toothbrush

Abstract

To provide a toothbrush in which, while a filling amount of a material is reduced for the entire volume of a handle part, deformation hardly occurs when the toothbrush is moved left, right, front back, up and down, draining is excellent, and in the case where synthetic resin is used for the material of the handle part, the used amount of the synthetic resin can be reduced, so that the toothbrush has a low load on the global environment.SOLUTION: A toothbrush 11 has a head part 12 and a handle part 13, with a brush 12a implanted in the head part 12. The head part 12 is guided into the oral cavity, with the handle part 13 held by hand, and dirt in the oral cavity is cleaned. In the handle part 13, there is provided a cubic conformation 13a that bulges out in a direction parallel to the implantation direction of the brush 12a. The cubic conformation 13a is provided with a plurality of cavities 13b that penetrate in the bulging-out direction of the handle part 13.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a toothbrush, and more particularly to a toothbrush having a structure capable of reducing the filling amount of a material with respect to the total volume of the handle portion.

Background Art

[0002] Conventionally, there is a toothbrush having a head portion and a handle portion, with bristles implanted in the head portion, the handle portion being gripped to guide the head portion into the oral cavity to clean the dirt in the oral cavity, and a recess being formed in the handle portion in the longitudinal direction (Patent Document 1).

[0003] Such a conventional toothbrush with a recess formed in the handle portion can reduce the filling amount of the material corresponding to this recess with respect to the total volume of the handle portion. Therefore, the toothbrush can be made lighter, which is easy to use even for elderly people with weak gripping force by fingers, and also has the advantages of being easy to carry and transport.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Conventional toothbrushes with a recess in the handle lack overall strength because this recess is a large cavity and lacks a structure to reinforce the walls of this cavity. Therefore, when gripping the handle and guiding the head into the oral cavity to clean the plaque, the toothbrush is prone to bending, twisting, and other elastic deformations, making it difficult to use. Furthermore, repeated elastic deformations or the application of strong force will eventually lead to plastic deformation, cracking, and deterioration, resulting in a short lifespan for the toothbrush.

[0006] Furthermore, conventional toothbrushes tend to accumulate saliva and moisture in the recesses during brushing, making them unsanitary.

[0007] Therefore, the present invention aims to provide a toothbrush that reduces the amount of material filling relative to the total volume of the handle, is less prone to deformation when moved left, right, forward, backward, up, and down, and has excellent water drainage, while addressing these challenges. [Means for solving the problem]

[0008] (1) The present invention provides a toothbrush having a head portion and a handle portion, wherein a brush is implanted in the head portion, the handle portion is grasped and the head portion is guided into the oral cavity to clean dirt in the oral cavity, wherein the handle portion has a three-dimensional structure that bulges in a direction parallel to the direction in which the bristles of the brush are implanted, and the three-dimensional structure has a plurality of voids that penetrate in the direction of the handle portion bulge, which is the direction in which the handle portion bulges. Furthermore, the three-dimensional structure has a plurality of voids that penetrate in the thickness direction, which is the direction in which the handle portion bulges, and a plurality of beam-like portions that have a beam-like shape extending in the length direction which is approximately the central axis of the toothbrush and have a vertically elongated cross-section whose longitudinal direction coincides with the thickness direction, and each of the beam-like portions may constitute the inner wall of each of the voids in the length direction. Furthermore, the handle portion has a three-dimensional structure that bulges in a direction parallel to the direction in which the bristles of the brush are planted, and has a pair of outer frame portions that extend in a bifurcated manner away from the head portion, and the three-dimensional structure has a plurality of voids that penetrate in the thickness direction, which is the direction in which the handle portion bulges, and a plurality of beam-like portions, and the outer edge in the width direction, which is the direction perpendicular to the length direction when viewed in the thickness direction, is defined by the outer frame portions, and each beam-like portion has a beam-like shape that extends in the length direction, which is approximately the axis of the center of the toothbrush, and has a vertically elongated cross-section whose longitudinal direction coincides with the thickness direction, and constitutes the inner wall of each void in the length direction, and the cross-sections may be approximately parallel to each other.

[0009] In other words, because the handle portion of the toothbrush of the present invention has multiple voids, the amount of material filling required is less compared to toothbrushes without voids, thus enabling weight reduction. Furthermore, despite the multiple voids in the handle portion, it forms a three-dimensional structure that bulges in the direction of handle expansion, allowing the user to easily grasp the handle portion by grasping this three-dimensional structure with their fingers, or with their fingers and palm.

[0010] Furthermore, because the handle has multiple voids, even though the amount of material filling relative to the total volume is low, its three-dimensional structure compensates for the overall strength of the toothbrush, making it resistant to deformation caused by bending or twisting in any direction.

[0011] Furthermore, because the multiple voids penetrate the handle portion, less saliva and moisture accumulate in these voids during brushing, resulting in good drainage.

[0012] (2) The three-dimensional structure may also include a beam-like portion in the direction of the toothbrush's approximate central axis, and the cross-section of the beam-like portion in the direction of the handle portion's bulge may have a vertically elongated shape in which the longitudinal direction coincides with the direction of the handle portion's bulge.

[0013] In other words, because the cross-section of the beam-shaped portion is elongated vertically in the direction of the handle's bulge, the second moment of area of ​​the beam-shaped portion is large when attempting to bend it in the direction of the handle's bulge. As a result, the bending stiffness (bending rigidity) of the beam-shaped portion is large when attempting to bend it in the direction of the handle's bulge. Therefore, the toothbrush of the present invention is particularly resistant to bending in the direction of the handle's bulge, and deformation is less likely to occur even when moving it in the vertical direction, which is the direction in which the bristles are planted, to clean dirt in the mouth.

