1. Field of the Invention
The present invention is directed generally to fabricating brushes and more particularly to devices and methods of installing bristles in brushes.
2. Description of the Related Art
Generally, a brush includes tufts each of which is formed from a plurality of bristles. A bristle is a single strand or filament having two ends and middle portion disposed between the two ends. The bristles that form a single tuft are typically arranged longitudinally adjacent to one another into a grouping of substantially parallel bristles.
Brushes have a broad range of uses from household cleaning to dental hygiene. The materials used to construct brushes are as varied as their uses. In particular, the materials used to construct bristles very widely. However, most bristle materials share a couple of common characteristics. First, they are generally stiff and capable of standing upright without lateral support. Second, bristles generally tolerate a great deal of bending.
Bending deforms the bristle material. Deformation can be either plastic or elastic. If the deformation is elastic, the material will return to its original shape after the stress is removed. On the other hand, if the deformation is plastic, the bristle material will not return to its original shape after the stress is removed. In other words, plastic deformation permanently alters the shape of the bristle material. Plastic deformation occurs when the stress applied to the bristle material exceeds the yield strength of the material. If sufficient stress is applied, materials may fail or fracture.
Bending a bristle causes a portion of the bristle to stretch and a portion diametrically opposed to the stretched portion to compress. Strain is a measure of the amount of deformation experienced by the bristle. With respect to the stretched portion, the amount of strain experienced by the material may be determined by dividing the amount the bristle has stretched by the original length of the bristle. If the strain is large enough, the material will experience plastic deformation. If the strain is too great, the material may fracture. If the fracture is large enough, the bristle may break into two separate segments.
Bristles are frequently constructed from materials such as nylon, straw, natural hair, and metal wire that tolerate a great deal of bending. The bendibility of most bristle materials facilitates the manufacture of the brush. Referring to
A staple 40 is used to fasten the bent portion 16 of the bristle grouping 12 to a body or head 42 of the brush. Frequently, the bent portion 16 of the bristle grouping 12 and staple 40 adjacent thereto are disposed within a single bristle aperture 50 in the head 42 of the brush. The bristle aperture 50 in the head 42 of the brush is generally cylindrically shaped and has a constant diameter along its depth. Opposite ends of the bristle grouping 12 protrude from the single bristle aperture 50 and form a single tuft 10. Generally, the diameter of the aperture 50 is approximately equal to or slightly larger than the diameter of the tuft 10 protruding therefrom. The narrowness of the bristle aperture 50 generally maintains a small radius of curvature in the bent portion 16 of each bristle.
Many materials that exhibit excellent qualities such as shape memory alloy, super elastic memory wire, and nitinol wire are difficult to fabricate into brushes because they cannot tolerate the strain involved in traditional methods of manufacture. As described in U.S. Pat. No. 6,442,785 issued to Robinson incorporated herein by reference, shape memory alloy is an excellent material for making brushes because the material is extremely durable and hydrophobic in nature, which renders it more hygienic. Super elastic memory wire has a composition substantially similar to shape memory alloy; however, super elastic memory wire exhibits somewhat different properties. Specifically, super elastic memory wire is not temperature sensitive. In other words, the temperature of super elastic memory wire need not be increased to produce the shape memory characteristics. Consequently, it may be desirable to use super elastic memory wire to construct bristles for brushes.
However, bristles formed from either super elastic memory wire or shape memory alloy cannot undergo strain exceeding about 8% without experiencing plastic or permanent deformation. This limitation is a particular problem with respect to bending where the tuft exits the bristle aperture. If a laterally directed force is applied to a tuft, such as occurs when the brush is used to clean or scrub a surface, the tuft bends away from the direction of movement of the brush and toward the surface of the brush head. Because the tuft is anchored by its base to the brush head, any lateral (shear) forces applied to the tuft will bend the tuft in an unconstrained manner toward the surface of the brush head. This bending is unrestricted by anything other than the tolerance of the brush material to bending. Under certain circumstances, the forces applied exceed the 8% strain tolerable by super elastic memory wire and shape memory. Therefore, the bristles within the tuft may kink or break near the location of the bend. Consequently, dental brushes with super elastic memory wire or shaped memory alloy bristles cannot be manufactured using traditional brush making methods described above.
