Toothbrush and Anchor Wire Therefor

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 (Ti) of the anchor wire (200).

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.

DETAILED DESCRIPTION

Referring first toFIG.1, a toothbrush100is illustrated in accordance with an embodiment of the present invention. The toothbrush100comprises a body101having a handle portion110and a head portion120. The body101is a single, unitary construction such that the handle portion110and the head portion120are part of the same monolithic component. The body101may 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 body101in some embodiments is formed from bamboo and in other embodiments is formed from wood, but in accordance with the exemplified embodiment the body101is 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 body101extends from a proximal end102(which forms a proximal end of the handle portion110) to a distal end103(which forms a distal end of the head portion120) along a longitudinal axis A-A. As noted above, the handle portion110and the head portion120may be formed as an integral unitary structure, although in other embodiments it may be possible for the head portion120to be detachable from the handle portion110so that the head portion120can be replaced when the bristles thereon become worn. Thus, in the exemplified embodiment a distal end104of the handle portion110is coupled directly to a proximal end105of the head portion120as a one-piece unit.

The handle portion110is the portion of the body101that is gripped by a user during use thereof. Thus, the handle portion110preferably has a length and width that is selected for user comfort so that a user can clasp his/her hand around the handle portion110to use the toothbrush100for oral cavity treatment such as toothbrushing. The handle portion110is elongated and may have various contours to enhance user comfort. In the exemplified embodiment, the side surfaces of the handle portion110may be wavy to allow the handle portion110to sit more comfortably within a user's palm and fingers. The handle portion110may have flat front and rear surfaces and/or may include bumps, ridges, or protrusions to enhance grip. The handle portion110may 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 portion110are 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 portion110shown in the drawings in all embodiments. In some embodiments, the cellulosic material (e.g., wood, bamboo) that forms the body101may be coated with beeswax to prevent mold growth and prolong the life of the body101as it is normally used under wet conditions.

Referring toFIGS.1-4, the head portion120will be described. The head portion120extends from the proximal end105where it is connected to the handle portion110to the distal end103of the body101which is also the distal end of the head portion120. The head portion120extends along the longitudinal axis A-A of the body101. The head portion120comprises a front surface123, a rear surface124opposite the first surface123, and a peripheral surface125extending between the front and rear surfaces123,124. The region where the peripheral surface125intersects the front surface123may be referred to herein as a perimeter128of the head portion120.

A plurality of tuft holes130are formed into the front surface123of the head portion120, the details of which are best shown inFIG.4. Each of the tuft holes130is a hole formed into the front surface123of the head portion120having a height that is less than a thickness of the head portion120measured between the front and rear surfaces123,124of the head portion120. Thus, each of the tuft holes130comprises a floor131that is recessed relative to the front surface123of the head portion120and a sidewall132that extends from the floor131to the front surface123of the head portion120. The tuft holes130do not extend entirely through the head portion120to the rear surface124. Thus, while the tuft holes130have openings in the front surface123of the head portion120, there are no openings to the tuft holes130in the rear surface124of the head portion. The tuft holes130have round cross-sectional areas in the exemplified embodiment, but they could take on other shapes in other embodiments. The tuft holes130may have a diameter of between 1.2 and 2.0 mm, 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 holes130may all have the same diameter or there may be tuft holes130with different diameters formed into the head portion120. The tuft holes130are arranged on the front surface123of the head portion120in 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 holes130is not to be limiting of the invention in all embodiments.

In the exemplified embodiment, a plurality of bristle tufts151are anchored to the head portion120of the body101so that each of the bristle tufts151extends from the front surface123of the head portion120. Specifically, in the exemplified embodiment one of the bristle tufts151is positioned within each of the tuft holes130. Only a few of the bristle tufts151are labeled inFIGS.1-3in order to prevent clutter. Each of the plurality of bristle tufts151is located within one of the tuft holes130in the head portion120and secured thereto by an anchor wire200. The bristle tufts151collectively define a bristle field150.

