WO2021253261A1

WO2021253261A1 - Toothbrush and anchor wire therefor

Info

Publication number: WO2021253261A1
Application number: PCT/CN2020/096485
Authority: WO
Inventors: Guoqiang Liu; Yanmei Ji; Bo Zhang
Original assignee: Colgate-Palmolive Company
Priority date: 2020-06-17
Filing date: 2020-06-17
Publication date: 2021-12-23
Also published as: EP4030963A4; CN115867170A; US20230210247A1; EP4030963A1

Abstract

A toothbrush (100) including a head portion (120) formed from bamboo. A plurality of tuft holes (130) are formed into the head portion (120) and a bristle tuft (151) is positioned within each of the tuft holes (130) and secured by an anchor wire (200). The anchor wire (200) may be formed from a metal alloy that includes nickel. The anchor wire (200) includes a plurality of first grooves (210) in its first surface (203) and a plurality of second grooves (220) in its second surface (204). The grooves (210, 220) may have sidewalls (212, 213, 222, 223) that are perpendicular to its floor (211, 221). A width (WG1, WG2) of the grooves (210, 220) may be equal to a spacing (D2, D5) between the grooves(210, 220) and greater than a thickness (T1) of the anchor wire (200).

Description

TOOTHBRUSH AND ANCHOR WIRE THEREFOR

BACKGROUND

As the deleterious effects of plastic on the environment become more of a concern, consumers are looking to purchase products that use less plastic. One industry that has products made predominately out of plastic is the toothbrush industry. One reason for this is that significant research and development has taken place to improve tuft retention in such plastic toothbrushes so that the bristles are not detaching from the toothbrush body during use. When looking to use a different base material for the toothbrush, bristle retention must be considered once again. Thus, a need exists for a non-plastic toothbrush having improved tuft retention, and for an anchor wire for securing bristles to a non-plastic toothbrush.

BRIEF SUMMARY

The present invention is directed to a toothbrush including a head portion formed from bamboo. A plurality of tuft holes are formed into the head portion and a bristle tuft is positioned within each of the tuft holes and secured by an anchor wire. The anchor wire may be formed from a metal alloy that includes nickel. The anchor wire includes a plurality of first grooves in its first surface and a plurality of second grooves in its second surface. The grooves may have sidewalls that are perpendicular to its floor. A width of the grooves may be equal to a spacing between the grooves and greater than a thickness of the anchor wire.

In one aspect, the invention may be a toothbrush comprising: a body comprising a handle portion and a head portion comprising a front surface, the body formed from bamboo; a plurality of tuft holes formed into the front surface of the head portion, each of the tuft holes comprising a floor that is recessed relative to the front surface of the head portion; a bristle tuft positioned within each of the tuft holes; an anchor wire positioned within each of the tuft holes to secure the bristle tufts to the head portion, each of the anchor wires formed from a metal alloy comprising nickel; each of the anchor wires comprising a bottom end adjacent to the floor of the tuft hole within which the anchor wire is positioned, a top end opposite the bottom end, a first anchor wire axis extending from the bottom end to the top end, and first and second surfaces extending from the bottom end to the top end; a plurality of first grooves formed into the first surface of each of the anchor wires and a plurality of second grooves formed into the second surface of each of the anchor wires, each of the first and second grooves extending along a groove axis that is perpendicular to the first anchor wire axis, each of the first grooves spaced apart from each adjacent one of the first grooves and each of the second grooves spaced apart from each adjacent one of the second grooves by a groove to groove spacing distance; and wherein each of the first and second grooves has a groove width measured in a direction parallel to the first anchor wire axis, the groove width being substantially equal to the groove to groove spacing distance.

In another aspect, the invention may be a toothbrush comprising: a body comprising a handle portion and a head portion comprising a front surface, the body formed from a cellulosic material; a plurality of tuft holes formed into the front surface of the head portion, each of the tuft holes comprising a floor that is recessed relative to the front surface of the head portion; a bristle tuft positioned within each of the tuft holes; an anchor wire positioned within each of the tuft holes to secure the bristle tufts to the head portion, each of the anchor wires formed from a metal alloy comprising nickel; each of the anchor wires comprising a bottom end adjacent to the floor of the tuft hole within which the anchor wire is positioned, a top end opposite the bottom end, a first anchor wire axis extending from the bottom end to the top end, and first and second surfaces extending from the bottom end to the top end; a plurality of first grooves formed into the first surface of each of the anchor wires and a plurality of second grooves formed into the second surface of each of the anchor wires, each of the first and second grooves extending along a groove axis that is perpendicular to the first anchor wire axis; and wherein each of the first grooves comprises a floor, a first sidewall extending from the floor to the first surface of the anchor wire, and a second sidewall extending from the floor to the first surface of the anchor wire, the first and second sidewalls being perpendicular to the floor, and wherein each of the second grooves comprises a floor, a first sidewall extending from the floor to the second surface of the anchor wire, and a second sidewall extending from the floor to the second surface of the anchor wire, the first and second sidewalls being perpendicular to the floor.

In yet another aspect, the invention may be a toothbrush comprising: a body comprising a handle portion and a head portion comprising a front surface, the body formed from bamboo; a plurality of tuft holes formed into the front surface of the head portion, each of the tuft holes comprising a floor that is recessed relative to the front surface of the head portion; a bristle tuft positioned within each of the tuft holes; an anchor wire positioned within each of the tuft holes to secure the bristle tufts to the head portion, each of the anchor wires formed from a metal alloy comprising nickel; each of the anchor wires comprising a bottom end adjacent to the floor of the tuft hole within which the anchor wire is positioned, a top end opposite the bottom end, a first anchor wire axis extending from the bottom end to the top end, first and second surfaces extending from the bottom end to the top end, and a thickness measured from the first surface to the second surface; a plurality of first grooves formed into the first surface of each of the anchor wires and a plurality of second grooves formed into the second surface of each of the anchor wires, each of the first and second grooves extending along a groove axis that is perpendicular to the first anchor wire axis; and wherein each of the first and second grooves has a groove width measured in a direction parallel to the first anchor wire axis, wherein the groove width is greater than the thickness of the anchor wire.

