BRUSH FOR A SONIC TOOTHBRUSH WITH LONGITUDINAL AXIS OSCILLATION

Abstract

A brush includes an elongated base body having a base portion that provides an adapter for rotationally fixed coupling to a sonic toothbrush drive in order to pivotally oscillate the brush about a base portion longitudinal axis. A bristle support is formed on a head portion of the elongate base body, and bristles extend from the head portion at least substantially perpendicularly. A neck portion connects the base portion and the head portion. The elongated base body bends at a bend angle ? formed by the base portion longitudinal axis and a head portion orientation axis in the range of 7? to 17?. The bristle support has a deflection A in the range of 5% to 15% with reference to a length L of the base body. At least a portion of the bristles has a value ?.sub.x in the range from 0.1 to 10 MPa.

Claims

1. A brush for a sonic toothbrush with longitudinal axis oscillation, having: an elongate base body having a base portion, a neck portion and a head portion, an adapter for rotationally fixed coupling to a sonic toothbrush drive of the sonic toothbrush in order to pivotally oscillate the brush about a base portion longitudinal axis, the adapter being provided on the base portion, a bristle support provided on the head portion, and a plurality of bristles anchored in the head portion, wherein: the neck portion is disposed between the base portion and the head portion, the head portion has a head portion orientation axis, the base body includes a bent portion having a bend angle ? formed by the base portion longitudinal axis and the head portion orientation axis in the range from 7? to 17?, the bristle support has a deflection in the range of 5%-20% with reference to a length (L) of the elongated base body, the bristles extend at least substantially perpendicular to the head portion orientation axis, at least a portion of the bristles has a value ?.sub.k in the range from 0.1 to 10 MPa as calculated according to the following equation: ${?}_k=\frac{{?}^3}{L^2}.Math.E.Math.r^2$ ?=number Pi(=3.14), E=Young's modulus of the bristles, r=half the diameter of the bristle, and L=length of the bristle.

2. The brush according to claim 1, wherein the value ?.sub.k is at most 4 MPa.

3. The brush according to claim 1, wherein the value ?.sub.k is at least 1 MPa.

4. The brush according to claim 1, wherein the value ?.sub.k is in the range from 1 MPa to 4 MPa.

5. The brush according to claim 1, wherein the bristles have a Young's modulus in the range from 1000 MPa to 3500 MPa.

6. The brush according to claim 1, wherein the bristles have a Young's modulus of not more than 2000 MPa.

7. The brush according to claim 1, wherein the bristles have a Young's modulus in the range from 2500 MPa to 3500 MPa.

8. The brush according to claim 1, wherein the bristles have an average length in the range up to a maximum of 10 mm.

9. The brush according to claim 1, wherein the deflection is in the range from 5% to 15%.

10. The brush according to claim 1, wherein the bristles have a diameter of not more than 0.12 mm.

11. The brush according to claim 1, wherein the bend angle ? is in the range from 12? to 17?.

12. The brush according to claim 1, wherein the bend angle ? is in the range from 7? to 12?.

13. The brush according to claim 1, wherein the bristles are arranged in the form of tufts which are spaced apart from one another.

14. The brush according to claim 1, wherein at least two different bristle lengths are provided.

15. The brush according to claim 1, wherein the adapter for rotationally fixed coupling to the sonic toothbrush drive has a channel extending parallel to the base portion longitudinal axis configured to receive in a form-fit manner a pin of the sonic toothbrush drive.

16. The brush according to claim 1, wherein the elongate base body comprises a load-bearing material having a Young's modulus of not more than 6000 MPa and not less than 2000 MPa.

17. A sonic toothbrush comprising: the brush according to claim 1, and a hand apparatus including the sonic toothbrush drive, wherein the brush is detachably attachable to the sonic toothbrush drive, the sonic toothbrush drive of the hand apparatus is configured to drive the brush in a pivotal oscillating manner about the base portion longitudinal axis, and the sonic toothbrush drive has an operating frequency in the range from 150 to 400 Hz.

18. The sonic toothbrush Set according to claim 17, wherein the sonic toothbrush drive is configured to generate a pivotal oscillation having an angular amplitude of max. 3?.

19. The sonic toothbrush according to claim 18, wherein the adapter of the elongate base portion has a channel and the sonic toothbrush drive includes a pin that is insertable in a form-fit manner into the channel in order to create a detachably fixed connection with respect to the base portion longitudinal axis, so that the brush as a whole is drivable in the pivotal oscillating manner about the base portion longitudinal axis.

