HK1167300B - Toothbrush - Google Patents

Description

Tooth brush

The patent application of the invention is a divisional application of Chinese patent application No.200710186375.1 named "toothbrush" filed on 14/11/2007, wherein the patent application No.200710186375.1 is a divisional application of Chinese patent application No.01806615.1 named "toothbrush" filed on 8/3/2001. The divisional application was filed because of the unity noted in the notice of the first examination opinion directed to patent application No. 200710186375.1.

Technical Field

The present invention relates generally to the field of oral care, and in particular to toothbrushes.

Background

Japanese patent document 3-312978 discloses a toothbrush having a multiplicity of nylon bristle tufts. In a first embodiment as shown in figures 1, 2 and 3, a plurality of cylindrical depressions are provided in the brush head in a direction perpendicular to the direction of the longitudinal axis of a handle, and the depressions are equally spaced. In which recesses cylindrical rotating bodies 5 are respectively contained. On the circumferential surface of the rotating body 5, projecting strip portions 5a are formed in the axial direction, and these projecting strip portions are disposed in such a state as to be located at the opening portions of the recessed portions. In the opening portion of the concave portion, contact surfaces are formed to be placed on both sides. At both ends of the upper surface of the protruding strip portion 5a, nylon bristles 6 are uprightly provided.

The arrangement described above allows the bristles 6 to rotate during use of the toothbrush, as shown in figure 3. One problem with this toothbrush is that two tufts of bristles are fixed to each strip portion 5a and must therefore rotate in unison. As a result, individual bristle tufts cannot rotate independently of other "cooperating" bristle tufts. Individual bristle tufts may be prevented from preferentially inserting between two teeth during brushing because the cooperating bristle tufts would contact the teeth differently and interfere with the rotation of the bristle tufts.

Fig. 4, 5 and 6 disclose a second embodiment in which each tuft of bristles is secured to the head by a ball and socket type arrangement. And this embodiment allows each bristle tuft to swivel independently of the other bristle tufts, which creates a drawback. If the bristle tufts are angled laterally outward toward the head and the bristle tufts are disposed near the interface between the side surfaces and the top surface of the teeth, there is an increased chance that the bristle head will not even contact the teeth during brushing. In addition, the bristle tufts will assume a random orientation after the brushing process is transferred from the attraction of the toothbrush.

Disclosure of Invention

The present invention is directed to overcoming one or more of the problems set forth above. Briefly, in accordance with one aspect of the invention, a toothbrush includes a handle, a head extending from the handle, and a plurality of tooth cleaning elements, such as tufts of bristles, extending from the head. Each tooth cleaning element is supported for rotation primarily about only one axis. Each tooth cleaning element can rotate independently of the other tooth cleaning elements.

By having each tooth cleaning element supported for rotation about only one axis, the problems associated with ball and socket bristle tuft support as described above are avoided. That is, the appearance of the toothbrush will be more appealing by increasing the chance that the tooth cleaning elements will remain in contact with the teeth during brushing.

In addition, since each tooth cleaning element can be rotated independently of the other tooth cleaning elements, the problems described with reference to the first embodiment can be avoided. Each tooth cleaning element is capable of achieving a preferred penetration between teeth without interference from rotation of the other tooth cleaning elements.

Drawings

These aspects, objects, features and advantages of the present invention will be better understood from the following detailed description of the preferred embodiments and appended claims when taken in conjunction with the accompanying drawings.

FIG. 1 is a perspective view of a toothbrush in accordance with a first embodiment of the present invention;

FIG. 2 is a partial cross-sectional view of the head and one of the tooth cleaning elements of the toothbrush shown in FIG. 1;

FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 2;

FIG. 4 is a front view of another tooth cleaning element;

FIG. 5 is a side view of the tooth cleaning elements shown in FIG. 4; and

fig. 6 is a graph showing a comparison of interproximal residence time between moving and fixed bristle tufts in the interproximal spaces between teeth.

