WO2001012013A1

WO2001012013A1 - Toothbrush and method for making a tuft of bristles usable in a toothbrush

Info

Publication number: WO2001012013A1
Application number: PCT/US2000/022377
Authority: WO
Inventors: Casper Wen-Tien Chiang; Yan Feng; Edgardo Gotangco Zapanta; Donna Beals; Michael F. Roberts; Bradley Castillo; Gary Lim; Joseph E. Tungol; Andy Yang
Original assignee: Gillette Canada Company
Priority date: 1999-08-17
Filing date: 2000-08-15
Publication date: 2001-02-22
Also published as: AU6775000A

Abstract

A toothbrush (94) includes a handle (96), a head (92) extending from the handle (96) and a tuft of bristles (88) which are joined together at a based end of the bristles and secured to the head (92) at the base end. The tuft has a width (A) and a length (B). A ratio of the width to the length (A/B) is about 0.25 or less.

Description

TOOTHBRUSH AND METHOD FOR MAKING A TUFT OF BRISTLES USABLE IN A TOOTHBRUSH The invention relates generally to the field of oral care, and in particular to toothbrushes. The invention also relates to a method of making a tuft of bristles which are usable in a toothbrush.

In a traditional manufacturing process for making toothbrushes, a tuft of bristles is "picked" from a large supply of pre-cut bristles. The tuft of bristles is then stapled to a head of a preformed handle/head of a toothbrush. The free ends of the bristles are end-rounded and then the toothbrush is packaged for shipment. A more recently developed process for making toothbrushes requires that the picked tuft is heat- fused at one of its ends to melt the bristle ends together and thus secure the bristles together. A large number of fused tufts are then placed in a toothbrush handle head mold of an injection molding machine, with the fused ends of the tufts protruding into the mold and the remaining portion of the tuft being located outside of the mold. Molten plastic is next injected into the mold cavity. When the plastic solidifies, it secures the fused ends of the tufts to the head of the just-formed toothbrush. In this process, the bristles can be end-rounded either before or after they are secured to the toothbrush head.

In both of the toothbrush manufacturing processes described above, the variation allowed in the dimensions of an individual tuft in the two axes of the tuft which are perpendicular to each other and the long axis of the bristles has been limited. For example, traditional tufts are round in shape, and for those tufts which are other than round in shape, the dimension of the tuft along a first axis which is perpendicular to the long axis of the bristles will typically be no greater than two to three times the length of a dimension of the tuft along a second axis which is perpendicular to the first axis and the long axis of the bristles. Such a limitation on the dimensions of a tuft reduces the variety of tuft shapes which can be incorporated into a toothbrush, thus inhibiting the design of a toothbrush which otherwise might provide improved cleaning of the teeth. A further drawback with currently known methods of making toothbrushes is that the only characteristic of the bristles within a tuft which varies from one bristle to another is bristle length. Other characteristics of the bristles within a tuft, such as material, color, gray scale, surface characteristic and cross-sectional shape, do not vary. As a result, the visual appearance and cleaning effectiveness of tufts, and thus toothbrushes, is correspondingly limited.

A still additional restriction in current toothbrushes and their manufacture, is that the positioning of a bristle within a tuft relative to another bristle in that tuft is completely random. This is due to the fact that all of the bristles in a tuft are typically "picked" at one time in a single operation. Not being able to control the positioning and/or orientation of a bristle in a tuft relative to one or more other bristles in the same tuft restricts the capability of controlling tuft visual appearance and cleaning ability.

U.S. Patent No. 4,366,592 which issued on January 4, 1983 to Bromboz, discloses brushes and the method of making the same by first forming a strip embodying a backing sheet with bristles disposed on one face thereof in parallel relation to each other. Ends of the bristles project outwardly from one longitudinal edge of the strip. The strip is formed into a predetermined shape and then the bristle ends are secured in a base. Finally, the backing sheet is removed from the bristles.

The present invention is directed to overcoming one or more of the problems set forth above. Briefly summarized, according to one aspect of the present invention, a toothbrush includes a handle, a head extending from the handle and a tuft of bristles which are joined together at a base end of the bristles and secured to the head at the base end. The tuft has a width and a length. A ratio of the width to the length is about 0.25 or less.

The toothbrush described in the previous paragraph includes a tuft having a relatively small width to length ratio not disclosed in the prior art. Such a tuft expands the available tuft shapes available to toothbrush designers, thereby allowing a greater variety of toothbrush bristle patterns.

According to another aspect of the invention, a toothbrush includes a handle, a head extending from the handle and a tuft of bristles which are joined together at a base end of the bristles and secured to the head at the base end. One of the bristles has a characteristic that is different from that characteristic of another one of the bristles, the characteristic being selected from the group consisting of material, color, gray scale, surface characteristic and cross-sectional shape.

By providing a toothbrush with a tuft having bristles with different materials, colors, gray scales, surface characteristics and cross-sectional shapes, the appearance and cleaning ability of the tuft, and thus the toothbrush, can be enhanced.

According to a third aspect of the invention, a toothbrush includes a handle, a head extending from the handle and a tuft of bristles which are joined together at a base end of the bristles and secured to the head at the base end. A first one of the bristles is located in the tuft in a predetermined position and/or orientation relative to a second one of the bristles.

By enabling bristles to be located in predetermined positions and/or orientations within a tuft, the characteristics of the tuft, including appearance and tooth cleaning ability, can be controlled to a relatively fine degree based on the characteristics of the individual bristles. In accordance with a fourth aspect of the invention, a method of making a tuft of bristles for use in a toothbrush includes the step of positioning a group of individual bristles adjacent to each other such that the bristles are substantially parallel to each other in their longest dimension. The group of bristles has a width and a length. A ratio of the group width to length is about 0.25 or less. The method also includes the step of securing one portion of each bristle to one portion of at least one other bristle to form a tuft.

