Toothbrush

Abstract

To solve a problem on control of a bending direction of a neck part and gripping performance of a grip part, and improve operability in brushing.SOLUTION: A toothbrush 100 includes a brush body 110 including a head part 10 having a bristle-implanted surface 11 arranged on the tip side in a long axis direction, a neck part 20 arranged on a rear end side of the head part 10, and a grip part 30 arranged on the rear end side of the neck part 20. The neck part 20 has a straight shape having a wide roughly square cross-sectional shape, and extends in the long axis direction with the length D1 and the length W1 being constant values when the length in a thickness direction of the neck part 20 is represented as D1 and the length in a width direction is represented as W1, and the length W1 and the length D1 satisfying the relationship of W1>D1. There is a transition part 40 between the neck part 20 and the grip part 30 where the length in the width direction and the length in the thickness direction increase from the neck part 20 to the grip part 30. The transition part 40 includes a second ridge line 41 continued to a first ridge line 33 formed in the outer peripheral surface of the grip part 30, which extends to the tip side.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a toothbrush.

Background Art

[0002] In toothbrushing behavior, improvement in the operability of the toothbrush and control of the deflection direction are required. Currently, in order to improve usability, toothbrushes with thin necks are on the market. In particular, focusing on the shape, many have a horizontally flattened shape in the width direction for the shape of the neck portion.

[0003] For a toothbrush with a horizontally flattened neck portion, the neck portion is likely to deflect during brushing, and usability can be improved. On the other hand, for this type of toothbrush, when the brush portion is applied to the teeth at an angle from an oblique direction, the toothbrush may twist in the torque direction (circumferential direction centered on the long axis direction) of the head portion, and there is a problem that the neck portion deflects in all directions and angles with respect to the teeth, resulting in poor operability.

[0004] The toothbrush disclosed in Patent Document 1 aims to improve the operability in the oral cavity by making the neck portion thinner, and by gradually changing the cross-sectional shape of the neck portion into a specific shape from the head portion toward the gripping portion, it controls the degree of deflection in the thin neck portion and enables brushing with an appropriate brushing pressure.

[0005] Also, the operability of the toothbrush is also important in terms of the ease of holding the gripping portion. For example, the toothbrush disclosed in Patent Document 2 aims to improve the ease of holding and usability by changing the cross-sectional shape of the gripping portion from the tip to the rear end.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] The toothbrush of Patent Document 1 controls the deflection degree of the neck portion by changing the cross-sectional shape of the neck portion step by step, but the control of the deflection direction is not considered, and there is room for improvement in terms of operability.

[0008] In the toothbrush of Patent Document 2, since the cross-sectional shape of the grip portion changes from the tip to the rear end, the way of holding and the force for gripping the grip portion change depending on the position in the longitudinal direction having the grip portion, and it is difficult to always apply a uniform brushing pressure to the teeth.

[0009] At least one embodiment of the present invention has been made in view of the above circumstances. Specifically, it is to provide a toothbrush that can solve the control of the deflection direction of the neck portion and the gripability of the grip portion, and improve the operability during brushing.

Means for Solving the Problems

[0010] The above object of the present invention is achieved by any one of the following (1) to (6).

[0011] (1) A brush body including a head portion having a bristle surface disposed on the tip side in the major axis direction, a neck portion disposed on the rear end side of the head portion, and a grip portion disposed on the rear end side of the neck portion, wherein the neck portion has a straight shape with a substantially rectangular cross-sectional shape that is wide, and when the length in the thickness direction of the neck portion 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 major axis direction, and between the neck portion and the grip portion, there is a transition portion where the length in the width direction and the length in the thickness direction increase from the neck portion toward the grip portion, and the transition portion has a second ridge line that is continuous with any first ridge line formed on the outer peripheral surface of the grip portion and extends toward the tip side. Toothbrush.

[0012] (2) The neck portion has a ratio of the length W1 to the length D1, i.e., W1 / D1, of 1.25 or more. The toothbrush according to (1) above.

