Toothbrush

Abstract

To provide a toothbrush that can avoid over-brushing and maintain excellent cleanability and operability without reducing the operability and grip performance of the toothbrush.SOLUTION: There is provided a toothbrush in which a relation between differences C1, C2 of a deflection amount satisfies C1<C2. When a position apart by a horizontal distance of 110 mm from an axial center position of a bristle implantation surface is fixed, a distance between a position of a tip of a head portion in a no-load state and a position of the tip of the head portion after 10 seconds when a weight of 150 g is suspended from the axial center position of the bristle implantation surface is defined as d1, a distance between the position of the tip of the head portion in the no-load state and the position of the tip of the head portion after 10 seconds when a weight of 200 g is suspended from the axial center position of the bristle implantation surface is defined as d2, and a distance between the position of the tip of the head portion in the no-load state and the position of the tip of the head portion after 10 seconds when a weight of 250 g is suspended from the axial center position of the bristle implantation surface is defined as d3, a difference between d2 and d1 is defined as a difference C1 of a deflection amount, and a difference between d3 and d2 is defined as a difference C2 of the deflection amount.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a toothbrush including a head portion in which tufts are implanted, a neck portion connected to the head portion, and a handle portion serving as a grip.

Background Art

[0002] When brushing teeth, if overbrushing occurs where excessive brushing pressure is applied, the gums will be damaged. In conventional toothbrushes, in order to suppress this overbrushing, there are those in which the neck portion is made thin and has flexibility, or toothbrushes provided with a bent portion that is more likely to bend than adjacent portions at the neck portion, the handle portion, or the boundary portions thereof (see, for example, Patent Documents 1 and 2).

[0003] However, these toothbrushes that prevent overbrushing may reduce the operability and grip of the toothbrush due to increased flexibility, which may hinder cleaning and toothbrushing operations.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Therefore, in view of the above situation, the problem to be solved by the present invention is to provide a toothbrush that can avoid overbrushing, does not reduce the operability and grip of the toothbrush, and can maintain excellent cleaning performance and operability.

Means for Solving the Problems

[0006] That is, the present invention includes the following inventions.

[0007] (1) A toothbrush comprising a head portion where bristles are implanted, a neck portion connected to the proximal end side of the head portion, and a handle portion serving as a grip connected to the proximal end side of the neck portion, wherein the relationship between the deflection amount differences C1 and C2 below satisfies C1 < C2.

[0008] (Deflection amount differences C1 and C2) With the protruding direction of the bristles facing upward and the bristle-implanting surface of the head portion being horizontal, fix a position 110 mm horizontally away from the axial center position of the bristle-implanting surface toward the proximal end side. The vertical distance between the position of the tip of the head portion in the no-load state and the position of the tip of the head portion 10 seconds after suspending a 150 g weight at the axial center position of the bristle-implanting surface is defined as the deflection amount d1 (mm). The vertical distance between the position of the tip of the head portion in the no-load state and the position of the tip of the head portion 10 seconds after suspending a 200 g weight at the axial center position of the bristle-implanting surface is defined as the deflection amount d2 (mm). The vertical distance between the position of the tip of the head portion in the no-load state and the position of the tip of the head portion 10 seconds after suspending a 250 g weight at the axial center position of the bristle-implanting surface is defined as the deflection amount d3 (mm). When this is done, the difference between d2 and d1 is defined as the deflection amount difference C1 (mm), and the difference between d3 and d2 is defined as the deflection amount difference C2 (mm). In addition, when the horizontal length of the remaining part of the toothbrush on the proximal end side from the fixed position 110 mm horizontally away is less than 20 mm, or when the total length of the toothbrush is less than 110 mm, the fixed position shall be the position 20 mm horizontally away from the proximal end of the toothbrush.

[0009] (2) The toothbrush according to (1), wherein the deflection amount difference C1 is 6 mm or less.

[0010] (3) The toothbrush according to (1) or (2), wherein the sum of the deflection amount differences C1 and C2 is 8 mm or less.

[0011] (4) The toothbrush according to any one of (1) to (3), wherein the difference between the deflection amount differences C1 and C2 is 0.5 mm or more.