Detailed Description

Beginning first with fig. 1, a toothbrush 8 includes a handle 10 with a head 12 extending from the handle 10. The head 12 includes a first set of tooth cleaning elements 14, such as bristle tufts, which are secured to the head in a conventional manner (e.g., by tufting or heat-tufting). The elements 14 are designed to clean the exposed surfaces of the teeth.

A second set of tooth cleaning elements 16 are secured to head 12 such that each element is independently rotatable about an axis during use of the toothbrush. Each element 16 may be a tuft of bristles or a single blade made integrally of plastic or rubber. The elements 16 are designed to penetrate between the teeth to clean the space between the teeth.

The residence time between the neighbours of elements 16 is significantly increased compared to elements 14 which are rigidly fixed to head 12. Experiments were conducted in which the interproximal residence time was determined for fixed bristle tufts angled forward at approximately 0 degrees (e.g., elements 14) and 16 degrees, and for rotating bristle tufts, such as elements 16. The bristle tufts each have an average of 40 bristles each having a diameter of 7 mils. The residence time was measured on a filament side tester (SFT) with an applied load of 4 g/tuft and a speed of between 0.5 and 10 in/s.

Fig. 6 shows the movable bristle tufts and the fixed bristle tuft times adjacently in the gaps between the teeth, wherein the curves are marked from top to bottom by the symbol "□" (movable: y 0.7354x, respectively)^0.9917R²0.9981), "Δ" (fixed at 16 degrees: 0.4999x^1.062R²0.9881) and(fixed at 0 degree: y 0.3138x^1.4154R²0.7939). The data from the 4 experiments were averaged. Error bars (errorbars) represent the average error with 95% confidence. The experimental data show that: the rotating bristle tufts experience 1.6 times more interproximal residence time than the angled, fixed bristle tufts; the rotating bristle tufts experience 2.7 times more interproximal residence time than the vertical, fixed bristle tufts. More interproximal residence time translates into better cleaning between teeth.

Referring to fig. 2 and 3, the structure and manufacturing method for rotating the element 16 will be described. The element 16 comprises at its lower end an integral bearing portion 18, which has a cylindrical shape and is rounded at its ends. The support portion 18 can be formed either from a portion of the material from which the element 16 is melt-fabricated or by molding the support portion in a separate molding operation.

Such molding operations would use high flow materials such as ExxonEscorene polypropylene PP-1105 or FINA polypropylene 3824. It is important to gate from both sides during the molding operation and to have a very low package pressure. Preferably, there is a cut-out in the member 16 to secure the support portion 18 to the member 16. If the support 18 is molded separately and then secured to the member 16, an adhesive may be used instead of a cut to secure the member 16 and the support 18 together.

An example of a particular molding operation is the molding of ExxonEscorenePolypropylenePP-1105 using a 90TonToshiba InjectionMoldingmachine. The temperature curves are a barrel temperature of 350F (barreltemperture), a rear temperature of 350F (reartemperature), a front temperature of 405F (fronttempertemperture) and a nozzle temperature of 390F. The molding temperature is preferably about 90F and an 1/16 inch nozzle is used. The fill time was 0.25 seconds, the forward spiral time was 3.75 seconds, the spray time was 4.00 seconds, and the cool down time was 15 seconds. The peak hydraulic pressure was 250 psi.

Head 12 is actually constructed of a top member 22 and a bottom member 24. These two components are formed in separate molding steps in which component 22 is integrally molded with the handle. The element 16 is inserted in a hole 25 in the top member 22 and finally supported at its ends in the position shown in the figures. The aperture 25 includes a support socket 20 which captures the support 18. Preferably, a viscous substance, such as a quantity of food grade grease, is inserted into the bearing socket 20 to provide some resistance to rotation of the element 16, thereby preventing the element from jumping back and forth loosely. Finally, member 24 is secured to member 22 to retain support 18 in socket 20. Member 24 can be secured to member 22 by, for example, snap features (not shown) or heat welding. Alternatively, the member 22 can be injection molded in its place.

