Dual sliding needle bar tufting apparatus

A tufting machine has two slidable needle bars in back-to-back relationship, each needle bar being reciprocated toward and away from a backing material in unison. Each needle bar carries a plurality of transversely spaced apart needles mounted in needle modules, the needles in one bar being staggered relative to those in the other bar. The needles in both needle bars may cooperate with identical hooks positioned on the opposite side of the backing material. Each needle bar is slidable transversely independently of the other needle bar. The gauge between needles in each needle bar is twice the gauge between the hooks and the hooks have a common throat length so that each hook may cooperate with a needle in either needle bar. Thus each needle bar may be shifted transversely by a distance equal to the pitch between needles of the composite needle bar assembly rather than the larger pitch between needles in the same needle bar as in the prior art. This permits the gauge at which a particular yarn may be shifted to be substantially equal to half the gauge of that capable in the prior art so that substantially improved pattern definition may result.

BACKGROUND OF THE INVENTION 
This invention relates to tufting machines and more particularly to a 
tufting machine having at least two sliding needle bars with the needles 
in each bar staggered relative to those in the others, the needle bars 
being capable of producing stitches at a gauge substantially less than the 
prior art. 
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 loops of yarn into a backing material 
fed longitudinally beneath the needles. The loops are seized by loopers or 
hooks oscillating below the fabric in timed relationship with the needles 
as the loopers or hooks cross the needles just above the needle eye. In 
loop pile machines the loopers point in the direction in which the backing 
material is being fed, hold the seized loops while the needles are being 
retracted from the backing, and thereafter move away from the point of 
seizure to release the loops. In cut pile machines the hooks point in the 
direction opposite to the direction in which the backing material is being 
fed so the loops are fed onto the hooks and each hook cooperates with a 
respective oscillating knife. Since the loops are fed toward the closed 
end of the hook they cannot be released except by being cut by the 
respective knife. As the hook rocks away from the point of loop seizure 
the knife rocks upwardly and cuts the loop. During each penetration of the 
backing material a row of pile is produced transversely across the backing 
material. Successive penetrations result in a longitudinal row of pile 
produced by each needle. 
This basic method of tufting limits the aesthetic appearance of tufted 
fabrics so produced. Thus, the prior art has developed a number of 
procedures for creating various pattern effects. 
One such procedure for patterning is to initiate relative lateral movement 
between the backing material and the needles to laterally displace 
longitudinal rows of stitching. One method is to jog or shift the needle 
bar endwise or laterally across the tufting machine relative to the base 
material in a step-wise manner in accordance with a pattern, that is the 
needle bar is slidable in the longitudinal direction thereof. The patented 
art is abound with disclosures relating thereto, and Ingram U.S. Pat. No. 
4,392,440 is exemplary thereof. 
The use of a single straight needle bar greatly constrains the versatility 
of a tufting machine thereby limiting the patterning capabilities. This 
versatility can be increased by using a laterally shiftable needle bar 
having staggered needles, i.e., a needle bar wherein adjacent needles are 
offset in the backing material feed direction. Staggered needle cut pile 
machines without a shiftable needle bar are illustrated in Crumbliss et al 
U.S. Pat. No. 3,913,505 and Card U.S. Pat. No. 4,003,321. When a shiftable 
or sliding needle bar is utilized with staggered needles a temporary 
crossing-over of adjacent yarns occurs thereby resulting in a greater 
variety of patterning effects. 
It is also known to use two separately slidable back-to-back needle bars 
each having straight or side-by-side inline needles, i.e., one row of 
needles in each bar, so as to separate the two rows of needles of a 
staggered needle bar configuration onto separate needle bars which can be 
moved independently of one another to bring each needle into cooperative 
registration with a hook or looper at a given pitch position corresponding 
to the respective needle bar. This creates a much greater facility to 
cross one row of yarns and needles over the other row of yarns and needles 
to provide greater patterning effects. 
As explained in the aforesaid Crumbliss et al U.S. Pat. No. 3,913,505 and 
the aforesaid Card U.S. Pat. No. 4,003,321, in conventional constructions, 
as used in the context of cut pile, the hooks cooperable with the needles 
in one row are of a different length than the hooks cooperating with the 
needles of the other row. That is, the throat length or distance from the 
bill to the neck of the hooks cooperating with needles of one row are of a 
different length than those of the hooks cooperating with the needles of 
the other row. Thus, in the prior art, as exemplified by Card U.S. Pat. 
