AU766382B2 - A toothbrush - Google Patents

Description

AUSTRALIA

Patents Act 1990 Colgate-Palmolive Company

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT 4 4 Invention Title: A toothbrush The following statement is a full description of this invention including the best method of performing it known to us:- A TOOTHBRUSH BACKGROUND OF THE INVENTION This invention relates to a toothbrush and more particularly to a toothbrush construction wherein the head and handle each include an elastomeric material, with the two elastomeric materials being of a different composition.

Prior toothbrush constructions include toothbrush heads having pivoted or articulated sections joined together in a variety of constructions, such as a resilient strip of metal or the like, and also include pivoted or hinged articulated sections to provide a curved bristle configuration.

A curved/angled bristle surface configuration offers improved access to :hard-to-reach areas such as the lingual surfaces of the front teeth, and behind the rear molars, placing more bristles in contact with the outer surfaces of the front teeth.

Many current brushes which have rigidly mounted bristles and a rigid curved/angled bristle surface exhibit an inherent disadvantage when brushing both flat as well as concave tooth surfaces. Placing a curved/angled bristle surface on flat tooth surfaces results in fewer bristles making contact with the teeth. These fewer bristles must support the brushing forces applied through the handle, which will result in premature splaying of the bristles.

Some current toothbrushes have a "power tip" configuration (elongated rigidly mounted tip bristles) which are claimed to have improved access 25 benefits.

SUMMARY OF THE INVENTION In a first aspect, the present invention provides a toothbrush comprising a head and a handle, the head having an area comprising a first elastomeric material, the handle having an area comprising a second elastomeric material, the first elastomeric material and second elastomeric material being different elastomeric materials.

In a preferred embodiment, the first and second elastomeric materials have different Shore hardness values. More preferably, the first elastomeric material is softer than the second elastomeric material.

In a further preferred embodiment, the head is articulated and the first elastomeric material comprises a flex area between the two head sections, said first elastomeric material positioned between facing ends of said two head sections. Preferably, each of the two head sections has a lower surface from which bristles extend, said lower surface enclosing an angle in an unstressed state. It is also preferred that the two head sections are connected by a thin bridge, the thin bridge being surrounded by the first elastomeric material between the two head sections.

In a second aspect, the present invention provides a method for producing a toothbrush comprising a head area and a handle area, the method comprising introducing a first elastomeric material in the head area and introducing a second elastomeric material in the handle area, wherein the first elastomeric material is different from the second elastomeric material.

15 In a further embodiment the present invention comprises an articulated toothbrush head defined by two head sections joined by one or more thin bridges of the same resin from which the toothbrush is formed, as by moulding, to produce an integral construction. These thin bridges permit limited flexing between the two head sections, the two sections normally being at a small angle with respect to each other. That portion of the head between the two head sections may be, in one embodiment, in the general form of a T shaped slot running transversely of the top surface of the head, from one side head side edge to another. The slot is filled, as by injection, with an elastomer to control and enhance flexing. The construction is such that the head section most remote from the handle is normally tilted with respect to the head section nearest the handle, the latter head section located at one end of the handle. In a second embodiment, the head section may assume the form of a narrow cylindrical portion, or in a third embodiment two thin bridges may be employed, both having elastomer.

The cross section of the first elastomer may be convoluted, with one or more convolutes. To aid in fixing the first elastomer to the toothbrush head sections, the elastomer may be configured to fit into one or more slots at both ends of the flexing area.

To minimize the gap between bristle tufts when the head is flexed into a flat configuration, it is desirable to position the plastic (resin) bridge between the tip and handle portions as near the bristle tips as possible. This bridge is straightened during flexing, and directly controls the gap between bristle tufts on each side of the flex area.

The elastomeric material of this invention used in the flex area of the head is different to the elastomeric material in the handle area. Therefore, an elastomeric material in the head which allows flexing under the loads typically encountered during brushing and an elastomeric material in the handle which is suitable for use as a grip would be desirable.

Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a side elevational view illustrating the toothbrush head of this invention according to an embodiment of the present invention.

Figure 2 is a top plan view of the toothbrush head shown at Figure 1.

Figure 3 is an elevational view showing the head and tufts of bristles as brushing the inside surfaces of the lower teeth.

Figure 4 is a view similar to Figure 1 and shows another embodiment.

Figure 5 is a view similar to Figure 1 and shows another embodiment.

Figure 6 is a side elevational view of another embodiment.

Figure 7 is a side elevational view of another embodiment.

Figure 8 is a side elevational view of another embodiment.

