Toothbrush

Abstract

To achieve oral cavity operability and firm polishing feelings by transmitting the force applied to a grip part to a bristle-implanted part surely while suppressing bending of a neck part.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 vertically long flat roughly square cross-sectional shape, and extends along 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 D1>W1.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a toothbrush.

Background Art

[0002] Generally, a toothbrush is required to achieve both good oral operability and a firm brushing feel, and the design of the neck portion and the gripping portion is important in realizing these. In particular, in order to achieve a firm brushing feel, it is necessary to control the deflection from the neck portion to the gripping portion.

[0003] Currently, in order to ensure oral operability, there are many toothbrushes having a neck portion with a thin cross-sectional shape. In particular, from the viewpoint of ensuring the strength at the boundary between the neck portion and the gripping portion, the neck portion often gradually increases in width and thickness toward the gripping portion and is connected in a gentle R shape. However, with such a shape, when brushing, the force applied to the gripping portion is lost due to deflection from the neck portion to the entire gripping portion, and there is concern about a decrease in the firm brushing feel.

[0004] Also, Patent Document 1 discloses a toothbrush having an S-shaped neck portion in order to achieve oral operability.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The toothbrush of Patent Document 1 improves oral operability by making the shape of the neck portion S-shaped. However, on the other hand, it is difficult to directly transmit the force from the gripping portion to the tuft portion in the brushing direction (the direction in which the brushing pressure is applied), and there is concern about a decrease in the firm brushing feel.

[0007] At least one embodiment of the present invention has been made in view of the above circumstances. Specifically, while suppressing the bending of the neck portion, the force applied to the gripping portion is firmly transmitted to the tuft portion, and an object of the present invention is to provide a toothbrush capable of achieving both good oral cavity operability and a firm feeling of brushing.

Means for Solving the Problems

[0008] The above object of the present invention is achieved by any one of the following (1) to (7).

[0009] (1) A toothbrush having a brush body including a head portion disposed on the tip side in the major axis direction and having a tuft surface, a gripping portion disposed on the rear end side of the head portion, and a neck portion connecting the head portion and the gripping portion, wherein the neck portion has a straight shape with a vertically long and flat substantially rectangular cross-sectional shape, 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 D1>W1 and extend along the major axis direction.

[0010] (2) The toothbrush according to (1) above, wherein W1 / D1, which is the ratio of the length W1 to the length D1 of the neck portion, is less than 0.8.

[0011] (3) Between the neck portion and the gripping portion, there is a transition portion whose length in the width direction and length in the thickness direction increase from the neck portion toward the gripping portion. When the length in the major axis direction of the neck portion is L1 and the length in the major axis direction of the transition portion is L2, L2 / L1, which is the ratio of the length L2 to the length L1, is less than 0.6. The toothbrush according to (1) or (2) above.

[0012] (4) The length D2 at which the head part has the minimum thickness is 2.0 mm or more and 3.5 mm or less, the ratio D2 / D1 which is the ratio of the length D2 to the length D1 is less than 0.8, the length W2 at which the head part has the maximum width is 10.0 mm or more and 15.0 mm or less, and the ratio W1 / W2 which is the ratio of the length W1 to the length W2 is less than 0.4, the toothbrush according to any one of (1) to (3) above.

[0013] (5) The gripping part has a straight shape with a substantially rectangular cross-sectional shape. When the length at which the gripping part has the maximum thickness is D3 and the length at which the gripping part has the maximum width is W3, the length D3 and the length W3 are constant values, and the surface of the gripping part extends in the longitudinal direction with a constant shape parallel to the bristle-planting surface. The ratio D1 / D3 which is the ratio of the length D1 to the length D3 exceeds 0.3, the ratio W1 / W3 which is the ratio of the length W1 to the length W3 is less than 0.5, and the transition part connects the ridge lines formed in the region of the neck part and the region of the gripping part and the width and thickness increase from the tip toward the base end. The toothbrush according to any one of (1) to (4) above.

[0014] (6) The difference between the length W2 at which the head part has the maximum width and the length W3 at which the gripping part has the maximum width is within 2.0 mm. The toothbrush according to any one of (1) to (5) above.

