U.S. patent application number 10/735666 was filed with the patent office on 2004-07-08 for toothbrush with longitudinal to lateral motion conversion.
This patent application is currently assigned to Ramy Weitz. Invention is credited to Ben-Ari, Tsafrir.
Application Number | 20040128784 10/735666 |
Document ID | / |
Family ID | 34700437 |
Filed Date | 2004-07-08 |
United States Patent
Application |
20040128784 |
Kind Code |
A1 |
Ben-Ari, Tsafrir |
July 8, 2004 |
Toothbrush with longitudinal to lateral motion conversion
Abstract
A toothbrush has a toothbrush head supported by an elongated
handle which defines an axis. A number of brush elements mounted on
the toothbrush head, each including at least one tuft of bristles,
have a dimension parallel to the axis being no more than about 5
mm. Each brush element assumes a released state projecting upright
from the toothbrush head, and can be deflected in a given direction
defined by a motion delineating configuration. The direction of
deflection is at an angle of between about 15.degree. and about
75.degree. to the axis and perpendicular to a bristle extension
direction.
Inventors: |
Ben-Ari, Tsafrir; (Shimshit,
IL) |
Correspondence
Address: |
DR. MARK FRIEDMAN LTD.
C/O BILL POLKINGHORN
DISCOVERY DISPATCH
9003 FLORIN WAY
UPPER MARLBORO
MD
20772
US
|
Assignee: |
Ramy Weitz
|
Family ID: |
34700437 |
Appl. No.: |
10/735666 |
Filed: |
December 16, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10735666 |
Dec 16, 2003 |
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10230206 |
Aug 29, 2002 |
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10230206 |
Aug 29, 2002 |
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09618465 |
Jul 18, 2000 |
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6477729 |
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Current U.S.
Class: |
15/167.1 ;
15/201 |
Current CPC
Class: |
A46B 7/06 20130101; A46B
2200/1066 20130101; A46B 9/12 20130101 |
Class at
Publication: |
015/167.1 ;
015/201 |
International
Class: |
A46B 009/04 |
Claims
What is claimed is:
1. A toothbrush comprising: (a) a toothbrush head attached to, or
integrally formed with, an elongated handle, a direction of
elongation of said handle being referred to as an axis; and (b) a
plurality of brush elements associated with said toothbrush head,
each of said brush elements including at least one tuft of
bristles, a dimension of each of said brush elements parallel to
said axis being no more than about 5 mm, wherein each of said brush
elements assumes a released state projecting substantially upright
from said toothbrush head, and wherein each of said brush elements
is associated with a motion delineating configuration which defines
a preferred direction of deflection of at least part of said brush
element, said preferred direction of deflection being substantially
perpendicular to a bristle extension direction and at an angle of
between about 15.degree. and about 75.degree. to said axis.
2. The toothbrush of claim 1, wherein said dimension of each of
said brush elements parallel to said axis is no more than about 3
mm.
3. The toothbrush of claim 1, wherein each of said brush elements
includes exactly one tuft of bristles.
4. The toothbrush of claim 1, wherein said preferred direction of
deflection is at an angle of between about 30.degree. and about
60.degree. to said axis.
5. The toothbrush of claim 1, wherein said preferred direction of
deflection is at an angle of between about 40.degree. and about
50.degree. to said axis.
6. The toothbrush of claim 1, wherein said motion delineating
configuration includes a flexible shaft portion of each of said
brush elements, said shaft portion being constructed so as to
exhibit a preferred direction of flexing corresponding to said
preferred direction of deflection.
7. The toothbrush of claim 6, wherein said flexible shaft portion
has a cross-sectional shape with a major dimension and a minor
dimension, said minor dimension being no more than two thirds of
said major dimension so as to define said preferred direction of
flexing.
8. The toothbrush of claim 1, wherein said motion delineating
configuration includes a hinge arrangement defining an arcuate path
of at least part of said brush element.
9. The toothbrush of claim 8, wherein said hinge arrangement
includes a hinge formed as part of said brush element.
10. The toothbrush of claim 8, wherein said hinge arrangement
includes a hinge formed between said brush element and said
toothbrush head.
11. The toothbrush of claim 8, wherein said hinge arrangement
includes a substantially cylindrical pin element inserted into a
complementary socket.
