BRUSH FOR A SONIC TOOTHBRUSH WITH LONGITUDINAL AXIS VIBRATION

Description

Technical area

[0001] The invention relates to a brush for a sonic toothbrush with longitudinal axis vibration, comprising an elongated base body which: has a truncated cone-shaped base part with a drive adapter for rotationally fixed coupling to a sonic toothbrush drive with longitudinal axis vibration; a head part with a bristle carrier in which a plurality of bristles are anchored; and which has an elongated neck part connecting the base part and the head part. State of the art

[0002] There are different types of electric toothbrushes.

[0003] From the publications DE 10 2016 011477 (Schiffer), EP 2'454'967 A1 (Braun), WO 2005 046508 A1 (Trisa) and others, the principle of the round brush head is known. This brush head can rotate about an axis parallel to the direction of the bristles and is moved back and forth about this axis. The advantage of this arrangement is that the moving part (namely the round brush head) is very small. It does not require much drive energy and the resulting forces (torques) tend to be small. The disadvantage of this principle is that the bristle movement depends on the distance from the axis of rotation. The closer the bristles are to the axis of the brush head, the smaller the back-and-forth movement. The movement pattern is therefore very inhomogeneously distributed across the bristle field.

[0004] The principle of pendulum motion is known from publications JP H04-43127 (Kao), US 2006 168744 A1 (Butler), US 2012 / 0291212 (Montagnino), and others. The brush oscillates around a pendulum axis that is perpendicular to the handset (drive) and the attached brush, and that intersects the longitudinal axis of the handset and brush at the point where the brush is coupled to the handset. The advantage is that the movement intensity is evenly distributed across the entire bristle area. All bristles are more or less the same distance from the pendulum axis. The disadvantage, however, is that relatively large forces (moments) occur because the brush head, with its mass, is relatively far from the pendulum axis.

[0005] The principle of housing vibration is known from publications JP 2012-161368 (Sanion), DE 299 13 406 U1 (Rowenta), US 6,766,548 B1 (Rowenta), WO 2005 046508 A1 (Trisa), WO 2013 / 104020 A1 (Erskine), and others. A drive in the handset or brush neck generates an undefined vibration that is transmitted to the bristles. The advantage of this design is that there is no need to deal with the technical details of motion transmission. The disadvantage, however, is that the entire housing must be vibrated, and accordingly more drive energy is required than if only a small part needs to be vibrated. Furthermore, the vibration must not be too strong, as this impairs the comfort of holding the handset. Finally, the effective movements of the bristles are unknown and the cleaning effect of this type of undefined and uncontrolled vibration is anything but optimal.

[0006] Another principle is known from the publications WO 2012-151259 A1 (Water Pik), EP 2,548,531 B1 (Trisa), and others. Here, the handset has a coupling pin that rotates back and forth around its longitudinal axis. The brush, which is attached to the coupling pin, has a straight neck and a bristle plate at the end, the bristles of which are perpendicular to the longitudinal axis of the handset or brush neck. The advantage of this geometry is that relatively low forces (moments) occur because the mass (neck, bristle plate) of the brush attachment is relatively close to the longitudinal axis (center of movement). The movement intensity is also distributed relatively evenly across the bristle field. The disadvantage of this principle, however, is that the bristles only perform a one-dimensional movement (back and forth).On the one hand, the foaming effect of the toothpaste is unsatisfactory and, on the other hand, the advantage of the circular and thus gentle yet efficient movement, which specialists have been teaching for decades as being beneficial in connection with the manual toothbrush, is missing.

[0007] It is well known that the cleaning effect of manual toothbrushes depends on the hardness of the bristles. Bristles of different hardness have different cleaning effects and different damage potentials depending on their intended use. These effects are well known among experts and are regularly incorporated into patient consultations.

[0008] Sonic toothbrushes are very comfortable for the user and are also considered efficient because the electrically powered brush makes the movements much faster than you can do by hand.

[0009] The assumption with sonic toothbrushes has so far been that the higher the frequency of the motor and the greater the cleaning movement of the bristles, the better the cleaning.

[0010] WO 2017 / 050612 A1 (Curaden) discloses a sonic toothbrush with an angled brush head. The forward angle of the sonic toothbrush allows for better access to various areas of the teeth. The angle also ensures that the brush filaments oscillate with a greater amplitude perpendicular to the brush's longitudinal axis. The preferred operating frequency is 2000 to 8000 hertz. However, frequencies can also be higher, for example, 10 kHz, 50 kHz, or even lower, for example, 200 Hz or 500 Hz.

