AU722959B3 - Toothbrush - Google Patents

Description

Regulation 3.2

AUSTRALIA

Patents Act 1952 PETTY PATENT SPECIFICATION

(ORIGINAL)

Name of Applicant: Actual Inventor: Address for Service: Invention Title: SmithKline Beecham Consumer Healthcare GmbH Hermannstrasse 7, D-77815 Buhl, Germany Hans HALM DAVIES COLLISON CAVE, Patent Attorneys, 1 Little Collins Street, Melbourne, 3000.

Toothbrush The following statement is a full description of this invention, including the best method of performing it known to us: -1- P:\OPERNDHN1309G-9?.DIV 23/3/00 -2-

TOOTHBRUSH

This invention relates to toothbrushes of the type having a flexible link between their head and their handle.

Toothbrushes generally consist of a head, from a bristle face of which extend bristles, integrally linked at the base end of the head to the head end of a grip handle, with a neck region between the head and the grip handle, the head, handle and neck being disposed longitudinally.

Toothbrushes are known having a flexible link between the head and the neck region, e.g. in PCT/EP92/00645. Such toothbrushes are two component toothbrushes comprised of plastics and elastomeric materials, and one such toothbrush is the known Aquafresh Flex 'n Direct T M toothbrush marketed by SmithKline Beecham plc, with a composite plastics materialelastomeric material link between the base end of its head and the immediately adjacent part of its neck. In the Aquafresh Flex 'n Direct TM toothbrush the said link uses a relatively long thin spine to cross a chasm of a complex multiple convex-concave curved shape in the toothbrush. It is an object of the present invention to provide an improved type of flexible link between the head and handle of a toothbrush.

According to this invention, there is provided toothbrush which comprises a head, from a bristle 'face of which extend bristles, integrally linked at the base end of the head to the head end of a grip handle, with a neck region between the head and the grip handle, all being disposed along a longitudinal axis and having a width direction perpendicular to the longitudinal direction, and made integrally of plastics material, wherein the head has a base end which is adjacent to the neck region, the base end of the head and the neck region having surfaces which face each other along the longitudinal direction to define longitudinally between them a widthways aligned slot in the plastics material of the toothbrush and the head being integrally connected to the neck at the base end of the head by an integral thinned part which is located immediately longitudinally adjacent to the base end of the head and is integrally connected to and extends longitudinally between the said surfaces to bridge the slot, the thinned part being of thinned cross section relative to the longitudinally adjacent parts of the neck region and the base end of the head to which it is connected, the said thinned part being laterally surrounded by a mass of elastomeric material bonded to the plastics material, P:\OPER\DH\I3090-9).DIV 235100 -3the mass being of a shape which bulges laterally beyond the line of the surface of the longitudinally adjacent parts of the neck region or the base end of the head to which it is connected.

Preferably, the thinned part is in the form of a spine of the plastics material extending longitudinally between the said surfaces, and this spine has a length:width ratio in the range 2:1 to 1:2.

Preferably, the surface of the base end of the head to which the end of the thinned part closest to the head is connected is of a concave shape as viewed in plan, to the deepest part of which the thinned part is connected.

Preferably, the surface of the base end of the head to which the end of the thinned part closest to the head is connected is of a concave shape as viewed in plan, to the deepest part of which the thinned part is connected, and the surface of the neck region to which the end of the thinned part closest to the handle is connected is also of a concave shape of opposite curvature, so as to form a rounded cavity bounded in part at its longitudinal ends by these two respective concave surfaces.

Preferably, the surfaces of the base end of the head and the neck region which face each other along the longitudinal direction follow a crescentic curve which is substantially part circular over all of its length with the cusps of the crescent pointing generally toward the handle end of the toothbrush to define longitudinally between them a widthways aligned curved sided slot and the thinned part bridges this slot.

Preferably, the surfaces of the base end of the head and the neck region which face each other along the longitudinal direction define longitudinally between them a widthways aligned parallel sided slot and the thinned part bridges this slot.

Preferably, as viewed from the side, the said surfaces of the base end of the head and the neck region which face each other along the longitudinal direction are aligned at a nonperpendicular angle to the longitudinal toothbrush axis.

Preferably, the said surfaces are inclined at an angle such that their extrapolation converges on the bristle surface side of the toothbrush.

