Toothbrush

Abstract

The utility model provides a toothbrush which solves the problems of controlling the bending direction of a neck part and the holding property of a holding part and improves the operability during brushing. The toothbrush includes a brush body including: a head portion disposed on a distal end side in a longitudinal axis direction and having a bristle planting surface; a neck portion disposed on a rear end side of the head portion; and a grip part disposed on the rear end side of the neck part, the neck part being a linear shape having a wide width and a substantially quadrilateral cross-sectional shape, the length D1 and the length W1 being constant values when the length of the neck part in the thickness direction is D1 and the length of the neck part in the width direction is W1, the length W1 and the length D1 satisfying the relationship W1 > D1, and the grip part extending in the longitudinal direction. A transition portion is provided between the neck portion and the grip portion, the length of the transition portion in the width direction and the length of the transition portion in the thickness direction increase from the neck portion toward the grip portion, and the transition portion has a second crest line extending continuously to the tip side with a first crest line formed on the outer peripheral surface of the grip portion.

Description

Technical Field

[0001] The utility model relates to a toothbrush. Background Art

[0002] During the brushing process, it is required to improve the operability of the toothbrush and control the direction of bending. Currently, in order to improve the usability, toothbrushes with thin necks are circulated on the market. If the shape is particularly focused, most of the necks are set to a horizontally flat shape that is flat in the width direction.

[0003] Toothbrushes with a laterally flattened neck can bend easily during brushing, improving usability. On the other hand, when the brush portion of such a toothbrush is brought into contact with the teeth at an angle, the toothbrush may twist in the torque direction of the head (circumferential direction centered on the long axis), resulting in poor usability due to the neck flexing not only perpendicularly to the teeth but also in all directions and angles.

[0004] The toothbrush disclosed in Patent Document 1 has a thinner neck to improve operability in the oral cavity. By gradually changing the cross-sectional shape of the neck to a specific shape as it moves from the head toward the grip, the deflection of the thin neck can be controlled, allowing brushing with appropriate brushing pressure.

[0005] In addition, regarding the operability of a toothbrush, the ease of holding the grip is also important. For example, the toothbrush disclosed in Patent Document 2 improves the ease of holding and use by changing the cross-sectional shape of the grip from the front end to the rear end.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent No. 5806922

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 2000-262329 Utility Model Content

[0010] Technical problems to be solved by utility models

[0011] The toothbrush of Patent Document 1 controls the degree of deflection of the neck by changing the cross-sectional shape of the neck in stages. However, the control of the deflection direction is not considered, and there is room for improvement in operability.

[0012] Since the cross-sectional shape of the grip portion of the toothbrush disclosed in Patent Document 2 changes from the front end to the rear end, the gripping method and the force used to hold the grip portion change depending on the longitudinal position of the grip portion, making it difficult to always apply uniform brushing pressure to the teeth.

[0013] At least one embodiment of the present invention is completed in view of the above situation. Specifically, the present invention provides a toothbrush that solves the problem of controlling the bending direction of the neck and the problem of the gripping property of the gripping portion, thereby improving the operability during brushing.

[0014] Technical solutions to problems

[0015] The above-mentioned object of the present invention is achieved by any one of the following (1) to (6).

[0016] (1) A toothbrush having a brush body, the brush body comprising: a head, which is arranged on the front end side in the longitudinal direction and has a hair-planted surface; a neck, which is arranged on the side closer to the rear end than the head; and a gripping portion, which is arranged on the side closer to the rear end than the neck, the neck being a straight line having a wide, approximately quadrilateral cross-sectional shape, and when the length of the neck in the thickness direction is set to D1 and the length in the width direction is set to W1, the length D1 and the length W1 are constant values, and extend in the longitudinal direction so as to satisfy the relationship between the length W1 and the length D1 being W1>D1, and a transition portion is provided between the neck and the gripping portion, the length of the transition portion in the width direction and the length in the thickness direction increasing from the neck toward the gripping portion, and the transition portion having a second ridge, the second ridge extending continuously toward the front end side with any one of the first ridges formed on the outer peripheral surface of the gripping portion.

[0017] (2) The toothbrush according to (1) above, wherein a ratio W1 / D1 of the length W1 to the length D1 of the neck portion is 1.25 or greater.

