TWI840807B - Toothbrush - Google Patents

Abstract

Provided is a toothbrush that is capable of ensuring operability of a handle section and operability in an oral cavity. The toothbrush 1 comprises a bristle implanting section 11, a head section 12, a neck section 13, and a handle section 14. The thickness t of the head section 12 is in range of 2.0 to 4.0 mm. Both the minimum width W1 and the minimum thickness D1 of the neck section 13 are in a range of 3.0 to 4.5 mm. When a straight line connecting the center point in the thickness direction of the handle section 14 at the center position of a grip part of the toothbrush 1 and the center point in the thickness direction of the head section 12 at the center position of the bristle implanting section 11 is expressed as straight line N, and a plane constituting a bristle implanting surface 12 is expressed as plane P, the angle θ between the straight line N and the plane P is in a range of 5.0 to 10.0 degrees. The distance h between the center point in the thickness direction of the handle section 14 and the plane P is in a range of 6.0 to 12.0 mm.

Description

toothbrush

The present invention relates to a toothbrush. This application claims priority based on Japanese Patent Application No. 2016-045368 filed in Japan on March 9, 2016 and Japanese Patent Application No. 2016-212030 filed in Japan on October 28, 2016, and the contents thereof are cited in this application.

According to Patent Documents 1 to 3, a toothbrush with a thinner head is proposed from the viewpoint of operability in the oral cavity. If the head is thinner, a decrease in strength becomes a problem. Therefore, a high-strength resin such as polyacetal (polyoxymethylene (POM)) is used. In particular, in the case of flat-wire hair transplantation in which a metal flat wire is driven into a resin head and the bristles are held, there is a case where the hair transplantation strength and the folding strength of the head become insufficient. [Prior Art Document] [Patent Document]

[Patent Document 1] Japanese Patent Publication No. 7-143914 [Patent Document 2] Japanese Patent Publication No. 2011-4852 [Patent Document 3] Japanese Patent Publication No. 2011-200296

[Problems to be solved by the invention] Through research by the inventors and others, it was found that in the above-mentioned toothbrush, if the neck connecting the head and the handle is thick, the effect of improving the operability in the oral cavity caused by thinning the head is damaged. In particular, if the width of the neck is increased, the operability is further damaged, and the thinness of the head is not conspicuous in appearance and also damages the impression of the product. However, when the neck is made thinner, it sometimes bends too much, which in turn causes problems in operability. In addition, the strength also needs to be further improved. In particular, when using general-purpose resins such as polypropylene (PP) that are commonly used in toothbrushes, the problem is more significant.

One form of the present invention is designed to solve the above-mentioned problem, and one of its purposes is to provide a toothbrush with a thin head that can achieve good operability. [Means for solving the problem]

In order to achieve the above-mentioned purpose, a toothbrush of one form of the present invention includes: a hair-implanting portion, including a plurality of hair bundles; a head, on which the hair-implanting portion is arranged on a hair-implanting surface; a neck, which is extended from the head; and a handle, which is extended from the neck; the characteristics are: the thickness of the head is greater than 2.0 mm and less than 4.0 mm, the minimum width and minimum thickness of the neck are greater than 3.0 mm and less than 4.5 mm, the angle formed by a straight line connecting the thickness direction center point of the handle at the center position of the toothbrush being held and the thickness direction center point of the head at the center position of the hair-implanting portion and the plane constituting the hair-implanting surface is greater than 5.0 degrees and less than 10.0 degrees, and the distance between the thickness direction center point of the handle and the plane is greater than 6.0 mm and less than 12.0 mm.

In one form of the toothbrush of the present invention, the bending elastic coefficient of the material constituting the neck portion may be greater than 1000 MPa and less than 2200 MPa.

In one form of the toothbrush of the present invention, the neck portion may be made of polypropylene resin. [Effect of the invention]

According to one aspect of the present invention, a toothbrush with a thin head that can provide good operability can be realized.

Hereinafter, an embodiment of the present invention will be described using FIG. 1 and FIG. 2. Furthermore, the following embodiment is a form of 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 make it easier to see each component, the scale or quantity of the size is sometimes different depending on the component.

FIG. 1 is a plan view of a toothbrush of the present embodiment. FIG. 2 is a front view of the toothbrush. As shown in FIG. 1 and FIG. 2, the toothbrush 1 of the present embodiment includes: a hair-planting portion 11; a head 12 provided with the hair-planting portion 11; a neck 13 extending from the base end side of the head 12; and a handle 14 extending from the base end side of the neck 13. That is, the head 12 is integrally formed with the neck 13 and the handle 14. Hereinafter, the component in which the head 12, the neck 13 and the handle 14 are integrally formed is referred to as a handle body 15. Furthermore, in FIG. 1, the illustration of the hair-planting portion 11 is omitted.

Here, the upper surface of the head 12 provided with the hair implanting portion 11 is referred to as the hair implanting surface 12a. As shown in FIG. 1 and FIG. 2, the plane P (imaginary plane) constituting the hair implanting surface 12a is set as the XY plane, the direction in which the handle body 15 as a whole extends is set as the X-axis direction, and the direction orthogonal to the X-axis is set as the Y-axis direction. The normal direction of the plane P is set as the Z-axis direction. In the following description, the dimension of each component in the Y-axis direction is referred to as the width of the component, the dimension of each component in the Z-axis direction is referred to as the thickness of the component, and the dimension of each component in the X-axis direction is referred to as the length of the component.

The handle 15 is integrally formed in a long strip shape and can be manufactured by, for example, injection molding using resin as a material. The material constituting the handle 15 may include polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polycyclohexylene dimethylene terephthalate (PCT), polyacetal (POM), polyethylene naphthalate (PEN), polystyrene (PS), acrylonitrile butadiene styrene (ABS), cellulose propionate (CP), polyarylate, polycarbonate, acrylonitrile styrene (AS), etc. Among these resin materials, POM, PBT, PEN, etc. are preferably used in terms of high strength and ease of thinning the head.