[0013] (3) The gripping portion has a cross-sectional shape that is a polygon with six or more sides, extends straight in the major axis direction with the same cross-sectional shape from the tip to the base end, and among the plurality of outer peripheral surfaces that define the polygon, the first outer peripheral surface located on the surface and the second outer peripheral surface located on the back surface opposite to the first outer peripheral surface are parallel to the bristle surface of the head portion and the bottom surface of the head portion opposite to the bristle surface, and the third ridge line that becomes the contour line in the plan view and bottom view of the neck portion is connected with the same width as the first ridge line that forms the outer peripheral surface of the gripping portion. The toothbrush according to (1) or (2) above.

[0014] (4) When the length of the neck portion in the major axis direction is L1 and the length of the transition portion in the major axis direction is L2, the ratio of the length L2 to the length L1, i.e., L2 / L1, is less than 0.75. The toothbrush according to any one of (1) to (3) above.

[0015] (5) The length D1 is 2.5 mm or more and 3.8 mm or less, the length D2 that is the maximum thickness of the head portion is 2.0 mm or more and 3.5 mm or less, and in the front view, the head portion and the neck portion are arranged so as to overlap the extension line of the line segment A1 connecting the midpoints in the thickness direction of the gripping portion. The toothbrush according to any one of (1) to (4) above.

[0016] (6) The brush body is formed of only one type of hard resin. The toothbrush according to any one of (1) to (5) above. [[Effect of the Invention]]

[0017] According to the toothbrush of the present invention, the neck portion is likely to bend in the thickness direction. Further, since the position of the bending point of the neck portion can be shifted from the rear end side (gripping portion side) to the transition portion, torsional deflection of the head portion 10 in the torque direction can be suppressed. Therefore, the toothbrush according to the present invention can apply an appropriate force to the teeth during brushing, and usability is improved.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Modes for Carrying Out the Invention

[0019] Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. The embodiments shown here are examples for embodying the technical idea of the present invention and do not limit the present invention. Also, all other possible embodiments, examples, and operation techniques that can be conceived by those skilled in the art without departing from the gist of the present invention are included in the scope and gist of the present invention, and are included in the invention described in the claims and its equivalent scope.

[0020] Furthermore, the drawings attached to this specification may be schematically represented with appropriate changes in scale, aspect ratio, shape, etc. from the actual object for the convenience of illustration and easy understanding, but this is merely an example and does not limit the interpretation of the present invention.

[0021] The arrows X1 - X2 forming the X - axis in each figure indicate the longitudinal direction of the toothbrush 100. The side of arrow X1 indicates the tip side (the head part 10 side) of the toothbrush 100, and the side of arrow X2 indicates the rear end side (the gripping part 30 side) of the toothbrush 100. Also, the arrows Y1 - Y2 forming the Y - axis in each figure indicate the width direction of the toothbrush 100. Further, the arrows Z1 - Z2 forming the Z - axis in each figure indicate the thickness direction of the toothbrush 100.

[0022] In this specification, a plan view means looking at the toothbrush 100 from the side of the bristle - planting surface 11 of the head part 10, and a bottom view means looking at the toothbrush 100 from the side opposite to the bristle - planting surface 11 of the head part 10 (see FIGS. 5 and 6). A front view means looking from a direction orthogonal to the thickness direction of the head part 10 (see FIG. 3). The rear view shown in FIG. 4 appears symmetrically with the front view shown in FIG. 3.

[0023] Also, the "surface" of the gripping part 30 means the surface of the head part 10 facing the same direction as the bristle - planting surface 11 on which the bristle bundles 13 are planted, the "back surface" means the surface on the opposite side of the "surface", and the "side surface" means the surface other than the "surface", "back surface", and the surface on the proximal end side.

[0024] The toothbrush 100 according to this embodiment will be described with appropriate reference to FIGS. 1 to 14.

