CN114025643B

CN114025643B - Toothbrush with tooth brush

Info

Publication number: CN114025643B
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: 2024-06-04
Anticipated expiration: 2040-06-23
Also published as: JP7466539B2; KR20220029539A; TW202100062A; JPWO2020262346A1; CN114025643A; WO2020262346A1

Abstract

The invention aims to provide a toothbrush capable of sufficiently reducing excessive brushing pressure. At least a part of the head and neck is formed of a hard resin, and includes: a deformation part (70) which is configured at 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 the first direction; and a second region disposed on a rear end side of the deformation portion, the second region being free from deformation by an external force in the first direction, the grip portion being formed of a hard resin at least from a distal end of the grip portion to the second region in the longitudinal direction, at least a part of a cross section orthogonal to the longitudinal direction, the deformation portion having: a flat plate-shaped hard part (70H) formed by 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 of the cross-sectional area of the hard portion to the cross-sectional area of the deformed portion is 35% or less in the entire long axis direction, and the relationship of T/W < 1 is satisfied in the entire long axis direction when the thickness of the hard portion in the first direction is T and the width of the hard portion in the second direction is W.

Description

Toothbrush with tooth brush

Technical Field

The present invention relates to toothbrushes.

The present application claims priority based on 2019, 6, 28 in japanese patent application publication No. 2019-121415 of the japanese application, and the contents thereof 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 the elderly is increasing. Root caries is caries of dentin exposed by gingival atrophy, and the caries progresses rapidly because the composition ratio of organic components is high in dentin as compared with enamel. One of the causes of the above gum atrophy is excessive brushing in which brushing is performed with a brushing pressure that is higher than an appropriate value.

Conventionally, as a toothbrush for reducing excessive brushing pressure, for example, a toothbrush disclosed in patent document 1 is disclosed. In the toothbrush described in patent document 1, when the toothbrush is held by a palm grip method and brushed, a portion of the handle portion which is held by the thumb and the index finger and which is formed of a thermoplastic resin is formed in a U shape opening toward the bristle surface side, and the periphery of the portion formed of the thermoplastic resin is covered with a soft resin such as an elastomer material.

Regarding the toothbrush of the above-described structure in patent document 1, the following is described: by applying the load of the head not only to the neck but also to the portion of the handle portion, the gum is not damaged, a gentle and comfortable operability is imparted to the teeth and gum, and the excessive brushing pressure is reduced.

Prior art literature

Patent literature

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

Disclosure of Invention

Problems to be solved by the invention

However, in the conventional toothbrush as described above, the portion to which the elastic force is applied is localized in consideration of the filling property of the soft resin while maintaining the mechanical strength, and it cannot be said that the excessive reduction in 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 the 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 part which is arranged at the front end side in the long axis direction and is provided with a hair planting 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 comprising: a deformation portion which is arranged on the holding portion and deforms due to an 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 the first direction; and a second region disposed on the rear end side of the deformation portion so as not to be deformed by an external force in the first direction, wherein the grip portion is formed of the hard resin at least from a distal end of the grip portion to the second region in the longitudinal direction, and at least a part of a cross section orthogonal to the longitudinal direction is formed of the hard resin, 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 with respect to a cross-sectional area of the deformed portion in a cross-section orthogonal to the longitudinal direction is 35% or less in the entire longitudinal direction, and a relationship of T/W <1 is satisfied in 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 the second direction orthogonal to the longitudinal direction and the first direction is W.

In the toothbrush according to the aspect of the present invention, the hard portion includes: a first thickening portion that is connected to the first region so as to gradually increase in thickness in the first direction toward the distal end side in the longitudinal direction; and a second thickening portion that is connected to the second region so as to gradually increase in thickness in the first direction toward the rear end side in the longitudinal direction.

In the toothbrush according to the aspect of the present invention, the second thickening portion has a maximum thickness smaller than that of the first thickening portion.

In the toothbrush according to the aspect of the present invention, 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.