In particular, polypropylene generally has high versatility, easy processing and low cost compared to resins such as polyacetal, but has the property of low bending elasticity coefficient. For example, the bending elasticity coefficient of polyacetal is about 2500 MPa, while the bending elasticity coefficient of polypropylene is about 1500 MPa to 2000 MPa. Therefore, polypropylene is a difficult material to use as a material for toothbrushes with thin heads and thin necks. However, by adopting the shape of the toothbrush of the present embodiment described later, it is also possible to use resins with relatively low bending elasticity coefficients such as polypropylene.

In this embodiment, the bending elastic modulus of the material constituting the handle 15, especially the neck 13, is preferably not less than 1000 MPa and not more than 2200 MPa. If the bending elastic modulus is less than 1000 MPa, there is a risk that sufficient strength cannot be obtained when the neck 13 is made thinner. In addition, if the bending elastic modulus exceeds 2200 MPa, there is a risk that the hardness increases but the material becomes brittle.

The resin may be a single resin or two or more resins may be used in combination. In addition, a part or all of the handle 14 of the handle body 15 may be coated with a soft resin. When a part or all of the handle 14 is coated with a soft resin, the user's hand fit when holding the handle 14 is improved, and the gripping fingers can be prevented from slipping. As the soft resin, for example, preferably, a resin of Shore A90 or less can be listed, and more preferably, a resin of Shore A10 to Shore A40 can be listed. Examples of such soft resins include elastomer resins such as polyolefin elastomers, styrene elastomers, polyester elastomers, polyurethane thermoplastic elastomers, and silicone.

The total length of the handle 15 can be determined in consideration of operability, etc. The total length of the handle 15 is, for example, approximately 100 mm to 200 mm.

In a top view, the head 12 has a roughly quadrilateral flat plate shape with four tops formed by curved lines to form cut corners. A plurality of hair implantation holes 12h are provided on the hair implantation surface 12a which is the upper surface of the head 12. A hair implantation portion 11 including a plurality of hair implantation bundles 17 is formed by implanting hair bundles 17 formed by bundling toothbrush bristles in each of the hair implantation holes 12h. The distance d1 between the hair implantation hole 12h located at the front end side of the head 12 and the front end of the head 12, and the distance d2 between the hair implantation hole 12h located at the base end side of the head 12 and the base end of the head 12 are set to be equal. In other words, the boundary position K1 between the neck 13 and the head 12 described below is a position which is separated from the side of the neck 13 by a distance equal to the distance d1 from the hair implantation hole 12h located at the most proximal side of the head 12.

The size of the head 12 is determined in consideration of characteristics such as operability in the oral cavity. If the width of the head 12 is too large, operability in the oral cavity is reduced, and if it is too small, the number of hair bundles 17 to be implanted becomes too small, and the cleaning effect is easily impaired. Therefore, the width of the head 12 is set to about 5 mm to 16 mm, for example.

If the length of the head 12 is too long, the operability in the oral cavity is easily impaired, and if it is too short, the number of hair bundles 17 to be implanted becomes too small, and the cleaning effect is easily impaired. Therefore, the length of the head 12 is set in the range of 10 mm to 33 mm, for example.

The shape of the hair transplanting holes 12h is not particularly limited, and can be a circle such as a perfect circle or an ellipse, or a polygon such as a triangle or a quadrilateral. The number of hair transplanting holes 12h is not particularly limited, and can be set within a range of 10 to 60. The diameter of the hair transplanting holes 12h is determined according to the thickness of the hair bundle 17, and can be set within a range of 1 mm to 3 mm, for example. The arrangement pattern of the hair transplanting holes 12h is not particularly limited, and can be any arrangement pattern such as a so-called grid shape or a sawtooth shape.

The toothbrush bristles constituting the hair bundle 17 include: toothbrush bristles whose diameter gradually decreases toward the hair tip (tapered hair), and toothbrush bristles whose outer diameter is roughly the same except for the round part of the hair tip (straight hair). The material of the toothbrush bristles can be, for example: polyamides such as 6-12 nylon and 6-10 nylon, polyesters such as PET, PBT, polytrimethylene terephthalate (PTT), PEN, and polybutylene naphthalate (PBN), polyolefins such as PP, and synthetic resin materials such as olefin elastomers and styrene elastomers. These resin materials can be used alone or in combination. In addition, the toothbrush bristles can also be a multi-core structure having a core and at least one layer of sheaths arranged on the outside of the core.

The cross-sectional profile of the toothbrush bristles is not particularly limited, and examples thereof include: a perfect circle, an ellipse, or other circular shape, a triangle, a quadrilateral, a pentagon, a hexagon, or other polygonal shape, a star, a three-leaf clover shape, a four-leaf clover shape, and the like.

The thickness of the bristles is not particularly limited, and when the cross-sectional profile is circular, it is set to 3 mil to 11 mil (1 mil = 1/1000 inch = 0.025 mm), for example. The bristle bundle may include bristles of the same thickness, or may be a combination of two or more bristles of different thicknesses. The bristle length is not particularly limited, and is set to 6 mm to 12 mm, for example.

As shown in FIG2 , a curved surface 14a having an arc profile convexly arranged on the side of the hair-implanted surface 12a at the front end side of the handle 14 is formed, with the center position arranged on the side opposite to the hair-implanted surface 12a (lower than the handle 14 in FIG2 ) and the hair-implanted surface 12a side convexly arranged in a side view. Similarly, a curved surface 14b having an arc profile convexly arranged on the side opposite to the hair-implanted surface 12a at the front end side of the handle 14 is formed, with the center position arranged on the side opposite to the hair-implanted surface 12a and the hair-implanted surface 12a side convexly arranged in a side view.