In another method of manufacture, the two members 22, 24 of the head are injection molded as a unitary head (and handle) around the bearing 18. Higher melting temperature materials are required for the element 16 and the support portion 18 so that they do not soften/melt during the injection molding of the head/handle. Element 16 is capable of cutting after the toothbrush is completed by rotating the element back and forth so that a portion of the plastic of the brush head is released when the rotation interferes with the element.

The arrangement described above allows the element 16 to be rotated back and forth about only one axis 26, which is preferably substantially perpendicular to a long axis of the element 16. Preferably, the element 16 can be rotated 30 degrees on both sides of the vertical direction. The top of the hole 25 limits the amount of rotation of the element 16. It should be noted that there is no spring force or other force returning the element 16 to its original position, so that the element can end up in an infinite number of positions within a 60 degree range of freedom of movement at the end of the brushing process.

Alternatively, the bearing portion 18 may be made spherical. The use of such a spherical bearing would only allow rotation of the element 16 about only one axis, as shown in figure 2, with the head 12 engaging the opposite side of the element 16, thereby limiting rotation about only one axis.

Referring now to fig. 4 and 5, another tooth cleaning element will be described. Element 30 includes a tooth cleaning portion 32 which may be a bristle tuft or an integral plastic or rubber blade. A hinge 34 (e.g., a living hinge) made of a flexible plastic or elastomer is injection molded onto the cleaning portion 32. The material from which the hinge 34 is made must be carefully selected because if it is too soft, the retention of the element 16 is too poor and if the material is too stiff, the hinge will not be sufficiently flexible. The rubber chain is preferably made of DYNAFLEX thermoplastic rubber compound G2780 or G2711 from GLS and can be injection molded under the above conditions. The living hinge allows the cleaning section 32 to rotate substantially about only one axis 36, the axis 36 being as described above, preferably substantially perpendicular to a long axis of the section 32. The resistance to rotation increases as the portion 32 moves away from a position perpendicular to the top surface of the toothbrush head. A toothbrush head 38 having an integral handle (not shown) is injection molded around the base of a living hinge 34 to retain living hinge 34 in the toothbrush head (as shown in fig. 4).

Claims (12)

1. A toothbrush head, comprising: a top member having an aperture, said aperture comprising a support socket; a tooth cleaning element extending from the top member of the toothbrush head rotatable about an axis, wherein the tooth cleaning element includes a first portion for contacting teeth and a second portion, wherein the second portion is disposed in the support socket, and wherein the support socket is covered by a bottom member of the toothbrush head opposite the top member of the toothbrush head.

2. A toothbrush head according to claim 1 further comprising a plurality of tooth cleaning elements rotatable about an axis.

3. A toothbrush head according to claim 2 further comprising a second plurality of non-rotatable tooth cleaning elements.

4. A toothbrush head according to claim 1 characterised in that the first part of the tooth cleaning elements comprises an elastomer.

5. A toothbrush head according to claim 4 characterised in that the tooth cleaning elements are in the form of blades.

6. A toothbrush head according to claim 1 characterised in that the second part is in the form of a bearing portion.

7. A toothbrush head according to claim 1 characterised in that the tooth cleaning elements have a range of rotation of less than 60 degrees.

8. A toothbrush head according to claim 7 characterised in that the range of rotation is limited to a portion of the head.

9. A toothbrush head according to claim 3 wherein the plurality of tooth cleaning elements rotatable about an axis and the plurality of second tooth cleaning elements are arranged alternately adjacent one edge of the head.

10. A toothbrush head according to claim 9 characterised in that the plurality of tooth cleaning elements is 4.

11. A toothbrush head according to claim 9 wherein the plurality of rotatable tooth cleaning elements and the plurality of second tooth cleaning elements are alternately arranged adjacent two edges of the toothbrush head.

12. A toothbrush comprising a head according to claim 1 and a handle attached to the head.