U.S. patent number 3,840,932 [Application Number 05/318,430] was granted by the patent office on 1974-10-15 for ultrasonic toothbrush applicator.
This patent grant is currently assigned to Ultrasonic Systems, Inc.. Invention is credited to Lewis Balamuth, Robert Meyer, Michael R. Rutten.
United States Patent |
3,840,932 |
Balamuth , et al. |
October 15, 1974 |
ULTRASONIC TOOTHBRUSH APPLICATOR
Abstract
An applicator in the form and/or a configuration adapted to be
ultrasonically vibrated to transmit mechanical vibrations from one
end thereof to bristle elements positioned at approximately the
other end thereof for use in the oral cavity.
Inventors: |
Balamuth; Lewis (Southampton,
NY), Rutten; Michael R. (East Islip, NY), Meyer;
Robert (Huntington Station, NY) |
Assignee: |
Ultrasonic Systems, Inc.
(Farmingdale, NY)
|
Family
ID: |
23238163 |
Appl.
No.: |
05/318,430 |
Filed: |
December 26, 1972 |
Current U.S.
Class: |
15/167.1; 15/195;
601/2; 15/22.1; 300/21 |
Current CPC
Class: |
A61C
17/34 (20130101) |
Current International
Class: |
A61C
17/16 (20060101); A61C 17/34 (20060101); A46b
009/04 (); A46b 013/02 () |
Field of
Search: |
;15/167R,22R,192,193,195
;300/21 ;128/62A |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Feldman; Peter
Claims
We claim:
1. A toothbrush adapted to be mounted on an automatic toothbrush
power handle having as a power source a source of vibratory energy
in the ultrasonic range, the said toothbrush comprising:
A. an elongated plastic brush portion adapted at one end to be
removably mounted on the power handle and of a length greater than
one wave length of a longitudinal elastic wave in the plastic brush
portion medium at the operating ultrasonic frequency of said
toothbrush;
B. a plastic brush head formed integrally with the elongated brush
portion at the opposite end thereof, said brush head being provided
with a series of apertures for respectively receiving an end of
each bristle cluster; and
C. a plurality of bristle clusters each including a plurality of
bristle elements, disposed on the brush head within said apertures,
said plastic brush head constituting a loaded longitudinal wave
transmission line, wherein the bristle clusters coincide with the
loaded parts of said loaded transmission line, and where such
loaded locations are essentially at loops of longitudinal
vibration.
2. A toothbrush as defined in claim 1, wherein the loaded
transmission line cross-section between bristle clusters, measured
along the longitudinal axis of said brush head is A.sub.o, and the
equivalent cross-section, taking account of the bristle clusters in
an adjacent loaded section of said line, is A.sub.1, larger than
A.sub.o, and the lengths of each section are selected equal to each
other and each length, 1.sub.1, is selected so as to satisfy the
equation:
tan (2 .pi.1.sub.o /.tau. ) = .sqroot.A.sub.o /A.sub.1 =
.alpha.
where .tau. is the wave length of a longitudinal elastic wave in
the toothbrush plastic medium at the said operating ultrasonic
frequency of said toothbrush.
3. A toothbrush as defined in claim 1, and furhter including means
for transmitting the vibratory energy from said brush head to said
bristle clusters within said apertures by substantially conforming
the respective wall of the apertures to the surface configuration
of the bristle elements comprising each cluster to form an adhesion
therebetween.
4. A toothbrush as defined in claim 1, further comprising means for
acoustically insulating the brush head of said toothbrush, wherein
the vibratory motion remains isolated therein and is not
transmitted to the oral cavity.
5. A toothbrush as defined in claim 1, wherein the means for
conforming the wall of the apertures to the surface of the bristle
elements is obtained by flowing the plastic of the brush head into
surrounding relation to the bristle elements.
6. A toothbrush as defined in claim 1, wherein said means for
removably coupling said elongated brush portion to the power handle
includes securing means including a threadably engageable portion
adapted to mate with a complementary threadably engageable portion
of the power handle.
7. A toothbrush as defined in claim 1, and further including means
for mechanically securing said bristle clusters to said brush
head.
8. A toothbrush adapted to be mounted on an automatic toothbrush
power handle having as a power source a source of vibratory energy
in the ultrasonic range, the said toothbrush comprising:
A. an elongated plastic brush portion adapted at one end to be
removeably mounted on the power handle;
B. a plastic brush head formed integrally with the elongated brush
portion at the opposite end thereof, said brush head being provided
with a series of apertures for respectively receiving an end of
each bristle cluster;
C. a plurality of bristle clusters each including a plurality of
bristle elements, disposed on the brush head within said
apertures;
D. means for mechanically securing said bristle clusters to said
brush head, and
E. means for transmitting the vibratory energy from said brush head
to said bristle clusters within said apertures by substantially
conforming the respective wall of the apertures to the surface
configuration of the bristle elements comprising each cluster to
form an adhesion therebetween.
9. A toothbrush as defined in claim 8, wherein the bristle clusters
are all of the same length.
10. A toothbrush as defined in claim 8, wherein the bristle
clusters are arranged in rows on the brush head.
11. A toothbrush as defined in claim 8, wherein the means for
mechanically securing each said bristle cluster includes a
staple.
12. A toothbrush as defined in claim 8, wherein said elongated
plastic brush portion has a length greater than one wave length of
a longitudinal elastic wave in the plastic brush medium at the
operating ultrasonic frequency of said toothbrush.
13. A toothbrush as defined in claim 8, wherein said plastic brush
head constitutes a loaded longitudinal waver transmission line,
whereby the bristle clusters coincide with the loaded parts of said
loaded transmission line, and where such loaded locations are
essentially at loops of longitudinal vibration.
14. A toothbrush as defined in claim 13, wherein the loaded
transmission line cross section between bristle clusters, measured
along the longitudinal axis of said brush head is A.sub.o, and the
equivalent cross-section, taking account of the bristle clusters in
an adjacent loaded section of said line, is A.sub.1, larger than
A.sub.o, and the lengths of each section are selected equal to each
other and each length, 1.sub.o, is selected so as to satisfy the
equation:
tan ( 2 .pi.1.sub.o /.tau. ) = .sqroot.A.sub.o /A.sub.1 =
.alpha.
where .tau. is the wave length of a longitudinal elastic wave in
the toothbrush plastic medium at the said operating ultrasonic
frequency of said toothbrush.
15. A toothbrush as defined in claim 8, wherein said bristles are
crimped.
16. A toothbrush as defined in claim 8, wherein each said bristle
cluster is mounted at substantially a loop of longitudinal motion
along the axis of said brush head.
17. A toothbrush as defined in claim 8, wherein the means for
conforming the wall of the apertures to the surface of the bristle
elements is obtained by flowing the plastic of the brush head into
surrounding relation to the bristle elements.
18. A toothbrush as defined in claim 8, wherein said bristle
clusters are of a plastic material.
19. A toothbrush as defined in claim 8, further comprising means
for acoustically insulating the brush head of said toothbrush,
wherein the vibratory motion remains isolated therein and is not
transmitted to the oral cavity.
20. A toothbrush as defined in claim 19, wherein said means for
acoustically insulating the brush head of said toothbrush comprises
a layer of vibration absorbent material which substantially covers
the entire brush head.
21. A toothbrush as defined in claim 8, wherein said bristle
clusters are disposed with respect to the direction of vibration in
said brush head so that flexural vibrations are induced in said
bristle clusters.
22. A toothbrush as defined in claim 21, wherein said bristle
clusters are disposed in a plane substantially perpendicular to the
direction of vibration.
23. A toothbrush as defined in claim 8, wherein said bristle
clusters are comprised of a plurality of bristle elements.
24. A readily replaceable brush as in claim 23, wherein the bristle
elements of the bristle cluster are of various lengths.
25. A toothbrush as defined in claim 23, wherein at the frequency
of vibration the bristle elements are of a length and diameter to
vibrate at a level sufficient to cavitate a fluid film on the tooth
surfaces.
26. A toothbrush as defined in claim 23,
a. wherein said bristle elements extending from said brush head are
of a length in the range of from substantially 0.30 inch to 0.60
inch; and
b. wherein said bristle elements are of a diameter in the range of
substantially from 0.004 inch to 0.020 inch.
27. A toothbrush as defined in claim 8, wherein said means for
removeably coupling said elongated brush portion to the power
handle includes securing means including a threadably engageable
portion adapted to mate with a complementary threadably engageable
portion of the power handle.
28. A toothbrush as defined in claim 8, wherein the free end of the
bristle elements are each rounded.
29. A toothbrush as defined in claim 8,
a. wherein said bristle elements are of a diameter in the range of
0.004 inch to 0.020 inch,
b. wherein a bristle cluster includes approximately eighty ends, at
the nominal bristle element diameter of 0.008, and
c. wherein each aperture is approximately 0.093 inch diameter and a
depth of approximately 0.120 inch.
30. A toothbrush adapted to be mounted on an automatic toothbrush
power handle having as a power source a source of vibratory energy
in the ultrasonic range, the said toothbrush comprising:
A. an elongated plastic brush portion adapted at one end to be
removeably mounted on the power handle and capable of supporting
ultrasonic vibrations and adapted to be vibrated at said
frequencies;
B. a plastic brush head formed integrally with the elongated brush
portion at the opposite end thereof and capable of supporting
ultrasonic vibrations, said brush head being provided with a series
of apertures for respectively receiving an end of each bristle
cluster;
C. a plurality of bristle clusters each comprised of plastic
bristle elements and disposed on the brush head within said
apertures;
D. means including a staple for mechanically securing said bristle
clusters to said brush head; and
E. means for transmitting the vibratory energy from said brush head
to said bristle clusters within said apertures, wherein the means
for transmitting the vibratory energy waves from said brush head to
said bristle clusters includes substantially conforming the
respective wall of the apertures to the surface configuration of
the bristle elements to form an adhesion therebetween,
F. said means for mounting said elongated brush portion to the
power handle including securing means having a threadably
engageable portion adapted to mate with a complementary threadably
engageable portion of the power handle.
31. A toothbrush as defined in claim 30, further comprising means
for acoustically insulating the brush head of said toothbrush
whereby the vibratory motion remains isolated therein and is not
transmitted to the oral cavity.
32. A toothbrush as defined in claim 31, wherein said means for
acoustically insulating the brush head of said toothbrush comprises
a layer of vibration absorbent material which substantially covers
the entire brush head.
33. A toothbrush as defined in claim 31, wherein at the frequency
of vibration the bristle elements are of a length and diameter
calculated to vibrate at a level sufficient to cavitate a fluid
film on the tooth surfaces.
34. A toothbrush as defined in claim 31,
a. wherein said bristle elements extending from said base are of a
length in the range of from substantially 0.30 inch to 0.60 inch;
and
b. wherein said bristle elements are of a diameter in the range of
substantially from 0.004 inch to 0.020 inch.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
In a co-pending patent application of Lewis Balamuth, Arthur Kuris,
and Manual Karatjas, Ser. No. 318,428, filed Dec. 26, 1972, for
Ultrasonic Motor-Converter Systems, and assigned to the assignee of
the present invention, an ultrasonic system that may be used as for
oral cleaning is shown having a brush applicator that may be
designed in accordance with the present invention.
BACKGROUND OF THE INVENTION
This invention relates to the dental field and more particularly to
a toothbrush designed for and compatible with an automatic
toothbrushing system which is powered in the sonic and ultrasonic
range for inducing vibrations therein.
The applicants have found that for commercial application of their
invention it would be desirable for home use to utilize a brush
head made substantially of plastic and not of a metallic material
as disclosed in U.S. Pat. No. 3,335,443. In order to achieve the
assembly of brushes having a plastic body on a mass production
basis, they required certain novel procedures and designs in order
to obtain these results.
OBJECTS OF THE INVENTION
One object of the invention is to provide a novel applicator to be
used in the ultrasonic energy range.
Accordingly, another object of this invention is to provide a
toothbrush especially designed for use with a sonic-ultrasonic
powered system in order that improved cleaning and polishing may be
achieved at the same time gingival health benefits are
obtained.
Another object of the invention is to provide a toothbrush head
designed for compatible use from an ultrasonic power source.
Another object of the present invention is the provision of a brush
head in which plastic tip bristles and plastic head brushes are
coupled together for the transmission of ultrasonic and sonic
energy for the individual bristle elements.
Other objects of the invention will become apparent as the
disclosure proceeds.
SUMMARY OF THE INVENTION
The present invention provides for an interchangeable toothbrush
assembly that when coupled to an ultrasonic motor is adapted to be
vibrated at an ultrasonic rate and simultaneously therewith at a
sonic rate while the motor may be hand held and the bristle
clusters of the brush are utilized for the removal of foreign
deposits from teeth. In order to assure the proper transmission of
high frequency energy from the body portion of the brush to the
individual bristles, appropriate securing means are employed such
that the relation of the plastic bristles to the plastic body
portion are properly matched and energy is transmitted.
As hereinafter discussed, there is a defined relationship between
the spacing of the bristle clusters and the selection of the
material from which the body portion of the brush is fabricated so
as to assure a proper vibratory energy transmission. The applicator
means or brushes of the present invention may have individual
bristle diameters and a resistance factor to obtain maximum
cleaning efficiency. For example, it has been found that a brush
having bristle clusters that range in the diameter of 0.004 inch to
0.020 inch and having approximately 80 bristles per cluster at
0.008 diameter generally form a bristle configuration to which the
energy may be properly transmitted and yet also properly clean.
Another aspect of the invention resides in the fact that the output
end of the bristle clusters may be contoured so as to accept the
configuration of the teeth as same is positioned within the oral
cavity for use by the user such that the brush may be placed, if
desired, in relatively fixed position against the teeth so as to
maintain it in a relatively fixed position as the energy from the
bristle tufts is transmitted to obtain the cleaning results.
