DE9111499U1 - toothbrush - Google Patents

Description

BRflun

Braun Aktiengesellschaft

05659/P7]2./kar
14 Aug 1991

toothbrush

The invention is based on a brush suitable for a toothbrush with a handle part and a brush part for cleaning the teeth, in particular the interdental space. The brush consists of a bristle carrier and bristles attached to it, the bristle carrier is designed as a rod-shaped shaft with a first and a second end section and is bristled free in the area of the second end section. The bristles extend radially in the area of the first end section with respect to the shaft and are distributed circumferentially.

Such a toothbrush is already known from the publication DE 90 14 271 Ul. This electrically operated toothbrush has a drive for the brush, which sets it in a rotating movement. The brush rotates around an axis that is arranged perpendicular to the longitudinal axis of the brush handle. The brush itself has either the shape of a roller or a cone, with the cone tip arranged at the first end section. This electric toothbrush is said to be particularly suitable for cleaning teeth when fixed braces are present. However, if this electric toothbrush is used to clean the interdental space of the teeth in particular, there is a risk that the bristle carrier, designed as a rod-shaped shaft, will come into contact with the teeth or gums during the brushing process and cause damage to the tooth surface or injuries to the gums.

Furthermore, from US 4 751 761 A or US 4 387 479 A hand-operated toothbrushes for cleaning, in particular the interdental space, are known in which the bristle carrier, designed as a rod-shaped shaft, consists of a twisted double wire arrangement and the bristles are arranged between the wires of the double

BRHun

Braun Aktiengesellschaft

- 2 - 05659/*>Tl2./fca1

14 Aug 1991

wire arrangement. These brushes for hand-operated toothbrushes also have either a roller shape or are conical, with the tip of the cone being assigned to the first end section of the shaft. Even with these brushes, in which the bristle carrier consists of a metal wire, there is a risk in practical use that the tip on the first section of the bristle carrier will cause injuries to the gums or damage to the tooth surface. In addition, these hand-operated interdental toothbrushes are not particularly suitable for cleaning small interdental spaces. This is because, according to the recommendations of the manufacturers of such well-known interdental brushes, the user should insert the shaft of the brush into the interdental space and move it back and forth. Since the shaft itself already has a diameter in the range between 0.2 mm - 0.4 mm, the interdental brush cannot be used in narrow interdental spaces. But the bristles of these brushes can hardly penetrate into the interdental spaces, since the first end section, which is best suited for cleaning in terms of handling, has practically no bristles or only very short ones (conical brush). With cylindrical brushes, the bristles can also only penetrate into the interdental spaces to a small extent, since the neighboring bristles rest on the outer or inner surfaces of the teeth.

The object of the invention is to create a brush for a toothbrush which leads to particularly good cleaning results, in particular when cleaning interdental spaces, whereby injury to the gums or damage to the tooth surfaces by the bristle carrier is largely avoided.

This object is essentially achieved in that, in a brush with the features mentioned at the beginning, the length of the bristles decreases from the first end section of the shaft towards the second end section of the shaft.

BRflun

Braun Aktiengesellschaft

- 3 - 05659/PTl 2/5cai

14 Aug 1991

A brush with these features offers the following advantages. If the bristle holder of the brush is guided parallel to the outer or inner surfaces of the teeth - in contrast to the conventional, recommended brushing movement - the longer bristles provided at the first end section can reach into the interdental spaces between the teeth extremely effectively and clean these areas effectively. The area of the tooth margins is also well covered and effectively cleaned by the longer bristles at the first end section. When handling the brush in this way, there is no risk of the bristle holder coming into contact with the teeth or gums, as the shorter bristles rest on the teeth while the longer bristles penetrate into the spaces between the teeth. However, if the bristle holder of the brush is inserted into an interdental space between two teeth in the conventional way, the longer bristles arranged at the first end section, which are supported on the adjacent side walls of the two teeth, ensure that direct contact between the teeth or gums and the bristle holder cannot occur. This means that the risk of injury or damage is practically eliminated even when handling the brush in this way.