[0018] (3) A toothbrush according to (1) or (2) above, wherein the cross-sectional shape of the holding portion is a polygon larger than a hexagon, extending straight along the long axis direction from the front end to the base end with the same cross-sectional shape, and among the multiple peripheral surfaces that divide the polygon, the first peripheral surface located on the surface and the second peripheral surface located on the back side opposite to the first peripheral surface are parallel to the hair-planted surface of the head and the bottom surface of the head opposite to the hair-planted surface, and the third ridge that becomes the contour line of the neck when viewed from above and above is connected to the first ridge of the peripheral surface forming the holding portion with the same width.

[0019] (4) A toothbrush according to any one of (1) to (3) above, wherein, when the length of the neck in the longitudinal direction is L1 and the length of the transition portion in the longitudinal direction is L2, a ratio L2 / L1 of the length L2 to the length L1 is less than 0.75.

[0020] (5) A toothbrush according to any one of (1) to (4) above, wherein the length D1 is greater than or equal to 2.5 mm and less than or equal to 3.8 mm, the length D2 which becomes the maximum thickness of the head is greater than or equal to 2.0 mm and less than or equal to 3.5 mm, and the head and the neck are arranged so as to overlap with the extension line of the line segment A1 connecting the midpoint of the thickness direction of the gripping portion when viewed from the front.

[0021] (6) The toothbrush according to any one of (1) to (5) above, wherein the brush body is formed of only one type of hard resin.

[0022] Utility model effect

[0023] The toothbrush of the present invention allows the neck to bend easily in the thickness direction. Furthermore, since the neck's bending point can be positioned within the range from the rear end (grip portion) to the transition portion, twisting of the head 10 in the torque direction can be suppressed. Consequently, the toothbrush of the present invention can apply appropriate force to the teeth during brushing, improving usability. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a plane side stereogram of the toothbrush of the present invention.

[0025] Figure 2 It is a bottom side perspective view of the toothbrush of the present invention.

[0026] Figure 3 It is a front view of the toothbrush of the present invention.

[0027] Figure 4 It is a rear view of the toothbrush of the present invention.

[0028] Figure 5 It is a top view of the toothbrush of the present invention.

[0029] Figure 6 It is a bottom view of the toothbrush of the present invention.

[0030] Figure 7 It is a left side view of the toothbrush of the present invention.

[0031] Figure 8 It is a right side view of the toothbrush of the present invention.

[0032] exist Figure 9 middle, Figure 9 (a) is a partial enlarged view of the toothbrush of the present invention from the head to the periphery of the front end side of the grip portion when viewed from above, Figure 9 (b) is a partially enlarged view of the toothbrush of the present invention from the head to the periphery of the front end side of the grip portion when viewed from bottom.

[0033] Figure 10This is a partially enlarged front view of the toothbrush of the present invention, from the head to the periphery of the front end side of the grip portion.

[0034] Figure 11 This is a diagram showing boundaries P1 to P3 and line segment A1 of the toothbrush of the present invention.

[0035] Figure 12 It is an AA cross-sectional view of the toothbrush of the present invention.

[0036] Figure 13 It is a BB cross-sectional view of the toothbrush of the present invention.

[0037] Figure 14 It is a CC cross-sectional view of the toothbrush of the present invention. DETAILED DESCRIPTION

[0038] Hereinafter, the method for implementing the present invention will be described in detail with reference to the accompanying drawings. The embodiments shown here are for the purpose of exemplifying the technical concept of the present invention and are not intended to limit the embodiments of the present invention. In addition, other methods, embodiments, and application technologies that can be considered by those skilled in the art without departing from the scope of the present invention are all included in the scope and purpose of the present invention, and are included in the scope of the utility model and its equivalents as described in the scope of the patent claims.

[0039] Furthermore, for the sake of convenience and easy understanding, the drawings attached to this specification may be schematically expressed with appropriate scales, aspect ratios, shapes, etc. changed from the actual objects, but this is only an example and does not limit the interpretation of the present invention.