20. The brush according to claim 2, wherein: the Young's modulus of the bristles is in the range from 1000 MPa to 3500 MPa, the deflection is in the range from 7% to 13%, the bristles have a diameter of 0.08-0.12 mm, the angle ? is in the range from 7? to 12?, and the bristles have an average length of at least 5 mm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0058] The drawings used to illustrate the embodiments show:

[0059] FIG. 1 a schematic representation of a plan view of a brush;

[0060] FIG. 2 a schematic representation of a side view of the brush;

[0061] FIG. 3 a schematic representation of a rear view of the brush;

[0062] FIG. 4 a schematic representation of a plan view of a sonic toothbrush comprising the brush;

[0063] FIGS. 5a, b a schematic side view and a plan view of a sonic toothbrush;

[0064] FIG. 6 a schematic representation of a side view of a sonic toothbrush with exactly one tuft;

[0065] FIG. 7 a schematic representation of the Figure 8 movement according to the present disclosure;

[0066] FIG. 8 a schematic representation of the angular amplitude of the longitudinal axis oscillation;

[0067] FIG. 9 an embodiment with an oval brush head;

[0068] FIG. 10 an embodiment of a single-tufted brush with a bristle field on the back side; and

[0069] FIG. 11 an embodiment of a single-tufted brush with a bristle field on the front side.

[0070] In principle, identical parts are marked with the same reference symbols in the figures.

DETAILED DESCRIPTION

[0071] FIG. 1 shows a schematic representation of a plan view of a brush 10. The brush 10 comprises a frustoconical base portion 11, a rod-shaped neck portion 12 which adjoins the frustoconical base portion 11, and a plate-shaped head portion 13 which adjoins the neck portion 12. The three parts form the load-bearing base body of the brush.

[0072] The frustoconical base portion 11 comprises a drive adapter. In the present embodiment, this is in essence formed by a channel-shaped receptacle 14, in which a pin of the hand apparatus of the sonic toothbrush is insertable and latchable (see FIG. 4 below). The brush 10 comprises a base portion longitudinal axis 20, which is aligned coaxially with respect to the holder 14 or coaxially with respect to the pin when the sonic toothbrush is in operation. This longitudinal axis defines the x-axis of the x-y-z coordinate system used herein. In other words, the drive adapter defines the geometric base portion longitudinal axis (x) of the brush.

[0073] In FIG. 1 the bristle field 17 of the head portion 13 is also evident, which in the present embodiment comprises multiple (e.g. 20-40) tufts, each with a plurality (e.g. 100-200) of bristles.

[0074] According to a preferred embodiment, the head portion 13 is teardrop-shaped in the front view. This means its shape widens successively-starting at the transition to the neck portion-almost to the upper end of the head portion, where it ends in a rounded end contour. With this shape, the center of gravity of the head portion 13 is (for a given length of the bristle field in the x-direction) closer to the terminal end of the brush. This can increase the eccentric effect at the specified operating frequency and thus also the Figure 8 movement.

[0075] The main surface of the plate-shaped head portion 13 extends in essence transversely along the x-axis in the y-direction.

[0076] Furthermore, a Figure 8 lying (extending) in the y-direction is shown on the bristle field 17 and denoted with the reference sign 23 in FIG. 1. The Figure 8 illustrates the movement which is carried out during operation due to the selected material property (Young's modulus), the angle between the geometric base portion longitudinal axis 20 and the geometric head portion orientation axis (see further below) and the bend position in the plane.

[0077] In addition to the Figure 8, the head portion 13 of the brush 10 also carries out (undergoes) a small nodding movement-this movement is directed, in essence, at right angles to the Figure 8; i.e. the movement is in essence in (along) the z direction. In a preferred embodiment, the bristles are thus moved in three dimensions (x, y, z) during operation.

[0078] FIG. 2 shows a schematic representation of a side view of the brush 10. In addition to the geometric base portion longitudinal axis 20, the geometric head portion orientation axis 21 can also be seen in FIG. 2. In the illustration according to FIG. 1, the base portion longitudinal axis 20 and the head portion orientation axis 21 are one behind the other. The head portion orientation axis 21 is in essence the longitudinal axis of the head portion. The two axes intersect in (at) the geometric bend position 22. In the present embodiment, the geometric base portion longitudinal axis 20 and the geometric head portion orientation axis 21 enclose (form) an angle ? (gamma) of 10? as shown in FIG. 2. The geometric bend position 22 is spaced by a distance K from the end surface of the base portion 11; the distance K is 50% of the total length L of the brush 10. In this combination of the angle with respect to the bend position 22, a brush 10 is created with which a particularly effective and gum-friendly cleaning of the teeth is possible.

