Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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IMPROVED MECHANICAL TOOTHBRUSH
HAVING OPPOSED DUAL HEADS
AND HAVING OSCILLATORY MOVEMENT
FIELD OF THE INVENTION:
This invention relates to electric toothbrushes, sometimes referred to as
mechanical toothbrushes, and is more particularly directed to a portable hand-
held,
electrically powered, mechanical toothbrush. Specifically, a novel toothbrush
head is
disclosed.
BACKGROUND OF THE INVENTION:
The use of manual toothbrushes has, of course, been know for many years.
Indeed, the use of mechanical toothbrushes, typically those which are
electrically driven,
has been known for a number of years. The purpose, in any event, is to clean
the teeth,
usually with a toothbrush which comprises a plurality of bristles that are
used in
conjunction with a dentifrice. Very often, the dentifrice is mildly abrasive.
The dental profession has propounded, for many years, a technique known as the
"Bass Technique" which, if properly performed, is said to achieve superior
results in
terms of cleaning one's teeth using a manual toothbrush. Essentially, the Bass
Technique
requires the user to position a manual toothbrush over a zone of the teeth,
and then to use
very short stokes so as to more or less vibrate the brush at that zone where
the brush has
been located. This short-stroke brushing should continue for a period of time -
typically,
twenty strokes to forty strokes - so as to remove any foreign material from
that zone.
The brush is then repositioned and typically another twenty to forty short
strokes are
performed. Because each zone is very small, the Bass Technique can be very
time
consuming. Moreover, since it is a requirement that the strokes be very short
which, in
turn, requires excellent muscle control, exercising the Bass Technique can be
very tiring.
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The theory is that, at the end of any given stroke, the bristles will flex so
as to
become oriented in such a manner that the ends of the bristles point generally
away from
the direction of the travel of the bristles across the teeth. However, at the
beginning of
the next stroke, in the opposite direction, the still-flexed bristles will
then be pointed in
the direction of the stroke and this may cause the bristle to chisel the
foreign material
away from the teeth for a moment before the bristle again begins to flex so as
to sweep
across the surface of the tooth in the zone where it is located.
However, a more efficacious manner for brushing teeth comprises a variation of
the Bass Technique, whereby oscillatory movement is imparted to a toothbrush.
Of
course, such oscillatory movement is not capable of being executed manually.
A purpose of the present invention is to provide an electro-mechanical
toothbrush
- that is, an electrically driven, mechanical toothbrush, most typically
referred to as an
electric toothbrush - which will permit the user to perform a tooth cleaning
procedure
which improves upon the Bass Technique by imparting oscillatory movement to
the
toothbrush. In other words, by using the toothbrush of the present invention,
the user
will be able to locate the toothbrush at a given zone for a short period of
time, while
executing a plurality of oscillatory motions of the toothbrush to clean the
teeth, and then
move on to the next zone, thus achieving efficient cleaning of the teeth.
Apart from the removal of leftover food particles and the like, a particular
purpose for cleaning the teeth is to remove plaque build-up from the teeth.
Typically,
when using a manual toothbrush, plaque build-up is removed much more easily
from the
buccal surfaces of the teeth than from the lingual surfaces of the teeth, with
relatively
good foreign material removal from the occlusal surfaces of the teeth also
being
achieved.
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One development that has occurred in respect of manual toothbrushes is the
provision of twin-headed brushes, whereby the lingual and buccal surfaces of
the tooth
can be scrubbed using the bristles of the brush at the same time, with the
same stroking
action of the brush.
As to electric toothbrushes, most electric toothbrushes provide groups of
bristles
which are located in concentric circles, where the brush head thus provided is
rotated or,
more usually, it is reciprocally rotated. The co-pending application noted
above teaches
a toothbrush having twin heads to which a lengthwise reciprocating linear
motion is
imparted.