Therefore, a need exists for methods and devices related to constructing brushes with bristles that cannot repeatedly tolerate more than a small amount of strain. A need also exists for a method of constructing a brush using bristles constructed from super elastic memory wire, shape memory alloy, nitinol wire, and the like. The present application provides these and other advantages as will be apparent from the following detailed description and accompanying figures.
Aspects of the present invention include a brush and bristle assembly therefor.
As may best be viewed in
In contrast to the prior art cylindrically shaped bristle aperture 50 depicted in
The sidewall 112 has a first portion 120 and a second portion 130. The first portion 120 is inside the brush head 102 and located between the second portion 130 and the bottom surface 114 of the aperture 110. The first portion 120 may have a lower portion 132 adjoining the bottom surface 114 of the aperture 110. However, this is not a requirement. Alternatively, the first portion 120 may be spaced from the bottom surface 114. Optionally, the lower portion 132 may be inwardly radiused, beveled, or otherwise relieved. In embodiments in which the lower portion 132 is radiused, the lower portion 132 of the first portion 120 has a depth “D1.” By way of a non-limiting example, when the brush 100 is configured for use as a dental brush, the depth “D1” of the lower portion 132 of the first portion 120 may be about 0.020 inches to about 0.040 inches. In particular embodiments, the depth “D1” of the lower portion 132 of the first portion 120 is about 0.030 inches.
The second portion 130 is inside the brush head 102 and located between the first portion 120 and the surface 106 from which the bristles 118 protrude. Thus, to form one of the tufts 119A and 119B, the bristles 118 are inserted into one of the apertures 110, and are anchored at or near the bottom surface 114 of the aperture 110. In the embodiment depicted in the figures, the first portion 120 is immediately adjacent to the second portion 130. However, this is not a requirement. The first portion 120 of the sidewall 112 defines a first portion 140 of the bristle aperture 110 and the second portion 130 of the sidewall 112 defines a second portion 142 of the bristle aperture 110. A portion of the bristles 118 of each of the tufts 119A and 119B pass through both the first portion 140 and the second portion 142 of the bristle aperture 110. The lower portion 132 is sized to receive at least a portion of the bristles 118 along a length thereof that is bent to form the tufts 119A and 119B.
Excluding the depth “D1” of the lower portion 132, the first portion 120 of the sidewall 112 and the first portion 140 of the bristle aperture 110 defined thereby have a depth “D2.” The second portion 130 of the sidewall 112 and the second portion 142 of the bristle aperture 110 defined thereby have a depth “D3.” Thus, a total depth of the aperture 110 is defined as a sum of the depth “D1,” the depth “D2,” and the depth “D3.” A ratio of the depth “D2” to the total depth of the aperture 110 may range from about 5% to about 40%.
By way of a non-limiting example, when the brush 100 is configured for use as a dental brush, the depth “D2” of the first portion 120 of the sidewall 112 may be about 0.025 inches to about 0.045 inches. In particular embodiments, the depth “D2” of the first portion 120 of the sidewall 112 is about 0.035 inches. By way of a non-limiting example, when the brush 100 is configured for use as a dental brush, the depth “D3” of the second portion 130 of the sidewall 112 may be about 0.10 inches to about 0.12 inches. In particular embodiments, the depth “D3” of the second portion 130 of the sidewall 112 is about 0.11 inches. Using the values above, the total depth of the bristle aperture 110 may range from about 0.127 inches to about 0.169 inches. In particular embodiments, the total depth of the bristle aperture 110 is about 0.143 inches.