[0040] The arrows X1-X2 forming the X-axis in each figure indicate the longitudinal direction of the toothbrush 100. The arrow X1 indicates the front end (head 10 side) of the toothbrush 100, and the arrow X2 indicates the rear end (grip 30 side) of the toothbrush 100. Furthermore, the arrows Y1-Y2 forming the Y-axis in each figure indicate the width direction of the toothbrush 100. Furthermore, the arrows Z1-Z2 forming the Z-axis in each figure indicate the thickness direction of the toothbrush 100.

[0041] In this specification, a top view refers to observing the toothbrush 100 from the side of the hair-planting surface 11 of the head 10, and a bottom view refers to observing the toothbrush 100 from the side opposite to the hair-planting surface 11 of the head 10 (see FIG. Figure 5 、 Figure 6 The front view refers to the view from a direction perpendicular to the thickness direction of the head 10 (see Figure 3 ). Figure 4 The rear view shown is the same as Figure 3 The front views shown are represented symmetrically.

[0042] In addition, the "surface" of the holding portion 30 refers to the surface of the head 10 that faces in the same direction as the hair-implanted surface 11 on which the hair bundles 13 are implanted, the "back surface" refers to the surface on the opposite side of the "surface", and the "side surface" refers to the surface other than the "surface", the "back surface" and the surface on the base end side.

[0043] Appropriate reference Figures 1 to 14 The toothbrush 100 according to this embodiment will be described.

[0044] Figures 1 to 8 The shape of the toothbrush 100 of this embodiment is shown. Figure 1 This is a perspective view of the toothbrush 100 as viewed from the flat side (flat side perspective view). Figure 2 This is a perspective view of the toothbrush 100 as viewed from the bottom side (bottom side perspective view). Figure 3 This is a front view of the toothbrush 100 (front view). Figure 4 1 is a rear view of the toothbrush 100 (rear view). Figure 5 This is a diagram (top view) of the toothbrush 100 viewed from above. Figure 6 This is a diagram looking up at the toothbrush 100 (bottom view). Figure 7 This is a diagram of the toothbrush 100 viewed from the left (left side view). Figure 8 This is a diagram (right side view) of the toothbrush 100 as viewed from the right side.

[0045] like Figures 1 to 8 As shown in any of the figures, the toothbrush 100 includes a head 10, which is arranged at the front end in the longitudinal direction and has a hair-planted surface 11 with bristle bundles 13 implanted therein; a neck 20, which is arranged on the rear side of the head 10; a grip 30, which is arranged on the rear side of the neck 20; and a transition portion 40, which is arranged between the neck 20 and the grip 30. The toothbrush 100 includes a brush body 110 having the head 10, the neck 20, the grip 30, and the transition portion 40.

[0046] The brush body 110 is integrally formed into a long strip and can be formed using a hard resin. As the hard resin constituting the brush body 110, for example, polypropylene (PP), polyacetal (POM), polyethylene terephthalate (PCT), polyethylene terephthalate (PET), polycarbonate (PC), polymethyl methacrylate (PMMA), polystyrene (PS), acrylonitrile-butadiene-styrene resin (ABS), cellulose propionate (CP), polyarylate, etc. can be used. In addition, the above-mentioned hard resins can also be biodegradable resins, plant-derived resins, paper mixed resins, plant mixed resins, etc. Among these resins, polypropylene resin (PP) is preferably used as a resin that is soft and flexible and has low breakability as a resin that more significantly achieves the effect of the utility model.

[0047] Here, when a soft resin or a soft resin coating is used as the forming material of the brush body 110, the shape of the gripping portion 30 changes when gripping, so it is not necessarily possible to grip in the same way. In addition, when the brush body 110 is secondary molded, the desired torsion control and flexure control cannot be achieved. In contrast, if polypropylene resin (PP) is used as the forming material of the brush body 110, appropriate flexure and torsion suppression can be achieved. In addition, no matter at which angle the toothbrush 100 is gripped, it can be gripped at the same angle and with the same force, so the toothbrush 100 has excellent operability. Therefore, it is more preferable that polypropylene (PP) is used as the hard resin constituting the brush body 110.

[0048] In addition, it is preferable that the entire brush body 110 is formed of the same hard resin. If the brush body 110 is formed of a common hard resin, the force applied to the grip 30 can be appropriately transmitted to the head 10.

