[0001] This invention relates to toothbrushes, and more particularly to a system of providing
toothbrushes of various configurations designed for improved cleaning of the mouths
of a wide variety of individual patients in conditions of increased asepticity.
[0002] Throughout the years of teaching oral hygiene to be used in the home, the dental
profession has generally recommended that a period of eight minutes is necessary with
the use of the manual brush to debride the mouth as well as break up bacterial plaque.
[0003] With the use of a power toothbrush, this time can be reduced to a four-minute period
with power movement.
[0004] However, both the power and manual techniques need the correct design of brush to
enable it to enter the areas where the majority of the problems occur in the oral
cavity (interproximal areas).
[0005] It is currently recognized that while it is desirable with each brushing to remove
as much bacterial plaque as possible from the interproximal spaces and from beneath
the free gingival margin as well as from the surfaces of the teeth, the bacteria in
the plaque which are responsible for tooth decay and gingival deterioration are inactivated
for periods of time up to twenty-four hours by isolation of the bacteria from their
grouping in a plaque form, that is, by disturbing the plaque formed on the teeth and
breaking up the grouping of the bacteria. Accordingly, it is being urged that teeth
be brushed in a rotary motion in an attempt to reach beneath the free gingival margin
rather than in a reciprocating movement parallel to the occlusal plane and also by
such rotary motion to avoid tooth structure erosion caused by reciprocating brushing.
[0006] Inasmuch as the structures of the toothbrushes currently available do not promote
the use of the desired rotary brushing motion nor provide means to facilitate reaching
into the interproximal spaces and beneath the free gingival margin, there is a present
need to provide a toothbrush which will not only discourage brushing parallel to the
occlusal plane and encourage as well as facilitate the desirable rotary brushing movement
but will also provide means for reachng the interproximal spaces and beneath the free
gingival margin.
[0007] Several proposals have been advanced to provide increased access to interproximal
and free gingival margin areas of teeth. Significant among these is U.S. patent no.
4,209,871 to Ernest, that patent being hereby incorporated by reference. While the
above-mentioned patent no. 4,209,871 discloses a toothbrush having a head which provides
increased accessability to the teeth, the specialized nature of the brush head meant
that it would be difficult to provide the brush in a wide variety of configurations.
For example, a store would have to carry different stocks for various combinations
of different manual and electrical toothbrush handles, as combined with bristles of
various types, varying degrees of firmness and heads of various sizes. Thus, a patient
having a relatively large mouth, a Broxident (TM) electrical toothbrush head and desiring
soft rounded tipped natural bristles would probably not be satisfied with a small
manually operated toothbrush having firm nylon bristles with shaved tips.
[0008] Additionally, a good home dental program may require the use of different toothbrush
designs. For example, if a patient brushed twice daily, he may wish to use a brush
which is adapted to maximize cleaning of gingival areas in the morning, and use a
brush which maximizes cleaning of interproximal areas before he retires. In certain
instances, a dentist may wish to prescribe the use of a certain type of toothbrush,
such as a toothbrush designed to treat certain periodontal disorders.
[0009] While the primary function of a toothbrush is cleaning, toothbrushes are notoriously
septic by their very nature. Micro-and microscopic particles are often lodged between
bristles. Likewise, particularly in humid climate, the bristles tend to remain septically
moist for long periods of time at room temperatures, often until the next use of the
toothbrush.
[0010] People have used various techniques in order to avoid septic conditions. In addition
to vigorously rinsing the toothbrush before and after each use, people often use multiple
toothbrushes, permitting a longer period of inactivity to exist between uses of a
particular toothbrush. Septic conditions have also discouraged the use of toothbrush
designs in which large amounts of bristles are used because these large amounts of
bristles makes it difficult to obtain dry condition of the toothbrush head.
[0011] Various disposable toothbrush designs have been advanced in the prior art. Notable
among these is U.S. patent no. 4,227,276 to Ginsburg, et al,, invented in part by
one of the co-inventors of the present invention; that patent being hereby incorporated
by reference.
[0012] The above-mentioned patent 4,227,276 discloses the use of a removable handle which
may be re-formed when heated in hot water. This presents a partial solution to another
problem in the prior art, that is the custom tailoring of toothbrush handles to the
indiviual user.
