Patent Publication Number: US-10781544-B2

Title: Quilting machine

Description:
FIELD OF THE INVENTION 
     This invention relates to quilting, and particularly, to high-speed quilting machines. 
     BACKGROUND 
     Quilting is a sewing process by which layers of textile material and/or other fabrics are joined to produce compressible panels that may be both decorative and functional. The manufacture of certain products, such as mattress covers, involves the application of large-scale quilting processes. These large-scale quilting processes typically use high-speed multi-needle quilting machines to form a series of cover panels along webs of the multiple-layered materials. Large-scale quilting processes typically use chain-stitch sewing heads that produce resilient stitch chains which are supplied by large spools of thread. 
     For quilting patterns that are not continuous, when the quilter finishes one pattern, the quilt is moved relative to the sewing heads to place the stitch forming elements in the starting position of the new pattern. To avoid having loose threads strung between the end of the previous pattern and the beginning of the new pattern, which would require manual trimming, the needle and/or looper threads may be cut after the previous pattern has been stitched. However, cutting the threads also increases the likelihood that the needle and/or looper will become unthreaded. 
     When the thread is cut, there should be sufficient thread length remaining to prevent unthreading of the needle and/or looper, but not so much thread length that a tail of thread is left sticking out from the finished quilt. If the thread is too short, the needle or looper may become unthreaded, forcing a shutdown of the quilting machine until it can be rethreaded. Conversely, if the thread is too long, the resulting quilt may require manual trimming before it can be used. If the looper thread has insufficient length, the needle thread may also have difficulties picking up the looper thread at the start of the next pattern, thereby causing missed stitches. 
     Thus, improved methods, apparatuses, and computer program products are needed for producing quilted products that allow threads to be cut between patterns without the sewing head becoming unthreaded or a defective quilt being produced due to missed stitches at the start of the next pattern. 
     SUMMARY 
     In an embodiment of the invention, a quilting machine is provided. The quilting machine includes a looper from which thread is provided to form stitches in a web, and an adjuster having a first position and a second position. When the adjuster is moved from the first position to the second position, the adjuster captures the thread at a point between the looper and a last formed stitch in the web, and pulls a predetermined amount of thread from the looper. 
     In another embodiment of the invention, a method of quilting the web is provided. The method includes providing the thread from the looper to form stitches in the web, capturing the thread at the point between the looper and the last formed stitch in the web, and pulling the predetermined amount of thread from the looper. 
     In another embodiment of the invention, a computer program product is provided for quilting webs that includes a non-transitory computer-readable storage medium. The storage medium includes program code that is configured, when executed by one or more processors, to cause the quilting machine to provide the thread from the looper to form stitches in the web, capture the thread at the point between the looper and the last formed stitch in the web, and pull the predetermined amount of thread from the looper. 
     In another embodiment of the invention, a quilting machine is provided that includes a controller configured to control operation of the quilting machine, a thread tension monitor configured to monitor a tension of a thread using a drop wire and provide a first signal to the controller indicative of the tension in the thread based on a movement of the drop wire, and a lift arm configured to selectively restrict the movement of the drop wire in response to a second signal from the controller. 
     In another embodiment of the invention, another method of quilting the web using the quilting machine is provided. The method includes monitoring the tension of the thread using the drop wire, providing the first signal to the controller indicative of the tension in the thread based on the movement of the drop wire, and restricting the movement of the drop wire using the lift arm that is responsive to the second signal from the controller. 
     In another embodiment of the invention, another computer program product for controlling the quilting machine is provided. The computer program product comprises a non-transitory computer-readable storage medium and program code stored on the non-transitory computer-readable storage medium. When executed by one or more processors of the quilting machine, the program code causes the quilting machine to monitor the tension of the thread using the drop wire that provides the first signal to the one or more processors indicative of the tension in the thread based on the movement of the drop wire, and restrict the movement of the drop wire using the lift arm. 
     The above summary may present a simplified overview of some embodiments of the invention to provide a basic understanding of certain aspects of the invention discussed herein. The summary is not intended to provide an extensive overview of the invention, nor is it intended to identify any key or critical elements, or delineate the scope of the invention. The sole purpose of the summary is merely to present some concepts in a simplified form as an introduction to the detailed description presented below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various embodiments of the invention and, together with the general description of the invention given above, and the detailed description of the embodiments given below, serve to explain the embodiments of the invention. 
         FIG. 1  is a perspective view of an exemplary quilting machine in accordance with an embodiment of the invention. 
         FIG. 2  is a cross-sectional view of the quilting machine of  FIG. 1  showing a web positioning system comprising a plurality of rollers mounted to a carriage, and a plurality of sewing heads each including a needle assembly and a looper assembly. 
         FIGS. 3 and 4  are diagrammatical views of the needle and looper assemblies of  FIG. 2  from the side and the front of the assemblies. 
         FIGS. 5 and 6  are diagrammatical views of one of the needle assemblies of  FIGS. 3 and 4  showing additional details of the needle assembly. 
         FIG. 7  is a perspective view of a portion of the looper assembly of  FIGS. 3 and 4  showing a looper, a retainer, and an adjuster assembly. 
         FIGS. 8A and 8B  are perspective views of another portion of the looper assembly of  FIGS. 3 and 4  showing a looper thread handler. 
         FIGS. 9A-9G  are perspective views of the stitch forming elements of the needle and looper assemblies illustrating a stitching process. 
         FIGS. 9H-9L  are perspective views of the stitch forming elements of  FIGS. 9A-9G  illustrating a thread cutting process. 
         FIGS. 9M-9Q  are perspective views of the stitch forming elements of  FIGS. 9A-9L  illustrating a process for resuming stitching. 
         FIGS. 10A-10Q  are top-down views showing the relative positions of the stitch forming elements in each of  FIGS. 9A-9Q , respectively. 
         FIG. 11  is a flow-chart illustrating the thread cutting process of  FIGS. 9H-9L . 
         FIG. 12  is a flow-chart illustrating the process of resuming stitching of  FIGS. 9M-9Q . 
         FIG. 13  is a diagrammatic view of an exemplary controller that may be used to execute the processes of  FIGS. 11 and 12 . 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     Embodiments of the invention may be implemented on a single or multi-needle quilting machine. Each sewing head of the quilting machine includes a looper assembly. The looper assembly includes a cutter (e.g., a retainer having a cutting edge), a looper having an eye from which looper thread is provided to form chain stitches, and an adjuster assembly. The adjuster assembly is configured to, in response to activation by a controller of the quilting machine, extend an adjuster toward the looper thread at a point between the eye of the looper and where the looper thread crosses the retainer. In response to the adjuster being moved (e.g., retracted or extended, as the case may be), the looper thread is pulled away from the looper, thereby drawing a predetermined amount of thread from the looper. The adjuster assembly thereby provides a controlled length of thread between the looper and the cutter. This length of thread provides a tail of sufficient length to reduce the likelihood that the looper will become unthreaded after the looper thread has been cut. The looper assembly may also include an air nozzle that provides air to the looper to assist the release of the thread from the adjuster after the thread has been cut, and/or to position the thread for starting the next pattern. 
     In another aspect of the invention, each of the needle and looper assemblies may include a thread tensioner and a thread tension monitor having a lift arm. The thread tension monitor may be configured to monitor the tension in the respective needle or looper thread and generate a signal that shuts down the quilting machine in response to detecting a loss of tension. The lift arm may be activated by the controller to disable the thread tension monitor so that a loss of tension in a sewing head does not shut down the quilting machine. The needle assemblies may also include a thread clamp that clamps the needle thread in response to a signal from the controller, thereby enabling the controller to increase tension on each needle assembly independently of the tension provided by the tensioner. The lift arm and thread clamp may facilitate deactivation of one or more sewing heads by the controller. The controller may deactivate the one or more sewing heads, for example, when the quilting machine is used to quilt a pattern that does not require use of the deactivated sewing heads. 