Each of the bristle tufts151comprises a plurality of bristles that are clumped together to form the bristle tuft151, which is then inserted into a singular tuft hole formed into the head portion120. The bristles within each of the bristle tufts151may 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 tuft151or each bristle tuft151may 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 tufts151may 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 toothbrush100for oral hygiene activities.

In the exemplified embodiment, to secure the bristle tufts151to the head portion120, the bristle tufts151are folded into a U shape and then driven into the tuft hole130with the anchor wire200. Thus, the anchor wire200rests atop a bight portion155of the U shape of the bristle tufts151and sandwiches the bight portion155between the anchor wire200and the floor131of the tuft hole130. Thus, the anchor wire200is not driven so far into the tuft hole130so as to make contact with the floor131, but rather the anchor wire200remains spaced from the floor131of the tuft hole130so that the bristles of the bristle tuft151can pass underneath the anchor wire200between the anchor wire200and the floor131of the tuft hole130. The anchor wire200may become partially embedded within the material of the head portion120(i.e., within the sidewall132of the tuft hole130) to secure the anchor wire200in place within the tuft hole130. For example, in some embodiments the tuft hole130has a diameter of 1.6 mm and the anchor wire200has a width of 2.2 mm, such that 0.3 mm on each end of the anchor wire200is embedded within the sidewall132of the tuft hole130within which it is positioned. This results in the anchor wire200being securely coupled to the head portion120of the toothbrush100. It should be noted that such embedment of the anchor wire200in the head portion200is not required in all embodiments and it may be possible to secure the anchor wire200to the head portion120via a friction fit between the edges of the anchor wire200and the sidewall132of the tuft hole130, using adhesives, or other technical means. As the anchor wire200is coupled to the head portion120of the toothbrush100, the anchor wire200holds the bristle tuft151in place within the tuft hole130.

One important consideration in toothbrush manufacture is tuft retention, which is a measure of the force required to detach the bristles of the bristle tuft151from the head portion120of the toothbrush100(i.e., the holding force of filament tufts in the head portion120of the toothbrush100). Specifically, if the toothbrush100has poor tuft retention, then the bristles of the bristle tufts151will more readily become detached from the head portion120of the toothbrush100during use whereas if the toothbrush100has good tuft retention the bristles of the bristle tufts151are less likely to become detached from the head portion120of the toothbrush100during use. As will be discussed in greater detail below, the anchor wire200of the invention described herein has been specifically designed to increase tuft retention in the toothbrush100which is formed from a cellulosic material such as wood or bamboo.

In the exemplified embodiment, the bristle tufts151comprising filament bristles are the only tooth cleaning elements coupled to and extending from the head portion120. 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 portion120alongside of the bristle tufts151.

As best seen inFIG.3, in the exemplified embodiment the bristle field150formed by the plurality of bristle tufts151has a flat trim profile. Specifically, each of the bristle tufts151has the same height measured from the front surface123of the head portion120to a distal end152of the bristle tuft151. As a result, the distal ends152of the bristle tufts151collectively lie on a common plane that is parallel to the front surface123of the head portion120. However, the invention is not to be so limited in all embodiments and in some other embodiments the bristle tufts151may 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 holes130and the bristle tufts151are not to be limiting of the present invention in all embodiments and may be modified to suit a particular purpose.

Referring toFIGS.5and6, the anchor wire200that may be used to secure the bristle tufts151within the tuft holes130of the toothbrush100will be described in greater detail. The anchor wires200may comprise an anchor body250. One of the anchor wires200is inserted within each of the tuft holes130that contains a bristle tuft150in order to secure the bristle tuft150within the tuft hole130with sufficient retention so that limited, if any, bristles of the bristle tuft150are removed during normal use of the toothbrush100. The use of the anchor wires200for securing the bristle tufts151to the head portion120of the toothbrush100is commonly referred to as a staple technique. Basically, the bristle tufts151are bent into a U shape around the anchor wire200to form a bristle-anchor wire subassembly. The bristle-anchor wire subassembly is then placed into the tuft holes130. The engagement between the anchor wire200and the head portion120of the toothbrush100(via embedment of the anchor wire200as described above, friction, or any other technical means) ensures that the bristle tufts151are retained within the tuft holes130. The ability of the anchor wires200to remain in place assists with bristle retention by preventing bristles from being detached from the head portion120during normal use of the toothbrush100.

