CN113995224B

CN113995224B - Toothbrush with tooth brush

Info

Publication number: CN113995224B
Application number: CN202111322290.8A
Authority: CN
Inventors: 龟井诚一; 金丸直史
Original assignee: Lion Corp
Current assignee: Lion Corp
Priority date: 2016-10-28
Filing date: 2017-09-13
Publication date: 2023-07-21
Anticipated expiration: 2037-09-13
Also published as: CN113995223A; SG11201903712UA; KR20190069391A; WO2018079114A1; KR102556409B1; JP7086002B2; CN113995224A; CN109890247A; CN109890247B; SG10202104233SA; JPWO2018079114A1

Abstract

Provided is a toothbrush which can ensure the operability of a handle portion and the operability in the oral cavity. The toothbrush (1) is provided with a bristle planting part (11), a head part (12), a neck part (13) and a handle part (14), wherein the thickness t of the head part (12) is more than or equal to 2.0mm and less than or equal to 4.0mm, and the minimum width W1 and the minimum thickness D1 of the neck part (13) are more than or equal to 3.0mm and less than or equal to 4.5mm. A curved surface (13 a) is formed on the bristle surface (12 a) side of the rear end side of the neck, the curved surface being arranged on the bristle surface side in a center position and having a concave circular arc profile in a side view. An angle [ theta ] formed by a straight line [ N ] connecting a center point in the thickness direction of a handle part [ 14 ] at a grip center position of a toothbrush [ 1] and a center point in the thickness direction of a head part [ 12 ] at a center position of a bristle planting part [ 11 ] and a plane [ P ] constituting a bristle planting surface [ 12a ] is 5.0 DEG to 10.0 deg.

Description

Toothbrush with tooth brush

Technical Field

The present application is a divisional application of patent application of the invention named toothbrush, with application number 201780066471.4, filed on 2017, 9 and 13.

The present invention relates to toothbrushes.

The present application claims priority from japanese patent application No. 2016-212030, filed in japan on the basis of 28 of 10 in 2016, and the contents thereof are incorporated herein by reference.

Background

Patent documents 1 to 3 disclose toothbrushes in which the thickness of the head is reduced in consideration of the operability in the oral cavity and the like. When the head is made thinner, there is a problem that strength is lowered. Therefore, a resin having high strength such as polyacetal resin (POM) is used. In particular, in the case of flat wire type bristle setting in which bristles are held by driving a flat wire (flat plate) made of metal into a head made of resin, there are cases where the bristle setting strength and the folding endurance of the head are insufficient.

Prior art literature

Patent literature

Patent document 1: JP Japanese patent laid-open No. 7-143914

Patent document 2: JP-A2011-4852

Patent document 3: JP publication No. 2011-200296

Disclosure of Invention

Problems to be solved by the invention

The inventors found after study that: in the toothbrush described above, when the neck portion connecting the head portion and the handle portion is thick, the improvement effect of the intra-oral operability due to the thinning of the head portion is impaired. In particular, when the neck portion is widened, not only is operability further impaired, but also the thinness of the head portion is not noticeable in appearance, and the impression of the commodity is impaired. However, when the neck portion is thinned, excessive deflection may occur, which may cause problems in operability. Further, further improvement in strength is also required. In particular, in the case of using general-purpose resins such as polypropylene (PP) which are generally used in toothbrushes, the problem is more remarkable.

One embodiment of the present invention has been made to solve the above-described problems, and an object thereof is to provide a head-thinned toothbrush which can achieve good operability.

Means for solving the problems

In order to achieve the above object, a toothbrush according to one aspect of the present invention is a toothbrush comprising a bristle-planting portion configured by a plurality of bundles of bristles, a head portion on which the bristle-planting portion is provided, a neck portion extending from the head portion, and a handle portion extending from the neck portion, wherein the thickness of the head portion is 2.0mm or more and 4.0mm or less, the minimum width and minimum thickness of the neck portion are 3.0mm or more and 4.5mm or less, and a curved surface having a circular arc profile in which a center position is arranged on the bristle-planting surface side and the bristle-planting surface side is recessed in a side view is formed on the bristle-planting surface side on the rear end side of the neck portion, and an angle formed between a straight line connecting a center point in the thickness direction of the handle portion at the grip center position of the toothbrush and a center point in the thickness direction of the head portion at the center position of the bristle-planting portion and a plane configuring the bristle-planting surface is 5.0 degrees or more and 10.0 degrees or less.

In the toothbrush according to one embodiment of the present invention, the flexural modulus of the constituent material of the neck portion may be 1000MPa to 2200 MPa.

