Toothbrush

Abstract

To provide a toothbrush that has a hollow structure, can buffer a force to be applied by bristles to an oral cavity site to a degree at which the oral cavity of a user is not damaged during cleaning the teeth, and can be produced by easily adjusting a degree of buffering.SOLUTION: A toothbrush comprises: a head member constituting a head part having bristles implanted at the tip side; and a hollow member connected to the head member, constituting a handle part gripped so as to guide the head part into the oral cavity, having a hollow cylindrical shape, and formed of an elastic material. The hollow member has a flange-like portion projecting in a flange shape in a direction of receding from a center axis line. The flange-like portion is formed in a hollow shape, and has an inside communicated with the inside of the hollow cylindrical part. Of the head member and the hollow member, one has a locked surface and the other has a locking surface at a connection part of them.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The present invention relates to a toothbrush, and more particularly to a toothbrush including a head portion having bristles implanted on the tip side and a handle portion that is gripped to guide the head portion into the oral cavity.

Background Art

[0002] Conventionally, there has been a toothbrush having a hollow structure in which a part of the shaft portion is formed in a hollow cylindrical shape (Patent Document 1). Such a conventional hollow-structured toothbrush is relatively lightweight because the hollow portion is not filled with a material such as synthetic resin that forms the portion other than the hollow portion.

[0003] Further, by changing the dimensions of the hollow portion, the degree of deflection of the shaft portion can be adjusted. That is, when the hollow portion is elongated in the longitudinal direction of the shaft portion, by changing the length of the hollow portion and the position in the longitudinal direction, the hardness when cleaning teeth can be adjusted, and the force applied by the bristles to the site in the oral cavity can be buffered.

[0004] Thus, the conventional hollow-structured toothbrush can be used lightly, and moreover, since the hardness when cleaning teeth can be adjusted, it can meet various needs such as the strength of the user's physical strength and the intensity when cleaning.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the conventional toothbrush with a hollow structure, the hollow portion is formed in a substantially cylindrical shape and extends straight along the longitudinal direction of the toothbrush. Thus, when a shearing force that bends the head portion side and the handle portion side is applied to the toothbrush when trying to apply force to the bristles, the straight portion is vulnerable to the shearing force and is likely to bend at the location where the force is concentrated. Alternatively, if the strength is increased so as not to bend in this way, the bristles cannot sufficiently buffer the force applied to the site in the oral cavity.

[0007] Also, when the toothbrush bends halfway in this way, the bent portion may damage the user's oral cavity. And once bent, it does not easily return to its original shape, and the toothbrush cannot be continuously used.

[0008] Therefore, an object of the present invention is to provide a toothbrush having a hollow structure, capable of buffering the force applied by the bristles to the site in the oral cavity so as not to damage the user's oral cavity when cleaning teeth, and moreover, capable of easily adjusting the degree of buffering and manufacturing.

Means for Solving the Problems

[0009] (1) The present invention includes a head member constituting a head portion where bristles are implanted on the tip side, a handle portion connected to the head member and gripped for guiding the head portion into the oral cavity, a hollow cylindrical member formed of an elastic material, and the hollow member has a flange-shaped portion protruding in a flange shape in a direction away from its central axis, the flange-shaped portion is formed hollow, and its interior communicates with the interior of the hollow cylindrical portion. The present invention provides a toothbrush characterized by this. Further, this flange-shaped portion is formed substantially circular in a view in the central axis direction, and has a substantially annular front surface portion and a substantially annular back surface portion disposed opposite to sandwich the interior in the central axis direction, and at least one of the front surface portion and the back surface portion may have an inclined surface that reduces in diameter as it moves away from the other of the front surface portion and the back surface portion, or a convex partial spherical surface that also reduces in diameter.

[0010] That is, the toothbrush of the present invention includes a hollow member that constitutes the handle portion, and since the inside of the hollow member is not filled with a material such as synthetic resin, it is lightweight. Therefore, even a user with weak grip strength, such as an elderly person or an infant, can easily clean their teeth by operating the toothbrush of the present invention.

[0011] In addition, since the hollow member is formed of an elastic material, the handle portion gripped by the user has elasticity and can buffer the force applied to the site in the oral cavity via the head portion when cleaning the teeth. Moreover, since the hollow member is elastically deformed, the handle portion can absorb the force and deform, and then restore itself to its original shape. Therefore, the user can continue to clean their teeth thereafter.

[0012] Furthermore, the inside of the cylindrical portion and the inside of the flange portion communicate with each other, and due to their simple internal structures, the free deformation of the flange portion is rarely hindered. For example, when a shearing force that bends the hollow member on the head portion side with respect to the central axis of the toothbrush is applied to the toothbrush, the inner portion of the flange portion where the head portion side tends to bend is compressed, and the outer portion that tends to bend can extend. As a result, when the shearing force is applied, the side of the hollow member closer to the head portion than the flange portion can tilt in any direction with respect to the side opposite to the head portion than the flange portion. And the head member can freely swing with respect to the hollow member.

[0013] When the head member tilts in a free direction, the user can evenly apply the bristles to each part in the oral cavity for cleaning. For example, when the head member can only tilt in a fixed direction, only a part of the bristles may hit. In contrast, the toothbrush of the present invention can apply the entire bristles in a free direction, angle, etc., and has a high cleaning effect. Also, even if infants, the elderly, etc. fall while holding the head part, since the head member tilts in a free direction, the toothbrush of the present invention can buffer the impact from all directions during the fall, and there is little risk that the head part will pierce and injure the user's throat.

[0014] As described above, by adjusting the configuration such as the thickness, shape, material, etc. of the flange portion during manufacturing, the degree to which the head member can freely tilt with respect to the hollow member, that is, the hardness of the entire toothbrush can be easily adjusted. In this way, the toothbrush of the present invention can buffer the force applied by the bristles to the parts in the oral cavity so as not to damage the user's oral cavity when cleaning the teeth, and moreover, the degree of buffering can be easily adjusted and manufactured.

[0015] Also, since the hollow member has an internal structure in which the inside of the cylindrical portion and the inside of the flange portion communicate with each other, when the material is a synthetic resin, it can be integrally molded as a whole, and can be manufactured simply and efficiently by adopting a manufacturing method such as blow molding.

[0016] (2) Further, the head member may have an opening on the proximal 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 central axis direction.

[0017] That is, when the user presses a part in the oral cavity with the bristles to clean the teeth, the head member transmits the reaction force received from this part to the hollow member connected to the head member. And when a shearing force that bends the hollow member is generated by the reaction force, this shearing force is transmitted from the opening of the head member to the hollow member. At this time, in the toothbrush of the present invention, since the opening edge of the opening and the flange-like part of the hollow member are adjacent to each other, the shearing force is efficiently transmitted to the flange-like part.

