CN111493506B - Toothbrush with tooth brush - Google Patents

Abstract

The application aims to provide a toothbrush capable of inhibiting oral injury of a user. The toothbrush has: a head (14) having a bristle surface (21-1 b) on the distal end side; and a handle (16) which is disposed on the rear end side with respect to the head and which comprises a handle body (31), and the toothbrush comprises: a deformation part (15A) which is arranged between the hair implantation surface and the handle part and is deformed by external force applied to the head part; a hard member (17) which is disposed from the head part over a part of the tip side of the handle part and is formed of a hard resin; and a soft portion (26) which is disposed from the deformation portion toward the rear end side, accommodates at least a part of the hard member therein, and is formed of a soft resin.

Description

Toothbrush with tooth brush

The application is a divisional application of the following patent applications:

application number: 201580046958.7

Filing date: 2015, 8, 27 days

The application name is as follows: toothbrush with tooth brush

Technical Field

The present application relates to toothbrushes, and more particularly, to a toothbrush capable of suppressing damage to a user's oral cavity.

The present application claims priority based on patent application 2014-177334 filed on 1 of 9/2014, the contents of which are incorporated herein by reference.

Background

Conventionally, oral injuries have been caused by falling down when a toothbrush is used (specifically, when the toothbrush is put in the mouth), and in particular, oral injuries have been frequently caused when a user of the toothbrush is an infant who is 1 to 3 years old.

Conventionally, as a toothbrush capable of suppressing breakage of a head and a neck, there is a toothbrush disclosed in patent document 1.

Patent document 1 discloses a toothbrush in which a coating layer made of a soft resin is formed on the surface of a base made of a hard resin, and the coating layer covers 70% or more of the sum of the surface area of the head and the surface area of the neck.

Patent document 1 discloses the following: the overall thickness of the head and neck (the sum of the thickness of the base and the thickness of the coating layer covering the base) is 3 to 5mm, the thickness of the base constituting the head and neck is 2 to 4mm, and the thickness of the coating layer is 0.5 to 2mm (preferably 0.8 to 1.5 mm).

Patent document 1 discloses the following: with the above configuration, even when an excessive load is applied to the head and neck, the handle body is hardly broken, or even when the head or neck is broken, the broken portion can be prevented from being exposed from the coating layer.

In the toothbrush disclosed in patent document 1 having the above-described structure, the base constituting the distal end portion of the head portion is covered with a soft resin, and therefore, the soft resin functions as a cushioning material when the toothbrush is bitten by hard or when the toothbrush is strongly touched with the distal end of the head portion in the oral cavity.

Therefore, by using the toothbrush disclosed in patent document 1, damage in the oral cavity caused by the tip end portion of the head can be suppressed.

Prior art literature

Patent literature

Patent document 1: japanese patent application laid-open No. 2013-458

However, in the neck portion of the toothbrush disclosed in patent document 1, a coating layer (preferably, 0.8 to 1.5 mm) made of a soft resin having a thickness thinner than that of the base (thickness of 2 to 4 mm) is provided so as to cover the surface of the base constituting the neck portion.

Accordingly, the toothbrush disclosed in patent document 1 has a neck portion having the following structure: the proportion of the hard resin constituting the base is higher than the proportion of the soft resin.

Therefore, in the head of the toothbrush disclosed in patent document 1, for example, when an external force is applied to the extending direction of the toothbrush (specifically, the direction from the rear end toward the tip of the toothbrush), it is difficult to bend so as not to damage the oral cavity of the user and so as to sufficiently release the external force transmitted to the tip of the head (however, bending is easy as compared with the case where the entire toothbrush is made of a hard resin).

Therefore, in a state in which the toothbrush disclosed in patent document 1 is placed in the mouth, there is a concern that the oral cavity of the user is damaged when a strong external force is applied in a direction from the rear end toward the tip end of the toothbrush.

In particular, in the case of infants between 1 and 3 years old when the toothbrush is used, the risk of oral cavity damage increases.

Disclosure of Invention

The present invention has been made in view of the above-described problems, and an object thereof is to provide a toothbrush capable of suppressing damage in the oral cavity of a user.

Means for solving the problems

In order to solve the above problems, a toothbrush according to an aspect of the present invention includes: a head part having a hair-planting surface on a distal end side; and a handle portion disposed on a rear end side with respect to the head portion and including a handle body, wherein the toothbrush includes: a deformation portion which is disposed between the bristle surface and the shank portion and is deformed by an external force applied to the head portion; a hard member which is disposed from the head portion over a part of the distal end side of the handle portion and is formed of a hard resin; and a soft portion disposed from the deformation portion toward the rear end side, the soft portion being formed of a soft resin and accommodating at least a part of the hard member therein.

In addition, the toothbrush according to the aspect of the present invention is characterized by having a second deformation portion which is disposed on the handle portion and is deformed by the external force.

In the toothbrush according to the aspect of the present invention, the handle portion has at least one annular recess having a reduced diameter in an extending direction of the handle portion, and the second deformation portion is disposed at a disposition position of the recess.

In the toothbrush according to the aspect of the present invention, the hard member includes a first exposed portion exposed on the head portion toward the bristle surface and a second exposed portion exposed on the opposite side of the bristle surface.

In the toothbrush according to the aspect of the present invention, the hard member includes a columnar first protruding portion protruding toward the bristle surface side at the handle portion and exposed, and a columnar second protruding portion protruding toward the opposite side of the bristle surface at the handle portion and exposed.

In the toothbrush according to the aspect of the present invention, the first protruding portion is exposed through a first opening formed in the soft portion on the bristle surface side, and the second protruding portion is exposed through a second opening formed in the soft portion on the opposite side of the bristle surface side.

In the toothbrush according to the aspect of the present invention, the soft portion of the handle portion has a tapered tip portion that tapers toward the tip end side, and the first opening and the second opening are formed in the tapered tip portion.

In the toothbrush according to the aspect of the present invention, the soft portion has a parting line on a surface thereof, the first protruding portion is exposed to one side in a direction orthogonal to the bristle surface through the parting line, and the second protruding portion is exposed to the other side in the orthogonal direction through the parting line.

In the toothbrush according to the aspect of the present invention, the hard member is disposed so as to extend to the handle, and the distal end surfaces of the first and second protruding portions are flush with the outer surface of the handle.

In the toothbrush according to the aspect of the present invention, a portion of the hard member disposed on the rear end side of the handle with respect to the first protruding portion and the second protruding portion has a shape in which a diameter becomes smaller toward the rear end side of the handle.

In the toothbrush according to the aspect of the present invention, at least a distal end portion of the head portion is made of a first soft resin softer than the hard resin, the handle portion main body is made of a second soft resin softer than the hard resin, and the soft portion is made of the second soft resin.

In the toothbrush according to the aspect of the present invention, a first width of the hard member between the bristle surface and the handle in a first direction is larger than a second width of the hard member in a second direction, the first direction being orthogonal to the bristle surface, and the second direction being orthogonal to the longitudinal direction of the handle and the first direction.

In the toothbrush according to the aspect of the present invention, the hard member of the head portion includes the bristle surface and a base member having a plurality of bristle holes, and the first soft resin is disposed so as to cover a part of the base member in a state where the bristle surface and the plurality of bristle holes are exposed.

