TWI906435B - toothbrush - Google Patents

Abstract

This invention provides a toothbrush that improves material recyclability and provides a variety of toothbrushes by configuring the handle and brush head in a way that allows them to be connected/separated, and can suppress the reduction in usability during brushing caused by configuring the handle and brush head in a way that allows them to be connected/separated. The toothbrush 10 has a handle 100, a brush head 200, and a sealing mechanism 300. The handle 100 includes: a handle body 110, forming a hollow internal space 113 and configured for gripping; and a handle neck 120, disposed on the front end side in the long side direction of the handle body and forming a hollow opening 130 communicating with the internal space. The brush head 200 includes: a head. 210, with hair bundles 211; and a brush-side neck portion 220, extending from the head towards the base end in the long direction and forming a connecting portion 230 that can be connected/separated from the mouth. The sealing mechanism 300 maintains the airtightness of the internal space when the mouth and the connecting portion are connected, and the brush-side neck portion has a locking structure that does not form a space connecting the inside and outside of the head.

Description

toothbrush

This invention relates to a toothbrush.

Toothbrush users have vastly different oral conditions and design preferences. However, providing toothbrushes tailored to every individual user significantly deteriorates production efficiency and becomes prohibitively expensive. Furthermore, recent environmental requirements for companies, stemming from microplastic issues and global warming, have placed immense demands on them. Against this backdrop, toothbrushes, being largely composed of resin materials and composed of combinations of various resins, exhibit very poor material recyclability. Therefore, in recent years, there has been a strong desire to establish fundamental measures to improve the material recyclability of toothbrushes.

For example, Patent 1 discloses a toothbrush comprising: a handle having an internal space filled with medication; and a brush portion having bristles embedded therein and configured to be connected/detached from the handle. Inside the brush portion, a flow path is formed that communicates with the internal space of the handle when the handle and brush portion are connected. Furthermore, this flow path communicates with the outside of the brush portion through bristle holes.

The toothbrush in Patent 1 can be deformed by the user gripping and pressing the handle with their fingers, causing the handle to flatten. This flattening deformation causes the medication filling the internal space to move towards the brush head.

Like the toothbrush in Patent 1, where the handle and brush are designed to be connected/separable, the handle and brush can be retrieved separately, or various types of handles and brushes can be selected and combined arbitrarily. Therefore, the toothbrush in Patent 1 is also considered to have high material recyclability and can provide a variety of toothbrush types.

[Existing technical literature]

[Patent Documents]

[Patent Document 1] Japanese Patent Application Publication No. 2005-13375

Regarding the toothbrush in Patent 1, as described above, the handle deforms by being flattened when held by the user, resulting in poor usability during brushing. To address this issue, it is believed that maintaining the airtightness of the internal space of the handle when it is connected to the brush head can prevent the handle from easily deforming when held by the user.

However, regarding the toothbrush of Patent 1, as described above, a flow path communicating with the bristle pores is formed inside the brush head to deliver the medication. Therefore, in the toothbrush of Patent 1, the internal space of the handle cannot be maintained airtight when the brush head and handle are connected. Consequently, when brushing teeth with the toothbrush of Patent 1, it is difficult to avoid a reduction in usability due to easy deformation of the handle.

Furthermore, as with the toothbrush in Patent 1, where the handle and brush head are connected/separable, and the handle is hollow, it is believed that the material recyclability of the toothbrush can be further improved by thinning the handle.

However, in the toothbrush of Patent 1, when the handle is formed with a thin-walled design, the handle becomes more prone to deformation. Therefore, in the toothbrush of Patent 1, if the handle is formed with a thin-walled design, the reduction in usability during brushing becomes significant. Thus, in the toothbrush of Patent 1, it is difficult to significantly improve the material recyclability of the toothbrush while simultaneously suppressing the reduction in usability during brushing.

This invention addresses the aforementioned problems and aims to provide a toothbrush that improves material recyclability and offers a wider variety of toothbrushes by constructing the handle and brush head in a way that allows for connection/separation. Furthermore, it mitigates the reduction in usability during brushing caused by such a detachable design.

The toothbrush of the present invention for achieving the aforementioned purpose has a handle, a brush portion, and a sealing mechanism. The handle includes: a handle body having a hollow internal space and configured for gripping; and a handle neck portion disposed at a front end in the long direction relative to the handle body and having a hollow opening communicating with the internal space. The brush portion includes: a head portion having bristles embedded therein; and a brush neck portion extending from the head portion to a base end in the long direction and having a connecting portion that can be connected/separated from the opening portion. The sealing mechanism maintains the airtightness of the internal space when the opening portion and the connecting portion are connected, and the brush neck portion has a locking structure that does not form a space communicating between the interior and exterior of the head portion.

In the invention with the aforementioned structure, since the handle and head are configured to be connected/separable, material recyclability is improved and a variety of toothbrushes are available. Furthermore, when the handle and head are connected, the airtightness of the internal space of the handle body is maintained, thereby increasing the strength of the handle body. This prevents accidental deformation of the handle body during brushing. Consequently, the reduction in usability associated with deformation of the handle body during brushing is suppressed. Moreover, the toothbrush of the present invention can increase the strength of the handle body, thus allowing for further thinning of the handle body. This further improves material recyclability.

10: Toothbrush

100: Handle

110: Handle Body

111a: Horizontal rib

111b: Ribs

113: Interior Space

120: Handle side and neck area

130: Mouth area

131: Front opening section

132: Anterior face of the mouth

133: Hollow Section

135: First concave part

138: Thick-walled section

140: Shoulders

200: Brush Department

210: Head

211:hair bundle

220: Brush the sides of the neck

230: Connecting Part

231: Insertion Section

232: Front end face of the connector

235:Second convex part

240: Inner cylinder section

242: Base end face of the inner cylinder

250:Outer cylinder part

252: Base end surface of outer cylinder

300: Sealing mechanism

310: Chimeric part

410: Sealing components

420: Lobe structure

430: Adhesive material

D1: Outer diameter of the main body of the stem

D2: Outer diameter of the mouth

c1: The central axis of the toothbrush

g: gap

t1: Wall thickness of the main body of the handle

t2: Wall thickness at the mouth

t3: Wall thickness of the thick-walled section

ta: Wall thickness of the inner cylinder

tb: Wall thickness of the outer cylinder

tc: Distance of the gap

F: Force

L1: Length of the main body of the handle along its long side

L2: Length of the mouth along its long side

r, X1, X2: Arrows (Note: The last part, "r", appears to be a typo and is likely an error.)

