JP7819985B2 - toothbrush - Google Patents

Description

The present invention relates to a toothbrush, and more specifically to a toothbrush that has a head with bristles attached to the tip, and a handle that is gripped to guide the head into the oral cavity.

Conventionally, there are toothbrushes with a hollow structure in which part of the shaft is formed into a hollow cylinder (Patent Document 1). These conventional toothbrushes with a hollow structure are relatively lightweight because the hollow part is not filled with a material such as synthetic resin that forms the rest of the body.

In addition, the degree of flex of the shaft can be adjusted by changing the dimensions of the hollow portion. In other words, when the hollow portion is elongated in the longitudinal direction of the shaft, the hardness when cleaning teeth can be adjusted by changing the length and position of the hollow portion in the longitudinal direction, and the force applied by the brush to parts of the oral cavity can be cushioned.

As a result, conventional hollow-structure toothbrushes can be used lightly, and the hardness of the brush can be adjusted when cleaning teeth, making it possible to meet a variety of needs, such as the user's physical strength and cleaning strength.

International Publication No. 2015/137180

In conventional toothbrushes with a hollow structure, the hollow portion is formed in a roughly cylindrical shape and extends straight along the length of the toothbrush. As a result, when a shearing force is applied to the toothbrush that bends the head and handle sides when applying force to the bristles, the straight portion has difficulty withstanding the shearing force, and there is a high risk of it bending at the point where the force is concentrated. Alternatively, if the strength is increased to prevent such bending, the bristles will not be able to adequately cushion the force applied to parts of the oral cavity.

Furthermore, when a toothbrush bends in this way, the bent part can injure the user's mouth. Furthermore, once bent, the toothbrush does not easily return to its original shape, making it impossible to continue using the toothbrush.

The objective of this invention is to provide a toothbrush that has a hollow structure, can cushion the force applied by the bristles to areas inside the mouth when cleaning the teeth to an extent that it does not injure the inside of the user's mouth, and can be manufactured with the degree of cushioning easily adjusted.

(1) The present invention provides a toothbrush comprising: a head member that forms a head section with bristles attached to the tip; and a hollow member that is connected to the head member and forms a handle section that is gripped to guide the head section into the oral cavity, the hollow member being hollow and made of an elastic material, the hollow member having a flange-like portion that protrudes in a direction away from its central axis, the flange-like portion being hollow and its interior communicating with the interior of the hollow cylindrical portion. Furthermore, the flange-like portion is formed in a substantially circular shape when viewed in the direction of the central axis, and has a substantially annular front portion and a substantially annular back portion that are arranged opposite each other and sandwiching the interior in the direction of the central axis, and at least one of the front portion and the back portion may have an inclined surface whose diameter decreases with increasing distance from the other of the front portion and the back portion, or a convex partial spherical surface whose diameter also decreases.

In other words, the toothbrush of the present invention is lightweight because it has a hollow member that forms the handle and does not contain a material such as synthetic resin inside the hollow member. Therefore, even users with weak grip strength, such as elderly people or young children, can easily operate the toothbrush of the present invention and clean their teeth.

In addition, because the hollow member is made of an elastic material, the handle that the user grips is elastic and can cushion the force applied to areas inside the oral cavity via the head when cleaning teeth. Furthermore, because the hollow member is elastically deformable, the handle absorbs force and returns to its original shape after being deformed. This allows the user to continue cleaning their teeth.

Furthermore, the interior of the cylindrical portion and the interior of the flange are connected, and this simple internal structure does not hinder the flange's free deformation. For example, when a shearing force is applied to the toothbrush that bends the hollow member on the head side relative to the central axis of the toothbrush, the inner portion of the flange that attempts to bend on the head side is compressed, and the outer portion that attempts to bend can stretch. As a result, when the shearing force is applied, the side of the hollow member closer to the head than the flange can tilt in either direction relative to the side opposite the head than the flange. The head member can then swing freely relative to the hollow member.

The head member can tilt in any direction, allowing the user to evenly apply the bristles to each part of the oral cavity for cleaning. For example, if the head member could only tilt in a fixed direction, only part of the bristles might reach the area. In contrast, the toothbrush of the present invention allows the entire bristles to be applied in any direction or angle, resulting in a high cleaning effect. Furthermore, even if a small child or elderly person falls while holding the head member in their mouth, the toothbrush of the present invention can absorb impacts from all directions due to the head member's ability to tilt in any direction, reducing the risk of the head member poking the user's throat and causing injury.

In this way, by adjusting the thickness, shape, material, and other configurations of the flange during manufacturing, the degree to which the head member can freely tilt relative to the hollow member, i.e., the hardness of the entire toothbrush, can be easily adjusted. In this way, the toothbrush of the present invention can cushion the force applied by the bristles to areas inside the mouth when cleaning teeth to an extent that does not injure the inside of the user's mouth, and the degree of cushioning can be easily adjusted when manufactured.

Furthermore, because the hollow member has an internal structure in which the inside of the cylindrical portion and the inside of the flange portion are connected, when the material is synthetic resin, the entire member can be molded as a single unit, and it can be manufactured simply and efficiently by using a manufacturing method such as blow molding.

(2) The head member may also have an opening on the base end side, the tip of the hollow member may be inserted into the opening, and the opening edge of the opening and the flange portion of the hollow member may be adjacent to each other in the direction of the central axis.

In other words, when a user presses the brush against an area in the mouth to clean their teeth, the head member receives a recoil force from that area and transmits it to the hollow member connected to the head member. When this recoil force generates a shear force that bends the hollow member, this shear force is transmitted from the opening in the head member to the hollow member. In this case, with the toothbrush of the present invention, the opening edge of the opening and the flange of the hollow member are adjacent to each other, so the shear force is transmitted efficiently to the flange.

The hollow member cushions the shear force by elastically deforming, with the inner portion of the flange being crushed as it bends and the outer portion being stretched as it bends. Because the shear force is efficiently transmitted to the flange, the degree to which the hollow member cushions the shear force can be easily adjusted by adjusting the thickness, shape, material, and other configurations of the flange. Thus, the toothbrush of the present invention can cushion the force applied to areas inside the mouth by the bristles to an extent that does not injure the user's mouth when cleaning teeth, and can be manufactured with the degree of cushioning easily adjusted.

(3) The handle portion may also have a bulging portion that bulges away from the central axis in a portion other than the flange-shaped portion.

In other words, the toothbrush of the present invention has an elastically deformable handle and a bulging portion, so that the user can grasp the thick bulging portion with their fingers or their fingers and palm, making it easy for even the elderly and young children with weak grip strength to support the toothbrush. Furthermore, because the handle is made of a hollow member, it is soft, allowing even users with weak grip strength to firmly grip the hollow bulging portion. Therefore, the toothbrush of the present invention is less likely to be dropped while cleaning teeth.

(4) The handle portion may also have a constricted portion between the flange portion and the bulge portion that constricts in a direction approaching the central axis.

In other words, because the toothbrush of the present invention has a constricted portion, the user can place their fingers against this constricted portion to stabilize and support the toothbrush when cleaning their teeth. In particular, because the constricted portion is located between the flange and the bulging portion, the user can, for example, place their index finger against the constricted portion and their middle and ring fingers against the bulging portion, allowing the index finger to control the position, angle, etc. of the head while the middle and ring fingers, etc., securely grip the handle. In this way, the toothbrush of the present invention allows for efficient tooth cleaning.

