Note: Descriptions are shown in the official language in which they were submitted.
20~7~a
This invention relates to a toothbrush, and particularly
to a toothbrush capable of sufficiently brushing its user's
teeth up to the innermost molars.
Heretofore, various toothbrushes have been known, e.g.
those in which a grip portion and a head portion with
bristles implanted therein are arranged in alignment, those
in which a head portion with bristles implanted therein is
bent or curved relative to a grip portion, and the like.
However, in the toothbrushes in which the head portion
and the grip portion are in alignment, there is the fear that
when the cheek and tongue sides of the molar teeth are
brushed, insertion of the toothbrush is interfered by the
cheek, front teeth, tongue, etc. Therefore, the users of
toothbrushes, particularly those who are not yet good at
using a toothbrush, were frequently obliged to stop brushing
the molar teeth before they have been sufficiently cleaned.
Even in the case of toothbrushes in which the head por-
tion with bristles implanted therein are bent or curved rela-
tive to the grip portion, although the insertion of the
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toothbrush becomes more or less easier, there is the fear
that when the molar teeth are brushed, the insertion of the
toothbrushes is interfered by the cheek.
Further, in the conventional toothbrushes, because the
heights of the bristles are arranged to be generally equal to
each other, the toothbrushes hardly reach the inner part of
the user's buccal cavity and therefore, it was difficult to
sufficiently brush the teeth up to the innermost molars. In
view of this inconvenience, there is proposed a toothbrush in
which the heights of the bristles implanted in the distal
area of the head portion are set shorter than the heights of
thé bristles imPlanted in the grip side area of the head por-
tion (see Japanese Utility Model Early Laid-open Publication
No. Sho 56-67173 and Japanese Utility Model Early Laid-open
Publication No. Sho 56-171728, etc.)
However, in the above toothbrush, since the bristles im-
planted in the distal area of the head portion are merely set
short in height, it sometimes happened depending on the
user's way of brushing that the toothbrush does not reach
sufficiently up to the innermost molars, thus resulting in
insufficient brushing of the innermost molars. Where the
heights of the bristles are set short, so that the toothbrush
may reach up to the innermost molars, the flexibility of the
bristles is degraded.
7 9 ~
A general object of the present invention is to provide
a toothbrush capable of sufficiently brushing the teeth up to
the innermost molars.
A concrete object of the invention is to provide a
toothbrush, in which a head portion with bristles implanted
therein can be srnoothly inserted into the user's buccal
cavity up to the molar teeth when the teeth are brushed.
Another concrete object of the invention is to provide a
toothbrush, in which the fle~ibilitY of bristles implant~d in
a distal area of its head portion is not degraded and the.
bristles can reach.the innermost molars so as not to leave~
the innermost molars~in insufficiently brushed states and so
as to sufficientlY brush the teeth up to the innermost
molars.
According to the present invention, the
toothbrush includes a grip portion, and
a head portion integrally connected with the grip portion
through a neck portion and having bristles implanted therein,
the head portion being bent or curved toward the bristles
side relative to the grip portion, the tooth brush being
characterized in that t~e head portion is further bent or
curved toward the bristles side relative to ~he neck por-
tion.
According to the present invention, in the toothbrush
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the heights of brist~es implanted in the distal area
of the head portion is shorter than the heights of bristles
implanted in the remaining area of the head portion, the
average positions of the tips of the bristles in each bristle
flock implanted in tAe distal area being generally flush
with the average positions of the tips of the bristles in
each bristle flock implanted in the remaining area, the dif-
ference in length between the highest bristle and the lowest
bristle in each bristle flock implanted in the distal area
being set within a range of from 0.8mm to 4mm and the lengths
of the bristles in each bristle flock being irregularlY set.
In the accom~anying drawings:
Fig. 1 is a side view showing a first embodiment of a
toothbrush of the present invention.
Fig. 2 is a side view showing a second embodiment of a
toothbrush of the present invention.
Fig. 3 is a side view of an exploded state showing a
third embodiment of a toothbrush of the present invention.
