CN110267566B - Tooth brush - Google Patents

Abstract

The present invention aims to provide a toothbrush having a high grippability for a handle portion without increasing the cost. The brush holder portion (30) has a first expanded portion (41) having the largest length in the width direction at a first position (P1) in the longitudinal direction, a first narrowed portion (43) having the smallest length at a second position (P2) on the rear end side of the first expanded portion, a second expanded portion (42) having the largest length at a third position (P3) on the rear end side of the first narrowed portion, and a second narrowed portion (44) having the smallest length at a fourth position (P4) on the rear end side of the second expanded portion. When the minimum length of the first constricted part is PW2 and the maximum length of the second expanded part is PW3, PW3 is 15mm or more and 20mm or less, and PW3/PW2 is 1.3 or more and 1.5 or less. When the thickness of the first position is PT1 and the thickness of the third position is PT3, PT3 is 15mm or more and 20mm or less, and PT3/PT1 is 1.7 or more and 2.5 or less.

Description

Tooth brush

Technical Field

The present invention relates to toothbrushes.

The present invention is based on claiming priority from application Japanese patent application No. 2017-147972 at 31/7/2017, the contents of which are incorporated herein by reference.

Background

Conventionally, in order to achieve cleaning from the oral cavity to all corners, the ease of handling in the oral cavity has been focused and the implanted portion has generally been made compact. However, in the case of oral cleaning with a compact bristle part, the cleaning method is required to be skilled, and cleaning is time-consuming. Therefore, a toothbrush having a head (wide head) in which a bristle part is large-sized has been developed, but since the bristle part is designed to be wide, it is difficult for the bristle part to properly reach a cleaning part.

Patent document 1 discloses a wide-head toothbrush having: by devising the types and arrangement of the bristles, a plurality of cleaning parts can be brushed and swept at the same time, and high cleaning performance is achieved.

Prior art documents

Patent document

Patent document 1: JP 2016-209616A

Disclosure of Invention

(problems to be solved by the invention)

However, in the conventional wide-head toothbrush as described above, although the cleaning performance is improved to some extent, the interference of the tufts when the brush is brought into contact with the cleaning portion is large, and therefore, the gripped brush handle portion may shake to hinder stable cleaning. In order to improve the grip performance by improving the grip convenience and the slip resistance of the brush holder portion, it is also conceivable to provide a soft portion such as rubber on the surface of the brush holder portion.

However, in this case, the following problems occur: not only a variety of resins but also a brush holder portion needs to be manufactured by two-color molding or the like, which leads to an increase in cost. Such problems are not limited to a wide head size, but may occur in a compact head size.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a toothbrush having a high grippability of a handle portion without increasing cost.

(means for solving the problems)

According to a first aspect of the present invention, there is provided a toothbrush comprising: a brush head portion which is arranged on the front end side in the long axis direction and is formed by implanting hair bundles on a hair implanting surface; a brush neck part extending from the rear end side of the brush head part; and a brush holder portion extending to a rear end side of the brush neck portion, the brush holder portion including: a first expansion portion which is arranged closer to a rear end side than the brush neck portion, and which expands while continuously changing symmetrically on both sides in a width direction perpendicular to the longitudinal direction and the front direction when viewed from a front side perpendicular to the bristle surface; a first narrowed portion that is disposed closer to the rear end side than the first expanded portion, and that is narrowed while continuously changing symmetrically on both sides in the width direction; a second expanded portion that is arranged closer to the rear end side than the first narrowed portion, and that expands while continuously changing symmetrically on both sides in the width direction; and a second constricted portion that is disposed closer to the rear end side than the second expanded portion and that narrows while changing symmetrically and continuously on both sides in the width direction, wherein the first expanded portion has a maximum length in the width direction at a first position between the brush neck portion and the first constricted portion in the longitudinal direction, the first constricted portion has a minimum length in the width direction at a second position between the first expanded portion and the second expanded portion in the longitudinal direction, the second expanded portion has a maximum length in the width direction at a third position between the first constricted portion and the second constricted portion in the longitudinal direction, the second constricted portion has a minimum length in the width direction at a fourth position closer to the rear end side than the second expanded portion in the longitudinal direction, and the length in the width direction of the first constricted portion at the second position is represented as PW2, And PW3 is 15mm or more and 20mm or less, PW3/PW2 is 1.3 or more and 1.5 or less, when the length in the width direction of the second expanded portion at the third position is PW3, PT3 is 15mm or more and 20mm or less, and PT3/PT1 is 1.7 or more and 2.5 or less, when the thickness in the front direction at the first position is PT1 and the thickness in the front direction at the third position is PT 3.