In the toothbrush according to the aspect of the present invention, a neck portion is disposed between the bristle surface and the handle portion, a width of the neck portion in a second direction is equal to or smaller than a width of the head portion, the second direction is orthogonal to a first direction and a longitudinal direction of the handle portion, and the first direction is orthogonal to the bristle surface.

Effects of the invention

According to the toothbrush of the present invention, oral injury of a user can be suppressed.

Drawings

Fig. 1 is a side view of a toothbrush according to an embodiment of the present invention.

Fig. 2 is a front view of the toothbrush shown in fig. 1.

Fig. 3 is a rear view of the toothbrush shown in fig. 1.

Fig. 4 is an enlarged side view of the hard member shown in fig. 1.

Fig. 5 is an enlarged front view of the hard member shown in fig. 2.

Fig. 6 is an enlarged rear view of the hard member shown in fig. 3.

Fig. 7 is a sectional view of the hard member shown in fig. 4 in the direction of line A-A.

Fig. 8 is a cross-sectional view in the B-B direction of the hard member (specifically, the first portion) shown in fig. 4.

Fig. 9 is a cross-sectional view in the C-C line direction of the hard member (specifically, the second portion) shown in fig. 4.

Fig. 10 is a sectional view in the D-D line direction of the hard member (specifically, the second portion) shown in fig. 4.

Fig. 11 is a cross-sectional view showing a process for manufacturing the toothbrush according to the present embodiment, and is a diagram for explaining a process for forming a hard member using a first mold.

Fig. 12 is a cross-sectional view showing a process for manufacturing the toothbrush according to the present embodiment, and is a diagram for explaining a process for forming the first soft resin, the soft portion, and the handle body using the second mold.

Fig. 13 is a side view showing a modification of the toothbrush according to the embodiment of the present invention.

Fig. 14 is a front view of the toothbrush shown in fig. 13.

Detailed Description

Hereinafter, embodiments to which the present invention is applied will be described in detail with reference to the drawings. The drawings used in the following description are for explaining the structure of the embodiment of the present invention, and the size, thickness, dimension, and the like of each illustrated portion are different from the dimensional relationship of an actual toothbrush.

(embodiment)

Fig. 1 is a side view of a toothbrush according to an embodiment of the present invention. Fig. 2 is a front view of the toothbrush shown in fig. 1. In fig. 2, for convenience of explanation, the illustration of the bristle part 12 composed of a plurality of tufts 12-1 shown in fig. 1 is omitted. Fig. 3 is a rear view of the toothbrush shown in fig. 1.

Fig. 4 is an enlarged side view of the hard member shown in fig. 1. Fig. 5 is an enlarged front view of the hard member shown in fig. 2. Fig. 6 is an enlarged rear view of the hard member shown in fig. 3.

In the structures shown in fig. 1 to 6, the same reference numerals are given to the same structural parts. The X direction shown in fig. 1 to 6 indicates the extending direction of the handle 11 (the extending direction of the neck 15) in a state where the toothbrush 10 is not used.

The Y direction shown in fig. 2, 3, 5 and 6 represents the width direction of the toothbrush 10 (in other words, the second direction orthogonal to the Z direction and the X direction).

The Z direction shown in fig. 1 and 4 shows a first direction perpendicular to the bristle surface 21-1b in a state in which the toothbrush 10 is not used.

In fig. 4 to 6, for convenience of explanation, the symbols of the structural elements of the toothbrush 10 other than the structural elements of the hard member 17 are also shown.

Referring to fig. 1 to 6, a toothbrush 10 of the present embodiment includes a handle 11 and a bristle part 12.

The handle 11 includes a head 14, a neck 15, a handle 16, a head 14, a neck 15, and a hard member 17 forming a part of the handle 16.

In this embodiment, the following toothbrush 10 will be described: a neck 15 having a smaller width in the second direction (Y direction) than the width of the head 14 (maximum width in the Y direction) is disposed between the bristle surface 21-1b and the shank 16.

The head 14 includes a base member 21 made of a hard resin and a first soft resin 22 covering a part of the base member 21. The base member 21 is a part of the structural elements of the hard member 17 made of hard resin, and includes a base member main body 21-1 and two support portions 21-2.

The base member main body 21-1 is formed in a shape that reduces the outer shape of the head 14 by about 1 to 2mm so that the first soft resin 22 can be disposed on the side surfaces and the bottom surface 21-1a of the base member main body 21-1. The base member main body 21-1 has a distal end portion 21-1A, a bottom surface 21-1A, a bristle surface 21-1B, and a bristle hole 21-1B.

The distal end portion 21-1A is a portion located on the opposite side of the base member main body 21-1 from the side where the head 14 and the neck 15 are connected. The distal end portion 21-1A is a portion that faces the inside of the user's mouth when the user brushes his or her teeth with the toothbrush 10. The shape of the distal end portion 21-1a may be, for example, a shape with an arc (arc shape).

Fig. 7 is a sectional view of the hard member shown in fig. 4 in the direction of line A-A. In fig. 7, the same components as those of the structures shown in fig. 1 to 6 are given the same reference numerals. In fig. 7, for convenience of explanation, the symbols of the structural elements of the toothbrush 10 other than the structural elements of the hard member 17 are also shown.

Referring to fig. 1, 3, 4, 6 and 7, the bottom surface 21-1a is a portion covered with the first soft resin 22 and is disposed on the opposite side of the flocked surface 21-1b. The bottom surface 21-1a can be a flat surface, for example.

The bristle surface 21-1b is a flat surface. The bristle surface 21-1B exposes a plurality of bristle holes 21-1B. The flocked surface 21-1b is exposed from the first soft resin 22 as a first exposed portion of the head 14.

In this way, the base member main body 21-1 is made of a hard resin harder than the first soft resin 22, and the plurality of implantation holes 21-1B and the implantation surface 21-1B are exposed from the first soft resin 22, so that the tufts 12-1 constituting the bristle part 12 can be implanted (planted) in the plurality of implantation holes 21-1B by the flat wire type implantation method.

The flocked surface 21-1b is a surface that contacts the inner surface of one of the molds 51-2 (see fig. 12) when the first soft resin 22, the soft portion 26, and the shank main body 31 are resin molded using a second mold 51 shown in fig. 12, which will be described later.

In this way, the bristle surface 21-1B contacts the inner surface of one of the molds 51-2 constituting the second mold 51, and the formation of the first soft resin 22 in the plurality of bristle holes 21-1B and the bristle surface 21-1B can be suppressed.

The base member main body 21-1 constituting one side of the bristle surface 21-1B is provided with a plurality of bristle holes 21-1B. The implantation holes 21-1B are holes for implanting the bristles of the tufts 12-1 constituting the bristle part 12.

As the arrangement of the plurality of implantation holes 21-1B, for example, an arrangement as shown in fig. 2 is used, but the arrangement is not limited thereto, and may be any arrangement pattern such as a so-called checkered arrangement, a zigzag arrangement, or the like.

The number of the plurality of implantation holes 21-1B is not limited to the number of implantation holes 21-1B shown in fig. 2, and may be appropriately set in the range of 10 to 60 holes, for example.

That is, the arrangement of the plurality of implantation holes 21-1B and the number of implantation holes 21-1B can be appropriately set according to the purpose.

The shape of the implantation hole 21-1B is not particularly limited, and for example, circular shapes such as a perfect circle and an ellipse, and polygonal shapes such as a triangle and a quadrangle are used.

