WO2018110299A1 - Toothbrush and method for manufacturing toothbrush - Google Patents

Abstract

The purpose of the present invention is to provide a toothbrush capable of obtaining a highly customized feel while achieving good cleaning performance and feeling of use. The toothbrush has: a head portion (2) having a bristle-planted surface (20) at the tip side in the longitudinal direction; a handle portion (6) disposed further towards the rear side than the head portion; and a neck portion (4) disposed between the bristle-planted surface and the handle portion. The handle portion is provided with: a plurality of grip pieces (31) formed of a hard resin, and branching from the boundary with the neck portion to extend toward the rear side; and a soft portion (41) formed of a soft resin in an elongated shape, extending toward the rear side, and having a plurality of grip pieces disposed around the outside of a cross-section perpendicular to the longitudinal direction. The end part of the rear side of at least one of the grip pieces is provided separated from the other grip pieces.

Description

Toothbrush and toothbrush manufacturing method

The present invention relates to a toothbrush and a method for manufacturing a toothbrush.
This application claims priority based on Japanese Patent Application No. 2016-240153 filed in Japan on December 12, 2016 and Japanese Patent Application No. 2016-240154 filed on Japan on December 12, 2016, The contents are incorporated here.

¡General toothbrushes that consist entirely of a hard material in the handle part have a hard grip part and a low fit. With such a handle portion, it is easy to slide fingers during tooth brushing behavior, and it is difficult for an elderly person with a low grip strength or a handy capper to stably hold the handle portion. In order to improve these problems, the handle of the toothbrush needs to have a high fit, and various studies have been conducted from the viewpoint of shape and material.

As a specific measure, there is provided a toothbrush in which a soft material having excellent gripping force is covered with a soft material excellent in gripping force or a whole periphery of a handle portion so as to prevent the finger from slipping (see, for example, Patent Document 1). Further, in Patent Document 2, in a two-color molded handle made of a soft resin and a hard resin, a soft material is provided at the core of the grip portion, and the periphery thereof is made of a hard resin and extends from the neck portion to the rear end side. The toothbrush handle part which improved the fit by connecting with a support | pillar is disclosed.

JP 2006-466 Gazette Special table 2008-544785 gazette

However, the toothbrush described in Patent Document 1 uses a hard material for the core, has low followability to the hand, and has not achieved a sufficient fit. Moreover, the soft material (for example, A hardness of 30 or more) itself used for the existing toothbrush handle part itself is poor in flexibility and hardly deformed, so that the fit is insufficient.

Further, in the toothbrush described in Patent Document 2, the struts of the hard part are connected at two positions on the rear end side from the neck part, and the region where the soft resin is deformed when grasped is limited. Therefore, in the toothbrush described in Patent Document 2, the entire handle is difficult to deform and a good fit cannot be obtained.

Therefore, it is conceivable that the handle portion is made of only a soft material with ultra-low hardness (for example, A hardness is less than 30). In that case, the handle portion can be secured, however, the handle portion loses rigidity, and at the time of brushing. Since the applied force is not transmitted to the teeth, it is difficult to brush the teeth and the cleaning power is reduced. In addition, the soft resin having an extremely low hardness often causes stickiness due to bloom / bleed out due to change over time, which causes a problem in feeling of use (tactile sensation).

The present invention has been made in consideration of the above points, and an object of the present invention is to provide a toothbrush and a method of manufacturing a toothbrush that can obtain a high fit while ensuring a good cleaning power and a feeling of use.

According to the first aspect of the present invention, the head portion having a flocked surface on the front end side in the length direction, the handle portion disposed on the rear end side from the head portion, the flocked surface and the handle portion. A plurality of grip pieces extending from the boundary with the neck portion and extending to the rear end side, and a long shape made of a soft resin. And a soft part in which the plurality of gripping pieces are arranged around the outside in a cross section orthogonal to the length direction, and at least one of the gripping pieces includes the rear piece A toothbrush is provided in which an end portion on an end side is provided separately from the other gripping pieces.

Further, in the toothbrush according to one aspect of the present invention, the plurality of grip pieces are provided such that end portions on the rear end side are provided separately from each other.

Further, in the toothbrush according to one aspect of the present invention, the plurality of gripping pieces are arranged at positions that do not overlap each other in a direction orthogonal to the flocked surface.

The toothbrush according to one aspect of the present invention is characterized in that the toothbrush includes an axial portion extending in a direction orthogonal to the flocked surface from the grip piece.

Further, in the toothbrush according to the aspect of the present invention, the tip of the shaft-like portion is disposed flush with the outer peripheral surface of the soft portion or at a position recessed from the outer peripheral surface of the soft portion. And

Further, in the toothbrush according to one aspect of the present invention, three or more and five or less gripping pieces are arranged. Moreover, the toothbrush which concerns on 1 aspect of the said invention WHEREIN: The said holding piece is arrange | positioned three, It is characterized by the above-mentioned.

In the toothbrush according to one aspect of the present invention, the soft portion is formed integrally with the gripping piece.

Further, in the toothbrush according to one aspect of the present invention, the soft portion is fixed to the grip piece with an adhesive.

According to the second aspect of the present invention, the head portion having a flocked surface on the front end side in the length direction, the handle portion disposed on the rear end side from the head portion, the flocked surface and the handle portion. The handle portion is formed of a hard resin, is branched from a boundary with the neck portion and extends to the rear end side, and is formed of a soft resin. A plurality of gripping pieces extending in a long shape from the boundary with the neck portion to the rear end side, and having a plurality of gripping pieces arranged around the outside in a cross section orthogonal to the length direction. Are arranged at positions that do not overlap each other in a direction perpendicular to the flocked surface, and at least one end on the rear end side is provided separately from the other gripping pieces, and the soft portion is A through hole extending in a direction perpendicular to the flocked surface , The through hole has one end opening to face the said gripping pieces and the other end toothbrush is characterized in that an opening is exposed to the outside is provided.

Further, in the toothbrush according to one aspect of the present invention, a plurality of the through holes are arranged at positions facing each of the plurality of gripping pieces.

Further, in the toothbrush according to one aspect of the present invention, a plurality of the through holes are arranged along the gripping piece for each of the plurality of gripping pieces.

Further, in the toothbrush according to one aspect of the present invention, the through holes are arranged in a number of 3 or more and 10 or less for each of the plurality of gripping pieces.

Moreover, the toothbrush which concerns on 1 aspect of the said invention WHEREIN: The said through-hole exposes and opens the 1st through-hole exposed to one side of the direction orthogonal to the said flocked surface, and the 2nd exposed and opened to the other side. Including a through hole.

Further, in the toothbrush according to one aspect of the present invention, the plurality of grip pieces are provided such that end portions on the rear end side are provided separately from each other.

Further, in the toothbrush according to one aspect of the present invention, three or more and five or less gripping pieces are arranged. Moreover, the toothbrush which concerns on 1 aspect of the said invention WHEREIN: The said holding piece is arrange | positioned three, It is characterized by the above-mentioned.

Further, in the toothbrush according to one aspect of the present invention, in the cross section orthogonal to the length direction, the outer contour of the soft part is disposed inside a circle circumscribing the plurality of gripping pieces. And

According to the third aspect of the present invention, the head portion having a flocked surface on the front end side in the length direction, the handle portion disposed on the rear end side from the head portion, the flocked surface and the handle portion. A method of manufacturing a toothbrush having a neck portion disposed therebetween, forming a part of the handle portion, branching from a boundary with the neck portion, extending to the rear end side and orthogonal to the flocked surface A plurality of gripping pieces that are arranged at positions that do not overlap each other in the direction and at least one end on the rear end side is separated from other gripping pieces, together with the head portion and the neck portion, 1st process shape | molded as a hard part with a hard resin using 1 metal mold | die, it comprises a part of the said handle | steering-wheel part, it is elongated from the boundary with the said neck part to the said rear end side, and the said length Outside perimeter in cross section perpendicular to direction A second step of integrally molding the soft part in which the plurality of gripping pieces are arranged with the hard part by a soft resin using a second mold that houses the hard part therein, In the second step, the second mold is located on the other side by a holding portion extending from the mold located on one side in the direction orthogonal to the flocked surface to the other side in the direction orthogonal to the flocked surface. A method for manufacturing a toothbrush is provided, wherein the holding piece is held in a housing portion of a mold.

Further, in the method for manufacturing a toothbrush according to one aspect of the present invention, after the second step, one end of the soft portion is opened by the holding portion so as to face the grip piece, and the other end is exposed to the outside. A through hole that is open is formed.

