BRUSHES

Abstract: A toothbrush consists of a handle (1), a brush head (4, 5) bearing an array of bristles (3), and a pair of interlocking combs (20, 21) on the handle, the combs being movable between a position lying wholly against or within the handle (1) to a position of engagement with the bristles (3). The combs (20, 21) may be varied in distance from the base (4) in which the bristles (3) are set to adjust the bristle hardness, or may cause the bristles (3) to bend to vary the bristle angle, or may cause the bristles to vibrate. The brush head (4, 5) may be detachable and disposable.

Description: BRUSHES This invention relates to brushes, particularly toothbrushes . Brushes are known in which the effective hardness of the brush can be varied. One way of doing this is to surround tufts of bristles set in a brush base with an apertured plate which may lie against the base in which the tufts are anchored, or which may be moved away from it along the tufts by a certain distance, so increasing the hardness of the brush by reducing the length of freely bendable bristle which extends from the free end of the bristles to the apertured plate. British Patent Specifications 1604281 and 1604878 disclose toothbrushes of such a construction while British Patent Specification 1335639 discloses a variety of brushes which can be adjusted in hardness by a movable plate. US specification 4109338 discloses an assembly of a broom and dustpan in which the latter can be clipped on to the handle of the broom and positioned to back up the bristles, restricting their movement in one direction. US Patent Specification 5142726 discloses a toothbrush with a two-part handle, one portion of which consists of a flexible member which can be depressed by the user's thumb causing its end surrounding the bristles of the brush to move away from the base of those bristles and towards the free end. US Patent specification 4393535 discloses a circular brush for cleaning distributor caps in which the effective diameter of the brush may be varied by varying the position relative to a circular bundle of bristles of an external cylindrical sleeve. All of these constructions are complex and this leads to increased manufacturing costs. A further problem which arises with these prior art brushes is the tendency for the mechanism to get clogged, particularly with dust, toothpaste or the like. Most are ill adapted for cleaning the hardness-varying mechanism. I have now found that the benefits of variable hardness brushes may be retained, but with manufacturing simplicity imparted by providing the hardness-varying mechanism in the form of a comb or combs which can be inserted laterally into the gaps between adjacent lines or rows of tufts set in a brush head. Such an arrangement provides a number of further unforeseen advantages, which are detailed below. According to the present invention, there is provided a brush construction consisting of a handle, a brush head bearing an array of bristles, and bristle adjustment means located on the handle which can move from a position in which said means lie wholly against or within the handle to a position in which they may engage around and within the array of bristles. In a first arrangement, the bristle adjustment means are arranged so that their distance from the base of the brush head bearing the bristles is variable along the direction of the bristles, whereby the hardness of the brush is variable. In a second arrangement, the bristle adjustment means are arranged to oscillate, so that the bristles are caused to vibrate. The oscillation may be reciprocatory or rotary. In a third arrangement, the bristle adjustment means are arranged to cause the bristles to bend, so that the angle of the bristles with respect to the base of the brush head is varied. In a highly preferred construction, which is particularly applicable to the manufacture of toothbrushes, a brush in accordance with the invention is characterised by a pair of comb members swivellably mounted on the brush handle such that they may be swivelled from a position in which the teeth of the comb are not engaged with the bristles of the brush to one in which they are. In a particularly preferred embodiment, the brush consists of a handle to which the swivellable comb members are pivoted and a disposable bristle- carrying head. This is particularly valuable in connection with toothbrushes which often lose their shape and stiffness through use and which accordingly need to be regularly replaced. Using the handle and exchangeable head configuration, the head may be exchanged for a new one while retaining the handle and combs which, as will be appreciated, is relatively more costly to manufacture. Thus, the benefits of variable hardness may be achieved without resort to building them into a brush head which, when it wears out, has to be discarded. The mechanism for moving the combs relative to the head is, of course, likewise built into the handle and comb structure, so the head can be very plain and manufactured at a cost rendering it easily disposable without qualm. Preferably the or each comb member is swivellable from a position in which the teeth