Preferably, the thinned part bridges the longitudinally adjacent surfaces of the neck region and the base end of the head nearer to one or other of the bristle face or the reverse P:\OPER\DH\13090-97.DIV 2353I( -4face of the toothbrush.

Preferably, the cross section of the thinned part is 0.1 0.75 of the cross section of the immediately longitudinally adjacent parts of the toothbrush.

Preferably, the mass of elastomeric material is a rounded mass.

Preferably, the mass bulges laterally, in the direction perpendicular to the longitudinal axis of the toothbrush and generally in the bristle direction, to between about 1.5 to 4 times the thickness of the immediately adjacent part of the neck and/or the base end of the head.

Preferably, the said surfaces which face each other along the longitudinal direction follow a crescentic curve which is substantially part circular over all of its length with the cusps of the crescent pointing generally toward the handle end of the toothbrush to define between them a widthways aligned curved sided slot in the plastics material of the toothbrush, the said surfaces are connected to each other by an integral thinned part which is located immediately longitudinally adjacent to the base end of the head and is integrally connected to and extends longitudinally between the said surfaces to bridge the slot, and which is of thinned cross section relative to the longitudinally adjacent parts of the neck region and the base end of the head to which it is connected, and which is in the form of a spine of the plastics material extending longitudinally between the said surfaces, the spine having a length:width ratio in the range 2:1 to 1:2, the cross section of the thinned part being 0.1-0.75 of the cross section of the immediately longitudinally adjacent parts of the toothbrush; the thinned part being laterally surrounded by a rounded mass of elastomeric material bonded to the plastics material, the mass being of a shape which bulges laterally beyond the line of the surface of the longitudinally adjacent parts of the neck region or the base end of the head to which it is connected.

Preferably, the surfaces of the base end of the head and the neck region which face each other along the longitudinal direction are aligned at a non-perpendicular angle to the longitudinal toothbrush axis.

Preferably, the thinned part bridges the longitudinally adjacent parts of the neck region and the base end of the head nearer to one or other of the bristle face or the reverse face of the toothbrush.

P:\OPER\DH\13O9O91.DIV -23/3/00 The other parts of the toothbrush may be of essentially conventional construction.

Alternatively the neck and handle parts of the toothbrush may for example include flexibility modifying features such as the shaped folds disclosed in EP 0336641 A, the contents of which are included herein by way of reference. For example the handle may include, as an integral part thereof, a resiliently flexible portion comprised of at least one or "U" shaped fold formed integrally with the remainder of the handle and in a plane from 300 to 1500 to that in which the handle lies. A longitudinal structural rib may be provided across such folds. The above-described link between the base head of the head and the neck of the toothbrush, when used in a toothbrush having such a resiliently flexible portion, is found to be particularly advantageous.

The plastics material and elastomeric material used in the construction of the toothbrush may be known conventional plastics and elastomeric materials as disclosed for example in EP 0336641 A, or as used in the construction of the above-mentioned Aquafresh Flex 'n Direct T M toothbrush. The toothbrush of the invention may be made by conventional injection moulding processes in which the plastics material parts are injection moulded first, and the elastomeric material is then moulded around the hot plastics material in such a way that the two bond by fusion together.

The invention will now be described by way of example only with reference to the accompanying drawings which show: Figs. 1, 2 and 3 show respectively a plan, underside and longitudinal section of the head-neck region of one embodiment of a toothbrush of this invention, without the mass of elastomer being in place.

Figs. 4, 5 and 6 show respectively a plan, underside and side view of the head-neck region of another embodiment of a toothbrush of this invention without the mass of elastomer being in place.

In Figs. 3 and 6 which show views of the head 1 from the side from a direction perpendicular to the longitudinal axis and the bristle direction) the thinned part 10 is closer to the bristle face 2 than to the reverse face 14 of the head 1. The connection between the thinned part 10 and the base end 4 of the head 1 is entirely or substantially in the part of the base end 4 of the head 1 which, in terms of the thickness of the head 1, is in the half P:\OPER\DH 3090-97. DIV 23/3/00 -6nearer to the bristle face 2 of the head.

Figs. 7, 8 and 9 show respectively a plan, underside and side view of the head-neck region of a-toothbrush of this invention with the mass of elastomer being in place.

