Elongated pile sub-assembly, guide apparatus and pile sub-assembly articles of manufacture

[0001] This application claims the benefit of U.S. Provisional Application No. 60/336,226, filed Oct. 29, 2001.

[0002] The present invention relates to an elongated pile sub-assembly, pile sub-assembly articles and a guide apparatus that is useful for the purpose of making a brush, or making a pile or bristle surface structure such as a floor covering, a wall covering or an automotive component. More particularly, the present invention concerns an elongated pile sub-assembly have a root end for secure anchoring of the elongated pile sub-assembly on or through a substrate.

[0003] The following disclosures may be relevant to various aspects of the present invention and may be briefly summarized as follows:

[0004] Conventional tuftstrings made from yarn are normally in a U shape when attached or tufted into a backing substrate. The U shape is formed when a yarn segment is attached to an elongated strand near the medial point of the yarn segment. This U shape is similar to that of a needle tufted yarn which also forms two distinct and identifiable tufts from one yarn segment. This U shaped tuftstring is disclosed in prior art such as WO 99/29949 to Veenema et al., and U.S. Pat. No. 5,472,762 to Edwards et al.

[0005] A U shaped tuftstring for wall or floor coverings is normally attached to a backing structure first, to form a pile fabric or carpet. The point of attachment for the U shaped tuftstring is at the bottom of the U shape, which is also where the yarn and the support beam bond to one another. This bond area is generally a solid mass of fibers fused together providing only a small surface area to contact with and bond to a support substrate. The bond between the U shaped tuftstring can be formed using a thermal or solvent fusing process, adhesives, or mechanical interlocking means. This small contact area generally produces low tuft-lock values (e.g. the force at which the bond fails). Additionally, the rounded bottom of the U is susceptible to rotation (see FIGS. 1B and 1C) which can cause undesirable visible defects. FIG. 1C shows one example of the effect of such rotation on a U shaped tuftstring. The bottom of the U tips or tilts to one side when aligned with a ridgeline 105a on the surface of a substrate 105 having an embedded reinforcement fiber. This form of rotation causes density variations in the finished product. Another example of U shaped tuftstring rotation is the undesirable visible defect that occurs when the tufts on one side of the U have a higher frictional drag than the opposite side tuft during the insertion/bonding process causing the tuftstring to pivot laterally (see FIG. 1B). When this occurs, one row of tufts effectively becomes longer while the other row is effectively shortened by the same incremental length. These linear variations or visible defects are referred to as rowiness.

[0006] Additionally, when an adhesive is used for attaching the U shape to a substrate, the top surface of the adhesive is generally above the reference plane 300 of FIG. 5B and thus, an unwanted, performance altering (e.g. reduction in the softness of the pile) wicking of the adhesive into the tuft may occur.

[0007] Another disadvantage of the U shaped tuftstring, is that the two yarn ends of the U shaped tuftstring have a sizable gap between them when manufactured. This gap is reduced when the tuftstring is positioned in close proximity to other tuftstrings due to compression or interference with other tufts from adjacent tuftstrings. However, this compression or interference may be another source of density variations as some of the pile filaments may be separated such that they are all not in vertical alignment. Some filaments are directed toward the substrate and bonded thereto or otherwise entangled such that they are not a part of the desired pile density.

[0008] U.S. Pat. No. 5,470,629 to Mokhtar et al. describes making pile tuftstrings where each tuftstring is made by wrapping yarn around a mandrel on which a support strand is translated. As the support strand moves, it transports wraps of yarn to an ultrasonic welder which connects the wraps to the support strand. The bonded wraps are further transported to a slitter station which cuts the wraps and thereby forms the tuftstring. The tuftstring includes two rows of upstanding legs or tufts which are attached at their bases to the support strand. The yarn of Mokhtar et al. is a multifilament, crimped, bulky yarn that is made preferably of a thermoplastic polymer, such as nylon or polypropylene. The support strand is likewise preferably a thermoplastic polymer so that, when passed under the ultrasonic welder, the yarn and support strand melt to form a bond therebetween.

[0009] It is desirable to have an elongated pile sub-assembly that has a high tuft-lock value, controlled wicking and vertical alignment. There is also a need for a low-cost elongated pile sub-assembly, containing bundles of fibers arranged to provide a high density, that can be made by a simple, inexpensive method, and is designed to be packaged, or used directly as a feed material for making a brush or a pile/bristle surface structure. There is also a need for a strong, reliable elongated pile sub-assembly that can be packaged and handled in a fabrication process. It is also desirable to have a guide apparatus to bond the elongated pile sub-assembly to a substrate.

[0010] The elongated pile sub-assembly of this invention includes a continuous length support beam having a longitudinal axis, a uniform or substantially uniform cross-sectional size and shape, a peripheral surface, a reference plane tangent to or coincident with a location on the surface of the support beam, and a plurality of bundles of filaments secured to the support beam. The filament bundles have long bundle segment ends opposite the short bundle segment ends. The filaments on an end of at least one bundle (e.g. the long bundle segment ends) define a pile-forming tuft. There is a region in each bundle in which the filaments are densely-packed together and are generally bonded together, and the bundle is preferably secured to the support beam at the location of the densely-packed region.

[0011] Briefly stated, and in accordance with one aspect of the present invention, there is provided an elongated pile sub-assembly comprising: an elongated beam having a longitudinal axis, a substantially uniform cross-sectional size and shape, and a peripheral surface; and at least one bundle of filaments being secured to the peripheral surface of the beam; wherein the at least one bundle is secured to the beam at a location along the length of the bundle that divides the length into a longer bundle segment and a shorter bundle segment on either side of the longitudinal axis, said longer bundle segment defining a pile-forming tuft.

[0012] Pursuant to another aspect of the present invention, there is a brush comprising: a first brush body member, and at least one elongated pile sub-assembly secured to the first brush body member.

[0013] Pursuant to another aspect of the present invention, there is a pile or bristle surface structure comprising: a substrate, and an elongated pile sub-assembly secured to the substrate.

[0014] Pursuant to another aspect of the present invention, there is a guide, comprising: a groove for holding an at least one elongated pile sub-assembly according to any one of claims 1-19, having an at least one short bundle segment end, said short bundle segment end extending out of the same side of the guide as the groove, and means for attaching the at least one shorter bundle segment end to a substrate, wherein the guide is used to join the at least one elongated pile sub-assembly to said substrate.

[0015] Pursuant to another aspect of the present invention, there is a method for joining an elongated pile sub-assembly to a substrate using a guide, comprising: guiding the elongated pile sub-assembly through a groove with the shorter bundle segment extending externally beyond the groove in said guide; applying a bonding means to at least one of the substrate and the shorter bundle segment; moving the substrate and the shorter bundle segment into bonding contact with one another; and securing the shorter bundle segment extending beyond the groove to the substrate.

