CLAMP INSERT FOR TUFTING ELEMENTS IN NARROW "' GAUGE TUFTING MACHINE Technical Field This invention relates to a multiple-needle tuft- ing machine, and more particularly to a clamp insert for tufting elements in a narrow gaucre tufting machine.
Background Art The conventional hook bars for multiple-needle tufting machines are long bars extending transversely of the machine below the needles and the base fabric. A conventional cut-pile hook bar has deeply elongated slots formed through its bottom face and uniformly spaced for receiving the hooks which cooperate with the needles to form loops in the yarns carried by the needle. For a narrow gauge, multiple-needle tufting machine, the looper slots in the hook bar must be form¬ ed close together. The proximity of the spacing of the looper slots is limited by the thinness of the walls between the slots. Conventional looϋers of hooks are held in their respective slots by individual set screws which are threaded into each slot and engage the opposed walls or lands of the slots. Thus, the thinness of the walls is further limited by the diameters of the set screws. Moreover, the threaded movement of the set screws tends "to expand and warp the .slot walls or lands .
One solution to spacing the looper slots closer together in a narrow gauge tufting machine is dis¬ closed in the prior U.S. Patent No. 3,635,177, issued January 18, 1972 to Larry P. Gable et al for NARROW
GAUGE HOOK BAR FOR TUFTING MACHINE. The Gable patent discloses a hook bar having uniformly spaced, but staggered, looper slots formed alternately in the front and rear faces of the hook bar. Thus, the staggered front and rear slots receive two transverse rows of
staggered hooks or loopers for cooperation with corres¬ ponding staggered needles. However, the hook bar dis¬ closed in the Gable patent was primarily designed for a looper apparatus for forming narrow gauge loop pile. Another method of spacing the hook slots closer to¬ gether in a narrow gauge tufting machine is disclosed in U.S. Patent No. 4,067,270 of Hoyt E. Short for NARROW GAUGE CUT PILE TUFTING APPARATUS, in which the needles are staggered and the loopers are made quite thin and flexible for bending and veering around each of the corresponding staggered needles.
A further solution for spacing loopers and hook slots closer together in a narrow gauge machine is disclosed in U.S. Patent No. 4,158,399 of Hoyt E. Short, issued June 19, 1979, for NARROW GAUGE CUT PILE LOOPER APPARATUS. In this narrow gauge cut-pile tufting machine, the needles are staggered and the slots are formed in the front and rear faces of the hook bar. However, the slots are de¬ signed to extend along the top of the hook bar to receive and reinforce the elongated body portions of the specially constructed looper hooks.
Another type of hook bar or looper apparatus for mounting a plurality of looper hooks close together in order to provide a more narrow gauge for multiple-needle tufting machines, is disclosed in U.S. Patent No. 4,217, 837, of Max M. Beasley et al, issued August 19, 1980, for FINE GAUGE LOOPER APPARATUS FOR IN-LINE TUFTING MACHINE. In this looper apparatus, the hook slots are formed in an insert bar received in the front face ofthe hook bar, and the looper hooks are held in position by a plurality of clamp members threadedly secured to the hook block and against the front body portions of the looper hooks. The hook bars are made in the form of elongated modules which are mounted end-to-end and each of the clamp members is adapted to secure a limited number of hooks upon the hook bar module.
In recent times, a plurality of thin hooks have"' been mounted securely and precisely in a hook bar by casting the metal forming the hook bar around the pre¬ set hooks. However, although strength, rigidity, and precision are attained, nevertheless, an entire cast module of hooks must be discarded if only a single hook becomes defective.
Modular hook bars including gauge inserts for re¬ ceiving the loop hooks are disclosed in the co-pending application of Kenneth C. Curtis, et al, S.N. 447,974, filed January 26, 1983, for MODULAR HOOK BAR WITH GAUGE INSERT FOR TUFTING MACHINE, now US Patent No. 4,448,137 issued May 15, 1984. This application is assigned to TUFTCO CORPORATION, the same assignee of the instant application. Even though the above hook bar structure with the gauge inserts operates advantageously, never¬ theless, each looper hook is still retained in position in its gauge insert by a set screw. There must be one set screw for each loop hook. Thus, the fineness of the gauge is limited to a certain extent by the thick- ness or diameter of each set screw. Moreover, the fine¬ ness of the gauge is also limited by the number and thick¬ ness of. the individual slots, each of which receives a separate looper hook.