The diameter of the implantation hole 21-1B can be determined according to the thickness of the tuft 12-1, and specifically, can be appropriately set in a range of 1 to 3mm, for example.

In the case where the thickness of the head portion 14 in the Z direction is 5.0mm, the thickness of the base member main body 21-1 in the Z direction (in other words, the thickness between the bottom surface 21-1a and the bristle surface 21-1 b) can be, for example, 4.2mm. In this case, the depth of the plurality of implantation holes 21-1B with respect to the implantation surface 21-1B may be, for example, 2.5mm. An example of the thickness of the head 14 is a thickness measured at the center portion of the head 14 in the X direction.

The two support portions 21-2 are provided so as to protrude in the Z direction (downward in the case of the state shown in fig. 1) from the bottom surface 21-1a of the base member main body 21-1. One of the two support portions 21-2 is disposed on the distal end side of the base member main body 21-1, and the other is disposed on the rear end side of the base member main body 21-1. The two support portions 21-2 are arranged to oppose each other in the X direction. The two support portions 21-2 each have a protruding surface 21-2a formed as a flat surface.

The two protruding surfaces 21-2a are exposed from the outer surface of the first soft resin 22 and flush with the outer surface of the first soft resin 22. That is, the support portion 21-2 is exposed on the opposite side of the bristle surface 21-1b as shown in fig. 3 as a second exposed portion of the head 14.

The protruding surface 21-2a is a portion that contacts the inner surface of the first mold 41 (see fig. 11) when the hard member 17 including the base member main body 21-1 is molded using the first mold 41 shown in fig. 11, which will be described later.

Thus, the protruding surface 21-2a contacts the inner surface of the first mold 41 (see fig. 11), and the first soft resin 22 can be formed around the two support portions 21-2 and on the bottom surface 21-1 a.

That is, the protruding amount of the two support portions 21-2 (in other words, the distance from the protruding surface 21-2a when the bottom surface 21-1a is the reference) is equal to the thickness of the first soft resin 22 disposed on the bottom surface 21-1a in the Z direction.

Therefore, the protruding amounts of the two support portions 21-2 can be appropriately set according to the thickness of the first soft resin 22 disposed on the bottom surface 21-1 a. When the thickness of the head portion 14 in the Z direction is 5.0mm and the thickness of the base member main body 21-1 in the Z direction is 4.2mm, the protruding amount of the two support portions 21-2 can be, for example, 0.8mm. An example of the thickness of the head 14 and the base member main body 21-1 is a thickness measured at the center portion of the head 14 in the X direction.

In fig. 1 and 3, the case where there are two support portions 21-2 is described as an example, but the number of support portions 21-2 is not limited to two.

The rear end of the base member 21 having the above-described structure is integrally formed with the tip end portion of the core portion 25 (one end of the core portion 25).

As the hard resin constituting the base member 21, a resin harder than the first soft resin 22 is used. Specifically, as the hard resin constituting the base member main body 21-1, for example, a resin having a flexural modulus of elasticity (JIS K7203) in the range of 500 to 3000MPa can be used.

Specific examples of such hard resins include polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), 1, 4-cyclohexanedimethanol terephthalate (PCT), polyoxymethylene (POM), polystyrene (PS), acrylonitrile-butadiene-styrene resin (ABS), cellulose Propionate (CP), polyarylate, polycarbonate, and acrylonitrile-styrene copolymer resin (AS), but among them, polybutylene terephthalate (PBT) is preferable.

Since polybutylene terephthalate (PBT) has high breaking strength, breakage of the base member 21 or a part of the breakage can be suppressed. The hard resin may be used alone or in combination of two or more kinds.

The first soft resin 22 is provided as follows: the side surfaces and the bottom surface 21-1a of the base member main body 21-1 are covered with the hair-planting surface 21-1B, the plurality of hair-planting holes 21-1B, and the end surfaces 21-2a of the two support portions 21-2 being exposed.

Thus, the first soft resin 22 is disposed so as to cover the distal end portion 21-1A of the base member main body 21-1.

Thus, the first soft resin 22 is disposed so as to cover the distal end portion 21-1A of the base member main body 21-1, and the first soft resin 22 disposed at the distal end portion 21-1A functions as a cushioning material when the user uses the toothbrush 10, so that when an external force is applied in a direction from the rear end side toward the distal end side of the toothbrush 10, the first soft resin 22 disposed at the distal end portion 21-1A strongly presses the inside of the user's mouth, thereby being able to suppress the inside injury of the user's mouth.

The thickness of the first soft resin 22 disposed on the side surface and the bottom surface 21-1a of the base member main body 21-1 can be appropriately set in the range of 0.2 to 2.0mm, for example, 0.8mm, depending on the purpose.

In fig. 1 to 3, the case where the first soft resin 22 is provided so as to cover the side surfaces and the bottom surface 21-1A of the base member main body 21-1 is described as an example, but the first soft resin 22 may be disposed so as to cover at least the distal end portion 21-1A of the base member main body 21-1.

As the first soft resin 22, for example, a soft resin having a hardness of 90 shore a or less in JIS K7215 may be used. Examples of such soft resins include elastomer resins such as polyolefin elastomers, styrene elastomers, and polyester elastomers, but among them, styrene elastomers are preferable from the viewpoint of weldability with polypropylene (PP).

Specific examples of the styrene-based elastomer include SEPTON (trade name) manufactured by kuraray, RIKEN techenos, inc.

The first soft resin 22 may be appropriately selected according to the type of the hard resin constituting the base member 21.

Specifically, when polypropylene (PP) is used as the hard resin constituting the base member 21, the first soft resin 22 is preferably a polyolefin elastomer or a styrene elastomer, and more preferably a styrene elastomer, for example.

By combining the hard resin and the first soft resin 22 constituting the base member 21 as described above, the adhesion between the base member 21 and the first soft resin 22 can be sufficiently ensured.

The length (length in the X direction) of the head 14 having the above-described structure is not particularly limited, and is preferably in the range of 10 to 30mm, more preferably in the range of 12 to 28mm, for example.

When the length of the head 14 is 10mm or more, the area of the hair-planting surface 21-1b in which the hair bundle 12-1 can be planted can be sufficiently ensured. In addition, when the length of the head 14 is 30mm or less, the operability of the toothbrush 10 in the oral cavity can be improved.

The width of the head 14 (the maximum width in the Y direction of the head 14) having the above-described structure is not particularly limited, and is preferably in the range of 7 to 13mm, more preferably in the range of 8 to 12mm, for example.

When the width of the head 14 is 7mm or more, the area of the hair-planting surface 21-1b in which the hair bundle 12-1 can be planted can be sufficiently ensured.

In addition, when the width of the head 14 is 13mm or less, the operability of the toothbrush 10 in the oral cavity can be improved.

Here, referring to fig. 2, the position of the boundary between the rear end of the head 14 and the distal end of the neck 15 and the position of the boundary between the rear end of the neck 15 and the distal end of the handle 16 are defined.

In the present invention, the neck comprises the following parts: between the bristle surface 21-1b and the shank 16, the width in the Y direction is the same as the maximum width of the head 14 or smaller than the maximum width of the head 14.