In the present invention, it is possible to provide a toothbrush and a method for manufacturing a toothbrush that can obtain a high fit while ensuring a good cleaning power and a feeling of use.

It is a figure which shows embodiment of this invention, Comprising: It is a top view of the toothbrush 1 which concerns on 1st Embodiment. 2 is a side view of the toothbrush 1. FIG. FIG. 3 is a cross-sectional view taken along line AA in FIG. 2. It is sectional drawing of the 1st metal mold | die M1 used at a 1st process. It is sectional drawing of the 2nd metal mold | die M2 used at a 2nd process. It is sectional drawing of the 2nd metal mold | die M2 used at a 2nd process. It is the figure which cut the handle | steering-wheel part 6 in the toothbrush 1 which concerns on 2nd Embodiment in the surface parallel to a YZ plane. It is sectional drawing of the 2nd metal mold | die M2 used at the 2nd process of 2nd Embodiment. It is the figure which cut the handle | steering-wheel part 6 in the toothbrush 1 which concerns on 3rd Embodiment by the surface parallel to a YZ plane. It is sectional drawing of the 2nd metal mold | die M2 used at the 2nd process of 3rd Embodiment. It is a figure which shows embodiment of this invention, Comprising: It is a top view of the toothbrush 1 which concerns on 4th Embodiment. 2 is a side view of the toothbrush 1. FIG. FIG. 12 is a cross-sectional view taken along line AA in FIG. 11. It is sectional drawing of the 2nd metal mold | die M2 used at the 2nd process of the manufacturing method of the toothbrush which concerns on 4th Embodiment. It is sectional drawing of the 2nd metal mold | die M2 used at the said 2nd process.

Hereinafter, embodiments of the toothbrush and the method of manufacturing the toothbrush of the present invention will be described with reference to FIGS. 1 to 5.
The following embodiments show one aspect of the present invention and do not limit the present invention, and can be arbitrarily changed within the scope of the technical idea of the present invention. Moreover, in the following drawings, in order to make each configuration easy to understand, the actual structure is different from the scale and number of each structure.

[First Embodiment]
FIG. 1 is a plan view of the toothbrush 1 according to the first embodiment, and FIG. 2 is a side view of the toothbrush 1.
The toothbrush 1 in FIG. 1 includes a head portion 2 having a substantially square shape in plan view disposed on the front end side in the length direction, a neck portion 4 extending from the head portion 2 to the rear end side, and a neck portion 4 A substantially elongated handle body 10 having a handle portion 6 extending on the rear end side and a flocked portion (not shown) provided on the head portion 2 are provided.

The head portion 2 is formed in a substantially rectangular flat plate shape in which the length direction of the handle body 10 is long and the top portion on the neck portion 4 side is cut off with a curve in plan view, and the flocked surface which is the upper surface in FIG. In FIG. 20, a plurality of flock holes 22 are formed. A hair bundle (not shown) in which the bristles are bundled is planted in the tuft hole 22 to form a tuft portion including a plurality of tufts.

In this embodiment, the length direction of the handle body 10 is the X direction, the width direction parallel to the flocked surface 20 and perpendicular to the length direction of the handle body 10 is the Y direction, and the thickness is perpendicular to the flocked surface 20. The vertical direction is referred to as the Z direction. In addition, the side on which the flocked surface 20 faces is referred to as the front surface, and the side opposite to the side on which the flocked surface 20 faces is referred to as the back surface.

The size of the head portion 2 can be determined in consideration of the operability in the oral cavity.
If the width of the head portion 2 is too large, the operability in the oral cavity will be reduced, and if it is too small, the number of hair bundles to be implanted will be too small, and the cleaning effect will be easily impaired. For this reason, the width of the head portion 2 is, for example, 5 to 13 mm.

As the thickness of the head portion 2 is thinner, the operability in the oral cavity is improved, but if it is too thin, the strength of the head portion 2 tends to be insufficient. For this reason, the thickness of the head portion 2 can be determined in consideration of the material of the handle body 10 and the like, and is preferably 1.5 to 5 mm, and more preferably 2 to 3 mm. If the length of the head part 2 is too long, the operability in the oral cavity is liable to be impaired, and if it is too short, the number of hair bundles to be implanted becomes too small and the cleaning effect is liable to be impaired. For this reason, the length of the head portion 2 is appropriately determined in the range of 10 to 26 mm.

The shape of the flock hole 22 is not particularly limited, and examples thereof include a circle such as a perfect circle or an ellipse, and a polygon such as a triangle and a rectangle. The number of flock holes 22 is not particularly limited, and is 10 to 60, for example. The diameter of the flock hole 22 is determined according to the desired thickness of the hair bundle 23, and is set to 1 to 3 mm, for example. The arrangement pattern of the flock holes 22 is not particularly limited, and may be any arrangement pattern such as a so-called grid pattern or zigzag pattern.

The bristles constituting the hair bundle 23 are bristles (taper hairs) whose diameter gradually decreases toward the bristles, and bristles (straight bristles) having substantially the same outer diameter except for the rounded portion of the bristles. Is mentioned. The material of the hair is, for example, polyamide such as 6-12 nylon and 6-10 nylon, polyester such as PET, PBT, polytrimethylene terephthalate (PTT), PEN, polybutylene naphthalate (PBN), and polyolefin such as PP. Synthetic resin materials such as olefin elastomers and styrene elastomers can be used. These resin materials may be used individually by 1 type, and may be used in combination of 2 or more type. Further, the bristle may have a multi-core structure having a core part and at least one or more sheath parts provided outside the core part.

The cross-sectional contour of the hair is not particularly limited, and is, for example, a circle such as a perfect circle or an ellipse, a polygon such as a triangle, a rectangle, a pentagon, or a hexagon, a star, a three-leaf clover, or a four-leaf clover. Etc.

The thickness of the hair is not particularly limited, and is 3 to 11 mil (1 mil = 1/1000 inch = 0.025 mm) when the cross-sectional outline is circular. The hair bundle may be composed of all the hairs having the same thickness, or two or more hairs having different thicknesses may be combined.

The hair length is preferably 8 mm to 15 mm for adults and 6 mm to 12 mm for children, for example. In addition, from the viewpoint of usability in the oral cavity and usability, it is preferable to shorten the hair length of the hair as the diameter of the hair selected is smaller. Further, a plurality of hairs having different thicknesses may be used in combination depending on purposes such as a feeling of use, a feeling of cleaning, a cleaning effect, and durability.

The neck portion 4 connects the head portion 2 and the handle portion 6. The neck portion 4 extends from the front end boundary with the head portion 2 to the handle portion 6 with substantially the same diameter, and then expands to reach the rear end side boundary with the handle portion 6. The rear end side boundary is, for example, the end point of the diameter expansion of the neck portion 4 (that is, the end point of the straight line that forms both edges of the widened portion or the bending direction of the curve that forms both edges of the widened portion in plan view) Is a position (inflection point)).

As an example, the width of the neck portion 4 is preferably 3.0 to 4.5 mm, and more preferably 3.0 to 4.2 mm. When the width of the neck portion 4 is equal to or greater than the lower limit value, it is easy to suppress the strength of the neck portion 4 from being lowered, and the durability of the toothbrush 1 is enhanced. Furthermore, the toothbrush 1 does not become too soft, and a good feeling of use is easily obtained. Moreover, the operativity in the oral cavity of the toothbrush 1 is improved as the width | variety of the neck part 4 is below the said upper limit. Further, the hair can reach every corner of the oral cavity, and the dirt removal effect in the oral cavity is further enhanced.
When the width of the neck portion 4 is not constant, the width of the neck portion 4 means the minimum width of the neck portion 4.

As an example, the thickness of the neck portion 4 is preferably 3.0 to 4.5 mm, and more preferably 3.0 to 4.2 mm. When the thickness is equal to or more than the lower limit value, it is easy to suppress the strength of the neck portion 4 from being lowered, and the durability of the toothbrush 1 is enhanced. Furthermore, the toothbrush 1 does not become too soft, and a good feeling of use is easily obtained. Moreover, the operativity in the oral cavity of the toothbrush 1 is improved as the thickness of the neck part 4 is below the said upper limit. Further, the hair can reach every corner of the oral cavity, and the dirt removal effect in the oral cavity is further enhanced.
When the thickness of the neck portion 4 is not constant, the thickness means the minimum thickness of the neck portion 4.