Figs. 10, 11, 12 and 13 show alternative embodiments of the toothbrush of this invention.

Referring to Figs. 1, 2, 3, 7, 8 and 9 a toothbrush head 1 is shown, from a bristle face 2 of which extend tufts of bristles (not shown). The bristles are mounted in socket holes 3 (not all shown in Fig. 3) which correspond to the pattern of the bristles. The head 1 is integrally linked at its base end 4 to the head end 5 of a grip handle 6, with a neck region 7 between the head 1 and the grip handle 6, all being disposed along a longitudinal axis A-A and made integrally of plastics material. The grip handle 6 is provided with a grip mat 8 made of elastomeric material, and between the handle 6 and neck 7 is, as an integral part thereof, a resiliently flexible portion 9 comprised of at least one or shaped fold formed integrally with the remainder of the handle and in a plane from 300 to 150 to that in which the handle lies.

In the neck region 7 there is an integral thinned part 10 connected at one of its ends (the "neck end") to the head end 11 of the neck and at the other of its ends (the "head end") to the base end 4 of the head. The part 10 is of thinned cross section relative to the longitudinally adjacent parts 11, 4 of the neck 7 and the head 1 to which it is connected. The thinned part 10 is of circular cross section about its longitudinal axis direction. As shown in Figs. 7, 8 and 9 the part 10 is laterally surrounded by a mass 12 of elastomeric material, which is bonded to the plastics material, and is of a shape which bulges laterally beyond the line of the surface of the longitudinally adjacent parts 11, 4 of the neck 7 and the head 1 to which it is connected.

The part 10 is located at the base 4 of the head 1, and links the head 1 to the neck 7.

The part 10 is in the form of a thin spine of the plastics material extending longitudinally between the said longitudinally adjacent parts 11, 4 of the toothbrush. The spine 10 is of a relatively short stubby shape with length:width dimensions ca. 1.2:1.

In Figs. 1, 2 and 3 the part 4 of the head 1 to which the head end of the part 10 is connected has a surface substantially perpendicular to the longitudinal axis A-A, and the part P:\OPERDH\13090-97.DIV 23/3/00 -7- 11 of the neck 7 to which the handle end of the part 10 is connected also has a surface substantially perpendicular to the longitudinal axis A-A.

In Figs. 4, 5 and 6 the part 4 of the head 1 to which the head end of the part 10 is connected is of a concave shape, to the deepest part of which the thinned part is connected, and the part 11 of the neck 7 to which the handle end of the part 10 is connected is of a corresponding convex shape, forming a curve in which the facing surfaces follow a crescentic curve which is substantially part circular over substantially all its length, with the cusps of the crescent pointing generally toward the handle end of the toothbrush.

In the constructions shown in the Figures the part 10 in effect bridges a chasm 13 between the head 1, at its base 4, and the head end 11 of the neck 7 of the toothbrush. The chasm 13 is in effect therefore a parallel sided slot in Figs. 1, 2 and 3, and a curved slot in Figs. 4, 5 and 6. The part 10 bridges the chasm nearer to the bristle face 2 of the toothbrush than to the reverse face 14.

In Figs. 1 to 6, as viewed from the side from a direction perpendicular to the longitudinal axis and the bristle direction), the surfaces of the chasm 13 between the head end 11 of the neck and the base end 4 of the head 1 are inclined at an angle such that their extrapolation converges on the bristle surface 2 side of the toothbrush.

As shown in Figs. 7, 8 and 9, the mass 12 of elastomeric material is a rounded mass having a spherical symmetry. In Figs. 1, 2 and 3 the parts 4, 11 of the toothbrush longitudinally adjacent to the mass the plastics material is enlarged into a mass 15 of a hemispherical shape similar to that of the mass of elastomeric material 12, and around which the mass 12 of elastomeric material is formed.

Figs. 1, 2, 3, 4, 5 and 6 show preferred embodiments of the invention in which the part 10 links the head 1 to the neck 7, and is in the form of a longitudinal spine, in Figs. 4, 5 and 6 bridging a curved chasm 13 with its concave side adjacent to the head, in Figs. 1, 2 and 3 bridging a substantially parallel sided transverse chasm 13 between the head 1 and the neck 7, the spine 10 being closer to the bristle face 2 than to the reverse face 14 of the head 1, and the mass 12 of elastomeric material is of spherical symmetry.

