Toothbrush with resiliently flexible head

Abstract: A toothbrush with its head in the form of a frame being an extension of the handle. Within and surrounded by the frame there are segments each of which carry one or more tufts of bristles. The segments are not joined to each other but each of the segments is flexibly and resiliently linked to the surrounding frame by one or more thin spines oriented inwardly from the surrounding frame. Preferably the space within the frame contains an elastomer. The segments provide a flexible resilient head.

Description: The present invention relates to a novel article, being a toothbrush, and in particular to a toothbrush having a flexible zone in its head. When brushing one's teeth, particularly with a conventional toothbrush having a rigid head, it can be difficult to reach all parts of the teeth in order to brush the teeth satisfactorily. It is also difficult with such brushes to maintain an optimum angle between the teeth and the head of the toothbrush for effective brushing and cleaning, necessitating continual repositioning of the brush in the hand throughout the brushing process. Consequently, there is a tendency to apply excess brushing pressure to some teeth and insufficient pressure to other teeth. The resultant combination of excess brushing pressure and inadequate cleaning or bad cleaning technique can result in damage to both teeth and gums. Although angled-head toothbrushes have been suggested as an attempt to overcome some of these difficulties, they do not satisfactorily meet all the requirements. Proposals have also been made for toothbrushes having flexible handles or flexible zones in their handles to assist in accommodating the orientation of the bristle-bearing head of the brush to the profile of an individual's teeth and gums. Such toothbrushes are disclosed for example in EP-A-0336641, US 4 520 526, DE-OL-3 640 898, DE-OL-3 612 108, CH-0 155 730 and IT-A-485 723. EP-A-0 613 636 and EP-A-0 604 425 disclose toothbrushes having their heads flexibly linked to their handles. Various toothbrushes with their heads divided into flexibly linked segments are disclosed in US-A-3 188 672, US-A-2 254 365 and US-A-2 438 268. In these disclosures the segments are longitudinally disposed and linked to each other longitudinally. US-A-4 691 405 and DE-A-1 233 821 disclose a toothbrush having a head in the form of a frame surrounding two segments linked at longitudinal ends to the frame. FR-A-1 524 055 discloses a toothbrush head comprising a grooved base of a harder plastic material, the grooves containing a softer plastic material. In some circumstances it is desirable to further improve the flexibility of the head relative to the direction of the handle of the toothbrush. Accordingly the present invention provides a toothbrush according to claim 1. The toothbrush head of this invention, being flexible, can flex under the action of toothbrushing so as to accommodate itself to the differing profiles of individual users' teeth. In particular, teeth generally lie in a "C" shaped curve within the upper and lower jaw, the row of teeth consequently having a convex outer curve and a concave inner curve. The flexible head of the tooth-brush of the inventors can bend to accommodate itself to both the convex and concave curves of the teeth generally better than would be the case with a conventional rigid-headed toothbrush. The handle is extended into the form of a frame wholly or partly surrounding the head, and to which the head is linked flexibly and resiliently. Within such a frame the head may be integrally formed, or may be made as a separate part and fastened into the frame. The head of the toothbrush of this invention is in the form of segments which are not joined to each other but are flexibly and resiliently linked to the frame, the head being in the form of segments linked to the frame by thin spines, e.g. stalk-like bridging portions for example oriented inwardly from a surrounding frame. By varying the dimensions of these stalk-like bridging portions the degree of flexibility and/or resilience of the linking may be varied. The frame may bear bristles, which may have the same or different distribution, length, orientation, colour or stiffness to those on the head. Conveniently bristles when present on the frame may be shorter than those on the head. The bristles may be uniformly distributed over the head and the frame, but preferably the bristles are distributed in discrete tufts. There may be one or more tufts per segment. The space(s) between the head and the frame is partly or wholly filled with a flexible and resilient elastomeric material which may be in the form of a thin diaphragm. By varying the degree of such filling and the material used the degree of flexibility and/or resilience of the head may be varied. The toothbrush (i.e. the handle, head and bristles) of the invention may be made of materials which are conventional in the manufacture of toothbrushes, especially plastics materials. Suitable plastics materials include, for example, polyamides and polypropylenes. An example of a suitable polyamide is the material 'Ultramid B3'™ (marketed by BASF, Germany), for example in an 80:20 mixture by weight (1100 HX:2500 HX). The handle may be of a shape which is conventional in the manufacture of toothbrushes. It may however be advantageously made in the form described in EP-0 336 641-A, more particularly as described in column 1 lines 36-49 thereof. In use, the toothbrush of this invention may be used for cleaning the teeth by an entirely conventional toothbrushing hand action, preferably in a manner recommended by dental health authorities. The toothbrush of the invention may also be used in electrically driven toothbrushes. The invention will now be described by way of example only, with reference to the accompanying drawings, in which: Fig. 1 shows a toothbrush head in the form of segments linked to a frame extension of the handle by stalk-like bridging portions. Referring to Figs 1A, 1B, 1C 1D, 1E, 1F, and 1H, a toothbrush head (51) is surrounded by a frame (52) extension of a handle (53), which are shown in an underside view in Fig 1A, in a top view in Figs 1B and 1F, in longitudinal section view about line A-A in Figs 1C, 1E and 1G, and in a cross sectional view in Fig I D. The overall sideways appearance of this toothbrush is shown in Fig. 1H. The head (52) is in the form of a series of segments (54), which are flexibly and resiliently linked by stalk-like portions (55) to the frame (52), leaving a narrow gap (56) between the head (51) and the frame (52), and between the segments (54). The segments (54) carry one or more tufts (52) of bristles. In Figs 1F and 1G the gap (56) is shown as being partly filled with an elastomeric material (58) which is of a different colour to that of the segments (54) and the frame (52). In Figs 1D and 1E the head (51) is shown as flexing under the action of pressure of the point indicated by the arrow into a concave curve of tufts (57) accommodating itself to the outer side of the line of the teeth.