[0014] (3) The three-dimensional structure may also include rib-like portions extending away from the central axis, and these rib-like portions may be fixed to the beam-like portion. Furthermore, each of the multiple beam-like sections may have a flat plate shape perpendicular to each of the multiple beam-like sections and a rib-like section fixed to each of them, and each of the rib-like sections may constitute an inner wall of each of the voids in the width direction, which is perpendicular to the length direction when viewed in the thickness direction.

[0015] In other words, since the rib-shaped portion is fixed to the beam-shaped portion, the rib-shaped portion reinforces the beam-shaped portion, thereby receiving a portion of the force applied to the beam-shaped portion when the toothbrush of the present invention is used, strengthening the three-dimensional structure and reducing deformation of the handle portion.

[0016] (4) The beam-like portion may also have multiple sections.

[0017] In other words, in the toothbrush of the present invention, the force applied when trying to bend the handle in the bulging direction is distributed to each beam-like section, making deformation less likely when moving it in the vertical direction, which is the direction in which the bristles are planted.

[0018] (5) The rib-like portion may also be formed in the shape of a flat plate, with its surface direction coinciding with the direction of the handle portion's bulge.

[0019] In other words, since the rib-shaped portion is fixed to the beam-shaped portion and formed as a flat plate with a surface in the direction of handle bulging, it can be reinforced to make bending in the direction of handle bulging less likely to occur relative to the beam-shaped portion. Furthermore, the rib-shaped portion can be reinforced to make twisting of the beam-shaped portion less likely to occur around the central axis of the toothbrush as the center of rotation. As a result, deformation of the three-dimensional structure can be reduced.

[0020] Furthermore, since the rib-like portion is formed in a flat shape, the rib-like portion has an edge located far from the central axis of the toothbrush. The rib-like portion constitutes part of the three-dimensional structure, and the edge can be exposed to the outside of the three-dimensional structure. As a result, when the user grasps the three-dimensional structure with their fingers, or with their fingers and palm, they can touch this edge and grip the handle more easily.

[0021] (6) The three-dimensional structure may also include a grid structure which is configured to be substantially grid-like when viewed in the direction of the handle portion bulging. Alternatively, the three-dimensional structure may include a lattice structure in which the beam-like portions and rib-like portions are arranged in a substantially grid pattern when viewed in the thickness direction.

[0022] That is, since it is formed in a lattice shape when viewed in the bulging direction of the handle part, even when a force in a direction orthogonal to the bristle implantation direction is applied to the toothbrush of the present invention, the force is easily dispersed by the lattice structure that spreads in that direction. Therefore, the toothbrush of the present invention is particularly difficult to bend in the above-mentioned orthogonal direction, and even when the head part is moved in the left-right direction, which is one direction in the above-mentioned orthogonal direction, in order to clean the dirt in the oral cavity, deformation is unlikely to occur.

[0023] Also, at the ends of the lattice structure in the bulging direction of the handle part, the fingers and palm abut against the substantially lattice-shaped handle part. Therefore, since the fingers and palm of the user touch the substantially lattice-shaped surface, the user can hold the toothbrush of the present invention without feeling the stickiness felt when touching a smooth surface.

[0024] (7) Further, the handle part may have a pair of outer frame parts extending in a bifurcated manner away from the head part, and the rib-shaped part may be fixed to each of the outer frame parts. Furthermore, the outer frame portion may define the outer edge of the three-dimensional structure in the width direction.

[0025] That is, since the rib-shaped part is fixed to the outer frame part, the position and orientation of the rib-shaped part with respect to the entire toothbrush are stable during use. As a result, the position and orientation of the beam-shaped part fixed to the rib-shaped part with respect to the entire toothbrush are also stable, and deformation of the three-dimensional structure is less likely to occur.

[0026] (8) Further, the total volume of the respective voids may be in the range of 30% or more and less than 60% with respect to the combined volume of the volume of the head part and the total volume of the handle part including all the voids.

[0027] The inventor has found that when the porosity, which is the ratio of the total volume of the respective voids to the combined volume of the volume of the head part and the total volume of the handle part including all the voids, is less than 30%, the weight of the entire toothbrush is such that the user cannot sufficiently feel the effect of weight reduction during use. Also, when the porosity is 60% or more, it has been found that the strength of the entire toothbrush is insufficient for the user's use.

[0028] Therefore, the toothbrush of the present invention, having a void ratio of 30% or more and less than 60%, can be made lighter by reducing the amount of material filling relative to the total volume of the handle, and moreover, it can have sufficient strength to withstand use by the user even with a reduced amount of filling.

[0029] (9) The three-dimensional structure may also have a finger grip portion that is recessed inward in the direction of the handle portion's bulge, so that a part of the fingers that grip the handle portion can grip it. Alternatively, the three-dimensional structure may have a finger grip portion that is recessed inward in the thickness direction, so that a part of the fingers gripping the handle portion can be placed on it.

[0030] In other words, because the three-dimensional structure has a finger grip, the user can freely move the toothbrush of the present invention using their fingers. As a result, the toothbrush of the present invention is less prone to deformation during use and can be moved freely in all directions (left, right, forward, backward, up, and down), making it easy to clean plaque from inside the mouth. [Effects of the Invention]

[0031] Thus, the present invention provides a toothbrush that reduces the amount of material used to fill the handle portion relative to its overall volume, while being less prone to deformation when moved left, right, forward, backward, up, and down, and also has excellent water drainage. Furthermore, when synthetic resin is used as the material for the handle portion, the amount of synthetic resin used can be reduced, providing a toothbrush with a low burden on the global environment.