are engaged in the array of tufts of bristles to one in which the combination is entirely folded into the handle. The mechanism for moving the comb(s) toward or away from the base in which the bristles are set may be any convenient mechanism and is one which is preferably robust while nevertheless being easy (and accordingly inexpensive) to manufacture. Some possibilities for this are described further below. Preferably, toothbrushes in accordance with the invention have a pair of combs which can be swung to engage between the bristle tufts on the head of the toothbrush from opposite sides and which, when so engaged, are engaged with one another, optionally with a clipping action, so that the inter-engaged comb teeth can be easily moved as a unit. The base of the brush head in which the tufts of bristles are set may be configured with grooves in the spaces between the bristles, the grooves being dimensioned to receive the teeth of the comb member (s). In a further development of the invention, the bristle adjustment means may be designed so as to cause the interengaged comb teeth to move relative to the bristles if the overall pressure applied to the bristle array exceeds a certain threshold in a fashion so as to reduce the overall hardness of the brush. This may be achieved by a variety of design solutions, the particular construction and mechanism employed depending on the type of brush in question. Such a feature is of value in circumstances where in the intended use of the brush, it is desirable to limit the brushing effect to a certain extent or degree. One particular area in which this is of value is that of toothbrushes. Over recent years, it has emerged that a major contributory factor to gingival recession is that of over-hard brushing using too hard a toothbrush. There is a temptation for toothbrush users to apply excessive force when brushing which, while it may have some (but probably not very much) effect on the efficiency with which the enamel surfaces of the teeth are cleaned, has the major disadvantage that it promotes receding gums. Although gingival recession may have a number of causes, studies have established beyond doubt that too much too hard brushing is an important contributory factor. By suitably configuring and mounting the adjustment means, toothbrushes in accordance with the invention may be arranged to retain the adjustability of hardness features discussed above while being rendered less likely to cause gingival recession if improperly used by the ability of the adjustment means to move back towards the brush head carrying the bristles if too great pressure is applied to the overall array of bristles. In the case of the comb member construction described above, the mechanism for moving the comb(s) toward or away from the base may be constructed with a certain amount of give so that if too much pressure is applied while brushing the teeth, the comb(s) is moved towards the base in which the array of bristles is set, thus rendering the hardness of the brush less and reducing the possibility of gum damage. If the postion of the comb(s) is determined via a suitable adjustment mechanism, building resilience into that mechanism can achieve the desired effect. The amount of give if excess pressure is applied may vary linearly with the amount of excess pressure, or, for example non-linearly, so that the hardness of the brush overall remains the same until a certain threshold pressure is applied, whereupon it suddenly becomes rather softer, the hardness returning automatically to the previous setting once the excess pressure is removed. Although for optimum dental hygiene it is clearly desirable to train toothbrush users to use their brushes properly, provision of an automatic mechanism for reducing the potential for adverse effects if improper brushing techniques are applied is clearly of value in improving dental hygiene; the adverse effects of inadvertently over-hard brushing are removed or moderated. The invention is illustrated by way of example with reference to the accompanying drawings in which: Figure 1 is a diagrammatic perspective view of a toothbrush handle and disposable head Figure 2 is a diagrammatic view looking end on to the bristles of the disposable head Figure 3 is a general arrangement drawing of the toothbrush according to the invention, but with the hardness varying mechanism omitted for clarity Figure 4 is a diagrammatic view of the brush showing a pair of swivellable combs Figure 5 is an exploded view of the combs when in their operative position Figure 6 is a view of the brush with the bristles omitted Figure 7 is a partial view of the handle showing a hardness varying actuator mechanism Figure 8 is a side view of the brush in its softest setting Figure 9 is a side view similar to Figure 8 showing the brush with the bristles stiffened and Figure 10 shows side and plan views of an alternative construction. Referring first to Figure 1 , this shows part of a toothbrush handle 1 into which a detachable head 2 may be fitted. As can be seen, the head consists of a set of tufts of bristles 3 which are set in a base 4 from which an elongate member 5 extends having