In one embodiment of the invention, the length of the bristles decreases linearly with increasing distance from the first end section. The brush takes on the shape of a circular cone or a truncated cone, with the tip of the cone or the small diameter of the truncated cone pointing towards the base of the bristle carrier, i.e. in the direction of the second end section of the bristle carrier. Due to the large diameter of the brush in the area of the first end section, the gums or teeth are well protected from contact by the bristle carrier.

The brush is quite large with a diameter that decreases from values in the range of 10 +/- 2 mm to values in the range of 5 +/- 2 mm.

BRflun

Braun Aktiengesellschaft

- 4 - 05659/PT12/kai

14 Aug 1991

large compared to conventional, hand-operated and motor-operated interdental brushes. Nevertheless, due to the modified shape and handling of the brush - guiding the bristle carrier parallel to the outer or inner surfaces of the teeth - a very good cleaning result is achieved.

In a further embodiment of the invention, the bristle thickness in the first end section of the brush decreases from values in the range of 6 +/- 1 mil (1 mil corresponds to 0.0254 mm) towards the second end section to values in the range of 4 +/- 1 mil. By using harder bristles in the area of the first end section, the cleaning effect of the brush is further improved.

It has proven to be advantageous that the length of the bristles decreases in stages with increasing distance from the first end section, in particular in a single stage. This measure proposes a brush which, starting from the first end section, forms a roller of large diameter, which is followed by a roller of smaller diameter. The step, starting from the first end section, is preferably provided after about a third of the total length of the bristle section of the brush. This results in the advantage that the brush is supported on an inner or outer surface of the tooth with the roller of smaller diameter during use, while the roller of larger diameter penetrates into the interdental space to clean it.

An advantageous dimensioning of the brush results from the diameter of the larger roller assuming a value in the range of 12 +/- 2 mm and the diameter of the smaller roller assuming a value in the range of 6 +/- 2 mm.

In an advantageous embodiment of the invention, the bristle thickness of the brush in the first end section has values in the range

BRflun

Braun Aktiengesellschaft

- 5 - i

14 Aug 1991

of 6 +/- 1 mil, while the bristle thickness decreases to values in the range of 4 +/- 1 mil.

According to a further feature of the invention, the axial length of the first section of the shaft assumes values in the range of 12 +/- 3 mm and that of the second section of the shaft assumes values in the range of 9 +/- 3 mm. On the one hand, this measure ensures that the bristle-covered section of the shaft is long enough to achieve a good cleaning effect, and on the other hand, the unbristle-covered section of the shaft is long enough to be attached to a brush holder by injection molding, inserting or other means of securing it.

In a particularly advantageous embodiment of the invention, in which the shaft consists of a twisted double wire arrangement and the bristles are fixed between the wires of the double wire arrangement, the brush is set in an oscillating rotary movement relative to the shaft by means of a motor drive, with the oscillation angle preferably assuming values in the range of +/- 35° +/- 5°. This measure avoids the following disturbing, and in some cases even dangerous, effect that occurs with toothbrushes in which the brush is driven in rotation in one direction. If such toothbrushes are equipped with interdental brushes whose shaft consists of a twisted double wire arrangement, the twisted shaft can act as a thread, so to speak, which, when the brush is rotated in the appropriate direction, automatically rotates into the interdental space between two teeth until it stops on the brush holder, without the user being able to avoid this. Major damage to the tooth surfaces or gums of the user cannot be ruled out. The solution here is to use a brush that can be set in an oscillating rotational movement relative to the shaft. The oscillation angle preferably takes values in the range of +/- 35° +/- 5°.

BRflun

Braun Aktiengesellschaft

- 6 - 056§9/PT12/kaT

14 Aug 1991

Due to the small angle of rotation, the tendency of the brush to screw itself into the interdental space due to the twisted double wire arrangement of the shaft is reduced to practically zero, especially since any slight screwing in during one oscillation period of the oscillating rotary movement is reversed by the next oscillation period. Practical tests have shown that this oscillating drive of the brush actually makes it easier for the user to intentionally penetrate the interdental space.