BRIEF DESCRIPTION OF THE DRAWINGS
Although the characteristic features of this invention will be
particularly pointed out in the claims, the invention itself, and
the manner in which it may be made and used, may be better
understood by referring to the following description taken in
connection with the accompanying drawings forming a part hereof,
wherein like reference numerals refer to like parts throughout the
several views and in which:
FIGS. 1-5 are diagrammatic views of applicators to help illustrate
the theory of the present invention;
FIG. 6 is a diagrammatic view of applicator means in which the
bristles are curled;
FIG. 7 is a diagrammatic view to help illustrate the present
invention;
FIG. 8 is a diagrammatic view to help illustrate the theory of the
present invention;
FIG. 9 is a perspective view of an ultrasonic home oral unit in
accordance with the present invention;
FIG. 10 is an enlarged sectional view illustrating applicator means
in accordance with the present invention;
FIG. 11 is an end view of the applicator means illustrated in FIG.
10;
FIG. 12 is a fragmentary elevational view of a portion of the
applicator means in accordance with the present invention;
FIG. 13 is an enlarged fragmentary sectional view taken
substantially along the line 13--13 in FIG. 12;
FIG. 14 is an enlarged fragmentary sectional view taken
substantially along the line 14--14 in FIG. 12;
FIG. 15 is an enlarged fragmentary sectional view illustrating the
individual bristles secured in position;
FIG. 16 is an enlarged fragmentary view illustrating the rounded
bristle ends;
FIG. 17 is a front view of another form of applicator means in
accordance with the present invention;
FIG. 18 is a bottom view of the applicator means in FIG. 17;
FIG. 19 is a top view of the applicator means in FIG. 17;
FIG. 20 is an enlarged side view in cross-section of the applicator
means of FIG. 17;
FIGS. 21 and 22 are enlarged diagrammatic views of bristle
elements;
FIGS. 23-26 illustrate the cleaning system of the present invention
in relation to a set of human teeth and are helpful in explaining
the process of the instant invention; and
FIG. 27 is a block diagram illustrating the method of manufacturing
the brush of the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS
The ultrasonic applicator means of the present invention, as
hereinafter discussed with respect to FIGS. 1-6, is dependent upon
an interrelated number of characteristics in order to function in a
desired manner.
Prior art disclosure of ultrasonic toothbrush design requires that
the ultrasonic activity of each bristle cluster pair diminishes
proportionately to their position or distance from said bristle
holding toothbrush section or element. Thus, it was desirable to
make the applicator means operate at the lowest possible ultrasonic
frequency so that the wave length of waves in the body section
would be as long as possible, thereby diminishing the effect of
displacement from the free end. It was recognized that this
frequency limitation seriously hampered the freedom to design the
most effective brush head for optimal cleaning and other effects
inherent in the use of ultrasonic energy for the care of teeth and
gingiva.
As FIG. 1 shows diagrammatically in accordance with the prior art
for a toothbrush 10a having a body section 12a of a metallic
material which forms the bristle cluster base which shows the
greater ratio of the cluster base, 1, to the loop-node (.tau./4)
distance, the more will the amplitude of vibration of the bristle
cluster base 12a diminish from its free maximum vibration end 14a
as illustrated by the curve 16a which represents the amplitude of
vibration from the node at the vertical plane at 18a in at which
there is no longitudinal vibration to a loop of longitudinal
vibration where the amplitude of vibration is maximum as indicated
at the vertical plane 22a.
Now, the physical demands of toothbrush dynamics require a number
of bristle clusters 15a each having a bristle base 20a and elements
21a of finite size (each cluster might have a base diameter of
about 3/32 inch). Furthermore, these demands mean that to achieve
ordinary toothbrush capacity, one must provide a length of
vibratory base material which is at least of the order of a half
inch up to one inch in magnitude. Now applicants recognized that
conventional electric toothbrushes operating in the 60 vibrations
per second range do not encounter the above problem because the
"wave length," so to speak, becomes relatively infinite or at least
so large that all the bristle clusters bases move in phase with the
same reciprocating stroke.
Now, in order to enjoy the unique advantages and easy adaptability
of the ordinary tooth form, applicants have discovered a way of
desinging a toothbrush to satisfy these requirements. The essence
of applicants' invention resides in the discovery that there are
acoustically efficient plastic materials with extremely low speeds
of sound (or what is the same thing, low speeds of longitudinal
vibrations). For example, a polycarbonate such as Lexan, has a
speed of longitudinal waves in a rod of about one fourth the value
of the speed of such waves in steel or aluminum at the same high
frequency (i.e., above 20 KHz). This results from the fact of the
extremely low value of the Young's Modulus of this plastic.
Applicants have further discovered that it is possible to "load"
the plastic rod with a dispersion of powder or other types of dense
filler whereby its density may materially increase without a
corresponding increase in Young's Modulus. This still further
lowers the speed of longitudinal waves in such an element.
As a result, an analysis is provided in FIGS. 2A in which a steel
rod, or body section 12b is illustrated as vibrated, at 40 KHz and
compare it with a Lexan rod in FIG. 2B or body section 12c at the
same frequency. Steel has a wave length of about 5 inches at 40 KHz
and therefore a .tau./4 of 1.25 inches.
The Lexan corresponding .tau./4 will be approximately one fourth of
the value for steel 1/4.times. 1.25 inches = 0.36 inch.
FIGS. 2A and 2B shows the difference of vibration as indicated by
curve 16b for steel in distribution at 40 KHz for a steel rod with
bristles and a Lexan rod as indicated by curve 16c with bristles.
As will be seen later, the presence of the bristle clusters
modifies the curves 16a (same as 16b) and 16c in opposite senses,
whereby optimal distribution of ultrasonic power density in the
bristle clusters is favored in the case of curve 16c and is
worsened in the case of curve 16a. Clearly the steel rod body
section 12b shows a significant reduction in amplitude of the bases
20b of the bristle clusters 15b in going from point B to point A
over an approximately 3/4 inch distance. The Lexan body section 12c
on the other hand shows a distribution of nodes and loops of
vibration as illustrated by curve 16c within the same approximately
3/4 inch section at the same frequency. As a result, it is possible
to distribute the bristle clusters so as to take advantage of such
sites as a, b, c and d (see FIG. 2B). In fact, it is evident that
by simple design it is possible to obtain an extended toothbrush
complement of bristle clusters 15c so that the vibration amplitude
(and hence the efficiency of action) of all clusters may be
monitored at about the same level.
This is a novel concept to this art and enables one to produce
efficient, inexpensive toothbrushes operating in the ultrasonic
frequency range. In addition, new design possibilities arise in
relation to the transmission line design, which did not exist
before, because the distance between bristle clusters is of the
same order as the .tau./4 of the transmission line. It is intended
to take advantage of all such possibilities within the scope of
this invention. For example, consider a structure such as FIG. 3,
which accomplishes the results desired by the use of a body section
12d having enlarged radial sections 24d with bristle clusters 15d
extending radially therefrom.
FIG. 4 illustrates the invention in which bristle clusters 15e may
be in radial arrays from the body section 12e in such a manner that
a multiple number of clusters exist in each plane of the brush
10e.
