CN114025643A

CN114025643A - Tooth brush

Info

Publication number: CN114025643A
Application number: CN202080044714.6A
Authority: CN
Inventors: 蜂须贺良祐
Original assignee: Lion Corp
Current assignee: Lion Corp
Priority date: 2019-06-28
Filing date: 2020-06-23
Publication date: 2022-02-08
Anticipated expiration: 2040-06-23
Also published as: JPWO2020262346A1; KR20220029539A; WO2020262346A1; JP7466539B2; TW202100062A; CN114025643B

Abstract

The invention aims to provide a toothbrush capable of sufficiently reducing excessive brushing pressure. At least a part of the head and the neck is formed of a hard resin, and the head and the neck are provided with: a deformation part (70) which is arranged on the holding part and deforms due to external force in a first direction orthogonal to the hair planting surface; a first region which is disposed on the distal end side of the deformation portion and is not deformed by an external force in a first direction; and a second region which is disposed on a rear end side of the deformation portion and which is not deformed by an external force in the first direction, wherein the grip portion is formed of a hard resin at least in a part of a cross section orthogonal to the longitudinal direction from at least a front end of the grip portion to the second region in the longitudinal direction, and the deformation portion includes: a flat plate-shaped hard portion (70H) formed of a hard resin; and a soft portion (70E) formed of a soft resin and covering at least a part of the hard portion, wherein the occupancy rate of the cross-sectional area of the hard portion with respect to the cross-sectional area of the deformed portion is 35% or less in the entire longitudinal direction, and a relationship of T/W < 1 is satisfied in the entire longitudinal direction when T is a thickness of the hard portion in the first direction and W is a width of the hard portion in the second direction.

Description

Tooth brush

Technical Field

The present invention relates to toothbrushes.

The present application claims priority based on japanese patent application No. 2019-121415, filed in japan on 28/6/2019, and the contents of which are incorporated herein by reference.

Background

The proportion of people with 20 teeth at age 80 is about 5, while the proportion of caries (root caries) in older people is increasing. Root caries is a tooth decay of dentin exposed by gingival atrophy, and the tooth decay progresses rapidly because the constitutional ratio of organic components is higher in dentin than in enamel. One of the causes of the gingival atrophy is excessive brushing in which brushing is performed at a brushing pressure higher than an appropriate value.

Conventionally, as a toothbrush for reducing an excessive brushing pressure, for example, a toothbrush described in patent document 1 is disclosed. In the toothbrush described in patent document 1, when the toothbrush is gripped by a palm grip method for brushing, a part made of a thermoplastic resin among parts gripped by a thumb and an index finger of the handle portion is formed in a U shape that is open to the hair-implanted surface side, and the periphery of the part made of the thermoplastic resin is covered with a soft resin such as an elastomer material.

The toothbrush having the above structure disclosed in patent document 1 includes the following: by applying the load of the head not only to the neck but also to the above-mentioned part of the handle, the gum is not damaged, and the excessive brushing pressure is reduced while providing a soft and comfortable operability to the teeth and gum.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2000-004944

Disclosure of Invention

Problems to be solved by the invention

However, in the conventional toothbrush described above, the elastic force is locally applied in consideration of the filling property of the soft resin while maintaining the mechanical strength, and it cannot be said that the excessive reduction of the brushing pressure is sufficient.

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a toothbrush which can provide soft and comfortable operability to teeth and gums without damaging gums, and can sufficiently reduce excessive brushing pressure.

Means for solving the problems

According to a first aspect of the present invention, there is provided a toothbrush comprising: a head portion provided on a distal end side in a longitudinal direction and having a hair-setting surface; a grip portion disposed on a rear end side of the head portion; and a neck portion disposed between the bristle surface and the grip portion, at least a part of the head portion and the neck portion being formed of a hard resin, the toothbrush including: a deformation portion disposed on the holding portion and deformed by an external force in a first direction orthogonal to the flocked surface; a first region which is disposed on the distal end side of the deformation portion and is not deformed by an external force in the first direction; and a second region that is disposed on the rear end side of the deformation portion and is not deformed by an external force in the first direction, wherein the grip portion is formed of the hard resin at least in a part of a cross section orthogonal to the long axis direction from at least a front end of the grip portion to the second region in the long axis direction, and the deformation portion includes: a flat plate-shaped hard portion formed of the hard resin; and a soft portion formed of a soft resin and covering at least a part of the hard portion, wherein an occupancy rate of a cross-sectional area of the hard portion in a cross-section orthogonal to the longitudinal direction with respect to a cross-sectional area of the deformed portion is 35% or less over the entire longitudinal direction, and a relationship of T/W < 1 is satisfied over the entire longitudinal direction when a thickness of the hard portion in the first direction is T and a width of the hard portion in a second direction orthogonal to the longitudinal direction and the first direction is W.

In the toothbrush according to one aspect of the present invention, the hard portion includes: a first thickened portion which is connected to the first region so that a thickness in the first direction gradually increases toward a front end side in the longitudinal direction; and a second thickened portion which is connected to the second region with a thickness in the first direction gradually increasing toward a rear end side in the longitudinal direction.

In the toothbrush according to one aspect of the present invention, a maximum thickness of the second thickened portion is smaller than a maximum thickness of the first thickened portion.

In the toothbrush according to one aspect of the present invention, the width of the rear end portion of the hard portion connected to the second region is smaller than the width of the front end portion connected to the first region.

In the toothbrush according to one aspect of the present invention, the minimum thickness of the hard portion in the first direction is 0.5mm to 2.0 mm.