In addition, on the side of the hair-implanted surface 12a at the rear end side of the neck 13, a curved surface 13a is formed with a circular arc profile whose center position is arranged on the side of the hair-implanted surface 12a (higher than the handle 14 in FIG. 2) and is concave on the side of the hair-implanted surface 12a in side view. Similarly, on the side of the rear end side of the neck 13 opposite to the hair-implanted surface 12a, a curved surface 13b is formed with a circular arc profile whose center position is arranged on the side of the hair-implanted surface 12a and is concave on the side of the hair-implanted surface 12a in side view.

As the curved surface 13a and the curved surface 14a respectively advance in the length direction of the handle 14, the intersection angle between the tangent line and the hair implantation surface 12a in the side view continuously changes, but at the intersection of the curved surface 13a and the curved surface 14a, the intersection angle between the tangent lines intersects at an angle α1 of 0 degrees or not 180 degrees. Therefore, an edge K2 is formed at the intersection of the curved surface 13a and the curved surface 14a.

As the curved surface 13b and the curved surface 14b also advance in the length direction of the handle 14, the intersection angle between the tangent line and the hair implantation surface 12a in the side view continuously changes, but at the intersection of the curved surface 13b and the curved surface 14b, the intersection angle of the tangent lines intersects at an angle α2 of 0 degrees or not 180 degrees. Therefore, an edge K3 is formed at the intersection of the curved surface 13b and the curved surface 14b. Therefore, the neck 13 and the handle 14 are connected by curved surfaces 14a and 14b with arc contours that are convex on one side of the fur-implanted surface 12a in a side view along the length direction of the ridges K2 and K3, and curved surfaces 13a and 13b with arc contours that are concave on the fur-implanted surface 12a in a side view along the other side of the length direction of the ridges K2 and K3, thereby forming a roughly S-shape in a side view.

The rear end of the neck 13 is defined by the ridges K2 and K3. Therefore, the handle 14 is disposed further rearward than the ridges K2 and K3, and the neck 13 is disposed in the range between the head 12 and the handle 14.

The end of the hair implantation surface 12a side on the front end side of the handle 14 (closer to the rear end side than the ridge K2) becomes the finger contact portion 19. The user places the thumb on the finger contact portion 19 to hold the handle 14, thereby stably operating the toothbrush 1.

The neck 13 integrally connects the head 12 and the handle 14. For example, the neck 13 is formed in the following shape: the neck 13 is thinnest at a position slightly away from the handle 14 from the boundary position K1 between the head 12 and the neck 13 (the front end of the neck 13), becomes a small cross-sectional area, maintains the cross-sectional area and extends toward the rear end side, and gradually expands at the rear end side until it reaches the boundary K2 with the handle 14. In this way, the neck 13 gradually becomes thicker from the head 12 side toward the handle 14 side, thereby absorbing the bending of the neck 13 when the toothbrush 1 is used in various gripping methods or brushing methods, and the usability is excellent. However, from the perspective of the usability, the neck 13 must be elastic and appropriately curved.

Since the neck 13 contacts the lips when the head 12 is inserted into the oral cavity, the length of the neck 13 is preferably 25 mm to 70 mm.

As shown in Fig. 1, the grip center position G1 of the toothbrush 1 is located on the handle 14. The grip center position G1 is defined as a position 37 mm from the rear end side of the handle 14 from the ridge K2.

As for the way to hold a toothbrush, there are known methods of holding the handle with the whole palm and placing the thumb near the finger contact part, and holding the handle with the thumb like a pen. The inventors of the present invention have made great efforts to study the position of applying force when operating a toothbrush when holding various toothbrushes in various grips. As a result, it has been clarified that a part of the finger is placed at a position of an average of 37 mm from the top point of the finger contact part (the position of the ridge K2), and this position becomes one of the centers of the operating point. Therefore, this position is defined as the grip center. Furthermore, it is also clarified that this position is roughly consistent with the center of gravity of many general toothbrushes.

As shown in FIG2 , if an imaginary straight line connecting the thickness center point G2 of the handle 14 at the grip center position G1 of the toothbrush 1 and the thickness center point S2 of the head 12 at the center position S1 of the hair implantation portion 11 (see FIG1 ) is set as a straight line N, the straight line N is located above (in the +Z direction) the plane P. In other words, the handle body 15 has a shape in which the handle 14 having the grip center position G1 is bent in a manner closer to the hair implantation portion 11 side than the hair implantation surface 12a of the head 12.

The inventors of the present invention have found that in a previous toothbrush whose handle extends in a generally straight line, if the head is thinned and the neck is thinned, the head or the neck is easily bent, and the hair implant portion is easily displaced to the back side of the head (in the -Z axis direction in FIG. 2 ). In particular, when brushing teeth, if the neck is bent, the hair implant portion is displaced to the back side of the head (i.e., away from the teeth or gums) than the usual position, and the force applied to the handle is difficult to be fully transmitted to the hair implant portion. As a result, it can be seen that the operability of the handle is significantly reduced.

Therefore, as a result of diligent research, the inventors of the present invention have come to the conclusion that if the handle 14 side of the handle 15 is bent toward the side of the hair-planting portion 11 more than the plane P constituting the hair-planting surface 12a, and the parameters such as the angle θ formed by the straight line N and the plane P are optimized, the bending of the head 12 or the neck 13 can be offset by the bending of the handle 15. Thus, according to the toothbrush 1 of the present embodiment, when the head 12 is made thinner and the neck 13 is made thinner, even if the head 12 or the neck 13 is bent, the handle operability can be well maintained, and a toothbrush 1 with excellent intraoral operability and handle operability can be realized.