DESCRIPTION OF THE PRIOR ART:
Several typical prior art toothbrushes are now described. Among them are
several
manual toothbrushes which comprise dual, opposed bristle heads. They include
PORPER United States Design patent No. D259,977, issued July 28,1981, which
reveals
an early design for a toothbrush having opposed bristle heads.
Another manual toothbrush which is adapted for cleaning multiple sides of the
teeth at the same time is shown in WAGNER United States patent No. 5,327,607,
issued
July 12, 1994. The toothbrush disclosed in that patent includes further
bristles which
extend from the spine of the toothbrush so as to contact the occlusal surfaces
of the teeth
at the same as the buccal and lingual surfaces of the teeth are being
contacted while the
toothbrush is in use.
A typical prior art electric toothbrush is disclosed in AMAKASU United States
patent No. 5,359,747, issued November 1,1994. Here, a brush member of the
toothbrush
is given reciprocal motion in the axial direction while, at the same time, the
brush
member itself is given a rotary motion. The rotary brush member is rotatably
mounted
on the end of an attachment connected to a drive shaft, and the reciprocating
motion in
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the axial direction thereof is converted into a rotary motion and transmitted
to the rotary
brush member by a second transmission mechanism.
Another typical prior art electric toothbrush is disclosed in BAUMAN United
States patent No. 5,353,460, issued October 11, 1994. Here, there is a pair of
brush
elements with driving mechanism which drives one of the brush elements in
oscillation,
with linkage between the brush elements so that the second brush element is
also driven
in oscillation. The two brush elements are preferably oscillated in opposite
directions.
However, the two brush elements can only contact any one surface of the teeth
at a time.
A mechanical toothbrush which is said to effectively replicate the Bass
Technique
is STANSBURY United States patent No. 5,259,083, issued November 9, 1993. This
power driven mechanical toothbrush comprises a plurality of tuft blocks which
are
mounted on a cam shaft. The tuft blocks are received in sliding relation in a
toothbrush
head member, and each tuft block slides linearly in a direction parallel to
the longitudinal
tuft axis as it is guided by guide rails within the head member between a
retracted
position and an extended position. The tuft blocks are each driven by the
rotatable cam.
In use, the tuft bristles are brought into contact with the teeth by the user,
before the
respective tuft block reaches its extended position, so as to thereby flex the
bristles and
to cause a lateral motion of the distal end of the bristles along the surface
of the teeth.
This whipping action of the ends of the bristles causes a wiping action across
the surface
of the teeth while, at the same time, causing a chiselling action by the ends
of the bristles
against the teeth, so as to thereby remove foreign material away from the
teeth in the
region where the bristle chiselling action occurs.
Finally, DAUB United States patent No. 5,027,463, issued July 2, 1991, teaches
a toothbrush which may be used for simultaneously brushing and cleaning the
occlusal,
lingual, and buccal surfaces of the upper and lower teeth of the user. Here, a
bristle
support member is provided which anchors bristles which extend from the
opposite
surfaces thereof. The bristles are arranged so that the central rows of
bristles are straight
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while the intermediate and outer rows of bristles on each of the opposed
surfaces of the
bristle support member are curved. The straight bristles will engage the
occlusal surfaces
of the teeth, while the intermediate and outer rows will engage the lingual
and buccal
surfaces of the teeth.
SUMMARY OF THE INVENTION:
In accordance with one aspect of the present invention, there is provided an
electric toothbrush which comprises a power handle portion and a brush head
portion.
The power handle portion is adapted to provide a housing for an electric motor
and for
a driving mechanism which is located at a first end of the power handle
portion.
The driving mechanism is powered by the electric motor, and the electric motor
has a longitudinal axis. The brush head portion of the toothbrush also has a
longitudinal
axis which is offset by a first offset distance with respect to the
longitudinal axis of the
electric motor.