[0011] US 2012 / 0291212 A1 discloses an ultrasonic toothbrush that has two parallel channels running perpendicular to the brush's longitudinal axis to increase the resonant frequency. The frequency is increased in a forward-backward direction when the two channels are positioned at the front. If the channels are positioned on the left and right sides of the brush neck, the frequency increases in a lateral direction. Disadvantages

[0012] There is still a lack of sufficient understanding of the cleaning performance of sonic toothbrushes. Current knowledge regarding the cleaning effectiveness of manual toothbrushes cannot be transferred to the highly dynamic situation of a sonic toothbrush. Description of the invention

[0013] The object of the invention is to create a toothbrush for sonic toothbrushes belonging to the aforementioned technical field, which offers an improved cleaning effect that is particularly gentle on the gums. In particular, a defined and controlled two-dimensional movement of the bristles is to be generated.

[0014] The solution is defined by claim 1. The base body has a bending angle such that a geometric foot part longitudinal axis and a geometric head part alignment axis enclose an angle γ in the range of 5° to 12°. Furthermore, a geometric bending position in the base body has a distance from an end surface of the foot part of at least 60% of the total length of the base body.

[0015] The sonic toothbrush according to the invention essentially generates an oscillation of the brush around its longitudinal axis, i.e., the longitudinal axis of the base (defined here as the x-axis). The bristles therefore primarily perform a wiping motion perpendicular to the aforementioned longitudinal axis. A particular advantage of the brush according to the invention is that it has a bending angle position that results in a sufficiently large deflection (also called eccentricity) of the head section, so that a certain oscillation also occurs in the direction of the longitudinal axis. This results in a two-dimensional movement that can be described as a "figure-8" movement. This is particularly advantageous in several respects.

[0016] The combination of the special bending angle, which according to the invention is neither too small nor too large, and the bending angle position according to the invention, which is not too close to the base, results in a deflection (or eccentricity with respect to the base's longitudinal axis) and a leverage effect, which leads to a slight nodding movement of the brush head during operation. This results in the aforementioned two-dimensional "figure-8" movement of the bristle tips.

[0017] However, one advantage of this brush design is that the brush also performs a slight "noddling" motion toward the bristles. This pushes the mixture of saliva and toothpaste "forward" into the interdental spaces. This is especially important for single-tuft toothbrushes, which are specifically designed for better interdental cleaning.

[0018] The invention is based on the following basic features: a) The brush has a base section on which an adapter to the handset, a so-called drive adapter, is formed. The adapter is geometrically designed to be connected in a rotationally fixed (but replaceable) manner to a coupling part (e.g. pin) of the sonic toothbrush drive. The sonic toothbrush drive generates a longitudinal axis vibration that is transferred to the brush. The drive adapter defines a geometric base section longitudinal axis (x) of the brush. This longitudinal axis is normally the direction in which the brush can be attached to the handset. b) The brush also has a head section with a bristle carrier in which a large number of bristles are anchored (bristle field). The head section is essentially the upper end of the brush (whereas the base section forms the lower end). The head section defines a head section alignment axis. The bristles anchored in the head protrude, for example, perpendicular to the head section alignment axis.Typically, but not necessarily, the bristles are perpendicular to the head section alignment axis. c) The base body has a neck section between the foot section and head section. The neck section connects the foot section and head section. Its cross-section is tapered compared to the foot section. This means that if you look at the foot section in cross-section (relative to the foot section's longitudinal axis), the dimensions in the x or y direction are smaller than the cross-section of the neck section (i.e., perpendicular to the neck section's longitudinal axis). "Tapered cross-section" refers to the cross-sectional area. It is therefore not necessary for the dimensions in the x and y directions to be smaller.

[0019] In a first variant, the bristle carrier has several tufts, each with a large number of bristles. In a second variant, the bristle carrier has exactly one tuft with a large number of bristles (single-tuft variant).

[0020] However, the bristles can also be indirectly anchored to the surface of the bristle carrier, especially if the brush is designed as an interdental brush. In a third variant, the bristle carrier has a twisted or folded wire loop on its surface, with the bristles clamped between the strands. In this case, the head section's alignment axis is preferably oriented perpendicular to the wire alignment.

[0021] The geometric bending position is defined by an intersection point between the geometric foot part longitudinal axis and the geometric head part alignment axis. Therefore, the geometric bending position does not necessarily require a bend-like (or knee-like) change in the direction of the base body. Preferably, the geometric bending position is located within the base body. The shape of the base body does not necessarily have to include a visually recognizable bend, but can, for example, be arcuate. In variants, the geometric bending position can also be located outside the base body. Further variations are known to those skilled in the art.

