JP7142567B2 - toothbrush - Google Patents

Description

The present invention relates to toothbrushes.

Since habituation of plaque control from childhood greatly affects oral health throughout life, it is necessary to acquire appropriate brushing techniques. However, since infants are not accustomed to brushing their teeth, care must be taken to avoid accidental swallowing of the toothbrush or stabs in the throat due to falls. In addition, there is a concern that unevenness and burrs may occur on the surface of the toothbrush and the oral cavity may be damaged by biting the toothbrush during brushing.

As a measure to prevent throat piercing with a toothbrush, a ``anti-throat piercing toothbrush'' is already on the market, in which a large ring-shaped throat piercing prevention plate is fitted to the base of the neck of the toothbrush to prevent the toothbrush from being swallowed. (For example, Patent Document 1).

On the other hand, as a measure to prevent bites on the toothbrush, the head part made of a hard resin material (primary resin) such as polypropylene and the neck part are covered with a soft resin material (secondary resin) such as elastomer. , there are techniques to prevent scratches on the surface. This measure has the advantage that even if the primary side resin is broken, the surface is covered with the secondary side resin, so it is difficult to expose the sharp fracture surface, and it is commonly used (for example, , Patent Document 2).

Japanese Utility Model Laid-Open No. 57-162732 Japanese Patent No. 5830277

However, when the above measure of coating the primary side resin with the secondary side resin is applied to the neck portion of the toothbrush, it becomes a so-called double-core structure, which makes it difficult to increase the volume of the primary side resin, resulting in strength. A problem arises in terms of In particular, toothbrushes for infants with small oral cavities have restrictions on the size of the head portion and the diameter of the neck portion of the toothbrush, so measures other than increasing the amount of the primary resin are required.

Moreover, if the above-described double-core structure is applied to a "toothbrush that prevents sticking to the throat," the technical difficulty in terms of strength becomes even higher. In the "toothbrush that prevents sticking in the throat," a separate plate for preventing sticking in the throat is fitted to the base of the neck, so it is necessary to form a base made of primary resin at the attachment site. However, during use of the toothbrush, stress concentration is likely to occur at the joint between the base and the neck. Considering that baby toothbrushes generally tend to have a short neck length, the stress concentration during brushing is further increased.

As described above, the toothbrush for infants having the "thrust-stabbing prevention plate" as a throat-stabbing prevention measure and the "elastomer coating" as a biting prevention measure has a serious problem in terms of strength.

One aspect of the present invention has been made in view of the above-mentioned problems of the prior art, and provides a high-strength toothbrush that prevents throat stabs and bites during use and prevents stress concentration during brushing. intended to provide

A toothbrush according to one aspect of the present invention includes a toothbrush body and a throat attachment prevention plate provided on the toothbrush body, wherein the toothbrush body includes a head portion having a flocking surface and a rear end of the head portion. Made of a hard resin material having a neck portion, a handle portion located on the opposite side of the neck portion from the head portion, and a plate fitting base portion disposed between the neck portion and the handle portion. It is characterized by comprising a body portion and a first covering portion made of a soft resin material covering at least a part of the surface of the neck portion.

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

In the toothbrush according to one aspect of the present invention, the plate fitting base portion includes a fitting portion that fits into the plate side fitting receiving portion of the throat prevention plate, and a through hole of the plate side fitting receiving portion. and an insertion portion to be inserted into the insertion portion, and the notch portion may pass through the fitting portion and the insertion portion.

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

In one aspect of the toothbrush of the present invention, the exposed portion has at least one stress relaxation portion on the boundary side with the first covering portion, and the stress relaxation portion and the first covering portion may be configured to form a U-shape recessed toward the handle portion side.

In one aspect of the toothbrush of the present invention, the first covering portion covers the entire circumferential direction of the neck portion in an area of at least 60% or more when the total length of the neck portion in the length direction is taken as 100%. It is good also as the structure which has.

In one aspect of the toothbrush of the present invention, the U-shaped depth of the stress relaxation portion may be in the range of 0.8 mm or more and 1.6 mm or less.

In one aspect of the toothbrush of the present invention, the exposed portion has at least one stress relaxation portion on the boundary side with the first covering portion, and the stress relaxation portion and the first covering portion forming a Y-shaped boundary recessed toward the handle portion, and the first covering portion and the second covering portion covering at least a portion of the handle portion are connected through the notch, It is good also as a structure integrated mutually.

According to one aspect of the present invention, the neck portion has a circular or elliptical cross-sectional shape and a width that is constant or widens in the length direction, and the first covering portion has the width along the length direction. When the total length of the neck portion is taken as 100%, it may be configured such that at least 40% or more of the entire length of the neck portion in the circumferential direction is covered.

In one aspect of the toothbrush of the present invention, the Y-shaped depth of the stress relaxation portion may be in the range of 1.0 mm or more and 3.5 mm or less.

In one aspect of the toothbrush of the present invention, the stress relaxation portion may be provided on the same side as the bristle-implanted surface in the circumferential direction of the neck portion.

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

According to one aspect of the present invention, the minimum width and thickness of the neck portion may be 4.0 mm or more and 7.0 mm or less.

According to one aspect of the present invention, the surface of the head portion may be covered with the first covering portion.

Effect of the Invention According to the present invention, it is possible to provide a high-strength toothbrush that prevents throat stabs and bites during use and prevents stress concentration during brushing.

1 is a perspective view showing the overall configuration of the toothbrush of the first embodiment; FIG. FIG. 2 is a front view showing the configuration of the toothbrush main body of the first embodiment; FIG. 2 is a side view showing the configuration of the toothbrush main body of the first embodiment; FIG. 2 is a rear view showing the configuration of the toothbrush main body of the first embodiment; FIG. 2 is an enlarged view showing a part of the neck portion of the first embodiment; FIG. 2 is a front view showing the configuration of the throat-stabbing prevention plate of the first embodiment; FIG. 2 is a perspective view showing the configuration of the throat-strike prevention plate of the first embodiment from the back side; FIG. 2 is a cross-sectional view showing a boundary portion between the main body and the covering portion of the first embodiment; The front view which shows the structure of the toothbrush of 2nd Embodiment. The rear view which shows the structure of the toothbrush of 2nd Embodiment. The front view which shows the structure of the toothbrush main body of 2nd Embodiment. The rear view which shows the structure of the toothbrush main body of 2nd Embodiment. The partial enlarged view which shows the structure around the neck part of the toothbrush main body of 2nd Embodiment. The partial enlarged view which shows the structure around the neck part of the toothbrush main body of 2nd Embodiment.

Hereinafter, the structure of the toothbrush of each embodiment which concerns on this invention is demonstrated.
In addition, in each drawing below, in order to make each component easy to see, the scale of the dimensions may be changed depending on the component.