12. The toothbrush of claim 1, wherein said motion delineating
configuration includes an elongated slot associated with said
toothbrush head for limiting movement of said brush element to a
predefined direction.
13. The toothbrush of claim 1, wherein said motion delineating
configuration includes an elongated slot formed in said toothbrush
head within which said brush element is slidably mounted.
14. The toothbrush of claim 1, wherein said motion delineating
configuration includes a resilient element deployed to bias said
brush element to return to said released state.
Description
[0001] This is a Continuation-In-Part of application Ser. No.
10/230,206 filed Aug. 29, 2002, which is itself a
Continuation-In-Part of application Ser. No. 09/618,465 filed Jul.
18, 2000, now issued as U.S. Pat. No. 6,477,729.
FIELD AND BACKGROUND OF THE INVENTION
[0002] The present invention relates to toothbrushes and, in
particular, it concerns a toothbrush with longitudinal to lateral
motion conversion.
[0003] It is known that best results are achieved by brushing teeth
with an upwards and downwards action, thereby helping to remove
food material stuck in the cracks between adjacent teeth. In
practice, however, only a small proportion of users actually take
the trouble to perform such a brushing action. Instead, most users
revert to the much easier, but less effective, side-to-side
brushing action.
[0004] In power-driven toothbrushes, this problem is commonly
addressed by causing vibration or rotation of brush elements
perpendicular to the handle (which is generally parallel to the
side-to-side primary direction of motion). Examples of power-driven
toothbrushes which employ such an action may be found in U.S. Pat.
No. 2,583,886 to Schlegel, U.S. Pat. No. 2,665,675 to Grover, and
U.S. Pat. No. 5,864,911 to Arnoux et al.
[0005] In the field of manual toothbrushes, however, the problem is
not so readily solved. A wide variety of toothbrush structures have
been proposed in an attempt to produce a secondary up-down motion
even when the user only actively moves the toothbrush in a
side-to-side primary direction of motion. Many of these employ
rotatable bristle-carrying elements deployed so as to rotate about
an axis perpendicular to the primary direction of motion. Examples
of such structures may be found in U.S. Pat. No. 5,142,724 to Park,
U.S. Pat. No. 5,186,627 to Amit et al., and U.S. Pat. No. 5,996,157
to Smith et al. An alternative approach is suggested in U.S. Pat.
No. 1,643,217 to Lazarus, where a spiral arrangement of bristles
extends along a rotatable shaft rotatably mounted parallel to the
primary direction of motion. None of these proposed structures,
however, has been found particularly effective.
[0006] Co-assigned U.S. Pat. No. 6,477,729 from which this
application indirectly takes priority discloses a toothbrush
structure in which bristle wheels are deployed with their axes at
an angle to the direction of motion so that rotation generated by
motion of the toothbrush in contact with the teeth generates a
component of brushing motion transverse to the direction of motion.
The principle of operation of this structure is illustrated in FIG.
8 where the primary brushing motion is assumed to be parallel to an
axis defined by the length of the toothbrush handle and one or more
brush element is configured to define a direction of bristle
freedom of motion at an angle between about 15.degree. and
75.degree. to the axis. This structure is highly advantageous in
that it very effectively converts side-to-side motion into an
up-down brushing effect. It would be considered advantageous,
however, to provide a similar effect without requiring the somewhat
unusual bristle wheels proposed therein, thereby allowing the
toothbrush to maintain a "look" and "feel" more similar to a
conventional tufted toothbrush.
[0007] U.S. Pat. Nos. 5,398,366 and 5,269,038 to Bradley, and U.S.
Pat. No. 5,481,775 to Gentile et al., disclose a number of
toothbrush designs which attempt to implement a similar concept of
longitudinal-to-lateral movement conversion. In each case of the
Bradley patents, the toothbrush bristles are subdivided between
four rectangular brush elements each of which is restrained so as
to perform a rocking or sliding motion at an angle inclined with
respect to the length of the handle. In the embodiment of the '038
patent and two of the embodiments of the '366 patent, each brush
element is hinged or rotatably connected to the toothbrush head so
as to perform a rocking motion. In a third embodiment in the '366
patent, each brush element performs an angled sliding motion. In
the Gentile et al. patent, the entire brush assembly is cylindrical
and moves along slots defining a helical path.
