Toothbrush and production method of the same

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 in which implant holes penetrate 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 implant holes that penetrate therethrough.

Background Art

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

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

[0004] The flat wire is a thin plate such as a square metal plate, is inserted from the entrance of the implant hole, and the edges of its opposite two sides proceed to the middle of the implant hole so as to draw two axial grooves on the inner peripheral surface in the implant hole. However, since the two grooves are narrow, even when the flat wire tries to return in the reverse direction through the implant hole, a frictional force in the axial direction of the implant hole 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 implant holes.

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

[0006] Thus, the conventional toothbrush can securely fix the bristles to the head portion while adopting a simple assembly method of driving the flat wire and the tuft into the implant holes.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

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

[0009] On the other hand, when the toothbrush is used for cleaning in the oral cavity such as teeth and gums, moisture such as the user's saliva and chemical liquid during cleaning may accumulate at the bottom of the implanting hole along the bristles. Also, moisture such as running water and washing water for cleaning the toothbrush may accumulate. Since the tufts of bristles are fitted in the implanting holes, it is difficult for these moisture to flow back and be discharged from the implanting holes. Further, since the bristles on the bottom side are accommodated inside the closed implanting holes, it is not easy to dry them with gases such as air and gas, and it is impossible to wipe them with water - absorbing materials such as cloth, cotton, and paper.

[0010] As a result, it is easy for various bacteria to multiply due to the accumulation of the above - mentioned moisture, and the toothbrush cannot be kept clean.

[0011] In view of such problems, an object of the present invention is to provide a toothbrush that can keep clean by removing moisture that tends to accumulate on the bristles on the back side of the head portion, and to provide a method for manufacturing such a toothbrush.

Means for Solving the Problems

[0012] (1) The present invention provides a toothbrush comprising bristles and a head portion for implanting tufts of a plurality of said bristles, said head portion having a planting surface with planting holes formed therein, said tufts being folded in two and implanted in said planting holes with the folded-back portion, which is the portion where the two-fold occurs, at the front. The planting holes penetrate through the back surface of the head portion opposite to the planting surface, and the tufts are characterized in that the folded-back portion is exposed at the opening on the back surface side.

[0013] That is, in the toothbrush of the present invention, since the tufts expose the folded-back portion at the opening on the back surface side, when the toothbrush is used for cleaning in the oral cavity and when it is washed, moisture such as saliva, chemical solution, running water, and washing water can be wiped off by applying a water-absorbing material such as cloth, cotton, or paper to the exposed tufts. By removing the moisture in this way, the toothbrush can be kept clean.

[0014] Also, when the tuft contacts the inner wall of the planting hole, the folded-back portion where the tuft makes a U-turn does not contact the inner wall, whereas the tuft contacts the inner wall at the straight portion, which is a substantially columnar bundle continuous with the planting surface side of the folded-back portion. Even when an external force attempts to cause the tuft to withdraw in the opposite direction from the planting hole, a frictional force is generated between the tuft and the inner wall in the axial direction of the planting hole at this straight portion, causing the tuft to stay.

[0015] Therefore, since the toothbrush of the present invention is configured such that the folded-back portion is exposed on the back surface side, the area of contact between the straight portion and the inner wall is larger compared to a toothbrush where such exposure does not occur. Also, even if the plate thickness of the head portion is configured to be smaller, the frictional force is large, and the tuft can surely stay in the implanted position. And by staying in the implanted position, a water-absorbing material can always be applied to the exposed tuft, keeping the toothbrush clean. Moreover, it reduces the detachment of the bristles from the planting holes, enabling this toothbrush to be used for a long time.

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

[0017] (2) Further, it may have a flat wire driven into the implanting hole, and the tuft may be folded in two by the flat wire and pushed into the implanting hole.

[0018] That is, the flat wire is inserted from the entrance of the implanting hole, and the edges of the two opposite sides thereof advance into the implanting hole so as to draw two axial grooves on the inner peripheral surface in the implanting hole. However, since the two grooves are shallow and the width of the grooves is narrow, even when the flat wire tries to return in the reverse direction of the implanting hole, a frictional force in the axial direction of the implanting hole is generated between the edges of the two sides and the grooves. As a result, the brush maintains the implanted state without being removed from the implanting hole.

[0019] At this time, for example, when there are two types of head portions having the same plate thickness, and the folded-back portion is not exposed in one head portion and the folded-back portion is exposed in the other head portion, the other head portion can fold the tuft at a deeper position, and the depth of the other head portion at the same depth is larger than the depth at which the flat wire can be inserted into the one head portion. Thus, since the toothbrush of the present invention is configured such that the folded-back portion is exposed in the head portion, the flat wire can be pushed deeper, and the friction between the edges of the two sides and the grooves is large.

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

[0021] By reducing the thickness of the head portion, 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) Further, the inner space of the implanting hole is formed in a substantially cylindrical shape, and the horizontal line may be arranged such that the lower end of the horizontal line on the back side, which is one side of the back side, is located closer to the implanting surface side than the virtual bottom surface of the implanting hole, which is the virtual end surface on the back side of the substantially cylindrical shape.

[0023] That is, by configuring one side of the horizontal line to be located closer to the implanting surface side than the virtual bottom surface of the implanting hole, the horizontal line does not protrude from the back side of the head portion more than the virtual bottom surface of the implanting hole. Therefore, it is possible to prevent an accident in which the horizontal line protrudes from the head portion 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 horizontal line.

[0025] (4) Further, the inner space of the implanting hole is formed in a substantially cylindrical shape, and the horizontal line may be arranged such that the lower end of the horizontal line on the back side, which is one side of the back side, is inscribed in the virtual bottom surface of the implanting hole, which is the virtual end surface on the back side of the substantially cylindrical shape.

[0026] That is, by configuring the horizontal line to be inscribed in the virtual bottom surface of the implanting hole, the horizontal line does not protrude from the back side of the head portion more than the virtual bottom surface of the implanting hole. Therefore, it is possible to prevent an accident in which the horizontal line protrudes from the head portion and damages the user's oral cavity.

[0027] At the same time, since it is inscribed in the virtual bottom surface of the implanting hole, the horizontal line can be arranged at the deepest position of the implanting hole. Therefore, the friction between the horizontal line and the groove is large, the straight portion is long, and the hair bundle adheres strongly to the inner wall. Even when the plate thickness of the head portion is small, the hair bundle can stay in the more securely implanted position and cannot be pulled out.

[0028] In this way, the toothbrush of the present invention can be used for a long time and cleanly while preventing injuries in the oral cavity by the horizontal line.

