TWI861310B - toothbrush - Google Patents

Abstract

The purpose of the present invention is to provide a toothbrush with excellent insertion performance, operability and durability. The maximum thickness of the head (5) is greater than 2.0 mm and less than 4 mm. When the brush body (2) is observed from the side, the hair-implanted surface side has: a first straight line area (S1) extending continuously in a straight line from the hair-implanted surface (5a); a first curved area (E1) having a center of curvature on the hair-implanted surface side and extending in an arc shape from a first inflection point (P1) to the rear end side; and a second curved area (E2) having a center of curvature on the back side opposite to the hair-implanted surface side and extending from the rear end of the first curved area to the rear end side. The second inflection point (P2) extends in an arc shape toward the rear end, and the inclination angle of the neck represented by the angle of intersection of a straight line passing through the rear end edge located at the rearmost side when viewed from the side and the second inflection point and a virtual line (50) is greater than 8° and less than 25°, and the virtual line (50) passes through the rear end edge (Q1) of the hair implantation hole located at the rearmost side among the multiple hair implantation holes and the rear end edge (Q2) of the second hair implantation hole located at the rear end.

Description

toothbrush

The present invention relates to a toothbrush. This application claims priority based on Japanese Patent Application No. 2019-237178 filed in Japan on December 26, 2019, and the contents thereof are cited in this application.

For the prevention of caries and periodontal disease, it is important to remove dental plaque in the oral cavity by brushing with a toothbrush. As a toothbrush that can reach the deep part of the molar (the throat side of the molar) that is difficult to reach with a normal toothbrush, for example, a toothbrush is commercially available that has a tuft portion provided at the implantation portion on the front end side of the head so that the tips of the bristles can easily reach the molar.

In addition, Patent Document 1 discloses a toothbrush having a neck, wherein the neck has curved surfaces formed on both the hair implantation side and the back side, with the center of the arc located on the hair implantation side and the hair implantation side showing a concave arc contour when viewed from the side. The toothbrush disclosed in Patent Document 1 can improve the insertability or operability of the last molar by having the curved surface. [Prior Art Document] [Patent Document]

[Patent Document 1] International Publication No. 2018/079114

[Problem to be solved by the invention] However, in the commercially available toothbrushes in which the bristle bundle is provided in the bristle implantation portion on the front end side, since only the bristle bundle comes into contact with the tooth surface when brushing, there is a problem that it is difficult to brush a large area of the tooth surface.

The toothbrush disclosed in Patent Document 1 is an S-shaped toothbrush in which the neck of the back side is temporarily curved toward the back side near the boundary between the head and the neck and then curved toward the bristle-planted side. Therefore, when the toothbrush is inserted deep into the molars in the oral cavity, the back side of the neck may contact the cheeks, thereby reducing the usability. A toothbrush with a better usability is required. In addition, if the neck extending from the head is thick, the lips need to be opened wide when inserting the toothbrush into the oral cavity, which reduces the operability.

The present invention is made in consideration of the above aspects, and aims to provide a toothbrush with excellent insertion and operability. [Means for solving the problem]

According to a first aspect of the present invention, a toothbrush can be provided, the toothbrush comprising a brush body, the brush body being provided with a handle along a long axis, a neck extending from the front end of the handle, and a head located at the front end of the neck, hair bundles being planted in a plurality of hair planting holes formed on a hair planting surface of the head, and the toothbrush being characterized in that the brush body has a shape in which the thickness of the neck continuously increases from the head toward the handle, and the maximum thickness of the head is not less than 2.0 mm and not more than 4.0 mm. mm, the side of the implanted hair surface when the brush body is observed from the side has: a first straight line area, extending continuously from the implanted hair surface to the rear end side in a straight line shape; a first curved area, having a center of curvature on the side of the implanted hair surface, extending in an arc shape from a first inflection point at the rear end of the first straight line area to the rear end side; and a second curved area, having a center of curvature on the back side opposite to the implanted hair surface side, extending from the rear end of the first curved area to the rear end side. The second inflection point at the end extends in an arc shape toward the rear end side, and the inclination angle of the neck represented by the angle of intersection of a straight line passing through the rear end side edge of the hair implantation hole located at the rearmost end side when viewed from the side and a virtual line passing through the rear end side edge of the hair implantation hole located at the rearmost end side when viewed from the side and the rear end side edge of the second hair implantation hole located at the rear end side.

In addition, in one embodiment of the toothbrush of the present invention, the feature is that, on the back side when viewed from the side, there is: a second straight line area, extending continuously in a straight line from the back side of the head to the rear end side; and a third curved line area, having a center of curvature on the hair-implanted surface side, extending in an arc shape from a third inflection point located at the rear end of the second straight line area to the rear end side.

In addition, in one embodiment of the toothbrush of the present invention, the back side in the side view has a fourth curved area, the fourth curved area has a center of curvature on the back side, and extends in an arc shape from a fourth inflection point located at the rear end of the third curved area to the rear end side.

In addition, in the toothbrush according to one aspect of the present invention, the minimum thickness of the neck portion is 3.0 mm to 4.0 mm, and the length in the major axis direction is 5 mm or more.

In addition, in the toothbrush of one aspect of the present invention, the cross-sectional shape of the boundary between the neck and the handle is an elliptical shape.

In addition, in the toothbrush according to one aspect of the present invention, the length of the neck in the direction of the major axis is greater than or equal to 25 mm and less than or equal to 45 mm.

In addition, in the toothbrush of one embodiment of the present invention, the position in the long axis direction where the distance between the handle on the hair implantation surface side and the virtual line is longest in the side view is located closer to the front end side than the center in the long axis direction of the handle.

In addition, in a toothbrush of one embodiment of the present invention, the front end side of the head is inclined at an angle of 5° or more and 15° or less relative to the virtual line toward the hair implantation surface side when viewed from the side. [Effect of the invention]

The present invention can provide a toothbrush with excellent insertion performance and operability.

