SEWING HEAD

CROSS REFERENCE TO RELATED APPLICATIONS

[0001]This application claims the benefit of U.S. Provisional Application No. 63/715,159 filed on Nov. 1, 2024 and U.S. Provisional Application No. 63/805,068 filed on May 13, 2025 the entire contents each of which are incorporated herein by reference thereto.

TECHNICAL FIELD

[0002]Exemplary embodiments of the present disclosure pertains to the art of sewing heads and/or robotic sewing heads for use in sewing processes.

BACKGROUND

[0003]Sewing production may involve a robotic sewing cell. Robotic sewing technology may use a sewing head. As the types of materials being sewn together changes improvements are needed to existing sewing heads in order to perform the desired stitching process.

[0004]Composite materials may be sewn together prior to the sewn composite material being resin infused to create a final, cured composite part. The composite materials are flexible prior to the curing step. Thus, it is desirable to provide support to the composite materials during the stitching process which occurs prior to the curing process.

[0005]As such, it is desirable to provide an improved robotic sewing head.

BRIEF DESCRIPTION

[0006]Disclosed is a composite sewing head.

[0007]Also disclosed is a composite sewing head with a needle and sleeve.

[0008]Disclosed is a composite sewing head, including; a feed needle bar configured to drive a feed needle; and a catcher needle bar configured to drive a catcher needle, wherein the feed needle bar and the catcher needle bar are configured to have linear and rotary motion when a stitch is created by the composite sewing head.

[0009]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the composite sewing head further includes a catcher needle bar drive assembly and a feed needle bar drive assembly, wherein the catcher needle bar drive assembly and the feed needle bar drive assembly are located on one side of an article being stitched by the composite sewing head.

[0010]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the linear motion of the catcher needle bar and the feed needle bar is accomplished by motion of a crank arm connected to a crankshaft counterweight, the crankshaft counterweight is rotated by a needle bar drive shaft and the needle bar drive shaft is rotated by a drive motor through a series of pulleys and belts.

[0011]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the rotary motion of the catcher needle bar and the feed needle bar is relative to an article being stitched is accomplished via rotation of a needle bar rock frame and rotation of the needle bar rock frame is accomplished via rotation of a rock frame drive shaft and rotation of the rock frame drive shaft is accomplished via linkage connected to an eccentric mounted to a needle bar drive shaft.

[0012]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the feed needle bar and the catcher needle bar are each driven by a separate needle bar drive shaft that is rotated via either a single motor that rotates the needle bar drive shaft of the feed needle bar and the needle bar drive shaft of the catcher needle bar or dual motors are used to simultaneously rotate the needle bar drive shaft of the feed needle bar and the needle bar drive shaft of the catcher needle bar.

[0013]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the single motor is coupled to a second pulley on one of the needle bar drive shaft of the feed needle bar and the needle bar drive shaft of the catcher needle bar.

[0014]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the composite sewing head further includes a pair of pulleys, one of the pair of pulleys being mounted on the needle bar drive shaft of the feed needle bar and the other one of the pair of pulleys is mounted on the needle bar drive shaft of the catcher needle bar, and the pair of pulley are connected with a single belt.

[0015]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, timing between the feed needle bar and the catcher needle bar is accomplished via mechanical adjustment.

[0016]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, each motor of the dual motors is directly coupled to a single upper needle bar drive shaft.

[0017]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, a timing of the dual motors is accomplished mechanically, electrically, or a combination thereof.

[0018]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the composite sewing head further includes a catcher needle sleeve slidably received upon the catcher needle, the catcher needle sleeve being configured to cover an opening of a hook of the catcher needle during travel of the catcher needle upward through an article being sewn by the catcher needle sleeve.

[0019]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the composite sewing head further includes a camera utilized for detection and documentation of defects in a completed stitch of the composite sewing head.

[0020]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, an angle between the feed needle and the catcher needle can be manually adjusted between 35 and 50 degrees.