The characteristic design parameters of the toothbrush 1 of this embodiment are described below. [Head thickness t] The thinner the thickness t of the head 12, the better the operability in the oral cavity. However, if it is too thin, the strength of the head 12 is likely to be insufficient. Therefore, the thickness t of the head 12 can be determined by considering the constituent material of the handle 15, the bending elastic modulus, etc. The thickness t of the head 12 is set within the range of 2.0 mm to 4.0 mm. The thickness t of the head 12 is preferably about 2.5 mm to 3.5 mm.

[Minimum width W1 of the neck] The smaller the minimum width W1 of the neck 13, the better the operability in the oral cavity. However, if it is too small, the strength of the neck 13 is likely to become insufficient. Therefore, the minimum width W1 of the neck 13 can be determined by considering the constituent material of the handle 15, the bending elastic coefficient, etc. The minimum width W1 of the neck 13 is set to 3.0 mm to 4.5 mm. The minimum width W1 of the neck 13 is more preferably about 3.5 mm to 4.3 mm.

[Minimum thickness D1 of the neck] The minimum thickness D1 of the neck 13 can be defined as the thickness of the neck 13 at the position where the width of the neck 13 becomes the smallest in the X-axis direction. That is, in the toothbrush 1 of the present embodiment, the shape of the cross section perpendicular to the extension direction of the neck 13 is substantially circular, and the position where the width of the neck 13 becomes the smallest in the X-axis direction coincides with the position where the thickness becomes the smallest. However, the shape of the cross section perpendicular to the extension direction of the neck 13 may not necessarily be circular, and may be, for example, a polygon. In addition, the shape of the cross section perpendicular to the extension direction of the neck 13 may differ depending on the position in the X-axis direction, and the position where the width of the neck 13 becomes the smallest may not necessarily coincide with the position where the thickness becomes the smallest.

Similar to the minimum width W1 of the neck 13, the smaller the minimum thickness D1 of the neck 13 is, the more the operability in the oral cavity can be improved, but if it is too small, the strength of the neck 13 is likely to become insufficient. Therefore, the minimum thickness D1 of the neck 13 can be determined by considering the constituent material of the handle body 15, the bending elastic modulus and other conditions. The minimum thickness D1 of the neck 13 is set to 3.0 mm to 4.5 mm. The minimum thickness D1 of the neck 13 is preferably about 3.5 mm to 4.3 mm. In the case of this embodiment, the shape of the cross-section perpendicular to the extension direction of the neck 13 is roughly circular, so the width is the same as the thickness. That is, the minimum diameter of the neck 13 is preferably 3.0 mm to 4.5 mm, and more preferably 3.5 mm to 4.3 mm.

[Distance a between the base end of the head and the front end of the finger contact part] The larger the distance a between the base end of the head 12 (the boundary position K1 between the neck 13 and the head 12) and the front end of the finger contact part 19 (the boundary K2 between the neck 13 and the handle 14), the deeper the hair implant 11 can reach into the oral cavity, and the more the cleaning effect can be improved to every corner of the oral cavity, but the curvature of the neck 13 becomes larger. On the other hand, the smaller the distance a, the smaller the curvature of the neck 13 can be, but the hair implant 11 is difficult to reach deep into the oral cavity. Therefore, the distance a also depends on the constituent material of the handle 15, the bending elastic coefficient and other conditions, and is set to about 25 mm to 70 mm, for example.

[Grip center angle θ] Hereinafter, the angle θ formed by the straight line N connecting the thickness center point G2 of the handle 14 at the grip center position G1 of the toothbrush 1 and the thickness center point S2 of the head 12 at the center position S1 of the hair implantation portion 11 and the plane P constituting the hair implantation surface 12a is referred to as the grip center angle θ.

If the grip center angle θ is too large, the difference between the extension direction of the handle 14 and the extension direction of the head 12 becomes large, and the operability of the handle 14 decreases. In addition, if the grip center angle θ is too small, the shape of the handle body 15 becomes a straight line, and the original effect of this embodiment cannot be obtained. Taking these circumstances into consideration, the grip center angle θ is set to be greater than 5.0 degrees and less than 10.0 degrees. The grip center angle θ is more preferably greater than 6.0 degrees and less than 8.0 degrees.

[Grip center point height h] The distance between the center point G2 in the thickness direction of the handle 14 at the grip center position G1 of the toothbrush 1 and the plane P constituting the hair implantation surface 12a is defined as the grip center point height h.

Similar to the grip center angle θ, if the grip center height h is too large, the difference between the extension direction of the handle 14 and the extension direction of the head 12 becomes large, and the operability of the handle 14 decreases. In addition, if the grip center height h is too small, the shape of the handle body 15 becomes a straight line, and the original effect of this embodiment cannot be obtained. Taking these circumstances into consideration, the grip center height h is set to be greater than 6.0 mm and less than 12.0 mm. The grip center height h is more preferably greater than 7.0 mm and less than 11.0 mm.

(Bending amount A of the head) The bending amount A of the head is measured by the following method (α). Method (α): The hair-planting surface of the head is directed upward in the vertical direction, and the height of the front end of the handle body is fixed at the reference height when the position of the boundary P1 between the head and the neck of the toothbrush is fixed. Furthermore, with the position of the boundary P1 fixed, a 200 g weight is hung at a position 10±3% from the front end of the hair-planting part relative to the length of the long axis direction of the hair-planting part in the head, and the displacement of the height of the front end of the handle body from the reference height after 10 seconds (in mm) is set as the bending amount A of the head. Furthermore, the so-called "length of the long axis direction of the hair transplantation part" refers to the distance between the front end of the hair transplantation hole located at the most front end side and the rear end of the hair transplantation hole located at the most rear end side when looking down at the head.