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

A toothbrush 1 of the present embodiment shown in FIG. 1 is configured assuming a toothbrush used by a child of about 6 months to 2 years old. The toothbrush 1 includes a toothbrush body 10 and a throat-strike prevention plate 20 detachably attached to the toothbrush body 10. - 特許庁

The toothbrush main body 10 has an elongated shape as a whole, and includes a main body portion 11 made of a hard resin material and a covering portion 12 made of a soft resin material that covers at least a part of the surface of the main body portion 11. ing.
The body portion 11 is composed of a head portion body 13A, a neck portion body 14A, a plate fitting base portion 15 (FIG. 2), and a handle portion body 16A, which are integrally formed in this order.

The body portion 11 can be produced, for example, by injection molding using a hard resin material.
Examples of constituent materials of the main body 11 include polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polycyclohexylene dimethylene terephthalate (PCT), polyacetal (POM), polyethylene naphthalate (PEN), Polystyrene (PS), acrylonitrile-butadiene-styrene resin (ABS), cellulose propionate (CP), polyarylate, polycarbonate, acrylonitrile-styrene copolymer resin (AS), and the like. Among these resin materials, materials such as POM, PBT, and PEN are preferably used because they have high strength and facilitate thinning of the head portion 13 . In addition, said resin may be used individually by 1 type of resin, and may use 2 or more types of resin together.

As shown in FIG. 8, the body portion 11 has a first surface 11A that is not covered with the covering portion 12 and is exposed to the outside, a second surface 11B that is covered with the covering portion 12, and a main body portion 11 and the covering portion. and a stepped portion 11</b>F formed at the boundary portion with 12 .

The covering portion 12 comprises a first covering portion 18 covering at least a portion of the surface of the neck portion main body 14A and a second covering portion 17 covering at least a portion or the entire surface of the handle portion main body 16A. Become.

As the soft resin material of the covering portion 12, for example, a resin having a Shore A value of 90 or less is preferable, and a resin having a Shore A value of 30 to 80 is more preferable. Examples of such soft resin materials include elastomer resins such as polyolefin-based elastomers, styrene-based elastomers, polyester-based elastomers, polyurethane-based thermoplastic elastomers, and silicon. When using a flexible resin such as an elastomer, for example, polyolefin is preferable from the viewpoint of improving adhesion, and polypropylene is more preferable as the hard resin material in that case.

(Throat prevention plate)
First, the configuration of the throat-strike prevention plate 20 will be described in detail.
FIG. 6 is a front view showing the configuration of the throat-strike prevention plate 20 of the first embodiment. FIG. 7 is a perspective view showing the structure of the throat-butting prevention plate 20 of the first embodiment from the rear surface 20b side. FIG. 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 throat-strike prevention plate 20 has a disc shape as a whole, and has an arbitrary design 22 on the surface 20a side. The throat-strike prevention plate 20 has a curved shape from the center to the periphery, and the front surface 20a side is convex and the back surface 20b side is concave. The outer diameter of the throat-butting prevention plate 20 is preferably about 45 mm to 55 mm in terms of throat-butting prevention and operability. Although the throat-stabbing prevention plate 20 may be made of the above hard material, it is more preferable to be made of the above-mentioned soft resin material in order to prevent throat pokes and bites during use.

A through hole 21 concentric with the central axis O is formed in the center of the throat-strike prevention plate 20 . A diameter d1 of the through-hole 21 is preferably about 12 mm to 15 mm.

A plate-side fitting receiving portion 23 concentric with the central axis O is provided on the back surface 20b side of the throat-butting prevention plate 20 . The plate-side fitting receiving portion 23 has a cylindrical shape. The diameter d2 of the plate-side fitting receiving portion 23 is preferably about 16 mm to 20 mm. Further, 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 more preferably about 0.65 to 0.80. .

Within the above range, the contact area of the throat-butting prevention plate 20 with both the plate fitting portion 15A and the insertion portion 15B increases, and the throat-butting prevention plate 20 is stably perpendicular to the longitudinal direction of the toothbrush. Easier to fix. In particular, when the throat-strike prevention plate 20 is made of a soft resin material, the effects as described above are exhibited more effectively.

(Toothbrush body)
Next, the configuration of the toothbrush body 10 will be described in detail.
In the present embodiment, since the target users of the toothbrush 1 are infants, the overall length of the toothbrush body 10 in the longitudinal direction is determined in consideration of operability by infants, and is, for example, about 100 mm to 140 mm. preferable.

As shown in FIGS. 2 to 4, the head portion 13 is positioned on the tip side of the body portion 11 and has a flocked surface 19 on one side in the thickness direction. The head portion 13 is provided with a plurality of flocking portions 13a (FIG. 1), and a plurality of hairs of a predetermined length are bundled in each of a plurality of circular flocking holes 19a formed in the flocking surface 19. A bundle of hair 19b is planted.

The material of the bristles constituting the bristles 19b is not particularly limited, and examples include polyamides such as 6-12 nylon and 6-10 nylon, PET, PBT, polytrimethylene terephthalate (PTT), PEN, and polybutylene. Synthetic resin materials such as polyester such as phthalate (PBN), polyolefin such as PP, olefin elastomer, and styrene elastomer can be used. These resin materials may be used singly or in combination of two or more.

The neck portion 14 is a portion extending from one end side of the head portion 13 .
Specifically, from the end point of the curve forming the corner cut from the neck portion 14 in the plan view shape of the head portion 13, that is, from the position of the boundary P1 where the bending direction of the curve forming the corner cut changes, the insertion portion It is the length L1 to the surface 15b of 15B. The neck portion 14 has a circular or elliptical cross-sectional shape, and its width is constant or widens along its length.

The length of the neck portion 14 is determined in consideration of the intraoral size of the infant. 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.

The width and thickness dimensions (minimum diameter) of the thinnest portion of the neck portion 14 are preferably about 4.0 mm to 7.0 mm, more preferably 5.0 mm to 7.0 mm. . The width and thickness dimensions (maximum diameter) of the thickest portion 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. . The width and thickness dimensions of the neck portion 14 described above are dimensions including the thickness of the first covering portion 18 .

The handle portion 16 is a portion that extends from one end side of the neck portion 14 (the end portion opposite to the end portion on the head portion 13 side) and is a portion that is gripped by the user. In the present embodiment, the handle portion 16 is defined from the end portion 11b of the body portion 11 opposite to the end portion 11a on the head portion 13 side to the base portion 15a of the plate fitting base portion 15 . The width of the handle portion 16 is wider than the width of the neck portion 14 . Also, 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 provided between the neck portion 14 and the handle portion 16, and has a length L2 along the longitudinal direction (from the surface 15b of the insertion portion 15B to the plate), for example, in consideration of preventing an infant from getting stuck in the throat. The distance to the base 15a of the fitting portion 15A) is preferably within the range of 4 mm to 8 mm.