In the toothbrush according to the above aspect of the invention, the outline of each of the first expanded portion, the first narrowed portion, the second expanded portion, and the second narrowed portion in the front view is formed by a curved line circumscribing the expanded portion or the narrowed portion adjacent to each other in the longitudinal direction.

In the toothbrush according to the aspect of the present invention, the handle portion at the first position has a flat shape whose length in the width direction is larger than the thickness in the front direction, and the handle portion at the third position has a substantially circular cross-sectional shape.

In the toothbrush according to the above aspect of the present invention, at least one of the front surface side and the back surface side of the handle portion at the first position has a groove portion.

In the toothbrush according to the above aspect of the present invention, the groove is formed in a ring shape.

In the toothbrush according to the aspect of the present invention, the maximum length of the brush head portion in the width direction is 13mm or more.

(effect of the invention)

In the present invention, a toothbrush having a high grippability for the handle portion without causing an increase in cost can be provided.

Drawings

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

Fig. 2 is a side view of the toothbrush 1.

Fig. 3 is a rear view of the toothbrush 1.

Fig. 4 is a cross-sectional view of handle portion 30 cut at first position P1.

Fig. 5 is an enlarged side view of the first position P1 in fig. 2.

Fig. 6 is a cross-sectional view of handle portion 30 cut at third position P3.

Fig. 7 is an enlarged side view of the rear end of the handle portion 30 including the fourth position P4.

Detailed Description

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

In the present embodiment, a wide-head toothbrush in which the width of the head portion is increased will be used as an example for the description.

The following embodiments are illustrative of one aspect of the present invention, and are not intended to limit the present invention, and may be arbitrarily modified within the scope of the technical idea of the present invention. In the drawings below, the scale, the number, and the like of each structure are different from those of an actual structure in order to facilitate understanding of each structure.

Fig. 1 is a front view of the toothbrush 1. Fig. 2 is a side view of the toothbrush 1. Fig. 3 is a rear view of the toothbrush 1.

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

The brush head portion 10 has a bristle surface 11 on one side in the thickness direction. In the thickness direction, the side of the flocked surface 11 is referred to as the front surface side in the front direction, the opposite side to the flocked surface 11 is referred to as the back surface side, and the direction perpendicular to the front direction and the longitudinal direction is referred to as the width direction. In the following description, the thickness in the front direction is simply referred to as "thickness". A plurality of implantation holes 12 are formed in the implantation surface 11. In the bristle-implanting hole 12, a bundle of bristles (not shown) is implanted.

The brushhead portion 10 is of a wide head format with a wide width. The maximum width W1 of the brush head portion 10 is 13mm or more and 16mm or less. The length of the brush head portion 10 is not particularly limited, and is preferably 10mm or more and 33mm or less, for example. When the length of the head portion 10 is equal to or greater than the lower limit, a sufficient area for implanting the hair bundle can be secured, and when the length is equal to or less than the upper limit, the operability in the oral cavity is further improved.

Among the plurality of implant holes 12, the distance between the implant hole 12 of the head portion 10 located at the most front end side and the front end of the head portion 10 is set to be equal to the distance between the implant hole 12 of the head portion 10 located at the most rear end side and the rear end of the head portion 10. In other words, when the distance between the bristle-implanted hole 12 located on the most front end side of the head portion 10 and the front end of the head portion 10 is d, the boundary position between the head portion 10 and the neck portion 20 is a position away from the rear end side by an equal distance, i.e., the distance d, from the bristle-implanted hole 12 located on the most rear end side of the head portion 10.

The thickness of the brush head portion 10 can be determined in consideration of the material of the brush holder 2, and is preferably 2.0mm or more and 6.0mm or less, and more preferably 3.0mm or more and 5.0mm or less. If the thickness is not less than the lower limit, the strength of the head portion 10 is further improved, and if the thickness is not more than the upper limit, not only the reaching ability to the depth of the molar teeth is improved, but also the operability in the oral cavity is further improved.

The length of the brush neck portion 20 is preferably 40mm to 70mm in order to bring the brush neck portion 20 into contact with the lip when the brush head portion 10 is inserted into the oral cavity.

The minimum width and the minimum thickness of the brush neck portion 20 are preferably 3.0mm or more and 6.0mm or less, for example. If the lower limit value is not less than the lower limit value, the strength of the brush neck portion 20 is further improved, and if the upper limit value is not more than the upper limit value, the lip is easily closed, and the reach to the molar teeth is improved, and the operability in the oral cavity is further improved.