[0021]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, an angle between the feed needle and the catcher needle perpendicular to a needle plane can be adjusted to increase a distance between two stitch paths created on a top surface an article being sewn by the composite sewing head.

[0022]Disclosed is a composite sewing head, including: a needle bar transport for a thread feed needle and a thread catcher needle that is arranged to be parallel to a needle plane of the thread feed needle and a thread catcher needle, with the needle plane parallel or nearly parallel to a stitch path.

[0023]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, an angle between the catcher needle and the feed needle is adjustable.

[0024]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the catcher needle further comprises a sleeve to prevent a hook of the catcher needle from engaging with laminate fibers upon retraction the catcher needle from a laminate containing the laminate fibers.

[0025]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the catcher needle further comprises a sleeve to prevent a hook of the catcher needle from engaging with laminate fibers upon retraction the catcher needle from a laminate containing the laminate fibers.

[0026]Also disclosed is a sewing assembly, including: a composite sewing head, the composite sewing head including: a needle bar transport for a thread feed needle and a thread catcher needle that is arranged to be parallel to a needle plane of the thread feed needle and a thread catcher needle, with the needle plane parallel or nearly parallel to a stitch path; a fixture for supporting a composite to be sewn by the composite sewing head, the fixture having a channel located in a surface of the fixture, the channel having a width configured to accept movement of the thread feed needle and a thread catcher needle as the pass through the composite; and a robot secured to the composite sewing head for manipulating a location of the composite sewing head with respect to the fixture as the composite is being sewn by the composite sewing head.

[0027]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, an angle between the catcher needle and the feed needle is adjustable.

[0028]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the catcher needle further comprises a sleeve to prevent a hook of the catcher needle from engaging with laminate fibers of the composite upon retraction the catcher needle from composite containing the laminate fibers.

[0029]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the catcher needle further comprises a sleeve to prevent a hook of the catcher needle from engaging with laminate fibers of the composite upon retraction the catcher needle from composite containing the laminate fibers.

[0030]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the sewing assembly further includes a sensor for detecting a thickness of the composite.

[0031]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the sensor is located at a defined distance ahead of but preferably inline with the needle plane.

[0032]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the sensor is an ultrasonic sensor.

[0033]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the sensor provides feedback to a sewing head controller for controlling a location of the composite sewing head with respect to the composite.

[0034]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, an angle between the catcher needle and the feed needle is adjustable.

[0035]Also disclosed is a method for sewing a composite material, including: sewing the composite material with a composite sewing head, wherein a needle bar transport for a thread feed needle and a thread catcher needle of the composite sewing head that is arranged to be parallel to a needle plane of the thread feed needle and a thread catcher needle, with the needle plane parallel or nearly parallel with a stitch path.

[0036]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the composite sewing head is secured to a robot for manipulating a location of the composite sewing head with respect to a fixture for supporting a composite to be sewn by the composite sewing head, the fixture having a channel located in a surface of the fixture, the channel having a width configured accept movement of the thread feed needle and a thread catcher needle as they pass through the composite.

[0037]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, an angle between the catcher needle and the feed needle is adjustable.

[0038]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the catcher needle further comprises a sleeve to prevent a hook of the catcher needle from engaging with laminate fibers of the composite upon retraction the catcher needle from composite containing the laminate fibers.

[0039]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the method includes detecting a thickness of the composite with a sensor operably coupled to a sewing head controller for controlling a location of the composite sewing head with respect to the composite.

[0040]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the sensor is located at a defined distance ahead of and inline with the needle plane.

[0041]In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the sensor is an ultrasonic sensor.

