Abstract:
A gated looper apparatus has an array of individually mounted pressurizable air cylinders with piston rods acting against biased slider bars in communication with looper gates. Baising elements are mounted external of pneumatic cylinders about slider bars with protective ferules to provide greater responsiveness and ease of maintenance.

Description:
RELATED U.S. APPLICATION DATA 
   This application claims the benefit of U.S. Provisional Application No. 60/649,505 filed Feb. 3, 2005 which is incorporated herein by reference. 

   FIELD OF THE INVENTION 
   The present invention relates to the manufacture of tufted fabrics, and particularly to an improved gate apparatus to allow a looper to tuft either loop pile or cut pile stitches. 
   BACKGROUND OF THE INVENTION 
   In the field of tufting, there have been a variety of efforts made to enable both cut pile and loop pile tufts or bights of yarn to be placed in the same row of stitches. In some instances, the structures utilized for this purpose did not allow effective control of the height of stitches and, for instance, the cut pile stitches might always be of greater height than the loop pile stitches. The use of pivoting gate structures on the loopers was proposed in Jolley, U.S. Pat. No. 4,134,347 and Crumbliss, U.S. Pat. No. 4,353,317. 
   Later sliding gate structures were proposed as typified by Bennett, U.S. Pat. No. 6,155,187. When properly implemented, sliding gate structures may provide rapid response and avoid moving the entire pneumatic activation assembly with the loopers. However, Bennett taught the use of internal biasing elements in pneumatic cylinders and the use of blocks of cylinders to improve efficiencies in assembly. In practice, the use of internal biasing elements limits the size and corresponding force that the biasing elements may provide. In turn, this limits the speed with which the gate can return to the open position after pressure to its corresponding pneumatic cylinder is stopped. Furthermore, the internal biasing elements are not visible to inspection and if rust beings to form due to moisture in the cylinder, for instance, there will be no way to detect the problem until performance degrades to the point where defective carpet patterns are produced, with resulting waste carpet and the need to replace an entire cylinder block rather than merely a spring or biasing element. 
   Finally, it is desirable to assemble the pneumatic cylinders used to operate the gates in a tight array to permit their use with fine gauge tufting machines. Constructing the cylinders in arrays of removable cylinders stacked four high in nearly vertical columns and designing corresponding gate structures permits this density to be achieved. 
   SUMMARY OF THE INVENTION 
   Therefore, it is a primary object of the invention to provide an improved sliding gate structure for use in tufting both loop pile and cut pile stitches from yarns seized by the same looper. 
   It is another object of the invention to provide a pneumatically activated sliding gate structure with external biasing means to return the gates to their open and unactivated positions. 
   It is yet another object of the invention to provide discrete pneumatic cylinders and biasing means so that a defective element may be replaced without the need for replacing an entire module or block of components. 
   It is still a further object of the invention to provide an array of pneumatic cylinders and corresponding activated sliding gates in a compact form so as to be effectively employed with narrow gauge needle configurations according to the present invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The particular features and objects of the invention as well as other advantages will be appreciated from the following description in connection with the drawings of an embodiment of the invention in which: 
       FIG. 1  is a sectional end view of a multiple needle tufting machine constructed for use with the sliding gate assembly of the present invention. 
       FIG. 2  is a sectional view of a representative pneumatic cylinder that may be adapted for use in the present invention. 
       FIG. 3A  is a perspective partial sectional view of an embodiment of two columns of four cylinders and the corresponding gates and loopers according to the present invention. 
       FIG. 3B  is a rear perspective view of the assembly of  FIG. 3A . 
       FIG. 4A  is a perspective partial sectional view of an embodiment of two columns of four cylinders and the corresponding gates and loopers according to the present invention. 
       FIG. 4B  is a rear perspective view of the assembly of  FIG. 4A . 
       FIG. 5  is an exploded rear perspective view of an embodiment of an eighteen column array of pneumatic cylinders and corresponding gates, loopers and related gauge components. 
