part designs are e.g., disclosed in KR 20-2020- 0000359U, WO 01/17433 A1 , W02020/135915A1 , W02020136198A1 ,

DE9318453U1 , EP 2792271 A1 , EP 3827700 A1 , WO 97/35498, and DE20 2019001 011 U1.

KR 20-2020-0000359U discloses a two-part toothbrush with an interface between a head part and a handle part. The interface comprises multiple circular grooves in the head part interacting with multiple circular protrusions of the handle part, wherein rotation of the head part during use is prevented by multiple rotation preventing groove portions and rotation preventing protrusion portions. There is also disclosed an embodiment where the circular grooves are replaced by screw threads.

WO 01/17433 A1 discloses a brush head being screwed into a handle.

W02020/135915A1 and WO2020136198A1 discloses in great detail a design in which a brush head is provided with longitudinally extending grooves allowing the head to be slid onto a correspondingly shaped distal end of a handle. The document also mentions that the head could optionally connected to the handle using threads and just mentions that there should be corresponding internal and external threads.

DE9318453U1 discloses a design where a brush head is stuck into a recess of a handle. It is also mentioned that the parts could be connected to each other in other ways and there is e.g., disclosed that they can be screwed together, or that there can be made use of wedge, cone, tongue or groove connections.

EP 2792271 A1 discloses a concept where disposable brush heads being pre-loaded with dried toothpaste are screwed onto a handle. This document is directed to the concept of having dried toothpaste on the disposable brush heads and provides only few details concerning the mechanical connection between the brush head and handle. However, it is said that the handle is provided with a free end with substantially cylindrical shape and is externally provided with a relief thread. From the disclosure is seems like that the disposable brush head is to be screwed onto the handle such that the brush head reaches over a portion of the handle and to be screwed onto the handle until the free end of the handle reaches a bottom inside the cylindrical bore in the disposable brush head.

EP 3827700 A1 discloses a concept of a separable toothbrush comprising a head unit, a handle unit and a coupling unit.

WO 97/35498 discloses a two-part toothbrush where a head part is snapped in position onto a handle. The head part is rotatably connected to the handle such that different orientations and angles may be achieved. DE20 2019001 011 U1 discloses a head being screwed onto a handle. It discloses that the head is provided with a hygienic connection ring which extends a distance over the handle and that this distance provides a compression between the ring and the handle. This distance and resulting compression forms a sealing surface on the outer envelope surface of the handle and the sealing properties are to a large dependent upon there being a tight fit between the hygienic ring and the handle and that the hygienic ring need to be fairly rigid.

However, the prior art designs all fall short in one or more of the above criteria concerning that the toothbrush should allow the user to efficiently clean their teeth, the toothbrush should be convenient to produce, the toothbrush should have a limited environmental impact, the toothbrush should be hygienic, the toothbrush should be pleasant to use, and of course the toothbrush should meet current standards concerning e.g., safety requirements related to amongst others the physical design of the toothbrush.

Summary of invention

It is an object of the invention to provide a dividable dental care product, such as a tooth brush, addressing at least some of the design criteria that the dental care product should allow the user to efficiently clean their teeth, it should be convenient to produce, it should have a limited environmental impact, it should be hygienic, it should be pleasant to use, and of course it should meet current standards concerning e.g., safety requirements related to amongst others the physical design of the specific dental care product.

This object has been achieved by a dividable dental care product comprising a base part having a handle portion and an interconnection portion, and a head part having an interconnection portion and a dental care utility portion, wherein the base part and the head part are configured to be separably interconnected by their respective interconnection portion, wherein the interconnection portion of the head part comprises a tubular portion with an internal threading formed on an inwardly facing envelope surface of the tubular portion, wherein the interconnection portion of the base part comprises a protruding portion extending along a longitudinal direction along a central axis from the handle portion towards a free end of the protruding portion, the protruding portion being provided with an external threading formed in an outwardly facing envelope surface of the protruding portion, wherein the protruding portion is configured to be received into the tubular portion by a threading motion about the central axis, wherein the interconnection portion of the base part comprises a shoulder which extends radially outwardly from and circumferentially around the protruding portion and which presents an abutment surface configured to face the head part, wherein the tubular portion is provided with an end surface extending circumferentially around a mouth of the tubular portion, characterised in that the abutment surface of the base part is configured to abut the end surface of the head part when the base part and head part are interconnected to each other in order to form said dividable dental care product, and wherein the internal threading has a root thickness and a thread pitch as measured long the central axis, wherein the thread pitch is at least two times the root thickness.

This general design allows the base part to be used over a period of time and to be interconnected with different head parts, one at the time, during said period of time.

This general design also allows the base part and the head part/-s to be manufactured from different materials.

This general design also makes it possible to e.g., strike a new balance between the use of different materials with different material properties and/or different possible designs of the different parts, and the concept of having different possible life-spans for different parts, and to thereby create a dividable dental care product, such as a toothbrush which addresses the above mentioned criteria in an improved manner.

It may especially be noted that by designing the dividable dental care product such that there is a threaded interconnection in combination with providing a shoulder which extends radially outwardly from and circumferentially around the protruding portion and which presents an abutment surface configured to face the head part, and in combination with the tubular portion being provided with an end surface extending circumferentially around a mouth of the tubular portion, wherein the abutment surface of the base part is configured to abut the end surface of the head part when the base part and head part are interconnected to each other in order to form said dividable dental care product, has been facilitated to provide a design which amongst others meets the hygienic requirements, which is pleasant to use, which is easy to manufacture, and which is easy to assemble. The threading and the provision of the abutment surface and the end surface makes it possible to accomplish a sealingly tight engagement between the two parts. This efficiently removes the need for the provision of any elastomeric sealing ring or the like extending on the outside of the handle as suggested by the prior art. This in turn facilitates production and it makes it easier for the user to assemble the product while still allowing the hygienic requirement to be met. Moreover, the provision of an elastomeric sealing ring protruding outwardly may have a negative impact on how pleasant it is to use the dental care product depending on the actual position of the sealing ring. Thus, the possibility to omit the elastomeric sealing ring, which is used in the prior art designs, opens up for a freer placement of the interconnection. In this context it may be noted that it is preferred that there is no additional part, such as any elastomeric sealing ring, in the interface. It is preferred that the interface is formed by a direct abutment of the end surface against the abutment surface of the base part. This general design also provides an easy assembly and a strong locking effect in that the torque necessary to lock the parts together, and thereby also the torque keeping the parts together, increases sharply when the abutment surface and end surface abuts each other. However, it is sufficient to release the abutment and thereafter the disassembly may be performed effortless. Since the high torque is accomplished over a short length, it is easy for a user to provide a strong locking effect since it is sufficient for the user to provide a short burst of high torque, both when it comes to locking the parts into position and when it comes to releasing them. The abutment between the abutment surface and the end surface provides a strong friction lock.

Root thickness is intended to refer to the thickness of the thread profile, i.e. , the width of the root of the protruding profile as seen in a cross-sectional plane along the central axis and with the root thickness measured along the central axis. In this context root is intended to refer to the part of the actual thread profile connecting to or closest to the internal envelope surface of the tubular portion. It may be noted that the width of the profile refers to the width of the part of the profile actually interacting with the corresponding profile of the other part and is not intended to refer to a width measured at any optional root rounding or root relief. This design allows for a strong threading in combination with a quick and easy assembly of the dental care product by the user. Preferably, the external threading is correspondingly shaped in the sense that the groove has at the corresponding height a corresponding width just capable of receiving the profile of the internal threading to allow for the intended threading interaction between the two interconnection portions.