Furthermore, it is more preferable that the surface 15b of the insertion portion 15B be provided at a position 30 mm to 55 mm from the tip of the head portion 13. FIG. 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 with diameters different from each other, and is formed to expand concentrically outward from the neck portion 14 and the handle portion 16 in the minor axis direction. there is

The insertion portion 15B is located on the neck portion 14 side of the plate fitting base portion 15, and is a portion that is inserted into a through hole 21 of the throat-butting prevention plate 20, which will be described later. It is preferable that the diameter of the insertion portion 15B is approximately the same as the diameter of the through hole 21 . In order to ensure waterproofness, it is desirable that the gap between the insertion portions 15B inserted into the through-holes 21 is small.

Further, it is preferable that the surface 15b of the insertion portion 15B and the surface 20a of the throat-strike prevention plate 20 are substantially flush with each other when the insertion portion 15B is inserted into the through-hole 21 . By eliminating the step between the surface 20a of the throat-strike prevention plate 20 and the surface 15b of the insertion portion 15B, it is difficult for water to accumulate, and it can be used hygienically.

The plate fitting portion 15A is located on the handle portion 16 side of the plate fitting base portion 15 . The plate fitting portion 15A has a larger diameter than the insertion portion 15B and is a portion that fits into the plate-side fitting receiving portion 23 of the throat-butting prevention plate 20 .

The diameter of the insertion portion 15B of the plate fitting base portion 15 corresponds to the diameter d1 of the through hole 21 of the throat attachment prevention plate 20 described above, and is set within the range of 12 mm to 15 mm. In addition, the thickness of the insertion portion 15B in the longitudinal direction is set 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 throat attachment prevention plate 20 described above, and is set within the range of 16 mm to 20 mm. Further, the thickness of the plate fitting portion 15A in the longitudinal direction is set to be within the range of 4.0 mm to 6.0 mm.

The plate fitting base portion 15 is provided with a notch portion 31 axially penetrating the insertion portion 15B and the plate fitting portion 15A described above in a part of the circumferential direction. The notch portion 31 is a portion cut out toward the center of the plate fitting base portion 15 and is provided on the back side of the toothbrush main body 10 (the surface opposite to the flocking surface 19). It is preferable that the cutout depth of the notch portion 31 is such that the convex shape of the plate fitting base portion 15 disappears. In this embodiment, the bottom surface of the notch portion 31 is flush with the surfaces of the handle portion 16 and the neck portion 14 so as to connect the surfaces of the handle portion 16 and the neck portion 14 smoothly.

The width of the notch 31 is preferably in the range of 1.5 mm to 6.0 mm, more preferably 2.0 mm to 5.0 mm. By setting it within the above range, the contact area between the throat-butting prevention plate 20 and the plate fitting base portion 15 can be ensured, and the throat-butting prevention plate 20 can be more stably fixed to the toothbrush body. In addition, stress concentration, which will be described later, can be alleviated. The depth of the notch 31 corresponds to the flange width of the plate fitting portion 15A, and is within the range of 3.0 mm to 7.0 mm.

As shown in FIGS. 2, 3, and 4, the second covering portion 17 covers the rear surface 16c of the handle portion 16 and the side surfaces 16b, 16b on both sides, except for the surface on the rear end side of the handle portion 16. , and a part of the front face 16a (edges on the sides 16b, 16b) are provided so as to cover them continuously. Since at least a part of or the entire surface of the handle portion 16 is covered with the second covering portion 17 in this way, the hand fit feeling when the user grips the handle portion 16 is improved, and the grip is improved. You can prevent your fingers from slipping.

The first covering portion 18 covers the entire surface of the head portion 13 except for the flocked surface 19 and the entire surface of the neck portion 14 except for a partial area on the base end side. It is provided so as to cover the entire circumference of a part of the surface in the circumferential direction. In this embodiment, for example, when the total length of the neck portion 14 in the length direction is taken as 100%, at least 60% or more of the area of the neck portion 14 in the circumferential direction is entirely covered with the first covering portion 18. . The first covering portion 18 can prevent biting of the head portion 13 and the neck portion 14, and it is more preferable if the covering range is 80% or more.

In this embodiment, for example, about 60% or more of the total surface area of the neck portion 14 is covered with the first covering portion 18 . The first covering portion 18 can prevent the head portion 13 and the neck portion 14 from being bitten. Further, it is more preferable that the range covered by the first covering portion 18 is 60% or more and 90% or less.

The second covering portion 17 and the first covering portion 18 are continuous through a notch portion 31 provided in the plate fitting base portion 15 and integrally formed to constitute the covering portion 12 . The thickness of the covering part 12 is set to the minimum thickness so that the user can feel the softness when biting and is not easily scratched. The thickness of the covering portion 12 is preferably 0.7 mm or more and 1.1 mm or less, more preferably 0.8 mm or more and 0.9 mm or less. By setting the thickness of the covering portion 12 to 0.7 mm or more, the effect of the covering can be obtained. Further, by increasing the amount of resin to be filled in the manufacturing stage, short shots are less likely to occur, and chipping of a part of the molded product can be prevented. Further, by setting the thickness of the covering portion 12 to 1.1 mm or less, the strength of the neck portion 14 in particular can be sufficiently secured. Therefore, the thickness of the covering portion 12 is preferably set within the above range.

Moreover, as shown in FIG. 8, it is preferable that at least the height difference between the surfaces 11A and 12A at the boundary portion between the covering portion 12 and the main body portion 11 is small. Therefore, by setting the height of the step portion 11F of the main body portion 11 according to the thickness of the covering portion 12, the first surface 11A and the surface 12A of the covering portion 12 can be made flush with each other. .

Further, it is preferable that the corner portion 11c of the stepped portion 11F on the first surface 11A side is rounded with a radius of 0.2 mm to 0.5 mm with the center O1 inside the main body portion 11. As shown in FIG. A corner portion 11d on the second surface 11B side of the stepped portion 11F is preferably rounded with a radius of 0.2 mm to 0.5 mm with the center O2 on the outside of the body portion 11. FIG.

Thus, when the radius of each corner 11c, 11d at the boundary is 0.2 mm or more, the stress is easily dispersed even in the portion where the volume of the hard resin changes greatly, and the strength is improved. Also, if the radius of each of the corners 11c and 11d is 0.5 mm or less, it is possible to suppress the occurrence of burrs during molding.

Further, as shown in FIGS. 2 and 3, a finger rest portion 32 made of a soft resin may be provided on a part of the front surface of the handle portion 16 . The finger rest portion 32 is located near the neck portion 14 of the handle portion 16, and this portion connects (penetrates) the second covering portion 17 on the back side and the toothbrush main body 10. However, it does not have to be within the range of the thickness of the soft resin. An arbitrary design, character, or the like may be given to the finger rest portion 32 . Note that the finger rest portion 32 may have a certain degree of thickness in order to make the design and letters stand out.