(5) Furthermore, the tip of the hollow member may be fitted into the opening, and either the fitting region of the tip of the hollow member or the fitted region of the opening may have an engaging convex portion that protrudes in a direction away from the central axis, and the other of the fitting region and the fitted region may have an engaging concave portion that is recessed in the direction away, the engaging convex portion and the engaging concave portion engaging with each other, and the head member and the hollow member may be configured to be detachably connected.

In other words, because the head member and hollow member are detachably connected, the toothbrush of the present invention allows either the head member or the hollow member to be replaced. Therefore, for example, it is possible to discard only one of the head member and the hollow member and continue to use the other, eliminating waste and minimizing the burden on the global environment.

In addition, the head member can be separated from the hollow member and then reattached to the hollow member. This allows the user to remove the head member to expose the insertion area and the inserted area for cleaning. This allows the toothbrush of the present invention to be kept clean at all times.

In addition, although the toothbrush of the present invention allows the head member to tilt freely relative to the hollow member, the engagement between the convex and concave engaging portions reduces the risk of the head member becoming detached from the hollow member, even while cleaning teeth. This prevents accidents such as choking on the head member, making it safe to use.

(6) Furthermore, one of the insertion region and the inserted region may have an engaged surface that faces in the circumferential direction of the central axis, and the other of the insertion region and the inserted region may have an engaging surface that faces in the opposite direction to the engaged surface in the circumferential direction, and the engaging surface may engage the engaged surface in the circumferential direction, thereby preventing the head member and the hollow member from rotating relative to each other.

In other words, the toothbrush of the present invention has an engaging surface and an engaged surface, which prevents the head member from rotating around the central axis relative to the hollow member. Therefore, even though the head member is detachably attached to the hollow member, the head member does not rotate even when the user is gripping the handle and cleaning their teeth. This allows the user to efficiently clean their teeth by keeping the bristles in the specified direction.

(7) Furthermore, a male threaded portion may be provided on the outside of the tip of the hollow member, and a female threaded portion into which the male threaded portion can be threaded may be provided on the inside of the opening, so that the head member and the hollow member can be detachably connected.

In other words, because the head member and hollow member are detachably connected, the toothbrush of the present invention allows for the replacement of either the head member or the hollow member. The head member can also be separated from the intermediate member and then reattached to the intermediate member. Furthermore, because the toothbrush of the present invention has a male threaded portion and a female threaded portion that thread together, there is little risk of the head member coming off the hollow member, even while cleaning your teeth, for example.

(8) The flange portion may also be formed in a substantially circular shape when viewed in the direction of the central axis.

In other words, because the flange is substantially circular when viewed in the direction of the central axis, no linear mountain or valley folds are formed in the flange. Therefore, the deformation direction of the structure is less likely to be limited to a specific direction, as would be the case if linear mountain or valley folds were formed. This allows the flange to easily deform in various directions, and the lack of corners allows for flexible deformation.

As a result, the head member of the toothbrush of the present invention can be tilted more freely and can more easily cushion forces applied to areas inside the oral cavity.

(9) Furthermore, the flange-shaped portion may have a substantially annular front surface portion and a substantially annular back surface portion that are arranged opposite each other in the direction of the central axis so as to sandwich the interior, and at least one of the front surface portion and the back surface portion may have an inclined surface whose diameter decreases as it becomes farther from the other of the front surface portion and the back surface portion, or a convex partial spherical surface whose diameter also decreases.

In the toothbrush of the present invention, at least one of the front and back surfaces of the collar has an inclined surface or a partially convex spherical surface. This causes the hollow member's side closer to the head to tilt, causing the one surface to collapse and the other surface to move closer together. The inventors discovered that the force applied to create the tilt becomes constant once it exceeds a certain tilt (amount of deformation). Therefore, even if a force greater than a certain level is accidentally applied to the toothbrush while cleaning the oral cavity, the toothbrush of the present invention can adequately cushion the force. Thus, depending on the structure of the toothbrush of the present invention, the degree to which the force is cushioned can be easily adjusted by adjusting the thickness, shape, material, and other components of the collar during manufacturing.

In this way, the present invention provides a toothbrush that is lightweight, can cushion the force that the bristles apply to areas inside the mouth when cleaning the teeth to the extent that it does not injure the user's mouth, and has a structure that allows the degree of cushioning to be adjusted over a wide range during design and manufacturing. In particular, when a user such as a guardian or caregiver operates the toothbrush to clean the teeth of an infant or a care recipient, it can be difficult for the user to sense the amount of force being applied to the mouth of the person. In contrast, the toothbrush of the present invention has a head member that freely swings due to the extension and contraction of the flange, so it can fully absorb the applied force, making it extremely effective in protecting the mouth of the person whose teeth are being cleaned.

Furthermore, when synthetic resin is used as the material for the hollow member, the hollow structure allows for a corresponding reduction in the amount of synthetic resin used, providing a toothbrush that places less strain on the global environment.

1A and 1B are a front view and a right side view, respectively, of a toothbrush according to a first embodiment of the present invention; 2 is a perspective view of the toothbrush of FIG. 1 disassembled into a head member and a hollow member. 2A to 2C are a front view, a partial cross-sectional view from the right side, and a bottom view, respectively, of the head member of the toothbrush shown in FIG. 1. 2A to 2C are a partial cross-sectional view of the right side of the head member of the toothbrush shown in FIG. 1, an enlarged view of the partial cross-section of the right side, and an enlarged view of an undercut portion, respectively. 2A to 2D are a plan view, a side view, a front view, and a cross-sectional view of the hollow member of the toothbrush shown in FIG. 1, respectively. 2 shows a longitudinal cross-sectional view of the hollow member of the toothbrush shown in FIG. 1. 2 shows a partial right side view of the hollow member of the toothbrush shown in FIG. 1; 2 shows a partial right side cross-sectional view of the head member and a partial right side view of the hollow member in a combined state of the head member and hollow member of the toothbrush shown in FIG. 1 ; 2A to 2C show, in plan view, the toothbrush shown in FIG. 1 as it gradually bends backward. 2A to 2C show the toothbrush shown in FIG. 1 gradually bending backward, as viewed from the right side slightly forward. 2A to 2C are right side cross-sectional views of the toothbrush shown in FIG. 1 as it gradually bends backward. (a) shows the state of the device used to measure the bending strength of the toothbrush shown in Figure 1 before the measurement started, and (b) shows the state of the same device after the measurement started. 2 is a right side view of the toothbrush shown in FIG. 1 during measurement of bending strength. 2 shows the results of measuring the bending strength of the toothbrush shown in FIG. 1. 1 shows a front view of a toothbrush according to a second embodiment of the present invention. 10 is a partial front view of a toothbrush according to a third embodiment of the present invention. 10A and 10B are a front view and a right side view, respectively, of a toothbrush according to a fourth embodiment of the present invention. 18 shows a partial cross-sectional plan view of the head member and a partial plan view of the hollow member in a combined state of the head member and hollow member of the toothbrush shown in FIG. 17. 1 shows a partial front view of a toothbrush according to a modified embodiment of the present invention.

