TWI807151B - toothbrush - Google Patents

Abstract

The toothbrush (1) of the present invention comprises a toothbrush body (10) and a puncture-resistant throat plate (20) arranged on the toothbrush body (10). The toothbrush body (10) is composed of a body portion (11) comprising a hard resin material and a first covering portion comprising a soft resin material. The body portion (11) comprises: a brush head (13) with a flocking surface (19); a neck (14) extending from the rear end of the brush head (13); a handle portion (16) ), located on the opposite side of the neck to the brush head (13); and a plate fitting base part, disposed between the neck (14) and the handle (16); the first covering part covers at least a part of the surface of the neck (14).

Description

toothbrush

The present invention relates to a toothbrush.

This application claims priority based on Japanese Patent Application No. 2018-246854 filed in Japan on December 28, 2018, and the contents thereof are incorporated herein by reference.

Habituation of plaque control from early childhood can greatly affect oral health throughout life, so proper brushing technique must be learned. However, infants and young children are not used to brushing their teeth, so they must be wary of swallowing the toothbrush by mistake or causing throat irritation caused by inversion. In addition, there is a concern that biting the toothbrush during tooth brushing may cause unevenness or burrs on the surface of the toothbrush, thereby causing damage to the oral cavity.

As a countermeasure against throat stabbing caused by toothbrushes, a "throat stab-resistant toothbrush" has been sold in which a large ring-shaped stab-resistant throat plate is fitted to the base of the neck of the toothbrush so that the toothbrush cannot be swallowed (for example, Patent Document 1).

On the other hand, as a measure to prevent the toothbrush from being bitten, there is a method of covering the brush head with a hard resin material such as polypropylene (primary side resin) with a soft resin material (secondary side resin) such as an elastomer to the neck, so as not to cause damage to the surface. This countermeasure is also widely adopted because of the advantage that even if the primary side resin breaks, the sharp fractured surface is hardly exposed because the surface is covered with the secondary side resin (for example, Patent Document 2).

[Prior art literature] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 57-162732

[Patent Document 2] Japanese Patent No. 5830277

However, when the above-mentioned measure of covering the primary resin with the secondary resin is applied to the neck of the toothbrush, it becomes a so-called double-core structure, so it is difficult to obtain the volume of the primary resin, and a problem arises in terms of strength. In particular, in toothbrushes for infants with small oral cavity, the size of the brush head and the diameter of the neck of the toothbrush are limited, so measures other than increasing the amount of resin on the primary side are required.

In addition, if the above-mentioned double-core structure is applied to a "throat-resistant toothbrush", the technical difficulty in terms of strength will be further increased. In the "stab-resistant toothbrush", the puncture-resistant throat plate is also fitted to the base of the neck, so it is necessary to form a base using primary side resin at the mounting site. However, when the toothbrush is used, stress concentration is likely to occur at the connecting portion between the base and the neck. Considering that toothbrushes for infants tend to have a shorter neck length, the stress concentration at the time of tooth brushing will further increase.

In this way, there is a big problem in terms of strength in toothbrushes for infants and young children that have a "stab-resistant throat plate" as a countermeasure against stabbing throat and "coating with an elastic body" as a countermeasure against biting.

One aspect of the present invention is made in view of the above-mentioned problems of the prior art, and its object is to provide an Toothbrush with high strength of stress concentration at the time of raw brushing.

A toothbrush according to one aspect of the present invention is characterized by comprising a toothbrush body and a puncture-resistant throat plate provided on the toothbrush body. The toothbrush body is composed of a body portion made of a hard resin material and a first covering portion made of a soft resin material. The body portion includes: a brush head having a flocking surface; a neck extending from the rear end of the brush head; a handle portion located on the opposite side of the neck from the brush head; part of the surface.

In the toothbrush according to one aspect of the present invention, a cutout portion may be provided in a part of the plate fitting base portion in the circumferential direction, and the first covering portion and the second covering portion covering at least a part of the handle portion may be continuous and integrated through the cutout portion.

In the toothbrush according to one aspect of the present invention, the plate fitting base portion may have a fitting portion fitted to the plate-side fitting receiving portion of the puncture-resistant throat plate; and an insertion portion inserted into a through hole of the plate-side fitting receiving portion; and the notch portion penetrates the fitting portion and the insertion portion.

In the toothbrush according to one aspect of the present invention, an exposed portion adjacent to the plate fitting base portion and not covered by the first covering portion may exist at an end portion of the neck portion on the side of the handle portion.

In the toothbrush according to one aspect of the present invention, the exposed portion may have at least one stress relief portion on the boundary side with the first covering portion. part, the boundary between the stress relieving part and the first covering part forms a U-shape that is concave toward the handle part side.

In the toothbrush according to one aspect of the present invention, the first covering part may cover the entire circumferential direction of the neck in an area of at least 60% or more when the total length of the neck in the longitudinal direction is taken as 100%.

In the toothbrush according to one aspect of the present invention, the U-shaped depth of the stress relaxation portion may be in a range of 0.8 mm to 1.6 mm.

In the toothbrush according to one aspect of the present invention, the exposed portion may have at least one stress relieving portion on the boundary side with the first covering portion, the boundary between the stress relieving portion and the first covering portion forms a Y-shape concave toward the handle portion, and the first covering portion and the second covering portion covering at least a part of the handle portion are continuous and integrated with each other through the cutout.

According to one aspect of the present invention, the neck may have a cross-sectional shape of a circle or an ellipse, the width of which is fixed or enlarged in the longitudinal direction, and when the entire length of the neck in the longitudinal direction is taken as 100%, the first covering part covers the entire circumferential direction of the neck in at least 40% or more of the region.

In the toothbrush according to one aspect of the present invention, the Y-shaped depth of the stress relaxation portion may be in a range of not less than 1.0 mm and not more than 3.5 mm.

In the toothbrush according to one aspect of the present invention, the stress relieving portion may be provided in the circumferential direction of the neck portion so as to be opposite to the hair-implanted surface. same side.

In the toothbrush according to one aspect of the present invention, the starting point on the neck side of the stress relaxation portion may be formed in the same width as the neck portion.

According to one aspect of the present invention, a configuration may be adopted in which the minimum value of the width and thickness of the neck is 4.0 mm or more and 7.0 mm or less.

According to one aspect of the present invention, a configuration may be adopted in which the surface of the brush head portion is covered with the first covering portion.

According to the present invention, it is possible to provide a high-strength toothbrush that prevents throat sting or bites during use, and that is less prone to stress concentration during tooth brushing.

1, 40: Toothbrush

10, 40A: Toothbrush body

11, 41: Main body

11a, 11b, 41a, 41b: ends

11c, 11d: corner

11A: Surface (first surface)

11B: second surface

11F: step difference department

12, 42: coating part

12A, 15b, 20a, 45b: surface

13, 43: brush head

13a: Hair planting department

13A: Brush head body

14, 44: Neck

14A: Neck Body

15, 45: Plate fitting base part

15a, 45a: foundation

15A, 45A: Plate fitting part

15B, 45B: insertion part

16, 46: handle part

16a: front

16b: side

16c, 20b: back

16A: Handle body

17, 47: the second cladding part

18, 48: the first cladding part

19, 49A, 49B: Flocking surface

19a: Hair planting hole

19b: hair bundle

20: Anti-stab throat plate

21: Through hole

22: Design

23: Plate side fitting receiving part

31: Incision

32: finger contact part

33: exposed part

34, 54: Stress relieving part

40B: The second anti-stab throat plate

43a: Mao

45C: Enhancement Department

47a: opening

53: exposed part

d1, d2: diameter

D1: outer diameter

D2: inner diameter

J: Borderline

L1, L2, L3, L4, L5: Length

L6: Distance

M: place (meeting point)

N: Boundary location

O: central axis

O1, O2: center

P1: Boundary

R, R1, R2: radius

T:U word depth

T2:Y word depth

W, W2, W3: Width

Fig. 1 is a perspective view showing the overall configuration of a toothbrush according to a first embodiment.