[0032] Furthermore, it is possible to provide a toothbrush that allows the user to easily grip the handle portion while reducing the amount of material filling the handle portion. [Brief explanation of the drawing]

[0033] [Figure 1] (a) A plan view of a toothbrush according to the first embodiment of the present invention. (b) A cross-sectional view of the toothbrush in Figure 1(a). (c) A left side view of the toothbrush in Figure 1(a). [Figure 2](a) A plan view of a toothbrush without gaps. (b) A cross-sectional view of the toothbrush in Figure 2(a). (c) A left side view of the toothbrush in Figure 2(a). [Figure 3] (a) Represents an enlarged plan view of the toothbrush in Figure 1. (b) Represents the cross-sectional view indicated by line BB in Figure 3(a). (c) Similarly, represents the cross-sectional view indicated by line AA. [Figure 4] (a)(b) Photographs showing the user holding the toothbrush shown in Figure 1. [Figure 5] (a)(b) Photographs showing the user holding the toothbrush shown in Figure 1. [Figure 6] (a)(b) These figures show a perspective view of the toothbrush in Figure 1, seen from a diagonal front angle. [Figure 7] (a)(b) These figures show a perspective view of the toothbrush in Figure 1, seen from diagonally behind. [Figure 8] (a) A plan view of the blank of Comparative Example 1. (b) A left side view of the blank of Comparative Example 1. [Figure 9] (a) A plan view of the blank of Comparative Example 2. (b) A left side view of the blank of Comparative Example 2. [Figure 10] A table showing the porosity in the examples and comparative examples is provided. [Figure 11] (a) A plan view of a toothbrush according to a second embodiment of the present invention. (b) A left side view of the toothbrush in Figure 11(a). [Figure 12] (a) A plan view of a toothbrush according to a third embodiment of the present invention. (b) A left side view of the toothbrush in Figure 12(a). [Figure 13] (a) Represents an enlarged plan view of the toothbrush in Figure 12. (b) Represents the cross-sectional view indicated by the DD line in Figure 13(a). (c) Similarly, represents the cross-sectional view indicated by the CC line. [Figure 14] (a) A plan view of a toothbrush according to the fourth embodiment of the present invention. (b) A left side view of the toothbrush of Figure 14(a). [Figure 15](a) A plan view of a toothbrush according to the fifth embodiment of the present invention. (b) A cross-sectional view of the toothbrush in Figure 15(a). (c) A left side view of the toothbrush in Figure 15(a). [Modes for carrying out the invention]

[0034] [First Embodiment] A first embodiment of the present invention will be described using Figures 1 to 10. In Figures 1(a) and 1(c), 11 is a toothbrush. In each figure, the direction of arrow U indicates the upward direction of the toothbrush 11 in the vertical direction, and the direction of arrow D indicates the downward direction. The direction of arrow L indicates the left side of the toothbrush 11 in the horizontal direction, and the direction of arrow R indicates the right side. Also, the direction of arrow F indicates the front of the toothbrush 11 in the front-to-back direction, and the direction of arrow B indicates the rear. Figure 1(a) shows a plan view of the toothbrush 11, and Figure 1(c) shows a left side view of the toothbrush 11.

[0035] The toothbrush 11 has a head portion 12 at its front end and a handle portion 13 behind the head portion 12. Multiple bristles 12a are embedded vertically in the head portion 12 of the toothbrush 11. The handle portion 13 is grasped by the user's fingers or fingers and palm, guiding the head portion 12 into the user's oral cavity, where the bristles 12a clean the inside of the oral cavity. The head portion 12 and the handle portion 13 are made of synthetic resin such as polypropylene or saturated polyester, and are formed, for example, by injection molding.

[0036] The handle portion 13 has a pair of outer frame portions 14 that extend backward from the head portion 12 in a bifurcated manner. The outer frame portion 14 has a left outer frame portion 14a on the left side and a right outer frame portion 14b on the right side. It also has a middle outer frame portion 14c, which is the base where the left and right outer frame portions 14a and 14b split into two.

[0037] The handle portion 13 has a three-dimensional structure 13a that bulges in the vertical direction. The three-dimensional structure 13a includes multiple beam-shaped portions 15 formed in the front-to-back direction and multiple rib-shaped portions 16 formed in the vertical and horizontal directions. That is, the beam-shaped portions 15 are formed in approximately the same direction as the central axis of the toothbrush 11, which is the axis that passes through the center of the cross-section of the toothbrush 11 in the front-to-back direction. The rib-shaped portions 16 are formed to extend away from the central axis of the toothbrush 11. In this embodiment, the three-dimensional structure refers to a structure in which, as shown in the left side view of Figure 1(c), the outer frame portion 14 has approximately the same thickness as the head portion 12 in the vertical direction, while the beam-shaped portions 15 and rib-shaped portions 16 bulge in the vertical direction more than the outer frame portion 14. Figure 1(b) shows cross-sectional views of each rib-shaped portion 16 at each position in the front-to-back direction.

[0038] Furthermore, the three-dimensional structure 13a of the handle portion 13 has multiple voids 13b that penetrate in the vertical direction, as shown in the plan view of Figure 1(a). For the sake of explanation, an example of a toothbrush without voids is shown in Figure 2. Figure 2(1) is a toothbrush without voids. Figure 2(a) shows a plan view of toothbrush 1. Figure 2(b) shows cross-sectional views of toothbrush 1 at various positions in the front-rear direction. In each cross-sectional view, the bottom of the figure indicates the top of toothbrush 1, and the top of the figure indicates the bottom of toothbrush 1. Figure 2(c) shows a left side view of toothbrush 1. In contrast to such a toothbrush 1 without voids, the toothbrush 11 of the present invention has multiple voids 13b as described above.

