Detailed Description
One aspect of the present disclosure relates to a connection, in particular a detachable connection, between an attachment portion and a handle portion of an oral hygiene device, in particular an electrically powered oral hygiene device, wherein at least one connection (a connection established between movably mounted components that are driven during operation and serve to transfer motion from a motor in the handle portion to a functional element in the attachment portion) between the attachment portion and the handle portion is realized as a magnetic coupling. Mechanical couplings typically have an inherent tolerance-based clearance or gap between the coupling partners so that the coupling partners can move relative to each other when a corresponding connection is established between the components being driven during operation. Such mechanical connections then tend to produce objectionable noise during operation. The magnetic coupling can be designed with inherently small clearances, so that the magnetic coupling is likely to generate little noise.
In some embodiments, an accessory portion according to the present invention includes a first magnetic coupling element having at least a permanent magnet or a magnetizable element. The first magnetic coupling is arranged for establishing a magnetic connection with a second magnetic coupling element provided in the handle portion in the attached state.
In some embodiments, the accessory portion can further include an accessory housing, a functional element mounted at the accessory housing for driven movement, and a motion transmitter. The motion transmitter may be coupled to the functional element on one end to transmit motion to the functional element and may be equipped with a first magnetic coupling element on the other end. The motion transmitter may in particular extend in a cavity formed within the accessory housing. In some embodiments, the functional element may be a working element such as a brush head for cleaning teeth. In some embodiments, the accessory housing may have a first coupling structure intended for establishing a further connection with a second coupling structure provided at the handle portion.
On the one hand, magnetizable elements (e.g. magnetizable steel or iron elements) can be realized relatively inexpensively, and the attachment part for disposal after a period of use can then be realized relatively inexpensively. This is especially interesting in case the cost of the permanent magnet would be of the same order of magnitude as the cost of the whole accessory part. On the other hand, the permanent magnets in the attachment portion together with the permanent magnets in the handle portion may provide a higher coupling strength than a combination of permanent magnets and magnetizable elements in the same constructional volume.
In some embodiments, the first magnetic coupling element comprises a protective cover that prevents corrosion or abrasion of the first magnetic coupling element. In such embodiments, the protective cover may be erosion resistant in the sense that it remains undamaged during the typical life of the accessory portion. When the oral hygiene device is used in a wet environment and is typically used with abrasive and/or corrosive chemicals such as mouthwashes or toothpaste, a thin coating such as, for example, a 10 micron thick gold coating can be abraded off in a relatively short period of time. Covers made of metal, ceramic, glass or abrasion resistant plastic or resin layers of about 20 μm or more, optionally about 30 μm or more, also optionally 40 μm or more, and even still optionally about 50 μm or more, may be used. In some embodiments, the protective cover may have a thickness as follows: 60 μm or more, 70 μm or more, 80 μm or more, 90 μm or more, 100 μm or more, 150 μm or more, or 200 μm or more, and/or any thickness within or including the values provided above or any range within or including the values provided above. In some embodiments, the protective cover is realized as a substantially cup-shaped element that may be mounted by gluing, press-fitting, crimping, shrink-fitting, stamping, welding, snapping, or any combination thereof. In some embodiments, the protective cover is realized as a disc or dish that can be glued to said magnetic coupling element. In some embodiments, protective covers manufactured in a deep drawing, press drawing, or thermoforming process are used.
In general, the protective cover may be designed to be wearable for a brief period of time corresponding to a typical lifetime of the accessory portion. A typical use period may be about three months with a two to four minute on-period per day, so the operational use period may be about 540 minutes to about 1.080 minutes. However, protective covers may be designed to resist erosion for longer or shorter periods of time. Specifically, in some embodiments, covers that resist abrasion for much longer than 1.080 minutes, such as 2.000 minutes, 4.000 minutes, 10.000 minutes, or even longer, may be used.
In some embodiments, the first magnetic coupling element is at least partially received in a recess or cavity provided in the motion transmitter. In some embodiments, the motion transmitter may include a retainer element in which the first magnetic coupling element is at least partially received. In some embodiments, the motion transmitter may comprise a rod element, in particular a rod element made of a metal, such as stainless steel. Such metal rods are likely to provide stability not provided by motion transmitters made entirely of plastic materials. The lever element may in some embodiments be pivotally mounted at the functional element, in particular at a mounting position which is offset from an axis about which the functional element is to be driven during operation. Alternatively or additionally, the rod element may be pivotally mounted at a holder element having a groove at least partially accommodating the first magnetic coupling element, e.g. a holder element as described above. The pivotal mounting of the lever element makes it possible to support a relative movement between the lever element and the functional element or the holder element, respectively.
In some embodiments, the accessory part, the cover, the first magnetic coupling element and/or the motion transmitter have a centering structure intended for supporting at least the centering of the first magnetic coupling element with the second magnetic coupling element during the attachment process.
In some embodiments, the first magnetic coupling element may have at least one indentation or groove filled with a plastic material, in particular with an injection-molded plastic material. For example, the holder element as described above may be manufactured in a plastic injection molding step, wherein the first magnetic coupling element is an insert element. Then, the manufacturing step of, for example, snapping the first magnetic coupling element into the retainer element may be discarded, and further, then if the two parts of the first magnetic coupling element and the retainer element are later installed, the injection molding step may result in a smaller gap or clearance between the two parts.
In one embodiment, the attachment part is arranged such that the motion transmitter is mounted without any return force element, which will affect the behavior of a resonant drive with a further spring provided in the handle part. Because springs typically have tolerances, a spring in the attachment portion intended for coupling with a drive shaft of a resonant drive in the handle portion can help the spring-mass system determine the resonant frequency of the resonant drive. In addition, the springs in the attachment portion may also generate additional noise in operation due to the tolerances required to mount the springs.
In some embodiments, the handle portion for connecting, optionally detachably, with an accessory portion as described above comprises a second magnetic coupling element arranged at the drive shaft, said second magnetic coupling element being arranged for establishing a magnetic connection with the first magnetic coupling element provided at the accessory portion; and a second coupling structure for establishing a connection, in particular a mechanical connection (e.g. a force-fit or a form-fit connection), with the first coupling structure provided at the accessory part, in particular at the accessory housing. The second magnetic coupling element may comprise at least a permanent magnet or a magnetisable element.