[First embodiment]
A first embodiment of the present invention will be described with reference to Figures 1 to 14. In the front view of Figure 1(a) and the right side view of Figure 1(b), reference numeral 11 denotes a toothbrush. The toothbrush 11 has a head portion 12 at the tip end and a handle portion 13 that is gripped to guide the head portion 12 into the oral cavity. Bristles 14 are attached to the head portion 12. In the figures, arrow U points upward and arrow D points downward of the toothbrush 11. Arrow F points forward and arrow B points backward. Arrow L points left and arrow R points right.

The central axis of the toothbrush 11 is represented by the center line C1. The cross sections of the neck portion 12a of the head portion 12 and the cross sections near the upper and lower ends of the handle portion 13 are each formed into a roughly circular shape, with the central axis C1 passing through the center of each of these cross sections in the vertical direction. This neck portion 12a refers to the part of the head portion 12 located below the bristle implantation surface 12b where the bristles 14 are implanted. Multiple bristle implantation holes are drilled in the bristle implantation surface 12b, and multiple bristles 14 are implanted in the front-to-back direction in each bristle implantation hole.

The handle portion 13 has two upper and lower bulging portions 15 that bulge away from the central axis C1, and two upper and lower constricted portions 16 that constrict toward the central axis C1. Arranged from top to bottom are the upper constricted portion 16a, the upper bulging portion 15a, the lower constricted portion 16b, and the lower bulging portion 15b. The handle portion 13 also has a flange-like portion 17 above the upper constricted portion 16a that protrudes in a flange-like manner away from the central axis C1.

Figure 2 shows a perspective view of the toothbrush 11 disassembled vertically so that the head member 120 and hollow member 130 are separated. The head member 120 is combined with the hollow member 130 to form the head section 12. The hollow member 130, which is formed in a hollow cylindrical shape, is combined with the head member 120 to form the handle section 13. In this case, the tip end 131 of the hollow member 130 (described below) is located inside the head member 120 and forms part of the head section 12. When combined, the central axis C2 of the head member 120 and the central axis C3 of the hollow member 130 coincide with the central axis C1 of the toothbrush 11.

The head member 120 and hollow member 130 are formed separately. The head member 120 is a molded product, for example, by injection molding, made from various synthetic resins, including thermoplastic resins such as polypropylene (PP), saturated polyester (PET), and polyacetal (POM). Figures 3(a), (b), and (c) show a front view, a partial cross-sectional view of the right side, and a bottom view of the head member 120, respectively. An opening 121 that opens downward is provided on the lower base side of the head member 120. The opening 121 has an internal space that is approximately truncated cone-shaped and tapers in diameter toward the top. The inner peripheral portion of this internal space is called the insertion area 122. The lower end of the head member 120 has a circular outer periphery, which forms the opening edge 123, which is the outlet of the opening 121.

Figure 4(a) shows a partial cross-sectional view of the right side of the head member 120, similar to Figure 3(b). Figure 4(b) shows an enlarged view of the lower bottom side of the head member 120 in Figure 4(a). The fitted region 122 has a substantially annular undercut portion 124 that protrudes radially inward. Figure 4(c) shows an enlarged view of the undercut portion 124. The undercut portion 124 is provided around the entire inner periphery of the fitted region 122. By providing this undercut portion 124, the portion of the fitted region 122 above the undercut portion 124 forms an engagement recess 125 that is recessed radially outward and has a diameter larger than the innermost apex of the undercut 124.

The fitted region 122 also has four locking recesses 126 that are uniformly spaced circumferentially and recessed radially outward. Each locking recess 126 forms a roughly rectangular truncated space on the inside that widens toward the bottom. Each locking recess 126 has a clockwise locking surface 127a, which is an inner wall facing the clockwise direction CL in a plan view. Each locking recess 126 also has a counterclockwise locking surface 127b, which is an inner wall facing the counterclockwise direction UC in a plan view and opposite each clockwise locking surface 127a in the circumferential direction. Therefore, the fitted region 122 as a whole has four clockwise locking surfaces 127a and four counterclockwise locking surfaces 127b.

The hollow member 130 is a molded product, for example, by blow molding, made from various synthetic resins, including elastic thermoplastic resins such as low-density polyethylene (LDPE) and polypropylene (PP). Figure 5(a) shows a plan view of the hollow member 130. Figure 5(c) shows a front view of the hollow member 130. Figure 5(b) shows a side view of the hollow member 130 rotated 30° counterclockwise around the central axis C3 from the position shown in Figure 5(c). Figure 5(d) shows a cross section and a bottom view at the corresponding position in the vertical direction. The upper end of the hollow member 130 is provided with a truncated cone-shaped tip portion 131 whose diameter decreases toward the top. The outer circumferential portion from the tip portion 131 to the top of the flange portion 17, including the tip portion 131, is called the insertion region 132. The head member 120 and hollow member 130 are connected and combined by fitting the fitting region 132 into the fitted region 122. When the head member 120 and hollow member 130 are connected, the fitting region 132 is located radially inward of the opening 121 and forms part of the head portion 12.

As shown in the cross-sectional views of Figure 5(d) and the longitudinal cross-sectional view of hollow member 130 in Figure 6, hollow member 130 has a hollow structure in which the entire interior forms a single hollow space E. In other words, both tip portion 131 and flange portion 17 have a hollow structure, and the hollow space of the entire cylindrical hollow member 130 communicates with the hollow spaces of tip portion 131 and flange portion 17 to form a single hollow space E.

The hollow member 130 is formed so that its thickness is uniform throughout. This thickness is represented by the symbol t in Figure 6.

As shown in the cross-sectional views of Figure 5(d), the cross section of the hollow member 130 has a circular flange portion 17, an upper constricted portion 16a that is circular and has a smaller diameter than the flange portion 17, and the upper and lower bulging portions 15a, 15b are each formed into a roughly regular hexagon with rounded apex corners. Although not shown, the lower constricted portion 16b is also formed into a roughly regular hexagon with rounded apex corners.

Figure 7 shows an enlarged partial view of the vicinity of the tip 131 in a right side view of the hollow member 130. The fitting region 132 has a step 133 formed downward around the entire circumference midway in the vertical direction. The neck-shaped portion below this step 133 is called the neck 134. The tip 131, located above the step 133, has a diameter one step larger than the neck 134 near its lower end, forming an engagement convex portion 135 that protrudes radially outward. The diameter of the neck 134 is approximately the same as the diameter of the apex located at the innermost position of the undercut 124.

The fitting region 132 also has four locking protrusions 136 that are evenly spaced around the outer periphery of the neck portion 134 and protrude radially outward. Each locking protrusion 136 has a generally rectangular truncated shape that widens toward the bottom, and its bottom surface is integrally formed with the surface portion 138 of the flange portion 17. The surface portion 138 will be described in detail below. Each locking protrusion 136 has a clockwise locking surface 137a, which is an outer wall facing the clockwise direction CL in a plan view. It also has a counterclockwise locking surface 137b, which is an outer wall facing the counterclockwise direction UC in a plan view and is opposite each clockwise locking surface 137a in the circumferential direction. Therefore, the fitting region 132 as a whole has four clockwise locking surfaces 137a and four counterclockwise locking surfaces 137b.