[0049] In the present embodiment, the boundary P1 between the head 10 and the neck 20 , the boundary P2 between the neck 20 and the transition portion 40 , and the boundary P3 between the transition portion 40 and the grip portion 30 are defined as follows.

[0050] The boundary P1 between the head 10 and the neck 20 is as follows: Figure 5 、 Figure 9 As shown, it is the position where the width of the head 10 in the top view is reduced, or as shown in FIG. Figure 11 , which is the end point of the thickness expansion of the head 10 in the front view. However, regarding the boundary P1, if the positions of the aforementioned end points are offset in the longitudinal direction, the position of the end point closer to the grip 30 side is set as the boundary position.

[0051] The boundary P2 between the neck portion 20 and the transition portion 40 is as shown in FIG. Figure 5 、 Figure 9 As shown, it is the position of the starting point of the width expansion of the transition portion 40 in the top view, or as shown in FIG. Figure 11 , which is the position of the starting point of the thickness expansion of the transition portion 40 in the front view. However, regarding the boundary P2, if the positions of the aforementioned starting points are offset in the longitudinal direction, the position of the starting point closer to the head 20 side is set as the boundary position.

[0052] The boundary P3 between the transition portion 40 and the grip portion 30 is as shown in FIG. Figure 5 、 Figure 9 As shown, it is the position of the end point of the width expansion of the transition portion 40 in the top view, or as shown in FIG. Figure 11, is the position of the end point of the thickness expansion of the transition portion 40 in the front view. However, regarding the boundary P3, if the positions of the aforementioned end points are offset in the longitudinal direction, the position of the end point closer to the grip portion 30 is set as the boundary position.

[0053] <Head>

[0054] The head 10 is located at the front end of the toothbrush 100 and is integrally connected to the neck 20. The head 10 has a bristle-implanted surface 11 on one side in the thickness direction. The bristle-implanted surface 11 has a plurality of bristle-implanted holes 12, each of which contains bristle bundles 13. The plurality of bristle bundles 13 constitute a brush portion 14. The toothbrush 100 can clean the oral cavity using the brush portion 14 of the head 10.

[0055] The material of the bristles constituting the tufts 13, the number of bristles in each tuft 13, the number of tufts 13, etc. can be arbitrarily selected. Examples of the shape of the bristles include bristles whose diameter gradually decreases toward the bristle tip and whose bristle tips are sharpened (tapered bristles), and bristles whose diameters are roughly the same from the bristle-planting surface 11 toward the bristle tip (straight bristles). Examples of straight bristles include straight bristles whose bristle tips are set to a plane roughly parallel to the bristle-planting surface 11, and straight bristles whose bristle tips are rounded into a hemispherical shape. The cross-sectional shape of the bristles is not particularly limited and can be set to a circle such as a perfect circle, an ellipse, a polygon, a star, a clover, a four-leaf clover, etc. The cross-sectional shapes of all the bristles can be the same or different.

[0056] like Figure 9 As shown, the length D2 at which the head 10 has the minimum thickness can be defined as the thickness of the head 10 at the position where the thickness of the head 10 is the minimum in the Z-axis direction. The lower limit of the length D2 at which the head 10 has the minimum thickness is preferably 2.0 mm or greater. The upper limit of the length D2 is preferably 3.5 mm or less.

[0057] like Figure 10 As shown, the length W2 that represents the maximum width of the head 10 can be defined as the width of the head 10 at the position where the width of the head 10 is the largest in the Y-axis direction. The lower limit of the length W2 is preferably 10.0 mm or greater. The upper limit of the length W2 is preferably 15.0 mm or less.

[0058] The head 10 preferably has a rib 15 on the bottom surface 16 at the rear end, and can have a continuous shape with a thickness varying from a length D1 that is the minimum thickness of the head 10 to a length D2 that is the thickness of the neck 20 .

[0059] Preferably, if Figure 11As shown, the head 10 is arranged so that, when viewed from the front (and rear), the head 10 and neck 20 overlap with the extension of line segment A1 connecting the midpoints of the grip 30 in the thickness direction. This facilitates the coordinated movement of the hand and the movement of the head 10 and neck 20 when the toothbrush 100 is rotated in the torque direction relative to the long axis of the grip 30. This allows the toothbrush 100 to fit the tooth surface at an appropriate angle, thereby suppressing twisting of the head 10 in the torque direction.