[0013] While particular shapes of toothbrush handles may be more desirable, it may be also
desirable to provide toothbrush handles which may be of particular highly specialized
or expensive variety with the brushes being disposable.
[0014] It may also be desired to provide toothbrushes with handles which would be used for
a variety of user applications. For example, if a user desired to use a toothbrush
while spending the night away from home, she may wish to have the convenience of portability.
She may also wish to have the convenience of using a particular toothbrush head configuration.
If she is visiting someone whom she knows has an electric toothbrush handle, she may
wish to have a handle which, if circumstances allow, permit her to attach her toothbrush
to the electric toothbrush handle in conditions which are reasonably aseptic.
[0015] U.S. patent no. 3,994,039 discloses various methods for brushing teeth, that patent
being hereby incorporated by reference. These methods include various combinations
of back-and-forth movement and vertical brush movement designed to effectively clean
the teeth and provide circulation at the gingival margin. In a similar matter, electric
toothbrushes have been designed to provide various brush movements, primarily in an
attempt to provide brushing action recommended by dentists. These include, in addition
to vertical and horizontal movements, vertical rolling movements and combinations
of horizontal and rolling movements. Recently, a short circular movement has received
widespread acceptability in the dental profession. These diverse movements have been
generally designed to be used with a single brush, usually having a simple rectangular
or round shape, with little attention to improving brush design as well.
[0016] It is accordingly an object of the invention to provide a system for permitting the
use of an improved toothbrush design in a variety of dental applications, including
electric toothbrushing, with specially constructed handles, and in a wide variety
of toothbrushing environments including in environments away from home.
[0017] It is a further object of the invention to provide a system for improved dental hygiene
in which an improved head is used which may be readily replaced either with a different
head or with a clean head.
[0018] It is a further object of the invention to provide a toothbrush system wherein an
improved brush head may be detachably attached to a handle to provide various angles
and positions to the head relative to the user's hand grip. For example, one could
turn the brush head on the handle 180° so that either a left- or right-handed user
could get full use of the brush. This enables people with severe minimal dexterity
problems, such as arthritic, elderly or handicapped people, etc. to use the brush
with either their left or right hand.
[0019] It is a further object of the invention to provide a toothbrush with an improved
head to be used with a wide variety of stem holders including manually-operated stem
holders, electrically-operated stem holders, portable stem holders and stem holders
which may be operated either alone by hand manipulation or be attached to an electric
tooth brush handle.
[0020] It is a further object to provide a wedging toothbrush head configuration which is
made more acceptable by decreasing bristle stiffness at those points of primary contact
with the gingival border area of the gums and teeth.
[0021] It is a further object to provide a wedging toothbrush which is more acceptable to
the patient because he can interchange the wedging brushhead with a conventional head.
[0022] Yet a further object of the invention is to provide a toothbrush construction having
bristles shaped, sized, located and flexible for reaching into the interproximal spaces
and under the free gingival margins and which will be particularly adapted for penetrating
those relatively inaccessible areas of the molars and bicuspids from the lingual cavity
and the buccal cavity where the accumulations of the plaque is relatively heavy, and
promoting the desirable rotary brushing motion while enabling the teeth of both the
maxillary and mandibular arches to be brushed simultaneously, while avoiding excessive
abrasion to the teeth and gums.
[0023] In one aspect, this invention contemplates a stem which extends from a handle and
has a leading end section terminating in an attachment means for attaching an elongated
bristle bearing head having a major axis perpendicular to the longitudinal axis of
the stem section. The bristle bearing head is formed as a back having a flat surface
from which a plurality of embedded bristles project in a predetermined arrangement
which is bilaterally symmetrical with respect to the transverse minor axis of the
head. The bristle arrangement, which may be clustered in a plurality of tufts, includes
wedge-like configurations of such tufts having one of the tufts located as an apex
adjacent each opposite end of the back. The length of the head along the major axis
spaces the bristles comprising the apices a distance apart to facilitate penetration
into the interproximal spaces and free gingival margins of the teeth of both the maxillary
and mandibular arches simultaneously when the stem, through handle and manipulation,
is disposed along the occlusal plane with the mouth in an open, teeth brushing, position.
The tuft forming the apex of the wedge-like configuration is centrally located with
respect to the rounded end of the head on the major axis, or, where the ends of the
head are tapered, the tuft forming the apex is located along the trailing or leading
side edges of the head. The slope of the wedge-like configuration away from each apex
conforms to the scalloped contour of the gingival edges thereby improving the ability
of the bristles to penetrate beneath the free margins thereof while improving the
ability of these bristles at the apices to penetrate into the interproximal spaces
at the gumline.