In accordance with the invention set forth herein, the anchor wires200may be formed from a metal alloy that comprises nickel. In some embodiments, the anchor wire200may 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 8-15 wt % nickel and 50-70 wt % copper. In another more particular embodiment, the metal alloy may comprise 11-12 wt % nickel and 61-62 wt % 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 0.1 wt % and 2 wt %, or approximately 0.3 wt % 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 wires200of the toothbrush100comprises at least 10 wt % 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 wire200described herein is formed from a metal alloy comprising nickel and excluding brass (as compared to the metal alloy comprising brass). The graph shown inFIG.9and described below further illustrates the increased tuft retention with the anchor wire200formed from a metal alloy that comprises nickel.

In the exemplified embodiment, the anchor wire200is a double sided grooved anchor having grooves on opposing major surfaces, with the grooves being square or rectangular shaped. The anchor wire200has a generally rectangular shape, although the shape and dimensions of the tuft hole within which the anchor wire200is to be positioned may dictate varying the shape of the anchor wire200as should be appreciated. The anchor wire200comprises a bottom end201, a top end202, a first surface203extending from the bottom end201to the top end202, a second surface204extending from the bottom end201to the top end202, a first side end205extending between the bottom and top ends201,202and between the first and second surfaces203,204, and a second side end206extending between the bottom and top ends201,202and between the first and second surfaces203,204. The first and second surfaces203,204may be considered the major surfaces of the anchor wire200because they are the surfaces having the largest surface area. The anchor wire200extends from the bottom end201to the top end202along a first anchor wire axis B-B and from the first side end205to the second side end206along 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 ends201,202are chamfered. That is, the top end201comprises an end wall281, a first oblique wall282extending from the end wall281to the first surface203, and a second oblique wall283extending from the end wall281to the second surface204. Each of the first and second oblique walls282,283intersects the end wall281at an oblique angle, which in the exemplified embodiment is an obtuse angle. Similarly, the bottom end202comprises an end wall292, a first oblique wall292extending from the end wall281to the first surface203, and a second oblique wall293extending from the end wall291to the second surface204. Each of the first and second walls292,293intersects the end wall291at 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 surfaces203,204.

There are multiple benefits to the chamfering of the top end202, and more particularly the bottom end201. First, this reduces the likelihood that the anchor wire200will break the bristles of the bristles tufts151as the subassembly is being inserted into the tuft holes130. Specifically, because the bristles are able to wrap around the first and second oblique walls292,293, the corner that contacts the bristles (i.e., the corner between the first and second oblique walls292,293and the end wall291) is not as sharp as it would be if the oblique walls292,293were omitted and the first and second surfaces203,204instead connected directly to the end wall291. Furthermore, as noted herein, the anchor wire200is 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 wires200into the tuft holes130does not cause the cellulosic material of the head portion120of the toothbrush100to split or otherwise become damaged.

Referring briefly toFIGS.4and7A, the anchor wire200is positioned in the tuft hole130so that the bottom end201of the anchor wire200is adjacent to the floor131of the tuft hole130, although the bottom end201of the anchor wire200is spaced apart from the floor131of the tuft hole130so that the bristles can pass through the space between the anchor wire200and the floor131. The top end202of the anchor wire200is recessed relative to the front surface123of the head portion120. The first and second side ends205,206of the anchor wire200are either abutted against or embedded within the sidewalls132of the tuft holes130(best shown inFIG.7described below) to couple the anchor wire200to the head portion120of the toothbrush100.

Referring again toFIGS.5and6, the anchor wire200has a length L1measured from the bottom end201to the top end202and a width W1measured from the first side end205to the second side end206. In the exemplified embodiment, the width W1is greater than the length L1. In some embodiments, the width W1may be between 2.0 mm and 2.4 mm, and more specifically approximately 2.2 mm. Furthermore, the length L1may be between 1.8 mm and 2.2 mm, and more specifically approximately 2.0 mm. The anchor wire200also has a thickness T1measured from the first surface203to the second surface204. In the exemplified embodiment, the thickness T1is between 0.26 mm and 0.30 mm, and more specifically approximately 0.28 mm. 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 L1may be exactly 2.2 mm, the width W1may be exactly 2.0 mm, and the thickness T1may be exactly 0.28 mm.