[0039] Each void 13b is composed of a space enclosed by the outer frame portion 14, each beam-like portion 15, and each rib-like portion 16.

[0040] The beam-like section 15 includes a left beam-like section 15a extending in the front-rear direction in the left half of the three-dimensional structure 13a, a right beam-like section 15b extending in the front-rear direction in the right half, and a middle beam-like section 15c extending in the front-rear direction at the foremost part of the three-dimensional structure 13a. The left and right beam-like sections 15a and 15b are arranged substantially parallel to each other in a plan view. The rear ends of the left and right beam-like sections 15a and 15b are fixed to the rear end of the left outer frame section 14a and the rear end of the right outer frame section 14b, respectively. The front end of the middle beam-like section 15c is fixed to the middle outer frame section 14c.

[0041] Furthermore, each beam-like section 15a, 15b, and 15c is fixed to the respective intersecting rib-like section 16. The left and right beam-like sections 15a and 15b, as a pair, are fixed to the rib-like sections 16 in each row. The central beam-like section 15c is fixed independently to the frontmost rib-like section 16 shown in Figure 1(a).

[0042] The cross-sections of the left and right beam-like sections 15a and 15b are shown in Figure 3(c). Figure 3(a) shows a magnified plan view of the central portion of the handle section 13 in the front-rear direction. Figure 3(c) shows a cross-sectional view of the three-dimensional structure 13a, with the viewing direction specified by the indicator line AA in Figure 3(a). In addition to the cross-sections of the left and right beam-like sections 15a and 15b, Figure 3(c) also shows the cross-sections of the left and right outer frame sections 14a and 14b, as well as the rib-like section 16a in the rear row of Figure 3(a).

[0043] The left and right beam-like sections 15a and 15b are formed such that their cross-sections are roughly rectangular, with the middle portion of the longitudinal direction slightly bulging laterally and elongated vertically. Although not shown in Figure 3, the central beam-like section 15c is also formed such that its cross-section is roughly rectangular and elongated vertically.

[0044] Each rib-shaped portion 16 is formed in a flat plate shape, such as the rib-shaped portion 16b in the front row of Figure 3(a), where the surface direction coincides with the vertical and horizontal directions. Figure 3(b) shows a cross-sectional view of the three-dimensional structure 13a, with the viewing direction specified by the indicator line BB in Figure 3(a), that is, a cross-sectional view of the rib-shaped portion 16b in the front row of Figure 3(a).

[0045] As shown in Figure 3(c), each rib-shaped portion 16 is fixed to the left outer frame portion 14a at its left corner and to the right outer frame portion 14b at its right corner.

[0046] Each beam-like section 15a, 15b, 15c and each rib-like section 16 are approximately orthogonal in a plan view, forming a three-dimensional structure 13a that forms a roughly grid structure in a plan view. In addition, each left and right outer frame section 14a, 14b also form a three-dimensional structure 13a that forms a roughly grid structure in a plan view between each beam-like section 15a, 15b, 15c and each rib-like section 16.

[0047] As shown in Figure 1(c), the three-dimensional structure 13a curves downward inward at the finger grip portion 17. This allows a portion of the fingers gripping the handle portion 13 to rest on the finger grip portion 17.

[0048] Figures 4(a) and 4(b) show the user holding the toothbrush 11 in a palm grip. Figures 5(a) and 5(b) show the user holding the toothbrush 11 in a pen grip, similar to how one would hold a pencil. In both cases, the images show how the user holds the toothbrush 11 when cleaning their teeth, with their thumb resting on the finger rest 17 as an example.

[0049] Figures 6(a) and 6(b) show the toothbrush 11 viewed from the front at an oblique angle. Figure 6(a) shows the top and left sides of each beam-like section 15a, 15b, and 15c, as well as the top and front of each rib-like section 16. Figure 6(b) shows the bottom and right sides of each beam-like section 15a, 15b, and 15c, as well as the bottom and front of each rib-like section 16.

[0050] Figures 7(a) and 7(b) show the toothbrush 11 viewed from a diagonal rearward angle. Figure 7(a) shows the top and right sides of each beam-like section 15a, 15b, and 15c, as well as the top and back sides of each rib-like section 16. Figure 7(b) shows the bottom and left sides of each beam-like section 15a, 15b, and 15c, as well as the bottom and back sides of each rib-like section 16.

[0051] With the above configuration, the toothbrush 11 has a handle portion 13 that has multiple voids 13b, and therefore requires less material filling compared to a toothbrush without voids, such as toothbrush 1 in Figure 2, thus making it lighter. Furthermore, despite the handle portion 13 having multiple voids 13b, it forms a three-dimensional structure 13a that bulges in the vertical direction, which is the direction of bulging of the handle portion 13. As a result, the user can easily grasp the handle portion 13 by grasping this three-dimensional structure 13a with their fingers, or with their fingers and palm. Figures 4 and 5 show the state in which the user easily holds the toothbrush 11 by grasping the three-dimensional structure 13a.

[0052] Furthermore, because the handle portion 13 has multiple voids 13b, even though the amount of material filling relative to the total volume is low, its three-dimensional structure 13 a This reinforces the overall strength of the toothbrush 11, making it less prone to deformation due to bending or twisting in any direction.

