This invention relates to tufting machines and more particularly to a method and apparatus for employing blocked or segmented needle bars while shifting the lateral position of the backing fabric relative to the needles during tufting in a fashion that can allow for increasing (or decreasing) the density of the pile fabric produced, and further to providing patterning and yarn placement effects in the resulting tufted fabrics.
In the production of tufted fabrics, a plurality of spaced yarn carrying needles extend transversely across the machine and are reciprocated cyclically to penetrate and insert pile into a backing material fed longitudinally beneath the needles. During each penetration of the backing material a row of pile is produced transversely across the backing. Successive penetrations result in longitudinal columns of pile tufts produced by each needle. This basic method of tufting limits the aesthetic appearance of tufted fabrics. Thus, the prior art has developed various procedures for initiating relative lateral movement between the backing material and the needles in order to laterally displace longitudinal rows of stitching and thereby create various pattern effects, to conceal and display selected yarns, to break up the unattractive alignment of the longitudinal rows of tufts, and to reduce the effects of streaking which results from variations in coloration of the yarn.
Another reason for initiating relative lateral movement between the needles and the backing material is to increase the density of the fabric by placing the stitches closer together laterally than the gauge of the machine. It has been most common in broadloom tufting to achieve these slight shifts of the backing relative to stitch location by shifting the needle bar while the needles are within the fabric to move the fabric slightly and thereby increase the density. These needle-offset techniques have been known as “positive stitch placement” and “dual stitch placement”, generally described in U.S. Pat. No. 4,630,558. It would be desirable to have a tufting machine that could utilize backing shifting relative to needle and gauge part positions, or vis-versa, in a fashion that was not constrained by the gauge of the needle bar.
In prior broadloom tufting there has been occasional implementation of “blocked needles” on graphics or double needle bar tufting machines. In some cases, this was the grouping of two adjacent needles on a first needle bar or row of needles, and a single needle (or two adjacent needles) on a second needle bar or row of needles. This arrangement would lead to the two yarns from adjacent needles in the first row always being planted through the backing fabric immediately adjacent, and that pair of yarns being separated by one or two yarns from the second row of needles, from the other yarns tufted by the first row. Such configurations are shown in Card, et al., U.S. Pat. No. 5,499,588 with the needles cooperating with two rows of loopers or with one row of loopers and one row of hooks and cutting knives.
Another example was the operation of graphics loop pile tufting machines by Wellco Carpets in creating patterns in its “Parquet” collection. The needle bars on these graphics machines had alternating blocks or segments of consecutive needles on the front and rear needle bars, extending for about one to two inches. So, in a one-inch block setting on fifth gauge needle bars, the front needle bar would have groups of five consecutive needles between needle positions 1-5, 11-15, 21-25, etc. . . . . The rear needle bar would have groups of five consecutive needles between needle positions 6-10, 16-20, 26-30, etc. . . . . The remaining needle positions were empty. Then as the carpet was tufted, nominally at five stitches per inch, the front needle bar would be operated in a “Positive Stitch Placement” mode according to U.S. Pat. No. 4,630,558 for five penetrations, which would slightly align the yarn tufts differently from stitches made on the rear needle bar that were sewn without Positive Stitch Placement shifting effects. In the second five penetrations, the front needle bar would be sewn without Positive Stitch Placement, and the rear needle bar would be sewn with those effects. The result was a carpet face with one-inch squares of slightly varied texture. The carpet was also made with two-inch squares, and could be made even using tenth gauge needle bars with alternating blocks of about 10-20 needles.
Accordingly, the present invention is directed to a backing shifter for use on broadloom tufting machine that is able to operate in a fashion that permits the shifting of the backing fabric relative to the needles and gauge parts without undo interference and thereby permits shifting not simply in gauge increments, but in a fashion that allows the creation of variable gauge and novel fabrics. The use of blocked needles, or alternating segments of consecutive needles on each of two needle bars allows the tufting machine to create different patterns and to tuft with less backstitch yarn and with only defined areas of over-tufting from front and rear needles.