[0018] By the way, the hollow member buffers the shearing force by elastically deforming such that the inner part where the flange-like part tends to bend is crushed and the outer part where it tends to bend extends. And since the shearing force is efficiently transmitted to the flange-like part, the hollow member can easily adjust the degree of buffering the shearing force by adjusting the configuration such as the thickness, shape, and material of the flange-like part. Thus, the toothbrush of the present invention can buffer the force applied by the bristles to the part in the user's oral cavity so as not to damage the oral cavity when cleaning the teeth, and moreover, can be easily adjusted in terms of the degree of buffering and manufactured.

[0019] (3) Further, the handle part may have a bulging part that bulges in a direction away from the central axis at a part other than the flange-like part.

[0020] That is, since the toothbrush of the present invention has a handle part that is elastically deformable and has a bulging part, when the user grips the thick bulging part with a finger or fingers and palm, even a person with a weak grip strength such as an elderly person or an infant can easily support the toothbrush. Moreover, since the handle part is constituted by a hollow member, it is soft, and even a user with a weak grip strength can firmly grip the hollow bulging part. Therefore, the toothbrush of the present invention has little risk of falling out of the hand during tooth cleaning.

[0021] (4) Further, the handle part may have a constricted part that constricts in a direction approaching the central axis between the flange-like part and the bulging part.

[0022] That is, since the toothbrush of the present invention has a constricted portion, when the user places a finger on this constricted portion, the posture of the toothbrush can be stabilized and supported when cleaning the teeth. In particular, since the constricted portion is provided between the flange portion and the bulging portion, the user can, for example, place the index finger on the constricted portion and the middle finger, ring finger, etc. on the bulging portion, so that while the index finger controls the position, angle, etc. of the head portion, the middle finger, ring finger, etc. can securely grip the handle portion. Thus, efficient tooth cleaning can be performed with the toothbrush of the present invention.

[0023] (5) Further, the tip of the hollow member is fitted into the opening, and either one of the fitting region of the tip of the hollow member and the fitted region of the opening has an engaging convex portion protruding in a direction away from the central axis, and the other of the fitting region and the fitted region has an engaging concave portion recessed in the away direction, and the engaging convex portion and the engaging concave portion are engaged, and the head member and the hollow member may be configured to be detachably connected.

[0024] That is, since the head member and the hollow member are detachably connected, the toothbrush of the present invention can replace either the head member or the hollow member. Therefore, for example, only one of the head member and the hollow member can be discarded and the rest can be continuously used without waste, and the load on the global environment is small.

[0025] Also, the head member can be separated from the hollow member and then attached to the hollow member again. Therefore, the user can remove the head member to expose the fitting region and the fitted region for cleaning. Thereby, the toothbrush of the present invention can always be kept clean.

[0026] Moreover, although the head member of the toothbrush of the present invention can tilt freely with respect to the hollow member, since the engaging convex portion and the engaging concave portion are engaged, there is little risk that the head member will come off from the hollow member even during, for example, tooth cleaning. Therefore, it is possible to prevent an accident such as the head member getting stuck in the throat, so that the user can use it with confidence.

[0027] (6) Further, either the fitting region or the fitted region has a locked surface provided so as to face the circumferential direction of the central axis, and the other of the fitting region and the fitted region has a locking surface provided so as to face the opposite direction of the locked surface in the circumferential direction. The head member and the hollow member may be configured such that the rotation of each other is restricted by the locking surface locking the locked surface in the circumferential direction.

[0028] That is, since the toothbrush of the present invention has a locking surface and a locked surface, the rotation of the head member about the central axis with respect to the hollow member is restricted. Therefore, although the head member is detachably attached to the hollow member, the head member does not rotate even when the user holds the handle portion and cleans the teeth. Thereby, the user can efficiently clean the teeth by keeping the direction of the bristles in a predetermined direction.

[0029] (7) Further, a male screw portion may be provided on the outside of the tip of the hollow member, and a female screw portion into which the male screw portion can be screwed may be provided inside the opening, and the head member and the hollow member may be configured to be detachably connected.

[0030] That is, since the head member and the hollow member are detachably connected, the toothbrush of the present invention can replace either the head member or the hollow member. Further, the head member can be separated from the intermediate member and then attached to the intermediate member again. Furthermore, since the male screw portion and the female screw portion of the toothbrush of the present invention are screwed together, there is little risk that the head member will come off from the hollow member even during, for example, tooth cleaning.

[0031] (8) Further, the flange portion may be formed in a substantially circular shape when viewed in the central axis direction.

[0032] That is, since the flange portion is substantially circular when viewed in the central axis direction, no linear mountain fold or valley fold is formed in the flange portion. Therefore, the direction in which the structure deforms is less restricted to a specific direction as when a linear mountain fold or valley fold is formed. As a result, the flange portion can be easily deformed in various directions and can be deformed flexibly because it has few corners.

[0033] Therefore, the head member of the toothbrush of the present invention can tilt in a freer direction and can more easily buffer the force applied to the site in the oral cavity.

[0034] (9) Further, the flange portion has a substantially annular surface portion and a substantially annular back surface portion that are arranged to face each other so as to sandwich the interior in the central axis direction, and at least one of the surface portion and the back surface portion has an inclined surface that reduces in diameter as it moves away from the other of the surface portion and the back surface portion, or a convex partial spherical surface that also reduces in diameter.

[0035] In the toothbrush of the present invention, since at least one of the front and back surfaces of the flange portion has an inclined surface or a convex partial spherical surface, the side of the hollow member closer to the head portion of the flange portion tilts, causing the one surface and the other surface to approach and collapse. The inventor has found that at this time, when the force applied to cause the tilt exceeds a certain degree of tilt (deformation amount), it becomes constant. Therefore, even when an accidentally larger force than a certain force is applied to the toothbrush during cleaning in the oral cavity, the toothbrush of the present invention can moderately buffer the force. Thus, depending on the structure of the toothbrush of the present invention, the degree of buffering of the applied force can be easily adjusted by adjusting the configuration such as the thickness, shape, and material of the flange portion during manufacturing.

Advantages of the Invention

[0036] Thus, in the present invention, it is possible to provide a toothbrush having a structure that is lightweight and can buffer the force applied by the bristles to the oral cavity part so as not to damage the user's oral cavity when cleaning the teeth, and moreover, the degree of buffering can be adjusted within a wide range during design and manufacturing. In particular, when a user such as a caregiver or an assistant operates a toothbrush to clean the teeth of an infant or a care recipient, the degree of force applied to the oral cavity of the person is difficult for the user to understand. On the other hand, in the toothbrush of the present invention, since the head member swings freely due to the expansion and contraction of the flange portion, the applied force can be sufficiently absorbed, which is extremely effective in protecting the oral cavity of the person being cleaned.

[0037] And when synthetic resin is used as the material of the hollow member, since it has a hollow structure, the amount of synthetic resin used can be reduced accordingly, and a toothbrush with a low load on the global environment can be provided.