In at least some embodiments, a handle section according to the present invention comprises a linear drive (i.e., a resonant drive providing a linear reciprocating motion or a dc motor with gears for converting a rotary motion into an oscillating linear motion) for driving the drive shaft in a longitudinal direction (substantially parallel to or coincident with the longitudinal axis of the drive shaft) for linear oscillation. In some embodiments, the linear drive may provide a linear oscillatory motion amplitude by the drive shaft in a range between about ± 0.1mm to about ± 2.0mm, specifically in a range between about ± 0.5mm to about ± 1.5mm, optionally in a range between about ± 0.75mm to about ± 1.25mm, further optionally in a range between about ± 0.9mm to about ± 1.1mm, and even further optionally a linear oscillatory motion amplitude of about ± 1.0 mm. In some embodiments, the accessory part comprises a gear assembly that converts the linear motion provided by the drive shaft and transmitted to the motion transmitter into an oscillatory rotation with a maximum angular deflection in the range between ± 5 ° to ± 40 °, in particular in the range between about ± 10 ° to ± 30 °, optionally in the range between about ± 15 ° to about ± 25 °, and optionally also about ± 20 ° (wherein the angular deflection is measured in the unloaded state of the functional element).
The longitudinal axis referred to in all embodiments extends generally along the longitudinal or lengthwise dimension of the drive shaft or is parallel to or coincident with the longitudinal axis of the drive shaft. The drive shaft refers to the drive shaft of the motor or an extension thereof.
In one embodiment, the second magnetic coupling element may have a protective cover that protects the second magnetic coupling element from corrosion. The protective cover may be wear resistant in the sense that it remains undamaged during the typical life of the handle portion. When the oral hygiene device is used in a wet environment and is typically used with abrasive and/or corrosive chemicals such as mouthwashes or toothpaste, a thin coating such as, for example, a 10 micron thick tin coating can be abraded off in a relatively short period of time. Protecting covers made of metal, ceramic, glass or abrasion resistant plastic or resin layers of about 20 μm or more thick, optionally about 30 μm or more thick, also optionally 40 μm or more thick, and even still optionally about 50 μm or more thick may be more suitable. In some embodiments, the protective cover may have a thickness as follows: 60 μm or more, 70 μm or more, 80 μm or more, 90 μm or more, 100 μm or more, 150 μm or more, or 200 μm or more, and/or any thickness within or including the values provided above or any range within or including the values provided above. In some embodiments, the protective cover is realized as a substantially cup-shaped element that may be mounted by gluing, press-fitting, crimping, shrink-fitting, stamping, welding, snapping, or any combination thereof. In a particular embodiment, the protective cover is realized as a disc or dish that can be glued to said magnetic coupling element. The protective cover for the second magnetic coupling may be constructed similar to that described above with reference to the first magnetic coupling.
In one embodiment, the second magnetic coupling element is at least partially received in a recess provided in the drive shaft. In one embodiment, the handle portion, the protective cover, the second magnetic coupling element and/or the drive shaft may have a centering mechanism intended for supporting at least the centering of the first and second magnetic coupling elements during the attachment process.
In some embodiments, the oral hygiene device may comprise at least an accessory portion according to the present invention and it may further comprise a handle portion having a second magnetic coupling element and a second coupling structure for establishing a connection with a first coupling structure provided at the accessory portion. In some embodiments, the oral hygiene device may comprise a handle section as described in the preceding paragraphs that is at least an attachment section as described herein and further in line with a handle section as described above. In some embodiments, the handle portion comprises a drive having a drive shaft arranged to provide a linear oscillatory motion during operation, and the contact face of the magnetic coupling element is arranged substantially perpendicular to the direction of the linear motion.
In some embodiments, as will be explained in more detail further below, the magnetic coupling between the first and second magnetic coupling elements is designed to at least partially disengage if a pull-off force exerted on the magnetic connection exceeds a threshold force. Such at least partial disengagement of the magnetic coupling partner is then likely to interrupt the motion transmission and generate noise, which may draw the attention of the user, thus informing the user that the load is too high.
For example, where the oral hygiene implement is an electric toothbrush and the attachment has a replaceable brush head as a functional element mounted for oscillating a rotating bristle carrier, the magnetic coupling between the motor in the handle portion of the oral hygiene device and the motion transducer in the attachment portion should be in a coupled state for typical pull-off forces generated during operation (i.e., brushing teeth in the exemplary case). During brushing, typical pull-off forces generated between the first and second magnetic coupling elements may be generated, in particular, due to friction between the treatment elements (e.g., bristles) mounted on the carrier and hard or soft tissue in the oral cavity (e.g., teeth or gums). The friction increases with the pressure with which the functional element (e.g., the brush head) is applied to the hard or soft tissue (e.g., the teeth). Typical applied pressure values may be in the range between about 1.5 newtons (N) and about 3.5N (pressures below this range are generally not used or do not produce correct treatment results, and pressure values above this range may cause discomfort or even damage), particularly in the range between about 2N and 3N. For the above oscillating rotating brush head, it has been found that the pull-off force acting at the magnetic coupling may then be in the range of above 5N, and in particular above 6N, and further in particular between about 6.5N to about 8.0N. The higher pull-off force may then result from the user applying too high a pressure or from the bristles becoming caught between two teeth. In both cases, it may be advisable to arrange the magnetic coupling to disengage when a pull-out force above the highest and allowable pull-out force occurs. First, it may support an indication to the user that too high a pressure is applied, as detachment may be apparent to the user. Second, when the magnetic coupling is to be subjected to high pull-off forces, such a pull-off may reduce the pain that can occur if a bristle that is caught between the teeth is pulled out. In both cases, detachment is possible so as to protect the soft and hard tissues from abrasion and other types of damage. Thus, the threshold force may be set to 5N, 5.5N, 6N, 6.5N, 7N, 7.5N, 8N, 8.5N, 9N, 9.5N or 10N, wherein in particular the threshold force may be set to the following values: at least 6.5N, optionally at least 7N, further optionally at least 7.5N and still even further optionally at least 8N. As will be seen further below, the threshold force may in particular be set by designing the magnetic coupling accordingly, for example by selecting the dimensions of the first and second magnetic coupling elements, selecting the material from which the first and second coupling elements are made or selecting the gap between the first and second magnetic coupling elements.
