Toothbrush

Abstract

The purpose of this invention is to provide a wide-head toothbrush capable of suppressing neck bending in the width direction and circumferential twisting centered on the long axis. The maximum length of the head in the width direction is 12 mm or more and 18 mm or less, the maximum length of the head in the thickness direction is 2 mm or more and 4 mm or less, the minimum length of the neck in both the width and thickness directions is 3 mm or more and 5 mm or less, and within the neck, when the region from the second position to the third position (65% of the neck length) is designated as C, and the region from the third position to the fourth position (35% of the neck length) at the boundary between the neck and the grip is designated 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.

Description

Technical Field

[0001] This invention relates to a toothbrush.

[0002] This application claims priority based on Japanese Patent Application No. 2020-214446, filed on December 24, 2020, the contents of which are incorporated herein by reference. Background Technology

[0003] Toothbrush head sizes vary widely depending on the user's preferences and purposes. For oral hygiene, a compact head that allows for thorough brushing of each tooth is generally suitable. However, for those who lack brushing skills or prioritize efficient brushing in a short time, a "wide-head" toothbrush with a wide head that can simultaneously brush the neck, interdental spaces, and tooth surfaces is provided (e.g., Patent Document 1).

[0004] The problem with this "wide-headed" toothbrush is that while it is highly efficient at cleaning multiple areas simultaneously, it suffers from poor cleaning precision, particularly in the interdental spaces and neck areas. This is because the tips of the bristles come into contact with surrounding areas beyond the intended cleaning spot, potentially causing physical interference.

[0005] [Existing Technical Documents]

[0006] [Patent Literature]

[0007] Patent Document 1: JP 2016-13247 Summary of the Invention

[0008] [The problem the invention aims to solve]

[0009] When a narrow neck is used in a "wide-headed" toothbrush to take into account the operability in the mouth, the center of gravity becomes unstable during brushing, resulting in the neck bending in the width direction and twisting circumferentially around the long axis.

[0010] The present invention was made in view of the above-mentioned problems, and its object is to provide a "wide-head" toothbrush that can suppress the bending of the neck in the width direction and the circumferential twisting centered on the long axis direction.

[0011] [Methods used to solve problems]

[0012] According to a first aspect of the present invention, a toothbrush is provided, characterized in that,

[0013] It has a head with a front end and a bristle-covered surface located along its long axis, a gripping portion disposed further towards the rear end than the head, and a neck disposed between the head and the gripping portion.

[0014] The maximum length of the head in the width direction, which is parallel to the hair-planting surface and orthogonal to the long axis, is 12mm or more and 18mm or less.

[0015] The maximum length of the head in the thickness direction orthogonal to the hair-planting surface is 2mm or more and 4mm or less.

[0016] The minimum length of the neck in the width direction and the minimum length in the thickness direction are both 3 mm and 5 mm.

[0017] In the head, region A is defined as the area extending along the long axis from the front end to the first position at the rearmost end where the length in the width direction is greatest, and region B is defined as the area extending from the first position to the second position at the boundary between the head and the neck.

[0018] In the neck, when region C extends from the second position to a third position representing 65% of the length relative to the long axis of the neck, and region D extends from the third position to a fourth position representing 35% of the length relative to the long axis of the neck, at the boundary between the neck and the gripping part, the relationship (volume of region D) / (volume of region C) ≥ 1.0 is satisfied.

[0019] At the fourth position, the maximum length in the width direction is greater than the maximum length in the thickness direction.

[0020] Furthermore, in the toothbrush of one aspect of the present invention described above, it is characterized by satisfying the relationship that (volume of region A) / (volume of region D) ≤ 0.60.

[0021] Furthermore, in the toothbrush according to one aspect of the present invention, the volume of the region D is characterized by being 1000 mm². 3 above.

[0022] Furthermore, in the toothbrush of one aspect of the present invention described above, it is characterized by satisfying the relationship that (the sum of the volumes of region A and region C) / (the sum of the volumes of region A, region B, region C, and region D) ≤ 0.70.

[0023] Furthermore, in the toothbrush of one aspect of the present invention described above, the maximum length in the width direction at the fourth position is 11 mm or more, and satisfies the relationship that (maximum length in the width direction at the fourth position) - (maximum length in the thickness direction at the fourth position) ≥ 2 mm.

[0024] Furthermore, in the toothbrush of one aspect of the present invention described above, it is characterized by satisfying the relationship 1.5mm ≤ (maximum length in the width direction of region A) - (maximum length in the width direction at the fourth position) ≤ 7mm.

[0025] Furthermore, in the toothbrush of one aspect of the present invention described above, it is characterized by satisfying the relationship that (maximum length in the thickness direction at the fourth position) - (maximum length in the thickness direction at the third position) ≥ 3 mm.

[0026] Furthermore, in the toothbrush according to one aspect of the present invention described above, it is characterized by satisfying the relationship that (the maximum length in the thickness direction at the third position) - (the average length in the thickness direction of region A along the longitudinal axis) ≤ 2 mm. The average length in the thickness direction of region A along the longitudinal axis is defined as the value represented by (the maximum length in the thickness direction of region A along the longitudinal axis + the minimum length in the thickness direction of region A along the longitudinal axis) / 2.