[0015] (7) The brush body is formed of a hard resin. The toothbrush according to any one of (1) to (6) above.

Advantages of the Invention

[0016] According to the toothbrush of the present invention, the neck portion has a straight shape with a substantially square cross-sectional shape, the length D1 in the thickness direction and the length W1 in the width direction of the neck portion are constant values, and the length W1 and the length D1 satisfy the relationship D1>W1 and extend along the major axis direction. Therefore, the neck portion is bent on the rear end side (grip portion side), and it is possible to transmit the force applied to the grip portion to the head portion while minimizing the deflection of the neck portion in the width direction and the thickness direction. In addition, since the neck portion has a straight shape, the force applied to the grip portion is firmly transmitted in the direction perpendicular to the teeth. Therefore, the toothbrush of the present invention can firmly transmit the force applied to the grip portion to the tuft portion while minimizing the deflection of the neck portion, and can achieve both good oral operability and a firm brushing feeling.

Brief Description of the Drawings

[0017]

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

Figure 15

Embodiments for Carrying Out the Invention

[0018] 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, 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 all included in the scope and gist of the present invention, and are included in the invention described in the claims and its equivalent scope.

[0019] Furthermore, the drawings attached to this specification may be schematically represented with changes from the actual object in terms of scale, aspect ratio of length and width, shape, etc. for the convenience of illustration and easy understanding, but this is merely an example and does not limit the interpretation of the present invention.

[0020] 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 (head portion 10 side) of the toothbrush 100, and the side of arrow X2 indicates the rear end side (grip portion 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.

[0021] In this specification, a plan view means looking at the toothbrush 100 from the side of the tufted surface 11 of the head portion 10, and a bottom view means looking at the toothbrush 100 from the side opposite to the tufted surface 11 of the head portion 10 (see FIGS. 5 and 6). A front view means looking from a direction orthogonal to the thickness direction of the head portion 10 (see FIG. 3). The rear view shown in FIG. 4 appears symmetrically to the front view shown in FIG. 3.

[0022] Further, the "surface" of the gripping portion 30 refers to the surface of the head portion 10 that faces in the same direction as the hair implanting surface 11 where the hair bundles 13 of the bristles 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 proximal end side.

[0023] The toothbrush 100 according to the present embodiment will be described with appropriate reference to FIGS. 1 to 15. In each figure, for ease of understanding the shape, a line indicating the shape of a part of the corner R is described as necessary.

[0024] The shapes of the toothbrush 100 of the present embodiment are shown in FIGS. 1 to 8. FIG. 1 is a perspective view of the toothbrush 100 viewed from the plane side (plane 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).

[0025] As shown in any of FIGS. 1 to 8, the toothbrush 100 has a head portion 10 having a hair implanting surface 11 on which the hair bundles 13 of the bristles are implanted, which is arranged on the distal end 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.

[0026] The brush body 110 is integrally formed in an overall long shape and can be formed using a hard resin. As the hard resin constituting the brush body 110, for example, polypropylene (PP), polyacetal (POM), polycyclohexylene dimethylene terephthalate (PCT), polyethylene terephthalate (PET), polycarbonate (PC), acrylonitrile-butadiene-styrene resin (ABS), polymethyl methacrylate (PMMA), polystyrene (PS), acrylonitrile-butadiene-styrene resin (ABS), cellulose propionate (CP), polyarylate, etc. can be used. Further, as the above hard resin, biodegradable resin, plant-derived resin, paper-blended resin, plant-blended resin, etc. can also be used. Among these resins, polypropylene resin (PP) is preferable as the resin from which the effects of the present invention can be obtained more remarkably.

[0027] Also, 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 grip portion 30 to the head portion 10. When a part of the grip portion 30 contains a soft resin, the force when grasped is dispersed within the soft resin, and it is difficult to firmly transmit the grasped force to the tip of the grip portion 30.

[0028] 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 grip portion 30 are defined as follows.

[0029] 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 decreases, 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 increases in diameter. However, when the positions of the above-described end points are shifted in the major axis direction, the position of the end point closer to the grip portion 30 is taken as the boundary position for the boundary P1.