BRIEF DESCRIPTION OF THE DRAWINGS

[0042]The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:

[0043]FIG. 1 illustrates a conventional machine feed;

[0044]FIG. 2 illustrates a sideslip machine feed;

[0045]FIG. 3 illustrates a machine feed and sewing head in accordance with the present disclosure;

[0046]FIG. 3A illustrates a machine feed and sewing head in accordance with the present disclosure;

[0047]FIG. 4 is perspective view of a portion of a composite sewing head in accordance with the present disclosure;

[0048]FIG. 5 is a view of a catcher needle and sleeve in accordance with the present disclosure;

[0049]FIG. 6 is a view of a catcher needle in accordance with the present disclosure;

[0050]FIG. 7 is a view of a sleeve for a catcher needle in accordance with the present disclosure;

[0051]FIG. 8 is a view of a sewing cell in accordance with the present disclosure;

[0052]FIG. 9 is a top view of a sewing fixture in accordance with the present disclosure;

[0053]FIG. 10A is a view of a composite sewing head sewing composite laminates together on an A-side or show side of a product with a single stitch path/pass;

[0054]FIG. 10B is a view of a composite sewing head sewing composite laminates together on an A-side or show side of a product with a dual stitch path/pass;

[0055]FIG. 11A is a view of a composite sewing head sewing composite laminates together on an B-side or non-show side of a product with a single stitch path/pass;

[0056]FIG. 11B is a view of a composite sewing head sewing composite laminates together on an B-side or non-show side of a product with a dual stitch path/pass;

[0057]FIGS. 12A-12G illustrate a laminate constriction process in accordance with the present disclosure;

[0058]FIG. 13 is a view of a composite sewing head sewing composite laminates together on an A-side or show side of a product with a sewing fixture in accordance with the present disclosure;

[0059]FIGS. 14A-14D illustrate a laminate constriction process in accordance with the present disclosure;

[0060]FIG. 15A illustrates a laminate construction with no reinforcement;

[0061]FIGS. 15B-15D illustrate laminate constriction processes in accordance with alternative embodiments of the present disclosure;

[0062]FIG. 16 is an end view of a composite head design in accordance with the present disclosure;

[0063]FIG. 17 is a side view of a composite head design illustrated in at least FIG. 16 in accordance with the present disclosure;

[0064]FIG. 18 is an end view of a composite head design in accordance with the present disclosure;

[0065]FIG. 19 is a side view of a composite head design illustrated in at least FIG. 18 in accordance with the present disclosure;

[0066]FIG. 20 is an end view of a composite head design in accordance with the present disclosure;

[0067]FIG. 21 is an end view of a composite head design in accordance with the present disclosure;

[0068]FIG. 22 is a side view of a composite head design illustrated in at least FIG. 19 in accordance with the present disclosure;

[0069]FIG. 23A is view of a portion of a catcher needle in accordance with the present disclosure;

[0070]FIG. 23B is view of a portion of a sleeve for use with the catcher needle illustrated in at least FIG. 23A in accordance with the present disclosure;

[0071]FIG. 23C is view of a portion of a catcher needle and sleeve assembly in accordance with the present disclosure;

[0072]FIG. 23D is a side view of a catcher needle and sleeve assembly in accordance with the present disclosure;

[0073]FIG. 23E is a front view of a catcher needle and sleeve assembly in accordance with the present disclosure;

[0074]FIG. 23F is a top view of a catcher needle in accordance with the present disclosure;

[0075]FIG. 23G is a top view of a sleeve for use with the catcher needle illustrated in at least FIG. 23A in accordance with the present disclosure;

[0076]FIG. 23H is a top view of a catcher needle and sleeve assembly in accordance with the present disclosure;

[0077]FIG. 24 illustrates a catcher needle and sleeve interaction of a catcher needle assembly during a stitch cycle;

[0078]FIG. 25A illustrates feed and catcher needles parallel in the XZ plane with reference to the attached FIGS. ;

[0079]FIG. 25B illustrates the thread appearance on a top surface of a stitched material when the feed and catcher needles are parallel in the XZ plane and thread from the feed needle overlays loop from the catcher needle;

[0080]FIG. 26A illustrates the feed needle rotated about the point of intersection of the feed needle with the catcher needle by 10 degrees in the XZ plane with reference to the attached FIGS. ; and

[0081]FIG. 26B illustrates the thread appearance on a top surface of a stitched material when the feed needle is rotated about the point of needle intersection with the catcher needle by 10 degrees in the XZ plane with reference to the attached FIGS. and the thread from the feed needle is offset from the catcher needle loop.