The plastics material and elastomeric material used in the construction of the toothbrush are know conventional materials as disclosed for example in EP 0336641 A. The P:\OPER\DH\ 13090-97.DIV -23/3/00 -8toothbrush of the invention has been made by conventional injection moulding processes in which the plastics material.parts 1, 6, 7, 10 are injection moulded first, and the elastomeric material is then moulded around the hot plastics material in a known manner such a :way that the plastics material and the elastomeric material bond by fusion together to form the elastomeric material grip mat 8 and the mass 12. In the toothbrush shown in the Figures, two injection points may be necessary to inject the elastomeric material to form the grip mat 8 and the mass 12, although they could be connected by a flow channel to allow use of a single injection point.

Referring to Figs. 10, 11, 12 and 13 toothbrushes are shown of similar construction to those of Figs. 1-9 above, and corresponding parts are numbered correspondingly.

In the toothbrushes of Figs. 10-13 the part 10 is. of a rectangular cross section, with its long axis perpendicular to the direction B of the bristles 15 in Figs. 10 and 11, and parallel to the bristle direction in Figs. 12 and 13. In Figs. 10, 11, 12 and 13 the part 4 of the head 1 to which the head end of the part 10 is connected is of a concave shape, to the deepest part of which the thinned part is connected, and the part 11 of the neck 7 to which the handle end of the part 10 is connected is also of a concave shape of opposite curvature to form a rounded cavity. The mass 12 of elastomeric material is of spherical shape.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

Claims (3)

1. A toothbrush which comprises a head, from a bristle face of which extend bristles, integrally linked at the base end of the head to the head end of a grip handle, with a neck region between the head and the grip handle, all being disposed along a longitudinal axis and having a width direction perpendicular to the longitudinal direction, and made integrally of plastics material, wherein the head has a base end which is adjacent to the neck region, the base end of the head and the neck region having surfaces which face each other along the longitudinal direction to define longitudinally between them a widthways aligned slot in the plastics material of the toothbrush and the head being integrally connected to the neck at the base end of the head by an integral thinned part which is located immediately longitudinally adjacent to the base end of the head and is integrally connected to and extends longitudinally between the said surfaces to bridge the slot, the thinned part being of thinned cross section relative to the longitudinally adjacent parts of the neck region and the base end of the head to which it is connected, the said thinned part being laterally surrounded by a mass of elastomeric material bonded to the plastics material, the mass being of a shape which bulges laterally beyond the line of the surface of the longitudinally adjacent parts of the neck region or the base end of the head to which it is connected.

2. A toothbrush according to claim 1 wherein the thinned part is in the form of a spine of the plastics material extending longitudinally between the said surfaces, and this spine has a length:width ratio in the range 2:1 to 1:2.

3. A toothbrush according to claim 1 or 2 wherein said surfaces which face each other along the longitudinal direction follow a crescentic curve which is substantially part circular over all of its length with the cusps of the crescent pointing generally toward the handle end of the toothbrush to define between them a widthways aligned curved sided slot in the plastics material of the toothbrush, the said surfaces are connected to each other by an integral thinned part which is located immediately longitudinally adjacent to the base end of the head and is integrally connected to and extends longitudinally between the said surfaces to bridge the slot, and which is of thinned cross section relative to the longitudinally adjacent parts of the neck 4Qregion and the base end of the head to which it is connected, and which is in the form of a P:\OPER\DH\22567-00.SPI 20/4/00 spine of the plastics material extending longitudinally between the said surfaces, the spine having a length:width ratio in the range 2:1 to 1:2, the cross section of the thinned part being 0.1-0.75 -of the cross section of the immediately longitudinally adjacent parts of the toothbrush; the thinned part being laterally surrounded by a rounded mass of elastomeric material bonded to the plastics material, the mass being of a shape which bulges laterally beyond the line of the surface of the longitudinally adjacent parts of the neck region or the base end of the head to which it is connected. DATED this SEVENTEENTH day of MARCH 2000 SmithKline Beecham Consumer Healthcare GmbH By DAVIES COLLISON CAVE Patent Attorneys for the Applicants