[0016] The invention will be more fully understood from the following detailed description, taken in connection with the accompanying drawings, in which:

[0017] FIG. 1A shows the prior art of a conventional U shaped tuftstring;

[0018] FIGS. 1B and 1C are elevational end views of the prior art showing visible defects resulting from U shaped tuftstring rotation;

[0019] FIG. 2B shows a rooted tuftstring of the present invention;

[0020] FIGS. 2A, 3A, and 4 are elevational end views of the elongated pile sub-assembly of the present invention showing different root end penetration;

[0021] FIG. 3B shows elevational end views of a plurality of rooted tuftstrings shown in FIG. 3A with the entanglement of the rooted filaments;

[0022] FIG. 5A is a perspective view of an elongated pile sub-assembly of the present invention;

[0023] FIG. 5B is a prior art perspective view of an elongated U shaped tuftstring;

[0024] FIG. 6 is a diagram showing one way to measure the diameter of a pile yarn;

[0025] FIG. 7 is a simplified representation of a section along the center of an elongated pile sub-assembly support beam showing tufts bonded to the beam in a single layer with the roots extending below;

[0026] FIG. 8 is a simplified representation of a section along the center of a rooted tuftstring support beam showing bundles bonded to the beam in an overlapping relationship;

[0027] FIG. 9A is a diagrammatic view of a simple process for making the elongated pile article of the present invention;

[0028] FIG. 9B is an end view of FIG. 9A showing a second slitter;

[0029] FIG. 10 is a side elevational view of a paint roller pile assembly using the present invention;

[0030] FIG. 11 is an end view of the paint roller of FIG. 10;

[0031] FIG. 12 is an end elevational view of an embodiment of a plurality of elongated pile sub-assemblies;

[0032] FIG. 13 is an end elevational view of an embodiment of an elongated pile sub-assembly bonded using an ultrasonic weld;

[0033] FIG. 14 is an end elevational view of a plurality of elongated pile sub-assemblies of the present invention attached via adhesive pile tape to a core;

[0034] FIG. 15 is a diagramatic illustration of a method of making a pile or bristle surface structure from elongated pile sub-assemblies of this invention;

[0035] FIG. 16 is a schematic illustration of a guide used in attaching or bonding elongated pile sub-assemblies of the present invention to a backing substrate or bonding material;

[0036] FIG. 17 is a schematic illustration of an elongated pile sub-assembly guide for bonding with flexible materials; and

[0037] FIG. 18A and FIG. 18B show elevational views of two embodiments of an ultrasonic horn used for bonding in the present invention.

[0038] The following definitions are provided as reference in accordance with how they are used in the context of this specification and the accompanying claims:

[0039] 1. Beam or Base String: A strand, string or cord composed of one or more materials and having one or more separate structural components, each having its own defined and identifiable shape. The beam or base string provides connectivity and support to tufts attached thereto.

[0040] 2. Bristle: A short stiff fiber segment natural or man-made generally referred to as in diameters measured in thousandths of an inch.

[0041] 3. BCF or BCF Yarn: bulk continuous filament yarn; a textured continuous-filament yarn, generally used either as a pile yarn in carpets or for upholstery fabrics.

[0042] 4. Tuftstring: A beam having attached to it at least one segment of yarn consisting of one or more filaments each having a diameter such that the diameter is reported in units of denier rather than thousandths of an inch (mils).

[0043] 5. Rooted Tuftstring or Elongated Pile Sub-Assembly: A Tuftstring where the beam or base string divides the long bundle segments from the short bundles segments. The short bundle segments also called roots are the non-bonded yarn fiber that attaches the tuftstring to substrates (i.e. other articles or base materials). The long bundle segments are the non-bonded yarn fiber end that forms the pile or bristle end of the tuftstring.

[0044] 6. Denier: The mass in grams of 9000 meters of a fiber, filament, or yarn.

[0045] 7. Fiber: Textile raw material, generally characterized by flexibility, fineness and high ratio of length to thickness.

[0046] 8. Filament: A fiber of indefinite length.

[0047] 9. Filament Yarn: Normally continuous filament. A yarn composed of one or more filaments measured in denier units that run essentially the whole length of the yarn.

[0048] 10. Yarn: A product of substantial length and relatively small cross-section consisting of fibers and/or filaments with or without twist.

[0049] The rooted tuftstring of this invention may be understood from a general description of a method by which it may be produced. This method involves: feeding a continuous length of a bundle of filaments under tension along the center of rotation of an eccentric guide; rotating the guide to wrap the bundle of filaments around a support having a plurality of elongated ridges to form a succession of wraps or flights of the continuous length of a bundle of filaments that envelope the support; feeding a continuous strand of material along at least one of the ridges on the support, between the support and the flights of the bundle of filaments formed by the step of wrapping, to provide a beam; bonding the filaments in the bundle to each other and securing the bundle of filaments to the beam; cutting the flights of the bundle of filaments to form an elongated pile sub-assembly; and forwarding the elongated pile sub-assembly for further processing. Reference is made to U.S. Pat. No. 5,547,732, WO 99/29949, and U.S. Pat. No. 5,498,459 whose contents are herein incorporated by reference as examples of the above method of forming a U shaped tuftstring. In the present invention, however, the above prior art references are differentiated from the present invention in the cutting step to produce the rooted tuftstring. A distinguishing difference, in the present invention, is the position of the rotating slitter knives relative to the bonded beam (e.g. base string). In the above referenced patents, the slitters are positioned so as to form two tufts of substantially equal length from one continuous yarn segment. In the present invention, the slitters, or the bonding position of the beam, or both are repositioned so as to produce a tuftstring with a first bundle of filaments segment for use as the pile surface and a second bundle of filaments segment for use in anchoring the tuftstring to a fabric or other support structure, such that the first segment is generally longer than the second segment. (See FIGS. 9A and 9B). The above references are examples of machine methods capable of producing tuftstrings with the modified cutting step but are not all-inclusive. There are a variety of machine methods that are applicable to producing the rooted tuftstring of the present invention.

[0050] In the U shaped tuftstring (see FIG. 1A) the bundle of filaments is cut such that the base string 101 is substantially equidistant from the cut end of each bundle segment of the tuftstring 108. In FIG. 1A, the U shaped tuftstring 108 has an equal bundle segment length 109a and 109b on either side of the base string 101. The tuftstring 108 is bonded to the adhesive backing 107 at the six o'clock position 101a. A disadvantage of the U shaped tuftstring approach is that the bundle segment lengths 109a and 109b can appear to be uneven when assembled with other U shaped tuftstrings (See 1B and 1C). This can occur in a variety of ways. For example, the base portion of the U shaped tuftstring may roll or rotate as it is guided and secured to the backing. More friction on one bundle segment 109b than on bundle segment 109a, for example, would generate a torque and cause the U shaped tuftstring to rotate counter clockwise as shown by arrow 103a (see FIG. 1B). Another cause can be attributed to an uneven substrate surface such as when a reinforcement fiber is present and generates a ridgeline 105a on the surface. Referring to FIG. 1C, when first side 109a of the U shaped tuftstring contacts the substrate surface before second side 109b, a torque force is again established when the velocity or motion is normal to the plane of the substrate and can cause the tuftstring to rotate or lean. The leaning effect shown in FIG. 1C, can also cause a space 132 between the tufts which creates an undesirable spacing defect or at least causes density variations in the finished pile.

[0051] The present invention (see FIGS. 2A, 2B, 3A, and 4) utilizes a modified tuftstring that improves the bond strength between the tuftstring and the substrate fused to bind multiple tuftstrings together (for example, as in a carpet), especially when adhesives are used as the bonding agent. Thus, eliminating the need in the present invention (e.g. one long bundle of fibers segment side 126 and one short bundle of fibers segment side 127, 128, 129) to fold the yarn tufts into a conventional U formation. The long bundle segments 126 are arranged together as a continuous row of long bundle segments in the proper orientation for functional value, while the short bundle segments 127, 128, or 129 are used to anchor the elongated pile sub-assemblies 125 to the backing substrate with the aid of an adhesive or other means, such as ultrasonic bonding or solvent bonding.

