Toothbrush

A toothbrush head is provided with a plurality of separate cleaning areas. The distal end and the proximal end of the head include cleaning elements mounted to generally non-movable bases. The central portion of the head includes resilient pods carrying cleaning elements in such a manner that the cleaning elements are capable of bending away from their initial position and then returning to their initial position. In another aspect of the invention the pods are made as a separate unitary subassembly wherein the cleaning elements are bristles in an IMT procedure. The unitary subassembly is secured to the remainder of the cleaning head of the brush during the molding operation of the remainder of the head and the handle. In this aspect of the invention non-movable bases may be provided or may be omitted.

BACKGROUND OF THE INVENTION

The present invention relates to manually held and operated toothbrushes having flexibly mounted bristles. A number of approaches have been taken in the prior art to provide flexibility to the bristles during use of a toothbrush. U.S. Pat. No. 5,970,564, for example, discloses a toothbrush having an elastomeric ridge wherein there is a center array of bristles and there is a side array of bristles mounted in elastomeric boots. A number of patents disclose a toothbrush head having sets of bristles, each of which is mounted to a non-rigid or elastic support element. Examples of these approaches are found in U.S. Pat. Nos. 1,770,195, 2,244,098, 6,161,245 and 6,311,360 and in French Patent No. 38440.

It would be desirable if a toothbrush could be provided having various cleaning elements such as bristles with different degrees of flexible mounting.

SUMMARY OF THE INVENTION

An object of this invention is to provide a toothbrush having the head separated into different cleaning areas which differ from each other in the flexible mounting of the cleaning elements.

A further object of this invention is to provide such a toothbrush wherein some of the cleaning areas have the cleaning elements mounted on a relatively fixed or non-movable base while other cleaning areas are mounted on a flexible or elastic pod.

A still further object of this invention is to provide techniques for improving the manufacturability of toothbrushes such as indicated above or toothbrushes having only flexibly mounted cleaning elements.

In accordance with this invention the toothbrush head is divided into a plurality of separate cleaning areas. These areas include at least one and preferably two areas wherein the cleaning elements are mounted to a base with other areas having the cleaning elements mounted to pods wherein the pods have a greater degree of movability than do the bases. The pods are resilient so that during use the cleaning elements could be moved from their initial position and then returned to the initial position.

The pods may be formed from a narrow or small diameter beam extending from the body of the toothbrush head to a cleaning element support pad. Preferably the small diameter beam is enclosed in elastic material.

In a preferred practice of the invention a relatively non-movable base is located at each of the distal and proximal ends of the toothbrush head with at least two elastic pods mounted between the two bases. These various cleaning areas are separated from each other by channels extending completely across the head in a transverse direction.

In accordance with a further aspect of this invention the pods are formed utilizing an IMT process where the bristles are introduced into the mold cavity into which a plastic material is injected. As the injected material cools off, it permanently traps the bristles to form a brush. In order to achieve functional flexibility and proper tuft retention, materials are used to create a pod of mushroom shape by forming a stem and a plate to which the bristles would be secured. The pods are interconnected at the stems to form a first subassembly for making the toothbrush. This subassembly may then be attached to the bulk of the toothbrush, which includes the remainder of the head and the handle, by being overmolded with an entire toothbrush handle during a second injection cycle. As a result, the entire handle could be formed at normal speeds because the IMT process is initially isolated to a smaller material shot size.

DETAILED DESCRIPTION

FIGS. 1-4illustrate a toothbrush10in accordance with one aspect of this invention. As shown therein toothbrush10includes an elongated hand-held handle12with a head14connected to and extending from the handle. The head14is divided into a plurality of separate cleaning areas which are spaced from each other. As illustrated the cleaning areas include a base16located at the distal end of the head14and projecting outwardly from the main body portion30of the head. Base16includes at least one and preferably a plurality of cleaning elements18. Head14further includes a base or supporting member20at the proximal end of head14. Cleaning elements18also extend outwardly from base20.

Mounted between the cleaning areas which incorporate bases16and20are a pair of pods22,24. Each pod is provided with at least one and preferably a plurality of cleaning elements26. As later described the pods22,24have a greater degree of movability than do the bases16,20. In the preferred practice of the invention the pods22,24are resilient members so that the pod cleaning elements add a motion range beyond the cleaning elements18which are generally static or non-movable. Preferably, because the various cleaning elements are separated from each other such as by channels28which extend completely across head14in a transverse direction and because of the elastic nature of pods22,24, the cleaning elements26are capable of 360 degrees rotation about the vertical axis of each individual pod. The angle of the bend is dictated by the ability of the material to bend.