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

The boundary between the stress relief portion 34 and the first covering portion 18 is recessed toward the handle portion 16 side and has a gentle U shape that opens toward the head portion 13 side. The U-shaped depth T of the stress relaxation portion 34 is preferably in the range of 0.8 mm or more and 1.6 mm or less, and more preferably in the range of 1.0 mm or more and 1.4 mm or less. By setting the U-shaped depth T within the range of 0.8 mm or more and 1.6 mm or less, the bending behavior of the first covering portion 18 made of a soft resin material changes rapidly between the neck portion 14 and the plate fitting base. Concentrated stress can be relieved and sufficient strength can be ensured for the boundary portion of the portion 15 .

The U-shaped stress relief portion 34 preferably has a radius R of 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 stress dispersing effect is weakened, so it is preferable to set the angle within the above range.

In this embodiment, the stress relief portion 34 is formed only on the front side of the neck portion 14, for example. As a result, stress can be relieved at the boundary between the neck portion 14 and the plate fitting base portion 15 on the front side, where stress is likely to concentrate and warp during use.

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

As shown in FIG. 5, of the boundary between the first covering portion 18 and the exposed portion 33, excluding the notch portion 31, the position of the boundary line J at the position closest to the handle portion 16 is the plate fitting position. It is preferably positioned closer to the head portion 13 than the starting position of the base portion 15 . The starting position of the plate fitting base portion 15 in this embodiment is the position of the surface 15b of the insertion portion 15B when the toothbrush 1 is viewed from the front side.

The position of the boundary line is preferably 1 mm or more away from the starting position of the plate fitting base portion 15 . By shifting the position of the boundary line J with the exposed portion 33 made of a hard resin material from the starting position of the plate fitting base portion 15 where the bending behavior of the first covering portion 18 made of a soft resin material changes abruptly, Stress during brushing can be relaxed.

<Method for manufacturing toothbrush 1>
The toothbrush 1 of this embodiment is produced by two-color molding using different materials on the primary side and the secondary side.
First, the main body 11, which serves as a base, is produced by injection molding using a hard resin material.
Next, the cover portion 12 is produced by flowing a soft resin material from the handle portion 16 side of the main body portion 11, which is a primary molded product, into the mold.

At this time, the soft resin material that has flowed in covers a predetermined region of the surface of the handle portion 16, and then covers the neck portion 14 through the notch portion 31 provided on the back side of the plate fitting base portion 15, followed by flocking. By covering the surface of the head portion 13 excluding the surface 19 , the covering portion 12 is produced on the surface of the main body portion 11 . Thus, the toothbrush 1 of this embodiment is produced.

In the present embodiment, the covering portion 12 is formed so as to cover the surface of the head portion 13 excluding the flocked surface 19, but is not limited to this, and covers the surface of the head portion 13 including the flocked surface 19. A covering portion 12 may be formed.

Further, in the present embodiment, only one notch portion 31 is provided, but a plurality of notch portions 31 may be provided.

The toothbrush 1 for infants needs to be configured so as not to poke the throat during use. Therefore, although the toothbrush 1 for infants has the throat-strike prevention plate 20 mounted at a predetermined position on the toothbrush body 10, the length of the neck portion 14 is shorter than that of the toothbrush for adults. Stress tends to concentrate at the base of the neck portion 14 .

In addition, in a normal toothbrush without the throat poke prevention plate 20, the stress is dispersed by bending the whole toothbrush. In the structure of 1, that portion is strong, and the load during brushing tends to concentrate on the boundary portion between the plate fitting base portion 15 and the neck portion 14 adjacent to it.
Therefore, securing the strength of this portion is a problem. This is a particularly important issue for infants who may chew on the toothbrush during use.

For this reason, the toothbrush 1 of the present embodiment is devised to relieve the stress during brushing.

First, the toothbrush 1 of the present embodiment is configured such that the covering portion 12, which is generally provided only on the handle portion 16, is also provided on the neck portion 14 and the head portion 13 as well. In other words, by covering the surfaces of the head portion 13 and the neck portion 14, which are likely to be bitten by infants during use, with the covering portion 12, bite marks can be prevented. Thereby, it can be used without damaging the oral cavity. In addition, good hygiene can be maintained. However, by having the covering structure, the volume of the hard resin material is reduced, and it is further necessary to ensure the strength described above.

Therefore, in the present embodiment, the notch portion 31 is provided in the plate fitting base portion 15 of the body portion 11 in consideration of the fact that the length of the neck portion 14 is short because the toothbrush 1 is for infants. Thereby, the second covering portion 17 covering the handle portion 16 and the first covering portion 18 covering the head portion 13 and the neck portion 14 can be formed into a continuous and integrated structure.

As a result, the boundaries between the covering portions 17 and 18 made of the soft resin material and the main body portion 11 made of the hard resin material do not close around the axis of the main body portion 11, so that the second covering portion 17 and the first covering portion 17 are not closed. Stress concentration at the boundary position can be alleviated more than the configuration in which the covering portion 18 is separated.

That is, by continuously forming the second covering portion 17 and the first covering portion 18 through the notch portion 31, the stress during brushing can be easily dispersed in the longitudinal direction of the toothbrush 1. Therefore, it is preferable to provide the notch 31 on the back side of the toothbrush 1 to which stress is likely to be applied during brushing.

Further, by providing the notch portion 31, a step is not formed in the covering portion 18, and the tensile stress applied to the covering portion 17 can be dispersed.

Further, by providing the U-shaped stress relief portion 34 in the exposed portion 33 of the neck portion 14 , the boundary with the first covering portion 18 is formed in a U-shape, and along the axis of the neck portion 14 , The stress during brushing is more likely to disperse in the long axis direction and high strength can be obtained, as compared with a configuration in which a boundary is formed in a circumferential shape. In addition, if the U-shaped depth of the stress relaxation portion 34 is set to a dimension shallower than the above range, the effect of relieving stress is difficult to exert, and if it is set to a dimension deeper than the above range, molding of the main body portion 11 is difficult. Therefore, it is preferable to define the dimensions within the above range.

In addition, the stress relief portion 34 provided on the front side of the neck portion 14 faces the rear surface of the base of the neck portion 14, which is most likely to be subjected to load during brushing, so that when an impact or the like is applied, the neck of the main body portion 11 is relieved. Breakage at the portion 14 can be prevented.

Example of the first embodiment

Hereinafter, the first embodiment of the present invention will be specifically described with reference to Examples, but the present invention is not limited by the following description.
For the evaluation, a toothbrush made of polypropylene as a primary material and an olefinic elastomer as a secondary material was used.