[0024] An area of bristles adjacent the transverse minor axis of the head may be cut to
a shorter length than those bristles located toward the opposite ends of the head
including the bristles in the wedge-like configuration of tufts in order to facilitate
the flexing of the latter in achieving their hereinbefore described intended simultaneous
penetration.
[0025] A modified hourglass shaped head provides additional wedge-like configurations of
bristles and tufts spaced apart along the leading and trailing side edges of the head
between gingival margin penetration when the major axis of the head is held parallel
to the occlusal plane to render an additional capability to the toothbrush which is
particularly useful in cleaning the front teeth.
[0026] Three other styled heads are also provided: a normal rectangle with semi-circled
ends; wedge and reverse wedge configurations; and a gum massaging head.
[0027] The bristles from a frontal view also show a gentle curvature from the center to
approximately the fourth row of bristles. The take-apart attachment means may be designed
as a fraction grip, bolt action, screw action, clip action, 5slide or lock action.
This attachment of head to handle may also be designed so that it can be turned 180°
and then inserted into the handle or vice versa thus reversing the angle of the handle.
[0028] Accordingly, in another aspect, this invention contemplates a toothbrush construction
for improved accessability to the interproximal and free gingival margins of teeth
having at least one head having an hourglass profile and including a wedge-like configuration
having apices at opposite ends, a stem which may be attached and detached from the
head at a location near the narrow portion of the hourglass profile (between the apices),
so that the head can be readily removed and replaced with another head having either
the same hourglass configuration or another configuration. Stems of different varieties
may be substituted for the stems so that the toothbrush may be used with a power toothbrush
handle or in a manually-operated mode.
[0029] In a further aspect of the invention, a toothbrush of the type having an hourglass
configuration with bristles having apices extending from opposite ends of the hourglass
at a stem extending from a center portion of the hourglass was improved by providing
a detachment means for the bristle-bearing head, thereby permitting the changeability
of the head for increased asceptic condition and for the use of a large variety of
heads and stems.
[0030] In a further aspect of the invention, a modular toothbrush system is provided wherein
a large variety of the stems are selectively attachable to a plurality of brush heads.
at least one the heads having an hourglass profile, so that the user may select different
heads in accordance with his different needs and arrange the heads in order to maintain
aseptic conditions when brushing.
[0031] In the accompanying drawings:-
Fig. 1 shows a top view of a preferred embodiment of the invention, using a manually-operated
handle.
Fig. 2 is a side view of the emobdiment shown in Fig. 1.
Fig. 3 shows details of a slide-type head attachment means according to one aspect
of the present invention.
Fig. 4 shows details of a screw-on attachment means according to another aspect of
the present invention.
Fig. 5a and 5b show an alternative embodiment according to the present invention of
a stem and brush head, respectively.
Fig. 6 is an end view showing the brush configuration of the brush head according
to the preferred embodiment.
Fig. 7 shows a brush head having a conventional brushhead configuration for use with
the modular system of the present invention.
Fig. 8 shows a stem according to the present invention which may be either manually
manipulated or used with an electric toothbrush handle.
Fig. 9 shows a package containing a plurality of brush heads in accordance with the
present invention.
Fig. 10 shows an alternate brush pattern for the brush head according to this invention.
Fig. 11 shows a brush head according to the invention having an equal width between
the apices.
[0032] Referring to Figs. 1-3, the basic configuration of the toothbrush construction according
to the invention comprises stem portion 13 to which is attached a brush head 15 and
is removably attached to the stem portion 13, as will be later described. In the preferred
embodiment, the brush head 15 is provided with an hourglass configuration, having
a narrowed portion 17 between two widened portions 19. The stem portion 13 extends
from the narrowed portion 17, thereby forming a more-or-less perpendicular arrangement
between the brush head 15 and the stem 13.
[0033] The stem 13 may be provided with various arrangements to facilitate brushing. In
the embodiment shown, a series of ridges 21 facilitate gripping of the stem 13 near
the brush head 15. The stem 13 is also formed with an offset by bending downward at
a forward bend 23 and back upward at an aft bend 25.