Fig. 2 is a front view showing the structure of the toothbrush body of the first embodiment.

Fig. 3 is a side view showing the structure of the toothbrush body of the first embodiment.

Fig. 4 is a rear view showing the structure of the toothbrush body of the first embodiment.

FIG. 5 is an enlarged view showing a part of the neck portion of the first embodiment.

Fig. 6 is a front view showing the structure of the stab-resistant throat plate of the first embodiment.

Fig. 7 is a perspective view showing the structure of the stab-resistant throat panel of the first embodiment from the back side.

8 is a cross-sectional view showing a boundary portion between a main body portion and a covering portion in the first embodiment; face map.

Fig. 9A is a front view showing the structure of a toothbrush according to a second embodiment.

Fig. 9B is a rear view showing the structure of the toothbrush according to the second embodiment.

Fig. 10A is a front view showing the structure of a toothbrush body according to a second embodiment.

Fig. 10B is a rear view showing the structure of the toothbrush body of the second embodiment.

Fig. 11 is a partially enlarged view showing the configuration around the neck of the toothbrush body according to the second embodiment.

Fig. 12 is a partially enlarged view showing the configuration around the neck of the toothbrush body according to the second embodiment.

Hereinafter, the structure of the toothbrush which concerns on each embodiment of this invention is demonstrated.

In addition, in each of the following drawings, in order to make each constituent element easy to see, it may show that the scale of a dimension differs depending on a constituent element.

[first embodiment]

FIG. 1 is a perspective view showing the overall configuration of a toothbrush 1 according to the first embodiment. Fig. 2 is a front view showing the structure of the toothbrush body 10 according to the first embodiment. Fig. 3 is a side view showing the structure of the toothbrush body of the first embodiment. Fig. 4 is a rear view showing the structure of the toothbrush body 10 according to the first embodiment. FIG. 5 is an enlarged view showing a part of the neck portion 14 of the first embodiment.

The toothbrush 1 of the present embodiment shown in FIG. 1 is configured as a toothbrush assumed to be used by children from six months to about two years old. The toothbrush 1 includes a toothbrush body 10 and a puncture-resistant throat plate 20 detachably attached to the toothbrush body 10 .

The toothbrush body 10 has an elongated shape as a whole, and has a body portion 11 made of a hard resin material, and a coating portion 12 made of a soft resin material covering at least a part of the surface of the body portion 11 .

The main body portion 11 includes a head body 13A, a neck body 14A, a plate fitting base portion 15 ( FIG. 2 ), and a handle body 16A, which are integrally formed in this order.

The main body 11 can be produced by injection molding using a hard resin material, for example.

As the constituent material of the main body portion 11, for example, polypropylene (Polypropylene, PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polycyclohexylene dimethylene terephthalate (PCT), ), polyacetal (Polyoxymethylene (POM)), polyethylene naphthalate (Polyethylene Naphthalate, PEN), polystyrene (Polystyrene, PS), acrylonitrile‧butadiene‧styrene resin (Acrylonitrile Butadiene Styrene, ABS), cellulose propionate (Cellulose Propionate, CP), polyarylate, polycarbonate, acrylonitrile‧benzene Ethylene copolymer resin (Acrylonitrile Styrene, AS), etc. Among these resin materials, materials such as POM, PBT, and PEN are preferably used from the viewpoint of high strength and ease of thinning the brush head portion 13 . In addition, one kind of resin may be used individually as said resin, and 2 or more types of resin may be used together.

As shown in FIG. 8 , the body part 11 has: not covered by the covering part 12 but exposed The first surface 11A protruding to the outside, the second surface 11B covered by the covering part 12 , and the step part 11F formed at the boundary part between the main body part 11 and the covering part 12 .

As shown in FIG. 2 , the covering portion 12 includes a first covering portion 18 covering at least a part of the surface of the neck body 14A, and a second covering portion 17 covering at least a part or the entire surface of the handle body 16A.

As the soft resin material of the covering part 12 , for example, a resin having a Shore A of 90 or less is preferable, and a resin having a Shore A of 30-80 is more preferable. Examples of such a soft resin material include elastomer resins such as polyolefin-based elastomers, styrene-based elastomers, polyester-based elastomers, polyurethane-based thermoplastic elastomers, silicon, and the like. In the case of using a soft resin such as an elastomer, for example, polyolefin is preferable from the viewpoint that adhesiveness can be improved, and polypropylene is more preferable as a hard resin material in this case.

(anti-stab throat plate)

First, the configuration of the stab-resistant throat plate 20 will be described in detail.

FIG. 6 is a front view showing the structure of the stab-resistant throat panel 20 of the first embodiment. FIG. 7 is a perspective view showing the configuration of the stab-resistant throat panel 20 of the first embodiment viewed from the back surface 20b side. 8 is a cross-sectional view showing a boundary portion between a main body portion and a covering portion in the first embodiment.

As shown in FIG. 6 , the stab-resistant throat plate 20 is formed in a disk shape as a whole, and an arbitrary design 22 is given on the surface 20 a side. The anti-stab throat panel 20 has a shape that curves from the center to the edge, the surface 20a side shown in FIG. 6 becomes convex, and the back surface 20b side shown in FIG. 7 becomes concave. From the point of view of preventing throat piercing and operability, The outer diameter of the anti-stab throat plate 20 is preferably about 45 mm to 55 mm. The material of the puncture-resistant throat plate 20 may also include the above-mentioned hard material, but if it includes the above-mentioned soft resin material, it is more preferable from the viewpoint of preventing throat-piercing or biting during use.

In the center of the stab-resistant throat plate 20, a through hole 21 concentric with the central axis O is formed. The diameter d1 of the through hole 21 is preferably about 12 mm to 15 mm.

On the rear surface 20b side of the stab-proof throat panel 20, a panel-side fitting receiving portion 23 concentric with the central axis O is provided. The plate-side fitting receiving portion 23 is formed in a cylindrical shape. The diameter d2 of the plate-side fitting receiving portion 23 is preferably about 16 mm to 20 mm. In addition, it is more preferable that the diameter d2 of the plate-side fitting receiving portion 23 is larger than the diameter d1 of the through hole 21 (d1<d2), and d1/d2 (ratio) is about 0.65 to 0.80.

If it is in the above range, the contact area between the anti-stab throat plate 20 and the plate fitting portion 15A and the insertion portion 15B on the side of the toothbrush body 10 shown in FIG. In particular, when the stab-resistant throat plate 20 is made of a soft resin material, the above-mentioned effects are further exhibited.

(toothbrush body)

Next, the configuration of the toothbrush main body 10 will be described in detail.

In the present embodiment, the toothbrush 1 is intended for use by infants, so the overall length of the toothbrush body 10 in the longitudinal direction is determined in consideration of the operability of infants, and is preferably about 100 mm to 140 mm, for example.

As shown in FIGS. 2 to 4 , the brush head 13 is located at the front end side of the main body 11 , and has a flocking surface 19 on one side in the thickness direction. The brush head 13 is provided with a plurality of hair-planting parts 13a (FIG. 1), the hair bundle 19b which bundled the several bristle of predetermined length to each of the some circular hair-planting hole 19a formed in the hair-planting surface 19 is planted.

The material of the bristles constituting the hair bundle 19b is not particularly limited. For example, polyamides such as 6-12 nylon and 6-10 nylon, polyesters such as PET, PBT, polytrimethylene terephthalate (PTT), PEN, polyesters such as polybutylene naphthalate (Polybutylene Naphthalate, PBN), polyolefins such as PP, olefin-based elastomers, and styrene-based elastomers can be used. Synthetic resin materials such as elastomers. These resin materials may be used alone or in combination of two or more.

The neck portion 14 is a portion extended from one end side of the brush head portion 13 .