Thus, in a sense it could also be said that the external threading has a root width and a thread pitch as measured long the central axis, wherein the thread pitch is preferably at least two times the root width. In the preferred embodiment, the profile of the protruding profile of the internal threading and the profile of the groove of the external threading are trapezoid-shaped and the flanks of the profiles abut each other along most and even more preferably along close to the complete height, e.g., the complete height apart from any top rounding.

This general design also makes it possible to form a strong abutment between the abutment surface and the end surface at a maximum available distance from the central axis which in turn strengthens the bending resistance of the interconnection. This in turn opens up the design choices when it comes to using less material and/or when it comes to the location of the interconnection as seen along the central axis.

Thus, the new design disclosed above is compared to the prior art not associated with features which in turn sets specific limitations on the design choices available. On the contrary, the general design disclosed above opens up for a number design choices unachievable, or at least not easily available, in the prior art designs.

As mentioned by way of introduction, the general two-part design allows the user of different materials in different parts, such as the provision of a polymer-based head part and a wood-based base part. However, it may also be noted that the general design also opens up for different choices of material in the sense that in a complete product-line it is possible to have a plurality of different components manufactured from different materials. It is e.g., conceivable that a complete product-line includes a choice concerning to choose a base part manufactured from wood-based material or a base part manufactured from a polymer-based material. The general design with the threading and the end surface abutting the abutment surface allows for a number of different material combinations.

It may be noted that a threading may generally be explained as a helical structure used to convert a rotational movement and torque to a linear movement and axial force. The helical structure may for an internal threading be said to be formed by a structure extending inwardly from an inwardly facing tubular surface and extending along a helix. Alternatively, for an internal threading, the helical structure may be said to be formed by a groove formed in the inwardly facing tubular surface, the groove having a profile extending outwardly into the wall of the tubular portion and along a helix. Sometimes the internal threading is referred to as a set of alternating grooves and protrusions extending along a helix. It may be noted that the different notions used are often associated with the different methods of producing such an internal threading. Due to the geometrical design of the preferred embodiment, we will for clarity reasons, in this description refer to the internal threading as a structure extending inwardly from an inwardly facing tubular surface and extending along a helix. However, it should be noted that this does not imply a specific method of manufacturing such an internal threading. Different methods of manufacturing such an internal threading will be discussed separately below. Analogously, due to the geometrical design of the preferred embodiment, we will for clarity reasons, in this description refer to the external threading as a groove extending inwardly into an outwardly facing envelope surface of the protruding portion and extending along a helix. Analogously, it should be noted that this does not imply a specific method of manufacturing such an external threading. Different methods of manufacturing such an external threading will be discussed separately below.

In a typical use scenario in which the dental care product e.g., is a toothbrush, the user has purchased a kit including one base part and a plurality of head parts. The user attaches one of the head parts to the base part and uses it to brush his/her teeth, rinse it, allows it to dry, and uses it as an ordinary toothbrush daily for a period of time, such as a month or so. This period of time may vary upon the preferences of the user. In this context it may be noted that World Health Organisation, WHO, recommends that toothbrushes are replaced after three months of daily use. Thereafter, the user disassembles the head part from the base part, disposes the used head part and attaches a new head part to the base part. The user might also have a head part forming another kind of dental care product, such as a small pointy brush intended to clean specific parts of the teeth which e.g., could be intended to be used when a need occurs or on a non-daily basis. In such a case, the user might e.g., temporarily remove the head part forming the ordinary toothbrush and temporarily use the base part in combination with the other kind of head part and after that use remove the other kind of head part and reattach the ordinary head part again. Since the general design opens up for a number of design choices when it comes to materials of the different parts and when it comes to the function of the head part, numerous other use scenarios are available. As mentioned above, a strength of the general design is the versatility in design which in turn renders it to form a foundation for a versatile product-line. Other kinds of head parts may e.g., include other designs of the brush section, such as a brush section having significantly softer bristles, a brush section having a narrower brush section, i.e. , smaller width across the central axis, a brush section designed for cleaning braces, a brush section designed for cleaning a prosthesis, etc.

Preferred embodiments appear in the dependent claims and in the description.

It may in this context be noted that it is also conceivable that the dividable dental care product is designed in accordance with the disclosure above but without the feature concerning that the internal threading has a root thickness and a thread pitch as measured long the central axis, wherein the thread pitch is at least two times the root thickness. It may further be noted that it is also conceivable that the dividable dental care product is designed in accordance with the disclosure above but also, or alternatively, without the feature concerning that the interconnection portion of the base part comprises a shoulder which extends radially outwardly from and circumferentially around the protruding portion and which presents an abutment surface configured to face the head part, the tubular portion being provided with an end surface extending circumferentially around a mouth of the tubular portion, and the abutment surface of the base part being configured to abut the end surface of the head part when the base part and head part are interconnected to each other in order to form said dividable dental care product.

Thus, the invention may also be said to relate to a dividable dental care product comprising a base part having a handle portion and an interconnection portion, and a head part having an interconnection portion and a dental care utility portion, wherein the base part and the head part are configured to be separably interconnected by their respective interconnection portion, wherein the interconnection portion of the head part comprises a tubular portion with an internal threading formed on an inwardly facing envelope surface of the tubular portion, wherein the interconnection portion of the base part comprises a protruding portion extending along a longitudinal direction along a central axis from the handle portion towards a free end of the protruding portion, the protruding portion being provided with an external threading formed in an outwardly facing envelope surface of the protruding portion, wherein the protruding portion is configured to be received into the tubular portion by a threading motion about the central axis.

Such a dividable dental care product may be combined with any of the preferred features mentioned below.

It may especially be noted that such a dividable dental care product may be designed such that the dividable dental care product also includes the features that the interconnection portion of the base part comprises a shoulder which extends radially outwardly from and circumferentially around the protruding portion and which presents an abutment surface configured to face the head part, wherein the tubular portion is provided with an end surface extending circumferentially around a mouth of the tubular portion, wherein the abutment surface of the base part is configured to abut the end surface of the head part when the base part and head part are interconnected to each other in order to form said dividable dental care product, and/or the features that the internal threading has a root thickness and a thread pitch as measured long the central axis, wherein the thread pitch is at least two times the root thickness. Also, a dividable dental care product of any of these latter kinds may be combined with any of the preferred features mentioned below.

The abutment surface of the base part is preferably configured to sealingly abut the end surface of the head part when the base part and head part are interconnected to each other in order to form said dividable dental care product. Thereby it is facilitated to provide a design which amongst others meets the hygienic requirements.

The internal threading of the tubular portion and the external threading of the protruding portion may have a trapezoid profile. This profile shape is considered advantageous since it possible to be produced in various materials, including wood and plastic, using various manufacturing methods. This profile shape is also considered appropriate to use since it opens up different design choices, such as the possibility of providing a comparably large thread pitch, the possibility to provide conicity of the different interconnection portions, etc. It is e.g., possible to efficiently produce an external threading in a wood based handle by providing a relative rotation and longitudinal movement between the handle and a squarely shaped cutting tool. Moreover, the trapezoid profile is also capable of providing a strong axial force thereby aiding in making it possible to provide a tight abutment between the abutment surface and the end surface as discussed above.

The internal threading of the tubular portion and the external threading of the protruding portion is preferably a single entry threading. This makes it possible to allow a significant amount of material to be present between each groove forming the external threading. This provides a strong external threading. Such a design is especially suitable when it comes to allowing the base part to be manufactured of a wood-based material.