In the toothbrush according to one embodiment of the present invention, the neck portion may be made of polypropylene resin.

Effects of the invention

According to one embodiment of the present invention, a thin-head toothbrush that can achieve good operability can be realized.

Drawings

Fig. 1 is a plan view of a toothbrush according to an embodiment of the present invention.

Fig. 2 is a side view of the toothbrush.

[ description of the symbols ]

1 … toothbrush; 11 … hair-planting parts; 12 … head; 12a … flocked surfaces; 13 … neck; 14 … handle portion; 17 … hair bundles.

Detailed Description

An embodiment of the present invention will be described below with reference to fig. 1 and 2.

The following embodiments are illustrative of an embodiment of the present invention, and the present invention is not limited to the embodiment, and can be arbitrarily modified within the scope of the technical idea of the present invention. In the following drawings, for ease of viewing each component, the scale and the number of the components may be different depending on the size of the component.

Fig. 1 is a plan view of the toothbrush of the present embodiment.

Fig. 2 is a side view of the toothbrush.

As shown in fig. 1 and 2, a toothbrush 1 according to the present embodiment includes: the hair-planting portion 11 is provided with a head portion 12 of the hair-planting portion 11, a neck portion 13 extending from a base end side of the head portion 12, and a handle portion 14 extending from a base end side of the neck portion 13. That is, the head 12 and the neck 13 are integrally formed with the handle portion 14. Hereinafter, the integrally formed parts of the head 12, neck 13 and handle portion 14 are referred to as a handle body 15. In fig. 1, the hair-planting portion 11 is not shown.

The upper surface of the head 12 provided with the bristle part 11 is referred to herein as a bristle surface 12a. As shown in fig. 1 and 2, a plane P (virtual plane) constituting the bristle surface 12a is defined as an XY plane, a direction in which the entire handle body 15 extends is defined as an X-axis direction, and a direction perpendicular to the X-axis is defined as a Y-axis direction. The normal direction of the plane P is taken as the Z-axis direction. In the following description, the dimension of each member in the Y-axis direction is referred to as the width of the member, the dimension of each member in the Z-axis direction is referred to as the thickness of the member, and the dimension of each member in the X-axis direction is referred to as the length of the member.

The handle body 15 is integrally formed in a long shape, and can be manufactured by injection molding using a resin as a material, for example. Examples of the constituent materials of the handle body 15 include polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polycyclohexamethylene terephthalate (PCT), polyacetal (POM), polyethylene naphthalate (PEN), polystyrene (PS), acrylonitrile Butadiene Styrene (ABS), cellulose Propionate (CP), polyarylate, polycarbonate, and acrylonitrile styrene copolymer resin (AS). Among these resin materials, POM, PBT, PEN and other materials are preferably used in view of high strength and easiness of thinning the head.

In particular, polypropylene generally has high versatility, is easy to process and low in cost as compared with resins such as polyacetal, but has a property of low flexural modulus. For example, the flexural modulus of polyacetal is about 2500MPa, while the flexural modulus of polypropylene is about 1500 to 2000 MPa. Therefore, polypropylene has been a difficult material to use in the past as a material for toothbrushes having thin heads and thin necks. However, a resin having a low flexural modulus such as polypropylene may be used by adopting the toothbrush shape of the present embodiment described later.

In the present embodiment, the flexural modulus of the constituent material of the grip body 15, particularly the neck portion 13, is preferably 1000MPa to 2200 MPa. When the flexural modulus is less than 1000MPa, sufficient strength may not be obtained when the neck portion 13 is thinned. Further, if the flexural modulus exceeds 2200MPa, the hardness increases, but on the other hand, the hardness may become brittle.

The resin may be used alone of 1 kind, or may be used in combination of 2 or more kinds. In the handle body 15, a part or the whole of the handle portion 14 may be covered with a soft resin. By covering a part or the whole of the grip portion 14 with soft resin, the sense of fit of the hand when the user grips the grip portion 14 can be improved, and slipping of the gripped fingers can be prevented. The soft resin is preferably a resin having a shore a of 90 or less, and more preferably a resin having a shore a of 10 to 40. Examples of such soft resins include elastomer resins such as polyolefin-based elastomers, styrene-based elastomers, polyester-based elastomers, and polyurethane-based thermoplastic elastomers, and silicone resins.

The overall length of the handle body 15 may be determined according to operability and the like. The overall length of the handle body 15 is, for example, about 100 to 200 mm.