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

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

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

In the toothbrush according to the 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 or more and 4.5mm or less.

Effects of the invention

The present invention can provide a toothbrush which can provide soft and comfortable operability to teeth and gums without damaging the 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 cross-sectional view of the toothbrush 1 cut through a plane including the center in the width direction.

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

Fig. 4 is a cross-sectional view taken along line A-A in fig. 1.

Fig. 5 is a front view partially enlarged around 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 the center in the thickness direction, (B) is a sectional view partially cut with a plane including the center in the width direction, and (C) is a rear view including a sectional view partially cut with a plane including the center in the thickness direction.

Detailed Description

Hereinafter, an embodiment of the toothbrush according to 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 limited to the present invention, and may be arbitrarily modified within the scope of the technical idea of the present invention. In the following drawings, the scale, the number, and the like in each structure are different from those in actual structures for easy understanding of each structure. In the following description, a direction perpendicular to the bristle surface in a side view is referred to as a thickness direction, a bristle surface side in the thickness direction is referred to as a front surface side, and a side opposite to the bristle surface is referred to as a 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 through a plane including the center in the width direction (up-down direction in fig. 1). Fig. 3 is a front view of a hard portion H constituting the toothbrush 1.

The toothbrush 1 of the present embodiment includes: a head 10 disposed on a distal end side (hereinafter, simply referred to as a distal end side) in the longitudinal direction, and into which tufts (not shown) of bristles are implanted; a neck portion 20 extending toward the rear end side (hereinafter, simply referred to as the rear end side) of the head portion 10 in the longitudinal direction; and a grip portion 30 that is provided to extend to the rear end side of the neck portion 20 and has a deformed portion 70 (hereinafter, the head portion 10, the neck portion 20, and the grip portion 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 forms at least a part of the head 10, the neck 20, the grip 30, and the deformed portion 70. The soft portions E constitute a part of the grip portion 30 and the deformed portion 70, respectively. More specifically, the head 10 and the neck 20 of the present embodiment are each formed of a hard resin, but may be partially formed 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 deformation portion 70 of the present embodiment is formed of both hard resin and soft resin (described in detail later).

[ Head 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). In the following, a direction perpendicular to the thickness direction and the long axis direction is referred to as a width direction (or a side direction as appropriate). A plurality of implantation holes 12 are formed in the implantation surface 11. Tufts (not shown) each having bristles are implanted into the implantation holes 12.

The width of the head 10, that is, the length in the width direction (hereinafter, simply referred to as the width) parallel to the hair-planting surface 11 on the front side and orthogonal to the longitudinal direction is not particularly limited, and is preferably 7mm to 13 mm. If the lower limit value is not less than the upper limit value, the area where the hair bundle is planted can be sufficiently ensured, and if the upper 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 the length) is not particularly limited, and is preferably, for example, 10mm to 33 mm. If the length of the head 10 is equal to or greater than the lower limit, the area where the hair bundle is implanted can be sufficiently ensured, and if it is equal to or less than the upper limit, the operability in the oral cavity can be further improved. The boundary between the neck 20 and the head 10 in the longitudinal direction of the present embodiment is a position where the width of the neck 20 is the minimum value in the direction from the neck 20 toward the head 10. When the region where the width of the neck 20 is the smallest is present in a certain length (when the position where the width of the neck 20 is the smallest is not one), the boundary between the neck 20 and the head 10 in the longitudinal direction is the position on the head tip side where the width of the neck 20 is the smallest.

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, the accessibility to the deep part of the molar teeth can be improved, and the operability in the oral cavity can be further improved.

The hair bundle is formed by bundling a plurality of bristles. The length (bristle length) from the bristle surface 11 to the distal end of the tuft can be determined in consideration of the waist and the like required for the tuft, and is, for example, 6 to 13mm. All tufts may have the same bristle length or may be different from each other.

The thickness of the tufts (tuft diameter) can be determined by taking into consideration the waist and the like required for the tufts, and is, for example, 1 to 3mm. All the tufts may have the same tuft diameter or may be different from each other.