DETAILED DESCRIPTION

[0082]A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.

Overview

[0083]The present disclosure is directed to a single-sided sewing head for the purpose of stitching together layers of a dry non-crimped carbon fiber multiaxial laminate composite to enhance z-axis (through thickness) strength as well as enhance the resistance to delamination of composite laminates. The non-crimped carbon fiber laminate composite can be completely dry or contain some amount of binder resin or veil which permits the composite laminate to be preformed to shape prior to stitching.

[0084]The sewing head is also used to stitch together layers of Automated Fiber Placement (AFP) and automated tape placement (ATP) composite constructions prior to resin infusion with the purpose of enhancing z-axis strength and increasing resistance to delamination.

[0085]The sewing head is also used to attach stringers, frame stacks, stringer and frame straps, tapes and other reinforcements to the skin of a composite structure.

[0086]The sewing head can be mounted to a robot to enable the head to be articulated over the surface of a 3D composite structure.

Current State-of-the-Art

[0087]A single sided sewing head using two needles and a single thread.

[0088]The thread is fed through composite laminate using a needle angled 45 degrees (feed needle) to the composite laminate surface.

[0089]While the thread feed needle is fully extended through the composite laminate, the thread from the feed needle is hooked by a second needle (catcher needle) that penetrates the composite laminate 90 degrees to the A-surface or show surface of the composite laminate.

[0090]The catcher needle then carries the thread through the composite laminate. Once pulled completely through, a thread picker engages and retains the thread, allowing the catcher needle to move downward through the loop for the next cycle before releasing the thread loop.

[0091]Referring now to FIG. 1 movement of a sewing head 10 in the direction of arrow 12 is illustrated. In FIG. 1, the movement of the sewing head 10 in the direction of arrow 12 is illustrated by the three images of the sewing head 10. The direction of arrow 12 may be referred to as the sewing head path. Here the needle plane of sewing head 10 is illustrated by the dashed lines 14. In this configuration, the needle plane 14 is arranged at a 90 degree angle with respect to the sewing head path 12 or stitch direction illustrated by arrow 16. The sewing head 10 has a thread feed needle and a thread catcher needle contained within the needle plane that is arranged 90 degrees with respect to the stitch path. Movement of the needle plane containing the thread feed needle and the thread catcher needle is facilitated by a needle bar transport 18 arranged to move the needle plane parallel to the stitch path.

[0092]The configuration of the thread feed needle and the thread catcher needle require a channel 20 defined by dashed lines 22 and 24. The passage or channel 20 is located in a fixture that supports a composite laminate that is being stitched by the sewing head 10. The channel 20 needs to be wide enough to provide clearance for the sewing needle(s) (the thread feed needle and the thread catcher needle) upon penetration through the backside of the composite laminate. The large width of the channel that is cut into the fixture along the sewing path can allow the laminate material to be pushed into the channel during sewing, which is undesirable. Current methods used to prevent material displacement into the fixture channel 20 consist of adding a veil of material between the B-side of the composite laminate and the top side of the sewing fixture to provide support to the laminate. The time required to install the veil between each part sewing cycle is excessive and leads to a significant increase in the overall processing time to produce a finished composite product. As such, the width of the channel 20 illustrated in FIG. 1 is too wide.

[0093]Referring now to FIG. 2, a sewing head 10 of a sideslip machine is illustrated. Again movement of the sewing head 10 in the direction of the sewing head path 12 is illustrated. In FIG. 2, the movement of the sewing head 10 in the direction of arrow 12 is illustrated by the three images of the sewing head 10. The direction of arrow 12 may be referred to as the sewing head path. Here the needle plane of sewing head 10 illustrated by the dashed lines 14 is offset from the sewing head path 12 or stitch direction illustrated by arrow 16 by about 5 degrees. However and in this configuration, the needle bar transport 18is arranged approximately 85 degrees with respect to the stitch path 16. See dashed lines 15.

[0094]The sewing head 10 illustrated in FIG. 2 has a thread feed needle and a thread catcher needle that are arranged about 85 degrees with respect to the stitch path. Movement of the thread feed needle and the thread catcher needle are facilitated by a needle bar transport 18 approximately 85 degrees with respect to the stitch path 16.

[0095]The configuration of the thread feed needle and the thread catcher needle of the head 10 of FIG. 2 requires a channel 20 defined by dashed lines 22 and 24. While this channel 20 is smaller than the channel 20 of FIG. 1, the robot must move the sewing head in a zig zag pattern as illustrated by line 11 in FIG. 2 to ensure that the robot path movement is parallel to the needle plane transport direction. As such, the sew path programming is complex and the sewing speed is slow as compared to what is desired.

Limitations With Current State-of-the-Art (FIGS. 1 and 2 )

[0096]There is a lack of power to drive the sewing needle(s), thread feed needle and the thread catcher needle through the composite.

[0097]Breakage of sewing needles.

[0098]The catcher needle hook tends to catch on the composite laminate as it is being withdrawn from the laminate. Damage to the composite laminate fibers can lead to reduced performance under load as well as stitching irregularities.

[0099]The thread picker can fray the thread during removal from the catcher needle.

[0100]It is also difficult to achieve consistent thread tension across stitching path.

[0101]As mentioned above, the passage or channel 20 required along the sewing path 16 in a fixture that supports the composite laminate needs to be wide enough to provide clearance for the sewing needle(s) (the thread feed needle and the thread catcher needle) upon penetration through the backside of the composite laminate. The large width of the channel that is cut into the fixture along the sewing path can allow the laminate material to be pushed into the channel during sewing.

[0102]Current methods used to prevent material displacement into the fixture channel consist of adding a veil of material between the B-side of the composite laminate and the top side of the sewing fixture to provide support to the laminate. The time required to install the veil between each part sewing cycle is excessive and leads to a significant increase in the overall processing time to produce a finished composite product.

Improvements to Current State-of-the-Art

[0103]Referring now to at least FIGS. 3, 3A, a sewing head or composite sewing head and method of the present disclosure is illustrated. Here the needle bar transport is parallel to the needle plane instead of perpendicular (e.g., 90 degrees) to the needle plane as illustrated in FIGS. 1 and 2. With the needle bar transport arranged parallel to the needle plane, and the needle plane parallel or nearly parallel (5 to 15 degrees) to the stitch path, the width of the of needle projection through the B-side of the laminate stack is reduced and thus the width of the channel 20 on the laminate support fixture can be reduced. As such the width of the channel 20 that needs to be machined into a top side surface of the laminate support fixture is minimized. This will also enable increased sewing speed.

[0104]As used herein “needle bar transport” refers to a mechanism in the sewing head 10 for facilitating reciprocal movement of at least the thread feed needle and the thread catcher needle in order to stitch a thread through a part surface.

[0105]In addition and in another embodiment of the present disclosure, the catcher needle is encapsulated by a sleeve during penetration through the composite laminate. The sleeve will cover the hook portion of the catcher needle during needle passage through the laminate and prevent the hook from engaging with the laminate fibers upon needle retraction. The sleeve is movably secured to the catcher needle to allow for a thread picker to engage and retain the thread during operation but cover the hook portion of the catcher needle during needle passage through the laminate and prevent the hook from engaging with the laminate fibers upon needle retraction.

[0106]The angle between the catcher and feed needles is adjustable so that the sewing head 10 can be setup to manage a variety of composite material thicknesses and compositions.