Figure 1 is a partial cross-sectional view of the toothbrush according to an embodiment of the present invention.

Figure 2 is an enlarged view of portion 2A enclosed by the dotted line in Figure 1.

Figure 3 is a cross-sectional view along line 3A-3A as indicated by arrow 3A in Figure 2.

Figure 4 is a partial cross-sectional view showing an example of the operating sequence for separating the handle from the brush portion.

Figure 5 is a partial cross-sectional view showing an example of the operating sequence for separating the handle from the brush portion.

Figure 6 is a partial cross-sectional view showing a portion of the toothbrush involved in variant example 1.

Figure 7 is a partial cross-sectional view showing a portion of the toothbrush involved in variant example 2.

Figure 8 is a partial cross-sectional view showing a portion of the toothbrush involved in variant example 2.

Figure 9 is a partial cross-sectional view of the toothbrush involved in variant example 3.

Figure 10 is a partial cross-sectional view of the toothbrush involved in variant example 3.

Figure 11 is a partial cross-sectional view of the toothbrush involved in variant example 3.

Figure 12 is a partial cross-sectional view showing a portion of the toothbrush involved in variant example 4.

Figure 13 is a partial cross-sectional view showing a portion of the toothbrush involved in variant example 4.

Figure 14 is a partial cross-sectional view showing a portion of the toothbrush involved in variant example 4.

The embodiments of the present invention will now be described with reference to the accompanying drawings. Furthermore, the dimensions in the drawings are exaggerated for illustrative purposes and differ from the actual dimensions.

Figures 1-3 are diagrams showing the structure of each part of the toothbrush 10 involved in the embodiment. Figures 4 and 5 are diagrams showing an example of the operating sequence for separating the handle 100 from the brush part 200.

In the figures, arrow X1 indicates the front end of toothbrush 10, and X2 indicates the base end of toothbrush 10. The front and base ends of the handle 100 and brush head 200 are oriented in the same direction as toothbrush 10. The central axis of toothbrush 10 is indicated by a dotted line c1 in the figures.

Toothbrush

As shown in Figure 1, the toothbrush 10 includes a handle 100, a brush head 200, and a sealing mechanism 300.

The toothbrush 10 can be used for cleaning the mouth of a user (natural person). When using the toothbrush 10, the user can connect the handle 100 and the brush head 200 as shown in Figure 1. With the handle 100 and brush head 200 connected, a sealing mechanism 300 is formed in the connection area between the handle 100 and brush head 200.

<Handle>

As shown in Figures 1 and 2, the handle 100 includes: a handle body 110, having a hollow internal space 113 and configured for gripping; and a handle neck portion 120, disposed on the front end side in the longitudinal direction of the handle body 110 and having a hollow opening 130 communicating with the internal space 113.

As shown in Figure 1, the handle body 110 is formed in a hollow manner. Therefore, compared to a handle body with a solid structure including an internal resin-filled structure, the toothbrush 10 can reduce the amount of resin used in its manufacturing.

The handle body 110 has a cylindrical shape with a substantially uniform outer diameter and a substantially uniform cross-sectional area throughout its long length. A recessed portion, facing the front end of the handle body 110, may be formed on the base end face (bottom surface).

The outer diameter D1 of the handle body 110 (refer to Figure 1) can be formed to be, for example, 8.4 mm or more and 50 mm or less. Furthermore, from the viewpoint of reducing the amount of resin in the handle body 110 while maintaining usability for brushing teeth, the outer diameter D1 of the handle body 110 is preferably, for example, 10 mm or more and 40 mm or less, and more preferably 15 mm or more and 30 mm or less.

The outer diameter of a typical toothbrush handle is approximately 10mm. However, considering usability for children, the elderly, or people with disabilities, it is preferable to make the outer diameter of the handle as large as possible. For this reason, appliances with a larger outer diameter are sold that are connected to the toothbrush handle. For example, when manufacturing the handle using conventional injection molding to achieve a larger diameter, the increased amount of resin used in manufacturing leads to problems such as increased weight, sink marks, and longer molding times. On the other hand, when using blow molding to manufacture a handle body 110 with a hollow structure, as described later, it is possible to reduce the amount of resin used in manufacturing while ensuring the strength of the handle body 110. Therefore, it is possible to achieve weight reduction of the handle body 110, shorten molding time, and reduce the appearance associated with the prevention of shrinkage marks. Compared to the handle of a typical toothbrush, the diameter of the handle body 110 can be easily increased. Furthermore, it also achieves the effects of reduced environmental impact and cost reduction due to reduced resin content.

The length L1 of the main body 110 along its long side (refer to Figure 1) can be, for example, 50 mm or more and 150 mm or less. Furthermore, from the viewpoint of preventing the main body 110 from being excessively long and unnecessarily increasing the amount of resin in the main body 110, the length L1 of the main body 110 along its long side is preferably, for example, 70 mm or more and 140 mm or less, and more preferably 90 mm or more and 120 mm or less.