In a toothbrush having a head that tapers in width from the neck, the boundary P1 is the end point of the curve forming the two edges of the cut angle from the neck in the head when viewed from above, that is, the position where the bending direction of the curve forming the cut angle changes. Furthermore, the so-called top view refers to observing the toothbrush from the bristle-planting side of the head.

The toothbrush 21 shown in FIG. 3A, FIG. 3B, FIG. 4A and FIG. 4B is described in more detail. The toothbrush 21 includes: a head 22 that is roughly quadrilateral in a top view, a neck 24 extending from the head 22, and a handle 26 extending from the neck 24. A hair implantation portion (not shown) is provided in the head 22. Hereinafter, the head 22, the neck 24 and the handle 26 are collectively referred to as the handle body 210. In a top view, the head 22 expands in width from the front end 29 toward the neck 24, then extends with the same width, then shrinks in width, and finally reaches the boundary P1 with the neck 24. The neck 24 extends from the boundary P1 toward the handle 26 with approximately the same diameter, then expands in diameter and finally reaches the boundary P2 with the handle 26.

The boundary P1 in the toothbrush 21 is the end point of the curve forming the two edges of the cut angle from the neck 24 in the top view of the head 22, that is, the position where the bending direction of the curve forming the cut angle changes. In FIG. 3A, the boundary P1 between the head and the neck is the position where the curve R1 where the width of the two edges forming the cut angle in the head 22 in the top view decreases changes to a straight line forming two edges of the same width. In addition, in the case of a toothbrush whose width increases from the neck toward the handle in the top view, the boundary P1 coincides with the position where the width is the smallest in the head and the neck in the top view. Furthermore, there is a case where it is difficult to specifically specify the position of the boundary P1, such as a toothbrush in which the head and the neck are formed with the same width. In this case, the position 17.5% from the front end 29 of the handle body 210 relative to the length L1 (for example, when the length L1 is 180 mm, the position 31.5 mm from the front end 29 of the handle body 210) is set as the boundary P1.

For example, when the width of the portion of the neck from the head when viewed from above is the same, the width is measured while the position of the portion of the neck from the head is slowly changed toward the head, and the position of the turning point between the portion with the same width and the portion where the width begins to increase is set as the boundary P1. In addition, when the width of the portion of the neck from the head when viewed from above decreases as it approaches the head, the width is measured while the position of the neck from the head is slowly changed toward the head, and the position where the width becomes the smallest is set as the boundary P1.

The bending amount A of the head 22 is measured as follows. As shown in FIG4A, the toothbrush 21 is changed so that the hair-implanted surface 220 faces upward in the vertical direction, and is fixed using a clamp 2100 at the position of the thinnest part of the neck (boundary P1). At this time, the height of the front end 29 of the handle body 210 is set to the reference height _H0 . Then, as shown in FIG4B, a 200 g weight 2102 is hung at the position of S, and the height of the front end 29 of the handle body 210 is measured after 10 seconds, and its height is set to _H1 . The S is a position 10±3% from the front end of the hair-implanted portion relative to the length L4 in the long axis direction of the hair-implanted portion in the head 22 (FIG3A). For example, when the hair-implanted portion is 19 mm, S is a position 2.0 mm from the front end of the hair-implanted portion. Next, the absolute value of the difference between _H1 and _H0 is determined as a (in mm). The a is measured, for example, by a height gauge. The measurement is performed at room temperature of 25±3°C. The measurement is performed five times, and the average value of the displacement a is set as the bending amount A of the head 22.

The bending amount A is preferably 0.4 to 3.0, more preferably 0.4 to 2.5, and further preferably 0.4 to 2.0. In addition, the bending amount A is preferably 0.5 to 3.0, more preferably 0.5 to 2.5, and further preferably 0.5 to 2.0. If the bending amount A is within the above range, the head 22 itself is appropriately bent, the flexibility of the implanted hair part implanted in the head 22 is revealed, and the touch feeling to the gum, that is, the feeling of use becomes better. In addition, if the bending amount A is above the above lower limit, the feeling of use becomes good. If the bending amount A is below the above upper limit, it is easy to ensure sufficient strength in the head 22. Furthermore, the toothbrush 21 will not become too soft, and it is easy to obtain good oral operability and cleaning power. Furthermore, the bending amount A is adjusted by adjusting the bending elastic coefficient of the material of the head (i.e. the material of the handle) or the thickness and width of the head.

(Bending amount B of the neck) The bending amount B of the neck is measured by the following method (β). Method (β): The hair-planting surface of the head is directed upward in the vertical direction, and the height of the front end of the handle body is fixed in the state where the position of the boundary between the neck and the handle of the toothbrush is fixed as the reference height. In the fixed state, a 200 g weight is hung at a position 50±3% from the front end of the hair-planting part relative to the length of the long axis direction of the hair-planting part in the head, and the displacement of the height of the front end of the handle body from the reference height after 10 seconds (in mm) is set as the bending amount B of the neck.

The boundary P2 between the neck and the handle is the end point of the expansion of the neck, that is, the end point of the straight line forming the two edges of the widened part or the position where the bending direction of the curve forming the two edges of the widened part changes when viewed from above. In the case of FIG. 3A, it is the position where the straight line or curve R2 forming the two edges of the widened part in the neck changes to a curve with gradually decreasing width when viewed from above the neck and the handle. In addition, there is a case where it is difficult to specifically define the position of the boundary P2, such as a toothbrush in which the neck and the handle are formed with the same width. In this case, the position 42.2% from the front end 29 of the handle body 210 relative to the length L1 (for example, when the length L1 is 180 mm, the position 76.0 mm from the front end 29 of the handle body 210) is set as the boundary P2.