In the toothbrush according to one aspect of the present invention, the length of the deformation portion in the longitudinal direction is 15mm or more.

In the toothbrush according to one aspect of the present invention, the maximum thickness of the head in the first direction is 2.0mm to 4.0 mm.

In the toothbrush according to one aspect of the present invention, the minimum thickness of the neck portion in the first direction and the minimum width of the neck portion in the second direction are 3.0mm to 4.5 mm.

Effects of the invention

The present invention can provide a toothbrush which can provide gentle and comfortable operability to teeth and gums without damaging gums, and can sufficiently reduce excessive brushing pressure.

Drawings

Fig. 1 is a view showing a first embodiment of the present invention, and is a front view of a toothbrush 1.

Fig. 2 is a sectional view of the toothbrush 1 cut by a plane including the center in the width direction.

Fig. 3 is a front view of the hard portion H constituting the toothbrush 1.

Fig. 4 is a sectional view taken along line a-a of fig. 1.

Fig. 5 is a partially enlarged front view of the hard portion 70H in the hard portion H.

Fig. 6 is a side view of fig. 5.

Fig. 7 is a view showing the toothbrush 1 of the second embodiment, (a) is a front view including a sectional view partially cut with a plane including a center in the thickness direction, and (B) is a sectional view partially cut with a plane including a center in the width direction, and is a rear view including a sectional view partially cut with a plane including a center in the thickness direction.

Detailed Description

Hereinafter, an embodiment of the toothbrush of the present invention will be described with reference to fig. 1 to 7.

The following embodiments are illustrative of one embodiment of the present invention, and are not intended to limit the present invention, and may be modified as desired within the scope of the technical idea of the present invention. In the drawings below, the scale, the number, and the like of each structure are different from those of the actual structure in order to facilitate understanding of each structure. In the following description, the direction perpendicular to the flocked surface in a side view is referred to as the thickness direction, the flocked surface side in the thickness direction is referred to as the front surface side, and the side opposite to the flocked surface is referred to as the back surface side.

[ first embodiment ]

Fig. 1 is a front view of a toothbrush 1 of a first embodiment. Fig. 2 is a cross-sectional view of the toothbrush 1 cut along a plane including the center in the width direction (vertical direction in fig. 1). Fig. 3 is a front view of the hard portion H constituting the toothbrush 1.

The toothbrush 1 of the present embodiment includes: a head 10 which is disposed on a distal end side in a longitudinal direction (hereinafter, simply referred to as a distal end side) and into which a bundle of bristles (not shown) is implanted; a neck portion 20 extending to a rear end side in the longitudinal direction of the head portion 10 (hereinafter, simply referred to as a rear end side); and a grip 30 extending to the rear end side of the neck 20 and having a deformation portion 70 (hereinafter, the head 10, the neck 20, and the grip 30 are collectively referred to as a handle body 2).

The toothbrush 1 of the present embodiment is a molded body in which a hard portion H made of a hard resin and a soft portion E made of a soft resin are integrally molded. The hard portion H constitutes at least a part of each of the head 10, the neck 20, the grip portion 30, and the deformable portion 70. The soft portion E constitutes a part of each of the grip portion 30 and the deforming portion 70. More specifically, the head 10 and the neck 20 of the present embodiment are each formed of a hard resin, but may be formed of a part of the soft resin, for example, a part of the surface may be covered with the soft resin. A part of the grip portion 30 including the deformable portion 70 of the present embodiment is formed of both a hard resin and a soft resin (details will be described later).

[ head part 10]

The head 10 has a flocked surface 11 on one side in the thickness direction (direction orthogonal to the paper surface of fig. 1). Hereinafter, a direction orthogonal to the thickness direction and the longitudinal direction is referred to as a width direction (or a side direction as appropriate). A plurality of implanted holes 12 are formed in the implanted surface 11. A tuft (not shown) having bristles is planted in the planting hole 12.

The width of the head 10, that is, the length in the width direction parallel to the hair-planted surface 11 on the front side and orthogonal to the longitudinal direction (hereinafter, simply referred to as width) is not particularly limited, and is preferably 7mm to 13mm, for example. If the upper limit value is not less than the lower limit value, the area of the implanted hair bundle can be sufficiently secured, and if the lower limit value is not more than the upper limit value, the operability in the oral cavity can be further improved.

The length of the head 10 in the longitudinal direction (hereinafter simply referred to as length) is not particularly limited, and is preferably 10mm to 33mm, for example. If the length of the head 10 is equal to or greater than the lower limit, the area of the implanted hair bundle can be sufficiently secured, and if the length is equal to or less than the upper limit, the operability in the oral cavity can be further improved. The boundary between the neck portion 20 and the head portion 10 in the longitudinal direction of the present embodiment is a position where the width of the neck portion 20 is the minimum value in the direction from the neck portion 20 toward the head portion 10. When the region where the width of the neck portion 20 is the minimum value exists at a constant length (when the position where the width of the neck portion 20 is the minimum value is not one), the boundary in the longitudinal direction between the neck portion 20 and the head portion 10 is the position closest to the head distal end side where the width of the neck portion 20 is the minimum value.

The length of the head 10 in the thickness direction (hereinafter, simply referred to as thickness) may be determined in consideration of the material and the like, and is preferably 2.0mm or more and 4.0mm or less. If the thickness of the head 10 is equal to or greater than the lower limit, the strength of the head 10 can be further improved. When the thickness of the head 10 is equal to or less than the upper limit value, the reach to the deep of the molar teeth can be improved, and the operability in the oral cavity can be further improved.