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

[0030] Even when the toothbrush of the present invention is configured with a small plate thickness of the head portion, the hair bundle stays in the securely implanted position.

[0031] Conventionally, the plate thickness of the head portion in a thin toothbrush is said to be about 2.5 mm. By the way, regarding toothbrushes, according to the explanation of "Toothbrush JIS S 3016-1995" revised by the Japanese Industrial Standards Committee (now the Japanese Standards Association) on March 1, 1995, based on the resolution of the Japanese Industrial Standards Committee on June 1, 1990, the hair retention strength is defined as "the maximum tensile force is 8 N or more". Therefore, the inventor has found that in the case of the toothbrush of the present invention, even when the plate thickness of the head portion is as thin as about 1.5 mm by experiment, the hair retention strength shows a value of 15 N or more, which is larger than the above-mentioned specified value of 8 N. Further, it has been found that even when the plate thickness of the head portion is 1.5 mm or more and less than 4.0 mm, the above-mentioned value of 15 N or more is shown. Furthermore, also by experiment, even when the plate thickness of the head portion is 4.0 mm or more and 5.0 mm or less, although the hair retention strength decreases when the implanting hole has a partial small diameter, it has still been found that the above-mentioned value of 15 N or more is shown.

[0032] Thus, the toothbrush of the present invention can have the plate thickness of the head portion set in the range of 1.5 mm or more and 5.0 mm or less, and can also be formed in the range of 1.5 mm or more and less than 4.0 mm, so that it can sufficiently have a more desirable hair retaining strength as a toothbrush.

[0033] (6) Further, the hair implanting hole may have a reduced diameter portion whose inner diameter is smaller than the opening diameter on the hair implanting surface.

[0034] That is, during hair implantation, the hair bundle is blocked by the reduced diameter portion of the hair implanting hole and is not pushed into the back side unnecessarily. Therefore, in the toothbrush of the present invention, the hair bundle is implanted at a predetermined depth and can be easily manufactured. Also, during use, the hair bundle does not come out to the back side, and the bristles do not fall out from the hair implanting hole, so this toothbrush can be used for a long time.

[0035] (7) Further, the reduced diameter portion may have the virtual bottom surface of the reduced diameter portion, which is the virtual back side end surface of the inner space thereof, coincide with the virtual bottom surface of the hair implanting hole.

[0036] That is, since the virtual bottom surface of the reduced diameter portion coincides with the virtual bottom surface of the hair implanting hole, the reduced diameter portion is provided offset to the back side of the hair implanting hole. And since the pushing depth of the hair bundle is regulated by the reduced diameter portion, compared with the case where the reduced diameter portion is provided closer to the hair implanting surface, the hair bundle is pushed in deeper, and the area of contact between the straight portion and the inner wall of the hair implanting hole is large. Therefore, the frictional force generated between the straight portion and the inner wall is large, and the risk of the hair bundle coming out from the hair implanting surface side is small.

[0037] Also, since the flat wire can be inserted deeper, the frictional force generated between the flat wire and the groove in the hair implanting hole is large, and the flat wire for suppressing the hair bundle is suppressed from returning to the hair implanting surface side. Also by this, the risk of the hair bundle coming out from the hair implanting surface side is small.

[0038] (8) Further, the horizontal line may be arranged such that the lower end of the horizontal line is circumscribed to a virtual upper surface of the reduced-diameter portion, which is a virtual end face on the tufting surface side of the inner space of the reduced-diameter portion.

[0039] That is, since the horizontal line is circumscribed to the virtual upper surface of the reduced-diameter portion, it will not enter and be inserted into the reduced-diameter portion any further. Therefore, it is not necessary to apply a greater pressure to fit the horizontal line into the reduced-diameter portion with an inner diameter smaller than the opening diameter on the tufting surface, and the toothbrush of the present invention can be easily manufactured.

[0040] (9) Further, the inner space of the tufting hole may be formed in a substantially cylindrical shape, and the tuft of bristles may be such that the folded-back portion is inscribed in a virtual bottom surface of the tufting hole, which is a virtual end face on the back side of the substantially cylindrical shape.

[0041] That is, since the folded-back portion of the tuft of bristles is inscribed in the virtual bottom surface of the tufting hole, it will not protrude further to the back side. Therefore, even when the tuft of bristles is implanted in a state where the back side of the head portion is in contact with a flat surface such as a workbench, the toothbrush of the present invention will not have the protruding portion interfere with the flat surface as described above. Thus, the toothbrush can be easily manufactured.

[0042] (10) The present invention provides a method for manufacturing a toothbrush, which includes a preparation step including a toothbrush preparation step of preparing a toothbrush having a head portion with a penetrating tufting hole, and a planting step of folding a tuft of a plurality of bristles in half by applying a horizontal line, and inserting the tuft of bristles in the folded state and the horizontal line together from one opening of the tufting hole with the folded-back portion, which is the portion to be folded in half, at the front, and pushing them in until the folded-back portion is exposed at the other opening of the tufting hole.

[0043] That is, according to the method for manufacturing a toothbrush of the present invention, since the tuft is exposed at the other opening, it is used for cleaning in the oral cavity, and when cleaning, by applying a water-absorbing material such as cloth, cotton, or paper to the exposed tuft, moisture such as saliva, chemical solution, running water, and cleaning water can be wiped off. By removing the moisture in this way, the toothbrush can be kept clean.

[0044] (11) Further, before the implanting step, it includes an auxiliary tool preparation step which is a step of preparing a flat wire pressing-in auxiliary tool provided with a concave recessed portion on a plane. The implanting step may include a step of mounting the flat wire insertion auxiliary tool on the other opening side of the head portion so that the recessed portion overlaps the other opening.

[0045] That is, in the method for manufacturing a toothbrush of the present invention, since the recessed portion of the flat wire pressing-in auxiliary tool overlaps the other opening of the tuft insertion hole, the folded-back portion protruding from the other opening can be inserted into the recessed portion. Thereby, when placing the toothbrush on a plane such as a workbench or a device through the flat wire pressing-in auxiliary tool and pushing the tuft and the flat wire into the tuft insertion hole, such a workbench or the like does not interfere with the protrusion of the folded-back portion, and the manufacturing can be carried out efficiently.

[0046] (12) Further, the implanting step may include a step of inserting and fitting the flat wire until the folded-back portion abuts against the bottom of the recessed portion.