Now, applicants have discovered, that in order to be able to
produce a home oral device together with its necessary electronic
converter, the most basic questions to be answered were those
permitting increased efficiency of operation, adequate safety in
home use in the mouth, and especially simplicity of design
permitting low production costs for a mass-production product. One
important part of this effort in the case of the applicator means
or brush head was to guarantee good vibration energy transfer from
the base to the bristle clusters without having recourse as in the
prior art to relatively expensive epoxy bonding of such cluster in
a metal base. Also, the effect shown in FIG. 3, and hereinafter
discussed in greater detail, was to be made as simply as possible
so as to achieve optimum spacing of bristle clusters relative to
the standing wave pattern set up in the base during operation. This
was done by a combination of factors whereby every element in the
design entered into experimental work. For example, bristle
diameters were selected which would produce a visible fog-like
spray of water from the wet bristle head when vibrating in the
motor-converter system of the invention. Also, a maximum number of
bristles per cluster was used compatible with the cross-sectional
dimensions of the base portion. In addition, specific advantage was
taken in inserting a bristle cluster by employing a well known mass
production technique which caused a bristle cluster to be composed
of a bundle of U-shaped plastic filaments, which are pushed into an
aperture with the aid of a metal staple which stays with the
bristle cluster after insertion. This mechanical technique is
extremely fast and is preferably carried out with the thermoplastic
base in a heated condition just below its creep temperature, so as
to minimize static residual stresses due to the insertion. But,
such mechanical insertion still leaves voids in the region of
insertion which serve to lessen the transmitting efficiency of the
bristles to the base insofar as vibration transmission is
concerned. This difficulty was obviated by the simple expedient of
dipping the brush head, after being formed, into a solution which
acts as a better solvent for the thermoplastic base material than
for the thermoplastic bristle material. For example, a preferred
embodiment of the head would include Nylon bristles staple-mounted
into a Lexan (polycarbonate plastic) base and blended with a
solution of methylene chloride. The solvent can be applied either
by a brief dip after mechanical fabrication or can be incorporated
into the staple mounting operation by addition of a small amount of
said solvent at that time.
In any case, the results achieved are typically hereinafter
illustrated with respect to FIGS. 9-22, which shows the U-shaped
bristle elements, in place with the cross-section of the metal
staple showing. In addition, the spaces between the bristles are
filled with the base material which has flowed into place due to
the action of the added solvent, which is volatile and vanishes
after performing its job. Thus a number of effects are
simultaneously achieved whereby excellent acoustic or high
frequency vibration coupling is achieved with minimal losses. For
example, in practice, it has been found that, with an eight bristle
cluster applicator head is mechanically coupled onto the motor
output, a definitely visible spray from the bristles in a water
wetted condition may be produced on the 30KHz range with input of
only 2 watts into the motor. This recital of facts alone will
illustrate to anyone skilled in the art that the instant type of
brush head and body is extraordinarily efficient.
In addition, the construction of FIG. 5 serves to bring about in
part the condition shown in FIG. 3, without the alterations r.sub.o
and r.sub.1 of cross-section shown in FIG. 3. This is because the
bristle clusters as shown, for example, at b in FIG. 6 together
with the metal staple, act as an increased mass in the section of
the transmission line where it is inserted.
In order to understand this matter and its importance, we will
consider in FIG. 5 a quarter wave transmission line for
longitudinal or torsional vibrations as composed of two sections
26f and 28f of equal length. The line is shown as cylindrical for
mathematical convenience, which in no way affects the force of the
following argument. Now, the radii r.sub.o and r.sub.1 and the
length 1.sub.o, and the length 1.sub.o are easily shown to be
connected in the following equation
tan (2.pi.1.sub.o /.tau.) = (r.sub.o /r.sub.1) = .alpha.
In the case of a non-cylindrical line, then we may use the
cross-sectional areas A.sub.o and A.sub.1, and in this case
.alpha.= A.sub.o /A.sub.1, in the above equation. From the equation
a simple table of values may be made as follows:
Table I ______________________________________ (2.pi.L.sub.o
/.tau.) .alpha. Degrees ______________________________________ .32
17.8.degree. .45 24.3.degree. .63 32.3.degree. .77 37.6.degree. .89
41.6.degree. 1.00 45.0.degree.
______________________________________
As may be seen from the equation and the table, when r.sub.o is
about one third of r.sub.1, then the value of 2.pi.1.sub.o /.tau.
is 17.8.degree. as compared with 45.degree. when the two
cross-sections are equal. This is equivalent to the conclusion that
the .pi./2 phase shift shown in FIG. 5 takes place in a distance
which is (17.8/45) = 0.4 of the distance required for uniform
cross-section. Thus, in the previous example given in connection
with FIG. 2, at 40 KHz, the value of .tau./4 was shown to be 0.36
inch in Lexan. With the alternating reduced cross sections of the
FIG. 5 presentation, the equivalent .tau./4 or .pi./2 shift in
phase would occur in a distance of 0.4 .times. 0.36 = 0.144 inch.
The bristle clusters would still further reduce this phase shift
distance. Thus, it is shown that the novel design features
disclosed herein do in fact allow bristle cluster locations at
region of uniformly high activity.
In order to understand better the relation between frequency of
operation of the disclosed home oral device and the various
dimensions of the bristle cluster arrangement and the total
toothbrush head herein described for rigid detachable fastening to
the ultrasonic motor, we will take a few examples. Let us consider
operation first at 30KHz. With a polycarbonate (Lexan)
thermoplastic head, we have the wave length, .tau., equals 1.86
inches, and so a quarter wavelength corresponds to 0.46 inches.
Now, as has been taught herein through FIG. 5 and Table I, the
presence of the metal staple elements, together with the bristle
clusters, produces an .alpha. value substantially less than one.
This means that the spacing of bristle clusters relative to the
phase of the standing longitudinal waves in the brush head is
substantially reduced to a value determined by the numerical value
of .alpha.. For example, with two bristle clusters, b, as shown in
FIG. 6, the .alpha.-effect is magnified and it is readily possible
to reduce the 90.degree. phase shift distance, d, by at least 50
percent, which in our 30KHz example becomes equal to 0.23 inch, or
about a quarter of an inch. The distance, d, may be still further
controlled and decreased by varying the cross-section of the
thermoplastic toothbrush bases 12g and 12h as shown in FIGS. 6 and
7 respectively.
For a frequency of 40KHz, .tau. equals 1.4 inches and a quarter
wavelength corresponds to 0.35 inch. In this case, distance, d,
between the bristle clusters 15g and 15h as described in relation
to FIGS. 6 and 7 would be about 0.18 in or about 3/16 of an
inch.
If the base were metal, such as aluminum or stainless steel then at
30KHz, .tau.= 6.67 inches, .tau./4 = 1.6 inch. But when we consider
the distance, d, the .alpha.-effect (not considered in the prior
patents) would be reversed, because the acoustic impedance of the
metal is so much greater than that of the bristle cluster and its
epoxy base. In this case, the holes in the metal are filled with a
lighter, lower mechanical impedance element and the distance, d, is
substantially .tau./4 or greater, or at 30KHz, equal to or greater
than 1.6 inch. Now, it is evident that this is greater than the
whole length of a brush head normally used for toothbrushing and so
the novel art disclosed in the instant invention may not be
practiced in the prior art disclosed toothbrushes.
The correspondence between FIGS. 6 and 7 and the design structure
of a toothbrush in the present invention may be clearly seen in
FIGS. 10-17, inclusive, FIG. 6 illustrating bristle elements 21g
having a curled like configuration.
