Toothbrush

Abstract

An object of the present invention is to provide a wide-head type toothbrush (1) that can suppress bending of a neck part (4) in a width direction or twisting of the neck part (4) in a circumferential direction around a long axis direction. The maximum length of a head part (3) in the width direction is 12 mm or more and 18 mm or less, the maximum length of the head part (3) in a thickness direction is 2 mm or more and 4 mm or less, the minimum length in the width direction and the minimum length in the thickness direction of the neck part (4) are 3 mm or more and 5 mm or less, in the neck part (4), when a region from a second position to a third position which is at a distance corresponding to 65% of the length of the neck part (4) is denoted by C, and a region from the third position to a fourth position at a boundary between the neck part (4) and the grip part (5) which is at a distance corresponding to 35% of the length of the neck part (4) is denoted by D, a relationship of (a volume of the region D) / (a volume of the region C) ≥ 1.0 is satisfied, and at the fourth position, the maximum length in the width direction is greater than the maximum length in the thickness direction.

Description

toothbrush

[0001] The present invention relates to a toothbrush. This application claims priority to Japanese Patent Application No. 2020-214446, filed on December 24, 2020, the contents of which are incorporated herein by reference.

[0002] There are various types of toothbrush head sizes to suit the preferences and purposes of users. In terms of oral hygiene, compact heads that allow "careful brushing of each tooth one by one" are generally suitable, but for people who lack brushing technique or who place importance on brushing efficiently in a short amount of time, "wide-head" toothbrushes with wide heads that can brush the cervical area, interdental spaces, and tooth surfaces simultaneously are available (for example, Patent Document 1).

[0003] The problem with wide-head toothbrushes is that while they are highly efficient at cleaning multiple areas simultaneously, they tend to be less effective at cleaning each area, particularly in the gaps between the teeth and around the teeth. This is because the bristles of the toothbrush can easily hit areas surrounding the areas you want to brush, causing physical interference.

[0004] Japanese Patent Application Laid-Open No. 2016-13247

[0005] If a "wide-head" toothbrush is designed with a thin neck to facilitate maneuverability within the oral cavity, the center of gravity becomes unstable during brushing, causing the neck to bend in the width direction or twist in the circumferential direction around the longitudinal axis.

[0006] The present invention has been made in consideration of the above points, and aims to provide a "wide head type" toothbrush that can prevent the neck portion from bending in the width direction or twisting in the circumferential direction around the longitudinal axis.

[0007] According to a first aspect of the present invention, a hairdressing device has a head portion located at the tip end side in a longitudinal direction and having a hair-implanted surface, a grip portion located at the rear end side of the head portion, and a neck portion located between the head portion and the grip portion, wherein the maximum length of the head portion in a width direction parallel to the hair-implanted surface and perpendicular to the longitudinal direction is 12 mm or more and 18 mm or less, the maximum length of the head portion in a thickness direction perpendicular to the hair-implanted surface is 2 mm or more and 4 mm or less, the minimum length of the neck portion in the width direction and the minimum length of the neck portion in the thickness direction are 3 mm or more and 5 mm or less, and the maximum length of the head portion from the tip end in the longitudinal direction at which the length in the width direction is greatest is 12 mm or more and 18 mm or less. The toothbrush is characterized in that, when the region from the second position to a first position on the rear end side of the neck portion is defined as A, the region from the first position to a second position at the boundary between the head portion and the neck portion is defined as B, the region in the neck portion from the second position to a third position that is 65% of the length of the neck portion in the longitudinal direction is defined as C, and the region from the third position to a fourth position at the boundary between the neck portion and the grip portion that is 35% of the length of the neck portion in the longitudinal direction is defined as D, the relationship (volume of region D) / (volume of region C) ≥ 1.0 is satisfied, and at the fourth position, the maximum length in the width direction is greater than the maximum length in the thickness direction.

[0008] Furthermore, the toothbrush according to one aspect of the present invention is characterized in that it satisfies the relationship (volume of the region A) / (volume of the region D)≦0.60.

[0009] In the toothbrush according to the above aspect of the present invention, the volume of the region D is 1000 mm ３ The present invention is characterized in that:

[0010] Furthermore, the toothbrush according to one aspect of the present invention is characterized in that it satisfies the relationship (the sum of the volume of the region A and the volume of the region C) / (the sum of the volume of the region A, the volume of the region B, the volume of the region C, and the volume of the region D) ≦ 0.70.

[0011] Furthermore, in the toothbrush according to one aspect of the present invention, the maximum length in the width direction at the fourth position is 11 mm or more, and is characterized by satisfying the relationship (maximum length in the width direction at the fourth position) - (maximum length in the thickness direction at the fourth position) ≧ 2 mm.

[0012] Furthermore, the toothbrush according to one aspect of the present invention is characterized in that it satisfies the relationship 1.5 mm≦(maximum widthwise length of region A)−(maximum widthwise length at the fourth position)≦7 mm.

[0013] Furthermore, the toothbrush according to one aspect of the present invention is characterized in that it satisfies the relationship (maximum length in the thickness direction at the fourth position) - (maximum length in the thickness direction at the third position) ≥ 3 mm.