Toothbrush10thus provides a head14wherein the front (distal end) and the back (proximal end) areas are in a relatively fixed position and wherein the cleaning elements, such as bristle strands,18do not have any extra degree of motion. The middle portion of head14, however, has two areas of cleaning elements26,26which are capable of 360 degree rotation.

As best shown inFIG. 4the head14includes a main body portion30which supports the bases and pods. Body portion30and bases16and20are preferably made from conventional hard plastic materials, such as polypropylene, commonly used in the making of toothbrush handles and heads. Pods22,24, however, are made so as to be resilient. In the preferred practice of this invention, the resiliency of pods22,24is achieved by providing a thin diameter beam32which extends from the main body portion30of the head of the toothbrush. Beam32is joined into the bottom of a thin pad or plate34which provides a support area onto which the cleaning elements26are affixed. The manner of mounting the cleaning elements26to the support pads34can be achieved utilizing various cleaning elements, such as bristles and other cleaning materials, in known attachment methods.

The desired flexibility or resiliency of the pods22,24is enhanced by enclosing the thin beams32in elastic material36which could be acquired during the multi-injection molding process. The elastic material36serves as a rubber band by returning the beams32to their original form or initial position. This return action creates an active motion in the opposite direction of the beam bend which aids in the cleaning of teeth by introducing extra brushing strokes.

As best shown inFIGS. 1,2and4the pods22,24include a widened portion disposed toward the body30. The support pads34are also widened. Each pod has a narrow or reduced diameter central portion38longitudinally intermediate the length of each pod. Thus, each pod is of generally mushroom shape.

Beam32could be of any suitable shape such as having a cross-section which is circular, square or any other geometric shape that provides a thin dimension or thin diameter to the beam to facilitate the bendability of the beam. The elastomer36may be considered as a continuous layer of any suitable thickness which covers the entire central area of head14as illustrated so that both pods22,24are incorporated as part of the same elastic material. The portion of the head14which includes pods22,24may be formed as a separate subassembly similar to the subassembly later described with respect toFIG. 5-6.

Although the invention could be practiced with a single base and a single pod and could be practiced with the base having some, but a lesser degree of flexibility than the pod, the invention is preferably practiced wherein the base is generally static or non-movable. In addition, the invention is preferably practiced where there are a plurality of such bases and a plurality of pods. The drawings illustrate a preferred practice of the invention where there are a total of four separate cleaning areas with the pods being located in the central portion of head14. The invention is also preferably practiced where the cleaning elements comprise a plurality of bristles or strands on each base and each pod.

As illustrated inFIG. 3each base16and20and each pod22and24has a generally oval outer surface. The bases and pods are longitudinally aligned, but spaced from each other by the depressions or open areas which form the channels28. As also illustrated inFIG. 3the pods have a larger outer surface or cleaning element carrying surface than do the bases.

As shown inFIG. 2the terminal surfaces of the cleaning elements18and26are tapered so that the terminal surfaces of the cleaning elements18taper outwardly in a direction toward the center of head14while the terminal surfaces of cleaning elements26taper outwardly in a direction away from the center of head14. Thus, the highest points of each set of cleaning elements18and its adjacent set of cleaning elements26are generally disposed toward each other for each pair of base and pod16,22and20,24.

Any suitable form of cleaning elements may be used as the cleaning elements18and26in the broad practice of this invention. The term “cleaning elements” is intended to be used in a generic sense which could include conventional fiber bristles or massage elements or other forms of cleaning elements such as elastomeric fingers or walls arranged in a circular cross-sectional shape or any type of desired shape including straight portions or sinusoidal portions. Where bristles are used, the bristles could be mounted to tuft blocks or sections by extending through suitable openings in the tuft blocks so that the base of the bristles is mounted within or below the tuft block.

Using different cleaning materials as cleaning elements of the toothbrushes may yield different effects. In an attempt to provide better stain removal a rubber-like material or elastomer can be used in combination with conventional bristles or used by itself to “brighten/whiten” the teeth.

It is to be understood that the specific illustration of the cleaning elements is merely for exemplary purposes. The invention can be practiced with various combinations of the same or different cleaning element configurations (such as stapled or in-molded technology bristles, etc.) and/or with the same bristle or cleaning element materials (such as nylon bristles, spiral bristles, rubber bristles, etc.) Similarly, whileFIG. 2illustrates the cleaning elements to be generally perpendicular to the outer surface of head14, some or all of the cleaning elements may be angled at various angles with respect to the outer surface of head14. It is thereby possible to select the combination of cleaning element configurations, materials and orientations to achieve specific intended results to deliver additional oral health benefits, like enhanced cleaning tooth polishing, tooth whitening and/or massaging of the gums.