[0025] Figures 1 to 8 show the shape of the toothbrush 100 of the present embodiment. FIG. 1 is a perspective view of the toothbrush 100 viewed from the planar side (planar side perspective view), FIG. 2 is a perspective view of the toothbrush 100 viewed from the bottom side (bottom side perspective view), FIG. 3 is a front view of the toothbrush 100 (front view), FIG. 4 is a rear view of the toothbrush 100 (rear view), FIG. 5 is a plan view of the toothbrush 100 (plan view), FIG. 6 is a bottom view of the toothbrush 100 (bottom view), FIG. 7 is a left side view of the toothbrush 100 (left side view), and FIG. 8 is a right side view of the toothbrush 100 (right side view).

[0026] As shown in any of FIGS. 1 to 8, the toothbrush 100 includes a head portion 10 having a tufting surface 11 on which the tufts 13 of bristles are implanted and arranged on the tip side in the major axis direction, a neck portion 20 arranged on the rear end side of the head portion 10, a gripping portion 30 arranged on the rear end side of the neck portion 20, and a transition portion 40 arranged between the neck portion 20 and the gripping portion 30. The toothbrush 100 has a brush body 110 including the head portion 10, the neck portion 20, the gripping portion 30, and the transition portion 40.

[0027] The brush body 110 is integrally formed in an elongated shape as a whole and can be formed using a hard resin. Examples of the hard resin constituting the brush body 110 include polypropylene (PP), polyacetal (POM), polycyclohexylene dimethylene terephthalate (PCT), polyethylene terephthalate (PET), polycarbonate (PC), polymethyl methacrylate (PMMA), polystyrene (PS), acrylonitrile-butadiene-styrene resin (ABS), cellulose propionate (CP), polyarylate, etc. Also, biodegradable resins, plant-derived resins, paper-containing resins, plant-containing resins, etc. can be used for the above hard resins. Among these resins, polypropylene resin (PP) that is flexible and has low breakability is preferable as the resin from which the effects of the present invention can be obtained more remarkably.

[0028] Here, when a soft resin is used as the forming material of the brush body 110 or when the soft resin is coated, the shape of the gripping portion 30 when grasped changes, so it cannot always be held in the same way. Further, when the brush body 110 is formed by secondary molding, desired twist control and deflection control cannot be achieved. On the other hand, when polypropylene resin (PP) is used as the forming material of the brush body 110, appropriate deflection and twist suppression can be achieved. Further, the toothbrush 100 can be held at the same angle and with the same force regardless of where on the gripping portion 30 it is held and at what angle, so it has excellent operability. Therefore, it is more preferable that the toothbrush 100 uses polypropylene (PP) as the hard resin constituting the brush body 110.

[0029] Further, it is preferable that the entire brush body 110 is formed of the same hard resin. When the brush body 110 is formed of a common hard resin, it becomes possible to suitably transmit the force applied to the gripping portion 30 to the head portion 10.

[0030] In the present embodiment, the boundary P1 between the head portion 10 and the neck portion 20, the boundary P2 between the neck portion 20 and the transition portion 40, and the boundary P3 between the transition portion 40 and the gripping portion 30 are defined as follows.

[0031] The boundary P1 between the head portion 10 and the neck portion 20 is, as shown in FIGS. 5 and 9, the position of the end point where the width of the head portion 10 in the plan view shape is reduced, or as shown in FIG. 11, the position of the end point where the thickness of the head portion 10 in the front view shape is enlarged. However, when the positions of the above-described end points are shifted in the major axis direction, the boundary position is the position of the end point closer to the gripping portion 30.

[0032] The boundary P2 between the neck portion 20 and the transition portion 40 is, as shown in FIGS. 5 and 9, the position of the starting point where the width of the transition portion 40 in the plan view shape is enlarged, or as shown in FIG. 11, the position of the starting point where the thickness of the transition portion 40 in the front view shape is enlarged. However, when the positions of the above-described starting points are shifted in the major axis direction, the boundary position is the position of the starting point closer to the head portion 20.