[0027] Furthermore, in the toothbrush of one aspect of the present invention described above, the region C has a maximum length of 4.5 mm or less in the thickness direction along its longitudinal long axis, satisfying the relationship that (maximum length in the width direction at the third position) - (maximum length in the thickness direction at the third position) > 1 mm.

[0028] [The effects of the invention]

[0029] The present invention can provide a wide-headed toothbrush that can suppress the neck from bending in the width direction or from circumferentially twisting around the long axis. Attached Figure Description

[0030] [ Figure 1 Figure 1 is a front view of the toothbrush 1 viewed from the bristle-embedded surface 3a side, illustrating an embodiment of the present invention.

[0031] [ Figure 2 [] is a side view showing the structure of toothbrush 1.

[0032] [ Figure 3 [This is a magnified frontal view of part of the head 3 and neck 4.]

[0033] [ Figure 4 [This is a magnified frontal view of part of the head 3 and neck 4.]

[0034] [Figure Labels]

[0035] 1…toothbrush; 3…head; 3a…tufted surface; 4…neck; 5…grip; 6…tufted pore Detailed Implementation

[0036] The following is for reference Figures 1-4 The embodiments of the toothbrush of the present invention are described.

[0037] Furthermore, the following embodiments illustrate one aspect of the present invention and do not limit the invention; any modifications can be made within the scope of the technical concept of the present invention. Additionally, in the following drawings, for ease of understanding of the structures, the actual structures and the scales, quantities, etc., differ.

[0038] In the following description, the side of the head 3 with the bristle surface 3a (the side facing the bristle surface) will be referred to as the front side of the toothbrush 1, and the side opposite to the side facing the bristle surface 3a of the head 3 will be referred to as the back side of the toothbrush 1. Furthermore, the direction in which the handle 2 extends will be referred to as the long axis direction, the direction parallel to the bristle surface 3a and orthogonal to the long axis direction will be referred to as the width direction of the toothbrush 1, and the direction orthogonal to the bristle surface 3a will be referred to as the thickness direction of the toothbrush 1. Additionally, the side with the head 3 along the long axis direction (the head 3 side) will be referred to as the front end side, and the side with the grip 5 (the grip 5 side) will be referred to as the rear end side.

[0039] Figure 1 This is a front view of the toothbrush 1 viewed from the bristle-embedded surface 3a.

[0040] Figure 2 This is a side view showing the structure of toothbrush 1. Additionally, Figure 1 The illustration of brushing 40 is omitted in the text.

[0041] like Figure 1 as well as Figure 2 As shown, the toothbrush 1 of this embodiment includes a handle 2 formed entirely of a resin molding body and a brush 40. For example, the total length of the toothbrush 1 is 150 mm or more and 200 mm or less.

[0042] The handle 2 is made of hard resin. The handle 2 has: a head 3 located at the front end and having a bristle surface 3a; a grip portion 5 disposed further towards the rear end than the head 3; and a neck 4 disposed between the head 3 and the grip portion 5. In the toothbrush 1, the oral cavity can be cleaned by a brush 40 having multiple bristle bundles (not shown) embedded in the bristle surface 3a of the head 3.

[0043] As an example of the rigid resin forming the handle 2, resins with a flexural modulus (JIS 7171) of 1000 MPa or more and 2800 MPa or less can be used. For example, considering the strength, polypropylene (PP) resin, polyacetal (POM) resin, polybutylene terephthalate (PBT) resin, etc. are preferred.

[0044] (The shape of the outer contour lines on both sides of the handle in the width direction)

[0045] like Figure 1 As shown, when the toothbrush 1 of this embodiment is viewed from the front, the outer contour lines on both sides of the handle 2 in the width direction are formed symmetrically with respect to the center line located at the center in the width direction and extending in the long axis direction. Therefore, in the following description, the width direction side ( Figure 1 The outline of the middle and lower sides is described, while the description of the other side is omitted. Figure 1 The description of the outline (middle, upper side). Additionally, regarding the location of the center of curvature of the curved region extending in an arc shape, the side facing the center in the width direction relative to the outline is called the inner side, and the side opposite to the center in the width direction is called the outer side.

[0046] The toothbrush 1 of this embodiment, when viewed from a frontal view, has the following characteristics in its width-direction outline: a first curved region E1 in which the width-direction length of the head 3 extends in an arc shape from the front end of the head 3 towards the rear end; a first straight region L1 in which the width-direction length of the head 3 extends consistently towards the rear end from the rear end of the first curved region E1 to a first position P1; and a second straight region L1 in which the width-direction length of the head 3 decreases from the first position P1 to a second position P2, which forms the boundary between the head 3 and the neck 4. 2. Straight region L2; 3. Straight region L3, whose length in the width direction of the neck 4 extends constantly toward the rear end from the 2nd position P2; 2. Curved region E2, which has a center of curvature on the outer side and extends in an arc shape from the rear end of the 3rd straight region L3 toward the rear end; 3. Curved region E3, which has a center of curvature on the inner side and extends in an arc shape from the rear end of the 2nd curved region E2 toward the rear end; and 4. Straight region L4, whose length in the width direction of the grip 5 extends constantly toward the rear end from the rear end of the 3rd curved region E3.