       FIG. 6  is a side view of an embodiment of the invention in position on the rocker bar of a tufting machine. 
       FIG. 7  is a detailed exploded view of a slider and biasing spring according to a preferred embodiment of the invention. 
       FIG. 8A  is another embodiment of the invention in perspective view on the rocker bar. 
       FIG. 8B  is an exploded perspective view of the cylinder and slider assembly of the embodiment of  FIG. 8A . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  discloses a tufting machine  10  including transversely supported needle bar  12  which in turns supports a row of transversely spaced needles  14 . The needle bar carrier  11  is connected to push rod  16  adapted to be vertically reciprocated by a conventional needle drive mechanism, not shown. Front yarns  18  are supplied to the needles  14  through apertures  19  in the front yarn guide plate  20  from a source of yarn supply, not shown, such as yarn feed rolls, creels, or other known yarn supply means. Preferably the front yarns pass through a yarn feed pattern control mechanism  21  adapted to feed the appropriate length of individual yarns  18  to corresponding needles  14  in accordance with a pre-determined pattern. Any one of several pattern control mechanisms may be incorporated in the mechanism  21  such as those disclosed in U.S. Pat. Nos. 6,244,203 and 6,283,053, or earlier mechanisms, and typically attach to the head  26  of tufting machine  10 . 
   When needed, rear yarns may be correspondingly fed through apertures  23  in rear yarn guide plates  24  from another source or supply of yarns. If desired, the needle bar  12  may be slideably mounted and shifted by appropriate pattern control means in a well known manner, such as by cams, roller drives, or hydraulic shifters. 
   Supported upon a needle plate  32  and fixed to bed frame  33  are a plurality of straight rearward projecting transversely spaced needle plate fingers  34  extending between the vertical needle paths of the reciprocal needles  14 . The substrate or base fabric  35  is supported for longitudinal rearward movement over the needle plate  32 . The base fabric is drawn by conventional fabric feed mechanism or substrate drive such as a belt and pulley mechanism or servo motors powering spiked substrate drive rolls  27 ,  28 . 
   The needle drive mechanism, not shown, is designed to actuate push rod  16  to vertically reciprocate the needle bar  12  and to cause the needles  14  to simultaneously penetrate the substrate  35  far enough to carry the yarns  18  through the substrate  35  to form loops therein. After the loops are formed, the needles  14  are vertically withdrawn to their elevated retracted position disclosed in  FIG. 1 . 
   A looper apparatus  40  made in accordance with the invention and shown in greater detail in  FIG. 6 , includes a plurality of transversely spaced hooks  41 , there being at least one hook  41  for each needle  14  in the usual case. The hooks  41  are arranged so that the bill  42  of a hook  41  will cross and engage each needle  14  when the needle  14  is in its lowermost position and in a well known manner seize the yarn  18  and form a loop therein. The bills of the hooks  41  point forward opposite the direction of the fabric feed as indicated by the arrow  30 . Hooks  41  are mounted in hook bars as shown in greater detail in  FIGS. 3 through 6 , and secured at the upper end of rocker arm  47 . Any conventional means to oscillate the rocker arm  47  may be provided. In a customary embodiment, the lower end of the rocker arm  47  is clamped to laterally extending rock shaft  49 . Pivotably connected to the upper portion of the rocker arm  47  is one end of a connecting link  48  having its other end pivotably connected to a jack shaft rocker arm  25  (shown in  FIG. 6 ) mounted on a jack shaft  22  which has an oscillating motion imparted thereto by a drive means, such as a cam and lever apparatus in communication with the main drive shaft, so that the jack shaft  22  oscillates in timed relationship to the reciprocation of the needles  14 . The tufting machine  10  also incorporates a plurality of knives  36  which may cooperate with the hooks to cut selected loops to form cut pile tufts or bights of yarn as hereinafter described. The knives  36  may be mounted in knife blocks  37  and then mounted to a knife shaft rocker arm  39  which is clamped to knife shaft  38 . Oscillatory movement is imparted to the knife shaft  38  to conventionally drive the knives into engagement with one side of the respective hooks  41  as known in the art to provide a scissors-like cutting action. 