[0033] As shown in FIGS. 5 and 9, the boundary P3 between the transition portion 40 and the gripping portion 30 is the position of the end point where the width of the transition portion 40 in the plan view shape expands in diameter, or as shown in FIG. 11, the position of the end point where the thickness of the transition portion 40 in the front view shape expands in diameter. However, when the positions of the above-described end points are shifted in the major axis direction, the boundary position is the position of the end point closer to the gripping portion 30 side.

[0034] <Head portion> The head portion 10 is disposed on the tip side of the toothbrush 100 and has a configuration integrally connected to the neck portion 20. The head portion 10 has a tufted surface 11 on one surface in the thickness direction. A plurality of tufting holes 12 are formed in the tufted surface 11, and tufts 13 of bristles for use are implanted in the tufting holes 12. The plurality of tufts 13 constitute the brush portion 14. The toothbrush 100 can clean the oral cavity with the brush portion 14 of the head portion 10.

[0035] Regarding the material of the bristles constituting the tuft 13, the number of bristles per tuft 13, the number of tufts 13 arranged, etc., can be arbitrarily selected. The shape of the bristles includes bristles (tapered bristles) whose diameter gradually decreases toward the bristle tip and the bristle tip is sharpened, and bristles (straight bristles) whose diameter is substantially the same from the tufted surface 11 toward the bristle tip. Examples of straight bristles include those with a bristle tip that is a plane substantially parallel to the tufted surface 11 and those with a bristle tip rounded into a hemispherical shape. The cross-sectional shape of the bristles is not particularly limited, and may be circular such as a perfect circle or an ellipse, a polygon, a star shape, a three-leaf clover shape, a four-leaf clover shape, etc. The cross-sectional shapes of all the bristles may be the same or different.

[0036] As shown in FIG. 9, the length D2 at which the head portion 10 has the minimum thickness can be defined as the thickness of the head portion 10 at the position where the thickness of the head portion 10 is minimum in the Z-axis direction. For the head portion 10, the lower limit of the length D2 at which the minimum thickness is obtained is preferably 2.0 mm or more. The upper limit of the length D2 is preferably 3.5 mm or less.

[0037] The length W2 that is the maximum width of the head portion 10 can be defined as the width of the head portion 10 at the position where the width of the head portion 10 is maximum in the Y-axis direction, as shown in FIG. 10. The lower limit of the length W2 is preferably 10.0 mm or more. The upper limit of the length W2 is preferably 15.0 mm or less.

[0038] The head portion 10 is preferably provided with a rib 15 on the bottom surface 16 on the rear end side, and can have a shape that is continuous such that the thickness transitions from the length D1 that is the minimum thickness of the head portion 10 to the length D2 that is the thickness of the neck portion 20.

[0039] As shown in FIG. 11, the head portion 10 and the neck portion 20 are preferably arranged so as to overlap with the extension line of the line segment A1 connecting the midpoints in the thickness direction of the gripping portion 30 in a front view (and a rear view). Thereby, in the toothbrush 100, since the "hand movement" and the "movement of the head portion 10 and the neck portion 20" are likely to be interlocked when rotated in the torque direction with respect to the major axis direction of the gripping portion 30, the toothbrush 100 can be applied to the tooth surface at an appropriate angle, and furthermore, the torsion of the head portion 10 in the torque direction can be suppressed.

[0040] <Neck portion> The neck portion 20 is arranged such that the tip is adjacent to the base end of the head portion 10 and the base end is adjacent to the tip of the transition portion 40. The neck portion 20 has a straight shape with a substantially rectangular cross-sectional shape that is wide and flat (horizontally flat). Note that "substantially rectangular" refers to a shape in which the corner R is 5.0 or less.

[0041] FIG. 12 is a cross-sectional view of the boundary P1 between the head portion 10 and the neck portion 20. The length D1 in the thickness direction of the neck portion 20 can be defined as the thickness of the neck portion 20 in the Z-axis direction, as shown in FIG. 12. The lower limit of the length D1 is preferably 2.5 mm or more. The upper limit of the length D1 is preferably 3.8 mm or less.

