Toothbrush

Abstract

To provide a toothbrush that is easy to grip without slipping during brushing, facilitates brushing with force as intended by a user even when force is applied to a head portion, and has the excellent tooth brushing operability.SOLUTION: There is provided a toothbrush comprising: a head portion having a substantially flat bristle implantation surface on which bristle bundles are implanted; a neck portion connected to the base end of the head portion; and a handle portion connected to the base end of the neck portion. The thickness in the front-rear direction along the protruding direction of the bristle bundles of the head portion is 2-4 mm, and the thickness in the front-rear direction of the neck portion is 4.0-5.3 mm. When defining center axes A1, A2, A3 of the head portion, neck portion, and handle portion as straight lines passing through the center in the front-rear thickness direction at the longitudinal center positions and parallel to the bristle implantation surface in a side view, the center axis A2 is shifted toward the rear side of the toothbrush relative to both center axes A1, A3. The handle portion has an outer shape that projects to the front and rear sides in the thickness direction in the finger rest region on the tip side and has an outer shape that is inwardly-concave toward the rear side of the toothbrush in a side view at positions excluding the finger rest region.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a toothbrush having a head portion in which tufts of hair are implanted and a handle body connected to the head portion.

Background Art

[0002] As a toothbrush with a head portion having a thickness of 2 to 4 mm and being thin, it is formed so as to be located before and after in the thickness direction with respect to the axis of the handle portion, and to be inclined such that the tip is located before and after in the thickness direction rather than the base end of the hair-implanted surface. The neck portion is set to have a thickness and width smaller than those of the handle portion, and is curved such that the front end is located before and after in the thickness direction with respect to the axis. A toothbrush having a substantially S-shaped overall shape (hereinafter, S-shaped toothbrush) is known (Patent Document 1). However, in the S-shaped toothbrush, since the axis of the handle portion has a curved shape with respect to the hair-implanted surface of the head portion, it is difficult to make the hair-implanted surface of the head portion parallel to the tooth surface in the mouth, and there is a problem that brushing is difficult.

[0003] Therefore, as a toothbrush with a thin head, a toothbrush (hereinafter, linear toothbrush) in which the axial directions of the neck portion and the handle portion are linear with respect to the axial direction of the head portion is known (Patent Document 2). The linear toothbrush described in Patent Document 2 is adjusted so as not to be excessively bent in the thickness direction by the finger rest portion 50 against which the thumb abuts having a convex apex 51 and a flat shape, and it is said that the propagation of deformation such as bending from the neck portion 4 to the gripping portion 5 can be suppressed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The above-mentioned straight toothbrush can apply the brush of the head portion to the tooth surface at a substantially right angle in the mouth as compared with the S-shaped toothbrush. However, for example, when the neck portion is deformed during brushing with a toothbrush as described in Citation Document 2, there is a problem that it is likely to have a sense of discomfort that was not a concern with the S-shaped toothbrush. On the other hand, if the neck portion is not bent, it becomes difficult to apply it at a substantially right angle to the tooth surface, and there is a problem that the operability in the mouth deteriorates. In addition, a toothbrush having a handle portion in a straight line shape as described in Citation Document 2 also has a problem that the portion held during brushing slips or becomes difficult to hold.

[0006] Therefore, in view of the above situation, the problem to be solved by the present invention is to provide a toothbrush with excellent toothbrushing operability that is easy to hold without slipping during brushing, and is easy to brush with the force as expected by the user even when a force is applied to the head portion.

Means for Solving the Problem

[0007] In view of such a situation, the inventors of the present invention conducted intensive studies. As a result, by appropriately suppressing the deformation of the neck portion and devising the positions of the central axes of the head portion, the neck portion, and the handle portion, the shape of the finger contact portion, and the shape of the handle portion in a side view, it is easy to hold without slipping during brushing by either the pen grip or the palm grip method, and it becomes easy to brush with the force as expected by the user, and the toothbrushing operability is improved. Thus, the present invention was completed.

[0008] That is, the present invention includes the following inventions. (1) A toothbrush comprising a head portion having a substantially flat tuft planting surface on which tufts are planted, a neck portion connected to the proximal end side of the head portion, and a handle portion connected to the proximal end side of the neck portion, the front-back thickness along the tuft protruding direction of the head portion is 2 to 4 mm, the front-back thickness of the neck portion is 4.0 to 5.3 mm, When the central axes of the head portion, the neck portion, and the handle portion are defined as straight lines passing through the centers in the front-rear thickness direction at the longitudinal center positions of the respective portions and parallel to the tufted surface in a side view, the central axis of the neck portion is shifted toward the rear surface side of the toothbrush with respect to both the central axis of the head portion and the central axis of the handle portion, the handle portion has an outer shape that protrudes in the front-rear thickness direction in a side view in the finger contact area on the tip side, and has an inner convex outer shape on the rear surface side of the toothbrush in a side view at positions other than the finger contact area, Toothbrush. (2) The toothbrush according to (1) above, wherein the handle portion has a linear outer shape having a predetermined length substantially parallel to the central axis of the handle portion on the front surface side of the toothbrush in a side view at positions other than the finger contact area on the tip side. (3) The toothbrush according to (1) or (2) above, wherein the central axis of the head portion and the central axis of the handle portion substantially coincide. (4) The toothbrush according to any one of (1) to (3) above, wherein the neck portion has a linear outer shape that overlaps the tufted surface on the front surface side of the toothbrush in a side view. (5) The toothbrush according to any one of (1) to (4) above, wherein the apex of the front convex portion protruding on the front surface side in a side view in the finger contact area of the handle portion is set closer to the head portion than the apex of the rear convex portion protruding on the rear surface side.