As described later, although the boundary between the neck portion 20 and the stem portion 30 includes a boundary 31 on the front side and a boundary 32 on the back side (see fig. 5), the boundary 31 on the front side is used at the position on the rear end side when the length of the neck portion 20 is designed.

As shown in fig. 2, both the front side and the back side of the brush neck portion 20 extend substantially parallel to the bristle surface 11. The brush neck portion 20 has a curved contour 21 having a circular arc shape with a polarization center on the front side in side view and gradually heading upward (front side) toward the rear end side. The back surface side of the brush neck portion 20 has a curved contour 22 having a circular arc shape with a polarization center on the back surface side in side view and gradually facing downward (back surface side) as it goes to the rear end side.

As shown in the front view of fig. 1 and the rear view of fig. 3, the brush holder portion 30 includes: a first expansion portion 41 and a second expansion portion 42 whose length in the width direction changes continuously and symmetrically on both sides to expand; a first narrowing portion 43 and a second narrowing portion 44 which are narrowed while continuously changing the length in the width direction symmetrically on both sides; and a through hole 46 disposed near the rear end. The first expanded portion 41, the first narrowed portion 43, the second expanded portion 42, and the second narrowed portion 44 are arranged in this order from the distal end side in the longitudinal direction. Further, a groove 45A is formed on the front side of the handle portion 30, and a groove 45B is formed on the rear side of the handle portion 30.

At the first position P1 on the distal end side in the longitudinal direction, the length of the first expanded portion 41 in the width direction is largest. The first position P1 is a position at which the width-directional length of the first expanded portion 41 is the greatest between the brush neck portion 20 and the first narrowed portion 43 in the longitudinal direction. The length of the first narrowing portion 43 in the width direction is smallest at a second position P2 located on the rear end side of the first position P1 in the longitudinal direction. The second position P2 is a position at which the length of the first constricted portion 43 in the width direction between the first expanded portion 41 and the second expanded portion 42 in the longitudinal direction is smallest. The second inflation section 42 has the largest length in the width direction at the third position P3 located on the rear end side of the second position P2 in the longitudinal direction. The third position P3 is a position at which the length of the second expanded portion 42 in the width direction is maximum between the first constricted portion 43 and the second constricted portion 44 in the longitudinal direction. The second narrowing portion 44 has the smallest length in the width direction at a fourth position P4 located on the rear end side of the third position P3 in the longitudinal direction. The fourth position P4 is a position where the length in the width direction of the second narrowing portion 44 is smallest on the rear end side in the long axis direction than the third position P3. That is, the position is changed from a curve or straight line forming both edges of the narrowed width at the third position P3 to a curve or straight line of the widened width, or a straight line of the same width.

The outline of each of the first expanded portion 41, the first narrowed portion 43, the second expanded portion 42, and the second narrowed portion 44 in the front view is formed as a smooth curve circumscribing the adjacent expanded portion or narrowed portion in the longitudinal direction.

Specifically, the first expanded portion 41 has a curved contour C1 in the shape of an arc having a center of curvature on the widthwise central side in front view. The first narrowed portion 43 has a curved contour C2 in the shape of a circular arc having a center of curvature on the outer side in the width direction in front view. The second expanded portion 42 has a curved contour C3 in the shape of an arc having a center of curvature on the widthwise central side in front view. The second narrowed portion 44 has a curved contour C4 in the shape of a circular arc having a center of curvature on the widthwise outer side in front view. The curved contours C1 to C4 each circumscribe adjacent curved contours in the longitudinal direction.

When the length in the width direction of first expanded portion 41 (the width at first position P1) is PW1, the length in the width direction of first narrowed portion 43 (the width at second position P2) is PW2, the length in the width direction of second expanded portion 42 (the width at third position P3) is PW3, and the length in the width direction of second narrowed portion 44 (the width at fourth position P4) is PW4, brush holder portion 30 satisfies the following relationships (1) and (2), respectively.

PW3＞PW1＞PW2…(1)

PW3＞PW4＞PW2…(2)

The width PW1 at the first position P1 is preferably 14mm or more and 17mm or less.

The width PW2 at the second position P2 is preferably 11mm or more and 14mm or less.

The width PW3 at the third position P3 is preferably 15mm or more and 20mm or less.

The width PW4 at the fourth position P4 is preferably 12.5mm or more and 15.5mm or less.

The difference in width between the first position P1 and the second position P2 (PW 1-PW 2) is preferably 2.5mm or more and 3.5mm or less.

The difference in width between the third position P3 and the second position P2 (PW 3-PW 2) is preferably 4mm to 5.5 mm.