[0042] The length W1 in the width direction of the neck portion 20 can be defined as the width of the neck portion 20 in the Y-axis direction, as shown in FIG. 12. The lower limit of the length W1 is preferably 4.8 mm or more. The upper limit of the length W1 is preferably 6.0 mm or less.

[0043] As shown in Fig. 9, the length L1 of the neck portion 20 in the major axis direction can be defined as the total length of the neck portion 20 in the X-axis direction. The lower limit of the length L1 is preferably 30.0 mm or more. The upper limit of the L1 is preferably 35.0 mm or less.

[0044] As shown in Fig. 12, when the length in the thickness direction of the neck portion 20 is D1 and the length in the width direction is W1, both the length D1 and the length W1 remain constant values, and the neck portion 20 extends in the major axis direction while satisfying the relationship W1 > D1. Here, "constant" means that both the length D1 and the length W1 are ±0.5 mm or W1 / D1 is ±0.1.

[0045] In the toothbrush 100 of the present embodiment, the cross-sectional shape of the neck portion 20 has a substantially rectangular cross-sectional shape that is horizontally long and flat. Further, the length D1 and the length W1 are constant values, and while satisfying the relationship W1 > D1, it extends in the major axis direction from the proximal end of the head portion 10 toward the gripping portion 30. Thereby, the neck portion 20 becomes easily bendable in the thickness direction. In addition, since the position of the bending point of the neck portion 20 can be positioned at the transition portion 40 from the rear end side (gripping portion 30 side), torsional deflection of the head portion 10 in the torque direction can be suppressed. Therefore, the toothbrush 100 can apply an appropriate force to the teeth during brushing, and the usability is improved.

[0046] For the neck portion 20, W1 / D1, which is the ratio of the length W1 in the width direction to the length D1 in the thickness direction, is 1.25 or more.

[0047] In a toothbrush, when the ratio of the length in the width direction to the length in the thickness direction of the neck portion is less than 1.25, the bending of the neck portion becomes small, and the usability may decrease. On the other hand, in the toothbrush 100 of the present embodiment, by extending the neck portion 20 in a straight shape along the major axis direction with W1 / D1 ≧ 1.25, the neck portion 20 becomes easily bendable in the thickness direction, and the usability can be improved.

[0048] As shown in FIGS. 9(a) and 9(b), the neck portion 20 is connected with the same width to the first ridge line 33 forming the outer peripheral surface of the gripping portion 30, where the third ridge line 21 serves as the contour line in the plan view and the bottom view. The third ridge line 21 is connected with the same width to the first ridge line 33 that partitions the first outer peripheral surface 31 which is the surface of the gripping portion 30 and the first ridge line 33 that partitions the second outer peripheral surface 32 which is the back surface of the gripping portion 30. As shown in FIGS. 9(a) and 9(b), the first ridge line 33 and the third ridge line 21 are continuously connected via the second ridge line 41 formed on the front surface side and the back surface side of the transition portion 40. Here, "connected with the same width" does not limit to the form where the length in the width direction of the third ridge line 21 which is the contour line of the neck portion 20, the length in the width direction of the first ridge line 33 that partitions the first outer peripheral surface 31 of the gripping portion 30, and the length in the width direction of the first ridge line 33 that partitions the second outer peripheral surface 32 of the gripping portion 30 are the same, but also includes the state where they are connected with a deviation within 1 mm in the width direction.

[0049] Thereby, the torque direction twist of the head portion 10 of the toothbrush 100 is suppressed, and the deflection direction of the neck portion 20 is easily limited only to the thickness direction.

[0050] <Gripping portion> The gripping portion 30 is arranged with its tip adjacent to the base end of the transition portion 40. The gripping portion 30 is gripped by a user's finger or the like when cleaning (brushing) the oral cavity.

