Toothbrush

Abstract

The invention relates to a toothbrush, comprising a brush head, at least one folded bristle bundle and at least one small anchoring plate made of plastic, the brush head for the at least one bristle bundle having a hole with a longitudinal axis, the small anchoring plate being fixed in the hole for anchoring the respective bristle bundle, the small anchoring plate having a longitudinal axis, according to the invention, the anchor plate is held in two grooves running parallel to the longitudinal axis, which grooves are formed in the bore by means of injection molding, the grooves having a centering section which, when viewed in a direction perpendicular to the longitudinal axis, has a depth which gradually decreases as the distance from the inlet of the bore increases.

Description

Technical Field

[0001] The invention relates to a toothbrush with a brush head made of plastic, with at least one folded bristle bundle and with at least one anchoring plate made of plastic. Background Art

[0002] Usually, when manufacturing toothbrushes, the bristle bundles are fastened in the brush body using metal anchoring plates. In this case, these anchoring plates are wider than the hole diameter, for example 3 / 10 of a millimeter. The anchoring plates are inserted into the bristle bundle holes together with the folded bristle bundles, wherein they are embedded in the brush body material with their opposite outer edges and are thus held.

[0003] In addition, it has been proposed that the bristle bundles are fixed by metal anchors in a brush head made of metal. Holes are drilled in the brush head for the bristle bundles, and small holes arranged opposite to each other on the diameter are arranged in each such hole for introducing the metal anchors (JP2009125084A, KAO CORP).

[0004] The known anchoring techniques are complex to produce and have too low a reliability with regard to the fixing of the bristle bundles. Summary of the invention

[0005] The object of the present invention is to provide a toothbrush belonging to the technical field mentioned at the outset which can be produced more easily and which ensures a more secure anchoring of the bristles.

[0006] The solution to this problem is defined by the features of claim 1 .

[0007] The toothbrush according to the present invention has a brush head made of plastic, at least one folded bristle bundle and at least one anchoring plate made of plastic. The brush head has a hole for the at least one bristle bundle, the hole having a longitudinal axis and a hole cross section having a basic shape for accommodating the folded bristle bundle. In order to anchor the corresponding bristle bundle in the free hole cross section, the anchoring plate is fixed in the hole. Two grooves extending parallel to the longitudinal axis of the hole are retained in the wall of the hole, the grooves (observed perpendicularly to the longitudinal axis) extending beyond the basic shape of the hole cross section and the grooves are constructed in the manner of injection molding technology. The grooves form a U-shaped profile. The anchoring plate is fixed in the two grooves with a U-shaped profile by welding. The groove has a combined section with a centering section and a tapering section immediately following the entrance of the hole, the combined section having a depth and a width when observed in a direction perpendicular to the longitudinal axis, and the depth and width gradually decrease as the distance from the entrance of the hole increases.

[0008] The invention is based on the knowledge that without the combined section according to the invention it is not possible to anchor the plastic anchor sufficiently firmly (i.e. with a sufficiently high extraction force) and sufficiently reliably (i.e. with sufficient consistency in each welding). In particular, tests have shown that when the anchoring plate is not transported symmetrically (e.g. due to a slight production-related offset between the groove and the anchoring plate), it deforms when introduced into the hole and is thus only partially welded, or welding is only achieved at individual locations because the contact between the edge of the anchoring plate and the three wall sides of the U-profile is not sufficient at other locations. In this regard, tests have also shown that significantly higher extraction forces for the bristle bundle are achieved when the anchoring plate is welded to all three sides of the U-shaped groove.

[0009] Tests have also shown that it is important that the U-shaped groove is embedded in the volume material of the brush head. If the wall volume around the groove is too small, the softened plastic material will overflow, which significantly reduces stability.

[0010] Compared to such anchoring plates made of steel, anchoring plates made of plastic have the advantage that easy and environmentally friendly disposal of the toothbrush is possible, since no material separation (metal / plastic) has to take place.

[0011] The longitudinal axis of the hole is preferably perpendicular to the surface of the brush head.Multiple rows of holes parallel to each other can be arranged in the brush head at a small spacing.

[0012] According to a particular embodiment, the opening (viewed transversely to its longitudinal axis) has a geometrically simple basic shape, such as a circle, rectangle or oval.

[0013] The grooves are embedded in the wall of the hole, that is to say they extend beyond the basic shape of the hole cross section and into the volume material of the brush head. When the bristles and the anchoring platelets are joined, the grooves are already present in the hole. These grooves are arranged by injection molding technology, that is to say when the brush head is manufactured by injection molding technology.

[0014] The wall is thus preferably substantially the inner surface of a hollow cylinder or the inner surface of a rectangular or elliptical hollow contour defined by the hole. Thus, the wall is substantially parallel to the longitudinal axis of the hole.

[0015] According to the invention, the groove (viewed perpendicularly to the longitudinal axis of the hole) has a U-shaped cross section. Since the groove is embedded in the wall and not, for example, placed on a rib extending into the (free) hole cross section, the three wall sides of the U profile are surrounded by the volume material of the brush head. Therefore, the material heating and material softening that inevitably occur in the U profile during welding do not lead to a transfer of plastic material. Therefore, the anchoring plate is not only reliably fixed at the end side of the U profile (bottom of the U profile) but also reliably fixed at the edge side of the U profile.

[0016] In order not to weaken the walls between closely adjacent holes in a row, or in order to have sufficient spacing between the grooves of adjacent holes, in a specific embodiment, the basic shape of the hole is designed to be circular or elliptical, and the orientation defined by the grooves of the holes arranged opposite to each other is offset by an angle greater than zero, in particular an angle of 30°-45°, relative to the direction of the row of holes (the hole arrangement direction of directly adjacent holes).

[0017] Since the basic shape is simple (circular, oval, rectangular or similar), that is to say convex (ie without recesses, such as inward ribs or protrusions), and the groove is embedded in the wall, the hole cross section can be optimally adapted to the bristle bundle to be engaged.

[0018] At the entrance of the hole and therefore at the entrance of the groove, the combined section forms, on the one hand, a centering section of the U-shaped profile. This centering section tapers when viewed in the radial direction with respect to the longitudinal axis of the hole in the insertion region or the insertion path for the anchoring plate. On the one hand, the anchoring plate is thereby centered (e.g. with respect to the longitudinal axis of the hole), while on the other hand, the anchoring plate is gradually conveyed during the insertion to the region in which the anchoring plate is finally fixed (hereinafter referred to as the “constant section”), wherein the anchoring plate is welded there to the constant section of the U-profile of the groove substantially over the entire surface.

[0019] According to the invention, the grooves in the combined section also each have a tapering section which, viewed in a direction perpendicular to the longitudinal axis, has a width which decreases with increasing distance from the inlet of the hole. This ensures that the anchoring plate is conveyed symmetrically to the two side walls of the U profile in the constant section.

[0020] Following the combined section, the grooves each have a constant section, which, viewed in a direction perpendicular to the longitudinal axis, has a width and depth that are constant along the longitudinal axis. The width and depth of the U profile in the constant section are adapted to the width and thickness of the anchoring plate. Before the anchoring plate is fixed by friction welding, the width of the U profile in the hole is slightly smaller than the edge of the anchoring plate, and the spacing between the two bottom surfaces of the grooves that are opposite each other is slightly smaller than the width of the anchoring plate.

[0021] According to the invention, the combined section is designed simultaneously as a centering section and a tapering section. This has the advantage that the centering and alignment of the anchoring plate can be achieved over the shortest possible distance.

[0022] According to the invention, the constant section follows the combining section.

[0023] In some embodiments, the depth is reduced in two or more steps. For this purpose, the centering section can also have two or more straight lower sections or curved lower sections, whose angles to the longitudinal axis gradually decrease as the distance from the entrance of the hole increases.

[0024] In some embodiments, the width is reduced in two or more steps. For this purpose, the tapering section can also have two or more straight lower sections or curved lower sections, whose angles to the longitudinal axis gradually decrease as the distance from the inlet of the hole increases.

[0025] In certain embodiments, the width of the groove at the entry into the assembly region can be greater than the thickness of the anchoring plate, in particular at least 5% and at most 100%. Such a widening of the groove makes introduction easier and improves the symmetry of the loads during friction welding in the constant section. The anchoring plate is preferably rectangular. It can be particularly advantageous if there is no bevel on the narrow side.

[0026] The invention also relates to a method for producing a toothbrush with a brush head made of plastic and with at least one bristle bundle anchored in the brush head, the method comprising the following steps:

[0027] a) providing a brush head with a hole for fixing at least one bristle bundle, the brush head having a hole with a longitudinal axis and a hole cross section with a basic shape for accommodating a folded bristle bundle, wherein two grooves extending parallel to the longitudinal axis and extending beyond the basic shape of the hole cross section are constructed in the wall of the hole by injection molding technology, wherein the groove has a combined section with a centering section and a tapering section immediately adjacent to the entrance of the hole, and the combined section has the following depth (T) and width (B) when viewed in a direction perpendicular to the longitudinal axis, and the depth and width gradually decrease as the distance from the entrance of the hole increases;

[0028] b) providing an anchoring plate made of plastic for anchoring the corresponding folded bristle bundle in the hole;

[0029] c) Engaging the anchoring plate with the folded bristle bundles into the hole, wherein the anchoring plate is introduced into the combined section of the groove and fixed in the U profile by means of a friction welding process.

[0030] Preferably, the grooves each have a constant section which, viewed in a direction perpendicular to the longitudinal axis, has a width and a depth which are respectively constant along the longitudinal axis.

[0031] Further advantageous embodiments and feature combinations of the invention emerge from the following detailed description and from the entirety of the patent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] To explain the example:

[0033] Figure 1 a perspective view showing the rows of holes in the brush head;

[0034] Figure 2 A perspective view showing the rows of holes with inserted anchoring platelets;

[0035] Figure 3 A schematic cross-sectional view showing a hole with an anchoring plate capable of introducing a bundle of bristles into the hole, as well as a centering section and a constant section of a groove;

[0036] Figure 4 Show direction Figure 3 A schematic top view of the hole shown in FIG.

[0037] Figure 5 Shown with anchor plate Figure 3 and Figure 4 A schematic cross-sectional view of a hole in which the anchoring plate has folded the bristle bundle and introduced it into the hole;

[0038] Figure 6 Show direction Figure 5 A schematic top view of the hole shown in FIG.

[0039] Figure 7 A schematic cross-sectional view showing a hole with a slot having a tapered section, a centering section, and a constant section; and

[0040] Figure 8 Show direction Figure 7 Schematic top view of the hole shown in . DETAILED DESCRIPTION

[0041] Figure 1 A transparent brush head 1 is shown of an embodiment of a toothbrush according to the invention. This embodiment has a plurality of cylindrical holes 5 arranged in a plurality of rows. The basic shape of the holes in longitudinal section is therefore circular. Folded bristle bundles (not shown) and corresponding plurality of anchoring plates 3 made of plastic are inserted into the holes. The holes are preferably designed as blind holes in a one-piece brush head.

[0042] The brush head 1 also has a hole 5 for each bristle bundle, which has a longitudinal axis L1. In the present example, all holes 5 are oriented identically with their longitudinal axes, i.e. perpendicularly to the upper main surface of the brush head. Anchoring plates 3 are used to anchor the respective bristle bundles and are fixed in the holes 5. The longitudinal axis L1 is here exactly perpendicular to the surface 4 of the brush head.

[0043] According to an advantageous embodiment, the hole 5 itself does not taper or widen, that is to say the cross section of the wall 6 is constant along the longitudinal axis L1 of the hole 5. In other words, the wall is substantially parallel to the longitudinal axis L1.

[0044] Each hole now has two grooves 7 and 8, which are embedded in the wall 6 of the hole 5 by injection molding technology, are arranged opposite each other and are oriented parallel to the longitudinal axis L1 and are designed to accommodate the anchoring plate 3. The grooves extend from the entrance of the hole 5 or from the surface 4 of the brush head to a depth in the lower half of the hole 5.

[0045] In the present embodiment, the groove pairs of the holes are not oriented parallel to the hole arrangement, but are inclined at an angle of about 45° to the direction of the hole arrangement. This has the advantage that the grooves of adjacent holes have a relatively large spacing from one another.

[0046] Figure 2 show Figure 1 , wherein an exemplary anchoring plate 3 is fixed here. The anchoring plate is essentially rectangular. Preferably, there are no bevels at the sides. This allows large-area welding of the anchoring plate in the constant section of the groove.

[0047] When pushed in, the anchoring plate 3 is clamped between the grooves 7 and 8 in such a way that the corresponding dimension of the anchoring plate 3 is higher than the spacing between the bottoms of the grooves 7 and 8, at least in the end position of the anchoring plate shown here. The anchoring plate 3 is welded to the U-profile of the grooves 7 and 8, for example by friction welding or by ultrasonic excitation of at least one of the components involved.

[0048] exist Figure 3 and Figure 4 In the embodiment shown in FIG. 8 , the two grooves 9 and 10 extend continuously to the hole bottom 11 . Figure 4 is a top view toward hole 12, and Figure 3 is a cross section through the hole 12 in the plane S1. In the upper region, the groove has a centering section Z1, in which the groove bottom extends obliquely to the longitudinal axis L2. Immediately following the centering section, the groove has a constant section K1, in which the groove bottom extends parallel to the longitudinal axis L2. Here, for clamping and / or welding, the following situation can be used: the depth T of the grooves 9 and 10 is observed along the longitudinal axis L2 and begins to decrease from the hole 12 into the surface 13 or the entrance of the brush head 14, and therefore when the anchoring platelet 15 is pushed in, the anchoring platelet is symmetrically conveyed therein. In particular, the value of the depth T extends here from the maximum value T2 at the entrance of the hole to the minimum value T1 at the end of the centering section Z1. In other words, the depth T of the groove is the distance value in the first plane S1 / S2, which passes through the longitudinal axis L2 and extends perpendicularly through the two grooves. Correspondingly, the width B1 is the distance value in the second plane extending perpendicularly to the first plane.

[0049] in accordance with Figures 3 to 6Now, it is explained how to anchor the bristle bundle 2 in the hole 12 by the anchoring plate 15. By introducing the anchoring plate 15 into the grooves 9 and 10, the bristle bundle 2 is folded so that after the anchoring is completed, the bristles extend upward from the hole 12. Figure 5 and Figure 6 Here Figure 5 yes Figure 6 1 and 2. It can also be seen how the anchoring platelets 15 are clamped in the grooves.

[0050] Both parts (bristle head 14 and anchoring platelet 15) are made of plastic, in particular of the same material, and the two parts can be welded.

[0051] exist Figures 3 to 6 In this embodiment, another optional aspect can also be seen, which can be used in various embodiments independently of other optional aspects: the width B1 in the combined section of the groove is wider at the edge of the hole than the thickness D of the anchoring plate 15, in particular at least 5% wider (for example at most 10%). Where the combined section meets the constant section, the width of the combined section is as wide as the constant section.

[0052] If you want a more precise and stable assembly, Figure 7 and Figure 8 The embodiment shown in has the groove modified in that a tapering section V is also provided. Figure 7 yes Figure 8 The embodiment shown here is a view of the section S3 marked in FIG. Figure 1 and Figure 2 The embodiment shown in is based on the embodiment shown in . When viewed in the direction S3, the depth decreases gradually. Here, the width B of the grooves 16 and 17 also decreases gradually with increasing distance from the entrance of the hole 20 on the surface 18 of the brush head 19. This additional taper has the effect that the anchoring plate (not shown here) is loaded biaxially centered and symmetrically when it is inserted into the groove and introduced into the constant section in the manner of friction welding technology.

[0053] In addition, according to Figure 7 and Figure 8In the embodiment of , a further optional aspect is shown, which can also be used in various embodiments independently of the other optional aspects: both the centering section Z2 and the tapering section V (only one of the two tapering sections is also possible) are here implemented in two steps, that is to say a first step from the brush head surface 18 downwards tapers the groove at a first angle, and a second step following the first step tapers the groove again, however at a second angle which is smaller than the first angle. Up to the third stage (constant section K2) of the setback (Absetzung) of the grooves 16 and 17 is then parallel to the longitudinal axis L3 as shown, but can also be implemented inclined. In accordance with Figures 3 to 6 In the embodiment of the present invention, the tapering of the groove depth can also be implemented in two steps or in a plurality of steps.

[0054] Although the present invention has been explained according to its (multiple) preferred embodiments, many further modifications and variations may be made without departing from the scope of the present invention. It is therefore provided that the appended patent claims cover modifications and variations included within the actual scope of the present invention.

Claims

1. A toothbrush with a brush head (1, 14, 19) made of plastic, at least one folded bristle bundle (2) and at least one anchoring plate (3, 15) made of plastic, in, The brush head (1, 14, 19) for at least one bristle bundle (2) has a hole (5, 12, 20) with a longitudinal axis (L1, L2, L3) and a hole cross section with a basic shape for accommodating the folded bristle bundle (2), wherein an anchoring plate (3, 15) is fixed in the hole (5, 12, 20) for anchoring the corresponding bristle bundle (2). wherein two grooves (7, 8, 9, 10, 16, 17) extending parallel to the longitudinal axis (L1, L2, L3) and extending beyond the basic shape of the hole cross section are formed in the wall of the hole (5, 12, 20) by injection molding technology, It is characterized in that The anchoring plate (3, 15) is fixed in the two grooves (7, 8, 9, 10, 16, 17) with a U-shaped profile by welding. The groove (7, 8, 9, 10, 16, 17) has a combined section with a centering section and a tapering section (Z1, Z2) immediately following the entrance of the hole, and the combined section has the following depth (T) and width (B) when viewed in a direction (S1, S2, S3) perpendicular to the longitudinal axis (L1, L2, L3), and the depth and width gradually decrease as the distance from the entrance of the hole (5, 12, 20) increases.

2. The toothbrush according to claim 1, wherein: The grooves (7, 8, 9, 10, 16, 17) each have a constant section (K2) which, when viewed in a direction (S1, S2, S3) perpendicular to the longitudinal axis (L1, L2, L3), has a width (B1) and a depth (T1), which are respectively constant along the longitudinal axis (L1, L2, L3).

3. A toothbrush according to any one of the preceding claims, wherein: The depth (T) decreases in two steps.

4. A toothbrush according to any one of the preceding claims, wherein: The width (B) decreases in two steps.

5. A toothbrush according to any one of the preceding claims, wherein: The width (B1) is greater than the thickness (D) of the anchoring platelet (3, 15), in particular at least 5% greater and in particular at most 100% greater.

6. A toothbrush according to any one of the preceding claims, wherein: The anchoring direction formed by the grooves lying opposite one another is at an angle greater than zero relative to the hole arrangement direction of the directly adjacent holes.

7. A method for producing a toothbrush with a brush head (1, 14, 19) made of plastic and with at least one bristle bundle anchored in the brush head, the method comprising the following steps: a) providing a brush head (1, 14, 19) with a hole for fixing at least one of the bristle bundles (2), the brush head (1, 14, 19) having a hole (5, 12, 20) with a longitudinal axis (L1, L2, L3) and a hole cross section with a basic shape for accommodating the folded bristle bundle (2), wherein: Two grooves (7, 8, 9, 10, 16, 17) extending parallel to the longitudinal axis (L1, L2, L3) and extending beyond the basic shape of the hole cross section are formed in the wall of the hole (5, 12, 20) by injection molding technology, wherein the grooves (7, 8, 9, 10, 16, 17) have a combined section with a centering section and a tapering section (Z1, Z2) immediately following the hole inlet, the combined section having a depth (T) and a width (B) when viewed in a direction (S1, S2, S3) perpendicular to the longitudinal axis (L1, L2, L3), the depth and width gradually decreasing with increasing distance from the hole inlet (5, 12, 20); b) providing an anchoring plate made of plastic for anchoring the corresponding folded bristle bundle (2) in the hole (5, 12, 20); c) Engaging the anchoring plate with the folded bristle bundles into the bore, wherein the anchoring plate is introduced into the joining section of the groove and fixed in the U-profile by means of a friction welding process.

8. The method according to claim 7, wherein: The grooves (7, 8, 9, 10, 16, 17) each have a constant section (K2) which, when viewed in a direction (S1, S2, S3) perpendicular to the longitudinal axis (L1, L2, L3), has a width (B1) and a depth (T1), which are respectively constant along the longitudinal axis (L1, L2, L3).

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