The following describes the implementation of the toothbrush of the present invention with reference to Figures 1 to 4. Furthermore, the following implementation is a method of representing the present invention, and does not limit the present invention, and can be arbitrarily changed within the scope of the technical concept of the present invention. In addition, in the following figures, in order to facilitate the understanding of each structure, the actual structure is different from the scale or quantity in each structure.

In the following description, the side of the head 5 described later on which the hair-implanted surface 5a is provided is referred to as the front side of the toothbrush 1, and the side opposite to the side facing the hair-implanted surface 5a of the head 5 is referred to as the back side of the toothbrush 1. In addition, the direction parallel to the hair-implanted surface 5a and perpendicular to the length direction of the brush body 2 is referred to as the width direction of the toothbrush 1, and the direction perpendicular to the hair-implanted surface 5a is referred to as the thickness direction of the toothbrush 1. In addition, the side on which the head 5 is provided is referred to as the front end side, and the side on which the handle 3 is provided is referred to as the rear end side.

Fig. 1 is a side view showing the structure of a toothbrush 1. Fig. 2 is a front view of the toothbrush 1 as viewed from the side of the implanted bristle surface 5a. Fig. 3 is an enlarged front view of the head 5. Fig. 4 is an enlarged side view of the head 5. In Figs. 2 to 4, the brush 40 is omitted.

As shown in Fig. 1 and Fig. 2, the toothbrush 1 of the present embodiment includes a brush body 2 and a brush 40. The brush body 2 includes a resin molded body formed in a long strip shape as a whole.

The brush body 2 is provided with a handle 3, a neck 4 extending from the front end of the handle 3, and a head 5 provided at the front end of the neck 4 along the long axis direction. The so-called long axis direction refers to the direction in which the virtual line 50 described later extends. In the toothbrush 1, the oral cavity can be cleaned by a plurality of hair bundles 41 provided on the hair implantation surfaces 5a to 5d of the head 5.

The resin constituting the brush body 2 is preferably polypropylene (PP) resin, polyacetal (POM) resin, polybutylene terephthalate (PBT) resin, polyethylene terephthalate (PET) resin, etc. Among them, it is preferable to use PP resin which has a good balance between stress dispersion and strength in the present invention.

The flexural modulus of the resin constituting the brush body 2 (Japanese Industrial Standards (JIS) K 7171) is preferably 1000 MPa to 2800 MPa, more preferably 1200 MPa to 2500 MPa, and even more preferably 1500 MPa to 2000 MPa.

(Shape of the front side of the brush body) Regarding the toothbrush 1 of the present embodiment, when the brush body 2 is observed from the side, on the front side of the brush body 2, from the rear end side of the head 5 (the "rear end side of the head 5" will be described later) toward the handle 3 side, there are: a first straight line area S1 extending continuously from the hair-planting surface 5a of the head 5 to the rear end side in a straight line shape; a first curved area E1 having a curvature center on the front side, extending in an arc shape from a first inflection point P1 located at the rear end of the first straight line area S1 to the rear end side; and a second curved area E2 having a curvature center on the back side, extending in an arc shape from a second inflection point P2 located at the rear end of the first curved area E1 to the rear end side.

The first inflection point P1 is located at the head 5. The second inflection point P2 forms a boundary between the neck 4 and the handle 3. That is, the handle 3 is located further back than the second inflection point P2. Details of the second inflection point P2 forming the boundary between the neck 4 and the handle 3 will be described later.

(Shape of the back side of the brush body) Regarding the toothbrush 1 of the present embodiment, when the brush body 2 is viewed from the side, on the back side of the brush body 2, from the rear end side of the head 5 toward the handle 3 side, there are: a second substantially straight line area S2 extending continuously from the back side of the head 5 to the rear end side in a straight line shape; a third curved area E3 having a curvature center on the front side, extending in an arc shape from a third inflection point P3 located at the rear end of the second straight line area S2 to the rear end side; and a fourth curved area E4 having a curvature center on the back side, extending in an arc shape from a fourth inflection point P4 located at the rear end of the third curved area E3 to the rear end side. The third inflection point P3 is located at the head 5.

The fourth curved area E4 is a portion that the fingers touch when holding the handle 3. The fourth curved area E4 is an arc having a center of curvature on the back side and is curved into a concave shape on the back side, so that the fingers fit into the handle 3, thereby improving the ease of holding and the ease of brushing the molars.

If the radius of curvature of the first curved area E1 is set to R1, the radius of curvature of the second curved area E2 is set to R2, the radius of curvature of the third curved area E3 is set to R3, and the radius of curvature of the fourth curved area E4 is set to R4, then it is preferable to satisfy the relationship of R1＜R3, R2＜R4. As the radius of curvature R1, it is preferably greater than 60 mm and less than 150 mm. As the radius of curvature R2, it is preferably greater than 50 mm and less than 100 mm. As the radius of curvature R3, it is preferably greater than 80 mm and less than 400 mm. As the radius of curvature R4, it is preferably greater than 70 mm and less than 200 mm.

As the radius of curvature R1, it is preferably 50 mm to 250 mm, more preferably 60 mm to 200 mm, and more preferably 60 mm to 150 mm. As the radius of curvature R2, it is preferably 50 mm to 250 mm, more preferably 60 mm to 200 mm, and more preferably 50 mm to 100 mm. As the radius of curvature R3, it is preferably 50 mm to 600 mm, more preferably 60 mm to 500 mm, and more preferably 80 mm to 400 mm. As the radius of curvature R4, it is preferably 50 mm to 400 mm, more preferably 60 mm to 300 mm, and more preferably 70 mm to 200 mm.

The cross-sectional shape of the boundary (P2) between the neck 4 and the handle 3 is preferably a substantially quadrilateral, a substantially polygonal, a perfect circle, an ellipse, and more preferably an ellipse. With such a shape, the ease of changing hands is reduced, and the operability when brushing the molars is reduced.

The cross-sectional area at the boundary between the neck 4 and the handle 3 is preferably 20 mm ² to 80 mm ² , more preferably 25 mm ² to 55 mm ² , and even more preferably 25 mm ² to 45 mm ² or less. By being within the above range, durability can be ensured.