The bending amount B of the neck 24 of the toothbrush 21 is measured in the same manner as the bending amount A of the head 22, except that the position where the toothbrush 21 is fixed by the clamp 2100 and the position S where the weight 2102 is hung are different. In the measurement of the bending amount B of the neck 24, the position where the toothbrush 21 is fixed by the clamp 2100 is the boundary P2. In addition, S is the length relative to the long axis direction of the implanted hair portion, and is the position of 50±3% from the front end of the implanted hair portion. For example, when the implanted hair portion is 19 mm, S is the position of 9.5 mm from the front end. In addition, the absolute value (in mm) of the difference between the reference height _H0 before hanging the weight 2102 and the height _H1 after 10 seconds of hanging the weight 2102 is obtained in the same manner as the method for measuring the bending amount A of the head. The measurement is performed at a room temperature of 25±3°C. This measurement is performed 5 times, and the average value is set as the bending amount B of the neck 24.

The curvature B is preferably 2.1 to 5.0, more preferably 2.3 to 4.5, and further preferably 2.5 to 4.0. If the curvature B is within the above range, the neck is appropriately curved, and appropriate cushioning is exhibited, and the contact feeling of the implanted hair portion with the gum becomes better. In addition, if the curvature B is above the above lower limit, the bristles of the toothbrush can reach every corner of the oral cavity, such as the deep part of the molar, and the cleaning force in the oral cavity can be further improved. Furthermore, the penetration of the bristles into the periodontal pocket is improved, and the cleaning force of the periodontal pocket can be further improved. If the curvature B is below the above upper limit, it is easy to suppress the decrease in strength of the neck. Furthermore, the toothbrush 21 will not become too soft, and it is easy to obtain a good sense of use. Furthermore, the bending amount B is adjusted by adjusting the bending elastic coefficient of the material of the neck (i.e. the material of the handle) or the minimum diameter of the neck, the cross-sectional shape of the boundary P2, etc.

The product of the curvature A of the head and the curvature B of the neck (A×B) is 0.8 to 10, preferably 1 to 10, further preferably 1 to 6, and further preferably 1 to 3.5. In addition, (A×B) is preferably 2 to 10. If (A×B) is within the above range, an appropriate curvature in coordination between the head 22 and the neck 24 can be obtained. Thereby, when the hair implant part is slid relative to the cleaning object (teeth, gums, etc.), the flexibility and cushioning of the hair implant part are revealed, and the touch feel of the hair implant part becomes good. In addition, the lower limit value of (A×B) is greater than 0.8, preferably greater than 1. In addition, it is more preferably greater than 2. By making (A×B) above the lower limit, a moderate curvature can be obtained, thereby providing a good contact feeling with the gums, and a high massaging effect can be obtained for the gums, thereby improving the feeling of use. The upper limit of (A×B) is 10 or less, preferably 6 or less, and more preferably 3.5 or less. By making (A×B) below the upper limit, the area formed by the head 22 and the neck 24 can be prevented from being excessively curved, thereby reducing operability and cleaning power. In addition, the reduction in the massaging effect on the gums caused by the excessive curvature or the user feeling of looseness when using the toothbrush 21 can be prevented. Furthermore, the strength of the toothbrush 21 can be increased and the durability can be improved.

The curvature A and curvature B are preferably A＜B. If A＜B, the operability of the toothbrush 21 can be further improved. In addition, the difference (B-A) between the curvature A and the curvature B is preferably 1 or more, more preferably 1.5 or more, and further preferably 2 or more. If (B-A) is above the lower limit, the curvature of the neck 24 is kept large relative to the head 22, the cushioning can be improved, and the contact feeling with the gums becomes good, and the user can easily and surely feel the massage effect on the gums. In addition, (B-A) is preferably 4 or less, and more preferably 3 or less. If (B-A) is below the upper limit, the curvature of the neck 24 will not become too large relative to the head 22, and the operability in the oral cavity can be easily improved. Furthermore, it is easy to prevent the user from feeling looseness when using the toothbrush 21. (B-A) is preferably 1 to 4, and more preferably 1 to 3. In addition, the ratio of the bending amount B to the bending amount A (B/A) is preferably 1.5 to 5.0, and more preferably 1.8 to 4.8.

When using the toothbrush 21, hold the handle 26. The shape of the handle 26 is not particularly limited, and it can be a palm-grip style or a pen-grip style. Usually, pressure is applied to the target area while cleaning, so in any holding shape, the thumb or the like is placed near the boundary P2 at the rear end of the neck to hold the handle 26. Then, insert the head 22 into the oral cavity, press the handle 26 while sliding the implanted hair part on the target area to be cleaned. The force applied to the handle 26 is transmitted to the head 22 via the neck 24, and then transmitted from the head 22 to the implanted hair part, whereby the implanted hair part applies pressure to the target area to be cleaned while cleaning. At this time, if the product of the curvature A of the head and the curvature B of the neck (A×B) is 0.8 to 10, a moderate curvature in coordination between the head and the neck can be obtained. As a result, the bristles implanted in the head 22 of the toothbrush 21 can easily reach the deep part of the molars and other corners of the oral cavity, which can improve the cleaning power in the oral cavity. Furthermore, it is easy for the bristles to enter the periodontal pocket, which can improve the cleaning power of the periodontal pocket. In addition, by obtaining a moderate curvature, the flexibility and cushioning of the implanted hair part are improved, the touch of the implanted hair part to the gum becomes good, a good massage effect on the gum can be obtained, and the feeling of use can be improved.

[Example] The following examples are given to explain the present invention in detail, but the present invention is not limited to the following examples and can be implemented with appropriate changes within the scope of the gist.