In a further aspect, the invention may be an anchor wire for securing bristle tufts to a toothbrush made from a cellulosic material, the anchor wire comprising: an anchor body formed from a metal alloy comprising nickel, copper, and zinc, the anchor body comprising a bottom end, a top end, a first surface, and a second surface, a first anchor axis extending from the bottom end to the top end; a plurality of first grooves formed into the first surface of the anchor body and extending along a first groove axis that is perpendicular to the first anchor axis, the plurality of first grooves positioned in a spaced apart manner such that adjacent ones of the first grooves are spaced apart by a first groove to groove spacing distance, each of the first grooves having a first groove width measured in a direction parallel to the first anchor axis; a plurality of second grooves formed into the second surface of the anchor body and extending along a second groove axis that is perpendicular to the first anchor axis, the plurality of second grooves positioned in a spaced apart manner such that adjacent ones of the second grooves are spaced apart by a second groove to groove spacing distance, each of the second grooves being in alignment with one of the first grooves, each of the second grooves having a second groove width measured in a direction parallel to the first anchor axis; each of the first grooves comprising a floor, a first sidewall extending from the floor to the first surface of the anchor body, and a second sidewall extending from the floor to the first surface of the anchor body, the first and second sidewalls being perpendicular to the floor; each of the second grooves comprising a floor, a first sidewall extending from the floor to the second surface of the anchor body, and a second sidewall extending from the floor to the second surface of the anchor body, the first and second sidewalls being perpendicular to the floor; and wherein the first and second groove widths and the first and second groove to groove spacing distances are the same.

Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:

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

FIG. 2 is a close-up view of area II of FIG. 1 illustrating a head portion of the toothbrush;

FIG. 3 is a side view of the head portion of the toothbrush of FIG. 1;

FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 2;

FIG. 5 is a perspective view of an anchor wire of the toothbrush of FIG. 1 used to secure bristle tufts to the head portion;

FIG. 6 is a top plan view of the anchor wire of FIG. 5;

FIG. 7 is a front view of the head portion of the toothbrush of FIG. 1 with bristle tufts omitted to show anchor wires positioned within tuft holes in the head portion;

FIG. 7A is a partial perspective view illustrating the orientation of the anchor wire as it is inserted into a tuft hole in the head portion of the toothbrush of FIG. 1;

FIG. 8 is a to plan view of an anchor wire in accordance with the prior art; and

FIG. 9 is a graphical representation comparing tuft retention in the toothbrush of FIG. 1 using the anchor wire of FIGS. 6 and 7 and the anchor wire of FIG. 8.

DETAILED DESCRIPTION

The following description of the preferred embodiment (s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.

The description of illustrative embodiments according to principles of the present invention is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description. In the description of embodiments of the invention disclosed herein, any reference to direction or orientation is merely intended for convenience of description and is not intended in any way to limit the scope of the present invention. Relative terms such as “lower, ” “upper, ” “horizontal, ” “vertical, ” “above, ” “below, ” “up, ” “down, ” “top” and “bottom” as well as derivatives thereof (e.g., “horizontally, ” “downwardly, ” “upwardly, ” etc. ) should be construed to refer to the orientation as then described or as shown in the drawing under discussion. These relative terms are for convenience of description only and do not require that the apparatus be constructed or operated in a particular orientation unless explicitly indicated as such. Terms such as “attached, ” “affixed, ” “connected, ” “coupled, ” “interconnected, ” and similar refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. Moreover, the features and benefits of the invention are illustrated by reference to the exemplified embodiments. Accordingly, the invention expressly should not be limited to such exemplary embodiments illustrating some possible non-limiting combination of features that may exist alone or in other combinations of features; the scope of the invention being defined by the claims appended hereto.

Referring first to FIG. 1, a toothbrush 100 is illustrated in accordance with an embodiment of the present invention. The toothbrush 100 comprises a body 101 having a handle portion 110 and a head portion 120. The body 101 is a single, unitary construction such that the handle portion 110 and the head portion 120 are part of the same monolithic component. The body 101 may be formed from a cellulosic material, which as used herein includes wood and plant-based materials including bamboo. The term cellulosic material as used herein specifically excludes plastic such as polypropylene, polyethylene, or the like. Thus, the body 101 in some embodiments is formed from bamboo and in other embodiments is formed from wood, but in accordance with the exemplified embodiment the body 101 is not formed from nor does it comprise any amount of plastic. As used herein, the term cellulosic material may comprise wood materials and parts thereof and bamboo materials and parts thereof.

The body 101 extends from a proximal end 102 (which forms a proximal end of the handle portion 110) to a distal end 103 (which forms a distal end of the head portion 120) along a longitudinal axis A-A. As noted above, the handle portion 110 and the head portion 120 may be formed as an integral unitary structure, although in other embodiments it may be possible for the head portion 120 to be detachable from the handle portion 110 so that the head portion 120 can be replaced when the bristles thereon become worn. Thus, in the exemplified embodiment a distal end 104 of the handle portion 110 is coupled directly to a proximal end 105 of the head portion 120 as a one-piece unit.

The handle portion 110 is the portion of the body 101 that is gripped by a user during use thereof. Thus, the handle portion 110 preferably has a length and width that is selected for user comfort so that a user can clasp his/her hand around the handle portion 110 to use the toothbrush 100 for oral cavity treatment such as toothbrushing. The handle portion 110 is elongated and may have various contours to enhance user comfort. In the exemplified embodiment, the side surfaces of the handle portion 110 may be wavy to allow the handle portion 110 to sit more comfortably within a user’s palm and fingers. The handle portion 110 may have flat front and rear surfaces and/or may include bumps, ridges, or protrusions to enhance grip. The handle portion 110 may be partially or fully encased or covered with a gripping material, such as a thermoplastic elastomer, to further increase the gripability thereof. Thus, various modifications and enhancements to the handle portion 110 are possible within the scope of the invention described herein and the invention is not intended to be limited by the structure or shape of the handle portion 110 shown in the drawings in all embodiments. In some embodiments, the cellulosic material (e.g., wood, bamboo) that forms the body 101 may be coated with beeswax to prevent mold growth and prolong the life of the body 101 as it is normally used under wet conditions.

Referring to FIGS. 1-4, the head portion 120 will be described. The head portion 120 extends from the proximal end 105 where it is connected to the handle portion 110 to the distal end 103 of the body 101 which is also the distal end of the head portion 120. The head portion 120 extends along the longitudinal axis A-A of the body 101. The head portion 120 comprises a front surface 123, a rear surface 124 opposite the first surface 123, and a peripheral surface 125 extending between the front and

rear surfaces

123, 124. The region where the peripheral surface 125 intersects the front surface 123 may be referred to herein as a perimeter 128 of the head portion 120.