Brief Description of the Drawings

[0038]

Figure 1

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Figure 19

[0039] [First Embodiment] The first embodiment of the present invention will be described with reference to FIGS. 1 to 14. In the front view of FIG. 1(a) and the right side view of FIG. 1(b), 11 is a toothbrush. The toothbrush 11 has a head portion 12 on the tip side and a handle portion 13 that is gripped to guide the head portion 12 into the oral cavity. Bristles 14 are implanted in the head portion 12. In the figure, the direction of arrow U indicates above the toothbrush 11, and the direction of arrow D indicates below. The direction of arrow F indicates forward, and the direction of arrow B indicates backward. Also, the direction of arrow L indicates left, and the direction of arrow R indicates right.

[0040] The central axis of the toothbrush 11 is represented by the center line C1. The cross-section 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 in a substantially circular shape, and the central axis C1 passes through the centers of these cross-sections in the vertical direction. This neck portion 12a refers to the portion of the head portion 12 that is located below the bristle implantation surface 12b where the bristles 14 are implanted. A plurality of bristle implantation holes are formed in the bristle implantation surface 12b, and a plurality of bristles 14 are implanted in the front-rear direction for each bristle implantation hole.

[0041] The handle portion 13 has two bulging portions 15 that bulge in a direction away from the central axis C1, and also has two constricted portions 16 that constrict in a direction approaching the central axis C1. At this time, in order from top to bottom, the upper constricted portion 16a, the upper bulging portion 15a, the lower constricted portion 16b, and the lower bulging portion 15b are arranged. Also, the handle portion 13 has a flange portion 17 that protrudes in a flange shape in a direction away from the central axis C1 above the upper constricted portion 16a.

[0042] FIG. 2 shows a perspective view of the toothbrush 11 in a state where it is disassembled vertically so that the head member 120 and the hollow member 130 are separated. The head member 120 constitutes the head portion 12 in a state combined with the hollow member 130. The hollow member 130 formed in a hollow cylindrical shape constitutes the handle portion 13 in a state combined with the head member 120. At this time, a tip portion 131 described below of the hollow member 130 is located inside the head member 120 and constitutes a part of the head portion 12. 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 in a state where they are combined.

[0043] The head member 120 and the hollow member 130 are formed separately. The head member 120 is a molded product by, for example, injection molding, using various synthetic resins including thermoplastic resins such as polypropylene (PP), saturated polyester (PET), and polyacetal (POM). FIGS. 3(a), (b), and (c) show a front view, a right side partial cross-sectional view, and a bottom view of the head member 120, respectively. An opening 121 that opens downward is provided on the lower bottom side of the head member 120. The opening 121 has a substantially frustum-shaped internal space whose diameter decreases toward the upper side. The inner peripheral portion of the internal space is referred to as an embedded region 122. The lower end of the head member 120 has a circular outer periphery and constitutes an opening edge 123 that is the outlet of the opening 121.

[0044] FIG. 4(a) shows a right side partial cross-sectional view of the head member 120 similar to FIG. 3(b). Further, FIG. 4(b) shows an enlarged view of the lower bottom side of the head member 120 in FIG. 4(a). The embedded region 122 has a substantially annular undercut portion 124 that protrudes radially inward. FIG. 4(c) shows an enlarged view of the undercut portion 124. The undercut portion 124 is provided over the entire inner circumference of the embedded region 122. By providing this undercut portion 124, a engaging concave portion 125 that is recessed radially outward and has a diameter one step larger than the top portion located at the innermost side of the undercut 124 is formed in the portion of the embedded region 122 above the undercut portion 124.

[0045] Further, the inserted region 122 has four locked concave portions 126 that are arranged at uniform intervals in the circumferential direction and are formed to be recessed radially outward. Each locked concave portion 126 forms a substantially trapezoidal space that is wider at the lower side on the inner side. And each locked concave portion 126 has a clockwise locked surface 127a that is an inner wall facing the clockwise CL in a plan view. Also, it has a counterclockwise locked surface 127b that is an inner wall facing the counterclockwise UC in a plan view and opposing each clockwise locked surface 127a in the circumferential direction. Therefore, four clockwise locked surfaces 127a and four counterclockwise locked surfaces 127b are formed on the entire inserted region 122.

[0046] The hollow member 130 is a molded product by blow molding, for example, made of various synthetic resins including thermoplastic resins having elasticity such as low-density polyethylene (LDPE) and polypropylene (PP). FIG. 5(a) shows a plan view of the hollow member 130. FIG. 5(c) also shows a front view. FIG. 5(b) shows a side view of the state where the hollow member 130 is rotated counterclockwise by 30° about the central axis C3 from the posture of FIG. 5(c). FIG. 5(d) shows a cross section and a bottom surface at corresponding positions in the vertical direction. A conical tip portion 131 that tapers upward is provided at the upper end of the hollow member 130. The outer peripheral portion from the tip portion 131 to the uppermost part of the flange portion 17 including the tip portion 131 is called the insertion region 132. The head member 120 and the hollow member 130 are connected and combined by the insertion region 132 being inserted into the inserted region 122. The insertion region 132 is located radially inside the opening 121 and constitutes a part of the head portion 12 in a state where the head member 120 and the hollow member 130 are connected.

[0047] As shown in each cross-sectional view of FIG. 5(d) and the longitudinal sectional view of the hollow member 130 in FIG. 6, the hollow member 130 has a hollow structure in which the entire inside forms a single hollow space E. That is, both the tip portion 131 and the flange portion 17 have a hollow structure, and the hollow space of the entire cylindrical hollow member 130 communicates with the hollow spaces of the tip portion 131 and the flange portion 17 to form a single hollow space E.

[0048] Further, the hollow member 130 is formed so that the wall thickness is uniform throughout. The wall thickness referred to here is represented by the symbol t in FIG. 6.

[0049] As shown in each cross-sectional view of FIG. 5(d), the cross-section of the hollow member 130 is such that the flange portion 17 is formed in a circular shape, the upper constricted portion 16a is formed in a circular shape with a smaller diameter than the flange portion 17, and the upper and lower bulging portions 15a and 15b are formed in a substantially regular hexagon with rounded apex angles. Although not shown, the lower constricted portion 16b is also formed in a substantially regular hexagon with rounded apex angles.

[0050] FIG. 7 shows an enlarged partial view of the vicinity of the tip portion 131 in the right side view of the hollow member 130. The fitting region 132 has a step 133 formed over the entire circumference and downward in the middle in the vertical direction. The neck-like portion below this step 133 is called the neck portion 134. And the tip portion 131 located above the step 133 forms a engaging convex portion 135 whose lower end vicinity portion has a diameter one step larger than that of the neck portion 134 and protrudes radially outward. The diameter of the neck portion 134 is substantially the same as the diameter of the top portion located at the innermost side of the undercut 124.