In other aspects, the invention features an oral brush that includes a body, and a tuft that includes a first set of bristles secured to the body and arranged in a first spiral pattern, and a second set of bristles secured to the body and arranged in a second spiral pattern. In one embodiment, the second spiral pattern surrounds the first spiral pattern. In another embodiment, the second spiral pattern defines a central area and the first plurality of bristles is disposed entirely in the central area of the second spiral pattern. In other embodiments, the bristles of the first spiral pattern extend from the body to a first height, and the bristles of the second spiral pattern extend from the body to a second height, the first height being greater than the second height. In some embodiments, the bristles of the first spiral pattern extend from the body to a first height, and the bristles of the second spiral pattern extend from the body to a second height, the first height being less than the second height.

In other embodiments, the bristles of the first spiral pattern have a first diameter, and the bristles of the second spiral pattern have a second diameter, the first diameter being greater than the second diameter. In one embodiment, the bristles of the first spiral pattern have a first diameter, and the bristles of the second spiral pattern have a second diameter, the first diameter being less than the second diameter.

In another embodiment, the path of the first spiral pattern is substantially parallel to the path of the second spiral pattern.

In one embodiment, the spiral tuft extends from the body to a first height, and the oral brush further includes a plurality of second tufts extending from the body to a second height. In some embodiments, the height of the spiral tuft is greater than the height of the second tufts. In other embodiments, the height of the spiral tuft is less than the height of the second tufts. In another embodiment, the spiral tuft includes a diameter and the second tufts comprise a diameter, the diameter of the spiral tuft being greater than the diameter of the second tufts.

In some embodiments, the bristles extend at an angle toward the spiral center of the spiral tuft. In other embodiments, the bristles extend at an angle away from the spiral center of the spiral tuft.

In other embodiments, the tuft includes bristles that include a first end secured to the body and a second end extending away from the body, the second ends of the bristles being dimensioned such that the tuft includes a concave brushing surface. In one embodiment, the second ends of the bristles are dimensioned such that the tuft includes a convex brushing surface. In some embodiments, the second ends of the bristles are dimensioned such that the tuft includes a substantially flat brushing surface.

In one aspect, the invention features an oral brush that includes a body, and a tuft secured to the body, where the tuft includes a first set of bristles arranged in a first spiral pattern defining a central open area, and a second set of bristles disposed within the central open area.

In other aspects, the invention features an oral brush that includes a body, and a tuft that includes a set of bristles extending from the body, the set of bristles being arranged in a spiral pattern such that the height of the bristles at the exterior of the pattern is greater than the height of the bristles at the interior of the pattern. In one embodiment, the spiral pattern defines a spiral path terminating at a center end point and an exterior end point, and the height of the bristles increases along the spiral path from the center end point to the exterior end point. In some embodiments, the spiral pattern defines a spiral path terminating at a center end point and an exterior end point, and the height of the individual bristles gradually increases along the spiral path from the center end point to the exterior end point. In another aspect, the invention features an oral brush that includes a body, and a tuft that includes a set of bristles extending from the body, the set of bristles being arranged in a spiral pattern such that the height of the bristles at the exterior of the pattern is less than the height of the bristles at the interior of the pattern. In one embodiment, the spiral pattern defines a spiral path terminating at a center end point and an exterior end point, and the height of the bristles decreases along the spiral path from the center end point to the exterior end point. In another embodiment, the spiral pattern defines a spiral path terminating at a center end point and an exterior end point, and the height of the individual bristles gradually decreases along the spiral path from the center end point to the exterior end point. In other aspects, the invention features a tuft that includes a set of bristles that includes individual bristles having a first end and a second end joined to the second end of an adjacent bristle, the second ends of the bristles terminating in a cup-like extension, in which the set of fused bristles is wound upon itself in the form of a spiral. The first ends of the bristles can extend toward the center of the spiral or the first ends of the bristles can extend toward the exterior of the spiral.

In still other aspects, the tuft includes a set of bristles that includes individual bristles having a first end and a second end fused to the second end of an adjacent bristle, in which the set of fused bristles is wound upon itself in the form of a spiral.

In another aspect, the invention features a method of using an above-described oral brush that includes brushing the teeth of a mammal with the brush.

In another aspect, the invention features a method of making an above-described spiral tuft, where the method includes inserting a portion of the ribbon of bristles into a slit in a rod, and turning the rod such that the ribbon of bristles rolls upon itself to form a spiral tuft.

In other aspects, the invention features a method of manufacturing an oral brush that includes securing an above-described tuft to a body.

These and other aspects, objects, features and advantages of the present invention will be more clearly understood and appreciated from a review of the following detailed description of the preferred embodiments and appended claims, and by reference to the accompanying drawings.

Like reference numbers and designations in the various drawings indicate like elements.

FIG. 1 is a perspective view of a single bristle picker station; FIGS. 1A and IB are top views of a picking wheel showing various notched circumferences of the wheel;

FIG. 2 is a top view of a tuft manufacturing machine including a pair of bristle picker stations;

FIG. 3 is a partial side view of Fig. 2 along the direction of arrow X in Fig. 2;

FIGS. 4A-C are perspective views of three types of bristle tufts; FIGS. 5A-C are side views of three tufts each having a different top contour;

FIGS. 6A-B are perspective views of two tufts with the bristle ends processed in two different manners;

FIG. 7 is a looped bristle type of tuft; FIGS. 8A-C disclose steps for making round tufts; FIGS. 9A-D disclose steps for making round tufts and show a round tuft secured to a toothbrush head; FIGS. 10A-E discloses toothbrush heads with various types of tufts secured to the heads;

FIG. 11 discloses another apparatus for making tufts; and, FIGS. 12A-B disclose tufts made by the apparatus of Fig. 11.

FIG. 13A is a side view if a tuft manufacturing tool according to one embodiment of the invention.

FIG. 13B is a perspective end view of the tool of Fig. 13A FIG. 13C is a view taken in cross section along line C-C of Fig.

13 A, which includes a bristle ribbon inserted therein.

FIG. 13D is a side view of the tool of Fig. 13A and a bristle ribbon wound thereon.

FIGS. 14A-B are a side perspective view and a top view, respectively, of a spiral tuft according to one embodiment of the invention.

FIG. 15 A is a front side view of a bristle ribbon that includes bristles of two different heights.