Although it is proposed here to design the magnetic coupling in such a way that it is decoupled in the event of application of a pull-out force above a threshold force, the above example is experimentally obtained for a bristle carrier for driven oscillatory rotation mounted at the housing of an attachment. Although it is not excluded that other functional elements may produce the same threshold force, it may be found that another threshold force value is equally preferred according to experimental studies for other functional elements or for another intended oral hygiene application, such as tongue cleaning or gum massaging.
In some embodiments, the accessory part has a first magnetic coupling element comprising a magnetizable element, which may in particular be made of stainless steel, such that a further protective cover may be disposed of, the magnetizable element fitting into a cylinder having a diameter of at least about 4.5mm and a length of at least about 4.5 mm. Optionally, the diameter may be at least about 5.0mm, and also optionally at least about 5.5 mm. Optionally, the length may be at least about 5.5mm, and also optionally at least about 6.5 mm.
In some embodiments, the handle portion has a second magnetic coupling element comprising a permanent magnet, in particular made of NdFeB, fitted into a cylinder of at least about 4.5mm in diameter and at least about 4.5mm in length. Optionally, the diameter may be at least about 5.0mm, and also optionally at least about 5.5 mm. Optionally, the length may be at least about 5.0mm, and also optionally at least about 5.5 mm.
In some embodiments, the motion transmitter is non-detachably connected with the accessory part, in particular with a functional element mounted for driven motion.
Hereinafter, specific implementations of a plurality of exemplary embodiments will be given. It should be noted that all of the features described in this disclosure, whether they are disclosed in the more general examples described above or in the exemplary embodiments described below, even though they may be described in the context of a particular embodiment, are of course disclosed as individual features which can be combined with all other disclosed features, as long as this will not contradict the spirit and scope of the disclosure. In particular, all features disclosed for either of the first or second magnetic coupling elements are also applicable to the other.
Fig. 1 is a perspective view of an exemplary embodiment of an oral hygiene device 1, here embodied as an electric toothbrush. The oral hygiene device 1 comprises a handle portion 200 and an attachment portion 100. Here, the attachment section 100 is implemented as a removable brush section. The attachment part 100 has a functional element 130, here realized as a brush head, wherein said functional element 130 is movably mounted at the attachment housing 150 such that the functional element 130 can be driven into an oscillating rotation (as indicated by the double arrow 21) about a rotational axis R, which can be perpendicular to the longitudinal axis L of the attachment part 100. Instead of being realized as an electric toothbrush, the oral hygiene device may be realized as an (electric) tongue scraper, an (electric) flossing device, an (electric) interdental cleaner, or the like. The attachment portion may then be realized as a tongue scraper portion, a flossing portion, an interdental cleaning portion, etc., respectively. The functional elements may accordingly be realized as tongue scraper heads, flossing heads, interdental cleaning heads, etc.
Fig. 2 is a lateral cross-sectional cut through the attachment portion 100 taken along the longitudinal axis of the attachment portion 100. The accessory portion 100 includes an accessory housing 150 and a functional element 130 that is movably attached to the accessory housing 150.
The functional elements 130 may include a carrier element 131 on which a plurality of cleaning elements 133 may be mounted for cleaning and massaging portions of the oral cavity, such as the teeth and gums. The carrier element 131 may be mounted to the attachment housing 150 via a mounting shaft 132 for driven oscillating rotation about a rotational axis R that is substantially perpendicular to the longitudinal axis (reference L in fig. 1) of the attachment portion 100.
The accessory portion 100 can also include a motion transmitter 110 disposed within a cavity 159 formed within the accessory housing 150. The motion transmitter 110 can be functionally connected to a functional element 130, as explained in more detail with reference to fig. 3. Generally and applicable to all embodiments, "functionally connected" shall mean a connection that is not intended to be disconnected and that shall allow the kind of motion transmitted by the motion transmitter to be transmitted to the functional element. The motion transmitter 110 is arranged for transmitting a linear oscillatory motion to the functional element 130, which may be substantially parallel to the longitudinal axis of the attachment part 100 (as indicated by the double arrow a). Such a linear oscillating movement may be provided by the drive shaft of the handle section when the attachment section 100 is in the attached state, as will be explained in more detail in connection with fig. 5.
The motion transmitter 110 may comprise a recess 112 realized as a blind hole provided at a first end 110A adjacent to an opening of the cavity 159, wherein the opening is at an end of the accessory part 100 (i.e. the first end 110A of the motion transmitter 110 is distal to the functional element 130). The first magnetic coupling element 120 is disposed in the groove 112. In general and applicable to all embodiments, as described above for all described structures, the first magnetic coupling element 120 may be implemented as a permanent magnet or a magnetizable element such as a piece of magnetizable iron or steel. Generally, austenitic steels are non-magnetizable, while martensitic rigid or ferritic steels are generally magnetizable. The first magnetic coupling element 120 has a coupling side 121 oriented towards the opening provided at the distal end of the attachment portion 100. In general and applicable to all embodiments, the coupling side 121 is retractable from an opening at an end of the accessory housing intended for coupling with the handle portion, such that a magnetic connection is established at a longitudinal position within the accessory housing, in particular wherein the longitudinal position is retracted from said end of the accessory housing by the following value: in a range between about 0.5cm to about 5.0cm, such as 1.0cm, 1.5cm, 2.0cm, 2.5cm, 3.0cm, 3.5cm, 4.0cm, 4.5cm, or any other value within the range, and the length of the accessory housing can be in a range between about 3.0cm to about 10.0 cm.
The first magnetic coupling element 120 may be secured to the motion transmitter 110 in any suitable manner. For example, the first magnetic coupling element 120 may be glued to the motion transmitter 110, it may be snapped into a recess, it may be secured by injection molding at least a portion of the motion transmitter thereon, or it may be secured by other methods, as will be further explained below.
In some exemplary embodiments, the first magnetic coupling element is realized as a magnetizable iron or steel element. If the first magnetic coupling element is realized in a corrosive material, such as iron or NdFeB material (from which relatively strong permanent magnets can be made), at least the coupling side of the first magnetic coupling element may have a protective cover to protect the first magnetic coupling element from corrosion.
