Unit for a handle of a personal care tool and personal care tool

Abstract

The present disclosure provides a unit for a handle of a personal care tool, the unit including a housing and a light indication and sealing element, the housing having a proximal end closest to the head, the head being repeatedly attachable to and detachable from the handle, the light indication and sealing element including an annular structure and an elastic circular part, the annular structure being connected to the housing at the proximal end by two flexible hinges, thereby forming a circular gap between the annular structure and the housing, the circular gap being filled with a transparent and / or translucent soft elastomeric material, the transparent and / or translucent soft elastomeric material forming the elastic circular part, thereby sealing the annular structure and the housing in a substantially watertight manner.

Description

Technical Field

[0001] The present disclosure relates to a unit for a handle of a personal care tool, the unit comprising a light indication and a sealing element. The present disclosure also relates to a personal care tool comprising such a unit. Background Art

[0002] Personal care tools such as toothbrushes are well known in the art. Generally, tufts of bristles for cleaning teeth are attached to a bristle carrier or mounting surface of a brush head intended for insertion into a user's mouth. A handle is usually attached to the head and is held by the user during brushing.

[0003] Typically, the head of a toothbrush is permanently connected to the handle, for example by injection molding the bristle carrier, the handle, and the neck connecting the head and the handle in one injection molding step. After the normal service life of the toothbrush, i.e., after about three months of use, the toothbrush is discarded. To provide an environmentally friendly / sustainable toothbrush that generates less waste when discarded, it is known that toothbrushes include a replaceable (i.e., repeatedly attachable to and detachable from the handle) head or head replacement. The consumer can reuse the handle and only purchase a new head replacement instead of buying an entirely new toothbrush. Such replacements are generally less expensive than conventional toothbrushes and generate less waste.

[0004] For example, it is known that a toothbrush includes a handle to which a replaceable head is attached. The handle is provided with a cavity into which the head can be inserted. To provide a sufficiently strong connection between the head and the handle, the brush head is shaped to have a neck with a coupling anchor in a complementary engagement mechanism for engaging within a liner of the handle.

[0005] Furthermore, it is well known that many users typically apply too much force to the brush during the brushing process. However, if the cleaning elements of the toothbrush exert too much pressure on the teeth and gums, health problems can occur. Negative health consequences include gum irritation or over time, gum recession, or enamel wear. Unfortunately, the presence of these problems can exacerbate the health condition in the oral cavity. Since some users may feel that these problems stem from poor cleaning, to correct these problems, the user may apply even more force during the brushing process, which may in turn lead to more gum irritation and / or gum recession or enamel wear.

[0006] To avoid or mitigate these problems, dental professionals may recommend using a soft-bristle toothbrush. However, using a soft-bristle toothbrush does not preclude applying a high brushing force to the oral cavity. Additionally, it is very difficult for an individual to determine the optimal force required for cleaning while brushing. Although the user can apply a minimum level of force for cleaning, it is difficult to sense a level of force that is too high. Further, studies have shown that if the brushing force is increased to too high a level, the cleaning ability of the toothbrush may actually decrease. There is a need to provide a personal care tool that includes a pressure sensor. Pressure sensors are well known in the art. Such brushes that include a pressure sensor typically require a sealing element to seal the housing that houses the pressure sensor in a substantially watertight manner. However, such seals typically create a dead volume where water, toothpaste, and saliva can accumulate, allowing mold to grow over time. In particular, this is also true for internal sealing elements that need to allow some movement of certain parts of the pressure sensor. The free movement of the pivot lever of the pressure sensor must be enabled while the handle housing needs to be watertight.

[0007] An object of the present disclosure is to provide a unit for a handle (e.g., for a toothbrush) of a personal care tool that overcomes at least one of the above disadvantages. Another object of the present disclosure is to provide a personal care tool that includes such a handle. Summary of the Invention

[0008] According to one aspect, there is provided a unit for a handle of a personal care tool, the unit including a housing and a light indication and sealing element, the housing having a proximal end closest to the head, the head being removably attachable to and detachable from the handle repeatedly, the light indication and sealing element including an annular structure and an elastic circular portion, the annular structure being connected to the housing at the proximal end by two flexible hinges, thereby forming a circular gap between the annular structure and the housing, the circular gap being filled with a transparent and / or translucent soft elastomeric material, the transparent and / or translucent soft elastomeric material forming the elastic circular portion, thereby sealing the annular structure and the housing in a substantially watertight manner.