Particular features and advantages of the present invention will become apparent from the following description when considered in conjunction with the accompanying drawings in which:
Referring now to the drawings in more detail,
Yarns 18 are supplied to the corresponding needles 14 through corresponding apertures in the yarn guide plate 19 from a yarn supply, not shown, such as yarn feed rolls, beams, creels, or other known yarn supply means, preferably passing through pattern yarn feed control 21 though simpler yarn feed arrangements such a roll feeds may be employed. The yarn feed control 21 interfaces with a controller to feed yarns in accordance with pattern information and in synchronization with the needle drive, shifters, yarn seizing/cutting mechanisms and backing fabric feed.
The needle bar 12 may be fixedly mounted to the needle bar carrier 11 or may slide within the needle bar carrier 11 for transverse or lateral shifting movement by appropriate pattern control needle shifter mechanisms, in well-known manners. The backing fabric 35 is supported upon the needle plate 25 having rearward projecting transversely spaced front needle plate fingers 22, the fabric 35 being adopted for longitudinal movement from front-to-rear in a feeding direction, indicated by the arrow 27, through the tufting machine 10. The needle bar may have a single row of gauge spaced needles, as shown, or may be a staggered needle bar with front and rear rows of needles, or may even be two separate needle bars, each with a row of needles.
The needle drive mechanism, not shown, is designed to actuate the push rods 16 to vertically reciprocate the needle bar 12 to cause the needles 14 to simultaneously penetrate the backing fabric 35 far enough to carry the respective yarns 18 through the back-stitch side 44 of backing fabric 35 to form loops on the face 45 thereof. After the loops are formed in this tufting zone, the needles 14 are vertically withdrawn to their elevated, retracted positions. A yarn seizing apparatus 40 in accordance with this illustration includes a plurality of gated hooks 41, there preferably being at least one gated hook 41 for each needle 14.
Each gated hook 41 is provided with a shank received in a corresponding slot in a hook bar 33 in a conventional manner. The gated hooks 41 may have the same transverse spacing or gauge as the needles 14 and are arranged so that the bill of a hook 41 is adapted to cross and engage with each corresponding needle 14 when the needle 14 is in its lower most position. Gated hooks 41 operate to seize the yarn 18 and form a loop therein when the sliding gate is closed by an associated pneumatic cylinder 55, and to shed the loop as the gated hooks 41 are rocked.
The elongated, transverse hook bar 33 and associated pneumatic assembly are mounted on the upper end portion of a C-shaped rocker arm 47. The lower end of the rocker arm 47 is fixed by a clamp bracket 28 to a transverse shaft 49. The upper portion of the rocker arm 47 is connected by a pivot pin 42 to a link bar 48, the opposite end of which is connected to be driven or reciprocally rotated by conventional looper drive. Adapted to cooperate with each hook 41 is a knife 36 supported in a knife holder 37 fixed to knife block 20. The knife blocks 20 are fixed by brackets 39 to the knife shaft 38 adapted to be reciprocally rotated in timed relationship with the driven rocker arm 47 in a conventional manner. Each knife 36 is adapted to cut loops formed by each needle 14 upon the bill of the hook 41 from the yarn 18 when gates are retracted and yarn loops are received on the hooks 41. A preferred gated hook assembly is disclosed in U.S. Pat. No. 7,222,576 which is incorporated herein by reference.
It can be seen in
The reciprocating needle plate fingers of
Turning then to
One feature that has proved helpful in maintaining the backing fabric in an unwrinkled state as it enters the tufting zone is the addition of temple roller assemblies 160 near each edge of the backing fabric. These assemblies contain temple rolls 161 that either by angular orientation as at pivots 162, or backing fabric engaging spike configuration, tend to keep the backing fabric stretched to its full width. Other tentering apparatus may also be used to the same effect.