The protective cover may be implemented as a coating, a top cover, a top cap, or a cup, as will be described in more detail further below. In general and applicable to all embodiments, any protective cover applied to the first magnetic coupling element or the second magnetic coupling element in the attached state may create a distance between the first magnetic coupling element and the second magnetic coupling element and thus result in a reduction of the effective coupling force between the first magnetic coupling element and the second magnetic coupling element, such that the following protective cover thicknesses may be selected: about or less than 0.5mm, optionally about or less than 0.4mm, further optionally about or less than 0.3mm, even further optionally about or less than 0.2mm, and still even further optionally about or less than 0.1mm per shield. In other embodiments, the protective cover may include a thickness as previously described. In the illustrated embodiment, the first magnetic coupling element 120 is glued into the groove. It may have an anti-corrosion coating applied to the coupling side 121 or a protective cover that may be glued on the coupling side 121. In the illustrated embodiment, when the other side of first magnetic coupling element 120 is protected by the surrounding material of motion transmitter 110, it will be sufficient to secure a disk-shaped cover to coupling side 121 of first magnetic coupling element 120.
In general and applicable to all embodiments, first magnetic coupling element 120 may be realized as a cylindrical element having a cylindrical axis direction substantially parallel to the longitudinal axis of attachment portion 100, wherein the diameter of the cylinder may be selected to be about or greater than 2mm, optionally about or greater than 3mm, further optionally about or greater than 4mm, even further optionally about or greater than 5mm, and still even further optionally about or greater than 6mm, and/or any number or range including or within the provided values.
The cylindrical element may have any suitable height. In exemplary embodiments, the height may be selected to be about or greater than 2mm, optionally about or greater than 3mm, yet optionally about or greater than 4mm, even yet optionally about or greater than 5mm, and still even yet optionally about or greater than 6mm, and/or any number or range including or within the provided values. In some exemplary embodiments, the height of the first magnetic coupling element may be selected to be as large as the diameter. In other embodiments, the second magnetic coupling element may be designed to have any suitable shape. In this case, the smallest possible cylinder into which such a first magnetic coupling element can fit may have a diameter and a height as described above.
In some exemplary embodiments, the first magnetic coupling 120 is implemented as a permanent magnet. In the case where the attachment portion 100 is a disposable attachment portion intended for detachable attachment to the handle portion 200 of an oral hygiene device, material cost can be seen as an important aspect. Implementing the first and second magnetic coupling elements 120, 120 as permanent magnets may result in a relatively high coupling force, whereas implementing the first magnetic coupling element 120 as a magnetizable element, such as an iron or steel element, may reduce the material cost of the attachment portion 100.
The accessory portion 100 as shown in fig. 2 may also include an insert element 151 that is snapped into the accessory housing 150, thereby forming a portion of the accessory housing 150. The insert element 151 may be equipped with a first coupling structure 152 intended for establishing, in the attached state, a further coupling (i.e. a coupling different from the magnetic coupling to be established by the first magnetic coupling element 120) with the handle portion of the oral hygiene device. In the exemplary embodiment shown, the first coupling structure 152 is realized by a mechanical coupling means, such as a snap or spring element, for clamping a protrusion provided at the handle portion. In other exemplary embodiments, the first coupling structure 152 may be realized by an additional magnetic coupling element. The longitudinal positions in which the magnetic connection is established and in which the further connection (e.g. the mechanical connection) is established may in particular be separated by a distance in the range between about 0.5cm and about 3.0 cm.
Fig. 3 is a transverse longitudinal cross-sectional cut through the exemplary attachment portion shown in fig. 2, with the viewing direction facing the cleaning elements. As can be seen from fig. 3, the motion transmitter 110 is coupled to the functional element by a coupling pin 111 provided at the second end 110B of the motion transmitter 110. The coupling pin 111 establishes a coupling with a coupling portion 134 provided at the carrier element 131 at a position eccentric with respect to the rotational axis defined by the mounting shaft 132. When the motion transmitter 110 is driven in a linear oscillatory motion as indicated by the double arrow a, then the carrier element 131 will be driven in an oscillatory rotation about the axis of rotation. As will also be explained further below, in some embodiments, motion transmitter 110 is not associated with any return force element, such as a biasing spring, that biases the motion transmitter into a defined rest position whenever the motion transmitter is not being driven.
Fig. 4 shows a longitudinal cut through illustrative handle portion 200. In the exemplary embodiment shown, handle portion 200 includes a drive shaft 210 that serves as a movable motor component of a resonant linear drive 260 disposed within handle housing 250. During operation, the linear drive 260 provides a linear oscillating motion of the drive shaft 210 as indicated by the double arrow B. In the exemplary embodiment shown, the drive shaft 210 may be extended by an expander element 219, which thus forms part of the drive shaft 210. The expander element 219 may provide an increase in diameter relative to the diameter of the drive shaft 210. A recess 211 may be provided in the extender element 219 for receiving the second magnetic coupling element 220. Instead of being accommodated in the extender element 219, the second magnetic coupling element 220 may of course be fixed directly at the drive shaft 210, or the drive shaft may be made of permanent magnetic material at least at its end portion, wherein the end would then form the second magnetic coupling element 220. The second magnetic coupling element 220 has a coupling side 221 intended for contacting, when attached, a corresponding coupling side 121 (shown in fig. 2) of the first magnetic coupling element 120 (shown in fig. 2) of the accessory part. The coupling side of the first magnetic coupling element and the coupling side of the second magnetic coupling element may be flat or may at least partially abut each other.
In general and applicable to all embodiments, the second magnetic coupling element 220 may be realized as a cylindrical element having a cylindrical axis direction substantially parallel to the longitudinal axis of the drive shaft, wherein the diameter of the cylinder may be selected to be about or greater than 2mm, optionally about or greater than 3mm, further optionally about or greater than 4mm, even further optionally about or greater than 5mm, and still even further optionally about or greater than 6mm, and/or any number or range including or within the provided values. The cylindrical member may have any suitable height. For example, the height may be selected to be about or greater than 2mm, optionally about or greater than 3mm, yet optionally about or greater than 4mm, even yet optionally about or greater than 5mm, and still yet even yet optionally about or greater than 6 mm. In some exemplary embodiments, the height may be selected to be as large as the diameter. In other embodiments, the second magnetic coupling element may be designed to have any suitable shape. In this case, the smallest possible cylinder into which such a second magnetic coupling element fits may have a diameter and a height as described above.