As can be seen in FIG. 8, the design has been accomplished whereby
the toothbrush 10j has bristle clusters 15j in regions on the base
12j, P, along the verticle plane defined by line 22j are in regions
of peak amplitude of vibration as in the curve 16j due to the
transmission line effects discussed above. In particular radial
sections 24j are in effect the equivalent of the combined mass at
the base or the bristle clusters 15j. It will be noted that, in
order to conform with the theory, it is desirable to place the
bristle clusters 15 j at the very end of the toothbrush base 12j so
that the portion 30j is shorter in length than the portion, 24j as
shown. Also the distance D is equal to a half wavelength in the
thermoplastic toothbrush transmission member, needed to screw on
the brush to the motor. Accordingly, d' is a quarter wave, which in
turn as we have shown is larger than the distance, d, which in its
turn depends on the value of .alpha. which may be chosen in the
various ways disclosed. For Lexan at 30KHz, a half-wave length, D,
is about 0.93 inch. Therefore, in making a usable toothbrush
according to the teaching of this invention, the size and depth of
the mouth (oral cavity) must be at least three inches, and so must
incorporate a number of half-wavelengths (180.degree. phase shift)
or a number of 90.degree. phase shifts in the node to loop
distribution in going from the attachment point to the end of the
brush head. A typical Lexan head with nylon bristles operating at
about 30KHz would include 11 or 12 90.degree. phase shift elements
in the 3-inch length of the disclosed detachable toothbrush. A
toothbrush head having a metallic base is designed and is therein
taught as a fraction of a 90.degree. phase shift.
Thus, applicants believe they have shown the sophisticated design
features of the disclosed invention herein, and have adequately
related it to the prior art. To summarize, applicants have found
the sophisticated approach herein described with the whole
interrelated combination of production and design features to be
essential to the creation of an ultrasonic toothbrush which can be
mass-produced with associated motor-converters within a cost basis
making possible for the first time to have an effective toothbrush
at consumer prices. This is the essential step to making oral
hygiene control in the home possible, with benefits inherent in the
ultrasonic approach and which benefits cannot be otherwise
created.
PREFERRED EMBODIMENTS
FIG. 9 illustrates the ultrasonic system 40 which includes
instrument means 42 in combination with converter means 44 that
work in unison to perform a variety of applications as for example
that of tooth brushing. The ultrasonic system 40, for example, is
designed to permit the daily use by a person in the home of a
toothbrush, whose bristles are mechanically vibrated in a dual
frequency in that there is introduced a very low level of high
frequency mechanical vibration and, the total power level
introduced into the bristles being considerably less than one
watt.
In addition to the functions performed by an ordinary nonelectric
traditional toothbrush, the ultrasonic system 40 provides a local
action, due to the invisible very low speed microscopic excursions
of the individual bristles 45. These low speed invisible reciprocal
motions, in combination with saliva or saliva assisted with a
suitable dentifrice, provide beneficial stimulation of the gingiva,
especially at the tooth-gingiva junction regions, as well as a
removal of plaque, which is generally recognized as a principal
source of calculus formation and possibly subsequent loss of teeth
due to periodental disease.
Thus, to recapitualte, the purpose of the ultrasonic system 40 when
used with bristle elements is to provide a person with a device to
use in the home and thereby assist the dentist in achieving a
significant care of the teeth and gums, in order to help prevent
the onset of periodental disease.
The instrument means 42 includes handle means 46 adapted to be held
by the user in a conventional manner, and also having the
detachable applicator means or assembly 10 containing the bristle
clusters or stimulants 15 to be ultrasonically vibrated. Extending
from one end of the instrument means 40 thereof is supply means 48
which supplies to the instrument means 42, power from the generator
or power means 44 which may have an electrical cord 49 connected to
a plug 50 adapted to be plugged into a standard electrical outlet;
i.e., 60 cycles per second. Switching means 52 of the generator 44
includes a switch 54 for providing power for energizing the
ultrasonic transducer or motor contained within the instrument
casing or housing means 46 of the hand held instrument means 42.
The energy from the generator 44 is transmitted to the ultrasonic
motor by wires extending through the flexible conduit 56 of the
power supply means 44. There exists a multi-frequency form of
vibrations at the bristle clusters 15 and in the high frequency
range illustrated by the double headed arrow 60 which forms a
synergistic cooperation of a number of special properties inherent
in the total system.
The complete assembly for use in the home includes the generating
means 44, for example, a transistorized oscillator capable of
producing electrical oscillation at a frequency in the ultrasonic
range, as defined herein and the sonic range as defined herein. In
practice, the generator 44 may be as small from 1 to 4 watts and
generally in the range of 1 to 10 watts, and is preferably of the
solid state type. It is desired to employ an oscillation generator,
which automatically adjusts to the resonant frequency by reason of
the changes occurring in the latter as the applicator member 10 is
driven and engages the teeth and gums of the human being cleaned.
Such changes in the resonant frequency of the mechanically
vibrating unit occur by reason of the fact that the natural
frequency of the applicator head 10 will vary with the load placed
upon it which might be water, saliva, dentifrice, etc.
The electrical assembly 44 automatically activates the ultrasonic
motor 45 in the handpiece housing 46, which in turn transmits
modulated high frequency ultrasonic vibrations to the bristle
clusters 15 at the end of the applicator means in the form of a
plastic transmission line connected detachably to the ultrasonic
motor input. The modulation of the high frequency vibrations is,
for example, a 60 cycle component which is supplied through the
electric converter assembly 44 directly to the bristle clusters 15.
The low rate of vibration may be in the range of 10 cycles to 1,000
cycles per second.
By way of example for home consumer application in a tooth brush,
the power drawn by the electric converter assembly 44 may be in the
range of 1 to 10 watts. The power delivered to the ultrasonic
reciprocal motor 45 in the handpiece is under two watts. The
mechanical power delivered to the bristles and subsequently into
the gingiva and teeth of the user is variable depending upon the
pressure and movement of the bristles by the hand of the user. But,
in any case, this power under maximum conditions is but a minute
fraction of the power delivered to the handpiece is consumed in
overcoming electrical and mechanical dissipation of the motor
reciprocal motion and toothbrush element.
Essentially, the motor construction, as hereinafter described, is
designed depending upon the use thereof to accept a variety of
applicator means 10 and the magnitude of ultrasonic mechanical
vibrations to be imparted thereto may be selected by proper motor
design. The motor includes a transmission member which has a rear
section within the housing 46 and a front section 62 extending
beyond the casing 46.
The ultrasonic motor in conjunction with the applicator means 10 is
longitudinally dimensioned so as to have lengths which are
generally whole multiples of half-wavelengths of the compressional
waves established therein at the frequency of the combines
longitudinal length of the components so that longitudinal loops or
other components of motion occur at the end of the applicator means
10. Thus, the optimum amplitude of longitudinal vibration and
hyperaccelerations of transmission is achieved, and such amplitude
is determined by the relationship of the motor and applicator means
10.