[0008] Although the toothbrush structures of Bradley and Gentile et
al. are based on a concept similar to that of the aforementioned
U.S. Pat. No. 6,477,729, the proposed structures are of very
limited efficacy in practice. Specifically, in all of the
implementations of Bradley using a rocking motion, the rectangular
brush elements can only rock if the regions far from the axis of
rotation perform primarily a up-down motion towards and away from
the surface of the teeth. As a result, the contact of the brush
element with the surface of the teeth effectively prevents
significant rocking motion. Furthermore, even in the case of the
sliding motion embodiment of Bradley and the helical motion
embodiment of Gentile et al., any longitudinal-to-lateral motion
conversion occurs only once per stroke immediately after reversal
of the direction of motion.
[0009] The latter problem is illustrated clearly in FIGS. 1A-1C
which shows schematically a single brush element 100 corresponding
to one of the four elements of Bradley or the single element of
Gentile et al. It will be noted that the head of a conventional
toothbrush typically includes a region of at least about 3 cm
length provided with bristles. Thus, the Bradley references clearly
refer to brush elements of length 1.5 cm or greater. During motion
of the brush element along a row of teeth 24 as illustrated, the
bristles 102 of each brush element are continuously in contact with
at least one, and typically two, teeth at all times. Although
individual bristles (102') may instantaneously be released from
contact, the brush element 100 as a whole is subject to continuous
frictional contact with the teeth as it moves. As a result, once
the brush element has reached one extreme of its rocking or sliding
motion near the beginning of each stroke, it remains lodged at the
extreme of the range of motion for the remainder of each brushing
stroke and fails to generate any transverse brushing motion,
instead brushing parallel to the direction of movement like any a
conventional toothbrush.
[0010] There is therefore a need for a toothbrush with longitudinal
to lateral motion conversion which would allow groups of bristles
to perform repeated longitudinal-to-lateral motion conversion
during each brush stroke along the teeth.
SUMMARY OF THE INVENTION
[0011] The present invention is a toothbrush with longitudinal to
lateral motion conversion.
[0012] According to the teachings of the present invention there is
provided, a toothbrush comprising: (a) a toothbrush head attached
to, or integrally formed with, an elongated handle, a direction of
elongation of the handle being referred to as an axis; and (b) a
plurality of brush elements associated with the toothbrush head,
each of the brush elements including at least one tuft of bristles,
a dimension of each of the brush elements parallel to the axis
being no more than about 5 mm, wherein each of the brush elements
assumes a released state projecting substantially upright from the
toothbrush head, and wherein each of the brush elements is
associated with a motion delineating configuration which defines a
preferred direction of deflection of at least part of the brush
element, the preferred direction of deflection being substantially
perpendicular to a bristle extension direction and at an angle of
between about 15.degree. and about 75.degree. to the axis.
[0013] According to a further feature of the present invention, the
dimension of each of the brush elements parallel to the axis is no
more than about 3 mm.
[0014] According to a further feature of the present invention,
each of the brush elements includes exactly one tuft of
bristles.
[0015] According to a further feature of the present invention, the
preferred direction of deflection is at an angle of between about
30.degree. and about 60.degree. to the axis, and most preferably,
between about 40.degree. and about 50.degree. to the axis.
[0016] According to a further feature of the present invention, the
motion delineating configuration includes a flexible shaft portion
of each of the brush elements, the shaft portion being constructed
so as to exhibit a preferred direction of flexing corresponding to
the preferred direction of deflection.
[0017] According to a further feature of the present invention, the
flexible shaft portion has a cross-sectional shape with a major
dimension and a minor dimension, the minor dimension being no more
than two thirds of the major dimension so as to define the
preferred direction of flexing.
[0018] According to a further feature of the present invention, the
motion delineating configuration includes a hinge arrangement
defining an arcuate path of at least part of the brush element.
[0019] According to a further feature of the present invention, the
hinge arrangement includes a hinge formed as part of the brush
element.
[0020] According to a further feature of the present invention, the
hinge arrangement includes a hinge formed between the brush element
and the toothbrush head.
[0021] According to a further feature of the present invention, the
hinge arrangement includes a substantially cylindrical pin element
inserted into a complementary socket.
