Toothbrush and method for manufacturing a toothbrush

Abstract

To provide a toothbrush in which moisture easy to stay on bristles on a back face side of a head part is removed and cleanliness can be maintained, and a production method of the same.SOLUTION: A toothbrush (1) comprises: bristles (4a); and a head part (2) on which hair bundles (4) formed by bundling multiple bristles (4a) are implanted, wherein the head part (2) has an implantation surface (2a) and implantation holes (3) are opened on the implantation surface (2a), and the hair bundles (4) are folded in half, and with a folding back part being a portion folded in half positioned at the head in the two-folded state, the hair bundles are implanted in the implantation holes (3). The implantation holes (3) penetrate a back surface opposite to the implantation surface (2a) of the head part (2), and the hair bundle (4) is configured so that the folding back part (5) is exposed on an opening on the back surface side.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a toothbrush and a method for manufacturing a toothbrush, and more particularly to a toothbrush having implanting holes penetrating through a head portion and a method for manufacturing a toothbrush including a toothbrush preparation step of preparing a toothbrush having a head portion provided with the implanting holes penetrating therethrough.

Background Art

[0002] Conventionally, there is a toothbrush including bristles and a head portion for implanting a tuft of the plurality of bristles, the head portion having an implanting surface with implanting holes formed therein, the tuft being folded in two, and in the folded state, being implanted in the implanting holes with a folded-back portion, which is a portion to be folded in two, at the head. (Patent Document 1).

[0003] In a conventional toothbrush, the tuft of the plurality of bristles can be implanted in the head portion by folding the tuft in a U shape and driving a flat wire sandwiched therebetween into the implanting holes.

[0004] The flat wire is a thin plate such as a rectangular metal plate, is inserted from an entrance of the implanting holes, and the edges of two opposite sides thereof advance to the middle of the implanting holes so as to draw two axial grooves on an inner peripheral surface in the implanting holes. However, since the two grooves are narrow, even when the flat wire attempts to return in the reverse direction through the implanting holes, a frictional force in the axial direction of the implanting holes is generated between the edges of the two sides and the grooves. As a result, the bristles maintain the implanted state without being removed from the implanting holes.

[0005] Further, since the head portion has a certain thickness, the implanting holes having a depth corresponding to the thickness can be formed, and necessary friction can be generated by securing the length of the grooves.

[0006] According to these, the conventional toothbrush can securely fix the bristles to the head portion while adopting a simple assembling method of driving the flat wire and the tuft into the implanting holes. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2016-63912 [Overview of the project] [Problems that the invention aims to solve]

[0008] Conventional toothbrushes have bristle holes with a bottom surface, and therefore, these bristle holes are closed on the back side of the head portion opposite to the bristle surface. Due to this configuration, the bristles are not exposed on the back side of the head portion.

[0009] In contrast, when a toothbrush is used to clean the inside of the mouth, such as teeth and gums, moisture such as the user's saliva and cleaning solutions can accumulate at the bottom of the bristle holes via the bristles. Moisture such as running water or cleaning water used to wash the toothbrush may also accumulate. Because the bristle bundles are fitted into the bristle holes, it is difficult for this moisture to be discharged by flowing back up through the bristle holes. Furthermore, because these bristles at the bottom are housed inside the blocked bristle holes, they cannot be easily dried with air, gas, or other gases, nor can they be wiped with absorbent materials such as cloth, cotton, or paper.

[0010] As a result, the accumulation of moisture makes it easy for bacteria to multiply, making it difficult to keep the toothbrush clean.

[0011] In view of these problems, the present invention aims to provide a toothbrush that can remove moisture that tends to accumulate on the bristles on the back of the head and keep it clean, and to provide a method for manufacturing such a toothbrush. [Means for solving the problem]

[0012] (1) The present invention provides a toothbrush comprising a brush and a head portion for implanting a bundle of bristles formed by bundling a plurality of the brushes, wherein the head portion has a bristle surface and bristle holes are made on the bristle surface, the bristle bundle is folded in half, and in this folded state, the folded portion is implanted in the bristle holes with the folded part being the leading edge, wherein the bristle holes penetrate the back surface of the head portion opposite to the bristle surface, and the bristle bundle has the folded part exposed at the opening on the back side. Furthermore, the bundle of hair has the folded portion on the back It is exposed at the side opening, and part or all of the folded portion is separated from the head portion. The protruding, folded portion is radially outward more than the straight portion that is continuous with the flocked surface side. It doesn't need to spread.

[0013] In other words, in the toothbrush of the present invention, the folded portion of the bristles is exposed at the opening on the back side. Therefore, when using the toothbrush to clean the inside of the mouth, and when washing, moisture such as saliva, medication, running water, or washing water can be wiped off by applying an absorbent material such as cloth, cotton, or paper to the exposed bristles. By removing moisture in this way, the toothbrush can be kept clean.

[0014] Furthermore, when the hair bundle comes into contact with the inner wall of the hair implantation hole, the folded portion where the hair bundle makes a U-turn does not come into contact with the inner wall, whereas the hair bundle comes into contact with the inner wall at the straight portion, which is a roughly columnar bundle that is continuous with the hair implantation surface side of the folded portion. Even if an external force causes the hair bundle to attempt to exit the hair implantation hole in the opposite direction, a frictional force is generated between the hair bundle and the inner wall in the axial direction of the hair implantation hole at this straight portion, causing the hair bundle to remain in place.

[0015] Therefore, because the toothbrush of the present invention is configured such that the folded portion is exposed on the back side, the area in contact with the inner wall of the straight portion is larger compared to toothbrushes in which this portion is not exposed. Furthermore, even if the plate thickness of the head portion is made smaller, the frictional force is large, and the bristle bundles can be securely kept in their planted positions. And because the bristle bundles remain in their planted positions, the absorbent material can be applied to the exposed bristle bundles at all times, keeping the toothbrush clean. Moreover, it reduces the likelihood of the bristles falling out of the planted holes, allowing the toothbrush to be used for a long time.

[0016] Incidentally, it is known that by reducing the thickness of the toothbrush head, the toothbrush can reach the back teeth more easily and clean the inside of the mouth more effectively. Therefore, the toothbrush of the present invention makes it easier to clean the inside of the mouth and can be used for a long time.

[0017] (2) The hair bundle may also have a flat wire that is driven into the hair implantation hole, and the hair bundle may be folded in half by the flat wire and pushed into the hair implantation hole.

[0018] In other words, the flat wire is inserted from the entrance of the bristle-planting hole, and its two opposing edges move through the bristle-planting hole, creating two axial grooves on the inner circumferential surface. However, because the two grooves are shallow and narrow, even if the flat wire tries to return to the bristle-planting hole in the opposite direction, a frictional force is generated between the two edges and the grooves in the axial direction of the bristle-planting hole. As a result, the brush remains planted without falling out of the bristle-planting hole.

[0019] At this time, for example, when there are two types of head parts with the same plate thickness, and the folded-back part is not exposed in one head part while the folded-back part is exposed in the other head part, the other head part can fold the hair bundle at a deeper position, and the depth at which the flat line can be inserted into the one head part is smaller than the depth of the other head part at the same position. Thus, since the toothbrush of the present invention is configured such that the folded-back part is exposed in the head part, the flat line can be pushed deeper, and the friction between the edges of the two sides and the groove is large.

[0020] As described above, by being able to make these frictions relatively large, even if the plate thickness of the head part is configured to be smaller, the toothbrush of the present invention can generate the required amount of friction.

[0021] And by reducing the plate thickness of the head part, the toothbrush can more easily reach the back teeth and is easier to clean inside the oral cavity. Therefore, with the toothbrush of the present invention, it is easy to clean the oral cavity and can be used for a long time.

[0022] (3) Also, the inner space of the hair implanting hole is formed in a substantially cylindrical shape, and the flat line is arranged such that the lower end of the flat line, which is one side on the back side, is located on the hair implanting surface side with respect to the virtual bottom surface of the hair implanting hole, which is the substantially cylindrical , located on the rear side virtual edge surface.

[0023] That is, by being configured such that one side of the flat line is located on the hair implanting surface side with respect to the virtual bottom surface of the hair implanting hole, the flat line does not protrude from the back side of the head part beyond the virtual bottom surface of the hair implanting hole. Therefore, it is possible to prevent an accident in which the flat line protrudes from the head part and damages the user's oral cavity.