The brush head portion of the toothbrush of the present invention is removably
attachable at a first end thereof to the first end of the power handle
portion, and the brush
head portion comprises a pair of opposed bristle head portions arranged so as
to present
two groups of opposed bundles of bristles disposed substantially
perpendicularly each
to the other. Each of the groups of bundles of bristles on each respective
bristle head
portion comprises a plurality of rows and a plurality of columns of bristle
bundles, where
the rows of bristle bundles are aligned parallel to the longitudinal axis of
the brush head,
and the columns of bristles are aligned perpendicular the longitudinal axis of
the brush
head.
The bristles in each bundle in each row of bristle bundles on each bristle
head
portion are substantially equal in length. The length of the bristles in the
respective row
of bristle bundles on each bristle head portion which is closest to the
longitudinal axis
of the brush head portion is shorter than the length of the bristles in the
respective row
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of bristle bundles on each bristle head portion which is furthest away from
the
longitudinal axis of the brush head portion. Moreover, the lengths of the
bristles in each
respective row of bristle bundles on each bristle head portion are
progressively longer in
each row of bristle bundles which is further away from the longitudinal axis
of the brush
head portion than an adjacent row of bristle bundles which is closer to the
longitudinal
axis of the brush head portion.
Typically, the outer ends of the respective row of bristle bundles which is
closest
to the longitudinal axis of the brush head portion, on each of the bristle
head portions,
are spaced less than 0.100 inch from the outer ends of the respective opposed
row of
bristle bundles on the other bristle head portion.
The driving mechanism of toothbrushes in keeping with the present invention
comprises a motion translation means for translating rotational driving power
from the
electric motor to oscillatory motion delivered to the brush head portion. The
driving
mechanism further comprises a drive shaft which is disposed on the
longitudinal axis of
the brush head portion of the toothbrush. The drive shaft is adapted to
deliver oscillatory
driving power from the motion translation means to the brush head portion.
The drive shaft of the driving mechanism is received in a socket in the brush
head
portion of the toothbrush of the present invention, in a manner so as to
receive the drive
shaft in position along the longitudinal axis of the brush head portion.
Accordingly, rotational motion of the flywheel is translated by the motion
translation means into oscillatory motion of the drive shaft, so as to provide
oscillatory
movement to the pair of opposed bristle head portions of the brush head.
In keeping with a particular feature of the present invention, as described in
greater detail hereafter, the brush head portion comprises two matched halves,
and the
drive pin. Each of the two matched halves comprises a respective one of the
bristle head
portions and a respective half of an intermediate arm portion of the brush
head portion.
Each respective matched half is formed with a portion of the socket at the
first end
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thereof. The socket portion is disposed on the longitudinal axis of the brush
head
portion. As noted, the drive shaft is received in the socket so that
oscillatory driving
motion is directly transmitted to the brush head portion.
A further aspect of the present invention is to provide such an electric
toothbrush
as is described above, where the brush head portion further comprises a collar
portion at
the first end thereof, which collar portion is adapted to be removably
attachable to the
first end of the power handle portion. The opposed bristle head portions of
the brush
head portion are disposed at the end of an intermediate arm portion thereof,
which end
is opposed to the first end of the brush head portion. The intermediate arm
portion is
accommodated within the collar portion in such a manner that the drive shaft
is received
in the socket while being maintained in position on the longitudinal axis of
the brush
head. This permits replacement of the brush head by a new brush head, or by a
different
brush head for use by a different user of the toothbrush mechanism of the
present
application.
A purpose of the present invention is to provide such an electric toothbrush
as
described above, which can be used to effectively impart the improved version
of the
Bass Technique to the toothbrush heads and, thereby, to achieve better tooth
cleaning
results.
Finally, a purpose of the present invention is to bring an electric toothbrush
to the
market which can be used for very effective cleaning of the teeth, but which
can be
brought to the market at relatively low cost compared with many of the prior
art electric
toothbrushes, due to the relatively uncomplicated structure of the electric
toothbrush
hereof.