[Intraoral operability]
As testers, five infants (and their guardians) conducted a brushing test, and evaluated ease of operation in the oral cavity according to the following criteria.
≪Evaluation Criteria≫
5: Good 4: Somewhat good 3: Neither 2: Somewhat bad 1: Bad

[Neck Strength]
With the flocked surface 19 facing horizontally and upward, the handle portion 16 of the toothbrush was clamped and fixed. A wire connected to a weight of 2 kg was hung on the flocked surface 19 and allowed to fall freely, and the maximum load (N) on the flocked surface 19 when the neck portion 14 was broken was measured (n=5). The average value of these measured values was classified according to the following evaluation criteria, and the strength of the head portion 13 was evaluated.
≪Evaluation Criteria≫
5: 100 N or more 4: 80 N or more and less than 100 N 3: 60 N or more and less than 80 N 2: 40 N or more and less than 60 N 1: Less than 40 N

[Protection of the oral cavity (resistance to scratching)]
The degree of scratches on five samples after use was visually evaluated, and the average score of five expert panels was calculated for each sample according to the following criteria.
≪Evaluation Criteria≫
5: No scratches at all 4: The surface of the first coating (elastomer) has a dent in one place 3: The surface of the first coating (elastomer) has multiple dents 2: The first One crack on the surface of the coating (elastomer) 1: Multiple cracks on the surface of the first coating (elastomer)

Table 1 shows the specifications and evaluation results of the toothbrushes of Examples 1-10, and Table 2 shows the specifications and evaluation results of the toothbrushes of Examples 11-14.

As shown in Table 1, the toothbrushes of Examples 1 to 14 have good intraoral operability, are less likely to be bitten, sufficiently protect the oral cavity, and have sufficient strength of the neck portion 14 and the handle portion 16. Secured. Among these, in particular, the toothbrushes of Examples 1 to 10 were able to obtain each of the above effects on average.

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

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

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

In the toothbrush of Example 4, the proportion of the elastomer resin in the structure of the neck portion 14 of the elastomer resin and the polypropylene is slightly smaller than that of the structure of Example 1. Since the thickness of the neck portion 14 is the same as in Example 1, the percentage of polypropylene in the neck portion 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 was higher than that of Example 1, it was possible to sufficiently secure the protection of the oral cavity.

In the toothbrush of 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 recess of the stress relief portion 34 of the exposed portion 33 of the neck portion 14 reaches the surface 15b of the insertion portion 15B of the plate fitting base portion 15, and the neck portion 14 There is a first covering 18 along the entire length of the . Even with such a configuration, an effect close to that of the first embodiment could be obtained. From the standpoint of strength of the neck portion 14 and the handle portion 16, it is desirable that the position of the boundary be located closer to the head portion 13 than the plate fitting base portion 15 in the entire circumferential direction of the neck portion 14. I found out.

The toothbrush of Example 7 is configured without the stress relaxation portion 34 . Even with such a configuration, an effect close to that of the first embodiment could be obtained. From the standpoint of strength of the neck portion 14 and the handle portion 16, it has been found that it is desirable to have the stress relief portion 34. FIG.

The toothbrush of Example 8 has a configuration in which the groove depth of the stress relief portion 34 is shallow. Even with such a configuration, an effect close to that of the first embodiment could be obtained. From the standpoint of the strength of the neck portion 14 and the handle portion 16, it was found that the groove depth of the stress relief portion 34 should preferably be 0.8 mm or more.

The toothbrush of Example 9 has a configuration in which the groove depth of the stress relaxation portion 34 is deep. Even with such a configuration, an effect close to that of the first embodiment could be obtained. From the standpoint of the strength of the neck portion 14 and the handle portion 16, it was found that the groove depth of the stress relief portion 34 should preferably be 1.6 mm or less.

The toothbrush of Example 10 has a configuration in which the stress relaxation portions 34 are provided on both side surfaces of the neck portion 14 instead of on the flocked surface 19 side. Even with such a configuration, an effect close to that of the first embodiment could be obtained. It has been found that it is desirable to position the stress relief portion 34 on the flocking surface 19 side of the neck portion 14 in terms of the strength of the neck portion 14 and the handle portion 16 .

Although the toothbrush of Example 11 was not provided with the notch portion 31 in the plate-fitting base portion 15, the operability in the oral cavity was good and a sufficient protective effect in the oral cavity was obtained.

Since the toothbrush of Example 12 has a thin neck portion 14, the operability in the oral cavity is very good.

Since the toothbrush of Example 13 contains a large proportion of the elastomer resin forming the neck portion 14, it is highly effective in protecting the oral cavity.

The toothbrush of Example 14 has a high strength structure from the neck portion 14 to the handle portion 16 because the proportion of polypropylene constituting the neck portion 14 is large.

As described above, in the toothbrush of the first embodiment, the thinner the neck portion 14, the better the operability in the oral cavity, and the thicker the thickness of the first covering portion 18, the more the oral cavity can be sufficiently protected. can. Regarding the strength of the neck portion 14, not only the thickness of the neck portion 14 (thickness of polypropylene), but also the presence or absence of the notch portion 31 in the plate fitting base portion 15, the first covering portion 18 in the neck portion 14 and the exposed portion. The position of the boundary with the portion 33 (the position of the boundary between the elastomer resin and polypropylene), the position of the stress relaxation portion 34, etc. also contribute.

[Second embodiment]
FIG. 9A is a front view showing the configuration of the toothbrush of the second embodiment. FIG. 9B is a rear view showing the configuration of the toothbrush of the second embodiment. FIG. 10A is a front view showing the configuration of the toothbrush body of the second embodiment. FIG. 10B is a rear view showing the configuration of the toothbrush body of the second embodiment. FIG. 11 is a partially enlarged view showing the configuration around the neck portion of the toothbrush body of the second embodiment. FIG. 12 is a partially enlarged view showing the configuration around the neck portion of the toothbrush body of the second embodiment.

As shown in FIGS. 9A and 9B, the toothbrush 40 of the second embodiment is configured assuming a toothbrush used by a child up to about 8 months old, for example. The toothbrush 40 includes a toothbrush main body 40A and a second throat-strike prevention plate 40B detachably attached to the toothbrush main body 40A.

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

40 A of toothbrush main bodies are comprised by the main-body part 41 which consists of hard resin materials, and the coating part 42 which covers the surface of at least one part of main-body part 41 and which consists of soft resin materials.
The main body portion 41 can be produced by injection molding, for example, using a hard resin material similar to that of the previous embodiment.

The covering portion 42 has a first covering portion 48 that covers at least a portion of the surface of the neck portion 44 and a second covering portion 47 that covers at least a portion of or the entire surface of the handle portion 46 . As the soft resin material of the covering portion 12, the same material as in the first embodiment can be used.

Since the throat-strike prevention plate 40B has the same configuration as that of the first embodiment, the description thereof is omitted.

