EYELASH CURLER AND METHOD OF USING SAME

Abstract

An eyelash curling device is adapted to curl a user's eyelashes and includes a first arm having a first end and a second end, a second arm having a first end and a second end, the second arm joined to the first arm, and an applicator including an upper shell that is attached to the first end of the first arm, and a lower shell that is attached to the first end of the second arm. A surface of the upper shell may have a concave shape that extends about 90 degrees or greater from one side to another side. A surface of the lower shell may have a concave shape that extends about 101 degrees or greater from one side to another side.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A COMPACT DISK APPENDIX

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The following description relates to an eyelash curling device or eyelash curler. Also, a method of using an eyelash curler is described. For example, an eyelash curler is a cage-free curler having an applicator with upper and lower shells having outer surfaces forming concave semi-circular shapes.

2. Related Art

Eyelash curling devices are used for the curling of a user's eyelashes to embellish the appearance of the eyelashes. Typical curlers may include two arms that are separable for opening and closing two eyelash curling elements that receive a user's eyelashes. As the user presses on the eyelashes, the eyelashes become more curved and have a fuller appearance. Typical curlers include a cage element that is formed by the connection of the arms with the eyelash curling elements at the front of the curlers. Eyelash curlers are typically curved in shape and form a concave outer surface for curling the eyelashes. Eyelash curling elements are typically short in height and extend a short distance about a concave curvature.

SUMMARY OF THE INVENTION

In an aspect, an apparatus adapted to curl a user's eyelashes includes a first arm having a first end and a second end, a second arm having a first end and a second end, the second arm joined to the first arm, and an applicator including an upper shell that is attached to the first end of the first arm, and a lower shell that is attached to the first end of the second arm, wherein a surface of the upper shell is configured to face the user's eyelashes and has a concave curve that extends approximately 90 degrees or greater from one side to another side.

In another aspect, an apparatus adapted to curl a user's eyelashes includes a first arm having a first end and a second end, a second arm having a first end and a second end, the second arm joined to the first arm, and an applicator including an upper shell that is attached to the first end of the first arm, and a lower shell that is attached to the first end of the second arm, where a surface of the lower shell is configured to face the user's eyelashes and has a concave curve that extends approximately 101 degrees or greater from one side to another side.

In yet another aspect, an apparatus adapted to curl a user's eyelashes includes a first arm having a first end and a second end, a second arm having a first end and a second end, the second arm joined to the first arm, and an applicator including an upper shell that is attached to the first end of the first arm; and a lower shell that is attached to the first end of the second arm, where an edge of the upper shell comprises a first endpoint, a second endpoint, and a midpoint, and a line extending through the first endpoint and the midpoint forms an acute angle with a line that is parallel to an extension of the first end of the first arm.

DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The foregoing summary, as well as the following detailed description, will be better understood when read in conjunction with the appended drawings. For the purpose of illustration, there is shown in the drawings certain embodiments of the present disclosure. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an implementation of systems and apparatuses consistent with the present invention and, together with the description, serve to explain advantages and principles consistent with the invention.

FIG. 1 is a diagram illustrating a perspective view of an example of an eyelash curler including an applicator having an upper shell and a lower shell.

FIG. 2 is a diagram illustrating a front elevation view of the example of the eyelash curler including the applicator having the upper shell and the lower shell.

FIG. 3 is a diagram illustrating a back elevation view of the example of the eyelash curler including the applicator having the upper shell and the lower shell.

FIG. 4 is a diagram illustrating a top elevation view of the example of the eyelash curler including the applicator having the upper shell and the lower shell.

FIG. 5 is a diagram illustrating a bottom elevation view of the example of the eyelash curler including the applicator having the upper shell and the lower shell.

FIG. 6 is a diagram illustrating a side elevation view of the example of the eyelash curler including the applicator having the upper shell and the lower shell.

FIG. 7 is a diagram illustrating a front elevation view of the example of the applicator having the upper shell and the lower shell.

FIG. 8 is a diagram illustrating a top elevation view of the example of the applicator having the upper shell and the lower shell.

FIG. 9 is a diagram illustrating a back elevation view of the example of the applicator having the upper shell and the lower shell.