FIGS. 15B and 15C is a side view and a perspective side view, respectively, of embodiments of tufts prepared from the bristle ribbon of Fig. 15 A. FIG. 16A is a toothbrush that includes one embodiment of the spiral tuft of Fig. 15B.

FIG. 16B is a side view of a toothbrush that includes another embodiment of the spiral tuft of Fig. 15B.

FIG. 17A is a front side view of two bristle ribbons layered on top of one another.

FIGS. 17B and 17C are a side view and a top view, respectively, of a tuft formed from the ribbons of Fig. 17A.

FIG. 17D is a side view of a toothbrush including the spiral tuft of Fig. 17B. FIGS. 18A-D depict a front side view of a bristle ribbon according to another embodiment of the invention, a side view of a tuft formed therefrom, a top view of the tuft, and a toothbrush that includes the tuft, respectively.

FIGS. 19A-C are top views of tufts according to other embodiments of the invention. FIG. 20A is a front side view of a bristle ribbon having bristles that include a cup like extension at the fused end of the ribbon.

FIG. 20B is a profile view of the bristle ribbon of Fig. 20A. FIGS. 20C-E are side views of tufts formed from the bristle ribbon of Figs. 20A and 20B.

Beginning with Fig. 1, a method and apparatus for manufacturing a tuft of bristles for use in a toothbrush will be described. A supply of bristles 10 are stored in a magazine 11. The bristles are, for example, preferably made of nylon or polyester. The bristles can also be made of polypropylene or a natural or synthetic material suitable for bristles. The bristles are preferably between about 12 to 37 mm long prior to being joined together, and have a preferable diameter of between about 0.1 to 0.25 mm. Preferably, the bristles are pre- end-rounded at the ends showing in Fig. 1. All of the bristles 10 are preferably identical in material, length, cross-section, color and/or gray scale. A pneumatically operated pusher 22 presses bristles 10 against one or more picking wheels 12 with a force of preferably between about 9 to 18 psi.

As shown in Figs. 1A and IB, the circumference of wheel 12 is notched with each notch capable of holding a single bristle 10. The shape of each notch is selected to hold a particular type of tuft. Although all of the notches on a wheel preferably have the same shape, the spacing between notches can vary to allow varied spacing between picked bristles. The wheels 12 in Figs. 1A and IB have notches which differ in shape between the two wheels, thus allowing each wheel to pick a different sized bristle.

Turning to Fig. 2, a pair of picking wheels 12 are shown and are rotated in the direction of arrows 23 at the same constant speed by a variable speed drive system (not shown). Wheels 12 are preferably about 3 inches in diameter and are rotated at between about 3 to 30 rpm. Bristles 10 being fed to a first one of picking wheels 12 can be different in material, length, cross-section, color and/or gray scale from bristles being fed to a second one of the picking wheels. When bristles 10 are pressed against wheels 12 by pushers 22, those bristles at a nip point 24 between the wheel and bristles are captured by the notches in the circumference of the wheel and carried in the direction of arrows 23. Wheels 12 contact the bristles just below the mid-point of the bristle length. A pair of pinch plates 26 for each wheel 12 contain bristles 10 in magazine 11 and prevent those bristles captured in the wheel notches from falling out of the notches once the captured bristles are rotated away from the supply of bristles. Wheels 12 and pinch plates 26 are preferably made of hardened steel or carbide for wear resistance.

As mentioned above, the notches on wheels 12 can have variable spacing between notches. This space can be very small to very large in size. Wheels 12 are constructed and rotationally aligned such that where the wheels nip together, the notches on one wheel face the spaces between notches on the other wheel and vice versa. As such, when wheels 12 are rotated, bristles 10 are "shuffled together" one after the other in a single layer at the nip between the wheels like a deck of cards. Because the spacing between notches is variable, a huge variety of bristle patterns of the bristles from the two wheels 12 can be obtained. For example, the bristles from each wheel can alternate in a one-to-one pattern, a two-to-one pattern, or any pattern desired. Further, any bristle in the finished tuft will be in a predetermined position and/or orientation relative to any other bristle in the tuft. Wheels 12 each carry their respective bristles to a nip of a pair of endless belts 13. Belts 13 are non-stretchable or are minimally stretchable, and are preferably made of plastic. The belts are rotated in the direction of arrows 28 by a pair of belt drive pulleys 14 which are powered by a variable speed drive system (not shown). A pair of belt tensi oners 16 maintain a desired tension on belts 13. Two pairs of belt guide rollers 30 are located at both ends of where belts 13 nip together. The belts 13 are driven by pulleys 14 at the same constant speed which may be the same as, slower than or faster than the speed at which wheels 12 are rotated. At an end of the nip between belts 13 which is adjacent wheels 12, the belts capture the bristles from the nip of wheels 12 and carry them in the direction of arrow 28. The mid-point of where belts 13 contact bristles 10 is just above the mid-point of the bristle length. If belts 13 are moving faster than wheels 12, bristles 10 will have their spacing increased on the belts. If belts 13 are moving the same speed as wheels 12, bristles 10 will maintain their spacing on the belts. If belts 13 are moving slower than wheels 12, bristles 10 will have their spacing compressed on the belts. The bristles are preferably parallel to each other in their longest dimension at this point.

It should be noted that although only two wheels 12 are disclosed for feeding two types of bristles to belts 13, additional wheels and belts can be added to feed additional types of bristles into belts 13. For example, an additional pair of belts (not shown), fed by an additional one or two picker wheels (not shown), would feed an additional one or two types of bristles to the nip point between wheels 12. These additional belts would be located above wheels 12 while the bristles being carried by these belts would have the majority of their length protruding below the additional belts. Wheels 12 would have spaces between their notches, which spaces would line up with each other, wherever the bristles from the additional belts were being introduced between wheels 12. A pair of belt guide plates 15 are in contact with belts 13 on either side of where the belts nip together. Each plate 15 is divided up into four sections A, B, C and D which can each be independently positioned closer to or further from the belt nip. By adjusting the position of each of the sections of plates 15, the pressure with which belts 13 nip bristles 10 can be adjusted in four zones of the nip between the belts. Preferably, the sections of plates 15 are positioned so that the nip pressure in zones A and D are relatively higher than the nip pressure in zones C and D. The reason for this pressure gradient will be explained below with reference to Fig. 3.

Fig. 3 is a partial side view of Fig. 2 along the direction of arrow X in Fig. 2. Only bristles 10. the lower wheel 12 from Fig. 2 and the upper belt 13 of Fig. 2 are shown in Fig. 3 along with several new elements. Zones A, B, C and D as described above are also shown. The nip pressure of belts 13 in zone A is relatively high in order to secure bristles 10 and carry them away from wheels 12. In zone B the belt nip pressure is lowered so that a shaping element 32 (not shown in Fig. 2) can move some or all of bristles 10 along their long axis to provide a contour to the finished tuft. Element 32 is rotated in the direction of an arrow 34 at the same speed with which the bristles are traveling. Element is also moved up and down by a cam mechanism (not shown) in the direction of arrow 36. This rotation and translation of element 32 moves the bristles axially and provides the pattern shown in Fig. 3. Of course other types of shaping elements could be used to impart different contours to the bristles.

A resistive hot air blower 38 includes a fan 40 which draws air into the blower and blows the air past an electrically resistive heating element 42 to heat the air to preferably well above the melting temperature of the bristle material. The heated air then passes through a duct 44 and is blown onto a portion of 46 of bristles 10 to fuse the bristles together at that portion. It is preferable that hot air be blown onto portion 46 from both sides of the ribbon to speed fusing together of the bristles. The fused together bristles result in a bristle ribbon 49. Portion 46 of bristles 10 could alternatively be fused together by ultrasonic or laser welding, or adhered together by application of an adhesive and or a resin (synthetic and/or natural) to both sides of portion 46. A cutter 48 then trims away the portion of bristles 10 from ribbon 49 which are below fused portion 46. Alternatively, cutter 48 can trim away the lower portion of the bristles prior to the bristles being fused together by blower 38 (version not shown in drawings). In this version, the relative position of blower 38 and cutter 48 would be reversed, placing the cutter upstream of the blower. Blower 38 in this version blows hot air directly from below and onto the severed ends of the bristles.

A second reciprocating cutter 50, which is reciprocated in the directions of an arrow 52, periodically cuts through fused portion 46 of the bristles to cut a tuft of bristles 54 free from ribbon 49. Tufts 54 are transported further in the direction of arrows 28 by pairs of nip rollers (not shown) for further processing. It should be noted that blower 38, and cutters 48, 50 are not visible in Fig. 2 because they are below plates 15.

With reference to Figs. 4A-C, tufts 54a-c are shown. All of these tufts have flat contours on top contrary to the rounded top contour of tuft 54 in Fig. 3. The end rounded ends 56 of the bristles are visible in Figs. 4A-C. Regarding Fig. 4A, it is preferable that for tuft 54a, a ratio of the width to length "A/B" is about .25 or less. In Fig. 4B, a pair of tufts have been fused together to form a tuft 54b which is twice as wide as tuft 54a. The pair of tufts can be fused together by first aligning the tufts and then subjecting them to heat via impinging hot air, a laser or ultrasonic waves on portions 46 of the two tufts. Alternatively, the two tufts can be secured together with an adhesive and/or resin. In Fig. 4C, tuft 54c is made up of three tufts which have been secured together. Note that a middle tuft 58 is taller than the two outer tufts. This displays that any number of three dimensional contours for the finished tuft can be obtained by controlling the contour and bristle length of the bristle ribbons.

Alternatively to fusing together two or more tufts after severing the tufts from the bristle ribbon 49 as in 4B and C above, two or more bristle ribbons can be fused together first and then have individual tufts severed from the ribbon. This is accomplished by bringing two or more bristle ribbons together in a desired alignment after each ribbon has been separately fused at its own portion 46, and then fusing together portion 46 from each of the ribbons by any of the fusing methods discussed above (i.e. ultrasonic, adhesive, resin). Then individual tufts 54 are cut away from the multi-layer bristle ribbon to form multi-layer tufts.

Turning to Figs. 5A-C, three tufts, each having a different top contour, are displayed. Tuft 54a was discussed in the previous paragraph while tuft 54 was disclosed during the discussion of Fig. 3. Tuft 54d has a "N" shaped top contour. As shown in magnified portions 60, 60a and 60d of the top portion of some of the bristles in each of the tufts, bristles 10a and 10b are in an alternating pattern. Bristles 10a were fed from one picking wheel 12 (Fig. 2) while bristles 10b were fed from the other picking wheel. As mentioned above, bristles 10a can differ from bristles 10b in material, length, cross-section, color and/or gray scale. Although a one to one alternating pattern of bristles 10a and 10b is shown, any pattern of bristles may be formed based on the notch and space arrangement on the periphery of picker wheels 12. For example, there could be two 10a bristles for every one 10b bristle.

Referring to Figs. 6A and B, multi-layer tufts 54e and 54f, ends 62 of a middle layer of bristles 64 have been processed into a "micro-pick" form. This processing is done by (i) heating ends 62 to near their melting temperature, (ii) clamping a small portion of ends 62 with a bar clamp (not shown), (iii) pulling the bar clamp away from the bristles in the direction of the long axis of the bristles to cause ends 62 to "neck down", (iv) cooling bristle ends 62, and (v) cutting free the small portion of ends 62 which are secured within the clamp. Tuft 54f of Fig. 6B includes a "micro-hook" at bristle ends 66. This micro-hook is formed by a similar process used to form the micro-pick with one additional step. The step occurs just before cooling step (iv) described above and consists of rotating the clamp about 180 degrees to bend bristle ends 62 as shown on Fig. 6B. The micro-pick and micro-hook provide enhanced cleaning near the interproximal zones of teeth under the gum line (sub-gingival), each providing a different mouth feel. Referring to Fig. 7, a looped bristle type of tuft 68 is disclosed. Tuft

68 is formed by heat fusing a second portion 70 of bristles 10 together, portion 70 being located near the end of the bristles opposite the end near which portion 46 is located (see Fig. 46). The bristles are then bent in half to align fused portions 46 and 70 and adjacent each other. Finally, portions 46 and 70 are heat fused together. Looped bristle tuft 68 provides improved stiffness and wear resistance. As a further optional processing step, the looped portion of the bristles can be heated to near their melting temperature and then pressed flat between two plates in order to flatten the looped portion of the bristles (not shown in drawings).

Turning to Figs. 8A-C, a process for forming a round tuft from a tuft cut from bristle ribbon will be described. In Fig. 8 A a single layer tuft 72 is disclosed which has a "Length", a bristle height "HI" at the left end and a bristle height "H2" at the right end (the bristles on the right portion of the tuft above portion 46 are not shown). This arrangement results in a sloping contour of the bristles. In Fig. 8B tuft 72 is rolled up on itself to form a round tuft. Tuft 74 results if end "H2" is on the outside of the round tuft and end "H2" is on the inside (a concave tuft). Tuft 78 results if tuft 72 had a flat contour in that H1-H2 (a flat topped tuft). After tuft 72 is rolled up, portion 46 is again heat fused to secure portions 46 of the bristles together, thus locking the tuft into its rounded shape. In Fig. 8C, three oblong tufts 80 are disclosed. An oblong tuft is obtained by partially flattening a round tuft, such as tuft 78, prior to heat fusing portion 46, and then causing portion 46 to be heat-fused together.

Figs. 9A-C are similar to Figs. 8A-C except that Fig. 9A discloses a double layer tuft 82. Tuft 82 has a shorter layer of bristles 84 behind which are a relatively longer layer of bristles 86. Although the two layers have similar contours, this is not required. The resulting tufts 88 and 90 have two independent topographies which are interpenetrating within each other.

Referring to Fig. 9D, the right tuft of three tufts 88 is shown anchored to a toothbrush head 92 of a toothbrush 94. Only one tuft 88 is shown secured to head 92 for simplicity, but an actual toothbrush would typically have a large number of tufts secured to the head. Toothbrush 94 can be made by the following process which is generally understood by those skilled in the art and which is disclosed in U.S. Patent No. 5,609,890 which issued on March 11, 1997. Tuft 88 along with other tufts of a similar nature are inserted into respective apertures in a metal insert bar. The insert bar is then secured to a first mold half of an injection molding machine such that fused ends 46 project into the mold cavity. The mold is then closed to secure the first mold half to a second mold half. Fused ends 46 of the tufts are located just within the mold cavity with the non- fused portions of the bristles bring located outside of the mold cavity.

Polypropylene is then injected into the mold cavity to form a handle 96 with integral head 92. The polypropylene is then cooled at which point the toothbrush is removed from the mold. The cooled, hardened polypropylene secures fused ends 46 of the tufts to head 92 of toothbrush 94. Optionally, the toothbrush can be moved to a second injection molding station to apply a rubber to portions of handle 96. A thermoplastic elastomer (rubber) is injected into the second mold after which the elastomer is cooled and the finished toothbrush is removed from the mold. The toothbrush is then packaged. Figs. 10A-E disclose toothbrush heads and portions of integral handles with tufts secured to the heads. These tufts have not been rolled up, as described above, and thus have a very small width "A" when compared to their length "B". A ratio of width "A" to length "B" is preferably about 0.25 or less. Length "B" can be a straight line length, a curvilinear length (see Fig. 10(E) or a distance along the longest dimension of the tuft in which this tuft is bent to form two or more tuft sections which are at angles greater than zero to each other. These toothbrushes can be made by the process described above. All of these tufts can have from only one up to a very large number of layers of bristles in each tuft. In this case, the tuft's width/length ratio may be greater than .25. Fig. 10A is a side view of one embodiment of a toothbrush while

Fig. 10B is a top view of the same embodiment. Toothbrush 98 includes a handle 100 and a head 102. Tufts 104, as shown in Fig. 10A, alternate from a relatively taller tuft to a relatively shorter tuft. Fig. 10B shows that the tufts are all straight, and that they are all the same length except for the shorter tuft which is furthest from handle 100. The bristles in each tuft are preferably parallel to each other. Fig. IOC discloses a toothbrush 106 with a different tuft pattern. Here, four long straight rows of tufts 108 are oriented parallel to a long axis 109 of head 102. Two end tufts 110 are located at either end of head 102 and are curved in shape. In Fig. 10D, a series of identical, straight tufts are oriented on head 102 at an oblique angle to axis 109. Fig. 10E, discloses identical curved tufts 114 which arc across the width of head 102. Turning to Fig. 11, another embodiment of an apparatus for making tufts is disclosed. A large number of filaments F01, F02...F50 are passed through a feeding rack 120. Rack 120 brings the filaments into close proximity yet keeps them from crossing over by maintaining a preset gap between each of the filaments. This is accomplished by having separate apertures through rack 120 for each filament. The filaments then pass through a plastic welding means such as a heating element 122 which includes a scanning laser for periodically fusing (securing) the filaments together at, for example, location 124. Alternatively, an ultra-sonic or hot air system can be used to fuse the bristles together. A drive system 126 includes four nip wheels which engage the filaments and are rotated to move the filaments through the apparatus. The nip wheels do not need to contact all of the filaments because the filaments are fused together at this point. A punch press then severs a section of the filaments 130 free from the filaments with a die 143 which reciprocates in the directions of an arrow 134. A cutter (not shown) then cuts sections 130 into individual tufts of bristles 136. Turning to Figs. 12A-B, two tufts are disclosed which result when heater 122 (Fig. 11) is rotated such that it fuses the filaments at an oblique angle to the direction of travel (long axis) of the filaments. In Fig. 11, the filaments are fused in direction perpendicular to the long axis of the filaments. This results in tuft 138 (Fig. 12A) in which bristles 140 are at an oblique angle to their fused portions 142. Tuft 144 (Fig. 12B) is formed by placing two of tufts 138 together with one of tufts 138 having been flipped over. The two portions 142 are then fused together. These two tufts add further variety to the types of tufts which can be incorporated into a toothbrush.