[0022] The distance between the end face of the foot section and the bending position is measured along the foot section's longitudinal axis. The total length of the base body is also measured along the foot section's longitudinal axis.

[0023] According to the invention, the geometric bending position has a relatively large distance from the head part in order to achieve, in conjunction with the angle γ (gamma) between the geometric foot part longitudinal axis and the geometric head part alignment axis of 5° to 12°, a particularly optimal vibration behavior for cleaning the teeth. The larger the angle is selected, the greater the deflection of the head part from the foot part longitudinal axis (eccentricity). Likewise, the eccentricity increases when the bending position is further away from the head part. However, it has been shown that the two parameters (bend position and angle) do not influence the vibration behavior to the same extent and in the same way, so that with regard to the cleaning effect, for examplean increase in the angle cannot be directly compensated by a smaller distance between the bending position and the head part, since the 2-dimensional or 3-dimensional vibration pattern of the head part reacts differently to the two parameters.

[0024] According to the invention, the distance between the geometric bending position and the end surface of the foot part is at least 60% of the total length of the base body. This defines a particularly optimal range for the geometric bending position, which, according to experiments, leads to particularly advantageous 2-dimensional and 3-dimensional vibration patterns. This allows for particularly effective yet gentle tooth cleaning.

[0025] According to a special embodiment, the distance between the geometric bending position and the end surface of the foot section is a maximum of 75% of the total length (L) of the base body. Within this upper-limited range, the inventive bending angle of 5° to 12° allows for a sufficiently strong "8" movement, allowing for considerable design flexibility regarding the geometric dimensions of the neck section and head section.

[0026] According to the invention, the head section is plate-shaped and the neck section is rod-shaped. Thus, the head section is wider in cross-section (i.e., in the plane perpendicular to the head section alignment axis) in one direction (e.g., the y-direction) than in the other direction (e.g., the z-direction). The shape of the cross-section can be, for example, rectangular, trapezoidal, or oval.

[0027] The neck section may be circular, oval, square, hexagonal, octagonal, trapezoidal, or a geometric approximation or modification of such a shape. The cross-sectional shape does not need to be rotationally symmetrical.

[0028] According to a first particular embodiment, the head part is at least about twice as wide as the neck part.

[0029] According to a second special embodiment, the head section is at most approximately 1.5 times as long as the neck section. This can also be combined with the previously mentioned embodiment.

[0030] According to a third particular embodiment, the head portion, in a cross-section spanned by the longitudinal axis of the brush and the head alignment axis, is approximately the same thickness as the neck portion. If the head portion is plate-shaped, then the neck portion is approximately the same thickness as the head portion plate.

[0031] In one embodiment, the head section is at least about twice as wide and at most about 1.5 times as long as the neck section. Particularly preferably, the head section is between 2 and 3 times as wide and preferably between 0.5 and 1.5 times as long as the neck section. The relatively slender neck section, compared to the head section, achieves particularly good vibration behavior and thus optimal cleaning of the teeth.

[0032] In variations, the head section can also be less than twice as wide and more than 1.5 times as long as the neck section.

[0033] In a particular embodiment, the head portion has a mass that is greater than the mass of the neck portion; in particular, the head portion has a mass that is preferably more than 30%, particularly preferably more than 50%, greater than the mass of the neck portion. This mass distribution can be achieved either through appropriate geometric dimensions or through different materials, or through both.

[0034] The relatively large mass of the head compared to the neck allows for a slight nodding motion of the brush head (a movement in the z-direction) to be optimized when using the toothbrush. The larger mass increases the momentum of the nodding motion, which can reinforce the two-dimensional "8" motion and, in turn, better reach the interdental spaces. This is particularly advantageous, but not exclusively, with the single-tuft version or interdental brush.

[0035] In variants, the head section can also have a mass that is less than 30% greater than the mass of the neck section; in particular, the masses of the head section and the neck section can also be approximately the same. This is the case, for example, if the head section is the same thickness as the neck section, and if the neck section is three times as long as the head section, and the head section is three times as wide as the neck section.

[0036] Preferably, the base section is approximately the same length as the head section. This ensures that the base section is sufficiently large to ensure a stable attachment to the sonic toothbrush drive (e.g., with a long adapter channel for a correspondingly long handset pin). The vibration and thus the kinetic energy of the drive are efficiently transferred to the head section via the neck section.

[0037] In one particular design, the foot section is shorter than the head section; in particular, the foot section is approximately half as long as the head section. This creates more design freedom for the neck section. If, in such a design, the drive adapter is also designed as a slender pin on the brush that inserts into an adapter channel in the handset, the stable attachment to the sonic toothbrush drive is concealed.