Examples of the bristles constituting the tuft include bristles (tapered bristles) having a diameter gradually decreasing toward the bristle tips and tapered bristle tips, bristles (straight bristles) having a diameter substantially equal from the bristle planting surface 11 toward the bristle tips, and the like. The straight bristles include bristles having bristle tips in a plane substantially parallel to the bristle surface 11 and bristles having bristle tips rounded in a hemispherical shape.

Examples of the material of the bristles include polyamides such as 6-12 nylon (6-12 NY) and 6-10 nylon (6-10 NY), and elastomeric resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), polyesters such as 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 can be mentioned polyester bristles having a multi-layered core structure including a core portion and at least 1 or more sheath portions provided outside the core portion.

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

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

[ Neck 20]

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

As an example, the width of neck 20 is formed to gradually increase from the position at which the width becomes the minimum value toward the rear end side. The neck portion 20 in the present embodiment is formed so as to become gradually larger from a position where the width is at a minimum toward the rear end side. The thickness of the neck portion 20 is formed to gradually increase from the smallest position toward the rear end side.

The width and thickness of neck 20 at the minimum position are preferably 3.0mm or more and 4.5mm or less. If the width and thickness of the neck 20 at the minimum position are equal to or greater than the above-described lower limit, the strength of the neck 20 can be further improved, and if the width and thickness are equal to or less than the above-described upper limit, the lips can be easily closed, the accessibility 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 so as to gradually increase from the position at which the minimum value is reached toward the rear end side can be appropriately determined in consideration of the material and the like.

The front side of neck 20 in a side view is inclined in a direction toward the front side as it is toward the rear end side. The rear side of neck 20 in a side view is inclined in a direction toward the rear side as it is toward the rear end side. The neck portion 20 is inclined in a direction in which the distance from the widthwise center becomes larger as it goes 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 widthwise center ends with the direction toward the rear end in the front view. Here, the width of the neck portion 20 toward the grip portion 30 is widened in a circular arc-shaped contour in both front view and side view, and the width matches the position of the center of curvature of the circular arc in the long axis direction after the position change. More specifically, the boundary between neck 20 and grip 30 coincides with the position of the center of curvature in the long axis direction after the change from the outer side to the rear end side of the arcuate contour in the front view shown in fig. 1. In the side view shown in fig. 2, the boundary between the neck portion 20 and the grip portion 30 coincides with the position of the center of curvature in the long axis direction after the outer side of the arcuate contour changes to the rear end side.

[ Grip portion 30]

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

The length in the width direction of the grip portion 30 becomes substantially constant in length from the boundary with the neck portion 20 toward the rear end side, and the length in the thickness direction of the grip portion 30 becomes substantially constant in length from the boundary with the neck portion 20 toward the rear end side.

The position of the distal end side end portion of the deformation portion 70 in the longitudinal 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 portion of the deformation portion 70 in the longitudinal direction is a position that becomes substantially constant in length as it gradually narrows from the boundary with the neck portion 20 toward the rear end, and is a boundary between the soft portion 70E and the hard portion 30H described later.

The grip portion 30 has a soft portion 31E at the rear end side of the rear end side end of the deformation portion 70 and at the center in the width direction of the front surface side. The soft portion 31E constitutes a part of the soft portion E. The soft portion 31E extends in the long axis direction with a substantially constant width in a front view. 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.

The grip portion 30 includes a hard portion 70H provided in the deformation portion 70 and a hard portion 30H provided on the rear end side of the deformation 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 buried on the front side. The recess 31H extends in the major axis direction from the boundary with the deformed portion 70 to the rear end side by a substantially constant length in the front view. The soft portion 31E embedded in the recess 31H is substantially flush with the hard portion 30H exposed on the front surface side.