The difference in width between the fourth position P4 and the second position P2 (PW 4-PW 2) is preferably 0.5mm to 1.5 mm.

PW3/PW2 is preferably 1.3 to 1.5 inclusive.

As shown in fig. 2, the brush holder portion 30 includes: a circular arc-shaped curved contour C11 disposed at the first position P1 and having a curvature center on the front side in a side view; a circular arc-shaped curved contour C12 disposed at the second position P2 and having a curvature center on the front side in a side view; an arc-shaped curved contour C13 disposed at the third position P3 and having a center of curvature on the back side in side view; an arc-shaped curved contour C14 disposed at the fourth position P4 and having a curvature center on the front side in a side view; and a curved contour C15 in the shape of an arc circumscribing the curved contours C12 and C13, respectively, and having a center of curvature on the back surface side in side view. The curved line profiles C12 to C15 are circumscribed with the curved line profiles adjacent in the long axis direction.

As shown in fig. 2, the brush holder portion 30 has, on the back side thereof: an arc-shaped curved contour C21 disposed at the first position P1 and having a center of curvature on the back side in side view; a circular arc-shaped curved contour C22 disposed at the second position P2 and having a curvature center on the front side in a side view; a circular arc-shaped curved contour C23 disposed at the third position P3 and having a curvature center on the front side in a side view; an arc-shaped curved contour C24 disposed at the fourth position P4 and having a center of curvature on the back side in side view; and a curved contour C25 in the shape of an arc that circumscribes the curved contours C22 and C23, respectively, and has a center of curvature on the front side in side view. The curved line profiles C22 to C25 are circumscribed with the curved line profiles adjacent in the long axis direction.

When the thickness at the first position P1 is PT1, the thickness at the second position P2 is PT2, the thickness at the third position P3 is PT3, and the thickness at the fourth position P4 is PT4, the stem portion 30 satisfies the following relationships (3) and (4), respectively.

PT3＞PT2＞PT1…(3)

PT3＞PT4＞PT1…(4)

The thickness PT1 at the first position P1 is preferably 6.5mm or more and 9mm or less.

The thickness PT2 at the second position P2 is preferably 9mm or more and 11mm or less.

The thickness PT3 at the third position P3 is preferably 15mm or more and 20mm or less.

The thickness PT4 at the fourth position P4 is preferably 10mm or more and 13mm or less.

The difference in thickness between the first position P1 and the second position P2 (PT 2-PT 1) is preferably 1.5mm to 3.0 mm.

The difference in thickness between the first position P1 and the third position P3 (PT 3-PT 1) is preferably 5.5mm to 9 mm.

The difference in thickness between the first position P1 and the fourth position P4 (PT 4-PT 1) is preferably 2.5mm or more and 4.5mm or less.

PT3/PT1 is preferably 1.7 to 2.5 inclusive.

The distance between the first position P1 and the third position P3 is preferably 30mm or more and 60mm or less. When the distance between the first position P1 and the third position P3 is less than the lower limit value, the distance between the first position P1 and the third position P3 becomes shorter when the brush holder portion 30 is held, and the distal end of the thumb that contacts the front side of the second position P2 and the index finger that contacts the circumferential direction of the second position P2 become closer, so that not only is there a possibility that the assist function when a load is applied to the brush head portion 10 during cleaning lowered, but it becomes difficult to tactually distinguish the first position P1 from the third position P3. When the distance between the first position P1 and the third position P3 exceeds the above upper limit value, the distance between the first position P1 and the third position P3 becomes longer when the brush holder portion 30 is held, and there is a possibility that the finger rest portion, which is the distal end of the thumb on the front side of the first position P1, is difficult to hold in the third position P3 with the middle finger and the ring finger in contact with the circumferential direction.

Fig. 4 is a cross-sectional view of handle portion 30 cut at first position P1.

As shown in fig. 4, the cross-sectional shape of the handle portion 30 (first expanded portion 41) at the first position P1 is a flat shape having a length in the width direction larger than the thickness. The front side of the brush holder portion 30 is provided with a circular groove portion 45A formed in a ring shape in front view with the center in the width direction at the first position as the center. On the back surface side of the brush holder portion 30, a circular groove portion 45B is provided in a front view, which is formed in a ring shape with the center in the width direction at the first position as the center.

As shown in fig. 4, the front side of the stem portion 30 has an arc-shaped curved contour C31 having a center of curvature on the rear side with respect to the width direction. The curved contour C31 has grooves 45A on both sides thereof, and the height T1 is formed with a low step of 0.5 to 1.5 mm.