[0047] (The shape of the outline of the front side of the handle)

[0048] like Figure 2As shown, when the toothbrush 1 of this embodiment is viewed from the side, the outer contour line of the handle 2 on the front side of the handle 2 has: a fifth straight region L5 extending in a straight line from the bristle surface 3a of the head 3 toward the grip 5 side; a fourth curved region E4 having a center of curvature on the front side and extending in an arc shape from the rear end of the fifth straight region L5 to the fourth position P4 where a convex apex 51 is provided and which is the boundary between the neck 4 and the grip 5; a fifth curved region E5 having a center of curvature on the front side and extending in an arc shape from the apex 51 of the fourth position P4 toward the rear side; and a sixth straight region L6 extending in a straight line from the rear end of the fifth curved region E5 toward the rear side.

[0049] (The shape of the outline on the back side of the handle)

[0050] When viewed from the side, the toothbrush 1 of this embodiment has the following features on the back side of the handle 2: a seventh straight region L7 extending in a straight line from the front end of the head 3 to the rear end; a sixth curved region E6 having a center of curvature on the front side and extending in an arc shape from the rear end of the seventh straight region L7 to the rear end; and an eighth straight region L8 extending in a straight line from the rear end of the sixth curved region E6 to the rear end.

[0051] In addition, the shape of the outline of the toothbrush 1 can be either a straight line or a curve. For example, the second straight line region L2 and the third straight line region L3 can be a structure of curves or a combination of curves and straight lines as the shape of the outline, and are not limited to those described above.

[0052] (head)

[0053] Head 3 uses multiple bristle tufts to brush the inside of the mouth, such as... Figure 1 As shown, the shape has a roughly rectangular shape with an arc shape when viewed from the front, and also has rounded corners. In this embodiment, the boundary between the head 3 and the neck 4 is the endpoint of the curve forming the chamfer on the side of the neck 4 in the shape of the head 3 when viewed from the front, that is, the second position P2 where the bending direction of the curve forming the chamfer changes.

[0054] The head 3 has a hair-implanting surface 3a on its front side. Multiple hair-implanting holes 6 are arranged side-by-side on the hair-implanting surface 3a. The shape and diameter of the hair-implanting holes 6 are not particularly limited. Figure 1 As an example, the image shows circular hair implantation holes 6 of uniform diameter viewed from the front. Regarding the hair implantation holes 6, multiple holes are arranged at intervals along the width direction corresponding to the length of the head 3 in the width direction. Figure 2 In the middle, 3 to 7) hair implantation holes 6 are arranged in multiple rows at intervals along the long axis direction. Figure 2 (In the middle, 10 columns). In the hair implantation hole 6, hair bundles constituting brush 40 are implanted respectively.

[0055] By bundling multiple bristles (filaments) together, folding them in half, and inserting a metal anti-hair loss device (not shown) called a flat wire between them into the hair implantation hole 6, hair bundles are implanted in each hair implantation hole 6. Regarding the head 3, its shape is not particularly limited; for example, the hair implantation surface 3a on the front side and the surface on the back side form mutually flat and parallel surfaces.

[0056] The maximum length in the width direction of the head 3 is preferably 12 mm or more and 18 mm or less. The head 3 in this embodiment is a so-called wide-head type. By having a wide-head type head 3, the contact area with each part of the teeth can be increased, and since multiple teeth can be brushed, brushing can be done effectively.

[0057] The maximum length in the thickness direction of the head 3 is preferably 2 mm or more and 4 mm or less, more preferably 2.5 mm or more and 3.5 mm or less. The head 3 in this embodiment is a so-called thin brush head. By having a thin head 3, even a wide-headed head 3 can improve operability on molars and improve the cleaning force on molars.

[0058] In this embodiment, in the head 3, the region from the front end in the long axis direction to the first position P1 at the last end where the length in the width direction is the largest is designated as A, and the region from the first position P1 to the second position P2 at the boundary between the head 3 and the neck 4 is designated as B.

[0059] Furthermore, if the outline of the head 3 is elliptical when viewed from the front, and the position of the last end side, which is the longest in the width direction, is not closer to the rear end side than the center in the long axis direction of the head 3, it can be located in the long axis direction of the rear end side edge of the row with the largest number of hair implantation holes 6 arranged in the width direction.

[0060] In the head 3, the ratio of the total volume of the hair implantation hole 6 (total hole volume) to the resin volume of the hair implantation area connected to the outer edge of the hair implantation hole 6 located on the outermost periphery is preferably 1:2.5 or more.

[0061] By setting the ratio of the total volume of the hair implantation hole 6 to the resin volume of the hair implantation area to 1:2.5 or higher, the amount of resin in the hair implantation area increases relative to the hair implantation hole 6, and the head 3 becomes more rigid. Therefore, even with a wide and thin head type, the warping of the head 3 and the occurrence of deflection during use can be suppressed.

[0062] The maximum length of the head 3 along its long axis is preferably 25 mm or more. By setting the maximum length of the head 3 along its long axis to 25 mm or more, the thinner area becomes longer, making it easier to brush deep into the molars. In addition, it can prevent the neck 4 from becoming too long, allowing brushing to be performed without excessive bending of the neck 4.

