EP0389711A2

EP0389711A2 - Toothbrush

Info

Publication number: EP0389711A2
Application number: EP89310349A
Authority: EP
Inventors: Hideyasu Matoba
Original assignee: Meito Co Ltd
Current assignee: Meito Co Ltd
Priority date: 1989-03-28
Filing date: 1989-10-10
Publication date: 1990-10-03
Also published as: JPH02252406A; CA2009763A1; KR900013902A; EP0389711A3; BR9001407A; AU4982490A

Abstract

A folding toothbrush capable of shaping the hair edge of the brush automatically. The toothbrush includes a front handle (4) with a hair-planted part (2) and a rear handle (3) with a case part (5). Both handles (3, 4) are rotatably connected by pivots and connection holes (6, 7). When the handles (3, 4) are extended, they are aligned in a straight line. When the handles (3, 4) are folded, the hair-planted part (2) of the front handle (4) is received in the case part (5) of the rear handle (3). The case part (5) includes slanting case side (22), front (24) and rear walls (25). The hair edge is inwardly bent by the slanting case walls in the folded state. The hair edge is naturally shaped by the case walls.

Description

This invention relates to a toothbrush having means for reforming the hair edge.
By repetition of usage, the hair edge of a toothbrush is gradually bending outward.
Some parts of hair edge is likely to bend toward side directions. Another parts of hair edge is likely to bend toward forward or rear directions.
If one cleans his teeth with a toothbrush whose hair edge has bent outward, the outward bending hair edge rubs his gums. Sometimes the gums are hurt and blood oozes.
Therefore toothbrushes with outward bending hair edge tend to be abandoned.
The inventor has been trying to make an improved toothbrush having hair edge which would be unlikely to band outward. If the hair was fabricated from the material with higher rigidity, the hair edge would resist the force which acts to bend the hair edge outward. However heightening the rigidity of hair is not an appropriate remedy for prohibiting hair edge from bending outward, because the material of hair of toothbrush is definitely determined. It is hopeless to prevent hair edge of toothbrush from bending outward by changing the material of hair.
The Inventor thinks that reforming hair edge inward is the best way to prevent hair edge from bending outward.
A convenient way of reforming hair edge may be to enclose the hair-planted part by some case and push the hair edge inward by the side walls of case.
However such toothbrushes have never been manufactured.
Japanese Utility Model Laying Open No. 62-24726 ( laid open on Feb. 14,1987 ) has disclosed a folding toothbrush having a case for enclosing the hair-planted part. In the folded state the case encloses the hair planted part. But the hair edge separates from the wall of case. Thus this toothbrush could enjoy no effect for reforming hair edge despite having a case. The case only protects the hair-planted part from being soiled.
Japanese Utility Model Laying Open No.62-42435 ( laid open on March 13,1987 ) has disclosed a toothbrush having a case for enclosing only the hair planted part. The brush case has two side walls which can open sideward. When one cleans his teeth with the toothbrush, he opens the side walls of the case and extracts the toothbrush out of the case. When he finishes cleaning, he places the hair-planted part into the case and shuts the case. The role of the case is only to protect the hair-planted part from being soiled. The case has not the role of reforming the hair edge.
One purpose of the invention is to provide a toothbrush in which hair edge is prevented from bending outward.
Another purpose of the invention is to provide a toothbrush convenient for carrying with.
To achieve the foregoing purposes the toothbrush of this invention comprises a front stick with both ends having plvots on one end, a hair-planted part planted on another end of the front stick, an upward opened rear stick with both ends having connection holes on one end for connecting the pivots therein, and a case part shaped on another end of the rear stick, the case part having slanting case side walls, a case bottom wall, a case rear wall and a slanting case front wall, wherein the front stick is rotatably connected to the rear stick by the pivots and the connection holes, the front stick and rear stick can be folded or extended by rotating the sticks around the pivots and connection holes , in the extended state the front stick and the rear stick are aligned along a straight line, in the folded state the hair-planted part of the front stick is enclosed by the case part of the rear stick, characterized in that in the folded state, the hair edge of the hair-planted part is inward reformed at least by the slanting case side walls and the slanting case front wall.
Preferably the rear stick includes an elastic piece formed on the end near the connection holes, the elastic piece includes a claw, the front stick includes a projection on the end near the pivots and in the extended state the claw of the rear stick grips the projection of the front stick.
The upward opened rear stick preferably has side walls and a bottom wall, middle part of the front stick has step sides and the middle part of the front stick is partially held between the side walls of the rear stick in the folded state.
It is also preferred that the case rear wall is also slanting for reforming the rear hair edge inward.
The invention will be more fully understood from the following description given by way of example only with reference to the several figures of the accompanying drawings in which

