OPTIMIZED BACKING SHIFTER FOR VARIABLE OR MULTI-GAUGE TUFTING

Abstract

Backing fabric shifting relative to needles and gauge parts for seizing yarns is utilized in a tufting machine having needle plate fingers or backing support that reciprocates in synchronization with the cycles of the needles to support the backing during penetration of the backing fabric while allowing backing shifts between stitches.

Claims

1. A method of operating a tufting machine of the type having a control system and a needle bar movable toward and away from a backing fabric by operation of a needle drive, said needle bar carrying a series of gauge-spaced and yarn-carrying needles transversely across a width of the tufting machine; a backing feed feeding the backing fabric through a tufting zone of the tufting machine; a yarn feed mechanism for feeding repeats of different yarns to the series of needles; a precision backing shifter for shifting the backing transversely relative to the tufting zone; a needle plate with needle plate fingers beneath the backing fabric equipped for reciprocal front-to-back movement; a series of gauge spaced parts mounted below the tufting zone in a position to engage the series of needles when penetrating the backing fabric by downward movement of the needle bar to form tufts of yarns in the backing material; comprising feeding the backing fabric from front to rear through the tufting machine while operating the needle drive to cause the series of yarn-carrying needles to penetrate the backing fabric when the needle plate is moved frontward, and shifting the backing fabric relative to the needles and gauge parts when the needle plate is moved rearward, the shifting of the backing fabric relative to the needles being by increments less than the gauge spacing of the needles, to thereby create a tufted fabric of a gauge distinct from the gauge spacing of the series of gauge spaced needles.

2. The method of claim 1 wherein the needle plate comprises a reciprocating plate having a plurality of needle plate combs with integrally formed needle plate fingers attached.

3. The method of claim 1 wherein the needle plate is moved reciprocatably from front-to-back by the operation of a rocker shaft.

4. The method of claim 1 wherein the needle plate is guided for reciprocable front-to-back movement by linear bearings on linear ball rail guides.

5. The method of claim 3 wherein a control system controls and synchronizes a drive motor for the rocker shaft, the needle drive, the backing feed, the precision backing system.

6. A method of operating a tufting machine of the type having a control system and a needle bar movable toward and away from a backing fabric by operation of a needle drive, said needle bar carrying a series of gauge-spaced and yarn-carrying needles transversely across a width of the tufting machine; a backing feed feeding the backing fabric through a tufting zone of the tufting machine; a yarn feed mechanism for feeding yarns of a single color to the series of needles; a precision backing shifter for shifting the backing transversely relative to the tufting zone; a needle plate beneath the backing fabric equipped for reciprocal front-to-back movement; a series of gauge spaced parts mounted below the tufting zone in a position to engage the series of needles when penetrating the backing fabric by downward movement of the needle bar to form tufts of yarns in the backing material; comprising feeding the backing fabric from front to rear through the tufting machine while operating the needle drive to cause the series of yarn-carrying needles to penetrate the backing fabric when the needle plate is moved frontward, and shifting the backing fabric relative to the needles and gauge parts when the needle plate is moved rearward, the shifting of the backing fabric relative to the needles for some penetrations of the needles by increments less than the gauge spacing of the needles creating a tufted fabric without streaking.

7. The method of claim 6 wherein the needle plate comprises a reciprocating plate having a plurality of needle plate combs with integrally formed needle plate fingers attached.

8. The method of claim 6 wherein the needle plate is moved reciprocatably from front-to-back by the operation of a rocker shaft.

9. The method of claim 6 wherein the needle plate is guided for reciprocable front-to-back movement by linear bearings on linear ball rail guides.

10. The method of claim 8 wherein a control system controls and synchronizes a drive motor for the rocker shaft, the needle drive, the backing feed, the precision backing system.

11. A tufting machine for forming tufted fabrics, comprising: a needle bar movable toward and away from a backing fabric by operation of a needle drive, said needle bar carrying a series of gauge-spaced yarn-carrying needles transversely across a width of the tufting machine; a backing feed feeding the backing fabric through a tufting zone of the tufting machine; a yarn feed mechanism for feeding yarns to the series of needles; a backing shifter for shifting the backing transversely relative to the tufting zone; a needle plate beneath the backing fabric equipped for reciprocal front-to-back movement; a series of gauge spaced parts mounted below the tufting zone in a position to engage the series of needles when penetrating the backing fabric by downward movement of the needle bar to form tufts of yarns in the backing material; a control system for controlling and synchronizing the backing shifter, the needle drive, the backing feed, and the front-to-back movement of the needle plate.