[0022] According to a further feature of the present invention, the
motion delineating configuration includes an elongated slot
associated with the toothbrush head for limiting movement of the
brush element to a predefined direction.
[0023] According to a further feature of the present invention, the
motion delineating configuration includes an elongated slot formed
in the toothbrush head within which the brush element is slidably
mounted.
[0024] According to a further feature of the present invention, the
motion delineating configuration includes a resilient element
deployed to bias the brush element to return to the released
state.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The invention is herein described, by way of example only,
with reference to the accompanying drawings, wherein:
[0026] FIGS. 1A-1C are schematic illustrations of a sequence of
positions during brushing of the teeth of a user with a toothbrush
according to the teachings of U.S. Pat. No. 5,269,038 to
Bradley;
[0027] FIGS. 2A-2C are schematic illustrations of a sequence of
positions during brushing of the teeth of a user with a toothbrush
constructed and operative according to the teachings of the present
invention;
[0028] FIG. 3 is a schematic isometric view of the head of a
toothbrush illustrating multiple options for implementations of a
brush element according to the teachings of the present
invention;
[0029] FIG. 4 is a side view showing the structure of the brush
elements for each implementation illustrated in FIG. 3;
[0030] FIGS. 5A and 5B are schematic isometric views of two
implementations of a dirt cover for use with certain brush elements
from FIG. 3;
[0031] FIG. 6 is a schematic isometric view of a hinge pin
structure for use in certain brush element implementations of FIG.
3;
[0032] FIGS. 7A and 7B are schematic plan views of the toothbrush
of FIGS. 2A-2C showing two exemplary deployments of brush elements
according to the teachings of the present invention; and
[0033] FIG. 8 is a schematic illustration of the geometrical
relationship between direction of toothbrush movement and preferred
direction of brush element deflection which underlies operation of
the present invention and the related prior art.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0034] The present invention is a toothbrush with longitudinal to
lateral motion conversion.
[0035] The principles and operation of toothbrushes according to
the present invention may be better understood with reference to
the drawings and the accompanying description.
[0036] Referring now to the drawings, FIGS. 2A-2C illustrate the
operation of a toothbrush, generally designated 10, constructed and
operative according to the teachings of the present invention.
Generally speaking, toothbrush 10 includes a toothbrush head 12
attached to, or integrally formed with, an elongated handle 14.
Toothbrush head 12 supports a plurality of brush elements 16 each
including at least one tuft of bristles 18. Each brush element 16
assumes a released state 20 projecting substantially upright from
the toothbrush head, and can be deflected, independent of the other
brush elements, in a preferred direction of deflection (e.g. to
position 22), the direction being substantially perpendicular to a
bristle extension direction and at an angle of between about
15.degree. and about 75.degree. to an axis 15 defined by a
direction of elongation of handle 14, thereby providing
longitudinal-to-lateral motion conversion according to the
principle illustrated in FIG. 8 described above. Various examples
of motion delineating configurations for defining the preferred
direction of deflection will be discussed below with reference to
FIGS. 3 and 4.
[0037] It is a particular feature of the present invention, in
contrast to the devices of the aforementioned prior art, that a
dimension of each brush element 16 parallel to the axis is no more
than about 5 mm. In an alternative, but not necessarily identical,
approach to defining this feature, it is a particular feature that
each brush element has not more than three tufts of bristles 18
arrayed along the dimension parallel to the axis. This feature, as
defined by either or both of these criteria, tends to ensure that
each individual brush element 16 clears a tooth 24 and is allowed
to return from deflected position 22 to its upright position 20
before encountering the next tooth 24, thereby allowing each brush
element to perform repeated longitudinal-to-lateral motion
conversion cycles within each stroke of toothbrush 10. This motion
conversion, supplementing the motion conversion which occurs each
time the user changes direction between strokes, greatly improves
the overall efficacy of the motion conversion, and hence of the
overall brushing motion.
[0038] Before proceeding further with the description of the
present invention, it will be useful to define certain terminology
as used herein in the description and claims. Firstly, when
reference is made to a dimension of the brush elements 16 parallel
to the axis, the intention is to refer to the length parallel to
the axis of the portion of the brush element which is configured to
contact the teeth. Similarly, the measurement is made when the
brush element is upright and the bristles not flexed. Clearly, the
deflection of the brush element and flexing of the bristles may
produce temporary elongation in the direction parallel to the
axis.