FIG. 1 is a partially sectioned front view of a unified asymmetric planetary gear assembly as an embodiment of the invention
FIG.2 is a front view of the toothbrush in an extended state.
FIG.3 is a bottom view of the toothbrush in an extended state.
FIG.4 is a vertically-sectioned front view of the toothbrush in an extended state.
FIG.5 is a front view of the toothbrush in a folded state.
FIG.6 is a front view of the toothbrush in an intermediate state.
FIG.7 is an enlarged vertically sectioned front view of the toothbrush in a folded state.
FIG.8 is an enlarged view of the case part sectioned in a plane vertical to the longitudinal direction in a folded state.

The toothbrush of this invention is a folding toothbrush. A brushstick (1) consists of a front stick (4) having a hair-planted part (2) and a rear stick (3) having a case part (5).
The rear end of the front stick (4) is rotatably connected with the front end of the rear stick (3).
The means for connecting both sticks is now explained. The front stick (4) has pivots (6) formed on both sides at the rear end. The rear stick (3) is an elongate box-shaped stick opened upward. The rear stick (3) has connection holes (7) perforated at the front ends of side walls.
The pivots (6) on the rear ends of the front stick (4) have been inserted into the connection holes (7) of the rear stick (3).
The front stick (4) can rotate in relation to the rear stick (3) around the pivot (6) and the connection holes (7).
The brushstick (1) can be extended along a straight line by aligning the front stick (4) with the rear stick (3) as shown in FIG.1 to FIG.3. This state is called extended state.
Otherwise the brushstick (1) can be folded by putting the front stick (4) in the rear stick (3) as shown in FIG.5 and FIG.7. This state is called folded state.
One cleans his teeth by the toothbrush in an extended state. To stabilize the extended state, a notch (10) is vertically cut at the rear end of the front stick (4) and a projection (11) with a slanting wall is formed, following the notch (10).
Two longitudinal slits (13) are cut at the front end ( rear the connection holes (7) ) of the rear stick (3). The middle portion sectioned between two slits (13) becomes an elastic piece (8) cantilevered by a bottom wall (20) of the rear stick (3).
A claw (9) is shaped at the free end of the inner surface of the elastic piece (8).
In the extended state the claw (9) of the rear stick (3) grips the projection (11) of the front stick (3). By the grip of the claw (9) to the projection (11) the front stick (4) and the rear stick (3) align along a straight line. The claw (9) and the projection (11) stabilize the extended state of the brushsticks.
The rear end of the rear stick (3) is a case part (5) which is slightly lower than other part of the rear stick (3). A plurality of ventilating holes (12) are perforated on a bottom wall (23) of the case part (5). The ventilating holes (12) allow air to ventilate in the case part (5) for drying wet hair-planted part (2).
Preferably the rear stick (3) and the front stick (4) are made from plastics e.g. polyacetal, polypropylene, polyvinylchloride, polyethylene, polystyrene and so on. Both sticks (3) and (4) can be made from same material.
But it is more preferable to make the rear stick with more elastic material than the material of the front stick for heightening the elasticity of the elastic piece (8) of the rear stick (3).
The rear stick (3) has a room for receiving most portion of the front stick (4). Thus the rear stick (3) is an elongate, upward-opened, box-shaped stick. Upper verges of the opened rear stick (3) consist of straight verges (15), curved verges (16) and straight case verges (17) in turn from the end near the pivots (6). The straight case verges (17) are lower than the straight verges (15) near the pivots (6). The curved verges (16) smoothly connect the straight verges (15) with the straight case verges (17).
Both sticks (3) and (4) can be tinted in same color. But it is more preferable to tint the front stick (4) and the rear stick (3) in different colors. For example, the front stick (4) is white, and the rear stick (3) is tinted in some colors other than white, e.g. in green, blue or red. The bright contrast of colors heightens the aesthetic value of the toothbrush.
The rear stick (3) includes right and left side walls (21) vertical to the direction of pivots (6) and a bottom wall (20) in parallel with the pivots (6). Owing to the side walls (21) and the bottom wall (20), vertically-sectioned view of the rear stick (3) looks like "U". The U-shaped rear stick (3) can receive most part of the front stick (4).
The gap between side walls (21) is narrower in the middle but wider near the front and rear ends.
The rear ends of the side walls (21) are smoothly continue to the case side walls (22).
The bottom wall (20) is a flat plane which is succeeded by a case bottom wall (23) via a case rear wall (24). The case bottom wall (23) is lower than the bottom wall (20) of the rear stick (3).
The case side walls (22) include slanting planes which bend inward near the bottom.
Similarly the case front wall (25) and the case rear wall (24) include slanting planes which bend inward near the bottom. The slanting planes of the case walls (22), (24) and (25) are important for this invention, because the slanting planes play essential role for reforming hair edge.
The front stick (4) includes a cavity (14) on the upper surface near the pivots (6). The existence of cavity (14) spares plastic material and lightens the toothbrush. The cavity (14) is dispensable.