The starting and ending points of the measurement datum for the length L1 of the handle body 110 along its long side are the front end and base end of the handle body 110. The front end of the handle body 110 is located at the boundary between the handle body 110 and the shoulder 140. This boundary is, in the frontal view shown in FIG. 1, the position where the curvature changes with respect to the curve or straight line expanding relative to the outer diameter (width) from the shoulder 140 side to the handle body 110 side, or the position where the angle changes (parallel to the central axis c1). Furthermore, the measurement datum for L1 can also be applied in the various variations described later (e.g., the variation shown in FIG. 9). Furthermore, if the handle body 110 has an asymmetrical shape in the circumferential direction near its front end (as shown in the cross-sectional view in FIG. 2, etc.), the boundary of the front end side, which serves as the reference for the length L1 of the handle body 110 along its long side, can be defined as the position where the measured length L1 becomes the longest.

The wall thickness t1 of the handle body 110 (refer to FIG. 1) can be formed, for example, between 0.25 mm and 2.5 mm. Furthermore, from the viewpoint of effectively reducing the amount of resin in the handle body 110 while preventing excessive reduction in strength, the wall thickness t1 of the handle body 110 is preferably between 0.40 mm and 1.5 mm, and more preferably between 0.50 mm and 1.25 mm. Moreover, the illustrated wall thickness t1 of the handle body 110 is the dimension of the thinnest portion of the wall thickness of the handle body 110.

In this embodiment, the handle 100, including the handle body 110 and the handle neck 120, can be manufactured integrally using a stretch blow molding method, for example. By employing stretch blow molding in the manufacture of the handle 100, compared to using conventional direct blow molding, dimensional accuracy can be improved, and subsequent steps such as burr removal can be omitted. Furthermore, by using stretch blow molding, the high elongation of the preform can be used to increase product strength, thus preventing the handle 100 from collapsing when the user grips it, even when the handle 100 is manufactured with a thin wall thickness.

Furthermore, the manufacturing method of the handle 100 is not limited to stretch blow molding; for example, it can also be manufactured using injection blow molding. Even when using injection blow molding, the strength of the handle 100 can be improved in the same way as when using stretch blow molding.

When the stem 100 is manufactured using blow molding (stretch blow molding or injection blow molding), a cold preform method (two-stage method) can be used to improve production efficiency. Alternatively, a hot preform method (one-stage method) can also be used to manufacture the stem 100.

The resin material used in manufacturing the handle 100 is not particularly limited if it is a material suitable for blow molding; however, resin materials primarily composed of polyethylene, polypropylene, polyethylene terephthalate, polylactic acid, polyhydroxybutyrate, or polystyrene are preferred. Furthermore, the resin material used in manufacturing the handle 100 is more preferably a polyethylene terephthalate-based material. When using a polyethylene terephthalate-based resin material, the difference in specific gravity between it and the material constituting the head 210 (described later) becomes significant, allowing users to easily separate the handle 100 from the head 210. Additionally, existing recycling systems that separate the materials based on their specific gravity can also be utilized.

The handle body 110 can be printed or colored. From a recycling perspective, the handle body 110 is preferably manufactured in a colorless manner.

To improve the design flexibility of the handle body 110, solids such as resin or paper, semi-solids such as gels, or colored liquids can be filled into the internal space 113. Preferably, the solid or semi-solid material filling the internal space 113 is easily separable from the handle body 110. For example, spherical beads or strip-shaped films are preferred.

Furthermore, a more preferable method to improve the design of the handle body 110 is to provide a shrink label on the outer surface of the handle body 110. If the handle body 110 is decorated with a shrink label, it is easy to separate the handle body 110 from the shrink label, thus improving material recyclability. The contact angle of the shrink label surface relative to the outer surface of the handle body 110 is preferably, for example, 60° or more. By setting the contact angle to 60° or more, the slippage of the toothbrush can be suppressed, preventing water from seeping into the gap between the handle body 110 and the shrink label. Additionally, from the viewpoint of inhibiting bacterial growth, the shrink label is preferably treated with an antibacterial finish.

As shown in Figures 1 and 2, the handle neck portion 120 is integrally formed with the handle body 110 and extends to the front end of the handle body 110.

The opening 130, like the handle body 110, has a hollow structure. Inside the opening 130, a hollow portion 133 is formed, communicating with the internal space 113 of the handle body 110.

A mouth portion 130 is disposed at the front end of the handle portion 100. A front opening portion 131 is formed at the front end of the mouth portion 130.

The outer diameter D2 of the opening 130 (see Figure 2) is smaller than the outer diameter D1 of the handle body 110 (see Figure 1). Furthermore, when the opening 130 has a first recess 135, the outer diameter D2 of the opening 130 is the outer diameter of the portion other than where the first recess 135 is formed.

The outer diameter D2 of the opening 130 can be formed, for example, between 7.0 mm and 14.0 mm. Furthermore, considering the outer diameter D1 of the stem body 110 and the elongation during molding using the stretch blow molding method, the outer diameter D2 of the opening 130 is preferably between 8.0 mm and 13.0 mm, and more preferably between 9.0 mm and 12.0 mm.

In the toothbrush 10 according to this embodiment, the ratio (D1/D2) of the outer diameter of the handle body 110 to the outer diameter of the mouth portion 130 can be set to 1.2 or more and 10 or less. This is based on the following reasons.

In toothbrush 10, a large outer diameter ratio (D1/D2) indicates that more resin remains on the mouth 130 side during blow molding and that the resin is stretched longer on the handle body 110 side. Therefore, it can be understood that for toothbrush 10, a larger outer diameter ratio (D1/D2) means the handle body 110 is formed with a thinner wall, resulting in a reduction in the amount of resin in the handle body 110. On the other hand, if the outer diameter ratio (D1/D2) becomes too large, a significant reduction in the strength of the handle body 110 occurs due to the thinning of the handle body 110. In the case of blow molding, the strength of the handle body 110 can be improved by adjusting the resin alignment during stretching. Taking this aspect into account, the outer diameter ratio (D1/D2) is preferably 1.2 or higher and 10 or lower, more preferably 1.6 or higher and 6 or lower.