Fig. 4 is a partly enlarged side view showing one ex-
ample of a head portion with bristles implanted therein of a
toothbrush of the present invention.
Fig. 5 is a partly enlarged side view showing another
example of the head portion of a toothbrush of the present
invention.
2 1~ 0
Fig. 6 is a partly enlarged side view showing a further
example of the head portion of a toothbrush of the present
invention.
Fig. 7 is a partly enlarged side view showing a still
further example of a head portion of a toothbrush of the
present invention.
Fig. 8 is a partly enlarged side view showing a yet fur-
ther example of a head portion of a toothbrush of the present
invention.
Fig. 9 is a partly enlarged side view showing additional
example of the head portion of a toothbrush of the present
invention A
One embodiment of the present invention will be
described hereinafter with reference to the accompanYing
drawings.
Fig. 1 is a side view showine the first embodiment of a
toothbrush of the present invention.
The toothbrush of this embodiment comprises a griP por-
tion 1, and a head portion 2 with bristles 3 implanted in one
surface thereof and integrally connected with the grip por-
tion through a neck portion 4.
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The head portion 2 is bent or curved toward the bristles
side relative to the grip portion 1, and the head portion 2
is also bent toward the head Portion side, on which the
bristles are provided, relative to the neck portion 4.
The length of the head portion 2 is preferablY set
within a range of from 10mm to 25mm and more Preferably
within a range of from 12mm to 22mm within the aforementioned
range. If the length of the head portion 2 is less than
10mm, there is the fear that the implanting area becomes too
small and the brushing efficiency becomes unsatisfactory.
On the other hand, if it exceeds 25mm, there is the fear that
the tongue sides of the molar teeth become difficult to be
brushed.
The angle ~ 1 of bend of the head portion 2 relative to
the neck portion 4 is preferably set within a range of from S
to 15D and more preferably within a range of from 6 to 10
within the aforementioned range. If the angle ~ 1 is less
than 5 , there is the fear that the toothbrush is interfered
by the cheek when the molar teeth are brushed. On the other
hand, if it exceeds 15 , the brushing operation itself be-
comes difficult to effect.
Further, the angle ~ 2 (total angle ~ 2 including the
angle ~ 1 ) of bend or curve relative to the grip portion 1
of the head portion 1 is preferably set within a range from 7
to 30 and more preferably within a range of~from 10 to 20
2~48790
within the aforementioned range. If the angle ~ 2 is less
than 7 , there are fears that the efficiency for removing
the plaque on the molar teeth becomes low and the brushing
operation particularly for the molar teeth becomes difficult
to effect. On the other hand, if the angle ~ 2 of bend or
curve exceeds 30 , there are also the fears that the ef-
ficiency for removing the plaque on the molar teeth becomes
low and the brushing operation particularly for the molar
teeth becomes difficult to effect.
The materials composing the grip portion 1 and the head
portion 2 are not particularly limited but those which are
normally used for toothbrushes are good enough. For ex-
ample, it may be composed of AS (acrylonitrile-styrene
resin), ABS (acrylonitrile-butadiene-styrene resin), PP
(polypropylene resin), PC (polYcarbonate resin), PBT
(polybutyleneterephthalate resin), propionate, thermoplastic
elastomer, etc.
The materials composing the bristles 3 are not limited,
either. Those which are used for bristles of conventional
toothbrushes can be used.
The tip of each bristle may be formed in a rounded
shape.
According to a toothbrush of this embodiment with the
above-mentioned constitution, even a beginner of brushing ex-
ercise of a toothbrush can easily insert the head portion 2
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into the inner side of the bucca] cavity in order to suffi-
ciently brush the cheek and tongue sides of the molar teeth.
Therefore, there is no fear that the molar teeth are
left non-brushed and plaque on the molar teeth can be suffi-
ciently removed.