[0052] In the present invention, the yarn used in the elongated pile sub-assembly 125 (see FIG. 2A) is a multifilament strand where the filaments are typically connected to one another. The filaments are connected in that they may be twisted at a level of at least about 1 turn/inch to provide filament crossovers that enhance bonding (especially ultrasonic bonding), or the filaments may be interlaced to provide crossovers. The yarn may also comprise two or more strands of multifilaments that are ply-twisted together. The ply-twisting may be a true S or Z strand and ply twist, or a reverse twist where the S and Z strand and ply twist alternate and there is a bond in the ply and strand twist reversal. Preferably the reverse twisted yarn has a bond in the plied yarn before reversing the twist, as described in U.S. Pat. No. 5,012,636. One such yarn is preferably made from crimped, bulky, heat-treated filaments and is commonly used as carpet yarns. The filaments of the yarn may have a variety of cross-sections which may be hollow and contain antistatic agents or the like. The yarn may have a finish applied that aids in ultrasonic bonding. The yarn may in certain preferred embodiments be a multifilament, crimped, bulky, ply-twisted yarn that has been heat set to retain the ply-twist.

[0053] In other applications where a velour surface is preferred, such as in automotive flooring and paint rollers, another type of yarn is preferred. Such a yarn includes one in which the multifilaments of the BCF yarn are loosely entangled and are not heat treated. For automotive or other transportation use, the rooted tuftstring (i.e. elongated pile sub-assembly) preferably made of BCF singles yarn, that is not twisted, ply-twisted, or otherwise entangled to form individual long bundle segments as described in WO 99/29949.

[0054] When using ultrasonic bonding means to form the rooted tuftstring, the yarn, (preferably made from a thermoplastic polymer having the same composition as the beam,) achieves high bond strength of the yarn bundles to the beam. In some ultrasonic bonding applications, the yarn and the beam can be of different compositions and still achieve adequate bonding between the two. One such example is a nylon yarn bonded to a polypropylene beam. It is further noted that in bonding methods other than ultrasonic bonding, using the same composition for beam and yarn provide high bond strength and avoid the need for adhesives. However, adequate bonding of different compositions for the yarn and beam in bonding methods other than ultrasonic are also adequate.

[0055] When using an adhesive method to bond the yarn to the beam, the composition of the yarn and the beam is selected according to the range of suitable materials the adhesive can bond with or, the adhesive is selected according to the selection of yarn and beam composition. It is important that the bond between the yarn and the beam be adequate to deliver the yarn to the support structure without loss of yarn segments or individual fibers from a yarn segment. Once the short segment fibers are bonded to the substrate, the bond strength between the beam and the yarn bundles becomes less significant.

[0056] In the present invention, the yarn is typically a thermoplastic polymer such as a polyamide, a polyolefin such as polyethylene or polypropylene, a polyester, a fluoropolymer, polyurethane, polyvinylchloride, polyvinylidene chloride, or a styrenic polymer or copolymer, including mixtures of two or more thereof, and the like. Polypropylene; or a polyamide such as nylon 6; nylon 11; nylon 6,6; nylon 6,10; nylon 10,10; and nylon 6,12 is preferred. The yarn may alternatively be a poly (aryletherketone) or a polyaramid or meta-aramid that is bondable with solvents, ultrasonics, or heat.

[0057] The beam useful in the elongated pile sub-assembly may have a variety of cross-sectional shapes, such as square, rectangular, elliptical, oblong, round, triangular, multi-lobal, flat ribbon-like, etc. The beam must be bondable to the yarn and have sufficient elongational stability so the bonds are not over-stressed due to stretching of the beam or its tensile strength exceeded. The beam must provide sufficient stability to the pile sub-assembly such that it can be handled for its intended use, such as manufacturing a brush or manufacturing floor covering articles, such as a carpet or rug. The beam may be a monofilament, a composite structure, a sheath/core structure, a reinforced structure, or a twisted multifilament structure. The beam is preferably made from a thermoplastic polymer so the yarn beam can be bonded without use of adhesives. The beam is more preferably a polymer having a molecular structure oriented in the elongated direction, and having a low dimensional change in the direction of orientation due to moisture gain or loss or modest temperature changes. One material for use as the support beam is a monofilament nylon polymer, such as Tynex made by E. I. du Pont de Nemours and Company. Other materials for use as the support beam include polypropylene and polyethylene. In some applications, one or more of the polymers named above can be combined, such as in coextrusion to form a bi-component beam.

[0058] Filament production may be accomplished by the use of an extruder, many varieties of which, such as a twin-screw extruder, are available from manufacturers such as Werner and Pfleiderer. A polymer in the form of granules is fed from a feeder unit into the extruder either volumetrically or gravimetrically. A slip agent is fed from a separate feeder into the extruder through a side-arm port, and is blended with the polymer in the extruder at a temperature of 150-285 C. Alternatively, the slip agent can be pre-compounded or pre-blended with the polymer so that a separate feed system is not required. The polymer and slip agent are mixed as a melt in the extruder, and the resulting composition is then metered to a spin pack having a die plate. The composition is filtered, and filaments of various shapes and sizes are produced by extrusion through the holes in the die plate.

[0059] Similar to the support beam discussed above, the filaments from which the bundle of filaments is prepared may have a variety of cross-sectional shapes, as determined, for example, by the shape of the die plate orifice when production is by extrusion. The shapes include but are not limited to round, oval, rectangular, triangular, or the shape of any regular polygon; or the filament or beam (discussed above) may be an irregular, non-circular shape. Additionally, the filament or beam may be solid, hollow or contain multiple longitudinal voids in its cross sections. Each run of an extruder can produce any combination of cross-sectional shapes by using a die plate with various shaped holes. Filaments or beams of one or more diameters may be made at the same time by varying the size of the holes in the die plate. Alternatively, the filament and/or beam used in this invention may be produced by solution spinning.

[0060] Another aspect of this invention involves the use of a filament and/or beam having a sheath/core construction. The sheath surrounds the core in a coaxial or concentric configuration. The polymer used in the core and the sheath may be the same or different. When dissimilar polymers are used, the properties of the polymers must be such that they can be co-extruded, drawn to diameter and wound onto spools. Nylon 6,6 is preferred as a sheath material. A sheath/core filament or beam is typically produced by coextrusion using two extruders sharing a common spin pack. The polymer used to make the core is channeled from a first extruder to the center of the spin plate holes, and the composition used to make the sheath is channeled from a second extruder to the outside of the spin plate holes.

[0061] A sheath/core filament of yarn, or a beam in filament form, which is produced from more than one source of flowable polymer or polymeric composition, as described above, may be distinguished from a filament that is produced from a single source of flowable polymeric composition. Such a single-source filament may be referred to as a single composition monofilament. For a beam, the filament used in the present invention may be either a multi-component or a single component monofilament, with a single component monofilament being preferred.

[0062] A filament for use in the bundle of filaments in this invention has a diameter, or maximum cross-sectional dimension, as determined by the diameter of the smallest circle in which it is circumscribed, of about one or more, preferably about two or more, and most preferably about 2.5 or more, and yet about 15 or less, preferably about 10 or less, and more preferably about 5 or less, mils. (A mil is 0.025 mm.)

[0063] A filament or beam for use in this invention may be prepared from a polymeric composition as described above containing typical additives such as fillers, colorants, stabilizers, plasticizers or anti-oxidants, or a mixture of more than one thereof; or may be prepared with a surface coating.