Regarding the toothbrush 10, when the outer diameter ratio (D1/D2) is 1.2 or higher and 10 or lower, the outer diameter D1 of the handle body 110 is preferably 20 mm, for example, and the outer diameter D2 of the mouth part 130 is preferably 8 mm, for example.

The length L2 of the mouth portion 130 along its long side (refer to Figure 1) can be, for example, 5 mm or more and 20 mm or less. Furthermore, from the viewpoint of preventing damage to the periphery of the mouth portion 130 due to the torque applied to it during brushing, the length L2 of the mouth portion 130 along its long side is preferably 5 mm or more and 16 mm or less, and more preferably 5 mm or more and 12 mm or less.

The starting and ending points of the measurement datum for the length L2 of the mouth 130 along its long side are the front end and base end of the mouth 130. The base end of the mouth 130 is located at the boundary between the mouth 130 and the shoulder 140. This boundary is the position where the curvature changes relative to the outer diameter (width) of the curve or straight line from the shoulder 140 side to the mouth 130 side when viewed from the front in FIG1, or the position where the angle changes (parallel to the central axis c1). Furthermore, the measurement datum for L2 can also be applied in the various variations described later (e.g., the variation shown in FIG9). Furthermore, in the case where the mouth 130 has an asymmetrical shape in the circumferential direction near its base (as shown in the cross-sectional view in Figure 2, etc.), the boundary on the base side, which serves as the reference for the length L2 of the mouth 130 along its long side, can be defined as the position where the measured length L2 becomes the shortest.

In the toothbrush 10 according to this embodiment, the length ratio (L1/L2) of the handle body 110 along its long side to the mouth portion 130 along its long side can be set to 2.5 or more and 30 or less. This is based on the following reasons.

As shown in Figures 1 and 2, when brushing teeth with the mouth part 130 connected to the brush neck part 220, the handle part 100 is supported by the brush neck part 220 via the mouth part 130. Considering the load applied to the mouth part 130, it is preferable that the mouth part 130 has a length greater than a specified value. In particular, if the handle body 110 is made longer, the torque acting on the mouth part 130 during brushing also increases, so as a countermeasure, it is necessary to make the mouth part 130 longer. On the other hand, if the mouth part 130 is made too long, the handle part 100 will also be made longer, and the overall length of the toothbrush 10 will also increase. As a result, the operability of the toothbrush 10 during brushing is reduced. In addition, by increasing the overall length of the toothbrush 10, the amount of resin used in the toothbrush 10 also increases. Based on the reasons above, the length ratio (L1/L2) is preferably 2.5 or higher and 30 or lower, and more preferably 7.5 or higher and 25 or lower.

Regarding the toothbrush 10, when the length ratio (L1/L2) is 2.5 or more and 30 or less, the length L1 of the handle body 110 along its long side is preferably, for example, 120 mm, and the length L2 of the mouth 130 along its long side is preferably, for example, 8 mm.

The wall thickness t2 of the mouth portion 130 (refer to FIG. 2) can be formed to be, for example, 0.8 mm or more and 3 mm or less. Furthermore, from the viewpoint of preventing deformation of the mouth portion 130 during brushing when connected to the brush-side neck portion 220, the wall thickness t2 of the mouth portion 130 is preferably 0.9 mm or more and 2.5 mm or less, more preferably 1.0 mm or more and 2.0 mm or less. Moreover, when the mouth portion 130 has the first recess 135, the wall thickness t2 of the mouth portion 130 is the wall thickness of the portion other than where the first recess 135 is formed.

As shown in Figure 2, a first recess 135 can be formed on the outer peripheral surface of the opening 130, recessed radially inward (in the same direction as the central axis c1).

The first recess 135 has a semi-circular cross-sectional shape. The first recess 135 is formed near the approximate center position along the long side of the opening 130. The first recess 135 is formed along the entire circumference of the outer peripheral surface of the opening 130.

The height of the first recess 135 (equivalent to the wall thickness of the opening 130 at the first recess 135) is preferably, for example, 0.3 mm or more and 2.0 mm or less. When the first recess 135 is formed within this height range, as shown in FIG. 2, with the second protrusion 235 formed in the inner cylinder portion 240 disposed in the first recess 135, the engagement of the first recess 135 and the second protrusion 235 effectively prevents accidental separation of the handle-side neck portion 120 and the brush-side neck portion 220.

Furthermore, the location, cross-sectional shape, and number of the first recess 135 are not particularly limited and can be adapted. Alternatively, a first protrusion, for example, projecting radially outward from the opening 130, can be provided on the opening 130. The shape, location, and number of the first protrusion are also not particularly limited. Furthermore, only the first recess 135, only the first protrusion, or both can be formed on the opening 130.

As shown in Figure 1, the neck portion 120 of the handle has a shoulder 140, which is formed on the base end side in the long side direction compared to the mouth portion 130.

The outer diameter of the shoulder 140 gradually increases from the mouth 130 towards the handle body 110. The shoulder 140 has a hollow structure that connects the hollow portion 133 of the mouth 130 located at the front end of the shoulder 140 with the internal space 113 of the handle body 110.

Furthermore, the shoulder 140, when viewed from the front as shown in FIG. 1, has a curved shape in which the outer diameter gradually increases from the mouth 130 side towards the handle body 110 side, or it can be formed, for example, a straight line shape in which the outer diameter gradually increases from the mouth 130 side towards the handle body 110 side. Alternatively, the handle 100 may also be a structure without the shoulder 140. In this configuration, the handle 100 can be connected to the brush neck 220 via the mouth 130.

The total length of the handle 100 along its long side (the length obtained by adding the handle body 110 and the handle neck 120) can, for example, be between 55 mm and 180 mm.

<Brushing Department>

As shown in Figures 1 and 2, the brush portion 200 includes: a head portion 210 with bristle bundles 211 embedded therein; and a brush-neck portion 220 extending from the head portion 210 towards its base in the longitudinal direction and having a connecting portion 230 capable of connecting/separating from the opening portion 130.

A connecting portion 230 is formed at the base end of the brush portion 200 (the base end of the brush neck portion 220).

As shown in Figure 2, the connecting portion 230 has an insertion portion 231 into which the opening portion 130 and the shoulder portion 140 are inserted. In this embodiment, the insertion portion 231 is formed by the space divided by the inner periphery of the inner cylindrical portion 240 and the outer cylindrical portion 250 included in the connecting portion 230.

The brush neck portion 220 has a locking structure that does not create a space connecting the interior and exterior of the head portion 210. Specifically, as shown in FIG. 2, the connecting portion 230 of the brush neck portion 220 has a front end face 232 that blocks the connection between the interior of the brush neck portion 220 and the hollow insertion portion 231 facing the exterior of the brush neck portion 220. Therefore, no space, passage, or hole is formed inside the brush neck portion 220 that connects the interior and exterior of the head portion 210.

As shown in Figures 2 and 3, the connecting portion 230 has an inner cylinder portion 240 and an outer cylinder portion 250 disposed such that it is spaced apart from and covers the inner cylinder portion 240 by a gap g.

The connecting portion 230, formed at the base end of the brush neck portion 220, is given a shape resembling two cylinders. Of the two cylinders, the portion located on the inner periphery of the connecting portion 230 constitutes the inner cylinder portion 240, and the portion disposed on the outer periphery of the inner cylinder portion 240 constitutes the outer cylinder portion 250.

Furthermore, the connecting portion 230 may not be formed as a double-cylinder structure including the inner cylinder portion 240 and the outer cylinder portion 250. For example, a space capable of inserting the opening portion 130 and the shoulder portion 140 can also be formed by a recess divided by the inner periphery.

As shown in Figure 2, a second protrusion 235 is formed in the connecting portion 230. When the opening portion 130 and the shoulder portion 140 are inserted into the insertion portion 231, the second protrusion 235 abuts against the outer peripheral surface of the first recess 135.

A second protrusion 235 is disposed on the inner peripheral surface of the inner cylindrical portion 240 constituting the connecting portion 230. The second protrusion 235 protrudes radially inward toward the connecting portion 230 (in the same direction as the central axis c1). The second protrusion 235 has a semi-circular cross-sectional shape that matches the shape of the first recess 135.

The second protrusion 235 is formed at a position corresponding to the location where the first recess 135 is formed. Furthermore, the second protrusion 235 is formed along the entire circumference of the inner circumference of the inner cylinder portion 240. Therefore, when the opening portion 130 and the shoulder portion 140 are inserted into the insertion portion 231, the second protrusion 235 abuts against the outer circumference of the first recess 135 throughout its entire circumference.

The height of the second protrusion 235 (equivalent to the wall thickness of the inner cylinder portion 240 at the second protrusion 235) is preferably 0.3 mm or more and 2.0 mm or less, for example, similar to the first recess 135.

Furthermore, the position, cross-sectional shape, and number of the second protrusions 235 can be adapted to correspond with the first recess 135. For example, if only the first recess 135 is formed in the opening 130, only the second protrusions 235 can be formed in the connecting portion 230. Alternatively, if both the first recess 135 and the first protrusion are formed in the opening 130, the connecting portion 230 can also have a second protrusion 235 and a second recess that abuts against the first protrusion.

From the viewpoint of inducing appropriate deformation of the inner cylinder portion 240 when the opening 130 and shoulder 140 are inserted into the insertion portion 231, the wall thickness ta of the inner cylinder portion 240 (refer to FIG. 2) can be formed, for example, between 0.3 mm and 1.5 mm. The wall thickness ta of the inner cylinder portion 240 is preferably between 0.4 mm and 1.3 mm, and more preferably between 0.6 mm and 1.1 mm. Furthermore, the illustrated wall thickness ta is the dimension of the thinnest portion of the inner cylinder portion 240, which in this embodiment is the wall thickness near the base end of the inner cylinder portion 240.

From the viewpoint of protecting both the opening 130 and the inner cylinder 240 from the outside and ensuring the sealing of the connection 230 when the opening 130 is inserted into the insertion part 231, the wall thickness tb of the outer cylinder 250 (refer to FIG. 2) can be formed, for example, 1 mm or more and 2 mm or less. The wall thickness tb of the outer cylinder 250 is preferably 0.6 mm or more and 2.5 mm or less, more preferably 0.8 mm or more and 1.8 mm or less. Furthermore, the illustrated wall thickness tb is the dimension of the thinnest part of the outer cylinder 250, which in this embodiment is the wall thickness near the base end of the outer cylinder 250.

In the toothbrush 10 of this embodiment, the wall thickness ratio (ta/tb) of the inner tube 240 wall thickness ta to the outer tube 250 wall thickness tb is preferably 0.15 or more and 1.5 or less. This is based on the following reasons.

When the toothbrush 10 is inserted into the insertion portion 231, the inner tube portion 240 deforms in an expanded manner, thereby improving the insertion ease of the mouth 130 and shoulder 140. Therefore, it is undesirable to form an excessively large wall thickness ta of the inner tube portion 240. Furthermore, from the viewpoint of externally protecting the mouth 130 and inner tube portion 240 and ensuring the sealing of the connection portion 230, it is undesirable for the outer tube portion 250 to be constructed in a manner that allows for easy deformation, similar to the inner tube portion 240. For the reasons stated above, it is undesirable for the wall thickness tb of the outer tube portion 250 to be too small than the wall thickness ta of the inner tube portion 240; the wall thickness ratio (ta/tb) is preferably 0.15 or more and 1.5 or less, more preferably 0.3 or more and 1.0 or less.

From the viewpoint that the outer cylinder 250 deforms during the pressing operation described later, thereby facilitating the separation of the connecting portion 230 from the opening 130 and the shoulder 140, the distance tc of the gap g formed between the inner cylinder 240 and the outer cylinder 250 (see Figure 3) is preferably formed to be, for example, 1 mm or more and 3 mm or less.