(Head) The head 5 is a part that brushes the inside of the oral cavity with a plurality of bristle bundles 41, and has a shape that is formed into a roughly rectangular parallelepiped with rounded corners. In the present embodiment of FIG. 1 and FIG. 4, the head 5 has: a flat plate portion 51, which is located on the rear end side and has a bristle-implanted surface 5a as a reference surface on the front side; and an inclined plate portion 52, which is located on the front end side of the flat plate portion 51. The bristle-implanted surface 5a of the flat plate portion 51 and the back surface on the opposite side thereof are formed as mutually flat surfaces. When viewed from the side, the flat plate portion 51 is roughly parallel to the virtual line 50 described later. In the present embodiment of FIG. 1 and FIG. 4, the inclined plate portion 52 is provided, but it is also possible to have only the flat plate portion 51 without the inclined plate portion 52.

In the case of having an inclined plate portion 52, it is preferably inclined toward the front side (i.e., the hair-implanted side) as it moves toward the front end side. The angle at which the inclined plate portion 52 is inclined relative to the flat plate portion 51 (the virtual line 50 when viewed from the side) is preferably an angle of 5° or more and 15° or less. In the present embodiment of FIG. 1 and FIG. 4, the angle at which the inclined plate portion 52 is inclined relative to the flat plate portion 51 is 10° as an example.

By tilting the tilt plate portion 52 relative to the flat plate portion 51, the hair length of the hair bundle 41 at the front end of the head 5 becomes shorter, and the hair bundle is less likely to bend than the hair bundle 41 at the rear end of the head 5, thereby improving the hair rigidity, thereby obtaining a high-definition cleaning feeling of the molars. By tilting the tilt plate portion 52 at an angle of 5° to 15°, the cleaning feeling of the molars is excellent.

As shown in Fig. 3 and Fig. 4, the inclined plate portion 52 has three hair-implanted surfaces 5b to 5d of different heights. Each hair-implanted surface 5b to 5d is parallel to the hair-implanted surface 5a. The hair-implanted surfaces 5b to 5d gradually become higher toward the front end side according to the inclination of the inclined plate portion 52. In addition, as shown in Fig. 1, the hair length of the hair bundle 41 implanted on the hair-implanted surface 5b to 5d is the same height as the hair length of the hair bundle 41 implanted on the hair-implanted surface 5a. Furthermore, the hair length of the hair bundle 41 implanted on the hair-implanted surface 5b to 5d may be lower or higher than the hair length of the hair bundle 41 implanted on the hair-implanted surface 5a.

On the hair implantation surfaces 5a to 5d, a plurality of hair implantation holes 6 of the same diameter are arranged in a staggered manner. The hair implantation holes 6 are arranged at positions where adjacent rows in the long axis direction are staggered by half a pitch. The hair bundles are implanted in each hair implantation hole 6 by bundling a plurality of bristles (filaments) and folding them in half, sandwiching a metal anti-stripping tool (not shown) called a flat wire in the middle and driving it into the hair implantation hole 6.

Furthermore, the hair implantation holes 6 are not limited to a structure in which a plurality of holes are arranged in a grid pattern, but may also be a structure in which a plurality of holes are arranged in a staggered pattern. In addition, the inner diameter of the hair implantation holes 6 is related to the number of hair bundles to be implanted, and thus affects the hardness or feel of the hair bundles. Although the feel of use can be adjusted to a certain extent according to the thickness or length of the hair bundles used for hair implantation, it is generally preferred to be in the range of 1.0 mm to 3.0 mm.

The hair implantation holes 6 provided on the hair implantation surface 5a are formed in the normal direction of the hair implantation surface 5a. The hair implantation holes 6 provided on the hair implantation surfaces 5b to 5d are formed to be inclined by 5° in the direction from the opening toward the rear end side with respect to the normal direction of the hair implantation surfaces 5b to 5d.

When the hair bundle 41 is inserted into the hair implantation hole in a folded state using a flat line for hair implantation, the hair implantation surface 5a to the hair implantation surface 5d are arranged orthogonally to the insertion direction, so that the hair can be implanted stably. In addition, when the hair implantation hole 6 is greatly inclined relative to the insertion direction (inclined in a direction orthogonal to the inclined plate portion 52, etc.), the insertion of the hair bundle 41 may become unstable, but the hair implantation hole 6 arranged on the hair implantation surface 5b to the hair implantation surface 5d is inclined at a degree of 5° in the direction from the opening portion toward the rear end side, so the hair bundle 41 can be inserted without any obstacles.

The material of the bristles of the hair bundle 41 is not particularly limited, but examples thereof include synthetic resin materials such as polyamide (e.g., 6-12 nylon, 6-10 nylon), polyester (e.g., polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate), polyolefin (e.g., polypropylene), and elastomer (e.g., olefin, styrene). In addition, these resin materials can be used in combination, for example, different resin materials can be used in the core and sheath as in a core-sheath structure.

In addition, as the bristles constituting the hair bundle 41, for example, toothbrush bristles whose diameter gradually decreases toward the hair tip and whose hair tip is sharpened (taper hair), toothbrush bristles whose diameter is roughly the same from the hair implantation surface 5a toward the hair tip (straight hair), etc. can be listed. As straight hair, those whose hair tip is a plane roughly parallel to the hair implantation surface 5a, or those whose hair tip is kneaded into a hemispherical shape can be listed. The bristles constituting the hair bundle 41 implanted on the hair implantation surface 5b to the hair implantation surface 5d are preferably tapered hair or straight hair. The bristles constituting the hair bundle 41 implanted on the hair implantation surface 5a are preferably tapered hair or straight hair. The front end of any of the hair implantation surfaces 5a to the hair implantation surface 5d can be sheared by hair cutting.

The cross-sectional shape of the bristles is usually circular, but is not limited to this shape, and can be any shape such as an ellipse, a triangle, a quadrilateral, a hexagon, a star, a three-leaf clover, a four-leaf clover, etc.