25 DETAILED DESCRIPTION OF THE INVENTION Referring now to Figure 1, a side elevational view of a toothbrush embodying some of the features and construction of this invention is shown in a vertical position, with a portion of the handle designated at 12. While not completely shown, the reader will understand that the handle extends downwardly and has a longitudinal axis. That 30 portion of the head nearest the handle is designated as section 14 and is collinear with the handle, while that portion of the head most remote from the handle is designated as section 16. An elastomer section or joint between facing ends of sections 14 and 16 is denoted generally as 18. A plurality of tufts of bristles 20 extends at right angles to section 14, while a similar plurality of tufts of bristles 22 extends at right angles from section 16. Tufts of bristles 22 are thus at right angles to lower surface 24 of head m:\specifications\090000\92000\92439h25.doc section 16, while tufts of bristles 20 are perpendicular to lower or bottom surface 26 of head section 14.

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m:\specifications\090000\92000\92439h25.doc A generally T-shaped groove, in longitudinal cross section, extends transversely across the upper or top surface of the head and is thus located between sections 14 and 16. The bottom of the central or main part of the groove is spaced from the lower surface of the composite head, leaving a thickness or bridge section designated as 30 which joins the lower portions of the two head sections. Bridge or zone 30 is typically of a thickness between 0.05 and 0.1cm. The handle and head sections are molded from a plastic or resin such as polypropylene. The generally T-shaped groove is filled with a resilient and soft thermoplastic elastomer. The T groove has to symmetrical wing portions 32, each terminating in an enlarged portion 34, the latter extending towards respective groups of tufts of bristles. The middle of the T shaped resin insert section 18 includes an integral ridge 36, while the lower portion or base portion of the T section is designated as 38. The thermoplastic elastomer which forms section 18 or the elastomer of the 15 handle may be a thermoplastic vulcanate (TPV) consisting of a mixture of polypropylene and EPDM (ethylene propylene diene monomers) which is available as Santoprene (brand), described in US patent 5,393,796 issued to Halberstadt et al, or Vyram (brand), another TPV consisting of a mixture of 2. polypropylene and natural rubber, both Santoprene and Vyram (brands) being elastomers marketed by Advanced Elastomer Systems. Other suitable elastomers include Kraton, a brand of styrene block copolymer (SBC) marketed by Shell, and Dynaflex G 2706 (brand), a thermoplastic elastomer marketed by GLS Corporation and which is made with Kraton (brand) polymer. These and other suitable elastomers have, typically, a Shore A hardness of from about 13 to 94, with about 29 being a preferred hardness for the elastomer of the head. Grooves 40, on the top surface of the composite head, extend on both sides of raised rib or ridge 36, and border sections 32.

Figure 2 further illustrates the construction. It is seen that elastomer section 18 spans the width of the head sections.

In the normal configuration of the head it is seen that head section 16 is tilted with respect to head section 14 at an angle, typically about 180.

Thus, a force exerted on the brush during brushing is required to tilt section 16 if it is to be more nearly or completely aligned with section 14. The two head sections may be molded in their angled configuration as shown at Figure 1, with the elastomer then added. Alternatively, the two head sections may be molded aligned with each other and then angled upon locating or injecting the elastoner between them.

Referring now to Figure 3, it is seen that the effective curvature of the two head sections 14 and 16 offers improved access to inner and rear surfaces of the teeth. Thus, handle 12 need not be inclined as much as otherwise in order for forward section 16 and its bristles 22 to engage interior surfaces of the lower front teeth. In brushing a straight section of teeth, the deformability of the elastomer section 18 permits section 16 to partially or completely align itself with handle 12 and section 14.

Figure 4 illustrates a second embodiment of the invention, there shows as horizontally disposed, and similar to that of Figures 1 and 2 except for a different construction for angularly joining the two head sections. The elastomer joint of the head is again denoted as 18, with the elastomer itself denoted as 50 and being of the same composition as previously set out, and 15 extends across the width of the head, and is located between the facing ends of sections 14 and 16. A thin integral bridge connection centrally between the two sections is designated as 52, typically being of cylindrical form in transverse cross section. Each end is integral with a respective head section.

The elastomer is seen as completely surrounding bridge 52. This bridge connection may be, in transverse cross section, of any desired form. A top plan view of the head would be similar to Figure 2, except for the absence of grooves 40 and rib 36. As seen at Figure 4, the extent of the elastomer along the toothbrush longitudinal axis is shorter than that of Figures 1 and 2.

Integral connection or bridge 52 performs the same function as bridge 30 of Figure 1, namely, integrally joining the two head sections.

