Abstract:
A bristle structure including at least two stem wires spirally wound together to form a longitudinally extending core of the bristle structure and a plurality of bristles extending outwardly from the longitudinally extending core. Each of the bristles has a first end and an opposed second end, and each of the bristles is clamped between the stem wires such that the second end of each bristle extends a greater distance from the longitudinally extending core than the first end of the each bristle.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a division of U.S. application Ser. No. 11/509,916, filed Aug. 25, 2006, the entirety of which is incorporated herein by reference 
     
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to a twisted-in-wire brush having an offset helical bristle pattern, and a method of making the brush. 
       BACKGROUND OF THE INVENTION 
       [0003]    Twisted-in-wire (TIW) brushes are well known in the art. These brushes mechanically retain bristles between two or four stem wires. Traditionally, the bristles are centered lengthwise between the stem wires, which are then twisted to lock the bristles in place and to create a generally cylindrical brush having an outside diameter equal to the length of the bristles used. 
         [0004]    As shown in  FIGS. 6 and 7 , a typical TIW brush  10  of the prior art is made by first centering individual bristles  20  between two stem wires  30 . The individual bristles all have substantially the same length varying only by normal manufacturing tolerances. Stem wires  30  are then twisted about an axis  40  centered between the two stem wires  30  and centered along a longitudinal axis  50  of the individual bristle  20 . The twisting results in a pinching force between the two stem wires that holds the bristles  20  in position. 
         [0005]    The resulting brush  10  has bristles  20  spirally revolving to form two helixes extending centered along the axis  40 . Outer ends of the bristles  20  revolve to form an outside diameter  60  which is equal to the length of the bristles  20 . 
         [0006]    The stem wires  30  can extend beyond the brush portion containing bristles  20 . This extension portion can be covered with a handle  70 , as shown in  FIG. 6 . The handle  70  can be attached to extending portions (not shown) of the stem wires  30 , which do not contain bristles. 
         [0007]    As shown in  FIGS. 6 and 7  typical TIW brushes have a consistent outer surface where all of the ends of the bristles terminate along a uniform outside diameter of the brush. While these bristles may bend during use to take on the shape of a work surface, the bristles themselves terminate at the same diameter. 
         [0008]    The uniform outer diameter functions well when the brush is used against surfaces that have a correspondingly continuous or uniform surface (e.g., the inside of a round pipe or tube, or the flat surface of a metal plate). Problems arise, however, when such a brush is tasked with performing a cleaning function on an irregular surface. One such problem begins when a user attempts to force a typical TIW brush into recess portions of a surface such as in corners or along a grate, which often collect dirt and grime to be removed. For the typical TIW brush to reach these locations, many of the bristles must be bent or otherwise deformed to allow some of the bristles to reach the recessed surface. If such bristles are metallic in nature, the bristles may become permanently deformed, thus effectively ruining those portions of the brush for future use. 
         [0009]    Another problem with traditional TIW brushes is their lack of space available to accept larger or bulky residue. Residue such as grease chunks, soil, or lint must be forced through the outside diameter of the TIW brush and then be lodged near the stem wire intermixed between the individual bristles. While this may seem like an advantage, any such residue is very difficult to remove allowing the TIW brush to be reused in the future. 
         [0010]    Another disadvantage of traditional TIW brushes becomes apparent when the brushes are made having a relatively large outside diameter. Material costs for all metals and plastics have skyrocketed from historic levels. Traditional TIW brushes would require the bristles in such a brush having a large outside diameter to be the same length as the diameter of the brush itself. The cost of the bristles may then become a significant factor requiring a consumer to purchase a brush which is shorter than required or smaller in outside diameter than required. Either concession may reduce the cleaning effect desired by the consumer. 
         [0011]    To avoid some of these pitfalls normally seen in traditional TIW brushes, designers have resorted to trimming selective bristles of a traditional TIW brush to form a contoured design. For example, TIW brushes used in the mascara industry often have bristles trimmed in a helical or arcuate shape to better allow the transfer of mascara from the TIW brush to a user&#39;s eyelash. The economy of such trimming is, however, questionable. The trimming process adds an additional, time consuming step to the process of manufacturing a TIW brush, and the raw materials that are trimmed from the brush during manufacture are typically wasted. While it is possible that the trimmed bristle material may be recycled, that material would need to be completely remanufactured before the material could be used again as a bristle. 
         [0012]    For at least the reasons explained above, it is clear that a new TIW brush and method of manufacture is required to solve the above problems, while, at the same time decreasing the amount of waste created during the manufacturing process. 