A plurality of tuft holes 130 are formed into the front surface 123 of the head portion 120, the details of which are best shown in FIG. 4. Each of the tuft holes 130 is a hole formed into the front surface 123 of the head portion 120 having a height that is less than a thickness of the head portion 120 measured between the front and

rear surfaces

123, 124 of the head portion 120. Thus, each of the tuft holes 130 comprises a floor 131 that is recessed relative to the front surface 123 of the head portion 120 and a sidewall 132 that extends from the floor 131 to the front surface 123 of the head portion 120. The tuft holes 130 do not extend entirely through the head portion 120 to the rear surface 124. Thus, while the tuft holes 130 have openings in the front surface 123 of the head portion 120, there are no openings to the tuft holes 130 in the rear surface 124 of the head portion. The tuft holes 130 have round cross-sectional areas in the exemplified embodiment, but they could take on other shapes in other embodiments. The tuft holes 130 may have a diameter of between 1.2 and 2.0mm, more specifically 1.4 and 1.8 mm, still more specifically between 1.5 and 1.7 mm, and even more specifically approximately 1.6 mm. The tuft holes 130 may all have the same diameter or there may be tuft holes 130 with different diameters formed into the head portion 120. The tuft holes 130 are arranged on the front surface 123 of the head portion 120 in a spaced apart manner, each configured to receive a bristle tuft or other style tooth cleaning element as described below. The particular location, arrangement, pattern, spacing, diameter, or the like of the tuft holes 130 is not to be limiting of the invention in all embodiments.

In the exemplified embodiment, a plurality of bristle tufts 151 are anchored to the head portion 120 of the body 101 so that each of the bristle tufts 151 extends from the front surface 123 of the head portion 120. Specifically, in the exemplified embodiment one of the bristle tufts 151 is positioned within each of the tuft holes 130. Only a few of the bristle tufts 151 are labeled in FIGS. 1-3 in order to prevent clutter. Each of the plurality of bristle tufts 151 is located within one of the tuft holes 130 in the head portion 120 and secured thereto by an anchor wire 200. The bristle tufts 151 collectively define a bristle field 150.

Each of the bristle tufts 151 comprises a plurality of bristles that are clumped together to form the bristle tuft 151, which is then inserted into a singular tuft hole formed into the head portion 120. The bristles within each of the bristle tufts 151 may be, for example without limitation, filament bristles, fiber bristles, nylon bristles, polybutylene terephthalate (PBT) bristles, spiral bristles, core-sheath bristles, tapered bristles, end-rounded bristles, or the like. Combinations of these different bristle types may be positioned in the same bristle tuft 151 or each bristle tuft 151 may contain only one bristle type. The bristles may have varying diameters including 7 mm, 8 mm, and 9 mm. Some of the bristles and/or bristle tufts 151 may be infused with charcoal, bamboo salt, or other natural ingredients as may be desired to impart a benefit into an oral cavity of a user during use of the toothbrush 100 for oral hygiene activities.

In the exemplified embodiment, to secure the bristle tufts 151 to the head portion 120, the bristle tufts 151 are folded into a U shape and then driven into the tuft hole 130 with the anchor wire 200. Thus, the anchor wire 200 rests atop a bight portion 155 of the U shape of the bristle tufts 151 and sandwiches the bight portion 155 between the anchor wire 200 and the floor 131 of the tuft hole 130. Thus, the anchor wire 200 is not driven so far into the tuft hole 130 so as to make contact with the floor 131, but rather the anchor wire 200 remains spaced from the floor 131 of the tuft hole 130 so that the bristles of the bristle tuft 151 can pass underneath the anchor wire 200 between the anchor wire 200 and the floor 131 of the tuft hole 130. The anchor wire 200 may become partially embedded within the material of the head portion 120 (i.e., within the sidewall 132 of the tuft hole 130) to secure the anchor wire 200 in place within the tuft hole 130. For example, in some embodiments the tuft hole 130 has a diameter of 1.6mm and the anchor wire 200 has a width of 2.2mm, such that 0.3mm on each end of the anchor wire 200 is embedded within the sidewall 132 of the tuft hole 130 within which it is positioned. This results in the anchor wire 200 being securely coupled to the head portion 120 of the toothbrush 100. It should be noted that such embedment of the anchor wire 200 in the head portion 200 is not required in all embodiments and it may be possible to secure the anchor wire 200 to the head portion 120 via a friction fit between the edges of the anchor wire 200 and the sidewall 132 of the tuft hole 130, using adhesives, or other technical means. As the anchor wire 200 is coupled to the head portion 120 of the toothbrush 100, the anchor wire 200 holds the bristle tuft 151 in place within the tuft hole 130.

One important consideration in toothbrush manufacture is tuft retention, which is a measure of the force required to detach the bristles of the bristle tuft 151 from the head portion 120 of the toothbrush 100 (i.e., the holding force of filament tufts in the head portion 120 of the toothbrush 100) . Specifically, if the toothbrush 100 has poor tuft retention, then the bristles of the bristle tufts 151 will more readily become detached from the head portion 120 of the toothbrush 100 during use whereas if the toothbrush 100 has good tuft retention the bristles of the bristle tufts 151 are less likely to become detached from the head portion 120 of the toothbrush 100 during use. As will be discussed in greater detail below, the anchor wire 200 of the invention described herein has been specifically designed to increase tuft retention in the toothbrush 100 which is formed from a cellulosic material such as wood or bamboo.

In the exemplified embodiment, the bristle tufts 151 comprising filament bristles are the only tooth cleaning elements coupled to and extending from the head portion 120. Of course, the invention is not to be so limited in all embodiments and in some alternative embodiments there may also be lamella or rubber cleaning elements including rubber bristles, elastomeric protrusions, flexible polymer protrusions, or the like extending from the head. Thus, cleaning elements for cleaning, polishing, or wiping the teeth and/or soft oral tissue may be formed from other materials and provided on the head portion 120 alongside of the bristle tufts 151.

As best seen in FIG. 3, in the exemplified embodiment the bristle field 150 formed by the plurality of bristle tufts 151 has a flat trim profile. Specifically, each of the bristle tufts 151 has the same height measured from the front surface 123 of the head portion 120 to a distal end 152 of the bristle tuft 151. As a result, the distal ends 152 of the bristle tufts 151 collectively lie on a common plane that is parallel to the front surface 123 of the head portion 120. However, the invention is not to be so limited in all embodiments and in some other embodiments the bristle tufts 151 may have varying heights to create a wavy or other trim profile that is not flat and planar as shown in the exemplified embodiment. The arrangement, pattern, location, position, orientation, angle, and other features related to the placement of the tuft holes 130 and the bristle tufts 151 are not to be limiting of the present invention in all embodiments and may be modified to suit a particular purpose.

Referring to FIGS. 5 and 6, the anchor wire 200 that may be used to secure the bristle tufts 151 within the tuft holes 130 of the toothbrush 100 will be described in greater detail. The anchor wires 200 may comprise an anchor body 250. One of the anchor wires 200 is inserted within each of the tuft holes 130 that contains a bristle tuft 150 in order to secure the bristle tuft 150 within the tuft hole 130 with sufficient retention so that limited, if any, bristles of the bristle tuft 150 are removed during normal use of the toothbrush 100. The use of the anchor wires 200 for securing the bristle tufts 151 to the head portion 120 of the toothbrush 100 is commonly referred to as a staple technique. Basically, the bristle tufts 151 are bent into a U shape around the anchor wire 200 to form a bristle-anchor wire subassembly. The bristle-anchor wire subassembly is then placed into the tuft holes 130. The engagement between the anchor wire 200 and the head portion 120 of the toothbrush 100 (via embedment of the anchor wire 200 as described above, friction, or any other technical means) ensures that the bristle tufts 151 are retained within the tuft holes 130. The ability of the anchor wires 200 to remain in place assists with bristle retention by preventing bristles from being detached from the head portion 120 during normal use of the toothbrush 100.