[0034] Referring to Fig. 3, the brush head 15 is provided with an attachment portion 27
which mates with a corresponding attachment portion 29 on the stem 13. These attachment
portions 27, 29 join each other at interface,31.
[0035] It is possible to connect the stem-brush portions with a threaded connection means,
as shown in Fig. 4, where a stem portion 13' has a stud 33 extending into the brush
head >15' at a narrowed portion 17' thereof. The brush head 15' receives the stud
33 by way of a threaded hole 35.
[0036] Referring to Figs. 5a and 5b, a socket connection may be used to connect a stem 13"
with a brush head 15". This arrangement is particularly easy to manufacture out of
plastic. In this embodiment, the brush head 15" has a male extension 37 which is received
by socket 38. A protrusion 39 on the male extension 37 snaps into one of two opposed
holes 40 to retain the brush head 15" in position on the stem 13". By providing opposing
holes 40, the brush head may be placed in two positions 180° apart.
[0037] Referring again to Fig. 3, the method of attaching brush head 15 to stem 13 may also
be by means of snapping. In this case, the materials of the brush head 15, and particularly
the attachment portion 29 of the stem 13 will be made soft and elastic. This would
permit the user to snap brush head 15 into stem 13 without using a sideways sliding
motion.
[0038] Referring to Figs. 1 and 6 in the preferred embodiment, the brush head 15 is formed
with its bristles 41 having two apices 43 extending from the widened portions 19,
and a depressed section 45 extending from the narrowed portion 17. This permits an
improved access to gingival margins and the adjacent tooth surfaces as well as the
interproximal areas, thereby relying upon the construction of the brush rather than
the brushing technique for massage and cleaning in these areas.
[0039] The brush configuration enables an individual user to reach into the interproximal
spaces and free gingival margins. Moreover, this brush enables the user to choose
between cleaning the upper and lower teeth simultaneously, particularly at the back
of the arch or of cleaning the upper and lower teeth separately. In this approach
to brushing, the apices 43 are properly located to enable the user to quickly alternate
between the upper and lower teeth. Thus, the brush enables the user to break up the
bacterial plaque in the interproximal spaces and under the free gingival margins.
By the bacteria being broken up it is inactivated for a twenty-four-hour period, for
the prevention of dental carries and gingival diseases.
[0040] The general shape of the head 15 is that of an hourglass figure, consisting of more
bristles in the widened areas 19, corresponding to the maxillary and mandibular gingival
areas of a patient's teeth.
[0041] In the preferred embodiment of the "average size" head, the widened portions 19 have
a measurement of 14 mm. The narrowed portion 17 of the hourglass has a measurement
of 10mm. The total width of the head 13 is 24 mm. The widened portion 19, corresponding
to the gingival regions, are comprised of three vertical rows of bristle tufts. The
narrowed portion 17 comprised of three vertical rows of bristle tufts also. The width
of the widened portions 19 comprises rows of four tufts each, following the curvature
of the hourglass form. The narrowest portion (i.e. middle portion) is comprised of
rows of three tufts each. The widened portions 19 have a bristle tuft length of 10
mm. The narrowed portion 17 is 8 mm in length.
[0042] In the preferred embodiment of the manually operated toothbrush's stem 13, the overall
length of the lateral plane is 130 mm and exhibits an outline form extending away
from the attachment point 29 for the head 15 running horizontally 50 mm and then flowing
upward, ending at its highest point at approximately 35 mm and continuing at this
35 mm height in a horizontal direction to its ending dimension. This stem 13 may be
offered in stainless steel or plastic.
[0043] Referring to Figs 1 and 4, in order to reduce the abrasive effect of the toothbrush
on the teeth and gums, certain bristles 47 are chosen as primary contact bristles.
These primary contact bristles 47 are at the perimeter of the brishing surface at
the apices 43 and are therefore most likely to contact the surfaces of the teeth and
gums prior to the remainder of the bristles 41. If the stiffness or the modulus of
elasticity of all bristles 41 is the same, then the primary bristles 47 would therefore
be most likely to exert the highest forces on the patient's mouth, thereby causing
the primary contact bristles 47 to exert an abrasive effect which is equivalent to
that of a bristle in the depressed section 45 which is significantly firmer.