BRIEF DESCRIPTION OF THE DRAWINGS:
The novel features which are believed to be characteristic of the present
invention, as to its structure, organization, use and method of operation,
together with
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further objectives and advantages thereof, will be better understood from the
following
drawings in which a presently preferred embodiment of the invention will now
be
illustrated by way of example. It is expressly understood, however, that the
drawings are
for the purpose of illustration and description only and are not intended as a
definition
of the limits of the invention. Embodiments of this invention will now be
described by
way of example in association with the accompanying drawings in which:
Figure 1 is a simplified perspective view of a toothbrush in keeping with the
present invention, showing several typical power components thereof in ghost
fashion;
Figure 2 is a simplified perspective view of a typical drive mechanism in
keeping
with the present invention;
Figure 3 is similar to Figure 2, showing a portion thereof to a greater scale,
and
with additional detail;
Figures 4A, 4B, 5, and 6 are end views of the brush head portion of the
toothbrush, and of the brush head portion of the toothbrush being in contact
with a
typical tooth at the rear of the mouth, and in contact with a typical tooth at
the front of
the mouth, respectively; and
Figures 7A, 7B, 7C, and 8A, 8B, and 8C are end, plan, and elevational views,
respectively, of two typical configurations of the bristle head portion of a
toothbrush in
keeping with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS:
The novel features which are believed to be characteristic of the present
invention, as to its structure, organization, use and method of operation,
together with
further objectives and advantages thereof, will be better understood from the
following
discussion.
In a paper published in the Journal of Clinical Paediatric Dentistry, Vol. 19,
No.
1, Fall 1994, ALMAJED describes the superior results obtained by thirty
patients ranging
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in age between 6.6 and 18 years of age, using a double-headed toothbrush,
compared
with an ordinary manual toothbrush, with and without dentifrice. The double-
headed
toothbrush is identified with the trade mark TWINBRUSHTM, provided by
Prevention
Health Products, Inc. of Somers, New York, U.S.A., and being that which is
identified
in Porper United States Design patent No. D259,977, noted above. The results
of the
tests were such that, even with manual manipulation of the double-headed
toothbrush,
it was significantly more effective in removing plaque than the single-headed
toothbrush.
The technique used by the patients is identified as being a modified Bass
Technique. The
results obtained were statistically significant.
As noted above, a feature of the present invention is essentially to provide a
double-headed brush head which effectively replicates that which is shown in
the Porper
design patent, but with a modified arrangement of rows and columns of bunches
of
bristles in a preferred embodiment and, in any event, arranged in such a
manner so as to
be mechanically driven as the brush head portion of an electric toothbrush.
A typical configuration of electric toothbrush, in keeping with the present
invention, is now described with reference first to Figure 1. The electric
toothbrush 10
comprises a power handle portion 12 and a brush head portion 14. Typically,
there is
included in the power handle portion 12 an electric motor 16 and a driving
mechanism
18, which is driven by the electric motor 16. It will be noted that the
driving mechanism
18 is located at or near a first end 20 of the power handle portion 12. It
will also be noted
that the power handle portion 12 has a longitudinal axis M, which is in fact
the
longitudinal axis of the electric motor 16.
Typically, the electric motor 16 is a direct current motor. Even more
typically,
the direct current motor is powered by a battery 24, which is usually a
rechargeable
battery. However, it is evident that the electric motor 16 might also be an
alternating
current motor; or even that the battery 24 might be replaced by a power supply
circuit
providing low voltage direct current power to the electric motor, whereby the
electric
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toothbrush 10 may be plugged directly into a suitable receptacle. All of those
matters are
outside the scope of the present invention.
In keeping with the present invention, the driving mechanism 18 includes a
drive
shaft 26, which has its own longitudinal axis B. The drive shaft 26 is
arranged,
particularly in a manner described in greater detail hereafter, for coupling
to the brush
head portion 14 of the electric toothbrush of the present invention. The
longitudinal axis
B is also the longitudinal axis of the brush head portion 14 of the electric
toothbrush of
the present invention.