[0051] Further, the fitting region 132 has four locking convex portions 136 arranged at uniform intervals on the outer circumference of the neck portion 134 and formed to protrude radially outward. Each locking convex portion 136 has a substantially trapezoidal shape that is wider at the lower side, 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. And each locking convex portion 136 has a clockwise locking surface 137a that is an outer wall facing in the clockwise CL direction in plan view. Also, it has a counterclockwise locking surface 137b that is an outer wall facing in the counterclockwise UC direction in plan view and faces each clockwise locking surface 137a in the circumferential direction. Therefore, four clockwise locking surfaces 137a and four counterclockwise locking surfaces 137b are formed in the entire fitting region 132.

[0052] The hollow member 130 has a front surface portion 138 and a back surface portion 139 that constitute the flange portion 17. The upper front surface portion 138 and the lower back surface portion 139 are arranged so as to sandwich the hollow space E inside the flange portion 17 in the vertical direction, each is formed in a substantially annular shape, and the outer peripheral edges of the respective substantially annular shapes are continuously formed in the vertical direction with each other. Among these, the front surface portion 138 has a convex partial spherical surface whose diameter decreases upward. In other words, the front surface portion 138 has a convex partial spherical surface whose diameter decreases as it moves away from the back surface portion 139.

[0053] FIG. 8 shows a state in which the head member 120 and the hollow member 130 are detachably connected. For the head member 120, a partial right side cross-sectional view is shown in the same manner as FIGS. 3(b), 4(a)(b). For the hollow member 130, an outer contour line that can be viewed from the right side is shown in the same manner as FIG. 7. In order to assemble the head member 120 and the hollow member 130, the tip portion 131 is inserted upward into the opening portion 121. At this time, the engaging convex portion 135 is elastically deformed so that the outer diameter becomes smaller than the diameter of the top portion located at the innermost side of the undercut 124 and passes through this top portion. In this way, the fitting region 132 and the fitted region 122 come into contact with each other, and the engaging convex portion 135 and the engaging concave portion 125 are engaged. Further, since the undercut 124 is located below the step 133, the tip portion 131 is locked upward.

[0054] When the tip portion 131 is inserted upward into the opening portion 121 in this way, the angle of the opening portion 121 around the central axis C1 of the tip portion 131 is adjusted so that the corresponding locking convex portions 136 fit into the respective locked concave portions 126. By combining the locking convex portions 136 with the respective locked concave portions 126, in the circumferential direction, each clockwise locking surface 137a faces each clockwise locked surface 127a. Also, each counterclockwise locking surface 137b faces each counterclockwise locked surface 127b. Thereby, the locking surfaces 137a, 137b lock the locked surfaces 127a, 127b in the circumferential direction, and the head member 120 and the hollow member 130 are configured so that their rotations are prevented from each other.

[0055] Conversely, to remove the hollow member 130 from the head member 120, the tip portion 131 is pulled downward from the opening portion 121. Also at this time, the engaging convex portion 135 elastically deforms and the outer diameter becomes smaller than the diameter of the top portion located at the innermost side of the undercut 124, and passes through this top portion. In this way, the fitting region 132 and the fitted region 122 are separated and the engaging convex portion 135 and the engaging concave portion 125 are engaged and disengaged. Thus, the head member 120 and the hollow member 130 are configured to be detachably connected.

[0056] In a state where the head member 120 and the hollow member 130 are connected, as shown in FIGS. 1(a)(b) and 8, the opening edge 123 is vertically adjacent to the flange portion 17 on the surface portion 138 side.

[0057] FIGS. 9(a) to (c) show views of the state in which the head member 120 is gradually inclined with respect to the hollow member 130 as viewed from the plane of the toothbrush 11. FIG. 9(a) represents the state before the head member 120 is inclined. FIGS. 9(b) and (c) represent the state in which the head member 120 is inclined backward when a force is applied backward to the tufted surface 12b as an example. Also, when the force applied to the tufted surface 12b is relaxed, the head member 120 returns to its original posture and restores to the state of FIG. 9(a).

[0058] Also, even when a force is applied to the head portion 12 in a direction other than backward, the head member 120 is inclined in that direction in the same manner as FIGS. 9(b) and (c). Since the toothbrush 11 does not have a structure in which the magnitude of the possible inclination of the head member 120 with respect to the hollow member 130 and the magnitude of the force required to obtain the inclination differ depending on the left-right, front-back directions, the head member 120 can freely incline with respect to the 360° direction of left-right, front-back.

[0059] Figs. 10(a) to (c) show views of the state in which the head member 120 gradually tilts with respect to the hollow member 130, as seen from the right side slightly forward of the toothbrush 11. Fig. 10(a) represents the state before the head member 120 tilts. Figs. 10(b) and (c) represent the state in which the head member 120 tilts when a backward force is applied to the bristle surface 12b as an example. That is, the angle formed by the central axis C2 of the head member 120 and the central axis C3 of the hollow member 130 gradually increases.

[0060] As shown in Figs. 10(b) and (c), as the head member 120 tilts, the hollow member 130 elastically deforms. At this time, mainly, the rear portions of the front surface portion 138 and the rear surface portion 139 of the flange portion 17 are crushed in the vertical direction. On the contrary, the front portions of the front surface portion 138 and the rear surface portion 139 extend in the front-rear direction. And since the engaging convex portion 135 and the engaging concave portion 125 are engaged, the hollow member 130 does not come off from the head member 120. When the applied force is relaxed, the shape of the hollow member 130 formed of an elastic material is restored and the head member 120 returns to its original position and posture.

[0061] Figs. 11(a) to (c) are right side cross-sectional views showing the state in which the head member 120 gradually tilts with respect to the hollow member 130. As shown in the figures, as the head member 120 tilts, the fitting region 132 of the hollow member 130 fitted in the fitting region 122 of the head member 120 also tilts in the same manner. Along with this, the flange portion 17 adjacent to the fitting region 132 tilts. Due to these tilts, the front surface portion 138 and the rear surface portion 139 are crushed so as to approach each other at the rear side by being sandwiched between the fitting region 132 and the upper constricted portion 16a. Also, they extend so as to separate from each other at the front side.

[0062] At this time, when the inclination of the head member 120 is not large, since the shape of the flange portion 17 is not much different from the shape before deformation, the force required for the surface portion 138 and the back surface portion 139 to generate an inclination in an attempt to maintain the original three-dimensional structure increases with the magnitude of the inclination. However, for example, when the inclination of the head member 120 becomes large to a certain extent as in the state of FIG. 11(c), since the surface portion 139 and the back surface portion 139 are in a substantially contacting state, it changes from the original three-dimensional structure to a state close to a two-dimensional structure. The inventor has found that the force required to cause a further inclination at this stage suffices to be constant regardless of the magnitude of the inclination.