[0047] That is, since the folded-back portion of the tuft contacts the bottom of the recessed portion of the flat-line pushing-in auxiliary tool, the length by which the folded-back portion protrudes from the other opening can be regulated by the depth of the recessed portion. Thereby, the protruding length can be set to a length sufficient for wiping off moisture such as saliva, chemical liquid, running water, and washing water with a water-absorbing material such as cloth, cotton, or paper, and can also be set to a length not too long for purposes such as work, use, storage, and aesthetics. Moreover, due to the large friction between the flat line and the groove, the long straight portion, and the strong adhesion of the tuft to the inner wall, even when the plate thickness of the head portion is small, the tuft can remain more securely in the implanted position and cannot fall out. Thus, a toothbrush can be manufactured that can keep clean by removing the moisture and can be used for a long time.

[0048] (13) Also, in the toothbrush preparation step, as the toothbrush, a toothbrush having a reduced-diameter portion with an inner diameter smaller than the opening diameter at the one opening may be prepared, and in the implantation step, the folded-back portion may be pushed in so as to contact the reduced-diameter portion.

[0049] That is, when implanting the bristles, since the folded-back portion is pushed in so as to contact the reduced-diameter portion, the tuft is blocked by the reduced-diameter portion and cannot be pushed further toward the other opening side. Therefore, by the manufacturing method of the toothbrush of the present invention, the tuft can be implanted to a predetermined depth, and the toothbrush can be easily manufactured. Also, during use, the tuft does not come out to the back side, and the bristles do not fall out from 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 keep clean by removing the moisture that tends to accumulate in the bristles on the back side of the head portion, and a method for manufacturing the toothbrush. Also, by reducing the plate thickness of the head portion, it is possible to provide a toothbrush that is easy to clean the oral cavity and a method for manufacturing the toothbrush.

Brief Description of the Drawings

[0051]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

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Figure 16

Figure 17

Figure 18

Figure 19

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

[0053] The head portion 2 of the toothbrush 1 has a tufting surface 2a, and a plurality of tufting holes 3, which are round holes, are formed in the tufting surface 2a. Each tufting hole 3 is regularly arranged as shown in the example of FIG. 1(a). The tufting hole 3 penetrates from the tufting surface 2a to the back surface 2b, which is the surface on the opposite side of the tufting surface 2a with respect to the head portion 2, as shown in FIGS. 2(a) and 2(b). FIG. 3 shows the toothbrush 1 in a state before the tufts 4 are tufted, similar to FIG. 1(a), and is a perspective view showing the toothbrush 1 obliquely from the side. The toothbrush 1 is formed of a synthetic resin such as saturated polyester (PET), polypropylene (PP), or polyacetal resin (POM).

[0054] A plurality of tufts of bristles 4 for cleaning the oral cavity M such as teeth and gums (not shown) are implanted in each implant hole 3, and each tuft of bristles 4 is formed by bundling a plurality of individual bristles 4a aligned in the longitudinal direction thereof. In FIG. 1(b), which is a view of the toothbrush 1 in FIG. 1(a) as seen from the left side, only one tuft of bristles 4 is shown by a solid line for easy viewing, and the remaining tufts of bristles 4 in a gathered state are shown by a two-dot chain line (imaginary line). The user cleans the oral cavity M using the bristles 4a on the implant surface 2a side.

[0055] FIG. 4 is an explanatory view showing the arrangement of the implant holes 3. The state where the tufts of bristles 4 are gathered is shown by a two-dot chain line as in FIG. 1(b).

[0056] Each tuft of bristles 4 is folded in two, and with the folded-back portion 5, which is the portion where it is folded in two, as the leading end, it is pushed into and implanted in each implant hole 3. FIG. 2(a) is a front partial cross-sectional view of the state where the tuft of bristles 4 is folded in two by a flat line 6 and pushed into the implant hole 3, as seen from the plane direction of the flat surface of the flat line 6. Also, FIG. 2(b) is a right-side partial cross-sectional view of the head portion 2 as seen toward the flat right side surface of the flat line 6. The front partial cross-sectional view is a cross-sectional view including the cross-section of the flat line 6, and the right-side partial cross-sectional view is a cross-sectional view including the longitudinal section of the flat line 6. Hatching is omitted for easy viewing of the reference signs, leader lines, etc. Note that FIG. 1(a) shows the state before the implantation of each tuft of bristles 4 and the driving-in of the flat line 6. Also, the description of the flat line 6 is omitted in FIGS. 1(b) and 4.

[0057] The flat line 6 is formed of a material such as copper or brass and has a hardness such that it can be driven into the synthetic resin head portion 2.

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

[0059] Each tuft 4 includes a straight portion 7 which is a substantially columnar bundle continuous with the planting surface 2a side of the folded-back portion 5. Here, as shown in Fig. 2(a), the straight portion 7 refers to the range from the upper end of the folded-back portion 5 to the planting surface 2a in the vertical direction. Although not shown, the plurality of bristles 4a constituting each tuft 4 are arranged in a curved shape surrounding the lower end 6a of the horizontal line 6 in the front view at the folded-back portion 5, and are arranged in a substantially straight line in the substantially vertical direction at the straight portion 7.

[0060] At this time, since the tuft 4 is pushed into the planting hole 3, the straight portion 7 is in close contact with the planting hole wall 3a which is the inner wall of the planting hole 3.

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

[0062] The horizontal line 6 is arranged such that the lower end 6a of the horizontal line is located above the back surface 2b. That is, the inner space of the planting hole 3 which is a round hole is formed into a substantially columnar planting hole columnar space C, and this planting hole columnar space C has a planting hole virtual bottom surface Cb which is a virtual back surface 2b side end surface. The horizontal line 6 is arranged such that the lower end 6a of the horizontal line is located on the planting surface 2a side with respect to this planting hole virtual bottom surface Cb.

[0063] The horizontal line 6 is driven downward and inserted from the entrance of the planting hole 3, and the edge 6b, 6b of the two sides facing each other in the front-rear direction advances to the middle of the planting hole 3 so as to draw two axial grooves 2c, 2c on the inner peripheral surface in the planting hole 3. However, since the two grooves 2c, 2c are shallow and the width of the grooves 2c, 2c is narrow, even when the horizontal line 6 attempts to return upward in the planting hole 3, a frictional force in the axial direction of the planting hole 3 is generated between the edge 6b, 6b of the two sides and the grooves 2c, 2c. As a result, each bristle 4a maintains the planted state without being removed from the planting hole 3.

[0064] As described above, since the toothbrush 1 exposes the tuft 4 on the back surface 2b side, the toothbrush 1 is used for cleaning in the oral cavity M. Also, when cleaning, by applying a water-absorbing material such as cloth, cotton, or paper to the exposed tuft 4, moisture such as saliva, chemical solution, running water, and cleaning water can be wiped off. By removing the moisture in this way, the toothbrush 1 can be kept clean.