In accordance with the invention set forth herein, the anchor wires 200 may be formed from a metal alloy that comprises nickel. In some embodiments, the anchor wire 200 may be formed from a metal alloy comprising nickel, copper, and zinc. In other embodiments, the metal alloy may comprise nickel, copper, lead, and zinc. In one exemplary embodiment, the metal alloy may comprise 8-15wt%nickel and 50-70wt%copper. In another more particular embodiment, the metal alloy may comprise 11-12wt%nickel and 61-62wt%copper. In some embodiments, the remainder of the metal alloy is formed from zinc. In other embodiments there may be a small amount of lead, such as between 0.1wt%and 2wt%, or approximately 0.3wt%lead with the remainder formed by zinc. In other embodiments, the metal alloy may comprise copper and nickel in the noted weight percentages and other metal materials. However, in accordance with embodiments of the invention set forth herein, the metal alloy used to form the anchor wires 200 of the toothbrush 100 comprises at least 10wt%nickel.

Furthermore, in certain embodiments the metal alloy comprises nickel and specifically does not include any brass. Nickel is a harder metal than brass. It has been found through experimentation by the inventors of the invention set forth herein that tuft retention is improved in a toothbrush formed from a cellulosic material such as bamboo when the anchor wire 200 described herein is formed from a metal alloy comprising nickel and excluding brass (as compared to the metal alloy comprising brass) . The graph shown in FIG. 9 and described below further illustrates the increased tuft retention with the anchor wire 200 formed from a metal alloy that comprises nickel.

In the exemplified embodiment, the anchor wire 200 is a double sided grooved anchor having grooves on opposing major surfaces, with the grooves being square or rectangular shaped. The anchor wire 200 has a generally rectangular shape, although the shape and dimensions of the tuft hole within which the anchor wire 200 is to be positioned may dictate varying the shape of the anchor wire 200 as should be appreciated. The anchor wire 200 comprises a bottom end 201, a top end 202, a first surface 203 extending from the bottom end 201 to the top end 202, a second surface 204 extending from the bottom end 201 to the top end 202, a first side end 205 extending between the bottom and top ends 201, 202 and between the first and

second surfaces

203, 204, and a second side end 206 extending between the bottom and top ends 201, 202 and between the first and

second surfaces

203, 204. The first and

second surfaces

203, 204 may be considered the major surfaces of the anchor wire 200 because they are the surfaces having the largest surface area. The anchor wire 200 extends from the bottom end 201 to the top end 202 along a first anchor wire axis B-B and from the first side end 205 to the second side end 206 along a second anchor wire axis C-C that is perpendicular to the first anchor wire axis B-B.

In the exemplified embodiment, the top and bottom ends 201, 202 are chamfered. That is, the top end 201 comprises an end wall 281, a first oblique wall 282 extending from the end wall 281 to the first surface 203, and a second oblique wall 283 extending from the end wall 281 to the second surface 204. Each of the first and second

oblique walls

282, 283 intersects the end wall 281 at an oblique angle, which in the exemplified embodiment is an obtuse angle. Similarly, the bottom end 202 comprises an end wall 292, a first oblique wall 292 extending from the end wall 281 to the first surface 203, and a second oblique wall 293 extending from the end wall 291 to the second surface 204. Each of the first and

second walls

292, 293 intersects the end wall 291 at an oblique angle, which in the exemplified embodiment is an obtuse angle. such that they each include an end wall and two angled walls extending from the end wall to the first and

second surfaces

203, 204.

There are multiple benefits to the chamfering of the top end 202, and more particularly the bottom end 201. First, this reduces the likelihood that the anchor wire 200 will break the bristles of the bristles tufts 151 as the subassembly is being inserted into the tuft holes 130. Specifically, because the bristles are able to wrap around the first and second

oblique walls

292, 293, the corner that contacts the bristles (i.e., the corner between the first and second

oblique walls

292, 293 and the end wall 291) is not as sharp as it would be if the

oblique walls

292, 293 were omitted and the first and

second surfaces

203, 204 instead connected directly to the end wall 291. Furthermore, as noted herein, the anchor wire 200 is intended for use in a toothbrush that is made from a cellulosic material such as wood or bamboo. It is known that such cellulosic materials may split when a structure is driven into it (for example, when a nail is hammered into wood it can split the wood, but flattening the sharp point of the nail helps to reduces such splitting) . The same result is achieved here, which may ensure that the insertion of the anchor wires 200 into the tuft holes 130 does not cause the cellulosic material of the head portion 120 of the toothbrush 100 to split or otherwise become damaged.

Referring briefly to FIGS. 4 and 7A, the anchor wire 200 is positioned in the tuft hole 130 so that the bottom end 201 of the anchor wire 200 is adjacent to the floor 131 of the tuft hole 130, although the bottom end 201 of the anchor wire 200 is spaced apart from the floor 131 of the tuft hole 130 so that the bristles can pass through the space between the anchor wire 200 and the floor 131. The top end 202 of the anchor wire 200 is recessed relative to the front surface 123 of the head portion 120. The first and second side ends 205, 206 of the anchor wire 200 are either abutted against or embedded within the sidewalls 132 of the tuft holes 130 (best shown in FIG. 7 described below) to couple the anchor wire 200 to the head portion 120 of the toothbrush 100.

Referring again to FIGS. 5 and 6, the anchor wire 200 has a length L1 measured from the bottom end 201 to the top end 202 and a width W1 measured from the first side end 205 to the second side end 206. In the exemplified embodiment, the width W1 is greater than the length L1. In some embodiments, the width W1 may be between 2.0mm and 2.4mm, and more specifically approximately 2.2mm. Furthermore, the length L1 may be between 1.8mm and 2.2mm, and more specifically approximately 2.0mm. The anchor wire 200 also has a thickness T1 measured from the first surface 203 to the second surface 204. In the exemplified embodiment, the thickness T1 is between 0.26mm and 0.30mm, and more specifically approximately 0.28mm. The term “approximately” as used in this sense and throughout this specification includes a tolerance (plus or minus) of 5%. In one particular embodiment, the length L1 may be exactly 2.2mm, the width W1 may be exactly 2.0mm, and the thickness T1 may be exactly 0.28mm.