[0012] (5) The toothbrush according to any one of (1) to (4), wherein a bent portion that is more bendable than an adjacent portion is provided at the neck portion, the handle portion, or a boundary portion between them. (6) The toothbrush according to any one of (1) to (5), wherein at least a part of the head portion, the neck portion, and the handle portion are integrally formed of the same resin. (7) The toothbrush according to any one of (1) to (6), wherein the width of the narrowest part of the neck portion is 5 mm or less and the thickness is 5 mm or less.

Advantages of the Invention

[0013] According to the toothbrush of the present invention configured as described above, overbrushing can be avoided, and at the same time, the operability and gripability of the toothbrush are not reduced, and excellent cleaning performance and operability can be maintained.

Brief Description of the Drawings

[0014]

Figure 1

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Mode for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0016] As shown in FIGS. 1 to 3, the toothbrush H according to the present invention includes a head portion 1 in which a tuft 10 is implanted, a substantially rod-shaped neck portion 2 connected to the proximal end side of the head portion 1, and a handle portion 3 serving as a grip connected to the proximal end side of the neck portion 2.

[0017] The head portion 1 is preferably integrally formed of a hard synthetic resin such as polypropylene resin, polyethylene terephthalate resin, polyacetal resin, polybutylene terephthalate resin, or polyamide resin together with the neck portion 2. The handle portion 3 may be integrally formed of the same resin as the neck portion 11, or may be composed of a core portion 4 integrally formed with the neck portion 11 and a separately formed covering material 5 covering the core material 4 as in the present embodiment.

[0018] The head portion 1 has a substantially flat hair implanting base 11 from which the tuft 10 projects, and the thickness T1 of the hair implanting base 11 is preferably 4.0 mm or less, more preferably 3.0 mm or less, and even more preferably 2.5 mm or less. This makes it easy for the head portion to reach the deep part (rear teeth) of a narrow gap in the oral cavity. The lower limit value is preferably 2.0 mm or more, and more preferably 2.5 mm or more. If it is thinner than 2.0 mm, the strength cannot be maintained.

[0019] On the hair implanting surface 12, a plurality of bottomed hair implanting holes 13 having a substantially circular cross-section are formed. The opening diameter, depth, number, arrangement form, etc. of the hair implanting holes 13 are not limited in any way in this example. The hair bundle 10 may be implanted by driving it into the hair implanting holes 13 of the hair implanting surface 12 together with a flat wire, or the hair bundle 10 may be erected by a fusion method or an in-mold method without using a flat wire. The material of each filament constituting the hair bundle 10 is not particularly limited, and it may be artificial hair made of a resin material such as nylon, polyester, or polyolefin, or natural hair such as pig hair. In addition, known forms can be widely adopted for the cross-sectional shape, cross-sectional size, etc.

[0020] The neck portion 2 is configured to have a tapered structure in which the width in the front-back and left-right directions gradually narrows toward the tip side. In particular, the portion on the tip side of the central position 2c has a thin neck with a thickness in the front-back direction and a width in the left-right direction both being 5 mm or less, more preferably 4.5 mm or less, and even more preferably 4 mm or less. Thereby, when brushing teeth, the head portion 1 can reach the narrow part of the back teeth, and the cleaning property of the back teeth can be improved.

[0021] The narrow-width portion 2n, which is the portion where the left-right width of the neck portion 2 is the narrowest. In this example, the boundary portion with the head portion 1 is the portion where the front-back thickness is also the smallest, but its cross-sectional shape is set to be substantially quadrangular in cross-section as shown in FIG. 5(a). Here, the substantially quadrangular shape includes a concept including a substantially rectangular or substantially square shape provided with an arcuate chamfered portion at the corner. By configuring the narrow-width portion 2n of the neck portion 2 to have such a substantially quadrangular cross-sectional shape, it is possible to effectively suppress the head portion 1 from greatly wobbling left and right or the tip of the neck portion 2 from being greatly twisted during toothbrushing, and the operability of the toothbrush can be maintained in a good state.