[0014] The toothbrush according to one aspect of the present invention is characterized in that it satisfies the relationship: (maximum thickness length at the third position) - (average thickness length of region A in the long axis direction) ≤ 2 mm. The average thickness length of region A in the long axis direction is defined as (maximum thickness length of region A in the long axis direction + minimum thickness length of region A in the long axis direction) / 2.

[0015] Furthermore, in the toothbrush according to one aspect of the present invention, the maximum length in the thickness direction of the region C is 4.5 mm or less along the longitudinal axis, and is characterized in that the relationship (maximum length in the width direction at the third position) - (maximum length in the thickness direction at the third position) > 1 mm is satisfied.

[0016] The present invention can provide a wide-head toothbrush that can prevent the neck portion from bending in the width direction or twisting in the circumferential direction around the longitudinal axis.

[0017] Fig. 1 is a diagram showing an embodiment of the present invention, and is a front view of the toothbrush 1 as seen from the bristle implantation surface 3a side. Fig. 2 is a side view showing the configuration of the toothbrush 1. Fig. 3 is a front view showing a partially enlarged view of a head portion 3 and a neck portion 4. Fig. 4 is a partially enlarged view of a head portion 3 and a neck portion 4.

[0018] An embodiment of the toothbrush of the present invention will be described below with reference to Figures 1 to 4. Note that the following embodiment shows one aspect of the present invention, does not limit the present invention, and can be modified as desired within the scope of the technical concept of the present invention. In addition, in the following drawings, the scale and number of each structure are different from the actual structure to make each component easier to understand.

[0019] In the following description, the side of the head portion 3 on which the bristle-implanted surface 3a (described later) is provided (the side opposite the bristle-implanted surface) is referred to as the front side of the toothbrush 1, and the side of the head portion 3 opposite the side on which the bristle-implanted surface 3a faces is referred to as the back side of the toothbrush 1. In addition, the direction in which the handle body 2 extends is referred to as the long axis direction, the direction parallel to the bristle-implanted surface 3a and perpendicular to the long axis direction is referred to as the width direction of the toothbrush 1, and the direction perpendicular to the bristle-implanted surface 3a is referred to as the thickness direction of the toothbrush 1. In addition, the side on the long axis on which the head portion 3 is provided (the head portion 3 side) is referred to as the tip side, and the side on which the grip portion 5 is provided (the grip portion 5 side) is referred to as the rear side, as appropriate.

[0020] Fig. 1 is a front view of the toothbrush 1 as seen from the bristle surface 3a side. Fig. 2 is a side view showing the configuration of the toothbrush 1. Note that the brush 40 is not shown in Fig. 1.

[0021] 1 and 2, the toothbrush 1 of this embodiment includes a handle body 2 made of a resin molded body formed into an elongated shape as a whole, and a brush 40. The total length of the toothbrush 1 is, for example, 150 mm or more and 200 mm or less.

[0022] The handle body 2 is made of hard resin and has a head portion 3 located at the tip end and having a bristle-implanted surface 3a, a grip portion 5 located rearward of the head portion 3, and a neck portion 4 located between the head portion 3 and the grip portion 5. The toothbrush 1 is capable of cleaning the oral cavity with a brush 40 having multiple bristle bundles (not shown) planted on the bristle-implanted surface 3a of the head portion 3.

[0023] An example of a hard resin that forms the handle body 2 is a resin with a flexural modulus (JIS 7171) of 1000 MPa or more and 2800 MPa or less, and it is preferable to use, for example, polypropylene (PP) resin, polyacetal (POM) resin, polybutylene terephthalate (PBT) resin, etc., taking strength into consideration.

[0024] (Shape of Outer Contour Lines on Both Sides of the Handle Body in the Width Direction) As shown in Fig. 1 , in the toothbrush 1 of this embodiment, when the handle body 2 is viewed from the front, the outer contour lines on both sides of the handle body 2 in the width direction are formed symmetrically with respect to a center line located in the center of the width direction and extending in the longitudinal direction. Therefore, in the following description, the outer contour line on one side in the width direction (the lower side in Fig. 1) will be described, and the outer contour line on the other side (the upper side in Fig. 1) will not be described. Furthermore, with regard to the position of the center of curvature of the curved region extending in an arc shape, the position on the center side of the outer contour line in the width direction will be referred to as the inside, and the position on the opposite side of the center side in the width direction will be referred to as the outside.

[0025] When the toothbrush 1 of this embodiment is viewed from the front, the widthwise outer contour of the handle body 2 has a first curved region E1 in which the widthwise length of the head portion 3 expands in an arc shape from the tip end of the head portion 3 toward the rear end, a first straight region L1 in which the widthwise length of the head portion 3 is constant and extends from the rear end of the first curved region E1 to a first position P1 toward the rear end, and a second straight region L2 in which the widthwise length of the head portion 3 is constant from the first position P1 to a second position P2 that is the boundary between the head portion 3 and the neck portion 4. a second straight region L2 that becomes smaller, a third straight region L3 that extends from the second position P2 toward the rear end with a constant length in the width direction of the neck portion 4, a second curved region E2 that has a center of curvature on the outside and extends in an arc shape from the rear end of the third straight region L3 toward the rear end, a third curved region E3 that has a center of curvature on the inside and extends in an arc shape from the rear end of the second curved region E2 toward the rear end, and a fourth straight region L4 that extends from the rear end of the third curved region E3 toward the rear end with a constant length in the width direction of the gripping portion 5.

