toothbrush

Abstract

The present invention relates to a toothbrush comprising a brush head, at least one folded bristle bundle and at least one plastic anchor plate piece, the brush head having a hole with a longitudinal axis for at least one bristle bundle, an anchor plate piece being fixed in the hole for fixing each bristle bundle, the anchor plate piece being held in two grooves extending parallel to the longitudinal axis, the grooves being formed in the hole on the basis of injection molding technology, the groove having a centering portion, the centering portion having a depth, viewed in a direction perpendicular to the longitudinal axis, which gradually decreases as the distance from the entrance of the hole increases.

Description

Technical Field

[0001] The present invention relates to a toothbrush comprising a plastic brush head, at least one folded tuft of bristles, and at least one plastic anchor plate piece.

Background Art

[0002] In a conventionally customary form, when manufacturing a toothbrush, the tuft of bristles is attached to the brush head by a metal anchor plate piece. In this case, these anchor plate pieces are, for example, 3 / 10 mm wider than the hole diameter. The anchor plate pieces are pushed into the holes for the tufts of bristles together with the folded tuft of bristles. At this time, the anchor plate pieces are embedded in the brush body material with outer edges located on opposite sides of each other and are thereby held.

[0003] Furthermore, in the case of a metal brush head, it has already been proposed to fix the tuft of bristles by a metal anchor. The brush head is perforated with holes for the tufts of bristles, and in each hole, small holes for introducing metal anchors located diametrically opposite to each other are formed (Japanese Patent Application Laid-Open No. 2009-125084, Kao Corporation).

[0004] In known fixing techniques, it is labor-intensive in production and the certainty of fixing the tuft of bristles is low.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] An object of the present invention is to provide a toothbrush belonging to the technical field described at the beginning, which can be easily manufactured and guarantees reliable fixing of the bristles.

Means for Solving the Problems

[0007] The means for solving the problem is defined by the features of claim 1.

[0008] The toothbrush according to the present invention comprises a plastic brush head, at least one folded bristle bundle, and at least one plastic anchor plate piece. The brush head has a hole for at least one bristle bundle, having a longitudinal axis and a hole cross-section having a basic shape for accommodating the folded bristle bundle. An anchor plate piece is fixed within the hole to fix each bristle bundle within its free cross-section. The wall of the hole holds two grooves extending parallel to the longitudinal axis of the hole, the grooves extending beyond the basic shape of the hole cross-section (viewed perpendicular to the longitudinal axis), and are formed based on injection molding technology. The grooves form a U-shaped molded portion. The anchor plate piece is fixed to both grooves of the U-shaped molded portion by welding. The grooves have a combined portion having a centering and tapered portion following the entrance to the hole, the combined portion having a depth and width that gradually decreases as the distance from the entrance to the hole increases when viewed perpendicular to the longitudinal axis.

[0009] The present invention is based on the recognition that without the combined parts according to the present invention, it is not possible to secure the plastic anchor sufficiently firmly (i.e., with sufficiently high pull-out force) and sufficiently reliably (i.e., with sufficient consistency during each welding). That is, experiments have shown that if the anchor plate piece is not supplied sufficiently symmetrically when introduced into the hole (for example, due to slight manufacturing misalignment between the groove and the anchor plate), it will deform, resulting in only partial welding, or insufficient contact between the edge of the anchor plate piece and the three wall sides of the U-shaped form at other locations, resulting in welding only occurring at individual locations. In this regard, it has also been found that a significant increase in pull-out force against the hair bundle is achieved when the anchor plate piece is welded to all three sides of the U-shaped groove.

[0010] Experiments have also shown that it is important that the U-shaped grooves are machined into the material of the brush head. If the volume of the walls around the grooves is too small, the softened plastic material may escape, which significantly reduces stability.

[0011] Plastic anchor plate pieces have advantages over steel anchor plate pieces, as they do not require material separation (metal / plastic), allowing for simple and environmentally friendly toothbrush disposal.

[0012] Preferably, the longitudinal axis of the holes is perpendicular to the surface of the brush head. The brush head may have multiple rows of holes that are parallel to each other and spaced slightly apart.

[0013] According to one particular embodiment, the hole has a geometrically simple basic shape, such as circular, rectangular, or elliptical (when viewed lateral to its longitudinal axis).

[0014] The grooves are machined into the walls of the holes; that is, the holes extend beyond the basic shape of the cross-section of the holes into the voluminous material of the brush head. The grooves are already present in the holes when the bristles and anchor plate pieces are inserted. The grooves are formed based on injection molding technology, i.e., during the manufacture of the brush head using injection molding technology.

[0015] Therefore, preferably, the wall is substantially the inner surface of a hollow cylindrical or rectangular or elliptical hollow molded part defined by the hole. Thus, the wall is substantially parallel to the longitudinal axis of the hole.

[0016] According to the present invention, the groove has a U-shaped cross-section (viewed perpendicular to the longitudinal axis of the hole). Since the groove is recessed into the wall and is not fitted over, for example, a rib protruding from the (free) hole cross-section, the three wall sides of the U-shaped molded portion are surrounded by the voluminous material of the brush head. Therefore, the plastic material does not escape due to the heating and softening of the material that inevitably occurs in the U-shaped molded portion during welding. Thus, the anchor plate piece is securely fixed to both the end face (bottom of the U-shaped molded portion) and the edge face of the U-shaped molded portion.

[0017] In a particular embodiment, to avoid weakening the walls between closely spaced holes in a row, or to ensure sufficient distance between the grooves of adjacent holes, the basic shape of the holes is configured to be circular or elliptical, and the direction of the holes, as defined by the opposing grooves, is offset from the direction of the row of holes by an angle greater than 0°, particularly between 30° and 40°.

[0018] Because the basic shape is simple (circular, elliptical, rectangular, etc.), that is, convex (i.e., without recesses such as ribs or inwardly protruding parts), and the groove is recessed in the wall, the cross-section of the hole can be selectively adapted to the hair bundle into which it is to be inserted.

[0019] At the entrance to the hole, and consequently the entrance to the groove, the combined portion forms a centering portion of the U-shaped form. The centering portion tapers the insertion area or insertion path of the anchor plate piece, viewed radially with respect to the longitudinal axis of the hole. On the one hand, the anchor plate piece is thus centered (for example, with respect to the longitudinal axis of the hole), and on the other hand, during insertion, the anchor plate piece is gradually supplied to the area (referred to as the "certain portion" further down) where it is finally fixed, and at that time, the anchor plate piece is welded almost entirely to the certain portion of the U-shaped form of the groove.

[0020] According to the present invention, in the combination portion, the grooves each have a tapered portion, and the tapered portion has a width that gradually decreases as the distance from the entrance of the hole increases when viewed in a direction perpendicular to the longitudinal axis. Thus, this enables the anchor plate pieces to be symmetrically supplied to the two side walls of the U-shaped forming portion of a fixed portion.

[0021] Following the combination portion, the grooves each have a fixed portion, and the fixed portion has a width and a depth that are each constant along the longitudinal axis when viewed in a direction perpendicular to the longitudinal axis. The width and depth of the U-shaped forming portion in the fixed portion are adapted to the width and thickness of the anchor plate piece. Before the anchor plate piece is fixed by friction welding, the U-shaped forming portion in the hole is slightly narrower than the edge of the anchor plate piece, and the distance between the two bottom surfaces of the grooves facing each other is slightly smaller than the width of the anchor plate piece.

[0022] According to the present invention, the combination portion is configured as both a centering portion and a tapered portion at the same time. According to its advantages, the centering and alignment of the anchor plate pieces are performed in a section that is as short as possible.

[0023] According to the present invention, a fixed portion follows the combination portion.

[0024] In many embodiments, the depth decreases in a stepped manner of two or more. That is, accordingly, the centering portion may have two or more lower portions of straight lines or curves, and the angle of the lower portion with the longitudinal axis gradually decreases as the distance from the entrance of the hole increases.

[0025] In many embodiments, the width decreases in a stepped manner of two or more. Therefore, for this purpose, the tapered portion may have two or more lower portions of straight lines or curves, and the angle of the lower portion with respect to the longitudinal axis gradually decreases as the distance from the entrance of the hole increases.

[0026] In many embodiments, the width of the groove at the entrance of the combination region may be greater than the thickness of the anchor plate piece, particularly at least 5% and at most 100%. Such a groove spread facilitates insertion and improves the symmetry of the load during friction welding at a certain portion. The anchor plate piece is preferably rectangular. In particular, it may be advantageous not to have a chamfer on the short side.

[0027] The present invention also relates to a method for manufacturing a toothbrush comprising a plastic brush head and at least one tuft of bristles fixed within the brush head, having the following steps. a) Prepare a brush head having holes for fixing at least one tuft of bristles, the brush head having a hole with a hole cross-section having a longitudinal axis and a basic shape for accommodating the folded tuft of bristles, and on the wall of the hole, two grooves extending parallel to the longitudinal axis and extending beyond the basic shape of the hole cross-section are formed based on injection molding technology, the grooves having a combination portion having a centering and taper portion following the entrance of the hole, the combination portion having a depth and width that gradually decrease as the distance from the entrance of the hole increases when viewed in a direction perpendicular to the longitudinal axis, step b) Prepare plastic anchor plate pieces for fixing the folded tufts of bristles in the holes respectively, step c) Insert the anchor plate piece having the folded tuft of bristles into the hole, insert the anchor plate piece into the combination portion of the groove, and fix it to the U-shaped forming portion using a friction welding process, having steps.

[0028] Preferably, the grooves each have a constant portion following the combination portion, the constant portion having a width and depth that are constant along the longitudinal axis respectively when viewed in a direction perpendicular to the longitudinal axis.

[0029] [[ID=1,7]] From the following detailed description and the entire scope of the claims, further advantageous embodiments and combinations of features of the present invention are apparent.

Brief Description of the Drawings

[0030] For explaining the examples: [Figure 1] This shows a perspective view of the multiple rows of holes provided on the brush head. [Figure 2] This shows a perspective view of multiple rows of holes into which anchor plate pieces are inserted. [Figure 3] The diagram shows a schematic cross-sectional view of a hole with a centered portion and a fixed portion of the groove, along with an anchor plate piece in which a bundle of hair is introduced into the hole. [Figure 4] Figure 3 shows a schematic plan view of the hole. [Figure 5] Figures 3 and 4 show schematic cross-sectional views of the hole, along with the anchor plate into which the tuft of hair has been folded and introduced. [Figure 6] Figure 5 shows a schematic plan view of the hole. [Figure 7] A schematic cross-sectional view of a hole having a groove with a tapered portion, a centering portion, and a fixed portion is shown. [Figure 8] Figure 7 shows a schematic plan view of the hole. [Modes for carrying out the invention]

[0031] Figure 1 shows a brush head 1 of one embodiment of a toothbrush according to the present invention, as shown in perspective. In this embodiment, multiple rows of multiple cylindrical holes 5 are provided. Therefore, the basic shape of the holes is circular in cross-sectional view. Folded bristle bundles (not shown) and a corresponding number of plastic anchor plate pieces 3 are inserted into the holes. The holes are preferably formed as blind holes in a one-piece brush head.

[0032] The brush head 1 further has holes 5 with a longitudinal axis L1 for each bristle bundle. In this example, all holes 5 are aligned in the same direction along their longitudinal axes, i.e., perpendicular to the upper main surface of the brush head. An anchor plate piece 3 is used to secure each bristle bundle and is fixed within the holes 5. The longitudinal axis L1 is precisely perpendicular to the surface 4 of the brush head in this example.

[0033] According to one advantageous embodiment, the hole 5 itself is neither tapered nor widened; that is, 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.

[0034] Each hole has two grooves 7 and 8 that are recessed in the wall 6 of the hole 5 based on injection molding technology, and are aligned opposite each other and parallel to the longitudinal axis L1. The grooves 7 and 8 are configured to accommodate the anchor plate piece 3. The grooves extend from the entrance of the hole 5 or the surface 4 of the brush head to the depth of the lower half of the hole 5.

[0035] In this embodiment, the alignment direction of the hole groove pairs is not parallel to the row of holes, but is set at an angle of approximately 45° with respect to the direction of the row of holes. The advantage of this is that adjacent hole grooves are spaced relatively far apart from each other.

[0036] Figure 2 is a diagram based on Figure 1, in which an exemplary anchor plate piece 3 is fixed. The anchor plate piece is approximately rectangular. Preferably, the sides are not chamfered. This allows the anchor plate piece to be welded over a wide area in a certain portion of the groove.

[0037] When inserted, the anchor plate piece 3 is tightened between grooves 7 and 8 by ensuring that its appropriate size is at least somewhat larger than the distance between the bottom of groove 7 and the bottom of groove 8 at the end position of the anchor plate piece as shown herein. The anchor plate piece 3 is welded to the U-shaped portions of grooves 7 and 8, for example, by friction welding or ultrasonic excitation of at least one component.

[0038] In one embodiment shown in Figures 3 and 4, the two grooves 9 and 10 extend continuously to the bottom of the hole 11. Figure 4 is a top view of the hole 12, and Figure 3 is a cross-sectional view of the hole 12 in a plane S1. In the upper region, the groove has a centering portion Z1, in which the groove bottom extends obliquely with respect to the longitudinal axis L2. Subsequently, the groove has a fixed portion K1, in which the groove bottom extends parallel to the longitudinal axis L2. Thus, in this case, for tightening and / or welding, the depth T of the grooves 9 and 10 decreases in the brush head 14, starting from the surface 13 or the entrance of the hole 12 when viewed along the longitudinal axis L2, thereby taking advantage of the situation in which the anchor plate piece 15 is supplied symmetrically into the groove when inserted. In this case, the value of depth T, in particular, changes from a maximum value T2 at the entrance of the hole to a minimum value T1 at the end of the centering portion Z1. In other words, the groove depth T is the distance value in the first plane S1 / S2 that passes through the longitudinal axis L2 and perpendicularly through the two grooves. Accordingly, the width B1 is the distance value in the second plane that extends perpendicularly to the first plane.

[0039] Based on Figures 3 to 6, we will now specifically explain how the bristles 2 are secured within the hole 12 by the anchor plate piece 15. The bristles 2 are folded by introducing the anchor plate piece 15 into grooves 9 and 10, so that once secured, the bristles protrude upward from the hole 12 (see Figures 5 and 6). Here, Figure 5 is a view of the cross-section S2 marked in Figure 6. It can also be seen how the anchor plate piece 15 is tightened within the groove.

[0040] The two parts, namely the brush head 14 and the anchor plate piece 15, are made of plastic, specifically the same material, and both parts can be welded together.

[0041] In this embodiment shown in Figures 3 to 6, apart from other optional embodiments, there are yet another optional embodiment that can be used in various embodiments. The width B1 of the groove combination portion is at least 5% (e.g., up to 10%) wider than the thickness D of the anchor plate piece 15, particularly at the hole edge. Where the combination portion abuts a certain portion, the width of the combination portion is the same as the width of the certain portion.

[0042] If a more precise and stable assembly is desired, the groove can be modified by also providing a tapered portion V, according to the embodiments shown in Figures 7 and 8. Figure 7 is a view of portion S3 marked in Figure 8. This embodiment shown therein is based on the embodiments shown in Figures 1 and 2. Viewed in direction S3, the depth gradually decreases. In this case, the width B of grooves 16 and 17 also gradually decreases, respectively, as the distance from the entrance of the hole 20 provided in the surface 18 of the brush head 19 increases. This additional taper acts so that when an anchor plate piece (not shown here) is inserted into the groove, the anchor plate piece is introduced into a certain portion based on friction welding technique, and is centered biaxially and load-bearing symmetrically.

[0043] Furthermore, the embodiments shown in Figures 7 and 8, apart from other optional embodiments, show yet another optional embodiment that can be applied to various embodiments. The centering portion Z2 and the tapered portion V (or just one of the two tapered portions) are both configured in two stages here, that is, in the first stage the groove tapers downward from the brush head surface 18 at a first angle, and in the second stage following the first stage the groove tapers again, but at a second angle smaller than the first angle. In this case the third stage (constant portion K2) up to the stepped portion of grooves 16 and 17 is parallel to the longitudinal axis L3 as shown, but of course it may be configured at an angle. In the embodiments shown in Figures 3 to 6, the taper of the groove depth can also be configured in two or more stages.

[0044] Although the present invention has been described based on its preferred embodiments, many further changes and modifications may be made without departing from the scope of the invention. Accordingly, the appended claims are intended to cover changes and modifications that fall within the actual scope of the invention. This application relates to the invention described in the claims, but also includes the following other embodiments. 1. It is a toothbrush, Plastic brush head (1, 1 4, 19) and comprising at least one folded hair bundle (2) and at least one plastic anchor plate piece (3, 15), The brush head (1, 14, 19) has holes (5, 12, 20) for at least one bristle bundle (2) having longitudinal axes (L1, L2, L3) and a cross-section of a hole having a basic shape for accommodating a folded bristle bundle (2), and anchor plate pieces (3, 15) are fixed within the holes (5, 12, 20) to secure each bristle bundle (2). In a toothbrush in which two grooves (7, 8, 9, 10, 16, 17) are formed on the walls of the aforementioned holes (5, 12, 20) based on injection molding technology, extending parallel to the longitudinal axes (L1, L2, L3) and extending beyond the basic shape of the cross-section of the hole, The anchor plate pieces (3, 15) are fixed by welding to the two grooves (7, 8, 9, 10, 16, 17) which form a U-shaped section. A toothbrush characterized in that the grooves (7, 8, 9, 10, 16, 17) have a combined portion having a centering and tapered portion (Z1, Z2) following the entrance of the hole, and the combined portion has a depth (T) and width (B) that gradually decreases as the distance from the entrance of the hole (5, 12, 20) increases when viewed in a direction (S1, S2, S3) perpendicular to the longitudinal axis (L1, L2, L3). 2. The toothbrush according to the above-mentioned 1, wherein each of the grooves (7.8, 9, 10, 16, 17) has a constant portion (K2), and the constant portion (K2) has a width (B1) and a depth (T1) that are constant along the longitudinal axes (L1, L2, L3) when viewed in a direction (S1, S2, S3) perpendicular to the longitudinal axes (L1, L2, L3). 3. The toothbrush described in 1 or 2 above, wherein the depth (T) decreases in two stages. 4. The width (B) is reduced in two stages, and is one of the toothbrushes described in 1 to 3 above. 5. The width (B1) is particularly at least 5%, and particularly up to 100%, greater than the thickness (D) of the anchor plate pieces (3, 15) of any one of the toothbrushes described in 1 to 4 above. 6. A toothbrush, one of the above 1 to 5, wherein the fixing direction formed by the opposing grooves is at an angle greater than 0° with respect to the direction of the hole row of directly adjacent holes. 7. A method for manufacturing a toothbrush having a plastic brush head (1, 14, 19) and at least one bundle of bristles fixed to the brush head, a) A step of preparing a brush head (1, 14, 19) having a hole for fixing at least one bundle of bristles (2), wherein the brush head (1, 14, 19) has a hole (5, 12, 20) having longitudinal axes (L1, L2, L3) and a hole cross-section having a basic shape for accommodating a folded bundle of bristles (2), and the wall of the hole (5, 12, 20) has two grooves extending parallel to the longitudinal axes (L1, L2, L3) and extending beyond the basic shape of the hole cross-section (7, 8, 9, 10, 16, 17) are formed by injection molding technology, and the grooves (7, 8, 9, 10, 16, 17) have a combined portion having a centering and tapered portion (Z1, Z2) following the entrance of the hole, and the combined portion has a depth (T) and width (B) that gradually decreases as the distance from the entrance of the hole (5, 12, 20) increases when viewed in a direction (S1, S2, S3) perpendicular to the longitudinal axis (L1, L2, L3), step, b) Prepare plastic anchor plate pieces for securing the folded hair bundles (2) in the holes (5, 12, 20), step, c) A method comprising the steps of inserting the anchor plate piece having a folded bundle of hairs into the hole, introducing the anchor plate piece into the groove combination portion, and fixing it to the U-shaped form portion by a friction welding process. 8. The method of 7, wherein each of the grooves (7, 8, 9, 10, 16, 17) has a constant portion (K2), and the constant portion (K2) has a width (B1) and a depth (T1) that are constant along the longitudinal axes (L1, L2, L3) when viewed in a direction (S1, S2, S3) perpendicular to the longitudinal axes (L1, L2, L3).

Claims

1. It is a toothbrush, It comprises a plastic brush head (1, 14, 19), at least one folded bristle bundle (2), and at least one plastic anchor plate piece (3, 15), The brush head (1, 14, 19) has holes (5, 12, 20) for at least one bristle bundle (2) having longitudinal axes (L1, L2, L3) and a cross-section of a hole having a basic shape for accommodating a folded bristle bundle (2), and anchor plate pieces (3, 15) are fixed within the holes (5, 12, 20) to secure each bristle bundle (2). In a toothbrush in which two grooves (7, 8, 9, 10, 16, 17) are formed on the walls of the aforementioned holes (5, 12, 20) based on injection molding technology, extending parallel to the longitudinal axes (L1, L2, L3) and extending beyond the basic shape of the cross-section of the hole, The anchor plate pieces (3, 15) are fixed by welding to the two grooves (7, 8, 9, 10, 16, 17) which form a U-shaped section. A toothbrush characterized in that the grooves (7, 8, 9, 10, 16, 17) have a combined portion having a centering and tapered portion (Z1, Z2) following the entrance of the hole, and the combined portion has a depth (T) and width (B) that gradually decreases as the distance from the entrance of the hole (5, 12, 20) increases when viewed in a direction (S1, S2, S3) perpendicular to the longitudinal axis (L1, L2, L3).

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

3. The toothbrush according to claim 1 or 2, wherein the depth (T) decreases in two stages.

4. The toothbrush according to claim 1 or 2, wherein the width (B) decreases in two stages.

5. The toothbrush according to claim 2, wherein the width (B1) is 5% to 100% greater than the thickness (D) of the anchor plate pieces (3, 15).

6. The toothbrush according to claim 1 or 2, wherein the fixing direction formed by the opposing grooves is at an angle greater than 0° with respect to the direction of the hole row of directly adjacent holes.

7. A method for manufacturing a toothbrush having a plastic brush head (1, 14, 19) and at least one bundle of bristles fixed to the brush head, a) A step of preparing a brush head (1, 14, 19) having a hole for fixing at least one bundle of bristles (2), wherein the brush head (1, 14, 19) has a hole (5, 12, 20) having longitudinal axes (L1, L2, L3) and a hole cross-section having a basic shape for accommodating a folded bundle of bristles (2), and the wall of the hole (5, 12, 20) has two grooves extending parallel to the longitudinal axes (L1, L2, L3) and extending beyond the basic shape of the hole cross-section (7, 8, 9, 10, 16, 17) are formed based on injection molding technology, and the grooves (7, 8, 9, 10, 16, 17) have a combined portion having a centering and tapered portion (Z1, Z2) following the entrance of the hole, and the combined portion has a depth (T) and width (B) that gradually decreases as the distance from the entrance of the hole (5, 12, 20) increases when viewed in a direction (S1, S2, S3) perpendicular to the longitudinal axis (L1, L2, L3), step, b) Prepare plastic anchor plate pieces for securing the folded hair bundles (2) in the holes (5, 12, 20), step, c) A method comprising the steps of inserting the anchor plate piece having a folded bundle of hair into the hole, introducing the anchor plate piece into the groove combination portion, and fixing it to the U-shaped form portion by a friction welding process.

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

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