The drive shaft 26 is driven by the electric motor 16 in a manner described
hereafter, so as to effect an oscillatory motion of the drive shaft, while it
remains in place
on the longitudinal axis B. That oscillatory motion will, as described
hereafter, result in
a concomitant oscillating movement of the brush head portion 14 in a manner as
shown
by double-headed arrow 32.
The brush head portion 14 is removably attachable at a first end 36 from the
first
end 20 of the power handle portion 12.
Turning now to Figures 2 and 3, the following discussion is particularly
directed
to the drive mechanism 18 and its relationship to the brush head portion 14,
and a typical
manner in which they are assembled. Further advantages of the assembly of the
brush
head portion 14, in keeping with a preferred embodiment of the present
invention, will
be described hereafter.
In general terms, the driving mechanism 18 comprises a motion translation
means
100. The generalities of the motion translation means 100 are that rotational
driving
power from the electric motor 16 is translated to oscillatory motion delivered
through the
drive shaft 26 to the brush head portion 14. Motion translation means which
serve such
purposes are well known in the prior art in different areas than those of the
present
invention; but a particularly effective motion translation means is shown in
some detail
in Figures 2 and 3. It is to be noted, of course, that the longitudinal axis B
of the brush
CA 02324816 2000-10-31
head portion 14 is offset from the longitudinal axis Mof the electric motor
16, by a first
distance indicated by arrows 102 in Figures 1 and 3. Since the drive shaft 26
is disposed
on the longitudinal axis B of the brush head portion 14, it is necessary for
the driving
mechanism 18 to deliver the oscillatory driving power to the brush head
portion on the
longitudinal axis B.
Further details of a typical drive shaft 26 are shown in Figure 3.
Specifically, it
will be noted that one end of the drive shaft - the end which is furthest from
the driving
mechanism 18 - is configured or shaped in such a manner that it will impart
oscillatory
motion to the brush head portion 14. In figure 3, that portion 104 of the
drive shaft 26
is shown having a square configuration; it might also have a rectangular,
hexagonal, or
blade-type configuration. In any event, examination of Figure 3 will indicate
that the
drive shaft 26 is received in a socket 106 which is formed in the brush head
portion 14,
so as to receive the drive shaft 26 in such a manner that the drive shaft 26
is secured in
position along the longitudinal axis B.
It should be noted that, in any event, the connection between the drive shaft
26
and the brush head portion 14 is such as to preclude any rotational slippage
therebetween.
Accordingly, an appropriate detachable connection - as discussed hereafter -
between
the drive shaft 26 and the brush head portion 14 is as indicated in Figure 3.
Obviously,
however, any plug and socket or blade and slot connection may be made, where
the plug
and socket are appropriately shaped, or the blade and slot are appropriately
shaped, so
that a plug or blade may be slipped into a socket or slot, or the socket or
slot may be
slipped over the plug or blade. Accordingly, the socket or slot may be formed
in either
of the drive shaft 26 or the brush head portion 14, with the mating plug or
blade being
formed in the other of the drive shaft 26 or the brush head portion 14 for co-
operating
fitment therewith.
Thus, and in any event rotational motion from the motor 16 is translated into
oscillatory motion of the drive shaft 26. Because the portion 104 of the drive
shaft 26
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is not round, neither is the socket 106 into which it is fitted, oscillatory
motion is thereby
imparted to the brush head portion 14 of the toothbrush of the present
invention; and, as
noted hereafter, thereby oscillatory movement is imparted to the pair of
opposed bristle
head portions of the brush head portion 14.
A more specific embodiment of a particular driving mechanism, in keeping with
the present invention, is shown in Figures 2 and 3. Here, the motor 16 is
shown to have
a drive shaft 110 on which a flywheel 112 is mounted. The flywheel 112 has a
rotational
axis which is coincident with the longitudinal axis M of the electric motor
16.