FIG. 10 is a diagram illustrating a side elevation view of the example of the applicator having the upper shell and the lower shell.

FIG. 11 is a diagram illustrating a cross section of the example of the applicator having the upper shell and the lower shell along the line 11-11 as illustrated in FIG. 7.

FIG. 12 is a diagram illustrating a side elevation view of the example of the eyelash curler including the applicator in a closed configuration.

FIG. 13 is a diagram illustrating a side elevation view of the example of the applicator having the upper shell and the lower shell in an open configuration

FIG. 14 is a diagram illustrating a side perspective view of the example of the applicator having the upper shell and the lower shell in an open configuration.

FIG. 15 is a diagram illustrating a perspective view of the upper shell of the applicator.

FIG. 16 is a diagram illustrating a common shape of an eyelid of a user of the eyelash curler.

DETAILED DESCRIPTION OF THE INVENTION

Before explaining at least one example of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The Figures and written description are provided to teach any person skilled in the art to make and use the inventions for which patent protection is sought. The invention is capable of other embodiments and of being practiced and carried out in various ways. Those skilled in the art will appreciate that not all features of a commercial embodiment are shown for the sake of clarity and understanding. Persons of skill in the art will also appreciate that the development of an actual commercial embodiment incorporating aspects of the present inventions will require numerous implementation—specific decisions to achieve the developer's ultimate goal for the commercial embodiment. While these efforts may be complex and time-consuming, these efforts nevertheless would be a routine undertaking for those of skill in the art having the benefit of this disclosure.

In addition, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. For example, the use of a singular term, such as, “a” is not intended as limiting of the number of items. Also the use of relational terms, such as but not limited to, “top,” “bottom,” “left,” “right,” “upper,” “lower,” “down,” “up,” “side,” are used in the description for clarity in specific reference to the Figures and are not intended to limit the scope of the invention or the appended claims. Further, it should be understood that any one of the features of the invention may be used separately or in combination with other features. Other systems, methods, features, and advantages of the invention will be or become apparent to one with skill in the art upon examination of the Figures and the detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the present invention, and be protected by the accompanying claims. The terms “approximately” or “about” as used throughout the specification and the claims of this application are hereby defined to mean plus or minus five percent (5%) of a given value.

FIG. 1 is a diagram illustrating a perspective view of an example of an eyelash curler 100 including an applicator 110 having an upper shell 112 and a lower shell 114. Referring to FIG. 1, the eyelash curler 100 includes the applicator 110, a first arm 120, and a second arm 130. The first arm 120 includes a first handle 124 and the second arm 130 includes a second handle 134. The first and second handles 124, 134 of this example are plastic and coated with silicone but may be formed of other materials and may have other shapes such as handles with openings as used in conventional scissors.

In this example, the first arm 120 includes a right arm 121 and a left arm 122 that are adjacent and in contact with one another at one end of the eyelash curler 100 that is adjacent to the first handle 124 and diverge to opposite sides as they reach the upper shell 112. The second arm 130 includes a right arm 131 and a left arm 132 that are adjacent and in contact with one another at one end of the eyelash curler 100 that is adjacent to the second handle 134 and diverge to opposite sides as they reach the lower shell 114.

The first arm 120 and the second arm 130 intersect at a point of intersection 150, and the right and left arms 121, 122 of the first arm 120 and the right and left arms 131, 132 of the second arm 130 travel together from one end of the curler 100 until the point of intersection 150. At the point of intersection 150, the first right and left arms 121, 122 cross over the second right and left arms 131, 132 and diverge from one another. The right arm 121 of the first arm 120 extends to a right end of the lower shell 114, the left arm 122 of the first arm 120 extends to a left end of the lower shell 114, the right arm 131 of the second arm 130 extends to a right end of the upper shell 112, and the left arm 132 of the second arm 130 extends to a left end of the upper shell 112.

Still referring to the example illustrated in FIG. 1, the curler 100 also includes a spring element 140. In this example the spring element 140 is attached at one end to the first handle 124 and at the other end to the second handle 134. The spring element 140 maintains a tension that is formed between the first arm 120 and the second arm 130. As the first arm 120 is moved by a user away from the second arm 130, the applicator 110 opens. That is, the first shell 112 is moved away from the second shell 114 to allow a user to insert their eyelashes between the two shells 112, 114. As the first arm 120 is moved back by the user towards the second arm 130, the two shell 112, 114 comes together again to press on the eyelashes and perform the curling function.