The head 12 has a substantially quadrangular flat plate shape with 4 tops cut by a curve in a plan view. A plurality of implantation holes 12h are provided in the implantation surface 12a which is the upper surface of the head 12. The tufts 17 having the bristles bundled are implanted into the implantation holes 12h, whereby the bristle-implanted portions 11 composed of the plurality of tufts 17 are formed. Of the plurality of implantation holes 12h, a distance d1 from the implantation hole 12h located on the most distal side of the head 12 to the distal end of the head 12 and a distance d2 from the implantation hole 12h located on the most proximal side of the head 12 to the proximal end of the head 12 are set to be equal. In other words, a boundary position K1 between the neck 13 and the head 12 described later is the following position: from the implantation hole 12h located on the most proximal side of the head 12, the position is deviated toward the neck 13 by a distance equal to the distance d 1.

The size of the head 12 may be determined in consideration of characteristics such as intra-oral operability. When the width of the head 12 is too large, the intraoral operability is lowered, and when the width is too small, the number of hair bundles 17 for hair implantation becomes too small, and the cleaning effect is easily impaired. Therefore, the width of the head 12 can be set to, for example, about 5mm to 16 mm.

If the length of the head 12 is too long, the intraoral operability is easily impaired, and if the length is too short, the number of hair bundles 17 to be planted becomes too small, and the cleaning effect is easily impaired. Therefore, the length of the head 12 can be set in the range of 10mm to 33mm, for example.

The shape of the implantation hole 12h is not particularly limited, and may be circular such as a perfect circle or an ellipse, or polygonal such as a triangle or a quadrangle. The number of implantation holes 12h is not particularly limited, and may be set to a range of 10 to 60, for example. The diameter of the implantation hole 12h may be determined according to the thickness of the hair bundle 17, and may be set in a range of 1mm to 3mm, for example. The arrangement pattern of the implantation holes 12h is not particularly limited, and may be any arrangement pattern such as a so-called lattice pattern or a staggered pattern.

As the bristles constituting the tufts 17, bristles (tapered bristles) having diameters gradually smaller toward the bristle tips, bristles (straight bristles) having substantially the same outer diameter except for the spherical portions of the bristle tips, are exemplified. As the material of the bristles, for example, polyamide such as 6-12 nylon or 6-10 nylon, synthetic resin materials such as PET, PBT, polytrimethylene terephthalate (PTT), polyester such as PEN or polybutylene naphthalate (PBN), polyolefin such as PP, olefin elastomer, and styrene elastomer can be used. These resin materials may be used singly or in combination of 1 kind or 2 or more kinds. In addition, the bristles may be of a multiple core construction having: a core part and at least 1 layer of sheath part arranged outside the core part.

The cross-sectional profile of the bristle is not particularly limited, and examples thereof include circular shapes such as a perfect circle and an ellipse, polygonal shapes such as a triangle, a quadrangle, a pentagon and a hexagon, star-shaped, three-leaf clover-shaped, four-leaf clover-shaped, and the like.

The thickness of the bristles is not particularly limited, and when the cross-sectional profile is circular, the thickness can be set to 3mil to 11mil (1 mil=1/1000 inch=0.025 mm), for example. The tufts may be made up of bristles all of the same thickness, or may be made up of more than 2 bristle combinations of different thickness. The length of the bristles is not particularly limited, and may be set to 6mm to 12mm, for example.

As shown in fig. 2, a curved surface 14a having a circular arc profile in which the center position (curvature center) is disposed on the side opposite to the bristle surface 12a (on the lower side than the handle portion 14 in fig. 2) and the bristle surface 12a side is convex in a side view is formed on the bristle surface 12a side of the handle portion 14. Similarly, a curved surface 14b having a circular arc profile, which is arranged at a center position on the side opposite to the bristle surface 12a and has a convex side of the bristle surface 12a in a side view, is formed on the side opposite to the bristle surface 12a on the front end side of the handle 14.

Further, a curved surface 13a having a circular arc contour, which is arranged on the bristle surface 12a side (upper side than the grip portion 14 in fig. 2) at a center position (curvature center) and which is recessed on the bristle surface 12a side in a side view, is formed on the bristle surface 12a side of the neck portion 13. More specifically, regarding the neck portion 13, a surface (curved surface or plane) on the bristle surface 12a side in the thickness direction of the handle portion 14 continuing from a front end side region to a rear end side region in the longitudinal direction intersecting the head portion 12 forms a curved surface 13a having a concave circular arc profile on the bristle surface 12a side in a side view seen from the width direction intersecting the longitudinal direction and the thickness direction, and is curved. The curvature center of the curved surface 13a is disposed on the upper side than the curved surface 13a in the thickness direction. Similarly, a curved surface 13b having a circular arc contour, which is arranged on the bristle surface 12a side (upper side) at a center position (curvature center) and is concave on the bristle surface 12a side in a side view, is formed on the rear end side of the neck portion 13 opposite to the bristle surface 12a.