The tufts are formed by bundling a plurality of bristles. The length from the bristle surface 11 to the tip of the tuft (bristle length) is determined in consideration of the waist of the tuft, and is, for example, 6 to 13 mm. All tufts may be of the same bristle length or may be different from one another.

The thickness of the tufts (tuft diameter) may be determined in consideration of the waist of the hair required for the tufts, and is, for example, 1 to 3 mm. All of the tufts may be of the same tuft diameter or may be different from one another.

Examples of the bristles constituting the bristle bundle include bristles (tapered bristles) having a diameter gradually decreasing toward the bristle tips and sharpened bristle tips, bristles (straight bristles) having a diameter substantially the same from the bristle surface 11 toward the bristle tips, and the like. Examples of the straight bristles include bristles having flat bristle tips substantially parallel to the bristle-implanted surface 11 and bristles having hemispherical bristle tips.

Examples of the material of the brush include polyamides such as 6-12 nylon (6-12NY) and 6-10 nylon (6-10NY), polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN) and polybutylene naphthalate (PBN), polyolefins such as polypropylene (PP), polyolefin elastomers and styrene elastomers. These resin materials may be used singly or in combination of two or more. Further, as the bristles, there may be mentioned polyester bristles having a multilayer core structure having a core portion and at least 1 or more layers of sheath portions provided outside the core portion.

The cross-sectional shape of the brush is not particularly limited, and may be circular such as a perfect circle and an ellipse, polygonal, star-shaped, clover-shaped, or the like. The cross-sectional shape of all the bristles may be the same or different.

The thickness of the brush may be determined in consideration of the material, and when the cross section is circular, it is, for example, 6 to 9 mils (1 mil: 1/1000 inch: 0.025 mm). In addition, a plurality of bristles having different thicknesses may be optionally combined in consideration of a use feeling, a brushing feeling, a cleaning effect, durability, and the like.

[ neck part 20]

From the viewpoint of operability, the length of the neck portion 20 is preferably 40mm or more and 70mm or less.

For example, the width of the neck portion 20 is formed to gradually increase from a position where the width becomes a minimum value toward the rear end side. The neck portion 20 in the present embodiment is formed to be gradually larger from the position where the width is the minimum toward the rear end side. The thickness of the neck portion 20 is formed to gradually increase from the position where the thickness is smallest toward the rear end side.

The neck portion 20 preferably has a width and a thickness of 3.0mm to 4.5mm at the position where the width and the thickness are smallest. If the width and thickness of the neck portion 20 at the minimum position are equal to or greater than the lower limit values, the strength of the neck portion 20 can be further improved, and if the width and thickness are equal to or less than the upper limit values, the lips are easily closed, the reach to the molar teeth can be improved, and the operability in the oral cavity can be further improved. The width and thickness of the neck portion 20 formed to be gradually increased from the position where the neck portion becomes the minimum toward the rear end side may be appropriately determined in consideration of the material and the like.

The front side of the neck portion 20 in a side view is inclined in a direction toward the front side as it goes toward the rear end side. The back side of the neck portion 20 in the side view is inclined in the direction toward the back side as it goes toward the rear end side. The neck portion 20 is inclined in a direction in which the distance from the center in the width direction increases toward the rear end side in the front view.

The boundary between the neck portion 20 and the grip portion 30 in the present embodiment is a position at which the increase in distance from the center in the width direction ends as the distance increases toward the rear end side in the front view. Here, the width from the neck portion 20 toward the grip portion 30 is enlarged in both front and side views by an arc-shaped contour, and coincides with the position in the longitudinal direction after the position of the curvature center of the arc is changed. More specifically, the boundary between the neck portion 20 and the grip portion 30 coincides with the position in the longitudinal direction after the curvature center changes to the rear end side outside the arc-shaped contour in the front view shown in fig. 1. In addition, the boundary between the neck portion 20 and the grip portion 30 coincides with the position in the longitudinal direction after the curvature center is changed to the rear end side outside the arc-shaped contour in the side view shown in fig. 2.

[ grip part 30]

The grip 30 is disposed along the longitudinal direction. As shown in fig. 1, the length of the grip portion 30 in the width direction gradually decreases from the boundary with the neck portion 20 toward the rear end side, and then extends at a substantially constant length. As shown in fig. 2, the length of the grip portion 30 in the thickness direction gradually narrows from the boundary with the neck portion 20 toward the rear end side, and then extends at a substantially constant length.

The length of the grip portion 30 in the width direction is the same as the position in the longitudinal direction where the length becomes substantially constant as the length gradually narrows from the boundary with the neck portion 20 toward the rear end side, and the length of the grip portion 30 in the thickness direction is the same as the position in the longitudinal direction where the length becomes substantially constant as the length gradually narrows from the boundary with the neck portion 20 toward the rear end side.

The position of the distal end of the deformable portion 70 in the axial direction in the grip portion 30 of the present embodiment is the boundary between the neck portion 20 and the grip portion 30. The position of the rear end side end portion in the longitudinal direction of the deformable portion 70 is a position that becomes substantially constant in length as gradually narrowing from the boundary with the neck portion 20 toward the rear end side, and is a boundary between the soft portion 70E and the hard portion 30H, which will be described later.

The grip portion 30 has a soft portion 31E at the center in the width direction on the front side, on the rear end side of the rear end side end portion of the deformation portion 70. The soft portion 31E constitutes a part of the soft portion E. The soft portion 31E extends in the longitudinal direction with a substantially constant width in the front view. The side edge of the soft portion 31E is formed at a substantially constant distance from the side edge on the outer side in the width direction of the grip portion 30 in the front view.