       FIGS. 1 and 2  provide a perspective view and a cross-section view along line  2 , respectively, of a multi-needle quilting machine  10  in accordance with an embodiment of the invention. The machine  10  may be used, for example, to quilt webs of multi-layered material, such as used in the manufacture of mattress covers. The machine  10  is built on a frame  12  having an upstream or input end  14  located proximate to a lower portion of frame  12 , and a downstream or output end  16  proximate to an upper portion of frame  12 . A web  18  comprising multiple layers of material (e.g., a facing layer, a filler layer, and a backing layer) is provided from a supply station  20  and enters the machine  10  at the input end  14 . The machine  10  includes at least one motor  22  that provides a source of motive power for operating the machine  10 . This motive power may be provided to various components of machine  10  through one or more drive systems, such as drive system  24 . Exemplary methods and systems for providing motive power to quilting machines are described in more detail in U.S. Pat. Nos. 5,154,130 and 7,143,705, the disclosures of which are incorporated by reference herein in their entireties. 
     The input end  14  of machine  10  may include one or more entry rollers  26 - 29  configured to receive the web  18 . The entry rollers  26 - 29  may comprise idler rollers that direct the web  18  to a set of upstream drive rollers  30 - 33 . The upstream drive rollers  30 - 33  are configured to pull the web into the input end  14  of machine  10  and provide the web  18  to a sewing area. A set of downstream drive rollers  34 - 38  located at the output end  16  of machine  10  pull the web  18  through the sewing area and discharge the quilted web  18  into a take-up station  40 . Each of the rollers  26 - 38  may be rotatably mounted to a carriage  42  that is configured to move laterally relative to the frame  12  of machine  10  in response to signals from a controller  44 . The controller  44  can control the lateral position of the web  18  in the sewing area by adjusting the position of the carriage  42 . 
     The web  18  passes between a presser plate  46  and a needle plate  48  that define a quilting plane  50  in the sewing area between the upstream drive rollers  30 - 33  and downstream drive rollers  29 - 38 . The drive rollers  30 - 38  may operate cooperatively to provide tension to and position the portion of the web  18  between the presser and needle plates  46 ,  48 . To this end, the drive rollers  30 - 38  may be linked to drive motors and/or brakes responsive to signals from the controller  44 . The controller  44  may control both the movement and tension of the web  18  through the machine  10 , particularly in the quilting plane  50 , to position the web  18  both longitudinally and laterally within a quilting plane  50  using the drive rollers  30 - 38  and by adjusting the position of the carriage  42 . 
     The location and movement of the components of machine  10  may be described using a coordinate system  52  that includes an x-axis  54 , a y-axis  56 , and a z-axis  58 . The x-axis  54  of coordinate system  52  is aligned with the quilting plane  50  in a direction generally parallel to the longitudinal movement of the web  18  between the presser and needle plates  46 ,  48 . The y-axis  56  of coordinate system  52  is aligned with the quilting plane  50  in a direction perpendicular to the x-axis  54  and parallel to the transverse movement of the web  18  provided by lateral movement of the carriage  42 . The z-axis  58  of coordinate system  52  is perpendicular to both the x-axis  54  and the y-axis  56 , and is normal to the quilting plane  50 . 
     One or more needle assemblies  60  and looper assemblies  62  may be mounted to a common support structure  64  that couples the assemblies  60 ,  62  to the frame  12 . The support structure  64  locates each needle assembly  60  on a needle facing side of presser plate  46 , and locates each looper assembly  62  on a looper facing side of needle plate  48 . Each of the needle assemblies  60  is provided with thread from a respective needle thread spool  66 , and each of the looper assemblies  62  is provided with thread from respective looper thread spool  68 . Each needle assembly  60  is located opposite a corresponding looper assembly  62  to form a sewing head  70 . The needle and looper assemblies  60 ,  62  of each sewing head  70  may be configured to work cooperatively to form a series of double lock chain stitches in the web  18  using the thread provided by the needle and looper thread spools  66 ,  68 . 
     In an embodiment of the invention, a plurality of sewing heads  70  are mounted to the support structure  64  in one or more rows (e.g., two rows), with each row including a number of sewing heads  70  (e.g., seven or eight) spaced laterally along the row. The lateral spacing in each row may be selected so that each sewing head  70  is offset from its neighboring sewing head along the y-axis  56  by a fixed distance d 1  (e.g., 12 inches) corresponding to twice the minimum distance between quilted patterns that can be produced by the machine  10 . In addition, the sewing heads  70  in adjacent rows may be offset from each other along the y-axis  56  by another fixed distance d 2  (e.g., 6 inches) corresponding to the minimum distance between quilted patterns that can be produced by the machine  10 . The rows of sewing heads  70  may be arranged longitudinally so that each row is offset from its neighboring rows along the x-axis  54  by the fixed distance d 2 . This spacing may enable the machine  10  to simultaneously produce patterns having the minimum spacing by synchronous operation of the sewing heads  70 . 
     The rollers  26 - 38  and carriage  42  may be configured to provide bi-directional movement of the web  18  relative to the sewing heads  70  in both the x-axis  54  and y-axis  56 . In operation, the controller  44  may cause the machine  10  to sequentially move the web  18  back and forth in both the longitudinal (x-axis  54 ) and transverse (y-axis  56 ) directions relative to the sewing heads  70  to quilt 360-degree patterns on the web  18 . Material accumulators may be used to facilitate moving the portion of the web  18  passing between the presser plate  46  and needle plate  48  in forward and reverse directions by the drive rollers  30 - 38  without changing the direction of the entire length of the web  18 . With this structure, the controller  44  can move the web  18  longitudinally in a forward or reverse direction using the drive rollers  30 - 38 , back and forth transversely by moving the carriage  42 , and selectively switch individual sewing heads  70  on and off in various combinations and sequences of combinations to stitch a variety of quilting patterns. 
     Although movement of the sewing head  70  relative to the web  18  is described herein as being accomplished by holding the sewing heads  70  stationary and moving the web  18  relative to the frame  12 , it should be understood this relative movement could also be obtained by moving the sewing heads  70  relative to the frame  12  while holding the web  18  stationary, or by a combination of movements of the sewing heads  70  and web  18  relative to the frame  12  of machine  10 . Thus, embodiments of the invention are not limited to machines  10  in which the sewing heads  70  are held stationary while the web  18  moves relative to the frame  12 . 
       FIGS. 3 and 4  present respective front and side views of two sewing heads  70 , one on each of two longitudinally spaced rows. The needle assembly  60  of each sewing head  70  is configured to reciprocate a needle  72  in a generally linear path along an axis  74  thereof that is perpendicular to the quilting plane  50 . The corresponding looper assembly  62  is configured to oscillate a looper  76  in a plane that is generally perpendicular to the quilting plane  50  and which intersects the path of the needle  72 . The presser plate  46  is coupled to a presser drive shaft  78  by a presser linkage  80  that moves the presser plate  46  linearly along the z-axis  58  to selectively compress and release the web  18  in response to rotation of the presser drive shaft  78 . 
     Each of the needle assemblies  60  receives thread from its corresponding needle thread spool  66  through a needle thread handler  82 . The needle plate  48  supports the web  18  as patterns are stitched on the web  18  to form a quilt. The presser plate  46  and needle plate  48  each include a plurality of respective needle holes  84 ,  86  that are aligned vertically to allow the needle  72  to pass through the web  18  and extend below the needle plate  48 . The presser plate  46  may be moved toward the needle plate  48 , thereby pressing the web  18  against the needle plate  48  to hold the web  18  as the needle  72  is extended through the web  18 , and be moved up to facilitate movement of the web  18 . 
     The looper assembly  62  of each sewing head  70  is positioned beneath the corresponding needle assembly  60 . Each looper assembly  62  includes the looper  76 , an adjuster assembly  88 , and a retainer  90  ( FIG. 7 ), and receives thread from the looper thread spool  68  through a looper thread handler  92 . The looper assemblies  62  are transversely spaced on looper shafts  94 , and the looper shafts  94  longitudinally spaced on the frame  12  of machine  10  so that each looper  76  is in a generally vertical alignment with the needle  72  of the corresponding needle assembly  60 . The looper shafts  94  are pivotally mounted to the frame  12  and configured to oscillate about an axis  96  of the looper shaft  94  synchronously with the reciprocal movement of the needle  72 . This synchronous oscillation causes the loopers  76  to reciprocate in a vertical plane generally perpendicular to the quilting plane  50  and parallel to the movement of the needle  72 . 