The Table-1 to follow shows the data obtained through a
questionaire about the easiness of the use of the toothbrush
according to the first embodiment when the angle 0 1 of bend
or curve is set to 5 , 10 and 15 and the other angle ~ z
of bend or curve is set to lO , 20 and 30 . Similarly,
the Table-2 shows the results of removal of artificial plaque
under the above-mentioned angles of bend or curve.
For comparison purpose, there are also shown in the
Table-1 and Table-2 the data obtained through a questionaire
on the conventional toothbrushes and the results of removal
of artificial plaque thereof, wherein the head portion and
neck portion are formed straight so that they are aligned on
a same line and the head and neck portions are inclined by 10
, 20 and 30 relative to the grip portion.
2 ~ 9 0
Table-l n-100
S S S 10 10 10 15 15 0 0
~1 2 1O 20 30 10 20 30 20 3010 20~ 30
Easiness of brushing vhen front
teeth are beins brushed (X)57 42 30 62 S0 31 47 3654 36 29
Easiness of brushing ~hen molar
teeth are being brushed (X~72 B7 68 64 84 70 76 8061 68 65
Table-2
5O 5O 1 oO 1 oO 1 oO 1 5O1 5 0 0 0
2 1O 20 30 10 20 30 20 3010 20 30
..
RatiD of artlficial Plaque62.1 71.558.0 59.4 76.2 63.7 72.6 59.458.6 69.2 55.7
remwal (X) (n-5) +4.6 +2.9 +3.2 +5.0 +3.9 +4.5 +6.1 +3.4 +3.8 +5.0+2.9
2~4~7~0
As apparent from the above Table-l and 1able-2, in the
case of the conventional toothbrushes, in which the head and
neck portions are formed straight so that they are aligned on
a same line and the head and neck portions are inclined rela-
tive to the grip portion, the head portion was interfered by
the cheek, etc. and diffiCultY was encountered during the
brushing operation.
On the other hand, if the head portion 2 is bent rela-
tive to the neck portion 4 as in the first embodiment, the
ratio of removing artificial plaque was increased, the brush-
ing operation was carried out with ease, and operation per-
formance was enhanced.
.
Fig. 2 is a side view showing the second embodiment of a
toothbrush of the present invention. Like parts of Fig. 1
are denoted by like numerals and description thereof is
omitted.
In the toothbrush shown in this second embodiment, the
neck portion 4 is inclined such that its nearer part 4a to
the grip portion 1 is once curved downward relative to the
center line Q of the grip portion 1 and then the remaining
part of the neck portion 4 is raised up to a position above
the center line Q.
By virtue of the foregoing arrangement, in addition to
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the same effect available as in the first embodiment, there
can be obtained such effect as that even in the case of the
angle ~ 2 of bend or curve being set near to 30 , there is
no fear that the height of the toothbrush from the grip POr-
tion 1 to the distal end of the head portion 2 becomes too
high.
A toothbrush of the present invention is not limited to
those in which the head portion 2 is integrally formed with
the grip portion 1 as shown in the first and second embodi-
ments.
For example, it may be applied to the one as shown in
the third embodiment in which a neck portion 4 and a head
portion 2 are removablY attached to a grip portion 1 of an
electric toothbrush in which a driving source e.g. a motor
6, etc. is built in the grip portion 1. In Fig. 3, the
numeral 7 denotes a vibrator adapted to incur vibration to
the head portion 2 and to interconnect lhe grip portion 1 and
the neck portion 4, and the symbolic numeral 4b denotes a
recess formed in one end face of the neck portion 4 into
which the vibrator 7 is removably engaged.
The present invention may also be applied to a
toothbrush of the type in that a head portion 2 and a neck
portion 4 are collapsibly connected to a grip portion 1
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through a pin.
A toothbrush of the present invention including those of
the first, second and other embodiments, becomes more
favorable by constituting the head portion in a particular
way. Accordingly, the head portions to be described
hereinafter can be employed as the head portions in the
first, second and other embodiments which are already
descri.bed above.
Several embodiments of a head portion of a toothbrush
will be described with reference to Figs. 4 through 9. In
Figs. 4 through 9, different reference numerals are used even
for identical or similar parts of Figs. 1 through 3.