In the present embodiment, the position where the width in the Y direction is narrowed in the X direction from the tip end of the head 14 toward the tip end of the shank 16, the variation in the width becomes large, and finally the variation in the width in the Y direction is almost eliminated is defined as the position of the boundary between the tip end of the head 14 and the tip end of the neck 15.

The position where the width in the Y direction is narrowed in the X direction from the tip end of the stem portion 16 toward the rear end of the neck portion 15, the variation in the width becomes large, and finally the variation in the width in the Y direction is almost eliminated is defined as the position of the boundary between the rear end of the neck portion 15 and the tip end of the stem portion 16.

In the present invention, the position of the rear end side of the stem portion 16 of the implant hole, which is disposed at a position farthest from the distal end of the head portion 14 in the X direction from the distal end of the head portion 14, may be defined as the position of the boundary between the rear end of the head portion 14 and the distal end of the neck portion 15.

The length of the neck 15 in the X direction can be set appropriately, for example, in the range of 20 to 60mm, and in this case, the total length of the head and the length of the neck can be set appropriately, for example, in the range of 40 to 85 mm.

Neck 15 is the portion connecting head 14 and handle 16. The width of the neck 15 in the Y direction is smaller than the widths of the head 14 and the shank 16. The thickness of the neck 15 in the Z direction can be, for example, the same as the thickness of the head 14.

The neck portion 15 has: a core 25 as a structural element of the hard member 17; a soft portion 26.

The core 25 has: extending in the X direction (extending direction of the neck 15) and penetrating the first portion 25-1 of the neck 15; and a second portion 25-2 extending in the X direction, having one end integrally formed with the first portion 25-1, and disposed on a portion of the handle 16.

Here, the first portion 25-1 constituting the neck 15 will be described, and the second portion 25-2 will be described in describing the structure of the handle 16.

Fig. 8 is a cross-sectional view in the B-B direction of the hard member (specifically, the first portion) shown in fig. 4. In fig. 8, the same components as those shown in fig. 1 to 6 are given the same reference numerals. In fig. 8, for convenience of explanation, the symbols of the structural elements of the toothbrush 10 other than the structural elements of the hard member 17 are also shown. In fig. 8, for convenience of explanation, the symbol of the neck portion 15 is illustrated.

Referring to fig. 1 to 6 and 8, one end of the first portion 25-1 is integrally formed with the rear end of the base member 21, and the other end is integrally formed with the second portion 25-2.

The first portion 25-1 is composed of a hard resin. The first portion 25-1 is composed of a hard resin (a hard resin having a flexural modulus of elasticity (JIS K7203) in the range of 500 to 3000 MPa) that is harder than the second soft resin 27 constituting the first soft resin 22 and the soft portion 26.

The first portions 25-1 are of the same thickness in the X direction. When a strong external force is applied to the distal end of the head 14, the thickness and shape of the first portion 25-1 and the thickness of the soft portion 26 disposed around the first portion 25-1 may be determined such that the neck portion 15 is bent at the deformed portion 15A shown in fig. 2 (for example, near the central portion of the neck portion 15) (in other words, such that the force applied to the distal end of the head 14 is released).

Specifically, when the area of the cross section of the neck portion 15 (the total area of the area S1 of the cross section 25-1a of the first portion 25-1 and the area S2 of the cross section of the soft portion 26) obtained when the central portion of the neck portion 15 in the X direction is cut on the surface orthogonal to the X direction is set to 100%, the area S1 of the cross section 25-1a of the first portion 25-1 is set to 5% or more and less than 50%, preferably, for example, 27%.

As the shape of the first portion 25-1 when cut on the plane orthogonal to the X direction, for example, a circle, an ellipse, a square, a rectangle, a diamond, a star, or the like can be used. In addition, in consideration of safety of the user, the corner of the first portion 25-1 is formed in a shape (arc shape) having an arc.

However, it is preferable that the neck portion 15 is hardly deformed (in other words, the tip of the bristle portion 12 can be stably pressed against the teeth, interdental spaces, etc.) with respect to the Z direction (in other words, the direction of the force applied when pressing the tip of the bristle portion 12 against the teeth, interdental spaces, etc.) when brushing teeth with the toothbrush 10.

Therefore, the first width W1 of the first portion 25-1 in the Z direction (first direction orthogonal to the hair-planting surface 21-1 b) may be larger than the second width W2 of the first portion in the Y direction (second direction) orthogonal to the Z direction. The first width W1 is, for example, 1.5mm to 3.0mm, and the second width W2 is, for example, 1.5mm to 2.0mm.

By making the first width W1 of the first portion 25-1 in the Z direction larger than the second width W2 of the first portion in the Y direction, the deformed portion 15A can be bent in the Y direction when a strong external force is applied to the tip of the head 14 without deteriorating the cleaning performance of the toothbrush 10. Accordingly, the force applied to the distal end of the head 14 can be released, and thus, the oral cavity injury of the user of the toothbrush 10 can be suppressed.

In particular, in the case of an infant who is 1 to 3 years old in the user of the toothbrush 10, the infant may run while the toothbrush 10 is kept in the mouth, but even if the infant falls down in such a case, the oral damage of the infant can be suppressed.

Examples of the cross-sectional shape of the first portion 25-1 having a first width W1 larger than a second width W2 of the first portion 25-1 in the Y direction include an ellipse, a rectangle, and a diamond as shown in fig. 8. In this case, the ellipse includes a long circle in which two semicircles having the same radius are connected by two parallel tangential lines, in addition to a curve formed by a set of points in which the sum of distances from the two focal points is constant.

When the first portion 25-1 having a cross-sectional shape of an ellipse or a diamond is used, the maximum value of the first width W1 may be larger than the maximum value of the second width W2.

In fig. 8, when the diameter R1 of the neck portion 15 is 3.95mm, the first width W1 may be, for example, 1.975mm. At this time, the second width W2 can be, for example, 1.7mm.

The soft portion 26 accommodates the first portion 25-1 therein and is composed of a second soft resin 27 softer than the hard resin constituting the core portion 25. The soft portion 26 is a member for suppressing the exposure of the first portion 25-1, and is also a member for bending the deformed portion 15A of the neck portion 15 when a strong force is applied to the distal end of the head portion 14.

As the second soft resin 27, for example, a soft resin having a shore a hardness of 90 or less in JIS K6253 is used. As such a soft resin, the soft resin exemplified in the description of the first soft resin 22 can be used.

The second soft resin 27 may be composed of a soft resin different from the type of the first soft resin 22 according to the purpose. In this case, for example, the hardness of the soft resin used as the first soft resin 22 may be set higher than the hardness of the soft resin used as the second soft resin 27. By adopting such a structure, the hardness of the distal end of the head 14 can be made different from the hardness of the neck 15.

The same type of soft resin may be used as the first and second soft resins 22 and 27. This can reduce the number of types of soft resins used in manufacturing toothbrush 10.

In fig. 8, the case where the cross-sectional shape of the soft portion 26 is circular is described as an example, but the cross-sectional shape of the soft portion 26 is not limited thereto.

For example, in the case of using the first portion 25-1 having the elliptical cross section 25-1a shown in fig. 8, an elliptical shape having a part of the major axis aligned with the major axis of the cross section 25-1a or the above-mentioned oblong shape may be used as the cross section shape of the soft portion 26. In the case where the cross section 25-1a is elliptical, oblong, or polygonal, the diameter R1 of the neck 15 may be set to a value corresponding to the circumscribed circle of the cross section 25-1 a.