The grip portion 30 has a soft portion 32E (see fig. 1 and 2) at the center in the width direction of the rear surface side. The soft portion 32E constitutes a part of the soft portion E. The soft portion 32E has an outline substantially identical to the outline of the soft portion 31E in a front view. That is, the soft portion 32E extends in the long axis direction with a substantially constant width in the main view. In rear 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.

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

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

Deformation portion 70

Fig. 4 is a cross-sectional view of the deformed 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 orthogonal to the bristle surface 11. The deformed 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 deformation portion 70 in the longitudinal direction to 15mm or more, the user can sufficiently feel the deformation of the deformation portion 70 when gripping the grip portion 30. Further, by setting the maximum length of the deformation portion 70 in the longitudinal direction to 70mm or less, the deformation portion 70 can be prevented from being excessively deformed easily. In addition, the deformation region of the gripped portion is limited, and the reduction of operability is suppressed. The upper limit of the maximum length of the deformed portion 70 in the longitudinal direction is preferably 70mm or less, more preferably 55mm or less.

The width of the deformed portion 70 is preferably 8mm to 15mm from the viewpoint of sufficiently feeling the deformation and securing operability at the time of gripping.

The thickness of the deformed portion 70 is preferably 6mm to 12mm from the viewpoint of sufficiently feeling the deformation and securing operability at the time of gripping.

As shown in fig. 4, the hard portion 70H is formed in a rectangular shape extending in the width direction with a width larger than the thickness. Assuming that 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 the 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 expression (1) in the entire long axis direction, the hard portion 70H has a bending operation in which bending is easy in the thickness direction and difficult in the width direction. In formula (1), T/W is preferably < 0.35, more preferably T/W is < 0.20.

The center position in the thickness direction of the hard portion 70H is located closer to the back surface side than the center position in the thickness direction of the deformed portion 70 at the position of the apex in the width direction of the outer diameter profile (outer profile) of the soft portion 70E. That is, the hard portion 70H is disposed eccentrically to 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 difficult to bend 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 on the long axis of the entire hard portion 70H (the region excluding the curved surfaces 73H to 76H). When the thickness of the hard portion 70H is less than 0.5mm, the deformation is likely to occur when an external force is applied to the back surface side of the head 10, and thus the durability can be ensured in a planar stress state in which internal stress is unlikely to occur, but the deformation of the deformed portion 70 becomes large, and there is a possibility that the operability at the time of brushing may be lowered. When the thickness of the hard portion 70H exceeds 2.0mm, the deformation is less likely to occur when an external force is applied to the back surface side of the head 10, and thus the planar deformation state in which internal stress occurs may occur, and durability may be reduced. Therefore, by setting the thickness of the hard portion 70H to be 0.5mm or more and 2.0mm or less, durability of the deformed portion 70 can be ensured while maintaining operability at the time of brushing.

Fig. 5 is a front view partially enlarged around 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 front end side, and is 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 first region A1 which is rigid and has a 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 a greater bending strength in the width, thickness, and thickness directions than the hard portion 70H.

The grip portion 30 is formed of a hard resin at least in a part of a cross section orthogonal to the longitudinal direction from at least the tip of the grip portion 30 to the second region A2 in the longitudinal direction. In the first region A1 and the second region A2 of the present embodiment, the proportion of the hard resin is larger than the proportion of the soft resin in the cross section orthogonal to the longitudinal direction. For example, the proportion of the hard resin in the first region A1 in the present embodiment is 100%. The proportion of the hard resin in the second region A2 is 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 with a substantially constant length. Therefore, the width of the hard portion 70H on the rear end side is smaller than the width of the front end side.