In the toothbrush of the embodiment shown in Fig. 4, the
heights of bristles 15a implanted in a distal area 12a of a
head portion 12 are set shorter than the heights of bristles
16a implanted in the remaining area (the neck portion 14 side
area of the head portion 12, hereinafter r-e.ferred to as the
"basal area" 12b) of the head portion 12, the average posi-
tions of the tips of the bristles in each bristle flock 15
implanted in the distal area 12a is generallY flushed with
the average positions of the tips of the bristles in each
bristle flock 16 implanted in the basal area 12b, the dif-
ference in length between the highest bristle 15a and the
2~4~79~
lowest bristle 15a in each bristle flock 15 irnplanted in dis-
tal area 12a is set within a range of from lmm to 4mm and
preferably within a range of from l.Omm to 2.0mm, and the
lengths of the bristles 15a in each bristle flock 15 are ir-
regularly set. The distal area 12a is formed such that it
rises up to form a step relative to the basal area 12b. The
flocks 15 and 16 of the bristles 15a and 16a each comprises a
plurality (for example, 30 to 60) of bristles 15a and 16a,
respectively, which are implanted in the head portion 12.
The reasonswhY the difference in length between the
high es t bris tle 15a and th e lowest bris tle 15a in e ach
bristle flock 15 implanted in the distal area 12a is set
within a range of from lmm to 4mm and the lengths of bristles
15 in each bristle flock 15 are irregularly set within the
aforementioned range, are as follows. That is, if the
lengths of bristles 15 in each bristle flock are irregularly
set in a range shorter than lmm, it becomes almost the same
to the one in which the heights of bristles implanted in the
distal area 12a oi` the head portion 12 are merely set short,
and on the other hand, if the lengths are irregularly set
within a range longer than 4mm, the shortest bristle l5a
among the bristles 15a of each bristle flock 15 becomes un-
,able to reach the innermost molars, the gum portion, etc.
Further, the lengths of the bristles 16a in each bristle
flock implanted in the basal area 12b are preferably ir-
13
7 ~ ~
regularly set as in the lengths of the bristles 15a of eachbristle flock implanted in the distal area 12a. Further-
more, the average heights of the bristles 15a implanted in
the distal area 12a are set lOmm or less, and preferably
within a range of from 8mm to 9mm, and have a difference of
0.5mm or more and preferably within a range of from lmm to
2mm relative to the average heights of the bristles 16a im-
planted in the basal area 12b.
Moreover, the tip of each bristle 15a, 16a is preferably
formed in a rounded shape. In this case, 50% or more of a
plurality of bristles 15a, 16a adjacent to an optional
bristle are arranged not to be contacted with the rounded tip
15b, 16b of the optional bristle (in other words, the heights
of the bristles are arranged to be different). The reason
why this arrangement is necessary is that if, in adjacent to
the optional bristle, there are a plurality of bristles 15a,
16a having the heights equal to that of the optional one, the
rounded tips 15b and 16b are contacted with each other and
the tips of the bristles 15a and 16a are spread. In other
words, the arrangement is made in order to avoid an occur-
rence of this unfavorable situation. The diameter of each
of the bristles 15a, 16a excepting the tips thereof is
preferably set from 6/1000 to 15/1000 inches. If it is less
than 6/1000 inches, the bristle ]5a, 16a lacks stiffness and
as a result, there is the fear that the force to be incurred
2~790
to the teeth during the brushing operation is not effective
as the force for removing the ~laque and for massaging the
gum portion. On the other hand, if it exceeds 15/1000
inches, the bristles 15, 16b themselves become too stiff and
a feel to the gum portion becomes unfavorable. The
diameters of the rounded tips 15b, 16b of the bristles 15a,
15b are set larger bY about 1.1 to 2.5 times the diameters of
the remaining portions (the portions excepting the tips) of
the bristles 15, 16a, and Preferably by 1.2 to 2.0
times. If they are less than 1.1 times, they are substan-
tially unchanged from the conventional toothbrush in which
the rounded tips 15b, 16b are not formed and the effects are
insufficient. On the other hand, if they exceed 2.5 times,
the tips of the bristles are spread, thus providing an un-
satisfactory appearance. The configuration of the rounded
tips 15b, 16b are not necessarily limited to a rounded shape
but it maY be an elliptical shape, a nail shape, a cubic
shape having four rounded corners, etc.