In the preferred embodiment, the internal threading of the tubular portion and the external threading of the protruding portion is a single entry threading and the internal threading have a root thickness and a thread pitch as measured long the central axis, wherein the thread pitch is at least two times the root thickness.

The inwardly facing envelope surface of the tubular portion may be tapered such that an inner diameter of the inwardly facing envelope surface decreases with increased distance from the mouth of the tubular portion. This is beneficial since it opens up the tolerance window which in turn facilitates the provision of an easy assembly in while still accomplishing a strong final connection.

The tubular portion is preferably tapered such that the inwardly facing envelope surface is angled inwardly a few degrees, i.e. , such that the tubular portion is almost cylindrical. The angle a by which the inwardly facing envelope surface is angled relative to the central axis is preferably between 1- 5 The inwardly facing envelope surface may comprise a non-threaded portion extending from the mouth a distance along the central axis, wherein the distance is preferably at least equal to one times a root thickness of the internal threading. This is advantageous since it allows the provision of a non- threaded portion in the envelope surface of the protruding portion, the non- threaded portion extending from the shoulder a distance along the central axis, wherein the distance is less than or equal to said distance of the non- threaded inwardly facing envelope surface being preferably at least equal to one times a root thickness of the internal threading.

It should be noted that the provision of the non-threaded portion allows, but does not necessitate, the provision of a non-treaded portion in the envelope surface of the protruding portion. Thus, even though the tubular portion is provided with said non-threaded portion, the groove forming the external threading may extend further towards or even all the way to the shoulder.

The provision of a non-threaded portion in the inwardly facing envelope surface may also act as a guide opening facilitating initial assemble of the dental care product.

The protruding portion may comprise a non-threaded portion extending from the shoulder a distance along the central axis, wherein the distance is at least equal to one fifth times a root width of the external threading. This facilitates production thereof in the sense that it facilitates machining of a base part, which e.g., is useful when designing the base part of wood-based material, and it facilitates machining of a moulding tool, which e.g., is useful when designing the base part of a polymer-based material. The non-threaded portion of the inwardly facing envelope surface may thus extend from the mouth a distance along the central axis being at equal to or larger than the non-threaded portion of the protruding portion, i.e. , preferably at least one fifth times a root thickness of the internal threading. In an alternative embodiment, the protruding portion may comprise a non-threaded portion extending from the shoulder a distance along the central axis, wherein the distance is at least equal to one times a root width of the external threading. In one preferred embodiment, the dividable dental care product is a toothbrush, wherein the dental care utility portion comprises a brush section comprising a brush head formed in the head part at an end portion of the head part opposing the tubular portion and a plurality of bristles attached to a transversely oriented surface of the brush head.

A distance along the central axis between a distal end of the brush head and the mouth of the tubular portion may be at least 60mm, preferably between 60mm and 90mm, more preferably between 60mm and 80mm. Alternatively or as a complement thereto, a distance along the central axis between a central position of the brush head and the mouth of the tubular portion may be at least 45mm, preferably between 45mm and 75mm, more preferably between 45mm and 65mm. A central position refers in this context to a central position as seen along the central axis.

This distance is considered suitable since it allows for a sufficient overlap of the interconnection portions and still allows for making efficient use of the fact that the toothbrush is of a two-part design, such as still allowing to make efficient use of the possibility to choose different materials for the different parts.

An outer circumferential envelope surface of the shoulder of the base part is preferably flush with an outer envelope surface of the head part at the mouth of the tubular portion when the base part and head part are interconnected to each other in order to form said dividable dental care product.

This is beneficial in the sense that it makes the dental care product comfortable to use and in the sense that it facilitates keeping the dental care product clean.

The base part may be rotationally symmetrical about the central axis. Such a design facilitates production of the whole baser part and it also facilitates assembly of the product. Moreover, it also opens up the tolerance windows e.g., when it comes to the tolerances applicable to the interconnection portions, the threading and the position of the shoulder, which in turn further facilitates production. In one preferred embodiment, the base part and the head part are formed from different materials. It may be noted that different materials may refer to completely different materials, such as polymer-based material respectively wood-based materials. However, different materials may also refer to different polymer-based materials. The different load conditions of the base part and the head part may e.g., be addressed using a first polymer- based material for the base part and a second, different one, polymer-based material for the head part. It may also be noted that different polymer-based materials may refer to the use of different polymers such as polyethylene respectively polypropylene, but it may also relate to the use of different grades of the same kind of polymer, such as different grades of polyethylene. The different grades may e.g., relate to different average length of the polymer chains, different additives, etc.

The head part may be formed of a polymer-based material. This choice of material is beneficial since it offers a great variety when it comes to design options.

The base part may be formed of a wood-based material. This choice of material is beneficial since it may be environmentally friendly and since it makes it easy to provide a comfortable grip feeling both when it comes to structure and shape.

The base part may be formed of a polymer-based material. This choice of material is beneficial since it offers a great variety when it comes to design options. Also, a polymer-based base part may be hollow, or provided with a recess, and carry electronics providing additional functionality.

It may be noted that also a base part formed of a wood-based material may be hollow or provided with a recess, and carry electronics providing additional functionality.

The above-mentioned object has also been achieved by a head part configured to form part of a dividable dental care product, the head part having an interconnection portion and a dental care utility portion, wherein the head parts is configured to be separably interconnected with its interconnection portion to an interconnection portion of a base part, wherein the interconnection portion of the head part comprises a tubular portion extending around a central axis and being provided with an internal threading formed on an inwardly facing envelope surface of the tubular portion, wherein the tubular portion is provided with an end surface extending circumferentially around a mouth of the tubular portion, characterised in that, the internal threading has a root thickness and a thread pitch as measured long the central axis, wherein the thread pitch is at least two times the root thickness.

The advantages associated with the general design, preferred embodiments thereof, and various variations has been discussed in detail above with reference to a dividable dental care product and that discussion is equally relevant to head part.

The tubular portion is preferably configured to receive the interconnection portion of the base part by a threading motion about the central axis.

The end surface of the head part is preferably configured to abut an abutment surface of the base part facing the end surface of the head part when the base part and the head part are interconnected to each other in order to form said dividable dental care product. The interconnection portion of the base part preferably comprises a shoulder which extends radially outwardly from and circumferentially around the protruding portion and which presents an abutment surface configured to face the head part.

Similarly, as discussed above with reference to the dividable dental care product, it may in this context be noted that it is also conceivable that the head part is designed in accordance with the disclosure above but, similarly as for the dividable dental care product, without the feature concerning that the internal threading has a root thickness and a thread pitch as measured long the central axis, wherein the thread pitch is at least two times the root thickness. It may further be noted that it is also conceivable that the head part is designed in accordance with the disclosure above but also, or alternatively, without the feature concerning the tubular portion being provided with an end surface extending circumferentially around a mouth of the tubular portion.

Thus, the invention may also be said to relate to a head part configured to form part of a dividable dental care product, the head part having an interconnection portion and a dental care utility portion, wherein the head parts is configured to be separably interconnected with its interconnection portion to an interconnection portion of a base part, wherein the interconnection portion of the head part comprises a tubular portion extending around a central axis and being provided with an internal threading formed on an inwardly facing envelope surface of the tubular portion.

Such a head part may be combined with any of the features mentioned above with respect to the preferred embodiments of the dividable dental care product.

It may especially be noted that the head part may be designed such that the head part also includes the features that the tubular portion is provided with an end surface extending circumferentially around a mouth of the tubular portion, wherein the abutment surface of the base part is configured to abut an end surface of the head part when the base part and head part are interconnected to each other in order to form said dividable dental care product, and/or the features that the internal threading has a root thickness and a thread pitch as measured long the central axis, wherein the thread pitch is at least two times the root thickness. Also, a head part of any of these latter kinds may be combined with any of the features mentioned above with respect to the preferred embodiments of the dividable dental care product.