[0022] That is, when the cross-sectional shape is formed into a substantially rectangular shape, deflection corresponding to the load transmitted from the head portion 1 is likely to occur in the front-rear and left-right directions, and is less likely to occur in the diagonal direction. Therefore, it is possible to prevent the deflection from occurring in a direction contrary to the intention of the user and to maintain good operability. Moreover, a larger torsional rigidity can be obtained compared to the cross-sectional shape that is a perfect circle. As a result, it is effectively suppressed that a large twist occurs in this portion according to the rotational moment M transmitted from the head portion 1, and it is possible to prevent deterioration of the operation feeling caused by the head portion 1 wobbling. Such a portion having a substantially rectangular cross-sectional shape is preferably set over the entire range of the narrow portion up to the central position 2c of the neck portion 2 described above.

[0023] Also, a more preferable shape of the portion having a substantially rectangular cross-section in a cross-sectional view is formed into a vertically long substantially rectangular shape. Thereby, the left-right width can be made relatively small, so that the design property of the thin-type neck can be maintained, and the bending rigidity in the front-rear thickness direction can be made relatively large, preventing the neck portion 2 from bending greatly in the front-rear direction when brushing teeth, and good cleanability can be maintained.

[0024] In this example, as shown in FIGS. 5(a) and 5(b), the entire narrow region from the tip to the central position of the neck portion 2 is configured to have this vertically long substantially rectangular cross-sectional shape. Also, in this example, the narrow region has a straight shape in which each dimension of the vertically long substantially rectangular shape is the same (constant). The ratio (T2 / W2) of the front-rear thickness T2 to the left-right width W2 is preferably set to 1.01 to 1.50.

[0025] In the present embodiment, as shown in FIGS. 1 to 3, the handle portion 3 is provided with a bent portion 8 that is more bendable than adjacent portions (the base end portion of the neck portion 2 adjacent to the tip side and the portion of the handle portion 3 adjacent to the base end side) at the tip portion continuous with the neck portion 2. In this example, the bent portion 8 is composed of a rod-shaped movable portion 7 having a left-right width and a front-rear thickness connected to the base end of the neck portion 2 that are smaller than those of other portions of the handle portion 3, and a restricting portion 50 that is located around the movable portion 7 and restricts the bending operation of the movable portion 7 and supports the movable portion 7.

[0026] The handle portion 3 is, more specifically, as shown in FIG. 4, an axially-shaped core material 4 integrally formed with the head portion 1 and the neck portion 2 by the same rigid resin (first rigid resin) as that forming the head portion 1 and the neck portion 2, and a rigid resin having a property of low adhesion to the first rigid resin, that is, a property (low weldability) of being separated from each other after molding without mixing with the first rigid resin during molding. It has a coating material 5 that covers the core material 4 and is formed of a second rigid resin.

[0027] For example, a crystallized resin made of polyacetal resin (POM), polyamide resin (PA), polybutylene terephthalate (PBT), or polypropylene resin (PP), etc. has a property of low adhesion (low welding) to each other when the other is a crystallized resin (except for PP to PP) or a non-crystallized resin. Therefore, if either one of the first rigid resin constituting the core material 4 and the second rigid resin constituting the coating material 5 is a crystallized resin such as polyacetal resin (POM), and the other is a non-crystallized resin made of, for example, acrylonitrile-butadiene-styrene resin (ABS), polycarbonate (PC), or acrylic resin (PMMA), etc., the first rigid resin and the second rigid resin will not mix during molding, and the core material 4 and the coating material 5 will be in a separated state from each other after molding.

[0028] When both the first rigid resin and the second rigid resin are crystallized resins, it is possible to prevent the core material 4 and the coating material 5 from fusing with each other in principle. For example, if either one of the first rigid resin constituting the core material 4 and the second rigid resin constituting the coating material 5 is a crystallized resin such as polyacetal resin (POM), and the other is a crystallized resin made of polyacetal resin (POM), polyamide resin (PA), or polypropylene resin (PP), etc., it is possible to prevent the first rigid resin and the second rigid resin from mixing during molding and keep the core material 4 and the coating material 5 separated from each other after molding. However, among the above-mentioned crystallized resins, PP to PP has high adhesion, so the case where both the first rigid resin and the second rigid resin are polypropylene resin (PP) is excluded.