[0024] In this way, the toothbrush of the present invention can be used for a long time and cleanly while preventing injury to the oral cavity by the flat line.

[0025] (4) Furthermore, the inner space of the hair implantation hole is formed in a substantially columnar shape, and the lower end of the flat wire, which is one side on the back side, is formed in a substantially columnar shape , located on the rear side virtuality edge The surface is inscribed within the virtual bottom surface of the hair implantation hole. ruyo It can also be installed in a uni (sea urchin) configuration.

[0026] In other words, by configuring the flat wire to be inscribed within the virtual base surface of the bristle implantation hole, the flat wire does not protrude beyond the back side of the head portion beyond the virtual base surface of the bristle implantation hole. Therefore, accidents that could injure the user's mouth due to the flat wire protruding from the head portion can be prevented.

[0027] At the same time, because the flat wire is inscribed within the virtual bottom surface of the bristle-planting hole, it can be positioned at the deepest location of the bristle-planting hole. As a result, the friction between the flat wire and the groove is greater, the straight section is longer, and the bristle bundle adheres more tightly to the inner wall. Therefore, even when the plate thickness of the head is small, the bristle bundle can remain more securely in place and will not fall out.

[0028] Thus, the toothbrush of the present invention can be used hygienically for a long time while preventing injuries to the oral cavity caused by flat bristles.

[0029] (5) The plate thickness of the head portion may also be formed to be in the range of 1.5 mm or more and less than 4.0 mm.

[0030] Even when the thickness of the head portion of the toothbrush of the present invention is reduced, the bristle bundles remain securely in place.

[0031] Traditionally, the thickness of the head portion of a thin toothbrush is said to be approximately 2.5 mm. Incidentally, regarding toothbrushes, according to the commentary on "Toothbrush JIS S 3016-1995," revised on March 1, 1995, by the Japanese Industrial Standards Committee (now the Japanese Industrial Standards Committee), the bristle-holding strength is stipulated to be "a maximum tensile force of 8 N or more," based on a resolution of the Japanese Industrial Standards Committee Standards Committee on June 1, 1990. Therefore, the inventor has found through experiments that, in the case of the toothbrush of the present invention, even if the thickness of the head portion is as thin as 1.5 mm, the bristle-holding strength exhibits a value of 15 N or more, which is greater than the above-mentioned stipulated value of 8 N. Furthermore, it has been found that even when the thickness of the head portion is 1.5 mm or more and less than 4.0 mm, it exhibits the above-mentioned value of 15 N or more. Furthermore, experiments also revealed that even when the plate thickness of the head section is 4.0 mm or more and 5.0 mm or less, the bristle-holding strength is reduced when some of the bristle-planting holes are small in diameter, but it still shows a value of 15 N or more as mentioned above.

[0032] Thus, the toothbrush of the present invention can have a head plate thickness set in the range of 1.5 mm or more and 5.0 mm or less, and also has a plate thickness of 1.5 mm or more and less than 4.0 mm, thereby having sufficient bristle-holding strength which is more desirable for a toothbrush.

[0033] (6) The bristles may also have a reduced diameter portion in which the inner diameter is smaller than the opening diameter of the bristles surface.

[0034] In other words, during bristle implantation, the bristle bundles are prevented from being unnecessarily pushed to the back side by the narrowed diameter of the bristle implantation hole. Therefore, the toothbrush of the present invention can be easily manufactured with the bristle bundles implanted at a predetermined depth. Furthermore, the bristle bundles do not come out to the back side during use, and the brush does not fall out of the bristle implantation hole, so this toothbrush can be used for a long time.

[0035] (7) In addition, the reduced diameter portion may have a virtual bottom surface of the reduced diameter portion which is a virtual back side end surface of the inner space and the virtual bottom surface of the hair flocking hole.

[0036] In other words, since the virtual bottom surface of the reduced diameter portion coincides with the virtual bottom surface of the hair implantation hole, the reduced diameter portion is positioned biased toward the back side of the hair implantation hole. Furthermore, because the depth to which the hair bundle is pushed in is restricted by the reduced diameter portion, the hair bundle is pushed in more deeply compared to when the reduced diameter portion is positioned closer to the hair implantation surface, and the contact area between the straight portion and the inner wall of the hair implantation hole is larger. As a result, the frictional force generated between the straight portion and the inner wall is large, and the risk of the hair bundle falling out from the hair implantation surface side is small.

[0037] Furthermore, because the flat wire can be inserted more deeply, the frictional force generated between the flat wire and the groove in the hair implantation hole is greater, preventing the flat wire that holds the hair bundle from returning to the hair implantation surface side. This also reduces the risk of the hair bundle falling out from the hair implantation surface side.

[0038] (8) The flat wire may also be arranged such that its lower end is tangent to the virtual upper surface of the reduced diameter portion, which is the virtual end surface on the flocked surface side of the inner space of the reduced diameter portion.

[0039] In other words, since the flat wire is tangent to the virtual upper surface of the reduced diameter portion, it does not penetrate any further into the reduced diameter portion and become fitted into it. Therefore, there is no need to apply greater pressure to fit the flat wire into the reduced diameter portion, where the inner diameter is smaller than the opening diameter of the bristle surface, and the toothbrush of the present invention can be easily manufactured.

[0040] (9) The hair follicle may also have an internal space formed in a substantially columnar shape, and the hair bundle may have the folded portion in contact with the virtual bottom surface of the hair follicle, which is the virtual back end surface of the substantially columnar shape. Furthermore, it comprises a brush and a head portion on which a bundle of bristles formed by bundling multiple brushes is implanted, and the head portion It has a bristle surface and bristle holes are made in the bristle surface, and the bristle bundle is folded in half, With the hair folded in half, the folded portion is placed at the front of the hair follicle. A toothbrush provided, wherein the bristle holes have an inner space formed in a substantially columnar shape and the The bristle bundle penetrates the back side opposite to the bristle surface of the head portion, and the folded portion is on the back side The folded portion is exposed at the opening, and the substantially columnar virtual rear side end The folded portion is inscribed within the virtual bottom surface of the flocked hole, which is a surface, and the folded portion is continuous with the flocked surface side. It does not need to extend radially outward beyond the rate portion.

[0041] In other words, since the folded portion of the bristle bundle is inscribed within the virtual bottom surface of the bristle planting hole, it does not protrude any further toward the back. Therefore, even if the bristle bundle is planted with the back side of the head portion in contact with a flat surface such as a workbench, the toothbrush of the present invention will not have any protruding portions interfering with the flat surface as described above. In this way, the toothbrush can be easily manufactured.

[0042] (10) The present invention provides a method for manufacturing a toothbrush, comprising a preparation step which is a step of preparing a toothbrush having a head portion having through-holes for implanting bristles, and an implantation step which is a step of folding a bundle of bristles, which is made up of a plurality of brushes, in half by applying a flat wire, and inserting the folded bundle of bristles and the flat wire together from one opening of the bristles implantation hole with the folded portion being the leading edge, and pushing until the folded portion is exposed at the other opening of the bristles implantation hole. Furthermore, the planting process is as follows: A bundle of bristles made up of multiple brushes is folded in half by applying a flat wire to it, and the fold The bundle of hair in this state and the flat wire together, with the folded portion which is the part that is folded in two at the front Insert from one opening of the hair follicle hole, and the folded portion into the other opening of the hair follicle hole The folded portion is exposed and protrudes from the head portion until part or all of the folded portion is exposed. Press so as not to spread the return portion radially outward beyond the straight portion that is continuous with the bristled surface side. It may also be a fitting process. Furthermore, a toothbrush having a head portion with through-holes for implanting bristles. The preparation process includes a toothbrush preparation process, which is the process of preparing the brush, and a bundle of bristles made by bundling multiple brushes together. By applying a flat wire, the bundle of hair in the folded state is folded in half and the flat wire is then used to connect the bundle of hair in half. In both cases, the folded portion, which is the part that folds in two, is inserted from one opening of the hair follicle hole. Furthermore, the folded portion is exposed at the other opening of the hair follicle, and the The folded portion is formed in a roughly columnar shape as a virtual back end surface in the inner space of the hair flocking hole. The straight section of the folded portion continues on the hair-planting surface side until it is inscribed within a virtual bottom surface of a hair-planting hole. The process may also include a planting step, which is a step of pushing the plant in so as not to spread it radially outward beyond the T-shaped portion. 。

[0043] In other words, the toothbrush manufacturing method of the present invention exposes the bristle bundles at the other opening, allowing the toothbrush to be used for cleaning the oral cavity. Furthermore, when washing, moisture such as saliva, medication, running water, or washing water can be wiped away by applying an absorbent material such as cloth, cotton, or paper to the exposed bristle bundles. By removing moisture in this way, the toothbrush can be kept clean.