The length of the neck portion 4 can be determined in consideration of the length of the head portion and the like, for example, a length of 30 to 90 mm. When the length of the neck part 4 is not less than the above lower limit value, it becomes easy to reach the hair to every corner in the oral cavity, and the dirt removal effect in the oral cavity is further enhanced. When the length of the neck portion 4 is not more than the above upper limit value, the operability of the toothbrush 1 in the oral cavity can be further enhanced.

The handle portion 6 has a plurality of (three in the present embodiment) gripping pieces 31a, 31b, 31c (referred to as the gripping piece 31 as appropriate) extending from the boundary with the neck portion 4 to the rear end side, And a soft portion 41 formed in a scale shape and extending toward the rear end side. The gripping pieces 31a, 31b, and 31c are formed in a substantially arc shape whose central portion is convex outward with respect to both ends in the length direction. The outer side means a side away from the center of the region surrounded by the gripping pieces 31a, 31b, 31c in a cross section orthogonal to the length direction. The gripping pieces 31a, 31b, 31c are provided with end portions on the rear end side separated from each other.

3 is a cross-sectional view taken along line AA in FIG.
As shown in FIG. 3, the cross-sectional shape of the soft portion 41 parallel to the YZ plane is a substantially elliptical shape whose major axis is the Y-axis direction. Also, as shown in FIGS. 1 and 2, the soft part 41 has a plan view shape and a side view shape that are thickest at the central portion in the length direction and have a substantially arc-shaped outer shape toward the outside in the length direction. It is a shape that becomes gradually thinner at the contour.

The soft part 41 is made of a soft resin. As the soft resin, for example, a soft resin having a hardness of JIS K 7215 Shore A of 30 or less may be used. Examples of such a soft resin include elastomer resins such as polyolefin elastomers, styrene elastomers, polyester elastomers, polyurethane elastomers, and silicone resins.

The grip pieces 31 a, 31 b, and 31 c are arranged around the outside of the soft portion 41. The gripping piece 31a is arranged at a substantially central portion in the Y direction on the + Z side of the soft portion 41. The gripping piece 31b is arranged on the + Z side of the soft part 41 on the −Z side with respect to the central part in the Y direction. The gripping piece 31c is arranged substantially symmetrically with the gripping piece 31b on the −Z side of the soft portion 41 and on the −Y side of the central portion in the Y direction.

The gripping pieces 31a, 31b, and 31c are arranged at positions that do not overlap each other in a direction orthogonal to the flocked surface 20 (that is, the Z direction). That is, the gripping pieces 31a, 31b, and 31c are disposed at positions that do not overlap each other when viewed in the Z direction. The surfaces of the gripping pieces 31a, 31b, and 31c that face the soft portion 41 are formed flush with the outer peripheral surface of the soft portion 41 (substantially elliptical in cross section). The surfaces of the gripping pieces 31a, 31b, and 31c opposite to the surface facing the soft portion 41 have a substantially arc shape in which the cross-sectional shape swells outward with a curvature larger than the curvature of the surface facing the soft portion 41.

The gripping piece 31a has a finger rest 51 extending in the X direction in the vicinity of the distal end side. The finger rest 51 is formed in a concave curved surface having a substantially arcuate cross-sectional contour that is deepest at the center and gradually becomes shallower toward the edge. By providing the finger contact portion 51 on the distal end side of the grip piece 31a, when the grip piece 31 is gripped with a palm, for example, the handle portion 6 can be stably gripped by placing the thumb against the finger contact portion 51. This improves operability during brushing.

The gripping piece 31 constitutes a hard portion 50 that is integrally molded with a hard resin together with the head portion 2 and the neck portion 4. Specific examples of such a hard resin include, for example, polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polycyclohexylene dimethylene terephthalate (PCT), polyacetal (POM), polystyrene (PS). , Acrylonitrile / butadiene / styrene resin (ABS), cellulose propionate (CP), polyarylate, polycarbonate, acrylonitrile / styrene copolymer resin (AS), etc. can do. The said hard resin may be used individually by 1 type, and may be used in combination of 2 or more type as appropriate.
In particular, the thickness of the gripping pieces 31a, 31b, 31c can be set in consideration of the hardness of the soft portion 41. When the gripping piece 31 is made of polypropylene resin, the thickness is preferably 0.8 to 1.2 mm. Can be from 0.9 to 1.0 mm.

In the handle body 10 of the toothbrush 1 having the above-described configuration, the first step of molding the hard portion 50 by injection molding using the first mold and the second step of molding the soft portion 41 by injection molding using the second mold. It is manufactured through a process.

The first mold used in the first step is, for example, a pair of molds (for example, a fixed mold and a movable mold, or at a position between the flocked surface 20 and the back surface of the head unit 2 in parallel with the XY plane. A parting line that is a joint surface between the upper mold and the lower mold (hereinafter referred to as the upper mold and the lower mold) is set. As shown in FIG. 4, the first mold M <b> 1 includes an upper mold M <b> 11 that mainly molds the surface on the flocked surface 20 side and a flocked surface 20 mainly in the region where the handle portion 6 is molded in the hard portion 50. And a lower mold M12 for molding the reverse side of the opposite side. In the upper mold M11 and the lower mold M12, in the region where the gripping pieces 31a, 31b, and 31c are formed, the surface along the outer peripheral surface of the soft portion 41 is a parting line.

The upper mold M11 is opposed to the surface 32a that forms the surface of the gripping piece 31a on the flocked surface 11 side, the surface 32b that molds the surface that faces the soft portion 41 of the gripping piece 31b, and the soft portion 41 of the gripping piece 31c. And a surface 32c for forming the surface.

The lower mold M12 includes a surface 33a that forms the back surface of the gripping piece 31a, a surface 33b that forms a surface opposite to the surface facing the soft portion 41 of the gripping piece 31b, and a soft portion 41 of the gripping piece 31c. And a surface 33c for forming a surface opposite to the surface opposite to the surface.

When the upper mold M11 and the lower mold M12 are clamped, the cavity 34a for molding the grip piece 31a surrounded by the surface 32a and the surface 33a, and the grip surrounded by the surface 32b and the surface 33b A cavity 34b for molding the piece 31b and a cavity 34c for molding the gripping piece 31c surrounded by the surface 32c and the surface 33c are formed. Although not shown, when the upper mold M11 and the lower mold M12 are clamped, cavities for forming the head portion 2 and the neck portion 4 are formed.

By filling the cavity in the mold with the hard resin melted in a state where the upper mold M11 and the lower mold M12 are clamped and cooling for a predetermined time, the upper mold M11 and the lower mold M12 are separated from each other, The hard part 50 is molded.

The hard part 50 molded by the first mold M1 in the first step is accommodated in the second mold M2. That is, a part of the hard part 50 forms a cavity for molding the soft part 41 together with the second mold M2. FIG. 5 is a cross-sectional view of the second mold M2 taken along the XZ plane at the approximate center of the toothbrush 1 in the width direction. FIG. 6 is a cross-sectional view of the second mold M2 taken along the XZ plane at the center of the handle portion 6 in the length direction.

As shown in FIG. 5, the upper mold M21 of the second mold M2 accommodates part of the accommodating portions 2M and 4M that accommodate the head portion 2 and the flocked surface 20 side of the neck portion 4 and the gripping piece 31a. As shown in FIG. 6, the housing portion 31 a </ i> M has a surface 35 that molds the outer peripheral surface of the soft portion 41 on the flocked surface 20 side. The surface 35 is formed flush with the surface facing the soft portion 41 of the grip piece 31a accommodated in the accommodating portion 31aM.

A suction port 61 is opened on the opposite side of the housing part 31aM from the lower mold 22. A negative pressure suction device (not shown) is connected to the suction port 61 and sucks the gripping piece 31a housed in the housing portion 31aM with negative pressure. As shown in FIG. 5, a plurality (two in FIG. 5) of suction ports 61 are arranged at intervals in the length direction.

The lower mold M22 of the second mold M2 includes a housing part 2M, 4M for housing the head part 2 and the neck part 4 on the side of the flocked surface 20, a housing part 31bM for housing the gripping piece 31b, and a gripping piece 31c. And a surface 36 for molding the outer peripheral surface of the soft portion 41 opposite to the flocked surface 20 side. The surface 36 is formed flush with the gripping piece 31b accommodated in the accommodating portion 31bM and the surface facing the soft portion 41 of the grasping piece 31c accommodated in the accommodating portion 31cM.