[0030] As shown in FIGS. 5 and 9, the boundary P2 between the neck portion 20 and the transition portion 40 is the position where the width of the transition portion 40 in the plan view shape starts to increase in diameter, or as shown in FIG. 11, it is the position where the thickness of the transition portion 40 in the front view shape starts to increase in diameter. 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 10 side.

[0031] As shown in FIGS. 5 and 9, the boundary P3 between the transition portion 40 and the gripping portion 30 is the position where the width of the transition portion 40 in the plan view shape ends increasing in diameter, or as shown in FIG. 11, it is the position where the thickness of the transition portion 40 in the front view shape ends increasing 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.

[0032] <Head portion> As shown in FIGS. 1, 3, 5, etc., 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.

[0033] Regarding the material of the bristles constituting the tuft 13, the number of bristles per tuft 13, the number of arrangements of the tufts 13, 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 whose bristle tips are in a plane substantially parallel to the tufted surface 11 and those whose bristle tips are 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.

[0034] The length D2 at which the thickness of the head portion 10 is minimized can be defined as the thickness of the head portion 10 at the position where the thickness of the head portion 10 is minimized in the Z-axis direction, as shown in FIG. 10. The lower limit of the length D2 is preferably 2.0 mm or more. The upper limit of the length D2 is preferably 3.5 mm or less.

[0035] The length W2 at which the width of the head portion 10 is maximized can be defined as the width of the head portion 10 at the position where the width of the head portion 10 is maximized in the Y-axis direction, as shown in FIG. 9. The lower limit of the length W2 is preferably 10.0 mm or more, more preferably 11.0 mm or more. The upper limit of the length W2 is preferably 15.0 mm or less, more preferably 12.5 mm or less.

[0036] 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 continuous shape such that the thickness transitions from the length D1 which is the minimum thickness of the head portion 10 to the length D2 which is the thickness of the neck portion 20.

[0037] As shown in FIG. 11, the head portion 10 is 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 the front view (and rear view). Further, the head portion 10 is more preferably arranged at a position where it completely overlaps with the extension line of the line segment A1 connecting the midpoints in the thickness direction of the gripping portion 30 (the position passing through the inside of the head portion 10 in the side view). Thereby, the toothbrush 100 can firmly transmit the force applied to the gripping portion 30 in the direction perpendicular to the teeth.

[0038] <Neck portion> As shown in FIGS. 1, 3, 5, etc., the neck portion 20 is arranged such that its tip is adjacent to the base end of the head portion 10 and its base end is adjacent to the tip of the transition portion 40. The neck portion 20 has a straight shape with a vertically long and flat (vertically flat) substantially rectangular cross-sectional shape. Note that "substantially rectangular" refers to a shape with a corner R of 5.0 or less.

[0039] FIG. 12 is a cross-sectional view of the boundary P1 between the head portion 10 and the neck portion 20. As shown in FIG. 12, 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. The lower limit of the length D1 is preferably 5.0 mm or more. The upper limit of the length D1 is preferably 6.0 mm or less.

[0040] The length W1 in the width direction of the neck portion 20 can be defined as the thickness of the neck portion 20 in the Y-axis direction, as shown in FIG. 12. The lower limit of the length W1 is preferably 3.0 mm or more. The upper limit of the length W1 is preferably 4.0 mm or less.

[0041] The length L1 in the major axis direction of the neck portion 20 can be defined as the total length of the neck portion 20 in the X-axis direction, as shown in FIG. 9. The lower limit of the length L1 is preferably 30 mm or more. The upper limit of the L1 is preferably 40 mm or less.

[0042] As shown in FIG. 12, when the neck portion 20 has a length D1 in the thickness direction and a length W1 in the width direction, both the length D1 and the length W1 remain constant values, and satisfy the relationship D1>W1 and extend in the major axis direction. Here, "constant" means that both the length D1 and the length W1 are ±0.5 mm or W1 / D1 is ±0.1.