The curved surface 13a and the curved surface 14a continuously change in the crossing angle between the tangent line and the bristle surface 12a in the side view angle as the length direction of the handle portion 14 extends, but cross at an angle α1 at which the crossing angle between the tangent line and the curved surface 13a is not 0 degrees or 180 degrees at the crossing portion of the curved surface 13a and the curved surface 14a. Therefore, a ridge line K2 is formed at the intersection of the curved surface 13a and the curved surface 14a.

The curved surface 13b and the curved surface 14b also extend along the longitudinal direction of the handle portion 14, and the intersecting angle between the tangent line in the side view and the bristle surface 12a continuously changes, but intersect at the intersection of the curved surface 13b and the curved surface 14b at an angle α2 at which the intersecting angle of the tangent lines is not 0 degrees or 180 degrees. Therefore, a ridge line K3 is formed at the intersection of the curved surface 13b and the curved surface 14b. Therefore, the neck portion 13 and the handle portion 14 are formed in a substantially S-shape in the side view by connecting the curved surfaces 14a, 14b having the convex circular arc profile on the side of the bristle surface 12a in the side view in the longitudinal direction sandwiching the ridge lines K2, K3 and the curved surfaces 13a, 13b having the concave circular arc profile on the side of the bristle surface 12a in the side view in the longitudinal direction sandwiching the ridge lines K2, K3.

The boundary of the rear end side of the neck portion 13 is defined by ridge lines K2, K3. Therefore, the rear end side of the ridge lines K2 and K3 is a range in which the handle portion 14 is disposed, and the neck portion 13 is disposed in a range between the range in which the head portion 12 is disposed and the range in which the handle portion 14 is disposed.

The end portion on the bristle surface 12a side (the side at the rear end of the ridge line K2 in the side view) on the front end side of the handle portion 14 is a finger contact portion 19. The apex of the tip end side of the finger contact portion 19 is defined by a ridge line K2. As shown in fig. 1, the vertex position (ridge line K2) is a position of a vertex that is the shortest distance to the head 12 in the front view. The user grips the handle portion 14 in such a manner as to press the thumb against the finger contact portion 19, whereby the toothbrush 1 can be stably operated.

The neck portion 13 integrally connects the head portion 12 and the handle portion 14. The neck portion 13 is formed in the following shape as an example: the shape of the diameter gradually increases from the boundary position K1 between the head 12 and the neck 13 (the front end of the neck 13) to the position of the handle 14, which is slightly narrowed, to a small cross-sectional area, and the cross-sectional area is maintained to extend toward the rear end side, and gradually increases from the rear end side to the boundary K2 between the handle and the handle 14. As described above, the neck portion 13 gradually increases in thickness from the head portion 12 side toward the handle portion 14 side, so that the neck portion 13 can absorb deflection even when the toothbrush 1 is used in various holding methods or brushing methods, and the usability is excellent. Among them, the neck portion 13 needs to have elasticity and moderate flexibility from the viewpoint of feeling in use.

In order to allow the neck 13 to contact the lips when the head 12 is inserted into the oral cavity, the length of the neck 13 is preferably 25mm to 70mm.

As shown in fig. 1, the grip center position G1 of the toothbrush 1 is located on the grip portion 14. The grip center position G1 is defined as a position 37mm apart from the ridge line K2 on the rear end side of the handle portion 14.

As a method of holding a toothbrush, there are known a "grasping type" in which a thumb is placed near a finger contact portion and the handle portion is held by the palm as a whole, and a "pen-holding type" in which a thumb is placed near a finger contact portion and held like a pen. The present inventors have intensively studied the position of the force applied when operating a toothbrush in the case of holding various toothbrushes with various holding methods. The results showed that: a part of the finger is placed at a position apart from the apex of the finger contact portion (the position of the ridge line K2) by an average of 37mm, which becomes one of the centers of the operation points. Thus, this position is defined as the grip center. Furthermore, it is also known that: this position is approximately coincident with the center of gravity of many conventional toothbrushes.

As shown in fig. 2, when a virtual straight line connecting the center point G2 in the thickness direction of the handle portion 14 at the grip center position G1 of the toothbrush 1 and the center point S2 in the thickness direction of the head portion 12 at the center position S1 (see fig. 1) of the bristle part 11 is set as a straight line N, the straight line N is located above the plane P (+z direction). In other words, the handle body 15 has the following curved shape: the handle portion 14 having the grip center position G1 is curved so as to be positioned closer to the hair-planting portion 11 than the hair-planting surface 12a of the head portion 12.