     Referring now to  FIGS. 5 and 6 , and with continued reference to  FIGS. 3 and 4 , each needle assembly  60  includes the needle thread handler  82 , a sub-frame  98 , a needle drive  100 , and a needle holder  102  that holds the needle  72 . The sub-frame  98  may be rigidly mounted to, or be a part of, the support structure  64  and provides mounting points for each of the other components of the needle assembly  60 . 
     The needle drive  100  includes a coupling device  104 , an output pulley  106 , an idler pulley  108 , a crank pulley  110 , a connecting rod  112 , a reciprocating shaft  114 , and a timing belt  116 . The coupling device  104  may include a clutch or other mechanism that is configured to selectively engage and disengage the output pulley  106  with the drive system  24  in response to signals from the controller  44 . The coupling device  104  may thereby enable the controller  44  to independently activate and deactivate operation of each needle assembly  60 . Exemplary coupling devices for use in quilting machines are described in more detail in U.S. Pat. No. 7,143,705. 
     The output pulley  106  is coupled to the crank pulley  110  by the timing belt  116 , which drives the crank pulley  110  in response to rotation of the output pulley  106 . The idler pulley  108  provides tension to the timing belt  116  to maintain the timing belt  116  in positive engagement with the output pulley  106  and crank pulley  110 . 
     The crank pulley  110  includes a pin  118  offset radially from the crank pulley&#39;s center of rotation that is rotatably connected to a proximal end  120  of connecting rod  112 . A distal end  122  of connecting rod  112  is rotatably connected to a pin  124  extending from the reciprocating shaft  114 , which is an extension of or otherwise coupled to the needle holder  102 . The needle drive  100  is thereby configured to reciprocate the needle holder  102  in a generally linear path perpendicular to the quilting plane  50  in response to rotation of the output pulley  106 . To reduce variations in the tension on a needle thread  126  as the needle  72  is reciprocated up and down to form stitches, the reciprocating shaft  114  may include a thread guide  128  through which the thread  126  passes on the way to needle  72  from the needle thread handler  82 . 
     The needle thread handler  82  includes a thread clamp  130 , a thread tensioner  132 , and a thread tension monitor  134 . The thread clamp  130  includes an input thread guide  136 , a clamping mechanism  138 , and an output thread guide  140 . The clamping mechanism  138  may include a reciprocating member  142  coupled to an actuator  144 , and a stationary member  146 . The reciprocating member  142  includes a clamping surface  148  that faces and is generally parallel to a corresponding clamping surface  150  of the stationary member  146 . The input thread guide  136  is configured to receive the needle thread  126  from needle thread spool  66 , and operates in cooperation with the output thread guide  140  to locate the needle thread  126  between the clamping surfaces  148 ,  150  of the reciprocating and stationary members  142 ,  146 . 
     The actuator  144  of clamping mechanism  138  is configured to selectively position the reciprocating member  142  in a retracted position or an extended position. When the reciprocating member  142  is in the retracted position, a gap may exist between the clamping surface  148  of reciprocating member  142  and the clamping surface  150  of stationary member  146 . When the reciprocating member  142  is in the extended position, the gap between the clamping surfaces  148 ,  150  may be reduced, thereby compressing the needle thread  126  between the clamping surfaces  148 ,  150  with sufficient force to prevent the needle thread from moving freely through the thread clamp  130 . 
     The position of one or more of the reciprocating and stationary members  142 ,  146  of clamping mechanism  138  may be adjustable, e.g., by using a threaded nut to adjust the position of the reciprocating member  142  relative to the actuator  144  and/or the position of the stationary member  146  relative to sub-frame  98 . This adjustability of the clamping mechanism  138  may enable an operator to set the size of the gap and/or the clamping pressure of the clamping mechanism  138  to a desired value. 
     The thread tensioner  132  may include an actuator  152 , an elastic member  154 , a stationary member  156 , and a movable member  158 . The stationary and movable members  156 ,  158  include mutually opposed friction surfaces  160 ,  162 . The movable member  158  may be coupled to a guide rod  164  that is in turn coupled to the elastic member  154  by a keeper  166 . The keeper  166  may include a knurled nut or other suitable fastener that is attached to a distal end of the guide rod  164 , and provides a surface against which the elastic member  154  presses when compressed. The tension provided by the elastic member  154  may be set by adjusting the position of the keeper  166  on the guide rod  164 . For example, for embodiments including the knurled nut, the distal end of guide rod  164  may be threaded, and the position of the keeper  166  may be adjusted by rotating the knurled nut relative to the threaded end until the desired tension is achieved. A jam nut may then be tightened against the knurled nut to lock the keeper  166  in position. 
     The elastic member  154  may comprise a spring that is coaxially located about the guide rod  164  and configured to urge the movable member  158  toward the stationary member  156 . The needle thread  126  is located by one or more thread guides  168 ,  170  that align the needle thread  126  between the friction surfaces  160 ,  162 . When urged into contact by the elastic member  154 , the friction surfaces  160 ,  162  apply friction to the needle thread  126  that generates tension as the thread is drawn downstream from the thread tensioner  132  to the needle  72 . In response to activation by the controller  44 , the actuator  152  applies force to the guide rod  164  that reduces the tension provided by the elastic member  154  (e.g., by moving the keeper  166  away from the movable member  158 ), which in turn may reduce tension on the needle thread  126 . The thread tensioner  132  may be adjustable to control the tension on the needle thread  126 , for example, by adjusting the position of the keeper  166  so that the elastic member  156  applies varying amounts of pressure on the movable member  158 . 
     The needle thread tensioner  132  may provide a desired thread tension in an active state, and minimal or no tension in an inactive state. The controller  44  may cycle the needle thread tensioner  132  between the active and inactive states through activation of the actuator  152  by, for example, selectively applying pneumatic pressure to the actuator  152  to switch between a tension state during which the set tension is applied to the needle thread  126 , and a release state during which no tension or minimum tension is applied to needle thread  126 . 
     The thread tension monitor  134  includes one or more (e.g., three) fixed thread guides  172 - 174  that define a travel path  176  for the needle thread  126 , a drop wire  178  coupled to a switch and having an eyelet  180 , and a lift arm  182  coupled to an actuator  184 . In operation, the needle thread  126  may be threaded through the fixed thread guides  172 - 174  of thread tension monitor  134  and the eyelet  180  of drop wire  178 . When the needle thread  126  is under tension, the thread urges the eyelet  180  to remain generally within or proximate to the travel path  176  defined by the fixed thread guides  172 - 174 , e.g., between thread guides  172 ,  173 . The drop wire  178  may be biased (e.g., by gravity) to pivot in a direction that would move the eyelet  180  out of the travel path  176  absent tension from the needle thread  126 . In response to the drop wire  178  pivoting beyond a predetermined angle indicative of a loss of tension in the needle thread  126 , the switch may change from a state indicative of sufficient tension (e.g., an open state) to a state indicative of a lack of sufficient tension (e.g., a closed state). A lack of tension on the needle thread  126  may indicate the thread has come loose from the needle  72 , broken, or run out. Thus, the machine  10  may be configured to halt operation in response to detecting the change of state in the switch indicating the lack of sufficient tension on the needle thread  126 . 
