Note: Descriptions are shown in the official language in which they were submitted.
CA 02383917 2002-03-05
wo omr~ ~.t,~~~
1
A HANDLE FOR A TOOTHBRUSH
Field Of The Invention
The present invention relates to handles for personal care implements, more
especially
for toothbrushes.
Background Of The lnvendon
In order to function effectively, toothbrushes and other such hand held
implements
require to be gripped firmly. However they ofttn require the grip to be
ficquently
changed, such as by rotating the handle within the user's hand, in order, for
example, to
reach different parts of the mouth, to adjust to brushing of diffetcat tooth
surfaces or to
employ varying bnishing orientations as recommended by dental professionals.
Surprisingly, most toothbrushes still have a rather conventional handle which
is typically
rectangular, circular, or rounded rectangular in cross-section, with the cross-
section being
more or less the same shape along the length of the handle, Improvements to
the grip are
generally confined to the inclusion of elastomeric insects. Nevertheless, the
patent
literature documents several attempts to improve upon the basic design.
US 4,780,924 describes an ergonomically designed toothbrush with a shaped
handle
which is comfortable to grasp in numerous ways with either hand. Although the
handle
has a distinctive shape in side view, it is described as being substantially
rectangular in
cross-section throughout its length.
US 5,191,671 descn'bes a toothbrush with a handle having a trapezoidal cross-
section
which both aids is orientation of the bristles in the mouth and provides stren
8~
WO 96101577 describes a toothbmsh with a radial anti-slip st<vcdu~e protruding
from sad
circuanscn'bing the bottom and lateral surFaces ofthe handle. A stated
advantage of this
arrangement is that it does not force gripping at any Predisposed orientation
but allows
for holding the toothbrush in the user's most habitual manner.
WO 97/07706, in the name of CoIgate-Palmolive Company, describes a toothbrush
with
a handle which has an end portion, a shoulder and a waist, the waist being
naaower is
plan view than the end portion or the shoulder. The handle preferably also
comprises
grip-enhancing mats. A stated objective of the handle configurations is the
provision of a
toothbrush which is easier for the user to manipulate. The Applicant also
markets a
corrcaponding brush in Europe under the 'Sensation' name, fiuthcr described on
the
applicant's web site as the 'Wave' toothbn~sh and said to be very comfortable
to hold
and manoeuvre. Although the patent application discloses diffr~nt ratios of
end portion
CA 02383917 2002-03-05
wo omr~z ~t,.r~soo~ls~
2
andlor shoulder to the waist between plan and side views, there is no
disclosure of non-
circular sections having different orientations. The marketed brush has a
substantially
constant shaped cross-section along its length.
WO 99123910, in the name of Crillette Canada Inc., illustrates a toothbrush
con-esponding
to the Oral-B~ Cross-Actions toothbrush which has a grip portion of the handle
having
a rounded rectangular section and a narrower waist portion with an
approximately square
section .
Despite the foregoing, there remains a need for fiuther improvement in the
ergonomics of
handle design for toothbrushes and the like. It has now been found that a
hand3e which is
comfa~table to hold, provides a faro grip and facilitates manipulation,
particularly
rotation, by the user can be provided by arranging for adjacent first and
second grip
portions which have respectively ovoid and elliptical cross-sections having
perpendicular
major axes.
S~marv Of The lnvention
The presciat imrcntion provides a handle for a personal care implement,
especially for a
toothbrush, the handle having distal and proximal ends, the distal end being
connectad to,
or adapted to oonaect to, a grooming head. The handle comprises:
a) a first grip portion, adjacent the proximal end of the handle, for holding
in the
user's hand, the first grip portion having an ovoid cross-section which has a
major
axis and a minor axis; and
b) a second grip portion, for manipulation by the user's fingers exten from
the
first grip portion in the direction of the distal end of the handle, and
having, at least
in a region adjacent the first grip portion, an elliptical cross-section which
has a
major axis and a minor axis;
characterised in that the major axis of the second grip portion is
peapeodicular to the
maj or axis of the first grip portion.
An implement with a handle as described herein is comfortable to hold and easy
to adjust
within the hand. It is particularly suited for the manipulations required of a
toothbrush
but it is envisaged that it world also be suitable for similar personal care
implements
such as razors, hairbrushes, tongue scrapers and the like.