The hair length of the hair bundle 41 is preferably 8 mm to 13 mm for adult use and 6 mm to 9 mm for children from the hair planting surface 5a of the head 5. In terms of the usability or the feeling of use in the oral cavity, the thickness (maximum diameter) of the bristles is preferably 0.12 mm to 0.26 mm. In addition, considering the feeling of use, the brushing feeling, the cleaning effect, the durability, etc., a plurality of bristles of different thicknesses can be used in any combination.

As a method for implanting the bristle bundle 41, in addition to the flat line implantation method of folding the bristle bundle in half, sandwiching a flat line in the middle and implanting it in the implantation hole 6, the following methods can also be used: a heat welding method of pressing the lower end of the bristle bundle into the molten resin that becomes the head 5 and fixing it, or an in-mold method of heating the lower end of the bristle bundle to form a molten block, filling the molten resin into the cavity of the mold and forming it as a whole with the head 5, etc.

The head 5 has a substantially quadrilateral flat plate shape with four tops cut by curved lines when viewed from above. In the present embodiment, the boundary O between the head 5 and the neck 4 is the end point of the curve forming the cut angle near the neck 4 in the top view of the head 5, that is, the position where the bending direction of the curve forming the cut angle changes. Therefore, the boundary O between the head 5 and the neck 4 is the position where the curve or straight line at the two edges of the head 5 forming the cut angle near the neck 4 in the top view changes from the narrowed width to the widened curve.

Furthermore, the shape of the head 5 is not particularly limited as long as it is a shape or size that is easy to brush the inside of the oral cavity. For example, it can be a shape in which the width gradually narrows from the base end side toward the front end side. In addition, the head 5 can be a conical shape in which the thickness gradually becomes thinner from the base end side toward the front end side, or it can be a circular shape with a raised central portion on the back side of the head 5.

The thickness of the head 5 is preferably 2 mm or more and less than 4 mm, and more preferably 2.5 mm to 3.5 mm. Furthermore, when the thickness of the head 5 is not constant, the thickness of the head 5 is defined as the maximum thickness of the head 5. When the thickness of the head 5 is less than 2 mm, the durability may be reduced. When the thickness of the head 5 is 4 mm or more, the insertability or operability into the molar may be reduced. By setting the thickness of the head 5 to 2 mm or more and less than 4 mm, the insertability or operability into the molar can be improved without reducing the durability.

(Neck) The neck 4 is a portion connecting the handle 3 and the head 5. In this embodiment, the outer shape of the neck 4 and the handle 3 when viewed from above and from the side is a shape formed by connecting a plurality of gentle curves from the boundary O between the head 5 and the neck 4 toward the handle 3 side. Moreover, when viewed from the side, the position where the bending direction of the gentle curve is reversed is used as the boundary between the neck 4 and the handle 3. That is, when viewed from the side in FIG. 1, the position where the center of curvature of the first straight line area S1 having the center of curvature on the front side starts to change from the boundary O toward the handle 3 side and toward the back side (the second inflection point P2) is used as the boundary between the neck 4 and the handle 3.

The length of the neck 4 in the long axis direction is defined as the shortest distance between the position of the inflection point P2 and the boundary O when viewed from the side. The length of the neck 4 is preferably 25 mm to 45 mm, and more preferably 25 mm to 40 mm. By setting the length of the neck 4 within the above range, the insertability into the molar and the operability when cleaning the molar can be improved.

The cross-sectional shape of the neck 4 is preferably a roughly quadrilateral, roughly polygonal, perfectly circular, or elliptical, and is more preferably an elliptical shape. More preferably, it is an elliptical shape with the major diameter in the thickness direction. The thickness of the neck 4 increases continuously from the front end side toward the rear end side. By increasing the thickness of the neck 4 continuously, the strength of the neck 4 can be increased compared to the case where the thickness of the neck 4 is constant. In addition, the thickness of the neck 4 increases continuously from the front end side toward the rear end side, so that the lips will not open wider when inserted into the oral cavity, and operability in the oral cavity can be ensured. In addition, since the position where the stress applied to the neck 4 during brushing is concentrated is set on the side of the head 5, the distance for dispersing the stress in the direction of the handle 3 described later can be fully ensured, thereby suppressing excessive bending of the neck 4.

The minimum thickness of the neck is preferably 3.0 mm to 4.0 mm, more preferably 3.0 mm to 3.6 mm. The minimum width of the neck is preferably 3.0 mm to 4.5 mm, more preferably 3.5 mm to 4.2 mm. The minimum diameter of the neck 4 is preferably 3.0 mm to 4.0 mm, more preferably 3.0 mm to 3.6 mm. When the minimum thickness of the neck, the minimum width of the neck, and the minimum diameter of the neck 4 are less than 3.0 mm, the neck 4 is easily bent and operability may be reduced. When the minimum thickness of the neck, the minimum width of the neck, and the minimum diameter of the neck 4 exceed 4.0 mm, operability in the oral cavity may be reduced. By setting the minimum thickness of the neck, the minimum width of the neck, and the minimum diameter of the neck 4 to 3.0 mm or more and 4.0 mm or less, operability can be ensured. In addition, the length of the minimum thickness of the neck is preferably 5 mm or more, more preferably 6 mm or more, and further preferably 7 mm or more. The length of the minimum width of the neck is preferably 5 mm or more, more preferably 6 mm or more, and further preferably 7 mm or more. The length of the minimum diameter of the neck is preferably 5 mm or more, more preferably 6 mm or more, and further preferably 7 mm or more. By being within the above range, the insertability and operability into the deep part of the molar can be improved.

As described above, since the first curved area E1 forming the front side of the neck 4 when viewed from the side and the third curved area E3 forming the back side of the neck 4 when viewed from the side are both arc-shaped with the center of curvature on the front side, they follow the curve of the tooth row, thereby improving the insertability when brushing the cheek side of the molars.

The tilt angle θ of the neck 4 is represented by the angle of intersection of a straight line passing through the rear edge of the hair-implanting hole 6 located at the rearmost side when viewed from the side and the second inflection point P2 and the virtual line 50 shown in FIG1. The virtual line 50 is a straight line passing through the rear edge Q1 of the hair-implanting hole 6 located at the rearmost side when viewed from the side and the rear edge Q2 of the second hair-implanting hole 6 located at the rearmost side. Q1 and Q2 are parallel to the hair-implanting surface at the rearmost side of the head in a general toothbrush. As the tilt angle of the neck 4, it is preferably greater than 8° and less than 25°.