The inventors found that: in the conventional toothbrush in which the handle body extends approximately linearly, when the head is thinned and the neck is thinned, the head and the neck are deflected, and the bristle part is easily displaced toward the back side of the head (in the-Z axis direction in fig. 2). In particular, when the neck is deflected during the brushing, the bristle part is displaced toward the back side of the head (i.e., in a direction away from the teeth or gums) from the normal position, and it is difficult to sufficiently transmit the force applied to the handle part to the bristle part. As a result, it was determined that the operability of the handle portion was significantly lowered.

Accordingly, the present inventors have made intensive studies to think that: as in the toothbrush 1 of the present embodiment described above, bending of the handle body 15 toward the handle portion 14 of the handle body 15 closer to the bristle part 11 than the plane P constituting the bristle surface 12a can cancel out the deflection of the head 12 and the neck 13 by bending the handle body 15 when parameters such as the angle θ formed by the straight line N and the plane P are optimized. As described above, according to the toothbrush 1 of the present embodiment, even when the head 12 and the neck 13 are bent when the head 12 and the neck 13 are thinned, the handle operability can be maintained satisfactorily, and the toothbrush 1 excellent in both the intra-oral operability and the handle operability can be realized.

Hereinafter, characteristic design parameters of the toothbrush 1 of the present embodiment will be described.

[ thickness t of head ]

The thinner the thickness t of the head 12, the more the intraoral operability can be improved, but if too thin, the strength of the head 12 tends to become insufficient. Therefore, the thickness t of the head 12 can be determined in consideration of the constituent material of the handle body 15, the flexural modulus, and the like. The thickness t of the head 12 may be set in the range of 2.0mm to 4.0 mm. The thickness t of the head 12 is more preferably about 2.5mm to 3.5 mm.

[ minimum width of neck W1]

The smaller the minimum width W1 of the neck portion 13 is, the more the intraoral operability can be improved, but if it is too small, the strength of the neck portion 13 tends to be insufficient. Therefore, the minimum width W1 of the neck portion 13 can be determined in consideration of the constituent material of the handle body 15, the flexural modulus, and the like. The minimum width W1 of the neck 13 may be set to 3.0mm to 4.5mm. The minimum width W1 of the neck portion 13 is more preferably about 3.5mm to 4.3mm.

[ minimum thickness of neck D1]

The minimum thickness D1 of the neck 13 may be defined as: the thickness of the neck portion 13 at a position where the width of the neck portion 13 in the X-axis direction is minimum. That is, in the toothbrush 1 of the present embodiment, the cross-sectional shape perpendicular to the extending direction of the neck portion 13 is approximately circular, and the position where the width of the neck portion 13 is smallest and the position where the thickness is smallest coincide with each other in the X-axis direction. However, the cross-sectional shape perpendicularly intersecting the extending direction of the neck portion 13 may not necessarily be a circle, and may be a polygon, for example. The cross-sectional shape perpendicular to the extending direction of the neck portion 13 may be different depending on the position in the X-axis direction, and the position where the width of the neck portion 13 is minimum and the position where the thickness is minimum may not necessarily coincide.

The smaller the minimum thickness D1 of the neck portion 13, the more the oral operability can be improved, similarly to the minimum width W1 of the neck portion 13, but if too small, the strength of the neck portion 13 tends to be insufficient. Therefore, the minimum thickness D1 of the neck portion 13 can be determined in consideration of the conditions such as the constituent material of the handle body 15 and the flexural modulus. The minimum thickness D1 of the neck 13 may be set to 3.0mm to 4.5mm. The minimum thickness D1 of the neck portion 13 is more preferably about 3.5mm to 4.3mm. In the case of the present embodiment, the cross-sectional shape perpendicularly intersecting the extending direction of the neck portion 13 is approximately circular, and therefore the width and the thickness are the same. That is, the minimum diameter of the neck portion 13 is preferably 3.0mm to 4.5mm, more preferably 3.5mm to 4.3mm.

Here, the form factors of the front end region and the rear end region of the neck portion 13 will be described.

The tip region of the neck 13 (region between the boundary position K1 of the head 12 and the position 10mm away from the rear end side of the boundary position K1) is a region that enters the oral cavity and has a large physical interference with the periphery of the cleaning portion. Therefore, from the viewpoint of intra-oral operability, the shape in the side view on the bristle surface 12a side of the head 12 in this region is preferably on the same plane (on the same plane) as the bristle surface 12a or in a parallel relationship with the bristle surface 12a. Therefore, it is preferable that the thickness of the neck portion 13 is D, the thickness of the upper side of the neck portion 13 than the plane including the bristle surface 12a in the side view is D11, and the thickness of the lower side of the neck portion 13 than the plane is D12 (d=d11+d12), D12> D11 is always performed in the neck front end region, and the ratio of D12 to D11 is shifted constantly (the variation of D11/D12 in the above front end region is in the range of 1.0±0.15).