[0038] In some variants, the foot section can also be longer than the head section.

[0039] Preferably, the neck section has a transverse dimension that is no more than one-quarter of the length of the neck section. The transverse dimension is defined as a diameter perpendicular to the geometric alignment axis or perpendicular to the foot section's longitudinal axis. Where the neck section connects to the head section, the head section's alignment axis is decisive, and where the neck section connects to the foot section, the foot section's longitudinal axis is decisive. The neck section is thus deliberately kept slim to support the head section's vibration behavior, particularly the vibration behavior in the plane (the "8" movement) and the pitching movement.

[0040] In some variants, the transverse dimension can also be more than a quarter of the length of the neck piece. This can be useful, for example, if a particularly flexible or elastic material is used for the neck piece.

[0041] Preferably, the base body is made of a load-bearing material with a Young's modulus of less than 8,000 MPa. In particular, the Young's modulus is in the range of 2,000 MPa to 6,000 MPa. This results in a base body that is sufficiently elastic to optimally transmit vibrations while also being sufficiently stable.

[0042] Preferably, the modulus of elasticity is at least 2500 MPa, in particular at least 3000 MPa. This ensures a base body that is sufficiently strong to optimally transmit the longitudinal axis vibrations.

[0043] In certain variants of the invention (e.g. at rather small bending angles in the range of 8°), the modulus of elasticity can tend to be lower (e.g. 2000 MPa to 3000 MPa) than at large bending angles (e.g. at 15°).

[0044] Another special design is characterized by the fact that the modulus of elasticity of the supporting material (or materials) of the base body is in the range of 4000 MPa to 6000 MPa.

[0045] If the mass of the head part is relatively large in relation to the cross-section of the neck part, then an elastic modulus in the range of 5000 MPa to 6000 MPa is advantageous.

[0046] Preferably, the base body consists essentially of a single piece made of a single material. This allows for particularly cost-effective production of the base body. It also enables particularly optimal vibration behavior, since no boundary transitions between different materials disrupt the vibration behavior, especially 2-dimensional or 3-dimensional vibration behavior, where such a boundary transition is bent in different directions by the vibration pattern.

[0047] For the purposes of the invention, a one-piece base body made of a supporting material is also referred to if the surface of the brush is coated or encased in a non-supporting material. For example, in a one-piece base body, areas made of a material with increased roughness or surface grip can be provided on the base part, so that the brush can be more easily removed from the drive pin with the fingers.

[0048] According to a special embodiment, the base body is essentially formed by two material parts joined together. For example, if the base part is molded from a different plastic than the neck and head of the brush, a very rigid plastic (with a high modulus of elasticity) can ensure that the coupling to the drive pin on the handset optimally transfers the drive movement to the brush. However, the neck can be designed to be sufficiently elastic using a less rigid material (the modulus of elasticity of the neck part material is lower than the modulus of elasticity of the base part).

[0049] Another special design is characterized by the fact that the base body is essentially formed by three materially bonded parts. For example, the base body can consist of two materially bonded parts of different strengths in the longitudinal direction. Furthermore, it is conceivable for the head section, neck section, and foot section to be made of different materials. The requirements for the head section are different from those for the foot section, which can be optimized by selecting the right material.

[0050] A base body made of two or three materially bonded materials is produced, for example, by modern plastic injection molding processes with two or three materials.

[0051] Even on the base body with the two or three supporting material parts, non-supporting (e.g. soft) coating layers can be present in order to achieve certain functions (e.g. protection when the back of the brush comes into contact with the teeth).

[0052] Preferably, the head section has a deflection of 10% - 20% relative to the length of the brush. In this case, the deflection is defined as the ratio between the distance from the center (center of gravity) of the head section to the adapter's longitudinal axis, divided by the total length L (in the x-direction) of the base body. The deflection can be considered the "eccentricity of the head section with respect to the adapter's longitudinal axis." The deflection is crucial for the vibration pattern: it has been determined that with a deflection of 10% - 20%, the "figure-8" movement is particularly pronounced.

[0053] The deflection can also be less than 10% or greater than 20%. For brushes with a short overall length, the deflection is preferably selected in the range of 20% to prevent the head from becoming too small. For brushes designed for high operating frequencies (e.g., above 240 Hz), the deflection is preferably selected in the range of 10%, because at higher frequencies, the head's imbalance could otherwise become too large.

[0054] According to the invention, the bristles protrude essentially perpendicularly from the brush's head section alignment axis. The angle between the foot section's longitudinal axis and the bristle direction is then 90° minus the bend angle γ (gamma). For example, with a bend angle of γ = 9°, this results in 90° - 9° = 81°.