When the tilt angle of the neck 4 is less than 8°, the lips need to be widely opened laterally when brushing the cheek side of the molars, and the insertion and operability may be reduced. When the tilt angle of the neck 4 exceeds 25°, the wrist needs to be bent greatly when changing the brushing position, so the operability when brushing the molars may be reduced. By setting the tilt angle of the neck 4 to 8° or more and 25° or less, the insertion and operability when brushing the cheek side of the molars and the operability when changing the brushing position can be ensured.

The shortest distance between the second inflection point P2 and the virtual line 50 when viewed from the side is preferably 5 mm or more and 15 mm or less, and more preferably 8 mm or more and 12 mm or less. This ensures an S-shaped shape, and improves oral insertion and usability. The shortest distance between the "back side P2'" facing the second inflection point P2 when viewed from the side and the virtual line 50 is preferably 1 mm or more and 3 mm or less, and more preferably 1.5 mm or more and 3 mm or less. This ensures an S-shaped shape, and improves oral insertion and usability.

As described above, the toothbrush disclosed in Patent Document 1 is an S-shaped toothbrush in which the shape of the neck on the back side is temporarily curved toward the back side near the boundary between the head and the neck and then curved toward the hair-planting side. Therefore, when inserted into the oral cavity, the back side of the neck contacts the cheek and may reduce the usability. On the other hand, in this embodiment, as shown in FIG. 1, the shape of the back side of the head and the neck when viewed from the side is curved toward the front side from the third inflection point, forming a third curve area E3 with a curvature center on the front side. That is, there is no shape that temporarily curves toward the back side near the boundary between the head and the neck. Therefore, when inserted into the oral cavity, the contact between the back side of the neck and the cheek can be reduced, thereby improving the usability. Furthermore, by reducing the thickness of the head 5 to 2 mm to 4 mm, and reducing the thickness, width, and diameter of the neck to 3.0 mm to 4.5 mm, and setting the length in the long axis direction to more than 5 mm, the insertion, usability, and operability can be further improved. In addition, even if the length of the neck 4 is shortened to 25 mm to 45 mm, the first straight line area S1, the first curved area E1 having the center of curvature on the front side, and the second curved area E2 having the center of curvature on the back side are connected by a gentle curve using the inflection point P1 and the inflection point P2, thereby further improving the usability and operability.

(Handle) The handle 3 is a portion held by the user and is formed in a long column shape. In order to ensure a length sufficient for holding the handle 3 for use, it is preferred that the length from the boundary O to the rear end of the handle 3 when viewed from above be set to 100 mm to 200 mm.

In this embodiment, the handle 3 has a shape when observing the brush body 2 from the side: the thickness continuously increases from its front end side (the second inflection point P2 side) toward the rear end side (the distance between the second curve area E2 and the fourth curve area E4), and after reaching the maximum thickness, the thickness decreases toward the rear end side.

Furthermore, when there are a plurality of locations with the largest thickness in the shank 3, the location closest to the neck 4 is uniquely defined as the location with the largest thickness in the shank 3. In FIG1 , the location with the largest thickness in the shank 3 is shank 3Amax.

The position P11 in the long axis direction where the distance between the front side surface of the shank 3 and the virtual line 50 is the longest when viewed from the side (that is, the position P11 is at the maximum height relative to the virtual line 50 when viewed from the side) is located at the shank 3A which is closer to the front end side than the center of the long axis direction of the shank 3. That is, the position P11 is located closer to the front end side of the head than the center position of the length of the shank 3 in the long axis direction. With the position P11 as the boundary when viewed from the side, the front end side of the head is set as the shank 3A, and the rear end side of the shank is set as the shank 3B. In the shank 3, in order to perform fine control of the hair tip, it is preferable that the position of the front side surface when viewed from the side is close to the front end of the hair bundle 41.

Here, the distance between the position P11 and the virtual line 50 is longer than the front end of the hair bundle 41. On the other hand, the distance between the second inflection point P2, which is the front end of the handle 3 (handle 3A), and the virtual line 50 is shorter than the front end of the hair bundle 41. In addition, the distance between the rear end of the handle 3 (handle 3B) and the virtual line 50 is longer than the front end of the hair bundle 41. That is, with respect to the front side surface of the handle 3, the change in the position of the region between the position P11 and the second inflection point P2 relative to the front end of the hair bundle 41 is large, while the change in the position of the region between the position P11 and the rear end relative to the front end of the hair bundle 41 is small, which is suitable for fine control of the hair tip. Therefore, by locating the position P11 in the handle 3A, the area suitable for fine control of the hair tips becomes longer, and the molars can be easily brushed even when the rear end side of the handle 3 is held.

The shortest distance between the position P11 of the front side surface of the handle 3 in side view and the virtual line 50 is preferably 20 mm or more and 32 mm or less, and more preferably 22 mm or more and 26 mm or less. When the distance between the position P11 and the virtual line 50 is less than 20 mm, or when the distance between the position P11 and the virtual line 50 exceeds 32 mm, at the rear end of the handle 3, the position of the front side surface in side view is greatly deviated from the front end of the hair bundle 41, and the controllability of the hair tip may be reduced. The shortest distance between the position P11 of the front side surface of the handle 3 in side view and the intersection of the back side surface extending in a direction perpendicular to the virtual line 50 and facing the position P11, i.e., the position p11', and the virtual line 50 is preferably 8 mm or more and 12 mm or less, and more preferably 10 mm or more and 12 mm or less. In this way, the S-shape can be ensured, and the insertability and usability in the oral cavity can be improved.

