This invention relates to an oral care device with the features of the prior-art portion of claim 1 and to a method of manufacturing it.

Known from the prior art are various oral care devices which are constructed in particular as toothbrushes and have an electrically operable function element such as an LED emitting light. Efforts are made in this context to arrange the LED within the toothbrush head so that said electrically operable function element is fully encapsulated in the toothbrush plastic and hence no moisture-related problems are encountered on the toothbrush head and the electrical components.

An oral care device of the type initially referred to is known in the art from WO 2008/059435. In this device provision is made in the toothbrush bristle zone for an electrically operable function element in the form of an LED which is arranged to protrude from an outer surface of the head in the bristle zone. Efforts to arrange the function element as near as possible to the teeth to be cleaned can lead however to handling problems during oral care.

An oral care device for an electric toothbrush is known from WO 2005/115196 A2 providing centrally in the bristle zone an elastomer element in cup shape with a closed circumferential wall. The purpose of this known elastomer element is to accumulate toothpaste within the walls and thereby enhance the polishing effect of the toothpaste on the tooth surface.

It is an object of the present invention to provide a method and an oral care device of the type initially referred to which, on the one hand, enables an arrangement of the electrically operable function element on the head as near as possible to the oral care site, for example, the teeth or the tongue, but on the other hand guarantees safe and user-friendly handling.

This object is accomplished by an oral care device with the features of claim 1.

By constructing an elastomer element directly adjacent to the function element it is assured that function elements arranged on the outer surface of the head are not experienced as disturbing even if the flexible oral care elements such as cleaning bristles reduce the distance between the outer surface of the head or the function element and the tooth or the tongue while cleaning the tooth or the tongue, respectively. If the toothbrush exerts excessive pressure against the teeth, it can thus be avoided that, depending on the user's brushing technique, the teeth sink into the bristle zone during brushing, occasionally with the unwelcome consequence that the teeth come into contact with the surface of the function element. In addition, the support taken by the oral care elements per se is particularly little if a free space is provided above the function element, so that an easier sinking in is possible on more intensive pressing of the toothbrush against the teeth. Furthermore, the embodiment of the invention enables the electrically operable function element to be arranged in close proximity to the teeth (or the tongue) to be cleaned while at the same time the thickness of the head carrying the oral care elements is kept as small as possible. As such, the toothbrush continues to occupy a small space between the inside of the cheek and the outer surface of the tooth, so that handling comfort is guaranteed.

In another advantageous embodiment, the elastomer element is constructed as a circumferential wall around the function element. This provides for a uniform supporting function covering the entire circumference of the function element by the wall of the elastomer element. The construction of the elastomer element as a circumferential wall affords greater ease of manufacture and enables absorption of force within the elastomer element by neighboring wall sections.

In another advantageous embodiment, the circumferential wall includes lateral recesses arranged on a height with the function element. The provision of the recesses on a height with the function element ensures that toothpaste, instead of accumulating within the elastomer element on the function element, can be drained through the lateral recesses. A closed cup-type structure of the elastomer element is therefore considered as disadvantageous.

In another advantageous embodiment, at least two elastomer elements are arranged laterally adjacent to the function element. For example, the elastomer elements can be constructed as two shells or as two elastomer elements shaped, for example, as rectangles, which on either side are arranged in direct adjacency to the function element and as such also enable a sufficient supporting effect, wherein the interruption between the two elastomer elements produces a gap through which liquid or toothpaste which might deposit on the function element is drained straight away. Instead of two elastomer elements it is also possible to arrange three, four, five, six, seven or more elastomer elements around the function element. These elastomer elements are movable essentially independently of each other or are at least flexible in the end region and may share a base region adjacent to the head or in the head. In another advantageous embodiment, the function element and the elastomer element are integrally made of one piece. Accordingly, the function element and the elastomer element are preferably formed of the same material.

Alternatively, the function element and the elastomer element are made of two materials.