The anchor wire200comprises a plurality of first grooves210formed into the first surface203and a plurality of second grooves220formed into the second surface204. Each of the first grooves210extends 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 grooves210,220extends from the first side end205of the anchor wire200to the second side end206of the anchor wire200. Thus, each of the plurality of first grooves210and each of the plurality of second grooves220extend an entirety of the width W1of the anchor wire200from the first side end205to the second side end206. Each of the first and second grooves210,220has a length measured in a direction of the groove axis D-D that is identical to the width W1of the anchor wire200.

Furthermore, because the anchor wire200is positioned within the tuft holes130with the bottom end201of the anchor wire200adjacent to the floor131of the tuft hole130, the first and second grooves210,220extend horizontally in a direction that is parallel to the plane of the head portion120and perpendicular to the axis of the tuft hole130. This creates additional friction between the anchor wire200and the sidewalls132of the tuft hole130. Each of the second grooves220is aligned with one of the first grooves210, as best shown inFIG.6. Thus, moving in a direction from the bottom end201of the anchor wire200to the top end202of the anchor wire200, wherever there is a first groove210in the first surface203there is also a second groove220in the second surface204. Stated another way, any axis that is perpendicular to both of the first and second surfaces203,204of the anchor wire200which intersects one of the first grooves210will also intersect one of the second grooves220, and vice versa. Any axis that is perpendicular to both of the first and second surfaces203,204of the anchor wire200which does not intersect one of the first grooves210will also not intersect one of the second grooves220.

Each of the first grooves210comprises a floor211, a first sidewall212extending from the floor211to the first surface203, and a second sidewall213extending from the floor211to the first surface203. The floor211is recessed relative to the first surface203of the anchor wire200. The first and second sidewalls212,213are perpendicular to the floor211, which gives the first grooves210their square or rectangular shape. Thus, a 90° angle is formed at the intersection of the floor211and the first and second sidewalls212,213of the first grooves210, although the corners where the first and second sidewalls212,213intersect the floor211could be somewhat rounded due to the manufacturing process as shown inFIG.6. Regardless, the first and second sidewalls212,213still extend perpendicularly relative to the floor211.

The first grooves210have a first groove depth D1measured from the floor211of the first groove210to the first surface203of the anchor wire200. In the exemplified embodiment, the first groove depth D1is approximately 0.05 mm (the term approximately including a tolerance of plus/minus 5%).

The first grooves210have a first groove width WG1measured from the first sidewall212to the second sidewall213. Thus, the first groove width WG1is 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 grooves210has the same first groove width WG1. In the exemplified embodiment, the first groove width WG1may be between 0.28 mm and 0.32 mm, and more specifically approximately 0.30 mm. 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 WG1is greater than the thickness T1of the anchor wire200.

The first grooves210are spaced apart from one another by a first groove to groove spacing distance D2. The first groove to groove spacing distance D2is the distance between one of the first grooves210and an immediately adjacent one of the first grooves210measured in a direction of the first anchor wire axis B-B. The first groove to groove spacing distance D2only includes space between adjacent ones of the first grooves210and does not include any portion of the width of the first grooves210. In the exemplified embodiment, the first groove to groove spacing distance D2may be between 0.28 mm and 0.32 mm, and more specifically approximately 0.30 mm (with approximately including a tolerance of plus/minus 5%). Thus, in the exemplified embodiment the first groove width WG1and the first groove to groove spacing distance D2are the same, or substantially equal (with the term substantially allowing for a tolerance such that one of the first groove width WG1and the first groove to groove spacing distance D2may be up to 5% greater than the other).