Another process for forming a spiral tuft using tool 200, depicted in Figs. 13A-D, will now be described. Tool 200 includes a cylindrical rod 202 that includes a slit 204 located at one end 206 of the rod 202. Slit 204 extends through the diameter of rod 202 and is dimensioned to accommodate the lead end 208 of a bristle ribbon 210. Bristle ribbon 210 including fused portions 46 is inserted into slit 204 and the rod 202 is turned such that the ribbon winds upon itself, as shown in Figs. 13C-D. When the desired extent of bristle ribbon 210 has been wound upon itself, the ribbon 210 can be cut, if necessary, so as to separate the wound portion from the remaining extent of the ribbon 210, and then removed from the tool 200 by pushing the wound ribbon 210, now in the form of a tuft 220, in the direction of the slit end 206 of the rod 202, such that the tuft 220 slides off the rod 202. Tool 200 can be attached to a motor (not shown) to automate the winding operation. Referring to Figs. 14A and 14B, the resulting spiral tuft 220 includes bristles 212 arranged in a spiral pattern 222, which includes a spiral path 224 extending from an end point 226 near the spiral center 266, to an end point 228 at the exterior 268 of the spiral pattern. The diameter of the tool 200 used to wind the bristle ribbon 210 can influence the size of the open area 270 at the center 266 of the spiral tuft.

Referring to Fig. 15 A, a bristle ribbon 210 having a length "L" and including a first plurality of bristles 212 having a height "HI A" and a second plurality of bristles 214 having a height "H2A", where HI A is less than H2A, is shown. Bristle ribbon 210 can be rolled upon itself to form a spiral tuft 220A or 220B, as shown in Fig. 15B and 15C, respectively. Tuft 220A results if bristles 214 having height H2A form the exterior portion of the spiral tuft 220 A and bristles 212 having height HI A form the interior portion the tuft 220A. Tuft 220B results if bristles 212 having height HI A form the exterior portion of the tuft 220B and bristles 214 having height H2A form the interior portion of the tuft 220B. After bristle ribbon 210 is rolled upon itself to form a tuft 220, a portion 216 of bristles 212, 214 is again heat fused to secure portions 216 of the bristles together, thus locking the tuft 220 into its tuft shape. Alternately, the base of the tuft 220 can be heat fused or bonded with adhesive to lock the tuft 220 into its shape. The round tuft depicted in Figs. 15A-C can be formed into a variety of shapes including, e.g., an oblong tuft, in the manner described above.

In Fig. 16A, tuft 220 is shown secured to the head 262 of a toothbrush body 261 that includes a head 262, a handle 263, and additional tufts 230 of bristles to form toothbrush 260. The additional tufts 230 of bristles can include a variety of tufts including, e.g., spiral tufts (e.g., spiral tufts made from the above-described processes), hot tufted tufts, stapled tufts, and combinations thereof. The height H3 of tuft 220 (i.e., the height of the longest bristles of tuft 220) is even with the height H4 of the other tufts 230 of bristles. Bristles 212 having height HI A are depicted on tuft 220 with a dotted line to indicate their location at the interior of the spiral tuft 220.

Tuft 220 can also be dimensioned such that the height "H3" of tuft 220 extends above the height "H4" of the other tufts 230, as shown in Fig. 16B. Referring to Figs. 17A-D, a first bristle ribbon 232 is shown layered upon a second bristle ribbon 240. First bristle ribbon 232 includes bristles 234 having a height "H5" and a length "L2". Second bristle ribbon 240 has a length "L3" and includes bristles 242 having a height "H6". The spiral tuft 250, which can be formed by simultaneously winding bristle ribbon 232 and bristle ribbon 240 upon each other, includes two parallel spiral patterns 236, 246 defined by the bristles, 234 and 242, of bristle ribbons 232 and 240, respectively. The first spiral pattern 236 depicted with a solid line, includes bristles 234 of ribbon 232 and the second spiral pattern 246, depicted as a discontinuous line, includes bristles 242 of ribbon 240, as shown in Fig. 17C. The bristles 234 of spiral pattern 236 thus surround the bristles 242 of spiral pattern 246 at the exterior spiral layer of the tuft. Dotted line 251 on tuft 250 reflects interior bristles 242 having a relatively shorter longitudinal dimension than exterior bristles 234. The resulting tuft has alternating taller and shorter bristles along a linear path extending across the spiral. The resulting topography of the brushing surface of the tuft will vary according to the dimensions of H5 and H6, e.g., H5=H6, H5<H6 and H5>H6.

Ribbons 232 and 240 can also be wound upon each other in the opposite direction from that depicted in Fig. 17B such that bristles 242 of ribbon 240 form a spiral pattern that is parallel to and surrounds the spiral pattern formed by bristles 234 of ribbon 232.

In Fig. 17D, spiral tuft 250 is shown secured to the head 262 of a toothbrush 260. The height H7 of the relatively shorter bristles 242 of tuft 250 (as indicated by dotted line 251) is substantially the same as the height H4 of the other tufts 230 of bristles secured to the head 262, while the height of bristles 234 extends beyond the height of the other tufts 230.

The bristle ribbon can also include any number of bristles having a variety of diameters. A bristle ribbon can include bristles having a relatively smaller diameter, and bristles having a relatively larger diameter, e.g., 0.012 in. Useful bristles have diameters ranging from about 0.004 in to about 0.012 in. In some cases, the bristle ribbon includes bristles having diameters of about 0.008 in, about 0.0010 in, about 0.012 in, and combinations thereof.

The bristles can be rolled into a spiral tuft such that the larger diameter bristles are positioned at the exterior of the tuft and the smaller diameter bristles are positioned in the interior of the tuft, and vice versa. Similarly, a single tuft can include bristles having a variety of dimensions, shapes, compositions, surface characteristics, colors, and combinations thereof.

Other embodiments of the spiral tuft are shown in Figs. 8A-C, 9A-D, 18A-D and 19. In Figs. 18A-D, the spiral tuft 220 is wound from a bristle ribbon 210 that includes bristles 212 that gradually decrease in height from one end 284 of the bristle ribbon 210 to the other end 282 of the bristle ribbon 210. The spiral tuft 220 wound therefrom includes a series of bristles 212 that gradually decrease in height in the direction extending along the spiral path 224 from the spiral center 266 to the spiral exterior 268. Alternatively, the ribbon can be wound such that the resulting spiral tuft 220 includes bristles that gradually increase in height in the direction extending along the spiral path 224 from the spiral center 266 to the spiral exterior 268.