[0009] According to one aspect, there is provided a personal care tool including a head and a handle including such a unit. Brief Description of the Drawings

[0010] The present invention is described in more detail below with reference to various embodiments and the drawings, in which:

[0011] Figure 1 A cross-sectional view of an exemplary embodiment of a handle for an electrically operated personal care tool according to the present disclosure is shown, the handle including a light indication and sealing element;

[0012] Figure 2 Shown inserted into Figure 1Perspective view of the base structure in the handle, the base structure including an annular structure;

[0013] Figure 3 shows Figure 2 Perspective view of the base structure, the annular structure of the base structure being filled with a soft elastomeric material;

[0014] Figure 4 shows Figure 3 Cross-sectional view of the filled annular structure;

[0015] Figure 5 shows Figure 1 Enlarged view of the proximal end of the handle; and

[0016] Figure 6 shows Figure 5 Enlarged cross-section of the proximal end structure of the handle shown. Detailed Description

[0017] A unit for a handle adapted to be used in combination with a personal care tool, preferably an electrically operated personal care tool, includes a housing having a lumen defined by an inner surface of the housing. The housing can be made of a rigid plastic material or a metallic material such as stainless steel or aluminum. Such materials are highly durable and allow for a slender product design.

[0018] As used herein, "personal care tool" refers to any tool that can be used for personal hygiene purposes. Some suitable examples include toothbrushes, dental floss, toothpicks, razors, shavers, and trimmers. For example, the personal care tool can be battery-powered and can include a battery located within the lumen of the handle housing. A personal care tool including a head and such a handle can be an electrically operated toothbrush. The head can be repeatedly attached to and detached from the handle, for example, via a snap-fit locking mechanism, thereby providing a connection and stability strong enough between the head and the handle such that a user can perform, for example, a brushing action.

[0019] Although a high-quality handle of a personal care tool is adapted to be used for a longer period of time compared to a common tool such as a regular toothbrush that is discarded after about three months of use, a relatively inexpensive head / brush replacement can be replaced regularly, for example, after about three months. This provides a cost-effective and environmentally sustainable personal care tool, thereby providing a high-quality handle solution as well as an opportunity for cost savings since only the head must be replaced / re-purchased after a certain period of use.

[0020] The housing of the handle has a proximal end and a distal end. The proximal end is defined as the end closest to the head, and the head can be repeatedly attached to and detached from the handle. The distal end is opposite the proximal end.

[0021] To convey to the user whether too much pressure is being exerted during use of the personal care tool, the unit includes a light indication and sealing element. The light indication and sealing element not only indicates whether too much pressure is being exerted during use, but also forms an elastic sealing portion, thereby sealing the housing in a substantially watertight manner.

[0022] The light indication and sealing element includes an annular structure connected to the housing at the proximal end by two flexible hinges, thereby forming a circular gap between the annular structure and the housing. The circular gap is filled (preferably overmolded) with a transparent and / or translucent soft elastomeric material such as TPE, which forms an elastic circular portion, thereby sealing the annular structure and the housing in a substantially watertight manner.

[0023] The unit provides a handle design that does not create any dead volume where water, toothpaste, and saliva can accumulate. In the past, these problems have been observed with internal sealing elements that need to allow for some movement of the component parts.

[0024] The elastic circular portion can represent a light ring extending 360° around the handle to emit and transmit light signals. The elastic circular portion forms part of the outer surface of the handle. Since the soft elastomeric material forming the elastic circular portion is transparent / translucent, the elastic portion can be used as a sealing and light indication element to convey certain signals from the personal care tool to the user. The elastomeric material can be illuminated, for example, via a light guide by an LED. Since the transparent / translucent soft elastomeric material surrounds the entire circumference of the handle, the signal can be seen from any direction. This is particularly advantageous for products such as oral care tools, which will be held in different orientations during use. For example, the user can obtain feedback on the pressure applied during brushing, timer information, or information about the battery charge status.

[0025] The annular structure can be injection molded from a hard plastic material. For example, if the housing is made of, for example, PP, ABS, or ASA, the annular structure can be formed integrally with the housing, such as being molded integrally with the housing. Alternatively, the annular structure can be formed from a base structural component, for example, if the housing is made of stainless steel or aluminum, the base structure is inserted into the housing at the proximal end. Such base structural components can be fixedly mounted to the housing. The elastic circular portion provides watertightness of the handle. Since the seal of the elastic circular portion is static, such a seal is more reliable and durable than commonly used dynamic seals. Such seals are particularly beneficial whenever very limited space is available. In addition, such seals do not create any dead volume where water, toothpaste, and saliva can accumulate, thereby allowing for mold growth over time. Such light indication and sealing elements make the handle of the personal care tool more hygienic.

[0026] The annular structure can be integrally formed with the light guide as a single component to provide more simplicity during the assembly of the handle. The light guide can be transparent.

[0027] The light guide can transmit light from a light-emitting element (such as an LED) to a light-indicating and sealing element disposed at the proximal end of the handle. The light guide can be made of glass, polymethyl methacrylate, polycarbonate, copolyester, polypropylene, polyethylene terephthalate, or a combination thereof (e.g., polyester and polycarbonate).