Similarly, the rear surface side of the brush holder portion 30 has a curved contour C32 in the shape of an arc having a center of curvature on the front surface side with respect to the width direction. The curved contour C32 has grooves 45B on both sides thereof, and the height T2 is formed with a low step of 0.5 to 1.5 mm.

Fig. 5 is an enlarged side view of the first position P1 in fig. 2.

The boundary 31 between the neck portion 20 and the stem portion 30 on the front side is formed by a ridge line at the intersection of the curved contour 21 arranged on the front end side of the boundary 31 and the curved contour C11 arranged on the rear end side of the boundary 31, as viewed from the side. The position in the front direction of the boundary 31, i.e., the position at which the curved contour C11 intersects the curved contour 21, is located on the front side of the position at which the curved contour C11 intersects the curved contour C12. Therefore, a curved surface that projects more steeply than the rear end side of the first position P1 is formed on the front end side of the first position P1 on the front surface side.

The height T3 of the groove 45A is formed with a step of 0.5 to 1.5mm on the front end side in the longitudinal direction.

On the rear end side in the longitudinal direction, the height T4 of the groove 45A is formed with a step of 0.5 to 1.5 mm.

Similarly, a boundary 32 between the neck portion 20 and the stem portion 30 on the back side is formed by a ridge line at a position where the curved contour 22 disposed on the front end side of the boundary 32 and the curved contour C21 disposed on the rear end side of the boundary 32 intersect with each other in a side view. The front position of the boundary 32, i.e., the position at which the curved contour C21 intersects the curved contour 22, is located on the back surface side of the position at which the curved contour C21 intersects the curved contour C22. Therefore, a curved surface that projects more steeply than the rear end side of the first position P1 is formed on the front end side of the first position P1 on the back surface side.

The height T5 of the groove 45B is formed with a step of 0.5 to 1.5mm on the front end side in the longitudinal direction.

The rear end side in the longitudinal direction of the groove 45B has a height T6 of 0.5 to 1.5 mm.

Fig. 6 is a cross-sectional view of handle portion 30 cut at third position P3.

As shown in fig. 6, the cross-sectional shape of the handle portion 30 at the third position P3 is substantially circular. The maximum diameter of the handle portion 30 at the third position P3 is preferably 15mm or more and 20mm or less. When the maximum diameter of the brush holder portion 30 is smaller than the lower limit value, the grip area is small and the middle finger and ring finger cannot sufficiently abut each other when the vicinity of the third position P3 is gripped by a palm grip method (palm grip), which may result in slippage and reduced grip performance. When the maximum diameter of the handle portion 30 is higher than the upper limit value, the circumferential length becomes larger when the periphery of the third position P3 is grasped in a palm grip manner, and the grasping becomes difficult.

Fig. 7 is an enlarged side view of the rear end of the handle portion 30 including the fourth position P4.

As shown in fig. 7, a through hole 46 penetrating in the front direction is formed near the rear end of the stem portion 30. As shown in fig. 1 and 7, a groove 47 extending from the through hole 46 toward the front end side is disposed on the front side of the stem 30. The groove 47 has a semicircular cross-sectional shape with a depth of about 1mm, for example.

Similarly, a groove portion 49 extending toward the front end side is disposed on the back surface side of the brush holder portion 30 from the through hole 46 to the fourth position P4. The groove 49 has a semicircular cross-sectional shape with a depth of about 1mm, for example.

The length of the brush holder 2 is not particularly limited, but is, for example, 100 to 200 mm. The brush holder body 2 is integrally formed in a long shape as a whole, and is obtained by injection molding using, for example, resin as a material. Examples of the resin constituting the brush holder body 2 include resins having a flexural modulus of elasticity (JIS7171) of 1000MPa to 2200MPa, for example, polypropylene resins (PP), polyamide fiber resins (POM), polystyrene resins (PS), polyethylene terephthalate resins (PET), polybutylene terephthalate resins (PBT), acrylonitrile butadiene styrene resins (ABS), polyarylate resins, polycarbonate resins, and acrylonitrile styrene resins (AS). Among these resins, polypropylene resins are preferred as general-purpose resins from the viewpoint of cost.

The tufts are formed by binding a plurality of bristles. The length (hair length) from the hair-planted surface 11 to the tip of the hair bundle can be determined in consideration of the stiffness of the hair desired for the hair bundle, and is set to 6 to 14mm, for example. All tufts may have the same or different lengths.

The thickness of the tufts (tuft diameter) can be determined in consideration of the stiffness of the bristles sought by the tufts, and is set to 1 to 3mm, for example. All of the tufts may have either the same tuft diameter or different tuft diameters from one another.