The gripping pieces 31a, 31b, 31c, the surface 35 of the upper mold M21, and the surface 36 of the lower mold M22 form a cavity 41M for molding the soft portion 41.

A suction port 62 is opened on the side opposite to the upper mold 21 in the accommodating portion 31bM. A negative pressure suction device (not shown) is connected to the suction port 62 and sucks the gripping piece 31b accommodated in the accommodating portion 31bM with negative pressure. A suction port 63 is opened on the side opposite to the upper mold 21 in the housing portion 31cM. A negative pressure suction device (not shown) is connected to the suction port 63 and sucks the gripping piece 31c housed in the housing portion 31cM with negative pressure. Similar to the suction port 61, a plurality of (for example, two) suction ports 62 and 63 are arranged at intervals in the length direction.

The hard part 50 is accommodated in the accommodating parts 2M, 4M, the accommodating part 31aM, the accommodating part 31bM, and the accommodating part 31cM inside the upper mold M21 and the lower mold M22. The gripping piece 31a of the hard part 50 accommodated inside the upper mold M21 and the lower mold M22 is sucked by the negative pressure suction device through the suction port 61 and held in the upper mold M21 (housing part 31aM). The The gripping pieces 31b, 31c of the hard part 50 accommodated in the upper mold M21 and the lower mold M22 are sucked by the negative pressure suction device through the suction ports 62, 63, and the lower mold M22 (accommodating part 31bM). , 31 cM).

In the state where the upper mold M21 and the lower mold M22 that accommodate the hard portion 50 are clamped, a melted soft resin is filled in the cavity in the mold, and after cooling for a predetermined time, from the upper mold M21 and the lower mold M22 By releasing the mold, the handle body 10 including the soft part 41 in which the gripping pieces 31a, 31b, 31 are arranged around the outside is formed.

Next, a hair bundle is implanted in the head portion 2 of the obtained handle body 10. As a method for flocking the hair bundle, the hair bundle is folded in two and a flat wire sandwiched between the two is driven into the flock hole 22 so that the hair bundle is planted, and the lower end of the hair bundle is melted to become the flocked portion. Examples thereof include a heat-sealing method in which the resin is pressed into a resin and fixed, and an in-mold method in which the bottom end of the hair bundle is heated to form a molten lump, and then the molten resin is injected into the mold to mold the flocked portion.

When using the toothbrush 1 having the above-described configuration, the head portion 2, the neck portion 4 and the gripping pieces 31a to 31c constitute the hard portion 50, so that the rigidity during brushing is ensured and the cleaning force is maintained, and the handle When the portion 6 is grasped, the gripping pieces 31a to 31c are elastically deformed and bent, and the elastic restoring force is transmitted to the palm, so that a high fit is imparted. In particular, the gripping pieces 31a to 31c in the toothbrush 1 are not restrained because the rear end portions are separated from each other, so that the elastic restoring force accompanying the bending of the gripping pieces 31a to 31c is efficiently transmitted to the palm.

In the toothbrush 1 configured as described above, when the handle portion 6 is gripped, the soft portion 41 is also elastically deformed in addition to the elastic deformation of the gripping pieces 31a to 31c. Therefore, the elastic restoring forces of the gripping pieces 31a to 31c and the soft portion 41 are combined, so that a high fit can be obtained in the entire handle portion 6. Here, for example, when the rear end sides of the gripping pieces 31a to 31c are connected, a space in which the soft portion 41 around which the gripping pieces 31a to 31c are arranged is deformed on the rear end side is restricted. On the other hand, in the toothbrush 1 of the present embodiment, since the rear end side ends of the gripping pieces 31a to 31c are separated from each other, the rear end side of the soft portion 41 can be freely deformed without being restricted, Flexibility improves and can contribute to creation of a high fit.

Furthermore, in the toothbrush 1 of this embodiment, since the grip pieces 31a to 31c are arranged around the outside of the soft part 41, the area where the soft part 41 is exposed and touched by the user can be reduced. Therefore, in the toothbrush 1 of this embodiment, it can suppress that a usability | use_condition falls by the stickiness resulting from the bloom / bleed-out which generate | occur | produces with a time-dependent change of a soft material.

In addition, in the toothbrush 1 of the present embodiment, since the gripping pieces 31a to 31c are arranged at positions that do not overlap each other in the direction orthogonal to the flocked surface 20, some mold parts intersect with the mold opening / closing direction. Without providing a mechanism for moving in the direction, as described above, the handle body 10 can be formed only with a mold that opens and closes in the Z direction, which contributes to a reduction in manufacturing costs.

[Second Embodiment]
Next, a second embodiment of the toothbrush 1 will be described with reference to FIGS. 7 and 8.
In these drawings, the same components as those of the first embodiment shown in FIGS. 1 to 6 are denoted by the same reference numerals, and the description thereof is omitted.

FIG. 7 is a cross-sectional view of the handle portion 6 of the toothbrush 1 according to the second embodiment taken along a plane parallel to the YZ plane.
As shown in FIG. 7, the handle portion 6 has a shaft-shaped portion 37a extending in the Z direction from the gripping piece 31a, a shaft-shaped portion 37b extending in the Z direction from the gripping piece 31b, and a shaft-shaped extending from the gripping piece 31c in the Z direction. Part 37c. The distal end of the shaft-shaped portion 37b and the distal end of the shaft-shaped portion 37c are arranged flush with the outer peripheral surface of the soft portion 41 on the flocked surface 20 side.
Other configurations are the same as those of the toothbrush 1 of the first embodiment.

FIG. 8 is a cross-sectional view of the second mold M2 taken along the XZ plane at the center in the length direction of the handle portion 6 in the toothbrush 1 according to the second embodiment.
As shown in FIG. 8, when the hard part 50 obtained in the first step is accommodated in the upper mold M21 and the lower mold M22, the tip of the shaft-shaped part 37a contacts the surface 36 of the lower mold M22. Touch. Thereby, the gripping piece 31a is housed and held in the housing portion 31aM without being bent and protruding into the cavity 41M. Similarly, when the hard portion 50 is accommodated in the upper mold M21 and the lower mold M22, the tip of the shaft-shaped portion 37b and the tip of the shaft-shaped portion 37c abut against the surface 35 of the upper mold M21. Thereby, the gripping piece 31b is housed and held in the housing portion 31bM without being bent and protruding into the cavity 41M. The gripping piece 31c is housed and held in the housing portion 31cM without being bent and protruding into the cavity 41M.
It is preferable to provide one or more shaft-shaped portions 37 at intervals in the length direction of the handle portion 6.
Further, as the cross-sectional shape of the shaft-shaped portion 37, a desired shape such as a circle, an ellipse, or a square can be selected.

Thereafter, the upper mold M21 and the lower mold M22 are clamped, and the cavity in the mold is filled with the soft resin melted, and after cooling for a predetermined time, the upper mold M21 and the lower mold M22 are separated from each other. Thus, the handle body 10 including the soft portion 41 in which the gripping pieces 31a, 31b, and 31 are arranged around the outside is formed.

Thus, in the toothbrush 1 of this embodiment, in addition to obtaining the same operation and effect as the toothbrush 1 of the first embodiment, the shaft-shaped portions 37a to 37c abut on the second mold M2. Can hold and hold the gripping pieces 31a to 31c in the storage portions 31aM to 31cM, respectively. Therefore, a separate mechanism for storing the gripping pieces 31a to 31c of the negative pressure suction device or the like in the storage portions 31aM to 31cM is separately provided. There is no need to provide the device, and it is possible to avoid an increase in the size and cost of the manufacturing apparatus.

[Third Embodiment]
Next, a third embodiment of the toothbrush 1 will be described with reference to FIGS. 9 and 10.
In these drawings, the same reference numerals are given to the same elements as those of the second embodiment shown in FIGS. 7 and 8, and the description thereof is omitted.

FIG. 9 is a cross-sectional view of the handle portion 6 of the toothbrush 1 according to the third embodiment taken along a plane parallel to the YZ plane.
As shown in FIG. 9, the tip of the shaft-shaped portion 37 a is disposed flush with the bottom surface of the recess 38 a formed on the outer peripheral surface on the back surface side of the soft portion 41. The tip of the shaft-shaped portion 37b is disposed flush with the bottom surface of the recess 38b formed on the outer peripheral surface of the soft portion 41 on the flocked surface 20 side. The tip of the shaft-shaped portion 37c is disposed flush with the bottom surface of the recess 38c formed on the outer peripheral surface of the soft portion 41 on the flocked surface 20 side.
Other configurations are the same as those of the toothbrush 1 of the second embodiment.