According to a tooth brush shown in Fig. ~, having the
head portion constituted in the manner as mentioned above,
the heights of the bristles 15a in the distal area 12a of the
head portion 12 are set shorter than the heights of the
bristles 16a in the basal area 12b of the head portion 12,
the difference in length of the longest and shortest bristles
in each bristle flock 15 is set within a range of from lmm to
~a~7s~
~mm, and the lengths of the bristles 15a in each bristle
flock are irregularly set within the aforementioned range.
Accordingly, the bristles 15a do not become too stiff tlack
of flexibility~, the tips of the bristles 15a can easily en-
ter between adjacent teeth where the plaque are difficult to
be removed during the brushing operation, and the tip or tips
of one or some of the bristles 15a in each bristle flock are
readily contacted even with the innermost molars, thus ena-
bling to eliminate non-brushed teeth and to effectively
remove the plaque. Further, since the rounded portion 15b,
16b is provided to the tip of each bristles 15a, 16a, the
plaque, for example, between the enameled part of each tooth
and the upper edge of the gum portion can be scratched out
while massaging the gum portion. Furthermore, since the
heights of the bristles 16a in the basal area 12b of the head
portion 12 are set longer than the heights of the bristles
15a in the distal area 12a and the average positions of the
tips of the bristles of the respective bristle flocks 15, 16
on the entire head portion 12 are substantially flushed with
each other, a feel of the use is good.
The head portion of a toothbrush of the present inven-
tion may be constituted in the manner as shown, for example,
in Figs. 3 through 7, besides that of the embodiment shown in
Fig. ~.
To be specific, as is shown in Fig. 5, it may be
16
2 ~ 9 0
designed such that no rounded portion is provided to the tip
of each of the bristles 15a, 16a and the tips of only the
bristles 12a in each bristle flock 15 in the distal area 12a
of the head portion 12 are irregularly set within a range of
from 0.8mm to 4mm.
Further, as is shown in Fig. 6, the tips of only the
bristles 15a in each bristle flock 15 in the distal area 12a
of the head portion 12 are irregularly set within a range
from 0.8mm to 4mm and the tips of the bristles 15a are
provided with a rounded portionl5b, respectively.
Furthermore, as is shown in Fig. 7, it may also be
designed such that the distal area 12a of the head portion 12
is bent to provide a step portion between the distal area 12a
and the basal area 12b and the average positions of the tips
of the bristles in the respective bristle flocks 15, 16 on
the entire head portion 12 are substantially flushed with
each other.
Further, as is shown in Fig. 8, it may be desi~ned such
that the head portion 12 is divided into three areas, namely,
the distal area 12a, the basal area 12b and an intermediate
area 12c and formed in three steps, and the average positions
of the bristles of the respective bristle flocks 15, 16 are
substantially flushed with each other.
Furthermore, as is shown in Fig. 9, it may also be
designed such that the distal area 12a of the head portion 12
17
20~8790
is inclined and the average positions of the bristles in the
respective bristle flocks on the entire head portion 12 are
substantially flushed with each other. Further, it may be
designed such that the heights of the bristles implanted in
the distal area 12a of the head portion 12 are set shorter
than the heights of the bristles 16a implanted in the basal
area 12b of the head portion 12, the average positions of the
bristles in the respective bristle flocks 15, 16 are substan-
tially flushed with each other, the difference in length be-
tween the longest and the shortest bristles 15a in each
bristle flock 1~ in the distal area 12a is set within a range
from 0.8mm to ~mm, and the lengths of the bristles 15a in
each bristle flock 15 are irregularly set within the
aforementioned range.
18