[0044] (11) The planting process also includes an auxiliary tool preparation step, which is the step of preparing a flat wire pushing auxiliary tool having a concave recess on a flat surface, and the planting process is carried out such that the recess overlaps the other opening, the flat wire PushThe step may include attaching the auxiliary device to the other opening side of the head portion.

[0045] In other words, in the toothbrush manufacturing method of the present invention, the recessed portion of the flat wire pushing aid and the other opening of the bristle implantation hole overlap, allowing the folded portion protruding from the other opening to be inserted into the recessed portion. As a result, when the toothbrush is placed on a flat surface such as a workbench or apparatus via the flat wire pushing aid and the bristle bundle and the flat wire are pushed into the bristle implantation hole, such a workbench or apparatus does not obstruct the protrusion of the folded portion, allowing for efficient manufacturing.

[0046] (12) The planting step may also include the step of inserting the flat wire until the folded portion abuts the bottom of the recess.

[0047] In other words, since the folded portion of the bristle bundle abuts against the bottom of the recess of the flat wire pushing aid, the depth of the recess can regulate the length to which the folded portion protrudes from the other opening. This makes it possible to set the protruding length to be sufficient to wipe away moisture such as saliva, medicine, running water, and washing water with an absorbent material such as cloth, cotton, or paper, while also setting it to be not too long for ease of use, storage, and aesthetics. Moreover, because the friction between the flat wire and the groove is large, the straight portion is long, and the bristle bundle adheres more strongly to the inner wall, the bristle bundle can remain more securely in place and will not fall out, even when the plate thickness of the head portion is small. In this way, it is possible to manufacture a toothbrush that can be kept clean by removing moisture and can be used for a long time.

[0048] (13) In addition, in the toothbrush preparation step, a toothbrush may be prepared in which the bristle-planting holes have a reduced diameter portion in which the inner diameter is smaller than the opening diameter of one of the openings, and in the planting step, the folded portion may be pressed against the reduced diameter portion. Furthermore, the preparation step includes a toothbrush preparation step which is a step of preparing a toothbrush having a head portion having through bristle-planting holes, and a bundle of bristles made up of multiple brushes is folded in half by applying a flat wire, and the folded bundle of bristles and the flat wire together are inserted into one of the openings of the bristle-planting holes with the folded portion being the leading edge, and the folded portion is exposed at the other opening of the bristle-planting holes, and the folded portion is formed in a substantially columnar shape, which is the virtual back end face in the inner space of the bristle-planting holes. A method for manufacturing a toothbrush, comprising a toothbrush preparation step, in which the folded portion is pushed in so as not to expand radially outward more than the straight portion continuous with the bristle-planting surface side until it is inscribed with the virtual bottom surface of the pore or until part or all of the folded portion protrudes from the head portion, wherein in the toothbrush preparation step, a toothbrush is prepared in which the bristle-planting holes have a reduced diameter portion whose inner diameter is smaller than the opening diameter of one of the openings, and in the toothbrush preparation step, the folded portion is pushed in so as to come into contact with the reduced diameter portion. The method for manufacturing a toothbrush includes a preparation step, which is the step of preparing a toothbrush having a head portion having through-holes for implanting bristles, and an implantation step, which is the step of folding a bundle of bristles, in half by applying a flat wire, inserting the folded bundle of bristles and the flat wire together from one opening of the bristles implantation hole with the folded portion being the leading edge, exposing the folded portion at the other opening of the bristles implantation hole, and pushing the folded portion in such a way that it does not expand radially outward from the straight portion that is continuous with the bristles implantation surface side until part or all of the folded portion protrudes from the head portion, wherein in the toothbrush preparation step, a toothbrush is prepared in which the bristles implantation hole has a reduced diameter portion whose inner diameter is smaller than the opening diameter of the one opening, and in the implantation step, the folded portion is pushed in so as to come into contact with the reduced diameter portion.

[0049] In other words, when implanting the bristles, the folded portion is pressed against the narrowed diameter portion, so the bristle bundle is prevented from being pushed any further towards the other opening side by the narrowed diameter portion. Therefore, with the toothbrush manufacturing method of the present invention, the bristle bundle is implanted at a predetermined depth, and the toothbrush can be easily manufactured. Furthermore, the bristle bundle does not come out to the back side during use, and the brush does not fall out of the bristle implantation hole, so this toothbrush can be used for a long time. [Effects of the Invention]

[0050] In this way, it is possible to provide a toothbrush that can be kept clean by removing moisture that tends to accumulate on the bristles on the back of the head, and to provide a method for manufacturing such a toothbrush. Furthermore, by reducing the thickness of the head, it is possible to provide a toothbrush that is easier to clean the inside of the mouth, and to provide a method for manufacturing such a toothbrush. [Brief explanation of the drawing]

[0051] [Figure 1] (a) A diagram of a toothbrush 1 according to the first embodiment of the present invention. (b) A view of the toothbrush 1 of Figure 1(a) from the left side. [Figure 2] (a) A front cross-sectional view of the head portion 2 according to the first embodiment of the present invention. (b) A right side cross-sectional view of the head portion 2. [Figure 3] This shows a perspective view of a toothbrush 1 according to the first embodiment of the present invention. [Figure 4] This diagram illustrates the arrangement of the hair implantation holes 3 according to the first embodiment of the present invention. [Figure 5] This diagram shows a flow chart illustrating a method for manufacturing a toothbrush according to the first embodiment of the present invention, S1000. [Figure 6] This shows a front cross-sectional view of a flat wire pressing aid 8 according to the first embodiment of the present invention. [Figure 7] This diagram shows an explanatory view of the flat wire pressing aid 8 according to the first embodiment of the present invention, attached to the head portion 2. [Figure 8] (a) A front cross-sectional view of the head portion 102 according to a second embodiment of the present invention. (b) A right side cross-sectional view of the head portion 102. [Figure 9] (a) A schematic diagram of the cylindrical space C of the hair implantation hole 103 according to the second embodiment of the present invention. (b) A schematic diagram of the cylindrical space E of the reduced diameter portion. [Figure 10] This diagram shows a flow chart illustrating a method for manufacturing a toothbrush according to a second embodiment of the present invention, S1100. [Figure 11](a) A front cross-sectional view of the head portion 112 according to the third embodiment of the present invention. (b) A right side cross-sectional view of the head portion 112. [Figure 12] This diagram shows a flow chart illustrating a method for manufacturing a toothbrush according to a third embodiment of the present invention, S1200. [Figure 13] (a) A front cross-sectional view of the head portion 12 according to the fourth embodiment of the present invention. (b) A right side cross-sectional view of the head portion 12. [Figure 14] This diagram shows an explanatory view of the flat wire pressing aid 8 according to the fourth embodiment of the present invention, attached to the head portion 12. [Figure 15] This table shows the results of measuring the bristle-holding strength of a toothbrush 11 according to the fourth embodiment of the present invention. [Figure 16] This graph shows the results of measuring the bristle-holding strength of a toothbrush 11 according to the fourth embodiment of the present invention. [Figure 17] (a) A front cross-sectional view of the head portion 22 according to the fifth embodiment of the present invention. (b) A right side cross-sectional view of the head portion 22. [Figure 18] This diagram shows a flow chart illustrating a method for manufacturing a toothbrush according to a fifth embodiment of the present invention, S2000. [Figure 19] This diagram shows an explanatory view of the flat wire pressing aid 8 according to the fifth embodiment of the present invention, mounted on the head portion 22. [Modes for carrying out the invention]

[0052] [First Embodiment] Figures 1 to 7 illustrate a first embodiment of the present invention. In the figures, 1 is a toothbrush.