The rear end region of the neck portion 13 (the region between the ridge line K2 and the position 20mm away from the front end side of the ridge line K2) is different from the front end region, and is rarely taken into the oral cavity. In order to suppress excessive deflection due to the thin head and neck (that is, to improve the intraoral operability and the handle operability), the rear end region is provided with a function of imparting a shape change so as to establish an appropriate grip center point angle θ and grip center point height h. In particular, since the shape (upper side) of the bristle surface 12a side of the rear end region mainly contributes to the setting of the grip center point angle θ, the shape in the side view thereof is set to a circular arc shape steeper (more curvature) than the front end region. Further, since the thickness is increased by the shape change, the deflection can be controlled at the root of the neck portion 13 where the load by the brushing is easily concentrated.

On the other hand, the rear surface side (lower side) of the rear end region has a similar arc shape in accordance with the shape change in the side view of the upper side, but has a circular arc shape that is more gentle (less curvature) than the upper side because the thickness needs to be increased to suppress the deflection. At this time, the thickness D11 at a position shifted 20mm from the ridge K2 toward the head 12 side (the tip side) is set to be the thickness D11 (20), the thickness D11 (10) is set to be 10mm from the ridge K2 toward the tip side, and the thickness D11 (0) is set to be the ridge, and the following relationship is also established when the thickness D12 is similarly expressed.

(1) At a position 20mm from the front end side of the ridge line K2:

of the thicknesses D at this position, the upper thickness D11 accounts for 40±10%.

At a position 10mm from the front end side of the ridge line K2:

the thickness D11 at the upper side of the thickness D at this position is 40% to 90%, preferably 60% to 80%.

At the position of 0mm (ridge K2):

the thickness D11 at the upper side of the thickness D is 45% or more, preferably 75% or more, more preferably 80% or more, and even more preferably 85% or more. The upper limit is preferably 95% or less, and more preferably 90% or less.

Regarding the proportion of the thickness D11, the larger the angle θ becomes, the larger the value becomes. In addition, when the head 12 is made thin, the thickness itself is small, so that the ratio of the upper thickness D11 is further increased to obtain the predetermined angle θ.

When the ratio of the thickness D11 is equal to or smaller than the lower limit value, the shape becomes close to a straight shape, and a predetermined grip center point angle cannot be obtained. Even if the angle is given, the thickness D12 becomes larger than necessary at the root of the neck portion 13, and the effect as a thin neck portion is reduced. When the thickness D11 exceeds the upper limit value, since the bending of the neck portion 13 starts at an early stage, it is difficult to impart an appropriate grip center point angle, and the intra-oral operability is also reduced.

(2) The variation (D11 (10)/D11 (20)) of the thickness D11 between the position 20mm away from the tip end side of the ridge line K2 and the position 10mm away from the tip end side of the ridge line K2 is 1.2 or more, preferably 1.4 or more, and more preferably 1.7 or more. The upper limit of the variation (D11 (10)/D11 (20)) of the thickness D11 is 2.5.

When the variation (D11 (10)/D11 (20)) of the thickness D11 between the position 20mm away from the tip end side of the ridge line K2 and the position 10mm away from the tip end side of the ridge line K2 is smaller than the lower limit value, the straight shape continues to the root of the neck portion 13, and therefore the predetermined grip center point angle cannot be obtained. When the change (D11 (10)/D11 (20)) in the thickness D11 between the position 20mm away from the tip end side of the ridge line K2 and the position 10mm away from the tip end side of the ridge line K2 exceeds the upper limit value, the bending of the neck portion 13 starts at an early stage, and therefore it is difficult to impart an appropriate grip center point angle, and the intra-oral operability is also reduced.

The change in D11 between the position 10mm away from the tip of the ridge line K2 and the position 0mm is 1.4 or more, preferably 1.8 or more, and more preferably 1.9 or more. The upper limit of the change in D11 between the position at the tip side of 10mm and the position at 0mm is 3.0.