[0079] As can be seen by viewing FIGS. 1 and 2 together, in the present embodiment the head portion 13 is plate-shaped and the neck portion 12 is rod-shaped. In the projection of the base body onto the x-z plane, the head portion 13 and the neck portion 12 have the same transverse dimension (i.e. the same thickness). In the projection onto the x-y plane (front view according to FIG. 1), the head portion 13 is about three times as wide (y-direction) as the neck portion 12. The length (x-direction) of the head portion is about one third greater than the width (y-direction). For example, the neck portion 11 is one third as wide and 1.5 times as long as the head portion 13.

[0080] The neck portion 12 is tapered (narrowed) in relation to the head portion 13 and the base portion 11. In the present example, the neck portion 12 is less wide than the head portion 13 in at least one of the side views (viewed here in the z-direction according to FIG. 1).

[0081] In the present example, the base body of the brush 10 is composed, as the load-bearing material, of a glass fiber-reinforced polypropylene, namely Borealis GB311U having a Young's modulus of approximately 3500 MPA (Tensile Strength at yield =97 MPa; Elongation at Yield=2.8%; Young's modulus=Tensile Strength at Yield/Elongation at Yield).

[0082] The deflection is determined by the ratio of distance A to length L of the brush. The distance A corresponds to the distance from the front center of the head portion (which in this case corresponds to the center of the bristle field 17) to the base portion longitudinal axis 20 (see FIG. 2). In this example, the deflection is 14%.

[0083] The bristles are arranged here in multiple tufts and project perpendicularly away from the main surface of the plate-shaped head portion. In the present embodiment, they are perpendicular to the y-direction and run (extend) in the x-z plane. In the present embodiment, the bristles are attached to the front side of the head portion (or the front side 27 of the brush), that is, they point slightly downwards towards the adapter surface (y-z plane) of the base portion. The longitudinal axis of the bristles encloses (forms) an angle with the base portion longitudinal axis 20 that is less than 90?: namely 90? minus the bend angle ?.

[0084] FIG. 3 shows a schematic representation of a rear view of the brush 10 according to FIGS. 1 and 2. As can be seen from FIGS. 1-3, the base body has a different material on the rear side 26, which is soft and provides protection (protective coating, protective sheath) when the brush rear side comes into contact with the teeth. This material is non-load-bearing and can therefore have a Young's modulus outside the Young's modulus range of 2000-6000 MPa. The load-bearing material on the front side 27 is evident and it makes up an essential (substantial) part of the cross-section of the base body.

[0085] FIG. 4 shows a schematic representation of a plan view (z-direction) of a sonic toothbrush comprising the brush 10 and a hand apparatus 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 hand apparatus 16 rotates (pivots, oscillates) 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 (center) position) about the longitudinal axis of the pin 15 (which corresponds to the longitudinal axis of the hand apparatus 16). The brush 10 thus rotates (pivots, oscillates) back and forth about the base portion longitudinal axis 20 (x-axis).

[0086] FIG. 5a shows a schematic representation of a side view of a sonic toothbrush. The sonic toothbrush comprises a hand apparatus 16 and a brush 10. The drive of the hand apparatus 16 is designed as a piezoelectric drive 19, which generates an oscillation of the brush 10 about the x-axis 20 (longitudinal axis of the hand apparatus). The brush 10 thus carries out (undergoes) a rotational (pivotal) oscillation about the x-axis 20 relative to the handle (hand apparatus 16) during operation. Due to the above-described deflection of the head portion 13, an unbalance is created which enhances a movement component in the Y-direction 24 and/or in the Z-direction 25 (see below, FIG. 5b). This effect is controlled (determined) by the suitably angled bend in the brush neck and the suitably selected Young's modulus and can be adjusted by further geometric design features of the brush (such as bend angle position, deflection, mass distribution and other features according to the particular embodiments of the present disclosure).