[0009] In the present invention, "front" refers to the direction in which the bristles protrude, and the opposite side is referred to as "rear".

Advantages of the Invention

[0010] According to the toothbrush of the present invention configured as described above, it is easy to grip firmly without slipping in either the pengrip or palm grip method during brushing, and even when force is applied to the head portion, it is easy for the user to brush with the expected force, enabling efficient toothbrushing.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0012] Next, embodiments of the present invention will be described in detail based on the accompanying drawings.

[0013] As shown in FIG. 1, the toothbrush 1 according to the present invention includes a head portion 2 having a substantially flat bristle-planting surface 5 on which bristle bundles 20 are planted, a neck portion 3 connected to the proximal end side of the head portion 2, and a handle portion 4 connected to the proximal end side of the neck portion 3.

[0014] The toothbrush 1 according to the present invention is a toothbrush with a thin head, and the front-to-back thickness along the bristle bundle protruding direction of the head portion 2 is 2 to 4 mm. By having the thin head portion 2 as described above, there is an advantage that it is easy to insert the head portion 2 into narrow areas in the oral cavity, for example, up to the back teeth, and it is easy to perform the brushing operation.

[0015] Regarding the thickness (base thickness) T1 before and after the head portion 2, it may be adjusted according to the use of the toothbrush and is not particularly limited. Examples of the head portion 2 include a thin hair planting base 6 with a thickness of 4.0 mm or less, preferably 3.0 mm or less, and more preferably 2.5 mm or less.

[0016] Regarding the length (L1) of the head portion 2, it may be appropriately set according to the user. For example, regarding the length of the head portion 2, in the longitudinal direction, it may be 15.0 to 30.0 mm for adults and 13.0 to 20.0 mm for children. Regarding the width of the head portion 2, it may be appropriately set according to the user. For example, it may be 7.5 to 15.5 mm for adults and 7.5 to 13.0 mm for children.

[0017] On the hair planting surface 5 where the hair bundles 20 of the hair planting base 6 project, a plurality of bottomed hair planting holes having a substantially circular cross-section are formed. The opening diameter, depth, number, arrangement form, etc. of the hair planting holes are not limited at all, and are selected from an appropriate range according to various conditions such as the number and material of filaments per hair bundle. The depth of the hair planting holes is appropriately determined according to the thickness T1 of the hair planting base 6. The hair planting holes may basically be straight holes with a circular cross-section. In each hair planting hole, a hair bundle 20 formed by bundling a plurality of filaments and folded in half is planted.

[0018] In the toothbrush 1 of the present invention, the thickness before and after the neck portion 3 is adjusted to 4.0 mm to 5.3 mm. The thickness before and after the neck portion 3 refers to the minimum thickness in the front-rear direction at the center of the longitudinal length between the joint portion G1 of the head portion 2 and the neck portion 3 and the joint portion G2 of the neck portion 3 and the handle portion 4 in a side view. By adjusting the thickness of the neck portion 3 within the above range, it becomes easier to appropriately suppress the deformation of the neck portion 3 during brushing. Note that the joint portion G1 is the point where the bending direction between the head portion and the neck portion in a front view changes from the neck portion or, in the case of a curve and a straight line, the intersection point from the neck portion.

[0019] The axial cross-sectional shape of the neck portion 3 may be a known shape in a toothbrush, such as a substantially circular shape, a substantially elliptical shape, or a substantially rectangular shape, and is not particularly limited.

[0020] In a side view of the neck portion 3 and the head portion 2, the outer shape 11 of the front-side joint portion may be substantially linear, but other shapes are also acceptable and are not particularly limited. For example, as the outer shape 11, by having a linear outer shape in which the neck portion 3 overlaps with the tufted surface 5, a toothbrush in which the neck portion 3 is difficult to deform can be obtained.

[0021] Regarding the length (L2) of the neck portion 3, it may be appropriately set according to the user. For example, for adults, it may be 35.0 to 60.0 mm, and for children, it may be 25.0 to 45.0 mm.