[0064] Reference is now made to FIGS. 2A4 which show different end views and encapsulation embodiments of the root end of an elongated pile sub-assembly, or rooted tuftstring 125 of the present invention. FIG. 2 shows an end elevational view of an elongated pile sub-assembly with the short filament bundle segment 127 penetrating the adhesive 117 and backing substrate 115. FIG. 3A shows an end elevational view of an elongated pile sub-assembly with the short filament bundle segment 127 having a flared penetration 128 of the adhesive 117 and the backing substrate 115. FIG. 4 shows an end elevational view of an elongated pile sub-assembly with the short filament bundle segment 127 having surface flaring 129 in the adhesive 117. In FIGS. 2A4 the short filament bundle fibers are totally encapsulated for a strong anchoring of the elongated pile assembly 125. Another variation, not shown, is where all the roots 127 of FIG. 2 lay horizontally to one side.

[0065] With continuing reference to FIGS. 2A4, the ultimate position of the roots of the tuftstring is mostly dependent on the characteristics of the substrate and the stiffness of the root filaments. An open, non-woven substrate would easily permit the roots to penetrate the fabric structure without much deflection of the roots as shown in FIG. 2A. Tightly woven fabrics offer more resistance and deflect more of the roots upon entry into the fabric as depicted in FIGS. 3A and 3B. A highly dense non-woven fabric, like Tyvek or a solid sheet, such as an extruded thermoplastic structure would prevent penetration by the filament roots into the substrate structure causing complete deflection 129 of the short segment fibers 127 as shown in FIG. 4.

[0066] Referring now to FIG. 5A which shows a plurality of bundles of filaments 154, as yarn that has been secured to a support beam 119 at a location 73 on the peripheral surface thereof. The longer bundle segment 126 of the elongated pile sub-assembly 125 defines a pile-forming tuft. The shorter bundle segment 127 of the elongated pile sub-assembly 125 defines the root forming tuft.

[0067] Referring now to FIG. 2A which shows the elongated pile sub-assembly 125. The bundle of filaments 154 is bonded to the beam 119 to form the elongated pile sub-assembly. The bundles of filaments 154 has, along its length, a densely-packed region 162 where the filaments are generally bonded together, and which is the location where the bundle is secured to the support beam 119.

[0068] Referring again to FIG. 5A, a support beam 119 has a uniform, or substantially uniform, cross-sectional size and shape, and a peripheral surface 133. The densely-packed region 162 (FIGS. 2A4) along the length of the elongated pile sub-assembly 154 where the filaments are bonded together is secured to the peripheral surface 133 of the support beam 119 parallel and adjacent thereto. The bundle of filaments 154 is secured to the peripheral surface 133 (perpendicular to the reference plane 71) of the beam across all, or across a substantial portion of, the densely-packed region 162. Contained within the bundle of filaments 154 are filaments that are substantially linear, and thus have opposing ends 202 and 204. The opposing ends of the filaments define a length of the bundle. The bundle 154 is secured to the beam at a location along the length of the bundle that divides the length into a longer bundle segment 126, which has a longer length, and a shorter bundle segment 127, which has a shorter length, on either side of the longitudinal axis 140 of the beam 119.

[0069] The longer bundle segment 126 contains longer filament segments, and the length of the longer bundle segment is measured from the location that divides the filament bundle 154 into longer and shorter bundle segments to the end 202 of the longer filament segment contained in the longer bundle segment. The longer bundle segment 126 is pile-forming at the cut ends 202 of the longer filament segments. The shorter bundle segment 127, contains shorter filament segments, and the length of the shorter bundle segment is measured from the location that divides the filament bundle into longer and shorter bundle segments to the end 204 of the shorter filament segments. The usable portion of the longer bundle segment 126 and the shorter bundle segment 127 are on opposite sides of the densely packed region of the filament bundle 125. The shorter filament segments define roots that have substantial utility in anchoring the tuft particularly when the pile sub-assembly is used to make a brush, pile surface structure or other articles, as described herein.

[0070] The length of the shorter bundle segment 127 (FIG. 2A) is preferably about 90 percent or less than the length of the longer bundle segment 126. In other embodiments, however, the length of the shorter bundle segment may, as desired, be about 75 percent or less, about 50 percent or less, about 25 percent or less, about 10 percent or less, or about 5 percent or less, than the length of the longer bundle segment. The length of the shorter bundle segment preferably exceeds about 10 percent of the width of the beam. For example, if the beam width is 200 mil then the roots need to be longer than 20 mils. (It is further noted that the longer the short bundle segment 127 when attached to the substrate, the more secure the anchoring of the elongated pile sub-assembly 125). The width of the beam is defined as the smallest of the following quantities: (i) the distance across the cross-sectional area of the beam 74, as shown, for example, in FIG. 5A, measured through and perpendicular to the longitudinal axis of the beam and parallel to the reference plane 71; (ii) the diameter of the smallest circle that completely circumscribes the cross-sectional area of the beam; or (iii) in the case of a cross-sectional area of the beam that is a true rectangle, the longer of the two dimensions of the rectangle. In further embodiments, however, the length of the shorter bundle segment may, as desired, exceed about 55%, about 60%, about 75%, or about 100% of the width of the beam.

[0071] Six test samples of rooted tuftstring were tested for anchoring strength using an Instron (Model 1125). The rooted tuftstring samples were 1.00 long having a short segment length of 0.090 inches and a long segment length of 0.265 inches. Two test cells, repeatedly used, were fabricated having the following cavity dimensions: 1.00 long by 0.185 wide and 0.25 deep to receive an adhesive. A hot melt adhesive of Profax Polypropylene PF611 CT distributed by the H. A. Hanna Company was used. The test cell was heated and filled with the Profax Polypropylene PF611 CT adhesive. The rooted tuftstring sample was placed into the test cell such that the short segment fibers only were subsurface in the adhesive melt. The rooted tuftstring, adhesive and cell were then allowed to cool to room temperature before testing for anchoring strength. The Instron clamping device was fastened to the test cell and another to the long segment fibers of the rooted tuftstring. The Instron test instrument was used to detect the peak force applied to the clamps at the moment of failure of the roots. The goal of these tests was for the rooted tuftstrings to have an anchor strength greater than 15 lbs. In test after test, there was no failure observed of the bond between the short segment fibers and the solid adhesive resin within the test cell. The type of failures observed were: 1) between the adhesive and the test cell walls which were the most common failures; and 2) the remaining failures were the yarn fibers that failed in the vicinity of the bond between the yarn fibers and the beam. All failures of the adhesive to the test cell and of the yarn fibers occurred at tensions exceeding 45 pounds. These results far exceeded the minimum desired goal of 15 pounds.

[0072] It is important to realize that the roots of each yarn bundle are in a three dimensional space when anchored into a substrate. For example, FIG. 4 shows the roots spread to the left or right of the bundle vertical center in this end view. While this orientation 129 of the short bundle segments 127 can occur, they are more likely spread 360 degrees from the vertical center of the bundle 125 within a plane parallel to and a plane below the reference plane 71 of FIG. 5A. In FIGS. 2B and 3A, the roots are spread in a cone shape below the reference plane 71 (FIG. 5A), each having a center vertical axis generally tangent to or coincident with the yarn bundle side vertical peripheral surface of the beam. FIG. 2B is a narrow cone, while FIG. 3A is more hemispherical.