[0043] In a general toothbrush, if the lengths in the width direction and thickness direction of the neck portion are set such that D1 > W1, there is a concern about deflection in the width direction of the neck portion. In contrast, in the toothbrush 100 of the present embodiment, the cross-sectional shape of the neck portion 20 has a vertically long and flat substantially rectangular cross-sectional shape, and the lengths D1 and W1 are constant values, and satisfy the relationship D1 > W1, and extend in the major axis direction from the proximal end of the head portion 10 toward the gripping portion 30. As a result, the neck portion 20 is bent on the rear end side (the gripping portion 30 side) and does not easily deflect. That is, when the bending point is at the rear end portion of the neck portion 20, the distance from the head portion 10 (the acting point) becomes long, and since the bending point is located at the transition portion 40 with a large amount of resin, it becomes difficult to deflect. As a result, the toothbrush 100 can transmit the force applied to the gripping portion 30 to the head portion 10 while suppressing the deflection in the thickness direction and width direction of the neck portion 20 to a minimum while ensuring the operability in the oral cavity, and thus a firm brushing feeling can be realized.

[0044] For the neck portion 20, W1 / D1, which is the ratio of the length D1 in the thickness direction to the length W1 in the width direction, is less than 0.8. The lower limit of the above W1 / D1 is preferably 0.5 or more. The upper limit of the above W1 / D1 is preferably 0.75 or less.

[0045] In a general toothbrush, since there is a concern about a decrease in the operability in the oral cavity due to an increase in the deflection in the width direction of the neck portion, the value of the above ratio is not set. In contrast, 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 < 0.8, the deflection in the thickness direction and width direction of the neck portion 20 can be suppressed to a minimum. Therefore, the toothbrush 100 can more effectively transmit the force applied to the gripping portion 30 to the head portion 10.

[0046] When the length D2, which is the minimum thickness of the head portion 10, is 2.0 mm or more and 3.5 mm or less, D2 / D1, which is the ratio of the length D2, which is the minimum thickness of the head portion 10, to the length D1 in the thickness direction of the neck portion 20, is less than 0.8. The lower limit of the above D2 / D1 is preferably 0.3 or more. The upper limit of the above D2 / D1 is preferably 0.7 or less.

[0047] When the length W2 of the maximum width of the head portion 10 is 10.0 mm or more and 15.0 mm or less, W1 / W2, which is the ratio of the length W1 in the width direction of the neck portion 20 to the length W2 of the maximum width of the head portion 10, is less than 0.4. The upper limit of the above W1 / W2 is preferably 0.35 or less.

[0048] In a general toothbrush, when the thickness of the head portion is greater than 3.5 mm, and the shape is such that D2 / D1 is 0.8 or more (D2 / D1≥0.8) and W1 / W2 is 0.4 or more (W1 / W2≥0.4), since the thickness does not change extremely between the head portion and the neck portion, there is concern about the overall deflection in the head portion and the neck portion. Also, in the above shape, the operability in the oral cavity for the back teeth may decrease. In contrast, the toothbrush 100 of the present embodiment has a shape in which the length D2 that is the minimum thickness of the head portion 10 is 2.0 mm or more and 3.5 mm or less, and D2 / D1 is less than 0.8 (D2 / D1<0.8), the length W2 that is the maximum width of the head portion 10 is 10.0 mm or more and 15.0 mm or less, and W1 / W2 is less than 0.4 (W1 / W2<0.4). Thereby, since the thickness (in the thickness direction and the width direction) of the head portion 10 and the neck portion 20 changes greatly, the deflection in the head portion 10 and the neck portion 20 can be suppressed, and a firm brushing feeling can be realized. In addition, the operability in the oral cavity is also improved.

[0049] The lower limit of the difference between the length D1 in the thickness direction of the neck portion 20 and the minimum thickness D2 of the head portion 10 is preferably 1.5 mm or more. Also, the upper limit of the difference between the length D1 and the D2 is preferably 4.0 mm or less.

[0050] The lower limit of the difference between the length W2 that is the maximum width of the head portion 10 and the length W1 in the width direction of the neck portion 20 is preferably 8.0 mm or more. Also, the upper limit of the difference between the length W2 and the length W1 is preferably 9.5 mm or less.