Specifically, as shown in FIG. 2 , it is the length L1 from the end point of the curve forming the chamfer from the neck 14 in the plan view shape of the brush head 13, that is, the position of the boundary P1 where the bending direction of the curve forming the chamfer changes, to the surface 15b of the insertion portion 15B. The cross-sectional shape of the neck 14 is circular or elliptical, and its width is fixed or expanded along the length direction.

The length of the neck 14 is determined in consideration of the size of the oral cavity of infants. In this embodiment, for example, the length L1 of the neck portion 14 is preferably about 14 mm to 21 mm, more preferably about 16 mm to 18 mm.

In addition, the width and thickness (minimum diameter) of the thinnest part of the neck 14 are preferably about 4.0 mm to 7.0 mm, more preferably in the range of 5.0 mm to 7.0 mm. In addition, the width and thickness (maximum diameter) of the thickest part of the neck portion 14 are preferably about 5.0 mm to 9.0 mm, more preferably in the range of 5.0 mm to 8.0 mm. Furthermore, the dimensions of the width and thickness of the neck 14 include the first coating The dimension of the thickness of the portion 18.

The handle portion 16 is a portion extended from one end side of the neck portion 14 (the end portion on the side opposite to the end portion on the brush head portion 13 side), and is a portion held by a user. In the present embodiment, the handle portion 16 is defined from the end portion 11b of the main body portion 11 on the side opposite to the end portion 11a on the brush head portion 13 side to the base 15a of the plate fitting base portion 15 . The width of the handle portion 16 is formed wider than the width of the neck portion 14 . In addition, the length of the handle portion 16 is set according to the size of the hand of an infant, and is preferably about 65 mm to 80 mm, for example.

The plate fitting base portion 15 is disposed between the neck portion 14 and the handle portion 16. For example, in consideration of preventing infants from stabbing their throats, the length L2 along the long axis direction (the distance from the surface 15b of the insertion portion 15B to the base 15a of the plate fitting portion 15A) is preferably in the range of 4 mm to 8 mm.

Furthermore, the surface 15 b of the insertion portion 15B is more preferably provided at a position 30 mm to 55 mm away from the front end of the brush head 13 . The plate fitting base portion 15 is formed in an annular shape around the axis of the toothbrush body 10 . The plate fitting base portion 15 has a plate fitting portion 15A and an insertion portion 15B having mutually different diameters, and is formed so as to expand concentrically outward in the minor axis direction compared with the neck portion 14 and the handle portion 16 .

The insertion portion 15B is a portion located on the neck 14 side of the panel fitting base portion 15 and inserted into the through hole 21 of the stab-resistant throat panel 20 shown in FIGS. 6 and 7 . The diameter of the insertion portion 15B is preferably approximately the same as the diameter of the through hole 21 . Also in order to ensure waterproofness, it is desirable that the mutual gap is small in the state where the insertion portion 15B is inserted into the through hole 21 .

In addition, when the insertion portion 15B is inserted into the through hole 21 , preferably, as shown in FIG. By eliminating the level difference between the surface 20a of the anti-stab throat plate 20 and the surface 15b of the insertion portion 15B, it is difficult for moisture to accumulate and it can be used hygienically.

As shown in FIG. 2 , the board fitting portion 15A is located on the side of the handle portion 16 in the board fitting base portion 15 . The plate fitting portion 15A is a portion having a larger diameter than the insertion portion 15B, and is fitted to the plate-side fitting receiving portion 23 of the stab-resistant throat plate 20 shown in FIG. 7 .

In the plate fitting base portion 15, the diameter of the insertion portion 15B corresponds to the diameter d1 of the through hole 21 of the stab-resistant throat plate 20 shown in FIG. 7, and is set within a range of 12 mm to 15 mm. In addition, the thickness of the insertion portion 15B in the long-axis direction is set so as to fall within the range of 1.0 mm to 3.0 mm.

The diameter of the plate fitting portion 15A corresponds to the diameter d2 of the plate-side fitting receiving portion 23 of the stab-resistant throat plate 20 , and is set within a range of 16 mm to 20 mm. In addition, the thickness of the plate fitting part 15A in the long-axis direction is set so as to fall within the range of 4.0 mm to 6.0 mm.

As shown in FIG. 4 , a notch 31 penetrating the insertion portion 15B and the plate fitting portion 15A in the axial direction is provided in a part of the circumferential direction of the plate fitting base portion 15 . The notch part 31 is a part cut toward the center of the board fitting base part 15, and is provided in the back surface (surface opposite to the flocking surface 19) side of the toothbrush main body 10. As shown in FIG. The cutting depth of the notch portion 31 is preferably a depth at which the convex shape of the plate fitting base portion 15 disappears. In this embodiment, the bottom surface of the notch 31 becomes the same surface as the surfaces of the handle 16 and the neck 14 so as to smoothly connect the surface of the handle 16 and the surface of the neck 14. catch.

The width of the cutout portion 31 is preferably within a range of 1.5 mm to 6.0 mm, more preferably 2.0 mm to 5.0 mm. By setting it in the said range, the contact area of the stab-resistant throat plate 20 and the plate fitting base part 15 can be ensured, and the stab-resistant throat plate 20 can be more stably fixed to a toothbrush main body. In addition, concentration of stress described later can be alleviated. In addition, the depth of the notch part 31 is equivalent to the flange width of 15 A of plate fitting parts, and is made into the range of 3.0 mm - 7.0 mm.

As shown in FIGS. 2 , 3 and 4 , the second covering portion 17 is provided in such a manner that, except for the surface on the rear end side of the handle portion 16, it covers the side surfaces 16b and 16b on both sides from the back surface 16c of the handle portion 16, and further covers a part of the front surface 16a (the side surface 16b and the edges of the side surface 16b), and continuously covers these parts. In this way, at least a part or the entire surface of the handle portion 16 is covered by the second covering portion 17 , thereby improving the hand comfort of the user when holding the handle portion 16 and preventing slipping of the gripping fingers.

The first covering part 18 is provided in the following manner: in the circumferential direction, it covers at least a part of the surface of the entire surface of the brush head 13 except for the flocking surface 19 and at least a part of the surface of the neck 14 except for a part of the area on the base end side. In this embodiment, for example, when the entire length of the neck 14 in the longitudinal direction is taken as 100%, the entire circumference of the neck 14 is covered by the first covering portion 18 in at least 60% or more of the region. The biting of the brush head 13 and the neck 14 can be prevented by the first covering part 18, and it is more preferable if the covering range is more than 80%.

In this embodiment, for example, about 60% or more of the total surface area of the neck portion 14 is covered by the first covering portion 18 . The biting of the brush head 13 and the neck 14 can be prevented by the first covering part 18 . In addition, it is more preferable that the covering range of the first covering part 18 is 60% or more and 90% or less.

The second covering part 17 and the first covering part 18 are continuous through the notch part 31 provided in the board fitting base part 15, and are integrally formed to constitute the covering part 12. The thickness of the covering part 12 is set to the minimum thickness which feels soft when bitten and hardly causes damage. The thickness of the covering portion 12 is preferably not less than 0.7 mm and not more than 1.1 mm, more preferably not less than 0.8 mm and not more than 0.9 mm. By setting the thickness of the coating part 12 to 0.7 mm or more, the effect by coating can be acquired. In addition, by increasing the amount of resin to be filled in the manufacturing stage, short shots are less likely to occur, and a part of the molded product will not be chipped. Moreover, by making the thickness of the covering part 12 into 1.1 mm or less, the intensity|strength of the neck part 14 can be fully ensured especially. Therefore, the thickness of the covering portion 12 is preferably set within the above range.

In addition, as shown in FIG. 8 , it is preferable that at least the surface 11A and the surface 12A of the boundary portion between the cover portion 12 and the main body portion 11 have a small level difference. Therefore, the height of the step portion 11F of the main body portion 11 is set corresponding to the thickness of the covering portion 12 , whereby the first surface 11A and the surface 12A of the covering portion 12 can be flushed.