Referring to fig. 1 to 6, the shank 16 includes: a second portion 25-2 (a portion of the core 25) constituting the core 25; a plurality of protruding portions 29 constituting the hard member 17; a handle body 31; annular recesses 32-1, 32-2 (annular recesses); a first rib 34; a second rib 35; and a third rib 37.

Fig. 9 is a cross-sectional view in the C-C line direction of the hard member (specifically, the second portion) shown in fig. 4. Fig. 10 is a sectional view in the D-D line direction of the hard member (specifically, the second portion) shown in fig. 4.

In fig. 9 and 10, the same components as those shown in fig. 1 to 6 are given the same reference numerals. In fig. 9 and 10, the symbol of the handle 16 is illustrated for convenience of explanation. In fig. 9 and 10, for convenience of explanation, reference numerals of the components of the toothbrush 10 other than the components of the handle 16 are also shown.

Referring to fig. 1 to 6, 9 and 10, the second portion 25-2 is made of a hard resin, and one end thereof is integrally formed with the first portion 25-1. The hard resin constituting the second portion 25-2 may be, for example, the same hard resin as the hard resin constituting the first portion 25-1.

The second portion 25-2 is set to the following structure: the cross-sectional shape orthogonal to the X direction is a similar shape that continuously expands in diameter as it goes from one end of the second portion 25-2 to the plurality of columnar protruding portions 29. That is, the second portion 25-2 is configured such that the diameter of the portion where the plurality of protruding portions 29 are provided is maximized.

The portion of the second portion 25-2 disposed on the rear end side of the shank 16 with respect to the plurality of protruding portions 29 is formed as follows: the cross-sectional shape orthogonal to the X direction continuously decreases in diameter from the plurality of protruding portions 29 toward the rear end side of the shank 16.

In this way, since the shape of the portion of the second portion 25-2 that is disposed on the rear end side of the shank 16 with respect to the plurality of protruding portions 29 is set to a shape that becomes smaller in diameter as it goes from the plurality of protruding portions 29 toward the rear end side of the shank 16, for example, when the same soft resin is used as the first and second soft resins 22, 27, as shown in fig. 12 described later, the soft resin is easily moved (flowed) in the direction (X direction) toward the tip end of the head 14 after the hard member 17 is disposed in the second mold 51 and then the soft resin is introduced into the second mold 51 from the rear end side of the second mold 51, so that the entire hard member 17 (excluding the flocked surface 21-1B and the plurality of flocked holes 21-1B) can be surrounded with high accuracy by the soft resin.

As will be described later, when the soft resin is introduced into the second mold 51, the soft resin introduced can suppress the change in the position and orientation of the hard member 17 in the second mold 51.

As shown in fig. 2, the second portion 25-2 is preferably provided in the distal end portion of the shank 16, but is not limited thereto. The second portion 25-2 may also be, for example, internally located within the neck 15.

In the present embodiment, four protruding portions 29 are provided as an example. The four protruding portions 29 are arranged in the circumferential direction of the thickest diameter portion of the second portion 25-2.

The angle formed by the two protruding portions 29 disposed at adjacent positions is, for example, 90 degrees. The space formed between the two protruding portions 29 disposed at adjacent positions functions as a path when introducing the soft resin into the second mold 51 shown in fig. 12 described later. Through this space, the soft resin is supplied to the distal end side of the head 21, and is solidified (cured) to become the first soft resin 22.

The plurality of protruding portions 29 each have a protruding surface 29a. The protruding surfaces 29a of the plurality of protruding portions 29 are exposed from the outer surface of the shank main body 31 (in other words, the outer surface of the shank 16), and are configured to be flush with the outer surface of the shank main body 31 (the outer surface of the shank 16).

As shown in fig. 1, 2 and 10, the protruding portion 29 as the first protruding portion located on the +z side is exposed on the bristle surface 21-1b side through the opening 31a of the shank main body 31 (soft portion 26). The protruding portion 29 as the second protruding portion located on the-Z side is exposed on the opposite side of the bristle surface 21-1b through the opening 31b of the shank main body 31 (soft portion 26). The protruding portion 29 located on the +y side is exposed on the +y side through the opening 31c of the shank main body 31 (soft portion 26). The protruding portion 29 located on the-Y side is exposed on the-Y side through the opening 31d of the shank 16 (soft portion 26). As shown in fig. 1 and 2, the soft portion 26 of the handle 16 has a distal end tapered portion 31A tapered toward the distal end side, and the openings 31A to 31d are formed in the distal end tapered portion 31A. In other words, the protruding portion 29 is exposed to the outside through the openings 31A to 31d formed in the tip tapered portion 31A of the shank 16.

As shown in fig. 10, the cross-sectional shape of the outer surface of the shank 16 is substantially circular, and therefore the cross-sectional shape of the protruding surface 29a is circular arc. Accordingly, the protruding surfaces 29a are exposed to the outside in the radial direction and exposed to the direction perpendicular to the longitudinal direction and the radial direction of the toothbrush 10. Specifically, for example, in fig. 10, the protruding surface 29a of the protruding portion 29 as the first protruding portion located on the +z side is exposed to the +z side, and is exposed to the +y side and the-Y side. Also, for example, in fig. 10, the protruding surface 29a of the protruding portion 29 as the second protruding portion located on the-Z side is exposed to the-Z side, and is exposed to the +y side and the-Y side.

The plurality of protruding portions 29 have the following functions: the second mold 51 (see fig. 12) is used, the hard member 17 is disposed in the space 53 of the second mold 51, and when the handle body 31 is formed, the protruding surface 29a contacts the inner surface of the second mold 51, and the posture of the hard member 17 in the space is maintained together with the two support portions 21-2 constituting the base member 21 (details will be described later). In a state where the hard member 17 is accommodated in the second mold 51, the protruding surfaces 29a of the four protruding portions 29 contact the inner surface of the second mold 51, and the rear end of the hard member 17 is supported from four directions.

The protruding amount of the plurality of protruding portions 29 is equal to the thickness of the second soft resin 27 disposed around the plurality of protruding portions 29. Therefore, the protruding amount of the plurality of protruding portions 29 can be set appropriately so as to be flush with the surface of the second soft resin 27 according to the desired thickness of the second soft resin 27 disposed around the plurality of protruding portions 29.

In fig. 10, when the diameter R2 of the second portion 25-2 is 5.6mm, the protruding amount T1 of the plurality of protruding portions 29 can be set to 1.77mm, for example.

In fig. 1 to 6 and 10, the case where four protruding portions 29 are provided is described as an example of the plurality of protruding portions 29, but the number of the plurality of protruding portions 29 is not limited to four.

For example, the number of the plurality of protruding portions 29 may be three (in this case, the protruding portions 29 disposed at adjacent positions may be disposed so that the angle formed by the protruding portions becomes 120 degrees), or may be two or more and eight or less.

The shape of the plurality of protruding portions 29 may be as follows: the shape of the protruding portion 29 shown in fig. 1 to 6 and 10 is not limited to a cylindrical shape, and has a shape of a flow path through which the soft resin can flow from the rear end side of the plurality of protruding portions 29 to the tip end side of the base member 21. The cross-sectional shape of the columnar plurality of protruding portions 29 may be, for example, a star shape or a heart shape having excellent design.