(Toothbrush body)
In this embodiment, since the target users of the toothbrush 40 are infants, the overall length of the toothbrush main body 40A in the longitudinal direction is determined in consideration of operability for infants. For example, about 70 mm to 110 mm is preferable, and about 80 mm to 100 mm is more preferable.

As shown in FIGS. 11 and 12, the head portion 43 is located on the tip side of the body portion 41 and has flocked surfaces 49A and 49B on both sides in the thickness direction. A plurality of bristles 43a made of a soft resin material are provided on each of the bristles 49A and 49B.

The material of the bristles 43a is not particularly limited, and examples include polyamides such as 6-12 nylon and 6-10 nylon, PET, PBT, polytrimethylene terephthalate (PTT), PEN, polybutylene naphthalate (PBN), and the like. Synthetic resin materials such as polyester, polyolefin such as PP, olefin elastomer, styrene elastomer, and silicone can be used. These resin materials may be used singly or in combination of two or more. Since infants up to about 8 months old may chew on the toothbrush during use, elastomer and silicone are preferable as the material of the bristles.

The neck portion 44 is a portion extending from one end side of the head portion 43 . Specifically, from the end point of the curve forming the corner cut from the neck portion 44 in the plan view shape of the head portion 43, that is, from the position of the boundary P1 where the bending direction of the curve forming the corner cut changes, the insertion portion It is length L3 to the surface 45b of 45B.

The neck portion 44 has a circular or elliptical cross-sectional shape, and its width is constant or widens along its length. The length of the neck portion 44 is determined in consideration of the intraoral size of the infant. 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.

Also, the range of width and thickness dimensions (including the minimum diameter) of the thinnest portion of the neck portion 44 and the range of width and thickness dimensions (including the maximum diameter) of the thickest portion of the neck portion 44 are the same as in the first embodiment. The width and thickness dimensions of the neck portion 44 described above are dimensions including the thickness of the first covering portion 48 .

As shown in FIGS. 10A and 10B, the handle portion 46 of the present embodiment has 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 head portion 43 side). . As in the first embodiment, 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 side of the head portion 43 to the base portion 45a of the plate fitting base portion 45. The length L5 of the handle portion 46 shown in 10B is preferably, for example, approximately 60 mm to 70 mm.

Alternatively, since the handle portion 46 is ring-shaped, the outer diameter D1 and the inner diameter D2 may be defined respectively. The difference between the outer diameter D1 and the inner diameter D2 of the handle portion 46 corresponds to the dimension of the width W of the handle portion 46 when viewed from the front, and is set to a dimension that is easy for an infant to grasp. Further, as shown in FIG. 12, the width W1 of the handle portion 46 in a side view is wider than the width W2 of the neck portion 44. As shown in FIG.

As shown in FIGS. 11 and 12, the plate fitting base portion 45 is provided between the neck portion 44 and the handle portion 46 and is formed in an annular shape around the central axis O of the toothbrush body 40A. The plate fitting base portion 45 includes a plate fitting portion 45A, an insertion portion 45B located on the head portion 43 side of the plate fitting portion 45A, and a reinforcing portion 45C located on the handle portion 46 side of the plate fitting portion 45A. , and is formed to extend concentrically in a direction perpendicular to the central axis O from the neck portion 44 and the handle portion 46 .

The plate fitting portion 45A, the insertion portion 45B, and the reinforcing portion 45C have different diameters, with the plate fitting portion 45A having the largest diameter. The insertion portion 45B and the reinforcement portion 45C may have the same diameter or may have different diameters. Since the insertion portion 45B is a portion into which the throat attachment prevention plate 20 is fitted, it is necessary to match the diameter of the through hole 21, but the plate fitting base portion 45 is provided to ensure the strength of the neck portion 44. Since it is a part, there is no specific diameter regulation.

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

In the plate fitting base portion 45 of the present embodiment, the above-described inserts are provided on the front surface (the surface on the side of the flocking surface 49A) shown in FIG. 10A and the back surface (the surface on the side of the flocking surface 49B) shown in FIG. Notch portions 31, 31 are provided axially through the portion 45B, the plate fitting portion 45A, and the base portion 4C.

As in the first embodiment, the cutout depth of the notch portions 31 is preferably such that the plate fitting base portion 45 does not have a convex shape. Also in the present embodiment, the bottom surfaces of the notches 31 and 31 connect the surfaces of the handle portion 46 and the neck portion 44 smoothly so that the surfaces of the handle portion 46 and the neck portion 44 are connected smoothly. They are flush with each other.

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

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

The first covering portion 48 covers the entire circumferential direction of at least a portion of the neck portion 44 . In this embodiment, the front end side of the neck portion 44 on the side of the head portion 43 is covered with the first covering portion 48 all around the center axis O. As shown in FIG. In this embodiment, for example, when the total length of the neck portion 44 in the length direction is 100%, at least 40% or more of the area of the neck portion 44 in the circumferential direction is entirely covered with the first covering portion 48. there is The first covering portion 48 can prevent the head portion 43 and the neck portion 44 from being bitten, and it is more preferable if the covering range is 50% or more.

The first covering portion 48 covers substantially the entirety of the head portion 43 including the flocked surfaces 49A and 49B and part of the regions within the notches 31 provided on the front and back of the neck portion 44. It's set up.

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

The second coating portion 47 and the first coating portion 48 are continuous through a pair of notch portions 31, 31 provided in the plate fitting base portion 45, and are integrally configured to form the coating of the present embodiment. A part 42 is constructed. The thickness of the covering part 42 is set to the minimum thickness that allows the user to feel softness when chewing and is hard to be scratched. The thickness of the covering portion 12 is the same as in the first embodiment.

In the present embodiment, as shown in FIGS. 11 and 12, a portion of the neck portion 14 on the side of the plate fitting base portion 45, and a portion of the surfaces inside the notches 31, 31 of the plate fitting base portion 45 , and a portion of the handle portion 46 on the side of the plate fitting base portion 45 is an exposed portion 53 that is not covered along with the first covering portion 48 and the second covering portion 47 . The surface of the plate fitting base portion 45 is not covered with either the first covering portion 48 or the second covering portion 47 .

The exposed portion 53 has a pair of stress relief portions 54 , 54 on the boundary side with the first covering portion 48 . The pair of stress relieving portions 54, 54 are provided on both side surfaces of the toothbrush 40, respectively, and are positioned axially displaced from the positions of the notch portions 31, 31. As shown in FIG.

As shown in FIGS. 11 and 12, the boundaries between the stress relaxation portions 54, 54 and the first covering portion 48 are formed through the notches 31, 31 when viewed from the front and back of the toothbrush main body 40A, respectively. Each of them extends toward the handle portion 46 and has a Y shape that protrudes toward the head portion 43 .

