This invention relates to a novel article, being a toothbrush having a flexible-resilient region in its handle.

Toothbrushes having a flexible-resilient region between their handle and their bristle-bearing head are known. Their increased flexibility enables the brush to be more easily accommodated to the contours of the mouth and to reach otherwise relatively inaccessible areas of the teeth. One known type of brush, disclosed in EP-A-89303135.1 has a flexible-resilient region in the form of a portion folded into one or more V or 'U' folds. Another known type of brush, disclosed in IT-485723 has a flexible- resilient region in the form of a metal leaf spring along which are mounted a number of plastic rings.

This invention provides a novel form of such a toothbrush. According to the invention a toothbrush comprises a handle and a bristle-bearing head, both made of plastics material, and located therebetween a flexible- resilient region which is either (a) an integral corrugated region or (b) an integral flexible resilient core surrounded by an elastomeric region which may be corrugated, wherein the term "corrugated" means having corrugations in the form of longitudinally alternating portions of larger and smaller cross section relative to the longitudinal axis of the toothbrush.

The longitudinal axis of the toothbrush is the axis running for the length of the brush between the end of the head furthest from the handle and the end of the handle furthest from the head.

The handle of the toothbrush may be of a known type, and may for example be provided with grip-improving features such as ridges, grooves, dimples, raised spots, elastomeric e.g. rubber or synthetic rubber grip mats etc., for example of the type described in EP-A-89303135.1. The bristle-bearing head and the bristles thereon may also be of a known type for example the bristles may be of natural or synthetic, e.g. plastics material, fibre. The bristles may for example have an inner region of a different colour to the surface region so that as the bristles wear away with use they change colour. Bristles of this type are disclosed in

GB 1076967 and EP-A-0303202.

The function of the corrugations is to control the flexibility and resilience on bending of the flexible-resilient region. Their effect will be determined inter-alia by their number, shape and size. Suitably if there are n portions of larger cross section, where n is an integer of value 1 or more, there can be n or (n+1) portions of smaller cross section. Suitably there should be at least one portion of a larger cross section alternating with, ie between, two adjacent regions of smaller cross section. For example n may 1 to 10, eg specifically 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10. Suitably there may be 3 portions of larger cross section and 3 portions of smaller cross section.

The shape of the portions may be such that a longitudinal section through the region may be longitudinally centrosymmetric, with each half being sawtooth, wavy, or crenellated etc. The relative difference between the larger and smaller cross section may be such that the smaller cross section is between 10-90%, for example 30-70%, for example 40-60% of the larger cross section.

The cross sectional shape of the corrugated or elastomeric region may be any convenient shape, for example circular, oval, substantially square or rectangular, e.g. having rounded or chamferred corners, diamond shaped, lozenge shaped, triangular, polygonal etc. The cross sectional shape of the region may be such that the dimension in one axis is less than that in another axis, so that the region has enhanced flexibility in one axial direction. Suitably the section may be circular, oval or lozenge shaped. One or more of the cross sectional dimensions of the region may also vary along the length of the region so that the cross sectional dimension tapers along the length of the region, e.g. narrowing toward the head so as to enhance flexibility near the head.

In a toothbrush of type (a) above, the corrugated region may for example be an integral moulding with the handle and the bristle bearing head.

In a toothbrush of type (b) the core may be a region of reduced cross sectional dimension relative to both the handle and the head. The cross sectional dimension of the core may be adapted to the cross section of the handle and head at either end of the core either abruptly in a step, in a

steep or gentle slope, or in a smooth gradation at either end of the core. At any point along its length the cross sectional dimension of the core region may for example be between 10-90%, for example 30-70%, for example 40-

60% of the cross sectional dimension of the surrounding elastomeric region. The core may itself be corrugated or may be perferated, for example to enhance binding to the surrounding elastomeric region. The cross sectional shape of the core may be any convenient shape, for example as for the shapes suggested for the elastomeric or elastomeric region described above although the shapes of the core and surrounding corrugated region need not correspond. The cross sectional shape of the core may be such that the dimension in one axis is less than the dimension in another axis, so that the core has enhanced flexibility in one direction.

The handle, head, integral corrugated region and core may be made from conventional resilient and flexible plastics materials from which toothbrushes are normally made. The elastomeric region may be made of conventional elastomeric materials such as rubber, synthetic rubber and elastomeric polymers, and may for example be formed around the core in a subsequent moulding operation. The corrugated and elastomeric region may be made of a different colour to the handle and the head, for aesthetic reasons, e.g. to indicate and/or emphasis its construction. Suitable plastics and elastomeric materials are those suggested in EP-A- 89303135.1.

The invention will now be described by way of example only with reference to:

Fig 1 which shows a longitudinal section through a toothbrush of type (a) above.

Fig 2 which shows a longitudinal section and a cross sectional view through a toothbrush of type (b) above.

Fig 3 which shows a longitudinal section through a toothbrush of type (a) in which the cross sectional dimension tapers along the length of the flexible resilient region.

Referring to Fig 1, a toothbrush has a handle (1), and a bristle bearing head (2). Between handle (1) and head (2) is located a flexible-resilient region, being an integral corrugated region (3), in the form of portions having a larger cross section (4) and portions having a smaller cross section (5). In Fig IB pressure has been applied to the head (2) in the direction shown by the arrow, under the action of brushing teeth (not shown), and the corrugated region (3) has flexed. On release of the pressure the resilience of region (3) causes it to return to the non-flexed position as shown in Fig 1A. Fig IC shows a toothbrush having a corrugated region (3) which has three portions of larger cross section (4) and three portions of smaller cross section (5).

Referring to Fig 2, a toothbrush has a handle (1) and a bristle-bearing head (2) made of plastics material. Between handle (1) and head (2) is located a flexible-resilient region comprising a core (6) integral with both the handle (1) and head (2), and being of reduced cross section relative to both. Surrounding core (6) is an elastomeric region (7) which is corrugated in the form of portions having a larger cross section (8), and portions having a smaller cross section (9).

In Fig 2B pressure has been applied to the head (2) in the direction shown by the arrow, under the action of brushing teeth (not shown), and the flexible-resilient region (6)-(9) has flexed. On release of the pressure the resilience of the region (6)-(9) causes it to return to the non-flexed position as shown in Fig 2 A.

In Fig 2C a cross sectional view through the flexible-resilient portion about line C-C of Fig 2A is shown, looking in the direction of the arrows. The core (6) is shown as being of generally rectangular cross section, having a preferred flexing direction in the direction of the shorter axis. The elastomeric region (7) is shown as being of circular cross section, having portions of larger cross section (8), and of smaller cross section (9).

Referring to Fig 3, a toothbrush has a handle (1) and a bristle-bearing head (2). Between handle (1) and head (2) is located a flexible resilient region (10) of general construction similar to that of Fig 1, except that the cross sectional dimension of the portions of larger cross section (11 ) and of smaller cross section (12) progressively decreases from the handle end to

the head end of the region (10), so that the region generally tapers in the longitudinal direction, enhancing flexibility in the vicinity of the head end of the region (10).

In Fig 3B pressure has been applied to the head (2) in the direction shown by the arrow, under the action of brushing teeth (not shown), and the flexible-resilient region (10) has flexed. On release of the pressure the resilience of the region (10) causes it to return to the non-flexed position shown in Fig 3A.