It may in this context also be noted that any of these head parts in accordance with any one of the different preferred embodiments may form part of a kit of parts including a plurality of such head parts. It may be noted that the head parts may be of the same kind or may be of different kinds.

The above-mentioned object has also been achieved by a kit of parts comprising a plurality of head parts each having an interconnection portion and a dental care utility portion, wherein each one of the head parts is configured to one at the time be separably interconnected with its interconnection portion to an interconnection portion of a base part, wherein the interconnection portion of the head part comprises a tubular portion extending around a central axis and being provided with an internal threading formed on an inwardly facing envelope surface of the tubular portion, wherein the tubular portion is configured to receive the interconnection portion of the base part by a threading motion about the central axis, wherein the tubular portion is provided with an end surface extending circumferentially around a mouth of the tubular portion, characterised in that when the base part and the head part are interconnected to each other in order to form said dividable dental care product, the end surface of the head part is configured to abut an abutment surface of the base part facing the end surface of the head part, and wherein the internal threading has a root thickness and a thread pitch as measured long the central axis, wherein the thread pitch is at least two times the root thickness.

The advantages associated with the general design, preferred embodiments thereof, and various variations has been discussed in detail above with reference to a dividable dental care product and that discussion is equally relevant to the kit of parts.

In accordance with one embodiment all the plurality of head parts in the kit of parts are of the same kind and have the same functional properties. They may e.g., all be head parts configured to form a toothbrush and they may e.g., all have the same shape and have bristles of the same design and hardness/rigidity. Thus, from a functional perspective, the head parts are interchangeable. The head parts may all be fully identical or may have different designs when it comes to non-functional features, such as different decors, different colourings, or the like. Such a kit of parts is e.g., useful for a user which is using or is considering to continually be using a two-part toothbrush. The user will typically purchase a new replacement sets including only a plurality of head parts of the desired kind and will re-use the base part. The base part may have been bought separately or e.g., as part of a starter- kit.

In accordance with one embodiment all the plurality of head parts in the kit of parts are of the same kind but have slightly different functional properties. They may e.g., all be head parts configured to form a toothbrush, but the different head parts may have different size and/or shape of the brush head, different size and/or shape of the bristle base section, different size and/or shape of imaginary surface spanned by the bristles top, and/or different hardness and/or rigidity of the bristles. Such a kit of parts is e.g., useful for user which is not certain which kind of brush is the best from him/her. Such a kit may, but need not, include a base part.

It may also be noted that the head parts of the kit of parts need not all have different functional properties. It is e.g., conceivable to have a kit including one or more sub-sets of a plurality of head parts being functionally interchangeable within respective sub-set. Such a kit may optionally also be provided with one or more sub-sets of a single functionally different head part. The set-up may e.g., be that the kit of parts includes one sub-set including a plurality of head parts configured to form a toothbrush, where the bristles e.g., all have a first hardness/rigidity and are considered interchangeable and that the kit of parts also includes one other head part where the bristles e.g., are different, such as being harder/more rigid, and that this one other head part is intended to be used only now and then, such as if something gets stuck or when braces need specific attention. This latter may be said to be a hybrid between the two embodiments mentioned above.

In one embodiment the head parts in the kit of parts are of different kinds. They may all be of different kinds or they may be divided into one or more subsets each including one or more head parts. This may e.g., be embodied in a kit of parts one sub-set including a plurality of head parts configured to form a toothbrush, where the bristles e.g., all have a first hardness/rigidity and are considered interchangeable, and that the kit of parts also includes one other head part of a different kind, such as a completely differently designed brush used for a specific purpose, such as a brush having a pointy brush section capable of reaching areas not easily reachable using a toothbrush having an ordinarily shaped brush section.

As discussed above with reference to the dividable dental care product and with reference to the head part, also the kit of parts may be designed in accordance with the disclosure above but with the respective head part not necessarily including the feature concerning that the internal threading has a root thickness and a thread pitch as measured long the central axis, wherein the thread pitch is at least two times the root thickness.

It may further be noted that it is also conceivable that the kit of part is designed in accordance with the disclosure above but also, or alternatively, without the features concerning that the tubular portion being provided with an end surface extending circumferentially around a mouth of the tubular portion, and the abutment surface of the base part being configured to abut the end surface of the head part when the base part and head part are interconnected to each other in order to form said dividable dental care product.

Thus, the invention may also be said to relate to a kit of parts comprising a plurality of head parts each having an interconnection portion and a dental care utility portion, wherein each one of the head parts is configured to one at the time be separably interconnected with its interconnection portion to an interconnection portion of a base part, wherein the interconnection portion of the head part comprises a tubular portion extending around a central axis and being provided with an internal threading formed on an inwardly facing envelope surface of the tubular portion, wherein the tubular portion is configured to receive the interconnection portion of the base part by a threading motion about the central axis.

Such a kit of parts may be combined with any of the features mentioned above with respect to the preferred embodiments of the dividable dental care product. It may especially be noted that the kit of parts may be designed such that the respective head part also includes the features that the tubular portion is provided with an end surface extending circumferentially around a mouth of the tubular portion, wherein the abutment surface of the base part is configured to abut an end surface of the head part when the base part and head part are interconnected to each other in order to form said dividable dental care product, and/or the features that the internal threading has a root thickness and a thread pitch as measured long the central axis, wherein the thread pitch is at least two times the root thickness. Also, a kit of parts of any of these latter kinds may be combined with any of the features mentioned above with respect to the preferred embodiments of the dividable dental care product. It may be noted that the head parts may be of the same kind or may be of different kinds.

The kit of parts may further comprise a base part having a handle portion and an interface portion.

The interface portion of the base part may comprise a protruding portion extending along a longitudinal direction along a central axis from the handle portion towards a free end of the protruding portion, the protruding portion preferably being provided with an external threading formed on an outwardly facing envelope surface of the protruding portion, wherein the protruding portion preferably is configured to be received into the tubular portion by a threading motion about the central axis.

The interface portion of the base part may comprise a shoulder which extends circumferentially around the protruding portion and which presents said abutment surface configured to face the head part.

Such a kit of parts may also be referred to as a kit of parts comprising a base part having a handle portion and an interface portion, and a plurality of head parts each having an interconnection portion and a dental care utility portion, wherein the base part and each one of the head parts are configured to be separably interconnected by their respective interconnection portions allowing the base part to be used over a period of time and to be interconnected with each of the plurality of head parts, one at the time, during said period of time, wherein the interface portion of the head part comprises a tubular portion with an internal threading formed on an inwardly facing envelope surface of the tubular portion, wherein the interface portion of the base part comprises a protruding portion extending along a longitudinal direction along a central axis from the handle portion towards a free end of the protruding portion, the protruding portion being provided with an external threading formed on an outwardly facing envelope surface of the protruding portion, wherein the protruding portion is configured to be received into the tubular portion by a threading motion about the central axis, wherein the interface portion of the base part comprises a shoulder which extends circumferentially around the protruding portion and which presents an abutment surface configured to face the head part, wherein the tubular portion is provided with an end surface extending circumferentially around a mouth of the tubular portion, wherein the abutment surface of the base part is configured to abut the end surface of the head part when the base part and the head part are interconnected to each other in order to form said dividable dental care product.

In any of the kit of parts mentioned above, the base part may be formed of a wood-based material. In any of the kit of parts mentioned above, the base part may be formed of a polymer-based material.