[0051] The value obtained by multiplying the ratio of the length D1 in the thickness direction of the neck portion 20 to the length W1 in the width direction of the neck portion 20 by the length L1 in the major axis direction of the neck portion 20 ((D1 / W1)×L1) is preferably greater than 30. The lower limit of the above (D1 / W1)×L1>30 is preferably 40 or more.

[0052] The larger the numerical value obtained by the above formula ((D1 / W1)×L1), the more vertically long and flat the neck portion 20 is, and the longer the straight region is. Therefore, the toothbrush 100 can firmly transmit the force applied to the gripping portion 30 to the head portion 10.

[0053] <Gripping portion> As shown in FIGS. 1, 3, 5, etc., 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.

[0054] The gripping portion 30 has a straight shape with a substantially square cross-sectional shape. Note that "substantially square" refers to a shape with a corner R of 5.0 or less.

[0055] FIG. 13 is a cross-sectional view of the boundary P3 between the transition portion 40 and the gripping portion 30. FIG. 14 is a cross-sectional view of a portion of the gripping portion 30 having one back R portion 31. FIG. 15 is a cross-sectional view of a portion of the gripping portion 30 having the other back R portion 31. Note that in this embodiment, the form is such that the radius of curvature of the corner R of the back R portion 31 of the gripping portion 30 changes slightly in part. 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, 14, and 15. The lower limit of the above length D3 is preferably 10.0 mm or more. The upper limit of the above length D3 is preferably 15.0 mm or less.

[0056] 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, 14, and 15. The lower limit of the above length W3 is preferably 10.0 mm or more. The upper limit of the above length W3 is preferably 15.0 mm or less.

[0057] As shown in FIG. 15, when the length in the thickness direction of the gripping portion 30 is D3 and the length in the width direction is W3, both the length D3 and the length W3 are constant values, and the surface of the gripping portion 30 extends in the major axis direction in a constant shape parallel to the flocked surface 11. Note that "constant" means that both the length D3 and the length W3 are ±0.5 mm.

[0058] Since the gripping portion 30 has a straight shape in which both the length D3 and the length W3 are constant values, and the surface of the gripping portion 30 extends in the major axis direction in a constant shape parallel to the flocked surface 11, the force applied to the gripping portion 30 can be firmly transmitted to the teeth in the vertical direction. In the gripping portion 30 of the present embodiment, although the radius of curvature of the back R portion 31 partially changes, the difference in the radius of curvature is minute, and the above-described effect can be obtained over the entire gripping portion 30.

[0059] D1 / D3, which is the ratio of the length D1 in the thickness direction of the neck portion 20 to the length D3 in the thickness direction of the gripping portion 30, preferably exceeds 0.3. The lower limit of D1 / D3 is preferably 0.4 or more. The upper limit of D1 / D3 is preferably 0.5 or less.

[0060] W1 / W3, which is the ratio of the length W1 in the width direction of the neck portion 20 to the length W3 in the width direction of the gripping portion 30, is less than 0.5. The upper limit of W1 / W3 is preferably 0.4 or less.

[0061] In a general toothbrush, when the shape is such that D1 / D3 is 0.3 or less (D1 / D3≤0.3) and W1 / W3 is 0.5 or more (W1 / W3≥0.5), the neck portion is likely to bend in the thickness direction, so there is concern about a decrease in intraoral operability. On the other hand, since the toothbrush 100 of the present embodiment has a shape in which D1 / D3 exceeds 0.3 (D1 / D3>0.3) and W1 / W3 is less than 0.5 (W1 / W3<0.5), while ensuring intraoral operability, the bending point in the neck portion 20 is on the rear end side (the gripping portion 30 side). Therefore, the toothbrush 100 can firmly transmit the force of the gripping portion 30 to the neck portion 20 while suppressing the bending of the neck portion 20 in the thickness direction.

[0062] The difference between the length W2 in the width direction of the head portion 10 and the length W3 in the width direction of the gripping portion 30 is within 2.0 mm.