The upper shell 112 includes an upper arm receiving member 112a that extends behind the upper shell 112 for receiving the second right and left arms 131, 132. Similarly, the lower shell 114 may include a lower arm receiving member 114a that extends behind the lower shell 114 for receiving the first right and left arms 121, 122. The arm receiving members 112a, 114a may be formed of the same or similar material as the upper and lower shells 112, 114.

FIG. 2 is a diagram illustrating a front elevation view of the example of the eyelash curler 100 including the applicator 110 having the upper shell 112 and the lower shell 114. Referring to FIG. 2, the applicator 110 is shown in a closed configuration where the upper shell 112 and the lower shell 114 are in contact. As also described in reference to FIG. 1, the second right and left arms 131, 132 are shown as extending together until the point of intersection 150 at which point they diverge and extend to opposite ends of the upper shell 112. Because this is a front view, the connection between the second right and left arms 131, 132 and the upper shell 112 is not shown. Further, the first right and left arms 121, 122 are shown diverging at the point of intersection 150 and connecting to opposite ends of the lower shell 114. Because this is a front view, the connection between the first right and left arms 121, 122 and the first handle 124 is not shown while the connection between the second right and left arms 131, 132 and the second handle 134 is shown.

FIG. 3 is a diagram illustrating a back elevation view of the example of the eyelash curler 100 including the applicator 110 having the upper shell 112 and the lower shell 114. Referring to FIG. 3, the first right and left arms 121, 122 are shown as extending together until the point of intersection 150 at which point they diverge and extend to opposite ends of the lower shell 114. The connection between the first right and left arms 121, 122 and the upper shell 112 is shown. Further, the second right and left arms 131, 132 are shown connecting to opposite ends of the upper shell 113. Because this is a back view, the connection between the second right and left arms 131, 132 and the second handle 134 is not shown while the connection between the first right and left arms 121, 122 and the first handle 124 is shown.

Still referring to FIGS. 2 and 3, the applicator 110 in the preferred example does not include a cage. A cage is typically formed by the attachment of arms such as the arms 120, 130 of the curler 100 to the applicator 110. In the preferred example, there is no cage as a result of the attachment mechanism between the arms 120, 130 and the applicator 110 because the arms 120, 130 are positioned entirely behind the upper shell 112 and lower shell 114 such that they do not interfere with the user's eyelashes while the curler 100 is being used.

FIG. 4 is a diagram illustrating a top elevation view of the example of the eyelash curler 100 including the applicator 110 and the upper shell 112. FIG. 5 is a diagram illustrating a bottom elevation view of the example of the eyelash curler 100 including the applicator 110 and the lower shell 114. Referring to FIGS. 4 and 5, the first arm 120, the second arm 130, the right and left arms 121, 122 of the first arm 120, the right and left arms 131, 132 of the second arm 130, the first handle 124, and the second handle 134 are all shown. In addition, referring to FIG. 4, the upper arm receiving member 112a is shown, and referring to FIG. 5, the lower arm receiving member 114a is shown. Further, the concave dimensions of the upper shell 112 and the lower shell 114 are illustrated.

In a preferred example, the upper shell 112 and the lower shell 114 may form a substantially similar concave outer surface for receiving the eyelashes of a user. The upper shell 112 and lower shell 114 may also form different concave surfaces. In this example, the upper shell 112 has a semi-circular shape formed by the circumference of a circle having radius r₁. The angle θ formed by the intersection of the lines normal to the opposite ends 112b, 112c of the upper shell 112 may range from about 70 degrees to about 110 degrees. In the preferred example, the angle θ is about 90 degrees or greater.

Similarly the lower shell 114 has a semi-circular shape formed by the circumference of a circle having radius r₂. The angle α formed by the intersection of the lines normal to the opposite ends 114b, 114c of the lower shell 114 may range from about 80 degrees to about 120 degrees. In the preferred example, the angle α is about 101 degrees or greater.