[0026] (Shape of Outer Contour Line on Front Side of Handle Body) As shown in FIG. 2 , when the handle body 2 of the toothbrush 1 of this embodiment is viewed from the side, the outer contour line on the front side of the handle body 2 has: a fifth straight region L5 that extends in a straight line from the rear end side of the head portion 3 toward the grip portion 5, continuing from the bristle surface 3 a of the head portion 3 toward the rear end; a fourth curved region E4 that has a center of curvature on the front side and extends in an arc from the rear end of the fifth straight region L5 toward the rear end to a fourth position P4 that has a convex vertex 51 and is the boundary between the neck portion 4 and the grip portion 5; the fifth curved region E5 that has a center of curvature on the front side and extends in an arc from the vertex 51 at the fourth position P4 toward the rear end; and a sixth straight region L6 that extends in a straight line from the rear end of the fifth curved region E5 toward the rear end.

[0027] (Outline Shape of the Rear Side of the Handle Body) When the handle body 2 is viewed from the side, the toothbrush 1 of this embodiment has, in the outline of the rear side of the handle body 2, a seventh straight region L7 that extends in a straight line from the tip of the head portion 3 toward the rear end, a sixth curved region E6 that has a center of curvature on the front side and extends in an arc shape from the rear end of the seventh straight region L7 toward the rear end, and an eighth straight region L8 that extends in a straight line from the rear end of the sixth curved region E6 toward the rear end. Note that the straight lines and curves in the outline shape of the toothbrush 1 described above are just one example, and for example, the second straight region L2, the third straight region L3, etc. may be curved or may be a combination of curves and straight lines; the outline shape is not limited to the above description.

[0028] (Head portion) The head portion 3 is a portion that brushes the inside of the oral cavity with multiple bristle bundles, and has a generally rectangular shape with an arc shape in front view, and has rounded corners, as shown in Fig. 1. In this embodiment, the boundary between the head portion 3 and the neck portion 4 is the end point of the curve that forms the corner cutting on the neck portion 4 side in the front view of the head portion 3, i.e., the second position P2 where the bending direction of the curve that forms the corner cutting changes.

[0029] The head portion 3 has a bristle implantation surface 3a on the front side. A plurality of bristle implantation holes 6 are arranged in a row on the bristle implantation surface 3a. The shape and diameter of the bristle implantation holes 6 are not particularly limited, and Fig. 1 shows, as an example, bristle implantation holes 6 that are circular in front view and have the same diameter. The bristle implantation holes 6 are arranged in a plurality of rows (3 to 7 rows in Fig. 2) spaced apart in the width direction according to the width direction length of the head portion 3, and are spaced apart in the longitudinal direction (10 rows in Fig. 2). The bristle bundles that make up the brush 40 are implanted in each of the bristle implantation holes 6.

[0030] The bristle bundles are formed by bundling a number of bristles (filaments) together, folding them in half, and inserting a metal stopper (not shown) called a flat wire between them before driving the bristle bundle into the bristle hole 6. The shape of the head 3 is not particularly limited, and for example, the bristle implantation surface 3a on the front side and the surface on the back side form flat, parallel surfaces.

[0031] The maximum width of the head portion 3 is preferably, for example, 12 mm or more and 18 mm or less. The head portion 3 of this embodiment is a so-called wide head type. By having the wide head portion 3, it is possible to increase the contact area with each part of the teeth and to brush multiple teeth, allowing for efficient brushing.

[0032] The maximum length in the thickness direction of the head portion 3 is, for example, preferably 2 mm or more and 4 mm or less, and more preferably 2.5 mm or more and 3.5 mm or less. The head portion 3 of this embodiment is a so-called thin head. By having a thin head portion 3, even a wide-head type head portion 3 can improve operability for molars and improve cleaning power for molars.

[0033] In this embodiment, in the head portion 3, the region from the tip in the longitudinal direction to the first position P1 at the rearmost end where the widthwise length is greatest is defined as A, and the region from the first position P1 to the second position P2 at the boundary between the head portion 3 and the neck portion 4 is defined as B.

[0034] In addition, if the outer contour of the head portion 3 when viewed from the front is an ellipse or the like, and the rearmost position where the widthwise length is greatest is not further rearward than the center in the longitudinal direction of the head portion 3, the position in the longitudinal direction can be the rear edge of the tufting hole 6 in the rearmost row of the rows with the largest number of tufting holes 6 lined up in the widthwise direction.

[0035] In the head portion 3, the ratio of the total volume of the tufting holes 6 (total hole volume) to the resin volume of the tufting region connecting the outer edges of the outermost tufting holes 6 is preferably 1:2.5 or more. By setting the ratio of the total volume of the tufting holes 6 to the resin volume of the tufting region to be 1:2.5 or more, the amount of resin in the tufting region is greater than that of the tufting holes 6, making the head portion 3 rigid, and therefore, even with a wide and thin head type, it is possible to suppress the occurrence of warping of the head portion 3 and deflection during use.

[0036] The maximum length in the longitudinal direction of the head portion 3 is preferably 25 mm or more. By making the maximum length in the longitudinal direction of the head portion 3 25 mm or more, the thin region becomes longer, making it easier to brush the back of the molars. In addition, the length of the neck portion 4 is prevented from becoming excessively long, allowing brushing without excessive bending of the neck portion 4.