In addition, the corner portion 11 c on the first surface 11A side of the step portion 11F is preferably a rounded corner with a radius of 0.2 mm to 0.5 mm that places the center O1 inside the main body portion 11 . The corner portion 11 d on the second surface 11B side of the step portion 11F is preferably a rounded corner with a radius of 0.2 mm to 0.5 mm with the center O2 placed outside the main body portion 11 .

In this way, if the radius of each corner 11c and corner 11d of the boundary portion is 0.2 mm or more, even in the portion where the volume of the hard resin changes greatly, the stress is easily dispersed and the strength is improved.

Moreover, when the radius of each corner part 11c and corner part 11d is 0.5 mm or less, generation|occurrence|production of burrs at the time of molding can be suppressed.

In addition, as shown in FIGS. 2 and 3 , a finger contact portion 32 made of soft resin may be provided on a part of the front surface of the handle portion 16 . The finger contact portion 32 is located near the neck portion 14 of the handle portion 16. In order to connect (penetrate) the second covering portion 17 on the back side with the toothbrush body 10, this portion does not need to be within the range of the thickness of the soft resin as described above. Arbitrary designs, characters, etc. may be given to the finger contact portion 32 . Furthermore, the finger contact portion 32 may have a certain thickness in order to make the design or characters stand out.

In this embodiment, as shown in FIG. 5 , an exposed portion 33 adjacent to the plate fitting base portion 15 and not covered by the first covering portion 18 exists at the end portion of the neck portion 14 on the side of the handle portion 16 . Of the surface of the neck 14 , the entire area except the exposed portion 33 is covered with the first covering portion 18 . The exposed portion 33 has at least one stress relieving portion 34 on the boundary side with the first covering portion 18 . As can also be seen from the front view shown in FIG. 5 , the stress relieving portion 34 is provided on the same front side as the flocking surface 19 in the circumferential direction of the neck 14 , and is formed with the same width as the neck 14 .

The boundary between the stress relieving portion 34 and the first covering portion 18 has a gentle U-shape that is recessed toward the handle portion 16 and opened toward the brush head 13 side. The U-shaped depth T of the stress relieving portion 34 is preferably in the range of 0.8 mm to 1.6 mm, and more preferably Preferably, it is within the range of not less than 1.0 mm and not more than 1.4 mm. By setting the U-shaped depth T within the range of 0.8 mm to 1.6 mm, concentrated stress can be relaxed and sufficient strength can be ensured for the boundary portion between the neck portion 14 and the plate fitting base portion 15 where the bending behavior of the first covering portion 18 made of a soft resin material changes rapidly.

The radius R of the U-shape of the stress relaxation portion 34 is preferably about 3.0 mm to 6.0 mm, more preferably about 4.0 mm to 5.0 mm. If the U-shape of the stress relieving portion 34 is too sharp, the effect of dispersing the stress will be weakened, so it is preferable to set it within the above-mentioned range.

In the present embodiment, the stress relieving portion 34 is formed only on the front side of the neck portion 14, for example. Thereby, it is possible to relax the stress on the boundary between the neck portion 14 and the front side of the plate fitting base portion 15 , which tends to warp due to stress concentration during use.

In this embodiment, the exposed portion 33 has one stress relieving portion 34 , but for example, the stress relieving portion 34 may be provided on both sides of the neck 14 to have two or more stress relieving portions 34 .

As shown in FIG. 5 , except for the notch 31 ( FIG. 4 ), among the boundaries between the first covering portion 18 and the exposed portion 33, the position of the boundary line J closest to the handle portion 16 is preferably located on the brush head 13 side compared with the starting position of the plate fitting base portion 15. The starting position of the board fitting base part 15 of this embodiment is the position of the surface 15b of the insertion part 15B when seeing from the front side of the toothbrush 1. As shown in FIG.

The position of the boundary line is preferably at least 1 mm away from the start position of the plate fitting base portion 15 . The position of the boundary line J including the exposed portion 33 of the hard resin material and the bending behavior of the first covering portion 18 including the soft resin material are sharply changed. The starting position of the variable plate fitting base part 15 is staggered, so that the stress at the time of brushing can be relieved.

<Manufacturing method of toothbrush 1>

The toothbrush 1 of the present embodiment is produced by two-color molding with different materials on the primary side and the secondary side.

First, the base main body 11 is produced by injection molding using a hard resin material.

Next, a soft resin material is poured into the mold from the handle portion 16 side of the main body portion 11 which is a primary molded product, thereby producing the cover portion 12 .

At this time, after the inflowing soft resin material covers a predetermined area on the surface of the handle portion 16, the neck portion 14 is covered through the cutout portion 31 provided on the back side of the plate fitting base portion 15, and then the surface of the brush head portion 13 other than the flocking surface 19 is covered, thereby forming the covering portion 12 on the surface of the main body portion 11. In this way, the toothbrush 1 of this embodiment is produced.

Furthermore, in the present embodiment, the covering portion 12 is formed to cover the surface of the brush head 13 except the flocking surface 19, but it is not limited thereto, and the covering portion 12 may be formed by covering the surface of the brush head 13 including the flocking surface 19.

In addition, in the present embodiment, only one notch part 31 is provided, but a plurality of notch parts 31 may be provided.

In the toothbrush 1 for infants and young children, it is necessary to adopt a configuration in consideration of not stinging the throat during use. Therefore, the toothbrush 1 for infants is equipped with a puncture-resistant throat plate 20 at a predetermined position on the toothbrush body 10, and the length of the neck 14 is shorter than that of a toothbrush for adults. Therefore, the stress during tooth brushing tends to concentrate on the base of the neck 14 .

In addition, in a normal toothbrush without a puncture-resistant throat plate 20, stress is dispersed by the overall bending of the toothbrush. However, in the structure of the toothbrush 1 for infants and young children having the plate fitting base portion 15 on which the stab-resistant throat plate 20 is attached, the portion of the plate fitting base portion 15 is firm, and the load during brushing is easy to concentrate at the boundary portion with the neck portion 14 adjacent to the plate fitting base portion 15.

Therefore, securing the strength at this portion becomes a problem. This is a particularly important issue in the case of infants who are likely to bite the toothbrush during use.

Therefore, the toothbrush 1 of the present embodiment takes measures to alleviate the stress at the time of tooth brushing.

First, the toothbrush 1 of this embodiment is set as the structure which provided the covering part 12 normally provided only in the handle part 16 also in the neck part 14 and the head part 13. As shown in FIG. That is, the covering part 12 covers the surface of the brush head 13 or the neck 14 which is easy to be bitten by infants during use, thereby preventing bites. Thereby, it can be used without causing damage to the oral cavity. In addition, good hygiene can also be maintained. However, since it has a covered structure, the volume of the hard resin material becomes small, and it is more necessary to ensure the above-mentioned strength.

Therefore, in this embodiment, the notch part 31 is provided in the plate fitting base part 15 of the main body part 11 considering the point that the length of the neck part 14 is short because it is the toothbrush 1 for infants. Thereby, the second covering part 17 covering the handle part 16 and the first covering part 18 covering the head part 13 and the neck part 14 can be made into a continuous integral structure.

Thereby, each second covering part 17, the first covering part 17 including the soft resin material The boundary line between the part 18 and the main body part 11 made of hard resin material is not closed around the axis of the main body part 11, so compared with the structure in which the second covering part 17 is separated from the first covering part 18, the stress concentration at the boundary position can be relaxed.

That is, the second covering portion 17 and the first covering portion 18 are continuously formed through the notch portion 31 , whereby the stress during brushing is easily dispersed in the longitudinal direction of the toothbrush 1 . Therefore, it is preferable to provide the notch part 31 on the back surface side of the toothbrush 1 which is easy to receive the stress at the time of brushing.

In addition, by providing the notch portion 31 without forming a step in the first covering portion 18, the tensile stress applied to the second covering portion 17 can be dispersed.