[0044] In order to increase the mildness of contact for any given bristle thickness, the
primary contact bristles 47 are made softer than the remaining bristles, as set forth
in the following example:
Example
[0045] A Nylon bristle toothbrush having the "Vee" configuration of Fig. 5 is made with
Nylon bristles, the majority of which has a thickness of .25 mm in order to reduce
the abrasive qualities of these bristles on the area of the free gingival margins,
the primary contact bristles 47 are made with the thickness of 0.20 mm.
[0046] In cases where a patient may be reluctant to completely switch to a new type of brush
head, he is able to obtain a brush head having a conventional design 51 as shown in
Fig. 7. As can be seen, the conventional design brush head 51 is also provided with
a head attachment portion 27 which is identical to the attachment portion 27 of the
preferred hourglass brush head to the attachment portion 27 of the preferred hourglass
brush 15. It can be readily seen that, by providing the identical attachment portion
27 and otherwise providing for proper clearance between the conventional design brush
head 51 and the stem 13, the conventional design brush head 51 may be used with stem
13.
[0047] It can be readily seen that, in addition to our hourglass design brush heads, such
as brush head 15 and conventional design brush heads such as brush head 51, a wide
variety of attachments may be used in accordance with the present invention. For example,
a gum-massaging head (not shown) of the type having rubber bristles may be provided
with this system. Other attachments are also possible, such as flosser attachment
(not shown).
[0048] since the brush head, such as brush heads 15 and 51 may be separated from the stem
13, it is possible to frequently replace with the brush heads 15, 51. By providing
new brush heads 15, 51 at frequent intervals, not only are more expensive designs
of the stem 13 possible, but the user may be assured of the use of a clean brush head
at all times. This permits, not only the use of a preferred design of the brush head,
such as brush head 15 by the patient on a trial basis, but also permits improved cleaning
of the teeth under more sanitary conditions.
[0049] Referring to Fig. 8, a stem 55 is provided for mounting to an electric toothbrush
handle (not shown). Stem 55 has an attachment portion 29 which is identical to the
attachment portion on stem 13. This permits the interchangeability of stems 13, 55
with brush heads 15, 51. Stem 55 is provided with a mating fitting 57 which mounts
to the moving end of the particular toothbrush handle in which stem 55 is designed.
[0050] A serrate recess 59 permits the use of stem 55 at places where the electric toothbrush
head is not available or cannot be plugged into a suitable source of electrical power.
However, it can be readily seen, that by using stem 55, the user does not need to
purchase an entire toothbrush head specifically for the use with the electric toothbrush.
This is important, particularly in cases where the user does not want to, for social
reasons, indicate that an entire toothbrush was purchased for use with another person's
toothbrush handle.
[0051] Referring to Fig. 9, brush heads may be provided in a conventional blister package
61, separately from the stem. In the package 61 shown, two styles of brush heads 15,
63 are shown; however, the bristle construction is specific to a particular choice
of the patient. Indicia 65 of the package indicates that the bristles 41 are of that
specific construction, facilitating selection at point of purchase. Since the brush
heads may be placed on any of a number of stems, the patient is not further limited
by his choice of stems.
[0052] By providing disposable brush heads, the user is able to eliminate the need for carrying
a tube of toothpaste. Particularly during travel, the toothpaste can cause problems
of inconvenience, even where a toothpaste does not leave its tube while it is still
in the user's suitcase. To this end, toothpaste may be provided with the brush heads,
as implied by the indicia 65 in Fig. 9.
[0053] While the invention has been described in terms of these specific embodiments shown,it
is clear that various modifications can be made to the present invention. For example,
the embodiment of Fig. 4 is intended to also be useful with the conventional designed
toothbrush head or with a stem to fit an electric toothbrush.
[0054] As stated above, the preferred interproximal brush head should not be limited to
the configuration of brush head 15 in Figs. 1-4. Referring to Figs. 10-11, wedging
type heads 71, 73 may be constructed with primary contact bristles 47' extending across
four rows in the apices in a variety of tuft patterns, according to convenience of
manufacture. Additionally, referring to Fig. 11, by providing a reduced thickness
for the primary contact bristles 47' at apices 75, intermediate bristles 77 between
the apices may be provided without a narrow tuft configuration. This will still provide
for improved contact with interproximal spaces and gingival areas, as brush heads
71, 73 will have the profile of brush heads 63 (Fig. 9), providing brush heads 71,
73 with a wedging effect.