~et~ilod Description of the Invention
CA 02383917 2002-03-05
wo omr~n
3
The longitudinal axis of the handle is that which extends between the distal
and proximal
ends thereof. Other references to longitudinal should be taken to refea to
directions slang
or parallel to the longitudinal axis unless specified otherwise.
lJnless specified otherwise, handle cross-sections referenced herein should be
taken
perpendicular to the longitudinal axis of the handle.
Major axes refer to the longest dimensions of the cross-sections to which they
refer.
Minor axes refer to the longest dimensions of the same cross-sections drawn
perpendicular to the major axes. A minor axis will always be shorter than the
corresponding major axis,
By "ovoid" is meant a 2-dimensional figure approximately Gornsponding to the
typical
lengthwise cross-section of an egg, that is a generally rounded figure having
one end
which is more pointed than the other. It includes, for example, figures which
may have
partially flattened portions provided that the overall ovoid impression is
retained.
Handle
The handle of the invention has distal and proximal ends. The distal end is
connected to,
or is adapted to connect to, a grooming head. That is, the grooming hsad is
integrally
formed with or can be datachably connected to the handle, for example to
permit
replacement of a worn head or to allow substitution of a different type of
head, such as a
gum massager, tongue s«aper, tooth pick, compact brush or interdental brush
for a
regular brush head. The form of the head is not critical to the invention,
although a
correlation between the shape of the head and the first grip portion of the
handle can
provide additional benefits as discussed below.
In a prefernd embodiment the handle has a head integrally moulded with it, the
head
bearing bristles or being subsequently fitted with bristles, such that it
foams a toothbrush.
The head, extruding bristles and massaging elements, can lx of single
constnution or it
can be mufti-segmcated as set out in WQ-A-98127846, incorporated herein by
reference.
Prefrrably it is of single ca~nsrruction. In a further particularly preferred
embodiraeart the
head co~rises both bristles and massaging elements as disclosed in co-pending
application 99GB-013717, incorporated herein by reference in its entirety. In
the
preferred embodiment the distal end of the handle has a primly grooming head
integrally or releasably attached thea~cto, wherein the grooming head has
bristles
attending therefrom in a direction generally parallel to the major axis of the
first grip
portion and most preferably in the direction drawn towards the more pointed
end of the
ovoid cross-section,
CA 02383917 2002-03-05
wo mnr~s
4
The handle herein comprises at least first and second grip Portions. The first
grip
Portion, adjacent the proximal end of the handle, is for holding in the palm
of the user's
hand. It has ~ ovoid cross-section which has a major axis and a minor axis.
The Fret
grip portion has a longitudinal length of from about 50 to about I00 nvn,
preferably fiom
about 60 to about 90 mm. In order to achieve a smooth transition into the
second grip
portion of the handle, the cross-section of the first grip portion may not be
ovoid along its
entire length but typically it will be ovoid along 50~/0 or more, preferably
65% or more of
its length. The ovoid cross-section has a major axis and a minor axis which
ace generally
in the ratio of from 1.4:I to L1:1, preferably in the ratio of fiom 1.3:1 to
1.1:1, and more
preferably from 1.2:1 to 1.1:1. Again the precise values of the ratio may vary
along the
length of the fast grip portion but this will generally be true along 50~/0 or
more,
preferably 65% or more of its length. The first grip portion has a top surface
which, in
side profile, is preferably arcuate to provide a more comfortable grip. The
proximal end
of the first grip portion is also preferably rounded for the same reason. A
bottom surface
of the 5rst grip portion, opposed to the top surface thereof, is preferably
flattened along
at least part of its length so that the handle can rest in a stable position
when placed on a
flat surface, for example in order to avoid bristle contact with the surface.
The maximum
value of the major axis of the first grip portion, at about 40% to b0% along
its
longitudinal axis , is preferably in the range from about 15 to about 20 mm,
mare
preferably fiom about 16.5 to about I9 mm. The maximum value of the minor axis
of
~ ~ 8nP P~u~ ~~Y ~u~8 ~ hut the same longitudinal position as that
of the major axis, is generally in the range from about 11.5 to about I7 mm,
preferably in
the range from about 13 to about I7 mm, more preferably from about 14 to about
16 mm.