The grip portion 30 includes a hard portion 70H provided on the deformable portion 70 and a hard portion 30H provided on the rear end side of the deformable portion 70. The

hard portions

30H, 70H constitute a part of the hard portion H. The hard portion 30H has a recess 31H in which the soft portion 31E is embedded on the front surface side. The recess 31H extends in the longitudinal direction from the boundary with the deformation portion 70 toward the rear end side by a substantially constant length in front view. The soft portion 31E embedded in the recess 31H is substantially flush with the hard portion 30H exposed on the front side.

The grip portion 30 has a soft portion 32E (see fig. 1 and 2) at the center in the width direction on the back surface side. The soft portion 32E constitutes a part of the soft portion E. The soft portion 32E has an outline substantially the same as the outline of the soft portion 31E in the front view. That is, the soft portion 32E extends in the longitudinal direction with a substantially constant width in the front view. The side edge of the soft portion 32E is formed at a substantially constant distance from the side edge on the outer side in the width direction of the grip portion 30 in a rear view.

The hard portion 30H has a recess 32H (see fig. 2) in which the soft portion 32E is embedded on the back surface side. The recess 32H extends in the longitudinal direction with a substantially constant width in front view. The soft portion 32E is substantially flush with the hard portion 30H exposed on the back surface side.

Since the soft portion 31E is provided on the front side of the grip portion 30 and the soft portion 32E is provided on the rear side, the grip performance when gripping the grip portion 30 is improved.

[ deformation part 70]

Fig. 4 is a cross-sectional view of the deformation portion 70 perpendicular to the longitudinal direction, and is a cross-sectional view taken along line a-a in fig. 1.

The deformation portion 70 is deformed by an external force in a first direction perpendicular to the flocked surface 11. The deformable portion 70 has a hard portion 70H and a soft portion 70E. In the present embodiment, the periphery of the hard portion 70H is covered with the soft portion 70E. The maximum length of the deformation portion 70 in the longitudinal direction is preferably 15mm to 70 mm. By setting the maximum length of the deformable portion 70 in the longitudinal direction to 15mm or more, the user can sufficiently feel the deformation of the deformable portion 70 when gripping the grip portion 30. Further, by setting the maximum length of the deformable portion 70 in the longitudinal direction to 70mm or less, it is possible to suppress the deformable portion 70 from being easily bent excessively. In addition, the deformation region of the gripped portion is limited, and the reduction in operability is suppressed. The upper limit of the maximum length of the deformable portion 70 in the longitudinal direction is preferably 70mm or less, and more preferably 55mm or less.

The width of the deformable portion 70 is preferably 8mm to 15mm from the viewpoint of ensuring sufficient deformation and operability during gripping.

The thickness of the deformable portion 70 is preferably 6mm to 12mm from the viewpoint of ensuring sufficient deformation and operability during gripping.

As shown in fig. 4, the hard portion 70H is formed in a rectangular shape extending in the width direction with a larger width than thickness. When the width of the hard portion 70H is W and the thickness of the hard portion 70H is T, the hard portion 70H satisfies the following expression (1) in the entire longitudinal direction. The width W and the thickness T in the following formula (1) do not include regions of curved surfaces 73H to 76H described later.

T/W＜1 (1)

By making the width W and the thickness T of the hard portion 70H satisfy the formula (1) in the entire longitudinal direction, the hard portion 70H has a bending action that is easy to bend in the thickness direction and difficult to bend in the width direction. In formula (1), T/W < 0.35 is preferred, and T/W < 0.20 is more preferred.

The center position in the thickness direction of the hard portion 70H is disposed on the rear side of the center position in the thickness direction of the deformable portion 70 at the position of the apex in the width direction of the outer diameter contour (outer contour) of the soft portion 70E. That is, the hard portion 70H is disposed eccentrically toward the rear surface side in the thickness direction. This makes it possible to stably maintain the bending operation in which the hard portion 70H is easily bent in the thickness direction and is hardly bent in the width direction even when the deformation portion 70 is deformed.

The thickness (minimum thickness) of the hard portion 70H is preferably 0.5mm or more and 2.0mm or less, and more preferably 0.5mm or more and 2.0mm or less over the entire hard portion 70H (excluding the regions of the curved surfaces 73H to 76H) in the long axis. When the thickness of the hard portion 70H is less than 0.5mm, the head 10 is easily deformed when an external force is applied to the back surface side, and therefore, a plane stress state in which an internal stress is hardly generated is obtained, and durability can be secured, but the deformation of the deforming portion 70 becomes large, and there is a possibility that workability during brushing is deteriorated. When the thickness of the hard portion 70H exceeds 2.0mm, the head 10 is less likely to be deformed by an external force applied to the back surface side, and therefore, a planar deformation state in which internal stress is generated may be obtained, and the durability may be reduced. Therefore, by setting the thickness of the hard portion 70H to 0.5mm or more and 2.0mm or less, the durability of the deformable portion 70 can be ensured while maintaining the operability during brushing.

Fig. 5 is a partially enlarged front view of the hard portion 70H in the hard portion H. Fig. 6 is a side view of fig. 5.