In
Advantageously, and different from prior usage in broadloom tufting machines, the backing assembly can be precisely shifted for substantial distances, typically on the order of 1 to 2.5 inches in each direction from center. This provides tufting machine with great versatility and allows a quarter gauge tufting machine to simulate an ⅛th gauge tufting machine and provides numerous patterning advantages. Furthermore, an ⅛th gauge tufting machine can very nearly imitate a 1/10th gauge tufting machine, although not all stitches will appear in perfectly aligned rows. By way of example, a ⅛th gauge machine will most commonly tuft at a stitch rate of about 8 stitches per inch, thereby placing 64 stitches in a square inch of backing. A 1/10th gauge machine will most commonly tuft at about 10 stitches per inch with a resulting 100 stitches being placed in a square inch of backing. However, by increasing the stitch rate of a ⅛th gauge tufting machine equipped with backing shifter and reciprocating needle plate to 12.5 stitches per inch, a stitch density of 100 stitches per square inch. In cases where the stich rate is being increased by a multiple of the gauge of the backing shifter and reciprocating needle plate equipped machine, there may be a perfect pattern alignment. In other cases, the stitches may not align in exact longitudinal rows.
The failure to align in exact longitudinal rows may be perceived as an advantage in some tufting applications. For instance, solid color shifting is used when manufacturing solid color carpets to break up any streaks or irregularities in the yarns that might otherwise be noticeable. Residential solid color carpets are sometimes sewn on 5/32nds or 3/16th inch gauge staggered needle bars with two rows of needles. These needle bars require shifts of 0.375 or 0.3125 inches for the streak break-up shifting. With a backing shifter and reciprocating needle plate equipped tufting machine, shifts of as little as 0.10 inches, and perhaps 0.05 inches, could be employed. The smaller shifts permit greater machine speed and require less lateral yarn on the backstitches that is effectively lost to effective use.
In
Smaller segments of needles can be used to create various checkerboard or parquet effects in the fabric, and the capability of shifting of the backing and each or the front and rear needles independently allows for even three inch wide blocks, or perhaps 30 consecutively spaced 1/10th gauge needles in alternating front and rear segments. In these highly varied patterning setups, the double looper configuration of
A configuration of particular interest employs a front needle bar of relatively narrower gauge consecutive needle placement in a central segment, in combination with a rear needle bar of relatively broader gauge with needle segments disposed at the ends for the purpose of tufting carpet with different edge characteristics. For instance, in the manufacture of rugs, it has been known to utilize auxiliary yarn feeds to tuft side borders as described in U.S. Pat. No. 5,544,605. By utilizing for instance a front needle bar with 1/10th gauge needle spacing in a central segment and rear needle bar with needles located in approximately six to twelve inch segments at the extreme right and extreme left of the width of the tufting machine and ⅕th gauge needle spacing, the rear needle bar can be threaded with different yarns or yarn sequences and shifted differently than the front needle bar with its central segment of tighter spaced needles to optimize tufting of carpet with distinct border sections.
Another configuration of interest is shown in
This provides the option of seizing or not seizing loops of yarn from the needles, or alternatively seizing loops of yarn from the front needle bar that are subsequently withdrawn by back-robbing. The use of extensible loopers with segmented needle bars provides even greater patterning versatility and precision.
It can be seen that the use of blocks of needles, on either a single needle bar (as by re-arranging the needles from a traditional staggered configuration), or on two independently shiftable needle bars as illustrated, provides a tufting machine with diverse patterning and manufacturing capabilities. A variable gauge tufting machine could be configured to make 1/10th gauge fabric (or other gauges) with conventional front and rear ⅕th gauge needle bars, or with segmented 1/10th gauge needle bars. The use of segmented needle bars provides for different yarn placement strategies and may reduce backstitch yarn by reducing the gauge distance of lateral shifts of the needle bar, and may minimize zones where yarns from the rear needles 14b rear needle bar 112b would overtuft yarns previously tufted by front needles 14a.
Numerous alterations of the structure herein described will suggest themselves to those skilled in the art. It will be understood that the details and arrangements of the parts that have been described and illustrated in order to explain the nature of the invention are not to be construed as any limitation of the invention. All such alterations which do not depart from the spirit of the invention are intended to be included within the scope of the appended claims.
The present application claims the benefit of U.S. Provisional Ser. No. 62/975,256 filed Feb. 12, 2020.
Number | Date | Country | |
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62975256 | Feb 2020 | US |