Furthermore, the plurality of first grooves210comprises end-most grooves that are positioned closest to the bottom and top ends201,202of the anchor wire200. The end-most groove closest to the bottom end201of the anchor wire200is spaced apart from the bottom end201of the anchor wire200by a first groove to end spacing distance D3. Although not shown in the drawings, the end-most groove closest to the top end202of the anchor wire200is also spaced apart from the top end202of the anchor wire200by the first groove to end spacing distance D3. In the exemplified embodiment, the first groove to end spacing distance D3is between 0.22 mm and 0.28 mm, and more specifically approximately 0.25 mm (approximately including a tolerance of plus/minus 5%).

In one specific embodiment of the invention, the anchor wire200may have the following dimensions: the first groove width WG1of approximately 0.3 mm, the first groove to groove spacing distance D2of approximately 0.3 mm, the thickness T1of approximately 0.28 mm, the first groove depth D1of approximately 0.05 mm, and the first groove to end spacing distance D3of approximately 0.25 mm.

Thus, in certain embodiments, the first groove width WG1and the first groove to groove spacing distance D2are the same. Furthermore, the first groove width WG1and the first groove to groove spacing distance D2are greater than the first groove to end spacing distance D3. A ratio of the first groove width WG1to the first groove to end spacing distance D3may be between 1.1:1 and 1.3:1. Moreover, in some embodiments a ratio of the first groove width WG1to the first groove depth D1may 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 T1of the anchor wire200to the first groove depth D1may be greater than 4:1 and less than 6:1.

The second grooves220have an identical structure, shape, size, and the like as the first grooves210. Each of the second grooves220comprises a floor221, a first sidewall222extending from the floor221to the second surface204, and a second sidewall223extending from the floor221to the second surface204. The floor221is recessed relative to the second surface204of the anchor wire200. The first and second sidewalls222,223are perpendicular to the floor221. Thus, a 90° angle is formed at the intersection of the floor221and the first and second sidewalls222,223of the second grooves220, although the corners where the first and second sidewalls222,223intersect the floor221could be somewhat rounded due to the manufacturing process as shown inFIG.6. Regardless, the first and second sidewalls222,223still extend perpendicularly relative to the floor221.

The second grooves220have a second groove depth D4measured from the floor221of the second groove220to the second surface204of the anchor wire200. In the exemplified embodiment, the second groove depth D4is approximately 0.05 mm (approximately including a tolerance of plus/minus 5%). The second groove depth D4of the second grooves220may be the same as the first groove depth D1of the first grooves210.

The second grooves220have a second groove width WG2measured from the first sidewall222to the second sidewall223in 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 grooves220has the same second groove width WG2. In the exemplified embodiment, the second groove width WG2may be between 0.28 mm and 0.32 mm, and more specifically approximately 0.30 mm. 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 WG2may be identical to the first groove width WG1and may be greater than the thickness T1.

The second grooves220are spaced apart from one another by a second groove to groove spacing distance D5. The second groove to groove spacing distance D5is the distance between one of the second grooves220and an immediately adjacent one of the second grooves220in a direction of the first anchor axis B-B. The second groove to groove spacing distance D5only includes space between adjacent ones of the second grooves220and does not include any portion of the width of the second grooves220. In the exemplified embodiment, the second groove to groove spacing distance D5may be between 0.28 mm and 0.32 mm, and more specifically approximately 0.30 mm (with approximately including a tolerance of plus/minus 5%). Thus, in the exemplified embodiment the second groove width WG2and the second groove to groove spacing distance D5are the same or substantially equal (with the term substantially allowing for a tolerance such that one of the second groove width WG2and the second groove to groove spacing distance D5may be up to 5% greater than the other). The second groove width WG2may also be the same as the first groove width WG1and the second groove to groove spacing distance D5may be the same as the first groove to groove spacing distance D2.

Furthermore, the plurality of second grooves220comprises end-most grooves that are positioned closest to the bottom and top ends201,202of the anchor wire200. The end-most one of the second grooves closest to the bottom end201of the anchor wire200is spaced apart from the bottom end201of the anchor wire200by 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 end202of the anchor wire200is also spaced apart from the top end202of the anchor wire200by the second groove to end spacing distance D6. In the exemplified embodiment, the second groove to end spacing distance D6is between 0.22 mm and 0.28 mm, and more specifically approximately 0.25 mm (approximately including a tolerance of plus/minus 5%). Thus, the dimensions of the second grooves220and the spacing therebetween and relative to the bottom and top ends201,202are identical to that which was provided above for the first grooves210. In the exemplified embodiment, the second groove to end spacing distance D6is the same as the first groove to end spacing distance D3.