As shown in fig. 5, the hard portion 70H is connected to the hard portion 20H of the neck portion 20 at the distal end side and connected to the hard portion 30H of the grip portion 30 at the rear end side. The hard portion 20H connected to the hard portion 70H constitutes a rigid first region a1 having greater bending strength in the width, thickness, and thickness directions than the hard portion 70H. The hard portion 30H connected to the hard portion 70H constitutes a rigid second region a2 having greater bending strength in the width, thickness, and thickness directions than the hard portion 70H.

At least a part of a cross section of the grip 30 perpendicular to the longitudinal direction is formed of a hard resin at least from the tip of the grip 30 to the second region a2 in the longitudinal direction. In each of the first region a1 and the second region a2 of the present embodiment, the proportion of the hard resin is greater than the proportion of the soft resin in the cross section perpendicular to the longitudinal direction. For example, the first region a1 in the present embodiment has a hard resin content of 100%. The hard resin in the second region a2 accounts for about 80% or more.

The width of the hard portion 70H gradually narrows from the boundary with the hard portion 20H of the neck portion 20 toward the rear end side in the front view, and then extends at a substantially constant length. Therefore, the width of the hard portion 70H is smaller on the rear end side than on the front end side.

The width of the distal end of the hard portion 70H is formed smaller than the width of the rear end of the hard portion 20H of the neck portion 20, depending on the thickness of the soft portion 70E outside the hard portion 70H in the width direction. Similarly, the width of the rear end side end portion of the hard portion 70H is formed smaller than the width of the front end side end portion of the hard portion 30H in accordance with the thickness of the soft portion 70E on the outer side in the width direction than the hard portion 70H.

As shown in fig. 6, the front-side distal end side of the hard portion 70H is connected to the hard portion 20H (first region a1) by an arc-shaped curved surface 73H in side view. The arc center of the curved surface 73H is located on the front side of the hard portion 70H in side view. The front end side of the rear surface side of the hard portion 70H is connected to the hard portion 20H (first region a1) by an arc-shaped curved surface 75H in side view. The arc center of the curved surface 75H is located closer to the backrest surface side than the hard portion 70H in side view. The curved surface 73H and the curved surface 75H form first thickened portions, respectively, which are gradually thickened and increased in thickness as the hard portion 70H moves toward the tip side, and are connected to the hard portion 20H.

The rear end side of the front surface side of the hard portion 70H is connected to the hard portion 30H (second region a2) by an arc-shaped curved surface 74H in side view. The arc center of the curved surface 74H is located on the front side of the hard portion 70H in side view. The rear end side of the rear surface side of the hard portion 70H is connected to the hard portion 30H (second region a2) by an arc-shaped curved surface 76H in side view. The arc center of the curved surface 76H is located closer to the backrest surface side than the hard portion 70H in side view. The

curved surfaces

74H and 76H form second thickened portions, respectively, which are gradually thickened and increased in thickness as the hard portion 70H moves toward the rear end side, and are connected to the hard portion 30H. The maximum thickness of the second thickened portion is formed smaller than the maximum thickness of the first thickened portion on the front surface side and the back surface side. That is, the maximum thickness of the curved surface 74H is formed smaller than the maximum thickness of the curved surface 73H on the front surface side, and the maximum thickness of the curved surface 76H is formed smaller than the maximum thickness of the curved surface 75H on the rear surface side. The maximum thickness of the rear end side end of the hard portion 70 including both the front and rear second thickened portions is formed smaller than the maximum thickness of the front end side end of the hard portion 70 including both the front and rear first thickened portions. Between the first thickened portion and the second thickened portion (between the

curved surfaces

73H, 75H and the

curved surfaces

74H, 76H) in the long axis direction is a constant thickness portion.

When the curved surfaces 73H to 76H are not present, stress may be concentrated on the boundary between the front end side of the hard portion 70H and the hard portion 20H and the boundary between the rear end side of the hard portion 70H and the hard portion 30H. In contrast, the presence of the curved surfaces 73H to 76H relieves the concentrated stress. Moreover, the curved surfaces 73H to 76H allow both the front end side and the rear end side of the deforming portion 70 to be deformed with flexibility.

The hard portion 70H is embedded in the soft portion 70E. Since the hard portion 70H is embedded in the soft portion 70E, the stress applied to the hard portion 70H can be relaxed in terms of strength. Further, the elastic operation of the deformation portion 70 can be controlled in terms of the degree of deflection of the toothbrush 1 with respect to the load.

As a material of the hard portion H, a resin having a flexural modulus of elasticity (JIS7171) of 1500MPa or more and 3500MPa or less, for example, a polyacetal resin (POM) is exemplified. The flexural modulus of the hard portion H is more preferably 2000MPa or more and 3500MPa or less. By using a raw material having a high elastic modulus (for example, POM), the shape can be thinned or thinned.

As shown in fig. 4, the soft portion 70E has a cross section having a substantially hexagonal outline in which the hard portion 70H is embedded. Two of the six vertexes arranged midway in the thickness direction are arranged on the center back surface side in the thickness direction with respect to the deformable portion 70 (soft portion 70E).

The occupancy rate of the cross-sectional area of the hard portion 70H with respect to the cross-sectional area of the deformed portion 70 in the cross section orthogonal to the longitudinal direction is 35% or less, preferably 25% or less, in the entire longitudinal direction. The cross-sectional area of the hard portion 70H is the cross-sectional area of the above-described set thickness portion. By setting the occupancy of the cross-sectional area of the hard portion 70H to 35% or less in the entire longitudinal direction, the bending strength of the deformed portion 70 toward the back surface side can be reduced.