[0029] And as shown in FIG. 4, the core material 4 is composed of a substantially rod-shaped core material body 6 embedded in the coating material 5, and a movable part 7 provided on the tip side of the core material body 6, which bends and swings in the dorsal direction opposite to the protruding direction of the tuft 10 in response to the brushing pressure and constitutes the above-described bending part 8.

[0030] As shown in the enlarged view in FIG. 7, the movable part 7 is formed in a substantially oblong shape with a vertical length such that the thickness in the front-rear direction from the back to the belly is larger than the left-right width in the lateral direction in cross-section. Further, the outer peripheral surface is composed of a pair of flat inclined surfaces 71, 71 that are inclined inward from the position of the widest hem, in this example, the central position 70 in the front-rear direction, to the belly side and the dorsal side, respectively, and extend linearly by a predetermined length L to the belly side or the dorsal side, and a convex curved surface 72 that is substantially arc-shaped in cross-section connecting the extended ends thereof, forming a cross-sectional view that is substantially arch-shaped. The inclination angle θ of each inclined surface 71 of the pair of inclined surfaces 71 on the belly side and the dorsal side is 3 degrees or more, and the length of each inclined surface 71 is preferably 1 mm or more and 2 mm or less.

[0031] On the other hand, as can be seen from FIGS. 6, 8, and 9, the tip-side portion of the coating material 5 has a pair of arm portions 51, 51 that branch to the left and right, and a through groove 52 is formed between the arm portions 51, 51 to allow the coating material 5 to penetrate from the dorsal side to the ventral side and permit the swinging displacement of the movable part 7. Further, a connecting part 53 that holds the ventral part of the movable part 7 is provided between the ventral tip portions of the arm portions 51, 51. These arm portions 51, 51 and the connecting part 53 constitute the restricting part 50 that restricts and supports the bending operation of the movable part 7.

[0032] As shown in FIG. 6(a), the connecting part 53 has a recessed hole 59 having inclined surfaces 57, 57 and a concave curved surface 58 corresponding to the inclined surfaces 71, 71 and the convex curved surface 72 of the movable part 7. And by fitting and holding the ventral part of the movable part 7 in the recessed hole 59 of the connecting part 53, the swinging displacement of the movable part 7 to the ventral side, the lateral deviation in which the movable part 7 is displaced in the left-right lateral direction, and the torsion in which the movable part 7 rotates about the axis center are respectively restricted.

[0033] When the movable part 7 swings and displaces, the movable part 7 can be smoothly swung and displaced without rubbing against the recessed hole 59 of the connecting part 53. Moreover, since a convex curved surface 72 that is substantially arc-shaped in cross-section and connects the extending ends of the inclined surfaces 71, 71 is provided on the movable part 7, when the bent state of the movable part 7d is released and it returns to its original shape, the peripheral surface of the movable part 7 will not get caught in the recessed hole 59 of the connecting part 53, and the ventral part of the movable part 7 can be neatly accommodated in the recessed hole 59.

[0034] In this example, the cross-sectional shape of the movable part 7 is uniform in the length direction, but this is not necessary. For example, it is also possible to gradually change the cross-sectional shape of the movable part 7. However, when the movable part 7 has a uniform cross-sectional shape in the length direction, etc., including the holding part by the connecting part 53 and the area exposed in the through groove 52, on the ventral side of the movable part 7, a cross-sectionally substantially arch-shaped surface composed of a pair of flat inclined surfaces 71, 71 and a convex curved surface 72 that is substantially arc-shaped in cross-section and connects the extending ends thereof is provided, there is an advantage that the toothbrush formed in the molding space of the molding die can be easily taken out.

[0035] The toothbrush H of this example is provided with a special structure as the bent part 8 as described above, but the present invention is not limited to this. As shown in FIGS. 10 and 11, it also includes a toothbrush with a simple structure without a bent part 8. In FIGS. 10 and 11, the same components as those of the toothbrush H in the above representative embodiment (FIGS. 1 to 3) are denoted by the same reference numerals, and the description thereof is omitted.