As shown in FIG. 11, the Y-shape of the stress relaxation portion 54 has a radius R1 of, for example, about 0.5 mm to 3.5 mm at the tip of the stress relaxation portion 54 on the side of the head portion 43 when viewed from the front. Preferably. Also, as shown in FIG. 12, it is preferable that the radius R2 of the tip of the stress relief portion 54 when viewed from the side is, for example, about 1.0 mm to 2.5 mm.
The Y-shape of the stress relaxation portion 54 may be configured by connecting a plurality of curves with different radii.

When the flocked surfaces 49A and 49B are provided on the front and back surfaces of the toothbrush as in the present embodiment, the front and back surfaces can be discriminated by providing the stress relaxation portions 54 and 54 on the front and back surfaces, respectively. Even if an infant who has difficulty in brushing uses either the front or back brush, stress concentration on the neck portion 44 during use can be alleviated.

As shown in FIG. 11 , on the tip side of the Y-shaped stress relief portion 54 , that is, on the forked tip end of the stress relief portion 54 on the side of the head portion 43 , a point M where the forked curve changes to a straight line is the plate fitting point. It is preferably positioned closer to the head portion 43 than the starting position of the base portion 45 . The starting position of the plate fitting base portion 45 is the position of the surface 45b of the insertion portion 45B when the toothbrush 40 is viewed from the front side.

The depth T2 of the Y-shaped bifurcated portion of the stress relieving portion 54 corresponds to the length from the starting point of the stress relieving portion 54 on the head portion 43 side to the point M described above. Y-shaped depth T2 is, for example, preferably in the range of 1.0 mm or more and 3.5 mm or less, and more preferably in the range of 2.0 mm or more and 3.0 mm or less. By setting the Y-shaped depth T2 within the above range, the bending behavior of the first covering portion 48 made of a soft resin material changes sharply at the boundary portion between the neck portion 44 and the plate fitting base portion 45. Concentrated stress can be relieved and sufficient strength can be ensured.

Further, as shown in FIG. 11, the length L4 of the Y-shaped rear end of the stress relief portion 54 is at least 10 mm or more, preferably in the range of 10 mm to 12 mm. The length L5 is the length of the straight portion of the stress relief portion 54 on the side of the handle portion 46, 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 convergence point M of the Y-shaped bifurcated portion of the stress relief portion 54 to the surface 45b of the insertion portion 45B is preferably 1 mm or more. That is, the position of the convergence point M of the Y-shaped bifurcated portion of the stress relaxation portion 54 is preferably separated from the starting position of the plate fitting base portion 45 by 1 mm or more. By shifting the convergence point M of the Y-shaped bifurcated portion of the stress relaxation portion 54 from the starting position of the plate fitting base portion 45 where the bending behavior changes abruptly, the stress during brushing can be relieved.

A width W3 of the starting point of the stress relief portion 54 on the neck portion 44 side shown in FIG.

The toothbrush 1 for infants has a structure in which consideration is given to avoiding throat thrusting during use, and the structure is also friendly to the gums because the oral cavity of infants is smaller than that of infants and all the baby teeth have not yet erupted. There is a need to. It is also important to have a structure that is easy to hold even if the grip force is weak.

Therefore, in this embodiment, the length of the neck portion 44 is made shorter than that of the toothbrush for infants according to the size of the oral cavity of the infant, and the handle is also ring-shaped so that the infant can grasp it by itself from any angle. made it possible. In addition, by providing a brush portion using a soft resin material on each of the front and back surfaces of the head portion 43, even an infant having difficulty distinguishing between the front and back can clean both upper and lower teeth simply by biting the head portion 43. is possible. In addition, since the brush portion is made of a soft resin material, it is gentle on the gums and does not damage the oral cavity.

As described above, the infant toothbrush 1 has the throat-stabbing prevention plate 20 mounted at a predetermined position on the toothbrush main body 40A. , the portion is strong and hard to bend. In addition, since the length of the neck portion 44 is extremely short compared to that of toothbrushes for adults, the stress during brushing tends to concentrate on the base of the neck portion 44 .

Therefore, in the present embodiment, the notch portion 31 and the stress relief portion 54 are provided on both the front and back sides of the neck portion 44 in accordance with the brush portions on the front and back sides of the head portion 43, so that the stress during brushing can be relieved. .

Further, the plate fitting base portion 45 has a three-stage structure, and a reinforcement portion 45C is further provided at the base of the handle portion 46 side, thereby improving the strength around the neck portion.

Example of the second embodiment

EXAMPLES The second embodiment of the present invention will be specifically described below with reference to Examples, but the present invention is not limited by the following description.
For the evaluation, a toothbrush made of polypropylene as a primary material and an olefinic elastomer as a secondary material was used.

[Intraoral operability]
As testers, a brushing test was conducted with five infants, and the easiness of operability in the oral cavity was evaluated according to the following criteria from the viewpoint of guardians.
≪Evaluation Criteria≫
5: Good 4: Somewhat good 3: Neither 2: Somewhat bad 1: Bad

[Neck Strength]
With the bristle-implanted surface 49A facing horizontally and upward, the handle portion 46 of the toothbrush was clamped and fixed. A wire connected to a weight of 2 kg was hung on the flocked surface 49A, the weight was allowed to fall freely, and the maximum load (N) on the flocked surface 49A when the neck portion 44 was broken was measured (n=5). The average value of these measured values was classified according to the following evaluation criteria, and the strength of the head portion 43 was evaluated.
≪Evaluation Criteria≫
5: 100 N or more 4: 80 N or more and less than 100 N 3: 60 N or more and less than 80 N 2: 40 N or more and less than 60 N 1: Less than 40 N

[Protection of the oral cavity (resistance to scratching)]
The degree of scratches on five samples after use was visually evaluated, and the average score of five expert panels was calculated for each sample according to the following criteria.
≪Evaluation Criteria≫
5: No scratches at all 4: The surface of the first coating (elastomer) has a dent in one place 3: The surface of the first coating (elastomer) has multiple dents 2: The first One crack on the surface of the coating (elastomer) 1: Multiple cracks on the surface of the first coating (elastomer)

Table 3 shows the specifications and evaluation results of the toothbrushes of Examples 1 to 9.

As shown in Table 3, the toothbrushes of Examples 1 to 8 have good operability in the oral cavity, are less likely to be bitten, sufficiently protect the oral cavity, and have sufficient strength in the neck portion 44 and the handle portion 46. Secured. Especially among these, the toothbrush of Example 1 was highly evaluated in each item.

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

Using the toothbrush of Example 1 as a reference, the toothbrush of Example 2 gave the same evaluation as in Example 1 with respect to intraoral operability and oral protection. As for the strength of the neck portion 44, it was found that the notch portion 31 is more desirable.

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 is partially aligned, and the stress relaxation portion 54 is not provided. is. Even with such a configuration, the same evaluation as in Example 1 was obtained for intraoral operability and oral protection. As for the strength of the neck portion 44, it was found that the notch portion 31 is more desirable.