The anchor wire 200 comprises a plurality of first grooves 210 formed into the first surface 203 and a plurality of second grooves 220 formed into the second surface 204. Each of the first grooves 210 extends along a groove axis D-D (only one of which is labeled in the drawings) which is perpendicular to the first anchor wire axis B-B and parallel to the second anchor wire axis C-C. Stated another way, each of the first and

second grooves

210, 220 extends from the first side end 205 of the anchor wire 200 to the second side end 206 of the anchor wire 200. Thus, each of the plurality of first grooves 210 and each of the plurality of second grooves 220 extend an entirety of the width W1 of the anchor wire 200 from the first side end 205 to the second side end 206. Each of the first and

second grooves

210, 220 has a length measured in a direction of the groove axis D-D that is identical to the width W1 of the anchor wire 200.

Furthermore, because the anchor wire 200 is positioned within the tuft holes 130 with the bottom end 201 of the anchor wire 200 adjacent to the floor 131 of the tuft hole 130, the first and

second grooves

210, 220 extend horizontally in a direction that is parallel to the plane of the head portion 120 and perpendicular to the axis of the tuft hole 130. This creates additional friction between the anchor wire 200 and the sidewalls 132 of the tuft hole 130. Each of the second grooves 220 is aligned with one of the first grooves 210, as best shown in FIG. 6. Thus, moving in a direction from the bottom end 201 of the anchor wire 200 to the top end 202 of the anchor wire 200, wherever there is a first groove 210 in the first surface 203 there is also a second groove 220 in the second surface 204. Stated another way, any axis that is perpendicular to both of the first and

second surfaces

203, 204 of the anchor wire 200 which intersects one of the first grooves 210 will also intersect one of the second grooves 220, and vice versa. Any axis that is perpendicular to both of the first and

second surfaces

203, 204 of the anchor wire 200 which does not intersect one of the first grooves 210 will also not intersect one of the second grooves 220.

Each of the first grooves 210 comprises a floor 211, a first sidewall 212 extending from the floor 211 to the first surface 203, and a second sidewall 213 extending from the floor 211 to the first surface 203. The floor 211 is recessed relative to the first surface 203 of the anchor wire 200. The first and

second sidewalls

212, 213 are perpendicular to the floor 211, which gives the first grooves 210 their square or rectangular shape. Thus, a 90° angle is formed at the intersection of the floor 211 and the first and

second sidewalls

212, 213 of the first grooves 210, although the comers where the first and

second sidewalls

212, 213 intersect the floor 211 could be somewhat rounded due to the manufacturing process as shown in FIG. 6. Regardless, the first and

second sidewalls

212, 213 still extend perpendicularly relative to the floor 211.

The first grooves 210 have a first groove depth D1 measured from the floor 211 of the first groove 210 to the first surface 203 of the anchor wire 200. In the exemplified embodiment, the first groove depth D1 is approximately 0.05mm (the term approximately including a tolerance of plus/minus 5%) .

The first grooves 210 have a first groove width WG1 measured from the first sidewall 212 to the second sidewall 213. Thus, the first groove width WG1 is measured in a direction parallel to the first anchor wire axis B-B and perpendicular to the groove axis D-D and to the second anchor wire axis C-C. In the exemplified embodiment, each of the first grooves 210 has the same first groove width WG1. In the exemplified embodiment, the first groove width WG1 may be between 0.28mm and 0.32mm, and more specifically approximately 0.30mm. As noted above, the term approximately used herein includes a tolerance of plus or minus 5%from the provided value or dimension. In some embodiments the first groove width WG1 is greater than the thickness T1 of the anchor wire 200.

The first grooves 210 are spaced apart from one another by a first groove to groove spacing distance D2. The first groove to groove spacing distance D2 is the distance between one of the first grooves 210 and an immediately adjacent one of the first grooves 210 measured in a direction of the first anchor wire axis B-B. The first groove to groove spacing distance D2 only includes space between adjacent ones of the first grooves 210 and does not include any portion of the width of the first grooves 210. In the exemplified embodiment, the first groove to groove spacing distance D2 may be between 0.28mm and 0.32mm, and more specifically approximately 0.30mm (with approximately including a tolerance of plus/minus 5%) . Thus, in the exemplified embodiment the first groove width WG1 and the first groove to groove spacing distance D2 are the same, or substantially equal (with the term substantially allowing for a tolerance such that one of the first groove width WG1 and the first groove to groove spacing distance D2 may be up to 5%greater than the other) .

Furthermore, the plurality of first grooves 210 comprises end-most grooves that are positioned closest to the bottom and top ends 201, 202 of the anchor wire 200. The end-most groove closest to the bottom end 201 of the anchor wire 200 is spaced apart from the bottom end 201 of the anchor wire 200 by a first groove to end spacing distance D3. Although not shown in the drawings, the end-most groove closest to the top end 202 of the anchor wire 200 is also spaced apart from the top end 202 of the anchor wire 200 by the first groove to end spacing distance D3. In the exemplified embodiment, the first groove to end spacing distance D3 is between 0.22mm and 0.28mm, and more specifically approximately 0.25mm (approximately including a tolerance of plus/minus 5%) .

In one specific embodiment of the invention, the anchor wire 200 may have the following dimensions: the first groove width WG1 of approximately 0.3mm, the first groove to groove spacing distance D2 of approximately 0.3mm, the thickness T1 of approximately 0.28mm, the first groove depth D1 of approximately 0.05mm, and the first groove to end spacing distance D3 of approximately 0.25mm.

Thus, in certain embodiments, the first groove width WG1 and the first groove to groove spacing distance D2 are the same. Furthermore, the first groove width WG1 and the first groove to groove spacing distance D2 are greater than the first groove to end spacing distance D3. A ratio of the first groove width WG1 to the first groove to end spacing distance D3 may be between 1.1: 1 and 1.3: 1. Moreover, in some embodiments a ratio of the first groove width WG1 to the first groove depth D1 may be between 5: 1 and 8: 1, and more specifically 5.5: 1 and 6.5: 1. In some embodiments, a ratio of the thickness T1 of the anchor wire 200 to the first groove depth D1 may be greater than 4: 1 and less than 6: 1.

The second grooves 220 have an identical structure, shape, size, and the like as the first grooves 210. Each of the second grooves 220 comprises a floor 221, a first sidewall 222 extending from the floor 221 to the second surface 204, and a second sidewall 223 extending from the floor 221 to the second surface 204. The floor 221 is recessed relative to the second surface 204 of the anchor wire 200. The first and

second sidewalls

222, 223 are perpendicular to the floor 221. Thus, a 90° angle is formed at the intersection of the floor 221 and the first and

second sidewalls

222, 223 of the second grooves 220, although the corners where the first and

second sidewalls

222, 223 intersect the floor 221 could be somewhat rounded due to the manufacturing process as shown in FIG. 6. Regardless, the first and

second sidewalls

222, 223 still extend perpendicularly relative to the floor 221.