[0063] With the above configuration, the toothbrush 11 includes the hollow member 130 that constitutes the handle portion 13, and thus is lightweight because a material such as synthetic resin is not filled in the hollow space E of the hollow member 130. Therefore, even a user with a weak grip strength, such as an elderly person or an infant, can easily clean the teeth by operating the toothbrush 11.

[0064] Further, since the hollow member 130 is formed of an elastic material, the handle portion 13 gripped by the user has elasticity and can buffer the force applied to the site in the oral cavity through the head portion 12 when cleaning the teeth. Moreover, since the hollow member 130 elastically deforms, the handle portion 12 returns to its original shape by itself even after absorbing and deforming the force. Therefore, the user can continue to clean the teeth thereafter.

[0065] Furthermore, since the interior of the cylindrical portion of the hollow member 130 communicates with the interior of the flange portion 17, the free deformation of the flange portion 17 is less likely to be hindered due to these simple internal structures. For example, when a shearing force is applied to the toothbrush 11 to bend the upper portion of the hollow member 130 such as the tip portion 131 and the neck portion 134 with respect to the central axis C1 of the toothbrush 11, the flange portion 17 allows the inner portion attempting to bend to be compressed and the outer portion attempting to bend to extend. As a result, when the shearing force is applied, the upper portion of the hollow member 130 can tilt in any direction with respect to the lower portion of the flange portion 17. Then, the head member 120 can freely swing with respect to the hollow member 130.

[0066] When the head member 120 tilts in a free direction, the user can evenly apply the bristles to each part in the oral cavity for cleaning. For example, when the head member 120 can only tilt in a fixed direction, only a part of the bristles 14 may hit. In contrast, the toothbrush 11 can apply the entire bristles 14 in a free direction, angle, etc., so the cleaning effect is high. Also, even if infants, the elderly, etc. fall while holding the head part, since the head member 120 tilts in a free direction, the toothbrush 11 can buffer the impact from all directions during the fall, and there is little risk of the head part 12 hitting the user's throat and causing injury.

[0067] Due to such a structure, by adjusting the configuration such as the thickness, shape, and material of the flange portion 17 during manufacturing, the degree to which the head member 120 can freely tilt with respect to the hollow member 130, that is, the firmness of the entire toothbrush 11 can be easily adjusted. In this way, the toothbrush 11 can buffer the force applied by the bristles 14 to the parts in the oral cavity so as not to damage the user's oral cavity when cleaning the teeth, and moreover, the degree of buffering can be easily adjusted during manufacturing.

[0068] In addition, since the hollow member 130 has an internal structure in which the inside of the cylindrical portion and the inside of the flange portion 17 communicate with each other, when the material is a synthetic resin, the whole can be integrally molded, and it can be manufactured simply and efficiently by adopting a manufacturing method such as blow molding.

[0069] Next, when the user presses a part in the oral cavity with the bristles 14 to clean the teeth, the head member 120 transmits the reaction force received from this part to the hollow member 130 connected to the head member 120. And when a shearing force that bends the hollow member 130 is generated by the reaction force, this shearing force is transmitted from the opening of the head member 120 to the hollow member 130. At this time, since the opening edge 123 and the flange portion 17 of the toothbrush 11 are adjacent to each other, the shearing force is efficiently transmitted to the flange portion 17. By the way, the hollow member 130 elastically deforms so that the inner part where the flange portion 17 tends to bend is crushed and the outer part where it tends to bend extends, thereby buffering the shearing force. And since the shearing force is efficiently transmitted to the flange portion 17, the hollow member 130 can easily adjust the degree of buffering the shearing force by adjusting the configuration such as the thickness, shape, and material of the flange portion 17. In this way, the toothbrush 11 can buffer the force applied by the bristles 14 to the part in the oral cavity so as not to damage the user's oral cavity when cleaning the teeth, and moreover, it can be manufactured by easily adjusting the degree of buffering.

[0070] Next, since the toothbrush 11 has the bulge 15 in addition to the handle portion 13 being elastically deformable, the user can easily support the toothbrush 11 even with a weak grip force of the elderly, infants, etc. by gripping the thick bulge 15 with a finger or fingers and the palm. Moreover, since the handle portion 13 is constituted by the hollow member 130 having a hollow structure, it is soft, and even a user with a weak grip force can firmly grip the hollow bulge 15. Therefore, there is little risk that the toothbrush 11 will fall out of the hand during tooth cleaning.

[0071] In addition, since the toothbrush 11 has a constricted portion 16, when the user places a finger on the constricted portion 16, the posture of the toothbrush 11 can be stabilized and supported when cleaning the teeth. In particular, since the upper constricted portion 16a is provided between the flange portion 17 and the upper bulging portion 15a, the user can, for example, place the index finger on the upper constricted portion 16a and place the middle finger, ring finger, etc. on the respective bulging portions 15a, 15b, so that while the index finger controls the position, angle, etc. of the head portion 12, the middle finger, ring finger, etc. can securely grip the handle portion 13. In this way, efficient tooth cleaning can be performed with the toothbrush 11.

[0072] Next, since the head member 120 and the hollow member 130 are detachably connected, the toothbrush 11 can replace either the head member 120 or the hollow member 130. Therefore, for example, only one of the head member 120 and the hollow member 130 can be discarded and the remaining can be continuously used without waste, and the load on the global environment is small.

[0073] Also, the head member 120 can be separated from the hollow member 130 and then attached to the hollow member 130 again. Therefore, the user can remove the head member 120 to expose the fitting region 132 and the fitted region 122 for cleaning. As a result, the toothbrush 11 can always be kept clean.

[0074] Furthermore, since the engaging convex portion 135 and the engaging concave portion 125 of the toothbrush 11 engage with each other, for example, even during tooth cleaning, the risk of the head member 120 coming off from the hollow member 130 is small. Therefore, an accident such as the head member 120 getting stuck in the throat can be prevented, so the user can use it with confidence.

[0075] Moreover, since the toothbrush 11 has locking surfaces 137a, 137b and locked surfaces 127a, 127b, rotation of the head member 120 about the central axis C2 with respect to the hollow member 130 is restricted. 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 holds the handle portion 13 and cleans the teeth. As a result, the user can efficiently clean the teeth by keeping the direction of the bristles 14 in a predetermined direction.

[0076] Finally, since the flange portion 17 is substantially circular when viewed in the direction of the central axis C3, linear mountain folds or valley folds such as a square or a polygon are not formed in the flange portion 17. Therefore, the direction of deformation when a force is applied is less restricted to a specific direction as when a linear mountain fold or valley fold is formed. As a result, the flange portion 17 is easily deformed in various directions and can be deformed flexibly because it has few corners.

[0077] Therefore, the head member 120 of the toothbrush 11 can tilt in a freer direction and can more easily buffer the force applied to the site in the oral cavity.