[0107]The sewing head 10 can also provide real time compensation for variations in the material thickness during sewing. This is provided by an ultrasonic sensor or other types of sensors or sensor means for detecting composite laminate thickness and will be placed at a defined distance ahead of the needle bar plane. This sensor will detect variation in laminate thickness and provide feedback to the sewing head controller in real time. Prior to the sewing head reaching the point of thickness variation, the position of the pressor foot position and sewing head normal to the laminate surface will be adjusted automatically to ensure a consistent depth of needle penetration along the entire stitch path. Maintaining a consistent depth of needle penetration beneath the B-side of the laminate will ensure that no stitching irregularity occurs.

[0108]Referring now to FIG. 4, portions of the sewing head 10 is illustrated. Also, illustrated is the needle plane 14. Also illustrated is a thread feed needle 28, a thread catcher needle 30, a thread picker 32, an existing stitch path 34, an existing needle bar transport direction 42, a presser foot 38, an angle 40 between the thread feed needle 28 and the thread catcher needle 30, a proposed needle bar transport direction illustrated by arrow 44, a proposed stitch path illustrated by arrow 45.

[0109]Referring now to at least FIGS. 5-7, a catcher needle 30 and a sleeve 46 for the catcher needle 30 is illustrated. FIG. 5 illustrates the catcher needle 30 and sleeve 46 while FIG. 6 illustrates the catcher needle 30 and FIG. 7 illustrated the needle sleeve 46. In one non-limiting embodiment, one non-limiting outer diameter of the catcher needle 30 is approximately 2.38 mm and one corresponding non-limiting outer diameter of the needle sleeve 46 is approximately 2.9 mm. It is, of course, understood that in accordance with the present disclosure the outer diameter of the catcher needle 30 and the outer diameter of the needle sleeve 46 may be greater or less than the aforementioned dimensions of 2.38 mm and 2.9 mm.

[0110]Referring now to at least FIG. 8, a sewing assembly 100 is illustrated in accordance with the present disclosure. The sewing assembly 100 includes the sewing head 10 which is secured to a robot 50. The stitch path 45 is normal to the plane of FIG. 8. The needle bar transport 18 is illustrated schematically by box 18 and the thread feed needle 28 and the thread catcher needle 30 are illustrated by the box labeled 28, 30. Also shown is a fixture 52 with the aforementioned channel 20. A composite laminate or laminates 54 for being sewn together are also shown. Also shown is a sensor 56 that may be secured to the sewing head 10 for detecting a thickness of the composite laminate 54 that is places at a defined distance ahead and inline with the needle bar plane. This sensor 56 will detect variations in the laminate 54 thickness and provide feedback to a sewing head controller 58 in real time. As such, and prior to the sewing head 10 reaching the point of thickness variation, both the position of the pressor foot 38 normal to the laminate 54 surface and the sewing head 10 will be adjusted automatically to ensure a consistent depth of needle penetration along the entire stitch path. Maintaining a consistent depth of needle penetration beneath the B-side of the laminate will ensure that no stitching irregularity occurs.

[0111]In an embodiment, the controller 58 may include memory to store instructions that are executed by one or more processors. The executable instructions may be stored or organized in any manner and at any level of abstraction, such as in connection with a controlling and/or monitoring operation of the robot 50 and the sewing head 10. The one or more processors can be any type of central processing unit (CPU), including a general purpose processor, a digital signal processor (DSP), a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or the like. Also, in embodiments, the memory may include random access memory (RAM), read only memory (ROM), or other electronic, optical, magnetic, or any other computer readable medium onto which is stored data and control algorithms in a non-transitory form.

[0112]FIG. 9 is a top plan view of a fixture 52 with a channel 20.

[0113]Referring now to at least FIGS. 10A, 10B, 11A and 11B, the sewing head 10 can be setup to provide a single stitch path or multiple stitch paths. FIGS. 10A, 10B, 11A and 11B illustrate a portion of composite laminates 54 being sewn together to provide a composite sewn part 102 for use in a subsequent curing process. Note, only a portion of the composite sewn part 102 is illustrated in the attached FIGS.