Referring to fig. 1 to 3, the handle body 31 is a portion gripped by the hand of the user of the toothbrush 10, and is composed of the second soft resin 27.

By forming the handle body 31 from the second soft resin 27 in this way, the handle body 31 can be deformed (specifically, bent) when a strong external force is applied in the direction from the rear end of the toothbrush 10 toward the tip end of the head 14 in a state in which the toothbrush 10 is placed in the mouth.

Accordingly, not only the neck 15 but also the handle body 31 is bent, and external force from the rear end of the toothbrush 10 to the tip of the head 14 can be released in a direction different from this, so that the oral cavity injury of the user of the toothbrush 10 can be suppressed.

Further, by configuring the handle body 31 using the second soft resin 27, even when a strong force is applied to the handle body 31, the handle 16 can be prevented from being damaged (in other words, the handle 16 is broken).

The annular recesses 32-1, 32-2 are annularly provided throughout the entire circumferential direction of the shank main body 31. The annular recess 32-1 is disposed on the rear end side of the shank 16 with respect to the position of the second portion 25-2. The annular recess 32-1 is formed by reducing the diameter of the shank main body 31. That is, in the annular recess 32-1, the cross-sectional shape orthogonal to the X direction is similar to the shank main body 31, and is a shape in which the diameter continuously decreases.

The annular recess 32-2 is disposed at the rear end side of the shank 16 at a distance of, for example, 20mm to 50mm with respect to the position at which the annular recess 32-1 is disposed. The annular recess 32-2 is formed by reducing the diameter of the shank main body 31. That is, in the annular recess 32-2, the cross-sectional shape orthogonal to the X direction is similar to the shank main body 31, and is a shape in which the diameter continuously decreases.

Thus, the annular concave portions 32-1 and 32-2 are formed by reducing the diameter of the handle body 31 in the X direction of the handle body 31, and when a strong external force is applied in the direction from the rear end of the toothbrush 10 to the tip end of the head 14 in a state in which the toothbrush 10 is placed in the mouth, the handle 16 can be easily bent at the position where the annular concave portions 32-1 and 32-2 as the second deformation portions are arranged.

Accordingly, the external force applied in the direction from the rear end of the toothbrush 10 to the distal end of the head 14 can be released more efficiently in a direction different from this, and thus the damage in the oral cavity of the user of the toothbrush 10 can be further suppressed.

Further, the annular recessed portions 32-1, 32-2 are formed by reducing the diameter of the handle body 31 in the X direction of the handle body 31, so that the handle 16 can be easily gripped by a user when using the toothbrush 10, and thus the operability of the toothbrush 10 can be improved.

In fig. 1 to 3, the case where the shank main body 31 is provided with two annular recesses 32-1 and 32-2 is described as an example, but the number of the annular recesses 32-1 and 32-2 is not limited to two. The annular recesses 32-1, 32-2 may be provided in one or more, five or less of the shank main body 31 as needed.

The arrangement position of the annular recesses 32-1, 32-2 is not limited to the arrangement position of the annular recesses 32-1, 32-2 shown in fig. 1 to 3, and may be provided in the handle body 31 located behind the arrangement position of the second portion 25-2.

The first rib 34 is disposed in plural at a portion of the annular recess 32-1 constituting a side surface (in other words, both side surfaces) of the shank main body 31.

The second ribs 35 are disposed in plural at portions of the annular recess 32-2 constituting the side surfaces (in other words, both side surfaces) of the shank main body 31.

The third ribs 37 are disposed in plurality on the side surfaces (in other words, both side surfaces) of the handle body 31 located on the rear end side with respect to the disposition position of the second ribs 35.

The first to third ribs 34, 35, 37 may be made of the second soft resin 27. In this case, the first to third ribs 34, 35, 37 can be formed together at the time of forming the handle body 31.

The first to third ribs 34, 35, 37 are not necessarily required, and may be omitted.

In this way, the plurality of first ribs 34 disposed in the annular recess 32-1, the plurality of annular recesses 32-2 disposed in the annular recess 32-2, and the plurality of third ribs 37 disposed on the side surface of the handle body 31 located on the rear end side of the disposition position of the second ribs 35 are provided, and thus the fingers holding the toothbrush 10 are less likely to slide, and the grip performance of the handle body 31 can be improved.

Referring to fig. 1, the bristle part 12 is composed of tufts 12-1, and the tufts 12-1 are implanted in a plurality of implantation holes 21-1B provided in the base member 21. Tufts 12-1 are used to bundle a plurality of bristles.

The length (hair length) of the hair bundle 12-1 with respect to the hair planting surface 21-1b can be determined by taking into consideration Mao Yingdu and the like required for the hair bundle 12-1. Specifically, the length (hair length) of the hair bundle 12-1 can be appropriately set, for example, in the range of 6 to 13 mm.

The tuft 12-1 may be constituted of, for example, a plurality of bristles having flush lengths, or may be constituted of a plurality of bristles having different lengths.

Fig. 1 illustrates an example of bristle part 12 constituting toothbrush 10, in which the tips of a plurality of tufts 12-1 constituting bristle part 12 are flush, but is not limited thereto.

For example, the step may be provided in the bristle part 12 by making the lengths of the plurality of tufts 12-1 constituting the bristle part 12 different.

The thickness (tuft diameter) of the tufts 12-1 can be determined in consideration of Mao Yingdu and the like required for the tufts 12-1, and can be appropriately set in a range of 1 to 2mm, for example.

All of tufts 12-1 can be the same tuft diameter or can be different from one another.

As the plurality of bristles constituting the tuft 12-1, for example, tapered bristles, which are bristles whose hair tips become sharp as the diameter thereof decreases toward the hair tips, straight bristles, which are bristles having substantially the same diameter from the bristle planting surface 21-1b toward the hair tips, and the like can be used.

As the straight bristles, bristles having bristle tips in a plane substantially parallel to the bristle surface 21-1b and bristles having bristle tips trimmed in a hemispherical shape can be used, for example.

Examples of the material of the bristles constituting the tufts 12-1 include polyamide such as 6-12 nylon (6-12 NY) and 6-10 nylon (6-10 NY), and resin materials such as polyester fibers such as PET, PBT, polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN) and polybutylene naphthalate (PBN), and polyolefin such as PP.

The resin material used as the material of the bristles may be used singly or in combination of two or more kinds.

As the bristles constituting the tufts 12-1, for example, bristles made of polyester having a multi-core structure and having a core portion and at least one sheath portion provided on the outer side of the core portion may be used.

The cross-sectional shape of the bristles constituting the tufts 12-1 is not particularly limited, and for example, circular shapes such as a perfect circle and an ellipse, polygonal shapes, star shapes, clover shapes, four-leaf shapes, and the like can be used.

The cross-sectional shapes of all the bristles constituting the bristle part 12 may be the same or different.

The thickness of the bristles constituting the tufts 12-1 can be determined by considering the material of the bristles. In the case where the cross section of the bristle is circular, the thickness of the bristle can be set to 6 to 9mil, for example. In addition, 1mil is 0.0254mm.

In addition, the tufts 12-1 may be composed of a plurality of bristles having different thicknesses, in consideration of the feeling of use, the feeling of brushing, the cleaning effect, the durability, and the like.