[0022] The handle portion 4 connected to the proximal end side of the neck portion 3 has an outer shape (finger rest regions 7a, 7b) that protrudes in the front and back in the thickness direction in a side view in the finger rest region on the distal end side. In addition, since the finger rest regions 7a and 7b have an outer shape that protrudes in the front and back in the thickness direction, regardless of whether it is a pen grip or a palm grip method, when brushing teeth, it can be firmly grasped with the index finger, thumb, middle finger, etc., preventing slipping and making it easier to perform the brushing operation.

[0023] In a straight toothbrush, when the neck portion does not deform at all, if the user's technique is not high, it becomes difficult for the brush portion to appropriately follow the tooth surface at a substantially right angle, and the effect of toothbrushing cannot be sufficiently obtained. In addition, when the neck portion is easily deformed, it becomes difficult to transmit force to the head portion during brushing, and it becomes particularly difficult to brush teeth with a pen grip. On the other hand, in the toothbrush 1 of the present invention, the neck portion 3 has a predetermined thickness, and the finger rest regions 7a and 7b protruding forward and backward in the thickness direction are provided in the handle portion 4, so that the thickness in the front-rear direction of the connection portion between the neck portion 3 and the handle portion 4 is increased. When a force is applied to the head portion 2 during brushing, the deformation at the neck portion 3 can be appropriately suppressed. Therefore, even when brushing is performed in various ways, it is easy to apply the head portion 2 to the tooth surface at a substantially right angle. Also, since the toothbrush becomes linear, the position of the head portion 2 in the mouth is easy to understand, and it is easy for the user to transmit a desired force to the head portion 2, resulting in excellent brushing operability and easy brushing with the force as expected by the user.

[0024] In particular, regarding the finger rest regions 7a and 7b, when the position of the apex 8a of the front convex portion protruding toward the front side in side view is set closer to the head portion 2 than the apex 8b of the rear convex portion protruding toward the rear side, when a force is applied to the head portion 2 during brushing, the deformation of the neck portion 3 can be more efficiently and appropriately suppressed. In the present invention, the apex 8a of the front convex portion of the finger rest region 7a becomes the joint portion G2 between the neck portion 3 and the handle portion 4.

[0025] The distances (heights) from the central axis A3 of the handle portion 4 to the apex 8a and the apex 8b are not particularly limited. For example, by adjusting them within the range of 4.0 to 7.0 mm, the deformation of the neck portion 3 can be appropriately suppressed while firmly gripping the finger rest portions 7a and 7b with the fingers during brushing.

[0026] Also, the sum (8a + 8b) of the distance from the central axis A3 to the apex 8a and the distance from the central axis A3 to the apex 8b is adjusted so that the difference is 3.0 mm or more and 6.0 mm or less compared to the smallest thickness at the center of the handle portion 4, so that the fingers can be firmly placed on the finger rest regions 7a and 7b.

[0027] On the handle portion 4, at a position excluding the finger contact regions 7a and 7b, it has a convex outer shape 9 on the rear side of the toothbrush in side view. Thus, when gripping in either the pen grip or palm grip method, it easily fits the hand and becomes stable, is difficult to slip during brushing, makes it easier to apply the intended force by the user, and has an excellent toothbrushing operability effect that makes brushing easier.

[0028] The position of the apex of the convex outer shape 9 only needs to be provided between the finger contact portion 7b of the handle portion 4 and the end. However, by being provided such that the thickness is smallest near the center in the longitudinal direction of the handle portion 4, the area where the base of the finger or the palm fits becomes larger, and it becomes easier to stably grip the handle portion. Also, the position of the apex of the convex outer shape 9 in the front and rear in the thickness direction only needs to be near the center in the longitudinal direction of the handle portion 4, but there is no particular limitation.

[0029] In the toothbrush 1 according to the present invention, when the central axis A1 of the head portion 2, the central axis A2 of the neck portion 3, and the central axis A3 of the handle portion 4 are defined as straight lines passing through the centers in the front and rear in the thickness direction at the longitudinal center positions P1, P2, P3 of each part and parallel to the tufted surface in side view, By adjusting the central axis A2 of the neck portion 3 to be displaced toward the rear side of the toothbrush with respect to both the central axis A1 of the head portion 2 and the central axis A3 of the handle portion 4, when a force is applied to the head portion 2 during brushing, the neck portion 3 is less likely to deform, and it becomes easier for the user to grasp the force applied to the head portion 2.

[0030] The longitudinal center positions P1, P2, P3 are the center positions of the length L1 of the head portion 2, the length L2 of the neck portion 3, and the length L3 of the handle portion 4 in side view, and refer to the center of gravity (drawing center of gravity) of the cross-sectional drawing in the cross-section of each part.