[0063] In a general toothbrush, when the difference between the length in the width direction of the head portion and the length in the width direction of the gripping portion is 2 mm or more, when a force is firmly applied to the gripping portion, it cannot be firmly polished on the surface. In contrast, in the toothbrush 100 of the present embodiment, since the difference between the length W2 in the width direction of the head portion 10 and the length W3 in the width direction of the gripping portion 30 is within 2.0 mm, it can be firmly polished on the surface according to the magnitude of the force applied to the gripping portion 30 during brushing.

[0064] The lower limit of the difference between the length D3 in the thickness direction of the gripping portion 30 and the length D1 in the thickness direction of the neck portion 20 is preferably 4.0 mm or more. Also, the upper limit of the difference between the length D3 and the length D1 is preferably 10.0 mm or less.

[0065] The lower limit of the difference between the length W3 in the width direction of the gripping portion 30 and the length W1 in the width direction of the neck portion 20 is preferably 6.0 mm or more. Also, the upper limit of the difference between the length W3 and the length W1 is preferably 12.0 mm or less.

[0066] D2 / D3, which is the ratio of the length D2 in the thickness direction of the head portion 10 to the length D3 in the thickness direction of the gripping portion 30, is less than 0.4. The upper limit of D2 / D3 is preferably 0.35 or less.

[0067] The lower limit of the difference between the length D3 in the thickness direction of the gripping portion 30 and the length D2 in the thickness direction of the head portion 10 is preferably 6.5 mm or more. Also, the upper limit of the difference between the length D3 and the length D2 is preferably 13.0 mm or less.

[0068] As shown in FIGS. 13, 14, and 15, in the cross-sectional shape of the gripping portion 30, it is preferable that the back R portion 31, which is the corner R on the back side of the gripping portion 30, is larger than the front R portion 32, which is the corner R on the front side (back R portion > front R portion). That is, the radius of curvature R of the back R portion 31 is larger than the radius of curvature R of the front R portion 32. Thereby, when the user grips the gripping portion 30 in a pen grip, the toothbrush 100 can be gripped without pain, so that the force applied to the gripping portion 30 can be firmly transmitted in the direction perpendicular to the teeth.

[0069] 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 longitudinal 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 surface of the gripping portion 30. Thereby, when the user grips the gripping portion 30 in a palm grip, the anti-slip portion 50 and the fingertip of the thumb come into contact, 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.

[0070] <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 longitudinal direction, the width or thickness of the transition portion 40 increases from the neck portion 20 toward the gripping portion 30.

[0071] As shown in FIG. 9, the longitudinal length L2 of the transition portion 40 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 5.0 mm or more. The upper limit of L2 is preferably 15.0 mm or less.

[0072] The ratio L2 / L1, which is the ratio of the length L2 in the major axis direction of the transition part 40 to the length L1 in the major axis direction of the neck part 20, is less than 0.6. The lower limit of the above L2 / L1 is preferably 0.1 or more. The upper limit of the above L2 / L1 is preferably 0.5 or less.

[0073] In a general toothbrush, when the length in the major axis direction of the neck part is shorter than the length in the major axis direction of the transition part, the bending point in the neck part moves to the tip side (head part side), so the neck part is easily bent. On the other hand, in the toothbrush 100 of the present embodiment, the ratio L2 / L1, which is the ratio of the length L2 in the major axis direction of the transition part 40 to the length L1 in the major axis direction of the neck part 20, is less than 0.6 (L2 / L1 < 0.6). Therefore, in the toothbrush 100, the bending point in the neck part 20 can move to the rear end side (grip part 30 side). Therefore, the toothbrush 100 can firmly transmit the force applied to the grip part 30 to the head part 10 while minimizing the bending of the neck part 20 in the width direction and the thickness direction.

[0074] The transition part 40 increases in width and thickness from the tip toward the base while connecting the respective ridge lines formed in the region of the neck part 20 and the region of the grip part 30. In other words, the transition part 40 has a third ridge line 43 that connects the first ridge line 21 formed in the neck part 20 and the second ridge line 33 formed in the grip part 30. The first ridge line 21 is the contour line of the neck part 20 in plan view and front view. The second ridge line 33 is the contour line of the grip part 30 in plan view and front view.