a shaped end portion 6 which may be inserted into a slot 7 in the end of handle 1. Built into handle 1 is a press pad 8 which may, by internal mechanism not shown in Figure 1, enable the release of the portion 6 from the handle. Also visible in Figure 1 is an open-ended compartment 14 with side slots 15 and 16 for the receipt of two comb members, described in more detail below. As can be seen in Figure 1, the shaped portion 6 and elongate part 5 have an upwardly facing groove 10 in them for a purpose described below. Figure 3 shows the whole of handle 1 with the head 2 inserted. Clearly visible on the upper side of handle 1 is a slide member 12 which may be slid along a slot 13 for the purpose of varying the effective hardness of the brush. Figure 4 shows the combs 20, 21 which may be inserted laterally into the array of bristles. As can be seen, these are pivoted at 24, 25 respectively to the handle 1 and may be swung back to allow insertion of the head into handle 1 or its removal into the position shown in Figure 4. The comb 20 may be folded back into handle 1 passing through slot 16, and comb 21 passing through slot 15. Figure 5 shows details of the construction of the two combs 20 and 21 apart for the sake of clarity, and the bottom of Figure 5 shows the two members together and in a section transverse to the teeth of each comb. As can be seen by inspecting Figure 5, teeth 28 shown in cross- section are part of comb 20, while teeth 29 are part of comb 21. When assembled on to the handle 1, and with the combs swivelled in, the structure is as shown in Figure 6. In this figure, the bristles have been omitted for the sake of clarity. Referring now to Figure 7 to 9 , there show more details of the mechanism for adjusting the effective hardness of the brush. As can be seen from the longitudinal sectional view which forms the lower portion of Figure 7, attached to actuation member 12 is an elongate rod 30 which extends forwardly from actuating member 12 through an internal slot in the handle. When the actuating member 12 is in its rearwards position, i.e. most remote from the bristles 3 of the brush, the rod 30 is wholly retracted within handle 1. This is the situation shown in the side view of the brush shown in Figure 8. If, however, the actuation member 12 is pushed forwards, i.e. towards the bristles, then rod 30 moves along groove 10 which, as can be seen in Figure 1, becomes shallower as it approaches the bristles 3. This forces elongate member 5 to flex and the bristles 3 to be pulled downwards relative to the combs 20, 21, thus reducing the free-to-flex portions of the tufts 3 and accordingly increasing the effective hardness of the brush as seen in Figure 9 compared with that seen in Figure 8. Figure 10 shows an alternative embodiment in which instead of a sliding mechanism with an actuation member 12, the combs are pivoted around an axis 40 and can be moved as a unit away from the base 4, i.e. up the bristles 3, by depressing a bridge member 41, which joins the two combs together, in the downward direction as seen in the upper portion of Figure 10. A spring 43 is mounted in the end of handle 1 to bias the pair of combs to a position as shown in upper half of Figure 10. The combs may be made of resilient plastics material and may be formed of high quality engineering material so that they do not easily suffer damage. They may have formations on them formed by moulding, pressing or machining enabling them to be clipped together or released from one another, thus improving the integrity of the slotted member formed by the two inter-engaged combs with the teeth of each comb lying between a row of bristle tufts on the brush head. The sides of the teeth of the combs may be serrated to improve the engagement of the teeth in the array of tufts of bristles. Numerous variations in design may be made to the specific brushes illustrated in the drawings. For example, the adjustment mechanism rod may be actuated by a slider which runs in lateral slots at the side of the handle and through which it is connected to the rod, rather than having a slot 13 in the face of handle 1. Pivots 24 and 25 may be constructed using removable pivot pins enabling easy replacement of the comb members if damaged. A further possibility is to mount the comb members in a way enabling them to be moved as a unit in the direction of the length of handle 1. Moving them forwards would then tilt the array of bristles 3 forwards , and moving them back towards handle 1 would tilt the array of bristles 3 backwards; this enables the bristles to be angled at less than 90° to the bristle base 4 , which can be desirable for certain types of brushing action. While in Figures 4 and 5 the teeth of the combs 20, 21 are shown as straight-sided, they could alternatively be provided with indentations to accommodate the tufts of bristles 3 when the combs are in the interlocked position. Finally, it is to be appreciated that the comb member construction could be charged either positively or negatively with respect to the rest of the brush enabling oppositely charged plaque or tartar particles to be attracted to the bristles during the brushing process .