FIG. 10 is a cross-sectional view of the second mold M2 taken along the XZ plane at the center in the length direction of the handle portion 6 in the toothbrush 1 according to the second embodiment.
As shown in FIG. 10, the surface 35 of the upper mold M21 is provided with a convex portion 39b corresponding to the recess 38b and a convex portion 39c corresponding to the recess 38c. A convex portion 39a corresponding to the recess 38a is provided on the surface 36 of the lower mold M22.

When the hard part 50 obtained in the first step is accommodated in the upper mold M21 and the lower mold M22, the tip of the shaft-shaped part 37a comes into contact with the surface of the convex part 39a in the lower mold M22. Thereby, the gripping piece 31a is housed and held in the housing portion 31aM without being bent and protruding into the cavity 41M. Similarly, when the hard part 50 is accommodated in the upper mold M21 and the lower mold M22, the tip of the shaft-shaped part 37b abuts on the surface of the convex part 39b in the upper mold M21. Thereby, the gripping piece 31b is housed and held in the housing portion 31bM without being bent and protruding into the cavity 41M. Further, when the hard portion 50 is accommodated in the upper mold M21 and the lower mold M22, the tip of the shaft-shaped portion 37c comes into contact with the surface of the convex portion 39c in the upper mold M21. Thereby, the gripping piece 31c is housed and held in the housing portion 31cM without being bent and protruding into the cavity 41M.

Thereafter, the upper mold M21 and the lower mold M22 are clamped, and the cavity in the mold is filled with the soft resin melted, and after cooling for a predetermined time, the upper mold M21 and the lower mold M22 are separated from each other. Thus, the handle body 10 including the soft portion 41 in which the gripping pieces 31a, 31b, and 31 are arranged around the outside is formed.

As described above, in the toothbrush 1 of the present embodiment, in addition to obtaining the same operation and effect as the toothbrush 1 of the second embodiment, the tips of the shaft-shaped portions 37a to 37c are in contact with the bottom surfaces of the recesses 38a to 38c. Since the soft portions 41 are compressed and thinned when the gripping pieces 31a to 31c are gripped, the tips of the shaft-shaped portions 37a to 37c protrude from the outer peripheral surface of the soft portion 41. It becomes possible to suppress that.

[Fourth Embodiment]
Next, a fourth embodiment of the toothbrush 1 will be described with reference to FIGS. 11 to 15.
In these drawings, the same components as those of the first embodiment shown in FIGS. 1 to 6 are denoted by the same reference numerals, and the description thereof is omitted.

FIG. 11 is a plan view of the toothbrush 1, and FIG. 12 is a side view of the toothbrush 1.
The toothbrush 1 in FIG. 11 includes a head portion 2 having a substantially square shape in plan view disposed on the front end side in the length direction, a neck portion 4 extending from the head portion 2 to the rear end side, and the neck portion 4. A substantially elongated handle body 10 having a handle portion 6 extending on the rear end side and a flocked portion (not shown) provided on the head portion 2 are provided.

The head portion 2 is formed in a substantially rectangular flat plate shape in which the length direction of the handle body 10 is long, and the top portion on the neck portion 4 side is cut off with a curve in plan view, and the flocked surface which is the upper surface in FIG. In FIG. 20, a plurality of flock holes 22 are formed. A hair bundle (not shown) in which the bristles are bundled is planted in the tuft hole 22 to form a tuft portion including a plurality of tufts.

In this embodiment, the length direction of the handle body 10 is the X direction, the width direction parallel to the flocked surface 20 and perpendicular to the length direction of the handle body 10 is the Y direction, and the thickness is perpendicular to the flocked surface 20. The vertical direction is referred to as the Z direction. In addition, the side on which the flocked surface 20 faces is referred to as the front surface, and the side opposite to the side on which the flocked surface 20 faces is referred to as the back surface.

The size of the head portion 2 can be determined in consideration of the operability in the oral cavity.
If the width of the head portion 2 is too large, the operability in the oral cavity will be reduced, and if it is too small, the number of hair bundles to be implanted will be too small, and the cleaning effect will be easily impaired. For this reason, the width of the head portion 2 is, for example, 5 to 13 mm.

As the thickness of the head portion 2 is thinner, the operability in the oral cavity is improved, but if it is too thin, the strength of the head portion 2 tends to be insufficient. For this reason, the thickness of the head portion 2 can be determined in consideration of the material of the handle body 10 and the like, and is preferably 1.5 to 5 mm, and more preferably 2 to 3 mm. If the length of the head part 2 is too long, the operability in the oral cavity is liable to be impaired, and if it is too short, the number of hair bundles to be implanted becomes too small and the cleaning effect is liable to be impaired. For this reason, the length of the head portion 2 is appropriately determined in the range of 10 to 26 mm.

The shape of the flock hole 22 is not particularly limited, and examples thereof include a circle such as a perfect circle or an ellipse, and a polygon such as a triangle and a rectangle. The number of flock holes 22 is not particularly limited, and is 10 to 60, for example. The diameter of the flock hole 22 is determined according to the desired thickness of the hair bundle 23, and is set to 1 to 3 mm, for example. The arrangement pattern of the flock holes 22 is not particularly limited, and may be any arrangement pattern such as a so-called grid pattern or zigzag pattern.

The bristles constituting the hair bundle 23 are bristles (taper hairs) whose diameter gradually decreases toward the bristles, and bristles (straight bristles) having substantially the same outer diameter except for the rounded portion of the bristles. Is mentioned. The material of the hair is, for example, polyamide such as 6-12 nylon and 6-10 nylon, polyester such as PET, PBT, polytrimethylene terephthalate (PTT), PEN, polybutylene naphthalate (PBN), and polyolefin such as PP. Synthetic resin materials such as olefin elastomers and styrene elastomers can be used. These resin materials may be used individually by 1 type, and may be used in combination of 2 or more type. Further, the bristle may have a multi-core structure having a core part and at least one or more sheath parts provided outside the core part.

The cross-sectional contour of the hair is not particularly limited, and is, for example, a circle such as a perfect circle or an ellipse, a polygon such as a triangle, a rectangle, a pentagon, or a hexagon, a star, a three-leaf clover, or a four-leaf clover. Etc.

The thickness of the hair is not particularly limited, and is 3 to 11 mil (1 mil = 1/1000 inch = 0.025 mm) when the cross-sectional outline is circular. The hair bundle may be composed of all the hairs having the same thickness, or two or more hairs having different thicknesses may be combined.

The hair length is preferably 8 mm to 15 mm for adults and 6 mm to 12 mm for children, for example. In addition, from the viewpoint of usability in the oral cavity and usability, it is preferable to shorten the hair length of the hair as the diameter of the hair selected is smaller. Further, a plurality of hairs having different thicknesses may be used in combination depending on purposes such as a feeling of use, a feeling of cleaning, a cleaning effect, and durability.

The neck portion 4 connects the head portion 2 and the handle portion 6. The neck portion 4 extends from the front end boundary with the head portion 2 to the handle portion 6 with substantially the same diameter, and then expands to reach the rear end side boundary with the handle portion 6. The rear end side boundary is, for example, the end point of the diameter expansion of the neck portion 4 (that is, the end point of the straight line that forms both edges of the widened portion or the bending direction of the curve that forms both edges of the widened portion in plan view) Is a position (inflection point)).

As an example, the width of the neck portion 4 is preferably 3.0 to 4.5 mm, and more preferably 3.0 to 4.2 mm. When the width of the neck portion 4 is equal to or greater than the lower limit value, it is easy to suppress the strength of the neck portion 4 from being lowered, and the durability of the toothbrush 1 is enhanced. Furthermore, the toothbrush 1 does not become too soft, and a good feeling of use is easily obtained. Moreover, the operativity in the oral cavity of the toothbrush 1 is improved as the width | variety of the neck part 4 is below the said upper limit. Further, the hair can reach every corner of the oral cavity, and the dirt removal effect in the oral cavity is further enhanced.
When the width of the neck portion 4 is not constant, the width of the neck portion 4 means the minimum width of the neck portion 4.

