Single and double end modular yarn feed enabling half gauge shifting using double end yarn drives   

Abstract: A tufting machine is configured with yarn drives having two spaced apart yarn bearing surfaces each substantially wrapped with a yarn and may have only half the needles and yarn drives customarily employed, with the needles being shifted to cover two gauge positions, thereby providing single and yarn control with reduced capital cost.

The present application claims priority to U.S. Provisional Application Ser. No. 61/453,963 filed Mar. 18, 2011.

FIELD OF THE INVENTION

The invention relates to yarn feeds enabling the control of individual yarns and modularization of yarn feed attachments for tufting machines, and their advantageous arrangements and operation.

BACKGROUND OF THE INVENTION

In the field of tufting, the ability to control individual yarns and small pluralities of yarns has been a constant objective over time, yarn feeds have evolved from roll attachments, to scroll attachments, and to servo motor driven scroll attachments and finally even to a single end servo motor driven yarn feed attachments. As hundred of yarns are fed from a yarn supply such as an array of yarn spindles in a creel, the plurality of yarns may form a yarn sheet that blocks a machine operator from the observation or manipulation of the portion of a tufting machine located opposite of the yarn sheet. On early yarn feed attachments, such as roll attachments, the number of moving parts that required attention were of a manageable numerosity and were principally located at either side of the tufting machine, to one side or the other of any yarn sheet. However, as servo-scroll attachments and single-end servo-scroll attachments were developed, typified by those shown in U.S. Pat. Nos. 6,244,203 and 6,283,053, yarns passing through guides both leading from the yarn supply to yarn drive motors and from yarn drive motors to needles of tufting machine combined to create sheets or ribbons of yarns.

These groups of yarns impeded access to the many moving parts associated with dozens if not hundreds of independently controlled servo motors, yarn drive wheels, and associated gears, controllers, and other parts. Having to reach through these yarn sheets or ribbons in order to maintain, repair and replace parts was not desirable. Accordingly, in U.S. Pat. No. 6,213,036, re-issued as U.S. RE40,194, a scheme was devised where yarns were fed internal of the yarn feed attachment through tubes and then outward around a servo motor driven yarn drive wheel with a biased pressure roller to maintain a good grip on the yarn with the drive wheel, and back into a second yarn guide and within the yarn feed assembly leading the yarn to a position relatively close to the needles of the tufting machine. In this fashion, the yarn was brought to a yarn feed motor and taken from the yarn feed motor to the needles largely in an area behind the yard feed motor and drive wheel. As a result, no yarn sheet is created and any repairs needed on the motor or yarn drive wheel or yarn pressure apparatus could be performed without the necessity of working through a yarn sheet.

A slight modification of this yarn supply scheme was disclosed in U.S. Pat. No. 6,807,917 where yarns were fed into a yarn feed attachment through yarn guide tubes fed within the attachment behind servo motor and drive wheel assemblies, then outward and wrapped around a drive wheel and pressure or pinching assembly, and finally conveyed in a yarn sheet segment or ribbon normal to the servo motors onward to the needles. In this fashion, substantial openings between normal yarn ribbons allowed for accessibility to motors and yarn drive wheel and pressure apparatus.

Even the advances of U.S. Pat. Nos. RE40,194 and 6,807,917 leave room for improvement. In particular, the operation of a single yarn feed roll grasping yarn with the assistance of a biased pincher mechanism does not reliably and adequately control all types of yarns, especially for precise and significant variations in yarn feeding increments. Furthermore, when yarns are fed through tube assemblies to the proximity of a yarn drive wheel on a replaceable servo motor assembly, the replacement of that assembly generally requires the cutting of the yarn, the rethreading of the yarn through the replacement assembly, and the splicing of the cut yarn ends before tufting can be resumed. Finally, the numerous yarn tubes behind the yarn drive motors and numerous electrical connections that need to be made connecting drive motors to motor controllers and pattern controllers can result in a crowded yarn feed apparatus that is difficult to service and maintain.

Furthermore, while the control of individual yarns is highly desirable for the production of unique fabric designs, the expense of yarn feed attachments with approximately 1500 separately controlled motorized yarn drives can be prohibitively expensive. In many instances it is considered preferable by carpet manufacturers to make a smaller investment in a tufting machine, even if that machine will not operate as quickly as a more expensive machine.

Accordingly, a need exists for additional improvements in the servo driven yarn feed apparatus adapted for the feeding of ones and small pluralities of yarns to the needles of a tufting machine and for methods of operating servo driven yarn feed apparatus that can reduce the capital costs associated with a broadloom tufting machine having individual yarn feed control.

SUMMARY

The present invention is directed to overcoming some of the aforementioned shortcomings and other objectives and in various embodiments and operations may include feeding the yarns from a yarn supply into a yarn feed attachment having an array of yarn supply tubes to carry yarns from a rear position forward and substantially around two drive wheels thereby supplying yarns in precise increments to needles without the use of a pressure or pincher apparatus and optionally configuring the needles at twice the gauge of the loopers and shifting the yarns to fill two half gauge steps before advancing the backing fabric (or advancing the backing fabric at about half speed), and preferably feeding from a yarn supply into a yarn feed attachment having an array of yarn supply tubes to bring yarns from a rearward position forward and about a yarn drive wheel thereby supplying yarns in precise increments to needles without the use of a pressure or pincher apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

The particular features and advantages of the invention as well as other objects will become apparent from the following description taken in connection with the companying drawings in which:

FIG. 1 is a representation of a prior art servo scroll type yarn feed attachment showing the yarn sheet that blocks the operator from directly accessory yarn drive wheels and servo motors.

FIG. 2 is a schematic diagram of a tufting machine configured to use a computer controlled yarn feed;

FIG. 3 is an exploded view of a four-unit yarn feed module.

FIG. 4 is a rack holding four of the four-unit modules of FIG. 3.

FIG. 5 is a chassis holding two of the racks of FIG. 4.

FIG. 6 is an assembled chassis of three racks of yarn feed modules showing the threading of the yarns.

FIG. 7 is a top plan of the needle and looper assembly adapted to practice the present invention.

FIG. 8 is a schematic depiction of the back stitch created by a thread up of red green blue and yellow yarns on sequential needles.

Referring to the drawings in more detail, FIG. 1 discloses a multiple needle tufting machine 10 upon the front of which is mounted a pattern control yarn feed attachment 11 in accordance with U.S. Pat. No. 6,550,407. The machine 10 includes a housing 12 and a bed frame 13 upon which is mounted a needle plate, not shown, for supporting a base fabric adapted to be moved through the machine 10 from front to rear in the direction of the arrow 14 by front and rear fabric rollers. The bed frame 13 is in turn mounted on the base 15 of the tufting machine 10.

A main drive motor drives a rotary main drive shaft 17 mounted in the head 18 of the tufting machine. Drive shaft 17 in turn causes push rods 19 to move reciprocally toward and away from the base fabric. This causes needle bar 20 to move in a similar fashion. Needle bar 20 supports a plurality of preferably uniformly spaced needles 21 aligned transversely to the fabric feed direction 14.

In operation, yarns 22 are fed through tension bars 23, into the pattern control yarn feed device 11. After exiting the yarn feed device 11, yarns 22 are guided in a conventional manner through yarn puller rollers 24, and yarn guides 25 to needles 21. A looper mechanism, not shown, in the base 15 of the machine 10 acts in synchronized cooperation with the needles 21 to seize loops of yarn 22 and form cut or loop pile tufts, or both, on the bottom surface of the base fabric in well known fashions.

In order to form a variety of yarn pile heights, the pattern controlled yarn feed mechanism 11 incorporates a plurality of yarn feed rolls adapted to be independently driven at different speeds and is attached between the tensioning bars 23 and the yarn puller rollers 24.

An array of yarn drives 35 is assembled on an arching support bar 26 extending across the front of the tufting machine 10 and providing opposing vertical mounting surfaces on each of its sides and an upward facing top surface. On the opposing side-facing surfaces are preferably mounted a total of twenty servo motors 31 and driven yarn feed rolls 39, ten on each side.

As shown in FIG. 1, the arching support bar 26 accommodates the wiring bundle 53 from the motors which facilitates the wiring of the motors.

Each yarn drive 35 consists of a yarn feed roll 39 and a servo motor 31. The yarns 22 are directed by yarn guide plates 27 and other conventional designs so that the yarn 22 are supplied from a yarn supply to and around a yarn feed roll 39 and on to the needles 21. Yarn guide posts may protrude from the yarn guide plates 27 in the general direction of the yarn feed, and help ensure the proper placement of two or more yarns 22 on yarn feed rolls 39.

It can be seen that the supplying of twenty or forty yarns 22 through yarn guide plates 27 creates a yarn barrier sheet 28 both as yarns are directed to the yarn drives 35 and onward from yarn drives 35 to needles 21. Accordingly, it has been desirable in this type of configuration to allow the arching support base 26 to pivot downward to facilitate service and repair from the sides. When the arching support bar 26 is pivoted downward, side access is provided to the vertical mounting surfaces, that otherwise would be obstructed by adjacent support bars.

The tufting machine 110 disclosed in FIG. 2 includes a rotary needle shift or main drive shaft 111 driven by stitch drive mechanism 112 from a drive motor 113 or other conventional means. Rotary eccentric mechanism 115 mounted upon rotary needle shaft 111 are adapted to reciprocally move the vertical push rod 116 for vertically and reciprocally moving the needle bar slide holder 117 and needle bar 118. The needle bar 118 supports a plurality of uniformly spaced tufting needles 120 in a longitudinal row, or staggered longitudinal rows, extending transversally of the feeding direction of the backing fabric or material 122. The backing fabric 122 is moved longitudinally through the tufting machine 110 by the backing fabric feed mechanism 123 which may be independently driven, or driven from the main drive motor 113, and across a backing fabric support with needle plate and needle plate fingers.

Yarns 125 are fed from the yarn supply 126 to the respective needles 120. As each needle 120 carries a yarn 125 through the backing fabric 122, a hook is reciprocally driven by the looper drive 129 to cross each corresponding needle 120 and hold the corresponding end 125 to form loops. Cut pile tufts are formed by cutting the loops with knives.

The needle bar shifting apparatus 132 is designed to laterally or transversely shift the needle bar 118 relative to the needle bar holder 117 a predetermined transverse distance equal to the needle gauge or multiple of the needle gauge, and in either transverse direction from its normal central position, relative to the backing fabric 122, and for each stitch of the needles 120. Shifting apparatus 132 may be any suitable mechanism, operating by hydraulics, drive screw, or cams for instance, and the crank shifter of application Ser. No. 12/716,244, which is incorporated herein, being particularly suitable.

In order to generate input encoder signals for the needle bar shifting apparatus 132 corresponding to each stitch of the needles 120, an encoder 134 may be mounted upon a stub shaft 135, or in another suitable location, and communicate positional information from which the tufting machine controller can determine the position of the needles in the tufting cycle. Alternatively, drive motors may use commutators to indicate the motor positions from which the positions of the associated driven components may be extrapolated by the controller.

FIG. 3 is an exploded view of a four unit yarn feed module adapted for feeding single ends of yarn. The modules include circuit boards 2A receiving instructions for operation of associated motors from master controller, motors 12A, faceplate 1A, dowel pin 16A, drive gears 5A and 6A, shoulder bolts 7A and 8A screws 11A, 12A, 14 A, 13A, and 15A, pinion gear 4A thread guide 10A and guide support bracket 9A. FIG. 4 shows a rack holding four of the four unit modules of FIG. 3, including a front mount plate 1B, a bottom plate 2B, and a top plate 3B. FIG. 5 is a chassis holding two of the racks of FIG. 4, showing an inlet faceplate 16C, yarn tubes 18C, side plates 11C and 12C, back plate 15C, and yarn guides 13C and 14C. FIG. 6 shows an assembled chassis of three racks of yarn feed modules illustrating the threading of yarns through guide tubes and yarn guides.

Yarns are fed into openings in faceplate 16C from a yarn supply such as a creel or yarn beams, and through yarn tubes 18C around to the rear of the module and then forward to emerge from faceplate 1A in proximity to the drive gears. Yarn guides, preferably of ceramic material, may direct the one or two yarns supplied by yarn tubes 18C to wrap substantially around the yarn surface of first drive gear 5A, preferably contacting the yarn bearing surface of the gear around more than half its circumference, thereby making contact through an arc of over 180°. Then the yarn is directed in an opposite direction around a substantial portion of the yarn bearing circumference of the second yarn drive gear 6A, again through an arc of over 180°, thereby making an “S” shape around the drive gears. The yarn then is directed by another yarn guide downward to openings or notches in a multiple yarn guide, such as guide plates 13C, 14C.

By arranging openings in the yarn guide plates extending in a row or rows outward from the transverse direction of the tufting machine, the yarns do not form a sheet blocking access to the drive gears and yarn tubes, but instead form relatively small perpendicular ribbons that are relatively easy to work around. It can be seen that as racks are stacked in a chassis, the yarn guide plate on the lower rack must accommodate its yarns and the yarns from each rack above.

Surprisingly, with the yarns substantially wrapped around the two drive gear surfaces in an “S” configuration, there is sufficient grip on the yarn that it is not necessary to pinch the yarn between the yarn surfaces, especially when the surfaces have a grit or other high friction surface. This is most advantageous because pinching yarns between surfaces causes those surfaces to wear faster and often in a very localized area, resulting in the need for more frequent maintenance and replacement of parts. Pinching yarns also can cause problems in the regular supply of yarn if the yarns have irregularities such as knots or severe crimping, as these irregularities may cause breaks during the supplying of yarns for tufting. To help insure proper feeding of yarn with the spaced apart yarn feeding surfaces of the illustrated design, the second drive gear can be rotated at a slightly faster rate or can be provided with a slightly greater circumference so that no loose yarn develops between the gears. While the yarn bearing surfaces of this design still will require replacement, the parts will have improved operating lives relative to pinched rollers. Furthermore, the parts will be readily accessible for adjustment or replacement between the perpendicular ribbons of yarns.

In order to achieve capital savings, the tufting machine may configured with only half the number of needles, and associated yarn drive units that would usually be required. Thus on a one-tenth gauge machine, there usually would be 10 needles per inch, or about 1440 needles on a 12 foot wide machine. In order to practice the invention, the machine is still equipped with loopers on one-tenth gauge, however needles are spaced at one-fifth gauge, so that only about 720 needles are required for the machine. This configuration is depicted in FIG. 7 with needle plate 225 having rearward extending fingers 226, over loopers 231 on gage and needles 214 spaced at double gauge. In this configuration, only 720 yarn drives are required to provide individual yarn control.

FIG. 8 illustrates the operation of this tufting machine configuration. The sequential needles A, B, C, D are threaded sequentially with red, green, blue, and yellow yarns. It will be understood that any suitable color palette can be chosen to create a carpet with the desired hues. The needles 214, corresponding to A, B, C, and D, are spaced at one-fifth inch intervals. On each cycle of the tufting, the needles are shifted one-tenth of an inch to the adjacent looper 213. The backing fabric is fed at only half the customary speed because each needle is has to cover two gauge positions. In this fashion, a tufting machine is able to provide single end yarn control with only half the number of yarn drives traditionally required. The individual yarns are fed at relatively high or low speeds so that the respective tufts will be visible, partially visible, or buried as is well known in the single end tufting art. It will also be understood that the shifting pattern may be more complex when desired for patterning purposes, but the principal of using one needle to sew two laterally spaced stitches in the longitudinal length of one row can still be implemented with proper pattern controls.

It will be seen that in the single and configuration described, no tubing is required to distribute yarns across the tufting machine. The yarns are simply fed to adjacent needles. The same technique may be utilized in connection with a servo-scroll in order to effectively double the width of each repeat of the pattern. Although it is necessary to have a special tube bank when employee in this technique with a servo-scroll yarn feed, typified by that disclosed in U.S. Pat. No. 6,244,203.

All publications, patent, and patent documents mentioned herein are incorporated by reference herein as though individually incorporated by reference. Although preferred embodiments of the present invention have been disclosed in detail herein, it will be understood that various substitutions and modifications may be made to the disclosed embodiment described herein without departing from the scope and spirit of the present invention as recited in the appended claims.