[0039] In a further matter of terminology, reference is made to
deflection of the brush elements in a "preferred direction of
deflection". It should be appreciated that the deflection of the
present invention may be a bending motion, a pivotal motion, a
linear or curved sliding motion, or any other form of motion where
at least a distal portion of the brush element (i.e., furthest from
its point of association with the toothbrush head) moves in the
correspondingly defined direction. Where the motion is not linear,
the preferred direction of motion is taken to be the tangent to the
direction followed by the distal portion of the brush element
during the initial motion from the "released state". The
"direction" is typically, although not necessarily, a line of
motion extending symmetrically in two opposite directions from the
"released state" position.
[0040] When defining the geometrical features of the present
invention, reference is made to an axis defined by "the extensional
direction of the toothbrush handle". Conceptually, it is the
geometry with respect to the direction of motion which is essential
to proper operation of the present invention. The extensional
direction of the handle is chosen as a structural feature which is
related to the direction of motion. However, it will be noted that
toothbrush handles are often designed to be non-parallel to the
head of the toothbrush. For this reason, reference is made to an
"axis" defined by the handle configuration. This direction would
ideally be defined as the projection of the extensional direction
of the handle onto a plane of contact with the teeth. This
geometrical construct corresponds to the direction of motion which
will be performed by a typical user performing a side-to-side type
brushing action. For most purposes, an axis passing along the
length of the toothbrush handle is sufficient for evaluating the
geometrical definitions of the features of the present
invention.
[0041] With regard to the term "bristles", this is used herein
generically to refer to any and all fibers suited for use in
toothbrushes, including natural and synthetic bristles.
[0042] Turning now to the features of the present invention in more
detail, as mentioned before, according to a first way of defining
the present invention, the dimension of each brush element 16
parallel to the axis, i.e., the "length" of the brush element, is
no more than about 5 mm. Preferably, the dimension of each brush
element 16 parallel to the axis is no more than about 3 mm, and
most preferably less than 2 mm. These shorter elements are most
likely to return to their upright position between adjacent teeth,
thereby optimizing the longitudinal-to-lateral motion conversion so
that it occurs repeatedly along the length of each stroke and not
just immediately after reversal of the stroke direction. It should
be noted that the dimension of the brush elements 16 transverse to
the axis, i.e., the "width" of the brush elements as measured into
the page as viewed in FIGS. 2A-2C, is typically less critical to
the present invention, since an increased width does not
necessarily interfere with the righting of the brush elements
between teeth. Thus, the width may be less than, equal to, or
greater than, the length of the brush element 16. In a most
preferred implementation, the width and length are substantially
equal.
[0043] As mentioned earlier, the length of the brush elements may
alternatively be delimited in terms of numbers of tufts of bristles
arrayed along a direction parallel to the axis. A maximum number
according to this manner of defining the invention is typically
three tufts, and more preferably two tufts. Here too, the
limitation is specifically in the direction parallel to the axis,
and each brush assembly may in fact support rows of staggered tufts
of bristles. Thus, an element with three tufts arrayed along the
axial direction may correspond to as many as five or six staggered
interspaced laterally-extending rows of tufts. In preferred
implementations, the number of tufts arrayed laterally is
substantially the same as the number deployed along the length. In
one particularly preferred implementation used herein to exemplify
the present invention, each brush element 16 carries includes
exactly one tuft of bristles 18. In this case, the brush element 16
is typically implemented as a stem or shaft within which the
bristle tuft is mounted.
[0044] As mentioned earlier, each brush assembly is associated with
a motion delineating configuration for defining a preferred
direction of deflection substantially perpendicular to a bristle
extension direction and at an angle of between about 15.degree. and
about 75.degree. to the axis. More preferably, the preferred
direction of deflection is at an angle of between about 30.degree.
and about 60.degree., and most preferably, between about 40.degree.
and about 50.degree., to the axis. Various examples of motion
delineating configurations suitable for implementing the present
invention will now be described with reference to FIGS. 3 and
4.