The toothbrush according to the present embodiment includes: a head 14 having a bristle surface 21-1b, at least a distal end portion of which is made of a first soft resin 22; a handle 16 including a handle body 31 made of a second soft resin 27; and a neck 15 connecting the head 14 and the handle 16, the neck 15 having: a core 25 extending in the extending direction (X direction) of the neck 15 and made of a hard resin harder than the first soft resin 22; and a soft portion 26 that is configured by housing the core portion 25 inside and is configured by a second soft resin 27 that is softer than the hard resin, whereby, when a strong external force is applied in a direction from the rear end of the toothbrush 10 toward the tip of the head 14 in a state in which the user puts the toothbrush 10 into the mouth, the neck portion 15 and the handle portion 16 having the second soft resin 27 as the structural elements deform (specifically, bend) so that the force transmitted to the tip of the head 14 can be released, and the softer first soft resin 22 disposed on the tip of the head 14 can be brought into contact with the inside of the mouth of the user, whereby the intraoral injury of the user of the toothbrush 10 can be suppressed.

In particular, in the case of an infant who is 1 to 3 years old in the user of the toothbrush 10, there are cases where the infant runs while keeping the toothbrush 10 in the mouth, but even when the infant falls in such a case, the oral damage of the infant can be suppressed.

In the present embodiment, the case where the hard member 17 having the base member 21, the core 25, and the plurality of protruding portions 29 is used as the constituent elements of the toothbrush 10 has been described as an example, but for example, the toothbrush (hereinafter, for convenience of description, referred to as "toothbrush Q") may be configured using a hard member (hereinafter, for convenience of description, referred to as "hard member P") from which the base member 21 is removed from the constituent elements, and in this case, the same effects as those of the toothbrush 10 of the present embodiment can be obtained.

In this case, the hard member P may be configured as follows: the plurality of protruding portions 29 are provided not only on the rear end side of the core 25 but also on the tip end side of the core 25.

With such a configuration, when the soft resin (the resin of the first and second soft resins 22 and 27) is introduced into the mold (not shown) having a space corresponding to the outer shape of the toothbrush Q, the posture (position) of the hard member P in the mold can be maintained, and thus the toothbrush Q can be manufactured with high accuracy.

In addition, in manufacturing the toothbrush Q (specifically, in implanting the tufts), an in-mold injection method may be used.

Fig. 11 is a cross-sectional view showing a process for manufacturing the toothbrush according to the present embodiment, and is a diagram for explaining a process for forming a hard member using a first mold. Fig. 12 is a cross-sectional view showing a process for manufacturing the toothbrush according to the present embodiment, and is a diagram for explaining a process for forming the first soft resin, the soft portion, and the handle body using the second mold.

In fig. 11 and 12, the same components as those shown in fig. 1 to 10 are given the same reference numerals. The arrow shown in fig. 11 indicates the direction in which the hard resin is introduced, and the arrow shown in fig. 12 indicates the direction in which the soft resin (soft resin N described later) is introduced.

Next, a method for manufacturing the toothbrush 10 according to the present embodiment will be described mainly with reference to fig. 1, 11 and 12.

Here, the following description will be made taking as an example a case where the same kind of soft resin (hereinafter, referred to as "soft resin N" for convenience of description) is used as the first and second soft resins 22, 27.

First, in the step shown in fig. 11, a first mold 41 is prepared, and the first mold 41 is composed of a pair of molds 41-1 and 41-2, and has a space 43 corresponding to the shape of the hard member 17 and an inlet 45 for introducing the hard resin into the space 43.

The mold 41-2 is formed with a protrusion (not shown) for forming the plurality of implantation holes 21-1B. The inlet 45 is disposed on the rear end side of the space 43.

Then, the space 43 is filled with a molten hard resin (resin having a flexural modulus of elasticity (JIS K7203) in the range of 500 to 3000 MPa) as a base material of the hard member 17 through the inlet 45, and the hard resin is cured to form the hard member 17 integrally formed with the base member 21 including the plurality of implantation holes 21-1B and the supporting portion 21-2, the core 25, and the plurality of protruding portions 29. Thereafter, the hard member 17 is removed from the first mold 41.

Next, in the step shown in fig. 12, a second mold 51 is prepared, and the second mold 51 is composed of a pair of molds 51-1, 51-2, and has a space 53 corresponding to the shape of the toothbrush 10 from which the bristle part 12 shown in fig. 1 is removed, and an inlet 55 for introducing a hard resin into the space 53. The joint surfaces of the pair of dies 51-1, 51-2 are set at, for example, the intermediate position in the Z direction of the soft portion 26 (the shank main body 31) shown in fig. 8 to 10.

The mold 51-2 is formed with a protrusion (not shown) for forming the plurality of implantation holes 21-1B. The inlet 55 is disposed on the rear end side of the space 53.

The second mold 51 is provided with protruding portions for forming the annular recesses 32-1, 32-2, the first rib 34, the second rib 35, and the third rib 37 shown in fig. 1.

Next, the hard member 17 is disposed at the distal end portion of the space 53 of the second mold 51. At this time, the inner surface of the die 51-2 is brought into contact with the bristle surface 21-1B, the end surfaces of the two support portions 21-2 are brought into contact with the inner surface of the die 51-1, and the protruding surfaces 29a of the plurality of (four in the present embodiment) protruding portions 29 are brought into contact with the inner surface of the second die 51 so as to cover the plurality of bristle holes 21-1B.

Accordingly, when the soft resin N, which is the first soft resin 22 and the second soft resin 27 (soft resin constituting the soft portion 26 and the handle body 31), is introduced into the space 53 of the second mold 51, the position and posture of the hard member 17 in the second mold 51 can be maintained.

That is, the protruding surface 29a of the protruding portion 29 on the +z side is in contact with the inner surface of the mold 51-2, and the protruding surface 29a of the protruding portion 29 on the-Z side is in contact with the inner surface of the mold 51-1, whereby the hard member 17 is positioned in the Z direction. Further, since both the protruding portion 29 located on the +z side and the protruding surface 29a of the protruding portion 29 located on the-Z side face the +y side and the-Y side, they are positioned in the Y direction by being in contact with the inner surfaces of the molds 51-1 and 51-2.

In addition, the end surfaces of the two support portions 21-2 and the protruding surfaces 29a of the plurality of protruding portions 29 are in contact with the inner surface of the second mold 51, so that a gap for forming the first soft resin 22 and the soft portion 26 can be ensured between the hard member 17 and the second mold 51.

Next, the space 53 is filled with a soft resin N (JIS K7215 resin having a shore a hardness of 90 or less) after melting through the inlet 55.

The distance between the inner surfaces of the molds 51-1 and 51-2 at the positions corresponding to the tip tapered portions 31A becomes shorter so that the tip becomes thinner toward the tip side, and the inner surfaces come into contact with the protruding surface 29a, thereby preventing the hard member 17 from moving toward the tip side. Therefore, even when the resin pressure of the molten soft resin N filled through the inlet 55 is applied, the hard member 17 is positioned without moving in the X direction.

Thereafter, the soft resin N is cured, thereby forming the first soft resin 22, the soft portion 26, and the handle body 31. A parting line of the minute ridge is formed on the surface of the soft portion 26 at a position (approximately the middle position in the Z direction) opposite to the joint surface of the mold 51-1 and the mold 51-2.

Thereby, the shank 11 having the head 14, the neck 15 and the shank 16 is formed. Thereafter, the shank 11 is removed from the second mold 51.