Generally, the handle portion comprises a handle housing at which a second coupling structure intended for establishing a connection with a first coupling structure provided at the attachment portion is realized. In the exemplary embodiment shown, the handle portion 200 has a handle housing 250 comprising a handle housing top portion 250A intended for coupling with an accessory portion and a handle housing lower portion 250B to be held by a user's hand. Here, the handle housing top portion 250A includes a top member 251 at which a second coupling structure 252 may be implemented. The second coupling structure 252 may form an additional connection with the first coupling structure 152 (shown in fig. 2) of the accessory portion.
In some embodiments, the second coupling structure 252 and the first coupling structure may establish a coupling that may be different from the connection established by the first and second magnetic couplings, or the coupling may be similar. For example, the coupling established by the first and second coupling structures may include a mechanical lock, a magnetic lock, the like, or combinations thereof. In some embodiments having a housing top portion 250A and a housing lower portion 250B, the housing top portion 250A may be arranged for driven motion, e.g., the housing top portion 250A may perform oscillatory rotation about a longitudinal axis, longitudinal linear vibration, and/or linear reciprocating motion in a direction substantially parallel to the longitudinal axis of the drive shaft during operation. In such embodiments, an accessory housing coupled to housing top portion 250A performs a first motion, such as rotation about a longitudinal axis, longitudinal linear vibration, and/or linear reciprocating motion, during operation, while the motion transmitter may drive a functional element in a second motion. The first and second movements are further described with reference to fig. 5. In some embodiments, the housing top portion 250A is not driven and remains stationary relative to the housing lower portion 250B.
Fig. 5 shows a longitudinal cross-sectional cut view of the housing top portion of the attachment section 100 and the handle section 200 in an attached state. It is shown that the first and second magnetic coupling elements 120, 220 have established a magnetic connection coupling the drive shaft 210 of the handle section 200 with the motion transmitter 110 of the attachment section 100, such that during operation, a linear reciprocating motion of the drive shaft 210 as indicated by the double arrow B will be transmitted to the functional element 130 via the motion transmitter 110. In some embodiments, such coupling does not require the transmission of rotational motion since the motion transmitted is a linear reciprocating motion, such that flat coupling sides of the first and second magnetic coupling elements are suitable.
Further, the first coupling structure 152 and the second coupling structure 252 have established a second connection between the accessory housing 150 and the handle housing 250 such that the accessory portion 100 is fixed relative to the handle housing 250. For those embodiments in which the housing top portion is driven to oscillate rotationally about a longitudinal axis, longitudinally linearly vibrate, and/or linearly reciprocate in a direction generally parallel to the longitudinal axis of the handle 200, the motion of the housing top portion is transferred to the accessory housing via the connection provided between the first coupling structure 152 and the second coupling structure 252.
As already mentioned, the motion transmitter 110 may be mounted without any return force elements. If a mechanical connection is to be established between the motion transmitter and the drive shaft, it is known to use a return force element for the motion transmitter provided in the attachment part, since then the coupling force needs to be overcome substantially first during the attachment process. Without a return force element, the motion transmitter would likely be pushed away during attachment and the mechanical coupling may not be easily established. With the described magnetic coupling, when the attachment part is attached to the shank part, the first and second magnetic coupling elements will attract each other and the motion transmitter will then move towards the drive shaft in order to establish the magnetic coupling without first having to overcome any resistance. Particularly with a handle portion comprising a resonant drive in which the resonant frequency depends on a spring-mass system comprising a return force element (such as a spring acting on a motion transmitter), tolerances in the spring will result in variations in the resonant frequency of the resonant drive for different accessories. In addition, the elimination of the return force element supports cost-effective manufacturing.
In general and applicable to all embodiments, the first and second magnetic coupling elements 120, 220 may each be implemented as a permanent magnet or a permanent magnet arrangement or as a magnetizable element such as an iron or steel element or a structure of such elements. Any kind of permanent magnet material may be used, for example the energetic material SmCo or NdFeB, but also as sintered or plastic bonded elements, or any hard ferrite such as sintered strontium ferrite may be used. Plastic bonded permanent magnet elements tend to have relatively low magnetic flux densities when compared to, for example, sintered permanent magnets. Sintered NdFeB magnets have relatively high flux densities, but are also relatively expensive and prone to corrosion. Hard ferrite magnets are relatively inexpensive and do not corrode as easily as ceramic materials, but have a limited magnetic flux density. If one of the first or second magnetic coupling elements is realized as a magnetizable element, the other of the first or second magnetic coupling elements is to be realized as a permanent magnet or a permanent magnet structure. Permanent magnets are widely used, for example, commercially available from IBS Magnet (Berlin, Germany).
In some embodiments, at least one of the first or second magnetic coupling elements is made of or at least partly consists of NdFeB material, in particular sintered NdFeB material. In some of these embodiments, the second magnetic coupling element provided in the handle portion is made of or consists at least partially of a sintered NdFeB material. The latter allows to realize the first magnetic coupling element as a relatively cheap magnetizable element such as an iron or steel element or by an arrangement of such elements.
Perishable permanent magnets such as, for example, sintered NdFeB magnets, are generally available from commercial suppliers with thin corrosion-resistant coatings such as tin or nickel coatings. Unfortunately, toothpaste can abrade these standard coatings fairly quickly during operation. It is then necessary to equip these permanent magnets with a low-abrasion and corrosion-resistant cover to withstand the conditions during operation of the oral hygiene device. For the lid, various materials may be selected such as low-abrasion plastic materials (e.g., for making deep-drawn plastic cups), ceramics, metal foils, glass, and the like.
Some permanent magnet materials, such as NdFeB, have a low operating temperature, such as 60 degrees celsius, where the operating temperature also depends on the specific dimensions of the permanent magnet. For such permanent magnets, corrosion protection may not be applied by an injection molding process, during which temperatures of 200 degrees celsius and higher may exist, and the permanent magnet may lose its magnetic properties. The protective cover may be applied by casting (e.g., resin), gluing (e.g., metal, ceramic or glass plate), snapping, welding, etc., as already mentioned.