The kit of parts may also comprise: a first base part having a handle portion and an interface portion, and a second base part having a handle portion and an interface portion, wherein the first base part is formed of a wood-based material and the second base part is formed of polymer-based material, wherein each one of the head parts is configured to be separably interconnected by their respective interconnection portion to the interconnection of either one of the first or second base parts allowing the respective base part to be used over a period of time and to be interconnected with each of the plurality of head parts, one at the time, during said period of time.

In a design like this it is possible to e.g., have a more exclusive first, wood-based base part at home and a second, polymer-based base part in the toilet bag ready for travelling. Alternatively, one of the base parts, such as e.g., the second, polymer-based base part may be hollow and carry electronics providing additional functionality.

The invention may also in short be said to relate to a kit of parts, and a dividable dental care product comprising a base part having a handle portion and an interconnection portion comprising a protruding portion being provided with an external threading and with a shoulder extending radially outwardly from and circumferentially around the protruding portion and presenting an abutment surface, and a head part having a dental care utility portion and an interconnection portion comprising a tubular portion with an internal threading and with an end surface extending circumferentially around a mouth of the tubular portion, wherein the abutment surface of the base part is configured to abut the end surface of the head part when the base part and head part are interconnected to each other in order to form said dividable dental care product.

The above mentioned object has also been achieved by a head part having an interconnection portion and a dental care utility portion, wherein the head part is configured to be separably interconnected with its interconnection portion to an interconnection portion of a base part, wherein the interconnection portion of the head part comprises a tubular portion extending around a central axis and being provided with an internal threading formed on an inwardly facing envelope surface of the tubular portion, wherein the tubular portion is configured to receive the interconnection portion of the base part by a threading motion about the central axis, wherein the tubular portion is provided with an end surface extending circumferentially around a mouth of the tubular portion, wherein, when the base part and the head part are interconnected to each other in order to form said dividable dental care product, the end surface of the head part is configured to abut an abutment surface of the base part facing the end surface of the head part.

The advantages associated with the general design, preferred embodiments thereof, and various variations has been discussed in detail above with reference to a dental care product and that discussion is equally relevant to the head part as such.

It may be noted that the use of first, second, third, fourth, fifth, etc. are mainly to be seen as labels facilitating reading and that it does not necessarily mean that there need to be all the intervening numbers of portions present. It may e.g., be noted that it is contemplated to have a design where there is a first portion, a second portion, a third portion and a fifth portion, with the fourth portion being omitted. However, to facilitate reading, we have consistently used the numbering first, second, third, fourth, etc., as labels, and in a sense based on an embodiment including all conceivable portions.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the [element, device, component, means, step, etc]" are to be interpreted openly as referring to at least one instance of said element, device, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

Brief description of the drawings

The invention will by way of example be described in more detail with reference to the appended schematic drawings, which shows a presently preferred embodiment of the invention.

Figure 1 discloses an assembled dental care product in the form of a two-part toothbrush.

Figure 2 discloses the dental care product of figure 1 in a disassembled state where a head part is shown separate from a base part. Figure 3 is a cross-sectional view of the head part of figure 2.

Figure 4 is a schematic view showing interconnection portions of the head part and the base part in a disassembled state.

Figure 5 is a cross-sectional view of the interconnection portion of the head part.

Figure 6 is a perspective view of the interconnection portion of the base part.

Figures 7a-c is a perspective view, a cross-sectional view, and an exploded view of a first base part which e.g., may be formed of a polymer- based material.

Figures 8a-c is a is a perspective view, a cross-sectional view, and an exploded view of a second base part which e.g., may be basically be formed of a wood-based material.

Figure 9 is a side view of an interconnection portion of the base part according to a further embodiment.

Figure 10 schematically discloses kit of parts according to various exemplary embodiments.

Detailed description of preferred embodiments

With reference to figure 1 , there is disclosed a dividable dental care product 1 comprising a base part 10 and a head part 20. The dental care product 1 is in this embodiment a toothbrush 1.

The base part 10 has a handle portion 11 and an interconnection portion 12. The head part 20 has an interconnection portion 22 and a dental care utility portion 29. The base part 10 and the head part 20 are configured to be separably interconnected by their respective interconnection portion 12, 22. In figure 1 , the head part 20 and the base part 10 are interconnected to each other to form a toothbrush 1. In figure 2, the head part 20 has been disassembled from the base part 10.

As is best shown in figures 3-5, the interconnection portion 22 of the head part 20 comprises a tubular portion 22a with an internal threading 23 formed on an inwardly facing envelope surface 22b of the tubular portion 22a. The tubular portion 22a is provided with an end surface 24a extending circumferentially around a mouth 22c of the tubular portion 22a.

As is best shown in figures 4 and 6, the interconnection portion 12 of the base part 10 comprises a protruding portion 12a extending along a longitudinal direction L along a central axis A from the handle portion 11 towards a free end 12e of the protruding portion 12a, the protruding portion 12a being provided with an external threading 13 formed in an outwardly facing envelope surface 12b of the protruding portion 12. The interconnection portion 12 of the base part 10 comprises a shoulder 14 which extends radially outwardly from and circumferentially around the protruding portion 12 and which presents an abutment surface 14a configured to face the head part 20.

As is indicated in figure 4, the protruding portion 12a is configured to be received into the tubular portion 22a by a threading motion about the central axis A. It may be noted that this movement is a relative movement and that in practice the user may train the tubular portion 22a onto the protruding portion 12 or vice versa. It is believed that the design shown in e.g., figure 1 is easiest to assemble by keeping the head part 20 still in one hand and by rotating the base part 10 using the other hand. When the base part 10 and head part 20 are interconnected to each other in order to form said dividable dental care product 1 , the abutment surface 14a of the base part 10 is configured to abut, preferably to sealingly abut, the end surface 24a of the head part 20. Both the abutment surface 14a and the end surface 24a extends in a plane in which the central axis A forms a normal.

The base part 10 is especially useful in a use scenario where the base part 10 is used over a period of time and is interconnected with different head parts 20, one at the time, during said period of time.

As shown e.g., in figures 4-6, the internal threading 23 of the tubular portion 22a and the external threading 13 of the protruding portion 12a may have a trapezoid profile. The internal threading 23 have a root thickness RT and a thread pitch P as measured long the central axis A. The thread pitch P is preferably at least two times the root thickness RT. In the preferred embodiment, the thread pitch P is about three point five times the root thickness RT, i.e. , P=3,5xRT. It is considered that the thread pitch P is preferably between two times and five times the root thickness RT. In the disclosed design, the flanks of the profile are orthogonal to the central axis A and thereby the thickness of the profile will be the same as the root thickness RT along basically the complete height of the profile. In the disclosed embodiment, the profile width or root thickness RT is about 1mm. It is considered suitable that the profile width or root thickness RT is between 0,5mm and 2mm. In the disclosed embodiment, the pitch P is about 3,5mm. It is considered suitable that the pitch P is between 2mm and 5mm.

In the preferred embodiment, the external threading 13 is correspondingly shaped. The profile of the external threading 13 has a root width RW and a thread pitch P as measured long the central axis A, wherein the thread pitch P is preferably at least two times the root width RW. In the preferred embodiment, the profile of the protruding profile of the internal threading 23 and the profile of the groove of the external threading 13 are trapezoid-shaped and the flanks of the profiles abut each other along most and even more preferably along close to the complete height, e.g., the complete height apart from any top rounding. Thus, the root thickness RT and the root width RW are almost the same.