The second grooves 220 have a second groove depth D4 measured from the floor 221 of the second groove 220 to the second surface 204 of the anchor wire 200. In the exemplified embodiment, the second groove depth D4 is approximately 0.05mm (approximately including a tolerance of plus/minus 5%) . The second groove depth D4 of the second grooves 220 may be the same as the first groove depth D1 of the first grooves 210.

The second grooves 220 have a second groove width WG2 measured from the first sidewall 222 to the second sidewall 223 in a direction of the first anchor axis B-B and perpendicular to the groove axis D-D and to the second anchor axis C-C. Each of the second grooves 220 has the same second groove width WG2. In the exemplified embodiment, the second groove width WG2 may be between 0.28mm and 0.32mm, and more specifically approximately 0.30mm. As noted above, the term approximately used herein includes a tolerance of plus or minus 5%from the provided value or dimension. In some embodiments the second groove width WG2 may be identical to the first groove width WG1 and may be greater than the thickness T1.

The second grooves 220 are spaced apart from one another by a second groove to groove spacing distance D5. The second groove to groove spacing distance D5 is the distance between one of the second grooves 220 and an immediately adjacent one of the second grooves 220 in a direction of the first anchor axis B-B. The second groove to groove spacing distance D5 only includes space between adjacent ones of the second grooves 220 and does not include any portion of the width of the second grooves 220. In the exemplified embodiment, the second groove to groove spacing distance D5 may be between 0.28mm and 0.32mm, and more specifically approximately 0.30mm (with approximately including a tolerance of plus/minus 5%) . Thus, in the exemplified embodiment the second groove width WG2 and the second groove to groove spacing distance D5 are the same or substantially equal (with the term substantially allowing for a tolerance such that one of the second groove width WG2 and the second groove to groove spacing distance D5 may be up to 5%greater than the other) . The second groove width WG2 may also be the same as the first groove width WG1 and the second groove to groove spacing distance D5 may be the same as the first groove to groove spacing distance D2.

Furthermore, the plurality of second grooves 220 comprises end-most grooves that are positioned closest to the bottom and top ends 201, 202 of the anchor wire 200. The end-most one of the second grooves closest to the bottom end 201 of the anchor wire 200 is spaced apart from the bottom end 201 of the anchor wire 200 by a second groove to end spacing distance D6. Although not shown in the drawings, the end-most one of the second grooves closest to the top end 202 of the anchor wire 200 is also spaced apart from the top end 202 of the anchor wire 200 by the second groove to end spacing distance D6. In the exemplified embodiment, the second groove to end spacing distance D6 is between 0.22mm and 0.28mm, and more specifically approximately 0.25mm (approximately including a tolerance of plus/minus 5%) . Thus, the dimensions of the second grooves 220 and the spacing therebetween and relative to the bottom and top ends 201, 202 are identical to that which was provided above for the first grooves 210. In the exemplified embodiment, the second groove to end spacing distance D6 is the same as the first groove to end spacing distance D3.

In one specific embodiment of the invention, the anchor wire 200 may have the following dimensions: the second groove width WG2 of approximately 0.3mm, the second groove to groove spacing distance D5 of approximately 0.3mm, the thickness T1 of approximately 0.28mm, the second groove depth D4 of approximately 0.05mm, and the second groove to end spacing distance D6 of approximately 0.25mm.

Thus, in certain embodiments, the second groove width WG2 and the second groove to groove spacing distance D5 are the same. Furthermore, the second groove width WG2 and the second groove to groove spacing distance D5 are greater than the second groove to end spacing distance D6. A ratio of the second groove width WG2 to the second groove to end spacing distance D6 may be between 1.1: 1 and 1.3: 1. Moreover, in some embodiments a ratio of the second groove width WG2 to the second groove depth D2 may be between 5: 1 and 8: 1, and more specifically 5.5: 1 and 6.5: 1. In some embodiments, a ratio of the thickness T1 of the anchor wire 200 to the second groove depth D4 may be greater than 4: 1 and less than 6: 1.

In certain embodiments, the anchor wire 200 may have a second thickness T2 measured from the floor 211 of one of the first grooves 210 to the floor 221 of the one of the second grooves 220 that is aligned with the first groove 210. A ratio of the second thickness T2 to a sum of the first and second groove depths (T2: (D1+D4) ) may be in a range of 1.5: 1 and 2.5: 1, and more specifically between 1.5: 1 and 2.0: 1, and still more specifically approximately 1.8: 1. Furthermore, a ratio of the thickness T1 of the anchor wire 200 to the second thickness T2 may be between 1.3: 1 and 1.8: 1, and more specifically between 1.5: 1 and 1.6: 1. Finally, a ratio of the first groove width WG1 or the second groove width WG2 to the thickness T2 may be in a range of 1.5: 1 and 1.8: 1, and more specifically between 1.6: 1 and 1.7: 1.

Referring to FIG. 7, the head portion 120 of the toothbrush 100 is illustrated with the bristle tufts omitted. Furthermore, in FIG. 7 one of the anchor wires 200 is illustrated positioned within each of the tuft holes 130. In the exemplified embodiment, each of the anchor wires 200 is positioned within one of the tuft holes 130 in the same orientation. Thus, the second anchor axes C-C of each of the plurality of anchor wires 200 are parallel to one another when the anchor wires 200 are disposed within the tuft holes 130. Furthermore, although not shown, the groove axes D-D are parallel to the second anchor axes C-C and thus are oriented as shown in FIG. 7 as well. Moreover, each of the anchor wires 200 is positioned within one of the tuft holes 130 so that the second anchor axes C-C and the groove axes D-D are oblique to the longitudinal axis A- A of the toothbrush 100 and the head portion 120 thereof. More specifically, the second anchor axes C-C and the groove axes D-D of the anchor wires 200 form an oblique angle θ1 with the longitudinal axis A-A of the head portion 120 of at least 10 degrees. In other embodiments, the oblique angle θ1 is at least 15 degrees. In some embodiments, the oblique angle θ1 is between 10 degrees and 20 degrees, and more specifically between 12 degrees and 18 degrees, and more specifically between 14 degrees and 16 degrees, and still more specifically approximately 15 degrees.