As an example, the thickness of the neck portion 4 is preferably 3.0 to 4.5 mm, and more preferably 3.0 to 4.2 mm. When the thickness is equal to or more than the lower limit value, it is easy to suppress the strength of the neck portion 4 from being lowered, and the durability of the toothbrush 1 is enhanced. Furthermore, the toothbrush 1 does not become too soft, and a good feeling of use is easily obtained. Moreover, the operativity in the oral cavity of the toothbrush 1 is improved as the thickness of the neck part 4 is below the said upper limit. Further, the hair can reach every corner of the oral cavity, and the dirt removal effect in the oral cavity is further enhanced.
When the thickness of the neck portion 4 is not constant, the thickness means the minimum thickness of the neck portion 4.

The length of the neck portion 4 can be determined in consideration of the length of the head portion and the like, for example, a length of 30 to 90 mm. When the length of the neck part 4 is not less than the above lower limit value, it becomes easy to reach the hair to every corner in the oral cavity, and the dirt removal effect in the oral cavity is further enhanced. When the length of the neck portion 4 is not more than the above upper limit value, the operability of the toothbrush 1 in the oral cavity can be further enhanced.

The handle portion 6 has a plurality of (three in the present embodiment) gripping pieces 31a, 31b, 31c (referred to as the gripping piece 31 as appropriate) extending from the boundary with the neck portion 4 to the rear end side, And a soft portion 41 formed in a scale shape and extending toward the rear end side. The gripping pieces 31a, 31b, and 31c are formed in a substantially arc shape whose central portion is convex outward with respect to both ends in the length direction. The outer side means a side away from the center of the region surrounded by the gripping pieces 31a, 31b, 31c in a cross section orthogonal to the length direction. The gripping pieces 31a, 31b, 31c are provided with end portions on the rear end side separated from each other.

13 is a cross-sectional view taken along line AA in FIG.
As shown in FIG. 13, the cross-sectional shape of the soft part 41 parallel to the YZ plane is a substantially elliptical shape whose major axis is the Y-axis direction. Further, as shown in FIGS. 11 and 12, the soft portion 41 has a plan view shape and a side view shape that are thickest at the central portion in the length direction and have a substantially arc-shaped outer shape toward the outside in the length direction. It is a shape that becomes gradually thinner at the contour.

The soft part 41 is made of a soft resin. As the soft resin, for example, a soft resin having a hardness of JIS K 7215 Shore A of 30 or less may be used. Examples of such a soft resin include elastomer resins such as polyolefin elastomers, styrene elastomers, polyester elastomers, polyurethane elastomers, and silicone resins.

The grip pieces 31 a, 31 b, and 31 c are arranged around the outside of the soft portion 41. The gripping piece 31a is arranged at a substantially central portion in the Y direction on the + Z side of the soft portion 41. The gripping piece 31b is arranged on the + Z side of the soft part 41 on the −Z side with respect to the central part in the Y direction. The gripping piece 31c is arranged substantially symmetrically with the gripping piece 31b on the −Z side of the soft portion 41 and on the −Y side of the central portion in the Y direction. As shown in FIG. 13, in the cross section orthogonal to the length direction, the outer contour of the soft portion 41 is arranged inside a circle circumscribing the gripping pieces 31a, 31b, and 31c.

The gripping pieces 31a, 31b, and 31c are arranged at positions that do not overlap each other in a direction orthogonal to the flocked surface 20 (that is, the Z direction). That is, the gripping pieces 31a, 31b, and 31c are disposed at positions that do not overlap each other when viewed in the Z direction. The surfaces of the gripping pieces 31a, 31b, and 31c that face the soft portion 41 are formed flush with the outer peripheral surface of the soft portion 41 (substantially elliptical in cross section). The surfaces of the gripping pieces 31a, 31b, and 31c opposite to the surface facing the soft portion 41 have a substantially arc shape in which the cross-sectional shape swells outward with a curvature larger than the curvature of the surface facing the soft portion 41.

The gripping piece 31a has a finger rest 51 extending in the X direction in the vicinity of the distal end side. The finger rest 51 is formed in a concave curved surface having a substantially arcuate cross-sectional contour that is deepest at the center and gradually becomes shallower toward the edge. By providing the finger contact portion 51 on the distal end side of the grip piece 31a, when the grip piece 31 is gripped with a palm, for example, the handle portion 6 can be stably gripped by placing the thumb against the finger contact portion 51. This improves operability during brushing.

The gripping piece 31 constitutes a hard portion 50 that is integrally molded with a hard resin together with the head portion 2 and the neck portion 4. Specific examples of such a hard resin include, for example, polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polycyclohexylene dimethylene terephthalate (PCT), polyacetal (POM), polystyrene (PS). , Acrylonitrile / butadiene / styrene resin (ABS), cellulose propionate (CP), polyarylate, polycarbonate, acrylonitrile / styrene copolymer resin (AS), etc. can do. The said hard resin may be used individually by 1 type, and may be used in combination of 2 or more type as appropriate.
In particular, the thickness of the gripping pieces 31a, 31b, 31c can be set in consideration of the hardness of the soft portion 41. When the gripping piece 31 is made of polypropylene resin, the thickness is preferably 0.8 to 1.2 mm. Can be from 0.9 to 1.0 mm.

As shown in FIG. 13, the soft part 41 has through- holes 137a, 137b, 137c having a circular cross section extending in a direction (Z direction) orthogonal to the flocked surface 20. The through-hole (first through-hole) 137a is opened with the + Z side end facing the gripping piece 31a and the −Z side end exposed to the outside. The through-hole (second through-hole) 137b is opened with the −Z side end facing the gripping piece 31b and the + Z side end exposed to the outside. Similarly, the through-hole (second through-hole) 137c is opened with the −Z side end facing the gripping piece 31c and the + Z side end exposed to the outside.

As shown in FIGS. 11 and 12, the through-holes 137a are spaced apart from each other along the length direction of the gripping piece 31 including the position of the finger pad 51 and the position near the rear end side end of the gripping piece 31a. A plurality (four in this embodiment) are arranged. A plurality of (three in this embodiment) through-holes 137b are arranged at intervals along the gripping piece 31b so as to be positioned approximately in the middle of the through-hole 137a in the X direction. A plurality of (three in this embodiment) through-holes 137c are arranged at substantially the same position of the through-hole 137b in the X direction at intervals along the gripping piece 31c.

The number of the through holes 137a, 137b, and 137c is preferably 3 or more and 10 or less, respectively. When the number of the through holes 137a, 137b, and 137c is less than three, the deformation of the soft part 41 when the handle part 6 is grasped may be reduced, and the fit feeling that can be obtained may be reduced. There is a possibility that the holding pieces 31a, 31b, 31c are not stably held on the second mold by the shaft member in the second step. On the other hand, when the number of the through holes 137a, 137b, and 137c exceeds 10, there is a possibility that the deformation of the soft portion 41 becomes too large to obtain an appropriate fit. By setting the number of through holes 137a, 137b, and 137c to 3 or more and 10 or less, it is possible to stably hold the gripping pieces 31a, 31b, and 31c in the second mold in the second step. In addition, a high fit can be obtained when the handle portion 6 is grasped.
The cross-sectional shape of the through-hole 37 may be a desired shape such as a polygon such as a circle, an ellipse, a triangle, or a rectangle, or a polygon such as a star.

In the handle body 10 of the toothbrush 1 having the above-described configuration, the first step of molding the hard portion 50 by injection molding using the first mold and the second step of molding the soft portion 41 by injection molding using the second mold. It is manufactured through a process.

The first mold used in the first step is, for example, a pair of molds (for example, a fixed mold and a movable mold, or at a position between the flocked surface 20 and the back surface of the head unit 2 in parallel with the XY plane. A parting line that is a joint surface between the upper mold and the lower mold (hereinafter referred to as the upper mold and the lower mold) is set. As shown in FIG. 4, the first mold M <b> 1 includes an upper mold M <b> 11 that mainly molds the surface on the flocked surface 20 side and a flocked surface 20 mainly in the region where the handle portion 6 is molded in the hard portion 50. And a lower mold M12 for molding the reverse side of the opposite side. In the upper mold M11 and the lower mold M12, in the region where the gripping pieces 31a, 31b, and 31c are formed, the surface along the outer peripheral surface of the soft portion 41 is a parting line.

The upper mold M11 opposes the surface 32a that forms the surface of the gripping piece 31a on the flocked surface 11 side, the surface 32b that molds the surface facing the soft portion 41 of the gripping piece 31b, and the soft portion 41 of the gripping piece 31c. And a surface 32c for forming the surface.

The lower mold M12 includes a surface 33a that forms a surface on the back side of the gripping piece 31a, a surface 33b that forms a surface opposite to the surface facing the soft portion 41 of the gripping piece 31b, and a soft portion 41 of the gripping piece 31c. And a surface 33c for forming a surface opposite to the surface opposite to the surface.