According to the specifications shown in Table 1, toothbrushes of Examples 1 to 6 and Comparative Examples 1 to 2 are manufactured by injection molding. In the toothbrushes, the width, length, thickness and shape of the handle are all set to be the same. The various resins listed in Table 1 are injection molded to obtain an integral molded product of the head, neck and handle shown in Figures 1 and 2. The arrangement of the implantation holes is set to 3 holes × 1 row, 4 holes × 6 rows, and 3 holes × 1 row from the front end of the head toward the neck. The width and length of the head are shown in Table 1. The toothbrush is manufactured by implanting bundles of conical toothbrush bristles (7.5 mil) containing PBT filaments in the head by flat line implantation.

As evaluation items for each sample, two items were listed: intraoral operability and handle operability. Regarding intraoral operability, "very good" was set to "◎", "good" was set to "○", "slightly bad" was set to "Δ", and "very bad" was set to "×". Similarly, regarding handle operability, "very good" was set to "◎", "good" was set to "○", "slightly bad" was set to "Δ", and "very bad" was set to "×".

[Table 1] Sample Specifications Evaluation items Material Head Neck Handle Thickness t[mm] Width [mm] Length [mm] Minimum width W1[mm] Minimum thickness D1[mm] Distance from head base to finger contact tip a[mm] Grip center angle θ[°] Grip center height h[mm] Oral operability Handle operability Numerical range of the present invention 2.0～4.0 3.0～4.5 3.0～4.5 5.0～10.0 6.0～12.0 Embodiment 1 PP 3.0 9.1 23.0 4.0 4.0 45 6.3 9.5 ○ ◎ Embodiment 2 PP 3.0 10.3 29.7 4.0 4.0 42 6.5 7.2 ○ ◎ Embodiment 3 PP 3.0 10.6 19.5 4.0 4.0 50 6.5 9.5 ◎ ◎ Embodiment 4 PP 3.0 10.5 22.0 4.0 4.0 47 7.0 10.0 ○ ◎ Embodiment 5 PP 3.0 10.3 22.0 4.0 4.0 46 7.5 10.5 ○ ◎ Embodiment 6 PBT 3.5 9.8 23.0 3.5 3.5 53 5.1 8.0 ○ ◎ Comparison Example 1 Saturated polyester 3.5 9.2 25.0 6.3 3.5 38 1.2 0.0 × × Comparison Example 2 PP 4.7 10.3 29.7 5.1 5.0 43 6.3 7.0 Δ ○

As shown in Table 1, the grip center angle θ and grip center height h of the toothbrush of Comparative Example 1 are both outside the numerical range of the present invention. That is, the toothbrush of Comparative Example 1 has a handle that is relatively close to a straight line. Therefore, it is confirmed that the intra-oral operability and handle operability of the toothbrush of Comparative Example 1 are poor. Furthermore, the head thickness t, the minimum width W1 of the neck, and the minimum thickness D1 of the neck of the toothbrush of Comparative Example 2 are outside the numerical range of the present invention. Therefore, it is confirmed that the intra-oral operability of the toothbrush of Comparative Example 2 is poor.

In contrast, all parameters of the head thickness t, the minimum width W1 of the neck, the minimum thickness D1 of the neck, the grip center angle θ, and the grip center height h of the toothbrushes of Examples 1 to 6 are within the numerical range of the present invention. Thus, it is confirmed that the toothbrushes have excellent intraoral operability and handle operability even when the neck is bent.

Generally, when flat-line hair transplantation is used, the stress generated by the flat-line injection is applied to the head. In the case of a thin head, the strength against deformation when force is applied is low. On the other hand, if the neck is thick and strong, sometimes the stress during brushing is concentrated on the head, the curvature of the head becomes larger, and usability decreases. In this case, by making the neck thinner and giving it a certain degree of curvature as in the toothbrush 1 of the present embodiment, the stress during brushing can be dispersed from the head to the entire neck, and usability is improved. Therefore, in the case of flat-line hair transplantation, the effect of the present invention can be particularly significantly achieved.

1, 21: toothbrush 11: hair transplantation part 12, 22: head 12a, 220: hair transplantation surface 12h, 222: hair transplantation hole 13, 24: neck 14, 26: handle 15, 210: handle body 17: hair bundle 19: finger contact part 29: front end of handle body 13a, 13b, 14a, 14b: curved surface 2100: clamp 2102: weight a: absolute value of the difference between _H1 and _H0 d1, d2: distance D1: minimum thickness G1: grip center position G2: center point in thickness direction h: grip center point height _H0 : reference height _H1 : Height K1: Boundary position between head and neck K2, K3: Edges L1, L2, L3, L4: Length N: Straight line P: Planes P1, P2: Boundary R1: Curve R2: Straight line or curve S: Length relative to the long axis of the implanted hair part in the head, 10±3% of the position from the front end of the implanted hair part S1: Center position S2: Center point in thickness direction T2: Thickness t: Thickness W1: Minimum width α1, α2: Angle θ: Grip center point angle

FIG. 1 is a plan view of a toothbrush according to an embodiment of the present invention. FIG. 2 is a side view of the toothbrush. FIG. 3A is a plan view of a toothbrush according to an embodiment of the present invention. FIG. 3B is a side view of a toothbrush according to an embodiment of the present invention. FIG. 4A is a diagram illustrating a method for measuring the amount of curvature of a head. FIG. 4B is a diagram illustrating a method for measuring the amount of curvature of a head.