[0053] The head portion 2 of the toothbrush 1 has a bristle-planted surface 2a, and multiple round bristle-planted holes 3 are made in the bristle-planted surface 2a. Each bristle-planted hole 3 is arranged regularly, as shown in the example in Figure 1(a). The bristle-planted holes 3 penetrate from the bristle-planted surface 2a to the back surface 2b, which is the surface opposite the bristle-planted surface 2a relative to the head portion 2, as shown in Figures 2(a) and 2(b). Figure 3 shows the toothbrush 1 in the same state as in Figure 1(a) before the bristle bundles 4 are planted, and is a perspective view of the toothbrush 1 from an oblique angle. The toothbrush 1 is made of synthetic resin such as saturated polyester (PET), polypropylene (PP), or polyacetal resin (POM).

[0054] Multiple bristle bundles 4 for cleaning the inside of the oral cavity M, such as teeth and gums (not shown), are implanted in each bristle hole 3. Each bristle bundle 4 is formed by bundling together individual brush bristles 4a aligned in the longitudinal direction. In Figure 1(b), which is a view of the toothbrush 1 from the left side of Figure 1(a), only one bristle bundle 4 is shown with a solid line for clarity, while the remaining bristle bundles 4 are shown as a dotted line (imaginary line) in a bundled state. The user cleans the inside of the oral cavity M using the brush 4a on the bristle surface 2a side.

[0055] Figure 4 is an explanatory diagram showing the arrangement of the hair implantation holes 3. The state in which the hair bundles 4 are gathered together is shown by a dashed line, similar to Figure 1(b).

[0056] Each bristle bundle 4 is folded in half, and with the folded portion 5 at the beginning, it is pushed into each bristle implantation hole 3 and implanted. Figure 2(a) is a front partial cross-sectional view of the bristle bundle 4 folded in half by the flattened flat line 6 and pushed into the bristle implantation hole 3, viewed from the direction of the flattened surface of the flattened line 6. Figure 2(b) is a right side partial cross-sectional view of the head portion 2, viewed towards the flattened right side surface of the flattened line 6. The front partial cross-sectional view is a cross-sectional view including the cross-section of the flattened line 6, and the right side partial cross-sectional view is a cross-sectional view including the longitudinal section of the flattened line 6. Hatching is omitted to make symbols, leader lines, etc. easier to see. Note that Figure 1(a) shows the state before implantation of each bristle bundle 4 and insertion of the flattened line 6. Also, the description of the flattened line 6 is omitted in Figures 1(b) and 4.

[0057] The flat wire 6 is made of a material such as copper or brass and is hard enough to be driven into the synthetic resin head portion 2.

[0058] In Figure 2(a), arrows U, D, L, and R indicate the upper side (upward), lower side (downward), left side (leftward), and right side (rightward), respectively. In Figure 2(b), in addition to arrows U and D mentioned above, arrows F and B indicate the front side (forward) and rear side (backward), respectively.

[0059] Each bristle bundle 4 includes a straight section 7, which is a roughly columnar bundle that is continuous with the bristle-planted surface 2a side of the folded-over section 5. Here, the straight section 7 refers to the area from the upper end of the folded-over section 5 to the bristle-planted surface 2a in the vertical direction, as shown in Figure 2(a). Although not shown, the multiple brushes 4a constituting each bristle bundle 4 are arranged in a curved shape surrounding the lower end 6a of the horizontal line 6 in the folded-over section 5, and are arranged in a roughly straight line in the roughly vertical direction in the straight section 7.

[0060] At this time, the hair bundle 4 is pushed into the hair implantation hole 3, so the straight portion 7 comes into close contact with the hair implantation hole wall 3a, which is the inner wall of the hair implantation hole 3.

[0061] A portion of the folded portion 5 protrudes from the head portion 2 and is exposed at the opening on the back side 2b. The lower end of the folded portion 5 is located below the back side 2b, and the upper end of the folded portion 5 is located above the back side 2b.

[0062] The flat wire 6 is positioned such that its lower end 6a is located above the back surface 2b. That is, the inner space of the round flocking hole 3 is formed into a roughly cylindrical flocking hole cylindrical space C, and this flocking hole cylindrical space C has a virtual flocking hole virtual bottom surface Cb, which is a virtual end surface on the back surface 2b. The flat wire 6 is positioned such that its lower end 6a is located on the flocking surface 2a side of this virtual flocking hole virtual bottom surface Cb.

[0063] The flat wire 6 is driven in downwards and inserted from the entrance of the bristle-planting hole 3, and its two opposing edges 6b, 6b in the front-to-back direction advance partway through the bristle-planting hole 3, drawing two axial grooves 2c, 2c on the inner circumferential surface of the bristle-planting hole 3. However, because the two grooves 2c, 2c are shallow and narrow, even if the flat wire 6 tries to return upwards through the bristle-planting hole 3, a frictional force is generated in the axial direction of the bristle-planting hole 3 between the two edges 6b, 6b and the grooves 2c, 2c. As a result, each brush 4a remains planted without falling out of the bristle-planting hole 3.

[0064] As described above, the toothbrush 1 has its bristle bundle 4 exposed on the back side 2b, so when using the toothbrush 1 to clean the inside of the oral cavity M, and when washing, moisture such as saliva, medication, running water, and rinsing water can be wiped off by applying an absorbent material such as cloth, cotton, or paper to the exposed bristle bundle 4. By removing moisture in this way, the toothbrush 1 can be kept clean.

[0065] Furthermore, when the hair bundle 4 contacts the hair follicle wall 3a, the folded portion 5 does not contact the hair follicle wall 3a, whereas the hair bundle 4 contacts the hair follicle wall 3a at the straight portion 7. Even if an external force causes the hair bundle 4 to move upward out of the hair follicle 3, a frictional force is generated between the hair bundle 4 and the hair follicle wall 3a in the axial direction of the hair follicle 3 at the straight portion 7, causing the hair bundle 4 to remain in place.

[0066] Furthermore, in the toothbrush 1 of the present invention, the folded portion 5 is exposed from the head portion 2 on the back side 2b, and therefore the area in contact with the bristle hole wall 3a in the straight portion 7 is larger compared to toothbrushes where this exposure is not present. As a result, the frictional force is relatively large, and the bristle bundle 4 can be securely kept in the planted position.

[0067] Moreover, compared to a toothbrush where the wire is not exposed, the depth to which the flat wire 6 can be inserted is greater. As a result, the flat wire 6 can be pushed in more deeply, and the friction between the two edges 6b, 6b and their respective grooves 2c, 2c is greater.

[0068] Furthermore, by configuring the lower end 6a of the flat wire to be located on the bristle surface 2a side of the virtual base surface Cb of the bristle hole, the flat wire 6 does not protrude downwards from the virtual base surface Cb of the bristle hole. Therefore, accidents such as the flat wire 6 protruding from the head portion 2 and injuring the inside of the user's mouth M can be prevented.

[0069] [Manufacturing method] In Figure 5, S1000 illustrates a method for manufacturing a toothbrush according to the first embodiment of the present invention.

[0070] The manufacturing method S1000 of the present invention includes the preparation step S1010 and the implantation step S1020 in that order.

[0071] Preparation step S1010 includes toothbrush preparation step S1011 and auxiliary tool preparation step S1012. In toothbrush preparation step S1011, a toothbrush 1 is prepared, and bristle implantation holes 3 are provided in the head portion 2 of the toothbrush 1. The toothbrush 1 is formed by, for example, injection molding, with the head portion 2 and the handle portion continuous with the head portion 2 being molded.

[0072] On the other hand, in the auxiliary tool preparation step S1012, a flat wire pressing auxiliary tool 8 is prepared, which has a flat head receiving surface 8a with multiple concave recesses 9, as shown in the front section cross-sectional end view of Figure 6. In the flat wire pressing auxiliary tool 8, each recess 9 opens upward in the figure.