[0073] In an embodiment of the present invention, FIG. 5A shows the elongated pile sub-assembly in which the bundle of filaments is secured to the support beam 119, which may be accomplished by ultrasonic bonding or other means. The filaments of the short bundle segment 127 are used as the anchoring point of the elongated pile sub-assembly 125. By comparison, the U shaped tuftstring of the prior art, utilizes the dense portion 101a (see FIG. 1A) of the filament bundle and the bond line formed between the support strand and the yarn bundles as the anchoring surface. This area has the characteristics of a solid mass, and as such, the only surfaces available for an adhesive to connect with, are the outer peripheral surfaces of the yarn/strand mass. This is a limiting characteristic of the prior U shaped art. By contrast, the short bundle segments 127 (FIG. 2B) of the present invention, have substantial surface area due to the roots (e.g. fibers of the short bundle segments) it provides to anchor the filament bundle in an adhesive media 117. In the present invention, the roots are filament segments that are continuous with and extending in the opposite direction of the pile forming filament segments. The proximal end of the short filament segments or roots are bonded to the beam and are thus fixed in position and have limited surface area in that regard. However, the remaining length of the short filament segment roots can and do provide considerable surface area. In the simplest case where the cross-section of the filaments is round, the surface area is simply the surface area of a cylinder.

[0074] Comparison by example of the surface area of the U shaped tuftstring to that of a rooted tuftstring of the present invention, clearly shows the benefit of the present invention. For example, when using a 28 mil beam and a 1500 denier, two-ply yarn bonded to the beam to form both a U shaped tuftstring and a rooted tuftstring, the adhesive bonding surface area of the U shaped tuftstring is 0.060 square inches per inch of tuftstring whereas for a rooted tuftstring, having a 0.063 inch length of short segment fibers and eleven (11) tufts per inch, it is found that the surface area is 0.864 square inches per inch of tuftstring. This is a 1,340 percent increase in available surface area for the adhesive to bond with.

[0075] In addition, these unconstrained distal filament ends of the short segment fibers can interact and entangle 121 with the (fibrous) structure of the substrate as shown in FIG. 3B for added anchoring strength. The fibrous roots of the present invention are encapsulated and mechanically locked into the adhesive media when it freezes. This mechanical bond replaces the need for a strong chemical or thermal bond to anchor the tuftstring to a support substrate and therefore greatly expands the opportunity to use lower cost, and environmentally friendly adhesives.

[0076] Referring to FIGS. 2B4, the filaments of the short bundle segment 127 act as a wick and draws the adhesive into the void spaces between the filaments generating a matrix structure such as found in resin composite structures. The dense portion of the filament 162 limits the travel of the adhesive from migrating up into the long bundle segment 126 by forming a barrier zone. In this embodiment, the opposing ends 202, 204 of the filaments define a length of the bundle. This bundle has longer and shorter bundle segments, characteristics related to the length of the longer and shorter bundle segments, and varied orientation 128, 129 of the shorter filament segments when attached to a support substrate, as described above.

[0077] Where yarns with strong interconnections among the filaments are used, it may be preferable to comb out the short segment portion of the rooted tuftstring so that filament to filament entanglement is minimized to permit the short segment fibers to better disperse into the adhesive and support substrate.

[0078] A further characteristic of the bundle of filaments utilized in the elongated pile sub-assembly of this invention is that (1) at least one bundle is divided into (a) a first segment, comprising first filament segments, on one side of the location at which the bundle is secured to the beam, having a first stiffness, and (b) a second segment, comprising second filament segments, on the other side of said location, having a second stiffness. The change in stiffness of a filament is proportional to the fourth power of the effective cross-sectional area and to a third power of the length. Thus for a given diameter, the relative stiffness will decrease by 87.5% when the unrestrained length is doubled, assuming no interactions with adjacent filaments. Therefore the stiffness of the short segment bundle can be slightly higher or orders of magnitude stiffer than the longer segment bundles depending solely on the ratio of length.

[0079] Depending upon the product to be made from rooted tuftstring, the length of the short segment is selected based on these characteristics such as stiffness and anchoring strength to the substrate. Longer short segment fibers have reduced stiffness and therefore will be more likely to mat down such as in FIG. 4. Shorter short segment fibers will be stiffer and have a greater potential for puncturing the surface plane of the support substrate such as shown in FIG. 2. As expressed earlier, the denier of the fiber filaments also influences the extent to which fibers will puncture or penetrate into the substrate. Longer short segment fibers may entangle with adjacent rooted tuftstrings and thus, share bonding force with adjacent tuftstrings (see FIG. 3B). However, there is a limit to the desired length of the short segment fibers. At some length, determined by composition, cross-section, shape, etc., the bond strength of the roots can exceed the failure strength of the fiber in the dense portion of the rooted tuftstring. Thus, there is no value in increasing the length of the roots unless the purpose is to strengthen the substrate material. Cost is also a consideration here. As short segment fiber length is increased, the raw material cost increases as well. An optimum length can be selected based on the material chosen and testing that ensures adequate anchoring strength in a desired cost range.

[0080] In a preferred position the beam is positioned between the supply yarn and the mandrel as the supply yarn is wrapped around the mandrel (as described in U.S. Pat. No. 5,472,762, incorporated by reference above). In an alternative embodiment, however, the beam can be secured to the wraps or flights of yarn such that the wraps are positioned between the beam 119 and the mandrel. The characteristics of the densely packed, bonded region remain the same as described with reference to FIG. 2A.

[0081] The unique geometry of the pile sub-assembly is described below, and is presented normalized by expressing dimensional features as a ratio to the free yarn bundle diameter. The yarn bundle diameter is a parameter that is related to the ability of the yarn to cover a surface in an efficient manner in a fabricated article. For repeatability in measuring, the yarn bundle diameter is the untensioned average diameter of a one inch long straightened section of a longer bundle segment remote from the cut ends to avoid the ambiguity that flaring of the cut ends may cause when making a measurement. The yarn bundle diameter can be repeatably measured using a microscope with grid lines or an optical comparator, such as a Qualifier 30 made by Opticom. FIG. 6 shows a view of the yarn on the Qualifier 30. A one inch piece of straight yarn with no cut end flare (which may be straightened with very low tension that does not appreciably compact the yarn) is placed on top of a flat block 181 located in the light path of the comparator. At a 20 magnification, the sample 182 is aligned with a horizontal line 184 on the comparator screen that is passed through the peaks and valleys along the edge of the sample to define an average edge location. The line is moved to the opposite average edge of the yarn at position 186 and the distance moved 188 is recorded as the average diameter of the one inch long sample. This may be repeated with several samples of the supply yarn to further average the diameter. In the case where there are different diameter bundles along the beam, the bundle diameter would be the average diameter of all the, different bundle diameters along a representative length where the pattern of different diameters repeats. The bundle diameter of a yarn may be about 0.114 inches, and is preferably between 0.020 inches and 0.150 inches.

[0082] As previously noted the present invention is applicable to both singles and twisted/plied yarns. The singles yarn is not a twisted or highly entangled bundle of fibers. There is a leveling of the loosely entangled filaments of the singles yarn by the ultrasonic horn in the bonding process which tends to average and redistribute the yarn filaments. The relationship of the bundles to each other along the support beam is defined by the pitch for twisted yarn, which is the distance between bundles along the support beam, by the width of the support beam, and by the bundle diameter. Singles yarn has no distinguishable P/D ratio.

[0083] The bundle pitch/bundle diameter ratio (P/D ratio) describes the distance between adjacent bundles of yarn (pitch) laid along a length of support beam compared to the yarn bundle diameter. The unique process of the invention allows the product to have a much denser distribution of bundles along the beam than other elongated pile articles taught in the art. When the yarn is wound onto the support beam there are at least three methods of achieving a high density of bundles on the beam: 1) apply enough tension to the yarn bundle that the diameter necks down such that when the necked down yarns are laid adjacently abutting each other along the beam, the pitch is less than the free untensioned bundle diameter; 2) wind multiple layers of yarn bundles on the beam; and 3) a combination of the first two.