[0075] By increasing the width or thickness from the tip toward the base while connecting the respective ridge lines (the first ridge line 21 and the second ridge line 33) formed in the region of the neck part 20 and the region of the grip part 30, the transition part 40 can control bending only in either the thickness direction or the width direction of the neck part 20 and suppress torsion in the rotational direction.

[0076] As shown in FIG. 10, in the front view, the radius of curvature of the first continuous surface 41 located on the back surface side (bottom surface side) of the outer peripheral surface of the transition portion 40 is larger than the radius of curvature of the second continuous surface 42 located on the front surface side (plane side) of the outer peripheral surface of the transition portion 40. That is, the way of bending (degree of bending) of the second continuous surface 42 is steeper than the way of bending (degree of bending) of the first continuous surface 41. Thereby, even when the length L2 in the major axis direction of the toothbrush 100 is short, the toothbrush 100 can disperse stress concentration on the surface.

[0077] As described above, the toothbrush 100 according to the present embodiment includes a head portion 10 disposed on the tip side in the major 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 longitudinally long and flat substantially rectangular cross-sectional shape. 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 D1>W1 and extend along the major axis direction.

[0078] With such a configuration, in the toothbrush 100 of the present embodiment, the neck portion 20 is bent on the rear end side (grip portion 30 side) and does not easily bend. Therefore, while ensuring oral operability, the force applied to the grip portion 30 is transmitted to the head portion 10 while suppressing the bending of the neck portion 20 in the thickness direction and the width direction to a minimum, and a firm brushing feeling can be realized.

Explanation of Reference Numerals

[0079] 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 First ridge line, 30 Grip portion, 31 Inner R portion, 32 Table-side R part, 33 Second ridge line, 40 Transition part, 41 First continuous surface, 42 Second continuous surface, 43 Third ridge line, 50 Anti-slip part, 100 Toothbrush, 110 Brush body A1 Line segment connecting the midpoints in the thickness direction of the gripping part, D1 Length in the thickness direction of the neck part, D2 Minimum thickness of the head part, D3 Maximum thickness of the gripping part, P1 Boundary between the head part and the neck part, P2 Boundary between the neck part and the transition part, P3 Boundary between the transition part and the gripping part, L1 Length in the major axis direction of the neck part, L2 Length in the major axis direction of the transition part, W1 Length in the width direction of the neck part, W2 Maximum width of the head part, W3 Maximum width of the gripping part.

Claims

1. A toothbrush having a brush body including a head portion disposed on the tip side in the major axis direction and having a tufted surface, 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, wherein the neck portion has a straight shape with a longitudinally long and flat substantially rectangular cross-sectional shape, 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 D1 > W1 and extend along the major axis direction.

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 less than 0.

8.

3. 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, when the length in the major axis direction of the neck portion is L1 and the length in the major axis direction of the transition portion is L2, L2 / L1, which is the ratio of the length L2 to the length L1, is less than 0.

6. The toothbrush according to claim 1 or 2.

4. The length D2, which is the minimum thickness of the head portion, is 2.0 mm or more and 3.5 mm or less, D2 / D1, which is the ratio of the length D2 to the length D1, is less than 0.8, the length W2, which is the maximum width of the head portion, is 10.0 mm or more and 15.0 mm or less, W1 / W2, which is the ratio of the length W1 to the length W2, is less than 0.

4. The toothbrush according to claim 1.

5. The gripping portion has a straight shape with a substantially rectangular cross-sectional shape. When the length that is the maximum thickness of the gripping portion is D3 and the length that is the maximum width of the gripping portion is W3, the length D3 and the length W3 are constant values, and the surface of the gripping portion extends in the major axis direction in a constant shape parallel to the tufted surface, D1 / D3, which is the ratio of the length D1 to the length D3, exceeds 0.3, W1 / W3, which is the ratio of the length W1 to the length W3, is less than 0.5, the transition portion connects the ridge lines formed in the region of the neck portion and the region of the gripping portion, and the width and thickness increase from the tip toward the base end. The toothbrush according to claim 1.

6. The difference between the length W2, which is the maximum width of the head portion, and the length W3, which is the maximum width of the gripping portion, is within 2.0 mm. The toothbrush according to claim 1.

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

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