[0063] (neck)

[0064] The neck 4 is the portion disposed between the grip 5 and the head 3, connecting the grip 5 and the head 3. The boundary between the neck 4 and the grip 5 is the fourth position P4 where the fourth curved region E4 and the fifth curved region E5 intersect in a side view. That is, it is the position of the apex 51 that connects the fourth curved region E4 and the fifth curved region E5, which have a center of curvature on the outer side, and forms a convex shape.

[0065] In the absence of a convex apex or in the absence of a convex apex that can be identified, the boundary between the neck 4 and the grip 5 is the position where the center of curvature in the thickness direction changes in a side view. If the position cannot be determined, it may be set as the position where the resin changes from a hard resin to a soft resin such as an elastomer. If the position cannot be determined, it may be set as the position 75 mm from the front end of the head 3 toward the rear end.

[0066] Neck 4, from position P2, which is the boundary with head 3, towards gripping part 5, Figure 1 From the frontal view shown, the outline has a constant minimum width in the region formed by the third straight line region L3. Regarding the neck 4, the width gradually increases from the minimum width in the region from the rear end of the third straight line region L3 to the fourth position P4, which is the rear end of the third curved region E3 connected by the second curved region E2.

[0067] The minimum length of the neck 4 in the width direction is preferably 3 mm or more and 5 mm or less, more preferably 3.5 mm or more and 4.5 mm or less. The minimum length of the neck 4 in the thickness direction is preferably 3 mm or more and 5 mm or less. The neck 4 in this embodiment is a so-called narrow-neck type. By setting the minimum length of the neck 4 in the width direction and the minimum length in the thickness direction to 3 mm or more and 5 mm or less, even a wide-headed head 3 can improve the operability of the molars and increase the cleaning force of the molars.

[0068] The length from the first position P1, where the length in the width direction of the head 3 is the largest at the last end, to the second position P2, where the length in the width direction of the neck 4 is the smallest at the foremost end, is preferably 9.0 mm or less.

[0069] By setting the length from position 1 P1 to position 2 P2 to less than 9.0 mm, the width of the rear end of the head 3 tapers sharply, which reduces the length of the neck 4 until it becomes the thinnest part, thus improving operability.

[0070] (Holding part)

[0071] The grip part 5 is the part that the user holds, and it is formed into a long column shape.

[0072] exist Figure 1 From the side view shown, the length in the width direction is constant from the fourth position P4 at the boundary between the grip 5 and the neck 4 towards the rear end.

[0073] exist Figure 2 From the side view shown, the thickness of the grip portion 5 gradually decreases from the fourth position P4, which is the boundary with the neck 4, towards the rear end, reaching its maximum at the fourth position P4 in the fifth curved region E5 of the front outline, and then decreasing to the rear end of the fifth curved region E5, where the grip portion 5 has the minimum thickness. Regarding the grip portion 5, its length in the thickness direction towards the rear end is constant compared to the rear end of the fifth curved region E5.

[0074] The gripping part 5, on the front side, for example, has a finger contact part 50 for thumb contact. In a side view, the finger contact part 50 is formed at the rear end of a fifth curved region E5 that forms a concave curved surface facing the rear side, starting from the apex 51 and extending towards the rear side. By providing a concave curved surface on the finger contact part 50, a suitable fit can be achieved when the finger contact part 50 is pressed towards the rear side.

[0075] By having a convex apex 51 and a flat shape, the finger contact portion 50 can be adjusted to prevent excessive deflection in the thickness direction and to suppress the propagation of deflection from the neck 4 to the grip portion 5.

[0076] In addition, by setting a convex vertex 51, it can be ensured that the wall thickness of the front side of the grip portion 5 is relatively large, so that it will not bend excessively in the thickness direction. Furthermore, by transmitting moderate softness to the grip portion 5 side, the propagation of bending from the neck 4 to the grip portion 5 can be suppressed.

[0077] The length along the major axis from the front end of the head 3 to the front end of the finger contact portion 50 (position 4 P4) is preferably 77 mm or more and 90 mm or less.

[0078] By setting the length along the long axis from the front end of the head 3 to the front end of the finger contact portion 50 to 77 mm or more and 90 mm or less, the front end becomes long enough compared to the front end of the finger contact portion 50, making it easy to reach the depth of the molar.

[0079] The length along the major axis from the narrowest part of the neck 4 (second position P2) to the front end of the finger contact part 50 (fourth position P4) is preferably 52 mm or more and 70 mm or less.

[0080] By setting the length along the long axis from the thinnest part of the neck 4 to the front end of the finger contact part 50 to 52 mm or more and 70 mm or less, the neck 4 becomes long enough to easily reach the depths of the molar.

[0081] Preferably, from the neck 4 to the rear end of the grip portion 5, the distance in the thickness direction between the back side of the head 3 and the back side of the grip portion 5, or the distance in the thickness direction between the front side of the head 3 (furry surface 3a) and the front side of the grip portion 5, is 2.5 mm or less, and the cross-sectional shape orthogonal to the long axis direction is a wide and flat shape. The thickness gradually increases from the neck 4 to the finger contact portion 50, depending on whether it is the back side or the front side of the thickness direction.

[0082] Accordingly, since the thickness increases in one direction from the neck 4 to the finger contact portion 50, even the elongated neck 4 is difficult to bend, providing ample brushing comfort. Furthermore, since the difference in thickness direction between the neck 4 and the grip portion 5 is small, it is easy to brush target areas within the mouth. Additionally, the rear end of the third straight region L3 is preferably located within ±15mm along its long axis from the third position P3 described later.

