Toothbrush with bristle-mounting system for retarding bristle strain

A toothbrush includes an elongate body having a handle and a head formed with bristle assemblies each including elastic upper and lower boots on either side of an intermediate layer, an elastic collar extends through the intermediate layer from the lower boot to the upper boot, a tuft of bristles bound by a coupling, the tuft of bristles extends from the coupling in the lower boot through the collar and through the upper boot and therebeyond to a brushing extremity, the upper boot provides lateral elastic compliance between the upper boot and the tuft of bristles through the upper boot, the lower boot provides lateral elastic compliance between the lower boot and the coupling in the lower boot, and the intermediate layer pinches the collar against the tuft of bristles through the collar elastically retaining the tuft of bristles through the elastic collar to the elastic collar.

FIELD OF THE INVENTION

The present invention relates generally to toothbrushes and, more particularly, bristle-mounting systems designed to relieve bristle strain to extend bristle life.

BACKGROUND OF THE INVENTION

Toothbrushes are well known and commonly employed to maintain dental hygiene. Toothbrushes are routinely used daily or more often to brush teeth to remove food particles, plaque, and other debris from around the teeth and gums. Most dental hygiene professionals recommend brushing the teeth by moving the toothbrush in a reciprocal lateral direction with the toothbrush held in a general horizontal position during brushing to facilitate safe and efficient cleaning of the teeth and gums.

A standard toothbrush includes bristles mounted in a head. The head provides support for the bristles. The bristles are mounted on the toothbrush in an upright orientation to enable the brushing ends of the bristles to engage the teeth when the toothbrush is used to brush teeth. During the use of a toothbrush, the bristles inherently bend repeatedly. Following prolonged use, the repeated bending of the bristles causes the bristles to splay permanently outwards from the upward orientation and can cause some of the bristles to break where they bend at their attachment point to the head reducing bristle density, whereupon the toothbrush is discarded and replaced.

In the United States alone it is estimated that nearly a billion toothbrushes, representing more than 50 million pounds of waste, are discarded and end up in land fills every year. These toothbrushes are made from a combination of plastic, rubber, nylon, and a combination of plastic and cardboard for the packaging. These materials are largely not biodegradable. Therefore, they remain in landfills indefinitely. Furthermore, discarded toothbrushes often end up in the oceans, washed up on our beaches, or consumed by marine life. Accordingly, there is a need in the art for a toothbrush having a bristle-mounting system that retards bristle bending relative to the head for retarding bristle strain and breakage for prolonging bristle competency and bristle life for, in turn, prolonging the useful life of the toothbrush for reducing the adverse environmental impacts that discarded toothbrushes inflict on the environment.

SUMMARY OF THE INVENTION

According to the principle of the invention, a toothbrush includes an elongate body including a handle and a head formed with bristle assemblies. The bristle assemblies each include an upper elastic boot, a lower elastic boot, an elastic collar, an intermediate layer, and a tuft of bristles bound by a coupling. The upper elastic boot and the lower elastic boot are formed on either side of the intermediate layer. The elastic collar extends through the intermediate layer from the lower elastic boot to the upper elastic boot. The coupling is in the lower elastic boot. The tuft of bristles extends from the coupling in the lower elastic boot through the elastic collar and through the upper elastic boot and beyond the upper elastic boot to a brushing extremity. The upper elastic boot provides lateral elastic compliance between the upper elastic boot and the tuft of bristles through the upper elastic boot, the lower elastic boot provides lateral elastic compliance between the lower elastic boot and the coupling in the lower elastic boot, and the intermediate layer pinches the elastic collar against the tuft of bristles through the elastic collar elastically and pivotally retaining to the elastic collar the tuft of bristles through the elastic collar. The intermediate layer is formed with an inwardly-directed continuous edge against and surrounding the elastic collar between the upper elastic boot and the lower elastic boot, and is sufficiently rigid along a plane perpendicular relative to the elastic collar and the tuft of bristles through elastic collar to enable the inwardly-directed continuous edge to pinch the elastic collar against the tuft of bristles through the elastic collar. The upper elastic boot surrounds the tuft of bristles extending through the upper elastic boot. The lower elastic boot surrounds the coupling. The coupling is enclosed in the lower elastic boot. The upper elastic boot, the lower elastic boot, and the elastic collar are coaxial. The upper elastic boot, the lower elastic boot, and the elastic collar are integral to form a unitary elastic body.

DETAILED DESCRIPTION

Turning now to the drawings, in which like reference characters indicate corresponding elements throughout the several views, attention is first directed toFIG. 1illustrating toothbrush20including elongate body22having head24and handle26, and neck28therebetween. Elongate body22is fashioned of plastic, rubber, a combination thereof, or other similar material or combination of materials common in the art. With additional reference toFIGS. 2 and 3, head24supports bristles30. Bristles30are arranged in a cluster of tufts32of bristles30, i.e. bristle tufts32. Bristle tufts32are mounted on head24in an upright orientation to enable brushing ends or extremities34of the tufts30to engage the teeth when toothbrush20is used to brush teeth. Bristle tufts32are circular in cross section in this example.