     The lift arm  182  and actuator  184  are configured so that when the sewing head  70  is operational, the lift arm  182  is normally held in a position that does not obstruct the pivoting movement of the drop wire  178 . In this condition, a loss of tension on the needle thread  126  allows the drop wire  178  to pivot out of the travel path  176  and trip the switch. If a pattern is being quilted that does not require the use of all the sewing heads  70  of machine  10 , the unneeded sewing heads  70  may be taken off line. In this scenario, the controller  44  may cause the actuator  184  to position the lift arm  182  on the off-line sewing heads  70  so that the lift arm  182  obstructs the pivoting movement of the drop wire  178 . In this condition, a lack of tension on the needle thread  126  will not cause the drop wire  178  to pivot out of the travel path  176  due to the lift arm obstructing the pivoting movement of the drop wire  178 . The actuated lift arm  182  may thereby prevent an inadvertent shutdown of the machine  10  in the event the needle thread  126  of an inactive sewing head  70  comes loose or during periods of operation when the tension on the needle thread  126  is purposefully low. 
       FIG. 7  depicts a portion of the looper assembly  62  including the looper  76 , the adjuster assembly  88 , and the retainer  90 . In an embodiment of the invention, the looper assembly  62  may also include an optional air nozzle  185  configured to direct air  187  at the looper  76 . The looper  76  includes a needle guard  186  and a holder  188  that couples the looper  76  to the looper shaft  94 . The needle guard  186  is configured to prevent the descending needle  72  from deflecting away from a needle facing side  190  of the advancing looper  76 . The needle guard  186  thereby increases the likelihood that the descending needle  72  stays on the needle facing side  190  of looper  76  as compared to looper systems lacking this feature. Keeping the needle  72  on the needle facing side  190  of looper  76  may aid the looper  76  picking up the needle thread  126  and thereby reduce the probability of a skipped stitch. 
     The looper  76  further includes a hook  192  having a tip  194  at a forward end thereof, and a base  196  at a rearward end thereof from which the hook  192  extends. The hook  192  includes a longitudinal bore or channel that connects an opening  198  at the back or rearward side of the looper  76  with an opening or eye  200  ( FIG. 9A ) at the tip  194 . Looper thread  202  from the looper thread spool  68  enters the opening  198  in the back of the looper  76  and emerges from the eye  200  of looper  76 . The air nozzle  185  may be configured to blow or puff the air  187  at the opening  198  so that at least a portion of the air  187  flows through the bore and out the eye  200  of looper  76 . The flow of air out of the eye  200  and/or around the hook  192  may be used to urge the looper thread  202  to extend outward away from the eye  200  of looper  76  or otherwise locate the thread  202 . 
     The base  196  of looper  76  may include a hole configured to receive the needle guard  186  and a set screw  204  that secures the needle guard  186  within the hole. The base  196  of looper  76  may be secured to the looper holder  188  by a peg (not shown) that extends from the bottom of the base  196  for insertion into a hole in the looper holder  188 . Set screws  205 ,  206  may be used to secure the base  196  of looper  76  to the looper holder  188 . The set screws  204 - 206  may enable the positions of the base  196  of looper  76  and/or needle guard  186  to be adjusted so that the looper  76  and/or needle guard  186  have a proper orientation with respect to the needle  72 . 
     The adjuster assembly  88  includes an adjuster  210 , a base  212  having a channel  214 , a linkage  216 , and an actuator  218 . The adjuster  210  may comprise a strip of sheet metal having a catch  220  (e.g., a hook) at a forward end of the strip and a post  222  that projects from a rearward end of the strip. When extended, the catch  220  may be configured to engage the looper thread  202  so that upon retraction of the adjuster  210 , the catch  220  pulls a predetermined amount of looper thread  202  from the eye  200  of looper  76 . The linkage  216  may comprise a generally L-shaped member having two arms  224 ,  226  that meet at an angle (e.g., a right angle) to form an apex  228 . The linkage  216  is pivotally mounted to the base  212  at the apex  228 , and includes a slot  230  in the end of arm  224 , and a slot (not shown) in the end of arm  226 . Although depicted as pulling the predetermined amount of looper thread  202  upon retraction, embodiments of the invention are not limited to this configuration. For example, in an alternative embodiment, the adjuster assembly  88  could be configured to pull the predetermined amount of looper thread  202  from the looper  76  by extending the adjuster  210 . In this alternative embodiment, the catch  220  may be provided by a notch in the adjuster  210  rather than a hook, and the adjuster assembly  88  and/or the cutting edge  256  may be positioned on an opposite side of the looper  76  than as depicted in  FIGS. 9A and 10A . 
     The post  222  of adjuster  210  is in pivoting/sliding engagement with the slot  230  in arm  224  and the actuator  218  is in pivoting/sliding engagement with the slot in arm  226  so that the adjuster  210  is moved (e.g., extended and/or retracted) in response to a corresponding movement of the actuator  218 . The adjuster  210  may be held in the channel  214  by a plate  234  having a slot  236  through which the post  222  of adjuster  210  extends to engage the slot  230  of arm  224 . The plate  234  may be held in place against the base  212  by one or more fasteners  238 . The adjuster assembly  88  may be configured so that when the adjuster  210  is extended, it passes between the looper  76  and the looper facing side of the needle plate  48  to hook the looper thread  202 . When retracted, the adjuster  210  may pull the looper thread  202  to create a predetermined amount of slack in the looper thread  202  between the eye  200  of looper  76  and the last stitch formed in the web  18 . 
     As best shown in  FIG. 10A , and with continued reference to  FIG. 7 , the retainer  90  may include a notch  246  formed by the vertex of a tine  248  and a lobe  250  at a forward end of retainer  90 , and a recessed portion  254  formed on a looper facing side of the retainer  90 . The recessed portion  254  of retainer  90  may include a cutting edge  256  suitable for cutting one or more of the needle thread  126  or looper thread  202 . A rearward end of retainer  90  may form a bracket that couples the retainer  90  to a rigid bar  260 . The retainers  90  of the looper assemblies  62  corresponding to each row of sewing heads  70  may be ganged together by corresponding rigid bars  260 , e.g. one bar  260  per row. The retainers  90  may be moved synchronously by the rigid bar  260  in a closed loop path about the needle hole  86  of needle plate  48  in a plane that is substantially perpendicular to the path of the needle  72  and which intersects the vertical plane defined by the reciprocating angular movement of looper  76 . 
       FIGS. 8A and 8B  depict a pair of looper thread handlers  92  each in a different state. Each looper thread handler  92  includes a thread tensioner  262 , a thread tension monitor  264 , and a pull-off mechanism  266  that are coupled to the support structure  64  by a mounting plate  268 . In the depicted embodiment, the pull-off mechanism  266  is shared by a plurality of looper thread handlers  92  (e.g., two) mounted to the mounting plate  268 . However, embodiments of the invention may include looper thread handlers  92  that each have their own pull-off mechanism  266 , and the invention is not limited to looper thread handlers  92  that share a pull-off mechanism  266  or mounting plate  268 . 
     The thread tensioner  262  includes an actuator  272 , an elastic member  274 , a stationary member  276 , and a movable member  278 . The stationary and movable members  276 ,  278  include mutually opposing friction surfaces (not visible) that are configured to resist movement of the looper thread  202  when the friction surfaces are urged into facing engagement by the elastic member  274  in a similar manner as described above with respect to the thread tensioner  132  of needle thread handler  82 . 
     The movable member  278  may be coupled to the actuator  272  and biased toward the stationary member  276  by the elastic member  274  so that the friction surfaces selectively provide tension to the looper thread  202 . The thread tensioner  262  may provide a desired thread tension in an active state, and minimal or no tension in an inactive state. The controller  44  may cycle the thread tensioner  262  between active and inactive states through activation of the actuator  272  by, for example, selectively applying pneumatic pressure to the actuator  272 . This application of pneumatic pressure may cause the thread tensioner  262  to switch between a tension state during which the set tension is applied to the looper thread  202  and a release state during which essentially no tension or minimum tension is applied to the looper thread  202 . 
     The looper thread  202  may be received from the looper thread spool  68  and directed to the thread tensioner  262  by one or more thread guides  270 ,  271 . After leaving the thread tensioner  262 , the looper thread  202  may pass through the thread tension monitor  264  and pull-off mechanism  266  before being provided to the respective looper  76 . Although the thread tension monitor  264  is shown as being upstream of the pull-off mechanism  266  in  FIGS. 8A and 8B , the invention is not so limited, and embodiments of the invention may include looper thread handlers  92  having the thread tension monitor  264  located downstream of the pull-off mechanism  266 . 