In one specific embodiment of the invention, the anchor wire200may have the following dimensions: the second groove width WG2of approximately 0.3 mm, the second groove to groove spacing distance D5of approximately 0.3 mm, the thickness T1of approximately 0.28 mm, the second groove depth D4of approximately 0.05 mm, and the second groove to end spacing distance D6of approximately 0.25 mm.

Thus, in certain embodiments, the second groove width WG2and the second groove to groove spacing distance D5are the same. Furthermore, the second groove width WG2and the second groove to groove spacing distance D5are greater than the second groove to end spacing distance D6. A ratio of the second groove width WG2to the second groove to end spacing distance D6may be between 1.1:1 and 1.3:1. Moreover, in some embodiments a ratio of the second groove width WG2to the second groove depth D2may 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 T1of the anchor wire200to the second groove depth D4may be greater than 4:1 and less than 6:1.

In certain embodiments, the anchor wire200may have a second thickness T2measured from the floor211of one of the first grooves210to the floor221of the one of the second grooves220that is aligned with the first groove210. A ratio of the second thickness T2to 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 T1of the anchor wire200to the second thickness T2may 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 WG1or the second groove width WG2to the thickness T2may be in a range of 1.5:1 and 1.8:1, and more specifically between 1.6:1 and 1.7:1.

Referring toFIG.7, the head portion120of the toothbrush100is illustrated with the bristle tufts omitted. Furthermore, inFIG.7one of the anchor wires200is illustrated positioned within each of the tuft holes130. In the exemplified embodiment, each of the anchor wires200is positioned within one of the tuft holes130in the same orientation. Thus, the second anchor axes C-C of each of the plurality of anchor wires200are parallel to one another when the anchor wires200are disposed within the tuft holes130. Furthermore, although not shown, the groove axes D-D are parallel to the second anchor axes C-C and thus are oriented as shown inFIG.7as well. Moreover, each of the anchor wires200is positioned within one of the tuft holes130so that the second anchor axes C-C and the groove axes D-D are oblique to the longitudinal axis A-A of the toothbrush100and the head portion120thereof. More specifically, the second anchor axes C-C and the groove axes D-D of the anchor wires200form an oblique angle θ1with the longitudinal axis A-A of the head portion120of at least 10 degrees. In other embodiments, the oblique angle θ1is at least 15 degrees. In some embodiments, the oblique angle θ1is 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.8illustrates an anchor wire300of the prior art that is previously known to have been used on toothbrushes formed from cellulosic material such as bamboo. The anchor wire300ofFIG.8is formed from brass or a metal alloy comprising brass and devoid of nickel. The anchor wire300is a double grooved anchor wire in that it has grooves on both faces thereof similar to the anchor wire200. However, the sidewalls of the grooves of the anchor wire300are not perpendicular to the floor of the grooves of the anchor wire300. 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 wire200from a metal alloy comprising nickel and such that the first and second grooves210,220have walls that are perpendicular to its floor has resulted in the toothbrush100having an improved tuft retention due to the stronger nickel material and an increased friction between the anchor wire200and the sidewall132of the tuft hole130.

Referring toFIG.9, a graph illustrating the tuft retention for the toothbrush100formed from bamboo using the anchor wire300ofFIG.8and using the anchor wire200ofFIGS.5and6is provided. As can be seen, the average tuft retention with the anchor wire200is 41.6 N whereas the average tuft retention with the anchor wire300is 30.4. This illustrates that there is a significant improvement in tuft retention when the anchor wire300is used in the toothbrush100to hold the bristle tufts150in the tuft holes130as compared to when the anchor wire200of the prior art is used in the toothbrush100to hold the bristle tufts150in the tuft holes130.