[0053] Furthermore, since multiple voids 13b penetrate the handle portion 13, less saliva, moisture, etc. accumulates in these voids 13b during brushing, resulting in good drainage.

[0054] Because the cross-sections of each beam-like section 15a, 15b, and 15c are elongated vertically, the second moment of area of ​​each beam-like section 15a, 15b, and 15c is large when bending them vertically. As a result, the bending stiffness (bending rigidity) of each beam-like section 15a, 15b, and 15c is large when bending them vertically. Therefore, the toothbrush 11 is particularly resistant to bending vertically, and deformation is less likely to occur when moving it vertically, which is the direction in which the bristles of the brush 12a are planted, to clean dirt in the oral cavity.

[0055] Since the toothbrush 11 has multiple beam-like sections 15, the force applied when trying to bend it in the vertical direction is distributed among the beam-like sections 15a, 15b, and 15c, making it less prone to deformation when moved in the vertical direction.

[0056] Since the rib-shaped portion 16 is fixed to each beam-shaped portion 15a, 15b, and 15c, the rib-shaped portion 16 reinforces each beam-shaped portion 15a, 15b, and 15c, thereby receiving a portion of the force applied to each beam-shaped portion 15a, 15b, and 15c when the toothbrush 11 is used, thus forming the three-dimensional structure 13 a This strengthens the structure and reduces deformation of the handle portion 13.

[0057] Since the rib-shaped portion 16 is fixed to each beam-shaped portion 15a, 15b, and 15c and is formed as a flat plate with a surface in the vertical direction, it can reinforce each beam-shaped portion 15a, 15b, and 15c so that bending in the vertical direction is less likely to occur. In addition, the rib-shaped portion 16 can reinforce each beam-shaped portion 15a, 15b, and 15c so that twisting around the central axis of the toothbrush is less likely to occur. As a result, deformation of the three-dimensional structure 13a can be reduced.

[0058] Furthermore, since the rib-shaped portion 16 is formed in a flat shape, the rib-shaped portion 16 has its edge located far from the central axis of the toothbrush 11. The rib-shaped portion 16 constitutes part of the three-dimensional structure 13a, and the edge can be exposed to the outside of the three-dimensional structure 13a. As a result, when the user grasps the three-dimensional structure 13a with their fingers, or with their fingers and palm, they can touch this edge and grip the handle portion 13 more easily.

[0059] Because it is formed in a grid pattern in plan view, the toothbrush 11 easily distributes force when force is applied in the left-right or front-back direction due to its grid structure that expands in that direction. Therefore, the toothbrush 11 is less likely to bend in the left-right or front-back direction, and deformation is less likely to occur when the head portion 13 is moved from side to side to clean dirt in the oral cavity.

[0060] Furthermore, at the vertical ends of the grid structure, the fingers and palm come into contact with the roughly grid-like handle portion 13. As a result, the user can grip the toothbrush 11 without feeling the stickiness that would be felt with a smooth surface, because their fingers and palm are in contact with the roughly grid-like surface.

[0061] Since the rib-shaped portion 16 is fixed to the outer frame portion 14, the position and orientation of the rib-shaped portion 16 relative to the entire toothbrush 11 is stable during use. As a result, the position and orientation of each beam-shaped portion 15a, 15b, and 15c fixed to the rib-shaped portion 16 relative to the entire toothbrush 11 are also stable, making deformation of the three-dimensional structure 13a less likely.

[0062] Because the three-dimensional structure 13a has a finger grip portion 17, the user can freely move the toothbrush 11 using their fingers. As a result, the toothbrush 11 is less likely to deform during operation and can be moved freely in all directions (left, right, forward, backward, up, and down), making it easy to clean plaque from inside the mouth.

[0063] [Examples] As an embodiment of this model, the inventor manufactured a toothbrush 11 as shown in Figures 1 and 3-7, in a state before the bristles 12a were attached. This toothbrush in this state before the bristles were attached is called a blank. The inventor then measured the volume of each void 13b in the blank in this embodiment, and divided the sum of the volumes of each void 13b by the volume of a blank without voids as shown in Figure 2, that is, by the sum of the volume of the head portion 12 and the total volume of the handle portion 13 including each void 13b, the result was 0.530. The value obtained by dividing the sum of the volumes of each void by the volume of the head portion and the total volume of the handle portion including all voids is called the void ratio and is expressed as a percentage (%). Therefore, the void ratio in this embodiment was 53.0%.

[0064] In contrast, a blank shown in Figures 8(a) and 8(b) was manufactured as Comparative Example 1. Figure 8(a) shows a plan view of the blank of Comparative Example 1, and Figure 8(b) shows a left side view of the blank. In Comparative Example 1, compared to the example, no void was provided in the portion corresponding to the area from the rib-like portion 16 up to the third row from the rear in the example to the rear end of the blank, and a blank with a shape that does not have a void in that portion was manufactured, similar to Figure 2. The void ratio in Comparative Example 1 was 29.0%.

[0065] Furthermore, a blank shown in Figures 9(a) and 9(b) was fabricated as Comparative Example 2. Figure 9(a) shows a plan view of the blank of Comparative Example 2, and Figure 9(b) shows a left side view of the blank. In Comparative Example 2, compared to the example, a blank was fabricated with the left and right beam-like portions 15a and 15b in the 1st to 3rd rows from the rear in the example, and the rib-like portions 16 in the 1st to 3rd rows from the rear in the example, removed. The void ratio in this Comparative Example 2 was 63.6%. The void ratios for these examples and each comparative example are shown in the table in Figure 10.