The first portion 120 of the sidewall 112 extends toward the second portion 130 from the bottom surface 114 of the aperture 110. The first portion 140 of the bristle aperture 110 defined by the first portion 120 of the sidewall 112 has a substantially constant cross-sectional area. In other words, portions of the sidewall 112 opposite one another are substantially parallel, extending toward the second portion 130 in substantially the same direction. Thus, the first portion 140 of the bristle aperture 110 may have a cylindrical shape with a cross-sectional shape that is circular, elliptic, parabolic, hyperbolic, and the like. However, this is not a requirement. For example, the bristle aperture 110 may have a cross-sectional shape that is triangular, square, rectangular, octagonal, hexagonal, or other non-geometrical shape. However, it may be desirable to avoid cross-sectional shapes that include sharp corners.
Within the first portion 140 of the bristle aperture 110, the substantially constant cross-sectional area defined by the first portion 120 of the sidewall 112 guides the bristles 118 disposed inside the aperture 110 toward the surface 106. This constant cross-sectional area helps maintain the bristles 118 in an ordered bundle (or tuft) in which the bristles 118 extend outwardly toward the surface 106 in substantially the same first direction (i.e., the direction in which the sidewall 112 extends toward the second portion 130 from the bottom surface 114), identified by arrow “A” in
The second portion 130 of the sidewall 112 extends toward the surface 106 from the first portion 120 of the sidewall 112. The second portion 142 of the bristle aperture 110 defined by the second portion 130 of the sidewall 112 has a cross-sectional area that increases from the first portion 120 to the surface 106. The increasing cross-sectional area provides a deflection area 134 defined between the second portion 130 of the sidewall 112 and the bristles 118. In the illustrated embodiment, the deflection area 134 has a central portion 136 with the bristles 118 oriented within the central portion 136 of the deflection area 134. The first portion 120 of the sidewall 112 directs the bristles 118 into the central portion 136 of the deflection area 134.
In the embodiment illustrated, the cross-sectional area increases constantly but non-uniformly from the first portion 120 to the surface 106. In other words, the second portion 130 of the sidewall 112 extends outwardly as it extends toward the surface 106. The second portion 130 of the sidewall 112 is smooth and outwardly curved as it extends toward the surface 106. Thus, the second portion 142 of the bristle aperture 110 may have a tapered or flared shape, a conical shape, a funnel shape, a trumpet shape, a bell shape, and the like. However, this is not a requirement. Alternatively, the second portion 142 of the sidewall 112 may have one or more portions (not shown) that have cross-sectional areas that remain constant or decrease provided the deflection area 134 is present between the second portion 130 of the sidewall 112 and the bristles 118.
Referring to
By way of a non-limiting example, the second portion 142 may have a cross-sectional shape that is circular, elliptic, partially parabolic, partially hyperbolic, and the like. However, this is not a requirement. For example, the bristle aperture 110 may have a cross-sectional shape that is triangular, square, rectangular, octagonal, hexagonal, and the like. However, it may be desirable to avoid cross-sectional shapes that include sharp corners.
An outer portion 150 of the second portion 130 of the sidewall 112 intersects the surface 106 of the brush head 102 and forms a rounded shoulder. The smooth outwardly curving outer portion 150 may be outwardly radiused, beveled, or otherwise relieved. An innermost portion 152 of the outer portion 150 of the second portion 130 of the sidewall 112 has the smallest cross-sectional area of the outer portion 150.
Within the second portion 142 of the bristle aperture 110, the increasing cross-sectional area defined by the second portion 130 of the sidewall 112 allows the bristles 118 disposed inside the aperture 110 to spread apart somewhat as they approach the surface 106 of the brush head 102. The increasing cross-sectional area defined by the second portion 130 of the sidewall 112 also allows the bristles 118 disposed inside the aperture 110 to bend and flex during use before contacting the sidewall 112. As the tufts 119A and 119B are moved along a surface to be cleaned or otherwise engaged by the tufts, they may sway or otherwise deflect within the deflection area 134 of their respective bristle apertures 110. Inside the deflection area 134 of the bristle aperture 110 there are no surfaces about which the bristles 118 may be bent.