[0078] And, since the surface portion 138 of the flange portion 17 of the toothbrush 11 has a convex partial spherical surface, the portion of the hollow member 130 above the flange portion 17 tilts so that the surface portion 138 and the back surface portion 139 come closer and are crushed. The inventor has found at this time that when the force applied to cause the tilt exceeds a certain amount of tilt (deformation amount), the force becomes constant. Therefore, even when an accidentally larger force than a certain force is applied to the toothbrush 11 during cleaning in the oral cavity, the toothbrush 11 can moderately buffer the force. Thus, with the structure of the toothbrush 11 of the present invention, the degree of buffering of the applied force can be easily adjusted by adjusting the configuration such as the thickness, shape, and material of the flange portion 17 during manufacturing.

[0079] [Embodiment] The inventor measured the bending strength of the toothbrush 11 of the present invention. FIGS. 12(a) and (b) show photographs of the apparatus used for the measurement. The inventor prepared a toothbrush 11 without bristles 14 implanted, and held the toothbrush 11 cantilevered by clamping the hollow member 130 with a clamp C in the vertical direction of the photograph so that the central axis C1 direction thereof coincides with the horizontal direction and the bristle implantation surface 12b faces upward. Then, using a bending strength measuring instrument having a pressure element I at its tip, while applying the pressure element I to the bristle implantation surface 12b, the pressure element I was lowered at a speed of 100 mm per minute to measure the load applied to the pressure element I. The distance by which the pressure element I descends was set to a maximum of 25 mm. Also, the unit for measuring the load was Newton (N). The photograph in FIG. 12(a) shows the state before the pressure element I is lowered, and the photograph in FIG. 12(b) shows the state where the pressure element I has been lowered by 25 mm.

[0080] The toothbrush 11 of the present invention used in this example has an overall length L in the vertical direction shown in FIG. 13 of 183.5 mm. In contrast, the inventor set the protruding length L1, which is the distance between the upper end of the toothbrush 11 and one end of the clamp C closer to the upper end of the toothbrush 11, to 80.0 mm. The toothbrush 11 has a head portion length L2 from the upper end to the opening edge 123, which is the length of the head portion 12, of 71.8 mm. As a result, the handle portion protruding length L3, which is the protruding length of the handle portion 13, was 8.2 mm.

[0081] Also, for the toothbrush 11 of this example, polypropylene (PP) was adopted as the material for both the head member 120 and the hollow member 130. The hollow structure of the hollow member 130 is formed by a uniform wall thickness t as shown in FIG. 6 and has a thickness of 0.4 mm.

[0082] On the other hand, the inventor prepared a toothbrush without a hollow structure as Comparative Example 1 for comparison with this example. The toothbrush of Comparative Example 1 was also measured by holding it with a clamp C so that the protruding length L1 was 80.0 mm, similar to the toothbrush 11 of this example. Polypropylene (PP) was adopted as the material of the toothbrush of Comparative Example 1.

[0083] By lowering the plunger I, the head member 120 of the toothbrush 11 tilted backward with respect to the hollow member 130. As the head member 120 tilted, the upper end of the toothbrush 11 moved backward. The backward movement distance of this upper end was called the deformation distance d (distance), and the deformation distance d of the toothbrush 11 of this embodiment during lowering was measured. Also, for Comparative Example 1, the deformation distance d was measured in the same manner as in this embodiment.

[0084] Graph A in FIG. 14 represents the load (N) applied to the plunger I at each deformation distance d when the plunger I was 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 units, and the vertical axis represents the load (N). Also, Graph B represents the load (N) applied to the plunger I at each deformation distance d of Comparative Example 1.

[0085] As shown by Graph B, in the toothbrush of Comparative Example 1, the load applied to the plunger I increased almost proportionally as the deformation distance d increased. On the other hand, as shown by Graph A, in the toothbrush 11 of this embodiment, the load increased proportionally to the deformation distance d immediately after the deformation started, but after that, the load did not increase even as the deformation distance d increased and remained horizontal. Also, the magnitude of the load itself of the toothbrush 11 of this embodiment was smaller than that of the toothbrush of Comparative Example 1.

[0086] From these, the inventor found that the toothbrush 11 has a small load applied to the plunger I with respect to an external force, and thus the degree to which it can buffer the force is larger than that of the toothbrush of Comparative Example 1. Also, it was found that when the load applied to the toothbrush 11 increased to a certain extent, after exceeding a certain deformation distance d, that is, a certain inclination, it showed a horizontal value without further increase. In this way, it was found that when exceeding a certain inclination (deformation amount), the force applied to cause that inclination becomes constant.

[0087] [Second Embodiment] The second embodiment of the present invention will be described with reference to FIG. 15. In the front view of FIG. 15, 21 is a toothbrush, which has a head portion 22 on the tip side and a handle portion 23 that is gripped to guide the head portion 22 into the oral cavity. Bristles 24 are implanted in the head portion 22. The handle portion 23 has two bulging portions 25 protruding upward and downward in a direction away from the central axis C1 of the toothbrush 21, and also has two constricted portions 26 constricting in a direction approaching the central axis C1. At this time, in order from top to bottom, an upper constricted portion 26a, an upper bulging portion 25a, a lower constricted portion 26b, and a lower bulging portion 25b are arranged. Further, the handle portion 23 has a flange portion 27 protruding in a flange shape in a direction away from the central axis C1 above the upper constricted portion 26a.

[0088] The head portion 22 and the handle portion 23 are composed of a head member 220 and a hollow member 230 formed separately. The head member 220 constitutes the head portion 22 in a state combined with the hollow member 230. The hollow member 230 formed in a hollow cylindrical shape constitutes the handle portion 23 in a state 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.

[0089] The hollow member 230 has a front surface portion 238 and a back surface portion 239 that constitute the flange portion 27. The upper front surface portion 238 and the lower back surface portion 239 are arranged so as to sandwich the intermediate space E inside the flange portion 27 in the vertical direction, each is formed in a substantially annular shape, and the outer peripheral edges of the respective substantially annular shapes are continuously formed in the vertical direction with each other. Among these, the front surface portion 238 has an inclined surface that tapers upward. In other words, the front surface portion 238 has an inclined surface that tapers as it moves away from the back surface portion 239.

[0090] Other configurations are common to the first embodiment.

[0091] As described above, since the surface portion 238 of the flange portion 27 of the toothbrush 21 has an inclined surface, similar to the case of the surface portion 138 having a convex partial spherical surface in the first embodiment, the upper portion of the hollow member 230 above the flange portion 27 is inclined, causing the surface portion 238 and the back surface portion 239 to approach each other and collapse. At this time, the inventor found that when the force applied to cause the inclination exceeds a certain degree of inclination (deformation amount), the force becomes constant. Therefore, even when an accidentally greater force than a certain force is applied to the toothbrush 21 during cleaning in the oral cavity, the toothbrush 21 can appropriately buffer the force. Thus, with the structure of the toothbrush 21 of the present invention, by adjusting the configuration such as the thickness, shape, and material of the flange portion 27 during manufacturing, the degree of buffering of the applied force can be easily adjusted.