[0031] In the toothbrush 1 of the present invention, the center position P2 of the neck portion 3 only needs to be arranged on the rear side with respect to the center position P1 of the head portion 2 in the front and rear in the thickness direction. By being adjusted as described above, the outer shape of the toothbrush is easily adjusted to a linear shape, making it easy to grip in either the pen grip or palm grip method. Also, when a force is applied to the head portion 2, it becomes easier to moderately suppress deformation of the neck portion 3.

[0032] Also, the positions of the center position P1 of the head portion 2 and the center position P3 of the handle portion 4 may be substantially the same or different in the front-rear thickness direction. When the positions of the center position P1 of the head portion 2 and the center position P3 of the handle portion 4 are substantially the same, the outer shape of the toothbrush 1 is in the most linear shape, and the central axis A1 of the head portion 2 and the central axis A3 of the handle portion 4 are in a state of being substantially aligned with respect to the front-rear thickness direction. On the other hand, when the positions of the center position P1 of the head portion 2 and the center position P3 of the handle portion 4 are different, the central axis A1 of the head portion 2 and the central axis A3 of the handle portion 4 are arranged offset with respect to the front-rear thickness direction. When the positions of the center position P1 of the head portion 2 and the center position P3 of the handle portion 4 are different, it is preferably adjusted within a range of 3 mm or less.

[0033] The handle portion 4 may have a linear outer shape 10 of a predetermined length substantially parallel to the central axis A3 of the handle portion 4 on the front side of the toothbrush in a side view at a position excluding the finger contact regions 7a and 7b on the tip side. The linear outer shape 10 may be provided between the base end side of the finger contact region 7a on the front side and the base end side of the handle portion 4. In the handle portion 4, by making the linear outer shape 10 longer, the outer shape of the toothbrush 1 becomes a linear toothbrush, and there are advantages that the handle portion 4 can be more stably and easily gripped in either the pen grip or palm grip method, and it is easy to grasp the position of the head portion 2 in the mouth.

[0034] The axial cross-sectional shape of the handle portion 4 may be a known shape in a toothbrush, such as a substantially circular shape, a substantially elliptical shape, or a substantially rectangular shape, and is not particularly limited. Further, the area of the axial cross-sectional shape may be constant or may be adjusted to change in the longitudinal direction. For example, by forming the axial cross-sectional shape into a substantially rectangular shape with rounded corners, having a wider width than the thickness of the handle portion 4, and configuring the axial cross-sectional area to gradually increase toward the central portion compared to the tip side of the handle portion 4, it is possible to greatly adjust the area that fits in the palm in either the pen grip or palm grip method, making it easier to stably hold the toothbrush 1, but it is not limited to this shape. The thickness of the handle portion 4 in the front-rear direction is not particularly limited. Further, as shown in FIG. 1, the rear end of the handle portion 4 may be arranged to be shifted rearward with respect to the central axis A3, or may be arranged such that the central axis A3 becomes the center of the axial cross-section of the rear end.

[0035] The length (L3) of the handle portion 4 is not particularly limited as long as it is adjusted within the same range as the handle portion of a commercially available toothbrush.

[0036] Further, as toothbrushes according to another aspect of the present invention, the following toothbrushes 1A and 1B can be mentioned. (a) A toothbrush 1A including a head portion 2 having a substantially flat bristle planting surface 5 on which the bristle bundles 20 are planted, a neck portion 3 connected to the proximal end side of the head portion 2, and a handle portion 4 connected to the proximal end side of the neck portion 3, wherein the front-rear thickness along the bristle bundle protruding direction of the head portion 2 is 2 to 4 mm, the front-rear thickness of the neck portion 3 is 4.0 to 5.3 mm, when a straight line A4 is connected between the center C1 of the front-rear thickness at the tip of the head portion 2 and the center C2 of the front-rear thickness at the rear end of the handle portion 4, the straight line A4 is within the shape of the handle portion 4, the handle portion 4 has outer shapes (finger contact regions) 7a and 7b protruding in the front-rear direction in the thickness direction in a side view in the finger contact region on the tip side, and has an outer shape 9 that is convex inward on the rear surface side of the toothbrush in a side view at positions excluding the finger contact regions 7a and 7b. Toothbrush 1A (Fig. 2).

[0037] Similar to the toothbrush 1, the toothbrush 1A is excellent in brushing operability, being easy to grip without slipping during brushing in either a pen grip or a palm grip method, and being easy to brush with the force as expected by the user even when force is applied to the head portion 2.

[0038] The configuration of each part of the head portion 2, the neck portion 3, and the handle portion 4 of the toothbrush 1A may be the same as that of the toothbrush 1. In the toothbrush 1A, as shown in Fig. 2, when the center C1 in the front - rear direction in the thickness direction at the tip of the head portion 2 and the center C2 in the front - rear direction in the thickness direction at the rear end of the handle portion 4 are connected by a straight line L4, the straight line L4 is configured to be within the shape of the handle portion 4. With such a configuration, the outer shape of the toothbrush 1A becomes linear, and when force is applied to the head portion 2 in either a pen grip or a palm grip method, the deformation of the neck portion 3 can be appropriately suppressed, making it easier for the user to adjust the force during brushing.