[0045] Turning now to FIGS. 3 and 4, there is shown an assortment
of different preferred implementations for brush element 16 and the
corresponding motion delineating configuration. For the purpose of
concise presentation of these different options, they are shown
schematically in FIG. 3 in the context of a toothbrush head 12. It
will be understood that, in a practical implementation, a given
toothbrush will typically be implemented using a single structural
implementation for all brush elements 16, and that the brush
elements will be arrayed over substantially the entire area of
toothbrush head 12 with preferred directions of deflection on
symmetrically distributed on both sides of the axial direction.
[0046] Turning now to a first preferred implementation of brush
element, designated 16a, the motion delineating configuration is
here implemented using a flexible shaft portion 30 which is
constructed to as to inherently exhibit a preferred direction of
flexing. This may be achieved by using suitably oriented materials
with structurally non-isotropic properties, or by
structural/mechanical design which defines a direction of minimum
resistance to flexing. In the example illustrated here, flexible
shaft portion 30 has a cross-sectional shape with a major dimension
and a minor dimension, the minor dimension being no more than two
thirds, and preferably less than half, of the major dimension so as
to define the preferred direction of deflection. Such a structure
is sometimes referred to as an "integral hinge" and may readily be
implemented using various standard polymer production techniques.
Optionally, the thinning of the "minor dimension" of flexible
portion 30 may be less pronounced than is shown here, and may be
spread over a longer section of the shaft to offer increased
mechanical strength with a diffuse flexing motion rather than a
well defined "hinge".
[0047] In a second preferred implementation of brush element,
designated 16b, a flexible shaft portion 32 is flexible equally in
all directions and the motion delineating configuration includes an
elongated slot associated with the toothbrush head for limiting
movement of the brush element to a predefined direction. In the
case shown here, shaft portion 32 is sunken in to a shaped socket
34 in toothbrush head 12 and side-walls of socket 34 and/or edges
around the top of socket 34 define the elongated slot 36. Clearly,
an equivalent function could be provided without shaped sockets 34
by use of a slotted structure overlying toothbrush head 12.
[0048] In a third preferred implementation of brush element,
designated 16c, an enlarged base portion 38 of brush element 16c is
slidably mounted within an elongated slot 40 formed in the
toothbrush head. In contrast to the arcuate motion provided by the
other implementations of FIGS. 3 and 4, the motion of brush element
16c is a linear reciprocating motion.
[0049] The remaining preferred exemplary implementations of the
brush element shown in FIGS. 3 and 4 all employ a motion
delineating configuration including a hinge arrangement defining an
arcuate path of at least part of the brush element relative to the
toothbrush head 12. In the cases of brush elements 16d, 16e and
16f, the hinge arrangement includes a hinge formed as part of the
brush element, whereas in brush elements 16g, 16h and 16i, the
hinge arrangement includes a hinge formed between the brush element
and toothbrush head 12. In each case, the hinge arrangement
preferably includes a substantially cylindrical pin element
inserted into a complementary socket.
[0050] Referring briefly to the details of each example, brush
element 16d has a base portion 42 formed with hinge pin portions 44
projecting from both sides, and a pair of hinge brackets 46
associated with an upper portion of brush element 16d configured
for engagement over pin portions 44. Brush element 16f is a similar
structure where base portion 42 terminates in a cylindrical pin 48
at its upper end, and the upper portion of the brush element
features a complementary resilient C-shaped clip 50 configured to
snap into engagement with pin 48. Brush element 16e is similar to
16f but with the pin and clip reversed so that base portion 42
features the clip 50 and the upper portion features pin 48. In all
three cases 16d, 16e and 16f the hinge configurations are provided
with abutment surfaces on each side of the hinge to delimit a
maximum range of angular deflection, preferably chosen to be no
more than .+-.40.degree. from the upright position, and most
preferably no more than .+-.30.degree..
[0051] Turning now to brush elements 16g, 16h and 16i, as mentioned
above, these employ a hinge formed between the brush element and
toothbrush head 12. In the case of 16g, a transverse bore 52 in the
rounded base of the brush element receives partially-cylindrical
projections from each side of a shaped socket 54. In the case of
16h, this configuration is reversed with a cylindrical pin 56
formed at the base of the brush element snap-fitting into a
correspondingly shaped socket 58. In the case of 16i, engagement
between snap-fitting pin projections and a socket 60 occurs near
the top edge of an inwardly opening cavity 62 within which the
countersunk brush element base 64 moves. This latter configuration
ensures a small opening around the exposed part of the brush
element while the countersunk base 64 of the brush element moving
within the shaped cavity 62 provides structural support against
torque applied other than in the predefined direction of motion or
beyond the intended range of motion.