Claims: A toothbrush, having a handle (53) and at one end thereof a bristle-bearing head (51), wherein the head (51) is in the form of a frame (52) being an extension of the handle (53), within and surrounded by the frame (52) there being two or more segments (54), each of which carry one or more tufts (57) of bristles, the segments (54) not being joined to each other but each of the segments (54) being flexibly and resiliently linked to the surrounding frame (52) by thin spines (55) oriented inwardly from the surrounding frame (52), characterised in that there is a space between the frame (52) and the segments (54), and between the segments (54) which contains a flexible and resilient elastomeric material (58). A toothbrush according to claim 1 characterised in that the segments (54) within the frame (52) are integrally formed with the frame (52), and the thin spines (55) are in the form of stalk-like bridging portions of the material of the segments and the frame. A toothbrush according to claim 1 or 2 characterised in that the frame (52) completely surrounds the head. A toothbrush according to any one of claims 1 to 3 characterised in that the frame (52) bears bristles (57). A toothbrush according to claim 4 characterised in that the bristles (57) on the frame (52) differ in their distribution, length, orientation or stiffness to the bristles (57) on the segments (54). A toothbrush according to any one of claims 1 to 5 characterised by bristles (57) on the segments (54) distributed in discrete tufts, and by more than one tuft per segment (54). A toothbrush according to any one of the preceding claims characterised in that under the action of pressure applied to the ends of bristles (57) the head (51) flexes to form a concave curve of tufts (57) accommodating itself to the outer side of the line of the teeth.

Inventors: HALM HANS, HALM, HANS, Halm, Hans c/oSmithKline Beecham Cons. Healthcare
Applicants: SMITHKLINE BEECHAM CONSUMER, SMITHKLINE BEECHAM CONSUMER HEALTHCARE GMBH
Application year: 1992
Main classification: A46B7
IPC codes: A46B7, A46B5