[0065] Also, when the tuft 4 contacts the implant hole wall 3a, the folded-back portion 5 does not contact the implant hole wall 3a, while the tuft 4 contacts the implant hole wall 3a at the straight portion 7. Even if an external force tries to push the tuft 4 out of the implant hole 3 upward, a frictional force is generated between the tuft 4 and the implant hole wall 3a in the axial direction of the implant hole 3 at the straight portion 7, causing the tuft 4 to stay.

[0066] And, since the folded-back portion 5 of the toothbrush 1 of the present invention is exposed from the head portion 2 on the back surface 2b side, the area of contact between the straight portion 7 and the implant hole wall 3a is larger compared to a toothbrush where such exposure does not occur. Therefore, the frictional force is relatively large, and the tuft 4 can surely stay at the implanted position.

[0067] Moreover, compared to a toothbrush where there is no exposure, the depth at which the flat wire 6 can be inserted is larger. Therefore, the flat wire 6 can be pushed in deeper, and the friction between the edge portions 6b, 6b of both sides and the respective grooves 2c, 2c is large.

[0068] Furthermore, by configuring the lower end 6a of the flat wire to be located on the implant surface 2a side rather than the virtual bottom surface Cb of the implant hole, the flat wire 6 does not protrude downward beyond the virtual bottom surface Cb of the implant hole. Therefore, it is possible to prevent an accident where the flat wire 6 protrudes from the head portion 2 and damages the user's oral cavity M.

[0069] [Manufacturing method] In FIG. 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 toothbrush 1 of the present invention includes these steps in the order of a preparation step S1010 and a planting step S1020.

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

[0072] On the other hand, in the tool preparation step S1012, a flat wire pressing-in auxiliary tool 8 having a plurality of concave recesses 9 provided in a flat head portion receiving surface 8a as shown in the front partial cross-sectional end view of FIG. 6 is prepared. In the flat wire pressing-in auxiliary tool 8, each recess 9 opens upward in the figure.

[0073] Each recess 9 forms a substantially circular shape when viewed from the head portion receiving surface 8a, and the diameter of the recess edge 9a, which is the boundary with the flat portion of the head portion receiving surface 8a, matches the diameter of each implanting hole 3. The arrangement of each recess 9 in the flat wire pressing-in auxiliary tool 8 matches the arrangement of the implanting holes 3 in the head portion 2 in the left-right direction and the front-back direction. The flat wire pressing-in auxiliary tool 8 is made of a material harder than the flat wire 6. For example, when the flat wire 6 is formed of brass, it is made of a metal harder than brass.

[0074] The planting step S1020 includes these steps in the order of a tool mounting step S1021, a pressing-in step S1022, and a tool removing step S1023.

[0075] In the tool mounting step S1021, the flat wire pressing-in auxiliary tool 8 is mounted on the head portion 2 so that the back surface 2b of the head portion 2 and the head portion receiving surface 8a of the flat wire pressing-in auxiliary tool 8 come into contact. At this time, the back surface 2b and the head portion receiving surface 8a are arranged such that the back surface side opening edge 3b, which is the boundary between the plane of the back surface 2b and the back surface 2b side opening of each implanting hole 3, and the recess edge 9a overlap. Thereby, each implanting hole 3 and the corresponding each recess 9 communicate with each other.

[0076] In the pressing step S1022, the tuft 4 formed by bundling a plurality of bristles 4a is bent in half by applying a flat wire 6, and the tuft 4 in the double-folded state and the flat wire 6 are both inserted into the implantation surface 2a side opening of the implantation hole 3 with the folded-back portion 5, which is the portion to be double-folded, at the front, and the folded-back portion 5 is pushed in through the back surface 2b side opening of the implantation hole 3 until it protrudes from the head portion 2.

[0077] At this time, the flat wire 6 is driven downward, and the edges 6b, 6b on both sides proceed to the middle of the implantation hole 3 so as to draw two ribs of grooves 2c, 2c. Also, FIG. 7 shows a state where the flat wire pressing aid 8 is attached to the head portion 2, and the tip of the folded-back portion 5 proceeds to the inside of the recessed portion 9 as shown in this FIG. 7.

[0078] In the aid removal step S1023, the flat wire pressing aid 8 is removed from the head portion 2 so that the head portion receiving surface 8a is separated from the back surface 2b. After passing through the aid removal step S1023, the toothbrush 1 in which the bristles 4a are implanted so as to expose the tuft 4 from the head portion 2 on the back surface 2b side is completed.

[0079] In this way, the toothbrush 1 cleans the inside of the oral cavity M using the bristles 4a on the implantation surface 2a side, and since the tuft 4 protrudes and is exposed from the head portion 2 on the back surface 2b side, when a water-absorbing material such as cloth, cotton, or paper is applied to the protruding tuft 4 during washing, moisture such as saliva, chemical solution, running water, and washing water can be wiped off. By removing the moisture in this way, the toothbrush 1 can be kept clean.

[0080] Also, since the recessed portion 9 of the flat wire pressing aid 8 overlaps with the back surface 2b side opening of the implantation hole 3 and the implantation hole 3 and the recessed portion 9 communicate with each other, the folded-back portion 5 protruding from the back surface 2b side opening can be inserted into the recessed portion 9. Thereby, when the toothbrush 1 is placed on a plane such as a workbench or a device via the flat wire pressing aid 8 and the tuft 4 and the flat wire 6 are pushed into the implantation hole 3, such a workbench or the like does not obstruct the protrusion of the folded-back portion 5, and the toothbrush 1 can be efficiently manufactured.

[0081] [Second Embodiment] Figs. 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 tufting surface 102a, and a plurality of tufting holes 103, which are round holes, are formed in the tufting surface 102a. As shown in Figs. 8(a) and 8(b), the tufting holes 103 penetrate from the tufting surface 102a to the back surface 102b, which is the surface on the side opposite to the tufting surface 102a with respect to the head portion 102.

[0083] The tufting hole 103 has a reduced-diameter portion 103c whose inner diameter is smaller than the opening diameter on the tufting surface 102a. The upper end of the reduced-diameter portion 103c forms an annular step, and a step edge 103d, which is the edge inside this step, is formed. The step edge 103d draws a circle in plan view. And the inner space occupied by the reduced-diameter portion 103c forms a substantially cylindrical reduced-diameter portion cylindrical space E between the step edge 103d and the back surface side opening edge 103b.