However, the second portion 130 of the sidewall 112 may provide a surface about which the bristles 118 may be bent if the tufts 119A and 119B are pressed by a sufficient amount of laterally directed force into contact with the second portion 130 of the sidewall 112. The shape of the second portion 130 of the sidewall 112 may be determined at least in part by the bending tolerance of the bristles 118. For example, the second portion 130 of the sidewall 112 may be contoured or otherwise configured to provide a surface against which the bristles 118 may be pressed having a large enough radius of curvature to prevent the bristles from failing, kinking, or otherwise deforming in an undesirable manner when pressed against the second portion 130 of the sidewall 112. In other words, the second portion 130 of the sidewall 112 limits the bend radius of the bristles 118 and provides for a smooth bend curvature of the bristles along the second portion 130 of the sidewall 112 when bent into engagement therewith. Thus, the second portion 130 of the sidewall 112 induces a bend radius in the bristles 118 that is greater than their minimum bend radius preventing the bristles from being damaged by laterally directed forces applied to the bristles.
As is apparent to those of ordinary skill in the art, after the tufts 119A and 119B contact the second portion 130 of the sidewall 112, the application of additional laterally directed force may bend a portion of the tufts 119A and 119B outside the bristle aperture 110 (not constrained by the second portion 130 of the sidewall 112) toward the surface 106. Thus, during use, a portion of the tufts 119A and 119B inside the deflection area 134 of the bristle aperture 110 may bend without undesirable breakage or deformation before contacting the second portion 130 of the sidewall 112. The second portion 130, which includes the outer portion 150, helps maintain a minimum bend radius in the bristles 118 to inhibit damage to the tufts 119A and 119B.
Optionally, and in the embodiment illustrated, a pair of opposing longitudinal cutouts or channels 160 and 162 may be formed in the sidewall 112. As illustrated, the channels 160 and 162 may also extend into the lower portion 132 of the first portion 120 of the bristle aperture 110. The channels 160 and 162 are configured to receive the edge portions of a staple 170 and guide the staple into the bristle aperture 110 toward the bottom surface 114. In the embodiment depicted, the channels 160 and 162 are tapered and narrow as they approach the bottom surface 114. In other words, the cross-sectional area of the channels 160 and 162 decreases as the channels extend from the surface 106 toward the bottom surface 114. In this manner, the staple 170 may pass readily through portions of the channels 160 and 162 adjacent the surface 106 but become wedged and held by friction in portions of the channels 160 and 162 spaced from the surface 106. During insertion into the channels 160 and 162, the staple 172 may cut into a portion of the sidewalls of one or both of the channels and become embedded in the brush head 102.
During assembly of the brush 100, a middle portion 176 of the bristles 118 is forced into the bristle aperture 110 using any method known in the art. By way of a non-limiting example, the staple 170 may be used to force the middle portion 176 of the bristles 118 into the bristle aperture 110 using any method known in the art. Once inside the bristle aperture 110, the bristles 118 are bent by the sidewall 112 to form a bent portion 178 flanked by a first end portion 180 and a second end portion 182. The first end portion 180 extends outwardly and exits the bristle aperture 110 through a first portion 184 thereof. The second end portion 182 of the bent bristles 118 extends outwardly and exits the bristle aperture 110 through a second portion 186 thereof.
Alternatively, the channels 160 and 162 may be utilized by a bristle insertion tool (not shown) to insert the bristles 118 into the bristle apertures 110. After or before insertion, an adhesive or epoxy may be inserted into the bristle aperture 110 to anchor the bristles 118 therein.
The first portion 140 of the bristle aperture 110 has a length “L1” and a width “W1.” At its intersection with the surface 106, the second portion 142 of the bristle aperture 110 has a length “L2” and a width “W2.” Further, the inner most portion 152 of the outer portion 150 of the second portion 130 of the sidewall 112 defines a cross-sectional shape having a length “L3” and a width “W3.” When the brush 100 is configured for use as a dental brush, the width “W2” may be at least two to three times greater than width “W1.”