[0037] (Neck Portion) The neck portion 4 is disposed between the grip portion 5 and the head portion 3 and connects the grip portion 5 and the head portion 3. The boundary between the neck portion 4 and the grip portion 5 is a fourth position P4 where the fourth curved region E4 and the fifth curved region E5 intersect in a side view. That is, this is the position where the fourth curved region E4, which has a center of curvature on the outside, connects to the fifth curved region E5, forming a convex apex 51. If the convex apex does not exist or cannot be seen, the boundary between the neck portion 4 and the grip portion 5 is defined as the position where the center of curvature changes in the thickness direction in a side view. If this position cannot be identified, the boundary is defined as the position where the resin changes, for example, from a hard resin to a soft resin such as an elastomer. If this position cannot be identified, the boundary is defined as a position 75 mm from the tip to the rear end of the head portion 3.

[0038] The neck portion 4 has a constant minimum width in a region where the outer contour line is formed by a third straight region L3 in the front view shown in Fig. 1 from a second position P2, which is the boundary with the head portion 3, toward the grip portion 5. The neck portion 4 gradually widens from the minimum width in a region from the rear end of the third straight region L3 to a fourth position P4, which is the rear end of a third curved region E3 where the outer contour line is connected via the second curved region E2.

[0039] The minimum widthwise length of the neck portion 4 is preferably 3 mm or more and 5 mm or less, and more preferably 3.5 mm or more and 4.5 mm or less. The minimum thicknesswise length of the neck portion 4 is preferably 3 mm or more and 5 mm or less. The neck portion 4 of this embodiment is a so-called slim neck type. By setting the minimum widthwise length and minimum thicknesswise length of the neck portion 4 to 3 mm or more and 5 mm or less, it is possible to improve the maneuverability of the back teeth and the cleaning power for the back teeth even with a wide-head type head portion 3.

[0040] The length from the first position P1 at the rear end where the width of the head portion 3 is greatest to the second position P2 at the front end where the width of the neck portion 4 is smallest is preferably 9.0 mm or less. By making the length from the first position P1 to the second position P2 9.0 mm or less, the width of the head portion 3 at the rear end converges sharply, and the length to where the neck portion 4 becomes narrowest can be shortened, improving operability.

[0041] The grip portion 5 is a portion to be gripped by a user and is formed in a long columnar shape. In the side view shown in Figure 1, the grip portion 5 has a constant width from a fourth position P4 at the boundary with the neck portion 4 toward the rear end.

[0042] 2, the thickness of the grip portion 5 gradually decreases from a fourth position P4 at the boundary with the neck portion 4 toward the rear end, up to the rear end of the fifth curved region E5 where the fifth curved region E5 in the outer contour line on the front side reaches a maximum value at the fourth position P4 and the grip portion 5 has a minimum thickness. The length of the grip portion 5 in the thickness direction is constant from the rear end side of the rear end side of the fifth curved region E5.

[0043] The grip portion 5 has, on the front side, a finger rest 50 on which the thumb rests, for example. In a side view, the finger rest 50 is formed at the rear end of the fifth curved region E5, which has a concave curved surface that extends from the apex 51 toward the rear end toward the rear side. By providing the finger rest 50 with a concave curved surface, a good fit can be achieved when the finger rest 50 is pressed against the rear side.

[0044] The finger rest 50 has a convex apex 51 and a flat shape, which makes it possible to adjust the finger rest 50 so that it does not bend excessively in the thickness direction and to prevent the bending from propagating from the neck 4 to the grip 5. Furthermore, by providing the convex apex 51, it is possible to ensure a large thickness on the front side of the grip 5, which prevents the finger rest 50 from bending excessively in the thickness direction and transmits appropriate flexibility to the grip 5 side, thereby preventing the bending from propagating from the neck 4 to the grip 5.

[0045] The length in the longitudinal direction from the tip of the head portion 3 to the tip-side end of the finger rest portion 50 (fourth position P4) is preferably 77 mm or more and 90 mm or less. By setting the length in the longitudinal direction from the tip of the head portion 3 to the tip-side end of the finger rest portion 50 to 77 mm or more and 90 mm or less, the tip side of the finger rest portion 50 becomes sufficiently longer than the tip-side end, making it easier to reach the back of the molars.

[0046] The length in the long axis direction from the narrowest part (second position P2) of the neck portion 4 to the tip end (fourth position P4) of the finger rest portion 50 is preferably 52 mm or more and 70 mm or less. By making the length in the long axis direction from the narrowest part of the neck portion 4 to the tip end of the finger rest portion 50 52 mm or more and 70 mm or less, the neck portion 4 becomes sufficiently long, making it easier to reach the back of the molars.

[0047] From the neck portion 4 to the rear end of the grip portion 5, the thickness distance between the back of the head portion 3 and the back of the grip portion 5, or the thickness distance between the front of the head portion 3 (the bristle surface 3a) and the front of the grip portion 5, is preferably 2.5 mm or less on either the back or front side in the thickness direction, the cross-sectional shape perpendicular to the longitudinal axis is wide and flat, and the thickness from the neck portion 4 to the finger rest 50 on either the back or front side in the thickness direction preferably gradually increases. This increases the thickness from the neck portion 4 to the finger rest 50 in one direction, resulting in a firm brushing experience even with a long neck portion 4 that is less likely to bend. Furthermore, the small difference in thickness between the neck portion 4 and the grip portion 5 makes it easier to brush targeted areas in the oral cavity. Furthermore, the position of the rear end of the third linear region L3 is preferably within ±15 mm in the longitudinal direction from the third position P3 described below.