[0028] The light guide can transmit electromagnetic energy (e.g., visible light) to the light-indicating element via internal reflection or external reflection. External reflection is defined as reflection where the light source is in a material of low refractive index (such as air) and is reflected from a material of higher refractive index (such as aluminum or silver). A mirror acts in external reflection.

[0029] Internal reflection is defined as reflection where the light source is in a material of higher refractive index (such as polycarbonate) and is reflected from a material of lower refractive index (such as air or vacuum or water). Fiber optic technology operates based on the principle of internal reflection.

[0030] The refractive index is defined as the optical property of any material that measures the tendency of light to refract or bend as it passes through the material. Even materials that do not conduct light (such as aluminum) have a refractive index. Generally, external reflection is most effective when the angle of incidence of light is close to perpendicular (i.e., the light is close to perpendicular to the surface), and external reflection decreases as the angle of incidence increases (approaching the surface at a steep angle). In contrast, internal reflection is most effective at high angles of incidence and cannot reflect at shallow angles such as perpendicular to the surface. To achieve internal reflection, the angle of incidence should be greater than the critical angle. The critical angle is the angle at which light no longer reflects between a pair of materials.

[0031] If external reflection is utilized, a foil or some other highly reflective material can be used. A highly reflective material, such as a foil, can be disposed on the inner surface of the inner cavity. If internal reflection is utilized, the light guide / light path can be made of a material having a high refractive index (e.g., greater than 1.0). For example, the materials selected for the light guide can include refractive indices greater than about 1.4, greater than about 1.5, greater than about 1.6, and / or less than about 1.7, less than about 1.6, or less than about 1.5. The materials selected for the light guide can have a refractive index between about 1.4 and about 1.6 to provide excellent light transmission characteristics.

[0032] The housing of the unit may include an inner cavity that houses a rotationally mounted connector-pressure sensor unit that may be integrally formed as one piece. In other words, the rotationally mounted connector-pressure sensor unit may include a pressure sensor and a connector for repeatedly attaching and detaching the head to and from the handle. The connector and the pressure sensor may be formed as an inseparable piece. The connector may extend through an opening at the proximal end of the housing, allowing the head to be repeatedly attached to and detached from the handle. The pressure sensor may include a pivot lever. The pivot lever may be housed within the inner cavity of the housing and may extend with its distal end towards the distal end of the housing, which is opposite the proximal end. The pivot lever of the rotationally mounted connector-pressure sensor unit may be connected, for example, by gluing to an annular structure to allow a degree of movement / rotation of the rotationally mounted connector-pressure sensor unit. Alternatively, if the annular structure is formed as an infrastructure component, the pivot lever may be attached to the infrastructure component via a pivot axis.

[0033] In other words, while the pivot lever is connected to the annular structure or the infrastructure, the brush head may be attached to the connector geometry outside the housing. Using the rotationally mounted connector-pressure sensor unit according to the present disclosure allows for a simple handle construction and simplified manufacturing. A flexure hinge may be positioned near the pivot axis of the pivot lever and may provide the annular structure with the same degree of freedom as the pivot lever.

[0034] The pivot lever and / or the connector may be integrally molded from a rigid plastic material to provide a relatively inexpensive and robust component / unit.

[0035] In other words, during the assembly of the handle, the pivot lever may be connected to the annular structure in a watertight manner. By using a soft elastomeric material to allow movement of the pivot lever, an elastic portion in the handle is defined. A watertight connection may be achieved, for example, by gluing between the annular structure and the pivot lever. The elastomeric material allows free movement of the pivot lever while providing a watertight seal between the housing and the pivot lever.

[0036] The pivot lever may activate a pressure sensor switch, for example, arranged on a printed circuit board assembly (PCBA). If a predetermined level of force, such as 5 N or greater, is applied to the head of the personal care tool, the pivot lever pivots within the inner cavity of the handle; the pressure sensor switch contacts the PCBA to trigger a light signal visible to the user. The PCBA mechanically supports and electrically connects electrical or electronic components using conductive traces. If the pressure sensor switch contacts the PCBA, electrical communication may be provided between an energy source and a light-emitting element (such as an LED) via the PCBA.

[0037] The personal care tool of the present disclosure can be an electrically operated personal care tool, such as an electrically operated toothbrush. Such toothbrushes exhibit the following advantages: they assist the user during brushing and can promote improved cleaning of teeth and gums, especially in areas of the oral cavity that are difficult to reach.

[0038] Brushes according to the art that perform a vibrating action typically have a motor located in the handle housing near the head to allow most of the vibration to be transmitted to the head. The motor vibrates the entire handle while also vibrating the brush head attached to the handle. However, the amplitude of vibration at the brush head depends on the way the user holds the handle: with a softer grip, the handle can vibrate more extensively, so the user feels more vibration on the teeth. However, if the user holds the handle tightly, the vibration will be significantly suppressed and the brush head will vibrate less during use. Thus, the performance of a vibrating toothbrush, including the in-mouth sensation during use, highly depends on the user's behavior. Additionally, if the user holds the brush tightly during brushing and the vibration is suppressed too much, the user may apply even more pressure, resulting in gum and enamel damage.

[0039] According to the present disclosure, a motor with an eccentric mass for operating the personal care tool can be housed within the inner cavity of the housing. The motor can be attached to the distal end of a pivot lever. In other words, while the brush head can be attached to the connector geometry of a rotationally mounted connector-pressure sensor unit outside the housing, the vibrating motor is located at the other end of the pivot lever inside the housing to allow maximum generation of vibrations that can be transmitted to the brush head via the pivot lever without being significantly absorbed by the housing.

[0040] The inner cavity can also house an energy source (such as a battery) and / or other devices for operating the personal care tool.

[0041] Since the pivot lever is attached to the proximal end of the housing such that the pivot lever can move independently of the housing and the motor including the eccentric mass is attached at the distal end of the pivot lever, the vibrations generated by the motor can be directly guided to the brush head. Even if the housing is held tightly, the pivot lever can freely swing and transmit the vibrations to the brush head. Thus, the in-mouth sensation and cleaning performance during brushing are enhanced. Compared to a conventional brush embodiment with a vibrating function (where the motor vibrates the entire handle and head), the handle according to the present disclosure allows vibrations independent of the way the user holds the handle; since the pivot lever can move independently of the housing, the amplitude of vibration is less suppressed.

[0042] The current structure of the handle for an electrically operated personal care tool allows constant vibration regardless of how the user holds the handle and the actual consumer use. The handle is sturdy, and the soft elastomeric material allows the pivot lever to vibrate substantially independently of the housing.

[0043] In addition, the handle structure according to the present disclosure can be provided by traditional manufacturing techniques such as hard / soft overmolding.

[0044] The outer wall of the housing can include another opening (e.g., a cutout) provided along the longitudinal extension of the handle to accommodate a switch assembly for activating an energy source (e.g., switching an electrically operated personal care tool to an on / off state). The switch assembly can be attached to the inner surface of the wall of the housing, thereby sealing the opening provided in the wall.

[0045] The switch assembly for operating the tool can include a hard switch part and a soft switch part; the hard switch part includes a frame with a recess. The frame of the hard switch part can be attached to the inner surface of the metal wall and surround the opening, while the recess of the frame provides / forms an undercut that opens towards the opening to accommodate a part of the soft switch part. The soft switch part can be positioned in the undercut provided by the recess and can be arranged in such a way that it at least partially covers the opening.

[0046] Typical housings for electrical hand-held devices in the art are usually made of plastic materials. While the housing itself is molded from a hard plastic material such as PP or ABS, such devices usually include a switch area molded from a soft elastomeric material such as TPE to form a membrane that allows actuation of a switch located inside the housing. By overmolding a soft part onto a hard plastic housing, a waterproof housing assembly can be achieved only if the correct material combination and geometry are selected; sufficient bonding characteristics between the hard part and the soft part are crucial.

[0047] However, if an elongated integral product design with a housing made of metal having a small wall size is to be provided, a waterproof assembly cannot be ensured by simply overmolding a soft part onto the metal housing because the bonding area is not large enough (due to the low wall thickness and the reduced degree of freedom in designing such a metal tube housing and the freely formed plastic part).

[0048] In order to be able to provide a waterproof switch assembly (i.e., a durable and waterproof seal / adhesion between the switch assembly and the metal material) in combination with a metal tube housing having a small wall size (e.g., between 0.4 mm and about 1.2 mm) without the need to use a separate sealing element, the present disclosure proposes a switch assembly including a hard switch part and a soft switch part as described above. The hard switch part may include a frame with a recess which in turn forms an undercut when attached to the inner surface of the housing. The frame surrounds an opening, and the undercut provided between the recess and the inner wall surface opens towards the opening. The soft switch part is positioned in the undercut and is thus supported by the opposite walls of the recess and the inner wall surface respectively. The hard switch part can be fixed in the housing by gluing and / or by other means, including but not limited to material-to-material adhesion, mechanical interlocking or friction connection. The soft switch part can be provided by overmolding. The hard switch part can be further supported by an infrastructure inserted into the lumen of the housing. The infrastructure may include carrier holding parts for an electrically operated personal care tool, such as a motor, electronics and an energy source, such as a battery.