Next, as shown in fig. 1, hair bundles 12-1 are implanted into the plurality of implantation holes 21-2 of the head 11. Thus, the toothbrush 10 of the present embodiment shown in fig. 1 was manufactured.

As a method of tufting the tufts 12, for example, the following flat wire type tufting method can be used: after the tufts 12-1 are folded in half, flat wires (a plate made of metal (e.g., brass) having a relatively thin thickness) are sandwiched inside the tufts 12-1, and the tufts 12-1 sandwiching the flat wires are planted in the planting holes 21-2.

In the present embodiment, the case of the hair-planting method using the flat wire type hair-planting as the hair bundle 12-1 is described as an example, but instead of this method, for example, the following method may be used: a hot melt method in which the lower end of the tufts 12-1 is pressed into and fixed to the resin (soft resin or hard resin) constituting the head 14, an in-mold injection method in which the lower end of the tufts 12-1 is heated to form a molten mass, and then the molten resin is introduced into a mold, or the like.

While the preferred embodiments of the present invention have been described in detail, the present invention is not limited to the specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims.

For example, in the above-described embodiment, the structure in which the soft portion 26 is provided at the tip end portion of the head portion 14 has been described, but the present invention is not limited thereto, and as shown in the side view of fig. 13 and the front view of fig. 14, the soft portion 26 may be provided from the deformed portion 15A to the rear end side while including the deformed portion 15A of the neck portion 15.

The present invention can be widely applied to a so-called single-tuft toothbrush having one tuft of bristles, a toothbrush having a tongue coating removing portion, and the like as a toothbrush.

In the above embodiment, the toothbrush 10 in which the neck 15 having the width in the second direction (Y direction) smaller than the width of the head 14 (the maximum width in the Y direction) is arranged between the bristle surface 21-1b and the handle 16 has been described, but the present invention is not limited to this configuration, and, for example, a toothbrush in which a portion having the width in the Y direction equal to the maximum width of the head 14 is present between the bristle surface 21-1b and the handle 16 is also included in the present invention. In this case, the deformed portion is disposed as the neck portion, and at least a part of the hard member is housed inside from the deformed portion toward the rear end side, and the soft portion made of soft resin is disposed.

Industrial applicability

The present invention can be used for toothbrushes that inhibit oral lesions of a user.

Symbol description

A toothbrush, 11 handle, 12 bristle part, 14 head, 15 neck, 15A deformation, 16 handle, 17 hard part, 21 base part, 21-1 base part body, 21-1A bottom surface, 21-1A tip part, 21-1B bristle surface (first exposed part), 21-1B bristle hole, 21-2 support part, 21-2a protruding surface, 22 first soft resin, 25 core, 25-1 first part, 25-1A sectioned surface, 25-2 second part, 26 soft part, 27 second soft resin, 29 protruding part, 29a protruding surface, 31 handle body, 31A tip tapered part, 32-1, 32-2 annular recessed part (second deformation), 34 first rib, 35 second rib, 37 third, 41 first mold, 41-1, 41-2, 51-1, 51-2 mold, 43, 53 space, 45, 55 lead-in inlet, 51 second mold, R1, R2 diameter, S1, S2, T1, W1 width, W1, W2 first protruding part, W2 width.

Claims (11)

1. A toothbrush, characterized by comprising:

a head part having a bristle-planting surface on a distal end side, the bristle-planting surface being provided with bristle parts;

a handle disposed on a rear end side with respect to the head; and

a neck connecting the head and the handle,

the neck portion has a region which is covered with a soft resin and accommodates therein a hard member formed of a hard resin extending in the extending direction of the neck portion,

the width of the hard member in the neck portion in a first direction orthogonal to the bristle surface is larger than the width of the hard member in the neck portion in a second direction parallel to the bristle surface and orthogonal to the extending direction,

applying a force in the second direction more easily deforms the neck than applying a force in the first direction when pressing the bristle part,

the hard member has:

a base member including the bristle surface and having a plurality of bristle holes to form a part of the head;

a first portion having one end integrally formed with a rear end of the base member, disposed on the neck portion, and extending in an extending direction of the neck portion, the first portion having a uniform thickness in the extending direction and penetrating the neck portion: and

A second portion having one end integrated with the other end of the first portion, extending in the extending direction and disposed at a part of the shank,

a plurality of protruding portions protruding integrally with other portions of the hard member are formed in the second portion, the plurality of protruding portions being exposed in a circumferential direction around an axis extending in the extending direction,

the portion of the second portion other than the plurality of protruding portions and the first portion are covered with a soft resin in a non-exposed state over the entire circumferential area centered on the axis,

the plurality of protruding portions have a shape that enables the soft resin to flow through the outer peripheral surface of the second portion located on the rear end side of the plurality of protruding portions and then flow through the plurality of protruding portions to the front end side of the base member,

the protruding surface of the protruding portion is inclined so as to be farther from the axis as it is closer to the rear end side,

the plurality of protruding parts have protruding parts exposed on the bristle surface side and protruding parts exposed on the opposite side of the bristle surface.

2. The toothbrush of claim 1, wherein the toothbrush comprises,

In a cross section obtained when a central portion of the neck portion in the extending direction is cut with a surface orthogonal to the extending direction, a ratio of an area of the cross section of the hard member to an area of the cross section of the neck portion is 5% or more and less than 50%.

3. The toothbrush according to claim 2, wherein,

the cross-sectional shape of the cross-section of the hard member is any one of an oval, an oblong, a rectangular, a diamond, and a star.

4. The toothbrush according to any one of claim 1 to 3, wherein,

the hard component has a first portion disposed on the neck,

the width of the first portion in the second direction is 1.5mm or more and 2.0mm or less.

5. The toothbrush according to any one of claim 1 to 3, wherein,

the hard component has a first portion disposed on the neck,

the width of the first portion in the first direction is 1.5mm or more and 3.0mm or less.

6. The toothbrush of claim 4, wherein the toothbrush comprises,

the width of the first portion in the first direction is 1.5mm or more and 3.0mm or less.

7. The toothbrush according to any one of claim 1 to 3, wherein,

The cross-sectional shape of the cross-sectional surface obtained when the first portion is cut by a surface orthogonal to the extending direction is an ellipse or an oblong.

8. The toothbrush according to any one of claim 1 to 3, wherein,

the plurality of protruding portions are arranged such that adjacent protruding portions protrude at intervals in the circumferential direction on the outer peripheral surface of the second portion.

9. The toothbrush according to any one of claim 1 to 3, wherein,

the diameter of the portion of the second portion where the plurality of protrusions are provided is the largest,

the shape of the portion of the second portion that is disposed on the rear end side of the shank with respect to the plurality of protruding portions is such that the diameter becomes smaller from the plurality of protruding portions toward the rear end side of the shank.

10. The toothbrush according to any one of claim 1 to 3, wherein,

among the cut surfaces obtained when the protruding portion is cut with a surface orthogonal to the extending direction,

the closest distance between the end points of the two protruding portions opposing in the second direction on the outer peripheral surface of the second portion is larger than the distance between the two end points of the protruding portion between the two protruding portions on the outer peripheral surface of the second portion.

11. The toothbrush according to any one of claim 1 to 3, wherein,

the soft portion of the shank portion has a tip tapered portion that tapers toward a tip side, and the protruding portion is formed in the tip tapered portion.