   In conventional tufting machine operation, the yarn feed pattern control mechanism  21  is programmed to feed selected yarns  18  at varying lengths in order to produce a desired high-low pattern of tufted bights of yarn. The yarns  18  can be selected from different colors or varying size or physical characteristics. Additional patterning capability may be provided by shifting the needle bar  12  as the substrate  35  moves in the direction of arrow  30  rearwardly through the machine  10 . The patterns formed on the substrate  35  appear on the bottom surface  45  while the upper surface  44  of the substrate  35  contains the back stitching necessary to permit needles  14  to move from one tufting location to another. After passing through the tufting zone, the backing fabric  35  is directed under a presser foot  22  and upward away from the tufting zone to provide space for the gated looper apparatus  40  of the present invention. 
   Central to the operation of gated loopers is the use of pneumatic cylinders  50  as shown in  FIG. 2 . Cylinder  50  has a rear portion with inlet opening  51  to receive pressurized gas, cylinder wall  53  defining a cylinder in which piston  52  may move reciprocally, and head  55  which stops the forward movement of piston  52  in response to the pneumatic force of the pressurized gas. A drive rod  54  extends from the piston  52  forward and out through the head  55  to a rod tip  59 . Piston seals  56  and rod seals  57  help insure the smooth movement of piston  52  within the cylinder without excess loss of pneumatic force. The tip  58  of head  55  is preferably threaded to enhance the ease of securely mounting cylinder  50 . Clippard Model EP2064-P10 air cylinders are the preferred pneumatic cylinders to utilize to practice the invention. 
     FIGS. 3 and 4  show a first embodiment of a sliding gate mechanism according to the invention. Pneumatic cylinders  50  are mounted to the rear of apertures  73  extending through rear mounting plate  61 . The forward ends  59  of rods  54  of pneumatic cylinders  50  engage with the rear of the sliders  75   a ,  75   b ,  75   c ,  75   d . Sliders  75  extend forward to detents  74 , through springs  70  and into slots  77 . Because cylinders  50  and sliders  75  are configured on four levels, upon entering slots  77 , the sliders  75  engage with a translation section such as compensating plates  78  in order that movement imparted by drive rods to sliders  75  will be translated to a plane of motion approximate the bottom of hook bills  42 . Compensating plates  78  engage looper clips  67  so that forward motion imparted by rod  54  is communicated to slider bar  75  and via compensating plate  78  to looper clip  67  which causes looper clip front end  68  to close the lip formed by the hook bill  42  of a corresponding hook  41 . When pneumatic pressure is released from cylinder  50 , the action of spring  70  pushing against front mounting plate  62  and detent  74  moves all of rod  54 , slider  75 , compensating plate  78 , and looper clip  67  rearward which again exposes the lip of loop hook  41  formed by hook bill  42 . 
   In  FIG. 3A , it can be seen that cylinders  50  corresponding to slider  75   c  and  75   d  are activated so that pistons  52  have pushed rods  54  forward thereby pushing sliders  75   c ,  75   d  forward and compressing springs  70   c  and  70   d . The corresponding compensating plates  78  are pushed forward, as are the looper clip fronts  68   c  and  68   d .  FIG. 3B  shows the reverse angle view of the same configuration. Accordingly, in this configuration when loop hooks  41  rock forward to seize loops of yarn from needles  14 , the loops of yarn seized on the first two hooks covered by looper clip fronts  68   c ,  68   d  will be seized and released while the yarns seized by hooks with hook bills not closed by sliders  68   a  and  68   b  will be retained on the lips formed by hook bills  42  and ultimately dragged into contact with knives  36  (shown in  FIG. 1 ) where the loops of yarn will be cut. Thus, loops of yarn seized over closed gated hooks will form loop pile bights and loops of yarn seized over open gated hooks will form cut pile bights of yarn on the face  45  of the carpet. 
     FIG. 4A  shows the same configuration of pneumatic cylinders  50 , slider bars  75 , compensating plates  78 , and looper clips  67 . However, in the illustrated configuration, it is sliders  75   a ,  75   b  and both sliders  75   c  that are activated by pneumatic pressure in corresponding cylinders  50  thereby closing the lips corresponding to hooks  41  that are matched with looper clip fronts  68   c ,  68   a  and  68   b . Thus, a stitch tufted with yarns seized by the six illustrated loopers will tuft four loop pile bights and two cut pile bights.  FIG. 4B  is a reverse angle illustration of the same configuration. Because the pattern of gated and ungated hooks can be changed with each stitch of the tufting machine, a wide variety of patterns of loop and cut pile bights of yarn may be produced. Because the springs  70  are not placed within cylinders  50  to act upon pistons  52  but instead are placed about the slider bars  75 , not only is it possible to use larger and more powerful springs, but any deterioration of spring function can be readily observed, and springs are not susceptible to retained moisture and rusting inside a confined cylinder space. The use of more powerful springs  70  provides faster return response to reopen the gated hooks at the conclusion of a stitch cycle, and permits faster operation of the tufting machine. 
     FIGS. 5 and 6  show an alternative preferred construction of gated loopers of the present invention. In this instance, rather than using slots  77  and compensating plates  78  to translate the movement of the cylinder rods  54  into the plane of the looper clips  67 , sliders  75  are constructed with a rear combination rod tip engaging portion  72  and detent, proceeding to a relatively straight spring bearing portion, then to a translation portion, and finally to a forward hook portion  71 . Forward hook portions  71  are designed to engage with rear hook portions  69  of looper clips  67 . The slider bars  75   a  connecting with pneumatic cylinders  50  are positioned along the top of the array of pneumatic cylinders in a four by eighteen configuration as illustrated in  FIG. 5 , translate the motion imparted by piston rods  54  downward as shown in slider bar  75   a . Similarly, the slider bar  75   d  which engages with a pneumatic cylinder at the bottom of the array translates the motion imparted by piston rod  54  upward. In the illustrated embodiment, the slider bars  75   b  and  75   c  which translate motion from piston rods  54  of intermediate rows of pneumatic cylinders translate that motion slightly downward, but less so than by the slider bars  75   a  for the cylinders  50  placed at the top of the array. 
   Pneumatic cylinders  50  have their threaded heads  58  fixed in rear openings  73  of rear mounting plate  61 . Piston rod ends  59  engage with slider bar rear tip engaging portions  72  which are received into the forward openings of apertures  73  of the rear mounting plate. The translation and front tip  71  portions of slider bar  75  extend forward through apertures  79  in front mounting plate  62 . On the relatively straight portions of the slider bars  75  intermediate front and rear mounting plates  61 ,  62  are mounted springs  70 . Slider tips  71  have upward facing lips that engage with downward facing lips of the rear  69  of looper clips  67 , such engagement preferably being within slots of clip guard  63 . Looper clips  67  extend forward into slots within hook blocks  73  so that a looper clip front end or gate  68  is adjacent to each hook  41  in the block. Pneumatic pressure applied to a cylinder  50  causes the piston rod  54  and corresponding rod end  59  to move forward thereby pushing corresponding slider ends  72  and sliders  75  with front end  71  forward and compressing the springs  70  on any activated slider  75  against the front mounting plate  62 . Slider front  71  pushes corresponding looper clip rear end  69  and looper clip  67  with gate  68  forward to cause gate  68  to cover the lip formed by hook bill  42  of its adjacent hook  41 . When pneumatic pressure in cylinder  50  is relaxed, the biasing force of compressed spring  70  on the activated slider bar  75  tends to return the looper clip  67 , slider bar  75  and piston rod  54  to their original positions, again opening the lips formed by the hook bills  42  and permitting yarns to be seized on the hooks  41  and brought into contact with an associated knife  36 . 
   Again, the placement of spring  70  external the slider bar  75  rather than internal the pneumatic cylinder  50  permits the use of more powerful springs and reduces maintenance issues associated with a gated looper apparatus. Furthermore, the use of individually attached cylinders  50  permits defective cylinders or other defective components to be replaced individually rather than requiring replacement of an entire array of components. This facilitates product service and reduces maintenance costs for both parts and labor. Front and rear mounting plates  61 ,  62  are positioned by spacer bolts  81  affixed in threaded apertures on the rear of front mounting plate  62  and extending rearward and bolts  80  extending through washers  82  and apertures in rear mounting plate and are received within spacer bolts  81 . Housing  66  is secured by bolts  83  through apertures  84  in the tops of front and rear mounting plates  61 ,  62 . The face  45  of tufted carpet may pass over housing  66  without interfering in any way with the operation of the gated looper apparatus. 
   The control of the pneumatic cylinders  50  and thus the gates  68  is preferably accomplished by a computer controlled array of valves with the number of valves corresponding to the number of cylinders, so that each hook  41  in a tufting machine and its corresponding looper clip  67  is controlled individually. In response to signals from the computer or controller, valves open and close communication between a compressor and air conduits communicating from the valves to each cylinder  50  in the arrays. When a valve is closed to prevent communication of pressurized air to a corresponding cylinder  50 , the valve vents the pressurized air so that spring  70  may return the gate apparatus to its inactivated open form, in which case the associated hook will tuft cut pile bights of yarn. 
   The guideway  43  is preferably made of aluminum which, in comparison to steel, will remove between about 35 to 60 pounds of weight from the looper apparatus over a 165″ to 195″ wide tufting machine. Additional weight savings are accomplished by utilizing aluminum and other lightweight metals for base  65  and support base  64 . By removing over 100 pounds of weight from the reciprocating looper apparatus, the tufting machine is subject to less vibration during operation and can be run at higher speeds. 
   A preferred slider and biasing spring is shown in  FIG. 7  with slider  175  having a front end  87  for translating motion to looper clips  67  and rear end  89  for engaging with drive rods of pneumatic cylinders. Over the rear end  89  is mounted ferule  90  having a base flange  92 , body  93  and lumen  91  to receive slider end  89 . A preferred biasing spring  70  preferably has a slightly tapered configuration from forward end  85  that rests on the base flange  92  to rearward end  86  and the pitch of the spring  70  is slightly less at the forward end. Forward end  85  fits over body  93  of ferule  90  and spring  70  is restrained in place on the slider  175  by a detent, here created by the insertion of pin  95  through aperture  96  at the rearward end  89  of slider  75 . The lessened pitch of spring  70  causes less deformation of the spring through the many repetitive cycles of compression and expansion. In addition ferule  90  protects spring  70  from uneven wear from repeated friction on the rearward end of slider  75 . Additional weight savings may also be accomplished by cut outs in slider  175  as shown in phantom. 
     FIG. 8A  shows an alternative embodiment of the invention in which the columns of cylinders are stacked at a slight angle to the vertical. These are referred to as substantially vertical offset columns. In this fashion, it is not necessary to have a transition section as is required when the column of cylinders  50  is entirely vertical. Cylinders  50  are screwed into openings on rear mounting plate which covers sliders  175   a ,  175   b ,  175   c ,  175   d  each configured with slightly different rear portion to connect at the appropriate height to the forward ends  59  of pneumatic cylinders  50  at an appropriate height. Sliders  175   a ,  175   b ,  175   c ,  175   d  engage with the rear of looper clips  68  within guideway  65 . The slider connections are covered by housing cover  66  which helps direct tufted fabric over the pneumatic gated looper assembly. An exploded view of the structure is shown in  FIG. 8B  more clearly showing a different rear end  89  positioning of sliders  175   a ,  175   b ,  175   c ,  175   d.    
   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.