1. A toothbrush construction having the capability for simultaneously penetrating
the interproximal spaces and the free gingival margins of the teeth of both the maxillary
and the mandibular arches comprising:
a) at least one elongated bristle bearing head having a major axis extending between
opposite ends of said head, said,bristle-bearing head comprising a back having a substantially
flat surface, a plurality of bristles projecting from said flat surface in a predetermined
arrangement bilaterally symmetrical with respect to a minor axis of the head, the
predetermined bristle arrangement including a wedge-like configuration having an apex
located adjacent each of the opposite ends;
b) a means for detachably attaching the head to a stem, the stem having a longitudinal
axis, the attachment being at a leading end of the stem so that when the head is attached
to the stem, the stem's longitudinal axis is coaxial with respect to the minor axis
of the head;
c) a mid'portion of the head located between the apices, the length of the mid portion
along the major axis being such as to position each apex at the gingival margin at
each of the edges when the mouth is at an open position and the stem disposes the
longitudinal apices in the occlusal plane, wherein the head can be readily removed
from the stem and replaced with other heads having either the same configuration or
a different configuration.
2. The toothbrush head of claim l,wherein each head may be selectively attached to
a plurality of stems including to a stem which may be connected to a power toothbrush
handle and to a manually-manipulatable stem.
3. The toothbrush of claim 1 or 2, wherein bristles around the perimeter of the bristle-bearing
head at the apices have a thickness which is less than the average thickness of the
remainder of the bristles in order to reduce the firmness and abrasive qualities of
these bristles.
4. A toothbrush construction of the type having the capability for simultaneously
penetrating the interproximal spaces and the free gingival margins of the teeth of
both the maxillary and mandibular arches comprising a stem extending from a handle,
a leading end section of the stem extending from a handle, a leading end section of
the stem having a longitudinal axis, the leading end section terminating in an elongated
bristle-bearing head having a major axis extending between opposite ends of the head
and perpendicular to the longitudinal axis, the bristle-bearing head comprising a
back having a substantially flat surface, a plurality of bristles projecting from
the flat surface in a predetermined arrangement bilaterally symmetrical with respect
to a minor axis of the head, the stem longitudinal axis being coaxial with the minor
axis, the predetermined bristle arrangement including a wedge-like configuration having
an apex located adjacent each of the opposite ends, the length of the head between
said apices being such as to position each apex at the gingival margin of each of
the arches when the mouth is in an open position and the handle disposes the stem's
longitudinal axis in the occlusal plane, the improvement comprising:
the bristle-bearing head being detachably connected to the leading end section of
the stem, thereby permitting interchangeability of the head with other heads to increase
asceptic condition of the toothbrush and facilitating the use of a large variety of
heads, while also permitting interchangeability of the stem and handle with other
stems and handles.
5. The toothbrush construction of claim 4, further comprising the improvement of providing
bristles along the perimeter of the brush head and the apices and the stiffness which
is less than the stiffness of the remainder of the bristles.
6. A modular toothbrush system comprising:
a) a variety of stems having longitudinal axes including at least one stem which is
detachable to a toothbrush motor and at least one which extends to a handle portion
which must be manually manipulated in a brushing action in order to brush teeth; and,
b) a plurality of brush heads selectively detachable to the stems, at least one of
which brush heads has a major axis extending opposite ends of the head, the brush
head comprising a flat surface, a plurality of bristles projecting from the back surface
in a predetermined arrangement bilaterally symmetrical with respect to a minor axis
of the head, a predetermined bristle arrangement including the wedge-like configuration
having an apex located adjacent each of the opposite ends;
wherein the user may select a stem in accordance with his mouth size and select a
brush in accordance with his brushing requirements and the user may interchange brush
heads in order to maintain aseptic conditions when brushing.
7. The modular toothbrush system of claim 6 wherein the attachment of the brush heads
is by a snap-in connection at the end of the stem.
8. The modular toothbrush system of claim 6, wherein the attachment of the brush heads
is by.a threaded connection 'of the brush head to the stem.
9. The modular toothbrush system of claim 6 wherein the stem further comprises, at
the leading end thereof, a backing plate with the brushing heads being removably attached
to the stem at the backing plate, the attachment of the brush heads onto the stem
being effected by a sliding movement.
10. The features herein described, or their equivalents, in any patentably novel selection.