[0055] The bristles are anchored, for example, to the main surface of the plate-shaped head. However, in a single-tuft brush, the head can also be rod-shaped, with the single tuft anchored in a cylindrical recess (e.g., a blind hole).

[0056] Preferably, a geometric base section longitudinal axis and a geometric head section alignment axis enclose an angle γ (gamma) in the range of 7° to 10°. This angular range has proven particularly advantageous in experiments, allowing a particularly ideal oscillation pattern to be achieved for tooth cleaning. Experiments have shown that this results in a particularly advantageous oscillation pattern, particularly the "8" movement, allowing for particularly gentle tooth cleaning with the brush. The angular range, in conjunction with the deflection or eccentricity of the head section relative to the total length of the brush, between 10% and 20%, has also proven particularly advantageous and has also led to particularly good cleaning results with optimal ergonomics.

[0057] The angle range of 7° - 10° in combination with a deflection of 10% to 20% leads to a good dynamic of the oscillation of the brush head in the sense of the desired "figure 8 movement".

[0058] In a special design, the neck section is tapered in cross-section compared to the head section. This means that the head section is wider and / or thicker (as viewed perpendicular to the head section's alignment axis) than the neck section. This makes the neck section mechanically less rigid than the head section (provided the base body is made of one or more materials with approximately the same modulus of elasticity).

[0059] A sonic toothbrush with longitudinal axis oscillation according to the invention comprises a brush according to the invention and a handset with a brush coupling for releasably attaching the brush to the handset and with a drive that generates a longitudinal axis oscillation at the brush coupling. The drive can, for example, comprise a piezo drive, a magnetic drive, and / or an electric rotary drive. A piezo drive is particularly preferred, in particular due to its simple design, particularly compact construction, and precise controllability.

[0060] The drive is preferably designed to generate a longitudinal axis oscillation frequency in the range of 150 Hz to 400 Hz. Since the brush generates a 2-dimensional or 3-dimensional movement pattern, the longitudinal axis oscillation frequency is set relatively low, allowing more time to perform multiple changes of direction per oscillation, e.g., in a figure-8 movement. The longitudinal axis oscillation frequency is advantageously no higher than 300 Hz. If the frequency is too high, the base body can no longer transmit the longitudinal axis oscillation generated by the drive to the brush head. This can lead to internal torsional movements, which can cause the head to, for example, only execute every other oscillation.

[0061] The longitudinal axis vibration frequency can also be less than 150 Hz, e.g. 120 Hz.

[0062] Preferably, the drive is designed to generate a longitudinal axis oscillation with an amplitude (deflection relative to a rest position) of less than 3°, in particular in the range of 1° to 3°. This means that the foot part is periodically rotated (moved back and forth) by the angle around the foot part's longitudinal axis. In variants, the amplitude can also be greater than 3°.

[0063] Further advantageous embodiments and combinations of features of the invention emerge from the following detailed description and the entirety of the patent claims. Short description of the drawings

[0064] The drawings used to explain the embodiment show: Fig. 1 is a schematic representation of a top view of a brush; Fig. 2 is a schematic representation of a side view of the brush; Fig. 3 is a schematic representation of a back view of the brush; Fig. 4 is a schematic representation of a top view of a sonic toothbrush comprising the brush; Fig. 5a is a schematic side view and a top view of a sonic toothbrush; Fig. 6 is a schematic representation of a side view of a sonic toothbrush with exactly one tuft; Fig. 7 is a schematic representation of the "8" movement according to the invention; Fig. 8 is a schematic representation of the angular amplitude of the longitudinal axis oscillation; Fig. 9 is an embodiment with an oval brush head; Fig. 10 is an embodiment of a single-tuft brush with a rear bristle field; Fig. 11 is an embodiment of a single-tuft brush with a front bristle field.

[0065] In principle, identical parts in the figures are provided with identical reference symbols. Ways to implement the invention

[0066] The Figure 1 shows a schematic representation of a top view of a brush 10. The brush 10 comprises a truncated cone-shaped base part 11, a rod-shaped neck part 12 adjoining the truncated cone-shaped base part 11, and finally a plate-shaped head part 13 adjoining the neck part 12. These three parts form the base body of the brush.

[0067] The truncated cone-shaped base part 11 comprises a drive adapter. In the present case, this is essentially formed by a channel-shaped receptacle 14 into which a pin of the handset of the sonic toothbrush can be inserted and locked (see below for Figure 4). The brush 10 has a base part longitudinal axis 20, which is aligned coaxially with the receptacle 14, or coaxially with the pin during operation of the sonic toothbrush. This longitudinal axis defines the x-axis of the xyz coordinate system used here. In other words: the drive adapter defines the geometric base part longitudinal axis (x) of the brush.