InFIG. 4, which is a section view taken along line4-4ofFIG. 3, head24includes block40formed around internal frame or layer42, which together support bristle tufts32. Layer24is integral with head24, and block40encapsulates layer42. Block40is formed of an elastic material having inherent elastic properties of resilience and shape memory being inherently capable of returning to its original shape after being flexed or otherwise deformed when toothbrush20is used to brush teeth. The resilient material of block40is an elastomer, such as RTP 2700S-30A thermoplastic elastomer. Block40is molded over and around layer42. Cap44under block40and layer42defines the underside of head24. Cap44is part of head24. Cap44, formed of plastic or rubber, is affixed in place via adhesive or heat bonding, and can be overmolded onto, or formed integrally with, head24in alternate embodiments.

Each bristle tuft32and its assemblage with block40and layer42define a bristle assembly50. The bristle assemblies50are identical in every respect, operate identically to one another, and operate independently from one another. Accordingly, the details of one bristle assembly50of toothbrush20will now be discussed in detail, with the understanding that the ensuing discussion applies equally to each of the bristle assemblies50.

InFIG. 5, bristle assembly50, a bristle-mounting system, includes layer42, boots52and54, collar56, and tuft32of bristles30bound by coupling58, which in this example is a collar of metal crimped around the lower ends of bristles30. Boots52and54and collar are parts block40, are integral with block40, and are each, therefore, inherently elastic. Boot52is an upper boot, and boot54is a lower boot. Layer42includes upper surface60, lower surface62, and opening64. Opening64extends through layer42from upper surface60to lower surface62.

Bristles30are made of a material that is inherently resilient and flexible. In an illustrative embodiment, bristles30are made of a metal or metal alloy, as described in U.S. Pat. No. 6,442,785, the entire contents of which are incorporated herein by reference. Alloy bristles are flexible, resilient, hydrophobic, and can reach deeper. A preferred alloy exhibits inherent superelasticity at temperature ranges experienced under typical use of a toothbrush, such as NiTi alloy including 55.6% Ni and 44.4% Ti. In an alternate embodiment, bristles30can be fashioned of nylon or other material or combination of material commonly used in standard toothbrushes.

Upper boot52and lower boot54are on either side of layer42and opening64, are integral with bock40formed around layer42, and are carried or otherwise supported by layer42. Upper boot42, a circular, elongate collar, extends upright from upper surface60of layer42, and lower boot54, also a circular, elongate collar, extends downwardly from lower surface62of layer42. Upper boot52, lower boot54, and collar56are integral to form a unitary elastic body59. Collar56, integral with upper and lower boots52and54, extends through opening64of layer42from lower boot54to upper boot52. Upper boot52, lower boot54, collar56, and opening64are coaxial.

Layer42pinches collar56against tuft32of bristles30through collar56elastically and pivotally retaining tuft32of bristles30through collar56to collar56, according to the principle of the invention. Layer42is formed with inwardly-directed continuous edge42A that defines opening64. Edge42A is against and surrounds collar56between upper boot52and lower boot54. Layer42resides along plane P that is perpendicular relative to collar56. Layer42is integral with head24and is sufficiently rigid along plane P that is perpendicular relative to collar56and to tuft32of bristles30through collar56when tuft32of bristles30are at rest inFIG. 5to enable edge42A to pinch collar56, which is elastic, against tuft32of bristles30through collar30to captively retain tuft32of bristles30through collar56to collar56while at the same time enabling tuft32of bristles30through collar56to deform collar56and displace pivotally relative to opening64and to layer42when tuft32of bristles30flexes from an at-rest position inFIG. 5to flexed positions, such as inFIGS. 6 and 7. Tuft32of bristles30is in the at rest position when bristles30of tuft32are free from the influence of brushing, such as when toothbrush20is at rest and not in use. Layer42is formed of plastic or other material or combination of materials having the inherent properties of rigidity and resilience. Bristle assemblies50of toothbrush20share layer42.

Upper and lower boots52and54work independently from one another with respect to tuft32of bristles30and coupling56, respectively. As for upper boot52, upper boot52receives thereagainst tuft32of bristles30through upper boot52when tuft32of bristles30flex from the at-rest position inFIG. 5to an initially flexed inFIG. 6, and deflects laterally or otherwise to the side by tuft32of bristles30through upper boot52inFIG. 7when tuft32of bristles30flex beyond the initially flexed position inFIG. 6. Tuft32of bristles30flex from side-to-side in the directions of double arrowed line A inFIG. 5when toothbrush is used for brushing, at the same time causing upper boot52to elastically flex from side-to-side also in the directions of double arrowed line A inFIG. 5. Lower boot54is flexed by coupling58laterally or otherwise to the side inFIGS. 6 and 7when tuft32of bristles30flex from the at-rest position inFIG. 5. Coupling58displaces from side-to-side in the directions of double arrowed line B inFIG. 5when toothbrush is used for brushing, at the same time causing lower boot52to elastically flex from side-to-side also in the directions of double arrowed line B inFIG. 5.