The hollow member 130 has a surface portion 138 and a back surface portion 139 that constitute the flange portion 17. The upper surface portion 138 and the lower back surface portion 139 are arranged to sandwich the hollow space E inside the flange portion 17 in the vertical direction, and each is formed in a roughly annular shape, with the outer peripheries of each roughly annular shape being continuous with each other in the vertical direction. Of these, the surface portion 138 has a convex partial spherical surface whose diameter decreases as it goes upward. In other words, the surface portion 138 has a convex partial spherical surface whose diameter decreases as it goes away from the back surface portion 139.

Figure 8 shows the head member 120 and hollow member 130 in a detachably connected state. Similar to Figures 3(b) and 4(a) and (b), a partial right-side cross-sectional view of the head member 120 is shown. Similar to Figure 7, the hollow member 130 is shown with its outline as seen from the right side. To assemble the head member 120 and hollow member 130, the tip 131 is inserted upward into the opening 121. At this time, the engaging protrusion 135 elastically deforms, and its outer diameter becomes slightly smaller than the diameter of the innermost apex of the undercut 124, passing through this apex. Thus, the fitting region 132 and the fitted region 122 come into contact, and the engaging protrusion 135 and the engaging recess 125 engage with each other. Furthermore, because the undercut 124 is located below the step 133, the tip 131 is engaged upward.

When inserting the tip 131 upward into the opening 121 in this way, the angle of the tip 131 relative to the opening 121 around the central axis C1 is adjusted so that the corresponding locking protrusions 136 fit into the corresponding locking recesses 126. By combining the locking protrusions 136 with the corresponding locking recesses 126, the clockwise locking surfaces 137a face the clockwise locking surfaces 127a in the circumferential direction. Furthermore, the counterclockwise locking surfaces 137b face the counterclockwise locking surfaces 127b. As a result, the locking surfaces 137a, 137b lock the locking surfaces 127a, 127b circumferentially, preventing the head member 120 and the hollow member 130 from rotating relative to each other.

Conversely, to remove the hollow member 130 from the head member 120, the tip 131 is pulled downward through the opening 121. At this time, the engaging convex portion 135 also elastically deforms, and its outer diameter becomes slightly smaller than the diameter of the innermost apex of the undercut 124, allowing it to pass through this apex. In this way, the fitting region 132 and the fitted region 122 separate, and the engaging convex portion 135 and the engaging concave portion 125 disengage. As a result, the head member 120 and hollow member 130 are configured to be detachably connected.

When the head member 120 and hollow member 130 are connected, as shown in Figures 1(a) and 1(b) and 8, the opening edge 123 is adjacent to the flange portion 17 in the vertical direction on the surface portion 138 side.

Figures 9(a) to (c) show the state in which the head member 120 gradually tilts relative to the hollow member 130, as viewed from above the toothbrush 11. Figure 9(a) shows the state before the head member 120 tilts. Figures 9(b) and (c) show, as an example, the state in which the head member 120 tilts backward when a backward force is applied to the bristle-implanted surface 12b. When the force applied to the bristle-implanted surface 12b is released, the head member 120 returns to its original position, restoring it to the original state shown in Figure 9(a).

Furthermore, even when a force is applied to the head portion 12 in a direction other than backward, the head member 120 will tilt in that direction, as in Figures 9(b) and (c). The toothbrush 11 does not have a structure in which the amount of tilt the head member 120 can make relative to the hollow member 130, or the amount of force required to achieve that tilt, differs depending on the left-right or front-back direction, so the head member 120 can tilt freely in any direction, 360° left-right or front-back.

Figures 10(a) to (c) show the state in which the head member 120 gradually tilts relative to the hollow member 130, as viewed from the right side slightly forward of the toothbrush 11. Figure 10(a) shows the state before the head member 120 tilts. Figures 10(b) and (c) show, as an example, the state in which the head member 120 tilts when a backward force is applied to the bristle surface 12b. In other words, the angle between the central axis C2 of the head member 120 and the central axis C3 of the hollow member 130 gradually increases.

As shown in Figures 10(b) and (c), as the head member 120 tilts, the hollow member 130 elastically deforms. At this time, the rear portions of the front surface 138 and back surface 139 of the flange portion 17 are primarily crushed in the vertical direction. Conversely, the front portions of the front surface 138 and back surface 139 stretch in the front-to-rear direction. Furthermore, because the engaging convex portion 135 and the engaging concave portion 125 are engaged, the hollow member 130 will not come off the head member 120. When the applied force is released, the shape of the hollow member 130, which is made of an elastic material, returns to its original shape, and the head member 120 returns to its original position and posture.

Figures 11(a) to 11(c) are right side cross-sectional views showing the state in which the head member 120 gradually tilts relative to the hollow member 130. As shown in the figure, as the head member 120 tilts, the fitting region 132 of the hollow member 130, which is fitted into the fitted region 122 of the head member 120, also tilts. Accordingly, the flange portion 17 adjacent to the fitting region 132 tilts. Due to these tilts, the front surface portion 138 and the back surface portion 139 are squeezed toward each other at the rear because they are sandwiched between the fitting region 132 and the upper constricted portion 16a. They also stretch away from each other at the front.

At this time, when the tilt of the head member 120 is not significant, the shape of the flange portion 17 is not significantly different from the shape before deformation, and the force required to tilt the front surface portion 138 and the back surface portion 139 to maintain their original three-dimensional structure increases with the magnitude of the tilt. However, when the tilt of the head member 120 has reached a certain level, as in the state shown in Figure 11(c), the front surface portion 139 and the back surface portion 139 are in a state of approximate contact, and the original three-dimensional structure changes to a state closer to a two-dimensional structure. The inventors have discovered that the force required to further tilt at this stage is constant, regardless of the magnitude of the tilt.

With the above configuration, the toothbrush 11 is lightweight because it includes the hollow member 130 that forms the handle portion 13, and the hollow space E of the hollow member 130 is not filled with a material such as synthetic resin. Therefore, even users with weak grip strength, such as elderly people or young children, can easily operate the toothbrush 11 and clean their teeth.

In addition, because the hollow member 130 is made of an elastic material, the handle portion 13 held by the user is elastic and can cushion the force applied to areas inside the oral cavity via the head portion 12 when cleaning teeth. Moreover, because the hollow member 130 is elastically deformable, the handle portion 12 absorbs the force and returns to its original shape after being deformed. This allows the user to continue cleaning their teeth.

Furthermore, because the interior of the cylindrical portion of the hollow member 130 is connected to the interior of the flange portion 17, these simple internal structures do not significantly hinder the free deformation of the flange portion 17. For example, when a shear force is applied to the toothbrush 11 that tends to bend the upper portions of the hollow member 130, such as the tip portion 131 and neck portion 134, relative to the central axis C1 of the toothbrush 11, the inner portion of the flange portion 17 that tends to bend is compressed, while the outer portion that tends to bend is stretched. As a result, when the shear force is applied, the portion of the hollow member 130 above the flange portion 17 can tilt in either direction relative to the portion below the flange portion 17. Furthermore, the head member 120 can swing freely relative to the hollow member 130.