In addition, the exposed portion 33 of the neck 14 is provided with a U-shaped stress relaxation portion 34, whereby the boundary line with the first covering portion 18 is formed in a U-shape. Compared with the structure in which the boundary line is formed in a circular shape around the axis of the neck 14, the stress during tooth brushing is easily dispersed in the long axis direction, and high strength can be obtained. In addition, if the U-shaped depth of the stress relieving portion 34 is set to be shallower than the above-mentioned range, it will be difficult to exert the effect of relieving stress, and if the U-shaped depth of the stress relieving portion 34 is set to be deeper than the above-mentioned range, the molding of the main body portion 11 will become difficult. Therefore, it is preferable to specify the size within the above-mentioned range.

In addition, the stress relieving part 34 provided on the front side of the neck 14 faces the back of the base of the neck 14 which is most likely to be loaded when brushing teeth, and can prevent the neck 14 of the main body 11 from breaking when an impact or the like is applied.

[Example of the first embodiment]

Hereinafter, the first embodiment of the present invention will be specifically described with examples, but the present invention is not limited by the following description.

In the evaluation, a toothbrush made of polypropylene as the primary material and olefin-based elastomer as the secondary material was used.

[Operation in the oral cavity]

A toothbrushing test was performed by five infants (and guardians) as testers, and the ease of operability in the oral cavity was evaluated on the basis of the following criteria.

"Assessment Benchmarks"

5: good

4: slightly better

3: not bad not bad

2: slightly worse

1: Poor

[strength of the neck]

Make the flocking surface 19 horizontal and upward, and hold and fix the handle part 16 of the toothbrush with a jig. After hanging the metal wire connected with 2 kg scales on the hair-planted surface 19, the scales were allowed to fall freely, and the maximum load (N) on the hair-planted surface 19 when the neck 14 was broken was measured (five-stage evaluation).

The average value of these measured values was classified into the following evaluation criteria, and the strength of the head part 13 was evaluated.

"Assessment Benchmarks"

5: Above 100N

4: More than 80N, less than 100N

3: More than 60N, less than 80N

2: More than 40N, less than 60N

1: Less than 40N

[Protection in the mouth (injury difficulty level)]

The degree of damage of the five used samples was visually evaluated, and an average score of five expert panelists was calculated on the basis of the following for each sample.

"Assessment Benchmarks"

5: No damage at all

4: There is one dent on the surface of the first covering part (elastomer)

3: There are many dents on the surface of the first covering part (elastomer)

2: There is one crack on the surface of the first covering part (elastomer)

1: There are many cracks on the surface of the first covering part (elastomer)

The specifications and evaluation results of the toothbrushes of Examples 1 to 10 are shown in Table 1, and the specifications and evaluation results of the toothbrushes of Examples 11 to 14 are shown in Table 2.

As shown in Table 1, the toothbrushes of Examples 1 to 14 have good operability in the oral cavity, are difficult to bite, and the oral cavity is fully protected, and the strength of the neck 14 and the handle 16 is also sufficiently ensured. Among these, especially the toothbrushes of Examples 1 to 10 obtained the above-mentioned effects on average.

The toothbrush of Example 1 was highly evaluated and balanced in terms of operability in the oral cavity, strength of the neck portion 14 and the handle portion 16 , and protection of the oral cavity.

Using the toothbrush of Example 1 as a reference, the toothbrush of Example 2 was highly evaluated in terms of operability in the oral cavity because the neck portion 14 (hard resin portion: core) was thinner than that of Example 1.

In the toothbrush of Example 3, since the neck 14 is thicker than that of Example 1, the strength of the neck 14 and the handle 16 is increased.

In the toothbrush of Example 4, compared with the structure of Example 1, the proportion of elastomer fat in the elastomer resin and polypropylene constituting the neck portion 14 is slightly smaller. The thickness of the neck 14 is the same as in Example 1, so the proportion of polypropylene in the neck 14 is slightly increased. Therefore, the strength of the neck portion 14 and the handle portion 16 is higher than that of the first embodiment.

In the toothbrush of Example 5, since the ratio of the elastomer resin in the neck portion 14 is larger than that of Example 1, the protection of the oral cavity can be sufficiently ensured.

In the toothbrush according to Example 6, the position of the boundary between the first covering portion 18 of the neck portion 14 and the insertion portion 15B of the plate fitting base portion 15 partially coincides. That is, the bottom of the recessed portion of the stress relieving portion 34 of the exposed portion 33 of the neck 14 reaches the surface 15b of the insertion portion 15B of the plate fitting base portion 15, and the first covering portion 18 exists in a part of the circumferential direction of the neck 14 and in the entire longitudinal direction of the neck 14. Even with such a configuration, effects close to that of Embodiment 1 can be obtained. In terms of the strength of the neck 14 and the handle 16 , it can be seen that the position of the boundary is preferably located on the brush head 13 side than the plate fitting base 15 in the entire circumferential direction of the neck 14 .

The toothbrush of Example 7 has no stress relaxation portion 34 structure. Even with such a configuration, effects close to that of Embodiment 1 can be obtained. In terms of the strength of the neck portion 14 and the handle portion 16, it can be seen that it is more desirable to have the stress relaxation portion 34.

The toothbrush of Example 8 has a structure in which the groove depth of the stress relaxation part 34 is shallow. Even with such a configuration, effects close to that of Embodiment 1 can be obtained. In terms of the strength of the neck portion 14 and the handle portion 16, it can be seen that the groove depth of the stress relief portion 34 is 0.8 mm. The above is more ideal.

The toothbrush of Example 9 has a structure in which the groove depth of the stress relaxation part 34 is deep. Even with such a configuration, effects close to that of Embodiment 1 can be obtained. From the viewpoint of the strength of the neck portion 14 and the handle portion 16, it can be seen that the groove depth of the stress relaxation portion 34 is more preferably 1.6 mm or less.

In the toothbrush of Example 10, the stress relieving part 34 is not located on the bristle-implanted surface 19 side, but is provided on both sides of the neck 14, respectively. Even with such a configuration, effects close to that of Embodiment 1 can be obtained. From the viewpoint of the strength of the neck portion 14 and the handle portion 16 , it can be seen that it is desirable that the stress relaxation portion 34 is located on the hair-implanted surface 19 side of the neck portion 14 .

In the toothbrush of Example 11, although the notch part 31 is not provided in the plate fitting base part 15, the operability in the oral cavity is good, and the protection effect in the oral cavity can be fully obtained.

In the toothbrush of Example 12, since the thickness of the neck portion 14 is thin, the operability in the oral cavity is very good.

In the toothbrush of Example 13, since the proportion of the elastomer resin constituting the neck portion 14 is large, the effect of protecting the inside of the oral cavity is high.

In the toothbrush of Example 14, since the proportion of polypropylene constituting the neck portion 14 is large, the strength from the neck portion 14 to the handle portion 16 is high.

As described above, in the toothbrush of the first embodiment, the thinner the neck portion 14 is, the better the operability in the oral cavity is, and the thicker the first covering portion 18 is, the more sufficient the protection of the oral cavity can be achieved. The strength of the neck 14 depends not only on the thickness of the neck 14 (thickness of polypropylene), but also on the notch 31 of the plate fitting base 15 The presence or absence of the neck 14, the position of the boundary between the first covering part 18 and the exposed part 33 (the position of the boundary between the elastomer resin and polypropylene), the position of the stress relaxation part 34, and the like.

[Second Embodiment]

Fig. 9A is a front view showing the structure of a toothbrush according to a second embodiment. Fig. 9B is a rear view showing the structure of the toothbrush according to the second embodiment. Fig. 10A is a front view showing the structure of a toothbrush body according to a second embodiment. Fig. 10B is a rear view showing the structure of the toothbrush body of the second embodiment. Fig. 11 is a partially enlarged view showing the configuration around the neck of the toothbrush body according to the second embodiment. Fig. 12 is a partially enlarged view showing the configuration around the neck of the toothbrush body according to the second embodiment.