In addition, the center 266 of the spiral pattern 224 of the tuft 220 can define an open area 270, as shown in Figs. 19A-C. The open area 270 may be devoid of bristles, or may include additional bristles 272, tufts of bristles including the above-described spiral tufts 220, or a combination thereof. The tufts can be arranged in a variety of combinations. Referring to Fig. 19C, for example, a spiral tuft 220A having a relatively large cross-sectional diameter and a center space 270 can be combined with a second spiral tuft 220B having a relatively small cross- sectional diameter such that the second spiral tuft 220A is positioned entirely within the first spiral tuft 220A. In Fig. 19B, the center 270 of the spiral tuft 220 includes a second tuft 280 of bristles 272, e.g., a tuft of bristles formed by conventional tufting methods.

The spiral tuft can also be constructed from a ribbon that includes bristles 274 having ends 276 fused to the ends 276 of adjacent bristles 274, and formed into a cup-like extension 280, as shown in Figs. 20A-E. The degree of curvature in the cup-like 280 extension will influence the degree of bend exhibited by the bristles 274. In Fig. 20D, for example, the degree of curvature of the cup-like extension 280 is such that the bristles 274 are in a substantially parallel relationship to each other. If the cup-like extension 280 is facing the exterior of the tuft 220 during tuft formation, the resulting tuft 220 can have an outward flare at its free end 278 (i.e., the free ends extend outward toward the exterior of the spiral tuft), as shown in Fig. 20C. The cup-like fused ends 276 can cause the free end 278 the tuft 220 that is formed from the ribbon 210 to bend inward, toward the spiral center of the tuft 220 when wound with the cup-like extension 280 facing toward the interior of the tuft 220, as shown in Fig. 20E.

The invention has been described with reference to a preferred embodiment. However, it will be appreciated that variations and modifications can be effected by a person of ordinary skill in the art without departing from the scope of the invention. Other embodiments are within the claims. For example, the tufts can be formed into a variety of shapes including, e.g., an oblong tuft, as described above. In addition, the bristles of the ribbon, the ribbon and combinations thereof, can be dimensioned to provide tufts having a variety of topographies, including, e.g., angled, serrated, notched, scalloped, undulating, and combinations thereof. The spiral tuft can also be cut to exhibit a desired topography. For example, the spiral tuft can be cut at an angle, e.g., the brushing surface of the spiral tuft can extend at an angle of from about 20° to about 45°, more preferably from about 30° to about 40°, to the plane of the oral brush body.

Claims

C L A I M S

1. An oral brush comprising: a body; and a tuft comprising a first set of bristles secured to said body and arranged in a first spiral pattern; and a second set of bristles secured to said body and arranged in a second spiral pattern.

2. The oral brush of claim 1, wherein said second spiral pattern surrounds said first spiral pattern.

3. The oral brush of claim 2, wherein said second spiral pattern defines a central area and said first plurality of bristles is disposed entirely in said central area of said second spiral pattern.

4. The oral brush of claim 1 or 3, wherein said bristles of said first spiral pattern extend from said body to a first height, and said bristles of said second spiral pattern extend from said body to a second height, said first height being greater than said second height.

5. The oral brush of claim 1 or 3, wherein said bristles of said first spiral pattern extend from said body to a first height, and said bristles of said second spiral pattern extend from said body to a second height, said first height being less than said second height.

6. The oral brush of claim 1 or 3, wherein said bristles of said first spiral pattern have a first diameter; and said bristles of said second spiral pattern have a second diameter, said first diameter being greater than said second diameter.

7. The oral brush of claim 1 or 3, wherein said bristles of said first spiral pattern have a first diameter; and said bristles of said second spiral pattern have a second diameter, said first diameter being less than said second diameter.

8. The oral brush of claim 1, wherein the path of said first spiral pattern is substantially parallel to the path of said second spiral pattern.

9. The oral brush of claim 8, wherein said bristles of said first spiral pattern extend from said body to a first height, and said bristles of said second spiral pattern extend from said body to a second height, said first height being greater than said second height.

10. The oral brush of claim 8, wherein said bristles of said first spiral pattern extend from said body to a first height, and said bristles of said second spiral pattern extend from said body to a second height, said first height being less than said second height.

11. The oral brush of claim 8, wherein said bristles of said first spiral pattern have a first diameter; and said bristles of said second spiral pattern have a second diameter, said first diameter being greater than said second diameter.

12. The oral brush of claim 8, wherein said bristles of said first spiral pattern have a first diameter; and said bristles of said second spiral pattern have a second diameter, said first diameter being less than said second diameter.

13. The oral brush of claim 1, wherein said spiral tuft extends from said body to a first height, and said oral brush further comprises a plurality of second tufts extending from said body to a second height.

14. The oral brush of claim 8, wherein said height of said spiral tuft is greater than said height of said second tufts.

15. The oral brush of claim 8, wherein said height of said spiral tuft is less than said height of said second tufts.

16. The oral brush of claim 8, wherein said spiral tuft comprises a diameter and said second tufts comprise a diameter, said diameter of said spiral tuft being greater than said diameter of said second tufts.

17. The oral brush of claim 1, wherein said bristles extend at an angle toward the spiral center of said spiral tuft.

18. The oral brush of claim 1, wherein said bristles extend at an angle away from the spiral center of said spiral tuft.

19. The oral brush of claim 1, wherein said tuft comprises bristles comprising a first end secured to said body and a second end extending away from said body, said second ends of said bristles being dimensioned such that said tuft comprises a concave brushing surface.

20. The oral brush of claim 1, wherein said tuft comprises bristles comprising a first end secured to said body and a second end extending away from said body, said second ends of said bristles being dimensioned such that said tuft comprises a convex brushing surface.

21. The oral brush of claim 1, wherein said tuft comprises bristles comprising a first end secured to said body and a second end extending away from said body, said second ends of said bristles being dimensioned such that said tuft comprises a substantially flat brushing surface.