12. The tufting machine of claim 11, wherein the needle plate comprises a reciprocating plate having a plurality of needle plate combs with integrally formed needle plate fingers attached.

13. The tufting machine of claim 12, wherein the needle plate fingers are rearwardly extending and the series of gauge-spaced needles pass between the needle plate fingers when reciprocated into the backing fabric.

14. The tufting machine of claim 11, wherein the needle plate is moved reciprocatably from front-to-back by the operation of a rocker shaft.

15. The tufting machine of claim 11, wherein the gauge parts are loopers.

18. The tufting machine of claim 11, wherein the series of gauge-spaced needles is spaced transversely in a row having a gauge of 5/16ths, ⅕.sup.th, ⅙.sup.th, ⅛.sup.th, 1/10, 6/16ths, 10/32nds or 1/12.sup.th inches.

19. The tufting machine of claim 11, wherein the backing shifter is operable to shift the backing feed rolls transversely at least on inch from center position.

20. The tufting machine of claim 11, comprising a second needle bar movable toward and away from a backing fabric by operation of the needle drive, said needle bar transversely carrying a second series of gauge-spaced yarn-carrying needles.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] 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:

[0016] FIG. 1 is a partial sectional end view of a prior art tufting machine with a single row of needles that can be operated to place yarns in the manufacture of fabrics with cut and loop face yarns;

[0017] FIG. 2 is a top sectional view of a single row of needles and loopers that can be used in the manufacture of loop pile tufted fabrics;

[0018] FIGS. 3A-3F are sequential front plan view of a tufting cycle of shifting backing feed and reciprocating needle plate through a tufting cycle;

[0019] FIGS. 4A-4F are sequential side plan views of a tufting cycle corresponding to FIGS. 3A-3F.

[0020] FIGS. 5A-5F are sequential front perspective views of a tufting cycle corresponding to FIGS. 3A-3F.

[0021] FIG. 6A is a side plan view of a prior art presser foot assembly for backing shifter used on a hollow needle type tufting machine.

[0022] FIG. 6B is a top plan view of the presser foot assembly illustrated in FIG. 6A.

[0023] FIG. 7 is a side sectional view of a prior art shiftable cloth feed assembly used on a hollow needle type tufting machine.

[0024] FIG. 8A is a side plan view of a prior art tension roll assembly used on a hollow needle type tufting machine.

[0025] FIG. 8B is a front plan view of the tension roll assembly of FIG. 8A.

[0026] FIG. 9 is a perspective view of the backing shifting apparatus in isolation.

[0027] FIG. 10A is an exploded view of a section of an exemplary needle plate assembly.

[0028] FIG. 10B is a perspective view of the reciprocating needle plate of FIG. 10A as put together for operation.

[0029] FIG. 11 is a partial sectional perspective view of an end of a tufting machine showing a servo motor drive for a reciprocating needle plate apparatus and equipped with a backing shifter.

[0030] FIG. 12A is a top plan illustration of the needles and needle plate fingers of a reciprocating needle plate for a single row of needles.

[0031] FIG. 12B is a top plan illustration of the location of the needles and needle plate fingers of a reciprocating needle plate for two rows of needles.

[0032] FIG. 13A is a partially exploded perspective view of an alternative needle plate drive assembly.

[0033] FIG. 13B is an exploded view of a needle plate assembly with laser cut needle finger “combs.”

[0034] FIG. 13C is a perspective view of a laser cut needle finger comb.

[0035] FIG. 13D is a side plan view of the rocker arm assembly of the alternative needle drive assembly of FIG. 13A.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

[0036] Referring now to the drawings in more detail, FIG. 1 discloses a multiple needle tufting machine 10 including an elongated transverse needle bar carrier 11 supporting a needle bar 12. The needle bar 12 supports a row of transversely spaced needles 14. The spacing of the needles is referred to as the “gauge” of the needle bar. The needle bar carrier 11 is connected to a plurality of push rods 16 adapted to be vertically reciprocated by conventional needle drive mechanism, not shown, within the upper housing 26.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] It can be seen in FIG. 1 that the tufted greige 35 with backstitch side 44 and face side 45 is lifted away from the tufting zone after passing presser foot 101. When employing a backing shifter, it is necessary to move the face side 45 away from the hook apparatus of a cut pile or cut loop configuration as the lateral shifting of the backing could cause interference between the tufted yarns on the face 45 and the hooks 41. For the purposes of using the backing shifting apparatus of the present invention, it is preferable that the yarn seizing gauge parts be loopers that are disengaged from the loops of yarn after each stitch rather than hooks that often need to carry a yarn for one or more additional stitches to effect a cut pile.