According to a further feature of the invention, the shaft of the brush is arranged essentially perpendicular to a common longitudinal axis of the handle part and the brush part. This angled position of the brush with respect to the longitudinal axis results in extremely easy handling of the toothbrush, since the user can easily guide the brush parallel to the outer or inner surfaces of the teeth, as well as perpendicular to them. It goes without saying that the brush according to the invention can advantageously be used with both manual and electrically operated toothbrushes.

Further features, advantages and possible applications of the invention are apparent from the following descriptions of the embodiments, which are shown in more detail in the drawing. All described and/or illustrated features form the subject matter of the invention, either individually or in any combination, regardless of their summary in the claims and their reference back to them. They show:

Fig. 1 is a schematic representation of an electrical

schen toothbrush in side view,

BRflun

Braun Aktiengesellschaft

- 7 - 05659/PT12/fcai

14 Aug 19'Jl

Fig. 2a, b a first embodiment of a brush,

detached from or attached to the brush holder,

Fig. 3a, b a second embodiment of a brush,

detached from or attached to the brush holder,

Fig. 4, 5, 6a, b different positioning of the brushes in relation to the teeth to explain the possible brushing movements.

In the figures, reference number 20 designates an electric toothbrush. The toothbrush 20 consists of a handle part and a brush part 24 that can be coupled to it. The handle part 22 accommodates an accumulator 26 or a battery. Furthermore, an electric motor 28 and a reversing device 30 for converting the continuous rotational movement of the electric motor into an alternating rotary movement are arranged in the handle part. A switch 32 for activating the toothbrush 20 is attached to the outside of the handle part 22. The brush part 24 has a hollow support tube 36 that accommodates a shaft 34. The support tube 36 and the shaft can be connected to the handle part 22 via a coupling 40 (not shown in detail). A brush 41 is arranged on the end of the brush part 24 facing away from the handle part 22 and is fixed to a brush holder 44. The brush 41 has a rod-shaped shaft 38 as a bristle carrier, from which bristles 45 extend in a radial direction and distributed around the circumference. This circumferential distribution does not have to be uniform. The bristles can of course also have distribution centers with regard to the circumference, so that the bristles are alternately denser or less dense. The brush holder 44 is set in an alternating rotary motion by the shaft 34 via a bevel gear 42. For this purpose, a bevel gear 46 arranged at the base of the brush holder 44 interacts with a bevel gear segment 48 provided at the head end of the shaft 34.

BRHUn

Braun Aktiengesellschaft

- 8 - O56£9/PT12/Quay

14. Ai;g. 1991

The axis of rotation of the brush holder 44 or the brush 41 forms a substantially right angle with the axis of rotation of the shaft 34 or a common longitudinal axis of the handle part 12 and the brush part 24. However, this angle can also deviate from the right angle by +/- 60° without limiting the invention. The angle of rotation range covered by the brush holder 44 or the brush 41 can assume values in the range between +/- 20° and +/- 100°. However, a value in the range of approximately +/-35° +/- 5° is preferred. This toothbrush of Fig. 1 is described in detail in the international patent application with the publication number WO 91/07116 (code number 05537) of the applicant, the content of which is incorporated by express reference into the disclosure content of the present application.

The brush 41 consists of a particularly rod-shaped shaft 38, which can be formed, for example, by a twisted double wire arrangement 56 (Fig. 2b, 3b). Before twisting the double wire arrangement 56, the bristles 45 are introduced into the space between the wires of the double wire arrangement 56. To secure the bristles 45 to the bristle carrier designed as a shaft 38, the double wire arrangement 56 is then twisted so that the individual bristles 45 are arranged spirally with respect to the shaft 38. The bristles 45 are preferably arranged radially with respect to the shaft 38 and extend in a circumferentially distributed manner, preferably evenly distributed. The shaft 38 can also be designed as a one-piece plastic part in which the bristles 45 are secured by overmolding or similar known fastening techniques.

The shaft 38 has a first end section 50 and a second end section 52. Starting from the first end section 50, the shaft 38 is provided with bristles 45 over a larger area, while in the area of the second end section 52 of the shaft no bristles are fixed to it. The unbridled

BRflUn

Braun Aktiengesellschaft

- 9 - 05639/PT12/kai

14 Aug 1591

Section of the shaft 38 in the area of the second end section 52 serves to secure the brush 41 to the brush holder 44. This securing can be achieved, for example, by molding the unbridled shaft 38 with plastic material, by clamping or similar fastening measures. Starting from the first end section 50, the shaft 38 is equipped with bristles 45 of a predetermined length, with the length of the bristles decreasing in the direction of the second end section 52 of the shaft 38.

According to the embodiment of Fig. 2, the length of the bristles decreases linearly in the direction of the second end section 52, so that the brush 41 has the shape of a circular cone or truncated circular cone, with the largest radius of the circular cone being provided in the area of the first end section 50. The largest diameter of the brush 41 preferably assumes values in the range of 10 +/- 2 mm, with this diameter decreasing to minimum diameters in the range of 5 +/- 2 mm for a truncated cone-shaped brush 41.

In the area of the first end section 50, bristles 45 of a greater bristle thickness are preferably provided than in the remaining area of the brush 41. It has thus proven advantageous that the bristle thickness in the area of the largest diameter of the brush 41 has values of 6 +/- mil (1 mil corresponds to 0.0254 mm). The remaining area of the brush 41 is formed by bristles 45 of a bristle thickness in the range of 4 +/- 1 mil.

In a further embodiment of the brush 41 (Fig. 3), the length of the bristles 45 decreases in steps with increasing distance from the first end section 50 of the shaft 38. In the exemplary embodiment, a single step 54 is provided, which is arranged at approximately one third of the total length of the bristle section of the brush 41, starting from the first end section 50. The shape of this brush 41 is similar to that of two brushes arranged one behind the other.

BRflun

Braun Aktiengesellschaft

- 10 - 05659/&Rgr;&Tgr;12/^

14 Aug 1991

net rollers, the first roller having a larger diameter than the second roller. Preferably, the diameter of the larger roller is in the range of 12 +/- 2 mm and the diameter of the smaller roller is in the range of 6 +/- 2 mm. Advantageously, the bristles of the larger roller have a bristle thickness in the range of 6 +/- 1 mil and the bristles of the smaller roller have values in the range of 4 +/- 1 mil.

While Figures 2a, 3a show an unattached brush 41, Figures 2b, 3b show the brush 41 fixed to the brush holder 44. It can be seen that the shaft 38, which is designed in particular as a double wire arrangement 56, forms approximately a right angle to a central axis of the brush part 24. The motor drive of the toothbrush 20 causes the brush 41 to oscillate around the bristle holder, with the alternating angle of rotation assuming values in the range of preferably +/- 35°.

The possible positioning of the brush 41 in relation to the teeth 58 for cleaning in particular the interdental spaces 60 or tooth margins 64 is explained in more detail in Figures 4, 5 and 6. To clean the tooth margins 64 or the entry areas of the interdental spaces 60, the shaft 38 of the brush 41, which can be conical or stepped, is guided in the Z-Y plane of the coordinate system 62, in particular in the Z direction along the outer or inner surfaces of the teeth. The coordinate system 62 is to be understood as a system related to individual teeth, so that the outer or inner surfaces of each tooth 58 lie in the Z-Y plane and the interdental spaces 60 lie in the Z-X plane. Cleaning of the interdental spaces 60 can be carried out particularly effectively when using the stepped brush 41 if the shaft 38 is guided essentially along the Y-direction of the coordinate system 62. The stepped brush 41 has the advantage that the roller with the large diameter can be moved into the interdental spaces 60 during this handling.

Braun Aktiengesellschaft

05659/PT12/kai
14 Aug 1991

dental spaces 60, whereby the roller with the smaller diameter is supported on the outer or inner surface of the tooth.

If the brush 41 is moved in the direction of the x-axis into an interdental space 60 (Fig. 6a, b), the long bristles on the first end section 50 of the shaft 38 protect the teeth 58 and the gums from contact with the shaft 38 (Fig. 6a). If the interdental spaces are so large, for example due to illness or the user's disposition, that the brush 41 can be inserted completely into the interdental space 60 (Fig. 6b), the teeth 58 and the gums are also protected from contact with the shaft 38 by the bristles arranged in the middle part of the brush 41.

The oscillating drive of the brush 41 ensures a high cleaning effect of the brushes 41, whereby the brushes 41 largely avoid damage to the teeth or injury to the gums due to their special design. Furthermore, the oscillating movement of the brush in an angular range of approximately +/- 35° +/- 5° ensures that when using a shaft 38 consisting of a twisted double wire arrangement 56, the brush cannot screw itself into an interdental space 60, as could be the case with a rotating drive of the brushes 41. The essentially vertical arrangement of the shaft 31 of the brush 41 in relation to a longitudinal axis of the brush part 24 or the handle part 22 allows a versatile, hand-friendly positioning of the brush 41 in relation to the teeth 58 or interdental spaces 60 to be cleaned.

Claims (10)

BRflUn Braun Aktiengesellschaft - 12 - 05659/PTl2/ka- 14. Aug. &Idigr;991 claims 1. A brush (41) suitable for a toothbrush (20) with a handle part (22) and a brush part (24) for cleaning the teeth (58), in particular the interdental spaces (60), the brush (41) consisting of a bristle carrier and bristles (45) attached thereto, the bristle carrier being designed as a rod-shaped shaft (38) with a first and second end section (50, 52) and being bristle-free in the region of the second end section (52), the bristles (45) extending in the region of the first end section (50) in a radially and circumferentially distributed manner with respect to the shaft (38), characterized in _that the length of the bristles (45) decreases starting from the first end section (50) of the shaft (38) in the direction of the second end section (52) of the shaft (38). 2. Brush according to claim 1, characterized in that the length of the bristles (45) decreases linearly with axial distance from the first end portion (50). 3. Brush according to claim 1, characterized in that the diameter of the brush (41) decreases from a value in the range 10 +/- 2 mm to a value in the range 5 +/- 2 mm. 4. Brush according to claim 1, characterized in that the bristle thickness in the first end section (50) of the brush (49) decreases from values in the range 6 +/- 1 mil (1 mil corresponds to 0.0254 mm) towards the second end section (52) to values in the range 4 +/- 1 mil. 5. Brush according to claim 1, characterized in that the length of the bristles (45) increases with increasing distance from the first end portion (50) in a step-like manner, in particular in a single BRflun Braun Aktiengesellschaft - 13 - 05659/PT12/ka· 14. Acg. &Idigr;991 step (54), wherein the step (54) starting from the first end section (50) is preferably provided after approximately one third of the total length of the bristle section of the brush (41). 6. Brush according to claim 5, characterized in that the diameter of the brush (41) has a value in the range 12 +/- 2 mm to a value in the range of 6 +/- 2 mm. 7. Brush according to claim 5, characterized in that the bristle thickness in the first end section (52) of the brush (41) decreases from values in the range of 6 +/- 1 mil (1 mil corresponds to 0.0254 mm) towards the second end section (52) to values in the range of 4 +/- 1 mil. 8. Brush according to claim 1, characterized in that the axial length of the bristle-covered region of the shaft (38) has values in the range of 12 +/- 3 mm and the length of the unbristle-covered portion of the shaft (38) has values in the range of 9 +/- 3 mm. 9. Brush according to claim 1, characterized in that the shaft (38) consists of a twisted double wire arrangement (56), the bristles (45) are fixed between the wires of the double wire arrangement (56) and the brush (41) can be set into an oscillating rotary movement relative to the shaft (38) by means of a motor drive, the oscillation angle preferably assuming values in the range of +/- 35° +/- 5°. 10. Brush according to claim 9, characterized in that the shaft (38) of the brush (41) is arranged substantially perpendicular to a longitudinal axis of the brush part (24) and optionally of the handle part (22).