As a material of the soft portion E, a material having a shore a hardness of 90 or less is preferable, and a material having a shore a hardness of 50 to 80 is more preferable, from the viewpoint of maintaining the recommended value of the brushing load. Examples of the soft resin include elastomers (e.g., olefin elastomers, styrene elastomers, polyester elastomers, polyurethane thermoplastic elastomers, etc.), and silicones. A styrene-based elastomer is preferable from the viewpoint of excellent miscibility with the polyacetal resin.

In the toothbrush 1 described above, when an external force is applied to the head 10 toward the back side while the grip portion 30 is gripped, the first region a1 on the front end side and the second region a2 on the rear end side of the deformable portion 70 are not deformed because they have a higher bending strength and are stiffer than the rigid portions 70H, and the deformable portion 70 disposed between the first region a1 and the second region a2 is deformed.

When the deformation portion 70 is deformed, the width of the rear end side is smaller than the width of the front end side, and the maximum thickness of the second thickened portion on the rear end side formed by the

curved surfaces

74H and 76H is smaller than the maximum thickness of the first thickened portion on the front end side formed by the

curved surfaces

73H and 75H, and the bending strength is small, so that the deformation starts from the rear end side first. At this time, since the rigid second region a2 exists, propagation of stress to the grip portion 30 on the rear end side of the deformable portion 70 is suppressed.

When the bending operation is performed from the bending on the rear end side, the front end side of the deformation portion 70 starts to bend, but since the width on the front end side is larger than the width on the rear end side, the maximum thickness of the first thickened portion on the front end side formed by the

curved surfaces

73H and 75H is larger than the maximum thickness of the second thickened portion on the rear end side formed by the

curved surfaces

74H and 76H, and the bending strength is large, so that the stress concentration is relaxed compared with the rear end side, and the excessive bending of the deformation portion 70 is suppressed. Further, since the rigid first region a1 is present, propagation of stress to the neck portion 20 on the tip side of the deformable portion 70 is further suppressed.

That is, the rear end side of the deformable portion 70 promotes clear bending, and the front end side of the deformable portion 70 suppresses excessive bending. Thus, even if the deformable portion is bent, the grip portion 30 on the rear end side of the deformable portion 70 is not bent, and therefore, the effect of not affecting the operability of the grip can be obtained. Further, the deformation portion tip portion is also suppressed from being excessively bent, and since the cushioning effect stress is hard to concentrate, even if the thickness of the head portion is reduced to 2.0 to 4.0mm, and the minimum width and thickness of the neck portion are reduced to 3.0 to 4.5mm or less, for example, the folding strength at the boundary between the neck portion and the deformation portion can be ensured.

Further, since the deformable portion 70 is designed as described above and the front end and the rear end are sandwiched by the rigid regions (the first region a1 and the second region a2), the deformable region (the deformable portion 70) is clearly divided into the non-deformable region (the neck portion 20 and the grip portion 30 other than the deformable portion 70). This makes it possible to design the deformed region so as to improve flexibility without considering the strength, and to strongly reflect the contrast in strength when compared with the non-deformed region.

In order to exhibit the function of the distal end side of the deformed portion 70, the width of the distal end side of the hard portion 70H is 10.5mm or less, preferably 9.0mm or less, the radius of the

curved surfaces

73H, 75H forming the first thickened portion of the distal end side of the hard portion 70H is 15mm or less, preferably 13mm or less, and the length of the

curved surfaces

73H, 75H in the longitudinal direction (the length in the longitudinal direction from the connection portion of the

curved surfaces

73H, 75H with the hard portion 20H of the neck portion 20 to the thickness of the hard portion 70H being constant) is preferably less than 35% of the length of the deformed portion 70 in the longitudinal direction.

In order to exhibit the function of the rear end side of the deformed portion 70, the width of the rear end side of the hard portion 70H is 9.0mm or less, preferably 7.0mm or less, the radius of the

curved surfaces

74H and 76H forming the second thickened portion of the rear end side of the hard portion 70H is 10mm or less, preferably 8mm or less, and the length of the

curved surfaces

74H and 76H in the longitudinal direction (the length of the

curved surfaces

74H and 76H in the longitudinal direction from the connection portion with the hard portion 30H to the hard portion 70H where the thickness is constant) is preferably less than 35% of the length of the deformed portion 70 in the longitudinal direction.

The ratio of the width of the deformed portion 70 at the rear end side to the width at the front end side is preferably 0.40 to 0.95, and more preferably 0.50 to 0.80.

Thus, in the toothbrush 1 of the present embodiment, it is possible to provide a gentle and comfortable operability to the teeth and the gums without damaging the gums, and to sufficiently reduce an excessive brushing pressure.

[ second embodiment ]

Next, a second embodiment of the toothbrush 1 will be described with reference to (a) to (C) of fig. 7.

Fig. 7 (a) is a front view including a cross-sectional view obtained by partially cutting the toothbrush 1 according to the second embodiment with a plane including the center in the thickness direction, fig. 7 (B) is a cross-sectional view obtained by partially cutting the toothbrush 1 with a plane including the center in the width direction, and fig. 7 (C) is a rear view including a cross-sectional view obtained by partially cutting a part of the toothbrush 1 with a plane including the center in the thickness direction. In fig. 7 (a) and (C), the front view (or the rear view) is a cross-sectional view taken along a plane including the center in the thickness direction from a position L1 distant from a position L0 of the boundary between the neck portion 20 and the grip portion 30 by a predetermined distance toward the rear end side to the rear end side. In these drawings, the same components as those of the toothbrush 1 of the first embodiment shown in fig. 1 to 6 are denoted by the same reference numerals, and the description thereof is omitted.