[0048] When this configuration is adopted, it is preferable that the thickness suddenly increase, for example, by 5 to 10 mm, in the region from the rearmost position where the widthwise length of the neck portion 4 is at its smallest to the tip end of the finger rest portion 50. It is also preferable that the back surface of the head portion 3 and the back surface of the grip portion 5, or the front surface of the head portion 3 and the front surface of the grip portion 5, are parallel. This allows the force transmitted from the grip portion 5 to the head portion 3 to be applied to the teeth with the same vector, resulting in a firm brushing feel and improved operability.

[0049] The grip portion 5 preferably has a thickness length of 9.0 mm or more, a width length of 10 mm or more, a region of constant thickness and width of 80 mm or more, and is formed solely from hard resin, and more preferably has a region of constant thickness and width of 90 mm or more and 120 mm or less. If the region of constant thickness and width of the grip portion 5 is less than 80 mm, it cannot be held with the entire palm and is unstable. If the region of constant thickness and width of the grip portion 5 exceeds 120 mm, the gripping point is not fixed, and the center of gravity is unstable when held at the rear end. By forming the grip portion 5 within the above thickness and width ranges and using only hard resin, it is less likely to bend and can be held firmly, resulting in a firm brushing experience.

[0050] The length of the grip portion 5 in the longitudinal direction from the tip of the finger rest 50 to the rear end of the grip portion 5 is 80 mm or more and 120 mm or less, and the overall length of the handle body 2 is, as mentioned above, preferably 150 mm or more and 200 mm or less. By making the grip portion 5 and the handle body 2 have lengths within the above ranges, they can be firmly gripped, providing a firm brushing experience, and the sufficient overall length ensures ease of gripping and easy access to the oral cavity.

[0051] (Regions A to D) As shown in FIG. 1 , in the neck portion 4, the region from the second position P2 to the third position P3, which is 65% of the length of the neck portion 4 in the longitudinal direction, is defined as C, and the region from the third position P3 to the fourth position P4, which is the boundary between the neck portion 4 and the grip portion 5 and is 35% of the length of the neck portion 4 in the longitudinal direction, is defined as D. It is preferable that the relationship of (volume of region D) / (volume of region C) ≥ 1.0 is satisfied, and it is more preferable that the relationship of (volume of region D) / (volume of region C) ≥ 1.5 is satisfied.

[0052] (Volume of region D) / (Volume of region C) ≧ 1.0, i.e., by making the volume of region D located at the rear end of neck portion 4 equal to or greater than the volume of region C located at the tip end of neck portion 4, the advantage of intraoral operability at the tip end of neck portion 4 can be secured while strengthening the base of neck portion 4 on the gripping portion 5 side, thereby suppressing bending and twisting.

[0053] The volume of each of the regions A to D was calculated by multiplying the area of ​​each of the regions A to D in a front view by the area of ​​each of the regions A to D in a side view by the length in the major axis direction.

[0054] The widthwise length at the third position P3 of the rear end of region C is preferably 6.7 mm or less. By setting the widthwise length at the third position P3 to 6.7 mm or less, a narrow region continues from the second position P2, at the boundary with the head portion 3, of the neck portion 4 to the third position P3, ensuring operability.

[0055] It is preferable that the value expressed by (maximum widthwise length of region C) / (maximum thicknesswise length of region C) be 1.0 or more and 1.8 or less throughout the longitudinal direction of region C. By making the value expressed by (maximum widthwise length of region C) / (maximum thicknesswise length of region C) 1.0 or more and 1.8 or less throughout the longitudinal direction of region C, the neck portion 4 of the wide-head toothbrush 1 can be made wide, making it less likely to twist.

[0056] The position where the widthwise length is 1 mm larger than the second position P2, which is the start point of region C, is preferably located closer to the finger rest 50 than a position that is 40% of the longitudinal length of the neck portion 4, based on the start point of region C, and more preferably located closer to the finger rest 50 than a position that is 50% of the longitudinal length of the neck portion 4. By having the position where the widthwise length is 1 mm larger located closer to the finger rest 50 than a position that is 40% of the longitudinal length of the neck portion 4, a long, narrow region with a small widthwise length exists, thereby improving operability.

[0057] It is preferable that the maximum length in the width direction be greater than the maximum length in the thickness direction at the fourth position P4, which is the rear end of the region D. By making the maximum length in the width direction greater than the maximum length in the thickness direction at the fourth position P4, it is possible to form a shape that is flattened in the width direction.

[0058] The volume of region D is 1000 mm ３ It is preferable that the length is 1300 mm or more. ３ It is more preferable that the volume of the region D is 1000 mm or more. ３ By doing so, the volume of the base of the neck portion 4 becomes sufficiently large, and bending and twisting can be suppressed.