[0083] When this structure is adopted, preferably, the thickness increases sharply by, for example, 5 to 10 mm, in the region from the rearmost side where the length in the width direction of the neck 4 is the smallest to the front end of the finger contact portion 50. Furthermore, it is preferable that the back side of the head 3 is parallel to the back side of the grip portion 5, or the front side of the head 3 is parallel to the front side of the grip portion 5. This ensures that the force transmitted from the grip portion 5 to the head 3 is applied to the teeth with the same vector, resulting in sufficient brushing comfort and improved operability.

[0084] Regarding the grip portion 5, it is preferable that the length in the thickness direction is 9.0 mm or more, the length in the width direction is 10 mm or more, and there is a region with a thickness and width of 80 mm or more that is constant, and it is formed only of hard resin; more preferably, there is a region with a thickness and width of 90 mm or more and 120 mm or less that is constant.

[0085] When the thickness and width of the grip portion 5 are constant in an area less than 80mm, it cannot be held with the entire hand and is unstable. When the thickness and width of the grip portion 5 are constant in an area greater than 120mm, the gripping position is uncertain, and the center of gravity is unstable when gripping from the rear end. By forming the thickness and width of the grip portion 5 within the above range and using only hard resin, it is difficult to bend and can be firmly gripped, resulting in sufficient brushing comfort.

[0086] The length of the grip portion 5 along its long axis from the front end of the finger contact portion 50 to the rear end of the grip portion 5 is 80 mm or more and 120 mm or less. As described above, the total length of the handle 2 is preferably 150 mm or more and 200 mm or less.

[0087] By setting the lengths of the grip portion 5 and the handle 2 within the aforementioned range, a firm grip can be achieved, providing ample brushing comfort, while ensuring sufficient overall length, thereby guaranteeing ease of grip and easy access to the oral cavity.

[0088] (Area A to Area D)

[0089] like Figure 1 As shown, in the neck 4, when the region from the second position P2 to the third position P3, which is 65% of the length relative to the long axis of the neck 4, is called C, and the region from the third position P3 to the fourth position P4, which is 35% of the length relative to the long axis of the neck 4 and is the boundary between the neck 4 and the grip portion 5, is called D, it is preferable to satisfy the relationship that (volume of region D) / (volume of region C) ≥ 1.0, and more preferably to satisfy the relationship that (volume of region D) / (volume of region C) ≥ 1.5.

[0090] (Volume of region D) / (Volume of region C)≥1.0, that is, by making the volume of region D on the posterior side of neck 4 greater than the volume of region C on the anterior side of neck 4, the advantage of intraoral operability on the anterior side of neck 4 can be ensured, and the root of the gripping part 5 side of neck 4 can be made firm, thus suppressing deflection and twisting.

[0091] The volumes of regions A through D are calculated by multiplying the area of ​​each region A through D from the frontal view by the area from the side view by the length along the major axis.

[0092] The length in the width direction at the third position P3 of the rear end of region C is preferably 6.7 mm or less.

[0093] By setting the length in the width direction at position 3 P3 to less than 6.7mm, the neck 4 is a continuous fine area from position 2 P2, which is the boundary with the head 3, to position 3 P3, thus ensuring operability.

[0094] The value of (maximum length in the width direction of region C) / (maximum length in the thickness direction of region C) along the entire long axis of region C is preferably 1.0 or more and 1.8 or less.

[0095] By making the value of (maximum length in the width direction of region C) / (maximum length in the thickness direction of region C) greater than 1.0 and less than 1.8 in the entire long axis direction running through region C, the neck 4 in the wide-head toothbrush 1 becomes wider and thus becomes less prone to twisting.

[0096] The position where the length in the width direction is increased by 1 mm relative to the second position P2, which is the starting point of region C, is preferably located closer to the finger contact portion 50 than the position where the length in the long axis direction of the neck 4 is 40% of the length. More preferably, it is located closer to the finger contact portion 50 than the position where the length in the long axis direction of the neck 4 is 50% of the length.

[0097] The position where the length in the width direction is increased by 1 mm is located closer to the finger contact portion 50 than the position where the length in the long axis direction of the neck 4 is 40%. As a result, the area with a small and thin length in the width direction is long, thus improving operability.

[0098] At the fourth position P4 of the rear end of region D, the maximum length in the width direction is preferably greater than the maximum length in the thickness direction.

[0099] At position 4, P4, by making the maximum length in the width direction greater than the maximum length in the thickness direction, a flat shape in the width direction can be formed.

[0100] The volume of region D is preferably 1000 mm². 3 The above, preferably 1300mm 3 above.

[0101] By setting the volume of region D to 1000 mm 3 Thus, the volume of the root of neck 4 becomes large enough to suppress flexure and torsion.

[0102] Preferably, the maximum length in the width direction at the fourth position P4 at the rear end of region D is 11 mm or more, and satisfies the relationship that (maximum length in the width direction at the fourth position P4) - (maximum length in the thickness direction at the fourth position P4) ≥ 2 mm.