The head member 120 can tilt in any direction, allowing the user to evenly apply the bristles to each part of the oral cavity for cleaning. For example, if the head member 120 could only tilt in a fixed direction, only part of the bristles 14 might reach the teeth. In contrast, the toothbrush 11 allows the entire bristles 14 to be applied in any direction or angle, resulting in a high cleaning effect. Furthermore, even if a small child or elderly person falls while holding the head member in their mouth, the head member 120 can tilt in any direction, allowing the toothbrush 11 to absorb impacts from all directions when the toothbrush 11 falls, reducing the risk of the head member 12 poking the user's throat and causing injury.

Due to this structure, the degree to which the head member 120 can freely tilt relative to the hollow member 130, i.e., the hardness of the entire toothbrush 11, can be easily adjusted by adjusting the thickness, shape, material, and other components of the flange portion 17 during manufacturing. In this way, the toothbrush 11 can cushion the force applied by the bristles 14 to areas inside the mouth when cleaning teeth to a degree that does not injure the inside of the user's mouth, and the degree of cushioning can be easily adjusted when manufactured.

Furthermore, because the hollow member 130 has an internal structure in which the inside of the cylindrical portion and the inside of the flange portion 17 are connected, when the material is synthetic resin, the entire member can be molded as a single unit, and it can be manufactured simply and efficiently by using a manufacturing method such as blow molding.

Next, when the user presses the bristles 14 against an area in the mouth to clean their teeth, the head member 120 transmits the recoil force received from that area to the hollow member 130 connected to the head member 120. When this recoil force generates a shear force that bends the hollow member 130, this shear force is transmitted through the opening of the head member 120 to the hollow member 130. At this time, because the opening edge 123 and the flange 17 of the toothbrush 11 are adjacent, the shear force is efficiently transmitted to the flange 17. The hollow member 130 absorbs the shear force by elastically deforming, crushing the inner portion of the flange 17 that is about to bend and stretching the outer portion that is about to bend. Furthermore, because the shear force is efficiently transmitted to the flange portion 17, the degree to which the hollow member 130 buffers the shear force can be easily adjusted by adjusting the thickness, shape, material, and other configurations of the flange portion 17. In this way, the toothbrush 11 is able to buffer the force applied by the bristles 14 to areas inside the oral cavity when cleaning teeth to an extent that does not damage the inside of the user's oral cavity, and the degree of buffering can be easily adjusted when manufactured.

Next, the toothbrush 11 has an elastically deformable handle 13 and a bulge 15, allowing the user to grasp the thick bulge 15 with their fingers or their fingers and palm, making it easy for even the elderly and young children with weak grip strength to support the toothbrush 11. Furthermore, the handle 13 is made of a hollow member 130 with a hollow structure, making it soft, allowing even users with weak grip strength to firmly grip the hollow bulge 15. Therefore, there is little risk of the toothbrush 11 falling from their hands while cleaning their teeth.

Furthermore, because the toothbrush 11 has a constricted portion 16, the user can place their fingers against the constricted portion 16 to stabilize and support the toothbrush 11 when cleaning their teeth. In particular, because the upper constricted portion 16a is located between the flange portion 17 and the upper bulging portion 15a, the user can, for example, place their index finger against the upper constricted portion 16a and their middle and ring fingers against the bulging portions 15a and 15b, allowing the index finger to control the position, angle, etc. of the head portion 12 while the middle and ring fingers, etc., can securely grip the handle portion 13. In this way, the toothbrush 11 can be used to clean teeth efficiently.

Secondly, because the head member 120 and hollow member 130 are detachably connected, either the head member 120 or the hollow member 130 of the toothbrush 11 can be replaced. Therefore, for example, it is possible to discard only one of the head member 120 and hollow member 130 and continue to use the other, eliminating waste and minimizing the burden on the global environment.

In addition, the head member 120 can be separated from the hollow member 130 and then reattached to the hollow member 130. This allows the user to remove the head member 120 to expose the insertion area 132 and the inserted area 122 for cleaning. This allows the toothbrush 11 to be kept clean at all times.

Furthermore, because the engaging convex portion 135 and the engaging concave portion 125 of the toothbrush 11 engage with each other, there is little risk of the head member 120 coming off the hollow member 130, even while cleaning your teeth. This prevents accidents such as choking on the head member 120, allowing for safe use.

Furthermore, because the toothbrush 11 has engaging surfaces 137a, 137b and engaged surfaces 127a, 127b, rotation of the head member 120 about the central axis C2 relative to the hollow member 130 is prevented. Therefore, even though the head member 120 is detachably attached to the hollow member 130, the head member 120 does not rotate, even when the user is gripping the handle portion 13 to clean their teeth. This allows the user to efficiently clean their teeth by keeping the bristles 14 in a specified orientation.

Finally, because the flange portion 17 is substantially circular when viewed from the direction of the central axis C3, linear mountain or valley folds such as those in a square or polygonal shape are not formed in the flange portion 17. As a result, the direction of deformation when force is applied is less likely to be limited to a specific direction, as is the case when linear mountain or valley folds are formed. This allows the flange portion 17 to easily deform in various directions, and because it has few corners, it can deform flexibly.

This allows the head member 120 of the toothbrush 11 to tilt in any direction, and also makes it easier to cushion the forces applied to areas inside the oral cavity.

In addition, because the surface portion 138 of the flange portion 17 of the toothbrush 11 has a convex, partially spherical surface, the portion of the hollow member 130 above the flange portion 17 tilts, causing the surface portion 138 and the back surface portion 139 to collapse toward each other. The inventors discovered that when the force applied to cause the tilt exceeds a certain tilt (amount of deformation), the force becomes constant. Therefore, even if a force greater than the certain level is accidentally applied to the toothbrush 11 while cleaning the oral cavity, the toothbrush 11 can adequately cushion the force. In this way, the structure of the toothbrush 11 of the present invention makes it easy to adjust the degree to which the force is cushioned by adjusting the thickness, shape, material, and other configurations of the flange portion 17 during manufacturing.

[Example]
The inventors measured the bending strength of the toothbrush 11 of the present invention. Figures 12(a) and 12(b) show photographs of the apparatus used for the measurement. The inventors prepared a toothbrush 11 without bristles 14 attached, and held the toothbrush 11 cantilevered by clamping the hollow member 130 vertically with clamp C in the vertical direction of the photograph, so that the central axis C1 of the toothbrush 11 was aligned with the horizontal and the bristle surface 12b was facing upward. Using a bending strength measuring device with an indenter I at its tip, the indenter I was lowered at a rate of 100 mm per minute while contacting the bristle surface 12b, and the load applied to the indenter I was measured. The maximum distance the indenter I descended was set to 25 mm. The load was measured in Newtons (N). Figure 12(a) shows the state before the indenter I was lowered, and Figure 12(b) shows the state after the indenter I had been lowered 25 mm.

The toothbrush 11 of the present invention used in this example has a total length L in the vertical direction, as shown in Figure 13, of 183.5 mm. The inventors set the protruding length L1, which is the distance between the top end of the toothbrush 11 and the end of the clamp C closest to the top end of the toothbrush 11, to 80.0 mm. The toothbrush 11 has a head length L2, which is the length of the head portion 12 from the top end to the opening edge 123, of 71.8 mm. As a result, the handle protruding length L3, which is the protruding length of the handle portion 13, was 8.2 mm.

In addition, the toothbrush 11 of this embodiment uses polypropylene (PP) as the material for both the head member 120 and the hollow member 130. The hollow structure of the hollow member 130 is formed with a uniform wall thickness t of 0.4 mm, as shown in Figure 6.