[0073] Each recessed portion 9 is approximately circular when viewed from the head portion receiving surface 8a, and the diameter of the recessed edge 9a, which is the boundary with the flat portion of the head portion receiving surface 8a, coincides with the diameter of each bristle-planting hole 3. The arrangement of each recessed portion 9 in the flat wire pressing aid 8 coincides with the arrangement of the bristle-planting holes 3 in the left-right and front-back directions in the head portion 2. The flat wire pressing aid 8 is made of a material harder than the flat wire 6; for example, if the flat wire 6 is made of brass, the flat wire pressing aid 8 is made of a metal harder than brass.

[0074] The planting process S1020 includes the steps of attaching the auxiliary device S1021, pushing it in S1022, and removing the auxiliary device S1023, in that order.

[0075] In the auxiliary tool attachment step S1021, the flat wire pressing aid 8 is attached to the head portion 2 such that the back surface 2b of the head portion 2 and the head portion receiving surface 8a of the flat wire pressing aid 8 come into contact. At this time, the back surface 2b and the head portion receiving surface 8a are arranged such that the back side opening edge 3b, which is the boundary between the flat surface of the back surface 2b and the back surface 2b side opening of each bristle hole 3, and the recessed edge 9a overlap. As a result, each bristle hole 3 and the corresponding recessed portion 9 are in communication.

[0076] In the pushing step S1022, the bundle of bristles 4, which consists of multiple brushes 4a, is folded in half by applying the flat wire 6. The folded bundle of bristles 4 and the flat wire 6 are then inserted together from the opening on the bristle surface 2a side of the bristle hole 3, with the folded portion 5 being the leading edge, and are pushed in until the folded portion 5 protrudes from the head portion 2 through the opening on the back surface 2b side of the bristle hole 3.

[0077] At this time, the flat wire 6 is driven in downwards, and its two edges 6b, 6b advance partway through the hair floss hole 3, drawing two grooves 2c, 2c. Figure 7 shows the flat wire pushing aid 8 attached to the head part 2, and the tip of the folded part 5 advances to the inside of the recessed part 9, as shown in Figure 7.

[0078] In the auxiliary tool removal step S1023, the flat wire pushing auxiliary tool 8 is removed from the head part 2 so that the head part receiving surface 8a is separated from the back surface 2b. After the auxiliary tool removal step S1023, the toothbrush 1 is completed with the brush 4a planted so that the bristle bundle 4 is exposed from the head part 2 on the back surface 2b side.

[0079] In this way, the toothbrush 1 cleans the inside of the oral cavity M using the brush 4a on the bristle surface 2a side, and since the bristle bundle 4 protrudes and is exposed from the head part 2 on the back side 2b, moisture such as saliva, medication, running water, and rinsing water can be wiped off by applying an absorbent material such as cloth, cotton, or paper to the protruding bristle bundle 4 during cleaning. By removing moisture in this way, the toothbrush 1 can be kept clean.

[0080] Furthermore, the recessed portion 9 of the flat wire pushing aid 8 and the opening on the back side 2b of the bristle implantation hole 3 overlap, and the bristle implantation hole 3 and the recessed portion 9 communicate with each other, allowing the folded portion 5 protruding from the opening on the back side 2b to be inserted into the recessed portion 9. As a result, when the toothbrush 1 is placed on a flat surface such as a workbench or device via the flat wire pushing aid 8 and the bristle bundle 4 and flat wire 6 are pushed into the bristle implantation hole 3, such a workbench or device does not obstruct the protrusion of the folded portion 5, and the toothbrush 1 can be manufactured efficiently.

[0081] [Second Embodiment] Figures 8 to 10 illustrate a second embodiment of the present invention. In the figures, 101 is a toothbrush.

[0082] The head portion 102 of the toothbrush 101 has a bristle surface 102a, and multiple round bristle holes 103 are made in the bristle surface 102a. As shown in Figures 8(a) and 8(b), the bristle holes 103 penetrate from the bristle surface 102a to the back surface 102b, which is the surface opposite the bristle surface 102a to the head portion 102.

[0083] Each bristled hole 103 has a reduced diameter portion 103c whose inner diameter is smaller than the opening diameter of the bristled surface 102a. The reduced diameter portion 103c forms an annular step at its upper end, forming a stepped edge 103d on the inside of this step. The stepped edge 103d forms a circle in plan view. The inner space occupied by the reduced diameter portion 103c forms a roughly cylindrical reduced diameter cylindrical space E between the stepped edge 103d and the back side opening edge 103b.

[0084] Figures 9(a) and 9(b) schematically represent the front cross-sectional views of the cylindrical space C of the hair flocking hole and the cylindrical space E of the reduced diameter portion, with the entire structure showing the hair flocking hole 103. Figure 9(a) shows the cylindrical space C of the hair flocking hole, and the shaded area in Figure 9(b) shows the cylindrical space E of the reduced diameter portion. Here, the cylindrical space C of the hair flocking hole has a virtual bottom surface Cb of the hair flocking hole, which is the virtual end surface on the back surface 102b side. The cylindrical space E of the reduced diameter portion has a virtual top surface Ea of the reduced diameter portion, which is the virtual end surface on the hair flocking surface 102a side, and a virtual bottom surface Eb of the reduced diameter portion, which is the virtual end surface on the back surface 102b side.

[0085] Since the reduced diameter portion 103c is located biased toward the back surface 102b side of the hair implantation hole 103, both of these virtual base surfaces Cb and Eb are located at the very bottom of the hair implantation hole 103. In other words, since the cylindrical space C of the hair implantation hole and the cylindrical space E of the reduced diameter portion coincide at the reduced diameter portion 103c located closer to the back surface 102b, the virtual base surface Cb of the hair implantation hole and the virtual base surface Eb of the reduced diameter portion coincide.

[0086] As shown in Figures 8(a) and 8(b), the flat wire 106 is positioned such that its lower end 106a is located on the side of the flocking surface 102a relative to the virtual bottom surface Cb of the flocking hole. Furthermore, the flat wire 106 is positioned so that its lower end 106a is externally tangent to the virtual top surface Ea of the reduced diameter portion and is in contact downward with the cylindrical space E of the reduced diameter portion. The pressed-in folded portion 105 then contacts the stepped edge 103d, completing the flocking of the bristle bundle 104.

[0087] The other components are the same as those of the first embodiment.

[0088] With this configuration, when implanting bristles in the toothbrush 101, the folded portion 105 of the bristle bundle 104 is prevented from being unnecessarily pushed towards the back side 102b by the stepped edge 103d of the diameter-reduced portion 103c. As a result, the bristle bundle 104 is implanted at a predetermined depth and can be easily manufactured. Furthermore, the bristle bundle 104 does not come out towards the back side 102b during use, and the brush 104a does not come out of the bristle implantation hole 103, allowing the toothbrush to be used for a long time.

[0089] Furthermore, since the diameter-reducing portion 103c is positioned biased toward the back surface 102b side of the bristle-planting hole 103, the depth to which the bristle bundle 104 is pushed in is restricted by this diameter-reducing portion 103c. As a result, the bristle bundle 104 is pushed in more deeply than when the diameter-reducing portion 103c is positioned closer to the bristle-planting surface 102a. Therefore, the area in contact with the bristle-planting hole wall 103a in the straight portion 107 is large, and the frictional force generated between the straight portion 107 and the bristle-planting hole wall 103a is large. Consequently, there is less risk of the bristle bundle 104 coming loose from the bristle-planting surface 102a side.

[0090] Furthermore, because the flat wire 106 can be inserted deeply, the frictional force generated between the flat wire 106 and the grooves 102c, 102c in the bristle implantation hole 103 is large, which prevents the flat wire 106 that holds the bristle bundle 104 from returning to the bristle implantation surface 102a side. This also reduces the risk of the bristle bundle 104 coming loose from the bristle implantation surface 102a side.

[0091] Furthermore, since the flat wire 106 is externally tangent to the virtual upper surface Ea of the reduced diameter portion, it does not penetrate any further into the reduced diameter portion 103c and become fitted. Therefore, there is no need to apply greater pressure to fit the flat wire 106 into the reduced diameter portion 103c, and the toothbrush 101 can be easily manufactured. On the other hand, compared to the case where the flat wire 106 does not externally tangent to the virtual upper surface Ea of the reduced diameter portion and remains above the virtual upper surface Ea of the reduced diameter portion, the flat wire 106 is pushed in more deeply. From this, the risk of the bristle bundle 104 coming loose from the bristle surface 102a side is small.

[0092] [Manufacturing method] In Figure 10, S1100 illustrates a method for manufacturing a toothbrush according to a second embodiment of the present invention.

[0093] The manufacturing method S1100 for the toothbrush 101 of the present invention includes the following steps in order: preparation step S1110 and implantation step S1120.

[0094] Preparation step S1110 includes toothbrush preparation step S1111 and auxiliary tool preparation step S1112. In toothbrush preparation step S1111, a toothbrush 101 is prepared, and bristle implantation holes 103 are provided in the head portion 102 of the toothbrush 101. The toothbrush 101 is formed by, for example, injection molding, with the head portion 102 and the handle portion continuous with the head portion 102 being molded.

[0095] In this case, the bristles-planted hole 103 has a reduced diameter portion 103c whose inner diameter is smaller than the opening diameter of the bristles-planted surface 102a. The reduced diameter portion 103c forms an annular step at its upper end, forming a stepped edge 103d which is the edge inside this step. The stepped edge 103d forms a circle in plan view.

[0096] Next, the planting process S1120 includes the steps of attaching the auxiliary tool S1121, pushing in S1122, and removing the auxiliary tool S1123 in that order.

[0097] In the pushing step S1122, the bundle of bristles 104, which consists of multiple brushes 104a, is folded in half by applying the flat wire 106. The folded bundle of bristles 104 and the flat wire 106 are then inserted together from the opening on the bristle surface 102a side of the bristle hole 103, with the folded portion 105 being the leading edge, and are pushed in until the folded portion 105 protrudes from the head portion 102 through the opening on the back surface 102b side of the bristle hole 103.

[0098] The pushing step S1122 includes the folding portion contact step S1122a. Due to the pushing portion contact step S1122a, the bristle bundle 104 advances through the bristle implantation hole 103, and as a result, the folding portion 105 comes into contact with the stepped edge 103d. This step edge 103d prevents it from advancing any further, and the implantation is completed.

[0099] Other processes and steps are the same as those for the toothbrush manufacturing method in the first embodiment.

[0100] This manufacturing method ensures that during bristle implantation, the folded portion 105 is pressed against the diameter-reducing portion 103c. As a result, the bristle bundle 104 is prevented from being pushed further towards the back side 102b by the diameter-reducing portion 103c. Therefore, the bristle bundle 104 is implanted at a predetermined depth, and the toothbrush 101 can be easily manufactured. Furthermore, the bristle bundle 104 does not come loose towards the back side 102b during use, and the brush 104a does not fall out of the bristle implantation hole 103, allowing the toothbrush 101 to be used for a long time.

[0101] [Third Embodiment] Figures 11 and 12 illustrate a third embodiment of the present invention. In the figures, 111 is a toothbrush.

[0102] The head portion 112 of the toothbrush 111 has a bristle surface 112a, and multiple round bristle holes 113 are made in the bristle surface 112a. As shown in Figures 11(a) and (b), the bristle holes 113 penetrate from the bristle surface 112a to the back surface 112b, which is the surface opposite the bristle surface 112a to the head portion 112.

[0103] Each hair flocking hole 113 has a reduced diameter portion 113c whose inner diameter is smaller than the opening diameter at the hair flocking surface 112a. The upper end of the reduced diameter portion 113c forms an annular step, which forms a stepped edge 113d on the inside of this step. The stepped edge 113d forms a circle in plan view. The inner space occupied by the reduced diameter portion 113c forms a roughly cylindrical reduced diameter cylindrical space E between the stepped edge 113d and the back side opening edge 113b. The virtual bottom surface Eb of the reduced diameter cylindrical space E, which is the virtual back side 112b end surface, coincides with the virtual bottom surface Cb of the hair flocking hole, which is the virtual back side 112b end surface of the reduced hair flock cylindrical space C.

[0104] The bristle bundle 114 has a folded portion 115 that is pressed into the cylindrical space C of the bristle hole, and this folded portion is inscribed with the virtual bottom surface Cb of the bristle hole. In this way, the toothbrush 111 exposes the bristle bundle 114 on the back side 112b, so when the toothbrush 111 is used for cleaning the inside of the oral cavity M, and when washing, moisture such as saliva, medication, running water, and washing water can be wiped off by applying an absorbent material such as cloth, cotton, or paper to the exposed bristle bundle 114. By removing moisture in this way, the toothbrush 111 can be kept clean.

[0105] The other components are the same as those of the second embodiment.

[0106] With this configuration, the folded portion 115 of the toothbrush 111 is inscribed within the virtual bottom surface Cb of the bristle hole, and the bristle bundle 114 does not protrude any further toward the back surface 112b. Therefore, even if the bristle bundle 114 is planted with the back surface 112b of the head portion 112 in contact with a flat surface such as a workbench, the protruding portion of the toothbrush 111 does not interfere with the aforementioned surface. In this way, the toothbrush 111 can be easily manufactured.

[0107] [Manufacturing method] In Figure 12, S1200 illustrates a method for manufacturing a toothbrush according to a third embodiment of the present invention.

[0108] The manufacturing method S1200 for the toothbrush 111 of the present invention includes the preparation step S1210 and the implantation step S1220 in that order. The preparation step S1210 includes the toothbrush preparation step S1211. The implantation step S1220 also includes the pressing step S1222. The pressing step 1222 includes the folded portion contact step S1222a. In the folded portion contact step S1222a, the folded portion 115 contacts the stepped edge 113d and is inscribed within the virtual bottom surface Cb of the bristle hole.

[0109] These processes and steps are the same as those for the toothbrush manufacturing method in the second embodiment. In this embodiment, the folded portion 115 of the toothbrush 111 does not protrude from the back surface 112b, so the flat wire pushing aid 8 used in the second embodiment is not necessarily required. Therefore, in the manufacturing method of this embodiment, the aid preparation step S1112, the aid attachment step S1121, and the aid removal step S1123 included in the manufacturing method of the second embodiment are not necessarily required.

[0110] [Fourth Embodiment] Figures 13 to 16 illustrate a fourth embodiment of the present invention. In the figures, 11 is a toothbrush.

[0111] The head portion 12 of the toothbrush 11 has a bristle-planted surface 12a, and multiple round bristle-planted holes 13 are made in the bristle-planted surface 12a. The bristle-planted holes 13 penetrate from the bristle-planted surface 12a to the back surface 12b, as shown in Figures 13(a) and (b). Multiple bristle bundles 14 are planted in each bristle-planted hole 13, and each bristle bundle 14 is formed by bundling individual bristles 14a together. Each bristle bundle 14 is folded in half, and with the folded portion, the folded-over part 15, at the front, it is pushed into each bristle-planted hole 13 and planted. Figures 13(a) and (b) are front and right side cross-sectional views, respectively, showing the state in which the bristle bundles 14 are folded in half by a flat line 16 and pushed into the bristle-planted holes 13.

[0112] Each hair bundle 14 includes a straight section 17, which is a roughly columnar bundle that is continuous with the hair implantation surface 12a side of the folded-over section 15. As the hair bundle 14 is pushed into the hair implantation hole 13, the straight section 17 comes into close contact with the hair implantation hole wall 13a, which is the inner wall of the hair implantation hole 13.

[0113] The folded portion 15 protrudes from the head portion 12 and is exposed at the opening on the back surface 12b. The lower end of the folded portion 15 is located below the back surface 12b, and the upper end of the folded portion 15 coincides with the vertical position of the back surface 12b.

[0114] The flat wire 16 is driven in downwards, and its two edges 16b, 16b advance so as to trace two grooves 12c, 12c until it approaches the lower end of the hair flocking hole 13. The flat wire 16 is positioned such that its lower end 16a is above the back surface 12b. In other words, the flat wire 16 is positioned such that its lower end 16a is on the hair flocking surface 12a side of the virtual bottom surface Cb of the hair flocking hole that has the cylindrical space C of the hair flocking hole 13.

[0115] The lower end of the straight section 17 coincides with the vertical position of the back surface 12b. That is, the thickness of the head section 12 and the height of the straight section 17 are the same, and the entire bristle flocking hole wall 13a is in close contact with the straight section 17.