However, mounted on the flywheel 112 there is a drive pin 114, and the drive
pin
114 rotates with the flywheel 112. There is also a cam block 116 which has
slot 118 at
a first end thereof, into which the end of the drive pin 114 which is remote
from the
flywheel 112 is inserted.
It is important to note that the drive pin 114 has a longitudinal axis P,
which is
offset from the longitudinal axis M of the electric motor 16. Clearly, as
indicated in
Figure 3, in particular, the amount of offset of the longitudinal axis B of
the drive pin 114
is less than the offset indicated by arrows 102 between the longitudinal axis
B of the
brush head portion 14 and the longitudinal axis M of the electric motor 16.
Obviously, as the flywheel 112 rotates, the end of the drive pin 114 moves
back
and forth within the slot 118, causing the cam block 116 to swing from side to
side, and
thereby imparting an oscillatory movement to the drive shaft 26.
Accordingly, since the end 104 of the drive shaft 26 is received in the socket
106
- or there is such other connection which is such as to preclude rotation
slippage between
the drive shaft 26 and the brush head portion 14, as noted above - the
relationship
between the drive shaft 26 and the brush head portion 14 is such that
oscillatory motion
transfer will be attained. Thus, oscillatory movement of the brush head
portion of the
toothbrush in keeping with the present invention will occur.
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Typically, the amount of oscillatory motion imparted by the drive shaft 26 to
the
brush head portion 14 and the bristle head portions thereon, as described
hereafter, is in
the range of the 3° to 10° - that is, 1.5° to 5°
from each side of a neutral position. An
oscillatory motion in the range of from 5° to 6° has been found
to be quite effective.
Likewise, the rate of oscillatory movement of the drive shaft 26 is typically
in the
range of from 1,000 to 3,000 reciprocations per minute. Again, 1,500 to 2,000
reciprocations per minute has been found to be quite effective.
The brush head portion 14 comprises a pair of opposed bristle head portions 40
and 42. The bristle head portions 40 and 42 are arranged so as to present two
groups of
opposed bundles of bristles, indicated at 44 and 46; and the groups of opposed
bundles
of bristles 44 and 46 are disposed substantially perpendicularly each to the
other as
shown particularly in Figure 4A and Figure 4B.
Obviously, Figure 4B shows the effect of the oscillatory motion of the bristle
head portions 40 and 42. One position of those heads is shown in dotted line
in Figure
4B.
Each of the groups of bundles of bristles on each of the respective bristle
head
portions 40 and 42 comprises a plurality of rows and a plurality of columns of
bristle
bundles. For example, Figure 7B shows four rows and four columns of bristle
bundles,
whereas Figure 8B shows three rows and four columns of bristle bundles. It is
obvious,
therefore, that the rows of bristle bundles are aligned parallel to the
longitudinal axis B
of the brush head portion 14, and the columns of bristle bundles are aligned
perpendicular to the longitudinal axis B of the brush head portion 14.
Moreover, it is seen in each of Figures 4A, 4B, 7A, and 8A, in particular,
that the
bristles in each bundle in each row of bristle bundles on each bristle head
portion 40 or
42 are substantially equal in length. Still further, it is evident from an
inspection of the
Figures of drawings, particularly Figures 4A, 4B, 7A, and 8A, that the length
of the
bristles in the respective row of bristle bundles on each of the bristle head
portions 40
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and 42 which is closest to the longitudinal axis of the brush head portion 14,
is shorter
than the length of the bristles in the respective row of bristles bundles on
each bristle
head portion 40 and 42 which is furthest away from the longitudinal axis of
the brush
head portion 14. Thus, for example, the length of the bristle bundles 72 shown
in Figure
7A is shorter than the length of each of the bristle bundles 78. The same
conditions
apply with respect to bristle bundles 82 and 86 shown in Figure 8A.