[0059] The maximum widthwise length at the fourth position P4, which is the rear end of region D, is preferably 11 mm or more and satisfies the relationship (maximum widthwise length at the fourth position P4) - (maximum thicknesswise length at the fourth position P4) ≥ 2 mm. By making the maximum widthwise length at the fourth position P4, which is the rear end of region D, 11 mm or more and satisfying the relationship (maximum widthwise length at the fourth position P4) - (maximum thicknesswise length at the fourth position P4) ≥ 2 mm, the base of neck portion 4 is wide, thereby suppressing bending and twisting of neck portion 4 in the widthwise direction.

[0060] Furthermore, it is preferable to satisfy the relationship 1.5 mm≦(maximum widthwise length of region A)−(maximum widthwise length at fourth position P4)≦7 mm. If (maximum widthwise length of region A)−(maximum widthwise length at fourth position P4) is less than 1.5 mm, the head portion 3 will not be suitable for a wide head type, or the base of the neck portion 4 will be abnormally wide, impairing usability. If (maximum widthwise length of region A)−(maximum widthwise length at fourth position P4) is more than 7 mm, the twist suppression effect will be reduced.

[0061] Furthermore, it is preferable to satisfy the relationship (maximum length in the thickness direction at the fourth position P4) - (maximum length in the thickness direction at the third position P3) ≥ 3 mm. By satisfying the relationship (maximum length in the thickness direction at the fourth position P4) - (maximum length in the thickness direction at the third position P3) ≥ 3 mm, the difference in thickness within the region D of the neck portion 4 can be increased. This makes it possible to suppress the propagation of deflection in the thickness direction to the grip portion 5. Therefore, by rapidly increasing the thickness of the neck portion 4 within the short region D, it is possible to suppress twisting while maintaining the advantage of operability.

[0062] It is preferable that region A in the head portion 3 and region D in the neck portion 4 satisfy the relationship (volume of region A) / (volume of region D) ≦ 0.60, and more preferably the relationship (volume of region A) / (volume of region D) ≦ 0.40. The volume of region A excludes the volume of the tufting holes 6 (total hole volume). By satisfying (volume of region A) / (volume of region D) ≦ 0.60, the volume of the head portion 3 can be made smaller than the volume of the rear end side of the neck portion 4. Therefore, by satisfying (volume of region A) / (volume of region D) ≦ 0.60, it is possible to strengthen the rear end side of the neck portion 4 and suppress bending and twisting while maintaining the advantages of efficient brushing and operability provided by a thin, wide head.

[0063] It is preferable that the relationship between regions A and B in the head portion 3 and region C in the neck portion 4 satisfies 0.7≦(volume of region A) / [(volume of region B)+(volume of region C)]≦1.0. The volume of region B does not include the volume of the tufting holes 6 (total hole volume). By satisfying the relationship 0.7≦(volume of region A) / [(volume of region B)+(volume of region C)]≦1.0, the volume of region A becomes smaller than the sum of the volumes of regions B and C, ensuring operability.

[0064] It is preferable to satisfy the relationship of (maximum thickness direction length at the third position P3) - (average thickness direction length of region A in the long axis direction) ≦ 2 mm. The average thickness direction length of region A in the long axis direction is defined as (maximum thickness direction length of region A in the long axis direction + minimum thickness direction length of region A in the long axis direction) / 2. By satisfying the relationship of (maximum thickness direction length at the third position P3) - (average thickness direction length of region A in the long axis direction) ≦ 2 mm, the thickness of the 65% from the head portion 3 to the tip side (head portion 3 side) of the neck portion 4 does not change significantly, thereby improving operability.

[0065] It is preferable that the maximum length in the thickness direction of region C is 4.5 mm or less along the long axis direction and that the relationship (maximum length in the width direction at third position P3) - (maximum length in the thickness direction at third position P3) > 1 mm is satisfied. By having the maximum length in the thickness direction of region C be 4.5 mm or less along the long axis direction and satisfying the relationship (maximum length in the width direction at third position P3) - (maximum length in the thickness direction at third position P3) > 1 mm, the neck portion 4 is wide, and bending and twisting in the width direction of the neck portion 4 can be suppressed, while ensuring the advantage of operability in the portion up to the base of the neck portion 4.

[0066] It is preferable to satisfy the relationship of (sum of the volume of region A and the volume of region C) / (sum of the volume of region A, the volume of region B, the volume of region C, and the volume of region D) ≦ 0.70, and it is more preferable to satisfy the relationship of 0.20 ≦ (sum of the volume of region A and the volume of region C) / (sum of the volume of region A, the volume of region B, the volume of region C, and the volume of region D) ≦ 0.50. By satisfying the relationship of (sum of the volume of region A and the volume of region C) / (sum of the volume of region A, the volume of region B, the volume of region C, and the volume of region D) ≦ 0.70, the proportion of the region that induces twisting relative to the entire handle body 2 can be reduced, making it less likely to twist.

[0067] 3 is a partially enlarged front view of the head portion 3 and a portion of the neck portion 4. As shown in FIG. 3 , in the front view, a line segment S1 connecting point P11 on one side edge of the head portion 3 located at the rearmost end where the width of the head portion 3 is greatest to point P12 located at the most distal end where the width of the neck portion 4 is smallest intersects with a line segment S2 connecting points on both sides of the head portion 3 located at the rearmost end where the width of the head portion 3 is greatest. The smaller angle α is preferably 40° or more and 60° or less. By setting the angle α between line segments S1 and S2 to 40° or more and 60° or less, the width of the rear end of the head portion 3 sharply converges, thereby shortening the length of the neck portion 4 to its narrowest point and improving operability.

[0068] 3, in a front view, a line segment S3 connecting point P11 on one side edge of the head portion 3 located at the rearmost end where the widthwise length of the head portion 3 is greatest to point P13 located at the rearmost end where the widthwise length of the neck portion 4 is smallest, and a line segment S2 connecting points on both side edges of the head portion 3 located at the rearmost end where the widthwise length of the head portion 3 is greatest, and the smaller angle β of the line segment S3 and the line segment S2 connecting these points are preferably 75° or more and 85° or less. By setting the angle β of the line segment S3 and the line segment S2 to 75° or more and 85° or less, the length at which the neck portion 4 is narrowest can be ensured, thereby improving operability.

[0069] 4 is a partially enlarged front view of the head portion 3 and a portion of the neck portion 4. As shown in FIG. 4 , in the front view, a line segment S4 connecting point P14 on one side edge of the head portion 3 located at the most distal end where the widthwise length of the head portion 3 is greatest to point P12 located at the most distal end where the widthwise length of the neck portion 4 is smallest intersects with a line segment S5 connecting points on both sides of the head portion 3 located at the most distal end where the widthwise length of the head portion 3 is greatest. The smaller angle γ is preferably 70° or more and 80° or less. By setting the angle γ between line segments S4 and S5 to 70° or more and 80° or less, the head portion 3 has a long thin region, making it easier to brush the back of the molars.

[0070] As shown in Figure 4, in a front view, a line segment S6 connecting point P14 on one side edge of the head portion 3, where the width of the head portion 3 is greatest, to point P13 on the rearmost side edge of the neck portion 4, where the width of the head portion 3 is smallest, intersects with a line segment S5 connecting two points on both sides of the head portion 3, where the width of the head portion 3 is greatest, at the most distal end. The smaller angle Δ is preferably 80° or more and 85° or less. By setting the angle Δ between line segments S6 and S5 to 80° or more and 85° or less, the head portion 3 has a long thin region, making it easier to brush the backs of the molars. Furthermore, excessive lengthening of the neck portion 4 is prevented, allowing brushing without excessive bending of the neck portion 4.

[0071] As described above, the toothbrush 1 of this embodiment can provide a wide-head type toothbrush that can prevent the neck portion 4 from bending in the width direction or twisting in the circumferential direction around the longitudinal axis direction.

[0072] [Examples] The effects of the present invention will be made clearer by the following examples. Note that the present invention is not limited to the following examples, and can be practiced with appropriate modifications within the scope of the present invention.

[0073] (Examples 1 to 9, Comparative Examples 1 to 2) In these examples, toothbrush samples of Examples 1 to 9 and Comparative Examples 1 and 2 were produced according to the specifications shown in Table 1 below. The dimensions of each part of the toothbrush in each example were as shown in Table 1. Polypropylene (PP) resin was used as the hard resin for the handle body.

[0074] In the samples of Examples 1 to 9 and Comparative Examples 1 and 2, the maximum widthwise length of the head portion was 15.0 mm, the length in the thicknesswise direction of the head portion was a constant 3.0 mm, the maximum widthwise length of the neck portion was 4.0 mm, and the maximum thicknesswise length of the neck portion was 4.0 mm.

[0075] [Evaluation Method] A panel of 10 specialists cleaned the oral cavity with each toothbrush sample and evaluated the "resistance to bending in the width direction" and "feeling of being able to brush thoroughly without twisting" using the following evaluation criteria. The following evaluation was made based on the average scores of the 10 specialist panels. An average score of 5.5 or more by the 10 specialist panels was rated as "◎ (Very Good)", an average score of 4.0 or more but less than 5.5 was rated as "○ (Good)", an average score of 3.0 or more but less than 4.0 was rated as "△ (Not Bad)", and an average score less than 3.0 was rated as "× (Bad)".

[0076] (1) Resistance to bending in the width direction [Evaluation criteria] 7 points: Very resistant to bending. 6 points: Quite resistant to bending. 5 points: Somewhat resistant to bending. 4 points: Can't say either way. 3 points: Somewhat flexible, but acceptable. 2 points: Quite flexible. 1 point: Very flexible.

[0077] (2) Feeling of being able to brush thoroughly without twisting 7 points: Brush thoroughly without any twisting. 6 points: Brush thoroughly with almost no twisting. 5 points: Brush thoroughly with very little twisting. 4 points: Can't say either way. 3 points: Slightly twisted and unable to brush thoroughly, but tolerable. 2 points: Quite twisted and unable to brush thoroughly. 1 point: Extremely twisted and unable to brush thoroughly.

[0078]

[0079] As shown in Table 1, the toothbrush samples of Examples 1 to 9, in which the maximum length of the head portion in the width direction was 12 mm or more and 18 mm or less, the maximum length of the head portion in the thickness direction was 2 mm or more and 4 mm or less, the minimum length of the neck portion in the width direction and the minimum length in the thickness direction were 3 mm or more and 5 mm or less, and which satisfied the relationship (volume of region D) / (volume of region C) ≥ 1.0, and in which the maximum length in the width direction at the fourth position, which is the position of the rear end side of region D, was greater than the maximum length in the thickness direction, received good ratings for both "resistance to bending in the width direction" and "feeling of being able to brush thoroughly without twisting."