Now referring more particularly to FIGS. 10-13, there is
illustrated the applicator means 10 which is designed to be used
with the ultrasonic instrument means 40 as previously illustrated
with respect to FIG. 9. The applicator means 10 includes a base or
body section means 12 with a longitudinally spaced apart ends 63
and 64 and having a brush head or head portion 65 which is the
upper section in which the bristle clusters 15 are contained and a
spaced lower portion or end 66 with a middle section or portion 68
extending therebetween. The body portion 12 which is preferrably
made out of a thermo-plastic material such as Lexan has associated
therewith securing means 70 at the lower portion 66 in the form of
a securing member 72 inserted at one end thereof having a mating
portion 74 in the form of threads which is adapted to mate with a
complimentary threaded portion 76 of the lower portion 66. To be
maintained firmly in place, a bonding material or cement 77 is used
to secure and maintain intimate coupling between the threaded
portion 74 and the surrounding lower portion 66.
The securing member 72 includes a gripping section 78 which is
shown to be of a hexogonal shape so as to be readily grasped
between fingers of the user or a wrench for obtaining the
disengagement of the applicator means 10 from the oral device. A
stud 80 extends from the opposite end of the gripping section 78
and has a thread that may be of a quick type in that it is not a
fine thread so that a minimal number of turns of the applicator
means 10 is required before the bottom edge 82 abuts the
complimentary surface of the instrument means. A sleeve 88 of a
plastic material is positioned over the gripping section 78 and the
lower portion 66.
The middle section 68 of the body portion 61 may be designed in a
manner in which it has an axially extending bore 84 which extends
longitudinally therethrough such as to properly balance the mass of
the brush to maintain maximum amplitude of vibration at the output
end or tips 85 of the respective bristle clusters 15. The bristle
clusters 15 are positioned in a plane substantially normal to the
longitudinal axis of the body portion 12 but each individual
cluster includes a plurality of bristles 21 that are essentially
folded over as seen in FIG. 13 and retained in place by retaining
means 90 in the form of a staple 92 having spaced apart prong
portions 94 with tips 95 and a connecting portion 96.
Accordingly, each bristle cluster 15 is assembled into an aperture
98 generally of a circular cross-sectional area having an opening
100 at the face surface 102 of the head portion 65 and extending
axially the distance generally in the range of 0.10 inch to 0.250
inch in depth such that each bristle element 21 is formed in a
U-shaped manner and held in place by the rib portion 96 of the
staple 92 as the prongs 94 are imbedded into the plastic material
of the head portions 65. In this manner, by automatic assembly
equipment, the bristle clusters 15 are inserted within the
respective apertures 98 and initially held in place. The head
portion 65 may have a rectangular cross-section as seen in FIG. 11
whereas the middle portion 68 may be or a circular cross-sectional
area with a radius 104 blending the two sections together.
Applicants discovered that the mere introduction or retention of
the bristle clusters 15 within an aperture 98 was not sufficient to
permit a transmitting of the ultrasonic energy to the respective
bristle elements or strands 21 so as to affectuate efficient
ultrasonic motion at the bristle tips 85. It is for this reason
that applicants discovered that transmitting means 105 was required
in order to permit proper acoustical transmission of the
vibrational energy waves from the head portion 65 to the respective
individual bristles 21. To accomplish this, applicants devised a
process wherein the bristles 21 were exposed to a chemical solution
106 having the ability to form a bond for transmission of the
energy waves.
Accordingly, to obtain the proper transmission of mechanical
vibratory energy both in the sonic range generally in the frequency
range of 0.01 KHz to 1 KHz and in the ultrasonic range of 5 KHz to
50 KHz, applicants utilize the process of manufacture in which the
aperture 98 to receive the bristle clusters 15 are generally
approximately 30 percent larger than those used in standard brush
manufacturing procedures to allow for lesser yield of the
thermoplastic material which may be a polycarbonate of various
types; i.e., Lexan, Merlon or Polycarbafil. The next step of the
manufacturing procedure is to elevate the temperature of the
thermoplastic material to a temperature which prevents fracturing
of the material upon the insertion of the bristle cluster 15 and
the staple 92. Applicants have found that for Lexan material, that
the Lexan may be just heated as by inserting in boiling water prior
to the insertion of the combined staple 92 and bristle cluster 15
with the temperature of the Lexan being at approximately
212.degree.F. Furthermore, applicants have found that it is
possible to use the highest possible density; i.e., maximum number
of bristles per staple bunch to make the tightest fit for the
insertion thereof. In addition, the staple selected is one having a
rounded cross-sectional area rather than a cutting type than is
used in certain conventional toothbrushes. This is important in
that it prevents partial cutting of the bristles and possible
subsequent fatiguing at the point of cut and in turn, a fracturing
of the bristle thereby reducing its energy transmission
properties.
To assure that the energy is transmitted, the coupling agent which
may be in the form of a solvent which causes a flow of the aperture
wall as seen in FIG. 15 to the interstices as by the formation of a
plurality of fingers 106 that secure each bristle 21 for energy
coupling. Accordingly, the solvent is used and causes a flow of the
thermoplastic material in the aperture 98 around the staple 92 and
bristles 21 thereby assuring proper coupling of the vibratory
energy. One type solvent used is Methylene Chloride which is
applied when the brush head 61 is at an elevated temperature in the
range of 100.degree.F. to 250.degree.F. As seen, this flow of the
brush head portion 65 causes an interlocking relationship such that
essentially major air gaps are eliminated. In this way the
mechanical vibratory energy is properly transmitted to the
individual bristles 21 from the brush head 65.
A further novel feature of the present invention is that the ends
85 of each bristle 21 as seen in FIG. 16 are "rounded" such that
the sharp points and burrs produced by cutting to size are
eliminated. The process for eliminating the sharp points can be
attained by either abrasive blasting in that an abrasive compound
driven by air pressure being directed against the bristle ends 85
occurs, or another approach is a heating of the bristle ends 85 to
cause a momentary softening of the bristle ends and the bristle
ends 85 tends to flow and produce a ball-type end 86 to avoid the
sharp edge. Applicants have found that the use of Nylon material
proves to be most satisfactory for the material from which the
bristles 21 are made. The bristle diameter may be in the range of
0.004 inch to 0.020 inch and extend from the brush head a length
from 0.30 inch to 0.60 inch. For example, for a bristle cluster
that includes eighty ends, the bristle element may have a diameter
of 0.008 inch and the aperture 98 a diamater of 0.093 inch and a
depth of approximately 0.120 inch.
Now referring more particularly to FIGS. 17-20, there is
illustrated the applicator means 10j which may be manufactured as
by injection moulding and is designed to be used with the
ultrasonic instrument means as previously illustrated. The
applicator means 10j includes a base or body section means 12j with
a longitudinally spaced apart ends 63j and 64j and having a brush
head or head 65j portion which is the upper section in which the
bristle clusters 15j are contained and a spaced apart lower portion
or end 66j with a middle section or portion 68j extending
therebetween. The body portion 12j which is preferrably made out of
a thermoplastic material such as Lexan has associated therewith
securing means 70j at the lower portion 66j in the form of a
securing member 72j inserted at one end thereof having a mating
portion 74j which is adapted to be secured as by moulding in the
lower portion 66j. 200 the To be maintained firmly in place, an
annular recess or depression 108j is provided to maintain intimate
coupling between the portion 74j and the surrounding lower portion
66j.