Conventional needle bars for multiple needle tufting machines are long continuous, solid bars extending trans¬ versely of the machine above the base fabric for the entire width of the fabric to be tufted. A conventional needle bar includes a plurality of needle holes extend¬ ing vertically through the needle bar and desirably para- llel to each other, uniformly spaced at the desired needle gauge. Each needle is inserted through the needle hole in the bottom of the needle bar so that each needle extends substantially the full height, if not the full height, of the needle bar. The needles are secured in position in their respective needle holes by transverse set screws.
The conventional needle bar has always been one" of the most difficult parts of a tufting achine to manufacture, since the numerous needle holes must be drilled very accurately in the long needle bar. It is extremely difficult to control the path of the drill bit through a needle bar which is usually 7/8" in depth or height. In the drilling operation, the drill bit often "leads off" in one direction or another at an angle to the vertical. Accordingly, such angular drill holes through the needle bar will not be parallel to each other. Therefore, the elongated needles extending through the angular needle holes would be "off gauge" where the needle holes are not drilled in truly vertical paths. The longer the needle, therefore, the greater the gauge error. The "lead off" of the drilling paths for each-needle hole may be caused by various factors. A drill bit which is not accurately ground, or a drill bit being forced too rapidly into the metal of the needle bar, or a drill bit striking the more dense or harder portion of the metal in the needle bar, can cause the drill bit to deflect from its truly vertical course.
Once the drilling of the conventional needle bar has commenced, it is not possible to determine the path of the drill bit- until it emerges from the opposite side of the needle bar. In a multiple needle tufting machine having several hundred needles, the gauge errors between the needles caused by the inaccurate drilling of the needle holes can create considerable problems.
Not only does the drilling of the needle holes in- volve maintaining accurate control of the drilling paths of the drill bits, but occasionally a drill bit will break off in the drilled needle hole, and the broken drill bit cannot be removed without damaging the needle bar. All of the above problems in the drilling of the needle holes can result in a needle bar which cannot be used and which must be discarded or scrapped.
Normally, it takes approximately 40 man-hours to* drill all of the required needle holes in a conven¬ tional needle bar of a multiple needle tufting machine.
Some of the above problems have been overcome by a segmental needle bar, such as that disclosed in the co-pending patent application of JERRY T. GREEN et al, S.N. 464,410, filed February 7, 1983, for SEGMENTAL NEEDLE BAR FOR MULTIPLE NEEDLE TUFTING MACHINE, new US Patent No. 4,483,261 issued November 20, 1984, assigned to the same assignee, TUFTCO CORPORATION. However, in the above-described segmental needle bar, there must be one set screw for each needle.
Disclosure of the Invention It is therefore an object of this invention to provide in a multiple-needle tufting machine an i - proved clamping mechanism for securing tufting elements, such as looper hooks and needles within their respective hook bar and needle bar, which will permit a narrow needle gauge, as fine as 1/16 of an inch (0.0625 inches) a. gauge , which it is believed has not been previously achieved.
The clamp mechanism contemplated by this invention is utilized in combination with a slotted gauge insert, which permits holding two or more tufting elements, in a single slot' ith a single set screw. Thus, only one set screw for each two hooks or two needles is required. Furthermore, a clamp mechanism made in accordance with this invention is capable of being utilized, with slight modification, either for holding looper hooks in a hook bar and/or needles in a needle bar. The structure and function of the clamp mechanism for both the looper hook and the needle is substantially the same.
