Note: Descriptions are shown in the official language in which they were submitted.
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ELECTRIC TOOTHBRUSH
The present invention relates generally to electric
toothbrushes and more particularly to a toothbrush having a
power driven rotary brush in which the direction of
rotation of the brush is automatically controlled depending
on whether the top or the bottom teeth are being brushed in
order to brush any food debris present on the teeth and
gums in a direction away from the gums.
According to dentists, the proper way to brush
one's teeth is to press a tooth brush with the bristle side
resting on the gums and then moving the brush in a
direction away from gums and onto teeth. In this manner,
any food residue or debris that is present on the teeth and
gums will be moved away from the gums. If the brush
movement is reversed, i.e. in the direction from the teeth
to the gums, the food residue or debris will be forced into
the gap that exists between the gums and teeth, resulting
in the formation of unwanted plaque.
Most of the electric toothbrushes that are
presently in use have a bristle part which is reciprocated
through a short arc about the longitudinal axis of the
toothbrush. Such a reciprocating movement is quite
effective in cleaning some areas of the teeth, but the
reciprocating movement is not suitable for cleaning other
areas, such as the area near the gumline and the area of
the gums adjacent to the cheek. A rotary brush is
recognized as being a better cleaner than a reciprocating
brush, but the rotary brush also has a number of
disadvantages which detract from its suitability for use as
a toothbrush. For example, a rotary brush when rotated in
one direction only, has a tendency to drive food particles
and debris between the teeth the gumline when the brush is
rotating in a direction towards the gums.
Attempts have been made in the past to create a
motorized rotary toothbrush to control the direction of
SUBSTITUTE SHEET (RULE 26)
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rotation of the brush. However, all such devices utilize a
switc:~ing device that is operated by the users' fingers or
hands outside of the mouth.
For example, U.S. Patent No. 2,279,982 to Glynn
discloses a toothbrush in which the user has to put the
edge of guard (5) against the gums to control the rotation
of the brush in a direction away from gums to teeth. The
user controls the switching of the brush rotation by
pressing the guard (6) against the gums by turning the
handle which is located outside of the mouth. If the handle
is turned in the wrong direction by the user, until the
guard (6) touches any other object, such as the crown of a
tooth, the brush will brush in the wrong direction from the
tooth towards the gums. Moreover, since the guard (6) of
the Glynn toothbrush rests against the gums it is
inherently unstable due to the slippery nature of the gums.
No means is taught in Glynn for keeping the toothbrush
stable during the brushing of the teeth.
U.S. Patent No. 3,512,201 to Taylor discloses a
motorized toothbrush having a reciprocal and rotary motion
in which the direction of brush rotation is determined by
turning the cap of the brush with the thumb and index
finger outside of the mouth.
U.5. Patent No. 3,661,018 to Keefer et al.
discloses an electric toothbrush in which the direction of
brush rotation is determined by sliding a three-position
switch (47) mounted on the brush handle outside of the
mouth and is controlled by the user's finger.
U.5. Patent No. 3,829,922 to Koblansky discloses an
electric toc.~thbrush in which the switching of the direction
of brush rotation is activated by the movement of guard
(46) which is at all times spring-loaded to one position as
shown in Figures 3 and 6 of the patent. When the guard (46)
is at its normal resting position, the toothbrush of
Koblansky will always turn in one predetermined diLection.
Movement of guard (46) by touching a part of the mouth,
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such as the cheek or gums, causes the reversal of the brush
rotation. However, since the guard (46) is spring-loaded
such that without any outside forca it will always return
to its loaded, natural position, it is possible for the
= 5 brush of Koblansky to rotate in an undesired direction such
as away from the teeth and toward the gumline. Moreover,
there is no teaching in Koblansky for kseping the
toothbrush stable during the brushing of the teeth.
U.S. Patent No. 4,149,291 to Stoltz discloses a
toothbrush in which the direction of the brushing stroke is
controlled by a switch (9) that is mounted on the handle to
be finger operated by the user outside the mouth. To use
the Stoltz tootbrush properly the user would require
training and runs the risk of brushing in the wrong
direction.