Figure 5 shows a third embodiment, again shown as horizontal. There, the lower surfaces 24 and 26 of bristled head sections 14 and 16 are joined by an intermediate arcuate bottom surface 27 having tufts of bristles 23 extending orthogonally and downwardly therefrom. An elastomer section 18 is generally C shaped and has a bight part 60 and tips or ends 62, the latter located in respective complementary double troughs or double grooves which extend transversely across the head. The elastomer tips are separated by head portion 64, with thin bridges 66, again formed from the molded resin forming the toothbrush, joining the two head sections at the lower surface of the whole head. The C shaped elastomer thus surrounds portion 64 across the width of the head.

The second and third embodiments yield the same cleaning action as shown at Figure 3. The thickness of bridges 52 and 66 is the same as that of bridge 30 of Figure 1.

It is seen that the bridges 30, 52 and 66 of the respective embodiments inhibit longitudinal separation of the two head sections by resisting tensile or other forces which might result in such separation, while the elastomer in the head controls the degree of flexing when head section 16 is subject to brushing forces. The function of the bridges is thus to tether the two head sections together, as well as to set them at an initial angle. When the sections move toward straightening or alignment, each elastomer section is deformed. Such deformation is resisted by the elastomer and to a lesser extent by the resin (polypropylene) bridges so that the sections revert to their normal, angled relationship upon the cessation of brushing force on :forwardmost section 16.

15 Figure 6 illustrates a fourth embodiment which differs from that shown Figure 1 only in the absence of bridge 30 of Figure 1. Instead of bridge the two head sections are coupled by T shaped elastomer section 39, the latter being of the same form as that of section 38 of Figure 1, except that it extends all the way to the lower surface of the head.

Figure 7 shows a fifth embodiment, here the two head sections 14 and .16 being normally aligned. A generally T shaped elastomeric section 41 forms a joint 18 which fills the spaces between the ends of the two head sections 14 and 16, except for bridge 30, identical with bridge 30 of Figure 1, which integrally tethers the two head sections together. Tufts of bristles are slanted with respect to lower head surface 24 of head section 16, the slanting being towards handle 12. Tufts 70 are of successively different lengths, with the longest being near the most remote free and or tip of the head section 16. It is seen that the tips of bristle tufts 70 and 20 form a generally concave brushing surface which is at times, during brushing, flattened upon bending of joint 18.

Figure 8 illustrates a sixth embodiment, similar to that of Figure 7, and differs therefrom only in that the head section 16 tufts, here denoted as 72, extend orthogonally from surface 24. These latter tufts are, as tufts 70, of uniformly different lengths. The longest are near the free end of head section Again, the free ends of tufts 72 and 20 form a generally concave brushing surface which is at times, during brushing, flattened upon bending of joint 18.

In accordance with the second aspect of the present invention, the handle and elastomer for the grip and the head areas can be molded using a three-shot moulding technique. The elastomer is introduced into the head area separately from the handgrip area. This process allows the elastomer for the head section of the brush and the hand grip section to be different elastomeric materials, preferably the elastomers having two different Shore hardness values. For example, in some circumstances, it may be desired to use a softer elastomer for the head area than for the handgrip portion of the brush. The head may then be tufted using conventional staple technology.

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Claims (9)

1. A toothbrush including a head and a handle, the head having an area including a first elastomeric material, the handle having an area including a second elastomeric material, the first elastomeric material and second elastomeric material being different elastomeric materials.

2. A toothbrush according to claim 1, wherein the first and second elastomeric materials have different Shore hardness values.

3. A toothbrush according to claim 1 or claim 2, wherein the first elastomeric material is softer than the second elastomeric material.

4. A toothbrush according to any one of claims 1 to 3, wherein the head is articulated and the first elastomeric material includes a flex area between two head sections, said first elastomeric material positioned between facing ends of said two head sections.

A toothbrush according to claim 4, wherein each of said two head sections has a lower surface from which bristles extend, said lower surface enclosing an angle in an unstressed state. o•

6. A toothbrush according to claim 4 or claim 5, wherein said two head sections are connected by a thin bridge, said thin bridge being surrounded by said first 25 elastomeric material between said two head sections.

7. A method for producing a toothbrush including a head area and a handle area, said method including introducing a first elastomeric material in said head area and introducing a second elastomeric material in said handle area, wherein the first S 30 elastomeric material is different from the second elastomeric material.

8. A toothbrush substantially as hereinbefore described with particular reference to the preferred embodiments and/or the figures. *9 •9 99* 9 9

9. A method for producing a toothbrush substantially as hereinbefore described with particular reference to the preferred embodiments and/or the figures. Dated this twenty-fifth day of August 2003 COLGATE-PALMOLIVE COMPANY Patent Attorneys for the Applicant: F B RICE CO *04 .04. *000 as I.: