Abstract:
A puller roller system for tufting machines having a series of intermeshed puller rolls for tensioning a series of yarns to one or more needles of the tufting machine. According to one embodiment of the invention, the puller roller system includes at least one toothed, driven puller roll in rotating and intermeshing relationship with at least two toothed, floating puller rolls. The spacing between the puller rolls is sufficient to securely engage and tension the yarns to the needles without pinching the yarn.

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to machinery and systems for tufting carpets. In particular, the present invention relates to an improved puller roll assembly for a tufting machine. 
     BACKGROUND OF THE INVENTION 
     In addition to yarn feed systems and/or pattern yarn feed attachments, tufting machines generally include pairs of toothed puller rolls that tension yarns from the yarn feed mechanism or attachments to needles of the tufting machines. Such puller roll systems typically consist of a drive roll and an idler roll that operate in a rotating, intermeshing relationship. As the rolls rotate, the yarns are engaged and pinched between the teeth of the puller rolls, which engage in an intermeshing fashion, defining a yarn pinch area between the rolls. The yarns are engaged and pinched between the teeth of the puller rolls as they pass through the pinch area, such that the rotation of the rolls causes the yarns to be tensioned between the rolls for feeding to the needles. 
     With such traditional puller roll systems as described above, there generally is only a limited area or point of contact at which the yarns are pinched and pulled between the puller rolls. As a result of such limited contact of the yarns with the rolls, the yarns therefore must be tightly engaged or pinched between the teeth of the rolls to try to limit slippage and to thus provide consistent tensioning and feeding of the yarns through the system. As a result, the spacing and intermeshing of the rolls is critical for achieving a uniform, substantially constant flow of the yarns through the rolls without significant slippage or misfeeding of the yarns. As a consequence, it generally has been necessary to monitor and make frequent adjustments to the positions and spacings between the rolls to compensate for the feeding of different sizes or thicknesses of yarns. Such adjustments typically are made manually through the use of adjustment shims, which manual adjustments often are not sufficiently precise, and thus can necessitate additional adjustments. Furthermore, the pinching of the yarns by the rolls can damage or cause breaking of the yarns if the spacing or pinching is too tight or can cause jamming of the rolls if knots are passed therebetween, resulting in misfeeding of the yarns. 
     There is, therefore, a need for an improved puller roll system that can securely and consistently tension yarns of various sizes to the needles of a tufting machine without requiring continuous adjustment of the puller rolls. 
     SUMMARY OF THE INVENTION 
     Briefly described, the present invention relates to an improved puller roll system for feeding yarns to the needles of a tufting machine. According to one embodiment of the invention, the puller roll system includes at least one driven puller roll and a pair of floating puller rolls. The driven and floating puller rolls each include radially projecting teeth, and the floating puller rolls are mounted in an intermeshing relationship with the driven puller roll so that the floating puller rolls are rotated with the rotation of the driven puller roll. A yarn engagement path is defined between the driven puller roll and the floating puller rolls along which the yams are received and are passed in a winding, substantially serpentine path. The puller rolls engage the yarns along the engagement path at multiple points or areas of contact with the yarns being engaged between both of the floating puller rolls and the driven puller roll and with the yams being wrapped about a portion or wrap area of the driven puller roll. 
     As a result, the amount and/or area of contact between the yarns and the puller rolls is substantially increased so that the yarns can be securely tensioned through the engagement path towards the needles without requiring the yarns to be pinched tightly between the puller rolls. In addition, due to the increased areas and amount of contact along which the puller rolls engage the yams, the puller roll system of the present invention can be used to tension various types and sizes of yarns without requiring frequent adjustments of the positions of or spacings between the puller rolls. Consequently, the puller roll system of the present invention enables looser spacing between the puller rolls, with the spacings being set at a distance sufficient to enable a minimum engagement and contact between the yarns and the teeth of the puller rolls sufficient to tension the yarns without the yarns necessarily being tightly pinched between the rolls, which reduces the likelihood that the yarns will be damaged by the puller rolls. 