On the other hand, the inventors prepared a toothbrush without a hollow structure as Comparative Example 1 for comparison with this example. Like toothbrush 11 of this example, the toothbrush of Comparative Example 1 was also measured by holding it with clamp C so that the protruding length L1 was 80.0 mm. Polypropylene (PP) was used as the material for the toothbrush of Comparative Example 1.

By lowering the indenter I, the head member 120 of the toothbrush 11 tilted backward relative to the hollow member 130. As the head member 120 tilted, the upper end of the toothbrush 11 moved backward. The distance the upper end moved backward is called the deformation distance d, and the deformation distance d of the toothbrush 11 of this example when it was lowered was measured. The deformation distance d of Comparative Example 1 was also measured in the same way as in this example.

Graph A in Figure 14 shows the load (N) applied to the indenter I at each deformation distance d when the indenter I is lowered at a constant speed of 100 mm/min for the toothbrush 11 of this embodiment. The horizontal axis represents the deformation distance d in mm, and the vertical axis represents the load (N). Graph B also shows the load (N) applied to the indenter I at each deformation distance d for Comparative Example 1.

As shown in graph B, with the toothbrush of Comparative Example 1, the load applied to the indenter I increases almost proportionally as the deformation distance d increases. In contrast, as shown in graph A, with the toothbrush 11 of this example, the load increased in proportion to the deformation distance d immediately after deformation began, but thereafter remained flat even as the deformation distance d increased. Furthermore, the magnitude of the load itself with the toothbrush 11 of this example was smaller than with the toothbrush of Comparative Example 1.

From these findings, the inventors discovered that toothbrush 11 applies a smaller load to indenter I in response to external forces, and that its ability to buffer these forces is therefore greater than that of the toothbrush in Comparative Example 1. They also discovered that as the load applied to toothbrush 11 increases to a certain extent, once a certain deformation distance d, or a certain inclination, is exceeded, the deformation no longer increases and remains constant. In this way, they discovered that once a certain inclination (amount of deformation) is exceeded, the force applied to create that inclination becomes constant.

Second Embodiment
A second embodiment of the present invention will be described with reference to FIG. 15 . In the front view of FIG. 15 , reference numeral 21 denotes a toothbrush having a head portion 22 at the distal end and a handle portion 23 that is gripped to guide the head portion 22 into the oral cavity. Bristles 24 are attached to the head portion 22. The handle portion 23 has two upper and lower bulging portions 25 that bulge away from the central axis C1 of the toothbrush 21, and also has two upper and lower constricted portions 26 that constrict toward the central axis C1. Arranged from top to bottom are the upper constricted portion 26a, the upper bulging portion 25a, the lower constricted portion 26b, and the lower bulging portion 25b. The handle portion 23 also has a flange-like portion 27 above the upper constricted portion 26a that protrudes away from the central axis C1.

The head portion 22 and handle portion 23 are composed of a head member 220 and a hollow member 230, which are formed separately. The head member 220 forms the head portion 22 when combined with the hollow member 230. The hollow member 230, which is formed in a hollow cylindrical shape, forms the handle portion 23 when combined with the head member 220. The hollow member 230 has a hollow structure in which the entire interior forms a single hollow space E.

The hollow member 230 has a surface portion 238 and a back surface portion 239 that constitute the flange portion 27. The upper surface portion 238 and the lower back surface portion 239 are arranged to sandwich the intermediate space E inside the flange portion 27 in the vertical direction, and each is formed in a roughly annular shape, with the outer peripheries of each roughly annular shape being continuous with each other in the vertical direction. Of these, the surface portion 238 has an inclined surface whose diameter decreases upward. In other words, the surface portion 238 has an inclined surface whose diameter decreases the further away it is from the back surface portion 239.

The rest of the configuration is the same as in the first embodiment.

As described above, the toothbrush 21 has an inclined surface on the surface portion 238 of the flange portion 27. As with the first embodiment, in which the surface portion 138 has a partially spherical convex surface, the portion of the hollow member 230 above the flange portion 27 tilts, causing the surface portion 238 and the back surface portion 239 to collapse toward each other. The inventors discovered that when the force applied to cause the tilt exceeds a certain tilt (deformation amount), the force becomes constant. Therefore, even if a force greater than the certain level is accidentally applied to the toothbrush 21 while cleaning the oral cavity, the toothbrush 21 can adequately cushion the force. Thus, the structure of the toothbrush 21 of the present invention allows the degree of cushioning of the applied force to be easily adjusted by adjusting the thickness, shape, material, and other configurations of the flange portion 27 during manufacturing.

[Third embodiment]
A third embodiment of the present invention will be described with reference to FIG. 16 . In the partial front view of FIG. 16 , reference numeral 31 denotes a toothbrush having a head portion 32 at the distal end thereof and a handle portion 33 that is gripped to guide the head portion 32 into the oral cavity. Bristles 34 (not shown) are attached to the head portion 32. The handle portion 33 has two upper and lower bulging portions 35 that bulge away from the central axis C1 of the toothbrush 31, and also has two upper and lower constricted portions 36 that constrict toward the central axis C1. Of these, only the upper constricted portion 36a is shown. Furthermore, the handle portion 33 has a two-tiered flange portion 37 above the upper constricted portion 36a that protrudes in a flange-like manner away from the central axis C1. The upper flange portion 37a and the lower flange portion 37b are arranged in order from top to bottom.

The hollow member 330 has a hollow structure in which the entire interior forms a single hollow space E. In other words, the upper and lower flanges 37a, 37b each have a hollow structure, and the hollow space of the entire cylindrical hollow member 330 communicates with each of the flanges 37a, 37b to form a single hollow space E.

The hollow member 330 has an upper surface portion 338a, an upper back surface portion 339a, and a lower surface portion 338b and back surface portion 338b, which respectively constitute the flange portions 37a and 37b. In each of the upper and lower stages, the upper surface portions 338a and 338b and the lower back surface portions 339a and 339b are arranged to sandwich the hollow space E inside each flange portion 37a and 37b in the vertical direction. Each of these surfaces is formed in a generally annular shape, and the outer peripheries of each generally annular shape are formed continuously with each other in the vertical direction. Each of these surface portions 338a and 338b has an inclined surface whose diameter decreases upward. In other words, the upper surface portion 338a has an inclined surface whose diameter decreases as it moves away from the upper back surface portion 339a. Additionally, the lower surface portion 338b has an inclined surface whose diameter decreases as it moves away from the lower back surface portion 339b.

Furthermore, the upper back surface portion 339a has an inclined surface that tapers downward. In other words, the upper back surface portion 339a has an inclined surface that tapers the further away from the upper front surface portion 338a.

The rest of the configuration is the same as in the second embodiment.

As described above, because the toothbrush 31 has two-tiered flanges 37a, 37b, the degree of cushioning of applied force can be adjusted over a wider range than when it has only a single flange, by adjusting the thickness, shape, material, and other configurations of each flange 37a, 37b during manufacturing. Also, while Figure 16 shows an embodiment in which the outer diameter of the upper flange 37a and the outer diameter of the lower flange 37b are approximately the same, the degree of cushioning of applied force can also be adjusted over a wider range by making the upper and lower flanges different dimensions.