Still referring to FIG. 5, in an example, the radius r₁ of the upper shell 112 and the radius r₂ of the lower shell 114 are substantially equal but not identical in value. In an example, the radii r₁, r₂ as measured from a top, planar view may range from about 15 mm to about 25 mm but the shapes of the shells 112, 114 are not limited to these dimensions. In a preferred example, the radius r₁ of the upper shell 112 is about 20.6 mm and the radius r₂ of the lower shell 114 is about 20.0 mm.

FIG. 6 is a diagram illustrating a side elevation view of the example of the eyelash curler 100 in a closed configuration including the applicator 110 having the upper shell 112 and the lower shell 114. FIG. 12 is a diagram illustrating a side elevation view of the example of the eyelash curler 100 in an open configuration including the applicator 110 having the upper shell 112 and the lower shell 114.

Referring to FIGS. 6 and 12, the first arm 120, the second arm 130, the right arm 121, 121 of the first arm 120, the right arm 131 of the second arm 130, the first handle 124, and the second handle 134 are all shown. Also, the upper arm receiving member 112a, the lower arm receiving member 114a are shown and attached to the upper shell 112 and lower shell 114, respectively. The spring element 140 is shown being attached to the first handle 124 and the second handle 134. In a preferred example, the attachment of the spring element 140 to the handles 124, 134 is at the interior portion of the handles 124, 134 such that the spring element 140 is embedded between both handles 124, 134.

Referring to FIG. 12, the attachment between the upper shell 112 and the upper arm receiving member 112a forms a first angle β₁ between the back surface of the upper shell 112 and the upper arm receiving member 112a. In turn, this is also the angle between the back surface of the upper shell 112 and the extension of the second arm 130. Similarly, the attachment between the lower shell 114 and the lower arm receiving member 114a forms a second angle β₂ between the back surface of the lower shell 114 and the lower arm receiving member 114a. In turn, this is also the angle between the back surface of the lower shell 114 and the extension of the first arm 120. In this example, the first angle β₁ and the second angle β₂ are equal and about 90 degrees. In other examples, the angles β₁, β₂ are different and may range in value from about 60 degrees to about 120 degrees.

FIGS. 7, 8, 9, 10, and 11 are diagrams illustrating different view of the applicator 100 with the upper shell 112 and the lower shell 114 in a closed configuration. Referring to FIGS. 7-11, the upper shell 112 extends from the first end 112b to the second end 112c to form a concave surface, and includes the for receiving the second arm 130. The lower shell 114 extends from the first end 114b to the second end 114c to form a concave surface, and includes the upper arm receiving member 114a for receiving the second arm 120.

In a preferred example, the lower shell 114 includes a rubber pad 118 and a rib holder 116 for holding the rubber pad 118. Referring the FIG. 11, showing a cross section of the applicator 100 along the line 11-11 as illustrated in FIG. 7, the rubber pad 118 may act to provide a cushion grip to enhance the curling results and/or provide a structural support element that provides a more rigid surface to the lower shell 114. The rubber pad 118 is supported and held in place by the rib holder 116. A height h₁ of the applicator 110 at one end may be approximately the same as the height at the other end and different than a height h₂ at the line 11-11 going through a middle portion of the applicator 110 in a closed configuration. Both the upper surface of the upper shell 112 and the lower surface of the lower shell 114 curve upwardly, and in the preferred example the heights h₁, h₂ not the same. In a preferred example, the height h₁ is about 9.4 mm and h₂ is about 12.3 mm, and the heights h₁, h₂ may range from about 9 mm to about 13 mm but are not limited to these dimensions.

FIG. 13 is a diagram illustrating a side elevation view of the example of the applicator 110 having the upper shell 112 and the lower shell 114 in an open configuration. FIG. 14 is a diagram illustrating a side perspective view of the example of the applicator 110 having the upper shell 112 and the lower shell 114 in an open configuration. Referring to FIGS. 13 and 14, the upper shell 112 and the lower shell 114 form an opening 117 for receiving a user's eyelashes when in an open configuration. As described above, the upper shell 112 and the lower shell 114 separate and are opened when the first arm 120 and the second arm 130 are moved away from each other. Accordingly, a user may adjust the size of the opening 117 by moving the first arm 120 and the second arm 130 with respect to one another.