The magnetic coupling established by the first and second coupling elements should, as mentioned above, withstand typical pull-out forces exerted on the functional element, so that the magnetic coupling is not separated when such forces are applied. In an exemplary embodiment, a typical pull-off force acting on the functional element may be at most 10 newtons, i.e. the magnetic coupling should withstand a pull-off force of at most the following threshold values: about 10 newtons, optionally up to about 9 newtons, further optionally up to about 8 newtons, even further optionally up to about 7 newtons, yet further optionally up to about 6 newtons, yet further optionally up to about 5 newtons, and even more preferably up to about 4 newtons or any value within or including the values provided.
Fig. 6A to 6D show four different exemplary configurations S1 to S4 of the first and second magnetic coupling elements. Fig. 7 shows simulation results of the effective forces present between the coupling partners in the coupled state, wherein the results are shown for various values of the gap between the first and second magnetic coupling elements, which gap reflects the protective cover on one or both magnetic coupling elements.
Fig. 6A shows a first configuration S1 in which first magnetic coupling element 410A is a cylindrical NdFeB permanent magnet and second magnetic coupling element 420A is a stainless steel cylinder. The diameter d1 of NdFeB permanent magnet 410A was set to 5mm in the simulation, and the height h1 was set to 5 mm. The stainless steel element was set to a diameter d2 of 5mm and its height h2 to 4.5 mm. The arrow 419A indicates the magnetization direction of the permanent magnet, which is set here as the cylinder axis along the longitudinal direction. The total height of the magnetic coupling configuration is thus 9.5mm plus the gap thickness.
Fig. 6B illustrates a second configuration S2, wherein the only difference from the first configuration S1 illustrated in fig. 1 is the magnetization direction 419B of the first magnetic coupling element 410B, which is selected to be perpendicular to the longitudinal cylindrical axis.
Fig. 6C shows a third configuration S3 of the first and second magnetic coupling elements 410C and 420C. The second magnetic coupling element 420C is again assumed to be a stainless steel element, but here has a height of 3.5 mm. The first magnetic coupling element 410C consists of an NdFeB permanent magnet having a height of 5mm and a diameter of 3.5 mm. The NdFeB permanent magnets were glued into a cup-shaped iron vessel having an outer diameter of 5mm and an inner diameter of 4 mm. The iron container is composed of a hollow iron cylinder 4104C and a disc-shaped back iron 4103C. The disc-shaped back iron 4103C has a diameter of 5mm and a height of 1.5 mm. The total height of the magnetic coupling configuration is thus also 9.5mm plus the gap thickness. The magnetization direction of NdFeB permanent magnet 4101C is indicated by arrow 419C and is assumed to be along the longitudinal cylindrical axis.
Fig. 6D shows a fourth configuration S4 in which the second magnetic coupling element 420D is a stainless steel cylinder having a height of 3.5mm and a diameter of 5mm as in the third configuration S3. First magnetic coupling element 410D is comprised of first and second semi-cylindrical NdFeB permanent magnets 4101D and 4102D that are oppositely magnetized in the longitudinal direction, as indicated by magnetization arrows 4191D and 4192D, respectively. The cylinder consisting of two semi-cylindrical NdFeB permanent magnets has a height of 5mm and a diameter of 5 mm. On the back side, the two semi-cylindrical NdFeB permanent magnets are terminated by a back iron 4103D having a disc shape with a height of 1.5mm and a diameter of 5 mm. The total height is again 9.5mm plus the gap thickness.
In the simulations performed, it was assumed that the remanence of the NdFeB permanent magnet was 1370 mT. The properties of the stainless steel 1.4021 were calibrated by measurement.
Fig. 7 shows simulation results for the four configurations S1, S2, S3, and S4 described above in connection with fig. 6A through 6D. The abscissa indicates the gap between the flat coupling sides of the first and second magnetic coupling elements in millimeters. The gap material is assumed to be air. The ordinate indicates the force in newtons between the first and second magnetic coupling elements in the coupled state. It can be seen that configuration S4 generally yields the highest threshold force value at which the magnetic coupling can withstand a pull-off force, e.g., at a 0.1mm gap, configuration S4 yields a threshold force value of about 7.3 newtons at which the first and second magnetic coupling elements will disengage. Other configurations produce coupling forces of about 3.4 to 4.9 newtons at a gap of 0.1 mm.
Fig. 8 is a schematic cross-sectional cut through the top of the drive shaft 510 with the second magnetic coupling element 520. In the illustrated embodiment, the second magnetic coupling element 520 is glued into a protective cover 525 having a generally cup-shaped form. During the attachment step, the protective cover 525 has, on its top side (where the first magnetic coupling element 620, indicated by the dashed line, will be close to the second magnetic coupling element 520), a centering structure 526 implemented by a flange, so that a groove 527 is formed into which the first magnetic coupling element 620 fits. Flange 526 may taper towards the proximate first magnetic coupling element 620 to support a centering function. Although the magnetic coupling itself already has some self-centering function, the centering structure supports the centering step and may avoid misalignment between the first and second magnetic coupling elements. As previously described, the first and second magnetic coupling elements may be interchanged with respect to the described configuration, for example, fig. 8 may show an exemplary embodiment of the first magnetic coupling element.
Here, the protective cover is realized by a cup that completely accommodates the second magnetic coupling element 520 and extends at least partially over the drive shaft 510. In such embodiments, when the glue layer 524 secures the drive shaft 510 and the second magnetic coupling element 520, there is no need to additionally secure the second magnetic coupling element 520 to the drive shaft 510. The thickness d3 of the glue layer 524 and the protective cover 525 should be chosen as low as possible to avoid reducing the possible coupling forces (see fig. 7). In fact, the coupling side 521 does not need to be glued to the cover, since the side glue layer is sufficient to establish a firm connection. The thickness d3 can be selected to be about or less than 0.2mm, optionally about or less than 0.15mm, further optionally about or less than 0.1mm, and even further optionally about or less than 0.05mm, or any number and/or any range within or including the values provided. The material of the protective cover may be a plastic material, ceramic, glass or (in particular non-magnetizable) metal. To reduce the thickness of the glue layer 524 and the protective cover, embodiments are contemplated in which the glue layer is only present on the sides of the drive shaft 510 and the second magnetic coupling element 520, and is not present between the coupling side 521 of the second magnetic coupling element 520 and the bottom surface 531 of the protective cover.