When the change in D11 between the position of the ridge line K2 at a distance of 10mm and the position of 0mm is smaller than the lower limit value, the straight shape continues until the root of the neck portion 13, and therefore the predetermined grip center point angle cannot be obtained. When the change in D11 between the position of the ridge line K2 at a distance of 10mm and the position of 0mm exceeds the upper limit value, bending of the neck portion 13 starts at an early stage, and therefore it is difficult to impart an appropriate grip center point angle, and the intra-oral operability is also reduced.

The change rate (D12 (20)/D12 (10)) of the thickness D12 between the position 20mm away from the tip end side of the ridge line K2 and the position 10mm away from the tip end side of the ridge line K2 is 1.3 or more, preferably 1.4 or more.

The thickness D12 at a position 10mm away from the tip end side of the ridge line K2 and a position 0mm varies by 1.3 or more, preferably 1.4 or more.

When the lower limit value is less than or equal to the lower limit value, the lower side is not bent in accordance with the shape change of the upper side, and the finger contact portion becomes unnecessarily thick, making it difficult to hold. The upper limit value is not particularly limited, but preferably does not exceed the upper variation in the same section.

The thickness (D11 (0) +d12 (0)) at the position of the ridge line K2 is preferably 7mm or more and 15mm or less, more preferably 8.4mm or more and 13.5mm or less, and still more preferably 8.8mm or more and 10mm or less.

[ distance a between the base end of the head and the tip end of the finger contact portion ]

The greater the distance a from the base end of the head 12 (boundary position K1 between the neck 13 and the head 12) to the tip end of the finger contact portion 19 (boundary K2 between the neck 13 and the handle 14), the deeper the bristle part 11 can reach the inside of the oral cavity, and the greater the cleaning effect to each corner in the oral cavity, but conversely, the greater the deflection of the neck 13. On the other hand, the smaller the distance a, the smaller the deflection of the neck portion 13 can be made, but the more difficult the hair-planting portion 11 becomes to reach deep in the oral cavity. Therefore, the distance a is also determined by the conditions such as the constituent material of the handle body 15 and the flexural modulus, but may be set to be, for example, about 25mm to 70mm.

[ angle of grip center θ ]

Hereinafter, an angle θ formed by the straight line N connecting the center point G2 in the thickness direction of the handle portion 14 at the grip center position G1 of the toothbrush 1 and the center point S2 in the thickness direction of the head portion 12 at the center position S1 of the bristle part 11 and the plane P constituting the bristle surface 12a is referred to as a grip center point angle θ.

When the grip center angle θ is excessively large, the difference between the extending direction of the handle portion 14 and the extending direction of the head portion 12 becomes large, and the operability of the handle portion 14 is lowered. When the grip center angle θ is too small, the shape of the grip body 15 becomes a straight line, and the original effect of the present embodiment cannot be obtained. In consideration of this, the grip center point angle θ may be set to 5.0 degrees or more and 10.0 degrees or less. The grip center angle θ is more preferably 6.0 degrees or more and 8.0 degrees or less.

[ grip center height h ]

The distance between the center point G2 in the thickness direction of the grip portion 14 at the grip center position G1 of the toothbrush 1 and the plane P constituting the bristle surface 12a is defined as the grip center point height h.

The grip center point height h may be set to 6.0mm or more and 15.5mm or less. The lower limit of the grip center height h is preferably 7.0mm or more, and the upper limit thereof is preferably 15.0mm or less, more preferably 14.5mm or less, still more preferably 13.5mm or less, more preferably 12.0mm or less, particularly preferably 11.0mm or less. The upper and lower ranges are preferably 7.0mm to 15.0mm, more preferably 7.0mm to 14.5mm, still more preferably 7.0mm to 13.5mm, still more preferably 7.0mm to 12.0mm, particularly preferably 7.0mm to 11.0mm.

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 modified and implemented as appropriate without departing from the gist thereof.

Toothbrushes of examples 1 to 10 and comparative examples 1 to 4 were manufactured by injection molding according to the specifications shown in table 1. In the toothbrush, the width, length, thickness and shape of the handle part are all the same. The various resins shown in table 1 were injection molded to obtain an integrally molded article of the head, neck and grip shown in fig. 1 and 2. The arrangement of the implanted holes is 3 holes by 1 column, 4 holes by 6 columns and 3 holes by 1 column from the front end of the head toward the neck. The width and length of the head are shown in table 1. A toothbrush was manufactured by implanting tufts of tapered bristles (7.5 mil) formed of monofilaments made of PBT into the head through flat wire implants Mao Lai.

As evaluation items of each sample, 2 items of intra-oral operability and handle operability are exemplified. Regarding the intraoral operability, "very excellent" is indicated as "very good", "excellent" is indicated as "o", "slight difference" is indicated as "Δ", and "very poor" is indicated as "x". Similarly, regarding the handleability, "very excellent" is indicated as "very good", "excellent" is indicated as "o", "slight difference" is indicated as "Δ", and "very poor" is indicated as "x".