The internal threading 23 of the tubular portion 22a and the external threading 13 of the protruding portion 12a is preferably a single entry threading. As shown e.g., in figure 6, this results in that there is a significant amount of material present between each groove forming the external threading 13. This provides a strong external threading 13. Such a design is especially suitable when it comes to allowing the base part 10 to be manufactured of a wood-based material. A single entry threading may also be beneficial during production and/or during automated assembly and/or during assembly by the user, since the base part 10 and the head part 20 have only one possible relative rotational position allowing the threading 13, 23 of the parts 10, 20 to enter into threaded engagement with each other. It may also be beneficial in the sense that it secures e.g., that any information printed, embossed, or otherwise provided on the base part 10 will be oriented in the desired orientation of the head part 20, or vice versa.

The inwardly facing envelope surface 22b of the tubular portion 22a may be tapered such that an inner diameter D22b of the inwardly facing envelope surface 22b decreases with increased distance from the mouth 22c of the tubular portion 22a. Thus, the inner diameter D22b’ at a greater distance from the mouth 22c is smaller than the diameter D22b at the mouth.

The tubular portion 22a is preferably tapered such that the inwardly facing envelope surface 22b is angled inwardly a few degrees, i.e. , such that the tubular portion 22a is almost cylindrical. The angle a by which the inwardly facing envelope surface 22b is angled relative to the central axis A is preferably between 1-5°. In the preferred embodiment, the angle a is about 2

Preferably, the top surfaces 23t of the internal threading form an imaginary circular cylinder with the imaginary envelope surface extending parallel to the central axis A. In combination with the preferred tapering of the inwardly facing envelope surface 22b, this results in that the height H 1 , H2 of the profile of the internal threading 23 decreases with increasing distance from the mouth 22c. The height H 1 , H2 of the profile of the internal threading 23 is for any given portion of the profile measured in a radial direction from the envelope surface 22b at the respective portion of the profile to the top surface 23t of the respective portion of the profile. As shown e.g., in figure 5, decreases with increasing distance from the mouth 22c such that the indicated height H1 is greater than the indicated height H2. The height H1 is the height of a portion of a portion of the threading 23 being closer to the mouth 22c compared to the portion of the threading 23 having the height H2.

The inwardly facing envelope surface 22b may comprise a non- threaded portion 22bc extending from the mouth 22c a distance L22bc along the central axis A. This distance L22bc is preferably at least equal to one times a root thickness RT of the internal threading 23. In the preferred embodiment, the distance L22bc is about two times the root thickness RT of the internal threading 23. It is considered suitable that the distance L22bc is between one and four times the root thickness RT of the internal threading 23.

It should be noted that the provision of the non-threaded portion 22bc allows, but does not necessitate, the provision of a non-treaded portion 12c in the envelope surface 12b of the protruding portion 12. Thus, even though the tubular portion 22a is provided with said non-threaded portion 22bc, the groove forming the external threading 13 may extend further towards or even all the way to the shoulder 14. Alternatively, it may be expressed as that the distance L22bc should be equal to or larger than any non-threaded portion 12c.

The protruding portion 12 may comprise a non-threaded portion 12c extending from the shoulder 14 a distance L12c along the central axis A. This distance L12c is preferably at least equal to one fifth times a root width RW of the external threading 13, i.e. , the distance L12c is at least 0,2 times the root width RW. Thus, considering that the distance L22bc should be equal to or larger than any non-threaded portion 12c, the distance L22bc could, if present as is the case in the disclosed embodiment, alternatively be defined to be as small as at least one fifth times a root thickness RT. In the disclosed embodiment, the distance L12c is about two times the root width RW of the external threading 13. It is in one embodiment considered suitable that the distance L12c is between one and four times the root width RW of the external threading 13. In an alternative embodiment, the distance L12c is between about one fifth and one times the root width RW of the external threading 13, preferably about one third times the root width RW. The distance L12c is in one preferred embodiment about 0,3mm. Thus, the distance L12c may also be said to be between about one fifth and four times the root width RW of the external threading 13.

As e.g., shown in figures 4, 6 and 9, the envelope surface 12a of the protruding portion 12 may be slightly tapered such that the diameter of the protruding portion 12 decreases with increasing distance from the shoulder 14. The protruding portion 12a is preferably tapered such that the outwardly facing envelope surface 22b is angled only a few degrees, i.e., such that the protruding portion 22a is almost cylindrical. The angle b by which the outwardly facing envelope surface 12b is angled relative to the central axis A is preferably between 1-5°. In the preferred embodiment, the angle b is about 2°. The bottoms of the grooves forming the external threading 13 preferably extends along a cylindrical envelope surface extending in parallel with the central axis A. In combination with the preferred tapering of the outwardly facing envelope surface 12b, this results in that the depth D1 , D2 of the profile or groove of the external threading 13 decreases with increasing distance from the shoulder 14. In figure 9, the depth D1 is greater than the depth D2.

As is shown in figure 9, in the vicinity of the shoulder, the outwardly facing envelope surface 22b is more sharply tapered an angle b1. This may also be combined with a small chamfer on the inside of the mouth 22c of the base part 20. This design is provided to be able to provide a distinct and sharp increase in the torque needed to lock the parts to each other and thereby also in the torque needed to release the parts from each other.

In any of the interfaces between the head part 20 and the base part 10, there may be provided a bulb 23g and recess 13g. In the preferred embodiment, the bulb 23g is formed as an inwardly extending bulb 23g on the inwardly facing envelope surface 22b of the tubular portion 22a and the recess 13g is formed as a recess in the outwardly facing envelope surface 12b of the protruding portion 12. In figure 5 it is shown that the bulb 23g extends inwardly from the inwardly facing envelope surface 22b similarly to how the threads 23 extends inwardly from the inwardly facing envelope surface 22b. In figure 6 it is shown that the recess 13g is formed in the outwardly facing envelope surface 12b. As shown in figures 5 and 6, the bulb 23g and recess 13g preferably have a small axial extension. In figure 4, it is shown that the bulb 23g and recess 23g have a small circumferential extension. In figure 4, it is also shown that the bulb 23g is intended to be in register with and be received in the recess 13g. It could be designed the other way around such that the bulb could be formed on the outwardly facing envelope surface 12b of the protruding portion 12a and the recess could be formed in the inwardly facing envelope surface 22b of the tubular portion 22a. The bulb and recess could alternatively be formed such that one of them is formed in the abutment surface 24a and the other is formed in the end surface 24a. A bulb and recess may be used to provide a distinct tactile and/or audible feedback to the user concerning that the intended interconnection has been reached.

As mentioned above, in the preferred embodiment shown in figures 1-3, the dividable dental care product 1 is a toothbrush. With reference to figures 1-3, the dental care utility portion 29 comprises a brush section 28 comprising a brush head 28a formed in the head part 20 at an end portion 20e of the head part 20 opposing the tubular portion 22a and a plurality of bristles 28b attached to a transversely oriented surface 28c of the brush head 28a.

A distance L20 along the central axis A between a distal end 28e of the brush head 28 and the mouth 22c of the tubular portion 22 may be at least 60mm, preferably between 60mm and 90mm, more preferably between 60mm and 80mm. Alternatively or as a complement thereto, a distance L20’ along the central axis A between a central position 28’ of the brush head 28 and the mouth 22c of the tubular portion 22a may be at least 45mm, preferably between 45mm and 75mm, more preferably between 45mm and 65mm. Central portion 28’ is intended to refer to a position, as seen along the central axis A, from which position 28’ the distance to a bristle being located closest to the distal end 28e is equal to a distance to a bristle being located furthest away from the distal end 28e.