     The thread tension monitor  264  of looper thread handler  92  may be configured similarly to the thread tension monitor  134  of needle thread handler  82 , and includes one or more (e.g., three) fixed thread guides  284 - 286  that define a travel path  290  for the looper thread  202 . The thread tension monitor  264  may further include a drop wire  292  coupled to a switch and having an eyelet  294 , and a lift arm  296  coupled to an actuator  298 . In operation, the looper thread  202  may be threaded through the fixed thread guides  284 - 286  of thread tension monitor  264  and the eyelet  294  of drop wire  292 . When the looper thread  202  is under tension, it urges the eyelet  294  to remain generally within or proximate to the travel path  290  defined by the fixed thread guides  284 - 286 . The drop wire  292  may be biased to pivot in a direction that would move the eyelet  294  out of the travel path  290  absent tension from the looper thread  202 . 
     In response to the drop wire  292  pivoting beyond a predetermined angle indicative of a loss of tension in the looper thread  202 , the switch may change from a state indicative of sufficient tension (e.g., an open state) to a state indicative of a lack of sufficient tension (e.g., a closed state). A lack of tension on the looper thread  202  may indicate the thread has come loose from the looper  76 , broken, or run out. Thus, in response to detecting the change of state in the switch indicating the lack of sufficient tension on the looper thread  202 , operation of the machine  10  may be halted. 
     The lift arm  296  and actuator  298  may be configured so that when the sewing head  70  is operational, the lift arm  296  is normally held in a position that does not obstruct the pivoting movement of the drop wire  292 . In this condition, a loss of tension on the looper thread  202  allows the drop wire  292  to pivot out of the travel path  290  and trip the switch, as depicted by the lift arm  296  on the right in  FIGS. 8A and 8B . If a pattern is being quilted that does not require use of all the sewing heads  70  of machine  10 , the unneeded sewing heads  70  may be taken off line. In this scenario, the controller  44  may cause the actuator  298  to position the lift arm  296  on the off-line sewing heads  70  so that the lift arm  296  obstructs the pivoting movement of the drop wire  292 , as depicted by the lift arm  296  on the left in  FIGS. 8A and 8B . 
     When the lift arm  296  is positioned to obstruct the drop wire  292 , a lack of tension on the looper thread  202  will not cause the drop wire  292  to pivot out of the travel path  290  due to the presence of the lift arm  296  in the path of the drop wire  292 . The lift arm  296  may thereby be used to prevent an inadvertent shutdown of the machine  10  in the event the looper thread  202  of an inactive sewing head  70  comes loose or otherwise loses tension. The controller  44  may also cause the actuator  298  to position the lift arm  296  to obstruct the pivoting movement of the drop wire  292  before or concurrently with operation of the pull-off mechanism  266 . 
     The pull-off mechanism  266  includes an actuator  300 , a puller  302  that is coupled to the actuator  300  by a link  304 , and a stationary member  306  configured to locate the link  304  with respect to the mounting plate  268 . The stationary member  306  may include a channel through which the link  304  reciprocates along a generally linear path  308  in response to activation of the actuator  300 . Thread guides  310 ,  312  may be coupled to the stationary member  306  and configured so that when the puller  302  of pull-off mechanism  266  is in a retracted position, the looper thread guides  310 ,  312  are generally aligned with a looper thread guide  314  that is coupled to the puller  302 . 
     In response to actuation of the actuator  300  by the controller  44 , the puller  302  of pull-off mechanism  266  may move from a retracted position depicted in  FIG. 8A  to an extended position depicted in  FIG. 8B . The resulting movement of the thread guide  314  of puller  302  relative to the stationary thread guides  310 ,  312  may cause a length of looper thread  202  to be pulled from the looper thread spool  68 . To facilitate pulling this length of looper thread  202  from the looper thread spool  68 , the controller  44  may cause the thread tensioner  262  of looper thread handler  92  to release or reduce tension on the looper thread  202  prior to activation of the actuator  300 . The length of looper thread  202  pulled by the pull-off mechanism  266  when it is extended may provide a controlled amount of slack between the looper  76  and the looper thread handler  92  when the puller  302  of pull-off mechanism  266  is retracted. The controller  44  may also activate the actuator  298  of thread tension monitor  264  prior to retracting the puller  302  of pull-off mechanism  266  to prevent the resulting slack in the looper thread  202  from tripping the thread tension monitor  264  of looper thread handler  92 . 
     The position of the needle  72  may be described in terms of the angular position of the crank pulley  110 . For reference purposes, the position of the crank pulley  110  is considered to be at a 0-degree position when the needle  72  is at its most extended position through the quilting plane  50  along its axis  74 , or its Bottom Dead Center (BDC) position. When the needle  72  is at its most retracted position above the quilting plane  50  along its axis  74 , or its Top Dead Center (TDC) position, the crank pulley  110  is at 180 degrees. Because the movement of the looper  76  and retainer  90  are synchronized with the movement of the needle  72 , the angular position of the crank pulley  110  also defines the positions of these elements. Thus, the orientation of the needle  72 , looper  76 , and retainer  90 , or the “stitch forming elements”  72 ,  76 ,  90 , may be fully defined as a function of the angular position of the crank pulley  110 , with each stitch cycle beginning at the 0-degree reference position and repeating for each 360 degrees of rotation. 
       FIGS. 9A and 10A  provide a perspective and top-down views, respectively, that illustrate the positions of the stitch forming elements  72 ,  76 ,  90  at a point in the stitch cycle associated with the 0-degree position of the crank pulley  110 . In this position, the needle  72  is fully extended through the web  18  and needle hole  86  of needle plate  48 . The looper  76  is in its most rearward position (i.e., its most elongated position in the positive direction of the x-axis  54 ), and the retainer  90  is in its leftmost position as viewed from behind the looper  76  (i.e., its most elongated position in the positive direction of y-axis  56 ). The needle thread  126  passes through an eye  316  of needle  72  proximate the tip thereof, and extends from the opposite side of the needle  72  to the last formed stitch  318 . The looper thread  202  extends from the tip  194  of hook  192  to the last formed stitch  318 , which is now completely formed but may remain to be tightened. 
     As the stitch cycle moves forward from the 0-degree position, the needle  72  begins to retract by moving along its axis  74  in a positive direction with respect to the z-axis  58 , and the looper  76  begins to move forward in a negative direction with respect to the x-axis  54  as it rotates about the axis  96  of looper shaft  94 . Simultaneously, the retainer  90  begins to travel around a closed path while retaining its orientation. In the embodiment shown, the forward path of retainer  90  is a clockwise circular movement in the horizontal x-y plane such that the lobe  250  of retainer  90  generally orbits the axis  74  of needle  72 . 
     At about the 40-degree point in the stitching cycle, forward rotation of the drive pulley  110  brings the stitch forming elements  72 ,  76 ,  90  to the positions depicted in  FIGS. 9B and 10B . At this point, the tip  194  of hook  192  passes against the looper facing side of the needle  72  and slips between the needle thread  126  and the needle  72  as it enters from the stitch side of the needle  72 . Concurrently with this movement, the web  18  begins to move in the direction of the pattern as determined by a pattern control program in the controller  44 , which is depicted as a downstream or positive direction along the x-axis  54 . 
     Referring to  FIGS. 9C and 10C , as the crank pulley  110  approaches approximately the 100° point in the stitch cycle, the web  18  has moved approximately one-half stitch in relation to the needle  72 , the needle thread  126  has formed a loop around the hook  192  of looper  76 , and the looper thread  202  has been pulled forward by the tip  194  of hook  192  a sufficient distance through the loop of needle thread to enter the notch  246  of retainer  90 .  FIGS. 9D and 10D  depict stitch forming elements  72 ,  76 ,  90  approximately 180-degrees into the stitch cycle. At this point, the needle  72  reaches its most retracted position, the looper  76  reaches its most forward position, the retainer  90  reaches its most elongated position in the negative direction of y-axis  56 , and the needle thread  126  joins the looper thread  202  in the notch  246  of retainer  90 . 