TABLE 1

As shown in table 1, the grip center angle θ and the grip center height h of the toothbrush of comparative example 1 were outside the numerical range of the present invention. That is, the toothbrush of comparative example 1 had a handle body having a shape relatively close to a straight line. Therefore, the toothbrush of comparative example 1 was confirmed to have poor in-oral operability and grip operability. Further, the toothbrush of comparative example 2 had a head thickness t, a minimum width W1 of the neck, and a minimum thickness D1 of the neck outside the numerical range of the present invention. Therefore, the toothbrush of comparative example 2 was confirmed to have poor intraoral operability. Further, the toothbrush of comparative example 3 was confirmed to have poor intraoral operability and grip operability when the grip center point height h was outside the numerical range of the present invention. The toothbrush of comparative example 4 had a grip center angle θ and a grip center height h outside the numerical range of the present invention, and was confirmed to have poor intraoral operability and grip operability.

In contrast, all of the parameters of the head thickness t, the minimum width W1 of the neck, the minimum thickness D1 of the neck, the grip center angle θ, and the grip center height h of the toothbrushes of examples 1 to 10 fall within the numerical range of the present invention. Thus, it has been confirmed that even if the neck portion is deflected, both the intraoral operability and the handle operability are excellent.

In general, flat wire type hair implantation is used, and pressure is applied to the head portion by driving the flat wire. When the head is thin, on the one hand, strength against deformation at the time of application of force is low, and on the other hand, when the neck is thick and strong, pressure at the time of brushing teeth is concentrated on the head, and deflection of the head becomes large, and there is a case where usability is lowered. In this case, as in the toothbrush 1 of the present embodiment, by reducing the neck portion, the pressure during brushing can be dispersed from the head portion to the entire neck portion, and the workability can be improved. Therefore, in the case of flat wire type hair planting, the effect of the present invention can be obtained particularly remarkably.

Claims

1. A toothbrush is provided with:

a hair-planting part composed of multiple hair bundles,

The hair-planting surface is provided with a head part of a hair-planting part,

A neck extending from the head,

A handle portion extending from the neck portion,

it is characterized in that the method comprises the steps of,

the thickness of the head is more than 2.0mm and less than 4.0mm,

the minimum width and the minimum thickness of the neck are more than 3.0mm and less than 4.5mm,

the neck part is made of one of polyacetal, polybutylene terephthalate and polyethylene naphthalate,

the neck portion becomes thicker gradually from its front end toward its rear end,

a curved surface which is arranged on the bristle planting surface side at the center position and is in a concave arc contour in a side view is formed on the bristle planting surface side at the rear end side of the neck,

an angle formed by a straight line connecting a center point in a thickness direction of a handle portion at a center position of a toothbrush grip and a center point in a thickness direction of a head portion at a center position of a bristle planting portion and a plane constituting a bristle planting face is 5.0 degrees or more and 8.0 degrees or less,

in the side view, the curved surface is formed on the upper side than the bristle surface of the head, and in the side view, the handle portion is located on the upper side than the bristle surface of the head,

the distance between the central point of the toothbrush handle in the thickness direction and the plane forming the bristle planting surface, namely the height of the handle central point, is 6.0-11.0 mm.

2. The toothbrush of claim 1, wherein the distance a from the base end of the head to the front end of the finger contact means is 53 to 70mm.

3. The toothbrush according to claim 1, wherein the overall length of the toothbrush is 100 to 200mm and the length of the head is 10 to 33mm.

4. The toothbrush according to claim 1, wherein if the thickness of the neck is D, the side view is defined by a plane including the bristle-bearing surface, the thickness of the neck on the upper side than the plane is D11, and the thickness of the neck on the lower side than the plane is D12, D12> D11 in a region between a boundary K1 between the neck and the head and a position 10mm apart from K1.

5. The toothbrush according to claim 1, wherein if the thickness of the neck is D, the side view is defined by a plane including the bristle surface, and the thickness of the neck on the upper side than the plane is D11, the proportion of the thickness D11 on the upper side is 40 to 90% from the boundary K2 on the rear end side of the neck at the position 10mm apart from the front end side.

6. The toothbrush according to claim 1, wherein if the thickness of the neck is D, the side view is defined by a plane including the bristle surface, and the thickness of the neck on the upper side than the plane is D11, the proportion of the thickness D11 on the upper side is 40±10% from the boundary K2 on the rear end side of the neck at the position 20mm apart from the front end side.