[0060] Neck

[0061] The front end of the neck 20 is adjacent to the base end of the head 10, and the base end of the neck 20 is adjacent to the front end of the transition portion 40. The neck 20 is formed into a straight line shape with a generally square cross-section that is wide and flat (transversely flat). The term "generally square" refers to a shape with an angle R of 5.0 or less.

[0062] Figure 12 : is a cross-sectional view of the boundary P1 between the head 10 and the neck 20. Figure 12 As shown, the length D1 of the neck 20 in the thickness direction can be defined as the thickness of the neck 20 in the Z-axis direction. The lower limit of the length D1 is preferably 2.5 mm or more, and the upper limit of the length D1 is preferably 3.8 mm or less.

[0063] like Figure 12 As shown, the widthwise length W1 of the neck portion 20 can be defined as the width of the neck portion 20 in the Y-axis direction. The lower limit of the length W1 is preferably 4.8 mm or greater, and the upper limit of the length W1 is preferably 6.0 mm or less.

[0064] like Figure 9 As shown, the length L1 of the neck 20 in the longitudinal direction can be defined as the entire length of the neck 20 in the X-axis direction. The lower limit of the length L1 is preferably 30.0 mm or more, and the upper limit of the length L1 is preferably 35.0 mm or less.

[0065] like Figure 12 As shown, when the neck 20 has a thickness length D1 and a width length W1, both lengths D1 and W1 remain constant, satisfying the relationship W1 > D1, and extend along the longitudinal direction. Furthermore, "constant" means that both lengths D1 and W1 are within ±0.5 mm, or W1 / D1 is ±0.1.

[0066] The cross-sectional shape of the neck 20 of the toothbrush 100 of this embodiment has a horizontally long and flat, roughly quadrilateral cross-sectional shape, and the length D1 and the length W1 are constant values, and satisfy the relationship W1>D1, extending from the base end of the head 10 toward the grip 30 along the longitudinal direction. As a result, the neck 20 is easily bent in the thickness direction. In addition, since the position of the bending point of the neck 20 can be located within the range from the rear end side (the grip 30 side) to the transition portion 40, the twisting of the head 10 in the torque direction can be suppressed. Therefore, the toothbrush 100 can apply appropriate force to the teeth during brushing, improving usability.

[0067] The ratio W1 / D1 of the length D1 in the thickness direction of the neck portion 20 to the length W1 in the width direction is 1.25 or greater.

[0068] In a toothbrush, if the ratio of the neck's width to its thickness is less than 1.25, the neck's flexibility becomes limited, potentially reducing usability. In contrast, the toothbrush 100 of this embodiment extends the neck 20 in a straight line along the longitudinal axis with W1 / D1 ≥ 1.25, making it easier to flex in the thickness direction of the neck 20 and improving usability.

[0069] like Figure 9 As shown in (a) and (b), the third ridge 21, which forms the outline of the neck 20 when viewed from above and below, is connected to the first ridge 33 forming the outer peripheral surface of the grip portion 30 with the same width. The third ridge 21 is connected to the first ridge 33 of the first outer peripheral surface 31 that defines the front surface of the grip portion 30 and the first ridge 33 of the second outer peripheral surface 32 that defines the back surface of the grip portion 30 with the same width. Figure 9 As shown in (a) and (b), the first ridge 33 and the third ridge 21 are continuously connected via the second ridge 41 formed on the front and back sides of the transition portion 40. Here, "connected with the same width" is not limited to a state where the width direction length of the third ridge 21, which forms the outline of the neck 20, the width direction length of the first ridge 33 dividing the first outer peripheral surface 31 of the grip portion 30, and the width direction length of the first ridge 33 dividing the second outer peripheral surface 32 of the grip portion 30 are the same, but also includes a state where the width direction difference is within 1 mm.

[0070] Thus, the toothbrush 100 suppresses twisting of the head 10 in the torque direction, and the bending direction of the neck 20 is easily limited to the thickness direction.

[0071] <Grip>

[0072] The front end of the grip portion 30 is disposed adjacent to the base end of the transition portion 40. The grip portion 30 is gripped by the user with fingers or the like when cleaning (brushing) the oral cavity.