[0039] (b) A toothbrush 1B comprising a head portion 2 having a substantially flat implanting surface 5 on which the tuft 20 is implanted, a neck portion 3 connected to the proximal end side of the head portion 2, and a handle portion 4 connected to the proximal end side of the neck portion 3, The front - rear thickness along the tuft protruding direction of the head portion 2 is 2 - 4 mm, The front - rear thickness of the neck portion 3 is 4.0 - 5.3 mm, The handle portion 4 has outer - shape protrusions (finger - resting regions) 7a, 7b protruding in the front - rear direction in the thickness direction in a side view at the finger - resting region on the tip side, and has an outer - shape 9 that is convex inward on the rear side of the toothbrush in a side view at positions excluding the finger - resting regions 7a, 7b, When a rectangle E is drawn consisting of a straight line L5 that is substantially parallel to the tufted surface 5 and contacts the apex 8a of the front convex portion protruding to the front side of the finger-touching area 7a in a side view, a straight line L6 that is substantially parallel to the tufted surface 5 and contacts the apex 8b of the rear convex portion protruding to the rear side of the finger-touching area 7b, a straight line L7 that perpendicularly intersects L5 and L6 and contacts the tip of the head portion 2 of the toothbrush 1B, and a straight line L8 that perpendicularly intersects L5 and L6 and contacts the rear end of the brush portion 4 of the toothbrush 1B, the entire toothbrush 1B is configured to fit within the rectangle E. Toothbrush 1B (FIG. 3).

[0040] Similar to the toothbrush 1, the toothbrush 1B is excellent in brushing operability, being easy to grip without slipping during brushing in either the pen-grip or palm-grip method, and being easy to brush with the force as expected by the user even when a force is applied to the head portion 2.

[0041] The configurations of each part of the head portion 2, the neck portion 3, and the handle portion 4 of the toothbrush 1B may be the same as those of the toothbrush 1.

[0042] Also, as shown in FIG. 3, in a side view, the toothbrush 1B is configured such that when a rectangle E is drawn consisting of a straight line L5 that is substantially parallel to the tufted surface 5 and contacts the apex 8a of the front convex portion protruding to the front side of the finger-touching area 7a, a straight line L6 that is substantially parallel to the tufted surface 5 and contacts the apex 8b of the rear convex portion protruding to the rear side of the finger-touching area 7b, a straight line L7 that perpendicularly intersects L5 and L6 and contacts the tip of the head portion 2 of the toothbrush 1B, and a straight line L8 that perpendicularly intersects L5 and L6 and contacts the rear end of the handle portion 4 of the toothbrush 1B, the entire toothbrush 1B fits within the rectangle E. With the above configuration, when a force is applied to the head portion 2 in either the pen-grip or palm-grip method, the deformation of the neck portion 3 can be moderately suppressed, making it easier for the user to adjust the force during brushing.

[0043] As the materials for the head portion 2, the neck portion 3, and the handle portion 4, any known resin used in toothbrushes may be used. For example, polyethylene terephthalate (PET), polycarbonate (PC), acrylonitrile butadiene styrene (ABS), acrylonitrile styrene copolymer (AS resin), polystyrene (PS), polyethylene (PE), polypropylene (PP), etc. may be mentioned, but there is no particular limitation.

[0044] The head portion 2, the neck portion 3, and the handle portion 4 may each be made of a different material. Further, the handle portion 4 may have a two-layer structure of a base material portion and a covering portion.

[0045] Regarding the manufacturing method of the toothbrushes 1, 1A, and 1B having the above-described configuration, any known method may be used, and there is no particular limitation. For example, with the mold having voids for the head portion 2, the neck portion 3, and the handle portion 4 being clamped, resin is injected into the molding space of this mold to integrally mold the head portion 2, the neck portion 3, and the handle portion 4, thereby manufacturing a toothbrush. Also, the primary molded product forming the head portion 2 and the neck portion 3 is clamped in a secondary molding mold, and another resin is injected into the molding space having voids for the handle portion 4, thereby manufacturing the toothbrushes 1, 1A, and 1B in which the resin types are different between the head portion 2 and the neck portion 3 and the handle portion 4.

[0046] In this way, the tufts 4 may be implanted in the implanting holes 20 of the implanting base 5 provided in the head portion 2 of the obtained toothbrushes 1, 1A, and 1B by a known method. Also, regarding the material of the brush hairs constituting the tufts 4, any known material used in toothbrushes may be used, and there is no particular limitation.