[0103] By making the maximum length in the width direction at the fourth position P4 of the rear end of region D greater than 11 mm, and satisfying the relationship (maximum length in the width direction at the fourth position P4) - (maximum length in the thickness direction at the fourth position P4) ≥ 2 mm, since the root of the neck 4 is wide, bending and twisting of the neck 4 in the width direction can be suppressed.

[0104] In addition, it is preferable to satisfy the relationship that 1.5mm ≤ (maximum length in the width direction of region A) - (maximum length in the width direction of position P4) ≤ 7mm.

[0105] If the difference between the maximum length in the width direction of region A and the maximum length in the width direction of position P4 is less than 1.5mm, it cannot be used as a wide-head type head 3, or the base of the neck 4 will become abnormally wide, impairing the user experience. If the difference between the maximum length in the width direction of region A and the maximum length in the width direction of position P4 is greater than 7mm, the twisting suppression effect is reduced.

[0106] In addition, it is preferable to satisfy the relationship that (maximum length in the thickness direction at position 4 P4) - (maximum length in the thickness direction at position 3 P3) ≥ 3 mm.

[0107] By satisfying the relationship that (maximum length in the thickness direction at position 4 P4) - (maximum length in the thickness direction at position 3 P3) ≥ 3 mm, the thickness difference can be increased within region D of the neck 4. Therefore, the propagation of deflection in the thickness direction toward the gripping part 5 can be suppressed. Thus, by drastically increasing the thickness of the neck 4 within the short region D, advantages in operability can be ensured while torsion is suppressed.

[0108] Regarding region A in the head 3 and region D in the neck 4, it is preferable to satisfy the relationship that (volume of region A) / (volume of region D) ≤ 0.60, and more preferably to satisfy the relationship that (volume of region A) / (volume of region D) ≤ 0.40. The volume of region A is calculated by removing the volume of the hair implantation holes 6 (total hole volume).

[0109] By making the ratio of (volume of region A) / (volume of region D) ≤ 0.60, the volume of the head 3 can be reduced relative to the volume of the rear end of the neck 4. Therefore, by making the ratio of (volume of region A) / (volume of region D) ≤ 0.60, the advantages of efficient brushing and operability based on the thin, wide brush head can be ensured, while the rear end of the neck 4 can be made firm and deflection and twisting can be suppressed.

[0110] Regarding region A and region B in head 3 and region C in neck 4, it is preferable to satisfy the relationship 0.7 ≤ (volume of region A) / [(volume of region B) + (volume of region C)] ≤ 1.0. The volume of region B is calculated by removing the volume of the hair implantation holes 6 (total hole volume).

[0111] 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 relative to the sum of the volumes of region B and region C, thus ensuring operability.

[0112] Preferably, the relationship is satisfied that (maximum length in the thickness direction at position 3 P3) - (average length in the thickness direction of region A along the longitudinal axis) ≤ 2 mm. The average length in the thickness direction of region A along the longitudinal axis is defined as the value expressed as (maximum length in the thickness direction of region A along the longitudinal axis + minimum length in the thickness direction of region A along the longitudinal axis) / 2.

[0113] By satisfying the relationship that (maximum length in the thickness direction at position 3 P3) - (average length in the thickness direction of region A along the longitudinal axis) ≤ 2 mm, the thickness variation of the front end side (head 3 side) of the neck 4 from head 3 is small, thus improving operability.

[0114] Along the longitudinal axis, the maximum length of the thickness direction of the preferred region C is less than 4.5 mm, satisfying the relationship that (maximum length of the width direction at position 3 P3) - (maximum length of the thickness direction at position 3 P3) > 1 mm.

[0115] By making the maximum length of region C in the thickness direction along the longitudinal axis less than 4.5 mm, satisfying the relationship (maximum length in the width direction at the third position P3) - (maximum length in the thickness direction at the third position P3) > 1 mm, the operability advantage in the part up to the root of neck 4 is ensured, and the neck 4 is wide, which can suppress the deflection and twisting of neck 4 in the width direction.

[0116] Preferably, the relationship is satisfied that (the sum of the volumes of region A and region C) / (the sum of the volumes of region A, region B, region C, and region D) ≤ 0.70, and more preferably, the relationship is satisfied that 0.20 ≤ (the sum of the volumes of region A and region C) / (the sum of the volumes of region A, region B, region C, and region D) ≤ 0.50.

[0117] By satisfying the relationship (the sum of the volumes of region A and region C) / (the sum of the volumes of region A, region B, region C, and region D) ≤ 0.70, the proportion of the region that induces twisting can be reduced relative to the entire handle 2, making it difficult to twist.

[0118] Figure 3 It is a magnified frontal view of part of the head 3 and neck 4.

[0119] like Figure 3 As shown, in a frontal view, the angle α of the line segment S1 connecting the point P11 on the side edge of the head 3 where the length in the width direction of the head 3 is the largest and the point P12 on the front edge where the length in the width direction of the neck 4 is the smallest, and the line segment S2 connecting the points on the two sides of the head 3 where the length in the width direction of the head 3 is the largest, is preferably 40° or more and 60° or less.

[0120] By making the angle α at which line segment S1 intersects line segment S2 between 40° and 60°, the width of the rear end side of the head 3 converges sharply, which can reduce the length until the neck 4 becomes the thinnest part, thereby improving operability.