     The needle  72  passes through its TDC position and begins to extend back toward the web  18  by moving along its axis  74  in a negative direction with respect to the z-axis  58 . As illustrated by  FIGS. 9E and 10E , the needle  72  begins to emerge from the needle hole  86  of needle plate  48  as the crank pulley  110  reaches about the 270-degree position in the stitch cycle. At this point, the looper  76  is moving rearward (e.g., in a positive direction with respect to x-axis  54 ), and the retainer  90  is moving in a positive direction with respect to y-axis  56 , thereby positioning the threads  126 ,  202  so that they are positively displaced along the y-axis with respect to the looper  76  and the needle  72 . The movement of the retainer  90  opens a triangle  320  having sides defined by the needle thread  126 , the hook  192  of looper  76 , and the looper thread  202 . 
     As the stitch cycle continues, the tip of needle  72  extends along axis  74  through the triangle  320 , with the stitch forming elements  72 ,  76 ,  90  reaching the positions shown in  FIGS. 9F and 10F  at about the 310-degree position of the crank pulley  110 . As can be seen, the tip  194  of hook  192  passes the needle  72  so that the needle  72  is positioned between the hook  192  of looper  76  and the retainer  90 . At approximately the 340-degree position depicted in  FIGS. 9G  and  10 G, the looper  76  has pivoted rearward sufficiently so that the needle thread  126  has slipped off the tip  194  of hook  192  and now forms a loop around the looper thread  202 . Shortly thereafter, the stitch forming elements reach the 0-degree or BDC position, from which position they can begin the next stitch cycle. 
     The stitch forming elements continue to cycle through the positions of  FIGS. 9A-9G and 10A-10G , forming one stitch with each cycle as the web  18  is moved relative to the stitch forming elements in response to signals from the controller  44  so that the quilting pattern is sewn in the web  18 . When the pattern is completed, the controller  44  may execute a tacking, cutting, and repositioning operation which tacks the needle and looper threads at the end of the completed pattern so that the threads do not unravel. 
       FIG. 11  illustrates a flow-chart depicting a process  330  that may be executed by the controller  44  to cut one or more of the needle and looper threads  126 ,  202  after the tack sequence is complete. Cutting the threads, and in particular the looper thread  202 , may allow the controller  44  to reposition the web  18  at the starting point for the next quilted pattern using higher rate of speed than is possible in machines that do not cut the looper thread  202 . In block  332 , the process  330  moves the stitch forming elements  72 ,  76 ,  90  to an initial position, e.g., by advancing the stitch forming elements  72 ,  76 ,  90  to the BDC or 0-degree position. 
     The process  330  may proceed to block  334  and position the threads  126 ,  202  in the recessed portion  254  of retainer  90 . To this end, the process  330  may move the stitch forming elements  72 ,  76 ,  90  in a reverse direction, e.g., by rotating the crank pulley  110  backwards by a predetermined amount using the drive system  24 . The predetermined amount of reverse rotation may be an amount sufficient to cause the portions the needle thread  126  and looper thread  202  between the looper  76  and the web  18  to enter the recessed portion  254  of retainer  90 , e.g., 70 degrees. At the end of this movement, the stitch forming elements  72 ,  76 ,  90  and threads  126 ,  202  may be positioned as depicted in  FIGS. 9H and 10H . 
     The process  330  may proceed to block  336  and release tension on the looper thread  202 . The process  330  may release tension on the looper thread  202  by activating the actuator  272  of thread tensioner  262 . In response, the actuator  272  may cause the friction surface of movable member  278  to move away from, or press with less force against, the friction surface of stationary member  276  so that the looper thread  202  can pass through the thread tensioner  262  without encountering significant resistance. 
     In block  338 , the process  330  pulls a predetermined amount of looper thread  202  off the looper thread spool  68 . To this end, the process  330  may extend the puller  302  of pull-off mechanism  266  by activating the actuator  300  thereof. The resulting movement of the thread guide  314  of the puller  302  relative to the thread guides  310 ,  312  of stationary member  306  pulls looper thread  202  off the looper thread spool  68 . 
     Referring now to  FIGS. 9I and 10I , and with continued reference to  FIG. 11 , in block  340 , the process  330  extends adjuster  210  of adjuster assembly  88  by activating the actuator  218 . Activating the actuator  218  urges the adjuster  210  in a negative direction along the y-axis  56  of coordinate system  52  so that the adjuster  210  is extended towards a point in the looper thread  202  between the eye  200  of looper  76  and the recessed portion  254  of retainer  90 . The catch  220  of adjuster  210  is thereby extended past the looper thread  202 . 
     In block  342 , the process  330  may release tension on the needle thread  126  and provide slack to the looper  76 . The process  330  may release tension on the needle thread  126  by activating the actuator  152  of needle thread tensioner  132 , thereby reducing the pressure between the friction surface  162  of movable member  158  and the friction surface  160  of stationary member  156 . The process  330  may also activate the actuator  298  of thread tension monitor  264  to prevent the drop wire  292  from dropping and inadvertently stopping of the machine  10 . The process  330  may further provide slack to the looper thread  202  between the looper thread spool  68  and the looper  76  by retracting the puller  302  of pull-off mechanism  266  using the actuator  300 . 
     In block  344 , the process  330  pulls the looper thread  202  off the looper  76  by activating the actuator  218  to retract the adjuster  210  of adjuster assembly  88 . As the adjuster  210  retracts, the catch  220  of adjuster  210  captures the looper thread  202  at a point between the eye  200  of looper  76  and the cutting edge  256  of retainer  90 . As the catch  220  of adjuster  210  continues to retract, the catch  220  pulls the looper thread  202  away from the looper  76  in a positive direction with respect to the y-axis. Upon full retraction, the adjuster  210  of adjuster assembly  88  may have pulled a predetermined length of looper thread  202  between the web  18  and the eye  200  of looper  76 , as shown in  FIGS. 9J and 10J . Pulling the looper thread  202  off the looper  76  may take up at least a portion of the slack between the looper thread spool  68  and the looper  76 , and places a portion of the looper thread  202  in a cutting position, e.g., in contact with or proximate to the cutting edge  256  of retainer  90 . 
     In block  346 , the process  330  positions the stitch forming elements  72 ,  76 ,  90  in the TDC or 180-degree position depicted in  FIGS. 9K and 10K . The process  330  may position the stitch forming elements  72 ,  76 ,  90  at TDC using the drive system  24  to rotate the crank pulley  110  backwards by about 110 degrees. Fully retracting the needle  72  may allow movement of the web  18  relative to the sewing head  70 . 
     In block  348 , the process  330  cuts the needle thread  126  and/or looper thread  202  by moving the web  18 . The process  330  may move the web  18 , for example, at a cutting speed in a positive direction with respect to the x-axis  54  (i.e., downstream). Because the needle and looper threads  126 ,  202  are anchored to the web  18  by the tack stitches, movement of the web  18  will pull on these threads. When the thread tensioners  132 ,  262  are applying little or no tension to their respective needle and/or looper threads  126 ,  202 , movement of the web  18  may pull thread  126 ,  202  through the eye  316  of needle  72  and/or the eye  200  of looper  76 , respectively. In contrast, when the thread tensioners  132 ,  262  are applying tension, movement of the web  18  may stretch the needle and looper threads  126 ,  202  across the cutting edge  256  of retainer  90 . In this case, movement of the web  18  may press the needle and looper threads  126 ,  202  against the cutting edge  256  of retainer  90  with sufficient force to sever the threads. The process  330  may thereby adjust the length of the thread  126 ,  202  between the last formed stitch  318  and the severed end by applying tension to the threads  126 ,  202  at different times relative to movement of the web  18 . 
     In alternative embodiments of the invention, the process  330  may execute the blocks in a different order, eliminate certain blocks, or add additional blocks. For example, the puller  302  of pull-off mechanism  266  may be retracted after the adjuster  210  rather than before, or use of the pull-off mechanism  266  eliminated altogether. Additional steps may include wait times between blocks (e.g., 100-350 ms) that allow the actuators to reach full extension or retraction, or to allow tension on one or more of the threads  126 ,  202  to stabilize before proceeding to the next block. 
     As shown in  FIGS. 9L and 10L , each of the severed threads  126 ,  202  may include a corresponding length of thread, or a tail  350 ,  352 , that extends from the last formed stitch  318 , and another tail  354 ,  356  that extends from the eye  316  of needle  72  and the eye  200  of looper  76 , respectively. As described above, waiting to activate one or more of the thread tensioners  132 ,  262  until after the web  18  has moved a distance with respect to the needle  72  may result in the tails  350 ,  352  having an increased length. Applying tension to the threads  126 ,  202  while the web  18  is advanced pulls the tensioned threads  126 ,  202  against the cutting edge  256  of retainer  90 , cutting the threads  126 ,  202  from below the needle plate  48 . The cutting may be timed to leave a sufficient length of the tails  350 ,  352  on the back side of the web  18  to prevent unraveling of the last formed stitch  318 . The adjuster  210  may be configured to produce sufficient length of the tail  356  of looper thread  202  to prevent unthreading of looper  76 . The tails  350 ,  352  of the threads  126 ,  202  on the back side of the web  18  will be inside of the bedding or furniture, and thus unseen in the finished product. In any case, after the threads have been severed, the process  330  may change the speed and/or direction of the movement of the web  18  to position the web  18  at the starting point of the next quilting pattern. 
     Advantageously, the adjuster  210  may provide an additional controlled length of looper thread  202  between the eye  200  of looper  76  and the cutting edge  256  of retainer  90  as compared to machines lacking this feature. This additional length may provide a tail  356  having consistent controlled length that trails from the eye  200  of looper  76 . The increased length of tail  356  may in turn reduce the likelihood that the looper  76  will become unthreaded. Machines lacking the adjuster  210  may forgo cutting the looper thread  202 , and merely allow the thread  202  to feed from the eye  200  of looper  76  as the web  18  is moved from one pattern to the next to prevent the looper  76  from becoming unthreaded. In this scenario, because downstream movement of the web  18  may be opposed to the direction from which the looper thread  202  is fed to the looper  76 , the looper thread  202  may be drawn through the looper  76  at twice the speed of the web  18 . This doubling of speed may further lower the upper limit on how fast the web  18  can be moved from one pattern to the next without breaking the looper thread  202 . By pulling the desired amount of looper thread  202  without movement of the web  18 , and enabling the looper thread to be cut without a significant risk of unthreading the looper  76 , the adjuster  210  may allow the machine  10  to move the web  18  at a higher speed between patterns than is possible with machines that lack this feature. 
       FIG. 12  illustrates a flow-chart depicting a process  360  that may be executed by the controller  44  to initiate quilting of a selected pattern subsequent to executing process  330 . The stitch forming elements  72 ,  76 ,  90  may initially be in the TDC or 180-degree position depicted by  FIGS. 9L and 10L  so that the web  18  can be positioned at the starting position without interference from the needles  72 . 
     In block  362 , the process  360  may determine which sewing heads  70  are to be active and which sewing heads are to be inactive for the selected pattern. The process  360  may make this determination, for example, based on a data file (e.g., a Computer Aided Design (CAD) file) that defines the positions and/or stitching paths of the individual patterns to be quilted in the web  18 . The data file may be, for example, programmed into the controller  44  by an operator and/or received by the controller  44  from an external computing system. 
     In response to determining which sewing heads  70  are to be active, the process  360  may engage the coupling device  104  of each needle assembly  60  corresponding to an active sewing head  70 , and disengage and/or verify disengagement of the coupling device  104  for each needle assembly  60  corresponding to an inactive sewing head  70 . For each sewing head  70  that is not being used to quilt the selected pattern, the process  360  may also activate the actuator  144  of thread clamp  130  for the corresponding needle assembly  60 . In response to activation of the actuator  144 , the clamping mechanism  138  may clamp the corresponding needle thread  126  of the inactive sewing head  70  between the clamping surfaces  148 ,  150  of the thread clamp  130 . The process  360  may thereby prevent the needle thread  126  from moving while the pattern is being quilted. 
     The thread clamp  130  may provide the controller  44  with independent control of the needle thread  126  in each needle assembly  60  so that the thread tensioners  132  of needle thread handlers  82  can be controlled synchronously by a single control signal. For example, the controller  44  may open/close a single valve that provides compressed air to the actuator  152  of each thread tensioner  132  to simultaneously control thread tension on the active needle assemblies  60 , and rely on the thread clamp  130  to prevent thread from being pulled from the needle thread spools  66  associated with inactive needle assemblies  60 . The process  360  may also activate the actuator  184 , thereby raising the lift arm  182  of the thread tension monitor  134  for each inactive needle assembly  60 . This may prevent the machine  10  from being inadvertently stopped due to a lack of tension on the needle thread  126  of an inactive needle assembly  60 . 
     Although the looper  76  and retainer  90  of the looper assemblies  62  are generally described as being jointly coupled to the motor  22  by the looper shafts  94  and rigid bars  260 , respectively, embodiments of the invention are not limited to this configuration. Alternative embodiments of the invention may include machines in which the loopers  76  and retainers  90  are independently coupled to the drive system  24 , or that are otherwise individually driven. In these alternative embodiments, the process  360  may also deactivate the looper assembly  62  of each deactivated sewing head  70  by activating/deactivating one or more motors or coupling devices. 
     Advantageously, deactivating unused needle assemblies  60  may reduce wear on the needle assemblies  60 , as well as energy consumption and/or noise produced by the machine  10  as compared to machines lacking this feature. Once the needle assemblies  62  of the sewing heads  70  have been coupled and/or decoupled to the drive system  24 , the process  360  may wait for a period of time (e.g., 500 ms). During this waiting period, the process  360  may verify that each needle  72  of the active sewing heads  70  is at TDC. 
     In block  364 , the process  360  may release the tail  356  of looper thread  202 . To this end, the process  360  may move the stitch forming elements  72 ,  76 ,  90  forward by a predetermined amount, e.g., by advancing the crank pulley  110  about 80 degrees to the 260-degree position. Concurrently with or following this forward movement of the stitch forming elements  72 ,  76 ,  90 , the process  360  may extend the adjuster  210 , thereby releasing the tail  356  of looper thread  202 . The tail  356  may relax into a position that extends the tail  356  from the eye  200  of looper  76  generally upstream of the needle hole  86  of needle plate  48 , as depicted in  FIGS. 9M and 10M . 
     For embodiments of the invention including the air nozzle  185 , the process  360  may also blow air  187  out of the nozzle  185  to help free the tail  356  of looper thread  202  from the catch  220  and/or position the tail  356  to be picked up by the needle thread  126  when stitching resumes. In any case, the process  360  may wait for a period of time (e.g., 250 ms) after extension of the adjuster  210  to allow the tail  356  to reach its relaxed state. In yet another embodiment of the invention, the process  360  may skip block  364 , thereby allowing the adjuster  210  to maintain control over the tail  356 . In this alternative embodiment, the holder assembly  88  may be configured so that the looper thread  202  is positioned with respect to the needle  72  in a manner that increases the likelihood of the looper thread  202  being picked up by the needle thread  126  when stitching resumes. 
