Abstract:
A tubular web element is made from a strip of fabric having opposing longitudinal edges. The strip is longitudinally twisted to define a hollow tube having between approximately 0.01-0.95 turns per inch. At least one helical gap is defined between the opposing longitudinal edges of the hollow tube. The opposing longitudinal edges have self-fused edge regions. The hollow tube has self-fused longitudinally-extending regions between its opposing longitudinal edges.

Description:
Pursuant to 35 U.S.C. §119, the benefit of priority from provisional application 61/790,758, with a filing date of Mar. 15, 2013, is claimed for this non-provisional application. 
    
    
     FIELD OF THE INVENTION 
     The invention relates generally to mops, and more particularly to a web element that is both twisted and tubular, and mop heads made from such web elements. 
     BACKGROUND OF THE INVENTION 
     A variety of wet and dry mop constructions are known in the art. Such constructions include those utilizing mop elements made from twisted natural or synthetic fiber or yarns as well as those made from planar web elements of woven or non-woven materials having involutions or twists formed along the length thereof. Regardless of their construction, a good mop strives to achieve the following goals:
         the ability to absorb or pick-up liquid and/or particulate accumulations on a floor surface,   the ability to release the absorbed or picked-up liquid and/or particulate when the mop is compressed,   the ability to be used effectively on a rough floor surface without tearing or generating lint during use,   the ability to withstand multiple launderings while maintaining structural integrity and its absorption, retention, and release properties, and   the ability to eliminate linting or shedding during general handling.       

     Current mop constructions can provide some, but not all, of these properties. For example, U.S. Pat. No. 4,995,133 teaches a mop made from planar web elements that can be processed to form involutions or twists along the length thereof to create capillaries that increase absorption and retention of liquid and/or particulates. The involutions/twists can be maintained by either overwrapping a helical strand about the web element or by applying adhesive along the web element. However, both of these approaches present problems. In the case of a helical overwrap, the overwrapping tension must be tightly controlled as the involutions/twists will not be maintained if the overwrap is too loose while the capillary effect of the involutions/twists will be inhibited/negated if the overwrap is too tight. In the case of adhesion bonding, points or areas of adhesion between web element surfaces define “catch points” for particulate matter in the mop element that can inhibit the capillary effect. Furthermore, upon laundering of such adhesion-bonded mop elements, the points of adhesion form stress points that can lead to tearing of the web elements adjacent to the bond region since the bond region is often stronger that the material being bonded. The resulting tears diminish the capillary effect and define new regions for lint to be released from the mop element during use thereof. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide a mop element for use in wet and dry mop applications. 
     Another object of the present invention is to provide a mop element having good absorption, retention, and release properties. 
     Still another object of the present invention is to provide a mop element that resists tearing and the generation of lint during use. 
     Yet another object of the present invention is to provide a mop element that retains its properties after being laundered and dried. 
     Other objects and advantages of the present invention will become more obvious hereinafter in the specification and drawings. 
     In accordance with the present invention, a tubular web element is made from a strip of fabric having opposing longitudinal edges. The strip is longitudinally twisted to define a hollow tube having between approximately 0.01 turns per inch to approximately 0.95 turns per inch along a length of the hollow tube. At least one helical gap is defined between the opposing longitudinal edges of the hollow tube. The opposing longitudinal edges have self-fused edge regions therealong. The hollow tube has self-fused longitudinally-extending regions between its opposing longitudinal edges. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other objects, features and advantages of the present invention will become apparent upon reference to the following description of the preferred embodiments and to the drawings, wherein corresponding reference characters indicate corresponding parts throughout the several views of the drawings and wherein: 
         FIG. 1  is a front view of a portion of a mop using a mop head constructed from mop elements in accordance with an embodiment of the present invention; 
         FIG. 2  is a plan view of a mop head constructed from a continuous length or multiple lengths of twisted and looped mop elements in accordance with an embodiment of the present invention; 
         FIG. 3  is a plan view of a strip of planar material used to form a web element in accordance with an embodiment of the present invention; 