The material constituting the brush part 200 is not particularly limited; for example, polypropylene, polyethylene, polyethylene terephthalate or polybutylene terephthalate, polyacetal, polystyrene, nylon, acrylonitrile styrene resin, etc., can be used. The resin constituting the brush part 200 is preferably polypropylene or polyethylene. Furthermore, when the head 210 is manufactured by integral molding, the bristles constituting the bristle tuft 211 are preferably not hairs, but rather a high-hardness elastic material, especially any of polyamide, polyester, polystyrene, polyurethane, or silicone resin. Additionally, when the bristle tuft 211 and the head 210 are manufactured by integral molding, the bristles constituting the bristle tuft 211 are more preferably thermoplastic polyurethane with a hardness of A of 40 or higher.

The head 210 may have a structure in which hair tufts 211 are implanted by linear hair grafting or anchor-free hair grafting, or it may have a structure in which the hair tufts 211 are integrally formed with the head 210, as described above. If the hairs constituting the hair tufts 211 are not integrally formed with the head 210, they may be made of known materials such as nylon, polybutylene terephthalate, or polyethylene terephthalate.

Furthermore, there are no particular limitations regarding the shape or size of the head 210, the material of the hairs constituting the hair tufts 211, the number of hairs implanted, the implantation area, the outer diameter, etc., and known structures can be appropriately adopted.

The resin material constituting the brush neck 220 is preferably a hard material. By selecting this resin material, in the case of a toothbrush 10 of this embodiment where the handle 100 and brush part 200 are connected with the connecting part 230 covering the mouth part 130, the outer peripheral surface of the mouth part 130 can be covered by a hard resin. This prevents accidental deformation of the connecting part 230 when the handle 100 and brush part 200 are connected, and effectively prevents a decrease in the airtightness of the internal space 113 of the handle body 110. For example, the resin material combination used to achieve the aforementioned effects can include, for instance, polyethylene, polypropylene, or polyethylene terephthalate (PET) for the handle 100, and polyacetal, polybutylene terephthalate (PPT), polytetrafluoroethylene (PTFE), PCTA (a resin containing dicarboxylic acid components mainly composed of terephthalic acid and isophthalic acid, and a diol component mainly composed of 1,4-cyclohexanediethanol glycol), polyethylene terephthalate (PET), acrylonitrile styrene, polypropylene, or polyethylene for the brush neck 220. The combination of resin materials to achieve the aforementioned effects can include, for example, polyethylene, polypropylene, or polyethylene for the handle 100, polyethylene, polypropylene, polypropylene, polypropylene, and polyethylene.

<Sealing Mechanism>

As shown in Figure 2, the toothbrush 10 has a sealing mechanism 300 that maintains the airtightness of the internal space 113 of the handle body 110 when the mouth portion 130 and the connecting portion 230 are connected.

The sealing mechanism 300 includes a fitting portion 310, which maintains the airtightness of the internal space 113 of the handle body 110 by fitting the handle-side neck portion 120 with the brush-side neck portion 220 through insertion of the opening portion 130 and the shoulder portion 140 into the insertion portion 231.

When using the toothbrush 10, the user can easily connect the handle 100 and the brush part 200 by inserting the insertion part 231 into the mouth 130 and shoulder 140. Furthermore, by connecting the handle 100 and the brush part 200, the user can maintain the airtightness of the internal space 113 of the handle body 110 using the sealing mechanism 300 formed in the connection area between the handle 100 and the brush part 200.

As the mouth portion 130 and shoulder portion 140 of the handle-side neck portion 120 are inserted into the insertion portion 231 of the connecting portion 230 of the brush-side neck portion 220, the fitting portion 310 partially seals the mouth portion 130 and the connecting portion 230 together. The toothbrush 10 seals the periphery of the mouth portion 130 and shoulder portion 140 through the fitting portion 310. In the toothbrush 10, the first recess 135 and the second protrusion 235, the front end face 132 of the mouth portion 130 and the front end face 232 of the connecting portion 230, and the shoulder portion 140 and the base end faces 242 and 252 of each of the tube portions 240 and 250 cooperate to form the fitting portion 310.

The sealing mechanism 300 (fitting part 310) is not limited in its specific structure as long as it can maintain the airtightness of the internal space 113 of the handle body 110 when the handle side neck 120 and the brush side neck 220 are mechanically connected. For example, the sealing mechanism 300 can also be configured to maintain the airtightness of the internal space 113 of the handle body 110 by having the outer peripheral surface of the opening 130 in close contact with the inner peripheral surface of the inner cylinder 240 throughout the entire area along the long side. Alternatively, for example, the sealing mechanism 300 can be configured to maintain the airtightness of the internal space 113 of the handle body 110 by engaging the threads formed on the outer peripheral surface of the opening 130 with the threads formed on the inner peripheral surface of the inner cylindrical portion 240 constituting the connecting portion 230.

As shown in Figure 2, when the mouth 130 and shoulder 140 are inserted into the insertion portion 231, the front end face 132 of the mouth 130 abuts against the front end face 232 of the connecting portion 230 located on the front end side of the insertion portion 231. Therefore, when the handle-side neck 120 and brush-side neck 220 are connected, the front end face 132 of the mouth 130 and the front end face 232 of the connecting portion 230 are in close contact, thus improving the sealing performance of the sealing mechanism 300.

Furthermore, as shown in Figure 2, the base end face 242 of the inner cylinder 240 and the base end face 252 of the outer cylinder 250 abut against the shoulder 140 when the opening 130 and shoulder 140 are inserted into the insertion portion 231. Therefore, when the handle neck portion 120 and the brush neck portion 220 are connected, the base end face 242 of the inner cylinder 240 and the base end face 252 of the outer cylinder 250 are in close contact with the shoulder 140, thus further improving the sealing performance of the sealing mechanism 300.