As shown in FIGS. 9A and 9B , the toothbrush 40 of the second embodiment is configured as a toothbrush assumed to be used by children up to about eight months old. The toothbrush 40 includes a toothbrush body 40A and a second anti-stab throat plate 40B detachably attached to the toothbrush body 40A.

As shown in FIG. 10A and FIG. 10B , toothbrush main body 40A has head portion 43 , neck portion 44 , plate fitting base portion 45 , and handle portion 46 , and these parts are integrally formed in this order. The handle portion 46 of the present embodiment is formed in a ring shape so that even a baby can easily grasp it.

The toothbrush main body 40A includes a main body part 41 made of a hard resin material, and a coating part 42 made of a soft resin material that covers at least a part of the surface of the main body part 41 .

The main body 41 can be produced by injection molding, for example, using the same hard resin material as in the first embodiment.

The covering part 42 has the 1st covering part 48 which covers at least part of the surface of the neck part 44, and the 2nd covering part 47 which covers at least part or the whole surface of the handle part 46. As the soft resin material of the covering part 12, the same material as that of the first embodiment can be used.

Since the configuration of the second stab-resistant throat plate 40B is the same as that of the first embodiment, description thereof will be omitted.

(toothbrush body)

In the present embodiment, the object of use of the toothbrush 40 is an infant, so the overall length of the toothbrush main body 40A in the longitudinal direction is determined in consideration of the operability of the infant and the like. For example, it is preferably about 70 mm to 110 mm, more preferably about 80 mm to 100 mm.

As shown in FIGS. 11 and 12 , the brush head 43 is located at the front end of the main body 41 , and has a flocking surface 49A and a flocking surface 49B on both sides in the thickness direction. A plurality of hairs 43a made of a soft resin material are provided on each of the flocking surfaces 49A and 49B.

The material of the hair 43a is not particularly limited, and for example, polyamides such as 6-12 nylon and 6-10 nylon, polyesters such as PET, PBT, polytrimethylene terephthalate (PTT), PEN, polybutylene naphthalate (PBN), polyolefins such as PP, olefin-based elastomers, styrene-based elastomers, and synthetic resin materials such as silicone can be used. These resin materials may be used alone or in combination of two or more. In addition, since infants up to about eight months old sometimes bite the toothbrush during use, elastomer and silicone are preferable as the material of the hair.

The neck portion 44 is a portion extended from one end side of the brush head portion 43 . Specifically, as shown in FIG. 11, it is formed from the plan view shape of the brush head 43 and formed from the neck. The end point of the curve of the chamfered corner from the portion 44, that is, the position of the boundary P1 where the curve of the chamfered curve changes in the bending direction is the length L3 to the surface 45b of the insertion portion 45B.

The cross-sectional shape of the neck 44 is circular or elliptical, and its width is fixed or expanded along the length direction. The length of the neck 44 is determined in consideration of the size of the baby's oral cavity. In this embodiment, for example, as shown in FIG. 11 , the length L3 of the neck portion 44 is preferably about 2 mm to 7 mm, more preferably about 3 mm to 6 mm.

In addition, the range of the width and thickness (including the smallest diameter) of the thinnest part of the neck 44 and the range of the width and thickness (including the largest diameter) of the thickest part of the neck 44 are the same as those of the first embodiment. Furthermore, the dimensions of the width and thickness of the neck portion 44 include the dimensions of the thickness of the first covering portion 48 .

As shown in FIG. 10A and FIG. 10B , the handle portion 46 of this embodiment is formed in a ring shape, and is provided on one end side of the neck portion 44 (the end portion opposite to the end portion on the brush head portion 43 side). As in the first embodiment, if the handle portion 46 is defined from the end portion 41b of the main body portion 41 opposite to the end portion 41a on the brush head portion 43 side to the base 45a of the plate fitting base portion 45, the length L5 of the handle portion 46 shown in FIG. 10A is preferably about 60 mm to 70 mm, for example.

Alternatively, since the handle portion 46 is annular, the outer diameter D1 and the inner diameter D2 may be individually defined as shown in FIG. 10A . The difference between the outer diameter D1 and the inner diameter D2 of the handle portion 46 corresponds to the width W of the handle portion 46 when viewed from the front, and is set to a size that is easy for a baby to grasp. In addition, as shown in FIG. 12 , the width W of the handle portion 46 in a side view is formed to be wider than the width W2 of the neck portion 44 .

As shown in FIGS. 11 and 12 , the plate fitting base portion 45 is provided on the neck portion 44 Between the handle portion 46 and the central axis O of the toothbrush main body 40A, an annular shape is formed. The plate fitting base portion 45 has a plate fitting portion 45A, an insertion portion 45B located on the side of the brush head portion 43 of the plate fitting portion 45A, and a reinforcement portion 45C located on the side of the handle portion 46 of the plate fitting portion 45A, and is formed to expand concentrically in a direction perpendicular to the central axis O compared with the neck portion 44 and the handle portion 46 .

The plate fitting portion 45A, the insertion portion 45B, and the reinforcement portion 45C have different diameters, and the plate fitting portion 45A has the largest diameter. The diameters of the insertion portion 45B and the reinforcement portion 45C may be the same or different. The insertion portion 45B is a portion where the stab-resistant throat plate 20 is fitted, and therefore must match the diameter of the through hole 21 . However, the plate fitting base portion 45 is a portion provided to ensure the strength of the neck portion 44 , so the diameter is not particularly specified.

The diameter of the insertion portion 45B and the thickness of the insertion portion 45B in the longitudinal direction are the same as those of the first embodiment. Also, the diameter of the plate fitting portion 45A and the thickness of the plate fitting portion 15A in the longitudinal direction are the same as those of the first embodiment.

In the plate fitting base part 45 of this embodiment, the front (the surface on the flocking surface 49A side) side shown in FIG. 10A and the back (the surface on the flocking surface 49B side) side shown in FIG.

The notch part 31 and the depth of the notch part 31 are preferably the depth at which the convex shape of the plate fitting base part 45 disappears, similarly to the first embodiment. In this embodiment, the respective bottom surfaces of the notch portion 31 and the notch portion 31 also become the same as the respective surfaces of the handle portion 46 and the neck portion 44, so as to connect the surface of the handle portion 46 with the surface of the neck portion 44. Surfaces connect smoothly.

The dimensions of the width and depth of the notch 31 are the same as those of the first embodiment.

As shown in FIGS. 9A and 9B , the second covering portion 47 covers substantially the entire handle portion 46 . In this embodiment, an opening 47a is provided in the second covering part 47, and a part of the main body part 41 is exposed from the opening 47a. The presence, shape, etc. of the opening 47a can be changed as appropriate.

As shown in FIGS. 10A and 10B , the first covering portion 48 covers at least a part of the neck portion 44 over its entirety in the circumferential direction. In this embodiment, the entirety of the axis around the central axis O ( FIGS. 11 and 12 ) at the front end side of the brush head 43 side of the neck portion 44 is covered by the first covering portion 48 . In this embodiment, for example, when the entire length of the neck 44 in the longitudinal direction is taken as 100%, the entire circumference of the neck 44 is covered by the first covering portion 48 in at least 40% or more of the region. The biting of the brush head 43 and the neck 44 can be prevented by the first covering part 48 , and it is more preferable if the covering range is more than 50%.

In addition, the first covering portion 48 is provided so as to cover substantially the entirety of the brush head 43 including the flocking surface 49A and the flocking surface 49B, and each notch 31 provided on the front and back of the neck 44 and a part of the area inside the notch 31 .

In this embodiment, for example, about 60% or more of the total surface area of the neck portion 44 is covered by the first covering portion 48 . The biting of the brush head 43 and the neck 44 can be prevented by the first covering part 48, and it is more preferable if the covering range is more than 65%.

The second covering part 47 and the first covering part 48 are continuous through a pair of notches 31, 31 provided on the plate fitting base part 45, and are integrally formed with each other to constitute the present embodiment. The covering part 42 of embodiment. The thickness of the covering part 42 is set to the minimum thickness which feels soft when bitten and hardly causes damage. The thickness of the covering portion 42 is the same as that of the first embodiment.