[0051] The gripping portion 30 has a straight shape with a substantially polygonal cross-sectional shape of hexagon or more. The gripping portion 30 extends with the same cross-sectional shape from the tip to the base end. Note that, from the viewpoint of ease of holding, R processing may be applied to some of the corner portions of the polygon constituting the cross-sectional shape of the gripping portion 30.

[0052] FIG. 13 is a cross-sectional view of the rear end side of the gripping portion 30, and FIG. 14 is a cross-sectional view of the boundary P3 between the gripping portion 30 and the transition portion 40. As shown in FIGS. 13 and 14, the gripping portion 30 of the present embodiment has a form in which the radius of curvature of the corner R on the back surface side changes slightly at the front end side and the rear end side. The length D3 in the thickness direction of the gripping portion 30 can be defined as the thickness of the gripping portion 30 in the Z-axis direction, as shown in FIGS. 13 and 14. The lower limit of the length D3 is preferably 7.0 mm or more. The upper limit of the length D3 is preferably 12.0 mm or less.

[0053] The length W3 in the width direction of the gripping portion 30 can be defined as the width of the gripping portion 30 in the Y-axis direction, as shown in FIGS. 13 and 14. The lower limit of the length W3 is preferably 7.0 mm or more. The upper limit of the length W3 is preferably 12.0 mm or less.

[0054] The gripping portion 30 has a plurality of outer peripheral surfaces that define a polygon in cross-sectional shape. Each outer peripheral surface is partitioned by a plurality of first ridges 33 arranged in the circumferential direction of the gripping portion 30. Among the plurality of outer peripheral surfaces that define a polygon in cross-sectional shape of the gripping portion 30, the first outer peripheral surface 31 located on the 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 bristle planting surface 11 of the head portion 10 and the bottom surface 16 of the head portion 10 opposite to the bristle planting surface 11.

[0055] The gripping portion 30 has a cross-sectional shape that is a polygon with six or more sides and extends straight with the same cross-sectional shape from the tip to the base end. Further, since the first outer peripheral surface 31 and the second outer peripheral surface 32 are parallel to the bristle planting surface 11 and the bottom surface 16 of the head portion 10, the way of holding the gripping portion 30 does not change anywhere in the length direction, and a force can be easily applied in the thickness direction of the bristle planting surface 11. Also, when the gripping portion 30 is rotated in the torque direction with respect to the major axis direction, the gripping portion 30 can be held in the same way, so the operability is good. Therefore, the toothbrush 100 enables appropriate neck deflection and uniform brushing.

[0056] The gripping portion 30 can be provided with an anti-slip portion 50 on at least a part of its outer peripheral surface. As shown in FIG. 1 and the like, the anti-slip portion 50 can be configured by arranging a plurality of regions subjected to dimpling processing in the major axis direction in parallel. The anti-slip portion 50 is preferably formed in a region on the neck portion side (the tip side region of the gripping portion 30) on the front or back surface of the gripping portion 30. Thereby, when the user grips the gripping portion 30 with a palm grip, the thumb, index finger, etc. abut against the anti-slip portion 50, so that the gripping portion 30 can be firmly gripped, and the force applied to the gripping portion 30 can be firmly transmitted to the teeth. Note that the shape, arrangement position, material, etc. of the anti-slip portion 50 are not particularly limited as long as the anti-slip function can be obtained by contact with the fingers when the user grips the gripping portion 30.

[0057] <Transition portion> The transition portion 40 is arranged such that its tip is adjacent to the base end of the neck portion 20 and its base end is adjacent to the tip of the gripping portion 30. The transition portion 40 connects the neck portion 20 and the gripping portion 30 in the toothbrush 100. In the major axis direction, the widths in the width direction and the lengths in the thickness direction of the transition portion 40 increase from the neck portion 20 toward the gripping portion 30.

[0058] As shown in FIG. 9, the length L2 of the transition portion 40 in the major axis direction can be defined as the total 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. The upper limit of the L2 is preferably 22.0 mm or less.