The front stick (4) includes a hair-planted part (2) on its front end i.e. the end far away from the pivots (6). The hair-planted part (2) has a wide surface. But the middle part following the hair-planted part (2) of the front stick (4) is narrow in width. Behind the hair-planted part (2), step sides (18) are formed at a level lower than half of thickness of the stick (4). The step sides (18) are horizontal from the rear end to the middle of the stick. But the step side (18) is upward succeeded by curved step (19) in the vicinity of the hair-planted part (2).
The bottom surface (28) of the front stick (4) is slightly tapered in the neighborhood of the pivots (6). Namely the thickness of the stick (4) is biggest at the end neighboring the notch (10) and decreases with the distance from the notch (10).
The tapered bottom surface (28) is ended at a vertical terminal surface (26) just before the notch (10).
The operation for closing the sticks will now be explained. As shown in FIG.6, the front stick (4) is inserted into the upper opening of the rear stick (3) by rotating the sticks (3) and (4) relatively. In the folded state, middle part (29) of the front stick (4) is held between the side walls (21) of the rear stick (3). The step sides (18) of the front stick (4) touch the straight verge (15) of the rear stick (3). The curved steps (19) of the front stick (4) touch the curved verges (16) of the rear stick (3).
The hair-planted part (2) is received in the case part (5) of the rear stick (3). The state of the hair-planted part (2) in the case part (5) is important.
As shown in FIG.7, the hair edge is inwardly reformed in the longitudinal direction by the case part (5). The hair edge of the front end is backwardly pushed by the slanting case front wall (25). The hair edge of the rear end is forwardly pushed by the slanting case rear wall (24). By the slanting case walls the hair edge is inwardly reformed in the folded state.
To assure the effect of reformation, some conditions are required regarding the slant walls and the length of the hair-planted part (3). "A" denotes the longitudinal distance between the case front wall (25) and the case rear wall (24) at a higher level. "C" denotes the longitudinal distance between the case front wall (25) and the case rear wall (24) at the bottom. "E" denotes the length of the hair-planted part (2). A, C and E must satisfy the inequality
A > E > C (1)
Furthermore another requirement shall be satisfied. "x" denotes the distance between the center of the case part (5) and the center of the connection hole (7). "y" denotes the center of the hair-planted part (2) and the pivot (6). "x" must nearly be equal, namely
x ≅ y (2)
More strictly speaking , x, y, A, C and E must satisfy the inequalities,
| x - y | ≦ | A - E | (5)
and
| x - y | ≦ | E - C | (6)
FIG.8 shows an enlarged vertically sectioned view of the hair-planted part and the case part. In this sectional view the hair edge is pushed inwardly by the slanting surfaces of the case side walls (22).
Thus the case side walls (22) prevent the hair edge from bending outwardly. The hair edge is reformed also in the vertical direction.
"B" denotes the inner width of the case part (5) at a higher level. "D" denotes the inner width of the case part (5) at the bottom. "F" denotes the width of the hair-planted part (2). To assure the effect of vertical reformation, B, D and F must satisfy the inequality
B > F > D
The reformation of hair edge continues as long as the toothbrush is in the folded state. Usually the toothbrush is left in the folded state. Thus even if inward bending of hair edge is slight, the reformation effect is sufficient.
The toothbrush in the folded state is very short. The length is nearly half of the ordinary toothbrush. Thus the folded toothbrush is convenient to carry with. The folded state is secured by the friction force which the side walls (21) of the rear stick (3) applies on the middle part (29) of the front stick (4).
The operation of opening is reverse to that of closing. The sticks (3) and (4) can be opened by plucking the front stick (4) out of the rear stick (3) and rotating the sticks relatively. The sticks extend around the pivots (6) and connection holes (7) as a fan.
When the rotation angle held between the front stick (4) and the rear stick (3) attains nearly 135 degrees, the claw (9) of the rear stick (3) touches the arc surface of the projection (11). The elastic piece (8) is being extruded, while the claw (9) is climbing the arc surface.
When the rotation angle increases to near 180 degrees, the claw (9) overruns the projection (11). The claw (9) grips the forehead of the projection (11). At last the sticks are fully extended. The sticks are aligned along a straight line. The end wall (26) of the front stick (4) touches the end (27) of the rear stick (3). Therefore further relative rotation is forbidden. The extended state is secured by the grip of the claw (9) on the projection (11).
One of advantages of the invention is to prolong the lifetime of toothbrush. The case part prevents the hair edge from bending outward in the folded state. The hair edge is reformed automatically.
Another advantages of the invention is to provide a toothbrush which is unlikely to hurt gums, because the hair edge is not bent outward. The toothbrush is excellent from the standpoint of oral hygiene.
Other advantage of the invention is to provide a toothbrush convenient for carrying with, because it can be folded to about half length of an ordinary toothbrush.
Besides, the toothbrush is also excellent from an aesthetic standpoint of view, if the front stick is white and the rear stick is tinted in colors other than white - blue, green or red.