As e.g., shown in figures 1-2, 4-6, an outer circumferential envelope surface 15a of the shoulder 14 of the base part 10 is preferably flush with an outer envelope surface 25a of the head part 20 at the mouth 22c of the tubular portion 22a when the base part 10 and head part 20 are interconnected to each other in order to form said dividable dental care product 1. In the preferred embodiment, the outer envelope surface 25 of the head part 20 continues smoothly from said outer envelope surface 25a at the mouth 22c. In the preferred embodiment, the outer envelope surfaces 25a, 25 are slightly inclined such that it tapers towards the care utility portion 29. In the preferred embodiment, the outer envelope surface 15 of the base part 20 continues smoothly from said outer envelope surface 15a at the shoulder 14. In the preferred embodiment, the outer envelope surface 15a of the shoulder and at least an adjoining portion of the outer envelope surface 15 of the handle 11 are slightly inclined such that it tapers towards the care utility portion 29. Preferably the angle of the envelope surfaces 25, 25a of the head part 20 are equal to the angle of said envelope surfaces 15a, 15 of the base part 10.

As is e.g., shown in figures 1-2, the base part 10 may be rotationally symmetrical about the central axis A.

In one preferred embodiment, the base part 10 and the head part 20 are formed from different materials. It may be noted that different materials may refer to completely different materials, such as polymer-based material respectively wood-based materials. However, different materials may also refer to different polymer-based materials. The different load conditions of the base part 10 and the head part 20 may e.g., be addressed using a first polymer-based material for the base part 10 and a second, different one, polymer-based material for the head part 20. It may also be noted that different polymer-based materials may refer to the use of different polymers such as polyethylene respectively polypropylene, but it may also relate to the use of different grades of the same kind of polymer, such as different grades of polyethylene. The different grades may e.g., relate to different average length of the polymer chains, different additives, etc.

The head part 20 may be formed of a polymer-based material. This choice of material is beneficial since it offers a great variety when it comes to design options.

The outer envelope surface 25 of the base part 20 is at a distance from the base part 10 more sharply tapered to form a neck 26. The neck 26 is located between the interconnection portion 22 and the care utility portion 29. As is e.g., shown in figure 5, this sharper tapering is initiated, as seen from the mouth 22c, at a position along the central axis A being located about where inwardly facing envelope surface 22c of the tubular portion 22a ends. However, as is shown in figure 5, the tubular portion 22a may be designed such that it does not end as a transversal bottom, but on the contrary it may be designed such that it continues as a conically shaped space 23h into the interior of the neck portion 26. This is especially useful if the head part 20 is produced using an injection moulding process or any similar process, since the provision of this conically shaped space 23h makes it possible to have a close to uniform material thickness which is advantageous when it comes to the injection of material and when it comes to the desire to achieve a uniform cooling of the injected material.

The base part 10 may be formed of a wood-based material. This choice of material is beneficial since it may be environmentally friendly and since it makes it easy to provide a comfortable grip feeling both when it comes to structure and shape.

The base part 10 may be formed of a polymer-based material. This choice of material is beneficial since it offers a great variety when it comes to design options. Also, a polymer-based base part 10 may be hollow, or provided with a recess, and carry electronics providing additional functionality.

It may be noted that also a base part 10 formed of a wood-based material may be hollow or provided with a recess, and carry electronics providing additional functionality.

The base part 10 may be a solid piece of material. This is especially useful in case the base part 10 is made of wood. However, a solid base part 10 may also be made of other materials, such as a polymer-based material.

The base part 10 may also be formed of different parts, such as one part forming the handle portion 11 and another part attached thereto forming the protruding interconnection portion 12. The different parts may be formed of the same material or of different materials. It is e.g., conceivable to have a handle portion 11 formed of wood and an interconnection portion 12 formed of a polymer-based material. The interconnection portion 12 could in such a case be provided with an attachment portion extending into a bore of the handle portion 11. The above-mentioned object has also been achieved by a kit of parts comprising a plurality of head parts 20 each having an interconnection portion 22 and a dental care utility portion 29. From the perspective of such a head part 20, each one of the head parts 20 is configured to one at the time be separably interconnected with its interconnection portion 22 to an interconnection portion 12 of a base part 10, wherein the interconnection portion 22 of the head part 20 comprises a tubular portion 22a extending around a central axis A and being provided with an internal threading 23 formed on an inwardly facing envelope surface 22b of the tubular portion 22a, wherein the tubular portion 22a is configured to receive the interconnection portion 12 of the base part 10 by a threading motion about the central axis A, wherein the tubular portion 22a is provided with an end surface 24a extending circumferentially around a mouth 22c of the tubular portion 22a, wherein, when the base part 10 and the head part 20 are interconnected to each other in order to form said dividable dental care product 1 , the end surface 24a of the head part 20 is configured to abut an abutment surface 14a of the base part 10 facing the end surface 24a of the head part 20.

In accordance with one embodiment all the plurality of head parts 20 in the kit of parts are of the same kind and have the same functional properties. They may e.g., all be head parts configured to form a toothbrush and they may e.g., all have the same shape and have bristles of the same design and hardness/rigidity. Thus, from a functional perspective, the head parts 20 are interchangeable. The head parts 20 may all be fully identical or may have different designs when it comes to non-functional features, such as different decors, different colourings, or the like. Such a kit of parts is e.g., useful for a user which is using or is considering to continually be using a two-part toothbrush. The user will typically purchase a new replacement sets including only a plurality of head parts 20 of the desired kind and will re-use the base part 10. Such a kit of parts is schematically identified by the box KOP1 in figure 10. The base part 10 may have been bought separately or e.g., as part of a starter-kit. Optionally, a base part 10 may be included in such a kit of parts. This latter is identified as the boxes KOP1b and KOP1 in figure 10.

In accordance with one embodiment all the plurality of head parts 20 in the kit of parts are of the same kind but have slightly different functional properties. They may e.g., all be head parts configured to form a toothbrush but the different head parts 20 may have different size and/or shape of the brush head, different size and/or shape of the bristle base section, different size and/or shape of imaginary surface spanned by the bristles top, and/or different hardness and/or rigidity of the bristles. Such a kit of parts is e.g., useful for user which is not certain which kind of brush is the best from him/her. Such a kit may, but need not, include a base part 10. Such a kit will basically be illustrated as the box KOP1, but with slight differences between the different head parts 20.

It may also be noted that the head parts 20 of the kit of parts need not all have different functional properties. It is e.g., conceivable to have a kit including one or more sub-sets of a plurality of head parts 20 being functionally interchangeable within respective sub-set. Such a kit may optionally also be provided with one or more sub-sets of a single functionally different head part 20. The set-up may e.g., be that the kit of parts includes one sub-set including a plurality of head parts 20 configured to form a toothbrush, where the bristles e.g., all have a first hardness/rigidity and are considered interchangeable and that the kit of parts also includes one other head part 20 where the bristles e.g., are different, such as being harder/more rigid, and that this one other head part 20 is intended to be used only now and then, such as if something gets stuck or when braces need specific attention. This latter may be said to be a hybrid between the two embodiments mentioned above. The first sub-set may e.g., be illustrated by the box KOP1 and the additional head part 20 may be the one also included in the box KOP2.