Examples of the bristles constituting the hair bundle include bristles (tapered bristles) having sharpened tips, which gradually decrease in diameter as they go to the tips, and bristles (straight bristles) having substantially the same diameter from the bristle surface 11 toward the tips. The straight hair includes straight hair having a hair tip in a plane substantially parallel to the hair-planted surface 11, or straight hair having a hair tip curved in a hemispherical shape.

Examples of the material of the wool include polyamides such as 6-12 nylon (6-12NY) and 6-10 nylon (6-10NY), polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN) and polybutylene naphthalate (PBN), polyolefins such as polypropylene (PP), polyolefin-based elastomers and styrene-based elastomers. As to these resin materials, can use alone 1, or more than 2 kinds of combination use. Further, as the bristles, there are exemplified polyester bristles having a multiple core structure having a core portion and at least 1 or more layers of sheath portions provided outside the core portion.

The cross-sectional shape of the brush is not particularly limited, and may be circular, oval, polygonal, star-shaped, clover-shaped, tetrafoil-shaped, or the like. The cross-sectional shapes of all the bristles may be the same or different.

The thickness of the brush is determined by considering the material, and is, for example, 6 to 9 mils (1 mil: 1/1000 inch: 0.025mm) when the cross section is circular. Further, it is also possible to use a plurality of bristles having different thicknesses in any combination, considering the feeling of use, brushing, cleaning effect, durability, and the like.

The handle 2 of the toothbrush 1 configured as described above is molded by, for example, injection molding using a mold having a space (cavity) of a shape and size corresponding to the handle 2. A gate for injecting the resin melted in the mold is disposed at, for example, the rear end portion of the brush holder body 2. The molten resin injected from the gate fills the cavity of the mold, and is cooled and taken out of the mold, thereby completing the manufacturing.

In some cases, the brush handle 2 is used for injection molding after a glossy material such as pearl pigment is mixed and kneaded with a resin for the purpose of improving texture and appearance and creating a high-grade feeling. When the resin containing such a glossy material flows in the mold, the glossy material is oriented, and therefore, in the head portion 10 particularly at the flow end, the jet flow (jet), flow marks, and weld lines are more noticeable in appearance than in the case where the glossy material is not used.

In the brush holder body 2 of the present embodiment, the through hole 46 is disposed at a position closest to the gate 50, and therefore the flow of the molten resin injected from the gate 50 is controlled by the shaft-shaped mold forming the through hole 46, and the speed and the size of the flow path can be controlled. Therefore, the jet flow and the flow mark are less noticeable in appearance. Further, by arranging the groove portions 47 and 49 extending toward the distal end side from the through hole 46 to the fourth position P4, the weld line generated by branching and merging of the molten resin through the through hole 46 overlaps with the groove portions 47 and 49, and therefore, the appearance is less noticeable.

Next, an operation when the handle portion 30 of the toothbrush 1 is held in a palm grip manner will be described.

(first position P1)

The front side of the first position P1 of the brush holder portion 30 is a finger rest portion on the brush neck portion 20 side and is abutted by the tip of the thumb. The back side of the first position P1 is abutted by the middle segment of the index finger. Thus, the brush holder portion 30 is held so as to be sandwiched from the front side and the back side at the first position P1. At this time, since the groove 45A is disposed on the front side of the first position P1 and the groove 45B is disposed on the back side of the first position P1, the finger placement portion can be made clear from the touch. Further, since the grooves 45A and 45B are formed in a circular shape, they are less likely to slip when the finger is moved in a movement in a plane substantially parallel to the flocked surface 11 including the width direction and the longitudinal direction.

Further, since the brush holder portion 30 has a flat cross section at the first position P1, the brush holder portion 30 can be easily urged to be held stably by being in contact with the thumb on the front side and the index finger on the back side in a wide area at the first position P1. Therefore, the force applied to the brush holder portion 30 at the first position P1 close to the brush head portion 10 is easily transmitted to the brush head portion 10, so that the operability is improved, and the implanted surface can be favorably brought into contact with the teeth.