In another advantageous embodiment, the elastomer element includes at least two free ends opposite the outer surface. The free ends are formed, for example, by a wavy structure of the ends or topography of the elastomer element, by indentations or recesses or elastomer elements that are movable or bendable independently of each other. Depending on the dimensioning, the free ends can be adjusted to a certain resilience or be constructed for an optimum cleaning effect on the teeth or the tongue.

In another advantageous embodiment, the function element is arranged adjacent to and/or between the oral care elements. It is thus assured that the properties of the function element take effect in the immediate vicinity of the oral care elements. Alternatively, the function element may be arranged on another outer side of the head which is devoid of oral care elements. This could be of particular interest for a tongue cleaner with function element, for example.

In another advantageous embodiment, the function element is constructed as a light emitting source, in particular as an LED (light emitting diode), as a sensor or an actuator for, for example, a sound, a movement or a vibration. The LED can be used, for example, as a supplier of energy for activating a substance in the toothpaste. Other energy-emitting function elements may be used alternatively. If the function element is constructed as a sensor, then this can be, for example, a motion sensor which detects the 3D motion of the head by means of an inclination sensor, a speed sensor or an acceleration sensor. Also a contact force sensor may be contemplated.

In another advantageous embodiment, the function element is arranged partly in the head and partly projecting therefrom. The elastomer element arranged directly adjacent to the function element thus prevents that, for example, a tooth to be cleaned can hit directly against a function element formed, for example, of a hard plastic material.

In another advantageous embodiment, the elastomer element is made of a thermoplastic elastomer and the head, in particular the areas adjoining the elastomer, of a hard plastic material as, for example, PP, POM, copolyester or PE. In another advantageous embodiment, the function element is secured in the head by a press fit. The outer diameter or the outer geometry of the function element is therefore larger than its receiving opening provided in the head. An encapsulating solution against the ingress of liquid/moisture is thus obtained in simple manner. Other types of securing the function element in the head, for example injection-molding around it, welding, adhesive- bonding or snap-fitting, are likewise possible. Preferably (but not necessarily), the function element is in direct contact with the hard plastic of the head which results in a firm and hard- wearing press fit.

In another advantageous embodiment, the oral care device is constructed as a manual or electric toothbrush and/or the function element as an LED which is arranged in protruding fashion in the cleaning region. Preferably, the LED or the function element is arranged centrally or in the front half, that is, the half of the head at the end remote from the handle. This ensures that also the posterior molars can be illuminated well.

With regard to the method, the above object is accomplished with the features of claim 14. According to the invention, it is proposed injection-molding the head first, followed by connecting the elastomer element to the head. While in this approach the elastomer element may interfere with the subsequent tufting operation of the head, the advantages are, by contrast, that the head and the elastomer element afford ease of manufacture. After the head tufting operation, the function element is fastened adjacent to the elastomer element.

In an advantageous further aspect of this method, the elastomer element is injection- molded onto the head using a multi-component injection-molding technique.

In one variant, this multi-component injection-molding technique also involves injection-molding around the function element. Tufting is then performed in a subsequent operation.

In another advantageous further development of the method, immediately after the tufting operation and before fastening the function element one group of bristle tufts is bent away to the side and another group of bristle tufts is cut to length and/or endrounded. The operation of bending away the fastened bristle tufts relative to other tufts during the cutting operation is performed by means of displacement bars so that the not displaced bristle tufts can have their end sections further treated to any desired form reliably. Since this approach incurs difficulties regarding the elastomer element already connected to the head, the elastomer element is constructed such as not to impede the use of the displacement bars. In a further development of the method, the function element is secured in the head by means of a press fit, with the function element being preferably fastened in the hard plastic of the head. Alternatively, the function element is secured in the soft plastic, for example, of the elastomer element.

Further objects, advantages and application possibilities of the present invention will become apparent from the subsequent description of embodiments with reference to the accompanying drawings. It will be appreciated that any feature described and/or represented by illustration, when used singularly or in any meaningful combination, forms the subject- matter of the present invention, irrespective of their summary in the claims or their back- reference.