Still further, the lengths of the bristles in each of the intervening rows of
bristle
bundles on each bristle head portion are progressively longer in each row of
bristle
bundles which is further away from the longitudinal axis of the brush head
portion than
an adjacent row of bristle bundles which is closer to the longitudinal axis of
the brush
head portion. Thus, the length of the bristle bundles 72 is shorter than the
length of the
bristle bundles 74 which, in turn, is shorter than the length of the bristle
bundles 76,
which is shorter again than the length of the bristle bundles 78, all as seen
in Figure 7A.
Likewise, the length of the bristle bundles 84, shown in Figure 8A, is
intermediate to the
lengths of the bristle bundles 82 and 86.
Typically, the longest bristles 78 or 86 will range in length from about 0.375
inch
up to about 0.45 inch, although those dimensions are exemplary only. Also, as
typical
examples, the length of a bristle head portion having four columns of bristle
bundles may
be slightly less than one-half inch; whereas the width of a bristle head
portion having
four row of bristle bundles, as shown in Figure 7B, might be in the range of
0.45 inch,
while the width of a bristle head portion having only three rows of bristle
bundles, such
as that shown in Figure 8B, may be in the range of 0.365 inch.
As will be described in greater detail hereafter, the inner rows of bristle
bundles
- that is, the rows of bristle bundles which are closest to the longitudinal
axis of the brush
head portion 14 - are arranged so that the outer ends or tips of the bristle
bundles are
nearly touching each other, as can be seen particularly in Figure 4. The gap
50 which is
between the outer ends of the respective rows of bristle bundles which are
closest to the
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longitudinal axis of the brush head portion, and each of the bristle head
portions 40 and
42, may typically be less than 0.100 inch, but may be more or less than that
dimension.
Thus, it can be seen that, when the electric toothbrush 10 is turned on by a
switch
(not shown) and the electric motor 16 drives the driving mechanism 18 and the
drive
shaft 26 to impart an oscillatory motion to the drive shaft 26, each of the
opposed bristle
head portions 40 and 42 will undergo an oscillatory movement as indicated by
the
double-headed arrow 32 in Figures 1 and 4B.
Referring again to Figures 1 through 3, the brush head portion 14 is seen to
further comprise a collar portion 52. The collar portion 52 includes the first
end 36 of
the brush head portion 14, and is adapted to be removably attachable to the
first end 20
of the power handle portion 12. Typically, that attachment is a slide or snap
fitment, and
is such as to protect the area where the drive shaft 26 is received in the
socket 106, or
such other plug and socket or blade and slot detachable connection as may be
employed.
However, it will be evident that the bristle head portion 42 and an
intermediate arm
portion 54 of the brush head portion 14 are freely moveable in an oscillatory
manner
about the longitudinal axis B of the brush head portion 14, within the collar
portion 52.
The opposed bristle head portions 40 and 42 are disposed at the end of the
intermediate
arm portion 54 which is opposite the first end 36 of the brush head portion
14. As noted,
the intermediate arm portion 54 is accommodated within the collar portion 52
in such a
manner as to be free for oscillatory motion relative to the collar portion 52,
about the
longitudinal axis B of the brush head portion 14.
Referring to Figure 1 through 3, the assembly of the brush head portion 14 is
described. It will be seen that the brush head portion 14 typically comprises
two matched
halves 56 and 58. Each of the matched halves 56 and 58 is, essentially, a
mirror image
of the other; and each comprises a respective one of the bristle head portions
40 and 42
and a respective half of the intermediate arm portion 54.
CA 02324816 2000-10-31
In the particular embodiment being illustrated and discussed, it will be seen
that
in each of the respective matched halves 56 and 58, a portion of the socket
106 is formed
at the first end 36, in each respective half of the intermediate arm portion
54.