[0114]FIG. 10A is a view of the composite sewing head 10 sewing composite laminates together to provide the composite sewn part 102 on an A-side or show side 104 of composite sewn part 102 with a single stitch path/pass. FIG. 10B is a view of the composite sewing head 10 sewing composite laminates together to provide the composite sewn part 102 on the A-side or show side 104 of composite sewn part 102 with a dual stitch path/pass.

[0115]FIG. 11A is a view of a composite sewing head sewing 10 sewing composite laminates together to provide the composite sewn part 102 on a B-side or non-show side 106 of the composite sewn part 102 with a single stitch path/pass. FIG. 11B is a view of the composite sewing head 10 sewing composite laminates together on the B-side or non-show side 106 of the composite sewn part 102 with a dual stitch path/pass. A feed direction of the sewing of the composite sewn part 102 is illustrated by circle 108 which extends outwardly and into the FIGS. 10A-11B. The applied stitches of the composite sewing head 10 are shown by the dashed arrows/lines 110.

[0116]Utilization of two needle sets or dual stitching allows a stitch to be placed on both sides of a stringer 112 of the composite sewn part 102 at the same time instead of sequentially, which offers cycle time savings. This technique is applicable when stitching from either the A-side or B-side of the composite sewn part 102. Stitching from the B-side of the composite sewn part 102 also eliminates the need for a pocket in the tooling to accommodate the stringer webs (FIG. 13) and thus simplifies the tooling build as well as improves support for the stringer during stitching.

[0117]Referring now to at least FIGS. 12A-12G a laminate construction process in accordance with the present disclosure is illustrated. The composite sewn part 102 includes a first composite laminate or skin laminate 114 which provides the A-side or a show surface 116 and the B-side or non-show surface 118 of the composite sewn part 102, and a plurality of stringers 112, only one of which is shown, that is secured to the B-side or non-show surface 118 of the first composite laminate 114. At least FIGS. 12A-12G illustrate the securement of stringer 112 to the first composite laminate or skin laminate 114. Each one of the plurality of stringers 112 includes a first stringer portion 120 and a second stringer portion 122, which are sewn together to provide the stringer 112. Each first stringer portion 120 and each second stringer portion 122 have a flange portion 124 that is sewn to the first composite laminate 114 on the B-side or non-show surface 118 of the first composite laminate 114 of the composite sewn part 102. In addition, each first stringer portion 120 and each second stringer portion 122 have a vertical portion or web 126 that extends upwardly from the flange portion 124. The vertical portion or web 126 is integrally formed with the flange portion 124 such that stringer the first and second stringer portions 120 and 122 are formed as a single unitary structure.

[0118]The first composite laminate or skin laminate 114 and the first stringer portion 120 and the second stringer portion 122 are in one non-limiting embodiment formed from Non-Crimp Fabrics (NCF) which consist of or comprise or include unidirectional laminate plies (carbon fiber) which are kept together by stitching yarns arranged in a number of different orientations relative to the fabric production direction. The stitching yarn holds the plies together for handling but contribute little to the mechanical performance of the overall laminate construction.

[0119]Once the first composite laminate or skin laminate 114 and the first stringer portion 120 and the second stringer portion 122 are stitched together, they are resin infused to create the final, cured composite. The first composite laminate or skin laminate 114 and the first stringer portion 120 and the second stringer portion 122 may also be automated tape placement (ATP) and automated fabric placement (AFP) composites.

Improvements to Current State-of-the-Art (Process/Composite Laminate Construction)