[0073] The grip portion 30 has a linear shape with a roughly polygonal cross-section that is larger than a hexagon. The cross-section of the grip portion 30 extends uniformly from the distal end to the proximal end. Furthermore, to facilitate gripping, some of the corners of the polygonal cross-section of the grip portion 30 may be rounded.

[0074] Figure 13 is a cross-sectional view of the rear end side of the grip portion 30, Figure 14 : is a cross-sectional view of the boundary P3 between the grip portion 30 and the transition portion 40. Figure 13 、 Figure 14 As shown, the grip portion 30 of this embodiment is a configuration in which the curvature radius of the corner R on the back side slightly changes between the front end side and the rear end side. Figure 13 、 Figure 14 As shown, the length D3 of the grip portion 30 in the thickness direction can be defined as the thickness of the grip portion 30 in the Z-axis direction. The lower limit of the length D3 is preferably 7.0 mm or more, and the upper limit of the length D3 is preferably 12.0 mm or less.

[0075] like Figure 13 、 Figure 14 As shown, the widthwise length W3 of the gripping portion 30 can be defined as the width of the gripping portion 30 in the Y-axis direction. The lower limit of the length W3 is preferably 7.0 mm or more, and the upper limit of the length W3 is preferably 12.0 mm or less.

[0076] The gripping portion 30 has multiple outer peripheral surfaces that are divided into polygonal cross-sectional shapes. Each outer peripheral surface is divided by multiple first ridges 33 arranged in the circumferential direction of the gripping portion 30. In the gripping portion 30, among the multiple outer peripheral surfaces that are divided into polygonal cross-sectional shapes, the first outer peripheral surface 31 located on the front surface and the second outer peripheral surface 32 located on the back surface opposite to the first outer peripheral surface 31 are parallel to the hair-implanted surface 11 of the head 10 and the bottom surface 16 of the head 10 opposite to the hair-implanted surface 11.

[0077] The cross-sectional shape of the grip portion 30 is a polygon larger than a hexagon, extending straight from the front end to the base end with the same cross-sectional shape. Furthermore, because the first and second outer peripheral surfaces 31, 32 are parallel to the hair-planted surface 11 and bottom surface 16 of the head 10, the gripping method remains unchanged regardless of where the grip portion 30 is gripped along its length, making it easy to apply force in the thickness direction of the hair-planted surface 11. Furthermore, when the grip portion 30 is rotated in the direction of torque relative to the longitudinal axis, the grip portion 30 can be gripped in the same manner, resulting in good operability. Therefore, the toothbrush 100 can achieve appropriate neck flexure and uniform brushing.

[0078] The gripping portion 30 may be provided with an anti-slip portion 50 on at least a portion of the outer peripheral surface. Figure 1 As shown in FIG, etc., the anti-slip portion 50 can be formed by arranging multiple creped areas in parallel along the longitudinal direction. The anti-slip portion 50 is preferably formed in the neck-side area of ​​the surface and back of the grip 30 (the area on the front side of the grip 30). As a result, when the user grasps the grip 30 with the palm of their hand, the thumb, index finger, etc. come into contact with the anti-slip portion 50, allowing the grip 30 to be grasped and the force applied to the grip 30 to be effectively transmitted to the teeth. Furthermore, there are no particular limitations on the shape, location, and material of the anti-slip portion 50, as long as the user can obtain an anti-slip function through contact with the fingers when grasping the grip 30.

[0079] <Transition section>

[0080] The front end of the transition portion 40 is adjacent to the base end of the neck 20, and the base end is adjacent to the front end of the grip 30. In the toothbrush 100, the transition portion 40 connects the neck 20 and the grip 30. The transition portion 40 increases in width and thickness along its longitudinal axis from the neck 20 toward the grip 30.

[0081] like Figure 9 As shown, the length L2 of the transition portion 40 in the longitudinal direction can be defined as the entire length of the transition portion 40 in the X-axis direction. The lower limit of the length L2 is preferably 17.0 mm or more, and the upper limit of the length L2 is preferably 22.0 mm or less.

[0082] The ratio L2 / L1 of the length L2 of the transition portion 40 in the longitudinal direction to the length L1 of the neck portion 20 in the longitudinal direction is less than 0.75. The lower limit of L2 / L1 is preferably greater than 0.45.