[0059] The ratio L2 / L1, which is the ratio of the length L2 of the transition portion 40 in the major axis direction to the length L1 of the neck portion 20 in the major axis direction, is less than 0.75. The lower limit of the L2 / L1 is preferably more than 0.45.

[0060] In a toothbrush, when the ratio of the length in the major axis direction of the neck portion to the length in the major axis direction of the transition portion is 0.75 or more, the length of the neck portion that bends appropriately becomes short, so the degree of bending of the neck portion becomes low, and the usability may deteriorate. Further, when the ratio of the length in the major axis direction of the neck portion to the length in the major axis direction of the transition portion is less than 0.45, there is a possibility that the strength of the neck portion cannot be ensured from the viewpoint of stress concentration. On the other hand, in the toothbrush 100 of the present embodiment, L2 / L1, which is the ratio of the length L2 in the major axis direction of the transition portion 40 to the length L1 in the major axis direction of the neck portion 20, is less than 0.75. Therefore, in the toothbrush 100, the neck portion 20 is easily bent in the thickness direction of the neck portion 20, and the usability is improved.

[0061] The transition portion 40 has a second ridge line 41 that extends continuously toward the tip side in continuity with the first ridge line 33 formed on the outer peripheral surface of the grip portion 30. As shown in FIG. 10, the second ridge line 41 is continuous with the first ridge line 33 located on the side surface side of the grip portion 30 that partitions the outer peripheral surface forming the side surface of the grip portion 30.

[0062] The toothbrush 100 of the present embodiment has a substantially rectangular cross-sectional shape in which the cross-sectional shape of the neck portion 20 is horizontally long and flat, and further has a constant value for the length D1 and the length W1, and satisfies the relationship of W1>D1 and extends in the major axis direction from the base end of the head portion 10 toward the grip portion 30. Further, the transition portion 40 has a second ridge line 41 that is continuous with the first ridge line 33 of the grip portion 30. As a result, the neck portion 20 is easily bent in the thickness direction. In addition, since the position of the bending point of the neck portion 20 can be moved from the rear end side (grip portion 30 side) to the transition portion 40, torsional deflection of the head portion 10 in the torque direction can be suppressed. Therefore, the toothbrush 100 can apply an appropriate force to the teeth during brushing, and the usability is improved.

[0063] The toothbrush 100 of the present embodiment is characterized by the shape of the brush body 110 in that the neck portion 20 is horizontally flat, has the same cross-sectional shape, extends straight in the major axis direction, and the length of the transition portion 40 is short. In a general toothbrush, the neck portion has a curved shape with an R and does not maintain a straight shape with the same cross-sectional shape. This is to realize an S-shaped configuration along the tooth row or to ensure strength. However, many toothbrushes with an S-shaped neck portion have a substantially circular cross-sectional shape, and sufficient deflection of the neck portion cannot be ensured, and the torsion of the head portion in the torque direction cannot be controlled, and torsion may occur. In contrast, the toothbrush 100 of the present embodiment adopts a straight shape that is horizontally flat and has the same cross-sectional shape, which is a shape that easily realizes deflection in the thickness direction. However, if the toothbrush 100 simply has a straight shape with a horizontally flat and identical cross-sectional shape for the neck portion 20, it is difficult to suppress the torsion of the head portion 10 in the torque direction. Therefore, the toothbrush 100 adopts a new shape of "positioning the bending point as close as possible to the rear end of the neck portion 20 by providing a long straight portion of the neck portion 20" and "arranging the transition portion 40 from the neck portion 20 to the gripping portion 30 at the bending point near the rear end of the neck portion 20 and providing a firm ridge line from the neck portion 20 to the gripping portion 30 (that is, the first ridge line 33 of the gripping portion 30 and the third ridge line 21 of the neck portion 20 are connected with the same width, providing a second ridge line 41 continuous with the first ridge line 33, etc.)" to suppress the torsion of the head portion 10 in the torque direction.