A protective cover made of magnetizable material will in the example shown in fig. 8 result in a magnetic short-circuit between the magnetic north and south poles of the permanent magnet and the available force between the magnetic coupling elements will be reduced.
Fig. 9 is a schematic view showing another embodiment of the top of the drive shaft 510A having a groove 511A that receives the second magnetic coupling element 520A. The curved wall portion 512A secures the second magnetic coupling element in the groove 511A. Prior to introducing the second magnetic coupling element 520A into the groove 511A, the wall portion 512A may be straight to allow the second magnetic coupling element 520A to be inserted into the groove 511A. Then, the wall portion 512A may be bent, for example, using press forming, such that the second magnetic coupling element 520A is secured in the groove. The protective cover 525A may cover the remaining opening such that the second magnetic coupling element 520A is protected from corrosion. The protective cover 525A may be a resin as previously described or any suitable material. If the top of the drive shaft 510A is made of a (non-magnetizable) metal or other low-abrasion material that can be formed in a stamping process, the protective cover 525A is effectively protected from abrasion and therefore does not necessarily need to have high abrasion resistance at this point.
Fig. 10 is a schematic diagram illustrating another embodiment of the top of the drive shaft 510B and the first magnetic coupling element 620B. The drive shaft 510B has a recess 511B accommodating a second magnetic coupling element 520B, said second magnetic coupling element 520B extending above the drive shaft 510B such that a stepped structure 526B is obtained. The protective cover 525B, which may be implemented as a deep drawn plastic cup, may have a glue layer 524B glued over the extended top of the second magnetic coupling element 520B and the top of the drive shaft 510B. The first magnetic coupling element 620B may include a recess 626B adapted to the stepped structure 526B such that the stepped structure 526B and the recess 626B cooperate to support centering of the first magnetic coupling element 620B and the second magnetic coupling element 520B during attachment. Similar to the embodiment shown in fig. 8, to reduce the gap width between the first and second magnetic coupling elements, the glue layer 524B may not be present between the coupling side 521B and the bottom surface 531B of the protective cover 525B. For those embodiments in which the first magnetic coupling includes a protective cap, a similar structure may be provided.
Fig. 11 is a schematic view of the lower portion of motion transmitter 610C in which recess 611C is provided to receive first magnetic coupling element 620C. The recess 611C may be equipped with a snap nose 612C (here embodied with a 90 ° undercut on its back side) so that the first magnetic coupling element 620C with the respective recess is (non-detachably) fixed on the motion transmitter 610C by a mechanical part, here embodied as a snap part. At their front side (the side closer to the handle than the back side), the snap noses 612C may be tapered so that the first magnetic coupling element 620C may be pushed into place (snapped) during manufacturing. The motion transmitter may be implemented as a plastic piece while the first magnetic coupling element 620B may be implemented as a non-corrosive steel piece.
In other embodiments, a protective cover realized as a cup similar to the embodiment shown may be fixed at the drive shaft by crimping, shrink fitting, welding or snapping, for example.
12A, 12B, and 12C illustrate various views of another exemplary embodiment of an attachment portion according to the present invention. Like parts have the same reference numerals in the three views. This is done with reference to all three figures 12A, 12B and 12C. Not all reference numerals have been repeated among the figures.
The attachment part 700 has an attachment housing 750, a functional element 730 embodied as a brush head mounted at said attachment housing 750 for driven oscillating rotation about a rotational axis R1, wherein the rotational axis R1 is substantially perpendicular to the longitudinal extension direction of the attachment part 700. Accessory portion 700 also includes a motion transmitter 710 that extends within a cavity 759 formed within accessory housing 750.
The functional element 730 (here: the brush head) has carrier elements 731 on which cleaning elements, such as bristle tufts, can be mounted. Carrier element 731 can comprise a coupling element 731A, which can specifically be an integral part of carrier element 731. Carrier element 731 can be mounted at accessory housing 750 by means of fixing element 738 such that it cannot be easily detached from accessory housing 750.
Motion transmitter 710 may include a retainer element 712 and a rod element 716. The retainer element 712 can at least partially receive the first magnetic coupling element 720 in the groove 711 at the first end 710A of the motion transmitter 710. The rod member 716 may be made of metal, such as stainless steel, in particular, and optionally may be made of metal wire. The metal rod element may provide a higher stiffness and elasticity than a corresponding motion transmitter part made of plastic material. Due to the higher toughness of plastic materials compared to metals, the motion transmitter can be made entirely as a single, unitary component from plastic materials. The rod element 716 may have a first coupling part 716A pivotally mounted at the holder element 712 and a second coupling part 716B pivotally mounted at a coupling portion 739 provided at the coupling element 731A of the carrier element 731. At least one of the first coupling part 716A or the second coupling part 716B of the rod element 716 may be a curved rod portion that may extend into a hole or a blind hole in the holder element 712 or the coupling element 731A, respectively. As seen in particular in fig. 12C, first magnetic coupling element 720 may have at least indentations or grooves 729 filled with injection molded plastic 714, i.e., first magnetic coupling element 720 may have been directly over-molded with retainer element 712. This direct overmolding step in manufacturing results in a minimum gap or clearance between the first magnetic coupling element 720 and the retainer element 712. Generally and applicable to all embodiments, the first magnetic coupling element may be directly over-molded with at least a portion of the motion transmitter, and the recess present on the first magnetic coupling element may be filled with an injection-molded plastic material, so that the first magnetic coupling element is firmly fixed at this injection-molded part of the motion transmitter.
The holder element 712 has protrusions 713 extending in the longitudinal extension direction at the edge of the contact surface 721 of the first magnetic coupling element 720, which protrusions may be tapered radially outwards, such that these protrusions form a centering structure that at least supports centering of the magnetic connection between the first magnetic coupling element 720 and the second magnetic coupling element of the handle portion during attachment of the attachment part 700. When the first and second magnetic coupling elements have been disengaged due to a pull-off force that is too high and the high pull-off force has disappeared, the centering function is also performed in the attached state, so that the first and second magnetic coupling elements are again coupled due to the magnetic force acting between them. In particular in case one of the first and second magnetic coupling elements is a magnetizable element, the self-centering force between the two permanent magnets is not present and the additional centering structure supports the centering of the two coupling partners and thus optimizes the coupling force.