[0121] like Figure 3 As shown, in a frontal view, the angle β of the line segment S3 connecting the point P11 on the side edge of the head 3 where the length in the width direction of the head 3 is the largest and the point P13 on the rearmost side where the length in the width direction of the neck 4 is the smallest, and the line segment S2 connecting the points on the two sides of the head 3 where the length in the width direction of the head 3 is the largest, is preferably 75° or more and 85° or less.

[0122] By ensuring that the angle β at which line segment S3 intersects line segment S2 is between 75° and 85°, the length up to the neck 4, which is the thinnest part, can be guaranteed, thus improving operability.

[0123] Figure 4 It is a magnified frontal view of part of the head 3 and neck 4.

[0124] like Figure 4 As shown, in a frontal view, the angle γ of the line segment S4 connecting the point P14, which is the longest side edge of the head 3 with the longest length in the width direction of the head 3, and the point P12, which is the shortest side edge of the neck 4, and the line segment S5 connecting the two sides edge of the head 3 with the longest length in the width direction of the head 3, is preferably 70° or more and 80° or less.

[0125] By making the angle γ at the intersection of line segment S4 and line segment S5 between 70° and 80°, the head 3, which has a long and thin area, is easily brushed deep into the molars.

[0126] like Figure 4 As shown, in a frontal view, the angle Δ of the line segment S6 connecting the point P14, which is the longest side edge of the head 3 with the longest length in the width direction of the head 3, and the point P13, which is the shortest side edge of the neck 4, and the line segment S5 connecting the two sides edge of the head 3 with the longest length in the width direction of the head 3, is preferably 80° or more and 85° or less.

[0127] By making the angle Δ at the intersection of line segment S6 and line segment S5 between 80° and 85°, the head 3, which has a long and thin area, is made easier to brush deep into the molars. Furthermore, it prevents the neck 4 from becoming excessively long, allowing brushing to be performed without excessive deflection of the neck 4.

[0128] As described above, the toothbrush 1 of this embodiment can provide a wide-headed toothbrush that can suppress the neck 4 from bending in the width direction or twisting circumferentially around the long axis direction.

[0129] [Example]

[0130] The effects of the present invention will be made clearer through the following embodiments. Furthermore, the present invention is not limited to the following embodiments and can be implemented with appropriate modifications without changing its spirit.

[0131] (Examples 1-9, Comparative Examples 1-2)

[0132] In this embodiment, samples of toothbrushes of Examples 1 to 9 and Comparative Examples 1 to 2 were prepared according to the specifications shown in Table 1 below.

[0133] The dimensions of each part of the toothbrush in each example are shown in Table 1. The hard resin of the handle is made of polypropylene (PP) resin.

[0134] In Examples 1-9 and Comparative Examples 1-2, the maximum length of the head in the width direction was set to 15.0 mm, the length of the head in the thickness direction was set to a constant 3.0 mm, the maximum length of the neck in the width direction was set to 4.0 mm, and the maximum length of the neck in the thickness direction was set to 4.0 mm.

[0135] [Evaluation Method]

[0136] A panel of 10 professionals cleaned the oral cavity using samples of each toothbrush, evaluating the "ease of deflection in the width direction" and "feeling of thorough brushing without twisting" according to the following criteria. The evaluation was based on the average score from the 10-person professional panel. An average score of 5.5 or higher was designated "◎ (Very Good)", an average score of 4.0 or higher but less than 5.5 was designated "○ (Good)", an average score of 3.0 or higher but less than 4.0 was designated "△ (Not Bad)", and an average score less than 3.0 was designated "× (Bad)".

[0137] (1) Difficulty of deflection in the width direction

[0138] [Evaluation Criteria]

[0139] 7 points: Very difficult to bend.

[0140] 6 points: Quite difficult to bend.

[0141] 5 points: Slightly difficult to bend.

[0142] 4 points: I can't say for sure which one.

[0143] 3 points: Slightly easy to bend but tolerable.

[0144] 2 points: Quite easy to bend.

[0145] 1 point: Very easy to bend.

[0146] (2) A feeling of being able to brush thoroughly without distortion.

[0147] 7 points: It can be thoroughly cleaned without any distortion.

[0148] 6 points: It can brush thoroughly with almost no distortion.

[0149] 5 points: It can be thoroughly cleaned even when the surface is not too distorted.

[0150] 4 points: Both.

[0151] 3 points: Slightly distorted, cannot be fully cleaned, but acceptable.

[0152] 2 points: Quite distorted, cannot be thoroughly cleaned.

[0153] 1 point: Very distorted, cannot be thoroughly cleaned.

[0154] [Table 1]

[0155]

[0156] As shown in [Table 1], the toothbrush samples of Examples 1 to 9, which have a maximum head length of 12 mm or more and 18 mm or less in the width direction, a maximum head length of 2 mm or more and 4 mm or less in the thickness direction, a minimum neck length of 3 mm or more and 5 mm or less in the width direction and a minimum neck length of 3 mm or more and 5 mm or less in the thickness direction, satisfy the relationship (volume of region D) / (volume of region C) ≥ 1.0, and have a maximum width length greater than the maximum thickness length at the 4th position of the rear end of region D, received good evaluations in both "ease of bending in the width direction" and "feeling of being able to brush thoroughly without twisting".