[0036] (deflection amounts d1 to d3) The deflection amount of the toothbrush of the present invention is first, as shown in FIG. 12(a), with the protruding direction of the tuft 10 facing upward and the tuft-planting surface 12 on which the tuft 10 of the head part 1 is planted being horizontal, fix a position p2 that is 110 mm horizontally away from the axial center position p1 of the tuft-planting surface 12 toward the proximal end side, and set the position of the tip of the head part 1 in the no-load state as L0. The "tip" of the head part refers to the position that is the most distal in the axial direction of the head part. When there are left-right widths and front-back thicknesses, they are respectively the central positions.

[0037] Then, as shown in Fig. 12(b), a 150 g weight is suspended at the axial center position p1 of the implanting surface 12 of the head portion 1 in the no-load state, and the vertical distance between the position L1 of the tip of the head portion 1 after 10 seconds and the above L0 is the deflection amount d1 (mm). Similarly, as shown in Fig. 13(a), a 200 g weight is suspended at the axial center position p1 of the implanting surface 12 of the head portion 1 in the no-load state, and the vertical distance between the position L2 of the tip of the head portion 1 after 10 seconds and the above L0 is the deflection amount d2 (mm). As shown in Fig. 13(b), a 250 g weight is suspended at the axial center position p1 of the implanting surface 12 of the head portion 1 in the no-load state, and the vertical distance between the position L3 of the tip of the head portion 1 after 10 seconds and the above L0 is the deflection amount d3 (mm).

[0038] (Differences C1 and C2 in deflection amount) The difference C1 in deflection amount is the difference (d2 - d1) (mm) between d2 and d1. The difference C2 in deflection amount is the difference (d3 - d2) (mm) between d3 and d2. The toothbrush of the present invention is a toothbrush in which the relationship between these differences C1 and C2 in deflection amount satisfies C1 < C2, whereby overbrushing can be avoided, and at the same time, the operability and gripability of the toothbrush do not deteriorate, and excellent cleaning performance and operability can be maintained.

[0039] The difference C1 in deflection amount is preferably 6 mm or less. Usually, the force applied to the head portion during cleaning is about 150 to 200 gf. When a force is applied from 150 gf, which is a relatively small force, to 200 gf, if the toothbrush deflects more than 6 mm, the posture of the head is likely to become unstable, the operability deteriorates, and the cleaning feeling may deteriorate. Also, C1 is preferably 1.0 mm or more. If it is less than 1.0 mm, the deflection is small and overbrushing is likely to occur.

[0040] The sum (C1 + C2) of the deflections C1 and C2 is preferably 8 mm or less. C1 + C2 is the variation range of the force applied to the head part including the overbrushing state of 200 to 250 gf, that is, the deflection variation range within the range of 150 to 250 gf. However, if the value of C1 + C2 becomes larger than 8 mm, in addition to the deterioration of the cleaning feeling, there is also a possibility of breakage due to deflection depending on the constituent material, which is not preferable. Also, C1 + c2 is preferably 2.0 mm or more, more preferably 4.0 mm or more. If it is less than 4.0 mm, especially less than 2.0 mm, the deflection is small and overbrushing is likely to occur.

[0041] The difference (C2 - C1) between the deflections C1 and C2 of the amount of deflection is preferably 0.5 mm or more. If C2 - C1 is less than 0.5 mm, the overbrushing relaxation effect of the toothbrush when the force applied to the head part exceeds 200 gf and overbrushing occurs (the effect of releasing the force because it becomes easier to deflect when it is 200 gf or more) cannot be felt, and there is a possibility that it may not be noticed that too much force is applied during cleaning.

[0042] Hereinafter, examples and comparative examples of the toothbrush will be described.

[0043] Examples 1 and 4 are samples manufactured as toothbrushes having a bent portion as shown in FIGS. 1 and 2, and Examples 2 and 3 and Comparative Examples 1 to 4 are samples manufactured as toothbrushes having no bent portion as shown in FIGS. 12 and 13. The cross-sectional shape of the neck portion is the same as that of Examples 1 and 4 such as FIG. 1 above.

[0044] For each example, the overall length L1, head width W1, head thickness T1 of the toothbrush, the distance L2 along the axial direction from the head tip to the widest position of the finger rest part of the handle, the left - right width W2 of the narrowest part in the left - right lateral width of the neck part (neck thinnest part), the front - back thickness T2 of the same neck thinnest part, in Examples 1 and 4, the left - right width W3 of the movable part 7 constituting the bending part, also the front - back thickness T3 of the movable part 7, the materials of the head part, neck part and handle part (core part in Examples 1 and 4) of each example, the materials of the coating parts in Examples 1 and 4, and the materials of the filaments constituting the tufts are as shown in Table 1. Other dimensions, the arrangement of the tufts, the number, the arrangement of the filaments, the number, etc. were all set to be the same.

[0045]

Table 1

[0046] For the differences C1, C2, C2 - C1, C1 + C2 in the amount of deflection of each example, the amounts of deflection d1, d2, d3 measured by the above - mentioned method were measured, and C1 = d2 - d1 (mm), C2 = d3 - d2 (mm) were obtained by calculation. Also, for Examples 1 and 2 and Comparative Examples 2 to 4, an in - mouth use evaluation (operability, cleaning property of the back teeth, cleaning property between teeth, harmfulness (gentleness of hitting the gingiva)) was conducted by 3 panelists. The evaluation was carried out in three levels: "〇": good, "△": neither good nor bad, "×": bad. The results are shown in Table 2 and the graph in Fig. 16.

[0047]

Table 2

[0048] As can be seen from the results in Table 2, the toothbrushes of Examples 1 and 2 satisfy C1 < C2 (C2 - C1 is a positive value), avoid over - brushing, have good harmfulness (gentleness of hitting the gingiva), and at the same time, especially in Example 1, have excellent cleaning properties (both for back teeth and between teeth) and excellent operability. In contrast, among Comparative Examples 2 to 4 with C1≧C2, in Comparative Examples 2 and 3, both the harmfulness and the operability are neither good nor bad, and in Comparative Example 4, although the harmfulness is good, both the operability and the cleaning property are bad.

Description of Symbols

[0049] 1 Head part 2 Neck part 3 Handle part 4 Core material 5 Coating material 6 Core material body 7 Movable part 8 Bending part 10 Bristle bundle 50 Regulation part 51 Arm part 52 Through groove 53 Connecting part 57 Inclined surface 58 Concave curved surface 59 Recessed hole 71 Inclined surface 72 Convex curved surface H Toothbrush

Claims

1. A toothbrush comprising a head portion in which tufts of bristles are implanted, a neck portion connected to the proximal end side of the head portion, and a handle portion serving as a grip connected to the proximal end side of the neck portion, wherein the relationship between the deflection amount differences C1 and C2 is C1 < C2. With the protruding direction of the tufts of bristles facing upward and the posture in which the bristle-implanted surface of the head portion is horizontal, a position 110 mm horizontally away from the axial center position of the bristle-implanted surface toward the proximal end side is fixed. The vertical distance between the position of the tip of the head portion in the no-load state and the position of the tip of the head portion 10 seconds after suspending a 150 g weight at the axial center position of the bristle-implanted surface is defined as the deflection amount d1 (mm). The vertical distance between the position of the tip of the head portion in the no-load state and the position of the tip of the head portion 10 seconds after suspending a 200 g weight at the axial center position of the bristle-implanted surface is defined as the deflection amount d2 (mm). The vertical distance between the position of the tip of the head portion in the no-load state and the position of the tip of the head portion 10 seconds after suspending a 250 g weight at the axial center position of the bristle-implanted surface is defined as the deflection amount d3 (mm). The difference between d2 and d1 is defined as the deflection amount difference C1 (mm), and the difference between d3 and d2 is defined as the deflection amount difference C2 (mm).

2. The toothbrush according to claim 1, wherein the deflection amount difference C1 is 6 mm or less.

3. The toothbrush according to claim 1, wherein the sum of the deflection amount differences C1 and C2 is 8 mm or less.

4. The toothbrush according to claim 1, wherein the difference between the deflection amount differences C1 and C2 is 0.5 mm or more.

5. The toothbrush according to claim 1, wherein a bent portion that is more likely to bend than adjacent portions is provided at the neck portion, the handle portion, or the boundary portion between them.

6. The toothbrush according to claim 1, wherein at least a part of the head portion, the neck portion, and the handle portion are integrally formed of the same resin.

7. The toothbrush according to claim 1, wherein the width of the narrowest part of the neck portion is 5 mm or less and the thickness is 5 mm or less.

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