[0047] As described above, the embodiments of the present invention have been explained. However, the present invention is not limited to such examples, and it goes without saying that the present invention can be implemented in various forms without departing from the gist of the present invention.

Example

[0048] (Example 1) Using 3D CAD software (Dassault Systèmes' "Solidworks"), a toothbrush 1 (excluding the tuft 20) having the outer shape shown in FIG. 1 was created. The configuration of each part is as follows. Head part 2 (material: PET): Thickness (T1) 3 mm, length (L1) 21.3 mm, width 7.6 mm Neck part 3 (material: PET): Minimum thickness 4.5 mm, length (L2) 50.0 mm, width 4.0 mm Handle part 4 (material: PET): Thickness 7.2 mm, length (L3) 180 mm, Distance from the rear end of the handle part 4 to the vertex 8b: 108.0 mm Height of the vertex 8a of the finger rest area 7a on the front side (distance from the center line A3 of the handle part 4) 5.6 mm Height of the vertex 8b of the finger rest area 7b on the rear side (distance from the center line A3 of the handle part 4) 5.8 mm Difference between the center axis A2 of the neck part 3 and the center axis A1 of the head part 2 in the front - rear direction of the thickness: 0.8 mm Difference between the center axis A3 of the handle part 4 and the center axis A1 of the head part 2 in the front - rear direction of the thickness: 0.6 mm

[0049] (Example 2) A toothbrush 1 (excluding the tuft 20) having the same configuration as that of Example 1 was created, except that the height of the vertex 8a of the finger rest area 7a on the front side was increased by 0.5 mm compared to Example 1.

[0050] (Example 3) A toothbrush 1 (excluding the tuft 20) having the same configuration as that of Example 1 was created, except that the height of the vertex 8b of the finger rest area 7b on the rear side was increased by 0.5 mm compared to Example 1.

[0051] In addition, as shown in FIG. 2, for all the toothbrushes of Examples 1 to 3, when the center C1 in the front-rear direction of the thickness at the tip of the head portion 2 and the center C2 in the front-rear direction of the thickness at the rear end of the handle portion 4 are connected by a straight line A4, the straight line A4 is configured to fit within the shape of the handle portion 4. Also, as shown in FIG. 3, a straight line L5 that is substantially parallel to the bristle planting surface 5 and contacts the apex 8a of the front convex portion protruding to the front side of the finger placement area 7a in a side view, a straight line L6 that is substantially parallel to the bristle planting surface 5 and contacts the apex 8b of the rear convex portion protruding to the rear side of the finger placement area 7b, a straight line L7 that is perpendicular to L5 and L6 and contacts the tip of the head portion of the toothbrush 1, and a straight line L8 that is perpendicular to L5 and L6 and contacts the rear end of the handle portion 4 of the toothbrush 1. When a rectangle E composed of these lines is drawn, the entire toothbrush 1 is configured to fit within the rectangle E.

[0052] (Comparative Example 1) As shown in FIG. 4, except that the difference between the central axis A2 of the neck portion 3 and the central axis A1 of the head portion 2 in the front-rear direction of the thickness is 0.8 mm, Difference between the central axis A3 of the handle portion 4 and the central axis A1 of the head portion 2 in the front-rear direction of the thickness: 2.1 mm A toothbrush 1C (excluding the bristle bundle 20) having the same configuration as that of Example 1 was created, except that these were changed. In the toothbrush 1C, the central axis A2 of the neck portion 3 is adjusted to the front side of the central axis A1 of the head portion 2 and the central axis A3 of the handle portion 4.

[0053] (Comparative Example 2) As shown in FIG. 5, an S-shaped toothbrush 1D having the same configuration as that of Example 1 was created, except that the height of the apex of the inner convex outer shape 9 (the difference from the end portion on the rear side of the handle portion 4) in the front-rear direction of the thickness was set to 5.0 mm. As shown in FIG. 11, for the toothbrush 1D of Comparative Example 2, when the center C1 in the front-rear direction of the thickness at the tip of the head portion 2 and the center C2 in the front-rear direction of the thickness at the rear end of the handle portion 4 are connected by a straight line L4, the straight line L4 does not fit within the shape of the handle portion 4. Also, as shown in Fig. 12, when a rectangle E is drawn, which consists of a straight line L5 that is substantially parallel to the bristle planting surface 5 and contacts the apex 8a of the front convex portion protruding to the front side of the finger rest area 7a in a side view, a straight line L6 that is substantially parallel to the bristle planting surface 5 and contacts the apex 8b of the rear convex portion protruding to the rear side of the finger rest area 7b, a straight line L7 that intersects perpendicularly to L5 and L6 and contacts the tip of the head portion 2 of the toothbrush 1D, and a straight line L8 that intersects perpendicularly to L5 and L6 and contacts the rear end of the brush portion 4 of the toothbrush 1D, the entire toothbrush 1D does not fit within the rectangle E.