[0066] The inventor then fabricated a blank for Comparative Example 1 and found that when the porosity was less than 30%, as in Comparative Example 1, the overall weight of the toothbrush 11 was such that the user could not fully perceive the effect of its lightness. Furthermore, when fabricated a blank for Comparative Example 2, the inventor found that when the porosity was 60% or more, as in Comparative Example 2, the overall strength of the toothbrush 11 was insufficient for the user's use.

[0067] Therefore, by having a void ratio of 30% or more and less than 60%, the toothbrush 11 can fully achieve a weight reduction effect by reducing the amount of material filling relative to the total volume of the handle portion 13, and moreover, it can have sufficient strength to withstand use by the user even with a reduced amount of filling. Thus, it is preferable that the void ratio of the toothbrush 11 of the present invention is in the range of 30% or more and less than 60%.

[0068] [Second Embodiment] A second embodiment of the present invention will be described with reference to Figure 11. The toothbrush 21 shown in Figure 11 has a head portion 22, bristles 22a planted on the head portion 22, and a handle portion 23. The handle portion 23 has left and right outer frame portions 24a and 24b that extend backward from the head portion 22 in a bifurcated manner, and an inner outer frame portion 24c which is the base portion where these left and right outer frame portions 24a and 24b split into two. The handle portion 23 also has a three-dimensional structure 23a that bulges in the vertical direction.

[0069] The three-dimensional structure 23a includes multiple beam-like sections 25 formed in the front-to-back direction and multiple rib-like sections 26 formed in the vertical and horizontal directions. The three-dimensional structure 23a also has multiple voids 23b that penetrate in the vertical direction, as shown in the plan view of Figure 11(a). In Figure 11(a), only some of the voids 23b are labeled, but each rectangular-looking space is formed within the void 23b. Part of the voids 23b is composed of spaces enclosed by the outer frame sections 24a, 24b, 24c, each beam-like section 25, and each rib-like section 26. Another part of the voids 23b is drilled in the inner outer frame section 24c, arranged in a row in the front-to-back direction.

[0070] The beam-like section 25 includes a pair of left and right beam-like sections 25a and 25b extending in the front-rear direction. The front ends of each beam-like section 25a, 25b are fixed to a rib-like section 26 that surrounds the third gap 23b from the front from the rear. The rear ends of each beam-like section 25a, 25b are fixed to the left and right outer frame sections 24a, 24b. In addition, each beam-like section 25a, 25b is fixed to the respective intersecting rib-like sections 26.

[0071] Each rib-shaped portion 26 is formed in a flat plate shape with its surface direction coinciding with the vertical and horizontal directions. The vertical length of each rib-shaped portion 26 is greater than the vertical length of each beam-shaped portion 25a, 25b at the point where they intersect, and is configured to appear to protrude upward from the edges of each beam-shaped portion 25a, 25b in the side view shown in Figure 11(b). In addition, the left and right corners of each rib-shaped portion 26 are fixed to the left and right outer frame portions 24a, 24b, respectively.

[0072] Each beam-like portion 25a, 25b and each rib-like portion 26 are approximately perpendicular in a plan view, forming a three-dimensional structure 23a that forms a roughly grid structure in a plan view. In addition, each outer frame portion 24a, 24b, 24c also forms a three-dimensional structure 23a that forms a roughly grid structure in a plan view between each beam-like portion 25a, 25b and each rib-like portion 26.

[0073] The three-dimensional structure 23a is curved so as to be recessed downward at the finger grip portion 27, as shown in the left side view of Figure 11(b).

[0074] The other components are the same as those of the first embodiment.

[0075] [Third Embodiment] A third embodiment of the present invention will be described with reference to Figures 12 and 13. The toothbrush 31 shown in Figure 12 has a head portion 32, a brush 32a planted on the head portion 32, and a handle portion 33. The handle portion 33 has left and right outer frame portions 34a and 34b that extend backward in a bifurcated manner from the head portion 32, and an inner outer frame portion 34c which is the base portion where these left and right outer frame portions 34a and 34b split into two. The handle portion 33 also has a three-dimensional structure 33a that bulges in the vertical direction.

[0076] The three-dimensional structure 33a includes multiple beam-like sections 35 formed in the front-to-back direction, and multiple pairs of left and right rib-like sections 38, 39 formed in the up-down and left-to-right directions, respectively. The three-dimensional structure 33a also has multiple voids 33b that penetrate in the up-to-down direction, as shown in the plan view of Figure 12(a). In Figure 12(a), only some of the voids 33b are labeled, but each rectangular or triangular space is formed in the void 33b. The voids 33b are composed of spaces enclosed by the outer frame sections 34a, 34b, 34c, each beam-like section 35, and each rib-like section 38, 39.

[0077] The beam-like section 35 includes a pair of left and right beam-like sections 35a and 35b that extend in the front-rear direction. The front ends of each beam-like section 35a and 35b are fixed to the inner outer frame section 34c. The rear ends of each beam-like section 35a and 35b are fixed to the left and right outer frame sections 34a and 34b. In addition, the left beam-like section 35a is fixed to each left rib-like section 38, which are the rib-like sections on the left side, and the right beam-like section 35b is fixed to each right rib-like section 39, which are the rib-like sections on the right side.

[0078] The cross-sections of the left and right beam-like sections 35a and 35b are shown in Figure 13(c). Figure 13(a) shows a magnified plan view of the central portion of the handle section 33 in the front-rear direction. Figure 13(c) shows a cross-sectional view of the three-dimensional structure 33a, with the viewing direction specified by the indicator line CC in Figure 13(a). In addition to the cross-sections of the left and right beam-like sections 35a and 35b, Figure 13(c) also shows the cross-sections of the left and right outer frame sections 34a and 34b, as well as the left rib-like section 38a and the right rib-like section 39a in the rear row of Figure 13(a).