In an espocially preferred embodiment the first grip Portion is entirely
coated with
elastomer, this makes it comfortable to hold and allows greater flexibility in
providing a
disrinctive appearance. The elastomer coating comrprises part of the first
grip portion and
should be included in any dimensional analysis thereof. In order to reduce the
friction
between the brush and machinery parts during manufacturing, a 'stripe' of
plastic can
optionally be allowod to pratiude through the elastomer at parts where the
handle
co~acts guide chapels when the handle is conveyed from one manufacturing
station to
another. Generally the 5rst grip portion will be a~n integral part of the
handle. ~ It is also
envisaged however that at least an outer part of the first grip portion could
be removable,
preferably with a scoop on/off or friction fit, in order to conceal a storage
area for a
removable head; auxiliary ding heads which can optionally be permanently
attached
or releasably attachod to the proximal end of the handle; auxiliary materials
such as
toothpaste, other cleaning materials or diagnostic elements; or merely a
thi~er skeleton
CA 02383917 2002-03-05
wo om~~z ~.,USOOVts~a
which more easily fits into a conventional toothbrush holder. Alternatively,
or
additionally a removable first grip portion, or outer part thereof, can be
adapted to
provide a cap which can fit over the head which is attached to the distal end
of the
handle. In this way the whole implement can be adapted to occupy a smaller
space when
not being used and/or the head can be kept clean, malting it particularly
suited for travel
usage. Suitable auxiliary grooming heads herein include, but are not limited
to a gum
massager, tongue scraper, tooth pick, compact brush or interdeatal brush.
The socond grip portion of the handle extends from the first grip portion in
the direction
of the distal end of the handle. It is particularly for manipulation by the
user's fingers
and has, at least in a region adjacent the first grip portion, an elliptical
cross-section
having major and minor axes. The second grip portion typically has a
longitudinal length
of from about 20 to about 45 mm, preferably from about 25 to about 35 mm.
Suitably
the cross-section of the second grip portion is elliptical along 70% or more,
preferably
90~/0 or more of its length. The elliptical cross-section has a major axis and
a minor aids
which are preferably in the ratio of firm 1.3:1 to 1.1:1, preferably from
1.2;1 to 1.t:1.
Again the precise values of the ratio may vary along the length of the second
grip portion
but this will generally be true along 70% or more, pr~efexably 90% or more of
its length.
The maximum value of the major axis of the second grip portion is preferably
in the
range from about 8 to about 14 mm, more preferably from about 10 to about 12
mm. The
maximum value of the minor axis of the second grip portion is preferably in
the range
from about 8 to about 10 mm.
The major axis of the second grip portion is perpendicular to the major axis
of the first
grip portion
The minor axis of the aa:ond grip portion extends behveen top and bottom
surfaces
thereof. In preferred embodiments at least one of the top and bottom surfaces,
preferably
both, has gripping ridges thereon. These are preferably formed from an
clastomer and
can readily be incorporated using conventions! moulding techniques. The
ridges, which
preferably extend in a transverse direction along the surface(s), do not
generally project
from the surfaces) by more than about 1 mm and may also extend amend the sides
of the
second grip portion. In measvaing or calculafing dimensions or ratios of the
second grip
portion any ridges present should be ~celuded.
In prefemcd embodiments herein the handle fzuther comprises a third grip
portion distal
the second grip portion, the bird grip portion being both wider and deeper
than the
saond grip portion. The third grip Portion can act as a thumb stop and is
preferably
CA 02383917 2002-03-05
WO Ol/I'139~ pL~t/USOW15~4
6
coated with au elastamer. The third grip portion can coraprise a means for
releasably
attaching a head and/or neck to the handle.
The handle may further compaxse a neck region at its proximal end, the neck
region being
generally of smaller cross-section than the rest of the handle and usually
devoid of grip
elemeats.