[0068] In the Figure 1 the bristle field 17 of the head part 13 is also visible, which in the present case has several (e.g. 20 - 40) tufts, each with a large number (e.g. 100 - 200) of bristles.

[0069] According to a preferred embodiment, the head section 13 is teardrop-shaped when viewed from the front. This means that its shape gradually widens – starting at the transition to the neck section – almost to the upper end of the head section, where it ends in a rounded final contour. With this shape (for a given length of the bristle field in the x-direction), the center of gravity of the head section 13 is closer to the end of the brush. This can enhance the eccentric effect at the specified operating frequency and thus also the "figure-8" movement.

[0070] The main surface of the plate-shaped head part 13 extends essentially transversely to the x-axis in the y-direction.

[0071] On the bristle field 17, a figure-8 positioned in the y-direction is also depicted with reference numeral 23. The figure-8 illustrates the movement that is executed in the plane during operation due to the selected material property (Young's modulus), the angle between the geometric foot part longitudinal axis 20 and the geometric head part alignment axis (see below), and the bending position.

[0072] In addition to the figure-8, the brush also performs a slight nodding motion with the head section 13—this motion is essentially perpendicular to the figure-8, i.e., essentially in the z-direction. In a preferred embodiment, the bristles are thus moved in three dimensions (x, y, z).

[0073] The Figure 2 shows a schematic representation of a side view of the brush 10. In this figure, in addition to the geometric foot part longitudinal axis 20, the geometric head part alignment axis 21 is also visible. In the illustration according to Figure 1 The foot part longitudinal axis 20 and the head part alignment axis 21 are arranged one behind the other. The head part alignment axis 21 is essentially the longitudinal axis of the head part. The two axes intersect at the geometric bending position 22. In the present embodiment, the geometric foot part longitudinal axis 20 and the geometric head part alignment axis 21 form an angle γ (gamma) of 10°. The geometric bending position 22 is at a distance K from the end surface of the foot part 11 of 50% of the total length L of the brush 10. This combination of the angle to the bending position 22 creates a brush 10 with which particularly effective and gum-friendly cleaning of the teeth is possible.

[0074] As the combination of Figures 1 and 2As can be seen, in the present embodiment, the head part 13 is plate-shaped and the neck part 12 is rod-shaped. In the projection of the base body onto the xz-plane, the head part 13 and the neck part 12 have the same transverse dimension (i.e. the same thickness). In the projection onto the xy-plane (front view according to Figure 1 ), the head section 13 is approximately three times as wide (y-direction) as the neck section 12. The length (x-direction) of the head section is approximately one-third greater than the width (y-direction). For example, the neck section 11 is one-third as wide and 1.5 times as long as the head section 13.

[0075] The neck part 12 is tapered compared to the head part 13 and the foot part 11. In the present example, the neck part 12 is in at least one of the side views (here in the z-direction according to Figure 1 viewed) less wide than the headboard 13.

[0076] In the present example, the base body of the brush 10 has as its supporting material a glass fiber reinforced polypropylene Borealis GB311U with an E-modulus of around 3500 MPA (Tensile Strength at yield = 97 MPa; Elongation at Yield = 2.8%; E-modulus = Tensile Strength at Yield / Elongation at Yield).

[0077] The deflection is determined by the ratio of distance A to the length L of the brush. The distance A corresponds to the distance from the front center of the head section (which here corresponds to the center of the bristle field 17) to the foot section's longitudinal axis 20 (see Figure 2 ). In this example, the deflection is 14%.

[0078] The bristles are arranged in several clusters and protrude vertically from the main surface of the plate-shaped head section. In this case, they are perpendicular to the y-direction and extend in the xz-plane. In the present embodiment, the bristles are attached to the front of the head section (or the front side 27 of the brush), i.e., they point slightly downward toward the adapter surface (yz plane) of the base section.

[0079] The Figure 3 shows a schematic representation of a back view of the brush 10 according to the Figures 1 and 2As can be seen from the figures, the base body has a different material on the back side 26, which is soft and provides protection (protective layer, protective coating) when the back of the brush comes into contact with the teeth. This material is non-load-bearing and can therefore have an elastic modulus outside the elastic modulus range of 2000-6000 MPa according to the invention. The load-bearing material is visible on the front side 27 and makes up a significant portion of the cross-section of the base body.

