Toothbrush.

This invention relates to toothbrushes.

Toothbrushes are well known devices, generally comprising an elongate grip handle with at one end a head bearing oral cleaning elements such as bristles to clean such oral surfaces as the teeth and gums. Generally the handle and head of toothbrushes are made of plastics materials by a process of injection moulding. There is an ongoing problem of the need to reduce manufacturing costs, and one solution to this problem is to reduce material costs. Also, if the toothbrush handle is relatively bulky increased time needs to be allowed in the injection moulding process for the handle to cool. One solution to this problem is suggested in US-A-2003/0208870 which discloses a toothbrush in which the handle includes one or plural voids to reduce the amount of plastics material that is needed and to reduce the cooling time. In US-A-2003/0208870 the voids are shown as open on the surface of the toothbrush. It is an object of the present invention to provide a further, improved, solution to these problems.

According to this invention a toothbrush grip handle made of a plastics material is provided, connected or connectable to a toothbrush head bearing oral cleaning elements, characterised by the handle including one or plural voids having an opening at the surface of the handle, and said void(s) being at least partly closed by a film material.

The toothbrush grip handle of the invention addresses the problem outlined above in that the void(s) reduce the amount of plastics material needed relative to a toothbrush handle of the same overall size. However by closing the void with a film material the entry of water, contaminants etc. into the void, which could result in mould etc. growth is thereby reduced. In the case of children's toothbrushes an additional problem is also thereby solved. Small children tend to chew the handle of their toothbrushes and if voids are open on the surface of the handle their teeth may become caught in open voids, with the possible consequence of injury to their teeth and adjacent gum tissues. By closing the voids this danger is reduced or eliminated. The invention further provides a toothbrush comprising a grip handle as defined above, combined with a toothbrush head, suitably integrally made with the toothbrush head.

Suitably the handle and head and any neck region between the head and handle are integrally made in one piece of the plastics material, as is common in the art.

Suitably the oral cleaning elements are bristles, as is common in the art, and plural bristles may be made into tufts which may be fixed into the head in a conventional manner.

Suitably each void may comprise a cell partly bounded by walls of the plastics material of which the handle is made, and partly bounded, being at least partly closed, by the film material. Such cells may for example be substantially tetragonal, although other shapes e.g. hexagonal prismatic are also suitable. Suitably there may be plural voids in the handle. Plural voids may be arranged serially along the longitudinal direction of an elongate toothbrush grip handle. Plural voids may be in communication with each other, or may be separated from each other by bulkhead walls e.g. of the plastics material of which the handle is made. Typically a toothbrush grip handle comprises an end longitudinally distant from the head, and an end longitudinally closer to the head, and side surfaces running longitudinally between these ends. Suitably the voids are open at one or more of these side surfaces. Such bulkhead walls may extend across the grip handle perpendicular to the head-handle direction. When plural voids are in communication this may be achieved by openings in bulkhead walls between voids or bulkhead walls which only partially close the voids.

Typically the walls of the cells that define the outer surface of the grip handle may be l-2mm thick. Typically bulkhead walls between cells may also be l-2mm thick. Suitably the void(s) may make up 30% or more, e.g. 40% or more, e.g. 50%, e.g. 60% or more of the internal volume of the grip handle of the toothbrush.

Plural voids may all be open on the same surface of the grip handle. The openings of plural voids may all be in a plane.

The plastics material may be any of the known plastics materials from which toothbrushes are normally made, e.g. polypropylene, polyamide, acrylonitrile- butadienestyrene etc., and a conventional injection moulding process may be used to manufacture the grip handle.

Preferably the film material completely closes the void so that the void is a closed cell bounded by the film material and the plastics material walls of the cell.

The film material may for example be a flexible film of a plastics material, a metal foil, a paper or paper-based material, or a laminate, e.g. of two or more of these previously mentioned materials. Preferably the film material is water resistant to withstand contact with water as might be experienced during tooth brushing. The film material may be attached to the grip handle by for example shrink-wrapping or an adhesive or by welding. Preferably the attachment of the film material to the grip handle is such that water cannot pass between the film material and the plastics material.

Suitably the film material may also comprise a label having textual or pictorial matter printed or otherwise displayed thereon. Advantageously this enables different graphic designs to be applied to the toothbrush by the relatively simple procedure of printing a design on the film material before this is applied to the toothbrush.

The invention will now be described by way of example only with reference to the accompanying figures of which: Fig. 1 shows a plan view of a toothbrush according to this invention.

Fig. 2 shows a side view of the toothbrush of Fig. 1.

Fig. 3 shows an underside view of the toothbrush of Fig. 1.

Fig. 4 shows a cross sectional view of the toothbrush of Fig. 1 at the line A-A of Figs. 1 and 2. Referring to Figs. 1 - 4 a toothbrush of this invention 10 overall is shown, comprising a grip handle 11 integrally made with a toothbrush head 12 of a plastics material typically polypropylene. The toothbrush head 12 has a surface 13 which bears conventional bristles (not shown). The handle 11 is elongate along the handle- head longitudinal direction L-L and has longitudinally spaced ends 23, 24 respectively distant from and closer to the head 12. Between the handle 11 and the head 12 is a neck region 14 of which the part adjacent to handle 11 is formed into "S" shaped folds.

The handle includes plural, i.e. eleven (there may be more or less) voids 15, each void 15 having an opening 16 at the surface of the handle 11. As seen in Fig 4 the handle 11 is substantially rectangular in cross section cut across the longitudinal direction L-L, and the voids 15 all have their openings 16 on the same surface 25 of the grip handle 11, being a side surface, such that as seen in Fig. 2 the openings 16 of plural voids 15 are all substantially in the plane of the side surface 25, i.e. a plane parallel to the paper of Fig. 1. Each void 15 comprises a cell partly bounded by outer

walls 17 which define the outer surface of the grip handle 11, and bulkhead walls 18 integrally made of the plastics material of which the handle is made. The voids 15 are each substantially tetragonal in shape, with the bulkhead walls 18 extending across the grip handle perpendicular to the longitudinal direction L-L, and are arranged serially longitudinally along the longitudinal direction L-L of the handle, the voids 15 being separated from each other by the bulkhead walls 18 between longitudinally adjacent voids 15. Typically the walls 17,18 are l-2mm thick, hi the embodiment illustrated the volume of the voids 15 comprise ca. 40-50% of the overall internal volume of the handle 11. The opening 16 of each of the voids 15 is closed by a film material 20, shown in Fig. 4, so that the void 16 is a closed cell bounded by the film material 20 and the plastics material walls 17,18 of the cell, hi Fig. 4 the thickness of the film material 20 is exaggerated.

This film material is an water-resistant plastics film material of generally known type, backed with a water-resistant adhesive, and is adhesively attached to the outer surface of the handle 11 in a known manner to cover the openings 16 of voids 15. Alternatively for example the film material 20 may be heat shrink wrapped around handle 11 in a generally known manner. As seen in Fig. 3 the film 20 is shown in the form of a generally cylindrical sleeve 20 which has been applied by shrink fitting over the handle 11, and having longitudinal ends 21, 22. The outer surface of the film material 20 is marked with textual and/or pictorial matter 23 e.g. a manufacturer's or marketer's trade mark. Although shown in Fig.4 completely surrounding the handle 11, the film material 20 need only cover the openings 16 of the voids 15 to achieve the invention.