[0084] Figs. 9(a) and 9(b) show the entire tufting hole 103 and schematically represent the front cross-sectional views of the tufting hole cylindrical space C and the reduced-diameter portion cylindrical space E, respectively. Fig. 9(a) shows the tufting hole cylindrical space C, and the hatched portion in Fig. 9(b) shows the reduced-diameter portion cylindrical space E. Here, the tufting hole cylindrical space C has a tufting hole virtual bottom surface Cb, which is the virtual back surface 102b side end surface. The reduced-diameter portion cylindrical space E has a reduced-diameter portion virtual upper surface Ea, which is the virtual tufting surface 102a side end surface, and a reduced-diameter portion virtual bottom surface Eb, which is the virtual back surface 102b side end surface.

[0085] Since these virtual bottom surfaces Cb and Eb are located at the lowermost part of the tufting hole 103 because the reduced-diameter portion 103c is provided offset toward the back surface 102b side of the tufting hole 103. In other words, since the tufting hole cylindrical space C and the reduced-diameter portion cylindrical space E coincide in the reduced-diameter portion 103c located closer to the back surface 102b, the tufting hole virtual bottom surface Cb and the reduced-diameter portion virtual bottom surface Eb coincide.

[0086] As shown in FIGS. 8(a) and 8(b), the flat line 106 is arranged such that the lower end 106a of the flat line is located on the side of the implanting surface 102a rather than the virtual bottom surface Cb of the implanting hole. Also, the flat line 106 is arranged such that the lower end 106a of the flat line circumscribes the virtual upper surface Ea of the reduced-diameter portion and contacts the cylindrical space E of the reduced-diameter portion downward. Then, the pushed-in folded portion 105 abuts against the stepped edge 103d, and the implantation of the tuft 104 is completed.

[0087] Other configurations are common to the first embodiment.

[0088] With such a configuration, when implanting the bristles, the folded portion 105 of the tuft 104 of the toothbrush 101 is blocked by the stepped edge 103d of the reduced-diameter portion 103c and is not pushed into the back surface 102b side unnecessarily. Therefore, the tuft 104 is implanted to a predetermined depth and can be easily manufactured. Also, during use, the tuft 104 does not come out to the back surface 102b side, and the bristle 104a does not fall out of the implanting hole 103, so this toothbrush can be used for a long time.

[0089] Also, since the reduced-diameter portion 103c is provided offset to the back surface 102b side of the implanting hole 103 and the pushing depth of the tuft 104 is regulated by this reduced-diameter portion 103c, the tuft 104 is pushed in deeper compared to the case where the reduced-diameter portion 103c is provided closer to the implanting surface 102a. Therefore, the area of the straight portion 107 that is in close contact with the implanting hole wall 103a is large, and the frictional force generated between the straight portion 107 and the implanting hole wall 103a is large. As a result, the risk of the tuft 104 coming out from the implanting surface 102a side is small.

[0090] Furthermore, since the flat line 106 can be inserted deeply, the frictional force generated between the flat line 106 and the grooves 102c, 102c in the implanting hole 103 is large, and the flat line 106 that suppresses the tuft 104 is prevented from returning to the implanting surface 102a side. Also because of this, the risk of the tuft 104 coming out from the implanting surface 102a side is small.

[0091] And since the flat line 106 is circumscribed around the virtual upper surface Ea of the reduced-diameter portion, it will not enter and be inserted further into the reduced-diameter portion 103c. Therefore, it is not necessary to apply a greater pressure to fit the flat line 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 line 106 is not circumscribed around 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 line 106 will be pushed deeper. From this also, the tuft 104 has a small risk of being pulled out from the implanting surface 102a side.

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

[0093] The manufacturing method S1100 of the toothbrush 101 of the present invention includes these steps in the order of a preparation step S1110 and a planting step S1120.

[0094] The preparation step S1110 includes a toothbrush preparation step S1111 and an accessory preparation step S1112. In the toothbrush preparation step S1111, the toothbrush 101 is prepared, and implanting holes 103 are provided in the head portion 102 of the toothbrush 101. The toothbrush 101 has the head portion 102 and a handle portion continuous with the head portion 102 formed, for example, by injection molding.

[0095] At this time, the implanting hole 103 has a reduced-diameter portion 103c whose inner diameter is smaller than the opening diameter on the implanting surface 102a. The reduced-diameter portion 103c forms an annular step at the upper end and forms a step edge 103d which is the edge inside this step. The step edge 103d draws a circle in plan view.

[0096] Next, the planting step S1120 includes these steps in the order of an accessory mounting step S1121, a pushing step S1122, and an accessory removing step S1123.

[0097] In the pushing step S1122, the tuft 104 formed by bundling a plurality of bristles 104a is bent in half by applying a flat line 106, and both the tuft 104 in the folded state and the flat line 106 are inserted into the planting surface 102a side opening of the implanting hole 103 with the folded-back portion 105, which is the portion to be folded in half, at the head, and the folded-back portion 105 is pushed in through the back surface 102b side opening of the implanting hole 103 until it protrudes from the head portion 102.

[0098] The pushing step S1122 includes a folded-back portion abutting step S1122a. By the folded-back portion abutting step S1122a, as a result of the tuft 104 advancing through the implanting hole 103, the folded-back portion 105 abuts against the stepped edge 103d, and the planting is completed by being obstructed by this stepped edge 103d and not advancing any further.

[0099] The other processes and steps are common to the method for manufacturing a toothbrush in the first embodiment.

[0100] By such a manufacturing method, when implanting the bristles, since the folded-back portion 105 is pushed in so as to abut against the reduced-diameter portion 103c, the tuft 104 is obstructed by the reduced-diameter portion 103c and is not pushed further toward the back surface 102b side. Therefore, the tuft 104 is implanted at a predetermined depth, and the toothbrush 101 can be easily manufactured. Also, even during use, the tuft 104 does not come out toward the back surface 102b side, and the bristles 104a do not come out of the implanting hole 103, so that this toothbrush 101 can be used for a long time.

[0101] [Third Embodiment] FIGS. 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 planting surface 112a, and a plurality of implanting holes 113, which are round holes, are formed in the planting surface 112a. The implanting holes 113 penetrate from the planting surface 112a to the back surface 112b, which is the surface on the side opposite to the planting surface 112a with respect to the head portion 112, as shown in FIGS. 11(a) and 11(b).

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

[0104] The tuft of hair 114 has a folded-back portion 115 that is pushed into the hair implanting hole cylindrical space C and is inscribed in the virtual bottom surface Cb of the hair implanting hole. Thus, since the toothbrush 111 exposes the tuft of hair 114 on the back surface 112b side, the toothbrush 111 is used for cleaning in the oral cavity M, and when cleaning, by applying a water-absorbing material such as cloth, cotton, or paper to the exposed tuft of hair 114, moisture such as saliva, medicinal liquid, running water, and cleaning water can be wiped off. By removing moisture in this way, the toothbrush 111 can be kept clean.

[0105] Other configurations are common to the second embodiment.

[0106] With such a configuration, the toothbrush 111 has the folded-back portion 115 inscribed in the virtual bottom surface Cb of the hair implanting hole, and the tuft of hair 114 does not protrude further to the back surface 112b side. Therefore, even when the tuft of hair 114 is implanted in a state where the back surface 112b side of the head portion 112 is in contact with a flat surface such as a workbench, the protruding portion of the toothbrush 111 does not interfere with the flat surface. Thus, the toothbrush 111 can be easily manufactured.

[0107] [Manufacturing Method] In FIG. 12, S1200 illustrates the manufacturing method of the toothbrush in the third embodiment of the present invention.

[0108] The manufacturing method S1200 of the toothbrush 111 of the present invention includes these steps in the order of a preparation step S1210 and a planting step S1220. The preparation step S1210 includes a toothbrush preparation step S1211. Further, the planting step S1220 includes a pressing step S1222. The pressing step 1222 includes a folded portion abutting step S1222a. In the folded portion abutting step S1222a, the folded portion 115 abuts against the stepped edge 113d and is inscribed in the virtual bottom surface Cb of the implanting hole.

[0109] These steps and steps are common to the manufacturing method of the toothbrush in the second embodiment. Note that since the folded portion 115 of the toothbrush 111 in the present embodiment does not protrude from the back surface 112b side, it is not always necessary to use the flat line pressing aid 8 used in the second embodiment. Therefore, in the manufacturing method of the present embodiment, the auxiliary tool preparation step S1112, the auxiliary tool mounting step S1121, and the auxiliary tool removal step S1123 included in the manufacturing method of the second embodiment are not always required.

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

[0111] The head portion 12 of the toothbrush 11 has a hair implanting surface 12a, and a plurality of implanting holes 13, which are round holes, are formed in the hair implanting surface 12a. The implanting holes 13 penetrate from the hair implanting surface 12a to the back surface 12b as shown in Figs. 13(a) and (b). A plurality of tufts 14 are implanted in each implanting hole 13, and each tuft 14 is formed by bundling individual bristles 14a. Each tuft 14 is folded in two, and with the folded portion 15, which is this two-folded portion, at the head, it is pushed into and planted in each implanting hole 13. Figs. 13(a) and (b) are a front partial cross-sectional view and a right side partial cross-sectional view, respectively, showing the state where the tuft 14 is folded in two by a flat line 16 and pushed into the implanting hole 13.

[0112] Each tuft 14 includes a straight portion 17 which is a substantially columnar bundle continuous with the implanting surface 12a side of the folded-back portion 15. Since the tuft 14 is pushed into the implanting hole 13, the straight portion 17 is in close contact with the implanting hole wall 13a which is the inner wall of the implanting hole 13.

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

[0114] The flat wire 16 is driven downward and proceeds until the edge portions 16b, 16b on both sides approach the lower end of the implanting hole 13 so as to draw two ribs of grooves 12c, 12c. Then, the flat wire 16 is arranged such that the lower end 16a of the flat wire is located above the back surface 12b. That is, the flat wire 16 is arranged such that the lower end 16a of the flat wire is located on the implanting surface 12a side with respect to the virtual bottom surface Cb of the implanting hole cylindrical space C of the implanting hole 13.

[0115] The lower end of the straight portion 17 coincides with the position of the back surface 12b in the vertical direction. That is, the thickness of the head portion 12 and the height of the straight portion 17 coincide, and the entire implanting hole wall 13a is in close contact with the straight portion 17.

[0116] FIG. 14 shows a state where the flat wire pushing aid 8 is attached to the head portion 12, and the folded-back portion 15 proceeds to the inside of the recessed portion 9 as shown in FIG. 14.

[0117] Other configurations are common to the first embodiment.

[0118] Since the entire folded-back portion 15 of the toothbrush 11 of the present invention protrudes and is exposed from the head portion 12 on the back surface 12b side, the straight portion 17 is in close contact with the entire implanting hole wall 13a. Therefore, the area where the tuft 14 contacts the implanting hole wall 13a is larger, the frictional force is large, and the tuft 14 can surely stay at the implanted position.

[0119] [Example] FIG. 15 shows the results of measuring the hair retention strength when the hair bundle 14 was pulled out from the hair implantation hole 13 when the bristle 14a was implanted in the hair implantation hole 13 using the flat line 16 as shown in FIG. 13 in the toothbrush 11. The bristle 14a used had a nylon material, a thickness of 6 mil (mils), and a length of 33 mm. The toothbrush 11 had hair implantation holes 13 with diameters of 1.0 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, and 2.0 mm, respectively, and the head portion 12 represented by the symbol t in FIG. 4 had a plate thickness of 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, and 5.0 mm, respectively, which were prepared. For each hair implantation hole 13 with a respective diameter, the number of bristles 14a constituting each hair bundle 14 was 22 by folding 11 bristles 14a for 1.0 mm, 40 in total for 1.2 mm, 52 in total for 1.4 mm, 72 in total for 1.6 mm, 90 in total for 1.8 mm, and 114 in total for 2.0 mm.

[0120] When implanting the hair bundle 14, the flat line pushing-in auxiliary tool 8 was used according to the toothbrush manufacturing method S1000.

[0121] The hair retention strength test was performed using a tensile testing machine in accordance with the above-mentioned explanation of 'Toothbrush JIS S 3016 - 1995'. The pulling-out speed in the strength test using the tensile testing machine was set to 20 mm / min.

[0122] The table in FIG. 15 shows the average value of the hair retention strength (N) when the bristles 14a of the above-mentioned number were implanted and the strength test was performed three times each when each row represents the plate thickness (mm) of each head portion 12 and each column represents the respective hair implantation hole diameter (mm).

[0123] FIG. 16 shows graphs for each case of the diameter of each implanting hole 13 when the hair retention strength (N) is shown on the vertical axis and the plate thickness (mm) of the head portion 12 is shown on the horizontal axis. As shown by the respective numerical values in FIG. 15 and the graphs in FIG. 16, the hair retention strength in all cases where the plate thickness of the head portion 12 is 1.5 mm or more and 5.0 mm or less is 15.0 N or more, and it was confirmed that the value is larger than 8 N which is the specified value based on the resolution of the Standardization Council of the Japanese Industrial Standards Committee dated June 1, 1990. Therefore, the toothbrush 11 of the present invention can set the plate thickness of the head portion 12 to be 1.5 mm or more and 5.0 mm or less.