[0064] As described above, the toothbrush 100 according to the present embodiment includes a head portion 10 disposed on the tip side in the long axis direction and having a tufted surface 11, a neck portion 20 disposed on the rear end side of the head portion 10, and a grip portion 30 disposed on the rear end side of the neck portion 20, and has a brush body 110. The neck portion 20 has a straight shape with a substantially rectangular cross-sectional shape that is wide. When the length in the thickness direction of the neck portion 20 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 long axis direction. Between the neck portion 20 and the grip portion 30, there is a transition portion 40 in which the length in the width direction and the length in the thickness direction increase from the neck portion 20 toward the grip portion 30. The transition portion 40 has a second ridge line 41 that is continuous with a first ridge line 33 formed on the outer peripheral surface of the grip portion 30 and extends toward the tip side.

[0065] With such a configuration, in the toothbrush 100 of the present embodiment, the neck portion 20 is likely to bend in the thickness direction. Further, since the position of the bending point of the neck portion 20 can be positioned at the transition portion 40 from the rear end side (grip portion 30 side), torsional deflection of the head portion 10 in the torque direction can be suppressed. Therefore, the toothbrush 100 can apply an appropriate force to the teeth during brushing, and the usability is improved.

Explanation of Reference Numerals

[0066] 10 Head portion, 11 Tufted surface, 12 Tufting holes, 13 Tuft, 14 Brush portion, 15 Rib, 16 Bottom surface of the head portion, 20 Neck portion, 21 Third ridge line, 30 Grip portion, 31 First outer peripheral surface, 32 Second outer peripheral surface, 33 First ridge line, 40 Transition portion, 41 Second ridge line, 50 Anti-slip portion, 100 Toothbrush, 110 Brush body A line segment connecting the midpoints in the thickness direction of the gripping part, D1 The length in the thickness direction of the neck part, D2 The minimum thickness of the head part, D3 The maximum thickness of the gripping part, P1 The boundary between the head part and the neck part, P2 The boundary between the neck part and the transition part, P3 The boundary between the transition part and the gripping part, L1 The length in the major axis direction of the neck part, L2 The length in the major axis direction of the transition part, W1 The length in the width direction of the neck part, W2 The maximum width of the head part, W3 The maximum width of the gripping part.

Claims

1. It has a brush body including a head portion having a tufted surface disposed on the tip side in the major axis direction, a neck portion disposed on the rear end side of the head portion, and a gripping portion disposed on the rear end side of the neck portion. The neck portion has a straight shape with a substantially rectangular cross-sectional shape that is wide. When the length in the thickness direction of the neck portion 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 major axis direction. Between the neck portion and the gripping portion, there is a transition portion where the length in the width direction and the length in the thickness direction increase from the neck portion toward the gripping portion. The transition portion has a second ridge line that extends toward the tip side continuously with a first ridge line formed on the outer peripheral surface of the gripping portion. The toothbrush.

2. The toothbrush according to claim 1, wherein W1 / D1, which is the ratio of the length W1 to the length D1 of the neck portion, is 1.25 or more.

3. The gripping portion has a polygonal cross-sectional shape of a hexagon or more, and extends straight in the major axis direction with the same cross-sectional shape from the tip to the base end. Among the plurality of outer peripheral surfaces defining the polygon, a first outer peripheral surface located on the surface and a second outer peripheral surface located on the back surface opposite to the first outer peripheral surface are parallel to the tufted surface of the head portion and the bottom surface of the head portion opposite to the tufted surface. The toothbrush according to claim 1, wherein a third ridge line that is the contour line in the plan view and bottom view of the neck portion is connected with the same width as the first ridge line forming the outer peripheral surface of the gripping portion.

4. The toothbrush according to claim 1, wherein L2 / L1, which is the ratio of the length L2 in the major axis direction of the transition portion to the length L1 in the major axis direction of the neck portion, is less than 0.

75.

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

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

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