(second position P2)

The second position P2 functions as an auxiliary portion on the brush neck portion 20 side for distinguishing the first position P1 and the third position P3 when the brush holder portion 30 is held. When the handle portion 30 is held by palm grip, the tip of the thumb comes into contact with the front side of the second position P2, and the index finger comes into contact with the circumferential direction of the second position P2, whereby the handle portion is held by being sandwiched from the front side and the back side at the first position P1, and the middle portion of the handle portion 30 held by palm grip, the middle finger, and the ring finger can be held in an auxiliary manner at the third position P3. Since the first narrowed portion 43 is arranged in front view at the second position P2, the index finger can easily come into contact with the circumferential direction. Further, since the first narrowed portion 43 is disposed, the shape difference between the first position P1 and the third position P3 can be visually recognized when the handle portion 30 is gripped, and the handle portion can be guided to be inserted and gripped naturally and easily.

(third position P3)

The third position P3 is provided with the second expansion portion 42 having the largest width direction, and functions as a grip stabilizer. When the brush holder portion 30 is held in the palm grip manner, the palm, the middle finger, and the ring finger are in contact with the peripheral direction of the third position P3. The brush holder portion 30 has a substantially circular cross-sectional shape at the third position P3, and the maximum length PW3 and the maximum thickness PT3 in the width direction are the largest as compared with the other positions P1, P2, and P4, and therefore can be stably held in a hand being held.

(fourth position P4)

When the brush holder portion 30 is held in a palm grip, the region up to the rear end portion including the fourth position P4 functions as an auxiliary portion when the palm, middle finger, and ring finger hold the third position P3. When the brush handle portion 30 is held in a palm grip manner, the ring finger, the little finger, and the hill of the palm abut against the peripheral direction of the fourth position P4. Since the maximum widths PW4 and PT4 at the fourth position P4 are smaller than the maximum widths PW3 and PT3 at the third position P3, ring fingers and little fingers shorter than the middle finger can stably abut against the peripheral direction of the fourth position P4.

In the brush holder portion 30, the lengths in the width direction at the first position P1 to the fourth position P4 satisfy the above-described relationships (1) and (2), respectively, and therefore, the thumb on the front side and the index finger on the back side are brought into contact with the finger placement portion at the first position P1 over a wide area in a state where the thumb and the index finger are not easily slid, and the palm, the middle finger, and the ring finger are brought into contact with the peripheral direction at the second expanded portion 42 at the third position P3 formed with the largest diameter, whereby the hand can be placed in the hand to be held stably. Further, since the minimum width PW2 of the first narrowed portion 43 is smaller than the maximum width PW1 of the first expanded portion 41 and the maximum width PW3 of the second expanded portion 42, the intermediate portion of the brush holder 30 held at the first position P1 and the third position P3 can be held supplementarily, and the operability during cleaning is improved by stable holding. Further, since the minimum width PW4 of the rear end portion including the second narrowed portion 44 is larger than the minimum width PW2 of the first narrowed portion 43, the holding of the second expanded portion 42 can be favorably assisted from the rear end side, and the gripping property can be further stabilized. The above-described effects can be further obtained by adjusting PW3/PW2 to 1.3 or more and 1.5 or less.

In the brush holder portion 30, the thicknesses at the first position P1 to the fourth position P4 satisfy the above relationships (3) and (4), respectively, and the thickness of the first position P1 serving as the finger placement portion is set to be the smallest, so that the first position P1 can be easily and strongly held from the front side and the back side. Therefore, the force applied to the brush holder portion 30 at the position close to the brush head portion 10 is easily transmitted to the brush head portion 10, so that the operability is improved and the implanted surface can be favorably brought into contact with the teeth. Since the first position P1 is thin, a steeply projecting curved surface is formed between the boundaries 31 and 32 between the neck portion 20 and the stem portion 30 and the first position P1. Therefore, the thumb and the index finger abutting on the finger placement portion are fitted to the curved surface at the rear end side, and the gripped brush holder portion 30 can be prevented from wobbling in the longitudinal direction. The effects described above are further obtained by setting PT3/PT1 to 1.7 or more and 2.5 or less.

In the brush holder portion 30, the curved contour C1 of the first swelling portion 41, the curved contour C2 of the first narrowed portion 43, the curved contour C3 of the second swelling portion 42, and the curved contour C4 of the second narrowed portion 44 are circumscribed with the curved contours adjacent in the longitudinal direction, the curved contours C11, C12, C13, C14, and C15 on the front surface side are circumscribed with the curved contours adjacent in the longitudinal direction, and the curved contours C21, C22, C23, C24, and C25 on the rear surface side are circumscribed with the curved contours adjacent in the longitudinal direction, so that the respective contours are smoothly connected. Therefore, the handle part 30 can be adapted to various holding modes, and the toothbrush 1 having excellent operability and versatility can be realized.