In addition, the back side of the handle 3 is preferably a shape that does not intersect with the virtual line 50 until the end of the handle. The shortest distance between the back side surface of the handle 3B on the end side of the handle and the virtual line 50 is preferably 8 mm or more and 20 mm or less, preferably 10 mm or more and 15 mm or less. The shortest distance between the end of the handle and the virtual line 50 when viewed from the side is preferably 8 mm or more and 20 mm or less, more preferably 12 mm or more and 18 mm or less. Thereby, the S-shape can be ensured, and the insertability and usability in the oral cavity can be improved. In addition, the shortest distance of the line segment connecting the boundary O and the position P11 when viewed from the side is preferably 70 mm to 110 mm, more preferably 80 mm to 110 mm, further preferably 80 mm to 100 mm, and particularly preferably 90 mm to 100 mm. In addition, the shortest distance of the line segment connecting the inflection point P2 and the position P11 when viewed from the side is preferably 40 mm to 80 mm, and more preferably 50 mm to 70 mm.

The cross-sectional shape of the handle 3 is preferably a roughly quadrilateral, roughly polygonal, circular, or elliptical, and is more preferably an elliptical shape. Furthermore, it is more preferably an elliptical shape with the width direction as the major diameter. The thickness of the handle 3 is the largest in the handle 3A. The maximum thickness in the handle 3A is preferably greater than 9 mm and less than 14 mm, and more preferably greater than 10.5 mm and less than 12.5 mm.

In addition, the width of the handle 3 is the largest in the handle 3A. The maximum width of the handle 3A is preferably 11 mm or more and 16 mm or less, and more preferably 12.5 mm or more and 14.5 mm or less. Thereby, the grip of the handle 3 can be improved, thereby obtaining excellent operability by grasping, etc. It is preferred that the handle 3A has the maximum thickness and the maximum width. Thereby, the S-shape can be ensured, the insertion property and the feel of use in the oral cavity can be improved, and the grip of the handle 3 can be improved, thereby obtaining excellent operability by grasping, etc. The shortest distance between the position (handle 3Amax) of the handle 3 with the maximum thickness when viewed from the side and the virtual line 50 is preferably 20 mm or more and 32 mm or less, and more preferably 22 mm or more and 26 mm or less. The intersection of the position (handle 3Amax) of the handle 3 at the side view where the thickness is the largest and the surface of the back side extending in the direction perpendicular to the virtual line 50 and facing the handle 3Amax, i.e., the shortest distance between the handle 3Amax' and the virtual line 50 is preferably 8 mm or more and 12 mm or less, and more preferably 10 mm or more and 12 mm or less. In this way, the S-shape can be ensured, the insertability and usability in the oral cavity can be improved, and the grip of the handle 3 can be improved, thereby obtaining excellent operability by grasping.

The ratio of the maximum thickness of the shank 3 to the maximum width of the shank 3 (maximum thickness of the shank 3 /maximum width of the shank 3 ) is preferably 0.6 or more and 1.3 or less, and more preferably 0.7 or more and 1.0 or less.

The ratio of the maximum thickness of the handle 3 to the maximum thickness of the head 5 (maximum thickness of the handle 3 /maximum thickness of the head 5) is preferably 2.3 or more and 7.0 or less, and more preferably 2.8 or more and 4.2 or less.

The ratio of the maximum thickness of the handle 3 to the minimum thickness of the neck 4 (maximum thickness of the handle 3/minimum thickness of the neck 4) is preferably 2.0 or more and 5.6 or less, and more preferably 2.6 or more and 4.8 or less.

The cross-sectional area of the handle 3 is the largest in the handle 3A. The cross-sectional area of the handle 3 is preferably 70 mm ² or more and 200 mm ² or less, and more preferably 90 mm ² or more and 150 mm ² or less.

In the toothbrush 1 of the present embodiment, the first inflection point P1 is located at the head 5, and the second inflection point P2 is provided at the rear end thereof. When the brush body 2 is viewed from the side (FIG. 1), the shortest distance between the inflection point P1 and the inflection point P2 when the first inflection point P1 and the second inflection point P2 are observed from the front side (FIG. 2) is preferably 28 mm or more and 40 mm or less, and more preferably 30 mm or more and 35 mm or less. Thus, in a shape in which the thickness of the neck 4 continuously increases from the head 5 toward the handle 3, the surface between the head 5 and the handle 3 can be continuously connected via the neck 4 in a smooth curve. In addition, a shape in which the neck 4 extends over the entire length and is thinner can be provided.

In the toothbrush 1 of the present embodiment, the first inflection point P1 is located at the head 5, and the second inflection point P2 is provided at the rear end thereof. When the brush body 2 is viewed from above, the distance between the first inflection point P1 and the second inflection point P2 is preferably 28 mm or more and 45 mm or less, more preferably 28 mm or more and 41 mm or less, and further preferably 30 mm or more and 40 mm or less. Thus, in a shape in which the thickness of the neck 4 increases continuously from the head 5 toward the handle 3, the surface between the head 5 and the handle 3 can be continuously connected via the neck 4 with a smooth curve. In addition, a shape in which the neck 4 is thinner over the entire length can be provided.

In the toothbrush 1 of the present embodiment, since it has a thin head 5, a thin neck 4 and a thick handle 3, when a load is applied to the head 5 during brushing, the stress is first concentrated on the first inflection point P1 via the first substantially straight area S1 on the front side. The first inflection point P1 is located in a position facing the second substantially straight area S2 on the back side. Therefore, in the second substantially straight area S2, if the stress received in the back direction at the first inflection point P1 is to be dispersed, the resistance (repulsive force) acts in the front direction.

When the stress concentration in the back direction acts at the first inflection point P1, if the area facing the first inflection point P1 is a substantially straight line shape (second substantially straight line area S2), resistance acts on the front side in the second substantially straight line area S2. Moreover, the resistance is transmitted to the first curved area E1 on the front side facing the second substantially straight line area S2.

In addition, if a first curved area E1 having a center of curvature is provided on the front side of the brush body 2, when stress in the back direction acts concentratedly at the first inflection point P1, resistance tends to act on the front side due to the nature of its curved shape. In addition, the larger the radius of curvature of the first curved area E1, the easier it is for resistance to be dispersed and transmitted.