[0080] The Figure 4shows a schematic representation of a top view (z-direction) of a sonic toothbrush comprising the brush 10 and a handset 16 with a pin 15. The brush 10 is attached to the pin 15 so that the brush is detachable, rotationally fixed, and axially fixed. The handset 16 rotates the pin 15 back and forth at a frequency of, for example, 180 - 270 Hz with an amplitude of, for example, 2° (relative to a rest position) about the longitudinal axis of the pin 15 (which corresponds to the longitudinal axis of the handset 16). The brush thus rotates back and forth about the base part's longitudinal axis 20 (x-axis).

[0081] The Figure 5ashows a schematic representation of a side view of a sonic toothbrush 10. The sonic toothbrush 10 comprises a handset 16 and a brush 10. The drive of the handset 16 is designed as a piezoelectric drive (not shown), which generates an oscillation of the brush 10 about the x-axis 20 (longitudinal axis of the handset). Thus, during operation, the brush 10 executes a rotational oscillation about the x-axis 20 relative to the handle. Due to the inventive deflection of the head part 13, an imbalance arises, which has a movement component in the Y-direction 24 and / or in the Z-direction 25 (see below, Figure 5b ). This effect is controlled by the appropriately angled bend in the brush neck, the appropriately selected modulus of elasticity, and can be adjusted by other geometric design features of the brush (such as bend angle position, deflection, mass distribution, and other features according to the particular embodiments of the invention).

[0082] The Figure 5b shows a schematic plan view of a personal care device according to Figure 5a . In this illustration, the Z-direction 25 is visible. It runs essentially in the direction of the bristles. As can be seen from the figure, the handset is significantly larger than the brush. Only in this way can it generate a longitudinal axis vibration (instead of an undefined or undirected vibration movement, as is the case with conventional sonic toothbrushes).

[0083] The Figure 6 shows an embodiment of the sonic toothbrush, which comprises exactly one tuft 18. The tuft 18 is arranged at the rear of the head portion 13. The head portion is essentially tilted backward.

[0084] The Figure 7shows a schematic representation of the inventive "8" movement. The "8" movement in this case has the shape of a one-sidedly flattened "8," with an axis of symmetry (X-axis) running through the center 27 of the "8." The two loops 28a, 28b of the "8" extend in the y-direction. However, the invention is not limited to this exact form of the "8" movement; the exact form of the movement ultimately depends on the parameters of the brush head and the vibration generated by the handset motor.

[0085] The Figure 8 illustrates the amplitude of the longitudinal axis oscillation movement. The x-axis is perpendicular to the plane of the drawing. The plate-shaped head part 13 (shown without bristles) pivots around the x-axis by the angle α (alpha). (The bristles extend in Figure 8 (upward in the z-direction). The main component of the pivoting movement (and thus the bristle wiping movement) is in the y-direction. The angle α (alpha) is preferably 2°.

[0086] The Figure 9 shows a brush 10 with a plate-shaped oval head 13. The longitudinal axis of the oval shape runs essentially in the x-direction and the transverse axis in the y-direction. The center of the head 13 is further away from the upper end of the brush 10 than in the drop-shaped head according to Figure 1 .

[0087] Figure 10 shows a brush with a bending angle γ (gamma) of 14° and a distance K of the geometric bending position 22 to the end surface 29 of the foot part 11 of 75% based on the length L of the brush.

[0088] The base section 11 tapers from the end surface 29 to the transition into the neck section 12. The base section 11 can be, for example, truncated cone-shaped or truncated pyramid-shaped, with a concave profile in longitudinal section. Thus, the center of gravity of the base section 11 is closer to the end surface 29 than in a comparable base section with straight profile lines.

[0089] In the illustrated embodiment, the neck part 12 takes up approximately half the length (L) of the brush. Figure 10 As illustrated, the neck portion 12 does not necessarily have to have a constant cross-section along its entire length. It may well have a changing contour.

[0090] The head portion 13 is formed by the extension of the neck portion 12. In the present example, the head portion 13 has essentially the same transverse dimensions (viewed in a section perpendicular to the head portion alignment axis 21) as the neck portion 12. The bristle array 17 is positioned laterally on the head portion 13. The bristles thus protrude perpendicular to the head portion alignment axis 21.

[0091] Figure 11shows an embodiment in which the base section 11 is essentially formed by a pin 30 as a drive adapter. The neck section 12 is rod-shaped and occupies, for example, 90% of the brush length. The head section 13 is the part in which the bristle field 17, here in the form of a single tuft, is anchored. The pin 30 is inserted into the handset in the x-direction for rotationally fixed coupling to a sonic toothbrush drive with longitudinal axis oscillation, with the drive adapter defining the geometric longitudinal axis (x) of the brush's base section.