[0049] The formation of an undercut by the recess of the frame of the hard switch part allows for a solid anchoring of the soft switch part. As the frame provides a reaction force and holds the soft switch part in place, neither a force applied to the switch part from outside the housing nor a force applied from inside the housing creates significant peel stress on the bonding area. The switch assembly according to the present disclosure can be seamlessly integrated into an opening in the housing and can seal the opening in a substantially waterproof manner. Such a design prevents water, toothpaste and saliva from entering the housing; a hygienic electrically operated personal care tool can be provided.

[0050] Compared with the present disclosure, simply overmolding the soft switch part onto a metal tube housing does not provide a durable waterproof handle housing because the bonding force between the soft switch part and the metal tube housing is not strong enough; the bonding area between the two parts (the soft switch part and the metal tube housing) is not large enough and does not provide a reaction force to hold the soft switch part in place. If a force is applied to the switch part to activate the electrically operated tool, peel stress appears in the bonding area, which significantly weakens the bonding connection. The weakened bonding connection may result in fine cracks or fissures, allowing water to enter the lumen of the handle metal tube housing.

[0051] The hard switch part of the present disclosure can be made of a hard plastic material, such as made of acrylonitrile-butadiene-styrene (ABS) and / or acrylonitrile-styrene-acrylate (ASA), while the soft switch part can be made of a soft elastomeric material, such as made of thermoplastic elastomer (TPE).

[0052] The opening for receiving the switch assembly in the receiving housing can be, for example, a cutout provided in the metal wall by laser cutting. The metal wall surrounding the opening can define the angle α between its outer surface and the adjacent surface / side wall as 90° or less. If the angle α is less than 90°, the bonding area between the metal wall and the soft switch component is slightly increased, which results in even better bonding characteristics.

[0053] The frame of the hard switch component can include at least two protrusions for accurately positioning the hard switch component onto the inner surface of the metal wall / centering the hard switch component precisely during assembly. Such protrusions can help define the position of the hard switch component relative to the metal tube housing, thus facilitating manufacturing.

[0054] The handle can include magnetic / ferromagnetic material, which can allow for hygienic storage of the oral care tool by magnetically attaching the handle to, for example, a magnetic holder provided at the wall. If the personal care tool is a toothbrush, residual water, toothpaste slurry, and saliva can drain from the brush. The tool can dry relatively quickly. Thus, bacterial growth can be significantly reduced, making the oral care tool more hygienic. Compared to a conventional toothbrush stored in a toothbrush cup, where the drained fluid is collected and accumulates at the bottom of the cup, the period of time the brush according to the present disclosure is exposed to humid conditions is significantly shorter.

[0055] The magnetic holder can have the form of a flat disk that can be attached to the wall. Such a flat disk can represent an easily cleanable surface. Additionally, the user only needs to bring the oral care tool close to the magnetic holder, and then the oral care tool automatically attaches. No precise positioning or threaded connection like that of a conventional toothbrush holder is required. If the magnetic properties are provided only in the handle and not in the head, the head portion will not accidentally attach to the magnetic holder, thus reducing the risk of soiling the magnetic holder.

[0056] The handle or a part of the handle can be electroplated to enhance the appearance and provide a comfortable feel. Thermoplastic elastomers are very suitable for electroplating because they allow for the formation of both hard and soft composite components to be selectively electroplated in one operation.

[0057] For example, the handle may include a thumb rest made of a thermoplastic elastomer material and / or a polypropylene material. Such a thumb rest may provide improved gripping characteristics to the handle, such as anti-slip characteristics to improve the maneuverability of the personal care tool under wet conditions, such as when the user is brushing their teeth. The thumb rest may be made of a thermoplastic elastomer material having a Shore A hardness of about 30 to about 60, or about 40, so as to prevent the oral care tool from being too slippery when used under wet conditions. At least a portion of the thumb rest may have a concave shape with an angle α of about 20° to about 25°, or about 24°, relative to the area of the remainder of the thumb rest. The thumb rest or the gripping area may be attached to the front surface of the handle in an area near the proximal end (i.e., closest to the head). The thumb rest may include, for example, a plurality of ribs extending substantially perpendicular to, parallel to, or diagonally to the longitudinal axis of the oral care tool. Such ribs may allow the user / consumer to use the oral care tool with even more control. The user / consumer may better grip and maneuver the handle of the oral care tool during brushing. Such a handle may provide further improved control and greater comfort during brushing, especially under wet conditions.

[0058] The thermoplastic elastomer material may form a thumb rest on the front surface of the oral care tool and / or a palm grip on the rear surface opposite the front surface for gripping by the fingers and thumb of the user / consumer. Such a handle configuration may further resist slipping during use.

[0059] If the personal care tool is a toothbrush, the tooth cleaning elements, such as a tuft of filaments forming one or more clusters, can be attached to the toothbrush head by a thermal tufting process. A method of manufacturing a head having filament clusters embedded in the head may include the following steps: In a first step, a cluster is formed by providing a desired amount of filaments. In a second step, the cluster is placed in a mold cavity such that the ends of the filaments that are to be attached to the head extend into the cavity. The opposite ends of the filaments that do not extend into the cavity may be end-rounded or non-end-rounded. For example, in the case where the filaments are tapered filaments with sharp tips, the filaments may be non-end-rounded. In a third step, the head is formed around the ends of the filaments extending into the mold cavity by an injection molding process, thereby anchoring the cluster in the head. Alternatively, the cluster can be anchored by forming a first portion (so-called "sealing plate") of the head around the ends of the filaments extending into the mold cavity using an injection molding process before forming the rest of the oral care tool. Before starting the injection molding process, the ends of the cluster extending into the mold cavity may optionally be melted or fusion-bonded to join the filaments together in a melt or a molten ball such that the melt or molten ball is located within the cavity. The cluster can be held in the mold cavity by a molding rod having a blind hole corresponding to the desired position of the cluster on the finished head of the oral care tool. In other words, the clusters attached to the head by the thermal tufting process do not overlap on the middle portion along their length and are not installed in the head using an anchor / nail. The clusters can be installed on the head using a tufting process without anchors.

[0060] Alternatively, the head for the oral care tool can be provided with a bristle carrier having at least one cluster hole (e.g., a blind-ended hole). The cluster including multiple filaments can be fixed / anchored in the cluster hole by a binding process / anchor tufting method. This means that the filaments of the cluster are bent / folded in a substantially U-shaped manner around an anchor, such as a cable anchor or an anchor plate, which is made of, for example, metal. The filaments together with the anchor are pushed into the cluster hole such that the anchor penetrates into the opposite sidewalls of the cluster hole, thereby anchoring / fixing / securing the filaments to the bristle carrier. The anchor can be fixed in the opposite sidewalls by positive frictional engagement. In the case where the cluster hole is a blind-ended hole, the anchor holds the filaments against the bottom of the hole. In other words, the anchor can be located substantially vertically above the U-shaped bend. Since the filaments of the cluster are bent around the anchor in a substantially U-shaped configuration, the first branch and the second branch of each filament extend from the bristle carrier in the filament direction. The type of filament that can be used / suitable for the binding process is also referred to as a "two-sided filament". The head for the oral care tool manufactured by the binding process can be provided in a relatively low-cost and time-effective manner.

[0061] The following is a non-limiting discussion of exemplary embodiments of oral care tools and their components according to the present disclosure, with reference to the accompanying drawings.

[0062] Figure 1 Shown is a personal care tool 10, which in this particular embodiment is an electrically operated oral care tool, namely a toothbrush 10. The toothbrush 10 includes a handle 12 and a head (not shown), the head being removably and repeatedly connectable to and detachable from the handle 12 via a connector 16. The connector 16 may include a spring-loaded ball element having a ball and a spring, the spring applying a radial force to the ball in a direction towards the outer surface of the connector. The ball may be inserted into a groove provided in a hollow portion of the head to securely fix the head to the handle.

[0063] The handle 12 includes a housing 20 defining an inner cavity 18. The housing 20 has a proximal end 22 closest to the head and a distal end 24. The distal end 24 is opposite the proximal end 22.

[0064] The connector 16 is integrally formed with a pressure sensor 26 including a pivot lever 28 to form a rotatably mounted connector-pressure sensor unit 100. The pivot lever 28 is received within the inner cavity 18 of the housing 20. When the connector 18 extends through an opening 30 provided at the proximal end 22 of the housing 20, a distal end 32 of the pivot lever 28 extends in the direction of the distal end 24 of the housing 20. The pivot lever 20 and the connector 16 may be integrally molded from a rigid plastic material.

[0065] A motor 34 including an eccentric weight for operating the personal care tool 10 is attached to the distal end 32 of the pivot lever 28. A battery for operating the personal care tool 10 is also received within the inner cavity 18 of the housing 20.

[0066] The pivot lever 28 can activate a pressure sensor switch 40, for example arranged on a printed circuit board assembly (PCBA) 42. If a predetermined level of force, such as 5 N or greater, is applied to the head of the personal care tool 10, the pivot lever 28 pivots and contacts the PCBA 42 to trigger a light signal visible to the user. Via the PCBA 42, electrical communication is provided between a battery 38, provided as an example of an energy source, and a light-emitting element such as an LED.

[0067] An optical waveguide 44 can transmit light from the light-emitting element to a light indicator and sealing element 46 provided at the proximal end 22 of the handle 12 (see Figure 3 ). The light indicator and sealing element 46 can be a light ring 46 extending 360° around the handle 12 and forming a part of the outer surface of the handle 12. The light indicator and sealing element 46 is part of a unit 200 including the housing 20.