In addition, if a third curved area E3 having a curvature center on the front side is provided on the back side of the brush body 2, when the stress in the back direction is transmitted to the third inflection point P3, due to the nature of its curved shape, resistance is likely to act on the front side in the third curved area E3. In addition, the larger the curvature radius of the third curved area E3, the easier it is to disperse and transmit resistance.

When the brush body 2 is viewed from the side, the second inflection point P2 is located opposite to the third curved area E3. In addition, since the first curved area E1 and the third curved area E3 are shaped to have a center of curvature on the front side of the brush body 2, the direction of the resistance at the second inflection point P2 is the front side. Here, if a second curved area E2 having a center of curvature on the back side of the brush body 2 is provided on the front side, when the resistance in the front direction acts at the second inflection point P2, due to the nature of its curved shape, the resistance has the property of being easy to act on the back side. In addition, the larger the radius of curvature of the second curved area E2, the easier it is to disperse and transmit the resistance.

In this embodiment, when the resistance in the front direction acts at the second inflection point P2, the resistance in the back direction brought by the second curved area E2 is more likely to act, and is transmitted toward the handle 3, so that stress can be dispersed. In addition, in the second curved area E2, the resistance in the front direction from the third curved area E3 is also transmitted, so the resistance acting on the front side and the back side is offset, and it can be expected that the stress can be further dispersed. In the toothbrush 1 of this embodiment, the characteristic shape of the front side and the back side of the brush body 2 when viewed from the side can avoid stress concentration toward the neck 4, and the entire brush body 2 from the head 5 to the handle 3 is used to disperse stress, thereby suppressing the bending of the neck 4.

A coating material 8 is provided on a portion of the outer peripheral surface of the handle 3. The coating material 8 is formed of a soft resin. The coating material 8 is provided in a spiral shape counterclockwise toward the rear end. The coating material 8 may also be a structure covering the entire outer peripheral surface of the handle 3. As the soft resin, for example, an elastic resin such as a polyolefin elastomer, a styrene elastomer, a polyester elastomer, a polyurethane thermoplastic elastomer, or a silicone resin may be used.

By providing the coating material 8 on a part of the outer peripheral surface of the handle 3, in the toothbrush 1, the gripping property of the handle 3 is improved, and the operability when brushing the molars is improved.

As described above, in the toothbrush 1 of the present embodiment, a toothbrush having excellent insertion properties, operability, and durability when brushing molars can be provided.

The preferred implementation of the present invention has been described above with reference to the accompanying drawings, but the present invention is of course not limited to the examples described above. The shapes or combinations of the components shown in the examples are examples, and various changes can be made based on design requirements, etc. within the scope of the subject matter of the present invention. [Implementation Examples]

The effects of the present invention are further clarified by the following embodiments. Furthermore, the present invention is not limited to the following embodiments, and can be implemented with appropriate changes within the scope of the gist.

(Example 1 to Example 4, Comparative Example 1 to Comparative Example 3) In this embodiment, the toothbrushes of Example 1 to Example 4 and Comparative Example 1 to Comparative Example 3 are manufactured according to the specifications shown in Table 1 below. The toothbrushes shown in Figure 1 and the same as Figure 1 are manufactured. The total length of the handle of each toothbrush is 180 mm, and the dimensions of each part are shown in Table 1. At the head, 23 toothbrush bristles (made of PBT: 7.5 mils) are bundled and made into a hair bundle, and the hair bundle is implanted in the hair implantation pattern shown in Figure 2, and a hair implantation part is provided.

[Operability when cleaning the molars in the oral cavity] Ten monitors cleaned the oral cavity and evaluated the operability of each toothbrush. Operability was evaluated on a 7-point scale from 1 to 7 points, with the higher the score as the operability was perceived to be. The average scores of the ten monitors were classified into the following criteria to judge the operability in the oral cavity. <Criteria> ◎◎ (twin double-circle mark): The average score was 6 points or more. ◎ (double-circle mark): The average score was 5 points or more and less than 6 points. ○ (circle mark): The average score was 4 points or more and less than 5 points. △ (triangle mark): The average score was 3 points or more and less than 4 points. × (cross mark): The average score was 2 points or more and less than 3 points.

[Usability when cleaning molars in the oral cavity] Ten panelists cleaned the oral cavity and evaluated the feeling of the back side of the neck touching the cheek when inserting each toothbrush into the oral cavity. The usability was evaluated on a 7-point scale from 1 to 7 points. The better the insertion feeling, the higher the score. The average score of the 10 panelists was classified into the following criteria to judge the usability in the oral cavity. <Criteria> ◎◎: The average score was 6 points or more. ◎: The average score was 5 points or more and less than 6 points. ○: The average score was 4 points or more and less than 5 points. △: The average score was 3 points or more and less than 4 points. ×: The average score was 2 points or more and less than 3 points.

[Table 1] Embodiment 1 Embodiment 2 Embodiment 3 Embodiment 4 Embodiment 5 Comparison Example 1 Comparison Example 2 Comparison Example 3 Shape Thickness of head (mm) 3.5 3.5 3.5 3.5 3.5 3.5 3.5 5 A curved shape near the border of the head and neck that curves toward the back have without without without without without without without Neck angle (°) 9 9 15 15 15 26 5 5 Neck length (mm) 40 40 40 34 34 40 40 40 Minimum neck thickness 3.6 3.6 3.6 3.6 3.6 3.6 3.6 5.1 The minimum thickness of the neck is 3.0 mm to 4.0 mm in length 8 8 8 8 8 8 8 0 Minimum neck width 4.0 4.0 4.0 4.0 4.0 4.0 4.0 5.5 The minimum width of the neck is 3.0 mm to 4.5 mm in length 19 19 19 19 19 19 19 0 Cross-sectional area at the boundary between neck and handle (mm ² ) 40 40 40 40 40 40 40 40 Hair length (mm) 10 mm 10 mm 10 mm 10 mm 10 mm 10 mm 10 mm 10 mm The tilt plate of the head (angle) without without without without Yes (10°) without without without Handle Material PP PP PP PP PP PP PP PP The distance between the position P11 of the shank 3A located on the distal side relative to the center of the shank 3 in the longitudinal direction and the virtual line 50 is twenty one twenty one twenty four twenty four twenty four twenty one 15 15 Maximum thickness of handle 3A (mm) 11 11 11 11 11 11 11 11 Maximum thickness of handle 3A (mm) 14 14 14 14 14 14 14 14 Radius of curvature R1 70 150 110 90 90 200 300 400 Radius of curvature R2 60 100 70 70 70 100 200 200 Curvature radius R3 300 300 250 200 200 400 500 600 Curvature radius R4 200 200 160 160 160 200 300 300 The shortest distance between P1 and P2 (when viewed from the side) 30 37 37 31 31 47 47 47 Evaluation items The shortest distance between P11 and P2 (when viewed from the side) 54 54 54 60 60 44 44 44 The shortest distance between boundary O and P11 (when viewed from the side) 94 94 94 88 88 104 104 104 Ease of use when cleaning the molars ○ ◎ ◎ ◎◎ ◎◎ △ △ × How it feels when cleaning the molars (the feeling of the back of the neck touching the cheek when inserted into the mouth) ○ ◎ ◎◎ ◎◎ ◎◎ ○ △ ×