The length of the deformed portion 70 in the longitudinal direction of the toothbrush 1 of the second embodiment is longer than that of the toothbrush 1 of the first embodiment. The position L5 of the rear end side end of the deforming portion 70 is located on the rear end side of the center of the grip portion 30 in the axial direction. The length 70L in the longitudinal direction of the deformation portion 70 is longer than half the length in the longitudinal direction of the grip portion 30.

As shown in fig. 7 (a), the width of the hard portion 70H gradually narrows from the position L1 toward the rear end side, and then extends from the position L2 to the position L4 with a substantially constant width. The width of the hard portion 70H gradually increases from the position L4 to the position L5 toward the rear end side, and then extends to the rear end side end portion with a substantially constant width.

The width of the hard portion 70H gradually decreases from the position L1 to the position L2 toward the rear end side with a locus in the shape of an arc having the center located on the outer side in the width direction in plan view. The width of the hard portion 70H gradually increases from the position L4 to the position L5 toward the rear end side along an arc-shaped locus whose center is located outward in the width direction in a plan view.

As shown in fig. 7 (B), the thickness of the hard portion 70H gradually decreases from the position L1 to the position L2 through the

curved surfaces

73H and 75H, and then extends from the position 2 to the position L3 as a thick portion having a substantially constant thickness. The thickness of the hard portion 70H gradually increases from the position L3 to the position L5 through the

curved surfaces

74H and 76H, and then extends to the rear end side end portion with a substantially constant thickness.

The length 77L of the thickness-fixing portion in the longitudinal direction is preferably 10% to 90%, more preferably 20% to 70%, of the length of the grip portion 30 in the longitudinal direction. When the length 77L of the thickness portion in the longitudinal direction is less than 10% of the length of the grip portion 30 in the longitudinal direction, there is a possibility that the head portion 10 is not deformed flexibly when an excessive brushing pressure is applied. When the length 77L of the thickness portion in the long axis direction exceeds 90% of the length of the grip portion 30 in the long axis direction, the deformation increases when an excessive brushing pressure is applied to the head 10, and there is a possibility that the operability during brushing is lowered. By setting the length 77L of the thickness portion in the long axis direction to 10% or more and 90% or less of the length of the grip portion 30 in the long axis direction, it is possible to provide gentle and comfortable operability to the teeth and the gum without damaging the gum, and sufficiently reduce excessive brushing pressure. Further, for example, when the grip portion 30 is gripped by a palm grip method, the entire grip portion 30 can be appropriately matched to the shape of the hand.

In the case of the toothbrush 1 according to the second embodiment, the length in the longitudinal direction of the position L4 to the position L5 and the length in the longitudinal direction of the position L3 to the position L5 are preferably longer than the length in the longitudinal direction of the position L1 to the position L2.

This can suppress the grip portion 30 from being excessively bent on the tail side even if the deformable portion 70 is of a long size. For the same reason, the length in the longitudinal direction of the position L3 to the position L5 is preferably longer than the length in the longitudinal direction of the position L4 to the position L5.

[ examples ]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples, and can be implemented by appropriately changing the examples without departing from the spirit and scope thereof.

Examples 1 to 6 and comparative examples 1 to 4

Samples of examples 1 to 6 and comparative examples 1 to 4 were prepared according to the specifications shown in the following [ Table 1 ].

Examples 1 to 5 and comparative examples 1 to 2 each use the toothbrush shown in the first embodiment as a sample. Example 6 and comparative example 3 were samples of the toothbrush according to the second embodiment. Comparative example 4 a toothbrush having "Clinica advantaged 3-line common bristles" manufactured by lion king corporation having no deformation portion was used as a sample.

[ evaluation method ]

Examples 1 to 6 and comparative examples 1 to 4 were evaluated for impact strength, fatigue strength and workability, respectively.

The impact strength was measured by fixing a 60mm portion from the rear end of the grip portion and applying a load of 2kg to the head from a height of 60cm (number of samples; n: 5).

As a result of the impact strength, the case where the head portion was not broken and no crack was generated was marked as "O" (OK), the case where the head portion was not broken and the crack was 0.2mm or less was marked as "Delta" (OK), and the case where the head portion was broken was marked as "X" (NG).

The fatigue strength was measured by fixing a 60mm portion from the rear end of the grip portion and repeatedly applying a 50mm displacement (number of samples; n: 5) to the head at 240 rpm.

When the above-described load was repeatedly applied 100 ten thousand times, the case where the crack was not generated was marked by "o" (OK), the case where the crack was not generated but 0.2mm or less was marked by "Δ" (OK), and the case where the crack was generated was marked by "x" (NG).

For evaluation of usability, each sample was used 5 days later and investigated. Panelists performed with 6 panelists. The examination items were two items, namely "the feeling that the grip deformed to reduce the brushing pressure and enabled stable brushing" and "the feeling that the grip engaged with the hand during brushing", and the evaluation was performed in 7 stages and the average score was used for the evaluation. The mean of the scores is the number of digits to the first place of the decimal point rounded off.

(1) The grip part is deformed to reduce the brushing pressure

[ score ]7 points: strong sensation, 6 points: very perceptible, 5 points: slightly felt, 4 points: sensation neither strong nor weak, 3 points: less perceptible, 2 points: little sensation, 1 point: evaluation was carried out in 7 stages with no sensation at all.

[ evaluation ]. circleincircle + (excellent): more than 6.0 min ∈ (very good): score 5.5 or more, o (good): above 4.5 points, Δ (tolerance): 4.0 or more, x (poor): more than 1 minute to less than 4.0 minutes.