     In block  366 , the process  360  may position the stitch forming elements  72 ,  76 ,  90  at the 0-degree or BDC position. This repositioning of the stitch forming elements  72 ,  76 ,  90  may be implemented by moving the stitch forming elements  72 ,  76 ,  90  forward by a predetermined amount, e.g., about 100 degrees. As the elements are advanced, the needle  72  may advance through the web  18 , thereby pulling the tail  354  of needle thread  126  at least partially through the web  18 . At the same time, the looper  72  may move rearward, pulling the tail  356  of looper thread  202  clear of the catch  220  of adjuster  210 . Once the stitch forming elements have reached BDC, the process  360  may retract the adjuster  210 , leaving the stitch forming elements  72 ,  76 ,  90  positioned as depicted in  185 . In an alternative embodiment of the invention, the flow of air  187  from the air nozzle  185  may be provided continuously or intermittently until the adjuster  210  is retracted to ensure that the tail  356  of looper thread  202  is released by, and remains free of, the catch  220 . To this end, the flow of air provided by the air nozzle  185  through the bore connecting the opening  198  and eye  200  of looper  76 , as well as around the looper  76 , may urge the tail  364  of looper thread  200  into a position that keeps the tail  364  clear of the catch  220  when it is retracted. 
     In block  368 , the process  360  may perform a tail wipe procedure so that the tail  354  of needle thread  126  is left on the underside of web  18  at the beginning of the quilting pattern. As shown in  FIG. 9N , the tail  354  of needle thread may initially extend from the eye  316  of needle  72  through the web  18  so that a portion of the tail  354  protrudes from the front side of the web  18 . To initiate the tail wipe procedure, the process  360  may advance the stitch forming elements  72 ,  76 ,  90  by a predetermined amount (e.g., 180 degrees) to the TDC position depicted in  FIGS. 9P and 10P . As the stitch forming elements  72 ,  76 ,  90  are advanced, the hook  196  of looper  76  may pass between the needle thread  126  and the needle  72  as previously described with respect to  FIGS. 9B-9D . In the TDC position, the needle thread  126  may form a loop around the hook  196  of looper  76 , and the tail  354  of needle thread  126  may extend from the looper  76  to the front side of the web  18 . 
     While the stitch forming elements  72 ,  76 ,  90  are in the TDC position, the process  360  may increase the resistance provided by the thread clamp  130  and/or thread tensioner  132 . The process  360  may then move the web  18  a distance sufficient to pull the tail  354  of needle thread  126  completely through the web  18  as shown in  FIGS. 9Q and 10Q . The process  360  may then return the web  18  to its previous position, in response to which the tail  354  of needle thread  126  may drop through the needle hole  86  of needle plate  48 . The process  360  may then set the needle and looper thread tensioners  132 ,  262  to sewing levels, lock the coupling devices, and resume sewing. 
     Referring now to  FIG. 13 , the controller  44  may include a processor  400 , a memory  402 , an input/output (I/O) interface  404 , and a Human Machine Interface (HMI)  406 . The processor  400  may include one or more devices configured to manipulate signals (analog or digital) based on operational instructions that are stored in memory  402 . Memory  402  may include a single memory device or a plurality of memory devices including, but not limited to, read-only memory (ROM), random access memory (RAM), volatile memory, non-volatile memory, hard drives, optical storage, mass storage devices, or any other device capable of storing data. 
     The processor  400  may operate under the control of an operating system  408  that resides in memory  402 . The operating system  408  may manage controller resources so that computer program code embodied as one or more computer software applications, such as a controller application  410  residing in memory  402 , can have instructions executed by the processor  400 . One or more data structures  412  may also reside in memory  402 , and may be used by the processor  400 , operating system  408 , and/or controller application  410  to store data. 
     The I/O interface  404  operatively couples the processor  400  to the other components of the machine  10 , and may also couple the processor  400  to an external computing system or network (not shown). The external computing system or network may be used, for example, to exchange data files, such as quilting patterns, updated applications, and/or other operational data, with controller  44  to update the controller  44  and/or collect data related to the operation of the quilting machine  10 . 
     The I/O interface  404  may include signal processing circuits that condition or encode/decode incoming and outgoing signals so that the signals are compatible with both the processor  400  and the components to which the processor  400  is coupled. To this end, the I/O interface  404  may include analog to digital (A/D) and/or digital to analog (D/A) converters, voltage level and/or frequency shifting circuits, optical isolation and/or driver circuits, protocol stacks, solenoids, relays, pneumatic valves, and/or any other devices suitable for coupling the processor  400  to the other components of the machine  10  and/or an external computing system. 
     The HMI  406  may be operatively coupled to the processor  400  of controller  44  to enable a user to interact directly with the controller  44 . The HMI  406  may include video or alphanumeric displays, a touch screen, a speaker, and any other suitable audio and visual indicators capable of providing data to the user. The HMI  406  may also include input devices and controls such as an alphanumeric keyboard, a pointing device, keypads, pushbuttons, control knobs, microphones, etc., capable of accepting commands or input from the user and transmitting the entered input to the processor  400 . 
     In general, the routines executed to implement the embodiments of the invention, whether implemented as part of an operating system or a specific application, component, program, object, module or sequence of instructions, or a subset thereof, may be referred to herein as “computer program code,” or simply “program code.” Program code typically comprises computer-readable instructions that are resident at various times in various memory and storage devices in a computer and that, when read and executed by one or more processors in a computer, cause that computer to perform the operations necessary to execute operations and/or elements embodying the various aspects of the embodiments of the invention. Computer-readable program instructions for carrying out operations of the embodiments of the invention may be, for example, assembly language or either source code or object code written in any combination of one or more programming languages. 
     Various program code described herein may be identified based upon the application within which it is implemented in specific embodiments of the invention. However, it should be appreciated that any particular program nomenclature which follows is used merely for convenience, and thus the invention should not be limited to use solely in any specific application identified and/or implied by such nomenclature. Furthermore, given the generally endless number of manners in which computer programs may be organized into routines, procedures, methods, modules, objects, and the like, as well as the various manners in which program functionality may be allocated among various software layers that are resident within a typical computer (e.g., operating systems, libraries, API&#39;s, applications, applets, etc.), it should be appreciated that the embodiments of the invention are not limited to the specific organization and allocation of program functionality described herein. 
     The program code embodied in any of the applications/modules described herein is capable of being individually or collectively distributed as a program product in a variety of different forms. In particular, the program code may be distributed using a computer-readable storage medium having computer-readable program instructions thereon for causing a processor to carry out aspects of the embodiments of the invention. 
     Computer-readable storage media, which is inherently non-transitory, may include volatile and non-volatile, and removable and non-removable tangible media implemented in any method or technology for storage of data, such as computer-readable instructions, data structures, program modules, or other data. Computer-readable storage media may further include RAM, ROM, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other solid state memory technology, portable compact disc read-only memory (CD-ROM), or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired data and which can be read by a computer. A computer-readable storage medium should not be construed as transitory signals per se (e.g., radio waves or other propagating electromagnetic waves, electromagnetic waves propagating through a transmission media such as a waveguide, or electrical signals transmitted through a wire). Computer-readable program instructions may be downloaded to a computer, another type of programmable data processing apparatus, or another device from a computer-readable storage medium or to an external computer or external storage device via a network. 
     Computer-readable program instructions stored in a computer-readable medium may be used to direct a computer, other types of programmable data processing apparatuses, or other devices to function in a particular manner, such that the instructions stored in the computer-readable medium produce an article of manufacture including instructions that implement the functions, acts, and/or operations specified in the flow-charts, sequence diagrams, and/or block diagrams. The computer program instructions may be provided to one or more processors of a general purpose computer, a special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the one or more processors, cause a series of computations to be performed to implement the functions, acts, and/or operations specified in the flow-charts, sequence diagrams, and/or block diagrams. 
     In certain alternative embodiments, the functions, acts, and/or operations specified in the flow-charts, sequence diagrams, and/or block diagrams may be re-ordered, processed serially, and/or processed concurrently consistent with embodiments of the invention. Moreover, any of the flow-charts, sequence diagrams, and/or block diagrams may include more or fewer blocks than those illustrated consistent with embodiments of the invention. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the embodiments of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, actions, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, actions, steps, operations, elements, components, and/or groups thereof. Furthermore, to the extent that the terms “includes”, “having”, “has”, “with”, “comprised of”, or variants thereof are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term “comprising”. 
     While all the invention has been illustrated by a description of various embodiments and while these embodiments have been described in considerable detail, it is not the intention of the Applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and method, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the Applicant&#39;s general inventive concept.