       SUMMARY OF THE INVENTION 
       [0013]    It is an object of the present invention to overcome the problems with prior art brush designs, as discussed above. In accordance with one embodiment of the present invention, a bristle structure is provided that includes at least two stem wires spirally wound together to form a longitudinally extending core of the bristle structure. A plurality of bristles extend outwardly from the longitudinally extending core, and each of the bristles has a first end and opposed second end. The bristles are clamped between the stem wires such that the second end of each bristle extends a greater distance from the longitudinally extending core than the first end of each bristle. 
         [0014]    The resultant bristle structure includes two helical patterns extending along the length of the brush, which provides a contoured outer brush surface that is more effective at cleaning irregular work surfaces. 
         [0015]    In accordance with a second embodiment of the present invention, a bristle brush is provided that includes at least two stem wires spirally wound together to form a longitudinally extending core having a first end and an opposed second end. The bristle brush further comprises first and second support arms respectively extending from the first and second ends of the longitudinally extending core, and a plurality of bristles extending outward from the longitudinally extending core. Each of the bristles has a first end and an opposed second end, and is clamped between the stem wires such that the second end of each bristle extends a greater distance from the longitudinally extending core than the first end of the bristle. A handle is coupled to at least one of the first and second support arms. 
         [0016]    Preferably, the first and second support arms are integral extensions of the stem wires that form the longitudinally extending core. According to one embodiment of the present invention, the first and second support arms extend along the longitudinally extending core, and a handle is coupled to only one of the support arms such that the handle also extends in substantially the same direction as the longitudinally extending core. In accordance with another embodiment, at least a portion of each of the first and second support arms extend in a direction substantially perpendicular to the longitudinally extending core, and a handle is coupled to both of the support arms such that the handle also extends in a direction substantially perpendicular to the longitudinally extending core. 
         [0017]    In accordance with another embodiment of the present invention, a method of manufacturing a bristle structure includes the steps of positioning a plurality of bristles between at least two stem wires such that a first end of each bristle extends outward from the stem wires a first distance and a second end of each bristle extends outward from the stem wires a second distance greater than the first distance. The method further includes the step of spirally winding the stem wires together to form a longitudinally extending core of the bristle structure and to clamp the bristles between the stem wires. The first ends of the bristles collectively forming a first helical pattern extending along the longitudinally extending core and the second ends of the bristles collectively form a second helical pattern extending along the longitudinally extending core. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    For a fuller understanding of the nature and objects of the invention, reference should be made to the following detailed description of a preferred mode of practicing the invention, read in connection with the accompanying drawings in which: 
           [0019]      FIG. 1  is a top view of a twisted-in-wire brush made in accordance with one embodiment of the present invention; 
           [0020]      FIG. 2  is a partial sectional view of the twisted-in-wire brush shown in  FIG. 1 ; 
           [0021]      FIG. 3  is a top view of an intermediate manufacturing step according to an embodiment of the present invention; 
           [0022]      FIG. 4  is a side view of the intermediate manufacturing step depicted in  FIG. 3 ; 
           [0023]      FIG. 5  is a top view of a second embodiment of the present invention; 
           [0024]      FIG. 6  is a top view of a prior art twisted-in-wire brush; and 
           [0025]      FIG. 7  is a partial sectional view of the twisted-in-wire brush shown in  FIG. 6 . 
           [0026]      FIG. 8  is a perspective view of the second embodiment shown in  FIG. 5 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0027]      FIGS. 1 and 2  show a TIW brush in accordance with one embodiment according to the present invention. The size, shape, and number of bristles  120  in any given brush is a function of customer preference. The brush  100  shown in  FIG. 1  contains many relatively fine bristles  120  held between two stem wires  130 , which are shown in  FIG. 1  partially obscured by the bristles  120 . The location of the stem wires  130  can be seen covered with a cap  190  at one end and covered with a handle  170  at the other. 
         [0028]    For the sake of clarity,  FIG. 2  is provided as a section of the brush  100  taken through the brush area. Only two bristles are shown, but it should be understood that different numbers, size, and shapes of bristles can be used in accordance with the present invention. Bristles  120  are retained between the two stem wires  130  at a point along the center axis  140  of the completed brush. The bristles  120  are mounted such that one end of each bristle  120  extends further beyond the stem wires  130  than the other end. This arrangement allows the more distant ends of the bristle  120  to define a larger brush diameter  180 , and the ends of the bristles  120  closer to the stem wires  130  to define a smaller brush diameter  160 . 
         [0029]    The brush  100  takes on an auger-like appearance where the larger diameter  180  and the smaller diameter  160  helically extend along the length of the brush  100 . Debris and other residue can easily reside in the brush  100  between the smaller diameter  160  and the larger diameter  180  helixes. Furthermore, the bristles  120  forming the larger diameter helix  180  can more easily reach into surface discontinuities and around rises, such as ribs of a grate (e.g., BBQ grill). 
         [0030]    Referring now to  FIGS. 3 and 4 , the manufacturing process according to one embodiment of the present invention includes aligning the bristles  120  between the two stem wires  130  in a novel manner. Preferably, all of the bristles have substantially the same length. It should be noted, however, that the bristles will vary in length by normal manufacturing tolerances. The bristles  120  are arranged such that one end of each of the bristles  120  extends beyond the stem wire  130  a distance that corresponds to the larger diameter helix  180  of the finished brush  100 . The other end of each of the bristles  120  extending a shorter distance from the stem wires corresponds to the desired smaller diameter helix  160  of the finished brush. 
         [0031]    The process of aligning the bristles between the stem wires and subsequently twisting the stem wires can be accomplished through manual means. However, for the quantities and efficiency required with a larger scale production, an automatic machine can be selected. For example, a TIW brush  100  in accordance with the present invention can be made using a modified Borghi AB4 continuous cycle twisting machine. In the Borghi twisting machine, guides are typically arranged to center the bristles between two converging stem wires. The method of making a brush  100  in accordance with the present invention involves shifting the bristle guides to one side of their normal location so that the bristles  120  are no longer centered lengthwise between the two stem wires. It should be understood that other continuous cycle twisting machines can be used to create the brush  100  in accordance with the present invention. 
         [0032]    The larger outer diameter helix  180  can be easily determined based on the distance between the bristle guides (not shown in  FIGS. 3-4 ) on the twisting machine. For every unit of measure the bristle is moved to one side, the larger diameter helix  180  increases by twice that amount. Accordingly, the smaller diameter helix  160  is likewise decreased by the same amount that the larger diameter helix  180  is increased. Preferably, the bristles  120  are offset such that one end of each bristle  120  extends from the center axis  140  a distance that is 10% greater than the distance that the other end of bristle  120  extends from the center axis  140 . The longer ends of the bristles  120  collectively form the larger diameter helix  180  extending along the center axis  140 , and the shorter ends of the bristles  120  collectively form the smaller diameter helix  160  extending along the center axis  140 . 
         [0033]    It should be understood that the present invention can be made with various different characteristics relating to the desired brush type. For example, the bristles  120  can be made from any known bristle material such as plastic, carbon steel, stainless steel, brass, aluminum, etc. Additionally, the stem wires  130  can be made out of similar materials such as carbon steel, stainless steel, brass, aluminum, etc. The number of bristles can also be varied according to the desired function of the brush. For example, the embodiment disclosed in  FIG. 1  of the present application discloses the use of a large number of fine individual bristles allowing the brush to be used for smaller, lighter products. On the other hand, larger, more dispersed fibers, such as those shown in  FIGS. 3 and 4 , for example, can also be used. 
         [0034]    Stem wires  130  perform various functions. Stem wires  130  must be strong enough to generate sufficient grip between the two stem wires  130  to reliably retain the bristles  120 . Additionally, certain uses require that the brush  100  have sufficient bending and buckling strength to allow the brush to be held in various directions and pushed into locations to be cleaned. Aside from the strength requirements, the diameter of the wire is important as the diameter sets the pitch of the helix to be formed by setting the space held between the individual bristles or groups of bristles. As is well known in the art, more stem wires  130  can be utilized to nearly double the distance between the bristles and nearly double the length of one pitch of the helix. 
         [0035]    One application of the novel brush design according to the present invention is a grill cleaning brush, as shown in  FIG. 5 . The grill cleaning brush  200  includes low carbon soft steel stem wires  130  holding a plurality of fine brass bristles  120 . The individual bristles  120  are held within the stem wires  130  such that a double helix is created, one helix having a larger diameter, the other having a smaller diameter. Stem wires  130  extending beyond the bristles  120  are arranged and bent such that they come together and extend to be mounted within a handle  270 . The handle can be made out of plastic, wood, brass, etc. 
         [0036]      FIG. 8  shows the brush structure of  FIG. 5  being used to clean a barbeque grill.  FIG. 8  shows that the bristles  120  of the larger diameter helix  280  are able to extend through the grill  290  in such a way that sides of the grill rods  310  can be cleaned.  FIG. 8  also shows that bristles  120  of the smaller diameter helix  260  effectively clean top sides of the grill rods  310 . Accordingly, the grill cleaning brush  200  is able to clean more surfaces of the grill  290  than a typical grill brush. 
         [0037]    Another application is a lint brush for cleaning dryer vents, as shown in  FIG. 1 , the structure of which has already been described. 
         [0038]    While the present invention has been particularly shown and described with reference to the preferred mode as illustrated in the drawings, it will be understood by one skilled in the art that various changes may be effected therein without departing from the spirit and the scope of the invention as defined by the claims.