(2) Feeling of coincidence of the grip part in brushing

[ score ]7 points: strong sensation, 6 points: very perceptible, 5 points: slightly felt, 4 points: sensation neither strong nor weak, 3 points: less sensation, 2 points: hardly any sense, 1 point: evaluation was carried out in 7 stages with no sensation at all.

[ evaluation ]. smallcircle (good): above 4.5 points, Δ (tolerance): 4.0 or more, x (poor): more than 1 minute to less than 4.0 minutes.

[ TABLE 1]

As shown in Table 1, the samples of examples 1 to 6 having deformed portions 70 and hard portions 70H each having a thickness T and a width W satisfying a relationship of T/W < 1 and having a cross section of the hard portion 70H in a cross section orthogonal to the longitudinal direction occupying a ratio of 35% or less of the cross section of the deformed portion 70 both satisfy predetermined values of impact strength and fatigue strength. Further, regarding usability, in the samples of the examples, good evaluations were made for "the feeling that the grip portion was deformed to reduce the brushing pressure and to brush stably" and "the feeling that the grip portion was fitted to the hand during brushing".

On the other hand, in the samples of comparative examples 1, 3, and 4 in which the relation of T/W < 1 is not satisfied even with the deformed portion, the brush pressure reduction effect is insufficient because the sample is deflected in the side surface direction, and a good evaluation was not obtained for "the grip portion is deformed to reduce the brush pressure and to stably brush the brush. In the sample of comparative example 2 in which the occupancy rate of the cross-sectional area of the hard portion 70H with respect to the cross-sectional area of the deformed portion 70 exceeded 35%, the soft portion did not absorb the load and the stress was directly transmitted to the hard portion, and therefore the head portion broke due to both the impact strength and the fatigue strength.

While preferred embodiments of the present invention have been described above with reference to the drawings, it is needless to say that the present invention is not limited to the above examples. The shapes, combinations, and the like of the respective components shown in the above examples are examples, and various modifications can be made based on design requirements and the like without departing from the scope of the present invention.

For example, in the above embodiment, the soft portion 70E is exemplified as a structure covering the periphery of the hard portion 70H over the entire circumference, but the present invention is not limited to this structure, and a structure in which a part of the hard portion 70H is exposed without being covered may be employed.

In the above embodiment, the thickened portions are provided on both the front surface side and the back surface side of the hard portion 70H, but the thickened portions may be provided only on one of the front surface side and the back surface side.

[ industrial applicability ]

The present invention can be applied to a toothbrush.

Description of the reference symbols

1 … toothbrush; 2 … handle body; 10 … a head; 11 … flocking surface; 20 … neck; 30 … a grip; a 70 … deformation; a1 … first region; a2 … second area; E. 31E, 32E, 70E … soft portions; H. a 70H … hard portion; 73H, 75H … curved surface (first thickening portion); 74H, 76H … are curved surfaces (second thickened portions).

Claims

1. A toothbrush, comprising: a head portion provided on a distal end side in a longitudinal direction and having a hair-setting surface; a grip portion disposed on a rear end side of the head portion; and a neck portion disposed between the bristle surface and the holding portion,

at least a part of the head and the neck is formed of a hard resin,

the toothbrush has:

a deformation portion disposed on the holding portion and deformed by an external force in a first direction orthogonal to the flocked surface;

a first region which is disposed on the distal end side of the deformation portion and is not deformed by an external force in the first direction; and

a second region which is disposed on the rear end side of the deformation portion and is not deformed by an external force in the first direction,

wherein the grip portion is formed of the hard resin at least in a part of a cross section orthogonal to the longitudinal direction from at least a tip of the grip portion to the second region in the longitudinal direction,

the deformation portion has:

a flat plate-shaped hard portion formed of the hard resin; and

a soft portion formed of a soft resin and covering at least a part of the hard portion,

an occupancy rate of a cross-sectional area of the hard portion with respect to a cross-sectional area of the deformed portion in a cross-section orthogonal to the longitudinal direction is 35% or less over the longitudinal direction,

when T is a thickness of the hard portion in the first direction and W is a width of the hard portion in a second direction perpendicular to the longitudinal direction and the first direction, a relation of T/W < 1 is satisfied over the entire longitudinal direction.

2. The toothbrush of claim 1,

the hard portion has: a first thickened portion which is connected to the first region so that a thickness in the first direction gradually increases toward a front end side in the longitudinal direction; and a second thickened portion which is connected to the second region with a thickness in the first direction gradually increasing toward a rear end side in the longitudinal direction.

3. The toothbrush of claim 2, wherein,

the maximum thickness of the second thickened portion is less than the maximum thickness of the first thickened portion.

4. The toothbrush according to any one of claims 1 to 3,

the width of the rear end side end portion of the hard portion connected to the second region is smaller than the width of the front end side end portion connected to the first region.

5. The toothbrush according to any one of claims 1 to 4,

the hard portion has a minimum thickness in the first direction of 0.5mm to 2.0 mm.

6. The toothbrush according to any one of claims 1 to 5,

the length of the deformation portion in the long axis direction is 15mm or more.

7. The toothbrush according to any one of claims 1 to 6,

the maximum thickness of the head portion in the first direction is 2.0mm or more and 4.0mm or less.

8. The toothbrush according to any one of claims 1 to 7,

the minimum thickness of the neck portion in the first direction and the minimum width of the neck portion in the second direction are 3.0mm to 4.5 mm.