[Fourth embodiment]
A fourth embodiment of the present invention will be described with reference to Fig. 17. In Fig. 17(a) as a front view and Fig. 17(b) as a right side view, reference numeral 41 denotes a toothbrush. The toothbrush 41 has a head portion 42 at the tip end thereof and a handle portion 43 that is gripped to guide the head portion 42 into the oral cavity. Bristles 44 are attached to the head portion 42.

The toothbrush 41 is made up of an upper head member 420 and a lower hollow member 430 that are combined together. The head member 420 forms the head section 42 when combined with the hollow member 430. The hollow member 430, which is formed into a hollow cylinder, forms the handle section 43 when combined with the head member 420. In this case, the tip 431 of the hollow member 430 is located inside the head member 420 and forms part of the head section 42. The central axis C2 of the head member 420 and the central axis C3 of the hollow member 430 coincide with the central axis C1 of the toothbrush 41 when combined.

The head member 420 and hollow member 430 are formed separately. Figure 18 shows a partial cross-sectional plan view of the head member 420 and a partial plan view of the hollow member 430 when the head member 420 and hollow member 430 are combined. An opening 421 that opens downward is provided on the lower base side of the head member 420. The opening 421 has an upper cylindrical internal space and a lower cylindrical internal space that communicates with the upper internal space and has a larger diameter than the upper internal space. The inner peripheral portion of this combined internal space is called the insertion area 422. The lower end of the head member 420 has a circular outer periphery that forms the opening edge 423, which is the outlet of the opening 421.

The insertion region 422 has a female thread portion 425 on the inner circumferential portion of the upper internal space. In the female thread portion 425, the head member 420 has a thread groove 425a recessed radially outward. The thread groove 425a forms a spiral around the central axis C2 of the head member 420.

The hollow member 430 has a male thread 435 on the outer periphery of the tip 431. The male thread 435 has a thread 435a that protrudes radially outward. The thread 435a forms a spiral around the central axis C3 of the hollow member 430. The outer periphery from the tip 431 to the top of the flange 47, including the tip 431, is called the fitting region 432. The head member 420 and hollow member 430 are combined by threading the female thread 425 and the male thread 435 together and fitting the fitting region 432 into the fitted region 422 to connect them together.

The rest of the configuration is the same as the first or second embodiment.

With the above configuration, the head member 420 and hollow member 430 are detachably connected, allowing either the head member 420 or the hollow member 430 of the toothbrush 41 to be replaced. The head member 420 can also be separated from the intermediate member 430 and then reattached to the intermediate member 430. Furthermore, because the male threaded portion 435 and the female threaded portion 425 of the toothbrush 41 are threaded together, there is little risk of the head member 420 coming off the hollow member 430, even while cleaning your teeth, for example.

The above describes exemplary embodiments of the present invention, but the present invention is not limited to these embodiments, and various modifications are possible without departing from the spirit of the present invention.

For example, the material of the head member is not limited to polypropylene (PP), saturated polyester (PET), polyacetal (POM), etc., but may be any other synthetic resin or material other than synthetic resin, as long as it can accommodate bristles and is strong enough to withstand tooth brushing. It may also be formed by a manufacturing method other than injection molding.

The material for the hollow member is not limited to low-density polyethylene (LDPE), polypropylene (PP), etc., but may be any other synthetic resin or material other than synthetic resin, as long as it can be formed hollow, has elasticity, and is strong enough to support the head member. It may also be formed by a manufacturing method other than blow molding.

The cross section or lower end of the head member may be formed in a shape other than circular, and the cross section of the hollow member may be formed in a shape other than circular or approximately regular hexagonal. The cross section of the head member may be, for example, polygonal, as long as it can accommodate the joining structure with the hollow member. Furthermore, the cross section of the hollow member may be, for example, polygonal, other than hexagonal, polygonal, other than regular, etc., as long as it can be easily gripped with the fingers and palm.

The thickness of the hollow member does not have to be uniform throughout, and as long as the handle is elastic, the head can tilt freely, and the toothbrush has the necessary strength, it can be uneven.

The engagement recess and engagement protrusion do not have to be a recess and a protruding portion with a larger diameter, respectively, as exemplified in the first embodiment. For example, the engagement recess could be groove-shaped and the engagement protrusion could be ring-shaped so that it fits into the groove, as long as it can reliably and detachably connect the head member and hollow member.

If the head member and hollow member are configured to be removably and securely connected, even if the engaging recess is provided on the head member and the engaging protrusion is not provided on the hollow member, the engaging recess may instead be provided on the hollow member and the engaging protrusion on the head member.

Regarding the locked recessed portion, locking protrusion, locked surface, and locking surface, the recessed portion provided on the head member is referred to as the locked recessed portion and locked surface, and the protrusion provided on the hollow member is referred to as the locking protrusion and locking surface. However, these are names used for convenience of distinction; for example, the recessed portion could be referred to as the locking recessed portion and locking surface, and the protrusion could be referred to as the locked protrusion and locked surface. Furthermore, as long as it is possible to prevent relative rotation between the head member and the rotating member, for example, the protrusion could be provided on the head member side and the recessed portion on the hollow member side.

The arrangement of the partial spherical surface or inclined surface on the flange-shaped portion is not limited to the examples given in the first to fourth embodiments. As long as the head member can freely swing relative to the hollow member, for example, the rear surface may have a convex partial spherical surface that tapers downward, or the rear surface may have an inclined surface that tapers downward. Furthermore, both the front and rear surfaces may have these partial spherical surfaces or inclined surfaces, and one of the front and rear surfaces may have a partial spherical surface and the other an inclined surface.

The shape of the flange in plan view does not have to be circular; it may be, for example, an ellipse, an oval, or a polygon with rounded vertices, as long as it minimizes interference with tilting of the head member relative to the hollow member.

The flange-shaped portion does not have to be limited to a one-stage or two-stage configuration; it may be, for example, a three-stage or four-stage or more-stage configuration, as long as it can absorb forces applied to a region within the oral cavity, deform, and then restore itself to its original shape.

The head does not have to be shaped to taper gradually upwards, or to taper gradually from the middle in the vertical direction as in the fourth embodiment. For example, it may have a two-stage shape with a smaller diameter halfway down, as shown in the partial plan view of Figure 19, as long as it does not adversely affect the weight balance when cleaning teeth.