[0079] The left and right rib-like portions 38 and 39 are formed in a flat plate shape, such as the rib-like portions 38b and 39b in the front row of Figure 13(a), with their surface directions coinciding with the vertical and horizontal directions. The left and right rib-like portions 38 and 39 extend to the left and right, respectively, away from the central axis of the toothbrush 31. Furthermore, the left and right beam-like portions 35a and 35b and the left and right rib-like portions 38 and 39 are connected as follows: flat They are approximately orthogonal in a surface view. Figure 13(b) shows a cross-sectional view of the three-dimensional structure 33a, with the viewing direction specified by the indicator line DD in Figure 13(a), that is, it shows the cross-sectional views of the left rib-like portion 38b and the right rib-like portion 39b in the front row of Figure 13(a).

[0080] As shown in Figure 13(c), the left rib-shaped portion 38 is fixed to the left outer frame portion 34a at its left corner and to the left beam-shaped portion 35a at its right end. Similarly, the right rib-shaped portion 39 is fixed to the right beam-shaped portion 35b at its left end and to the right outer frame portion 34b at its right corner.

[0081] Each beam-like portion 35a, 35b, each rib-like portion 38, 39, and each left and right outer frame portion 34a, 34b constitute a three-dimensional structure 33a such that each gap 33b forms a substantially grid structure in plan view.

[0082] The three-dimensional structure 33a is curved so as to be recessed downward at the finger grip portion 37, as shown in the left side view of Figure 12(b).

[0083] The other components are the same as those of the first embodiment.

[0084] [Fourth Embodiment] A fourth embodiment of the present invention will be described with reference to Figure 14. The toothbrush 41 shown in Figure 14 has a head portion 42, a brush 42a planted on the head portion 42, and a handle portion 43. The handle portion 43 has left and right outer frame portions 44a, 44b that extend backward in a bifurcated manner from the head portion 42, and an inner outer frame portion 44c which is the base portion where these left and right outer frame portions 44a, 44b split into two. The handle portion 43 also has a three-dimensional structure 43a that bulges in the vertical direction.

[0085] The three-dimensional structure 43a includes multiple beam-like sections 45 formed in the front-to-back direction and multiple pairs of left and right rib-like sections 48, 49 formed in the left-to-right direction. The three-dimensional structure 43a also has multiple voids 43b that penetrate in the vertical direction, as shown in the plan view of Figure 14(a). In Figure 14(a), only some of the voids 43b are labeled, but each rectangular or triangular space is formed in the void 43b. The voids 43b are composed of spaces enclosed by the outer frame sections 44a, 44b, 44c, each beam-like section 45, and each rib-like section 48, 49.

[0086] The beam-like section 45 includes a pair of left and right beam-like sections 45a and 45b that extend in the front-rear direction. The front ends of each beam-like section 45a and 45b are fixed to the inner outer frame section 44c. The rear ends of each beam-like section 45a and 45b are fixed to the left and right outer frame sections 44a and 44b. In addition, the left beam-like section 45a is fixed to the right end edge of each left rib-like section 48, which is the left rib-like section, and the right beam-like section 45b is fixed to the left end edge of each right rib-like section 49, which is the right rib-like section.

[0087] Each rib-like portion 48, 49 is formed in a flat plate shape with its surface direction coinciding with the front-to-back and left-to-right directions, as shown by the hidden lines in the plan view of Figure 14(a) and the left side view of Figure 14(b). Furthermore, the left and right rib-like portions 48, 49 extend to the left and right, respectively, away from the central axis of the toothbrush 41. In addition, the left edge of each left rib-like portion 48 is fixed to the left outer frame portion 44a, and the right edge of each right rib-like portion 49 is fixed to the right outer frame portion 44b.

[0088] Each beam-like section 45a, 45b, each rib-like section 48, 49, and each left and right outer frame section 44a, 44b constitute a three-dimensional structure 43a such that each gap 43b forms a roughly grid structure in plan view.

[0089] The three-dimensional structure 43a is curved so as to be recessed downward at the finger grip portion 47, as shown in the left side view of Figure 14(b).

[0090] Other configurations are the same as those of the first and third embodiments.

[0091] [Fifth Embodiment] A fifth embodiment of the present invention will be described with reference to Figure 15. The toothbrush 51 shown in Figure 15 has a head portion 52, a brush 52a planted on the head portion 52, and a handle portion 53. The handle portion 53 has left and right outer frame portions 54a, 54b that extend backward in a bifurcated manner from the head portion 52, and an inner outer frame portion 54c which is the base portion where these left and right outer frame portions 54a, 54b split into two. The handle portion 53 also has a three-dimensional structure 53a that bulges in the vertical direction.

[0092] The three-dimensional structure 53a includes a beam-like portion 55 formed in the front-to-back direction and a plurality of rib-like portions 56 formed in the vertical and horizontal directions, respectively. The three-dimensional structure 53a also has a plurality of voids 53b that penetrate in the vertical direction, as shown in the plan view of Figure 15(a). In Figure 15(a), only some of the voids 53b are labeled, but each rectangular or triangular space is formed in the void 53b. The voids 53b are composed of spaces enclosed by the outer frame portions 54a, 54b, 54c, the beam-like portion 55, and the rib-like portions 56.