[0043] FIG. 2 is a top view of a needle bar with a single row of needles 14 associated with loopers 31 and where a backing fabric, not shown, would pass over needle plate 25 and needle plate fingers 22 for tufting. The loopers 31 reciprocate in the forward direction when not seizing loops of yarn, in a fashion opposite to the movement of gated hooks 41 or cut pile hooks, and as a result tend to be away from the face side 45 of the tufted greige 35. This makes loopers 31 less likely to interfere with yarns tufted on the face of the greige when the backing is laterally shifted. Therefore most implementations of the present invention more useful with loop pile configurations.

[0044] FIGS. 3A-F and corresponding views in FIGS. 4A-F and 5A-F illustrate the tufting zone movement of the needle plate fingers 22 in the new shiftable backing fabric design. It can be observed in FIGS. 3A, 4A, 5A that the needle plate finger 22 extends essentially to the presser foot and through much of the diameter of the needle 14 passing behind the needle plate finger. As the needle 14 moves upward retracting from the backing fabric, the needle plate finger is similarly retracted toward the front of the tufting machine as shown in FIGS. 3B, 4B, 5B. In FIGS. 3C, 4C, 5C, the needle is free of the backing fabric and space exists between the needle plate fingers 22 and presser foot. As the needles 14 again move downward in FIGS. 3D, 4D, 5D, the needle plate fingers 22 move forward to support the backing fabric and remain in that position through the downward stroke as shown in FIGS. 3E, 4E, 5E but again begin to retract as needles 14 are removed from the backing fabric in FIGS. 3F, 4F, 5F.

[0045] The reciprocating needle plate fingers of FIGS. 3-5 are suitable to be mounted in a slightly modified prior art backing shifting assembly such as that shown in FIGS. 6-9, with presser foot supports 111, 112 presser foot support angles 113, 114, presser foot plate 115, presser manifold 116. as shown in FIGS. 6A and B. FIG. 7 shows the prior art cloth feed assembly with bearing support bracket 211, bedplate rail 212, bearing housings 213, 214, three inch roll supports 215, 216, one inch roll supports 217, 218, support plate 219, nut bar 210, three inch tension rolls 204, 205, one inch pin rolls 202, 203, drive rods 229, 230, drive blocks 231, 232, and corner angle 39. Bearings 201 allow the roll supports 215-218 to move laterally with respect to the bearing support brackets 211 that are secured to the tufting machine. The needle plate 219 is replaced by a reciprocating needle plate as shown in FIGS. 10 and 11.

[0046] FIGS. 8A and 8B show the tension roll assembly of FIG. 7 mounted on frame 100, and the three principal lateral frame beams 100A, 100B, 100C. FIG. 9 shows the shifting mechanism of that moves the entire cloth feed/backing feed assembly, including tension rolls, laterally with respect to the tufting machine. Liner drive motors 207 connect to drive blocks 231, 232 and thence to drive rods 229, 230 to communicate lateral movement to the tension roll assembly.

[0047] Turning then to FIG. 10A, an exploded view of a reciprocating needle plate assembly 140 is shown. A base plate 150 secured to the tufting machine carries pillow blocks 151 with bearings to permit the rotation of shaft 142. Also, linear rail ball guides 155 are mounted to the base and the reciprocating needle plate 143 is mounted on those guides to control the longitudinal movement of the plate. The shaft 142 carries a cam 146 between collars 153 and thrust bearings 152 and pillow blocks 151. The cam 146 is set in a sleeve bearing 147 in one end of a connecting rod 145. The other end of the connecting rod 145 has a sleeve bearing 148 and is joined by a dowel 149 to wrist block 144 that is in turn fastened to the needle plate 143. Alternatives to provide reciprocating support to the backing fabric in the tufting zone at the time of needle penetration but clearance from the greige for laterally shifting the fabric relative to the needles and loop seizing gauge parts may be utilized with similar effect.

[0048] 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.

[0049] In FIG. 10B, it can be seen that the rotation of shaft 142 operated the cam to effect movement of the connecting rod 145 and the linear rail ball guides direct the needle plate 143 with rearwardly projecting needle plate fingers 22 to reciprocate in a forward and rearward direction. This movement corresponds to the movement shown in FIGS. 3-5. As shown in FIG. 11, shaft 142 is rotated by servo drive 141 and this means of control allows for alterations to the timing, or reciprocation window, relative to the position of the needles in an independent and rapid fashion. Other techniques for driving reciprocating backing support, such as needle plate or needle plate fingers, are possible such as by linkage with other driven systems such as the main drive motors or looper drive, the use of pneumatics, hydraulics, or linear drive motors.