FIGS. 5-6illustrate a further aspect of this invention relating to techniques for forming the toothbrush. The toothbrush10A has the ability to provide flexible support for the bristles26A in designated areas. The flexibility is provided by designing the tuft holding areas34A as plates which in combination with the stems38A forms pods of mushroom shape. The mushroom stem38A is made flexible to allow the plate34A populated with bristles or cleaning elements26A to move in different directions while brushing, as described with respect to the flexible pods ofFIGS. 1-4.

FIGS. 5-6show the toothbrush10A and in particular the cleaning element or bristle carrying portion23of the head14A to be made utilizing an IMT process. As shown inFIG. 5the bristle or cleaning element carrying portion23forms an initial subassembly. This subassembly is made by introducing the cleaning elements26A into the mold cavity into which a plastic material is injected. As the material injected cools off it permanently traps the bristles or cleaning elements26A to form a brush or subassembly23.

To achieve a functional flexibility and proper tuft retention the portion of the bristle holding part or subassembly23which comprises the plates34A, stems38A and interconnecting support25is preferably a blend of polypropylene (PP) and soft TPE. Once the PP/TPE blend is combined with the bristles26A the subassembly23is formed. In an initial independent IMT step the subassembly23is then overmolded with an entire toothbrush handle12A and head14A during a second injection cycle to form the completed toothbrush10A shown inFIG. 6. If desired or required the entire handle12A and head14A absent the subassembly23could be made first and the subassembly or bristle retaining portion23made second.

Other IMT toothbrushes that have bristles attached to the bulk of the handle as known in the prior art are difficult to make because of the slow injection speed needed to fill the head of the toothbrush. The present invention permits the making of an entire handle at normal speeds by isolating the IMT process for making subassembly23to the smaller material shot size. Although a blend of PP/TPE is a preferred practice of this invention such blend is not required to make an IMT brush using the method of this invention. Similarly, the invention may be practiced using compatible materials to fuse the first and second shots so that the subassembly23created in one of the shots will be secured to the remainder of the toothbrush in the other shot. Thus, the two shots are mechanically trapped together to achieve essentially the same benefits as achieved by combining the subassembly23with the remainder of the toothbrush in a second injection cycle.

It is to be understood that the invention described inFIGS. 5-6could be practiced where all portions of the head14include the flexible mushroom sections without having less flexible base portions such as bases16and20ofFIGS. 1-4. Similarly, the subassembly two shot techniques ofFIGS. 5-6could be utilized in the embodiment ofFIGS. 1-4for forming the two or more central pods22,24as a single subassembly initially made separate from the remainder of the toothbrush head14. The final toothbrush would be made in a second injection molding process wherein the subassembly having interconnected pods22,24would be molded to the handle12and head14made of more rigid material.

As noted,FIG. 2illustrates the terminal surfaces of the cleaning elements18and26to be tapered in an up and down or zig zag manner.FIGS. 5-6show an alternative taper wherein the terminal surfaces form a smooth, gentle, concave shape. If desired, other shapes may be used such as a planar shape for the terminal surfaces or a convex shape as well as the zig zag or up and down shape shown inFIG. 2. Similarly, the terminal ends of the cleaning elements in theFIGS. 1-4embodiment, as well as those ofFIGS. 5-6, could have the various shapes such as zig-zag, convex, concave or planar.

AlthoughFIGS. 1-4and5-6illustrate a manually operated toothbrush, the invention may also be practiced where the head includes one or more power or electrically operated movable sections carrying cleaning elements. Such movable section may oscillate in a rotational manner or may oscillate linearly in a longitudinal direction with respect to the longitudinal axis of the head or may oscillate linearly in a lateral or transverse direction with respect to the longitudinal axis of the head. The movable section may oscillate in and out in a direction toward and away from the outer surface of the head. The movable section may rock back and forth with respect to the outer surface of the head. The movable section may rotate continuously in the same direction, rather than oscillate. Any suitable drive mechanism may be used for imparting the desired motion to the movable section. Where plural movable sections are used, all of the movable sections may have the same type and direction of movement, or combinations of different movements may be used.

FIG. 7illustrates a toothbrush10B which includes a power driven movable disc or section40having cleaning elements. The movable section40could be oscillated rotationally such as by using the type of drive mechanism shown in U.S. Pat. No. 5,625,916, or could move in and out using the type of drive mechanism shown in U.S. Pat. No. Re35,941, all of the details of both patents are incorporated herein by reference thereto. Alternatively, the other types of drives referred to above could move section40in other manners and directions. AlthoughFIG. 7shows movable section40to be at the distal end of the head, the movable section(s) could be located at any desired location on the head.