[0087] FIG. 5b shows a schematic plan view of the personal care appliance (sonic toothbrush) according to FIG. 5a. The Z-direction 25 can be seen in this illustration. It runs, in essence, in the direction of the bristles. As can be seen from FIG. 5b, the hand apparatus is significantly larger than the brush. Only in this way can it generate a longitudinal axis oscillation (instead of an undefined or undirected vibration movement), as is the case with known sonic toothbrushes.

[0088] FIG. 6 shows an embodiment of the sonic toothbrush which comprises exactly one tuft 18. The tuft 18 is arranged on the rear side with respect to the head portion 13. The head portion 13 is thus inclined quasi rearward.

[0089] FIG. 7 shows a schematic representation of the Figure 8 movement according to embodiments of the present disclosure. In the present case, the Figure 8 movement has the shape of the number 8 flattened on one side, wherein an axis of symmetry (X axis) runs through (intersects) the center 27 of the number 8. The two loops (eyes) 28a, 28b of the 8 extend primarily in the y-direction. However, the invention is not limited to exactly this form of Figure 8 movement; the exact form of the movement ultimately depends on the parameters of the brush head and the oscillation generated by the motor of the hand apparatus.

[0090] FIG. 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 portion 13 (shown without bristles) pivots about the x-axis by the angle ? (alpha). (The bristles extend upwards in the z-direction in FIG. 8.) The main component of the pivot movement (and thus the bristle wiping movement) is in the y-direction. The angle ? (alpha) between the rest position (drive switched off) and the maximum deflection from the rest position is preferably a maximum of 3?, preferably 2?. The deflection from maximum left to maximum right is therefore 6? or 4?.

[0091] FIG. 9 shows a brush 10 with a plate-shaped oval head portion 13. The longitudinal axis of the oval shape runs (extends) in essence in the x-direction and the transverse axis runs (extends) in the y-direction. The center of the head portion 13 is further away from the upper (terminal) end of the brush 10 than in the drop-shaped head portion shown in FIG. 1.

[0092] FIG. 10 shows a brush with a bend angle ? (gamma) of 14? and a distance K from the geometric bend position 22 to the end surface 29 of the base portion 11 of 75% with reference to the length L of the brush 10.

[0093] The base portion 11 tapers from the end surface 29 to the transition into the neck portion 12. The base portion 11 can be, for example, frustoconical or truncated pyramid-shaped, wherein it has, for example, a concave profile in longitudinal section. Thus, the center of gravity of the base portion 11 is closer to the end surface 29 than in a comparable base portion having straight profile lines.

[0094] In the embodiment shown in FIG. 10, the neck portion 12 occupies approximately half the length (L) of the brush 10. As FIG. 10 illustrates, the neck portion 12 does not necessarily have to have a constant cross-section over its entire length. It can certainly have a varying contour.

[0095] The head portion 13 is formed by the extension of the neck portion 12. In the present example, the head portion 13 has in essence the same transverse dimensions (viewed in a section perpendicular to the head portion orientation axis 21) as the neck portion 12. The bristle field 17 is positioned on the side of the head portion 13. The bristles therefore protrude perpendicular with respect to the head portion orientation axis 21.

[0096] FIG. 11 shows an embodiment in which the base portion 11 is in essence formed by a pin 30 that serves as a drive adapter. The neck portion 12 is rod-shaped and occupies, for example, 90% of the length of the brush. The head portion 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 hand apparatus (16) in the x-direction for rotationally fixed coupling to a sonic tooth brush drive (19) with longitudinal axis oscillation, wherein the drive adapter defines the geometric base portion longitudinal axis (x) of the brush.

[0097] A brush according to FIG. 11, for example, is made of a material having a Young's modulus of approx. 4600 MPa. 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) is given as an example of such a material.

[0098] In further embodiments not shown, instead of the bristle field 17 the brush 10 comprises an interdental brush for cleaning interdental spaces.

[0099] Additional embodiments of the present teachings will now be explained with reference to specific examples of suitable parameters. Here, the length LB of the bristles is measured from their exit from the front of the head portion to their tip as shown in FIG. 2. In Examples 1 to 6, the bristles are arranged in a plurality of slightly spaced-apart tufts.

[0100] Example 1: The brush has a bend angle ?=14? and a deflection A with reference to the length L of the brush of 10%. The value ?.sub.k of the bristles is around 9.7 MPa. All bristles are made of the same material and have the same geometric dimensions. The Young's modulus of the bristles is 2000 MPa. The length LB of the bristles is 6 mm. The bristles are circular in cross-section and have a diameter of 0.15 mm. This brush is particularly suitable for longitudinal axis oscillation at a frequency of no more than 200 Hz. The brush can be designed, for example, as shown in FIG. 10 or 11.

[0101] Example 2: The brush has a bend angle ?=12? and a deflection A with reference to the length L of the brush of 11%. The value ?.sub.k of the bristles is around 4.5 MPa. All bristles are made of the same material and have the same geometric dimensions. The Young's modulus of the bristles is 4000 MPa. The length LB of the bristles is 10 mm. The bristles are circular in cross-section and have a diameter of 0.12 mm. This brush is particularly suitable for longitudinal axis oscillation at a frequency of 150-300 Hz.

[0102] Example 3: The brush has a bend angle ?=10? and a deflection A with reference to the length L of the brush of 7%. The value ?.sub.k of the bristles is around 2.4 MPa. All bristles are made of the same material and have the same geometric dimensions. The Young's modulus of the bristles is 4500 MPa. The length LB of the bristles is 12 mm. The bristles are circular in cross-section and have a diameter of 0.10 mm. This brush is particularly suitable for longitudinal axis oscillation at a frequency of 150-300 Hz.

[0103] Example 4: The brush has a bend angle ?=8? and a deflection A with reference to the length LB of the bristles of 70%. The value ?.sub.k of the bristles is around 1.5 MPa. All bristles are made of the same material and have the same geometric dimensions. The Young's modulus of the bristles is 3500 MPa. The length LB of the bristles is 12 mm. The bristles are circular in cross-section and have a diameter of 0.09 mm. This brush is particularly suitable for longitudinal axis oscillation at a frequency of up to 400 Hz.

[0104] Examples 2 to 4 can be designed, for example, like the brush shown in FIGS. 1 to 3.

[0105] Example 5: The brush has a bend angle ?=10? and a deflection A with reference to the length L of the brush of 10%. The value ?.sub.k of the bristles is around 0.52 MPa. All bristles are made of the same material and have the same geometric dimensions. The Young's modulus of the bristles is 1500 MPa. The length LB of the bristles is 12 mm. The bristles are circular in cross-section and have a diameter of 0.08 mm. This brush is particularly suitable for longitudinal axis oscillation at a frequency of 150-300 Hz.

[0106] Example 6: The brush has a bend angle ?=11? and a deflection A with reference to the length L of the brush of 8%. The value ?.sub.k of the bristles is around 2.3 MPa. All bristles are made of the same material and have the same geometric dimensions. The Young's modulus of the bristles is 3000 MPa. The length LB of the bristles is 10 mm. The bristles are circular in cross-section and have a diameter of 0.10 mm. This brush is particularly suitable for longitudinal axis oscillation at a frequency of 150-300 Hz.

[0107] Example 7: The brush has a bend angle ?=9? and a deflection A with reference to the length L of the brush of 7%. The brush has two different types of bristles. In an edge area, which is essential for cleaning at the transition between tooth and gum, the bristles have a value ?.sub.k according to Example 2. In an inner area enclosed by the edge area, the Young's modulus is 4000 MPa, the length of the bristles is 9 mm. The bristles are circular in cross-section and have a diameter of 0.12 mm in the entire area. The value ?.sub.k in the inner area is 5.5 MPa. This brush is particularly suitable for longitudinal axis oscillation at a frequency of 150-300 Hz.

[0108] Example 8: The brush has a bend angle ?=16? and a deflection A with reference to the length L of the brush of 17%. The brush has two different types of bristles. The majority of the bristles, which are essential for cleaning at the transition between the tooth and gum, have a value ?.sub.kof 2.6 MPa. The Young's modulus of the bristles mentioned is 4500 MPa, the length LB of the bristles is 7 mm. The bristles are circular in cross-section and have a diameter of 0.06 mm throughout. This brush is particularly suitable for longitudinal axis oscillation at a frequency of 150-300 Hz.

[0109] Examples 5 to 8 can be designed, for example, as shown in each of the brushes of FIGS. 1 to 3 and 9 to 11.

[0110] The bristles need not be circular in cross-section. They can also be slightly oval or non-circular, for example in that the transverse dimension in one direction is 20% larger than the transverse dimension in the direction perpendicular thereto.

[0111] In summary, it is to be ascertained that, according to the present teachings, a brush for a sonic toothbrush drive is created which leads to a particularly advantageous movement of the head portion for effective and efficient cleaning of the teeth.