Disclose the following:
(Claim 1)
a head member constituting a head portion in which bristles are planted at the tip side;
a hollow member that is connected to the head member, forms a handle portion that is gripped to guide the head member into the oral cavity, and is hollow and tubular and made of an elastic material;
The hollow member has a flange-like portion that protrudes in a direction away from the central axis thereof,
The flange-shaped portion is formed hollow, and the interior thereof communicates with the interior of the hollow cylindrical portion,
The toothbrush is characterized in that, at the connecting portion between the head member and the hollow member, one has an engaging surface arranged to face in the circumferential direction of the central axis, and the other has an engaging surface arranged to face in the opposite direction to the engaging surface in the circumferential direction.
(Claim 2)
the head member has an opening on the proximal end side,
The tip of the hollow member is inserted into the opening,
The toothbrush according to claim 1 , wherein the opening edge of the opening and the flange of the hollow member are adjacent to each other in the direction of the central axis.
(Claim 3)
The toothbrush according to claim 1, wherein the handle portion has a bulging portion that bulges out in a direction away from the central axis in a portion other than the flange portion.
(Claim 4)
The toothbrush according to claim 3, wherein the handle portion has a narrowed portion between the flange portion and the bulging portion that narrows in a direction approaching the central axis.
(Claim 5)
the head member has an opening on the proximal end side,
The tip of the hollow member is fitted into the opening,
either the insertion region of the tip of the hollow member or the inserted region of the opening, both of which are the connecting portion, has an engagement convex portion that protrudes in a direction away from the central axis,
the other of the fitting region and the fitted region has an engaging recessed portion recessed in the away direction,
The engagement convex portion and the engagement concave portion are engaged with each other,
5. The toothbrush according to claim 1, wherein the head member and the hollow member are configured to be detachably connected to each other.
(Claim 6)
The engaging surface is provided in one of the fitting area and the fitted area, and the engaging surface is provided in the other of the fitting area and the fitted area;
The toothbrush according to claim 5, wherein the head member and the hollow member are prevented from rotating relative to each other by the engaging surface engaging the engaged surface in the circumferential direction.
(Claim 7)
The toothbrush according to any one of claims 1 to 6, wherein the flange portion is formed in a substantially circular shape when viewed in the direction of the central axis.
In addition, the following items shall be disclosed:
[Claim 1]
a head member constituting a head portion in which bristles are planted at the tip side;
a hollow member that is connected to the head member, forms a handle portion that is gripped to guide the head member into the oral cavity, and is hollow and tubular and made of an elastic material;
The hollow member has a flange-like portion that protrudes in a direction away from the central axis thereof,
The flange-shaped portion is formed hollow, and the interior thereof communicates with the interior of the hollow cylindrical portion,
At the base end portions of the connecting portions of the head member and the hollow member, one has an engaged surface provided so as to face in the circumferential direction of the central axis, and the other has an engaging surface provided so as to face in the opposite direction to the engaged surface in the circumferential direction,
The head member has an opening of the connecting portion having an internal space with a generally truncated cone shape whose diameter decreases toward the back,
The hollow member has a locking surface or a locked surface that is continuous with the flange-shaped portion, and the tip of the connecting portion has a truncated cone shape that decreases in diameter toward its tip end.
A toothbrush characterized by:
[Claim 2]
the head member has an opening on the proximal end side,
The tip of the hollow member is inserted into the opening,
The opening edge of the opening and the flange portion of the hollow member are adjacent to each other in the direction of the central axis.
2. The toothbrush of claim 1.
[Claim 3]
The handle portion has a bulging portion that bulges away from the central axis in a portion other than the flange-shaped portion.
2. The toothbrush of claim 1.
[Claim 4]
The handle portion has a narrowed portion between the flange portion and the bulging portion, the narrowed portion being narrowed in a direction approaching the central axis.
4. The toothbrush of claim 3.
[Claim 5]
The head member has an opening on the proximal end side,
The tip of the hollow member is fitted into the opening,
either the insertion region of the tip of the hollow member or the inserted region of the opening, both of which are the connecting portion, has an engagement convex portion that protrudes in a direction away from the central axis,
the other of the fitting region and the fitted region has an engaging recessed portion recessed in the away direction,
The engagement convex portion and the engagement concave portion are engaged with each other,
The head member and the hollow member are configured to be detachably connected to each other.
5. The toothbrush according to claim 1, wherein the toothbrush is made of a material having a thickness of 100 nm or less.
[Claim 6]
The engaging surface is provided in one of the fitting area and the fitted area, and the engaging surface is provided in the other of the fitting area and the fitted area;
The engaging surface engages the engaged surface in the circumferential direction, whereby the head member and the hollow member are prevented from rotating relative to each other.
6. The toothbrush of claim 5.
[Claim 7]
The flange portion is formed in a substantially circular shape when viewed in the direction of the central axis.
7. The toothbrush according to claim 1, wherein the toothbrush is made of a material having a thickness of 100 nm or less.

The present invention can be used in toothbrushes that clean a user's teeth with embedded bristles.

11, 21, 31, 41 Toothbrush 12, 22, 32, 42 Head portion 13, 23, 33, 43 Handle portion 14, 24, 34, 44 Bristles 15, 25, 35 Bulging portion 16, 26, 36 Narrowed portion 17, 27, 37, 47 Flange-shaped portion 120, 220, 320, 420 Head member 121, 421 Opening 122, 422 Fitting area 123, 423 Opening edge 124 Undercut portion 125 Engaging recessed portion 126 Engaging recessed portion 130, 230, 330, 430 Hollow member 131, 431 Tip portion 132, 432 Fitting area 133 Step 135 Engaging convex portion 136 Engaging convex portion 138, 238, 338 Surface portion 139, 239, 339 Back surface portion 425 Female thread portion 435 Male thread portion

Claims (7)

a head member constituting a head portion in which bristles are planted at the tip side;
a hollow member that is connected to the head member, forms a handle portion that is gripped to guide the head member into the oral cavity, and is hollow and tubular and made of an elastic material;
The hollow member has a flange-like portion that protrudes in a direction away from the central axis thereof,
The flange-shaped portion is formed hollow, and the interior thereof communicates with the interior of the hollow cylindrical portion,
At the base end portions of the connecting portions of the head member and the hollow member, one has an engaged surface provided so as to face in the circumferential direction of the central axis, and the other has an engaging surface provided so as to face in the opposite direction to the engaged surface in the circumferential direction,
The head member has an opening of the connecting portion having an internal space with a generally truncated cone shape whose diameter decreases toward the back,
The hollow member has the locking surface or the locked surface that is continuous with the flange-shaped portion, and the tip of the connecting portion forms a truncated cone shape whose diameter decreases toward its tip end.
A toothbrush characterized by:
the head member has an opening on the proximal end side,
The tip of the hollow member is inserted into the opening,
The toothbrush according to claim 1 , wherein the opening edge of the opening and the flange of the hollow member are adjacent to each other in the direction of the central axis.
The toothbrush according to claim 1, wherein the handle portion has a bulging portion that bulges out in a direction away from the central axis in a portion other than the flange portion.
The toothbrush according to claim 3, wherein the handle portion has a narrowed portion between the flange portion and the bulge portion that narrows in a direction approaching the central axis.
the head member has an opening on the proximal end side,
The tip of the hollow member is fitted into the opening,
one of the insertion region of the tip of the hollow member and the inserted region of the opening, both of which are the connecting portion, has an engagement convex portion that protrudes in a direction away from the central axis,
the other of the fitting region and the fitted region has an engaging recessed portion recessed in the away direction,
The engagement convex portion and the engagement concave portion are engaged with each other,
5. The toothbrush according to claim 1, wherein the head member and the hollow member are configured to be detachably connected to each other.
The engaging surface is provided in one of the fitting area and the fitted area, and the engaging surface is provided in the other of the fitting area and the fitted area;
The toothbrush according to claim 5, wherein the head member and the hollow member are configured to be prevented from rotating relative to each other by the engaging surface engaging the engaged surface in the circumferential direction.
The toothbrush according to any one of claims 1 to 6, wherein the flange portion is formed in a substantially circular shape when viewed in the direction of the central axis.