[0124] On the other hand, among the above graphs, when the diameter of the implanting hole 13 is 1.0 mm, the hair retention strength peaks when the plate thickness of the head portion 12 is 4.0 mm, and it was found that the hair retention strength decreases as the plate thickness increases when the plate thickness is 4.0 mm or more. Further, it was found that the minimum limit size of the plate thickness of the head portion 12 is 1.5 mm in terms of the processing of forming the implanting hole 13 with the above dimensions and driving in the flat wire 16. As described above, when implanting the hair bundle 14 into the straight hair hole 13 with the above dimensions, it is more preferable that the plate thickness of the head portion 12 is 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 hair retention strength as a toothbrush by forming the plate thickness of the head portion 12 in the range of 1.5 mm or more and less than 4.0 mm.

[0126] Further, even if the plate thickness of the head portion 12 is extremely thin such as in the range of 1.5 mm or more and less than 2.0 mm, the hair retention strength exceeds 15.0 N. Furthermore, even if the plate thickness is thin such as in the range of 2.0 mm or more and less than 2.5 mm, the hair retention strength exceeds 25.0 N.

[0127] As described above, by reducing the plate thickness of the head portion 12, the toothbrush 11 can more easily reach the back teeth and is easy to clean the oral cavity. Therefore, the toothbrush 11 of the present invention can easily clean the oral cavity, and moreover, the bristles 14a are difficult to be pulled out and can be used for a long time.

[0128] [Embodiment 5] Figures 17 to 19 illustrate the fifth embodiment of the present invention. In the figures, 21 is a toothbrush.

[0129] The head portion 22 of the toothbrush 21 has a tufting surface 22a, and a plurality of tufting holes 23, which are round holes, are formed in the tufting surface 22a. The tufting holes 23 penetrate from the tufting surface 22a to the back surface 22b as shown in FIGS. 17(a) and 17(b). A plurality of tuft bundles 24 are implanted in each of the tufting holes 23, and each tuft bundle 24 is formed by bundling individual bristles 24a. Each tuft bundle 24 is folded in two, and with the folded-back portion 25, which is this two-folded portion, as the leading end, it is pushed into each of the tufting holes 23 and implanted. FIGS. 17(a) and 17(b) are a front partial cross-sectional view and a right-side partial cross-sectional view, respectively, showing the state where the tuft bundle 24 is folded in two by a flat line 26 and pushed into the tufting hole 23.

[0130] Each tuft bundle 24 includes a straight portion 27, which is a substantially columnar bundle continuous with the tufting surface 22a side of the folded-back portion 25. Since the tuft bundle 24 is pushed into the tufting hole 23, the straight portion 27 is in close contact with the tufting hole wall 23a, which is the inner wall of the tufting hole 23.

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

[0132] The flat line 26 is driven downward, and the edge ends 26b, 26b of both sides draw two ribs of grooves 22c, 22c, and the flat line lower end 26a advances until it reaches the back surface 22b of the head portion 22. That is, the flat line 26 is arranged such that the flat line lower end 26a is inscribed in the virtual bottom surface Cb of the tufting hole cylindrical space C of the tufting hole 23 and is in contact with the virtual bottom surface Cb of the tufting hole in a downward direction. Also, the length of the two ribs of grooves 22c, 22c coincides with the thickness of the head portion 22.

[0133] The straight portion 27 has its lower end coinciding with the position of the back surface 22b in the vertical direction. That is, the thickness of the head portion 22 and the height of the straight portion 27 coincide, and the entire implanting hole wall 23a is in close contact with the straight portion 27.

[0134] Other configurations are common to the fourth embodiment.

[0135] In the toothbrush 11 of the present invention, since the straight line 26 is disposed at the lowermost side of the implanting hole 23, the tuft 24 is pressed radially outward at the deepest position of the implanting hole 23. Therefore, the tuft 24 is more strongly adhered to the implanting hole wall 23a. As a result, the tuft 24 can stay in the implanted position more reliably. Also, the two grooves 22c, 22c are the longest, and the friction between the two side edges 26b, 26b and the respective grooves 22c, 22c is greater.

[0136] Furthermore, since the lower end 26a of the straight line is configured to be inscribed in the virtual bottom surface Cb of the implanting hole, the straight line 26 does not protrude downward beyond the virtual bottom surface Cb of the implanting hole. Therefore, it is possible to prevent an accident in which the straight line 26 protrudes from the head portion 22 and damages the inside of the user's oral cavity M.

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

[0138] The pushing step S2022 of the toothbrush manufacturing method S2000 includes a straight line bottoming step S2022a of inserting and fitting the straight line 26 until each folded portion 25 abuts against the bottom portion 9b of the recessed portion 9 at the bottom of the recessed portion 9 into which it is inserted. At this time, the straight line pushing aid 8 shown in FIG. 6 is configured such that the depth of the recessed portion 9 coincides with the height of each folded portion 25 in the vertical direction. Therefore, the straight line 26 stops entering the downward implanting hole 23 when the lower end of each folded portion 25 hits the bottom portion 9b.

[0139] In addition, since the flat wire insertion assist tool 8 is made of a material harder than the flat wire 26, even if an attempt is made to further push in the flat wire 26, the lower end 26a of the flat wire will not be buried in the head portion receiving surface 8a.

[0140] FIG. 19 shows a state in which the flat wire insertion assist tool 8 is attached to the head portion 22, the folded-back portion 25 is accommodated inside the recessed portion 9, and the lower end of the folded-back portion 25 abuts against the bottom portion 9b of the recess.

[0141] The other processes and steps are common to the method for manufacturing a toothbrush in the fourth embodiment.

[0142] In this way, the depth of the recessed portion 9 can regulate the length by which the folded-back portion 25 protrudes from the opening on the back surface 22b side. As a result, the protruding length can be set to a length sufficient for wiping off moisture such as saliva, chemical solution, running water, and washing water with a water-absorbing material such as cloth, cotton, or paper, and can also be set to a length that is not too long for work, use, storage, aesthetics, etc. In this way, it is possible to manufacture the toothbrush 21 that can be kept clean by removing the moisture.

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

[0144] For example, the hair implantation holes do not have to be round holes, and may be formed as elliptical holes or square holes as long as the bristles can be bundled and implanted in a tuft state.