[0052] Referring briefly to FIGS. 5A and 5B, these show two cover
elements which are considered useful in certain implementations for
limiting ingress of dirt into a socket in toothbrush head 12 around
the base of the brush elements. The round cover of FIG. 5A is used
where the socket opening is localized, such as in brush element
16i. In implementations with an open slot, the elongated cover of
FIG. 5B is preferred. According to an additional, or alternative,
feature, any sockets formed within toothbrush head 12 may have
drainage channels open to the rear of the head to facilitate
though-flow of water for flushing-out toothpaste or dirt caught in
the socket.
[0053] Referring briefly to FIG. 6, this illustrates a possible
hinge-pin structure, in this case suited to the implementation of
brush element 16i from FIGS. 3 and 4. Clearly, by providing shaped
sockets for the pin projections to engage, a well-defined pivotal
hinge structure is generated. Details of the implementations of the
various other hinge structures shown schematically above will be
self-explanatory to one ordinarily skilled in the art by analogy to
this example.
[0054] It will be noted that the repeated longitudinal-to-lateral
motion conversion performed by each brush element during a single
unidirectional stroke of the toothbrush is dependent upon the brush
element returning at least part of the way from its deflected state
towards its upright state when released. In many cases, the natural
spring-back effect of bristles being momentarily released from
contact with a tooth carries sufficient momentum to flick the brush
element away from its extreme deflected position towards the
upright position. Preferably, however, in order to enhance
operation, the motion delineating configuration includes a
resilient element deployed to bias the brush element to return to
the upright released state. In the examples of brush elements 16a
and 16b described above, this is typically an inherent property of
the flexible shafts 30 and 32. In other implementations, a similar
effect is achieved by addition of a spring-like element (not
shown), typically implemented as one or more leaf-spring element
integrally molded with a plastic portion of the brush element base,
as is known in the art of molded plastic articles.
[0055] Parenthetically, it should be noted that the motion
delineating configurations of the present invention define at least
one preferred direction of deflection and may, in certain cases,
define more than one preferred direction of deflection for a brush
element. Thus, for example, in the case of brush element 16b, or
16h implemented with a ball-and-socket joint, an X-shaped slot may
be used to define two alternative preferred directions of
deflection, each at the required angle to the axis, between which
the brush element can switch freely. In an alternative
implementation, the stem of the brush element itself may be
implemented so as to provide two preferred flexing direction, such
as by use of a flexible stem portion with an X-shaped cross-section
which inherently offers resistance to flexing in the planes of the
X-walls while allowing flexing in the intermediate directions more
easily.
[0056] Finally, turning to FIGS. 7A and 7B, it will be noted that a
toothbrush head 12 typically carries at least about 10 brush
elements 16, and more typically between 20 and 50 such brush
elements. Preferably, roughly equal numbers of brush elements 16
have preferred directions of deflection on each side of the axis
defined by handle 14, e.g. .+-.45.degree. thereto, so as to avoid
generating a net lateral force which would tend to deflect the
entire toothbrush from the course intended by the user. The brush
elements 16 may be deployed in any desired distribution, covering
the entire available area of toothbrush head, or combined with
other brush elements such as conventional fixed bristle tufts. For
maximum brush density, it is particularly advantageous to arrange
the brush elements in partially interleaved staggered rows of
alternating directions of deflection. By way of example, FIG. 7A
illustrates a first preferred arrangement where brush elements 16,
represented by double-ended arrows indicating their directions of
deflection, are deployed in rows transverse to the toothbrush head
with alternate rows at .+-.45.degree. to the axis. FIG. 7B shows a
further example where rows of similar brush elements are deployed
substantially parallel to the axis, again with adjacent rows having
deflection directions rotated relative to the axis in alternating
senses. In both cases, at least three are preferably used, and more
preferably at least four.
[0057] It will be appreciated that the above descriptions are
intended only to serve as examples, and that many other embodiments
are possible within the scope of the present invention as defined
in the appended claims.
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