U.S. Patent No. 4,225,994 to Stoltz discloses a
toothbrush wherein the direction of brushing is changed by
the movement of the handle section relative to the housing
of the toothbrush. To use the Stoltz brush properly, the
user requires training and runs the risk of brushing the
teeth in the wrong directions.
U.5 Patent No. 4,335,480 to Liu discloses a
toothbrush wherein in order to change the direction of
brushing, the user must manually activate switch (1B) which
is mounted on the handle outside of the mouth. To use the
Liu brush properly, the user requires training and runs the
risk of brushing the teeth in the wrong direction.
U.S. Patent No. 4,397,055 to Cuchiara discloses a
toothbrush wherein in order to change the direction of
brushii:g, the user must manually operate the electrical
switch (11) mounted on the exterior of the toothbrush
housing located outside of the mouth. To use the Cuchiara
brush properly, the user requires training and runs the
risk of brushing the teeth in the wrong direction.
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U.S. Patent No. 4,845,796 to Mosley discloses a
toothbrush wherein in order to control the direction of
brushing the user must manually control switches (32)
mounted on the handle outside of the mouth. To use the
Mosley toothbrush properly, the user requires training and
runs the risk of brushing in the wrong direction.
Therefore, there is a need for a motorized
toothbrush having a rotating brush in which the direction
of brush rotation. is controlled automatically depending on
whether the upper or lower teeth are being brushed.
The toothbrush of the present invention overcomes
the disadvantages of conventional motorized toothbrushes by
providing a power driven rotary brush in which the
direction of rotation of the brush is automatically
controlled depending on whether the top or the bottom teeth
are being brushed in order to brush any food debris present
on the teeth and gums in a direction away from the gums.
The toothbrush of the present invention utilizes a
direction controller that is placed inside the mouth
between the top and bottom teeth. The direction controller
controls the direction of brush rotation and serves to
stabilize the toothbrush relative to the teeth during the
brushing operation. The movement of the direction
controller operates a reversing switch to change the
direction of rotation of the rotary brush as required to
brush in a direction away from the gums and towards the
teeth. It is not necessary to remove the toothbrush from
the mouth in order to change the direction of rotation and
the cleaning action is substantially continuous once the
toothbrush has been inserted in the mouth.
The position of the direction controller relative
to the teeth is changed by movement of the toothbrush
within the mouth to brush the upper teeth or lower teeth.
The switching is "automatic" without the need of manually
operating a switch. The rotation of the brush may be
controlled by a bi-directional motor having a switching
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:mechanism to change the direction of rotation. Such a
switch is activated by the movement of the direction
controller. Alternatively, it is appreciated that a single
direction motor may be used to rotate the brush and a
5 gearing assembly having a reverse gear may be used to alter
direction of the rotation of the brush. The movement of the
direction controller can shift the gears directly to change
the direction of brush rotation.
During use of the toothbrush of the present
invention, the user puts the toothbrush into the user'.;
mouth with the direction controller placed between the
upper teeth and lower teeth. When the user pushes the
toothbrush upwards toward the roof of the mouth, keeping
the direction controller between teeth, the brush rotates
in the direction from the gums to the teeth. When the user
wants to brush the lower teeth, the brush is lowered toward
the lower teeth, keeping the direction controller between
the teeth. The rotation of the brush stops when the
direction controller is in a horizontal position between
upper and lower teeth. To brush the crown of teeth, the
controller can either be placed towards the cheek or placed
inside the mouth cavity.
FIG. 1 is a side perspective view of an electric
toothbrush in accordance with the present invention.
FIG. 2A is a schematic diagram illustrating the
electrical components, motor, and gear assembly for the
electric toothbrush of the present invention with the
direction controller in a horizontal neutral position and
the rotary brush in the resting position.
FIG. 2B is a scher:~atic diagram illustrating the
interaction between the direction controller and the
reversing switch of the electric toothbrush of the present
invention with the rotary brush shown in the operation
position for cleaning the upper teeth of a person.