The bulk of the beadle (and head where appmpaiate) is g~raIly made of
relatively non
compn~ible materials, preferably with a modules of elasticity of at least
about 500 MPs,
more preferably at least about 1000 MPs, which are conventional in tire
manufachu~e of
toothbrushes, especially plastics materials. Suitable plastics materials
include, for
example, polyamides, polypropylenes, polyurethanes, poly(methylmethacrylates),
and
cellulose acetate propionates. Polypropylene is preferred. Suitable
polypropylenes
include 'Polypropylene Molten 52945' (marketed by Schulman), having a modules
of
elasticity (ISO 178) of 1500 MPs and Apryl 3400 MAl from Elf Atochem.
The handle (aad head where appropriate) is typically made by injxtion
moulding.
Bristles and massaging elements can be attached to the head by art known
methods such
as stapling and anchorless manufacturing technologies.
Elastomeric portions of the handle herein are preferably made of a
thermoplastic
elastomer having a hardness fmm about 10 to about 90 Shore A, more preferably
from
about 50 to about 80 Shore A and most preferably about 70 Shore A. Suitable
materials
include those available under the tradenames Mcgol, S~toprtne and Multibase.
Silicone
elastomers arc also useful. Preferably the handle comprise a unitarily moulded
skeleton
onto which the elastomer areas are moulded in - a separate injation moulding
step.
Preferably all the elastomer areas are intemannected to allow singl-pint
inja;ion
moulding.
Brief Descr~nion 4f They
While the specification concludes with claims particularly poring out aad
distinctly
claiming the subject inventiarn, it is believed the same will be better
understood from the
following description taken in conjunction with the accompanying drawings in
which:
Figure I is a perspxtive view of an embodiment of a handle of the present
invention.
Figure 2 is a top view of Figure 1.
Figure 3 is a bottom view of F'~re 1.
Figure 4 is a side view of Figure 1.
Figure 5 is a cross-section through the socond grip portion at S-S.
CA 02383917 2002-03-05
wo omr.~
7
Figure 6 is a cross-section through the first grip portion at F-F.
Figure 7 is a side view of a second esnbodimmt of a handle of the present
invention.
Detailed Description Of The Dra~ari;nas
Referring now to the drawings in detail wherein like numerals indicate the
same element
throughout the views there is shown in Figures I to 6 a handle according to
the invention
generally indicated as 1. The handle comprises first, second and third grip
Portions
indicated r~pxtively as 2, 3 and 4. The handle feather comprises a slim neck 5
and has
a head 6 integrally attached to distal end of the handle 1. 1n the preferred
emhodim~t
the head 6 has bristles Wctending from the upper face of the head G, these are
not shown
however. In this embodiment the head, neck and second grip~portion are all
part of eon
unitarily formed polypropylene skeleton which extends the entire length of the
brush.
First and third grip portions, 2 and 4, have an outer coating of elastomntr.
The second
grip Portion finther comprises grippiu,g edges 7 which extend transversely
across and
prroject from the upper and lower stufl~. A channel 8 running longitudinally
along the
handle connects the various elastomaic areas so that they can be manufactw~od
by single_
point injection moulding.
The 5rgt grip portion 2 has an ovoid croea~ection, as best seo~n in Figure 6.
A fled
portion 9 on the lower surface of the first grip portion allows the handle to
rest in a stable
position on a flat surfacx with bristle-bearing face of head 6 uppermost.
Viewed in side
profile, as in Figure 4, the first grip portion has an arcuate upper au~rfa~ce
along the
longitudinal direction. The proximal end IO of the handle is munded. As
described
above, the first grip portion can be detaclu4ble from the main body of the
handle.
The second grip Portion 3 has an elliptical cross-section, as best seen in
Figure 5. Its
major and minor axes, 11 and I2, are perpendicular to the major and minor
axes, 13 and
14, of the fast grip portion.
This embodiment comprises a third grip Portion 4 which can act as a rest for
the nser's
thumb sad has a flat landing area 15 for that purpose.
In Figure 7, a second embodiment of the handle is shown in which portions 1b
of the
polypropylene part of the brush handle protrude through the elastomer coating
of the ~trst
and third grip portions both slang the sides of the handle and at its proximal
end. The
exposed polypropylene portions assist in the smooth ruamag of the handle along
menufacriuing production lines.