         FIG. 4  is an enlarged view of a portion of an edge of the strip of planar material appearing in the dashed-line-circle region thereof illustrated in  FIG. 3 ; 
         FIG. 5A  is the enlarged view of the portion of an edge of the strip of planar material after the edge has undergone self-fusion at small areas thereof to thereby form fused fiber regions; 
         FIG. 5B  is the enlarged view of the portion of an edge of the strip of planar material after the edge has undergone extensive self-fusion to thereby form a fused bead; 
         FIG. 6  is a side view of the strip of planar material after it has been twisted and heated to form self-fused regions therealong in accordance with an embodiment of the present invention; 
         FIG. 7  is a plan view of the strip of planar material as it would appear if it were untwisted in order to illustrate the self-fused regions created through heat processing; 
         FIG. 8A  is a cross-sectional view of a crease/pleat formed along a web element during twist processing thereof; 
         FIG. 8B  is a cross-sectional view of the crease/pleat after it has undergone self-fusion to form a self-fused region along the twisted web element; 
         FIG. 9  is a side view of the twisted mop element of  FIG. 6  with netting disposed thereabout in accordance with another embodiment of the present invention; and 
         FIG. 10  is a side view of the strip of planar material after it has been twisted and heated to form self-fused regions therealong in accordance with another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, simultaneous reference will be made to  FIGS. 1 and 2  where a mop  10  for removing liquid and/or particulate accumulations on a floor surface uses a mop head  12  constructed from web elements  20  in accordance with an embodiment of the present invention. Mop  10  includes mop head  12  connected to a retention yoke  14  that includes a fitting  16  connected to a mop handle  18 . It is to be understood that the construction of the various parts used to support mop head  12  can be different from that shown without departing from the scope of the present invention. 
     Mop head  12  includes a plurality of web elements  20  that start as planar strips of material which are then twisted into a loose hollow tubular shape that is looped back onto itself at the mop head&#39;s distal ends  12 A and  12 B. That is, each twisted tubular web element  20  I mop head  12  has substantially adjacent and spaced-apart legs  20 L 1  and  20 L 2  terminating in a free end loop  28  at one of distal ends  12 A and  12 B. A backing member in the form of a head band  22  is wrapped about the central portions of the twisted and looped web elements  20  and connected thereto by stitching  24 . The twisted and looped elements  20  are gathered and connected to tail bands  26  by stitching thereby establishing free end loops  28  at distal ends  12 A and  12 B of mop head  12 . The position of tail band  26  relative to free end loops  28  can be adjusted to provide the desired length of free ends for the desired mopping application. Tail bands  26  also keep the twisted and looped web elements  20  spaced apart during mopping and during laundering to increase the mop&#39;s cleaning effectiveness and to allow the individual web elements  20  to be effectively cleaned during laundering. It is to be understood that a single length of twisted web element  20  can be looped back-and-forth to create mop head  12 , or numerous twisted and looped lengths of twisted web element  20  could be used to create mop head  12  without departing from the scope of the present invention. 
     Referring additionally now to  FIGS. 3-7 , details of a single web element  20  in accordance with the present invention will now be described. In  FIGS. 3-4 , web element  20  is illustrated in its pre-processed form. In general, the pre-processed form of web element  20  is a strip of material on the order of 0.25-2.0 inches in width (“W”) and a length (“L”) that can be on the order of 5-6 feet (if a mop head is to be made from individual lengths of web elements  20 ) to a couple of hundred feet (if a mop head is to be made from a continuous length of a single web element  20 ). 
     Suitable materials for web element  20  include a wide variety of woven and/or non-woven materials made from natural and/or synthetic components as well as combinations thereof. A number of such suitable materials are described in the afore-mentioned U.S. Pat. No. 4,995,133, the contents of which are hereby incorporated by reference. In general, the choice of material(s) for web element  20  should allow for self-fusing to occur at regions thereof when the web element is exposed to heat for a period of time as will be explained further below. The amount of heat and time required for such self-fusing will vary based on the melting or fusing point associated with the material(s) being used. It is to be understood that the material(s) used as well as the structure of the planar strip (e.g., single ply, multi-ply laminate, etc.) can be varied to suit the needs of a particular application without departing from the scope of the present invention. 
     Regardless of the type of material(s) used for web element  20 , opposing longitudinal edges  20 E thereof will be fibrous as clearly shown in the enlarged view thereof presented in  FIG. 4 . Fibrous edges  20 E can be due to the nature of the material(s) used and/or due to the way the strip was generated (e.g., a waste cut from an ancillary fabrication process using a larger bolt of the same material(s)). In general, fibrous edges  20 E are mechanically weak. However, if the material(s) used for web element  20  can experience self-fusing when exposed to heat (or some other fusing catalyst processing), the strength of the web element at fibrous edges  20 E can be improved. As used herein, the term “self-fusing” means that fibers in fibrous edges  20 E fuse to each other as will be explained further below. 
     In accordance with the present invention, “self-fusing” at fibrous edge  20 E can be achieved somewhat microscopically or locally at small groups of fibers at fibrous edge  20 E, or on a more macro level along some of all of fibrous edge  20 E. Accordingly,  FIG. 5A  illustrates the enlarged view of fibrous edge  20 E shown in  FIG. 4  where the fibrous edge has undergone small amounts of local fusing such that groups of adjacent fibers from fibrous edge  20 E are fused together (e.g., melted, heat set, etc.) to form small fused fiber regions indicated by the bold-line edge areas designated by reference numeral  20 EF. Depending on the material used, the type of fusing “catalyst”, and/or the length of time the material is exposed to a fusing “catalyst”, a greater amount of fusing can occur along fibrous edge  20 E. Accordingly,  FIG. 5B  illustrates the enlarged view shown in  FIG. 4  when the fibrous edge has undergone extensive self-fusing to thereby form a fused bead  20 F. Fused bead  20 F can be continuous or discontinuous along the length of the strip without departing from the scope of the present invention. It is to be understood that the self-fusing examples in  FIGS. 5A and 5B  depict approximate minimum ( FIG. 5A ) and maximum ( FIG. 5B ) levels of self-fusing, and that the term “self-fusing” as used herein is meant to include the range of self-fusing between the depicted minimum and maximum levels. It is further to be understood that self-fusing in the present invention is meant to include self-fused edges that combine different levels of self-fusing. 
     Regardless of the amount of self-fusion that takes place at fibrous edge  20 E, the resulting self-fused edge (or regions thereof) is mechanically stronger than without self-fusing. Additionally, the self-fusing permanently alters the fiber memory thereby allowing the creation and retention of new shapes. The present invention takes advantage of the fusibility of the web element&#39;s material(s) in order to construct a twisted and looped web element for use in a mop head. That is, the present invention&#39;s twisted mop element includes regions of self-fusing that improve the mop element&#39;s mechanical strength and function to retain the mop element&#39;s twist. A portion of a twisted web element  20  with fused regions therealong is illustrated in  FIG. 6 . For purposes of explanation only, an untwisted and flattened illustration of web element  20  with fused regions formed therealong is shown in  FIG. 7 . Web element  20  is twisted in a longitudinal fashion to define a tubular structure defining a tubular region  20 T. By way of example and for simplicity of illustration, web element  20  in  FIGS. 6 and 7  has fused bead regions  20 F. However, as explained above, the amount/degree of self-fusing that occurs can be different without departing from the scope of the present invention. 
     The amount of twist introduced in web element  20  is slight (i.e., between approximately 0.01 turns per inch and approximately 0.95 turns per inch) so that gentle helical gaps  20 G are formed along the length of twisted web element  20  as shown in  FIG. 6 . Gaps  20 G define an entryway to tubular region  20 T formed within twisted web element  20 . In general, the use of wider strips and/or dense materials will utilize less turns per inch than narrower and/or less dense material. In all cases, the turns per inch used should create helical gaps  20 G to allow liquid and/or particulate matter to be absorbed and retained within tubular region  20 T, and then released from tubular region  20 T when the web element is compressed (e.g., when a mop made from the twisted web elements is squeezed out). 
     In addition to the above-described gentle twist, twisted web element  20  will undergo some heat processing that forms self-fused beads  20 F (described above) as well as other self-fused regions  20 R along the length of twisted web element  20 . If such heat processing is performed while the web element is being twisted, self-fused regions  20 R will occur generally along the twisted length of twisted web element  20  as best illustrated in an untwisted and flattened drawing thereof presented in  FIG. 7 . Self-fused regions  20 R extend generally along the twisted length of twisted web element  20  because twist processing generally involves some tensioning of the web element along its length such that slight creases or pleats can be formed randomly therealong. These creases/pleats serve as the sites for the formation of self-fused regions  20 R by virtue of heat processing. A cross-section of a crease/pleat  20 C prior to the fusing thereof is illustrated in  FIG. 8A , and a cross-section of the crease/pleat after undergoing self-fusion to form self-fused region  20 R is illustrated in  FIG. 8B . Additionally or alternatively, such self-fused regions could be generated to define some orderly pattern without departing from the scope of the present invention. Neither fused beads  20 F nor fused regions  20 R impede gaps  20 G or tubular region  20 T. Accordingly, twisted web element  20  ( FIG. 6 ) can achieve uniform absorption, retention, and release properties all along its length. 
     Testing has shown that the inclusion of self-fused beads  20 F and self-fused regions  20 R set and retain the twisted tubular structure of twisted web element  20  illustrated in  FIG. 6 . That is, self-fused beads  20 F and self-fused regions  20 R permanently alter the mechanical memory of the material from its pre-processed planar strip form ( FIG. 3 ) to its post-processing twisted tubular structure ( FIG. 6 ). Further, it has also been found that the twisted tubular structure ( FIG. 6 ) is retained even after multiple uses and laundering. Thus, the properties and advantages achieved by twisted web element  20  ( FIG. 6 ) will last throughout the life of a mop constructed therefrom. Still further, the self-fusing along the edges of a web element (e.g., fused bead  20 F) and along the body of a twisted tubular web element (e.g., fused regions  20 R) add a texture to the surface of the twisted web element such that mops made therefrom will improve a user&#39;s ability to scrub a floor surface as the mop is swabbed thereover. 
     The above-described web element can be made more durable while maintaining the absorption, retention, and release attributes. For example,  FIG. 9  illustrates a twisted web element  20  (similar to that described above and shown in  FIG. 6 ) with a netting  30  disposed thereabout along the length thereof. Netting  30  can be made from a durable fiber to include man-made and natural polymers. Netting  30  provides circumferential support of twisted web element  20  without having to apply a tightly-controlled compression force thereto in order to stay in place. Accordingly, the integrity of gaps  20 G and tubular region  20 T are retained, while netting  30  can serve as a durable contact point for a rough floor surface and provide support for the web element structure throughout multiple launderings and dryings. Note that netting could also be used with untwisted web elements to improve the durability thereof when used in mops. 
     The above-described twisted web element can also be fabricated to define a number of tack points at a number of places along the web element&#39;s helical gaps. For example,  FIG. 10  illustrates a twisted web element  20  (similar to that described above and shown in  FIG. 6 ) with a number of tack points  20 P being formed along gaps  20 G. Each tack point  20 P is a point of self-fusing between two fused beads  20 F. Tack points  20 P could be provided for by adjusting the amount of heat and/or dwell time for such heat application during processing. 
     The advantages of the present invention are numerous. The twisted web element defines a memory-altered tubular structure that absorbs and retains liquid and/or particulate from a floor surface via its well-defined and maintained gapped, tubular structure. Maintenance of the gapped and tubular structure is achieved via self-fused edges and regions of the twisted web element that do not impede liquid/particulate absorption, retention, or release. The tubular structure of the twisted web element is retained even throughout multiple uses and multiple launderings. 
     Although the invention has been described relative to a specific embodiment thereof, there are numerous variations and modifications that will be readily apparent to those skilled in the art in light of the above teachings. For example, since twisted web elements in accordance with the present invention will retain their shape, the present invention could be used to produce mops with cut ends, i.e., free end loops  28  shown in  FIGS. 1 and 2  are essentially cut off from mop head  12  leaving open-ended twisted web elements. In another embodiment, rather than starting with planar strips (or web elements as they are referred to herein), the present invention could be adapted for use in making twisted fiber products where the individual fibers in the product experience fusing. In this case, fusing will generally occur between adjacent fibers such that loosely-twisted fiber products will not readily separate during handling and use. Netting (such as that described above) could also be disposed about the length of such a twisted fiber product. In still another embodiment of the present invention, a twisted tubular web element could be set in its shape by undergoing a wetting-and-drying process where such processing effectiveness is governed primarily by the properties of the material(s) used for the web element. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described.