[0084] In contrast to the U shaped tuftstring of the prior art, the P/D ratio for the rooted tuftstring will generally be two times (2) that of the U shaped tuftstring to achieve the same pile density. Since the second shorter segment of the fiber bundle is used to attach the rooted tuftstring to a support substrate, it is not available as pile for the exposed surface as is the case with the U shaped tuftstring. Doubling the pitch to achieve the desired density provides a corresponding density of roots to ensure a high anchoring strength for the rooted tuftstring.

[0085] The P/D ratio can be further appreciated referring to FIGS. 7 and 8. The bundles of yarn are bonded to the opposite side of the beam 119 shown as simplified tufts, 205a, 206a, and 208a. The simplified tufts are bonded to the beam at the densely packed region 162. The simplified rooted ends 205b, 206b, and 208b are shown extending past the beam. The pitch P of the bundles along the beam 119 is best understood referring to FIG. 7 and looking at the abutted center-to-center spacing or pitch 210 between the dense bonded portions of adjacent bundles. It is preferable to measure pitch here instead of at the end of the tuft since the tuft ends are somewhat free to move about. The diameter of the bundle D is represented by the distance across an untensioned bundle or diameter 75. The pitch may have to be averaged along a one inch length to get a representative number as some local variations are to be expected.

[0086] FIG. 8 shows how the pitch is determined when there are multiple layers of bundles along the beam 119 and the simplified root end portions of the bundle bonds may overlap one another. Bundle tufts, such as 205a, 206a, 214a, and 215a are shown above beam 119 and the overlapped dense rooted end portions of the bundle bonds for these bundles are shown below the beam 119, as 205b, 206b, 214b, and 215b, respectively. The pitch P is the distance between adjacent dense portions 162 of bundles successively placed along the beam at pitch 210. Once again, the number of bundle bonds along a one inch section may need to be averaged to get a representative number for P. In the case where there are different diameter bundles along the beam, perhaps causing the pitch to vary considerably, the pitch would be an average represented by the reciprocal of the number of bundles per a representative length where the pattern of different diameters repeats. The bundle pitch may be about 0.033 inches, and is preferably-between about 0.015 and 0.150. The P/D ratio may be about 0.30, and is preferably between about 0.1 and 7.5.

[0087] The width of the support beam is an important parameter in the present invention for the following reasons: 1) it must have an outer perimeter sufficient in size to enable the use of the rooted tuftstring guide assembly (FIGS. 16 and 17); and 2) if it is too wide, it may cause the spacing between adjacent pile sub-assemblies to be excessive such that a dense array of yarn tufts in a fabricated article cannot be achieved. A rectangular beam has several advantages and is preferred, though other cross-sectional shapes can also be useful. The vertical side to which the yarn filaments are bonded has a larger surface than would for example, the intersection of the yarn with the tangential surface of a round or oval beam. The flat top and bottom surfaces are useful in aligning the pile segments vertically. The flat top of the beam pressed against a slightly larger flat of the guide assembly works in unison with the slot used to pass through the long fiber segments to prevent rotation of the rooted tuftstring as it is processed with a backing substrate. The horizontal flat bottom side of the beam provides a stable surface as opposed to curved surfaces such as those of a round or oval beam. The beam width is preferably 0.010 to 0.70 inches.

[0088] There is a structural feature, which is important in certain embodiments, that is related to the manner in which the bundle of filaments, i.e. yarn, is bonded in the densely packed region 162 to the beam 119. Continuous filaments within each of the yarn bundles, secured to the beam and further anchored to the substrate ensures a high probability of capture and high retention strength for each individual fiber. However, the higher strength has been found to be to the adhesive and not to the beam when the appropriate adhesives are selected. In the present invention the rooted tuftstring, for the reasons stated above, minimizes linting (e.g. loose fibers released from the pile article due to breakage).

[0089] Although the invention has been described above as being made on an automated device, an alternate embodiment of the invention can be made by manual means or any other suitable means. Referring now to FIGS. 9A and 9B, the supply yarn 20 can be wrapped by hand around a thin rectangular mandrel 282, for example, having support beams 119 taped or otherwise held in place along grooves 288 and 290. After the supply yarn 20 is in place, an ultrasonic horn 292 can be passed along the yarn, wrapped around grooves 288 and 290, to bond the yarn to beams 119. The yarn can then be cut by a cutter or slitter 294 at a predetermined location, proximal to the beam 119, on either side of the mandrel. For greater efficiency and speed, a slitter may be located above the beam in groove 288 as shown in FIG. 9A and below the beam 119 in groove 290 (see FIG. 9B) or vice versa. In this manner, two elongated pile sub-assemblies are easily produced. The first elongated pile-sub-assembly has short bundle segments relative to groove 288 at the end above the beam 119 cut by the slitter 294. The long bundle segments of the rooted tuftstring would be the portion extending from the 119 beam at groove 288 to the slitter 293 located below the beam 119 at groove 290 in FIG. 9B. The remaining slit yarn separated from the first elongated pile sub-assembly forms the second elongated pile sub assembly. If only a single rooted tuftstring assembly is desired, the second beam and slitter are omitted along one ridge. The mandrel can have a length 296 that is as wide as the carpet or article in which the rooted tuftstring is to be used.

[0090] To assist in wrapping the yarn, the mandrel may be mounted in a rotatable chuck and the yarn traversed along the rotating mandrel. A lathe with a traversing crosshead may be usefully employed to so place the yarn on the mandrel. In the most general sense, the product can also be made by laying one precut yarn bundle at a time over the beam and groove of the mandrel and bonding the bundle so that the wrapping step is not required.

[0091] One method for making an elongated pile sub-assembly of the present invention comprises: contacting an elongated support beam with a plurality of bundles of filaments at a location along the perimeter of the beam; bonding the filaments both, to each other (to form a dense portion in the bundle where the filaments are bonded together) and to the beam at a location along the beam. In the present invention, one method of bonding the supply yarn to the beam includes an ultrasonic driver such as a Dukane Corp. model 40A351 power supply capable of 350 watts at 40 KHz, connected to a Dukane Corp. 41C28 transducer. A Dukane booster may also be used. Bonding means other than ultrasonic bonding may also be employed to form the compacted portion of the bundle by securing the filaments to each other and to the beam. Such means may be solvent bonding or thermal bonding with, for instance, a hot bar; or some combination of solvent, conductive, and ultrasonic bonding. Or, an adhesive may be introduced to the location where the bundle is secured to the beam to form an adhesive bond between the bundle and the beam.

[0092] The elongated pile sub-assembly of the invention may be used to make a fabricated article such as a pile surface structure, including flooring articles, paint brush rollers, etc. or a brush surface structure, including toothbrushes, a buffing wheel, etc. A brush may be made in a variety of configurations, with or without a handle. The elongated pile sub-assembly of the invention may be used to form a pile brush face. The pile brush face is the portion of the brush that may be used, for example, to apply or remove a liquid material, or to alter a surface by the application or removal of a liquid material. The pile brush face on a brush may be generally planar in shape, or it may take on other shapes such as a generally cylindrical shape.

[0093] A roller brush, used for an activity such as the application of paint, is a typical example of a brush having a generally cylindrical pile brush face. The case of a roller brush may be illustrated, for example, as in FIGS. 10 and 11, which show a roller brush 310 having a pile covering 312 as a brush face mounted on a hollow core 314. The hollow core 314 can have any suitable shape, such as cylindrical or oval, depending upon the application. The pile covering 312 is made of at least one elongated pile sub-assembly 125 (FIG. 2A) having a support beam 119. The elongated pile sub-assembly 125 has at least one bundle of yarn secured to the support beam 119 in which a longer bundle segment 126 defines a pile-forming tuft as shown in FIG. 2A. The core of a roller brush is typically rotatable about a handle member, not shown.