[0083] In a toothbrush, if the ratio of the length of the neck in the longitudinal direction to the length of the transition section in the longitudinal direction is greater than 0.75, the length of the neck that can be properly flexed becomes shorter, thereby reducing the flexibility of the neck and potentially reducing usability. Furthermore, if the ratio of the length of the neck in the longitudinal direction to the length of the transition section in the longitudinal direction is less than 0.45, the strength of the neck may not be guaranteed due to stress concentration. In contrast, in the toothbrush 100 of this embodiment, the ratio L2 / L1 of the length L2 of the transition section 40 in the longitudinal direction to the length L1 of the neck 20 in the longitudinal direction is less than 0.75. Therefore, the neck 20 of the toothbrush 100 easily flexes in the thickness direction of the neck 20, improving usability.

[0084] The transition portion 40 has a second ridge 41, and the second ridge 41 extends continuously toward the front end side with the first ridge 33 formed on the outer peripheral surface of the grip portion 30. Figure 10 As shown, the second ridge 41 is continuous with the first ridge 33 that divides the outer peripheral surface forming the side surface of the grip portion 30 and is located on the side surface of the grip portion 30 .

[0085] The cross-sectional shape of the neck 20 of the toothbrush 100 of this embodiment has a horizontally long and flat, roughly quadrilateral cross-sectional shape, and the length D1 and the length W1 are constant values, and satisfy the relationship W1>D1. It extends from the base end of the head 10 toward the grip 30 along the longitudinal direction. Furthermore, the transition portion 40 has a second edge 41 that is continuous with the first edge 33 of the grip 30. As a result, the neck 20 is easily bent in the thickness direction. In addition, since the position of the bending point of the neck 20 can be located within the range from the rear end side (grip 30 side) to the transition portion 40, the twisting of the head 10 in the torque direction can be suppressed. Therefore, the toothbrush 100 can apply appropriate force to the teeth during brushing, and the usability is improved.

[0086] The toothbrush 100 of this embodiment features the shape of the brush body 110 in that the neck 20 is horizontally flat, the cross-sectional shape extends straight along the longitudinal axis with a uniform shape, and the transition portion 40 is short. Conventional toothbrushes have necks with a uniform cross-sectional shape, not a straight line, but rather an R-shaped curve. This is done to achieve an S-shaped neck that follows the teeth or to ensure strength. However, toothbrushes with an S-shaped neck often have a roughly circular cross-sectional shape, which does not adequately ensure neck flexibility and cannot control torsion of the head in the direction of torque, potentially causing twisting. In contrast, the toothbrush 100 of this embodiment adopts a horizontally flat, straight, uniform cross-sectional shape to facilitate flexibility in the thickness direction. However, simply by making the neck 20 a horizontally flat, uniform, straight line, it is difficult to suppress torsion of the head 10 in the direction of torque. Therefore, the toothbrush 100 suppresses the torsion of the head 10 in the torque direction by adopting a new shape such as "setting the straight portion of the neck 20 to be long so that the bending point is located as close to the rear end of the neck 20 as possible" and "configuring a transition portion 40 from the neck 20 to the holding portion 30 at the bending point near the rear end of the neck 20, and providing a strong ridge from the neck 20 to the holding portion 30 (that is, the first ridge 33 of the holding portion 30 and the third ridge 21 of the neck 20 are connected with the same width, and a second ridge 41 continuous with the first ridge 33 is provided, etc.)".

[0087] As described above, the toothbrush 100 of this embodiment has a brush body 110, which includes: a head 10, which is arranged on the front end side in the longitudinal direction and has a hair-planted surface 11; a neck 20, which is arranged on the rear end side of the head 10; and a grip portion 30, which is arranged on the rear end side of the neck 20. The neck 20 is a straight line shape with a wide, substantially quadrilateral cross-sectional shape. When the length of the neck 20 in the thickness direction is D1 and the length in the width direction is W1, the length D1 and the length W1 are constant values, and the length W1 and the length D1 satisfy the relationship W1>D1 and extend in the longitudinal direction. A transition portion 40 is provided between the neck 20 and the grip portion 30. The length of the transition portion 40 in the width direction and the length in the thickness direction increase from the neck 20 toward the grip portion 30. The transition portion 40 has a second ridge 41, and the second ridge 41 extends toward the front end continuously with the first ridge 33 formed on the outer peripheral surface of the grip portion 30.