1: Toothbrush

11: Hair transplantation department

12: Head

12a: Hair-planted surface

13: Neck

14: Handle

15: Handle

17: Hair bundle

19: Finger contact area

13a, 13b, 14a, 14b: curved surface

a: absolute value of the difference between H ₁ and H ₀

d1, d2: distance

D1: Minimum thickness of the neck

G2: Center point of the handle in thickness direction

h: Height of grip center point

K1: The boundary between the head and neck

K2, K3: Ridge

N: Straight line

P: plane

S2: The center point of the head in the thickness direction

t: Thickness of the head

α1, α2: angle

θ: Grip center angle

Claims (10)

A toothbrush comprising: a hair-planting portion including a plurality of hair bundles; a head portion having the hair-planting portion disposed on a hair-planting surface; a neck portion extending from the head portion; and a handle portion extending from the neck portion; and the toothbrush is characterized in that: the thickness of the head portion is greater than 2.0 mm and less than 4.0 mm, the minimum width and minimum thickness of the neck portion are greater than 3.0 mm and less than 4.5 mm, and the hair-planting surface side of the rear end side of the neck portion is formed with a curved surface concave on the hair-planting surface side, so that the toothbrush can be held The angle formed by the straight line connecting the center point of the thickness direction of the handle at the center position and the center point of the thickness direction of the head at the center position of the hair implantation portion and the plane constituting the hair implantation surface is 5.0 degrees or more and 10.0 degrees or less, or the distance between the center point of the thickness direction of the handle and the plane is 6.0 mm or more and 12.0 mm or less, and the hard part of the head, the hard part of the neck and the hard part of the handle are integrally formed using a single hard resin material. A toothbrush as described in claim 1, wherein the distance between the center point of the handle in the thickness direction and the plane formed by the hair-implanted surface is greater than 6.0 mm and less than 12.0 mm, and when the value of the bending amount of the head measured in mm by the following method (α) is the bending amount A, and the value of the bending amount of the neck measured in mm by the following method (β) is the bending amount B, the bending amount A and the bending amount B are The product of (A×B) is greater than 0.8 and less than 10, the difference (B-A) between the bending amount A and the bending amount B is greater than 1 and less than 4, and the ratio (B/A) of the bending amount B to the bending amount A is greater than 1.5 and less than 5.0. Method (α): The hair implantation surface of the head is directed upward in the vertical direction, and the height of the front end of the handle body is used as the reference height when the position of the boundary between the head and the neck is fixed, and then In the fixed state, a 200g weight is hung at a position of 10±3% from the front end of the hair-implanted portion relative to the length of the long axis direction of the hair-implanted portion in the head, and the displacement of the height of the front end of the handle from the reference height after 10 seconds is set as the bending amount A of the head, and its unit is mm; Method (β): The hair-implanted surface of the head is directed upward in the vertical direction to move the neck The height of the front end of the handle body when the position of the edge of the handle is fixed is the reference height. In the fixed state, a 200g weight is hung at a position 50±3% from the front end of the hair implantation part relative to the length of the long axis direction of the hair implantation part in the head, and the displacement of the height of the front end of the handle body from the reference height after 10 seconds is set as the bending amount B of the neck, and its unit is mm. A toothbrush as described in claim 1, wherein the angle formed by a straight line connecting the center point of the thickness direction of the handle at the center position of the toothbrush grip and the center point of the thickness direction of the head at the center position of the hair-implanting portion and the plane constituting the hair-implanting surface is greater than 5.0 degrees and less than 10.0 degrees, and the value of the bending amount of the head measured in mm by the following method (α) is the bending amount A, and the value of the bending amount of the head measured in mm by the following method (β) is the bending amount A. When the value of the bending amount of the neck is determined as the bending amount B, the product of the bending amount A and the bending amount B (A×B) is greater than 0.8 and less than 10, the difference (B-A) between the bending amount A and the bending amount B is greater than 1 and less than 4, and the ratio (B/A) of the bending amount B to the bending amount A is greater than 1.5 and less than 5.0. Method (α): The hair implantation surface of the head is directed upward in the vertical direction to adjust the position of the boundary between the head and the neck. The height of the front end of the handle in a fixed state is the reference height. Furthermore, in the fixed state, a 200g weight is hung at a position of 10±3% from the front end of the hair-implanted portion relative to the length of the long axis direction of the hair-implanted portion in the head, and the displacement of the height of the front end of the handle from the reference height after 10 seconds is set as the bending amount A of the head, and its unit is mm; Method (β): The hair-implanted surface of the head is directed toward the vertical The height of the front end of the handle body when the position of the boundary between the neck and the handle is fixed is taken as the reference height. In the fixed state, a 200g weight is hung at a position of 50±3% from the front end of the hair implantation part relative to the length of the long axis direction of the hair implantation part in the head, and the displacement of the height of the front end of the handle body from the reference height after 10 seconds is set as the bending amount B of the neck, and its unit is mm. A toothbrush as described in claim 2 or claim 3, wherein the bending amount A is greater than 0.4 mm and less than 3.0 mm. A toothbrush as described in claim 2 or claim 3, wherein the bending amount B is greater than 2.1 mm and less than 5.0 mm. A toothbrush as described in claim 2 or claim 3, wherein the bending elastic coefficient of the material constituting the neck is greater than 1000 MPa and less than 2200 MPa. A toothbrush as described in claim 1, wherein the hard resin material is at least one selected from polypropylene, polyethylene terephthalate, polybutylene terephthalate, poly(hexylene terephthalate), polyacetal, polyethylene naphthalate, polystyrene, acrylonitrile-butadiene-styrene resin, cellulose propionate, polyarylate, polycarbonate and acrylonitrile-styrene copolymer resin. A toothbrush as described in claim 2 or claim 3, wherein the neck is made of polypropylene resin. A toothbrush as described in claim 2 or claim 3, wherein the neck gradually thickens from the head side toward the handle side. A toothbrush as described in claim 2 or claim 3, wherein the curved surface is formed on the upper side than the hair-planting surface in a side view, and the handle is located on the upper side than the hair-planting surface.

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