     Various object features and advantages of the present invention will become apparent to those of skill in the art upon reading the following detailed description in view of the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view schematically illustrating a tufting machine including a puller roll system according to one embodiment of the present invention. 
     FIG. 2 shows a cut-away, back side view of the puller roll system of the present invention. 
     FIG. 3 is an end view, with portions removed, of the puller roll system of FIG.  1 . 
     FIG. 4 shows a cross-sectional view of the puller roll system of the present invention taken along section A—A of FIG.  2 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings in which like numerals indicate like parts throughout the several views, FIG. 1 discloses a tufting machine  10  including a frame  11  and a reciprocable needle bar  12  supporting a plurality of spaced needles  13  disposed therealong. The needles  13  are reciprocated vertically through a backing fabric or material  14 , as the backing fabric  14  is moved through the machine  10  in a direction of feed indicated by arrow F. Each of the needles carries a yarn  16  and cooperates with a corresponding looper  17  so as to form a series of loops or tufts of yarn in the backing fabric  14  as each needle penetrates the backing fabric, as indicated in FIG.  1 . The tufting machine  10  further includes a yarn feed mechanism  20  that is mounted on and supported by the tufting machine frame and includes a series of yarn feed rolls  21 ,  22  that feed the yarns  16  at prescribed or programmed rates of feed in accordance with programmed pattern instructions to the puller roll assembly  25  of the present invention for the feeding of the yarns  16  to the individual needles  13  to form or tuft desired patterns in the backing fabric passing beneath the needles  13 . 
     It will be understood that the yarn feed mechanism  20  can include any type of known pattern yarn feed mechanisms, including computer controlled, motor driven yarn feed rolls or other conventional yarn feed/drive mechanisms including roll and scroll type pattern attachments that control the feeding of all the yarns across the width of the tufting machine to their respective needles. Other known types of yarn feed mechanisms that can be used include multiple feed rolls for controlling the feeding of specific sets or repeats of yarns to selected needles, and further including the use of individual yarn feed rolls for controlling the feeding of individual yarns to a respective needle. For example, U.S. Pat. Nos. 6,009,818 and 5,983,815 disclose pattern yarn feed devices for controlling the feeding and distribution of the yams, and U.S. Pat. No. 5,979,344 discloses a precision drive system for driving various operative elements of the tufting machine, which systems can be used with the present invention and are incorporated herein by reference. 
     As shown in FIG. 1, the puller roll assembly  25  of the present invention is mounted to the tufting machine frame  11  between the yarn feed mechanism and the needles and receives and pulls the yarns  16  from the yarn feed mechanism  20  and feeds the yarns  16  to needles  13 . The puller roll assembly  25  (FIG. 2) generally includes a pair of spaced bearings or mounting brackets  26  and  27  that are mounted to the tufting machine frame as conventionally known. The mounting brackets or bearings generally are substantially “U” or “C” shaped brackets or plates, typically formed from a metal or other similar material. Each mounting bracket or bearing generally includes a forward or proximal bearing member or portion  28  that is mounted to the tufting machine frame by a series of spaced machine mounts  29 (FIGS.  3  and  4 ), such as bolts, screws or other similar kinds of fasteners, and a rearward, distal bearing member or portion  31  that generally is adjustably mounted with respect to its forward bearing member  28 , in a position spaced from the forward, proximal bearing member or portion. 
     As indicated in FIG. 3, the distal bearing member  31  of each bearing or mounting bracket is adjustably mounted to its proximal bearing member  28  by fasteners, shown in dashed lines  32 , such as bolts, screws, pins or other similar kinds of fasteners or adjustable mounting mechanisms. The fasteners  32  generally each include a head  33  that typically is countersunk into the distal bearing members  31  and a shank portion that extends through its distal bearing member  31  and is received in and engages a corresponding recess or aperture  36  formed in the proximal bearing member  28  therefor. 
     As indicated in FIGS. 2-4, the mounting brackets  26  and  27  rotatably support a series of intermeshing puller rolls  40 ,  41 , and  42  at each end thereof. Each of the puller rolls  40 - 42  generally is an elongated roll or gear having a series of radialy projecting teeth  40 A,  41 A, and  42 A, respectively, which teeth intermesh and engage the yarns  16  (FIG. 4) therebetween as the rolls are rotated. A first one of the puller rolls  40  generally is mounted to the proximal bearing members  28  of the mounting brackets  26  and  27  and is a power driven puller roll, generally driven by a motor, such as indicated by  43  in FIG. 1, in a known or conventional manner. The remaining or second and third puller rolls  41  and  42  (FIGS. 3 and 4) generally are idler or floating puller rolls, each rotatably mounted at their ends to the distal bearing members  31  of mounting brackets  26  and  27  (FIG.  2 ). The floating puller rolls  41  and  42  generally are rotated with the rotation of the drive roll  40 , as the teeth  41 A and  42 A of puller rolls  41  and  42  are engaged and intermesh with the teeth  40 A of the driven puller roll  40 . This engagement between the teeth of the floating puller roll and the driven puller roll creates or defines multiple areas of contact  44  and  46  between the teeth of puller rolls  40  and  41 , and between puller rolls  40  and  42 , respectively. 
     As illustrated in FIGS. 3 and 4, a yarn engagement path  47  is defined between the rolls and extends from an upper end or entrance  48  of the puller roll assembly  25  to a lower end or exit  49  from which the yarns  16  are passed for feeding to their respective needles in the direction of arrows  50  (FIG.  4 ). As the yarns are passed along the yarn path  47 , they are engaged between the teeth  40 A and  41 A of puller rolls  40  and  41  at a first area of contact  44 , and are further engaged between the intermeshing teeth  40 A and  42 A of puller rolls  40  and  42  at a second area of contact  46  to provide multiple points of engagement and gripping between the teeth of the puller rolls and the yams. In addition, between the areas of contact  44  and  46 , the yarns  16  wrap at least partially around the driven puller roll  40  along a wrap area or region  51  defined along a portion of the circumference or periphery of the driven puller roll  40 , between the areas of contact  44  and  46 , providing still further engagement of the yarns with the driven puller roll. This increased or enhanced engagement of the yarns at multiple points or areas of contact between the teeth of the driven and floating puller rolls  40  and  41  and  42 , respectively, as well as the further engagement of the yarns by the teeth  40 A of driven puller roll  40  at the wrap area  51  along the driven puller roll  40  provides an enhanced positive gripping of the yarns and minimizes risk of slippage of the yarns as it is pulled through or along its yarn engagement path  47  between the puller rolls  40 ,  41 , and  42 . 
     The floating puller rolls generally are positioned in substantially parallel and vertically spaced, aligned positions, each oriented at an angle with respect to the driven puller roll such that the central axis  52  and  53  of each floating puller roll is laterally offset from the central axis  54  of the driven puller roll  40  as shown in FIGS. 3 and 4. As a result, the multiple areas of contact  44  and  46  are provided at spaced locations with the wrap area  51  defined therebetween, and with the yarn path generally extending along a curved path about the drive roll so that the yarns are moved along a somewhat serpentine path through the puller rolls. The positions of the floating puller rolls  41  and  42  with respect to the driven puller roll  40  generally are adjustable by the adjustment or movement of the distal bearing members  31  with respect to their associated proximal bearing members  28  of the mounting brackets  26  and  27  in order to adjust or set the spacing and thus the amount of engagement between the teeth of the puller rolls as needed for feeding a desired range of thicknesses or sizes of yams. Additionally as indicated in FIGS. 3 and 4, shims  56  can further be placed within the gaps  57  between the proximal and distal bearing members  28  and  31  as desired to help secure or fix the spacing of the proximal or distal bearing members and thus the spacing of the driven and floating  40  and  41  and  40  and  42  puller rolls with respect to one another. 
     With the present invention, the floating puller rolls  41  and  42  do not have to be mounted in a tight, pinching engagement with the drive roll  40  so that the yarns  16  (FIG. 4) are tightly engaged and pinched between the teeth of the floating and drive puller rolls avoid slippage and to ensure positive engagement of the yarns by the puller roll assembly of the present invention. Instead, with the puller roll assembly of the present invention, by providing multiple points or areas of contact and an additional at least partial wrapping of the yarns about the periphery of the driven puller roll  40 , the spacings between the puller rolls can be much looser, typically being set at a minimum engagement or spacing so as to enable relatively loose or light contact or engagement of the yarns therebetween with the potential for slippage of the yarns minimized, instead of requiring a very tight, pinching engagement of the yarns between the teeth of the puller rolls as generally is necessary in conventional puller roll assemblies. 
     As a result, with the puller roll assembly of the present invention, the floating and drive puller rolls are spaced sufficiently to maintain a minimum amount of contact between the yams and the intermeshing teeth of the puller rolls, which spacing is sufficient to provide a positive engagement and pulling of the yarns with the risks of slipping being minimized, but without the yarns further having to be tightly engaged and pinched between the puller roll teeth. In addition, by providing multiple areas or zones of contact  44  and  46 , and a wrap area  51  along which the yarns are engaged by the teeth of the drive roll  40 , the floating puller rolls of the present invention generally do not need to be continually adjusted with respect to the drive roll  40 , and, can accommodate the feeding of a variety or range of different size thickness yarns and the passage of knots or other imperfections or obstructions in the yarns passing therethrough without the yarns becoming jammed and/or requiring frequent, precise mechanical adjustment of the positions of the floating puller rolls with respect to the driven puller roll  40 . 
     In the operation of the puller roll assembly  25  of the present invention, a series of yarns  16  (FIG. 1) are fed from the yarn feed mechanism  20  into the upper end  48  (FIG. 4) of the puller roll assembly  25 . The yarns  16  are passed along a yarn path  47  between driven puller roll  40  and floating puller rolls  41  and  42 . The yarns are engaged between the intermeshing teeth  40 A and  41 A of the driven and floating puller rolls  40  and  41 , respectively, at a first area of contact  44 , then are extended or wrapped about a wrap zone or area  51  extending at least partially about the periphery of drive roll  50 , and further are engaged along a second area of contact  46  between the teeth  40 A and  42 A of driven puller roll  40  and floating puller roll  42 , respectively. The intermeshing teeth of the drive and floating puller rolls at the areas or points of contact  44  and  46  tend to lightly engage and pull the yarns at multiple points of contact. In addition, the friction between the yarns and teeth  40 A of driven puller roll  40  along the wrap area  51 , in conjunction with the engagement of the yarns at the areas of contact  44  and  46 , helps the yarns to be pulled along the yarn path  47  through the puller roll assembly  25  without requiring a tight pinching engagement of the yarns by the teeth of the puller rolls. The yarns exit the puller roll assembly at the lower end  49  thereof, and are fed to individual needles  13  (FIG. 1) at a prescribed rate of feed for insertion into the backing fabric  14  passing through the tufting machine. 
     The present invention thus provides a cost effective and reliable puller roll assembly for feeding the yarns to the needles of a tufting machine, which does not require a tight, pinching contact between the teeth of the rolls and yarns to avoid potential slippage of the yarns, and further permits or accommodates the feeding of various size or thickness of yarns without requiring continual or frequent adjustments of the spacing of the puller rolls for effectively and consistently feeding the yarns to the respective needles. It will be understood by those skilled in the art that while the foregoing invention has been disclosed with reference to preferred embodiments or features, various modifications, changes and additions can be made to the foregoing invention without departing from the spirit and scope of the invention as set forth in the following claims.