[0088] This structure allows the neck 20 of the toothbrush 100 of this embodiment to bend easily in the thickness direction. Furthermore, since the bending point of the neck 20 can be positioned within the range from the rear end (the grip 30 side) to the transition portion 40, twisting of the head 10 in the torque direction can be suppressed. Consequently, the toothbrush 100 can apply an appropriate force to the teeth during brushing, improving usability.

[0089] Description of Reference Numerals

[0090] 10 Head

[0091] 11 Hair transplanted surface

[0092] 12 Pore transplantation

[0093] 13 hair bundles

[0094] 14 Brush

[0095] 15 ribs

[0096] 16 Bottom of the head

[0097] 20 Neck

[0098] 21 Third Ridge

[0099] 30 grip

[0100] 31 First outer peripheral surface

[0101] 32 Second outer surface

[0102] 33 First Ridge

[0103] 40 Transition

[0104] 41 Second Ridge

[0105] 50 Anti-slip part

[0106] 100 toothbrush

[0107] 110 Brush Body

[0108] A1 Line segment connecting the midpoints of the grip in the thickness direction

[0109] D1 Length of the neck in the thickness direction

[0110] D2 Minimum thickness of the head

[0111] D3 Maximum thickness of the grip

[0112] P1 Boundary between head and neck

[0113] P2 Boundary between neck and transition

[0114] P3 Boundary between transition part and grip part

[0115] L1: Length of the neck in the long axis direction

[0116] L2 The length of the transition portion in the long axis direction

[0117] W1 Length of the neck in width direction

[0118] W2 Maximum width of the head

[0119] W3 is the maximum width of the grip.

Claims

1. A toothbrush, characterized in that: The toothbrush has a brush body, which includes: a head, which is arranged on the front end side in the long axis direction and has a hair-planting surface; a neck, which is arranged on the side closer to the rear end than the head; and a grip, which is arranged on the side closer to the rear end than the neck. The neck is a straight line having a wide, substantially quadrilateral cross-sectional shape. When the length of the neck in the thickness direction is D1 and the length in the width direction is W1, the length D1 and the length W1 are constant values, and the length W1 and the length D1 satisfy the relationship of W1>D1 and extend in the long axis direction. A transition portion is provided between the neck and the grip portion, wherein the length in the width direction and the length in the thickness direction of the transition portion increase from the neck toward the grip portion. The transition portion has a second ridge that extends toward the distal end continuously with a first ridge formed on the outer peripheral surface of the grip portion.

2. The toothbrush according to claim 1, wherein A ratio W1 / D1 of the length W1 to the length D1 of the neck portion is greater than or equal to 1.

25.

3. The toothbrush according to claim 1, wherein The cross-sectional shape of the grip portion is a polygon larger than a hexagon, and extends straight along the longitudinal direction with the same cross-sectional shape from the front end to the base end. Among the plurality of peripheral surfaces that form the polygon, a first peripheral surface located on the surface and a second peripheral surface located on the back side opposite to the first peripheral surface are parallel to the hair-planting surface of the head and the bottom surface of the head opposite to the hair-planting surface. The third ridge that forms the outline of the neck in a plan view and a bottom view is connected to the first ridge that forms the outer peripheral surface of the grip portion at the same width.

4. The toothbrush according to claim 1, wherein When the length of the neck portion in the longitudinal direction is L1 and the length of the transition portion in the longitudinal direction is L2, a ratio L2 / L1 of the length L2 to the length L1 is less than 0.

75.

5. The toothbrush according to claim 1, wherein The length D1 is greater than or equal to 2.5 mm and less than or equal to 3.8 mm. The length D2 of the maximum thickness of the head is 2.0 mm or more and 3.5 mm or less. The head and the neck are arranged so as to overlap with an extension line of a line segment A1 connecting midpoints in the thickness direction of the grip portion in a front view.

6. The toothbrush according to claim 1, wherein The brush body is formed of only one hard resin.

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