Furthermore, when the brush neck portion 220 includes an inner cylinder portion 240 and an outer cylinder portion 250, the sealing performance of the sealing mechanism 300 can be improved by configuring the base end face 242 of the inner cylinder portion 240 and the base end face 252 of the outer cylinder portion 250 to abut against the shoulder portion 140. Therefore, as shown in this embodiment, it is not necessary for each base end face 242, 252 of the inner cylinder portion 240 and the outer cylinder portion 250 to abut against the shoulder portion 140; for example, it is possible for only one base end face to abut against the shoulder portion 140.

Next, referring to Figures 4 and 5, the sequence of operations for separating the brush neck 220 from the handle neck 120 will be explained.

The engaging portion 310 is configured to release the engagement between the connecting portion 230 and the mouth portion 130 and shoulder portion 140 by pressing the connecting portion 230 of the brush neck portion 220 from the outer peripheral side. Specifically, as shown in FIG4, the user pinches the outer peripheral surface of the outer tube portion 250 constituting the connecting portion 230 with their fingers and applies a force F, thereby bending the outer tube portion 250 toward the gap g. When the outer tube portion 250 is bent toward the gap g, the inner peripheral surface of the outer tube portion 250 contacts the inner tube portion 240. The inner tube portion 240 is released from the engagement of the second protrusion 235 with the first recess 135 by being pushed from the outer peripheral side of the inner tube portion 240.

As shown in Figure 5, the user can easily disconnect the handle 100 and brush 200 by moving the handle 100 and brush 200 apart in a relatively disengaged manner towards the front end and base end when the second protrusion 235 is released from the first recess 135.

As described above, the toothbrush 10 of this embodiment, by constructing the handle 100 and head 210 in a manner that allows for connection/separation, improves material recyclability and provides a variety of toothbrush types. Furthermore, when the handle 100 and head 210 are connected, the airtightness of the internal space 113 of the handle body 110 can be maintained, thereby increasing the strength of the handle body 110. Therefore, accidental deformation of the handle body 110 can be prevented during brushing. This suppresses the reduction in usability associated with deformation of the handle body 110 during brushing. Furthermore, by increasing the strength of the handle body 110, the toothbrush 10 can achieve further thinning of the handle body 110's walls. This further improves material recyclability.

Next, variations of the toothbrush according to this invention will be described. In the description of each variation, repetitive descriptions related to components or content already described in the embodiments will be omitted.

<Variation Example 1>

Figure 6 shows a partial cross-sectional view of the toothbrush involved in variant example 1.

In variant example 1, the fitting portion 310 is configured to disengage the mouth portion 130 and shoulder portion 140 from the insertion portion 231 during a rotational operation that causes the brush portion 200 and handle portion 100 to rotate relative to each other.

As shown in Figure 6, the inner cylinder portion 240 and the outer cylinder portion 250 constituting the connecting portion 230 are configured such that, in a portion circumferentially aligned with the central axis c1, their lengths along the long side are different. In the example shown in Figure 6, the lower portion of the inner cylinder portion 240 and the upper portion of the outer cylinder portion 250 are formed to be longer than the upper portion. Furthermore, corresponding to the difference in length between the shoulder portion 140 and the inner cylinder portion 240 and the outer cylinder portion 250, the shoulder portion is formed into a circumferentially vertical, wall-like cross-sectional shape.

If the user rotates the inner cylinder 240 and outer cylinder 250 as indicated by arrow r in the diagram, the longer portions of the inner and outer cylinders 240 and 250 will come into contact with the upright portion of the shoulder 140. This allows the user to disengage the engagement via the fitting part 310, easily separating the handle 100 from the brush part 200.

<Variation Example 2>

Figures 7 and 8 show partial cross-sectional views of the toothbrush involved in variant example 2.

In the toothbrushes of Variations 2 and 3, the mouth portion 130 has a defined thick-walled portion 138. The thick-walled portion 138 is located further towards the base end than the front end of the mouth portion 130, and is formed such that its wall thickness is greater than that of the front end of the mouth portion 130. The toothbrush having the thick-walled portion 138 has the following advantages.

When the handle 100 is manufactured by blow molding, pre-forming the thick-walled portion 138 allows the handle body 110 to extend and expand uniformly along its long side during blow molding. This prevents the formation of areas with localized strength reduction in the handle body 110.

Regarding the thick-walled portion 138, it can be configured, for example, as shown in FIG. 7, as a neck-ring shape (a ring shape formed by increasing the outer diameter of a portion of the opening 130), or as shown in FIG. 8, as a neck-shoulder shape (a shape in which the wall thickness increases from the base end of the opening 130 towards the shoulder 140). When the thick-walled portion 138 is configured as a neck-ring shape, it can be engaged and transported during the toothbrush manufacturing process, thus improving productivity.

The wall thickness ratio (t3/t1) of the thick-walled portion 138 to the wall thickness t1 of the opening portion 130 (see Figure 1) is preferably 1.2 to 3, and more preferably 1.5 to 2.5.

<Variation Example 3>

Figures 9-11 show a variation 3 related to the shape of the handle body 110.

The cross-sectional shape of the handle body 110 does not necessarily have to be a cylindrical shape that is approximately fixed along the long side as shown in Figure 1. For example, from the viewpoint of improving strength, it can also be formed into a barrel shape, as shown in Figure 9, where the cross-sectional area at the base end is larger than that at the front end. Furthermore, it can be formed, for example, into a shape where the cross-sectional shape orthogonal to the central axis c1 is formed by a polygon, or into a shape with a neck that periodically increases or decreases in cross-sectional area. Regarding the method of holding the toothbrush, methods such as holding a stick or holding a pen are known. When holding the toothbrush using these methods, in order to allow the user to hold the toothbrush firmly, recesses or other irregularities can be provided to accommodate the thumb, index finger, and middle finger.

Furthermore, the strength of the handle body 110 can also be improved by providing ribs extending circumferentially as shown in FIG. 10 (transverse ribs 111a) and/or ribs extending along the long side direction as shown in FIG. 11 (longitudinal ribs 111b).