FIG. 8 illustrates an anchor wire 300 of the prior art that is previously known to have been used on toothbrushes formed from cellulosic material such as bamboo. The anchor wire 300 of FIG. 8 is formed from brass or a metal alloy comprising brass and devoid of nickel. The anchor wire 300 is a double grooved anchor wire in that it has grooves on both faces thereof similar to the anchor wire 200. However, the sidewalls of the grooves of the anchor wire 300 are not perpendicular to the floor of the grooves of the anchor wire 300. Thus, the grooves have a trapezoidal shape instead of a square/rectangular shape. Without intending to be bound by theory, it is believed that the combination of forming the anchor wire 200 from a metal alloy comprising nickel and such that the first and

second grooves

210, 220 have walls that are perpendicular to its floor has resulted in the toothbrush 100 having an improved tuft retention due to the stronger nickel material and an increased friction between the anchor wire 200 and the sidewall 132 of the tuft hole 130.

Referring to FIG. 9, a graph illustrating the tuft retention for the toothbrush 100 formed from bamboo using the anchor wire 300 of FIG. 8 and using the anchor wire 200 of FIGS. 5 and 6 is provided. As can be seen, the average tuft retention with the anchor wire 200 is 41.6 N whereas the average tuft retention with the anchor wire 300 is 30.4. This illustrates that there is a significant improvement in tuft retention when the anchor wire 300 is used in the toothbrush 100 to hold the bristle tufts 150 in the tuft holes 130 as compared to when the anchor wire 200 of the prior art is used in the toothbrush 100 to hold the bristle tufts 150 in the tuft holes 130.

As used throughout, ranges are used as shorthand for describing each and every value that is within the range. Any value within the range can be selected as the terminus of the range. In addition, all references cited herein are hereby incorporated by reference in their entireties. In the event of a conflict in a definition in the present disclosure and that of a cited reference, the present disclosure controls.

While the invention has been described with respect to specific examples including presently preferred modes of carrying out the invention, those skilled in the art will appreciate that there are numerous variations and permutations of the above described systems and techniques. It is to be understood that other embodiments may be utilized and structural and functional modifications may be made without departing from the scope of the present invention. Thus, the spirit and scope of the invention should be construed broadly as set forth in the appended claims.

Claims

A toothbrush comprising:

a body comprising a handle portion and a head portion comprising a front surface, the body formed from bamboo;

a plurality of tuft holes formed into the front surface of the head portion, each of the tuft holes comprising a floor that is recessed relative to the front surface of the head portion;

a bristle tuft positioned within each of the tuft holes;

an anchor wire positioned within each of the tuft holes to secure the bristle tufts to the head portion, each of the anchor wires formed from a metal alloy comprising nickel;

each of the anchor wires comprising a bottom end adjacent to the floor of the tuft hole within which the anchor wire is positioned, a top end opposite the bottom end, a first anchor wire axis extending from the bottom end to the top end, and first and second surfaces extending from the bottom end to the top end;

a plurality of first grooves formed into the first surface of each of the anchor wires and a plurality of second grooves formed into the second surface of each of the anchor wires, each of the first and second grooves extending along a groove axis that is perpendicular to the first anchor wire axis, each of the first grooves spaced apart from each adjacent one of the first grooves and each of the second grooves spaced apart from each adjacent one of the second grooves by a groove to groove spacing distance; and

wherein each of the first and second grooves has a groove width measured in a direction parallel to the first anchor wire axis, the groove width being substantially equal to the groove to groove spacing distance.
The toothbrush according to claim 1 wherein each of the first grooves comprises a floor, a first sidewall extending from the floor to the first surface of the anchor wire, and a second sidewall extending from the floor to the first surface of the anchor wire, the first and second sidewalls of the first grooves being perpendicular to the floor of the first grooves, and wherein each of the second grooves comprises a floor, a first sidewall extending from the floor to the second surface of the anchor wire, and a second sidewall extending from the floor to the second surface of the anchor wire, the first and second sidewalls of the second grooves being perpendicular to the floor of the second grooves.
The toothbrush according to claim 2 wherein each of the first grooves has a first groove depth measured from the floor of the first groove to the first surface of the anchor wire and wherein each of the second grooves has a second groove depth measured from the floor of the second groove to the second surface of the anchor wire, the first and second groove depths being the same.
The toothbrush according to claim 3 wherein a ratio of the groove width to each of the first and second groove depths is between 5∶1 and 8∶1.
The toothbrush according to any one of claims 1 to 4 wherein one of the first grooves adjacent to the bottom end of the anchor wire and one of the second grooves adjacent to the bottom end of the anchor wire are spaced apart from the bottom end of the anchor wire by a groove to end spacing distance, and wherein the groove width and the groove to groove spacing distance are greater than the groove to end spacing distance.
The toothbrush according to claim 5 wherein a ratio of the groove width to the groove to end spacing distance is between 1.1∶1 and 1.3.1, and wherein a ratio of the groove to groove spacing distance and the groove to end spacing distance is between 1.1∶1 and 1.3∶1.
The toothbrush according to any one of claims 1 to 6 wherein each of the anchor wires comprises a length measured from the bottom end to the top end and a width measured from a first side end to a second side end, the width being greater than the length.
The toothbrush according to any one of claims 1 to 7 wherein the body extends along a longitudinal axis from a proximal end to a distal end, and wherein each of the anchor wires is positioned within one of the tuft holes so that the groove axes of the first and second grooves of the anchor wires intersect the longitudinal axis of the body portion at an oblique angle.
The toothbrush according to claim 8 wherein the oblique angle is between 10° and 20°.
The toothbrush according to any one of claims 1 to 9 wherein for each of the anchor wires, each of the first grooves in the first surface of the anchor wire is aligned with one of the second grooves in the second surface of the anchor wire.
The toothbrush according to any one of claims 1 to 10 wherein each of the anchor wires comprises a thickness measured from the first surface to the second surface, and wherein each of the first and second grooves has a depth, and wherein a ratio of the thickness of the anchor wire to the depth of the first and second grooves is greater than 4∶1 and less than 6∶1.
The toothbrush according to any one of claims 1 to 11 wherein each of the anchor wires comprises a thickness measured from the first surface to the second surface, and wherein the groove width is greater than the thickness.
The toothbrush according to any one of claims 1 to 12 wherein the metal alloy comprises nickel, copper, and zinc, the nickel comprising 8-15wt%of the metal alloy and the copper comprising 50-70wt%of the metal alloy.
The toothbrush according to claim 13 wherein the nickel comprises 11-12wt%of the metal alloy and the copper comprises 61-62wt%of the metal alloy.
The toothbrush according to any one of claims 1 to 14 wherein the groove width is approximately 0.3mm, wherein the groove to groove spacing distance is approximately 0.3mm, wherein a thickness of the anchor wire measured from the first surface to the second surface is approximately 0.28mm, wherein a depth of the first and second grooves is approximately 0.05mm, and wherein a distance between the first and second grooves positioned closest to the bottom and top ends of the anchor wire and the bottom and top ends of the anchor wire is approximately 0.25mm.
A toothbrush comprising:

a body comprising a handle portion and a head portion comprising a front surface, the body formed from a cellulosic material;