[0068] The light indicator and seal element 46 includes an annular structure 50 and a transparent and / or translucent soft elastomeric material forming an elastic circular portion 56. The annular structure 50 is connected to the housing 20 at the proximal end 22 by two flexible hinges 52, thereby forming a circular gap 54 between the annular structure 50 and the housing 20. This circular gap 54 is filled with a transparent and / or translucent soft elastomeric material 56, thereby forming the elastic circular portion 56, thus sealing the annular structure 50 and the housing 20 in a substantially watertight manner.

[0069] Figure 2 A perspective view of the infrastructure 48 inserted into the housing (see Figure 1 ) through an opening 30 provided at the proximal end 22 is shown. The infrastructure 48 includes an optical waveguide 44 and an annular structure 50, and the optical waveguide 44 and the annular structure 50 are integrally molded from a hard plastic material. The pivot lever 32 is connected to the annular structure 50, for example, via gluing.

[0070] As Figure 3 shown, the gap 54 between the annular structure 50 and the housing 20 is filled with a transparent or translucent soft elastomeric material 56 (e.g., overmolded) to provide a light ring for transmitting the optical signal received from the optical waveguide 44, and this soft elastomeric material is preferably TPE. The soft elastomeric material 56 seals the housing 20 in a substantially watertight manner while still providing sufficient freedom of movement to allow the pivot lever 28, which is integrally molded with the connector 16, to bend.

[0071] Figure 4 A cross-sectional view of the annular structure 50 filled with a transparent material 56 (e.g., overmolded) is shown.

[0072] Figure 5 And Figure 6 An enlarged view of the proximal end 22 of the handle 12 is shown, where the connector-pressure sensor unit 100 is inserted into the housing 20.

[0073] During the assembly of the handle 12, the pivot lever 28 can be connected to the annular structure 50 in a watertight manner. By using the soft elastomeric material 56 to allow the movement of the pivot lever 28, this soft elastomeric material defines the elastic portion 56 in the handle 12. A watertight connection 58 can be achieved, for example, by gluing between the annular structure 50 and the pivot lever 28. The elastomeric material 56 allows the free movement of the pivot lever 28 while providing a watertight seal between the housing 20 and the pivot lever 28.

[0074] As Figure 1 shown, the handle further includes a switch assembly 60 located in the housing 20 for activating the energy source / battery 38, such that the electric toothbrush 10 operates. The electric toothbrush 10 can be switched between the on / off states by actuating the switch assembly 60.

[0075] The switch assembly 60 for activating the energy source / battery 38 includes a hard switch member 62 and a soft switch member 64. Both the hard switch member 62 and the soft switch member 64 are located within an opening 66 provided in the housing 20. The hard switch member 62 and the soft switch member 64 are arranged such that the switch assembly 60 seals the opening 66 in a substantially waterproof manner.

[0076] While the hard switch member 62 can be molded from a hard plastic material, such as made of acrylonitrile-butadiene-styrene (ABS) and / or acrylonitrile-styrene-acrylate (ASA), the soft switch member 64 can be made of a soft elastomeric material, such as made of thermoplastic elastomer (TPE). TPE adheres well to metallic materials as well as ABS and ASA.

[0077] The hard switch member 62 includes a frame with a recess, which is attached to the inner surface of the housing 20 so as to surround / enclose the opening 66. The recess forms an undercut, in which the soft switch member 64 is positioned and firmly fixed. The hard switch member 62 can be connected to the inner surface of the housing 20 by gluing. Alternatively, fixation of the hard switch member 62 on the inner surface can be provided by material-to-material bonding, mechanical interlocking, or frictional connection.

[0078] The frame of the hard switch member 62 can include protrusions, which help to position the hard switch member 62 onto the inner surface of the housing 20; for this purpose, the inner surface can include corresponding recesses for receiving the protrusions.

[0079] The hard switch member 62 can further include a lever arm, which includes a button element at the distal end of the lever arm. The lever arm and the button element can extend into the opening 66.

[0080] The material forming the soft switch member 64 can be overmolded on the lever arm and partially over the button element, so as to keep a portion of the button element exposed to provide an indication of the position where the user should place his finger to activate the switch assembly 60. For this purpose, the color of the material of the hard switch member 62 and the color of the material of the soft switch member 64 can be different to provide a clear and easily visible indication. The material of the soft switch member 64 covers any remaining open area of the opening 66 and is fixed in an undercut provided between the recess and the inner surface of the housing 20. By overmolding the soft switch member 64, a substantially waterproof and durable seal can be provided, which can prevent water, toothpaste, and / or saliva from entering the inner cavity 18 of the housing 20.