[0092] [Third Embodiment] The third embodiment of the present invention will be described with reference to FIG. 16. In the partial front view of FIG. 16, 31 is a toothbrush, which has a head portion 32 on the tip side and a handle portion 33 that is gripped to guide the head portion 32 into the oral cavity. Bristles 34 (not shown) are implanted in the head portion 32. The handle portion 33 has two bulging portions 35 bulging in a direction away from the central axis C1 of the toothbrush 31, and also has two constricted portions 36 constricting in a direction approaching the central axis C1. Among these, only the upper constricted portion 36a is shown. Further, the handle portion 33 has two-stage flange portions 37 protruding in a flange shape in a direction away from the central axis C1 above the upper constricted portion 36a. The upper flange portion 37a and the lower flange portion 37b are arranged in order from top to bottom.

[0093] The hollow member 330 has a hollow structure in which the entire interior forms a single hollow space E. That is, the upper and lower flange portions 37a, 37b each have a hollow structure, and the hollow space of the entire cylindrical hollow member 330 communicates with each flange portion 37a, 37b to form a single hollow space E.

[0094] The hollow member 330 has a upper surface portion 338a, an upper back surface portion 339a, a lower surface portion 338b, and a lower back surface portion 338b that respectively constitute each flange portion 37a, 37b. In each of the upper and lower stages, the upper surface portions 338a, 338b and the lower back surface portions 339a, 339b are arranged so as to sandwich the hollow space E inside each flange portion 37a, 37b in the vertical direction, each is formed in a substantially annular shape, and the outer peripheral edges of the respective substantially annular shapes are continuously formed in the vertical direction with each other. Each of these surface portions 338a, 338b has an inclined surface whose diameter decreases upward. In other words, the upper surface portion 338a of the upper stage has an inclined surface whose diameter decreases as it moves away from the upper back surface portion 339a. Also, the lower surface portion 338b of the lower stage has an inclined surface whose diameter decreases as it moves away from the lower back surface portion 339b.

[0095] Furthermore, among these, the upper back surface portion 339a of the upper stage has an inclined surface whose diameter decreases downward. In other words, the upper back surface portion 339a of the upper stage has an inclined surface whose diameter decreases as it moves away from the upper surface portion 338a.

[0096] Other configurations are common to the second embodiment.

[0097] As described above, since the toothbrush 31 has the two-stage flange portions 37a, 37b, compared with the case of having only a single-stage flange portion, by adjusting the configurations such as the thickness, shape, and material of each flange portion 37a, 37b during manufacturing, it is possible to adjust the degree of buffering of the applied force in a wider range. Also, in FIG. 16, an embodiment is shown in which the outer diameter of the upper flange portion 37a and the outer diameter of the lower flange portion 37b are substantially the same. However, in addition to this, by making the upper and lower dimensions different, it is also possible to adjust the degree of buffering of the applied force in a wider range.

[0098] [Fourth Embodiment] A fourth embodiment of the present invention will be described with reference to FIG. 17. In the front view of FIG. 17(a) and the right side view of FIG. 17(b), 41 is a toothbrush. The toothbrush 41 has a head portion 42 on the tip side and a handle portion 43 that is gripped to guide the head portion 42 into the oral cavity. Bristles 44 are implanted in the head portion 42.

[0099] The toothbrush 41 is combined with an upper head member 420 and a lower hollow member 430. The head member 420 constitutes the head portion 42 in a state combined with the hollow member 430. The hollow member 430 formed in a hollow cylindrical shape constitutes the handle portion 43 in a state combined with the head member 420. At this time, the tip portion 431 of the hollow member 430 is located inside the head member 420 and constitutes a part of the head portion 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 in a state where they are combined.

[0100] The head member 420 and the hollow member 430 are formed separately. FIG. 18 shows a partial plan cross-sectional view of the head member 420 and a partial plan view of the hollow member 430 at a position where the head member 420 and the hollow member 430 are combined. An opening 421 that opens downward is provided on the lower bottom 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 the combined internal space is called an embedded region 422. The lower end of the head member 420 has a circular outer periphery and constitutes an opening edge 423 that is the outlet of the opening 421.

[0101] The embedded region 422 has a female screw portion 425 in the inner peripheral portion of the upper internal space. The head member 420 has a screw groove 425a that is recessed radially outward in the female screw portion 425. The screw groove 425a draws a helix around the central axis C2 of the head member 420.

[0102] The hollow member 430 has a male screw portion 435 on the outer periphery of its tip portion 431. In the male screw portion 435, the hollow member 430 has a thread 435a protruding radially outward. The thread 435a describes a helix around the central axis C3 of the hollow member 430. The outer peripheral portion from the tip portion 431 to the uppermost part of the flange portion 47 including the tip portion 431 is called the fitting region 432. The head member 420 and the hollow member 430 are combined by screwing the female screw portion 425 and the male screw portion 435 together and fitting the fitting region 432 into the fitted region 422.

[0103] Other configurations are common to the first embodiment or the second embodiment.

[0104] With the above configuration, since the head member 420 and the hollow member 430 are detachably connected, the toothbrush 41 can replace either the head member 420 or the hollow member 430. Also, the head member 420 can be separated from the intermediate member 430 and then attached to the intermediate member 430 again. Further, since the male screw portion 435 and the female screw portion 425 of the toothbrush 41 are screwed together, there is little risk that the head member 420 will come off from the hollow member 430 even during, for example, tooth cleaning.

[0105] As described above, the embodiments of the present invention have been illustrated, but the present invention is not limited to these embodiments, and various modifications are possible without departing from the spirit of the present invention.

[0106] For example, the material of the head member is not limited to polypropylene (PP), saturated polyester (PET), polyacetal (POM), etc., and any material that can implant bristles and has strength to withstand toothbrushing may be other synthetic resins or materials other than synthetic resins. Also, it may be formed by a manufacturing method other than injection molding.

[0107] In addition, the material of the hollow member is not limited to low-density polyethylene (LDPE), polypropylene (PP), etc., and any material that can be formed into a hollow shape, has elasticity, and has sufficient strength to support the head member may be used, such as other synthetic resins or materials other than synthetic resins. Further, it may be formed by a manufacturing method other than blow molding.

[0108] The cross-section or lower end of the head member may be formed into a shape other than circular, and the cross-section of the hollow member may be formed into a shape other than circular or substantially regular hexagonal. The head member may have a polygonal cross-section, for example, as long as it can accommodate the joining structure with the hollow member. Also, the cross-section of the hollow member may be a polygon other than a hexagon, a polygon other than a regular polygon, etc., as long as it can be easily grasped by fingers and palm.