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FIG. 2C is a schematic diagram illustrating the
interaction between the direction controller and the
reversing switch of the electric toothbrush of the present
invention with the rotary brush shown in the operation
position for cleaning the lower teeth of a person.
FIG. 3 is a sectional view taken along the line 3-3
of FIG. 1 of the rotary brush of the electric toothbrush of
the present invention showr_ in place next to the teeth of a
patient with the direction controller in the neutral
position and the rotary brush in the restins position.
FIG. 4 is a selectional view taken along the line
3-3 of FIG. 1 of the rotary brush of the electric
toothbrush of the present invention shown in use with the
teeth of a patient with the direction controller in the
operating position to clean the upper teeth of a patient
with the rotary brush rotating in the direction of arrow A.
FIG. 5 is a sectional view taken along the line 3-3
of FIG. 1 of the rotary brush of the electric toothbrush of
the present invention shown in use with the teeth of a
patient with the direction controller in the operating
position to clean the lower teeth of a patient with ~he
rotary brush rotating in the direction of arrow A.
The following description includes the best mode
presently contemplated for carrying out the invention. This
description is not to be taken in a limiting sense, but is
made merely for the purpose of describing the general
principles of the invention. The scope of the invention
should be determined with reference to the claims.
Referring to Fig. 1, there is shown an electric
toothbrush 10 consisting of nandle 12, stem 14, brush guard
16 and rotary brush 18. Handle 12 and stem 14 preferably
are formed into an integral unit made of durable molded
plastic. The electric toothbrush 10 may be sectioned into
half units and held together, after insert_on of internal
parts, by conventional snap fit locking arrangements and
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the like known in the art. Handle 12 contains a reversible
electrical motor 20 (see Fig. 2A) powered by electrical
energy source 22. The electrical energy source 22 may be a
replaceable or re-chargeable battery, however it must be
understood that it is within the contemplation of this
invention that the electrical energy source 22 may be a
rectified alternating current power source such as
conventional 120v, 60hz residential power. The power may be
brought to the electric tooth brush 10 by way of an
electrical cable connected to a conventional wall socket
and rectified using conventional circuitry known in the
art.
The electrical energy source 22 is electrically
coupled to motor 20 through reversing switch 24. To be
further described later, the reversing switch 24 may assume
three independent positions namely; a neutral switch
position as shown in Fig. 2A, where the motor 20 is
electrically decoupled from the electrical energy source
22; a first switch position as shown in Fig. 2B, where the
positive terminal (+) and the negative terminal (-) of
energy source 22 are electrically coupled to motor
terminals 26 and 28 respectively, to cause the motor 20 to
rotate in a first rotational direction; and a second switch
position as shown in Fig. 2C, where the positive terminal
(+) and the negative terminal (-) of electrical energy
source 22 are electrically coupled to motor terminals 28
and 26 respectively, to cause the motor 20 to rotate in a
second rotational direction opposite to the first
rotational direction.
As shown in schematic form in Fig 2A, a gear
assembly 32 transfers rotation and torque from the motor
shaft 30 to rotary brush drive shaft 34 (hereinafter shaft
34). Gear assembly 32 functions as a reducing gear and
comprises gears 36, 38, 40 and 42 in a straight tooth spur
gear arrangement. Gear 36 mounted on motor shaft 30 engages
gear 38 which in turn engages gear 40 which in turn engages
gear 42 that is mounted on shaft 34 by any one of
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conventional techniques. The diameter ratios of gesrs 36
and 38, and gears 42 and 90 are preferably in the range of
3:1, thereby providing an overall rotational speed
reduction from motor shaft 30 to shaft 34 of 9:1, with a
corresFonding increase in torque from motor shaft 30 to
shaft 34 of 9:1. In this manner high speed low torque
motors may be advantageously geared down to provide
adequate torque for proper low power operation of the
electric toothbrush 10. It is to be understood that other
gear ratios and gearing configurations may be suitable to
achieve low power high torque operation.