[0116] Figure 14 shows the flat wire pushing aid 8 attached to the head portion 12, and the folded portion 15 advances to the inside of the recessed portion 9 as shown in Figure 14.

[0117] The other components are the same as those of the first embodiment.

[0118] In the toothbrush 11 of the present invention, the entire folded portion 15 protrudes from the head portion 12 on the back side 12b, so that the straight portion 17 is in close contact with the entire bristle hole wall 13a. As a result, the area in contact between the bristle bundle 14 and the bristle hole wall 13a is larger, the frictional force is greater, and the bristle bundle 14 can be securely fixed in place.

[0119] [Examples] Figure 15 shows the results of measuring the bristle retention strength when the bristle bundle 14 is pulled out of the bristle hole 13 after the brush 14a is implanted in the bristle hole 13 using a flat wire 16 as shown in Figure 13, in the toothbrush 11. The brush 14a used was made of nylon, with a thickness of 6 mil and a length of 33 mm. The toothbrushes 11 were prepared with bristle hole 13 diameters of 1.0 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, and 2.0 mm, and head portion 12 plate thicknesses represented by the symbol t in Figure 4 were 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, and 5.0 mm, respectively. For each diameter of bristle implantation hole 13, the number of brushes 14a constituting each bristle bundle 14 was set as follows: 22 brushes for 1.0 mm (by folding back 11 brushes 14a), 40 brushes for 1.2 mm, 52 brushes for 1.4 mm, 72 brushes for 1.6 mm, 90 brushes for 1.8 mm, and 114 brushes for 2.0 mm.

[0120] When implanting the bristle bundles 14, a flat wire pushing aid 8 was used in accordance with the toothbrush manufacturing method S1000.

[0121] The bristle retention strength test was performed using a tensile testing machine in accordance with the explanation in the aforementioned "Toothbrush JIS S 3016-1995" standard. The pull-out speed in the strength test using the tensile testing machine was set to 20 mm / min.

[0122] The table in Figure 15 shows the average value of the bristle-holding strength (N) when the above-mentioned number of brushes 14a are implanted, and a strength test is performed three times for each, with each row representing the plate thickness (mm) of the respective head portion 12 and each column representing the diameter of the bristle-planting hole (mm).

[0123] Figure 16 shows graphs for each diameter of the bristle holes 13, with the vertical axis showing the bristle-holding strength (N) and the horizontal axis showing the plate thickness (mm) of the head portion 12. As shown in the values ​​in Figure 15 and the graphs in Figure 16, the bristle-holding strength is 15.0N or greater for all cases where the plate thickness of the head portion 12 is 1.5 mm or more and 5.0 mm or less, which is greater than the stipulated value of 8N based on the resolution of the Japanese Industrial Standards Committee dated June 1, 1990. Therefore, the toothbrush 11 of the present invention can have the plate thickness of the head portion 12 set to 1.5 mm or more and 5.0 mm or less.

[0124] On the other hand, in the graphs mentioned above, it was found that when the diameter of the flocking hole 13 is 1.0 mm, the flocking strength peaks when the head portion 12 has a plate thickness of 4.0 mm, and when the plate thickness is 4.0 mm or more, the flocking strength decreases with increasing plate thickness. Furthermore, it was found that 1.5 mm is the minimum limit size for the plate thickness of the head portion 12 in terms of the processing of forming the flocking hole 13 of the above dimensions and driving in the flat wire 16. Thus, when flocking bundles 14 into the straight flocking hole 13 of the above dimensions, it is more preferable that the plate thickness of the head portion 12 be formed in the range of 1.5 mm or more and less than 4.0 mm.

[0125] Therefore, the toothbrush 11 of the present invention can have a more desirable bristle-holding strength as a toothbrush by forming the plate thickness of the head portion 12 to be in the range of 1.5 mm or more and less than 4.0 mm.

[0126] Furthermore, even with extremely thin head sections 12, such as those with a thickness of 1.5 mm or more but less than 2.0 mm, the hair-stopping strength reaches 15.0 N or more. Moreover, even with thin head sections, such as those with a thickness of 2.0 mm or more but less than 2.5 mm, the hair-stopping strength reaches 25.0 N or more.

[0127] As described above, by reducing the thickness of the head portion 12, the toothbrush 11 can reach the back teeth more easily and clean the inside of the mouth more effectively. Therefore, the toothbrush 11 of the present invention makes it easier to clean the inside of the mouth, and the bristles 14a are less likely to fall out, allowing for longer use.

[0128] [Fifth Embodiment] Figures 17 to 19 illustrate a fifth embodiment of the present invention. In the figures, 21 is a toothbrush.

[0129] The head portion 22 of the toothbrush 21 has a bristle-planted surface 22a, and multiple round bristle-planted holes 23 are made in the bristle-planted surface 22a. The bristle-planted holes 23 penetrate from the bristle-planted surface 22a to the back surface 22b, as shown in Figures 17(a) and (b). Multiple bristle bundles 24 are planted in each bristle-planted hole 23, and each bristle bundle 24 is formed by bundling individual bristles 24a together. Each bristle bundle 24 is folded in half, and with the folded portion, the folded-over part 25, at the front, it is pushed into each bristle-planted hole 23 and planted. Figures 17(a) and (b) are front and right side cross-sectional views, respectively, showing the state in which the bristle bundles 24 are folded in half by a flat line 26 and pushed into the bristle-planted holes 23.

[0130] Each hair bundle 24 includes a straight section 27, which is a roughly columnar bundle that is continuous with the hair implantation surface 22a side of the folded-over section 25. As the hair bundle 24 is pushed into the hair implantation hole 23, the straight section 27 comes into close contact with the hair implantation hole wall 23a, which is the inner wall of the hair implantation hole 23.

[0131] The folded portion 25 protrudes from the head portion 22 and is exposed at the opening on the back surface 22b. The lower end of the folded portion 25 is located below the back surface 22b, and the upper end of the folded portion 25 coincides with the vertical position of the back surface 22b.

[0132] The flat wire 26 is driven in facing downwards, and its two edges 26b, 26b trace two grooves 22c, 22c, advancing until the lower end 26a of the flat wire reaches the back surface 22b of the head portion 22. That is, the lower end 26a of the flat wire 26 is inscribed within the virtual bottom surface Cb of the hair flock hole 23, and is positioned to be in contact with the virtual bottom surface Cb of the hair flock hole facing downwards. The lengths of the two grooves 22c, 22c are equal to the thickness of the head portion 22.

[0133] The lower end of the straight section 27 coincides with the vertical position of the back surface 22b. That is, the thickness of the head section 22 and the height of the straight section 27 are the same, and the entire bristle flocking hole wall 23a is in close contact with the straight section 27.

[0134] The other components are the same as those of the fourth embodiment.

[0135] In the toothbrush 11 of the present invention, the flat wire 26 is positioned at the lowest part of the bristle hole 23, so that the bristle bundle 24 is pressed radially outward at the deepest part of the bristle hole 23. As a result, the bristle bundle 24 adheres more strongly to the wall 23a of the bristle hole. This allows the bristle bundle 24 to remain more securely in its planted position. In addition, the two grooves 22c, 22c are the longest, and the friction between the two edges 26b, 26b and their respective grooves 22c, 22c is also greater.

[0136] Furthermore, since the lower end 26a of the flat wire is configured to be inscribed within the virtual base surface Cb of the bristle implantation hole, the flat wire 26 does not protrude downwards from the virtual base surface Cb of the bristle implantation hole. Therefore, accidents such as the flat wire 26 protruding from the head portion 22 and injuring the inside of the user's mouth M can be prevented.

[0137] [Manufacturing method] In Figure 18, S2000 illustrates a method for manufacturing a toothbrush 21 according to a fifth embodiment of the present invention.

[0138] The pushing step S2022 of the toothbrush manufacturing method S2000 includes a flat wire setting step S2022a, which is the step of inserting the flat wire 26 until each folded portion 25 contacts the bottom of the recess 9b, which is the bottom of each recess 9 into which it is inserted. At this time, the flat wire pushing aid 8 shown in Figure 6 is configured such that the depth of the recess 9 matches the vertical height of each folded portion 25. As a result, the flat wire 26 is prevented from entering the downward-facing bristle holes 23 by the lower end of each folded portion 25 contacting the bottom of the recess 9b.