[0081] In the context of the present disclosure, the term "substantially" means an arrangement of an element or feature structure which, although theoretically expected to exhibit exact conformity or behavior, may in fact render something somewhat less precise. Similarly, the term represents such a degree that a quantitative value, a measured value or other relevant representation may differ from the reference without causing a change in the basic function of the subject matter under discussion.

[0082] The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, each such dimension is intended to mean the recited value and a functionally equivalent range surrounding that value, unless otherwise indicated. For example, a dimension disclosed as "40 mm" is intended to mean "about 40 mm".

Claims

1. A unit (200) for a handle (12) of a personal care tool (10), the unit (200) comprising a housing (20) and a light indication and sealing element (46), the housing (20) having a proximal end (22) closest to the head, the head being repeatedly attachable to and detachable from the handle (12), the light indication and sealing element (46) comprising an annular structure (50) and an elastic circular part (56), the annular structure (50) being connected to the housing (20) at the proximal end (22) by two flexible hinges (52) so as to form a circular gap (54) between the annular structure (50) and the housing (20), the circular gap (54) being filled with a transparent and / or translucent soft elastomeric material (56), the transparent and / or translucent soft elastomeric material forming the elastic circular part (56) to seal the annular structure (50) and the housing (20) in a substantially watertight manner.

2. The unit (200) according to claim 1, wherein the circular gap (54) is filled with the transparent and / or translucent soft elastomeric material (56) by overmolding.

3. The unit (200) according to claim 1 or 2, wherein the light indication and sealing element (46) is made of a flexible material.

4. The unit (200) according to claim 1 or 2, wherein the transparent and / or translucent soft elastomeric material (56) is a thermoplastic elastomer (TPE).

5. The unit (200) according to claim 1 or 2, wherein the annular structure (50) is integrally formed with the housing (20).

6. The unit (200) according to claim 1 or 2, wherein the annular structure (50) is formed as an infrastructure component that is inserted into the housing (20) at the proximal end (22) of the housing (20), and the annular structure (50) is connected to the housing (20) at the proximal end (22) of the housing (20) by the flexible hinges (52).

7. The unit (200) according to claim 1, wherein the housing (20) includes an inner cavity (18), the housing (20) having a distal end (24), the distal end (24) of the housing (20) being opposite to the proximal end (22) of the housing (20), the inner cavity (18) accommodating a rotatably mounted connector-pressure sensor unit (100), the connector-pressure sensor unit (100) comprising a connector (16) and a pivot lever (28), the connector extending through an opening (30) at the proximal end (22) of the housing (20), the pivot lever extending towards the distal end (24) of the housing (20), and the pivot lever (28) being attached to the annular structure (50).

8. The unit (200) according to claim 7, wherein the connector-pressure sensor unit (100) is integrally manufactured as one piece.

9. The unit (200) according to claim 7 or 8, wherein the pivot lever (28) is attached to the annular structure (50) by gluing.

10. The unit (200) according to claim 1, wherein the housing (20) includes an inner cavity (18), the housing (20) has a distal end (24), the distal end (24) of the housing (20) is opposite to the proximal end (22) of the housing (20), the inner cavity (18) houses a rotatably mounted connector-pressure sensor unit (100), the connector-pressure sensor unit (100) includes a connector (16) and a pivot lever (28), the connector extends through an opening (30) at the proximal end (22) of the housing (20), the pivot lever extends towards the distal end (24) of the housing (20), and the pivot lever (28) is attached to the base structural member via a pivot axis (36).

11. The unit (200) according to claim 10, wherein the connector-pressure sensor unit (100) is integrally formed as one piece.

12. The unit (200) according to claim 8 or 11, wherein the rotatably mounted connector-pressure sensor unit (100) is integrally molded from a hard plastic material.

13. The unit (200) according to claim 7 or 10, wherein the housing (20) houses a motor (34) including an eccentric weight.

14. The unit (200) according to claim 13, wherein, At the end of the pivot lever (28) of the rotatably mounted connector-pressure sensor unit (100), the distal end of the pivot lever (28) is closest to the distal end (24) of the housing (20), and the motor (34) is attached to the pivot lever (28) at the distal end of the pivot lever (28).

15. The unit (200) according to claim 1 or 2, wherein the housing (20) includes an energy source for operating the personal care tool (10).

16. The unit (200) according to claim 15, wherein the energy source is a battery.

17. A personal care tool (10) comprising a head and a unit (200) according to any one of claims 1 to 16.

18. The personal care tool (10) according to claim 17, wherein the personal care tool (10) is electrically operated.

19. The personal care tool (10) according to claim 18, wherein the personal care tool (10) is an electrically operated toothbrush.

20. The personal care tool (10) according to any one of claims 17 to 19, wherein the head can be repeatedly attached to and detached from the handle (12), and the handle (12) includes the unit (200).

Images