22. A method of using the oral brush of claim 1, said method comprising brushing the teeth of a mammal with said brush.

23. An oral brush comprising: a body; and a tuft secured to said body, said tuft comprising a first set of bristles arranged in a first spiral pattern defining a central open area; and a second set of bristles disposed within said central open area.

24. The oral brush of claim 23, wherein said bristles of said spiral pattern extend from said body to a first height, and said bristles of said second set of bristles extend from said body to a second height, said first height being greater than said second height.

25. The oral brush of claim 23, wherein said bristles of said spiral pattern extend from said body to a first height, and said second set of bristles extend from said body to a second height, said first height being less than said second height.

26. The oral brush of claim 23, wherein said bristles of said spiral pattern have a first diameter, and said bristles of said second set of bristles have a second diameter, said first diameter being greater than said second diameter.

27. The oral brush of claim 23, wherein said bristles of said spiral pattern have a first diameter, and said bristles of said second set of bristles have a second diameter, said first diameter being less than said second diameter.

28. The oral brush of claim 23, wherein said first tuft extends from said body to a first height, and said oral brush further comprises a set of second tufts extending from said body to a second height.

29. The oral brush of claim 28, wherein said height of said first tuft is greater than said height of said second tufts.

30. The oral brush of claim 28, wherein said height of said first tuft is less than said height of said second tufts.

31. The oral brush of claim 28, wherein said first tuft comprises a diameter and said second tufts comprise a diameter, said diameter of said first tuft being greater than said diameter of said second tufts.

32. The oral brush of claim 23, wherein said bristles of said spiral pattern extend at an angle toward the spiral center of said tuft.

33. The oral brush of claim 23, wherein said bristles of said spiral pattern extend at an angle away from the spiral center of said tuft.

34. The oral brush of claim 23, wherein said bristles comprise a first end secured to said body and a second end extending away from said body, said second ends of said bristles being dimensioned such that said tuft comprises a concave brushing surface.

35. The oral brush of claim 23, wherein said bristles comprise a first end secured to said body and a second end extending away from said body, said second ends of said bristles being dimensioned such that said tuft comprises a convex brushing surface.

36. The oral brush of claim 23, wherein said bristles comprise a first end secured to said body and a second end extending away from said body, said second ends of said bristles being dimensioned such that said tuft comprises a substantially flat brushing surface.

37. A method of using the oral brush of claim 23, said method comprising brushing the teeth of a mammal with said brush.

38. An oral brush comprising a body; and a tuft comprising a set of bristles extending from said body, said set of bristles being arranged in a spiral pattern such that the height of the bristles at the exterior of said pattern is greater than the height of the bristles at the interior of said pattern.

39. The oral brush of claim 38, wherein said spiral pattern defines a spiral path terminating at a center end point and an exterior end point, and the height of the bristles increases along the spiral path from said center end point to said exterior end point.

40. The oral brush of claim 38, wherein said spiral pattern defines a spiral path terminating at a center end point and an exterior end point, and the height of the individual bristles gradually increases along the spiral path from said center end point to said exterior end point.

41. An oral brush comprising a body; and a tuft comprising a set of bristles extending from said body, said set of bristles being aπanged in a spiral pattern such that the height of the bristles at the exterior of said pattern is less than the height of the bristles at the interior of said pattern.

42. The oral brush of claim 41, wherein said spiral pattern defines a spiral path terminating at a center end point and an exterior end point, and the height of the bristles decreases along the spiral path from said center end point to said exterior end point.

43. The oral brush of claim 41, wherein said spiral pattern defines a spiral path terminating at a center end point and an exterior end point, and the height of the individual bristles gradually decreases along the spiral path from said center end point to said exterior end point.

44. A tuft comprising: a set of bristles comprising individual bristles having a first end and a second end joined to the second end of an adjacent bristle, said second ends of said bristles terminating in a cup-like extension, said set of fused bristles being wound upon itself in the form of a spiral.

45. The tuft of claim 44, wherein said first ends of said bristles extend toward the center of said spiral.

46. The tuft of claim 44, wherein said first ends of said bristles extend toward the exterior of said spiral.

47. An oral brush comprising a body; and the tuft of claim 44 extending from said body.

48. A tuft comprising: a set of bristles comprising individual bristles having a first end and a second end fused to the second end of an adjacent bristle, said set of fused bristles being wound upon itself in the form of a spiral.

49. An oral brush comprising a body; and the tuft of claim 48 extending from said body.

50. A method of making a spiral tuft from a ribbon comprising bristles arranged adjacent one another and having a first end and a second end, a portion of said second ends being joined to the second end of an adjacent bristle, said method comprising: inserting a portion of said ribbon of bristles into a slit on a rod; and turning said rod such that said ribbon of bristles rolls upon itself to form a spiral tuft.

51. A method of manufacturing an oral brush comprising securing the tuft of claim 48 to a body.

52. A toothbrush comprising: a handle; a head extending from the handle; and a tuft of bristles, each bristle having a height in its longest dimension, one end of the tuft being secured to the head, the tuft having a width and a length which each extend in a direction different from the bristle height, a ratio of the weight to the length being about 0.25 or less.

53. The toothbrush of claim 52, wherein the bristles are substantially parallel to each other.

54. The toothbrush of claim 52, wherein the tuft is only a single layer of bristles wide.

55. The toothbrush of claim 52, wherein the tuft is more than one layer of bristles wide.

56. The toothbrush of claim 52, wherein the bristles are joined together at the one end of the tuft by one of (a) heat-fusion; (b) an adhesive, and (c) a synthetic and/or natural resin.

57. The toothbrush of claim 52, wherein one of the bristles has a characteristic that is different from that characteristic of another one of the bristles, the characteristic being selected from the group consisting of length, material, color, gray scale, surface characteristic and cross-sectional shape.

58. The toothbrush of claim 52, wherein the bristles are positioned in the tuft such that the ends of the bristles at the other end of the tuft are in a convex arrangement.

59. The toothbrush of claim 58, wherein the ends of the bristles at the other end of the tuft are in a convex arrangement when viewed along a direction that is parallel to the width dimension of the tuft.