[0094] With continuing reference to FIGS. 10 and 11, the pile covering 312 is formed by securing one or more pile sub-assemblies to the outer surface of the core 314. In a preferred embodiment, one or more pile sub-assemblies is wrapped spirally and continuously around the outer surface of the core 314. Alternatively, however, an elongated pile sub-assembly may be mounted on the core 314 in an alignment in which the elongated pile sub-assembly is longitudinal, i.e. parallel to the centerline axis of the core, or in an alignment in which it describes a circle about the longitudinal axis along the circumference of the core, or in other variations on any of such alignments as described. Elongated pile sub-assemblies may be secured to the core in parallel alignment to each other.

[0095] The elongated pile sub-assembly 125 (see FIG. 4) is secured to the core 314 by any suitable bonding means, including an adhesive binder applied to the outer surface of the core 314 immediately prior to a step of wrapping or otherwise affixing the pile sub-assembly to the core. Chemical or thermal binding processes may also be employed as well, however, in addition to other mechanical binders, such as anchors disposed at opposite ends of the core 314, or a hook and loop locking system. When a thermal binding process is used, it is preferred that the core and/or the elongated pile sub-assembly, or both, be prepared from a polymeric material. A portion of the core and/or a portion of the elongated pile sub-assembly, or a portion of both, may then be softened by inducing a temperature therein above the melting or glass transition temperature of the polymeric material. At a temperature above melting or glass transition, the softened polymeric material will flow, creating a zone of polymer flow. The increased temperature causing polymer flow may be attained by radiant or conductive heating means, but preferably by ultrasonic energy. As the polymeric materials from which the core is made flow and contact the elongated pile sub-assembly, or, as the polymeric materials, from which the elongated pile sub-assembly is made, flow and contact the core, or as both results occur, the flowing polymeric materials become welded and secured at the point of contact after they cool and resume solid state. As an alternative to increased temperature, the zone of polymer flow may be created by the application of a suitable solvent to any of the components that have been fabricated from a polymeric material.

[0096] The core 314 may be prepared from a polymeric material, as aforesaid, or can be prepared from paper and resin which have adhesive applied thereto. The core 314 can also include spiral windings of paper impregnated with resin to which adhesive and fabrics are applied to form a continuous profile.

[0097] In one embodiment, a pile covered fabric is prepared, at least in part, from a material having a surface that has pores, perforations or apertures, or the like; such as a screen, mesh or mesh-like material. In such an embodiment, the shorter bundle segment 127 of the elongated pile sub-assembly may be secured to the fabric mesh, and this may be accomplished by arranging to have the filament segments in the shorter bundle segments penetrate the mesh-like material. The pile covered fabric is then attached to the core. In other embodiments, however, the shorter bundle segment of the elongated pile sub-assembly may be secured to the surface of the core; or the elongated pile sub-assembly may be secured to the core by a bond between the core and the support beam, or a bond between the core and portions, or all, of both the shorter bundle segment and the support beam. In these embodiments, the shorter filament segments may become the point of contact for the application of adhesive between the substrate and the elongated pile sub-assembly, forming an adhesive bond between the substrate and the shorter filament segments, or the shorter filament segments may be the location of, and be contacted with, a zone of polymer flow. The shorter filament segments act as roots in these embodiments, ensuring a solid bond between the elongated pile sub-assembly and the substrate.

[0098] Referring to FIG. 12, another embodiment of the present invention is shown in which elongated pile sub-assemblies 424, 426, 428, 430 are secured to a backing tape 440 by means of hot melt adhesives at the interface of the tape and the shorter bundle segment and/or the support beam of each elongated pile sub-assembly. When the elongated pile assembly is spirally wrapped around a core 442 (FIG. 14), as described in U.S. Pat. No. 5,547,732, the tape 440 has abutting or adjacent wraps on which the elongated pile sub-assemblies from opposite sides of the tape are adjacent to each other, i.e. such that, after one flight or wrap of the tape, elongated pile sub-assembly 424 is adjacent to elongated pile sub-assembly 430. (See U.S. Pat. No. 5,547,732). FIG. 13 shows the bonding of the short segment fibers to the support fabric without the act of adhesives, such as when ultrasonic energy is used.

[0099] Other uses for an elongated pile sub-assembly, according to the present invention, are to make a pile surface structure. A pile/brush surface structure is useful for further fabrication into a variety of articles such as a wall or floor covering, or an airplane or automotive component for a motor vehicle such as a door panel, a headliner, a floor or trunk mat, or seat upholstery. FIG. 15 shows a method to make a pile surface structure such as carpet using the pile sub-assembly of the invention. A drum 78 is set up for rotation with a backing material 80 attached, for instance, by clamping the ends 82 and 84 of the backing in a slot 86 in the drum. The surface 87 of the backing facing outward would be coated with an adhesive coating, such as a thermoplastic adhesive. An assembly 88 is set to traverse parallel to the rotational axis of the drum and carry an elongated pile sub-assembly guide 90 and a hot glue applicator nozzle 92 to position and meter a thermoplastic or thermoset adhesive just before or coincident with contact with the elongated pile sub-assembly and on its center line. Other ways of heating may include a hot air jet, radiant heater, or flame. The elongated pile sub-assembly 45 could be supplied from a reel 94 or directly from a mandrel.

[0100] With continued reference to FIG. 15, as drum 80 is rotated clockwise, the elongated pile sub-assembly is pulled through guide 90, and pressed against the applied adhesive on the fabric surface 87 of backing 80. The elongated pile sub-assembly contacts the hot adhesive and is bonded to the backing. The assembly 88 is synchronized to traverse along the drum surface and lays down a spiral array of the elongated pile sub-assembly to the backing surface, with adjacent runs of the spiral closely spaced such that the just-applied elongated pile sub-assembly lies close to the previously-applied elongated pile sub-assembly in the spiral array to define a pile surface structure. After the elongated pile sub-assembly has been traversed the axial length of the drum surface, the winding is stopped, and the assembly of the elongated pile sub-assembly and backing is cut along the drum axis, such as at line 96 where the two backing ends come together at slot 86. In the embodiment shown, only the elongated pile sub-assembly need be cut at 96 and the backing ends released to remove the pile structure assembly. The pile structure assembly can then be removed from the drum and laid flat to form a pile surface structure or carpet.

[0101] The carpet product made by this method has the feature that the adjacent rows of elongated pile sub-assemblies come from different elongated portions of the same elongated pile sub-assembly which eliminates yarn lot variations within the carpet. For instance, a carpet having about 3.3 oz/ft² of yarn can be produced by first making an elongated pile sub-assembly from 2350 denier, two strands, ply twisted yarn bonded along the beam at 30 wraps/inch and a inch tuft length, and then mounting the pile sub-assembly on the backing at a pitch of 5 pile sub-assemblies/inch.