In the drawings,

FIG. 1 is a perspective view of the head and the neck portion of an oral care device according to an embodiment of the invention;

FIG. 2 is an enlarged perspective view of the head of FIG. 1 ;

FIG. 3 is a top plan view of the head of the oral care device of FIG. 1 ;

FIG. 4 is a longitudinal sectional view taken along the line A-A of FIG. 3;

FIG. 5 is a cross-sectional view of the head taken along the line C-C of FIG. 3;

FIG. 6 is a perspective view of the elastomer element of the oral care device of FIG. 1 ;

FIG. 7 is a top plan view of the elastomer element of FIG. 6; FIG. 8 is a side view of the elastomer element of FIG. 6; FIG. 9 is a front view of the elastomer element of FIG. 6; and

FIG. 10 is a longitudinal sectional view of a head of an oral care device with electrically operable function element of FIG. 1.

FIG.1 is a perspective top plan view of the head of an oral care device, which according to this embodiment is part of a manual toothbrush. FIG. 2 is a somewhat enlarged perspective view of the head of the oral care device of FIG. 1. In both Figures 1 and 2 as well as in the following Figures, the remaining components of the toothbrush are not shown but are provided as known from the art. A neck portion 2 adjoins the head 1 which has a bristle zone on an upper side for cleaning the teeth. At the breakaway line 3 of FIG. 1 the neck portion continues in a handle portion in which electric leads for operating an electric function element are installed. The handle portion also accommodates an ON/OFF switch, a power supply and other electric devices necessary to operate the electric function element. The oral care elements provided for this embodiment are tufts of cleaning bristles 5 which can be fastened in the head 1 in every manner known in the art. According to the present embodiment, the tufts of cleaning bristles are anchored in the head using the anchor tufting method. Other oral care instruments, for example, elastomer cleaning elements, which are fastened in or molded on the head, can be provided as an alternative or in addition. The outer surface 6 of the head, on which the oral care elements can be fastened, has preferably in the front half of the head or in the front third of the distal end of the head 1 the function element 7 and the elastomer element 8 arranged around the function element. Both the function element 7 and the elastomer element 8 are constructed such that they protrude from the outer surface in the direction of the bristle ends. In an alternative embodiment, the elastomer element and the function element are arranged on another surface which is devoid of tooth cleaning bristles 5. This could be, for example, the rear side or the side of the head 1. In the present case the outer surface 6 is a uniformly plane surface which includes apertures for receiving the oral care elements. According to the present embodiment, the outer surface 6 is also the tufting surface for the bristle tufts. Alternatively, the outer surface 6 can also have a topography differing from the plane surface, with "outer surface 6" being understood to mean the surface into which the oral care elements are inserted and secured in the head 1 adjacent to the elastomer element 8. According to the present embodiment, an LED is provided as function element 7.

As illustrated in FIGS. 1 and 2, the present embodiment includes two outer rows of bristle tufts which are inclined towards the handle, and two inner rows of bristle tufts which are inclined towards the distal end. One front group of bristle tufts is arranged at the distal end to better reach wisdom teeth, for example. The configuration of oral care elements (bristle tufts, for example) can be varied and combined with the elastomer element and the function element in any desired way. According to the present embodiment, the elastomer element 8 is arranged in the front distal end third of the head 1 and is surrounded by bristle tufts on all sides. The function element or LED 7 is fully or, alternatively, partly surrounded by the elastomer element 8.

FIG. 3 shows a top plan view of the head 1 . As is clearly evident from this Figure, the LED 7 is not covered by bristle ends or bristle portions, which enables an unobstructed illumination of the teeth. Provided around the LED is a free region which has a diameter of 2 to 4 mm and is devoid of bristles. This diameter range relates to the optical axis of the LED or an axis angled or offset relative to it. The LED is surrounded by cleaning bristles or oral care elements essentially on all sides.