[0093] The front end of the beam-like section 55 is fixed to the inner outer frame section 54c. The rear end of the beam-like section 55 is fixed to the left and right outer frame sections 54a and 54b at the point where they meet at their respective rear ends. Furthermore, the beam-like section 55 is fixed to each intersecting rib-like section 56.

[0094] Each rib-shaped portion 56 is formed in a flat plate shape with its surface direction coinciding with the vertical and horizontal directions. Figure 15(b) shows a cross-sectional view of each rib-shaped portion 56 at each position in the front-rear direction. In addition, the left and right corners of each rib-shaped portion 56 are fixed to the left and right outer frame portions 54a and 54b, respectively.

[0095] The beam-like portion 55 and each rib-like portion 56 are substantially perpendicular in a plan view, forming a three-dimensional structure 53a that forms a substantially grid structure in a plan view. The left and right outer frame portions 54a and 54b also form a three-dimensional structure 53a that forms a substantially grid structure in a plan view between the beam-like portion 55 and each rib-like portion 56.

[0096] The three-dimensional structure 53a is curved so as to be recessed downward at the finger grip portion 57, as shown in the left side view of Figure 15(b).

[0097] The other components are the same as those of the first embodiment.

[0098] Although embodiments of the present invention have been illustrated above, the present invention is not limited to these embodiments, and various modifications are possible without departing from the spirit of the invention.

[0099] For example, the number of beam-like sections is not limited to one or two; there may be three or more, as long as the thinning of each beam-like section does not impair the vertical bending rigidity, overall strength, etc.

[0100] Furthermore, the arrangement of each beam-like section does not necessarily have to be parallel to each other; it may be at an angle as long as it does not impair the overall bending rigidity, strength, etc.

[0101] The shape of each beam-like section and each rib-like section, or their arrangement, does not necessarily have to be symmetrical. They may be asymmetrical as long as the force applied during use and the deformation of the three-dimensional structure do not become extremely uneven.

[0102] The plate thickness in the left-right direction or the width in the up-down direction of each beam-like section does not necessarily have to be uniform in the front-to-back direction, and the plate thickness in the front-to-back direction of each rib-like section does not necessarily have to be uniform in the up-to-down direction or the left-to-right direction. These may be uneven as long as the force applied during use and the deformation of the three-dimensional structure do not vary extremely.

[0103] Each rib-like section does not need to be arranged with an even pitch in the front-to-back direction; the pitch may be uneven as long as the force applied during use and the deformation of the three-dimensional structure are not extremely distorted. Furthermore, the plane direction of each rib-like section does not necessarily have to coincide with the vertical direction; they may be arranged at an angle, for example, in the front-to-back, left-to-right directions, as long as the beam-like section is sufficiently reinforced. [Industrial applicability]

[0104] This invention can be used in toothbrushes for users to clean their teeth on a daily basis. [Explanation of Symbols]

[0105] 11, 21, 31, 41, 51 Toothbrushes 12, 22, 32, 42, 52 Head section 12a,22a,32a,42a,52a brush 13, 23, 33, 43, 53 Handle section 13a,23a,33a,43a,53a 3D structure 13b,23b,33b,43b,53b void 14a, 24a, 34a, 44a, 54a Left outer frame section (outer frame section) 14b, 24b, 34b, 44b, 54b Right outer frame section (outer frame section) 14c, 24c, 34c, 44c, 54c Inner and outer frame section (outer frame section) 15a,25a,35a,45a Left beam part (beam part) 15b,25b,35b,45b Right beam part (beam part) 55 Beam-like part 16, 26, 56 Rib-shaped section 17, 27, 37, 47, 57 Finger grips 38,48 Left rib-like section (rib-like section) 39,49 Right rib-like section (rib-like section)

Claims

1. A toothbrush having a head portion and a handle portion, wherein a brush is embedded in the head portion, the handle portion is grasped and the head portion is guided into the oral cavity, and the toothbrush is used to clean the dirt in the oral cavity, The handle portion has a three-dimensional structure that bulges in a direction parallel to the direction in which the bristles of the brush are planted, and has a pair of outer frame portions that extend in a bifurcated manner away from the head portion. The three-dimensional structure has a plurality of voids penetrating in the thickness direction, which is the direction in which the handle portion bulges, and a plurality of beam-like portions, and the outer edge in the width direction, which is perpendicular to the length direction, which is approximately the axis of the toothbrush's center when viewed in the thickness direction, is defined by the outer frame portion. Each of the beam-like portions has a beam-like shape extending in the longitudinal direction and a vertically elongated cross-section whose longitudinal direction coincides with the thickness direction, forming the inner wall of each void in the longitudinal direction, and the cross-sections are substantially parallel to each other. A toothbrush characterized by the following features.

2. Multiple plates, each having a flat plate shape perpendicular to each of the multiple beam-like sections, and each having a rib-like section fixed to it, Each of the rib-like portions constitutes the inner wall of each of the gaps in the width direction. The toothbrush according to feature 1.

3. The three-dimensional structure includes a lattice structure in which the beam-like portions and rib-like portions are arranged in a substantially lattice pattern when viewed in the thickness direction. The toothbrush according to feature 2.

4. The rib-shaped portion is fixed to each of the outer frame portions. The toothbrush according to feature 2.

5. The total volume of each of the aforementioned voids is between 30% and 60% of the combined volume of the head portion and the total volume of the handle portion including all of the aforementioned voids. A toothbrush according to any one of features 1 to 4.

6. The three-dimensional structure has a finger grip portion that is recessed inward in the thickness direction, so that a part of the fingers that grip the handle portion can grip it. A toothbrush according to any one of features 1 to 4.

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