As shown in [Table 1], in the toothbrushes of Examples 1 to 4 in which the maximum thickness of the head is greater than 2.0 mm and less than 4 mm and the inclination angle of the neck is greater than 8° and less than 25°, good results were obtained in terms of both operability during molar cleaning and the feeling of use during molar cleaning.

The preferred embodiment of the present invention has been described above with reference to the accompanying drawings, but the present invention is of course not limited to the examples described above. The shapes or combinations of the components shown in the examples are examples, and various changes can be made based on design requirements, etc. within the scope of the main purpose of the present invention. [Industrial Applicability]

The present invention can be applied to toothbrushes.

1: Toothbrush 2: Brush body 3, 3A, 3B, 3Amax, 3Amax': Handle 4: Neck 5: Head 5a~5d: Bristle surface 6: Bristle hole 8: Covering material 40: Brush 41: Bristle bundle 50: Virtual line 51: Flat plate 52: Inclined plate E1: First curve area E2: Second curve area E3: Third curve area E4: Fourth curve area O: Boundary P1: First inflection point P2: Second inflection point P3: Third inflection point P4: Fourth inflection point P11, p11': Position Q1, Q2: Rear end side edge R1~R4: Radius of curvature S1: First straight line area S2: Second straight line area θ: Incline angle

FIG. 1 is a diagram showing an embodiment of the present invention, and is a side view showing the structure of a toothbrush 1. FIG. 2 is a front view of the toothbrush 1 viewed from the side of the implanted bristle surface 5a. FIG. 3 is an enlarged front view of the head 5. FIG. 4 is an enlarged side view of the head 5.

1: Toothbrush

2: Brush the main body

3. 3A, 3B, 3Amax, 3Amax': handle

4: Neck

5: Head

5a: Hair-planted surface

8: Covering material

40: Brush

41: Hair bundle

50:Virtual line

51: Flat plate

52: Inclined plate section

E1: First curve area

E2: Second curve area

E3: The third curve area

E4: Fourth curve area

O:Boundary

P1: First turning point

P2: Second turning point

P3: The third turning point

P4: The fourth turning point

P11, p11': Position

Q1, Q2: rear side edge

S1: The first straight line area

S2: Second straight line area

θ: Tilt angle

Claims (8)

A toothbrush comprises a brush body, wherein the brush body is provided with a handle, a neck extending from the front end of the handle, and a head located at the front end of the neck along the long axis direction, and hair bundles are planted in a plurality of hair planting holes formed on the hair planting surface of the head, and the toothbrush is characterized in that the brush body has a shape in which the thickness of the neck continuously increases from the head toward the handle, the maximum thickness of the head is greater than 2.0 mm and less than 4 mm, and the hair planting surface side when the brush body is observed from the side has: a first straight line area, extending continuously from the hair planting surface to the rear end side in a straight line shape; a first curved line area, having a curvature center on the hair planting surface side, extending in a circular arc shape from a first inflection point located at the rear end of the first straight line area to the rear end side; and a second The curved area has a center of curvature on the back side opposite to the hair implantation surface side, and extends in an arc shape from a second inflection point located at the rear end of the first curved area to the rear end side, and the inclination angle of the neck represented by the angle of intersection of the rear end side edge of the hair implantation hole located at the rearmost side when viewed from the side and the straight line and the virtual line of the second inflection point is greater than 8° and less than 25 ° or less, the virtual line passes through the rear edge of the hair implantation hole located at the rearmost end side and the rear edge of the hair implantation hole located at the second rear end side among the multiple hair implantation holes, and the position in the long axis direction where the distance between the handle on the hair implantation surface side and the virtual line is the longest in the side view is located closer to the front end side than the center of the handle in the long axis direction. The toothbrush as claimed in claim 1, wherein the back side in the side view has: a second straight line area extending continuously from the back side of the head to the rear end side in a straight line shape; and a third curved line area having a curvature center on the hair-planting surface side, extending in an arc shape from a third inflection point located at the rear end of the second straight line area to the rear end side. The toothbrush as claimed in claim 2, wherein the back side in the side view has a fourth curved area, the fourth curved area has a center of curvature on the back side, and extends in an arc shape from a fourth inflection point at the rear end of the third curved area to the rear end side. A toothbrush as described in any one of claim 1 to claim 3, wherein the minimum thickness of the neck is 3.0 mm to 4.0 mm and the length in the long axis direction is more than 5 mm. A toothbrush as described in any one of claim 1 to claim 3, wherein the cross-sectional shape at the boundary between the neck and the handle is elliptical. A toothbrush as described in any one of claim 1 to claim 3, wherein the length of the neck in the direction of the long axis is greater than 25 mm and less than 45 mm. The toothbrush as described in any one of claim 1 to claim 3 does not have a shape that is temporarily curved toward the back side near the boundary between the head and the neck. A toothbrush as described in any one of claim 1 to claim 3, wherein the front end side of the head is inclined toward the hair implantation surface side at an angle of more than 5° and less than 15° relative to the virtual line when viewed from the side.

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