When the upper mold M11 and the lower mold M12 are clamped, the cavity 34a for molding the grip piece 31a surrounded by the surface 32a and the surface 33a, and the grip surrounded by the surface 32b and the surface 33b A cavity 34b for molding the piece 31b and a cavity 34c for molding the gripping piece 31c surrounded by the surface 32c and the surface 33c are formed. Although not shown, when the upper mold M11 and the lower mold M12 are clamped, cavities for forming the head portion 2 and the neck portion 4 are formed.

By filling the cavity in the mold with the hard resin melted in a state where the upper mold M11 and the lower mold M12 are clamped and cooling for a predetermined time, the upper mold M11 and the lower mold M12 are separated from each other, The hard part 50 is molded.

The hard part 50 molded by the first mold M1 in the first step is accommodated in the second mold M2. That is, a part of the hard part 50 forms a cavity for molding the soft part 41 together with the second mold M2. FIG. 14 is a cross-sectional view of the second mold M2 taken along the XZ plane at the approximate center of the toothbrush 1 in the width direction. FIG. 15 is a cross-sectional view of the second mold M2 taken along the XZ plane at the center of the handle portion 6 in the length direction.

As shown in FIG. 14, the upper mold M21 of the second mold M2 accommodates part of the accommodating portions 2M and 4M that accommodate the head portion 2 and the flocked surface 20 side of the neck portion 4 and the gripping piece 31a. As shown in FIG. 15, the housing portion 31aM has a surface 35 for molding the outer peripheral surface of the soft portion 41 on the side of the flocked surface 20, and shaft members 137bM and 137cM for molding the through holes 137b and 137c. . The surface 35 is formed flush with the surface facing the soft portion 41 of the grip piece 31a accommodated in the accommodating portion 31aM.

The lower mold M22 of the second mold M2 includes a housing part 2M, 4M for housing the head part 2 and the neck part 4 on the side of the flocked surface 20, a housing part 31bM for housing the gripping piece 31b, and a gripping piece 31c. A housing portion 31cM for housing the outer peripheral surface of the soft portion 41 opposite to the flocked surface 20 side, and a shaft member 137aM for molding the through hole 137a. The surface 36 is formed flush with the gripping piece 31b accommodated in the accommodating portion 31bM and the surface facing the soft portion 41 of the grasping piece 31c accommodated in the accommodating portion 31cM.

The gripping pieces 31a, 31b, 31c, the surface 35 of the upper mold M21, and the surface 36 of the lower mold M22 form a cavity 41M for molding the soft portion 41.

The shaft members 137bM and 137cM are formed so that their tips are flush with the surfaces of the gripping pieces 31b and 31c facing the cavity 41M. The lengths of the shaft members 137bM and 137cM are such that when the upper mold M21 and the lower mold M22 are clamped, the surface and the tip of the gripping pieces 31b and 31c that are accommodated in the accommodating portions 31bM and 31cM face the cavity 41M. Each is the same length. The shaft member 137aM is formed so that the tip thereof is flush with the surface facing the cavity 41M of the gripping piece 31a. The length of the shaft member 137aM is such that when the upper mold M21 and the lower mold M22 are clamped, the surface facing the cavity 41M of the gripping piece 31a accommodated in the accommodation part 31aM is flush with the tip part. It is.

The shaft members 137aM, 137bM, and 137cM can be directly formed on the second mold M2 (upper mold M21 or lower mold M22) by cutting or the like, but the second mold M2 is easily manufactured due to the ease of the manufacturing process. It is preferable to provide shaft members 137aM, 137bM, and 137cM that fit into the formed holes as separate members.

The hard part 50 is accommodated in the accommodating parts 2M, 4M, the accommodating part 31aM, the accommodating part 31bM, and the accommodating part 31cM inside the upper mold M21 and the lower mold M22. As shown in FIGS. 14 and 15, the grip piece 31a of the hard portion 50 housed in the upper mold M21 and the lower mold M22 is supported by the shaft member 137aM and is held by the upper mold M21 (housing section 31aM). Retained. The gripping pieces 31b and 31c of the hard portion 50 accommodated in the upper mold M21 and the lower mold M22 are supported by the shaft members 137bM and 137cM and held by the lower mold M22 (accommodating sections 31bM and 31cM), respectively.

Thereafter, a melted soft resin is filled in the cavity in the mold in a state where the upper mold M21 and the lower mold M22 accommodating the hard portion 50 are clamped, and after cooling for a predetermined time, the upper mold M21 and the lower mold By releasing from M22, the handle body 10 including the soft portion 41 in which the gripping pieces 31a, 31b, and 31c are disposed around the outer periphery and the through holes 137a, 137b, and 137c are formed is formed.

Next, a hair bundle is implanted in the head portion 2 of the obtained handle body 10. As a method for flocking the hair bundle, the hair bundle is folded in two and a flat wire sandwiched between the two is driven into the flock hole 22 so that the hair bundle is planted, and the lower end of the hair bundle is melted to become the flocked portion. Examples thereof include a heat-sealing method in which the resin is pressed into a resin and fixed, and an in-mold method in which the bottom end of the hair bundle is heated to form a molten lump, and then the molten resin is injected into the mold to mold the flocked portion.

When using the toothbrush 1 having the above-described configuration, the head portion 2, the neck portion 4 and the gripping pieces 31a to 31c constitute the hard portion 50, so that the rigidity during brushing is ensured and the cleaning force is maintained, and the handle When the part 6 is gripped, the gripping pieces 31a, 31b, 31c are elastically deformed and bent, and the elastic restoring force is transmitted to the palm, so that a high fit is imparted. In particular, the gripping pieces 31a, 31b, and 31c in the toothbrush 1 are not restrained because their rear end side ends are separated from each other, so that the elastic restoring force accompanying the bending of the gripping pieces 31a, 31b, and 31c is efficiently increased in the palm of the hand. It is transmitted to.

In addition, when the toothbrush 1 configured as described above is gripped by the handle portion 6, in addition to the elastic deformation of the grip pieces 31a, 31b, 31c, the soft portion 41 is also elastically deformed. Therefore, the elastic restoring forces of the gripping pieces 31a to 31c and the soft portion 41 are combined, so that a high fit can be obtained in the entire handle portion 6. Furthermore, since the toothbrush 1 having the above-described configuration has the through holes 137a, 137b, and 137c formed in the soft portion 41, the soft portion 41 is easily deformed when the handle portion 6 is grasped, and a higher fit is provided. Obtainable. In addition, the toothbrush 1 having the above-described configuration is effective when the gripping pieces 31a, 31b, and 31c are gripped because one end of the through holes 137a, 137b, and 137c is opened facing the gripping pieces 31a, 31b, and 31c. Thus, the soft part 41 can be deformed.

Here, for example, when the rear end sides of the gripping pieces 31a, 31b, and 31c are all connected, there is a space in which the soft portion 41 around which the gripping pieces 31a, 31b, and 31c are arranged is deformed on the rear end side. It will be regulated. On the other hand, in the toothbrush 1 of this embodiment, since the rear end side ends of the gripping pieces 31a, 31b, 31c are separated from each other, the rear end side of the soft portion 41 can be freely deformed without being restricted. Thus, flexibility can be improved and a high fit can be created.

Furthermore, in the toothbrush 1 of this embodiment, since the gripping pieces 31a, 31b, and 31c are arranged around the outside of the soft part 41, the area where the soft part 41 is exposed and touched by the user can be reduced. . In particular, in the toothbrush 1 of the present embodiment, in the cross section orthogonal to the length direction, the outer contour of the soft portion 41 is disposed inside the circle circumscribing the gripping pieces 31a, 31b, 31c. When grasping 31b and 31c, the opportunity for a user to touch the soft part 41 can be reduced. Therefore, in the toothbrush 1 of this embodiment, it can suppress that a usability | use_condition falls by the stickiness resulting from the bloom / bleed-out which generate | occur | produces with a time-dependent change of a soft material.

In addition, in the toothbrush 1 of the present embodiment, the gripping pieces 31a, 31b, and 31c are arranged at positions that do not overlap each other in the direction orthogonal to the flocked surface 20, so that some of the mold parts are in the opening / closing direction of the mold. As described above, it is possible to form the handle body 10 with only a mold that opens and closes in the Z direction without providing a mechanism for moving in the intersecting direction, which can contribute to a reduction in manufacturing cost.