Generally, the matched halves 56 and 58 of the brush head portion are
assembled
to each other by being sonically welded to each other. However, they may also
be easily
glued to each other. This is especially true when, as is typical, the material
from which
the two matched halves 56 and 58 of the brush head portion have been
manufactured is
ABS (acrylonitrile butadiene styrene). This factor becomes important when it
is
considered that a typical material from which the drive shaft 26 is
manufactured, is
nylon. The drive shaft 26 may also be formed of stainless steel. The drive pin
114, the
flywheel 112, and the cam block 116, may also be formed of nylon, stainless
steel, or
other suitable materials known to those skilled in the art.
It is evident that the manufacture of a double-headed toothbrush may be very
easily arranged. Specifically, the bristle head portions 40 and 42 may be
populated with
the bristle bundles, the ends of the bristle bundles trimmed and rounded, and
whatever
other manufacturing step is required for the bristles may be attended to,
without any
regard to the opposed bristle head. This is because the matching halves 56 and
58 are,
obviously, separately molded. Previously, double-headed toothbrushes such as
that
shown in Porper Design patent No. D259,977, were molded flat, and the bristle
head
portions were populated with bristle bundles, trimmed and end-rounded, but
with some
difficulty due to the close proximity of the other bristle head. Thereafter,
the respective
bristle head portions were required to be bent or post-formed using heat and,
thus, their
alignment and spatial relationship with each other is less exact than can be
accomplished
by the present invention where the matched halves 56 and 58 are manufactured
separately
and merely require to be assembled to each other, as described above.
Finally, referring to Figures 5 and 6, the advantage of the present invention
will
become obvious. In Figure 5, a typical molar 64 is shown together with its
supporting
16
CA 02324816 2000-10-31
gum structure 66. It is seen that the inner bristle bundles 72 on the
respective bristle head
portions 40 and 42 engage and will clean the occlusal surface of the tooth 64,
whereas
the remaining bristle bundles will engage and clean the buccal and lingual
surfaces of the
tooth 64. The oscillatory movement is, as noted above, only in the range of
3° to 10°, and
at a rate of 1,000 to 3,000 oscillations pr minute. Thus, the ends of the
bristle bundles
will be bent and will be constantly changing directions. They will, therefore,
probe
around the occlusal, buccal, and lingual surfaces of the tooth, and the probe
will be
effected with limited but effective chiselling action.
Indeed, it is believed that use of many typical prior art electric
toothbrushes,
particularly those which cause a sweeping motion either rotationally or
longitudinally,
particularly when combined with the use a typical abrasive dentifrice,
actually causes
thinning of the tooth enamel. Thus, the rapid but very short strokes of the
toothbrush of
the present invention are much less likely to cause enamel thinning or other
damage to
the teeth while, at the same time, providing a more efficient cleaning action
due to the
short stroke and the constantly changing direction of motion of the bristle
ends.
The same conditions are noted in Figure 6, where a typical front tooth 68 is
shown, having its buccal and lingual surfaces cleaned, as well as its occlusal
surface to
the extent that such surface exists.
It is evident that there is no necessity for there to be any great amount of
pressure
applied by the user in pressing the bristles of the bristle head portions
against the teeth.
Moreover, if more than sufficient pressure is applied, this may result in
slowing down
of the electric motor 16.
There has been described an electric toothbrush which exhibits obvious
advantages over prior art electric toothbrushes, and which particularly
provides an
apparatus which improves upon the highly promoted Bass Technique for brushing
the
teeth. The precise materials of the bristles and their manufacture are well
know to the
industry, as is the provision of a suitable power handle portion having an
appropriate
17
CA 02324816 2000-10-31
electric motor and linear reciprocating motion drive shaft. However, their
application
to an electric toothbrush in keeping with the present invention falls within
the scope of
the accompanying claims.
Other modifications and alterations may be used in the design and manufacture
of the apparatus of the present invention without departing from the spirit
and scope of
the accompanying claims.
Throughout this specification and the claims which follow, unless the context
requires otherwise, the word "comprise", and variations such as "comprises" or
"comprising", will be understood to imply the inclusion of a stated integer or
step or
group of integers or steps but not to the exclusion of any other integer or
step or group
of integers or steps.
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