Claims: CLAIMS 1. A brush construction consisting of a handle, a brush head bearing an array of bristles, and bristle adjustment means located on the handle which can move from a position in which said means lie wholly against or within the handle to a position in which they may engage around and within the array of bristles. 2. A brush construction according to Claim 1 in which the bristle adjustment means are arranged so that their distance from the brush head bearing the array of bristles is variable along the direction of the bristles, whereby the hardness of the brush is variable. 3. A brush construction according to Claim 1 in which the bristle adjustment means are arranged to oscillate, so that the bristles are caused to vibrate. 4. A brush construction according to Claim 3 in which the oscillation is reciprocatory. 5. A brush construction according to Claim 3 in which the oscillation is rotary. 6. A brush construction according to Claim 1 in which the bristle adjustment means are arranged to cause the bristles to bend, so that the angle of the bristles with respect to the brush head bearing the array of bristles is varied. 7. A brush construction according to any one of the preceding Claims in which the bristle adjustment means is in the form of a grid formed by a pair of interlocking combs. 8. A brush construction according to any one of the preceding Claims which is a toothbrush. 9. A brush construction according to any one of the preceding claims wherein the bristle adjustment means is designed to move relative to the bristles when the overall pressure on the bristle array exceeds a certain threshold whereby to reduce the overall hardness of the brush. 10. An accessory device comprising a pair of inter- engageable comb members movable one relative to another and means for fitting the device on to the handle of a toothbrush, the accessory device being adapted and configured to form with the toothbrush, when so fitted, a brush construction according to Claim 1. AMENDED CLAIMS [received by the International Bureau on 3 November 2000 (03.11.00); original claims 1, 2, 7-10 amended; remaining claims unchanged (2 pages)] 1. A toothbrush construction consisting of a handle, a detachable exchangeable brush head bearing an array of bristles, and bristle adjustment means mounted on the handle and movable from a position in which the bristle adjustment means lie wholly against or within the handle to a position in which they may engage around and within the array of bristles on the brush head. 2. A toothbrush construction according to Claim 1 in which the bristle adjustment means are arranged so that their distance from the brush head bearing the array of bristles is variable along the direction of the bristles, whereby the hardness of the toothbrush is variable. 3. A toothbrush construction according to Claim 1 in which the bristle adjustment means are arranged to oscillate, so that the bristles are caused to vibrate. 4. A toothbrush construction according to Claim 3 in which the oscillation is reciprocatory. 5. A toothbrush construction according to Claim 3 in which the oscillation is rotary. 6. A toothbrush construction according to Claim 1 in which the bristle adjustment means are arranged to cause the bristles to bend, so that the angle of the bristles with respect to the brush head bearing the array of bristles is varied. 7. A toothbrush construction according to any one of the preceding Claims in which the bristle adjustment means is in the form of a grid formed by a pair of interlocking combs . 8. A toothbrush construction according to any one of the preceding Claims in which the bristle adjustment means is in the form of at least one comb which may be inserted laterally into gaps between adjacent lines or rows of tufts set on the detachable exchangeable brush head. 9. A toothbrush construction according to any one of the preceding claims wherein the bristle adjustment means is designed to move relative to the bristles when the overall pressure on the bristle array exceeds a certain threshold whereby to reduce the overall hardness of the brush. 10. An accessory device comprising a pair of inter- engageable comb members movable one relative to another and means for fitting the device on to the handle of a toothbrush, the accessory device being adapted and configured to form with the toothbrush, when so fitted, a toothbrush construction according to Claim 1. STATEMENT UNDER ARTICLE 19 (1) The claims have been amended compared with those originally filed in order more clearly to distinguish the invention described in the specification from the disclosures of the documents identified in the search report. The claims are all now clearly directed to toothbrush constructions in two parts, viz. a handle and the head and with bristle adjustment means fitted to the handle, but adapted to engage the bristles on the head. The amendments have no impact on the drawings, but the description will need to be brought into line during later processing.

Inventors: FOTI ROMANO, FOTI, ROMANO
Applicants: FOTI ROMANO, FOTI, ROMANO
Application year: 2000
Main classification: A41B9
IPC codes: A46B5, A46B9