[0102] In variations of the method, and the product resulting from the method, shown above, the substrate backing may be selected from woven or spun-bonded materials. The selection of fabrics such as Sontara by E. I. DuPont de Nemours, Reemay by Reemay Incorporated and Cerex from Cerex Advanced Fabrics are particularly useful since they are made of polymeric material, offered in various weights and density, and can be used with the various methods for attaching rooted tuftstrings to them. Although natural fiber fabrics can be used they are limited to the use of adhesives to bond the rooted tuftstrings to them. An elongated pile sub-assembly may be secured to a backing substrate to make a pile surface structure by selecting one of an adhesive, thermal bonding or solvent bonding. An elongated pile sub-assembly may be secured to a backing substrate by use of the support beam and/or the shorter bundle segment, on or beneath the surface of the backing substrate, in the same manner as employed for brush construction. Although the use of adhesive, thermal or solvent bonding means may be preferred, an elongated pile sub-assembly may alternatively be secured to a backing substrate by conventional stitching and/or a hook and loop attachment system.

[0103] Alternatively, the rooted tuftstrings can be attached to sheets of polymer with relatively solid surfaces such as sheets made of epoxy resins, thermosets, thermoplastics, wood, and even metal. (Some of these methods of attaching require the use of adhesives.) As described above with respect to a brush, an alternative to wrapping the elongated pile sub-assemblies spirally, as shown in FIG. 15, is to make a pile surface structure by creating an array in which one or more elongated pile sub-assemblies are, for example, in parallel alignment to each other and brought into contact with a bonding surface of a backing substrate.

[0104] Another method of securing more than one elongated pile sub-assembly to a backing substrate is shown by the guide assemblies of FIGS. 16 and 17. Unlike the rotating drum process described above, these guide assemblies are capable of continuous operation and do not have to be stopped to remove the carpet of elongated pile articles. FIG. 16 shows a schematic view of a guide for the elongated pile sub-assembly 125 to create a pile fabric or article. This flat guide assembly 90 is better suited for relatively stiff substrates that would resist bending or would otherwise take on a set from the curved guide 91 of FIG. 17.

[0105] In FIG. 16, the long flat bottom surface is positioned with a suitable gap between and parallel to (not shown) the substrate and the guide assembly 90. The gap 310 is determined by one or more variables which include the length of the short fiber segments 127, the vertical dimension 315 of the beam, the depth of the beam guide groove 320 and the depth of the adhesive. The beam dimension 315 must not be able to pass through the spacing of 325. The gap 325 loosely confines the portion of the long bundle segment proximal to the beam 119 together with gap 328 which loosely confines the beam to correctly position the short and long fibers normal to the substrate. Generally speaking the spacing 325 is greater than 20% of the beam width 322 and more preferably between 20% and 50% of the beam width. A typical set-up would position the guide 90 with an elongated pile sub-assembly 125 threaded into the guide 90 over the flat substrate with a minimal gap between the bottom surface of the beam and the substrate to substantially splay the short segment filaments 127 without causing binding of the elongated pile sub-assembly 125 as it passes through the slot 97 of the guide assembly 90.

[0106] The rooted tuftstring pile articles are continuously supplied from one or more rooted tuftstring machines or from an inventory on spools. The elongated pile sub-assemblies are directed by rolls and guide pins (not shown) into the grooves of the guide with the short bundled end extending outward therefrom. The guide mechanism guides a plurality of individual short bundle segments of elongated pile sub-assemblies into contact with the preferably continuously fed backing substrate. An adhesive material such as a thermoset or thermoplastic adhesive is applied to the surface of the substrate just prior to passing under the guide assembly. Ideally, the linear rate of the process and the heat capacity of the adhesive is adequate to achieve good wetting and encapsulation of the short fiber segments prior to bonding with the substrate. The adhesive is cooled as it passes under the guide assembly such that at the exit of the guide, the rooted tuftstrings are unable to reposition themselves.

[0107] Another process embodiment of the present invention for the flat guide of FIG. 16 uses a thermoplastic polymer melt delivery system and die assembly to cast or to form the substrate on the exposed surface of the guide assembly 90 having exposed portions of elongated pile sub-assemblies extending therefrom. In this case, the guide is inverted such that the short fiber bundles extend vertically upward from the guide. A polymer melt delivery system drops a curtain of polymer melt onto the top guide surface. A band or strip of material such as Kapton or Teflon may be used as a barrier to protect otherwise exposed metal surfaces from the polymer melt when the polymer melt has a tendency to adhere to the metal. The guide surface is sufficiently cool and causes a rapid freezing of the polymer melt with the short segment fibers encapsulated therein. The elongated pile articles assist in transporting the melt from the plate and cooling of the thermoplastic polymer. Since the elongated pile articles are sufficiently strong and not excessively heated, the sheet of polymer will be adequately supported by the elongated pile articles after it leaves the guide and continues to cool.

[0108] Another process embodiment of the present invention is shown schematically in FIG. 17. The short segment fibers 127 of the elongated pile sub-assembly 125 face toward the bonding element (e.g. adhesive applicators 95) as the elongated pile sub-assembly are feed through the guide 91. The short bundle segments of the elongated pile sub-assembly preferably wipe the adhesive from the applicator end and the elongated pile sub-assembly continuously wipes the guide surface to avoid a large build up of adhesive in the guide as the elongated pile sub-assembly is feed through the guide. The fabric backing 99 is fed in concert with the tuftstring for bonding by one or more of the adhesive applicators 95 forming a pile covered fabric 199. Although two applicators are shown in this embodiment, one may be sufficient. If one adhesive applicator 95 is used the adhesive can be applied to the short bundle segments 127 just prior to their contact with the substrate 99 or alternatively, directly to the fabric backing or substrate 99. The number of applicators used may also be increased to more than two in this embodiment if required.

[0109] This process embodiment is well suited for substrates that are flexible enough to conform to the curvature of a roll 91. The low thermal conductivity of most substrates allow a hot melt adhesive to be applied directly to the substrate with good heat retention and high flow properties upon contact with the short bundle segments of the rooted elongated pile article. For some substrates, some heating of the roll 93 may be required to maintain fluidity of the adhesive until time for the desired bonding. This heating of the roll 93 may be needed particularly when the substrates are extremely thin.

[0110] As with the guide assembly of FIG. 16, the guide device of FIG. 17 must be set up properly for optimum performance. The curvature of the guide assembly 91 is designed to be concentric over the arc length with the roll surface. Again the distance between the roll 93 rotating in the direction of arrow 98 and the guide 91 is established to ensure the short segment fibers splay and/or penetrate properly when pressed into the substrate as shown in FIGS. 2A4.

[0111] In both FIGS. 16 and 17, the guide assembly can be mounted onto a mechanism which permits adjustment of the guide vertically and if desired, horizontally. This is advantageous since the guide can be retracted for cleaning, thread-up or other preparatory/maintenance activities. Small incremental adjustments in positioning can be accomplished while operating the process.

[0112] FIGS. 18A and 18B show ultrasonic bonding of the rooted tuftstring 125 to the substrate 115 in the present invention. The ultrasonic horns 340, 345 vibrates in the direction shown by arrows 342, 343, respectively, with anvils 350,355, respectively providing a rigid support for the ultrasonic horns. A force 346, 347 presses the substrate 115 and the short segment fibers into contact with each other while vibrational energy is transmitted from the energized horn. The vibrational energy generates frictional heating at the interface causing surface melting of at least one of the short segment fibers 129, the beam 119, and the substrate 115, creating a polymer flow zone that will bond the elongated pile sub-assembly to the substrate. FIGS. 18A and 18B show the anvils 350, 355 and the horns 340, 345, respectively, functioning as elongated pile sub-assembly guides, respectively.

[0113] It is, therefore, apparent that there has been provided in accordance with the present invention, an elongated pile sub-assembly having roots, guide device and products made from the elongated pile sub-assemblies, that fully satisfies the aims and advantages hereinbefore set forth. While this invention has been described in conjunction with a specific embodiment thereof, it is evident that alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.