FIG. 4 shows the head 1 in a longitudinal sectional view along the line A-A of FIG. 3 which corresponds to the longitudinal axis 9. In this embodiment, the LED protrudes beyond the plane outer surface 6 of the head 1 by 1 to 3 mm. Free ends 11 of the elastomer element 8 project from the outer surface 6 by 5 to 9 mm, preferably 6 to 8 mm, approximately. The longest bristles used on the head 1 project away from the outer surface vertically upwardly by 10 to 12 mm so that there is preferably a difference of between 3 and 5 mm between the longest cleaning bristles 12 and the free ends 11. This difference can be provided independently of the above length ranges. Thus, tooth cleaning is performed substantially by the cleaning bristles, whereby the free ends 1 1 of the elastomer element 8 may also perform cleaning functions, depending on the brushing technique used. For optimum resilience or elasticity, the elastomer element 8 should preferably have a hardness of 50 to 80 Shore A. Even on intensive pressing of the bristles against the teeth it is thus not possible to compress the elastomer in its longitudinal dimension to an extent causing the teeth to contact the LED 7.

FIG. 5 is a cross-sectional view along the line 10 or C-C of FIG. 3. As becomes apparent from both FIGS. 4 and 5, a foot region of the elastomer element 8 is arranged in direct adjacency to bristle tufts. The distance between the cleaning bristles nearest the elastomer element and the wall of the elastomer element at the level of the outer surface 6 amounts to between a few tenths of a mm and 2 mm, maximum. The LED 7 is press-fitted within a hard plastic opening of the head 1 . According to this embodiment, the sections of the elastomer element 8 are only connected to the outer surface 6 and not to the mounting hole for the LED, whereby a firm and sealing press-fit is obtained between the hard plastic of the LED and the hard plastic of the head 1 .

FIG. 6 is a perspective view of the elastomer element 8. FIG. 7 shows this elastomer element in a top plan view, FIG. 8 in a front view, and FIG. 9 in a side view. According to this embodiment, the elastomer element 8 includes four free ends 11 , but in variations it may also have two, three or more than four ends 11 . The four free ends 11 are connected to each other in the base area by a circumferential wall, with indentations 13, 14 and 15 being provided between the ends 11. The indentations or recesses or cutouts 13 extend downwardly deeper than the LED 7 protrudes from the outer surface 6 of the head 1 . It is thereby ensured that liquid or toothpaste can be drained on two sides and the optical quality of the LED's radiation performance is not adversely affected. A minor impairment of the optical quality of the LED's radiation performance is considered uncritical. Generally, however, the aim is to optimize the elastomer element 8 and its surrounding geometries to the effect that no major amounts of liquid or toothpaste or none at all can accumulate within the elastomer element 8 and, above all, on the LED 7. The recesses 13 are provided on both sides of the elastomer element 8 as V-shaped notches. The cutout 14 is arranged in an about 90° offset position between the recesses 13 in the wall of the elastomer element, thereby enabling a better emission of light through this opening on the one hand and sufficient flexibility of the ends 11 of the elastomer element 8 on the other hand. Provided on the side close to the distal front end of the head is another cutout 15 which in this embodiment is equally U- or V-shaped and arranged on the outer wall in an about 90° offset orientation relative to and between the recesses 13.

A similar effect can be achieved using an alternative elastomer element 8 which is composed of a plurality of individual rods of either round, oval or rectangular cross-section arranged around the LED, because gaps are likewise formed between these rods which lend these elements sufficient flexibility and allow the liquid to be drained. In this alternative embodiment, the plurality of elastomer elements 8 without a shared foot or base ring of the type shown in FIGS. 6 to 9 are preferably connected with each other through a base or molding area in the head 1 (not shown). The cutouts and recesses 13, 14 and 15 also make sure that directly adjacent bristle tufts do not contact the elastomer element or are deformed thereby.

As becomes apparent particularly from FIGS. 6, 7 and 8, the elastomer element has an additional indent 16 causing the ends 11 to extend in a frusto-conically tapering configuration, rather than cylindrically, relative to the base diameter of the elastomer element 8. The indent 16 serves equally to ensure unhindered movability of the adjacent bristle tufts (in this connection see in particular FIG. 4) on the one hand and manufacturability of the bristle ends adjoining the elastomer element.