The width of the distal end side end portion of the hard portion 70H is smaller than the width of the rear end side end portion of the hard portion 20H of the neck portion 20, depending on the thickness of the soft portion 70E on the outer side in the width direction than the hard portion 70H. 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 according to 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 end side of the hard portion 70H is connected to the hard portion 20H (first region A1) by an arcuate curved surface 73H in a 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 (the first region A1) by an arcuate curved surface 75H in a side view. The arc center of the curved surface 75H is located on the backrest surface side of the harder portion 70H in side view. The curved surface 73H and the curved surface 75H form first thickened portions, respectively, which gradually increase in thickness as the hard portion 70H goes toward the tip side, are thickened, 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 (the second region A2) by an arcuate curved surface 74H in a 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 (the second region A2) by an arcuate curved surface 76H in a side view. The center of the arc of the curved surface 76H is located closer to the backrest surface than the hard portion 70H in side view. The curved surface 74H and the curved surface 76H form second thickened portions, respectively, which become thicker and thicker as the hard portion 70H goes 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 side and the rear 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 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 side. The maximum thickness of the rear end side end portion of the hard portion 70 including both the front side and the rear side second thickened portions is formed smaller than the maximum thickness of the front end side end portion of the hard portion 70 including both the front side and the rear side first thickened portions. A constant thickness portion is provided between the first and second thickened portions (between the curved surfaces 73H and 75H and the curved surfaces 74H and 76H) in the longitudinal direction.

If the curved surfaces 73H to 76H are not present, stress may concentrate at 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. Further, the presence of the curved surfaces 73H to 76H allows both the front end side and the rear end side of the deforming portion 70 to have flexibility and deform.

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, for example, a resin having a flexural modulus (JIS 7171) of 1500MPa to 3500MPa, for example, polyacetal resin (POM) is cited. The flexural modulus of the hard portion H is more preferably 2000MPa to 3500 MPa. By using a raw material with a high elastic modulus (e.g., POM), the shape can be thinned or thinned.

As shown in fig. 4, the soft portion 70E has 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 back surface side of the center of the deformed portion 70 (soft portion 70E) in the thickness direction.

The occupancy rate of the cross-sectional area of the hard portion 70H 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 thickness-fixing portion. By setting the occupancy of the cross-sectional area of the hard portion 70H to 35% or less in the entire long axis direction, the bending strength of the deformed portion 70 to the back surface side can be reduced.

As a material of the soft portion E, from the viewpoint of maintaining the recommended brushing load value, 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, as an example. Examples of the soft resin include an elastomer (e.g., an olefin-based elastomer, a styrene-based elastomer, a polyester-based elastomer, and a polyurethane-based thermoplastic elastomer), and silicone. From the viewpoint of excellent mixing with polyacetal resin, styrene-based elastomer is preferable.

In the toothbrush 1 described above, when an external force is applied to the head 10 toward the rear surface 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 deformation portion 70 are rigid and rigid with respect to the hard portion 70H, and therefore the deformation portion 70 disposed between the first region A1 and the second region A2 is not 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 of the rear end side formed by the curved surfaces 74H, 76H is smaller than the maximum thickness of the first thickened portion of the front end side formed by the curved surfaces 73H, 75H, so that the bending strength is small, and therefore, the bending 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 deformed portion 70 is suppressed.

When the bending operation is performed from the bending of the rear end side, the front end side of the deformation portion 70 starts to bend, but since the width of the front end side is larger than the width of the rear end side, the maximum thickness of the first thickening portion of the front end side formed by the curved surfaces 73H, 75H is larger than the maximum thickness of the second thickening portion of the rear end side formed by the curved surfaces 74H, 76H, and the bending strength is large, the stress concentration is relaxed compared with the rear end side, and excessive bending of the deformation portion 70 is suppressed. Further, since the first region A1 having rigidity exists, propagation of stress to the neck portion 20 on the tip end side of the deformed portion 70 is further suppressed.

That is, the rear end side of the deformation portion 70 plays a role in promoting clear bending, and the front end side of the deformation portion 70 plays a role in suppressing excessive bending. Thus, even if the deformation portion is bent, the grip portion 30 on the rear end side of the deformation portion 70 is not bent, and therefore, an effect that the operability of the handle is not affected can be obtained. Further, the deformation portion distal end portion is suppressed from being excessively bent, and stress is hardly concentrated due to the cushioning effect, so that, for example, even if the thickness of the head portion is made thin to 2.0 to 4.0mm, and the minimum width and thickness of the neck portion are made thin to a specification of 3.0 to 4.5mm or less, the bending strength at the boundary between the neck portion and the deformation portion can be ensured.