[0145] Also, the number of hair implantation holes provided in the head portion does not have to be plural, and a single hair implantation hole may be used. Accordingly, the implanted tuft of bristles may also be single. Furthermore, the recessed portion provided in the flat wire insertion assist tool may also be single.

[0146] When the folded-back portion protrudes and is exposed from the head portion, for the flat wire insertion assist tool, as long as it does not interfere with the protrusion of the folded-back portion from the head portion, the edge of the opening on the back surface side does not have to have the same diameter as the edge of the recess, and may have a smaller diameter or a larger diameter than the edge of the recess.

[0147] The material of the flat wire does not necessarily have to be metal, and it may be, for example, plastic as long as it has a hardness sufficient to be driven into the head portion.

[0148] When the folded-back portion protrudes from the head portion and is exposed, when driving in the flat wire, if it does not interfere with the protrusion of the folded-back portion from the head portion, without using a flat wire pushing-in auxiliary tool, for example, the head portion can be supported in the air with one hand, and the tuft can be supported and pushed in with the other hand.

[0149] When implanting the tuft into the head portion, instead of using a flat wire, for example, the bristles can be welded and fixed to the head portion.

[0150] Even if the upper end of the flat wire does not necessarily circumscribe the virtual upper surface of the reduced-diameter portion, as long as the flat wire can be pushed in deep enough so that the tuft does not fall out from the implanting surface side, it may be located above the virtual upper surface of the reduced-diameter portion.

[0151] Even if the reduced-diameter portion is not provided offset to the back side, as long as the flat wire can be pushed in deep enough so that the tuft does not fall out from the implanting surface side, it may be provided such that the virtual bottom surface of the reduced-diameter portion is located above the virtual bottom surface of the implanting hole.

Industrial Applicability

[0152] The present invention can be used in a method for manufacturing a toothbrush including a toothbrush preparation step of preparing a toothbrush having implanting holes penetrating the head portion and a toothbrush having a head portion provided with implanting holes penetrating therethrough.

Explanation of Reference Numerals

[0153] 1, 11, 21, 101, 111 Toothbrush 2, 12, 22, 102, 112 Head portion 3, 13, 23, 103, 113 Implanting hole 103c, 113c Reduced-diameter portion 4, 14, 24, 104, 114 Tuft 4a, 14a, 24a, 104a, 114a Bristles 5, 15, 25, 105, 115 folding part 6, 16, 26, 106, 116 flat line 7, 17, 27, 107, 117 straight part 8 flat line pressing auxiliary tool 9 recessed part C implanting hole cylindrical space (substantially cylindrical) Cb virtual bottom surface of implanting hole E reduced diameter part cylindrical space Ea virtual upper surface of reduced diameter part Eb virtual bottom surface of reduced diameter part 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 implanting process S1021, S1121, S2021 auxiliary tool mounting step S1022, S1122, S1222, S2022 pressing step S1023, S1123, S2023 auxiliary tool removing step

Claims

1. A toothbrush comprising bristles and a head portion for implanting a tuft of a plurality of the bristles, the head portion having an implanting surface with implanting holes formed therein, the tuft being folded in two and implanted in the implanting holes with the folded-back portion, which is the portion where the tuft is folded in two, at the head, wherein the implanting holes penetrate through the back surface of the head portion on the side opposite to the implanting surface, and the tuft has the folded-back portion exposed at the opening on the back surface side. A toothbrush characterized by the above.

2. The toothbrush having a flat wire driven into the implanting holes, wherein the tuft is folded in two by the flat wire and pushed into the implanting holes. The toothbrush according to claim 1, characterized by the above.

3. wherein the inner space of the implanting holes is formed in a substantially cylindrical shape, and the flat wire is disposed such that the lower end of the flat wire, which is one side on the back surface side, is positioned closer to the implanting surface side than the virtual bottom surface of the implanting holes, which is the virtual back surface side end surface of the substantially cylindrical shape. The toothbrush according to claim 2, characterized by the above.

4. wherein the inner space of the implanting holes is formed in a substantially cylindrical shape, and the flat wire is disposed such that the lower end of the flat wire, which is one side on the back surface side, is inscribed in the virtual bottom surface of the implanting holes, which is the virtual back surface side end surface of the substantially cylindrical shape. The toothbrush according to claim 2, characterized by the above.

5. The thickness of the head portion is formed in the range of 1.5 mm or more and less than 4.0 mm. The toothbrush according to claim 3 or 4, characterized by the above.

6. The implanting holes have a reduced-diameter portion with an inner diameter smaller than the opening diameter on the implanting surface. The toothbrush according to claim 3, characterized by the above.

7. In the reduced-diameter portion, the virtual bottom surface of the inner space of the reduced-diameter portion coincides with the virtual bottom surface of the implanting holes. The toothbrush according to claim 6, characterized by the above.

8. The flat wire is disposed such that the lower end of the flat wire is circumscribed to the virtual upper surface of the reduced-diameter portion, which is the virtual implanting surface side end surface of the inner space of the reduced-diameter portion. The toothbrush according to claim 7, characterized by the above.

9. wherein the inner space of the implanting holes is formed in a substantially cylindrical shape, and the tuft has the folded-back portion inscribed in the virtual bottom surface of the implanting holes, which is the virtual back surface side end surface of the substantially cylindrical shape. The toothbrush according to any one of claims 1 to 8, characterized by the above.

10. A preparation process including a toothbrush preparation process for preparing a toothbrush having a head portion with a penetrating implanting hole. A planting process, which includes folding a tuft of multiple bristles in half by applying a flat line, and inserting both the folded tuft and the flat line into one opening of the implanting hole with the folded-back part, which is the folding part, at the front, and pushing them in until the folded-back part is exposed at the other opening of the implanting hole. A method for manufacturing a toothbrush, characterized by the above.

11. Including an auxiliary tool preparation process, which is a process of preparing a flat line pushing-in auxiliary tool with a concave recessed part on a plane before the planting process. The planting process includes a step of mounting the flat line insertion auxiliary tool on the other opening side of the head part so that the recessed part overlaps with the other opening. A method for manufacturing a toothbrush according to Claim 10, characterized by the above.

12. The planting process includes a step of inserting the flat line until the folded-back part abuts against the bottom of the recessed part. A method for manufacturing a toothbrush according to Claim 11, characterized by the above.

13. In the toothbrush preparation process, prepare a toothbrush having a reduced-diameter part with an inner diameter smaller than the opening diameter at the one opening as the toothbrush. In the planting process, push in the folded-back part so that it abuts against the reduced-diameter part. A method for manufacturing a toothbrush according to Claim 10, characterized by the above.

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