Claims

(1) A toothbrush comprising a front stick with both ends having pivots on one end, a hair-planted part planted on another end of the front stick, an upward opened rear stick with both ends having connection holes on one end for connecting the pivots therein, and a case part shaped on another end of the rear stick, the case part having slanting case side walls, a case bottom wall, a case rear wall and a slanting case front wall, wherein the front stick is rotatably connected to the rear stick by the pivots and the connection holes, the front stick and rear stick can be folded or extended by rotating the sticks around the plvots and connection holes, in the extended state the front stick and the rear stick are aligned along a straight line, in the folded state the hair-planted part of the front stick is enclosed by the case part of the rear stick, characterized in that in the folded state, the hair edge of the hair-planted part is inwardly reformed at least by the slanting case side walls and the slanting case front wall.
(2) A toothbrush as claimed in claim (1), wherein the rear stick includes an elastic piece formed on the end near the connection holes, the elastic piece includes a claw, the front stick includes a projection on the end near the pivots and in the extended state the claw of the rear stick grip the projection of the front stick.
(3) A toothbrush as claimed in claim (2), wherein the upward opened rear stick has side walls and a bottom wall, middle part of the front stick has step sides and the middle part of the front stick is partially held between the side walls of the rear stick in the folded state.
(4) A toothbrush as claimed in claim (3), wherein the case rear wall is also slanting for reforming the rear hair edge inwardly.
(5) A toothbrush as claimed in claim (4), wherein the width B of the upper case part, the width D of the lower case part and the width F of the hair-planted part satisfy the inequality
B > F > D
(6) A toothbrush as claimed in claim (5), wherein the longitudinal length A of the upper case part, the longitudinal length C of the lower case part and the longitudinal length E of the hair-planted part satisfy the inequality
A > E > C
(7) A toothbrush as claimed in claim (6), wherein the case bottom wall has ventilating holes.
(8) A toothbrush as claimed in claim (7), wherein the front stick includes a cavity formed on an upper half surface near the pivot.
(9) A toothbrush as claimed in claim (8), wherein the front stick is white and the rear stick is colored with a color except white.
(10) A toothbrush as claimed in claim (9), wherein the rear stick includes straight verges originating near the pivot, curved verges continuing downward from the straight verges and straight case verges continuing from the curved verges.