Further, since the deformation 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 deformation region (the deformation portion 70) and the non-deformation region (the neck portion 20 and the grip portion 30 excluding the deformation portion 70) are clearly divided. This allows the design to improve flexibility in the deformed region without considering both the strength and the contrast in strength when compared with the non-deformed region to be strongly reflected.

In order to exhibit the function of the distal end side of the deformation 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 radii of the curved surfaces 73H, 75H forming the first thickening portion of the distal end side of the hard portion 70H are 15mm or less, preferably 13mm or less, and the length in the longitudinal direction of the curved surfaces 73H, 75H (the length in the longitudinal direction from the connecting portion of the curved surfaces 73H, 75H with the hard portion 20H of the neck portion 20 to the length in the longitudinal direction of the hard portion 70H, where the thickness is constant) is preferably less than 35% of the length in the longitudinal direction of the deformation portion 70.

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 radii of the curved surfaces 74H and 76H forming the second thickened portion of the rear end side of the hard portion 70H are 10mm or less, preferably 8mm or less, and the length in the longitudinal direction of the curved surfaces 74H and 76H (the length in the longitudinal direction from the connection portion between the curved surfaces 74H and 76H and the hard portion 30H to the constant thickness of the hard portion 70H) is preferably less than 35% of the length in the longitudinal direction of the deformed portion 70.

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

As a result, in the toothbrush 1 according to the present embodiment, it is possible to sufficiently reduce the excessive brushing pressure while imparting a gentle and comfortable operability to the teeth and gums without damaging the gums.

Second embodiment

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

Fig. 7 (a) is a front view of a cross-sectional view including a plane including the center in the thickness direction partially cutting the toothbrush 1 according to the second embodiment, fig. 7 (B) is a cross-sectional view including a plane including the center in the width direction cutting the toothbrush 1, and fig. 7 (C) is a rear view of a cross-sectional view including a plane including the center in the thickness direction partially cutting a part of the toothbrush 1. In fig. 7 (a) and (C), a cross-sectional view is taken from a position L1, which is a predetermined distance away from a position L0 of a boundary between the neck portion 20 and the grip portion 30 toward the rear end side, to the rear end side, in front view (or rear view), and is cut by a plane including the center in the thickness direction. In these drawings, the same components as those of the toothbrush 1 according to 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 of the toothbrush 1 of the second embodiment in the longitudinal direction is longer than that of the deformed portion of the toothbrush 1 of the first embodiment. The position L5 of the rear end portion of the deforming portion 70 is located on the rear end side of the center in the longitudinal direction of the grip portion 30. The length 70L of the deformed portion 70 in the longitudinal direction is longer than half the length of the grip portion 30 in the longitudinal direction.

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 widens 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 narrows from the position L1 to the position L2 as going toward the rear end side in a circular arc-shaped locus whose center is located on the outer side in the width direction in a plan view. The width of the hard portion 70H gradually increases from the position L4 to the position L5 as the locus of the circular arc shape whose center is located on the outer side in the width direction in plan view becomes wider toward the rear end side.

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 L2 to the position L3 as a constant thickness portion having a substantially constant thickness. The thickness of the hard portion 70H gradually increases from the position L3 to the position L5 by 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 fixed thickness portion in the longitudinal direction is preferably 10% or more and 90% or less, more preferably 20% or more and 70% or less, of the length of the grip portion 30 in the longitudinal direction. If the length 77L of the fixed thickness portion in the longitudinal direction is smaller than 10% of the length of the grip portion 30 in the longitudinal direction, there is a possibility that the brush will not be deformed flexibly when excessive brushing pressure is applied to the head 10. When the length 77L of the fixed thickness portion in the longitudinal direction exceeds 90% of the length of the grip portion 30 in the longitudinal direction, the deformation becomes large when excessive brushing pressure is applied to the head 10, and there is a possibility that operability during brushing may be degraded. By setting the length 77L of the fixed thickness portion in the longitudinal direction to be 10% or more and 90% or less of the length of the grip portion 30 in the longitudinal direction, soft and comfortable operability can be imparted to the teeth and gums without damaging the gums, and excessive brushing pressure can be sufficiently reduced. Further, for example, when the grip portion 30 is gripped by the palm grip method, the entire grip portion 30 can be appropriately fitted to the shape of the hand.