Ps noted in Fig. 1, rotary toothbrush 18, which is
located within brush guard 16, is mounted on shaft 34.
Brush 18 is generally cylindrically shaped and extends
between brush guard ends 44 and 46. The brush guard 16 is
partially open so as to partially surround the brush 18
thereby exposing sufficient brush surface for proper
engagement with teeth to be cleaned. The brush guard 16
serves tc prevent the brush 18 from contacting the inner
cheek of the mouth when the electric toothbrush 10 is
oriented in the mouth for cleaning teeth. Brush 18 may be
fixedly mounted on shaft 34, preferably by a dress fit or
by keying techniques known in the art.
Brush guard edge 46 also serves as an alignment
bearing surface having an annular bearing surface 48
through which shaft 34 extends so as to provide support for
brush 18 as it is urged against teeth to be cleaned. The
shaft 34 is journaled in the bearing surface 48 and thereby
maintains rotation of brush 18 about a fixed axis of
rotation defined by shaft 34.
A direction controller 50 is rotatably mounted over
shaft 34 between brush guard edge 46 and reversing switch
24. Direction controller 50 includes a hollow essentially
cylindrical portion 52 through which shaft 34 extends. The
distal end of direction controller 50 may be mounted on
guard edge 46 using any one of known techniques. For
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example, the inward facing surface of guard edge 46 may
include a protruding annular shoulder for seating a mating
annular recess in the distal end of the direction
controller 50 in a rotational slip fit arrangement. The
cylindrical portion 52 extends through stem 14 and is
mounted at its proximal end to reversing switch 24. The
direction controller 50 includes a ledge 54 which extends
in close proximity along the length of brush outer edge 56.
The ledge 54 is designed to fit between the upper and lower
teeth of a person and makes contact with the crowns 62, 66
of the teeth. The contact of the ledge 54 with the crowns
62, 66 cause the ledge 54 to be urged in a clockwise or
counterclockwise direction, respectively. In addition to
controlling the direction of the brush rotation, the ledge
54 functions to stabilize the brush 18 relative to the
teeth, as the ledge 54 is held in place between the crowns
62, 66 of the top and bottom teeth of the user. Switch 24
provides a slight resistance to movement such that ledge 54
remains fixed in position unless urged in either a
clockwise or counter clockwise rotation as the case may be.
With reference to Figs. 3, 4, and 5, movement of the
direction controller 50 may be appreciated. As shown in
Fig. 3, the ledge 54, while in the neutral position,
extends horizontally between the crowns 62 of upper teeth
58 and the crowns 66 of lower teeth 60. In such position
the reversing switch 24 electrically disconnects the motor
20 from the energy source 22. Accordingly, motor 20 is
deenergized and brush 18 does not rotate.
As shown in Fig. 4, the electric toothbrush 10 is
moved upward, relative to the neutral position, when it is
desired to brush upper teeth 58. In doing so, ledge 54
contacts the cro~:ns 62 of upper teeth 58 thereby urging the
ledge 54 in a counter clockwise rotation against the slight
resistance of switch 24 placing it in a first position (see
Fig. 2B), thereby energizing motor 20 so as to cause brush
18 to rotate in a counter clockwise direction. As shown in
Fig. 3, rotatior: of the brush 18 in a counter clockwise
direction causes contaminants to be brushed away from the
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gums 64, insuring that such contaminants are not brushed
under the gums 64 but rather away from the gums.
Similarly and as shown in Fig. 5, the electric
toothbrush 10 is moved downward, relative to the neutral
5 position, when it is desired to brush lower teeth 60. In
doing so ledge 54 contacts the crowns 66 of lower teeth 60
thereby urging the ledge 54 in a clockwise rotation to
place switch 24 in a second position (see Fig. 2C), thereby
causing motor 20 to be energized so as to cause brush 18 to
ZO rotate in a clockwise direction. In doing so contaminants
are brushed away from gums 68 insuring that such
contaminants are not brushed under gums 68. Although not
shown, it should be appreciated that when brushing teeth 58
and 60, brush guard 16 prevents brush 18 from contacting
the inner check portion of the mouth. Thus, the ledge 59
provides the necessary feed back to the electric toothbrush
10 to control the direction of rotation of the brush 18.