The lower portion 66j includes a gripping section 78j which is
shown to be of a shape with indents 110j so as to be readily
grasped between fingers of the user for obtaining the disengagement
of the applicator means 10j from the oral device. A stud 80j
extends from the securing means 70j approximate the gripping
section 78j and has a thread that may be of a quick type in that it
is not a fine thread so that a minimal number of turns of the
applicator means 10j is required before the bottom edge 64j abuts
the complimentary surface of the instrument means.
The bristle clusters 15j may be coupled in position as discussed
above.
Along the line of improved efficiency factors belongs the providing
on the brush head 65j with a material which prevents transmission
of high frequency vibratory energy into liquids or teeth or gums.
This is readily accomplished, for example, with a closed cell
rubber guard or insulating means 115j which may be in the form of a
cap 116j. The insulating means may be made of a foam polystyrane or
closed cell rubber which presents to the vibrating surface an
acoustic impendance equivalent to that of an air film. The acoustic
impedance of air is so mismatched (i.e., so much smaller) than the
acoustic impedance of the brush head 65j that all ultrasonic energy
waves arriving at the brush head-closed cell film interface will be
almost totally reflected back into the plastic thereby making more
energy available to the bristle clusters 15j to do their work. The
cap 116j may be moulded in place and cover substantially just the
brush head 65j or the complete brush 10j. If desired the cap or
cover 116j may be of a snap-fit onto the brush head 65j as shown
with spaced apart side walls 117j, end walls 118j end top wall 119j
integrally formed with each other.
Turning now to FIGS. 21 and 22 we have illustrated one of the
desired objectives of the invention which relates to the individual
bristles of each cluster to deliver their ultrasonic vibrational
energy to the load (i.e., gingival and tooth surfaces) as
effectively as possible. This means, in detail, that we are trying
to deliver a number of types of transfers relating to:
1. Cavitation (for pervasive interproximal effects)
2. Micromassage (for stimulation of local tissue
microstructures)
3. Other sonochemical and sono - physiological effects (such as
desensitizing, anaesthetizing, mouth wash "psychological" action,
fluoride penetration, etc.)
It is found that the overall effectiveness of a straight bristle
21k as illustrated in FIG. 21 in certain instances, is less than a
crimped bristle 21m of the type illustrated in FIG. 22 for the same
basic diameter. The technical reasons for the difference in
behavior are difficult to pinpoint because of the complex character
of the vibration transfer from the base of the bristle cluster to
the individual bristle of the cluster. But essentially the
longitudinal motion of the brush head 65k and 65m as indicated by
the double headed arrow 60k and 60m is translated into a flexural
type motion at the bristle tips as indicated by double headed
arrows 111k and 111m.
With respect to cavitation effects, the increased surface area is
undoubtedly a cause for increased efficiency. The "curliness" also
provides a more universal field of motional vibration components
which increases the overall effectiveness of the various actions.
Especially in connection with cleaning out alba (the white matter
between teeth due to food) and plaque (the gel-like substance
produced by salivary bacteria) which are both soft, the crimped or
curly cluster of bristles 21m has a "spring-back" action
characteristic of springy curls or spiral springs, which is a
combination of the stick-slip effect due to the pulsed on-off
bursts of ultrasonic energy packets and the low frequency action
consequent on this effect and referenced elsewhere in this
specification.
Thus, although the crimped bristles are not essential to the
operation of the disclosed invention, they nevertheless represent a
novel feature of the invention itself, being one of the many
disclosed items which increases the effectiveness of the tooth
hygiene desired.
Turning now to FIGS. 23-26, there is illustrated the applicator
means 10 in use in a dental cleaning procedure in accordance with
the invention in operative position in the oral cavity 120 against
the teeth 122. In accordance with the invention, the brush bristles
21 of the applicator means 10 is positioned against the teeth 122
in the usual manner during the brushing operation. That is, the
bristle clusters 15 are inserted in the mouth and positioned
adjacent the tooth surfaces 124 with a relatively light pressure.
The bristle clusters 15 may be moved manually to pass the brush
portion across all of the tooth surfaces, the bristles 21 randomly
assume positions in contact with and displaced from tooth surfaces.
Since in the case of manual brushing, the bristle tips 85 rarely
assume positions such that they extend deeply into the
interproximal areas 126 the present brush is designed to
approximate the curvature thereof.
In this manner the action between the sonic motion and ultrasonic
motion is believed to result in a combination effect such that the
beneficial features of each frequency is simultaneously
obtained.
Accordingly, the removing of plaque of 128 on the tooth surface 124
and foreign deposits 130 are obtainable with the present invention.
In FIG. 23 plaque 128 is illustrated as a layer of material that
has adhered to the surfaces of the teeth 122. Plaque is a soft
gelatinous substance produced in the mouth by the action of
salivary and sub-gingival bacteria, hardens into calculus in a
period of from two to twelve days, and is believed to be a
significant factor in causing periodental diseases.
In use, the ultrasonic bristles clusters 15 are vibrated so as to
introduce a micro-motion and a macro-motion to the teeth surfaces
as by generating ultrasonic vibrations as illustrated by the
double-headed arrow 60 in the bristle elements 21 at the working
end of the hand held ultrasonic motor that is in turn coupled to
the brush head 65. By amplitude modulating the ultrasonic
vibrations at a sonic rate there is produced alternating periods of
ultrasonic vibrating activities at the bristle elements and periods
of rest or substantially zero ultrasonic vibrations. Then by
engaging the bristle tips 85 against the teeth surface 124 and
maintaining a relative moving relationship there is generated
sufficient action to remove the plaque 128 and interproximal
deposits 130.
This action is generally obtained by providing a fluid film as
illustrated by the particles 132 which may be in the form of a
dentifrice having certain characteristics or simply that of saliva.
The motion at the bristle tips 85 is of sufficient amplitude of
vibrations to also produce a cavitational action in the fluid film
132 by the bristle elements 21.
Accordingly, FIGS. 23-26 inclusive are diagrammatic views helpful
in explaining how the interrelated phenomena are believed to
simultaneously occur to obtain the improved cleaning results. The
user applies the applicator means 10 in a manner so as it is
longitudinally vibrated in the direction of two-headed arrow 60
with respect to microscopic action. Mechanical vibratory energy is
transmitted to the free ends 85 of bristle clusters 15 and through
a fluid or other medium 132, or directly by contact with teeth
surface 124.
In use then, the applicator means 10 is inserted in the oral cavity
of the user and may be maintained in fixed position relative to a
number of teeth as, for example, illustrated in FIG. 23 such that
the cavitational and other actions may occur as the bristle
clusters 15 are maintained in relatively light contact with the
teeth surface 124 as well as the gingival surfaces of the mouth. If
the user desires, he may move the applicator means 10 across the
surface of the teeth as well as the gingival surfaces to obtain the
desired results. When movement occurs, the bristle clusters will
assume various positions and, for example as seen in FIG. 26, two
bristle clusters 15 are in contact with a single tooth 122 so that
the plaque material 128 may be microscopically removed therefrom.
The ultrasonic energy introduces the micro-motion in the bristle
clusters 15 which is responsible for certain cavitational effects
that will be engendered between various clusters 15 depending upon
the particular fluids 132 in use and the make-up thereof.