The toothbrush is manufactured preferably using the following manufacturing steps and in the sequence identified. First the head 1 is produced applying the plastic injection- molding technique. Depending on whether the elastomer element 8 is injection-molded separately and then secured to the head or whether it is desired to manufacture it integrally with the head, the head 1 is produced optionally with the elastomer element 8 using the two- component injection-molding technique. After the elastomer element 8 is joined to the head, the head is equipped with bristles which in the present case is preferably performed with a method referred to as the anchor wire tufting method (= stapling technique). Other known possibilities of securing the bristle tufts or other oral care elements can be used alternatively to fasten oral care elements to the head. Finally, the function element, which in this case is an LED, is mounted in the head. In the event that the LED is not to be mounted in the head but injection-molding around it is preferred, the sequence of manufacturing steps changes as follows: Injection-molding of the head with molding around the function element, connecting the elastomer element with the head or injection-molding the elastomer element onto the head with a second plastic component, and finally tufting of the head. The head tufting operation preferably includes not only the fastening of the bristle tufts to the head but also the further treatment steps on the bristle ends. These further treatment steps comprise trimming the bristles to length and endrounding the bristle ends. Alternatively or optionally, additional final treatment steps can be performed on the bristle ends. According to this embodiment, the topography of the bristle ends exhibits a structure differing significantly from a flat plane because individual bristle tufts are longer or shorter than adjacent bristle tufts. The bristle tufts of one length remain at their mounting sites for further treatment, that is, for trimming to length and endrounding, whilst all the bristle tufts of other lengths are temporarily bent to the side using so-called displacement bars. Subsequently, the endrounded bristle ends are bent to the side with the displacement bars and the still untreated bristle tufts are cut to their proper length and each single filament of the tuft is endrounded. In this context it will be noted that the elastomer element 8, last but not least owing to its indents and cutouts, is also optimized to the effect that displacement bars can be used without problems for final treatment of the bristle ends.

FIG. 10 shows the head 1 in a longitudinal sectional view. While the elastomer element 8 is not shown in FIG. 10, it should be secured to the head 1 prior to fastening the LED to the head and prior to fastening the bristle tufts to the head 1. FIG. 10 shows the installation of the electrically operable function element in the head 1 schematically. Provided as electrically operable function element is an LED 7 whose connection wires with a wire connection 17 are equipped separately with an encapsulation 18. This protects the electric connections of the LED 7 and the connection wires 17 from moisture ingress. The LED 7 is inserted from the rear through the brush head and a larger cavity 19 so that there is also space for accommodating the encapsulation 18 in the cavity 19. The electric wire 17 is passed through a hollow space in the toothbrush neck which connects the head to the handle and the electric components contained therein. The LED 7 is pressed into the hole 20 preferably with a press fit. According to this embodiment, both the LED 7 and the head 1 are made from a hard plastic material so that a slightly smaller dimensioning of the hole 20 in the head compared to the outer diameter of the LED 7 suffices for guaranteeing said press fit. Alternatively, the LED 7 or the head 1 is formed at least partly from a soft plastic material such as TPE. The head material can be optionally transparent or translucent. The head is sealingly closed from the rear with a cover 21 (see FIGS. 4 and 5) following insertion of the LED 7 and the encapsulation 18. The LED can be fastened in the head by any other method. An alternative production method involves, for example, injection-molding around the LED in the die in which the head 1 is injection-molded. As other alternatives, the LED can be welded in, fitted in, adhesive-bonded or cast in. Also, the LED (or the function element) can be installed from above (that is, from the bristle plane) or between halves of the head.

Similar variants are possible for the construction of the elastomer element 8. Preferably, the elastomer element 8 is injection-molded with the head 1 in one integral piece. Alternatively, the elastomer element is produced in a further injection-molding step, is adhesive-bonded, joined, welded or snap-fitted. The elastomer element can also be made of a different flexible material.