[0109] The wall thickness of the hollow member does not have to be uniform throughout. Even if it is non-uniform, as long as the handle part has elasticity, the head part can tilt freely, and the toothbrush has the necessary strength, it is acceptable.

[0110] The engaging concave part and the engaging convex part do not have to be a recess and a protruding part with a diameter one step larger as exemplified in the first embodiment. As long as the head member and the hollow member can be securely and detachably connected, for example, the engaging concave part may be groove-shaped and the engaging convex part may be ring-shaped that can fit into the groove.

[0111] Even if the engaging concave part is provided on the head member and the engaging convex part is not provided on the hollow member, as long as the head member and the hollow member are configured to be detachably and securely connected, instead, the engaging concave part may be provided on the hollow member and the engaging convex part may be provided on the head member.

[0112] Regarding the locked recess portion, the locking projection, the locked surface, and the locking surface, the recess provided in the head member is referred to as the locked recess portion and the locked surface, and the projection provided in the hollow member is referred to as the locking projection and the locking surface. However, these are names for convenience of distinction. For example, the recess may be referred to as the locking recess portion and the locking surface, and the projection may be referred to as the locked projection and the locked surface. Further, if the relative rotation between the head member and the rotating member can be prevented, for example, a projection may be provided on the head member side and a recess may be provided on the hollow member side.

[0113] The arrangement of the partial spherical surface or the inclined surface in the flange portion is not limited to the examples in the first to fourth embodiments. As long as the head member can freely swing with respect to the hollow member, for example, the back surface portion may have a convex partial spherical surface whose diameter decreases downward, or may have an inclined surface whose diameter decreases downward. Further, both the front surface portion and the back surface portion may have these partial spherical surfaces or inclined surfaces, and moreover, either one of the front surface portion and the back surface portion may have a partial spherical surface and the other may have an inclined surface.

[0114] The shape of the flange portion in plan view is not necessarily limited to a circle. As long as the hindrance to the inclination of the head member with respect to the hollow member is small, for example, it may be an ellipse, an oblong, a polygon with rounded vertices, or the like.

[0115] The flange portion is not necessarily limited to a single-stage or upper and lower two-stage configuration. As long as it can absorb the force applied to the site in the oral cavity and deform and then restore itself to the original shape, for example, it may be an upper and lower three-stage or four-stage or more configuration.

[0116] The head portion is not necessarily limited to a shape that gradually becomes thinner toward the upper side or a shape that gradually becomes thinner from the middle in the vertical direction as in the fourth embodiment. As long as the weight balance in cleaning the teeth is not deteriorated, for example, it may be a two-stage shape in which the diameter becomes smaller from the middle as shown in the partial plan view of FIG. 19.

[0117] The following matters are disclosed. (Claim 1) A head member constituting a head portion where bristles are implanted on the tip side, and a hollow member that is connected to the head member, forms a handle portion that is gripped to guide the head portion into the oral cavity, is in a hollow cylindrical shape, and is formed of an elastic material. The hollow member has a flange-shaped portion that protrudes in a flange shape in a direction away from its central axis. The flange-shaped portion is formed hollow, and its interior communicates with the interior of the hollow cylindrical portion. At their connecting portions, one of the head member and the hollow member has a locked surface provided so as to face in the circumferential direction of the central axis, and the other has a locking surface provided so as to face in the opposite direction to the locked surface in the circumferential direction. A toothbrush characterized by the above. (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-shaped portion of the hollow member are adjacent to each other in the central axis direction. The toothbrush according to claim 1, characterized by the above. (Claim 3) The handle portion has a bulging portion that bulges in a direction away from the central axis at a portion other than the flange-shaped portion. The toothbrush according to claim 1, characterized by the above. (Claim 4) The handle portion has a constricted portion that constricts in a direction approaching the central axis between the flange-shaped portion and the bulging portion. The toothbrush according to claim 3, characterized by the above. (Claim 5) The head member has an opening on the proximal end side. The tip of the hollow member, which is the tip of the hollow member, is fitted into the opening. Either one of the fitting region of the tip of the hollow member and the fitted region of the opening, which are both the connecting portions, has an engaging 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 concave portion that is recessed in the away direction. The engaging convex portion and the engaging concave portion are engaged with each other, the head member and the hollow member are configured to be detachably connected to each other The toothbrush according to any one of claims 1 to 4, characterized in that. (Claim 6) One of the fitting region and the fitted region has the engaged surface, and the other of the fitting region and the fitted region has the engaging surface, By the engaging surface locking the engaged surface in the circumferential direction, the rotation of the head member and the hollow member is configured to be stopped from each other The toothbrush according to claim 5, characterized in that. (Claim 7) The flange portion is formed in a substantially circular shape when viewed in the central axis direction The toothbrush according to any one of claims 1 to 6, characterized in that.

Industrial Applicability

[0118] The present invention can be used for a toothbrush for cleaning a user's teeth with implanted bristles.

Explanation of Signs

[0119] 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 Constricted portion 17, 27, 37, 47 Flange portion 120, 220, 320, 420 Head member 121, 421 Opening 122, 422 Fitted region 123, 423 Opening edge 124 Undercut portion 125 Engaging concave portion 126 Engaged concave portion Hollow members 130, 230, 330, 430 Tip portions 131, 431 Insertion regions 132, 432 Step 133 Engaging convex portion 135 Locking convex portion 136 Surface portions 138, 238, 338 Back surface portions 139, 239, 339 Female screw portion 425 Male screw portion 435

Claims

1. A head member constituting a head part in which brush bristles are attached at a tip side; a hollow member that is connected to the head member, constitutes a handle portion that is gripped to guide the head portion 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 portion is formed hollow, and the inside of the flange portion communicates with the inside of the hollow cylindrical portion, At a connecting portion between the head member and the hollow member, one of the head member and the hollow member has a locking surface provided so as to face in a circumferential direction of the central axis, and the other of the head member and the hollow member has a locking surface provided so as to face in the opposite direction to the locking surface in the circumferential direction. A toothbrush characterized by

2. The head member has an opening on a 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.

3. The handle portion has a bulging portion that bulges away from the central axis in a portion other than the flange portion.

2. The toothbrush of claim 1.

4. The handle portion has a narrowed portion between the flange portion and the bulge portion, the narrowed portion being narrowed toward the central axis.

4. The toothbrush of claim 3.

5. The head member has an opening on a proximal end side, A 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 protruding in a direction away from the central axis, The other of the insertion region and the inserted region has an engagement recess that is 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 disposed on the surface of the tooth.

6. The engaging surface is provided on one of the insertion region and the received region, and the engaging surface is provided on the other of the insertion region and the received region; 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.

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 disposed on the surface of the tooth.

Images