As described above, in the toothbrush 1 according to the present embodiment, by appropriately setting the shape and size of the handle portion 30, the toothbrush 1 having high grippability to the handle portion 30 and high operability in cleaning can be obtained without increasing the cost due to the use of a soft portion or the like. In particular, in the present embodiment, the configuration of the head portion 10 having a wide head width makes it possible to provide the brush portion 30 having a high gripping performance suitable for being put into the hand even when the brush portion is shaken due to a large interference of the bristle bundle when the bristle portion is brought into contact with the cleaning portion and it is difficult to appropriately reach the cleaning portion, and thus the operability is good and the bristle portion can be brought into good contact with the teeth.

Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it is needless to say that the present invention is not limited to these examples. The shapes, combinations, and the like of the respective constituent members shown in the above examples are merely examples, and various modifications can be made in accordance with design requirements and the like within a scope not departing from the gist of the present invention.

For example, although the above embodiment illustrates the configuration in which the groove portions 45A and 45B are provided on both the front side and the back side of the first position P1, the configuration may be such that the groove portions are provided only on the front side or the back side.

Although the above embodiment illustrates the configuration using the brush head portion 10 having a wide head size, the present invention is not limited to the wide head size, and can be applied to a brush head portion having a normal type or a compact size.

Industrial applicability

The invention can be applied to toothbrushes.

(description of reference numerals)

1 … toothbrush, 2 … handle body, 10 … brush head part, 11 … bristle planting surface, 20 … brush neck part, 30 … brush handle part, 41 … first expansion part, 42 … second expansion part, 43 … first narrowing part, 44 … second narrowing part, 45A, 45B … groove part, P1 … first position, P2 … second position, P3 … third position and P4 … fourth position.

Claims (5)

1. A toothbrush, comprising:

a brush head portion which is arranged on the front end side in the long axis direction and is formed by implanting hair bundles on a hair implanting surface;

a brush neck part extending from the rear end side of the brush head part; and

a brush handle part extending from the rear end side of the brush neck part,

the maximum length of the brush head part in the width direction is more than 13mm,

the brush handle portion has:

a first expansion portion which is arranged closer to a rear end side than the brush neck portion, and which expands while continuously changing symmetrically on both sides in the width direction perpendicular to the longitudinal direction and the front direction when viewed from a front side perpendicular to the bristle surface;

a first narrowed portion that is disposed closer to the rear end side than the first expanded portion, and that is narrowed while continuously changing symmetrically on both sides in the width direction;

a second expanded portion that is arranged closer to the rear end side than the first narrowed portion, and that expands while continuously changing symmetrically on both sides in the width direction; and

a second narrowed portion that is disposed closer to the rear end side than the second expanded portion and that is narrowed while continuously changing symmetrically on both sides in the width direction,

a length of the first bulge in the width direction is largest at a first position between the brush neck portion and the first constriction portion in the long axis direction,

a length of the first constricted portion in the width direction is smallest at a second position between the first expanded portion and the second expanded portion in the long axis direction,

a second bulge portion that is formed on the second outer circumferential surface of the second expanded portion, the second bulge portion having a width-directional length that is the largest at a second position between the first and second bulge portions,

a second expanded portion that is located on a rear end side of the second expanded portion in the longitudinal direction, the second narrowed portion having a length in the width direction that is smallest,

when the width-directional length of the first expanded portion at the first position is PW1, the width-directional length of the first narrowed portion at the second position is PW2, and the width-directional length of the second expanded portion at the third position is PW3,

the PW3 is 15mm to 20mm,

PW3/PW2 is 1.3-1.5 inclusive,

when the thickness in the front direction at the first position is PT1, the thickness in the front direction at the second position is PT2, and the thickness in the front direction at the third position is PT3,

the PT3 is 15mm to 20mm,

PT3/PT1 is 1.7-2.5,

PW3＞PW1＞PW2，

PT3 is more than PT2 is more than PT1,

the distance between the first position and the third position is 30mm to 60mm, and the difference between the PT3 and the PT1 is 5.5 to 9 mm.

2. The toothbrush of claim 1,

the first expanded portion, the first narrowed portion, the second expanded portion, and the second narrowed portion are each formed by a curve that circumscribes an adjacent expanded portion or narrowed portion in the long axis direction.

3. The toothbrush of claim 1 or 2,

the cross-sectional shape of the brush holder portion at the first position is a flat shape having a length in the width direction larger than a thickness in the front direction,

the cross-sectional shape of the handle portion at the third position is substantially circular.

4. The toothbrush of claim 1 or 2,

at least one of the front surface side and the back surface side of the brush handle portion at the first position has a groove portion.

5. The toothbrush of claim 4,

the groove portion is formed in a ring shape.

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