FIG. 15 is a diagram illustrating a perspective view of the upper shell 112 of the applicator. Referring now to FIGS. 13 and 15, the upper shell 112 includes three points P1, P2, P3 at its bottom bending edge. The midpoint P2 is equidistant from the endpoints P1, P3. As shown in FIG. 13, the vertical distance d from one endpoint P3 to the midpoint P2 is approximately 4.5 mm and in a preferred example may range from approximately 4 mm to 5 mm. The angle γ formed by a line going through one endpoint P3 to the midpoint P2 and a line that is parallel with the extension the upper arm receiving member 112a, is approximately 40 degrees and in a preferred example may range from approximately 35 degrees to approximately 45 degrees. Referring to FIG. 15, in a preferred example, a circle that goes through the endpoints P1, P3 and the midpoint P2 has a radius of approximately 36 mm to 38 mm and preferably ranges from 35 mm to 40 mm. In a preferred example, a straight line from one endpoint P1 to the other endpoint P3 is approximately 29.00 mm or greater.

FIG. 16 is a diagram illustrating a common shape of an eyelid and eyelashes of a user of the eyelash curler. This diagram illustrates the most common shape which the eyelash curler 100, specifically the bottom bending edge of the upper shell 112 of the eyelash curler 100, aims to emulate. The vertical distance a shown in FIG. 16 corresponds to the distance d discussed above in reference to FIG. 13, and the distance b corresponds to the distance from one endpoint P1 to the other endpoint P3 discussed above in reference to FIG. 13. Accordingly, the shape of the bottom bending edge of the upper shell 112 is as similar as possible to the common eyelid shape so that the bending edge of the upper shell 112 may bend the eyelash as close to the root of each hair of the eyelash as possible. In an aspect, this provides an advantageous, more effective, and longer lasting curling shape to the eyelash as a result of being bent at the root, or as close to the eyelid as possible.

In an example, a method of using the eyelash curler 100 includes separating the upper shell 112 from the lower shell 114 using a first arm 120 and a second arm 130, inserting a user's eyelashes in an opening 117 formed by the upper shell 112 from the lower shell 114, closing the upper shell 112 from the lower shell 114 using the first arm 120 and the second arm 130, applying a pressure and a curvature to a user's eyelashes, and releasing the user's eyelashes by again separating the upper shell 112 from the lower shell 114 using the first arm 120 and the second arm 130.

In an aspect, it should appreciated that advantages of the eyelash curler 100 include providing a cage-free and long-extending eyelash curving surface. Specifically, the applicator 110 provides the most ideal shape and surface for the most effective curvature of a user's eyelashes. Other advantages include providing a product that is easy to use and configured to apply a curvature to a user's eyelashes quickly. Further, the eyelash curler 100 is portable, graspable by a user using a single hand, and is easy to carry. It should be appreciated by those skilled in the art that the advantages of the eyelash curler 100 are not limited to those described herein and are merely examples of the advantages of the invention.

It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that the invention disclosed herein is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.

Claims

1. An apparatus adapted to curl a user's eyelashes, comprising:

a first arm having a first end and a second end;

a second arm having a first end and a second end, the second arm joined to the first arm; and

an applicator comprising: an upper shell that is attached to the first end of the first arm; and a lower shell that is attached to the first end of the second arm,

wherein a surface of the upper shell is configured to face the user's eyelashes and has a concave curve that extends approximately 90 degrees or greater from one side to another side.

2. The apparatus of claim 1, wherein a surface of the lower shell is configured to face the user's eyelashes and has a concave curve that extends approximately 101 degrees or greater from one side to another side.

3. The apparatus of claim 1, further comprising a spring element attaching the first arm to the second arm at a position that is adjacent to the second end of the first arm and the second end of the second arm.

4. The apparatus of claim 1, further comprising a first handle attached to the second end of the first arm and a second handle attached to the second end of the second arm.

5. The apparatus of claim 4, wherein, in response to the first handle and the second handle being pressed together, the upper shell of the applicator and the lower shell of the applicator are separated.