[0054] (Comparative Example 3) As shown in Fig. 6, a toothbrush 1E having the same configuration as that of Example 1 was created, except that the outer shape of the finger rest area 7b on the rear side of the handle portion 4 was made linear in a side view and the rear convex portion was eliminated.

[0055] (Comparative Example 4) As shown in Fig. 7, a toothbrush 1F having the same configuration as that of Example 1 was created, except that the outer shapes of the finger rest areas 7a and 7b on the front side and the rear side of the handle portion 4 were made linear in a side view and the front convex portion and the rear convex portion were eliminated.

[0056] (Comparative Example 5) As shown in Fig. 8, a toothbrush 1G having the same configuration as that of Example 1 was created, except that the outer shape of the rear side of the handle portion 4 of the toothbrush was made linear in a side view.

[0057] (Comparative Example 6) As shown in Fig. 9, a toothbrush 1H having the same configuration as that of Example 1 was created, except that the minimum thickness of the neck portion 3 was changed to 3.9 mm and the surface of the bristle planting surface 5 of the head portion 2 and the front side of the neck portion 3 were not parallel in a side view.

[0058] (Comparative Example 7) As shown in Fig. 10, a toothbrush 1I having the same configuration as that of Example 1 was created, except that the minimum thickness of the neck portion 3 was changed to 5.4 mm.

[0059] (Test Example 1) The toothbrushes created in Examples 1 to 3 and Comparative Examples 1 to 7 were subjected to linear stress analysis using 3D CAD software for mechanical design purposes ("Solidworks") to calculate stress, deformation, and strain. Each condition is as follows. Fixed position: Near the center of gravity of the toothbrush (an ellipse of 15 mm and R3.5) Load: 1 N applied to the central part of the head part 2 Stress: (N / m 2 ) Displacement: Composite displacement (displacement at the tip of the head part 2) Strain (equivalent) The obtained results are shown in Table 1.

[0060]

Table 1

[0061] From the results shown in Table 1, it can be seen that for the toothbrushes obtained in Examples 1 to 3, when a stress of 1 N is applied to the central part of the head part 2, the displacement amount is adjusted within the range of 0.578 to 0.595 mm, and the deformation of the neck part 3 is appropriately suppressed.

[0062] On the other hand, it can be seen that for the toothbrush 1C (Comparative Example 1) in which the position of the central axis A2 of the neck part 3 is arranged on the front side in the thickness direction compared to the central axis A1 of the head part 2, the displacement amount is large and the neck part 3 is easily deformed. The S-shaped toothbrush 1D (Comparative Example 2), which is a type of conventional toothbrush, has a large displacement amount and the neck part 3 is easily deformed. Regarding the toothbrush 1E (Comparative Example 3), which is a type of conventional linear toothbrush and has no convex part on the outer shape of the finger rest area 7b on the rear side of the handle part 4, and the toothbrush 1F (Comparative Example 4), which is linear and has no convex part on the finger rest areas 7a and 7b on the front and rear sides of the handle part 4, it can also be seen that the displacement amount is large and the neck part 3 is easily deformed. Regarding the toothbrush 1G (Comparative Example 5) without the inner convex shape 9 in the handle part, it can also be seen that the displacement amount is large and the neck part 3 is easily deformed. The toothbrush 1H (Comparative Example 6) with a small thickness of the neck portion 2 has the largest displacement amount. On the other hand, the toothbrush 1I (Comparative Example 7) with a large thickness of the neck portion 2 has the smallest displacement amount, indicating that the neck portion 3 is very difficult to deform.

[0063] (Test Example 2: Evaluation of usability) Regarding the toothbrushes obtained in Examples 1 to 3 and Comparative Examples 1 to 7, the ease of holding, the non-slip property of the handle portion, and the overall ease of toothbrushing were evaluated as follows. (Ease of holding) The ease of holding was evaluated by gripping the vicinity of the finger contact portion with a pen grip (pencil hold) and performing a brushing motion with repeated strokes. Evaluation criteria 〇: It was considered 〇 when it could be stably gripped. △: It was considered △ when there was a lack of stability. ×: It was considered × when it fell from the hand during the brushing motion. (Non-slip property of the handle portion) The non-slip property of the handle portion was evaluated by gripping the vicinity of the finger contact portion with a pen grip (pencil hold) and performing a brushing motion with repeated strokes. Evaluation criteria 〇: It was considered 〇 when the handle fit the hand and the brushing motion could be performed. △: It was considered △ when a lack of fit was felt. ×: It was considered × when it fell from the hand during the brushing motion. (Overall ease of toothbrushing) The overall ease of toothbrushing was evaluated by freely gripping the toothbrush and brushing near the first molar. Evaluation criteria 〇: It was considered 〇 when it could be comfortably brushed with appropriate deflection. △: It was considered △ when it was difficult to grasp the deflection. ×: It was considered × when the deflection could not be grasped or it was felt that it was almost impossible to deflect and difficult to brush. Note that each of the above evaluations was based on the result of a consensus among 5 panelists.