More specifically, the hook bar or needle bar is made of elongated solid bar stock having an elongated recess opening through one face thereof. A gauge member having a plurality of longitudinally spaced slots is re¬ ceived within the elongated slot of the needle bar or hook bar. Each slot within the gauge member is large
enough to receive two tufting elements, that is two looper hook shanks or two needle shanks together with a T-shaped clamp member having a divider wall or stem inserted into the σauge slot between the tufting ele¬ ments. A set screw threaded through one surface or wall ofthe elongated bar, extends into the recess and bears against the head of the T-shaped clamp member to secure the pair of tufting elements within their corresponding slot.
By virtue of the above-described construction, the device is readily adaptable to receive and hold the tufting elements on a very fine or narrow gauge with 1/2 the number of receiving slots and 1/2 the number of set screws normally utilized for retaining hooks and needles in their respective hook bars and needle bars.
In the hook bar, the recess opens forward to re¬ ceive the slotted gauge member, looper hooks, and clamp members. The elongated recess in the needle bar opens' downward to receive the slotted -gauge member, needles, and clamp members.
Brief Description of the Drawings FIG. 1 is a fragmentary sectional elevation taken along the line '1-1 of FIG. 3, longitudinally through a portion of a narrow gauge, staggered-needle tufting mach- ine, incorporating a cut-pile looper apparatus made in accordance with this invention, and disclosing the needles and looper hooks in operative loop-forming po¬ sitions;
FIG. 2 is a fragmentary top plan view of the looper apparatus, taken along the line 2-2 of FIG. 1, with portions broken away;
FIG. 3 is a fragmentary front elevation of the looper apparatus, taken along the line 3-3 of FIG. 1, with portions broken away and with the knives removed;
FIG. 4 is a fragmentary, top front perspective -• exploded view of the looper apparatus , with the parts disassembled;
FIG. 5 is a fragmentary sectional elevation, sim- ilar to FIG. 1, but disclosing a modified form of the clamping mechanism utilized in combination with the needle bar;
FIG. 6 is a fragmentary front elevation of the needle bar disclosed in FIG. 5, with portions broken away;
FIG. 7 is a fragmentary bottom plan section taken along the line 7-7 of FIG. 5, with portions broken away;
FIG. 8 is an enlarged fragmentary bottom plan sec¬ tion, similar to FIG. 7; and FIG. 9 is a fragmentary top front perspective, ex¬ ploded view of the needle bar assembly, with the parts disassembled.
Best Mode for Carrying Out the Invention Referring now to the drawings in more detail, FIG. 1 discloses a transverse needle bar 10 in a conventional multiple-needle tufting machine supporting a first row of uniformly spaced front needles 11 and a second row of uniformly spaced rear needles 12 offset preferably mid-way between the front needles 11, to provide a uni- form, narrow -gauge, staggered needle tufting machine.
The needle bar 10 is vertically reciprocated by conven¬ tional means, not shown, to cause the front and rear needles 11 and 12 to move between an upper position (not shown) above the base fabric 13 to a lower position (FIG. 1) penetrating the base fabric 13, so that the needles will then carry yarns 14 and 15 through the base fabric 13 to form loops of tufting therein. The base fabric 13 is supported upon a needle plate 16 for move¬ ment, by means not shown, in the direction of the arrow in FIG. 1, that is longitudinally from front-to-rear through the machine.
The looper apparatus 18 which cooperates with t"he needles 11 and 12 includes a transverse hook bar 20 sup¬ ported upon a plurality of transversely spaced brackets 22 fixed to corresponding rocker arms 23 journaled on a rock shaft, not shown, and driven by conventional means, not shown, connected to the rocker arms 23 for limited reciprocable movement in synchronism with the recipro¬ cal)le movement of the needles 11 and 12. The hook bar 20 has an upper portion and a lower portion, and an upper front face 25, a lower angular outer surface 26 and a lower face surface 27. The hook bar 20 also in¬ cludes a top surface 28.
Formed in the solid metal hook bar 20 is an elonga¬ ted, transversely extending recess 30 which opens for- ward through the upper face 25, and is open in the trans¬ verse direction of the recess 30, but is otherwise en¬ closed to form the top inner surface 31, rear inner surface 32, and bottom inner surface 33.
Received within the recess 30 is an elongated, trans- versely extending, gauge member or gauge bar 35 compri¬ sing an elongated top wall 36 having a top bearing sur¬ face and from which depend a plurality of uniformly trans¬ versely spaced lands or partition walls 37, between which are formed insert slots 38. The insert slots 38 are uni- for ly transversely spaced at a gauge which is a multiple of the needle gauge, or twice the needle gauge as dis¬ closed in the drawings. The insert slots 38 are disposed in parallel vertical planes so that the insert slots 38 extend from front-to-rear completely through the gauge member 35 and open through the bottom portion of the gauge member 35.
The front-to-rear dimension of the gauge member 35 is disclosed in the drawings as being approximately equal to the front-to-rear dimension of the recess 30. The height of the gauge member 35 is slightly less than the height of the recess 30. The height of the gauge member
35, as well as the height of the recess 30, is sub-"" stantially less than the height of the hook bar 20, so that the major portion of the hook bar 20 is of solid material and lends substantial strength and sta- bility to the retention of looper hooks 40 and 40' within the hook bar 20.
Each looper hook 40 has a body portion including a substantially elongated, relatively straight, rear¬ ward projecting shank or shank portion 41 adapted to fit within the major portion of the corresponding insert slot 30. The neck or head 42 of the looper hook 40 forming a part of the body portion, defines a rear ver¬ tical surface or shoulder 43 which intersects the shank portion 41. Projecting forward from the neck or head 42 of the looper hook 40 is an elongated bill 44, hav¬ ing a barbed free end portion 45, defining a bottom cutting edge 46 intersecting the throat 47.
The width of each insert slot 38 is great enough to receive a pair of hook shank portions 41 and 41' in spaced apart relationship within the corresponding in¬ sert slot 38.
To retain the shank portions 41 and 41' within the corresponding insert slot 38, a clamp member 50, prefer¬ ably having a T-shaped cross-section, comprises an elongated divider member 51 and an enlarged head or bear¬ ing flange 52 projecting from opposite sides of one edge portion of the divider member 51, as best disclosed in FIGS. 3 and 4. The portions of the bearing flange 52 projecting beyond the side faces of the divider member 51 consititute seats 53 for supporting the shank portions 41 and 41' of the respective hooks 40 and 40'. The width or thickness of the divider member 51 approximately equals the space between the shank portion 41 and 41' when re¬ ceived within the slot 38. In other words, the sum of the thicknesses of the hook shank portions 41 and 41' and the thickness of the divider member 51 is substantially equal to the width of the corresponding insert slot 38. Furthermore, as best disclosed in FIG. 1, the sum
of the thickness of the top wall 36 of the gauge member 35, the height of the shank portion 41 and the height of the clamp head 52 are slightly less than the height of the elongated recess 30. Arranged in the same vertical longitudinal plane of each insert slot 38 is a threaded hole 54 extending at an upward and rearward angle through the outer surface 26 and the solid material of the hook bar 20, opening into the recess 30. A set screw 55 is threaded through the threaded opening 54 until its operative or upper end 56 engages the vertically aligned head 52 of the T-clamp member 50, when assembled with a pair of hooks 40 and 40' within a corresponding insert slot 38, as best disclosed in FIG. 3. Thus, when the screw 55 is tightened, as disclosed in FIG. 1, the engagement of the bearing end 56 of the set screw 55 against the flange or clamp head 52 forces the clamp head 52 against the lower surfaces of the shank portions 41 and 41' to force them upward into their corresponding insert slot 38. The upper edges of the shank portions 41 and 41' engage 'the lower sur¬ faces of the top wall 36 of the gauge member 35. Thus, the shank portions 41 are firmly secured within their corresponding slots 30 of the hook bar 20.
Formed on the upper front face 25 of the hook bar 20 above the 'recess 30 are a plurality of transversely spaced stiffener slots 58, including a plurality of transversely spaced lands 59 projecting forward from the face surface 60. The slots 58 are vertically aligned with the corresponding hooks 40 and 40' when clamped in the respective insert slots 38. Thus, when each looper hook 40 and 40' is received within the corresponding in¬ sert slot 38, each hook head or neck 42 fits within a corresponding stiffener slot 58, bearing against the face surface 60 between an opposing pair of lands 59. The stiffener slots 58 provide additional reinforcement for stabilizing the neck portions 42 of the hooks 40 and 40' .
11 In a preferred form of the invention, that is,""in a staggered needle cut pile tufting machine, the looper hooks 40 cooperatinσ with the rear needles 12 are iden¬ tical in construction to the looper hooks 40' which co-
5 operate with the front needles 11, except that the bills 44' of the looper hooks 40' are longer than the bills 44 by a length substantially equal to the offset longitudin¬ al spacing between the rows of front needles 11 and rear needles 12. In the preferred form of the invention, the
10 throats 47 of all of the loopers 40 and 40' are in trans¬ verse alignment, pursuant to the teaching in the US Card patent 4,003,321, for "CUT PILE APPARATUS FOR STAGGERED NEEDLE TUFTING MACHINE".
Cooperating with each of the looper hooks 40 and
15 40' is a conventional cut pile knife 62 (FIG. 1) which is adapted to be reciprocated in a conventional manner in synchronism with the receiprocation of the hook bar 20 for cooperation with the respective needles 11 and 12 to catch and cut the yarns 14 and 15 in order to form cut
20 pile loops, not shown.
The modular hook bars 20 are preferably made in sections abutting end-to-end, and the abutting- ends over¬ lap a corresponding bracket 22.
For ease Of assembly, and to maintain the uniform
25 hook slot gauge, each hook bar 20 may have mating, over¬ lapping and recessed end portions, as indicated by the line 64 in FIG. 1.
Referring now to the modification disclosed in FIGS. 5-9, FIG. 5 discloses a cross-section of a needle bar
30 assembly 70 made in accordance with this invention assembled in conventional multiple-needle tufting machines . The needle bar assembly 70 supports a plurality of uniform¬ ly spaced needles 71 in transverse alignment. It will be understood that the needle bar assembly 70 could support
35 needles staggered in two rows and offset from each other, as disclosed in FIG. 1, if desired.
The needle bar assembly 70 is vertically recip'ro- cated by conventional needle drive means, including a push rod 73 connected to the needle bar assembly 70. The push rod 73 vertically reciprocates the needle bar assembly 70 to cause the needles 71 to move between an upper position above the base fabric 75 (not shown) to a lower position (FIG. 5) penetrating the base fabric 75, so that the needles 71 will carry yarn 72 through the base fabric 75 to form loops of tufting therein, not shown. The base fabric 75 is supported upon a needle plate 76, for movement, by means, not shown, in the di¬ rection of the arrow of FIG. 5, that is longitudinal •from front-to-rear of the machine.
The looper apparatus 76 which cooperates with the needle 71 may be identical to that disclosed in FIGS. 1-4, or may be of any other conventional construction, and includes the looper hooks 78. Where cut pile is formed by the needles 71 and the corresponding looper hooks 78, a knife 80 is reciproσably supported to co- operate with each' hook 78 for cutting the seized loops, in a well-known manner.
The needle bar assembly 70 includes a continuous, elongated needle bar 82, having a front outside surface 83 and a bottom face surface 84. Formed co-extensively within the ne'edle bar 82 and opening through the bottom face 84 is an elongated recess 85, preferably rectangular in cross-section, so that the needle bar 82 has a sub¬ stantially inverted U-shaped cross-section.
The elongated recess 85 includes a top inner surface 86, a ear inner surface 87, and a front inner surface 88. Adapted to be received within the recess 85 is an elongated gauge member 90 having an elongated continuous head member or head wall 91 from which project, parallel to each other, a -plurality of uniformly longitudinally spaced lands or partition walls 92, defining insert slots 93.
Adapted to be received within each of the insert slots 93 is a clamp member 95, also having a T-shaped cross-section similar to each of the clamp members 50. Each clamp member 95 is provided with an elongated di- vider member 97/ terminating in a head or bearing flange 96 which projects heyond both sides of one edge* of the divider member 97 to form needle seats 98.
The width of each insert slot 93 is great enough to receive the thickness of the divider member 96 and the combined thicknesses of the shanks 100, preferably flat¬ tened, of the needles 71. As disclosed in the drawings, a pair of needles 71 are received in each insert slot 93 together with one clamp member 95.
The distance between the closed end 101 of each insert slot 93 and the front inner face 88 of the re¬ cess 85 is slightly greater than the width, or front-to- rear dimension of a needle shank 100 and the thickness, or front-to-rear dimension, of a corresponding clamp head 96. Formed in the front face 83 of the needle bar 82 are a plurality of threaded set screw holes 102. There is one set screw hole 102 for each insert slot 93, each set screw hole 102 being in the same vertical plane as the center line of each of the insert slots 93. As disclosed in FIGS. 6 and 9, the threaded holes 102 may be staggered, if desired, although they may also be in longitudinal alignment.
Each set screw hole 102 is adapted to threadedly re¬ ceive a set screw 104, which is adapted to extend from the front exterior surface 83 through the needle bar 82 and into the recess 85 to engage a bearing surface of a corresponding clamp head 96.
Thus, as each set screw 104 is tightened in its corresponding hole 102, it engages and presses the head 96 of the clamp member 95 rearward causing the seats 98 to bear against the front surfaces of the corresponding
needle shanks 100 and force them rearward into the -• corresponding insert slot 93 until the rear edges of the needle shanks 100 are forced against the corresponding surface 101 of the slot 93. This pressure by the clamp member 95 is transmitted through the gauge member 90 and against the rear inner surface 87 of the recess 85. In this manner, the needles 71 are securely locked or fixed within the needle bar 82.
Furthermore, since only one set screw 104 is need- ed for each clamp member 95, and each clamp member 95 clamps two needles 71, only half as many set screws 104 are required in comparison with conventional needle bar assemblies.
Accordingly, because of the reduced number of set screws 104 and the reduced number of insert slots 93, the needles 71 may be spaced closer together to provide a very fine needle gauge.
For the same reasons, because of the reduced number of set screws 55 in the apparatus disclosed in FIGS. 1-4, and the reduced number of insert slots 38, the hooks 40 and knives 62 may be spaced closer together to provide more narrow needle gauges than have heretofore been successfully used in multiple needle tufting machines. By virtue -of the utilization of the gauge members 35 and 90, and the clamp members 50 and 95, the corres¬ ponding set screws 55 and 104 will engage only the rela¬ tively broad clamp heads 52 and 96 respectively, and en¬ gage no part of the respective tufting element, that is the hook shank 41 or the needle shank 100. in the prior use of set screws, the ends of the set screws normally cut into the respective hook or needle shank to deface the respective tufting element or form burrs therein. With the above clamp members 50 and 95, there is a broader bearing engagement between the clamp members 50 and 95 and their respective hooks 41 and needle shanks 100, thereby providing greater pressure distribu¬ tion between the clamping force and the respective tufting
element. Such a feature not only reduces the possible defacement or damage to the respective tufting element, but also provides a more secure gripping action between the respective hooks and needles and their respective hook bars and needle bars.
In prior hook bars which are generally made in elongated sections, which overlap each other as dis¬ closed in FIGS. 1 and 4, crowding of the set screw holes 54 tends to weaken the walls of the set screw holes, particularly at the ends of the hook bar sections, thus, creating a definite limitation upon the spacing of the set screw holes 54 and therefore the fineness of the needle gauge. This problem is overcome by the reduced number of screw holes 54 in the hook bar 20. With the utilization of the clamp members 50 and 95 in the respective looper and needle bar assemblies, needle gauges have been obtained as fine as 1/16 of an inch.