In the case of the toothbrush 1 of the second embodiment, it is preferable that the length in the longitudinal direction of the positions L4 to L5 and the length in the longitudinal direction of the positions L3 to L5 are longer than the length in the longitudinal direction of the positions L1 to L2.

Thus, even in the case of the long deformed portion 70, excessive bending of the grip portion 30 on the tail side can be suppressed. For the same reason, the length in the longitudinal direction of the positions L3 to L5 is preferably longer than the length in the longitudinal direction of the positions L4 to L5.

Examples (example)

The present invention will be described in detail with reference to the following examples, but the present invention is not limited to the following examples and can be implemented by appropriately changing the examples within a range not departing from the gist 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 ].

The toothbrushes according to the first embodiment were used as samples in examples 1 to 5 and comparative examples 1 to 2. Example 6 and comparative example 3 were carried out using a toothbrush according to the second embodiment as a sample. Comparative example 4a toothbrush manufactured by lion king corporation having no deformed portion "CLINICA ADVANTAGE column ordinary bristles" was used as a sample.

[ Evaluation method ]

Impact strength, fatigue strength and usability were evaluated in examples 1 to 6 and comparative examples 1 to 4, respectively.

Regarding the impact strength, a 60mm portion was fixed from the rear end of the grip portion, and a load of 2kg was applied from a height of 60cm to the head (number of samples; n=5).

As a result of the impact strength, the case where the head was not broken and no crack was generated was designated "o" (OK), the case where the head was not broken but the crack was not more than 0.2mm was designated "Δ" (OK), and the case where the head was broken was designated "×" (NG).

For fatigue strength, a 60mm portion was fixed from the rear end of the grip, and a displacement of 50mm (number of samples; n=5) was repeatedly applied to the head at a speed of 240 rpm.

The case where the crack was not generated and broken when the load was applied 100 ten thousand times was designated as "good" (OK), the case where the crack was not broken but was not more than 0.2mm was designated as "delta" (OK), and the case where the crack was broken was designated as "×" (NG).

For evaluation of usability, each sample was used for 5 days and then investigated. Panelists were conducted with 6 panelists. The investigation items were evaluated in 7 stages, respectively, and in average, for "a feeling that the grip portion was deformed and the brushing pressure was reduced, and a feeling that the grip portion was fitted to the hand during brushing" were both able to be stably brushed. The average of the scores is to round the second decimal place as the number of digits to the first decimal place.

(1) The grip portion is deformed to reduce the feeling of brushing pressure

Score 7 points: feel intense, 6 points: very pleasant, 5 points: slightly feel, 4 points: feel neither strong nor weak, 3 points: less perceived, 2 points: hardly felt, 1 point: the evaluation was performed in 7 stages with no sense at all.

Evaluation + (excellent): 6.0 minutes or more, excellent: 5.5 minutes or more, O (good): 4.5 minutes or more, Δ (not bad): 4.0 points or more, x (bad): more than 1 and less than 4.0 minutes.

(2) Feeling of coincidence of the holding part during brushing

Score 7 points: feel intense, 6 points: very pleasant, 5 points: slightly feel, 4 points: feel neither strong nor weak, 3 points: less feeling, 2 minutes: almost no feeling, 1:: the evaluation was performed in 7 stages with no sense at all.

Evaluation (good): 4.5 minutes or more, Δ (not bad): 4.0 points or more, x (bad): more than 1 and less than 4.0 minutes.