[0157] Furthermore, in the toothbrush samples of Examples 3 to 4 and 9, which satisfy the relationship (volume of region A) / (volume of region D) ≤ 0.60, good evaluations were obtained in both aspects of "difficulty of bending in the width direction" and "feeling of being able to brush thoroughly without twisting".

[0158] Additionally, the volume of region D is 1000 mm². 3 The toothbrush samples of Examples 5-6 and 9 above received good evaluations in terms of both "ease of bending in the width direction" and "the feeling of being able to brush thoroughly without twisting".

[0159] Furthermore, in the toothbrush samples of Examples 2 to 7 and 9, which satisfy the relationship (the sum of the volumes of region A and region C) / (the sum of the volumes of region A, region B, region C, and region D) ≤ 0.70, good evaluations were obtained in both aspects of "difficulty of bending in the width direction" and "the feeling of being able to brush thoroughly without twisting".

[0160] Furthermore, in the toothbrush samples of Examples 8 to 9, which have a maximum length in the width direction of the 4th position of 11 mm or more and satisfy the relationship (maximum length in the width direction of the 4th position) - (maximum length in the thickness direction of the 4th position) ≥ 2 mm, both the "ease of bending in the width direction" and the "feeling of being able to brush thoroughly without twisting" were well evaluated.

[0161] Based on the above results, it can be seen that the toothbrush sample of Example 9 received particularly good evaluations in terms of "ease of bending in the width direction" and "the feeling of being able to brush thoroughly without twisting". Subsequently, the toothbrush samples of Examples 2 and 6 received even better evaluations.

[0162] On the other hand, in Comparative Example 1, where the relationship (volume of region D) / (volume of region C) ≥ 1.0 is not satisfied, and in Comparative Example 2, where the maximum length in the width direction at the fourth position (the rear end of region D) is less than the maximum length in the thickness direction, neither "ease of bending in the width direction" nor "the feeling of being able to brush thoroughly without twisting" can be well evaluated.

[0163] The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but it goes without saying that the present invention is not limited to the related examples. The various shapes and combinations of the constituent components shown in the above examples are just examples, and various modifications can be made according to design requirements, etc., without departing from the spirit of the present invention.

[0164] [Industry availability]

[0165] This invention can be applied to toothbrushes.

Claims

1. A toothbrush, characterized in that, It has: a head with a tufted surface located at the front end along the long axis. The grip portion is positioned further back than the head, and The neck is positioned between the head and the grip. The maximum length of the head in the width direction, which is parallel to the hair-planting surface and orthogonal to the long axis, is 12mm or more and 18mm or less. The maximum length of the head in the thickness direction orthogonal to the hair-planting surface is 2mm or more and 4mm or less. The minimum length of the neck in the width direction and the minimum length in the thickness direction are both 3 mm and less than 5 mm. In the head, region A is defined as the area extending along the long axis from the front end to the first position at the rearmost end where the length in the width direction is greatest, and region B is defined as the area extending from the first position to the second position at the boundary between the head and the neck. In the neck region, when region C extends from the second position to a third position (65% of the length relative to the major axis of the neck), and region D extends from the third position to a fourth position (35% of the length relative to the major axis of the neck) at the boundary between the neck and the grip, the relationship (volume of region D) / (volume of region C) ≥ 1.5 is satisfied. The increase in thickness in the region from the rearmost position where the length in the width direction of the neck is minimum to the end of the front end of the finger contact portion located on the hair-covered surface side of the gripping portion is greater than the increase in thickness from the boundary between the head and the neck to the rearmost position where the length in the width direction of the neck is minimum, and the increase in thickness ends at the end of the front end of the finger contact portion. At the fourth position, the maximum length in the width direction is greater than the maximum length in the thickness direction.

2. The toothbrush according to claim 1, wherein the relationship (volume of region A) / (volume of region D) ≤ 0.60 is satisfied.

3. The toothbrush according to claim 1 or 2, wherein, The volume of region D is 1000 mm². 3 above.

4. The toothbrush according to claim 1 or 2, wherein the relationship is satisfied that (the sum of the volumes of region A and region C) / (the sum of the volumes of region A, region B, region C and region D) ≤ 0.

70.

5. The toothbrush according to claim 1 or 2, wherein, The maximum length in the width direction at the fourth position is 11 mm or more. And it satisfies the relationship that (maximum length in the width direction at the fourth position) - (maximum length in the thickness direction at the fourth position) ≥ 2 mm.

6. The toothbrush according to claim 1 or 2, wherein the relationship is 1.5mm ≤ (maximum length in the width direction of the region A) - (maximum length in the width direction at the fourth position) ≤ 7mm.

7. The toothbrush according to claim 1 or 2, wherein the relationship is satisfied that (maximum length in the thickness direction at the fourth position) - (maximum length in the thickness direction at the third position) ≥ 3 mm.

8. The toothbrush according to claim 1 or 2, wherein the relationship is satisfied that (the maximum length in the thickness direction at the third position) - (the average length in the thickness direction of the region A along the longitudinal axis) ≤ 2 mm.

9. The toothbrush according to claim 1 or 2, wherein, The maximum length of the thickness direction running through the major axis in region C is less than 4.5 mm. The relationship is satisfied that (maximum length in the width direction at the third position) - (maximum length in the thickness direction at the third position) > 1 mm.

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