In this embodiment, as shown in FIGS. 11 and 12 , a part of the neck 44 on the side of the plate fitting base portion 45 , each cutout portion 31 in the plate fitting base portion 45 , a part of the surface inside the cutout portion 31 , and a part of the handle portion 46 on the side of the plate fitting base portion 45 become the exposed portion 53 that is not covered by the first covering portion 48 and the second covering portion 47 . In addition, the surface of the board fitting base part 45 is not covered with any one of the 1st covering part 48 and the 2nd covering part 47. As shown in FIG.

The exposed portion 53 has a pair of stress relieving portions 54 , 54 on the boundary side with the first covering portion 48 . The pair of stress relieving portions 54 , 54 are respectively provided on the side surfaces of both sides of the toothbrush body 40A, and are located at positions offset from the positions of the surrounding axis and the notch 31 and the notch 31 .

As shown in FIG. 11 , each stress relieving portion 54 and the boundary between the stress relieving portion 54 and the first covering portion 48 have a Y-shape extending toward the handle portion 46 through the notch portion 31 and the notch portion 31 when viewed from the front and back of the toothbrush body 40A, respectively, and protruding toward the brush head 43 side.

As shown in FIG. 11 , the Y-shape of the stress relieving portion 54 is located at the front end of the stress relieving portion 54 on the brush head 43 side, and the radius R1 when viewed from the front is preferably about 0.5 mm to 3.5 mm, for example. In addition, as shown in FIG. 12 , the radius R2 when viewing the tip of the stress relaxation portion 54 from the side is preferably, for example, about 1.0 mm to 2.5 mm.

Furthermore, the Y-shape of the stress relieving portion 54 can also be a plurality of curves with different radii. line connection to form.

As in this embodiment, when the flocking surface 49A and the flocking surface 49B are respectively provided on the front and back sides of the toothbrush, by providing the stress relieving part 54 and the stress relieving part 54 on the front side and the back side respectively, the stress concentration toward the neck 44 during use can be alleviated even when a baby who has difficulty distinguishing the front and back uses the bristles on either side of the front and back.

As shown in FIG. 11 , at the front end side of the Y-shaped stress relieving portion 54, that is, at the front end of the stress relieving portion 54 on the brush head 43 side, the point M where the curve of the two strands becomes a straight line is preferably located on the brush head 43 side compared with the starting position of the plate fitting base portion 45. The starting position of the plate fitting base part 45 is the position of the surface 45b of the insertion part 45B seen from the front side of the toothbrush 40. As shown in FIG.

The depth T2 of the Y-shaped both legs of the stress relieving portion 54 corresponds to the length from the starting point of the stress relieving portion 54 on the brush head 43 side to the above-mentioned point M. As shown in FIG. The Y-shaped depth T2 is, for example, preferably within a range of 1.0 mm to 3.5 mm, more preferably 2.0 mm to 3.0 mm. By setting the Y-shaped depth T2 within the above-mentioned range, concentrated stress can be relaxed and sufficient strength can be ensured for the boundary portion between the neck portion 44 and the plate fitting base portion 45 where the bending behavior of the first covering portion 48 made of the soft resin material changes rapidly.

In addition, as shown in FIG. 11 , the length L4 of the Y-shaped rear end of the stress relieving portion 54 is at least 10 mm or more, for example, preferably within a range of 10 mm to 12 mm. The length L4 is the length of the straight line portion of the stress relieving portion 54 on the handle portion 46 side, and corresponds to the distance from the point M to the boundary point N between the plate fitting base portion 45 and the handle portion 46 .

As shown in FIG. 11 , the distance L6 from the converging point M of the two Y-shaped portions of the stress relieving portion 54 to the surface 45b of the insertion portion 45B is preferably 1 mm or more. That is, the position of the converging point M of the two Y-shaped portions of the stress relieving portion 54 is preferably separated from the starting position of the plate fitting base portion 45 by 1 mm or more. Stress at the time of brushing can be relieved by shifting the converging point M of both Y-shaped legs of the stress relieving portion 54 from the starting position of the plate fitting base portion 45 where the bending behavior changes rapidly.

In addition, the stress relaxation portion 54 shown in FIG. 12 has a width W3 of a starting point on the neck 44 side and is formed to have the same width W2 as that of the neck 44 .

In the toothbrush 1 for infants, it is configured so as not to irritate the throat during use, and since the oral cavity of infants is smaller than that of infants, and deciduous teeth are not fully formed, it is necessary to adopt a structure that is gentle on the gums. In addition, it is also important to have a structure that is easy to grasp even if the grip is weak.

Therefore, in this embodiment, the length of the neck 44 is shorter than that of a toothbrush for infants in comparison with the size of the baby's oral cavity, and the shape of the handle is also ring-shaped, so that the baby can hold it by itself from any angle. In addition, the bristles made of soft resin material are provided on the front and back sides of the brush head 43, so that even babies who have difficulty judging the front and back can clean the teeth on either side of the brush head 43 by biting the brush head 43. In addition, the soft resin material is used to form the bristle portion, so that it is gentle on the gums and does not cause damage to the oral cavity.

As mentioned above, the baby toothbrush 40 has the anti-stab throat plate 20 attached to the predetermined position of the toothbrush body 40A, but in the structure having the plate fitting base portion 45 on which the stab-proof throat plate 20 is attached, the portion of the plate fitting base portion 45 is firm and hard to bend. in addition, Since the length of the neck 44 is extremely short compared with a toothbrush for adults, stress during tooth brushing tends to concentrate on the base of the neck 44 .

Therefore, in the present embodiment, be made as following structure: Contrast the bristle portion of the front and back of the brush head 43, on either side of the front and back of the neck 44, the notch part 31 and the stress relaxation part 54 are respectively provided, and the stress during brushing can be eased.

In addition, the strength around the neck can be enhanced by adopting a configuration in which the plate fitting base portion 45 is configured in three stages and a reinforcing portion 45C is further provided at the base of the handle portion 46 side.

[Example of the second embodiment]

Hereinafter, the second embodiment of the present invention will be specifically described with examples, but the present invention is not limited by the following description.

In the evaluation, a toothbrush made of polypropylene as the primary material and olefin-based elastomer as the secondary material was used.

[Operation in the oral cavity]

A toothbrushing test was conducted with five infants as testers, and the ease of operability in the oral cavity was evaluated from the viewpoint of the caretaker on the basis of the following criteria.

"Assessment Benchmarks"

5: Good

4: slightly better

3: not bad not bad

2: slightly worse

1: Poor

[strength of the neck]

The flocking surface 49A is made to be horizontal and upward, and the handle part 46 of the toothbrush is held and fixed with a jig. After hanging the metal wire connected with the 2 kg scale on the flocking surface 49A, the scale was freely dropped, and the maximum load (N) to the flocking surface 49A when the neck 44 was broken was measured (n=5). The average value of these measured values was classified into the following evaluation criteria, and the strength of the brush head part 43 was evaluated.

"Assessment Benchmarks"

5: Above 100N

4: More than 80N, less than 100N

3: More than 60N, less than 80N

2: More than 40N, less than 60N

1: Less than 40N

[Protection in the mouth (injury difficulty level)]

The degree of damage of the five used samples was visually evaluated, and an average score of five expert panelists was calculated on the basis of the following for each sample.

"Assessment Benchmarks"

5: No damage at all

4: There is one dent on the surface of the first covering part (elastomer)

3: There are many dents on the surface of the first covering part (elastomer)

2: There is one crack on the surface of the first covering part (elastomer)

1: There are many cracks on the surface of the first covering part (elastomer)

The specification and evaluation result of the toothbrush of embodiment 1～embodiment 9 are shown in table 3.

As shown in Table 3, the toothbrushes of Examples 1 to 8 have good operability in the oral cavity, are difficult to bite, and the oral cavity is fully protected, and the strength of the neck 44 and the handle 46 is also sufficiently ensured. Among them, the toothbrush of Example 1 was highly evaluated in each item.

The toothbrush of Example 1 was highly evaluated and balanced in terms of operability in the oral cavity, strength of the neck portion 44 and the handle portion 46 , and protection of the oral cavity.

Using the toothbrush of Example 1 as a reference, the toothbrush of Example 2 obtained the same evaluation as that of Example 1 regarding intraoral operability and intraoral protection. Regarding the strength of the neck portion 44, it can be seen that it is more desirable to have the notch portion 31.

In the toothbrush of Example 3, the position of the boundary between the first covering portion 48 of the neck portion 44 and the insertion portion 45B of the plate fitting base portion 45 partially coincides, and the stress relieving portion 54 is not included. Even with such a configuration, the same evaluation as in Example 1 was obtained regarding intraoral operability and intraoral protection. Regarding the strength of the neck portion 44, it can be seen that it is more desirable to have the notch portion 31.

Example 4 is a configuration without the stress relaxation portion 54 . Even with such a configuration, the same evaluation as in Example 1 was obtained regarding intraoral operability and intraoral protection. Regarding the strength of the neck portion 44, it can be seen that it is more desirable to have the stress relaxation portion 54.

The toothbrush of Example 5 has a structure in which the length of the Y-shaped bifurcated part is 1.0 mm and short. Even with such a configuration, the same evaluation as in Example 1 was obtained regarding intraoral operability and intraoral protection.

The toothbrush of Example 6 has a Y-shaped two-pronged portion with a length of 3.9 mm and a long configuration. In the case of this constitution, regarding intraoral operability or intraoral protection, The same evaluation as in Example 1 was obtained, and regarding the strength of the neck portion 44 , a higher evaluation than in Example 1 was obtained.

From Example 5 and Example 6, it can be seen that in order to increase the strength of the neck portion 44, it is preferable that the length of the Y-shaped two-pronged portion be long.

In the toothbrush of Example 7, compared with the toothbrush of Example 1, the thickness of the neck body including the primary resin in the neck 44 is thinner at 4 mm, so the evaluation of intraoral operability and intraoral protection is high.

In the toothbrush of Example 8, the thickness of the neck 44 (neck body) is thick at 7 mm, and thus the strength of the neck 44 was highly evaluated.

From Examples 7 and 8, it can be seen that the strength of the neck 44 is in a trade-off relationship with the operability in the oral cavity and the protection of the oral cavity, and it is desirable to set the thickness of the neck 44 in terms of a balance between the two.

In the toothbrush of Example 9, the length of the first covering portion 48 is 30% of the total length of the neck portion 44 . In the case of this configuration, the same evaluation as in Example 1 was obtained regarding the operability in the oral cavity, but the evaluation of the strength of the neck portion 44 and the protection of the oral cavity was considerably lower than in Example 1. Therefore, regarding the strength of the neck 44 and protection of the oral cavity, it is desirable that the length of the first covering portion 48 is 40% or more of the total length of the neck 44 .

As described above, in the toothbrush of the second embodiment, the thinner the neck portion 44, the better the operability in the oral cavity, and when the thickness of the first covering portion 48 is 0.8 mm, the oral cavity can be sufficiently protected. The strength of the neck 44 depends not only on the thickness of the neck 44 (thickness of polypropylene), but also on the plate fitting base The presence or absence of the notch part 31 of the part 45, the position of the boundary between the elastomer resin and the polypropylene of the neck part 44, the position of the stress relaxation part 54, the length of the two-leg part of the Y shape, and the like.

As mentioned above, although preferred embodiment of this invention was demonstrated referring the accompanying drawing, it is needless to say that this invention is not limited to the said example. Those skilled in the art can obviously think of various modifications or amendments within the scope of the technical ideas described in the scope of the patent application, and understand that these modifications or amendments naturally also belong to the technical scope of the present invention.

In the first embodiment and the second embodiment, the toothbrush body and the anti-stab throat plate are set as different components, and the anti-stab throat plate is detachably mounted on the toothbrush body, but the toothbrush body and the anti-stab throat plate may also be integrated.

In the first embodiment, the plate fitting base portion 15 of the toothbrush body 10 is configured in two stages (the plate fitting portion 15A, the insertion portion 15B), but it may also be composed of only one stage (only the plate fitting portion 15A or the insertion portion 15B), or may be composed of three or more stages as in the second embodiment. In this case, it is preferable to specify the diameter or the like at the base portion with the largest diameter. In addition, in 2nd Embodiment, the structure of the plate fitting base part 45 is not limited to the said structure, For example, it may include one stage or two stages.

In addition, the shape of the stress relieving portion is not limited to the shape shown in each of the above-mentioned embodiments, for example, a U-shaped stress relieving portion and a Y-shaped stress relieving portion may be combined.

1: Toothbrush

10: Toothbrush body

11: Main body

12: cladding department

13: brush head

13a: Hair planting department

13A: Brush head body

14: Neck

14A: Neck body

15b, 20a: surface

15B: Insertion part

16: handle part

16A: Handle body

19: Flocking surface

19b: hair bundle

20: Anti-stab throat plate

Claims (13)

A toothbrush, characterized in that it comprises: a toothbrush body and a puncture-resistant throat plate arranged on the toothbrush body, the toothbrush body has a body part comprising a hard resin material and a first covering part comprising a soft resin material, the body part comprises: a brush head with a flocking surface; a neck extending from the rear end of the brush head; a handle part located on the opposite side of the neck and the brush head; and a plate fitting base part arranged between the neck and the handle; A part of the surface is provided with a notch part in the circumferential direction of the plate fitting base part, and the first covering part and the second covering part covering at least a part of the handle part are continuous and integrated through the notch part. The toothbrush according to claim 1, wherein the board fitting base part has: a fitting part fitted to the board side fitting receiving part of the puncture-resistant throat plate; and an insertion part inserted into a through hole of the board side fitting receiving part; the cutout part passes through the fitting part and the insertion part. The toothbrush according to claim 1, wherein an exposed portion is present at an end portion of the neck on the side of the handle portion, the exposed portion is adjacent to the plate fitting base portion and is not covered by the first covering portion. The toothbrush according to claim 3, wherein the exposed portion has at least one stress relieving portion on the boundary side with the first covering portion, and the boundary between the stress relieving portion and the first covering portion forms a U-shape concave toward the handle portion. The toothbrush according to claim 4, wherein when the total length of the neck in the longitudinal direction is taken as 100%, the first covering part covers the entire circumferential direction of the neck in at least 60% or more of the region. The toothbrush according to claim 4, wherein the U-shaped depth of the stress relieving portion is within a range of not less than 0.8 mm and not more than 1.6 mm. The toothbrush according to claim 3, wherein the exposed portion has at least one stress relieving portion on the boundary side with the first covering portion, and the boundary between the stress relieving portion and the first covering portion forms a Y-shape concave toward the handle portion side, the first covering portion and the second covering portion covering at least a part of the handle portion are continuous through the cutout portion, and are integrated with each other. The toothbrush according to claim 7, wherein the cross-sectional shape of the neck is circular or elliptical, and the width is fixed or enlarged in the longitudinal direction. When the total length of the neck in the longitudinal direction is set as 100%, the first covering part covers the entire circumferential direction of the neck in at least 40% of the region. The toothbrush according to claim 7, wherein the Y-shaped depth of the stress relieving portion is within a range of not less than 1.0 mm and not more than 3.5 mm. The toothbrush as claimed in item 4, wherein the stress relieving part is set It is placed on the same side as the flocking surface in the circumferential direction of the neck. The toothbrush according to claim 4, wherein a starting point of the neck side of the stress relieving portion is formed with the same width as the neck. The toothbrush according to claim 1, wherein the minimum value of the width and thickness of the neck is not less than 4.0 mm and not more than 7.0 mm. The toothbrush according to claim 1, wherein the surface of the brush head is covered by the first covering part.

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