[0064] The obtained results are shown in Table 1. From the results shown in Table 1, the toothbrushes created in Examples 1 to 3 were all easy to hold the handle, difficult for the handle to slip, and easy to perform overall toothbrushing. On the other hand, the toothbrushes 1C to 1I created in Comparative Examples 1 to 7 were all inferior to those in Examples 1 to 3 in terms of the ease of overall toothbrushing. In addition, the toothbrushes 1E to 1G in Comparative Examples 3 to 5 were easy for the handle to slip, and furthermore, the toothbrush 1F in Comparative Example 4 was difficult to hold.

[0065] Also, compared with the S-shaped toothbrush 1D of Comparative Example 2 where the straight line L4 does not fit within the shape of the handle portion 4 as shown in FIG. 11 and the entire toothbrush does not fit within the rectangle E as shown in FIG. 12, the toothbrushes obtained in Examples 1 to 3 having the configurations shown in FIGS. 2 or 3 had the displacement amount of the head portion 2 appropriately suppressed, were easy to hold the handle, difficult for the handle to slip, and easy to perform overall toothbrushing.

Explanation of Signs

[0066] 1, 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H, 1I Toothbrushes 2 Head portion 3 Neck portion 4 Handle portion 5 Bristle implantation surface 6 Bristle implantation base 7a, 7b Finger contact areas 8a Vertex of the front convex portion 8b Vertex of the rear convex portion 9 Outer shape of the inner convex 10 Linear outer shape 20 Bristle tufts 11 Outer shape of the joint portion between the neck portion 3 and the head portion 2 A1 Central axis of the head portion 2 A2 Central axis of the neck portion 3 A3 Central axis of the handle portion 4 P1 Longitudinal center position of the head portion 2 P2 Longitudinal center position of the neck portion 3 Longitudinal center position of the P3 handle part 4 Center in the front - rear thickness direction at the tip of the C1 head part 2 Center in the front - rear thickness direction at the rear end of the C2 handle part 4 Length of the C1 head part 2 in the longitudinal direction Length of the C2 neck part 3 in the longitudinal direction Length of the C3 handle part 4 in the longitudinal direction Straight line connecting the center C1 in the front - rear thickness direction at the tip of the head part 2 and the center C2 in the front - rear thickness direction at the rear end of the handle part 4 Straight line substantially parallel to the flocked surface 5 contacting the apex 8a of the front convex part protruding to the front side of the finger - contact area 7a Straight line substantially parallel to the flocked surface 5 contacting the apex 8b of the rear convex part protruding to the rear side of the finger - contact area 7b Straight line contacting the tip of the head part of the toothbrush 1 perpendicular to L5 and L6 Straight line contacting the rear end of the brush part 4 perpendicular to L5 and L6 Thickness of the head part 2 in the front - rear direction Joint part of the head part 2 and the neck part 3 Joint part of the neck part 3 and the handle part 4

Claims

Claim 1 A toothbrush comprising a head portion having a substantially flat tuft-planting surface on which tufts are planted, a neck portion connected to the proximal end side of the head portion, and a handle portion connected to the proximal end side of the neck portion, wherein the front-to-back thickness along the tuft protruding direction of the head portion is 2 to 4 mm, the front-to-back thickness of the neck portion is 4.0 to 5.3 mm, when the central axes of the head portion, the neck portion, and the handle portion are defined as straight lines passing through the centers in the front-to-back thickness direction at the longitudinal center positions of the respective portions and parallel to the tuft-planting surface in a side view, the central axis of the neck portion is shifted toward the rear surface side of the toothbrush with respect to both the central axis of the head portion and the central axis of the handle portion, the handle portion has an outer shape that protrudes in the front-to-back thickness direction in a side view in the finger-contact region on the distal end side, and has an outer shape that is convex inward toward the rear surface side of the toothbrush in a side view at positions excluding the finger-contact region, a toothbrush. Claim 2 The toothbrush according to claim 1, wherein the handle portion has a linear outer shape with a predetermined length substantially parallel to the central axis of the handle portion on the front surface side of the toothbrush in a side view at positions excluding the finger-contact region on the distal end side. Claim 3 The toothbrush according to claim 1, wherein the central axis of the head portion and the central axis of the handle portion are substantially coincident. Claim 4 The toothbrush according to claim 1, wherein the neck portion has a linear outer shape that overlaps the tuft-planting surface on the front surface side of the toothbrush in a side view. Claim 5 The toothbrush according to claim 1, wherein the apex of the front convex portion protruding on the front surface side in a side view in the finger-contact region of the handle portion is set closer to the head portion than the apex of the rear convex portion protruding on the rear surface side.

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