<Variation Example 4>

Figures 12-14 show a variation 4 related to the work done to improve the sealing performance of the sealing mechanism 300 (fitting part 310).

For example, as shown in Figure 12, the toothbrush may also have a sealing member 410 disposed between the front end face 132 of the mouth portion 130 and the front end face 232 of the connecting portion 230. By configuring the sealing member 410, the toothbrush can improve the tightness between the front end face 132 of the mouth portion 130 and the front end face 232 of the connecting portion 230. This further improves the airtightness of the internal space 113 of the handle body 110. The sealing member 410 may, for example, be composed of a known O-ring such as an elastomer, or a ring or sheet of low-hardness polyethylene (PE) or polypropylene (PP).

For example, as shown in Figure 13, the toothbrush may also have a flap structure 420 on the front end face 232 of the connecting portion 230 to improve the airtightness between the front end face 132 of the mouth portion 130 and the front end face 232 of the connecting portion 230. The flap structure 420 may, for example, be a pointed flap portion protruding from the front end face 232 of the connecting portion 230 towards the central axis c1. By providing the flap structure 420, the toothbrush can improve the tightness between the front end face 132 of the mouth portion 130 and the front end face 232 of the connecting portion 230. This further improves the airtightness of the internal space 113 of the handle body 110.

For example, as shown in Figure 14, the toothbrush may also have a bonding material 430 disposed between the outer peripheral surface of the mouth portion 130 and the inner peripheral surface of the inner barrel portion 240. The bonding material 430 is preferably, for example, a non-water-soluble and water-repellent grease with appropriately adjusted viscosity. By providing the bonding material 430, the toothbrush can improve the adhesion between the outer peripheral surface of the mouth portion 130 and the inner peripheral surface of the inner barrel portion 240. This further improves the airtightness of the internal space 113 of the handle body 110.

Furthermore, the structures described in each of the modifications can be selectively and arbitrarily combined into the toothbrush of the present invention, provided that the effectiveness of each modification is not compromised.

The toothbrush described above, through embodiments and variations, illustrates the present invention. However, the present invention is not limited to the content described in the specification and may be adapted to the scope of the patent application.

For example, the toothbrush described in the embodiments illustrates a structure in which a portion of the handle-side neck is covered by the brush-side neck when the handle and brush parts are connected, but this is not a limitation. The toothbrush may also have a structure in which a portion of the brush-side neck is covered by the handle-side neck when the handle and brush parts are connected. That is, it may also have a structure in which a portion of the brush-side neck is inserted into the handle-side neck.

10: Toothbrush

100: Handle

110: Handle Body

113: Interior Space

120: Handle side and neck area

130: Mouth area

133: Hollow Section

140: Shoulders

200: Brush Department

210: Head

211:hair bundle

220: Brush the sides of the neck

230: Connecting Part

240: Inner cylinder section

250:Outer cylinder part

300: Sealing mechanism

310: Chimeric part

D1: Outer diameter of the main body of the stem

c1: The central axis of the toothbrush

t1: Wall thickness of the main body of the handle

L1: Length of the main body of the handle along its long side

L2: Length of the mouth along its long side

X1, X2: Arrows

Claims (8)

A toothbrush includes a handle, a brush head, and a sealing mechanism. The handle includes a handle body having a hollow internal space and configured for gripping; and a handle neck portion disposed at a front end further along the long side of the handle body and having a hollow opening communicating with the internal space. The brush head includes a head with bristles; and a brush neck portion extending from the head towards its base along the long side and having a connecting portion capable of connecting and separating from the opening. The sealing mechanism maintains the airtightness of the internal space when the opening and the connecting portion are connected, and the brush neck portion... The brush has a locking structure that does not create a space connecting the inside and outside of the head. The outer diameter of the mouth is smaller than the outer diameter of the handle body. The handle neck has a shoulder that is formed on the base end side in the long direction compared to the mouth, and its outer diameter gradually increases from the mouth side towards the handle body side. The connecting portion has an insertion portion for inserting the mouth and the shoulder. The sealing mechanism includes a fitting portion that maintains the airtightness of the internal space by fitting the brush neck with the handle neck as the mouth and the shoulder are inserted into the fitting portion. The toothbrush of claim 1, wherein the front end face of the mouth abuts against the front end face of the connecting portion located on the front end side of the insert portion when the mouth and the shoulder are inserted into the insert portion. The toothbrush as described in claim 1 or claim 2, wherein a first recess recessing radially inward and/or a first protrusion radially outward are formed on the outer peripheral surface of the mouth portion, and a second protrusion abutting the outer peripheral surface of the first recess and/or a second recess abutting the outer peripheral surface of the first protrusion are formed on the connecting portion when the mouth portion and the shoulder portion are inserted into the insertion portion. The toothbrush as described in claim 1 or claim 2, wherein the ratio (D1/D2) of the outer diameter of the handle body to the outer diameter of the mouthpiece is 1.2 or more and 10 or less. The toothbrush as described in claim 1 or claim 2, wherein the length ratio (L1/L2) of the handle body along its long side (L1) to the mouthpiece along its long side (L2) is 2.5 or more and 30 or less. The toothbrush as described in claim 1 or claim 2, wherein the engaging portion is configured to disengage upon a pressing operation of pressing the connecting portion from the outer peripheral surface, or a rotational operation of rotating the brush portion relative to the handle portion. The toothbrush as described in claim 1 or claim 2, wherein the connecting portion has an inner tube portion and an outer tube portion disposed such that it is spaced apart from and covers the inner tube portion, the base end face of the inner tube portion and/or the base end face of the outer tube portion abutting against the shoulder portion when the mouth portion and the shoulder portion are inserted into the insertion portion. The toothbrush as described in claim 1 or claim 2, wherein the mouth has a thick-walled portion that is located further to the base end than the front end of the mouth and is formed such that the wall thickness is greater than that of the front end of the mouth.