Turning now to Figs. 2A-C, the interaction between
the direction controller 50 and switch 24, to control the
direction of rotation of motor 10, may be understood. More
specifically, as shown in Fig. 2A, the ledge 54 is shown in
the neutral position. The direction controller cylindrical
portion 52 is coupled (shown in dotted lines) to a pair of
electrical contacts 70 and 72. In such position contacts 70
and 72 are restricted to making electrical contact with
contact pads 71 and 73 respectively, (contact pads 71 and
73 are coupled to energy source positive terminal (+) and
the negative terminal (-) respectively). In such position
an open circuit exists between energy source 22 and motor
20 and motor 20 remains de-energized.
As previously described when the electric
toothbrush 10 is moved upward to brush upper teeth 58, the
ledge 54 moves in a counter clockwise direction thereby
bringing electrical contacts 70 and 72 into electrical
contact pads 74 and 76 respectively. Accordingly, the
energy source positive terminal (+) is electrically coupled
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to motor terminal 26 through an electrical path that
includes contact pad 71, electrical contact 70 and contact
pad 74. Similarly the energy source negative terminal (-)
is electrically coupled to motor terminal 28 through an
electrical path that includes contact pad 73, electrical
contact 72 and contact pad 76. At this polarity setting
motor 20 rotates to cause brush 18 to rotate in a counter
clockwise direction.
Similarly when the electric toothbrush 10 is moved
downward to brush lower teeth 60, the ledge 54 moves in a
clockwise direction thereby bringing electrical contacts 70
and 72 into electrical contact with contact pads 78 and 80,
respectively. Accordingly, the energy source positive
terminal (+) is electrically coupled to motor terminal 28
through an electrical path that includes contact pad 71,
electrical contact 71 and contact pad 78. Similarly, the
energy source negative terminal (-) is electrically coupled
to motor terminal 26 through an electrical path that
includes contact pad 73, electrical contact 72 and contact
pad 80. At this polarity settig the motor 20 rotates to
cause the brush 18 to rotate in a clockwise direction.
Preferably, the electrical contacts and contact pads may be
constructed of or coated with a non-corrosive metal so as
to withstand arcing.
As an alternative to the embodiment of the electric
toothbrush described above, the reversing switch 24 may
comprise an external magnet that is linked to the direction
controller SO used to activate the motor 20. In this
alternative embodiment, the external magnet rides on the
surface of the handle 12 and two magnetic-reed switches are
placed inside the handle 12. The magnetic-reed switches are
oriented inside the handle 12 such that when the direction
controller 50 moves the external magnet to the proximity of
one magnetic-reed switch, the motor 20 turns in one
direction. When the direction controller 50 moves the
external magnet to the proximity of the other magnetic-reed
switch. the motor 20 turns in the other direction. When the
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external magnet is oriented between the two magnetic-reed
switches, none of the magnetic switches is activated and
the motor 20 stops. The use of an external magnet on the
surface of the handle 12 enhances the water-proofing of the
electric toothbrush 10 as the magnetic-reed switches may be
sealed within the handle 12.
It is appreciated that instead of utilizing a bi-
directional motor, the motor 50 may be unidirectional and
the direction of brush rotation may be altered by a gear
assembly having forward and reverse gears known in the art.
The engagement of the reverse gear of such a gear assembly
would be controlled by the position of the direction
controller 50. For example, the position of the direction
controller 50 can be used to shift the reverse and forward
gears of the gear train inside the handle to change the
brush's direction of rotation.
While the invention herein has been describe3 by
means of specific embodiments, numerous modifications and
variations could be made thereto by those skilled in the
art without departing from the scope of the invention set
forth in the claims.