Moreover, in the manufacturing method of the toothbrush 1 of this embodiment, since the gripping pieces 31a, 31b, and 31c are supported by the shaft members 137aM, 137bM, and 137cM and held in the accommodating portions 31aM, 31bM, and 31cM, the gripping pieces 31a, There is no need to separately provide an external device for accommodating 31b and 31c in the accommodating portions 31aM, 31bM, and 31cM, and the manufacturing cost can be reduced.

As described above, the preferred embodiments according to the present invention have been described with reference to the accompanying drawings, but it goes without saying that the present invention is not limited to such examples. Various shapes, combinations, and the like of the constituent members shown in the above-described examples are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

For example, in the first to fourth embodiments, the configuration in which the rear end side end portions of the gripping pieces 31a to 31c are provided separately from each other is illustrated, but the present invention is not limited to this configuration, and at least one It is sufficient that the two gripping pieces are separated. As described above, the grip piece whose rear end side portion is separated from other grip pieces is elastically deformed and bent when the handle portion 6 is grasped, and its elastic restoring force is transmitted to the palm. Compared with the case where the rear end side ends of the gripping pieces are connected, a high fit is imparted.

In the first to fourth embodiments, the configuration having the three gripping pieces 31a to 31c is illustrated. However, the number of the gripping pieces may be two or more. As described above, from the viewpoint of manufacturing cost, it is preferable that the number of gripping pieces is small, but from the viewpoint of feeling of use including stickiness, for example, it is preferable to arrange three or more and five or less gripping pieces. In particular, it is more preferable to dispose the three gripping pieces shown in the above embodiment from the viewpoint of achieving both manufacturing cost and usability.

In the first to third embodiments, the configuration in which the hard portion 50 and the soft portion 41 are integrally formed by using the second mold M2 containing the hard portion 50 is exemplified. For example, the structure is such that the soft portion 41 is formed separately in a separate process, and the soft portion 41 is fixed at a position where the gripping pieces 31a to 31c are arranged around the outside using an adhesive or the like. There may be.

Moreover, in the said 4th Embodiment, although the structure which shape | molds the hard part 50 and the soft part 41 integrally was illustrated using the 2nd metal mold | die M2 which accommodated the hard part 50, it is limited to this structure. For example, the structure may be such that the soft part 41 is formed separately in a separate process and the soft part 41 is fixed at a position where the gripping pieces 31a to 31c are arranged around the outside using an adhesive or the like. Good. Also in this case, through holes 137a, 137b, and 137c are provided in the soft portion 41, one end of each of the through holes 137a, 137b, and 137c is opened facing the gripping pieces 31a, 31b, and 31c, and the other end is exposed to the outside. It is preferable to open them.

Moreover, in the said 4th Embodiment, although the cross-sectional shape of the through- holes 137a, 137b, 137c was illustrated circularly, it is not limited to this structure, For example, an ellipse shape, an ellipse shape, a polygon shape It is possible to appropriately select a shape having excellent design properties such as a rectangular shape or a triangular shape, or a star shape. Furthermore, the number of through- holes 137a, 137b, and 137c shown in the above embodiment is an example, and can be suitably set to an arbitrary number from the range of preferably 3 or more and 10 or less.

The present invention can be applied to toothbrushes and toothbrush manufacturing methods.

DESCRIPTION OF SYMBOLS 1 ... Toothbrush, 2 ... Head part, 4 ... Neck part, 6 ... Handle part, 20 ... Flocking surface, 31, 31a, 31b, 31c ... Grasping piece, 37a, 37b, 37c ... Shaft part, 41 ... Soft part, 50: Hard part, 137a: Through hole (first through hole)

Claims (20)

1. A head portion having a flocked surface on the distal end side in the length direction;
   A handle portion arranged on the rear end side from the head portion;
   A neck portion disposed between the flocked surface and the handle portion;
   The handle portion is formed of a hard resin and branches from a boundary with the neck portion and extends to the rear end side, and a plurality of gripping pieces,
   A soft portion formed in a long shape with a soft resin, extending to the rear end side, and having a plurality of gripping pieces arranged around the outside in a cross section orthogonal to the length direction,
   The toothbrush characterized in that at least one of the grip pieces is provided with an end on the rear end side separated from the other grip pieces.
2. The toothbrush according to claim 1, wherein the plurality of gripping pieces are provided such that end portions on the rear end side are separated from each other.
3. The toothbrush according to claim 2, wherein the plurality of grip pieces are arranged at positions that do not overlap each other in a direction orthogonal to the flocked surface.
4. The toothbrush according to claim 3, further comprising an axial portion extending in a direction orthogonal to the flocked surface from the gripping piece.
5. The toothbrush according to claim 4, wherein the tip of the shaft-like portion is disposed flush with the outer peripheral surface of the soft portion or at a position recessed from the outer peripheral surface of the soft portion.
6. The toothbrush according to claim 1, wherein three or more and five or less gripping pieces are arranged.
7. The toothbrush according to claim 6, wherein three gripping pieces are arranged.
8. The toothbrush according to any one of claims 1 to 7, wherein the soft portion is formed integrally with the gripping piece.
9. The toothbrush according to any one of claims 1 to 7, wherein the soft part is fixed to the grip piece with an adhesive.
10. A head portion having a flocked surface on the distal end side in the length direction;
    A handle portion arranged on the rear end side from the head portion;
    A neck portion disposed between the flocked surface and the handle portion;
    The handle portion is formed of a hard resin and branches from a boundary with the neck portion and extends to the rear end side, and a plurality of gripping pieces,
    A soft portion that is formed of a soft resin and extends in a long shape from the boundary with the neck portion toward the rear end side, and the plurality of gripping pieces are arranged around the outside in a cross section orthogonal to the length direction. ,
    The plurality of gripping pieces are arranged at positions that do not overlap each other in a direction orthogonal to the flocked surface, and at least one end on the rear end side is provided separately from the other gripping pieces. ,
    The soft part has a through hole extending in a direction orthogonal to the flocked surface,
    A toothbrush characterized in that one end of the through-hole opens toward the grip piece, and the other end is exposed and opened to the outside.
11. The toothbrush according to claim 10, wherein a plurality of the through holes are arranged at positions facing each of the plurality of gripping pieces.
12. The toothbrush according to claim 11, wherein a plurality of the through holes are arranged along the gripping piece for each of the plurality of gripping pieces.
13. The toothbrush according to claim 12, wherein the through holes are arranged in a number of 3 or more and 10 or less for each of the plurality of gripping pieces.
14. 12. The through hole includes a first through hole that is exposed and opened on one side in a direction orthogonal to the flocked surface, and a second through hole that is exposed and opened on the other side. The toothbrush as described in any one of thru | or 13.
15. The toothbrush according to any one of claims 10 to 14, wherein the plurality of gripping pieces are provided such that end portions on the rear end side are separated from each other.
16. The toothbrush according to any one of claims 10 to 15, wherein three or more and five or less gripping pieces are arranged.
17. The toothbrush according to claim 16, wherein three gripping pieces are arranged.
18. The cross section orthogonal to the length direction, the outer contour of the soft portion is arranged inside a circle circumscribing the plurality of gripping pieces, 18. The toothbrush described.
19. A toothbrush having a head portion having a flocked surface on the front end side in the length direction, a handle portion disposed on the rear end side from the head portion, and a neck portion disposed between the flocked surface and the handle portion. A manufacturing method of
    It constitutes a part of the handle portion, is branched from the boundary with the neck portion, extends to the rear end side, is arranged at a position that does not overlap with each other in a direction perpendicular to the flocked surface, and at least one of the rear portions A first step of forming a plurality of gripping pieces whose end parts on the end side are separated from other gripping pieces together with the head part and the neck part as a hard part using a first resin with a hard resin; ,
    A part of the handle portion is formed, extends in a long shape from the boundary with the neck portion to the rear end side, and the plurality of gripping pieces are arranged around the outside in a cross section orthogonal to the length direction. A second step of forming the soft part integrally with the hard part with a soft resin using a second mold that houses the hard part therein,
    In the second step, a holding part extending toward the other side in a direction orthogonal to the flocked surface from a mold located on one side of the second mold in a direction orthogonal to the flocked surface is moved to the other side. A method for manufacturing a toothbrush, wherein the gripping piece is held in a receiving part of a mold located.
20. After the second step, the soft portion is formed with a through hole having one end facing the gripping piece and opened to the outside and the other end exposed to the outside by the holding portion. The method for manufacturing a toothbrush according to claim 19.

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