In one embodiment the head parts 20 in the kit of parts are of different kinds. They may all be of different kinds or they may be divided into one or more subsets each including one or more head parts. This may e.g., be embodied in a kit of parts one sub-set including a plurality of head parts 20 configured to form a toothbrush, where the bristles e.g., all have a first hardness/rigidity and are considered interchangeable, and that the kit of parts also includes one other head part 20 of a different kind, such as a completely differently designed brush used for a specific purpose, such as a brush having a pointy brush section capable of reaching areas not easily reachable using a toothbrush having an ordinarily shaped brush section. This may e.g., be illustrated by the boxes KOP1 and KOP3 in figure 10.

The kit of parts may further comprise a base part 10. This may be illustrated as any of the kit of parts discussed above in combination with the box indicated KOP1b.

In any of the kit of parts mentioned above, the base part 10 may be formed of any suitable material. In a preferred embodiment, the base part 10 is formed of a wood-based material.

The kit of parts may also comprise: a first base part 10 having a handle portion 11 and an interface portion 12, and a second base part 10 having a handle portion 11 and an interface portion 12, wherein the first base part 10 is formed of a wood-based material and the second base part 10 is formed of polymer-based material.

In such a kit of parts is each one of the head parts 20 configured to be separably interconnected by their respective interconnection portion 22 to the interconnection of either one of the first or second base parts 10 allowing the respective base part 10 to be used over a period of time and to be interconnected with each of the plurality of head parts 20, one at the time, during said period of time. Such a kit of parts may be illustrated as any of the kit of parts discussed above in combination with the box indicated KOP1b and the box indicated KOP1c. In a design like this it is possible to e.g., have a more exclusive first, wood-based base part 10 at home and a second, polymer-based base part 10 in the toilet bag ready for travelling. Alternatively, the second, polymer-based base part 10 may be hollow and carry electronics providing additional functionality.

In figures 7a-c, there is disclosed a head part 10 basically being formed as a hollowed out cylinder. This design is intended to be manufactured from a polymer-based material. This design is intended to be manufactured using an injection moulding process or any similar process where polymer-based material is heated and formed in a mould. The base part 10 is basically formed of a hollowed out cylinder forming a handle 11 and the end opposite the interconnection portion 12 is closed by an end cap 18. The interior space was during the moulding process occupied by a core of the moulding tool. The core of the moulding tool was inserted into the cavity from proximal end of the base part 10 and the opening necessarily formed to allow the core to be withdrawn is closed by the end cap 18. It may be noted that in this embodiment, both the handle portion 11 and the protruding interconnection portion 12 are hollow. The wall thickness is about the same in the hollow handle portion 11 and in the hollow protruding interconnection portion 12. This is beneficial from a manufacturing perspective since it facilitates a quick and uniform injection of the molten polymer-based material and since it facilitates a quick and uniform cooling of the injection moulded base part 10. However, the wall thickness may alternatively be different in the handle portion 11 compared to the wall thickness in the protruding interconnection portion 12.

The end cap 18 has a sleeve portion 18a intended to be inserted into the distal end of the base part 10, i.e. , the distal end of the hollow handle portion 11. The sleeve portion 18a may be provided with a ring shaped protrusion or groove 18b configured to interact with a corresponding ring shaped protrusion or groove 11 b formed on the inside surface 11 c of the hollow handle part 11. The end cap 18 may be made of a polymer-based material or of wood, or of any other suitable material.

It may be noted that the base part 10 shown in figures 7a-c, may be manufactured from other materials than a polymer-based material. It may e.g., be made of wood. The inner diameter of the hollow handle portion 11 and the inner diameter of the protruding interconnection portion 12 may be different as shown in figure 7b. However, it is also conceivable to design a hollow base part 10 such that there is the same inner diameter in both the handle portion 11 and the protruding interconnection portion 12. In such a case, the wall thickness will be larger of the handle portion 11 compared to the wall thickness of the protruding interconnection portion 12. This latter design with a uniform inner diameter through the handle portion 11 and the protruding interconnection portion 12 may e.g., be useful if the hollow base part 10 is formed of wood and the hollowed out is provided by a drilling operation using a drill or milling tool.

However, it should be noted that a drilling operation does not necessarily require a uniform inner diameter. A base part 10 having a wider inner diameter in the handle portion 11 and compared to the inner diameter in the protruding interconnection portion 12, as shown in figure 7b, may also be manufactured using a drilling operation. It could e.g., be manufactured with the aid of a drill or milling tool having a comparably narrow tip extending into the protruding interconnection portion 12 and a comparably wider body portion forming the inner diameter of the handle portion 11.

The interior hollow space may be used to receive electronic components providing additional functionality to the dividable dental care product.

In figures 8a-c, there is disclosed a head part 10 basically being formed as a hollowed out cylinder. This design may be used for different kinds of materials and is e.g., intended to be manufactured from a wood- based material. This design may be manufactured using a drilling operation.

A bore is drilled into the handle 11. The opening of the bore is closed by the end cap 18.

In this embodiment, the protruding interconnection portion 12 has not been hollowed-out. The protruding interconnection portion 12 may be a solid piece of material. It may be noted that the base part 10 shown in figures 8a-c, may be manufactured from other materials than wood. It may e.g., be made of a polymer-based material.

Also, in this embodiment, the end cap 18 has a sleeve portion 18a intended to be inserted into the distal end of the base part 10, i.e. , the distal end of the hollow handle portion 11. The sleeve portion 18a may be provided with a ring shaped protrusion or groove 18b configured to interact with a corresponding ring shaped protrusion or groove 11b formed on the inside surface 11 c of the hollow handle part 11. If the handle portion 11 is manufactured of wood it is considered suitable that the ring shaped protrusion or groove 11 b formed on the inside surface 11 c of the hollow handle part 11 is a groove formed on the inside surface 11c, the groove thereby extending into the wall of the handle portion 11.

In this context it may also be noted that although it has been discussed that the base part 10 may be of a polymer-based material or of wood, also other materials are conceivable. One material to mention in this context is a polymer-wood hybrid material, such as a polymer-based material with organic matter, such as wood fibre, cellulose fibre or other plant based matter mixed into the polymer-based material. This may be used to improve the environmental impact and/or to improve the mechanical strength of the polymer-based material.

Even though it is preferred that the dividable dental care product is designed in accordance with the disclosure in the detailed disclosure of preferred embodiments and the appended drawings, it should be noted that a specific preferred embodiment of a specific component does not necessarily have to be combined with a specific embodiment of another component.

Thus, advantages associated with a specific embodiment, including one or more features, of a specific component may be accomplished even though the other components are designed in accordance with the more general disclosure under the summary of the invention rather than being defined in accordance with the specific embodiment disclosed in the detailed description. This is e.g., true when it comes to the specific design of the head part and of the base part. Some, or all, details disclosed as a preferred embodiment of may e.g., be included in respect of the head part, whereas the base part may be designed in accordance with the more general disclosure under the summary of invention, or vice versa.

It is contemplated that there are numerous modifications of the embodiments described herein, which are still within the scope of the invention as defined by the appended claims.

It may e.g., be noted that although the external envelope surface of the protruding portion of the base part and the internal envelope surface of the tubular portion of the head part are disclosed as being tapered, one or both may be cylindrical. If an envelope surface will be cylindrical, typically the imaginary surface formed by the tips of the threading will also be cylindrical and thereby the height of the threading profile will be the same along the central axis. It is also conceivable to have combinations thereof, such as having a cylindrical portion followed by a conical portion, or vice versa, or having a first conical portion followed by a second conical portion having a different slope, or even having a number of such combinations one after the other along the central axis.

It is also conceivable that the imaginary surface formed by the tips of the threading is conical with the same angle as the external envelope surface of the protruding portion of the base part respectively the internal envelope surface of the tubular portion of the head part. In such a case the height of the threading profile will be the same along the central axis.

Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage.