Toothbrush

Abstract

To provide a toothbrush high in plaque removal power.SOLUTION: A toothbrush includes a handle body and a brush molded body formed by soft resin. The brush molded body has a head base part, and a plurality of filaments extending from a supporting surface of the head base in a long axial direction. The filament has a recess which opens on one side in a first direction and is recessed on the other side in the first direction. The recess has: a first opening end located at an end on one side in the first direction and located on one side in a second direction; a second opening end located at the end part on one side in the first direction and located on the other side in the second direction; and a bottom end part located on the farthest other end side in the first direction and located at a prescribed position in the second direction. Of the plurality of filaments, second filaments adjacent to one side in the first direction relative to a first filament has at least a part of an outer wall located on the farthest other side in the first direction located between a first border line passing the bottom end part in the first filament and the first opening end and a second border line passing the bottom end part and the second opening end.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a toothbrush.

Background Art

[0002] An integrally molded toothbrush that is manufactured only by an injection molding machine has been proposed (for example, Patent Document 1). Since the integrally molded toothbrush integrally molds filaments, which are cleaning bodies, and a head base portion (or a head portion), it does not require material procurement for the cleaning bodies and a hair implanting machine, and has an advantage that it can be manufactured at a lower cost than a hair-implanted toothbrush.

[0003] Since the integrally molded toothbrush produces a cleaning body by injection molding, it is necessary to make each filament thicker than that of a hair-implanted toothbrush from the viewpoint of ensuring moldability. Therefore, a resin with low hardness is often used to ensure comfort. In addition, the number of hairs per unit area is limited, the filament density is low, and the distance between filaments is far compared to a hair-implanted toothbrush.

[0004] These characteristics have a problem of causing a decrease in the plaque removal power. Patent Document 2 discloses filaments having a polygonal cross-sectional shape in order to improve the plaque removal power under the condition of using the above-mentioned low-hardness resin and having a sparse filament density.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The filament formed of a low-hardness resin is soft and easily bends in all directions, front, back, left, and right. Therefore, during brushing, it is difficult for the brushing force to be transmitted to the desired site. Also, if the filament density is low, many filament tips cannot be applied to the object to be cleaned. Furthermore, due to the large distance between filaments, contact between filaments is unlikely to occur during brushing, and each filament behaves independently, resulting in a state where the interaction is extremely small. As a result, there is a problem that the conventional filaments in an integrally molded toothbrush have low plaque-removing power.

[0007] On the other hand, the filament disclosed in Patent Document 2 controls the bending of the filament in units of one by making the cross-sectional shape polygonal under the constraints of the filament density and the number of filaments resulting from the viewpoint of ensuring moldability, aiming to improve the plaque-removing power. However, measures in units of one filament are insufficient to solve this problem.

[0008] The present invention has been made in consideration of the above points, and an object thereof is to provide a toothbrush having high plaque-removing power.

Means for Solving the Problems

[0009] The present invention has the following aspects. [1] A toothbrush comprising a handle body and a brush formed body made of a soft resin and disposed on one side in the longitudinal direction of the handle body, wherein the brush formed body has a head base portion and a plurality of filaments extending in the major axis direction from a support surface located on the front side in the thickness direction of the head base portion, and the filaments have a recess that opens to one side in a first direction parallel to the support surface and is recessed on the other side in the first direction in a cross-section parallel to the support surface, the recess being located at an end on one side in the first direction and having a first opening end located on one side in a second direction intersecting the first direction, a second opening end located on the other side in the second direction at an end on one side in the first direction, and a bottom end portion located at the most other side in the first direction and at a predetermined position in the second direction, and among the plurality of filaments, a second filament adjacent to a first filament on one side in the first direction has at least a part of an outer wall located at the most other side in the first direction positioned between a first boundary line passing through the bottom end portion and the first opening end in the first filament and a second boundary line passing through the bottom end portion and the second opening end. [2] The toothbrush according to [1], wherein the recess extends in the major axis direction and is provided at least on the tip side of the filament. [3] The cross-sectional shape of the recess in the first filament is congruent or similar to the cross-sectional shape of the outer wall located on the other side in the first direction in the second filament. The toothbrush according to [1] or [2]. [4] The toothbrush according to any one of [1] to [3], wherein the filament has one recess. [5] The toothbrush according to any one of [1] to [4], wherein the cross-sectional shape of the filament including the recess is V-shaped, U-shaped, or C-shaped. [6] The toothbrush according to any one of [1] to [5], wherein the first direction is a width direction orthogonal to the longitudinal direction and the thickness direction or the longitudinal direction. [7] The angle at which the first boundary line and the second boundary line intersect is greater than 30° and less than 150°, the toothbrush according to any one of [1] to [6] above.

Effect of the Invention

[0010] In the present invention, a toothbrush with high plaque removal power can be provided.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Mode for Carrying Out the Invention

[0012] Hereinafter, embodiments of the toothbrush of the present invention will be described with reference to FIGS. 1 to 13. The following embodiments show one aspect of the present invention, do not limit this invention, and can be arbitrarily changed within the scope of the technical idea of the present invention. Also, in the following drawings, in order to make each configuration easier to understand, the actual structure, scale, number, etc. in each structure are made different.

[0013] FIG. 1 is a front view of the brush molded body 20 and the toothbrush 1 according to this embodiment. FIG. 2 is a side view of the brush molded body 20 and the toothbrush 1. The toothbrush 1 includes a rod-shaped handle body 10 and a brush molded body 20. The handle body 10 and the brush molded body 20 are separate members. The brush molded body 20 can be detachably attached (inserted) to the handle body 10. The brush molded body 20 attached to the handle body 10 is supported by the handle body 10. The brush molded body 20 is formed of a soft resin. The handle body 10 is formed of a hard resin.

[0014] Note that the handle body 10 and the brush molded body 20 may include separate detachable members, or may be integrally fixed and molded without being detachable. As an integrally molded configuration, after molding the handle body 10 by primary molding, the brush molded body 20 may be insert-molded in a CAP manner by secondary molding, or a configuration in which the brush molded body 20 penetrating the head portion in the thickness direction is insert-molded may also be used.

[0015] Note that the front in this embodiment refers to the side (the upper side in FIG. 2) where the filament 23 described later protrudes, among the thickness directions (hereinafter simply referred to as the thickness direction) that are the normal directions of the support surface 21a (details will be described later) of the brush molded body 20. In the thickness direction of the brush molded body 20, the side opposite to the front side is appropriately referred to as the back side. Further, the longitudinal direction of the handle body 10 (hereinafter simply referred to as the longitudinal direction), which is the direction in which the handle body 10 is inserted into the brush molded body 20 (hereinafter simply referred to as the insertion direction), is orthogonal to the above normal direction. In the longitudinal direction, the side where the handle body 10 is attached to the brush molded body 20 is defined as the rear end side, and the side opposite to the rear end side is appropriately referred to as the front end side. Further, the direction orthogonal to the above normal direction and the insertion direction is the width direction of the brush molded body 20 (hereinafter simply referred to as the width direction). The major axis direction in this embodiment is the direction in which the filament 23 extends and is a direction parallel to the above normal direction.

[0016] FIG. 3 is a front view of the handle body 10. As shown in FIG. 3, the handle body 10 includes a rod-shaped handle portion 11 and a fitting protrusion 12 provided at the tip of the handle portion 11 and protruding toward the tip side in the longitudinal direction of the handle portion 11. In the toothbrush 1, the brush molded body 20 is attached by covering the fitting protrusion 12 of the handle body 10 by inserting the fitting protrusion 12 into the brush molded body 20 described later.

[0017] The handle body 10 is formed of a hard resin. As an example of the hard resin, resins having a flexural modulus (JIS K7171) of 1500 MPa or more and 3000 MPa or less can be exemplified. Specifically, for example, polybutylene terephthalate resin (PBT), polypropylene resin (PP), polyacetal resin (POM), polyester resin (PCTA), polyethylene terephthalate copolymer (PETG), and high-density polyethylene (HDPE) can be exemplified. Among these, considering the manufacturing cost, polypropylene resin, which is a general-purpose resin, is preferable, and considering the strength, polybutylene terephthalate resin and polyacetal resin are preferable.

[0018] The front view shape of the handle portion 11 of the present embodiment gradually narrows in width from the front end side toward the rear end side, then extends with a constant width, and then gradually curves to become wider and then narrower. The rear end portion of the handle portion 11 has a substantially semicircular shape in the front view.

[0019] As shown in FIG. 2, the side view shape of the handle portion 11 extends with a constant width from the front end side toward the rear end side, and then gradually widens to the maximum thickness that becomes the finger contact portion. The side view shape of the handle portion 11 gradually curves to become narrower from the finger contact portion of the maximum thickness toward the rear end side. The rear end portion of the handle portion 11 has a substantially semicircular shape in the side view.

[0020] In the present invention, the shape of the handle portion 11 is not limited to the shape of this example and can be appropriately set in consideration of strength, operability, design, etc. The dimensions of the handle portion 11 are not particularly limited and can be appropriately set. For example, the length of the handle portion 11 can be 100 to 200 mm.

[0021] The fitting projection 12 is a portion covered by the brush molded body 20 when the brush molded body 20 is attached to the handle body 10. The rear end of the fitting projection 12 is the rear end position of the brush molded body 20 when the brush molded body 20 is attached to the handle body 10.

[0022] FIG. 4 is an enlarged front view of the fitting projection 12. As shown in FIG. 4, the fitting projection 12 has a base portion 13 provided on the front end side of the handle portion 11 and a tip portion 14 provided at the tip of the base portion 13. Although not shown, the base portion 13 and the tip portion 14 have steps with respect to the handle portion 11 on both the front side and the back side and are formed with the same thickness that is thinner than the handle portion 11.

[0023] FIG. 5 is a front view of the brush molded body 20. FIG. 6 is a side view of the brush molded body 20. As shown in FIGS. 5 and 6, the brush molded body 20 includes a head base portion 21 having a substantially rectangular shape in a front view, and a plurality of filaments 23 provided on the front surface of the head base portion 21.

[0024] As the soft resin constituting the brush molded body 20, various elastomers can be used, but polyurethane is preferable. Polyurethane tends to have a higher tensile strength than other elastomers such as styrene-based and polyester-based elastomers. Therefore, by using polyurethane as the soft resin, mechanical strength can be ensured even with a thin wall, and breakage during fitting of the handle body 10 and the fitting hole 22 and during use of the toothbrush 1 can be suppressed.

[0025] In the polyurethane, any one of saturated / unsaturated hydrocarbons having 10 or more carbon atoms, higher alcohols, fatty acid amides, fatty acid esters, low molecular weight polyethylene, polyethylene glycol (PEG), fatty acid metal salts, long-chain fatty acids, fatty acid glycerin, liquid paraffin, silicone, or a combination thereof in an amount of 0.01 to 1.0 wt% (mass%) is blended and functions as a lubricant and a mold release agent.

[0026] In addition, polyurethane has a wider range of selectable hardness compared to the above-mentioned other elastomers, and depending on the thickness of the brush molded body 20, it is possible to select the resin hardness in consideration of its usability (for example, bending of the tip of the brush molded body). The hardness of the polyurethane is preferably Shore 90A or more and 100A or less, or Shore 40D or more and 70D or less. When the hardness of the polyurethane is softer than Shore 90A, it tends to deform when formed in a thin wall, resulting in a weak fit and making the brush molded body 20 likely to fall off during use of the toothbrush 1. When the hardness of the polyurethane is harder than Shore 70D, there is a possibility of pain when the tip hits the oral tissue when the back surface of the head base portion 21 is inclined. By setting the hardness of the polyurethane to be 90A or more and 70D or less, it is possible to suppress the brush molded body 20 from falling off during use of the toothbrush 1 and the occurrence of pain when the tip of the head base portion 21 hits.

[0027] Also, as the polyurethane, from the viewpoint of ensuring water resistance and antibacterial properties, it is preferable to use an ether-based polyurethane.

[0028] The head base portion 21 has a fitting hole 22. The fitting hole 22 extends in the insertion direction and opens to the end face 21b on the rear end side (one side). FIG. 7 is a cross-sectional view in a plane parallel to the support surface 21a including the fitting hole 22. As shown in FIG. 7, the fitting hole 22 has a first portion 33 that opens to the end face 21b and a second portion 34 that is located deeper than the first portion 33. As shown in FIG. 6, the first portion 33 and the second portion 34 are arranged separately from the support surface 21a and the back surface 21c of the head base portion 21, respectively.

[0029] The head base portion 21 has a protrusion 35 that is substantially at the center in the insertion direction in the fitting hole 22 and is located between the first portion 33 and the second portion 34. The protrusions 35 are provided on both sides in the width direction of the fitting hole 22. The protrusions 35 are provided at positions where they fit with the depressions 15 when the fitting protrusions 12 of the handle body 10 are inserted into the fitting holes 22. The protrusion 35 has an arc shape with the center of the arc on the outer side in the width direction and convex on the inner side.

[0030] When the fitting protrusion 12 on the handle body 10 is inserted into the fitting hole 22 on the head base portion 21, the base portion 13 fits into the first portion 33, the tip portion 14 fits into the second portion 34, and the protrusion 35 fits into the depression 15. Thereby, the handle body 10 and the head base portion 21 are integrated.

[0031] [First Embodiment of Filament 23] The filament 23 is substantially columnar, protruding forward from the support surface 21a located on the front side in the thickness direction of the head base portion 21 and extending in the major axis direction. A plurality of filaments 23 are arranged in a lattice pattern when viewed from the front. The support surface 21a of the head base portion 21 is a plane parallel to the width direction and the insertion direction. The support surface 21a is disposed at the base end position of the filament 23 in the thickness direction.

[0032] As shown in FIG. 8, the filament 23 is formed in a V shape in a cross section parallel to the support surface 21a. Hereinafter, unless otherwise specified, the cross-sectional shape of the filament 23 will be described.

[0033] In FIG. 8, a first filament 23A and a second filament 23B are shown as a plurality of filaments 23. The second filament 23B is arranged apart in the same direction on the rear end side in the longitudinal direction corresponding to one side in the first direction with respect to the first filament 23A. In the present embodiment, the positions of the first filament 23A and the second filament 23B in the width direction are the same.

[0034] The filament 23 forms a side 25 extending in the width direction of the triangle and has an outer wall located on the rear end side. The filament 23 has one concave portion 24 that opens to the outer wall that is one side of the triangle. The concave portion 24 extends in the major axis direction. The concave portion 24 is a triangle that opens to the rear end side on the side 25 of the filament 23. The filament 23 is formed in a V shape that opens to the rear end side by providing the triangular concave portion 24 on the triangular outer wall.

[0035] Since the filament 23 has the concave portion 24, the second moment of inertia of the cross section of the filament 23 becomes non-uniform according to the direction along the support surface 21a, anisotropy occurs in the way the filament 23 bends, and it becomes easier to bend in a specific direction. As a result, the force during brushing is easily transmitted to a desired site (Effect 1).

[0036] In addition, since the second filament 23B is arranged in the same direction on the side where the concave portion 24 of the first filament 23A opens, the unevenness of the adjacent first filament 23A and second filament 23B is likely to overlap during brushing, and the distance between the first filament 23A and the second filament 23B becomes close. Therefore, even if the filaments 23 are arranged at the same density / number as in the conventional case where formability can be ensured, the dynamic tip density during brushing can be relatively higher compared to the conventional case (Effect 2).

[0037] Furthermore, since the unevenness of the adjacent first filament 23A and second filament 23B is likely to overlap during brushing, it is induced that the overlapping portion behaves as a thicker filament 23. Generally, the greater the thickness of a structure, the higher its rigidity, so this can increase the resistance when the filament 23 bends (Effect 3).

[0038] In addition, since the unevenness of the adjacent first filament 23A and second filament 23B is likely to overlap during brushing, the contact and non-contact of the first filament 23A and the second filament 23B are repeated during brushing. Therefore, in addition to the conventional "scraping", the oral cavity dirt can be removed by "pinching" (Effect 4).

[0039] In order to achieve the above effects, it is preferable that three or more of the plurality of filaments 23 are arranged continuously. By arranging three or more filaments 23 continuously, at least one filament 23 has both concave and convex functions, so that the above effects can be effectively exhibited.

[0040] In the recess 24, one side in the width direction corresponding to the second direction that intersects the first direction and is the end on the rear end side is defined as the first opening end 26A, the other side in the width direction which is the end on the rear end side is defined as the second opening end 26B, and the most front end side corresponding to the most other side in the first direction and at a predetermined position in the width direction has the apex of the triangle as the bottom end 26C. A first boundary line 27A passing through the bottom end 26C and the first opening end 26A is set, and a second boundary line 27B passing through the bottom end 26C and the second opening end 26B is set.

[0041] As the second filament 23B disposed on the side where the recess 24 opens with respect to the first filament 23A, at least a part of the outer wall located at the most front end side is located between the first boundary line 27A and the second boundary line 27B. In FIG. 8, the apex 28 of the outer wall in the second filament 23B is located between the first boundary line 27A and the second boundary line 27B. Thereby, when the second filament 23B is bent, it is easily inserted into the recess 24 of the first filament 23A and is likely to overlap, and the above effect is easily obtained.

[0042] The recess 24 extends in the major axis direction in the plurality of filaments 23 and is provided at least on the tip side. The "tip side" is defined as 60% of the tip side when the length of the filament 23 is taken as 100%. Since the deflection during brushing is minute on the base end side of the filament 23 and the possibility of adjacent filaments 23 contacting each other is low, there is no problem even if the recess 24 is not provided. If the range where the recess 24 is provided is less than 60%, a state occurs where there is no recess in the region where the filament 23 touches the teeth or tooth necks, which is not preferable. As the range where the recess 24 is provided in the filament 23, 60% or more of the tip side is more preferable, and 80% or more is even more preferable.

[0043] The cross-sectional shape of the recess 24 in the first filament 23A is preferably congruent or similar to the cross-sectional shape of the outer wall 25B located on the front end side in the second filament 23B. As a result, when the adjacent first filament 23A and second filament 23B overlap, the contact area between the inner wall 24A and the outer wall 25B of the recess 24 increases, and the above-described effects 2-4 are more likely to be exhibited.

[0044] In the filament 23, the distance L2 between the line segment connecting the first opening end 26A and the second opening end 26B, which is the depth of the recess 24, and the bottom end portion 26C is preferably 0.1 mm or more. Further, the distance L2 is preferably at least twice the distance L1 between the bottom end portion 26C, which is the thickness of the filament 23 in the depth direction of the recess 24, and the apex 28 of the outer wall. The cross-sectional area of the recess 24 is preferably S of 0.0013 cm 2 or more, and more preferably 0.0050 cm 2 or more.

[0045] Also, the cross-sectional area of the recess 24 is preferably 1% or more, more preferably 10% or more, and even more preferably 20% or more of the virtual cross-sectional area of the filament 23 including the recess 24. When the depth L2, cross-sectional area, and cross-sectional area ratio of the recess 24 are below the lower limit, the difference in flexibility in the direction of the presence or absence of the recess 24 becomes small, and the above-described effect 1 is less likely to be exhibited. Also, the contact state between the tip sides of adjacent filaments 23 is not stable, and the above-described effects 2-4 are less likely to be exhibited.

[0046] Also, the cross-sectional area of the recess 24 is preferably 85% or less, more preferably 65% or less, and even more preferably 45% or less of the virtual cross-sectional area of the filament 23 including the recess 24. When the cross-sectional area ratio of the recess 24 exceeds the upper limit, the resistance when bending is insufficient even when the tip sides of adjacent filaments 23 overlap, and the above-described effect 3 is less likely to be exhibited.

[0047] In the filament 23, it is preferable that the outer wall shape and the inner wall of the recess 24 are in a similar relationship. In adjacent filaments 23, the inner wall 24A and the outer wall 25B of the recess 24 are congruent, and in one filament 23, the outer wall and the inner wall of the recess 24 are in a similar relationship, so that when adjacent filaments 23 come into contact with each other, the contact area becomes larger, and the above effects 2-4 are more likely to be exerted.

[0048] The apex angle of the apex 28 in the first filament 23A is preferably equal to or greater than the apex angle of the apex 28 in the second filament 23B. When the apex angle of the apex 28 in the second filament 23B is larger than the apex angle of the apex 28 in the first filament 23A, the tip of the second filament 23B is less likely to fit into the recess 24 in the first filament 23A and does not contact stably, so that the above effects 2-4 are less likely to be exerted.

[0049] The direction in which the recess 24 in the filament 23 opens is not limited to the longitudinal direction and may be the width direction. The distance between the bottom end 26C of the first filament 23A and the apex 28 of the second filament 23B is preferably 1.5 mm or less, and the smaller the better. When the above distance exceeds the upper limit, it becomes difficult for the first filament 23A and the second filament 23B to come into contact during brushing, and the above effects 2-4 are less likely to be exerted. It is more preferable that the apex 28 in the second filament 23B is closer to the bottom end 26C of the first filament 23A than the line segment connecting the first opening end 26A and the second opening end 26B in the first filament 23A.

[0050] The number of recesses 24 in the filament 23 is preferably one. Since there is one recess in the filament 23, the bending anisotropy of the filament 23 becomes clearer, and the above effects are further enhanced.

[0051] The intersection angle θ between the first boundary line 27A and the second boundary line 27B is preferably greater than 30° and less than 150°, more preferably greater than 45° and less than 120°. When the intersection angle θ is 30° or less, the filament 23 is likely to bend in the direction orthogonal to the opening direction, and it becomes difficult for the filaments 23 adjacent in the opening direction to overlap, making it difficult to exhibit the above-described effects 2-4. Further, when the intersection angle θ is 150° or more, the resistance to bending per filament 23 is weak, and even when overlapping with the adjacent filaments 23, the resistance to bending becomes insufficient, making it difficult to exhibit the above-described effect 3. Note that the filament 23 is preferably symmetric, but it is not necessarily symmetric.

[0052] As described above, in the toothbrush 1 of the present embodiment, since the concave portion 24 is provided in the filament 23, the filament 23 is likely to bend in a specific direction, and a part of the outermost wall 25B on the front end side in the second filament 23B adjacent to the rear end side with respect to the first filament 23A among the plurality of filaments 23 is located between the first boundary line 27A and the second boundary line 27B. Therefore, when the first filament 23A and the second filament 23B are bent, the unevenness is likely to overlap. Therefore, in the toothbrush 1 of the present embodiment, the plaque removing power can be increased.

[0053] [Second Embodiment of Filament 23] Subsequently, a second embodiment of the filament 23 will be described with reference to FIG. 9. In this figure, the same elements as those of the first embodiment shown in FIGS. 1 to 8 are denoted by the same reference numerals, and the description thereof is omitted.

[0054] In the above first embodiment, a configuration in which the filaments 23 adjacent in the longitudinal direction are arranged in a lattice pattern at the same position in the width direction was exemplified. In the second embodiment, as shown in FIG. 9, the filaments 23 adjacent in the longitudinal direction are arranged in a staggered pattern at different positions in the width direction.

[0055] More specifically, the second filament 23B adjacent to the first filament 23A on the rear end side has a recess 24 provided in the same direction as the first filament 23A, and is arranged at a different position in the width direction from the first filament 23A. The apex 28 of the second filament 23B is located between the first boundary line 27A and the second boundary line 27B of the first filament 23A, respectively.

[0056] Also in this embodiment, since the apex 28 of the second filament 23B is located between the first boundary line 27A and the second boundary line 27B of the first filament 23A, respectively, when the first filament 23A and the second filament 23B are bent, the unevenness is likely to overlap. Therefore, in this embodiment, the same operations and effects as those of the first embodiment can be obtained.

[0057] In addition, the filaments 23, in addition to the lattice arrangement and the staggered arrangement, may not have the same direction in which the recess 24 opens, as shown in FIG. 10 as a modification of the second embodiment. The second filament 23B shown in FIG. 10 is arranged in a direction rotated about an axis extending in the thickness direction with respect to the first filament 23A, including the recess 24 and the outer wall 25B.

[0058] The second filament 23B arranged in a direction rotated with respect to the first filament 23A has its apex 28 located between the first boundary line 27A and the second boundary line 27B of the first filament 23A, respectively, as described above. Thereby, when the first filament 23A and the second filament 23B are bent, the unevenness is likely to overlap.

[0059] Therefore, by applying this modification, for example, the present invention can be applied when the filaments 23 are arranged radially along the support surface 21a.

[0060] [Third Embodiment of Filament 23] Subsequently, a third embodiment of the filament 23 will be described with reference to FIGS. 11 to 13. In these figures, the same reference numerals are given to the components that are the same as those of the first embodiment shown in FIGS. 1 to 8, and the description thereof will be omitted.

[0061] In the above-described embodiment, the concave portion 24 has a triangular shape, and the outer wall 25B also has a triangular shape. In the third embodiment, a configuration in which at least one of the concave portion 24 and the outer wall 25B is different from the triangular shape will be described.

[0062] As shown in FIG. 11, for the filament 23C, the concave portion 24 has a triangular shape, and the outer wall 29 has a rectangular shape. When the filaments 23C are adjacent to each other in the direction in which the concave portion 24 opens, one of the filaments 23C may be arranged such that a part of the side of the outer wall 29 facing the concave portion 24 is located between the first boundary line and the second boundary line described above.

[0063] For the filament 23D, the concave portion 24 has a triangular shape, and the outer wall 29 has a circular shape. For the filament 23E, the concave portion 24 has a triangular shape, and the outer wall 29 has an X shape. The filament 23E has four concave portions 24 with different opening directions.

[0064] Also for the filaments 23D and 23E, when filaments 23D and 23E of the same shape are adjacent to each other in the direction in which the concave portion 24 opens, at least a part of the outer wall 29 of one of the adjacent filaments 23D and 23E is located between the first boundary line and the second boundary line defined by the concave portion 24 in the other of the adjacent filaments 23D and 23E, and one of the filaments 23D and 23E may be arranged.

[0065] As shown in FIG. 12, for the filament 23F, the concave portion 24 has a trapezoidal shape, and the outer wall 29 has a triangular shape. The bottom end portion 26C of the trapezoidal concave portion 24 is defined such that the central position is a predetermined position among the sides located on the side most opposite to the opening side. For the filament 23G, the concave portion 24 has a trapezoidal shape, and the outer wall 29 is formed in a U shape having a trapezoidal shape. The filament 23H is formed in a U-shape in which the recess 24 is trapezoidal and the outer wall 29 is rectangular.

[0066] Regarding the filaments 23F, 23G, and 23H as well, when filaments 23F, 23G, and 23H having the same shape are adjacent to each other in the direction in which the recess 24 opens, at least a part of the outer wall 29 of one of the adjacent filaments 23F, 23G, and 23H is located between the first boundary line and the second boundary line defined by the recess 24 in the other of the adjacent filaments 23F, 23G, and 23H, and one of the filaments 23F, 23G, and 23H may be arranged accordingly.

[0067] As shown in FIG. 13, the filament 23J has a semi-circular recess 24 and a semi-circular outer wall 29. Regarding the filament 23J as well, when filaments 23J having the same shape are adjacent to each other in the direction in which the recess 24 opens, at least a part of the outer wall 29 of one of the adjacent filaments 23J is located between the first boundary line and the second boundary line defined by the recess 24 in the other of the adjacent filaments 23J, and one of the filaments 23J may be arranged accordingly.

[0068] The combination of the recess 24 and the outer wall 29 in the filaments 23D to 23J described above is an example, and when filaments 23 having the same shape are adjacent to each other in the direction in which the recess 24 opens, various shapes can be selected as long as at least a part of the outer wall 29 of one of the adjacent filaments 23 is located between the first boundary line and the second boundary line defined by the recess 24 in the other of the adjacent filaments 23.

[0069] Also, it is not necessary for filaments 23 having the same shape to be adjacent to each other, and a configuration in which a plurality of types of filaments 23 having different shapes of at least one of the recess 24 and the outer wall 29 are arranged adjacent to each other may be used.

[0070] The preferred embodiments of the present invention have been described above with reference to the accompanying drawings. Needless to say, the present invention is not limited to such examples. The various shapes and combinations of the constituent members shown in the above examples are merely examples, and can be variously changed based on design requirements and the like without departing from the gist of the present invention.

[0071] For example, in the above embodiment, the configuration in which the filament 23 is straight hair is exemplified, but the present invention is not limited to this configuration, and it may be tapered hair with a tapered tip. When the filament 23 has a tapered shape, the problem that the filament 23 formed of a soft resin is likely to bend back and forth and left and right becomes more prominent. However, by having the concave portion 24, the above effects 1-4 occur. In particular, effect 1 (anisotropy occurs in the bending direction) and effect 3 (the resistance to bending increases due to overlapping) occur, so that while suppressing the "softness" of the tapered hair, the advantages of using tapered hair such as gap invasiveness can be enjoyed.

Explanation of Reference Numerals

[0072] 1... toothbrush, 10... handle body, 12... fitting projection, 20... brush molded body, 21... head base portion, 21a... support surface, 22... fitting hole, 23, 23C, 23D, 23E, 23F, 23G, 23H, 23J... filament, 23A... first filament, 23B... second filament, 24... concave portion, 26A... first opening end, 26B... second opening end, 26C... bottom end portion, 27A... first boundary line, 27B second boundary line

Claims

1. A handle body, A brush molded body formed of a soft resin and disposed on one side in the longitudinal direction of the handle body, comprising: The brush molded body includes: A head base portion, A plurality of filaments extending in the major axis direction from a support surface located on the front side in the thickness direction of the head base portion, having: The filament has a recess that opens to one side in a first direction parallel to the support surface and is recessed on the other side in the first direction in a cross section parallel to the support surface. The recess includes: A first opening end located at one end on one side in the first direction and on one side in a second direction intersecting the first direction, A second opening end located at one end on one side in the first direction and on the other side in the second direction, A bottom end portion located on the other most side in the first direction and at a predetermined position in the second direction, having: Among the plurality of filaments, a second filament adjacent to a first filament on one side in the first direction has at least a part of an outer wall located on the other most side in the first direction between a first boundary line passing through the bottom end portion and the first opening end in the first filament and a second boundary line passing through the bottom end portion and the second opening end. The toothbrush.

2. The recess extends in the major axis direction and is provided at least on the tip side of the filament, The toothbrush according to claim 1.

3. The cross-sectional shape of the recess in the first filament is congruent or similar to the cross-sectional shape of the outer wall located on the other side in the first direction in the second filament, The toothbrush according to claim 1 or 2.

4. The filament has one recess, The toothbrush according to claim 1 or 2.

5. The cross-sectional shape of the filament including the recess is V-shaped, U-shaped or C-shaped. The toothbrush according to claim 1 or 2.

6. The first direction is the width direction or the longitudinal direction that is orthogonal to the longitudinal direction and the thickness direction. The toothbrush according to claim 1 or 2.

7. The angle at which the first boundary line and the second boundary line intersect is greater than 30° and less than 150°. The toothbrush according to claim 1 or 2.

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