Accordingly, the inducement of the vibrations in the bristle
elements are at an ultrasonic range of 10KHz to 500KHz to vibrate
the bristle elements longitudinally and the vibration of the
bristle elements at a low sonic frequency at the range of 0.01 KHz
to 1 KHz produces the cleaning. As the brushing occurs there is
maintained an amplitude of vibrations at the bristle elements 21
sufficient to obtain a cavitational action on the teeth surfaces
124.
The bristle elements 21 as seen particularly in FIG. 26 may have a
contoured surface configuration that lend themselves to conform to
the contour of teeth 122 such that the bristle elements form a
surface consisting of a multiple number of pointed members
interproximately of the teeth during the brushing thereof which
produces peak accelerations in the bristle elements.
One aspect of the present invention is to provide insulating means
115 that may surround the toothbrush head 65 to improve efficiency
in that the insulating means 115 may be of a material which
prevents transmission of high frequency vibratory energy into
liquid or teeth or gums.
This is readily accomplished, for example, with a closed cell
rubber sheet. The closed cell material presents to the vibrating
surface an acoustic impedance equivalent to that of an air film.
The acoustic impedance of air is so mismatched (i.e., so much
smaller) than the acoustic impedance of the brush head plastic 65
that all ultrasonic energy waves arriving at the brush head-closed
cell firm interface will be almost totally reflected back into the
plastic thereby making more energy available to the bristle
clusters 15 to do their work.
For example, a very mild abrasive dentifrice could be used or, if
desired, saliva or regular water may be used depending upon the
condition of the user's mouth at the time he starts using the
present invention. The macro-motion provided by the low sonic
frequency energy in a sense permits a flushing away aspect in that
gross motion is simultaneously obtained with respect to the
interaction between the various frequencies and thereby helps in
the manual rushing concept. The low sonic rate also helps the user
psychologically in knowing that the instrument is working, since
the ultrasonic aspect is above the audible range of the user.
Furthermore, a micro-massage of the gums of the user is also
obtained. The utilization of the applicator means 10 is such that
it may be positioned against the various surfaces of the teeth as
illustrated in FIGS. 24, 25, and 26 as would normally be the case
with the positionment of a conventional cleaning operation.
The ultrasonic energy available at the bristle tips provide a
number of beneficial results, which result in the plaque and other
foreign deposits to be removed from the teeth. Accordingly, the
brush of the present invention permits stimulation of the gingival
tissue by macro-massage and micro-massage which has been found
beneficial for dental health, and massage also results in more
blood circulation than is obtained by conventional brushing
techniques.
The angular positionment of the bristle clusters 15 with respect to
the applicator means 10 are substantially normal to the
longitudinal mode of vibration, but these may be varied, as well as
the fact that an oscillatory or radial mode of macromotion may also
be applied to the applicator means 10 other than pure longitudinal
motion. Furthermore, the length and stiffness of the various
bristles may be varied within the confines of the present invention
and the beneficial results may still be obtained.
Referring now to FIG. 27, applicants herein disclose the mothod of
manufacture of the brush previously described and ideally suited
for use with an instrument that drives it at an ultrasonic as well
as sonic rate. Initially, the ultrasonic applicator or brush 10 is
formed either by machining or injection molding such that the brush
head portion has a plurality of the spaced apart apertures 98
contained therein and adapted to receive a plurality of individual
bristles therein.
By conventional equipment well known in the art, the step of
inserting and stapling the respective bristle clusters 15 in each
respective aperture 98 is accomplished and may be carried on on an
automatic process. It has been found that, if the stapling
operation occurs when the brush head is at room temperature, that a
certain degree of cracking or crazing will occur as the staple is
driven into the brush head or more particularly when the brush is
ultrasonically vibrated. Accordingly, the brush head by heating is
elevated to a temperature in the range of 100.degree.F to
250.degree.F, and for Lexan about 212.degree.F prior to stapling
each bristle cluster 15 in place. The staple is of a conventional
form and, for example, may be of 0.024 inch diameter made of 302
stainless steel, 1/4 hard.
After this is accomplished, the temperature of the brush head for a
brush made of Lexan material is raised to and stabilized at
approximately 135.degree.F, and the entire brush or the brush head
alone, is dipped in a liquid solvent such as methylene chloride,
such that the applying of the solvent covers the entire brush and
particularly seeps into the points between the aperture wall and
the outer surface of the respective bristles of the clusters. After
this occurs, the excess solvent may be removed by an air jet or
other means. The next step in the operation is the drying of the
brush such that the solvent is removed and this may occur by
returning the brush to the oven which may be at a temperature of
approximately 150.degree.F and retaining the brush in the oven at
that temperature for approximately one half hour. As a result of
the above steps, there occurs a flow of the plastic in the brush
head portion into surrounding relationship of the bristles in each
aperture therein such that the plastic solidifies in adhesive
relationship to the bristles to transmit the ultrasonic vibratory
energy from the brush head portion to the bristles. The fluidized
plastic produces intermittent molecular contact to fill the
interstices and provide an adhesion for acoustical transmission of
energy. Accordingly, the brush of the present invention is
manufactured and proper transmission of the vibratory energy is
obtained as previously explained.
generally subsequent to the above, the next step is that of
trimming or cutting of the bristle clusters to a desired shape as
by shearing thereof such that the vibratory tips of the bristles
may have the configuration desired.
The next step in the manufacture is the finishing of the bristle
tips 85 to a desired shape or contour and this may occur as by sort
of a polishing or sand blasting process or, if desired, the tips 85
of the respective bristle elements 21 may be exposed to a heat
source so, as seen in FIG. 16, a rounded edge occurs.
If the brush is designed in that the securing means are coupled to
the brush as by threads, then prior to elevating the temperature of
the brush for stapling, the solvent or wetting agent may be applied
to the threaded portion 74 of the securing member 72 as well as to
the thread 76 of the brush and then the parts may be screwed
together tightly and the temperature of the entire brush elevated
as discussed above prior to dipping of the entire brush in the
solvent.
In addition, the step of applying the sleeving 88 to the brush is
accomplished by using a shrink-type tubing that is axially slipped
over the body and the securing means 70. Subsequent thereto, the
temperature of the sleeving may be increased as by applying heat
thereto and shrinking the tubing in place.
To acoustically insulate the head portion 65 of the brush 10 from
its transmission of vibratory energy to the cheek of the user, an
insulating material may be secured to the head portion as by an
adhesive or other means.
CONCLUSION
Accordingly, the toothbrush hereinabove illustrated is one
embodiment that may be employed with a power handle so as to
properly deliver the ultrasonic vibrational energy to the bristle
tips and be suitable for production on a mass basis. It will be
appreciated by those skilled in the art that various modifications
and devices may occur to the disclosure of the present invention,
but the same are generally illustrated as being secured to the
power source by securing means that may vary in shape or size and
that the means may even be an integral part of the brush itself and
be molded therewith to eliminate the necessity of another component
part to be added to the brush.
While certain novel features of this invention have been disclosed
herein and are pointed out in the claims, it will be understood
that various ommissions, substitutions, and changes may be made by
those skilled in the art, without departing from the teachings of
the invention.
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