a plurality of tuft holes formed into the front surface of the head portion, each of the tuft holes comprising a floor that is recessed relative to the front surface of the head portion;

a bristle tuft positioned within each of the tuft holes;

an anchor wire positioned within each of the tuft holes to secure the bristle tufts to the head portion, each of the anchor wires formed from a metal alloy comprising nickel;

each of the anchor wires comprising a bottom end adjacent to the floor of the tuft hole within which the anchor wire is positioned, a top end opposite the bottom end, a first anchor wire axis extending from the bottom end to the top end, and first and second surfaces extending from the bottom end to the top end;

a plurality of first grooves formed into the first surface of each of the anchor wires and a plurality of second grooves formed into the second surface of each of the anchor wires, each of the first and second grooves extending along a groove axis that is perpendicular to the first anchor wire axis; and

wherein each of the first grooves comprises a floor, a first sidewall extending from the floor to the first surface of the anchor wire, and a second sidewall extending from the floor to the first surface of the anchor wire, the first and second sidewalls being perpendicular to the floor, and wherein each of the second grooves comprises a floor, a first sidewall extending from the floor to the second surface of the anchor wire, and a second sidewall extending from the floor to the second surface of the anchor wire, the first and second sidewalls being perpendicular to the floor.
The toothbrush according to claim 16 wherein each of the first grooves and each of the second grooves has a groove width measured in a direction parallel to the first anchor wire axis, wherein each of the first grooves is spaced apart from each adjacent one of the first grooves and each of the second grooves is spaced apart from each adjacent one of the second grooves by a groove to groove spacing distance, and wherein the groove width and the groove to groove spacing distance are the same.
The toothbrush according to claim 17 wherein each of the first grooves and each of the second grooves comprises a groove depth, and wherein a ratio of the groove width to the groove depth is between 5∶1 and 8∶1.
The toothbrush according to claim 17 or claim 18 wherein the plurality of first grooves comprises a first end groove spaced a first groove to end spacing distance from the bottom end of the anchor wire and a second end groove spaced a second groove to end spacing distance from the top end of the anchor wire, and wherein the groove width and the groove to groove spacing distance are greater than the first and second groove to end spacing distances.
The toothbrush according to claim 19 wherein a ratio of the groove width to each of the first and second groove to end spacing distances is between 1.1∶1 and 1.3∶1.
The toothbrush according to any one of claims 16 to 20 wherein the cellulosic material comprises bamboo.
The toothbrush according to any one of claims 16 to 21 wherein each of the anchor wires comprises a thickness measured from the first surface to the second surface, and wherein each of the first grooves and each of the second grooves has a groove width measured in a direction parallel to the first anchor wire axis, and wherein the groove width is greater than the thickness.
A toothbrush comprising:

a body comprising a handle portion and a head portion comprising a front surface, the body formed from bamboo;

a plurality of tuft holes formed into the front surface of the head portion, each of the tuft holes comprising a floor that is recessed relative to the front surface of the head portion;

a bristle tuft positioned within each of the tuft holes;

an anchor wire positioned within each of the tuft holes to secure the bristle tufts to the head portion, each of the anchor wires formed from a metal alloy comprising nickel;

each of the anchor wires comprising a bottom end adjacent to the floor of the tuft hole within which the anchor wire is positioned, a top end opposite the bottom end, a first anchor wire axis extending from the bottom end to the top end, first and second surfaces extending from the bottom end to the top end, and a thickness measured from the first surface to the second surface;

a plurality of first grooves formed into the first surface of each of the anchor wires and a plurality of second grooves formed into the second surface of each of the anchor wires, each of the first and second grooves extending along a groove axis that is perpendicular to the first anchor wire axis; and

wherein each of the first and second grooves has a groove width measured in a direction parallel to the first anchor wire axis, wherein the groove width is greater than the thickness of the anchor wire.
An anchor wire for securing bristle tufts to a toothbrush made from a cellulosic material, the anchor wire comprising:

an anchor body formed from a metal alloy comprising nickel, copper, and zinc, the anchor body comprising a bottom end, a top end, a first surface, and a second surface, a first anchor axis extending from the bottom end to the top end;

a plurality of first grooves formed into the first surface of the anchor body and extending along a first groove axis that is perpendicular to the first anchor axis, the plurality of first grooves positioned in a spaced apart manner such that adjacent ones of the first grooves are spaced apart by a first groove to groove spacing distance, each of the first grooves having a first groove width measured in a direction parallel to the first anchor axis;

a plurality of second grooves formed into the second surface of the anchor body and extending along a second groove axis that is perpendicular to the first anchor axis, the plurality of second grooves positioned in a spaced apart manner such that adjacent ones of the second grooves are spaced apart by a second groove to groove spacing distance, each of the second grooves being in alignment with one of the first grooves, each of the second grooves having a second groove width measured in a direction parallel to the first anchor axis;

each of the first grooves comprising a floor, a first sidewall extending from the floor to the first surface of the anchor body, and a second sidewall extending from the floor to the first surface of the anchor body, the first and second sidewalls being perpendicular to the floor;

each of the second grooves comprising a floor, a first sidewall extending from the floor to the second surface of the anchor body, and a second sidewall extending from the floor to the second surface of the anchor body, the first and second sidewalls being perpendicular to the floor; and

wherein the first and second groove widths and the first and second groove to groove spacing distances are the same.
The anchor wire according to claim 24 wherein the plurality of first grooves comprises a first end groove spaced a first groove to end spacing distance from the bottom end of the anchor wire and a second end groove spaced a second groove to end spacing distance from the top end of the anchor wire, and wherein the first and second groove widths and the first and second groove to groove spacing distances are greater than the first and second groove to end spacing distances.
The toothbrush according to claim 25 wherein a ratio of the first groove width to the first groove to end spacing distance and a ratio of the second groove width to the second groove to end spacing distance is between 1.1∶1 and 1.3∶1.
The anchor wire according to any one of claims 24 to 26 wherein each of the first grooves has a first groove depth measured from the floor of the first groove to the first surface of the anchor wire, wherein each of the second grooves has a second groove depth measured from the floor of the second groove to the second surface of the anchor wire, and wherein a ratio of the first groove width to the first groove depth and of the second groove width to the second groove depth is between 5∶1 and 8∶1.
The anchor wire according to any one of claims 24 to 27 wherein the anchor body comprises a thickness measured from the first surface of the anchor body to the second surface of the anchor body, and wherein the first and second groove widths are greater than the thickness of the anchor wire.
The anchor wire according to any one of claims 24 to 28 wherein the metal alloy comprises 8-15wt%nickel and 50-70wt%copper.
The toothbrush according to claim 29 wherein the metal alloy comprises 11-12wt%nickel and 61-62wt%copper.