[0080] Furthermore, the toothbrush samples of Examples 3 to 4 and 9, which satisfied the relationship (volume of region A) / (volume of region D)≦0.60, received favorable ratings for both "resistance to bending in the width direction" and "feeling of being able to brush thoroughly without twisting."

[0081] In addition, the volume of region D is 1000 mm ３ The toothbrush samples of Examples 5 to 6 and 9 were given good ratings for both "resistance to bending in the width direction" and "feeling of being able to brush thoroughly without twisting."

[0082] Furthermore, the toothbrush samples of Examples 2 to 7 and 9, which satisfied the relationship (sum of the volume of region A and the volume of region C) / (sum of the volume of region A, the volume of region B, the volume of region C and the volume of region D) ≦ 0.70, received favorable evaluations for both "resistance to bending in the width direction" and "feeling of being able to brush thoroughly without twisting."

[0083] Furthermore, the toothbrush samples of Examples 8 and 9, in which the maximum widthwise length at the fourth position was 11 mm or more and the relationship (maximum widthwise length at the fourth position) - (maximum thicknesswise length at the fourth position) ≥ 2 mm was satisfied, received favorable ratings for both "resistance to bending in the widthwise direction" and "feeling of being able to brush thoroughly without twisting."

[0084] From the above results, the toothbrush sample of Example 9 received particularly good ratings in both "resistance to bending in the width direction" and "feeling of being able to brush thoroughly without twisting," followed by the toothbrush samples of Examples 2 and 6, which received even better ratings.

[0085] On the other hand, in comparison example 1, which does not satisfy the relationship (volume of region D) / (volume of region C) ≧ 1.0, and comparison example 2, in which the maximum widthwise length at the fourth position, which is the position of the rear end side of region D, is smaller than the maximum thicknesswise length, good ratings were not obtained for both "resistance to bending in the widthwise direction" and "feeling of being able to brush thoroughly without twisting."

[0086] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to these examples. The shapes and combinations of the components shown in the above examples are merely examples, and various modifications can be made based on design requirements, etc., without departing from the spirit of the present invention.

[0087] The present invention is applicable to toothbrushes.

[0088] REFERENCE SIGNS LIST 1...toothbrush, 3...head portion, 3a...bristle implantation surface, 4...neck portion, 5...grip portion, 6...bristle implantation holes

Claims

1. A toothbrush having a head portion located at the tip side in the major axis direction and having a tufted surface, a gripping portion disposed on the rear end side of the head portion, and a neck portion disposed between the head portion and the gripping portion, wherein the maximum length of the head portion in the width direction parallel to the tufted surface and perpendicular to the major axis direction is 12 mm or more and 18 mm or less, the maximum length of the head portion in the thickness direction perpendicular to the tufted surface is 2 mm or more and 4 mm or less, the minimum length of the neck portion in the width direction and the minimum length in the thickness direction are 3 mm or more and 5 mm or less. In the head portion, a region from the tip to the most rear end side first position where the length in the width direction is the maximum in the major axis direction is defined as A, and a region from the first position to the second position at the boundary between the head portion and the neck portion is defined as B. In the neck portion, a region from the second position to the third position that is 65% of the length of the neck portion in the major axis direction is defined as C, and a region from the third position to the fourth position at the boundary between the neck portion and the gripping portion that is 35% of the length of the neck portion in the major axis direction is defined as D. Then, the relationship (volume of region D) / (volume of region C) ≥ 1.0 is satisfied, and at the fourth position, the maximum length in the width direction is larger than the maximum length in the thickness direction.

2. The toothbrush according to claim 1, satisfying the relationship (volume of region A) / (volume of region D) ≤ 0.

60.

3. The volume of the region D is 1000 mm ３ or more. The toothbrush according to claim 1 or 2.

4. The toothbrush according to any one of claims 1 to 3, satisfying the relationship (sum of the volume of region A and the volume of region C) / (sum of the volume of region A, the volume of region B, the volume of region C, and the volume of region D) ≤ 0.

70.

5. The toothbrush according to any one of claims 1 to 4, wherein the maximum length in the width direction at the fourth position is 11 mm or more, and the relationship (maximum length in the width direction at the fourth position) - (maximum length in the thickness direction at the fourth position) ≥ 2 mm is satisfied.

6. The toothbrush according to any one of claims 1 to 5, satisfying the relationship 1.5 mm ≤ (maximum length in the width direction of region A) - (maximum length in the width direction at the fourth position) ≤ 7 mm.

7. The toothbrush according to any one of claims 1 to 6, satisfying the relationship of (the maximum length in the thickness direction at the fourth position) - (the maximum length in the thickness direction at the third position) ≧ 3 mm.

8. The toothbrush according to any one of claims 1 to 7, satisfying the relationship of (the maximum length in the thickness direction at the third position) - (the average value of the lengths in the thickness direction of the region A extending in the major axis direction) ≦ 2 mm.

9. The toothbrush according to any one of claims 1 to 8, wherein the region C extends in the major axis direction, the maximum length in the thickness direction is 4.5 mm or less, and (the maximum length in the width direction at the third position) - (the maximum length in the thickness direction at the third position) > 1 mm.