Again, tuft32of bristles30is in the at rest position when bristles30of tuft32are free from the influence of brushing, such as when toothbrush20is at rest and not in use. Upper boot52, lower boot54, and collar54resume their original shapes when tuft32of bristles30is free from the influence of brushing, and elastically reset tuft32of bristles30to the at-rest position inFIG. 5. When tuft32of bristles30displaces laterally from side-to-side in the directions of double arrowed line A inFIG. 5, tuft32of bristles30through collar56acts on collar56causing collar56to elastically displace for providing pivotal movement of tuft32of bristles30through collar56relative to opening64and layer42. When tuft32of bristles30displace laterally to one side, upper boot52displaces elastically to one side by tuft32of bristles30through upper boot52, and lower boot54displaces elastically to the opposite side by coupling56in lower boot54. Accordingly, collar56displaces elastically enabling pivoting of tuft32of bristles30through collar, and upper and lower boots52and54displace elastically from side-to-side in opposite directions, upper boot52by tuft32of bristles30through upper boot52and lower boot54by coupling58in lower boot54, during brushing. Because tuft32of bristles30pivot relative to collar56as enabled by the inherent elasticity of collar56, bending of bristles30of tuft32of bristles30through collar56is inherently suppressed compared to if tuft32of bristles30was rigidly retained, thereby inherently extending the life of bristles30, in accordance with the principle of the invention.

Collar56resumes its original or at-rest shape inFIG. 5and in so doing acts on tuft32of bristles30through collar56, upper boot52resumes its original or at-rest shape inFIG. 5and in so doing acts on tuft32of bristles30through upper boot52, and lower boot54resumes its original or at-rest shape inFIG. 5and in so doing acts on coupling58in lower boot54, thereby resetting tuft32of bristles to its at rest position inFIG. 5when tuft32of bristles30are free from the influence of brushing. Because collar56deforms elastically side-to-side by tuft32of bristles30through collar56, upper boot52deforms elastically side-to-side by tuft32of bristles30through upper boot52, and lower boot54deforms elastically side-to-side by coupling58in lower boot54, when tuft32of bristles30flex between flexed (FIGS. 6 and 7) and unflexed (FIG. 5) positions inherently retarding bristles30from bending, straining and breaking at their connection point to collar56, which extends bristle30life and, accordingly, the useful life of toothbrush20.

In sum, toothbrush20includes elongate body22including handle26and head24formed with bristle assemblies50. Each bristle assembly50includes upper elastic boot52, lower elastic boot54, elastic collar56, intermediate layer42, and tuft32of bristles30bound by coupling58. Upper elastic boot52and lower elastic boot54are formed on either side of intermediate layer42. Elastic collar56extends through intermediate layer42, through opening64of intermediate layer42, from lower elastic boot54to upper elastic boot52. Coupling58is in lower elastic boot54. Tuft32of bristles30extends from coupling58in lower elastic boot54through elastic collar56and through upper elastic boot52and beyond upper elastic boot52to brushing extremity34. Upper elastic boot52provides lateral or side-to-side elastic compliance between upper elastic boot52and tuft32of bristles30through upper elastic boot54, lower elastic boot54provides lateral or side-to-side elastic compliance between lower elastic boot54and coupling58in lower elastic boot54, and intermediate layer54pinches elastic collar56against tuft32of bristles30through elastic collar56elastically and pivotally retaining to elastic collar56to tuft32of bristles30through elastic collar56. Intermediate layer42is formed with inwardly-directed continuous edge42A that defines opening64and that is against and surrounds elastic collar56between upper elastic boot52and lower elastic boot54, and is sufficiently rigid along plane P perpendicular relative to elastic collar56and tuft32of bristles30through elastic collar56to enable inwardly-directed continuous edge42A to pinch elastic collar56against tuft32of bristles30through elastic collar56. Upper elastic boot52surrounds tuft32of bristles30extending through upper elastic boot52. Lower elastic boot54surrounds coupling58. Coupling58is enclosed in lower elastic boot54. Upper elastic boot52, lower elastic boot54, and elastic collar56are coaxial. Upper elastic boot52, lower elastic boot54, and elastic collar56are integral to form unitary elastic body59, which is a sub-body or sub-part of block40.

The present invention is described above with reference to illustrative embodiments. However, those skilled in the art will recognize that changes and modifications may be made in the described embodiments without departing from the nature and scope of the present invention. Various further changes and modifications to the embodiment herein chosen for purposes of illustration will readily occur to those skilled in the art. To the extent that such modifications and variations do not depart from the spirit of the invention, they are intended to be included within the scope thereof.