The toothbrush of Example 4 is configured without the stress relief portion 54 . Even with such a configuration, the same evaluation as in Example 1 was obtained for intraoral operability and oral protection. Further, it was found that it is desirable to have the stress relief portion 54 for the strength of the neck portion 44 as well.

The toothbrush of Example 5 has a Y-shaped bifurcated portion with a short length of 1.0 mm. Even with such a configuration, the same evaluation as in Example 1 was obtained for intraoral operability and oral protection.
The toothbrush of Example 6 has a Y-shaped bifurcated portion with a long length of 3.9 mm. In the case of this configuration, the same evaluation as in Example 1 was obtained with respect to intraoral operability and oral cavity protection, and a higher evaluation than in Example 1 was obtained with respect to the strength of the neck portion 44 .
From Examples 5 and 6, it was found that in order to increase the strength of the neck portion 44, it is preferable that the length of the Y-shaped bifurcated portion is long.

In the toothbrush of Example 7, compared with the toothbrush of Example 1, the thickness of the neck portion main body made of the primary resin in the neck portion 44 of the neck portion 44 is as thin as 4 mm. high.
In the toothbrush of Example 8, the strength of the neck portion 44 was highly evaluated because the thickness of the neck portion 44 (neck portion main body) was as thick as 7 mm.
From Examples 7 and 8, there is a trade-off relationship between the strength of the neck portion 44 and the intraoral operability and protection of the oral cavity, and it is desirable to set the thickness of the neck portion 44 from the balance between the two. Do you get it.

The toothbrush of Example 9 has a structure in which 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 for the intraoral operability, but the strength of the neck portion 44 and the protection in the oral cavity were considerably lower than in Example 1. For this reason, the strength of the neck portion 44 and protection of the oral cavity are preferably such that the length of the first covering portion 48 is 40% or more of the total length of the neck portion 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. can be protected. Regarding the strength of the neck portion 44, not only the thickness of the neck portion 44 (thickness of polypropylene), but also the presence or absence of the notch portion 31 of the plate fitting base portion 45, the position of the boundary between the elastomer resin and the polypropylene in the neck portion 44. , the position of the stress relief portion 54, the length of the Y-shaped bifurcated portion, and the like also contribute.

Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such examples. It is obvious that a person skilled in the art can conceive of various modifications or modifications within the scope of the technical idea described in the claims, and these are also within the technical scope of the present invention. be understood to belong to

In the above-described first and second embodiments, the toothbrush main body and the throat-strike prevention plate are separate members, and the throat-strike prevention plate is detachably attached to the toothbrush main body. However, the toothbrush main body and the throat-stabbing prevention plate may be integrally configured.

In the first embodiment, the plate fitting base portion 15 of the toothbrush body 10 has a two-stage configuration (plate fitting portion 15A and insertion portion 15B), but only one stage (plate fitting portion 15A or insertion portion 15B) is provided. only), or a configuration with three or more stages as in the second embodiment. In this case, it is preferable to define the diameter, etc., at the base portion with the widest diameter. Also in the second embodiment, the configuration of the plate fitting base portion 45 is not limited to the configuration described above, and may be configured in one or two stages, for example.

Further, the shape of the stress relief portion is not limited to the shape shown in each of the above-described embodiments, and for example, a U-shaped stress relief portion and a Y-shaped stress relief portion may be combined.

DESCRIPTION OF SYMBOLS 1, 40... Toothbrush 10, 40A... Toothbrush main body 11, 41... Main-body part 12, 42... Coating part 13, 43... Head part 14, 44... Neck part 15... Plate fitting base part, 15A ... fitting part 15B... insertion part 15b, 20a... surface 16, 46... handle part 17, 47... second covering part 18, 48... first covering part 19, 49A, 49B... flocking Surface 20...Prevention plate 21...Through hole 23...Plate side fitting receiving part 31...Notch part 33...Exposed part 34, 54...Stress relaxation part

Claims (13)

A toothbrush body and a throat prevention plate provided on the toothbrush body,
The toothbrush body is
a head portion having a flocked surface;
a neck portion extending from the rear end of the head portion;
a handle portion located on the opposite side of the neck portion from the head portion;
a body portion made of a hard resin material having a plate fitting base portion disposed between the neck portion and the handle portion;
a first covering portion made of a soft resin material covering at least a part of the surface of the neck portion ;
A notch portion is provided in a part of the circumferential direction of the plate fitting base portion,
The first covering portion and a second covering portion covering at least a portion of the handle portion through the notch portion are continuous and integrated.
A toothbrush characterized by: The plate fitting base portion is
a fitting portion that fits into the plate-side fitting receiving portion of the throat attachment prevention plate;
an insertion portion inserted into the through hole of the plate-side fitting receiving portion;
The toothbrush according to claim 1 , wherein the notch penetrates through the fitting portion and the insertion portion. 3. The toothbrush according to claim 1, wherein the end of the neck portion on the side of the handle portion has an exposed portion adjacent to the plate fitting base portion that is not covered with the first covering portion. The exposed portion has at least one stress relief portion on the boundary side with the first covering portion,
4. The toothbrush according to claim 3 , wherein a boundary between said stress relief portion and said first covering portion forms a U-shape recessed toward said handle portion. The first covering portion covers the entire circumferential direction of the neck portion in an area of at least 60% or more when the total length of the neck portion in the length direction is taken as 100%.
The toothbrush according to claim 4 . The toothbrush according to claim 4 or 5 , wherein the U-shaped depth of the stress relief portion is in the range of 0.8 mm or more and 1.6 mm or less. The exposed portion has at least one stress relief portion on the boundary side with the first covering portion,
a boundary between the stress relaxation portion and the first covering portion forms a Y shape recessed toward the handle portion;
The first covering portion and the second covering portion covering at least a portion of the handle portion are continuous and integrated with each other through the notch portion.
The toothbrush according to claim 3 . the neck portion has a circular or elliptical cross-sectional shape and a width that is constant or widens along the length;
The first covering portion covers the entire circumferential direction of the neck portion in an area of at least 40% or more when the total length of the neck portion in the length direction is taken as 100%.
The toothbrush according to claim 7 . The Y-shaped depth of the stress relaxation portion is in the range of 1.0 mm or more and 3.5 mm or less.
The toothbrush according to claim 7 or 8 . The toothbrush according to any one of claims 4 to 9 , wherein the stress relaxation portion is provided on the same side as the bristle-implanted surface in the circumferential direction of the neck portion. The toothbrush according to any one of claims 4 to 10 , wherein the starting point of the stress relief portion on the neck portion side is formed to have the same width as the neck portion. The toothbrush according to any one of claims 1 to 11 , wherein the neck portion has a minimum width and thickness of 4.0 mm or more and 7.0 mm or less. The toothbrush according to any one of claims 1 to 12 , wherein the surface of said head portion is covered with said first covering portion.

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