No. 4,366,761, when there are two independent slidable needle bars or rows 
of needles, the hooks cooperating with a given needle bar can only 
cooperate with the needles in that bar. Thus, it is only possible to move 
a particular needle laterally by an amount consistent with a multiple of 
the pitch at which the needles are set on the relevant needle bar. That is 
to say each needle bar may only be shifted by an amount equal to a whole 
number multiple of the gauge or spacing of the needles in that needle bar, 
and which is twice the gauge of the composite needle bar assembly in dual 
shifting bars staggered needle tufting machines. This limitation manifests 
itself in a patterned tufted product as a lack of sharpness or definition 
in the pattern. 
SUMMARY OF THE INVENTION 
Consequently, it is the primary object of the present invention to provide 
a tufting machine having dual sliding needle bars each of which may be 
shifted laterally in a manner providing improved pattern definition. 
It is another object of the present invention to provide a tufting machine 
having means permitting lateral shifting of each needle bar of a multiple 
shifting needle bar assembly by an amount equal to the pitch or gauge of 
the needle assembly as a whole, as distinct from that existing in relation 
to one of the needle bars, whereby reduced gauge results thereby to 
improve the sharpness or definition of the pattern in a product produced 
thereby. 
It is a further object of the present invention to provide a tufting 
machine having at least two needle bars in close back-to-back 
relationship, each needle bar supporting a respective set of needles in 
uniformly spaced side-by-side relationship, the needle bars being movable 
laterally of the tufting machine for patterning purposes, and the loop 
seizing members having substantially common throat lengths for seizing 
loops from needles in either one or another of the needle bars. 
Accordingly, the present invention provides a tufting machine having a 
plurality of slidable needle bars in back-to-back relationship with 
minimal clearance therebetween so that each needle bar may be shifted 
laterally relative to the movement of backing material through the 
machine, each needle bar carrying a multiplicity of spaced apart 
side-by-side needles and having loop seizing members, either hooks or 
loopers, each having substantially the same throat length so as to seize a 
loop of yarn from needles of any of the needle bars whereby the needle 
bars may be shifted laterally by a distance equal to the lateral pitch 
between needles of the composite needle bar assembly rather than the 
larger pitch between needles in the same needle bar, the latter being a 
limitation of the prior art. 
In the preferred form of the invention there are two needle bars and each 
may be shifted by an amount substantially half the pitch between the 
needles in each bar. The back-to-back spacing between needles in the 
respective needle bar is minimized by the utilization of needles mounted 
in modules fastened to adjacent surfaces of the respective needle bars 
such that the back-to-back spacing between needles in the needle bars is 
approximately half of that in the prior art.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawings, and more particularly to FIGS. 1 and 2, 
conventionally in a tufting machine having a double sliding needle bar 
arrangement, the loop takers 10, which in a cut pile machine are hooks, 
are provided as two plural sets 12, 13, each cooperating with respective 
plural sets or rows of needles 14, 15 of a respective needle bar 16, 17. 
The hooks in each set are the same but the two sets are different in that 
the length of the respective throats 18, 19 differ, the difference in 
length being such that the hooks 12 having the longer throats 18 are 
cooperable uniquely with the front row of needles 14 while the other hooks 
13 have the shorter throats 19 and are cooperable only with the back row 
of needles 15, front and back rows being relative to the direction the 
backing material moves in a cut pile tufting machine, i.e., toward the 
neck at the closed end of the hooks. 
As can be appreciated from FIG. 2, while the nominal pitch A of the needles 
in the two needle bars or rows when considered collectively is half of the 
pitch B of the needles on a given needle bar, needle shift must 
necessarily be a multiple of the pitch B of the needles on the needle bar 
being moved so as to cooperate with the relevant hook 12 or 13. Thus, any 
particular yarn carried by the respective needles only can be moved 
laterally by a distance which is a multiple of twice the nominal pitch of 
the needles as a whole. 
The magnitude of such a shift militates against the provision of a sharp 
edge to a pattern, and this inevitably gives rise to a haziness or lack of 
definition of the pattern. In contradistinction to the prior art, the 
present invention provides a sharpness of pattern not attainable by prior 
art structures and gives rise to the creation of a more aesthetically 
pleasing patterned tufted product. 
Referring to FIG. 3, a tufting machine 20 constructed in accordance with 
the principles of the present invention is constructed so that all of the 
hooks 22 have throats of the same length and may cooperate with either the 
needles 24 mounted in the rear needle bar 26 or the needles 28 mounted in 
the front needle bar 30, each needle bar being laterally shiftable as 
hereinafter described relative to the direction in which backing material 
44 is fed through the tufting machine. The tufting machine comprises a 
head within which is secured a plurality of collars 32, only one of which 
is illustrated for supporting respective sleeves 34. Journally disposed 
within each sleeve is a push rod 36. Attached to the lower end of the push 
rods is a support foot 38, the foot being a split member clamped about the 
respective push rod and secured thereto by screws or the like. 
Securely carried in each foot 38 lying in a plane substantially normal to 
the axis of each push rod is a pair of guide rods 40, 41, the rods being 
fixedly secured to each foot and therefore reciprocably movable together 
with the respective push rods 36. The rods 40, 41 are spaced apart and 
each is journally mounted in a respective linear bearing carried in a pair 
of laterally spaced apart slide blocks 42, 43, there preferably being one 
block adjacent each lateral side of the foot 38. One of the blocks, e.g. 
block 42 is secured to a first needle bar, e.g. front bar 30 and the other 
block 43 is secured to the other needle bar 26 by conventional means so 
that reciprocation of the push rods effects reciprocation of both needle 
bars and the needles carried therein. As the needle bar reciprocates the 
needles penetrate the backing material 44 fed across the needle plate 
fingers 46 on the bed plate 48 of the machine. Each needle bar carries a 
respective set 24, 28 of aligned needles which are staggered one row or 
needle bar relative to the other as illustrated in FIG. 8. Each needle 24, 
28 cooperates with a respective loop taker, which in the embodiment 
illustrated comprises hooks 22 which cooperate with the needles for 
seizing loops of yarn as hereinafter further described. Lateral shifting 
of each needle bar results in the blocks 42, 43 moving along and relative 
to the guide rods, 40, 41, the shifting being effected by means 
hereinafter described. 
The upper end of each push rod 36 is connected through a wrist pin 50 or 
the like to a link 52 which is in turn connected by another wrist pin 54 
to a rocker arm 56 clamped to an oscillating mainshaft 58 so that rocking 
motion of the shaft 58 results in reciprocation of the needle bars 26, 30 
and thus the needles 24, 28. Rocking motion is supplied to the mainshaft 
58 through means including a camshaft 60 mounted in the head below and 
substantially parallel to the mainshaft and driven at one end of the 
machine by conventional means. A circular eccentric cam 62 is secured 
preferably adjacent each end of the camshaft and rotates therewith. A 
connecting rod 64 having a lower split end section is journalled on a 
sleeve 66 on the eccentric cam 62. The upper end of the connecting rod 64 
is connected in a slotted arcuate lever arm 68 of a drive lever secured at 
one end to the mainshaft. The slot 70 within the arm has an arcuate path 
having a center of curvature coinciding with the geometric center of the 
eccentrically mounted cam when the cam is at bottom dead center. Thus, the 
stroke of the push rods 36 may be adjusted and this may be accomplished 
without changing the bottom position of the needle stroke. Accomplishing 
this merely involves repositioning a bolt 72 connecting the connecting rod 
64 to the drive lever 68 within the slot which changes the amplitude of 
oscillation of the lever and effects a change in amplitude of rocking of 
the mainshaft 58 as is well known in the art. 
A similar drive arrangement to that for driving the push rods 36 driven 
from the camshaft 60 acts to drive a hook jack shaft 74 and a knife shaft 
76. A jack shaft rocker arm 78 is clamped to the jack shaft 74 and is 
pivotably connected at one end to a link 80 having its other end connected 
to the upper portion of a hook rocker arm 82 clamped at its lower end to 
an idler shaft 84 journalled in the bed of the tufting machine. The upper 
end of the hook rocker arm 82 carries a bar 86 which in turn carries the 
hook mounting bar 88-within which the hooks 22 are mounted in side-by-side 
relationship. A knife shaft rocker arm 90 is clamped to the knife shaft 76 
and secures a knife bar 92 which carries the knife mounting blocks 94 in 
which the knives 96 are mounted. Conventionally the throw or oscillating 
movement of the hooks and the knives are controlled by adjustable means 
such as the slotted arm construction described in respect to the push rod 
reciprocation adjustments. 
Referring to FIG. 5, to shift each needle bar 26, 30 laterally a pattern 
cam 98 may be rotatably mounted in a shifter 100 drive assembly supported 
adjacent a respective end of the tufting machine, the assembly carrying 
followers carried on brackets 104, 105. There is, of course, one such 
assembly to drive each needle bar independently of the other needle bar. 
Each assembly may be similar to that illustrated in U.S. Pat. No. 
4,465,001. The brackets 104, 105 are drivingly connected to slide rods 
106, 107 fastened to another bracket 108 connected to a driving rod 110. 
The driving rod 110 is secured to a block 112 which is straddled by a pair 
of rollers 114, 115 carried by a bracket 116 which may be secured to the 
respective needle bar such as the bar 30 or other means secured to the 
needle bar so that the needle bar may reciprocate relative to the block 
112 yet be moved laterally with the block as determined by the cam 98 and, 
of course, the needle bar when shifted laterally slides relative to the 
guide rods 40, 41 by means of the slide blocks 42, 43. 
In accordance with the present invention the needles carried by each needle 
bar 26, 30 are embedded within a plurality of needle modules or modular 
blocks 118, 119, somewhat similar to those illustrated in U.S. Pat. No. 
4,138,956, there being a substantial number such as, for example, 16 such 
needles embedded within each modular block 118, 119. As illustrated in the 
drawings the blocks 118, 119 are attached to facing surfaces of the 
respective needle bars 26, 30 by means of screws and are mounted 
back-to-back relative to one another so that the needles 24, 28 in the 
needle bars may be closely spaced to one another yet provide a clearance 
between the modular blocks 118, 119 to permit the needle bars to shift 
laterally relative to each other. To this end each needle module is 
identical but the needles are mounted such that the yarn grooves 120, 121 
face the same end of the tufting machine as do the clearance above the eye 
(not illustrated). Each module has an abutment flange 122, 123 which faces 
remote from the other so the needles are embedded in the modules in 
opposite manner at a disposition remote from the respective flange as 
illustrated in FIG. 6. In the prior art, the spacing between the needles 
14, 15 in FIGS. 1 and 2 is 1/4 inch. However, with the construction 
according to the present invention, the needles in one bar may be spaced 
only 1/8 inch from the needles in the other bar. Therefore, the hooks may 
all have the same length throat 124 extending from aligned necks 125 so 
that the throat length of the hooks may be equivalent to that of the 
smaller throat 19 of prior art hooks or a throat length somewhere between 
the short 19 and long throats 18 of the prior art hooks. Thus, the 
oscillation or throw of the hook arm 82 may increase slightly by the 
conventional adjusting means described so that a hook may seize a loop 
from needles in either needle bar. 
Thus, referring to FIGS. 7 and 8, with the needle bars arranged with the 
modules 118, 119 in closely spaced disposition in the direction of backing 
material feed, and the hooks having a common length sufficient to pick up 
loops from needles 28 mounted in the front needle bar 30 or needles 24 in 
the rear needle bar 26, the lateral shift of a yarn carrying needle may be 
a multiple of the pitch C of the needles as considered collectively in the 
double sliding needle bar arrangement, and may thus be equal to that 
pitch. Each shift made by each needle bar is not constrained by the unique 
throat length of the hooks since each hook has an identical throat length 
so each needle bar may be shifted a pitch equal to that of the hooks, 
which also is C. Consequently, the gauge at which a particular yarn may be 
shifted is substantially equal to half the gauge of that capable in the 
prior art so that clear pattern definition is obtainable. 
Numerous alterations of the structure herein disclosed will suggest 
themselves to those skilled in the art. However, it is to be understood 
that the present disclosure relates to the preferred embodiment of the 
invention which is for purposes of illustration only and not to be 
construed as a limitation of the invention. All such modifications which 
do not depart from the spirit of the invention are intended to be included 
within the scope of the appended claims.