In some embodiments, the cleaning elements disposed on the attachment portion may be made of a soft plastic material such as rubber or thermoplastic elastomer (TPE) or may be made of a harder plastic material such as polyurethane (e.g., PA 6.12). The cleaning elements may have any kind of suitable height, which may be selected to lie between 0.2mm (e.g. in the case of a tongue scraper arrangement) and 30mm, wherein a typical length of the cleaning elements may be in the range of between about 2.0mm to about 15.0mm, optionally between about 5.0mm and 11.0 mm. The cleaning elements may have any suitable diameter, which may be selected to be in a range between about 0.2mm to about 20mm, optionally in a range between about 0.5mm to about 8.0 mm.
Further, it should be noted that the cleaning elements may comprise any suitable cleaning elements and/or may comprise elements for the following uses: massaging the gums, cleaning the tongue, providing chemicals to the oral area such as antimicrobial agents, deodorants, flavors, antiplaque agents, antigingivitis agents, whitening agents, and the like.
For example, in some embodiments, the cleaning elements may comprise tufts of bristles. The tufts can comprise a plurality of individual filaments securely attached to the head. Such filaments may be polymeric and may include, for example, polyamides or polyesters. The longitudinal and cross-sectional dimensions of the filaments of the present invention and the profile of the ends of the filaments may vary. In addition, the hardness, resiliency and shape of the filament ends may also vary. Some examples of suitable dimensions include a length between about 3mm to about 15mm, or any individual value within the range. Further, the filaments may include a substantially uniform cross-sectional dimension between about 100 microns to about 350 microns, or any individual number within this range. The ends of the filaments may be any suitable shape, examples of which include smooth ends, rounded ends, sharp ends. In some embodiments, the filaments may include a dye that may indicate wear of the filaments, as described in U.S. patent No. 4,802,255. Some examples of suitable filaments for use with the brush are described in U.S. patent publication No. 6,199,242. Other suitable examples of bristles include textured bristles, such as single and multi-component bristles (e.g., bristles formed by co-extruding different polymers), crimped bristles, gum massaging bristles, bristles having various configurations (e.g., bristles having multiple tube diameters), and/or combinations thereof.
Other suitable examples of cleaning elements include those described in the following U.S. patents: U.S. patent application publication numbers 2002/0059685; 2005/0000043, respectively; 2004/0177462, respectively; 2005/0060822, respectively; 2004/0154112, respectively; U.S. patent publication nos. 6,151,745; 6,058,541, respectively; 6,041,467, respectively; 6,553,604; 6,564,416, respectively; 6,826,797, respectively; 6,993,804; 6,453,497, respectively; 6,993,804; 6,041,467, respectively; and U.S. patent application serial No. 12/008,073 entitled "TOOTHBRUSHES" filed on 8.1.2008 and 60/928,012 entitled "ORAL HYGIENEIMPLES" filed on 7.5.2007, all of which are incorporated herein by reference in their entirety. Additionally, any suitable configuration of cleaning elements may be utilized. Some suitable examples include those described in the following U.S. patents: U.S. patent publication numbers 5,836,769; 6,564,416, respectively; 6,308,367; 6,108,851, respectively; 6,058,541, respectively; and 5,396,678.
In addition to bristles and/or tufts of bristles, the cleaning elements can also include elastomeric structures, foams, combinations thereof, and the like. For example, the cleaning elements may include elastomeric fins as described in U.S. patent publication No. 6,553,604 and U.S. patent application publication No. 2007/0251040a 1. As another example, the cleaning elements may comprise elastomeric cup-shaped elements as described in U.S. patent publication No. 2004/0154112a 1. In some embodiments, the cleaning elements may comprise a combination of elastomeric elements and bristles. For example, a combination of fins and bristles may be utilized, a combination of elastomeric cups and bristles may be utilized, and/or elastomeric elements may be utilized, either alone or in combination with bristles. Combinations of elastomeric cleaning elements are described in U.S. patent publication No. 2009/0007357a 1.
The cleaning elements and/or massage elements may be attached to the head in any suitable manner. Conventional methods include net-mounting fixation, free tufting of the anchoring agent and injection molding of the tufts. For those cleaning elements that include an elastomer, these elements may be integrally formed with one another or separately formed, such as having an integral base portion and extending outwardly therefrom. The elastomeric element may be injection molded into the head.
In addition to the cleaning elements previously described, the head may include a soft tissue cleanser constructed of any suitable material. Some examples of suitable materials include elastomeric materials; polypropylene, polyethylene, and the like; etc., and/or combinations thereof. The soft tissue cleaner may comprise any suitable soft tissue cleaning elements. Some examples of such elements on toothbrushes and the configuration of soft tissue cleaners are described in U.S. patent application nos. 2006/0010628; 2005/0166344, respectively; 2005/0210612, respectively; 2006/0195995, respectively; 2008/0189888, respectively; 2006/0052806, respectively; 2004/0255416, respectively; 2005/0000049, respectively; 2005/0038461, respectively; 2004/0134007, respectively; 2006/0026784, respectively; 20070049956, respectively; 2008/0244849, respectively; 2005/0000043, respectively; 2007/140959, respectively; and U.S. patent publication numbers 5,980,542; 6,402,768, respectively; and 6,102,923.
Additionally, for those embodiments that include elastomeric elements on a first side of the head and a second side of the head (the second side being opposite the first side), the two-sided elastomeric elements may be integrally molded. For example, a head without an elastomeric element may include an opening that may allow elastomeric material to flow therethrough from a first side of the head to a second side of the head.
The material used to make at least one component, such as a housing of a handle portion or a housing of an attachment portion, may be any suitable plastic or non-plastic material, where typical plastic materials may include at least one of the following: blends of polypropylene (PP), thermoplastic elastomer (TPE), Polyoxymethylene (POM), polyester and polycarbonate such as Xylex, Acrylonitrile Styrene Acrylate (ASA), polybutylene terephthalate (PBT) available from SABIC. Instead of plastic, metal, glass or wood can also be selected as material for manufacturing at least one component of the accessory part.
The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Rather, unless otherwise specified, each of the above dimensions is intended to represent the recited value and a functionally equivalent range surrounding that value. For example, the disclosed dimension "40 mm" is intended to mean "about 40 mm".
Each document cited herein, including any cross-referenced or related patent or patent application, is hereby incorporated by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such invention. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.
While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.