[0092] A brush according to Fig. 11 For example, it is made of a material with a Young's modulus of approximately 4600 MPa. An example of such a material is LNP ULTEM ®< EXCP0096 Polyetherimide, 30% Carbon Fiber Reinforcement, 10% PTFE Lubricant (Tensile Strength at Yield = 163 MPa, Elongation at Yield = 3.5%, Tensile Strength / Elongation = 4650 MPa). Variations of the embodiments:

[0093] In further embodiments not shown, the brush 10 has an interdental brush for cleaning the spaces between the teeth instead of the bristle field 17.

[0094] In summary, it can be stated that according to the invention a brush for a sonic toothbrush drive is created, which leads to a particularly advantageous movement of the head part for an effective cleaning of the teeth while protecting the gums.

Claims

1. Brush (10) for a sonic toothbrush with longitudinal axis vibration comprising an elongated base body having a) a frustoconical base portion (11) having a drive adapter (14) for rotation-fixed coupling to a sonic tooth brush drive with longitudinal axis vibration, said drive adapter (14) defining a geometric base portion longitudinal axis (x) of the brush, b) a head portion (13) with a head portion alignment axis (21) and a bristle support in which a plurality of bristles are anchored, whereby the bristles extend substantially perpendicularly away from the head portion alignment axis (21) of the brush (10), c) and having a neck portion (12) of tapered cross-section compared to the base portion, connecting the base portion (11) and the head portion (13), whereby the head portion (13) is plate-shaped and the neck portion (12) is rod-shaped, whereby d) the base portion forms a kink angle such that a geometric base portion longitudinal axis (20) and a geometric head portion alignment axis (21) include an angle γ in the range of 5° to 12°, and characterized in that e) a geometric kink position (22) in the base portion has a distance (K) to an end face of the base portion (11) of at least 60% of a total length (L) of the base body.

2. Brush (10) according to claim 1, characterized in that the distance of the geometric kink position (22) to the end face of the base portion (11) is at most 75% of the total length (L) of the base body.

3. Brush (10) according to any one of claims 1 to 2, characterized in that a) the head portion (13) is at least about twice as wide as the neck portion (12), and / or b) the head portion (13) is at most about 1.5 times as long as the neck portion (12) and / or c) the head portion (13) is approximately the same thickness as the neck portion in a cross-section spanned by the longitudinal axis (x) and the head alignment axis.

4. Brush (10) according to any of preceding claims, characterized in that the head portion (13) has a mass which is greater than a mass of the neck portion (12), in particular the head portion (13) has a mass which is at least 30%, particularly preferably at least 50%, greater than the mass of the neck portion (12).

5. Brush (10) according to any of preceding claims, characterized in that the base portion (11) is approximately the same length as the head portion (13).

6. Brush (10) according to any of preceding claims, characterized in that the neck portion (12) has a transverse dimension that is not more than a quarter of a length of the neck portion (12).

7. Brush (10) according to any of preceding claims, characterized in that the base body comprises a load-bearing material having a Young's modulus of not more than 6000 MPa and not less than 2000 MPa.

8. Brush (10) according to claim 7, characterized in that the modulus of elasticity is at least 2500 MPa, in particular at least 3000 MPa.

9. Brush (10) according to claim 7, characterized in that the base body consists essentially of one piece of one material.

10. Brush (10) according to one of claims 7 or 8, characterized in that the base body is essentially formed by two or by three parts of material which are joined by material bonding.

11. Brush (10) according to any one of claims 1 to 10, characterized in that the head portion (13) has a deflection of 10% - 20% with respect to a length of the brush (10).

12. Brush (10) according to any one of the preceding claims 1 to 11, characterized in that the geometric base portion longitudinal axis (20) and the geometric head portion alignment axis (21) include an angle γ in the range of 7° to 10°.

13. Brush (10) according to any one of claims 1 to 11, characterized in that the neck portion (12) is cross-sectionally tapered in comparison to the head portion.

14. Sonic toothbrush with longitudinal axis vibration, comprising a) a brush (10) according to any one of claims 1 to 9; and b) a hand apparatus having a brush coupling for releasably attaching the brush (10) to the hand apparatus and having a drive (16) which generates a longitudinal axis vibration at the brush coupling.

15. Sonic toothbrush according to claim 14, characterized in that the drive (16) is adapted to generate a longitudinal axis vibration frequency in the range of 150 Hz to 400 Hz.

16. Sonic toothbrush according to claim 14 or 15, characterized in that the drive (16) is designed to generate a longitudinal axis vibration with an amplitude of less than 3°, in particular from 1° to 3°.