[0139] Furthermore, since the flat wire pushing aid 8 is made of a harder material than the flat wire 26, even if you try to push the flat wire 26 further in, the lower end 26a of the flat wire will not be embedded in the head receiving surface 8a.

[0140] Figure 19 shows the flat wire pressing aid 8 attached to the head portion 22, with the folded portion 25 fitted inside the recessed portion 9, and the lower end of the folded portion 25 in contact with the bottom of the recess 9b.

[0141] Other processes and steps are the same as those for the toothbrush manufacturing method in the fourth embodiment.

[0142] In this way, the depth of the recess 9 can regulate the length to which the folded portion 25 protrudes from the opening on the back side 22b. This makes it possible to set the protruding length to be sufficient to wipe away moisture such as saliva, medicine, running water, and washing water with an absorbent material such as cloth, cotton, or paper, while also setting it to be not too long for ease of use, storage, and aesthetics. In this way, a toothbrush 21 that can be kept clean by removing moisture can be manufactured.

[0143] Although embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications are possible without departing from the spirit of the invention.

[0144] For example, the bristle implantation holes do not have to be round; they can be formed into oval or square holes as long as the brush bristles can be bundled together and implanted.

[0145] Furthermore, the number of bristle implantation holes provided in the head does not have to be multiple; a single bristle implantation hole is also acceptable. Accordingly, the bristle bundle implanted may also be a single unit. Moreover, the recess provided in the flat wire pushing aid may also be a single unit.

[0146] When the folded portion protrudes from the head portion and is exposed, the rear opening edge of the flat wire pushing aid does not have to be the same diameter as the recessed edge, and may be smaller or larger in diameter than the recessed edge, as long as it does not interfere with the protrusion of the folded portion from the head portion.

[0147] The flat wire does not need to be made of metal; it can be made of plastic, for example, as long as it is hard enough to be driven into the head.

[0148] If the folded portion protrudes from the head portion and is exposed, when driving in the flat wire, if the protrusion of the folded portion from the head portion does not interfere, the flat wire may be driven in without using a flat wire pushing aid. For example, the head portion may be supported in the air with one hand and the bundle of hair with the other hand.

[0149] When attaching the bristles to the head, instead of using flat wire, the bristles may be fixed to the head by welding, for example.

[0150] The upper end of the flat wire does not necessarily have to be tangent to the virtual upper surface of the reduced diameter section. It may be located above the virtual upper surface of the reduced diameter section as long as the flat wire can be pushed in deeply enough so that the bristle bundle does not slip out from the bristle implantation surface.

[0151] Even if the diameter-reducing portion is not biased towards the back side, it may be provided such that the virtual bottom surface of the diameter-reducing portion is located above the virtual bottom surface of the bristle-planting hole, as long as the flat wire can be pushed in deeply enough so that the bristle bundle does not slip out from the bristle-planting surface. [Industrial applicability]

[0152] The present invention can be used in a toothbrush manufacturing method that includes a toothbrush preparation step of preparing a toothbrush in which the bristle holes penetrate the head portion and a toothbrush having a head portion provided with the penetrating bristle holes. [Explanation of Symbols]

[0153] 1,11,21,101,111 toothbrush 2,12,22,102,112 Head section 3,13,23,103,113 Hair transplant pores 103c,113c Reduced diameter part 4, 14, 24, 104, 114 hair bundles 4a,14a,24a,104a,114a brush 5,15,25,105,115 Folded section 6,16,26,106,116 Flat line 7,17,27,107,117 Straight section 8. Flat wire pushing aid 9. Recessed area C. Columnar space of hair follicle (approximately columnar) Cb virtual base of hair transplant hole E Cylindrical space in the reduced diameter region Ea Virtual upper surface of reduced diameter section Eb Virtual bottom surface of reduced diameter section S1000, S1100, S1200, S2000 Toothbrush Manufacturing Method S1010,S1110,S1210,S2010 Preparation process S1011, S1111, S1211, S2011 Toothbrush preparation process S1012,S1112,S2012 Auxiliary tool preparation process S1020,S1120,S1220,S2020 Planting process S1021, S1121, S2021 Assistive device attachment step S1022, S1122, S1222, S2022 Push-in step S1023, S1123, S2023 Auxiliary device removal step

Claims

1. A toothbrush comprising a brush and a head portion into which a bundle of bristles formed by bundling multiple brushes is implanted, wherein the head portion has a bristle-implanting surface and bristle-implanting holes are made on the bristle-implanting surface, the bristle bundle is folded in half, and in this folded state, the folded portion is implanted in the bristle-implanting holes with the folded part being the leading edge, The aforementioned bristle implantation holes penetrate the back surface of the head portion opposite to the bristle implantation surface, The bundle of hair has the folded portion exposed at the opening on the back side, and part or all of the folded portion protrudes from the head portion. The folded portion shall not extend radially outward more than the straight portion that is continuous with the flocked surface. A toothbrush characterized by the following features.

2. Having a flat wire that is driven into the aforementioned hair implantation hole, The bundle of hair is folded in half by the flat wire and pushed into the hair implantation hole. The toothbrush according to feature 1.

3. The hair implantation hole has an internal space formed in a roughly columnar shape, The flat wire is arranged such that the lower end of the flat wire, which is one side on the back side, is located on the flocking surface side of the substantially columnar shape, which is a virtual end face located on the back side, or the virtual bottom surface of the flocking hole. The toothbrush according to feature 2.

4. The hair implantation hole has an internal space formed in a roughly columnar shape, The flat wire is positioned such that its lower end, which is one side on the back side, is inscribed within the virtual bottom surface of the hair follicle, which is a virtual end face of the substantially columnar body located on the back side. The toothbrush according to feature 2.

5. The thickness of the head portion is formed to be in the range of 1.5 mm or more and less than 4.0 mm. The toothbrush according to feature 3 or 4.

6. The aforementioned hair follicle hole has a reduced diameter portion whose inner diameter is smaller than the opening diameter of the hair follicle surface. The toothbrush according to feature 1.

7. The reduced diameter portion is formed such that the virtual bottom surface of the reduced diameter portion, which is the virtual rear end face of its inner space, coincides with the virtual bottom surface of the hair implantation hole, which is the virtual end face located on the rear side of the inner space of the hair implantation hole, which is formed in a substantially columnar shape. The toothbrush according to feature 6.

8. The flat wires driven into the aforementioned flocking holes are positioned such that the lower end of the flat wire, which is one side on the back side, is tangent to the virtual upper surface of the reduced diameter portion, which is the virtual end surface on the flocking surface side of the inner space of the reduced diameter portion. The toothbrush according to feature 7.

9. A preparation process including a toothbrush preparation step, which is the step of preparing a toothbrush having a head portion with through-holes for implanting bristles, The process includes a bristle-planting step in which a bundle of multiple brushes is folded in half by applying a flat wire, and both the folded bristle bundle and the flat wire are inserted into one opening of the bristle-planting hole with the folded portion (the folded part) at the front, and the folded portion is exposed at the other opening of the bristle-planting hole and pushed in so as not to spread radially outward from the straight portion that is continuous with the bristle-planting surface of the folded portion until part or all of the folded portion protrudes from the head portion. A method for manufacturing a toothbrush, characterized by the following features.

10. A preparation process including a toothbrush preparation step, which is the step of preparing a toothbrush having a head portion with through-holes for implanting bristles, A method for manufacturing a toothbrush, comprising: a bristle bundle formed by bundling multiple bristles together, which is folded in half by applying a flat wire; inserting the folded bristle bundle and the flat wire together into one opening of the bristle planting hole, with the folded portion being the leading edge; exposing the folded portion at the other opening of the bristle planting hole; and pushing the folded portion in so as not to spread radially outward from the straight portion continuous with the bristle planting surface side of the bristle planting hole until part or all of the folded portion protrudes from the head portion, the method comprising: a planting step, In the toothbrush preparation step, a toothbrush is prepared in which the bristle-planting holes have a reduced diameter portion in which the inner diameter is smaller than the opening diameter of one of the openings. In the planting process, the folded portion is pressed against the reduced diameter portion. A method for manufacturing a toothbrush, characterized by the following features.

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