6. The apparatus of claim 2, wherein the first arm comprises a left arm and a right arm that are in contact with one another and diverge at an intersection of the first arm with the second arm, the left arm connecting to the one side of the upper shell and the right arm connecting to the another side of the upper shell.

7. The apparatus of claim 6, wherein the second arm comprises a left arm and a right arm that are in contact with one another and diverge at the intersection of the first arm with the second arm, the left arm connecting to the one side of the lower shell and the right arm connecting to the another side of the lower shell.

8. The apparatus of claim 1, wherein the first end of the first arm intersects the upper shell at an approximately 90 degree angle.

9. The apparatus of claim 1, wherein the first end of the second arm intersects the lower shell at an acute angle.

10. The apparatus of claim 7, wherein the left arm and the right arm of the first arm are parallel to the left arm and the right arm of the second arm.

11. The apparatus of claim 1, wherein a first height of the upper shell at the one side is the same as a second height of the upper shell at the another side, and the first height and the second height are different from a third height at a middle of the upper shell.

12. The apparatus of claim 1, wherein a radius of curvature of the upper shell is approximately 20.6 mm.

13. An apparatus adapted to curl a user's eyelashes, comprising:

a first arm having a first end and a second end;

a second arm having a first end and a second end, the second arm joined to the first arm; and

an applicator comprising: an upper shell that is attached to the first end of the first arm; and a lower shell that is attached to the first end of the second arm,

wherein a surface of the lower shell is configured to face the user's eyelashes and has a concave curve that extends approximately 101 degrees or greater from one side to another side.

14. The apparatus of claim 13, wherein a surface of the upper shell is configured to face the user's eyelashes and has a concave curve that extends approximately 90 degrees or greater from one side to another side.

15. The apparatus of claim 13, further comprising a spring element attaching the first arm to the second arm at a position that is adjacent to the second end of the first arm and the second end of the second arm.

16. The apparatus of claim 13, further comprising a first handle attached to the second end of the first arm and a second handle attached to the second end of the second arm.

17. The apparatus of claim 16, wherein, in response to the first handle and the second handle being pressed together, the upper shell of the applicator and the lower shell of the applicator are separated.

18. The apparatus of claim 14, wherein the second arm comprises a left arm and a right arm that are in contact with one another and diverge at an intersection of the first arm with the second arm, the left arm connecting to the one side of the lower shell and the right arm connecting to the another side of the lower shell.

19. The apparatus of claim 18, wherein the first arm comprises a left arm and a right arm that are in contact with one another and diverge at the intersection of the first arm with the second arm, the left arm connecting to the one side of the upper shell and the right arm connecting to the another side of the upper shell.

20. The apparatus of claim 13, wherein the first end of the first arm intersects the upper shell at an approximately 90 degree angle.

21. The apparatus of claim 13, wherein the first end of the second arm intersects the lower shell at an acute angle.

22. The apparatus of claim 19, wherein the left arm and the right arm of the first arm are parallel to the left arm and the right arm of the second arm.

23. The apparatus of claim 13, wherein a first height of the lower shell at the one side is the same as a second height of the lower shell at the another side, and the first height and the second height are different from a third height at a middle of the lower shell.

24. The apparatus of claim 13, wherein a radius of curvature of the lower shell is approximately 20 mm.

25. An apparatus adapted to curl a user's eyelashes, comprising:

a first arm having a first end and a second end;

a second arm having a first end and a second end, the second arm joined to the first arm; and

an applicator comprising: an upper shell that is attached to the first end of the first arm; and a lower shell that is attached to the first end of the second arm,

wherein an edge of the upper shell comprises a first endpoint, a second endpoint, and a midpoint, and a line extending through the first endpoint and the midpoint forms an acute angle with a line that is parallel to an extension of the first end of the first arm.

26. The apparatus of claim 25, wherein the acute angle is approximately 40 degrees.

27. The apparatus of claim 25, wherein a distance from the first endpoint to the second endpoint is approximately 29 mm.

28. The apparatus of claim 25, wherein a phantom circle extending through the first end point, the midpoint, and the second endpoint has a radius ranging from approximately 36 mm to approximately 38 mm.

29. The apparatus of claim 25, wherein a distance from the first endpoint or the second endpoint to the midpoint is approximately 4.5 mm.