[0050] FIGS. 12A and 12B show the relative locations of needle plate fingers 22 and needles 14 in exemplary arrangements of one row of needles (FIG. 12A) and two rows of needles (FIG. 12B). When using a single row of needles 14 the needles are directly between needle plate fingers 22a, 22b at the time of penetrating the backing fabric. However, when two rows of needles are used, the front row of needles 14a are directly between needle plate fingers 22a at the time of penetrating the backing fabric. At this point, the rear row of needles 14b are located just beyond the ends of needle plate fingers 22a. Thus, the backing fabric near front needles 14a is supported by needle plate fingers 22a on either side, but the fabric near rear needles 14b is supported only by the end of the adjacent needle plate finger 22a. To improve the fabric support, in either case, it is sometimes helpful to place a riser beneath the face of the tufted greige to lift the tufted fabric upward as soon after the presser bar as practicable. Needle plate fingers 22 have conventionally been wires or similarly formed metal pieces of uniform cross section fitted into grooves of the needle plate as in U.S. Pat. Nos. 4,548,140 and 7,107,918, or even cast into modular blocks.

[0051] FIG. 13A shows a alternative needle plate drive that operates with a rocking action generated by connecting link and eccentric. This mechanism allows the needle plates to be pushed forward for needle plate fingers to provide support to the backing fabric in the tufting zone and rearward to provide clearance from the greige for shifting the greige fabric relative to the gauge parts by a rocker shaft rather than being driven directly by eccentrics on a rotating drive shaft. The use of a rocker shaft reduces the number of loose yarn fibers that entrain themselves about the shaft since the oscillating motion of the shaft tends to dislodge fibers that might fall upon it. This is in contrast to a shaft continually rotating in a single direction which may more easily entrain fibers around its circumference and foul the operation of the needle plate movement apparatus. In addition, the needle plate fingers 222, rather than being individually mounted in blocks or formed from steel fingers cast into modular blocks, are instead cut from a sheet of durable metal, preferably in a four to six inch length as depicted in FIG. 13C. By laser cutting the needle plate fingers 222 from steel or titanium blanks, for instance, the fingers 222 may be shaped slightly to have a wider base 201 tapering to the ends 202 and providing a stronger and more versatile structure than if the fingers were uniform over their entire exposed length.

[0052] FIG. 13B shows the assembly of these needle finger comb plates 225 being attached to the reciprocating plate 230 mounted on bearing pillars 239 with linear rail ball guides 247 for reciprocation by the rocker shaft 256. The assembly is shown in FIG. 13A with servo motor 141 operating on cam shaft 253 which passes through a spindle bracket 251 and servo mount bracket 252 to drive an eccentric in the top end of connecting link 100 on the cam shaft, secured by retaining ring 267 and rotatably connected at the bottom end with bearing 264 to drive lever assembly 255, in turn imparting rotational movements to the rocker stub shaft 257.

[0053] When driven by servo motor 141 action of the cam on cam shaft 253 causes connecting link 260 to oscillate and thereby imparts back and forth rotational motion through the drive lever assembly 255 to the rocker stub shaft 257. Rocker stub shaft 257 is in turn connected by coupling 266 to rocker shaft 256. The rocking of rocker shaft 256 imparts linear motion through connecting link assemblies 254 that have one end attached to rocker shaft 256 with rocker arm assemblies 258 and the opposite end attached to drive pins 220 mounted in wrist blocks 250 with thrust bearings 240 and set screws 290. The driven wrist blocks 250 are secured by screws 228 intermediate the rearward extending support plate castellations 231 that are attached to linear bearing blocks 239 that guide the motion of the support plate 230 and needle plate combs 225 in a reciprocating linear fashion below the backing fabric.

[0054] In addition to utilizing a rocking motion which lessens the likelihood for winding fibers about a rotating shaft, the rocker shaft structure provides greater clearance than the rotational shaft assembly. Furthermore, the rocker arm assembly 258 connection to the rocker shaft 256 allows for bed plate height changes of at least 0.0125 inches without reconfiguring or recalibrating the needle plate assembly.

[0055] 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 ⅛.sup.th gauge tufting machine and provides numerous patterning advantages. Furthermore, an ⅛.sup.th gauge tufting machine can very nearly imitate a 1/10.sup.th gauge tufting machine, although not all stitches will appear in perfectly aligned rows. By way of example, a ⅛.sup.th 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 1/10.sup.th 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 ⅛.sup.th 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.

[0056] 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 3/16.sup.th 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 backstitch that is effectively lost to effective use.

[0057] 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.