[ Table 1]

As shown in table 1, in the samples of examples 1 to 6 having the deformed portion 70, the hard portion 70H, and the cross-sectional area of the hard portion 70H in the cross-section orthogonal to the longitudinal direction having the thickness T and the width W satisfying the relationship of T/W <1 and having the occupancy rate of 35% or less with respect to the cross-sectional area of the deformed portion 70, both the impact strength and the fatigue strength satisfy the predetermined values. In addition, regarding usability, in the samples of examples, "a feeling of being able to stably brush while the grip portion is deformed to reduce the brushing pressure" and "a feeling of being fitted with the hand at the time of brushing" were all well evaluated.

In contrast, in the samples of comparative examples 1, 3, and 4 having the deformed portion and not satisfying the relationship of T/W < 1, the effect of reducing the brushing pressure was insufficient because of the deflection in the side direction, and the "feeling of stable brushing while the grip portion was deformed and the brushing pressure was reduced" was not well evaluated. In the sample of comparative example 2 in which the occupancy rate of the cross-sectional area of the hard portion 70H to the cross-sectional area of the deformed portion 70 exceeds 35%, the soft portion is not cushioned when the load is applied, and the stress is directly transmitted to the hard portion, so that the head portion breaks due to both the impact strength and the fatigue strength.

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

For example, in the above embodiment, the soft portion 70E is illustrated as covering the entire periphery of the hard portion 70H, but the present invention is not limited to this configuration, and a configuration may be adopted in which a part of the hard portion 70H is uncovered and exposed.

In the above embodiment, the configuration in which the thickened portions are provided on both the front side and the rear side of the hard portion 70H has been described as an example, but the thickened portions may be provided on only one of the front side and the rear side.

[ INDUSTRIAL APPLICABILITY ]

The present invention can be applied to toothbrushes.

Description of the reference numerals

1 … Toothbrush; 2 … handle body; 10 … heads; 11 … hair-planting surfaces; 20 … neck; 30 … grip; 70 … deformations; a1 … first region; a2 … second region; E. 31E, 32E, 70E … soft portion; H. 70H … hard portion; 73H, 75H … curved surfaces (first thickened portions); 74H, 76H … curved surfaces (second thickened portions).

Claims

1. A toothbrush, characterized by comprising: a head part which is arranged at the front end side in the long axis direction and is provided with a hair planting 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 is formed of a hard resin,

The toothbrush has:

A deformation portion which is arranged on the holding portion and deforms due to an 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 the first direction; and

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

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

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,

The occupancy of the cross-sectional area of the hard portion relative to the cross-sectional area of the deformed portion in the cross-section orthogonal to the longitudinal direction is 35% or less in the entire longitudinal direction,

When the thickness of the hard portion in the first direction is T and the width of the hard portion in a second direction orthogonal to the long axis direction and the first direction is W, the relation of T/W < 1 is satisfied in the whole long axis direction,

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

2. The toothbrush of claim 1, wherein,

The hard portion has: a first thickening portion that is connected to the first region so as to gradually increase in thickness in the first direction toward the distal end side in the longitudinal direction; and a second thickening portion that is connected to the second region so as to gradually increase in thickness in the first direction toward the rear end side in the longitudinal direction.

3. The toothbrush according to claim 2, wherein,

The maximum thickness of the second thickening is less than the maximum thickness of the first thickening.

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

The minimum thickness of the hard portion in the first direction is 0.5mm or more and 2.0mm or less.

5. The toothbrush according to any one of claim 1 to 3, wherein,

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

6. The toothbrush according to any one of claim 1 to 3, wherein,

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

7. The toothbrush according to any one of claim 1 to 3, wherein,

The minimum thickness of the neck in the first direction and the minimum width of the neck in the second direction are 3.0mm or more and 4.5mm or less.

8. The toothbrush according to any one of claim 1 to 3, wherein,

The hard portion is disposed eccentrically to the rear surface side in the thickness direction.