By way of a non-limiting example, the length “L1” of the first portion 140 of the bristle aperture 110 may be about 0.030 inches to about 0.050 inches. In particular embodiments, the length “L1” is about 0.040 inches. By way of a non-limiting example, the width “W1” of the first portion 140 of the bristle aperture 110 may be about 0.016 inches to about 0.03 inches. In particular embodiments, the width “W1” is about 0.023 inches.
At its intersection with the surface 106, the length “L2” of the second portion 142 of the bristle aperture 110 may be about 0.080 inches to about 1.000 inches. In particular embodiments, the length “L2” is about 0.090 inches. By way of a non-limiting example, the width “W2” of the second portion 142 of the bristle aperture 110 may be about 0.08 inches to about 0.10 inches. In particular embodiments, the width “W2” is about 0.09 inches.
The length “L3” of the innermost portion of the outer portion 150 of the second portion 130 of the sidewall 112 may be about 0.045 inches to about 0.065 inches. In particular embodiments, the length “L3” is about 0.055 inches. By way of a non-limiting example, the width “W3” of the inner most portion of the outer portion 150 may be about 0.060 inches to about 0.090 inches. In particular embodiments, the width “W3” is about 0.075 inches.
The bristles 118 may be constructed using any suitable material, including materials resistant to bending such as super elastic memory wire, shape memory alloy, nitinol wire, and the like. The number of bristles 118 used to construct the tufts 119A and 119B may vary based on application. By way of a non-limiting example, between 8 and 24 bristles may be used. In the embodiment depicted, 16 bristles have been used to create each of the tufts 119A and 119B by folding the bristles back against themselves. Thus, each of the tufts 119A and 119B has 32 bristles extending outwardly from the bristle aperture 110.
The brush head 102 and the handle 104 may be constructed using any suitable method and material known in the art, including plastic. For example, the handle 104 may be integrally formed with the adjacent generally solid brush head 102. In an alternate embodiment, the handle 104 may be removably attached to the brush head 102. One of ordinary skill of the art will appreciate that many methods for constructing brushes with handles and brush heads exist in the prior art and the manner of attachment or configuration of the handle 104 relative to the brush head 102 does not limit the invention. While the brush 100 is depicted as a dental brush, it is appreciated by those of ordinary skill in the art that through application of ordinary skill to the present teachings many other types of brushes such as hair brushes, cleaning brushes, and the like may be constructed and that such brushes are within the scope of the present teachings.
Returning to
In alternate embodiments (not depicted), the staple 170 may be omitted. Instead, any alternate fasteners known in the art may be used to non-removably fasten or anchor the bristles 118 within the bristle aperture 110. Alternatively, adhesives, such as an epoxy, may be used to anchor the bristles 118 inside the bristle apertures 110.
Referring to
Optionally, the bristles 118 may be coated with nylon, an elastomeric material (such as low durometer silicone), and the like. For example, bristles constructed from shape memory alloy, super elastic memory wire, nitinol wire, and the like may be coated with nylon, an elastomeric material, and the like and used to construct the brush 100.
The foregoing described embodiments depict different components contained within, or connected with, different other components. It is to be understood that such depicted architectures are merely exemplary, and that in fact many other architectures can be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively “associated” such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality can be seen as “associated with” each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated can also be viewed as being “operably connected,” or “operably coupled,” to each other to achieve the desired functionality.
While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that, based upon the teachings herein, changes and modifications may be made without departing from this invention and its broader aspects and, therefore, the appended claims are to encompass within their scope all such changes and modifications as are within the true spirit and scope of this invention. Furthermore, it is to be understood that the invention is solely defined by the appended claims. It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations).
Accordingly, the invention is not limited except as by the appended claims.
Number | Date | Country | |
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Parent | 11556126 | Nov 2006 | US |
Child | 12234206 | US |