[0120]Stabilization of the stringer 112 during fixturing and subsequent stitching to the skin layer or first composite laminate or skin laminate 114 of the composite sewn part 102 is improved via the use of a polymer reinforcement 128 (see at least FIGS. 12C-12G). It being understood that the materials and composition and layers of the first stringer portion 120 and the second stringer portion 122 are the same as the skin layer or first composite laminate or skin laminate 114. Alternatively, the materials and composition and layers of the first stringer portion 120 and the second stringer portion 122 are different from the skin layer or first composite laminate or skin laminate 114. The stringer 112 including the first stringer portion 120, the second stringer portion 122 and the skin layer or first composite laminate or skin laminate 114 can consist of, but is not limited to, multiple layers of non-crimped carbon fiber multiaxial laminate. The polymer reinforcement 128 can consist of, but is not limited to, a thermoplastic profile extrusion. In other words, the polymer reinforcement 128 is formed by an extrusion process. The polymer reinforcement 128 includes a horizontal portion 132 and an upwardly extending vertical portion 134 that extends from a portion or central portion of the horizontal portion 132 such that the polymer reinforcement 128 has a “T” shape or inverted “T” shape depending on the part orientation.

[0121]After a stringer laminate 130 (illustrated in FIG. 12A) is separated in half into the first stringer portion 120 and the second stringer portion 122 (FIG. 12B), each half or the first stringer portion 120 and the second stringer portion 122 containing an equal amount of laminate layers.

[0122]In FIG. 12C, the reinforcement 128 is placed between the two halves (the first stringer portion 120 and the second stringer portion 122) of the stringer 112 (FIG. 12D) and the stringer halves (the first stringer portion 120 and the second stringer portion 122) are folded to comply with the shape of the reinforcement 128. As such, each first stringer portion 120 and each second stringer portion 122 have a flange portion 124 and a vertical portion or web 126 that extends upwardly from the flange portion 124. The vertical portion or web 126 is integrally formed with the flange portion 124 such that stringer the first and second stringer portions 120 and 122 are formed as a single unitary structure.

[0123]In FIG. 12E, double sided stitching (lines 138) of the vertical portion or web 126 of the laminate of the first stringer portion 120 and the second stringer portion 122 is used to secure the vertical portion or web 126 of the stringer halves (first stringer portion 120 and the second stringer portion 122) to the reinforcement 128 to provide a reinforced stringer assembly 136.

[0124]In FIG. 12F, the reinforced stringer assembly 136 is then placed onto the B-side or non-show surface 118 of the first composite laminate or skin laminate 114 and is secured thereto with single-sided stitching (lines 140) through each flange portion 124 of the laminate of the first stringer portion 120 and the second stringer portion 122 (See at least FIG. 12G). Placement of the reinforced stringer assembly 136 can occur with the webs 126 of the stringer 112 facing either the + or −z directions as illustrated in the FIGS. 10A to 11B. Utilization of a polymer reinforcement 128 eliminates the need to use a veil to prevent displacement of the stringer 112 and the first composite laminate or skin laminate or skin 114 construction into a tooling pocket when stitching from the A-side 116 of the skin material 114, with the stringer webs 126 facing the −z direction (see at least FIG. 13). The polymer reinforcement 128 stabilizes and aids in alignment of the stringer 112 when stitching the stringer 112 to the skin material 114 from the B-side 118 of the skin material 114, with the stringer web facing the +z direction for example the orientations in FIGS. 11A, 11B and (FIG. 12G). Note: the reinforcement 128 is not illustrated in FIGS. 11A and 11B.

[0125]FIG. 13 is a view of a composite sewing head 10 sewing the composite laminates together on the A-side or show side 116 of the composite sewn part 102 with a sewing fixture 52 with channels or pockets 20 for the needles 28, 30 as well as a pocket, cavity or channel 142 in the tooling or fixture 52 for the webs 126 of the stringer 112 in accordance with the present disclosure. As mentioned above, the polymer reinforcement 128 provides support and eliminates the need to use a veil to prevent displacement of the stringer 112 and the first composite laminate or skin laminate or skin 114 construction into the tooling pocket when stitching from the A-side 116 of the skin material 114, with the stringer webs 126 facing the −z direction during the stitching process. As illustrated and in one non-limiting embodiment, one of the threads is fed through composite laminate using a needle angled 45 degrees (feed needle) to the composite laminate surface.

[0126]FIGS. 14A-14D illustrate a laminate constriction process or method in accordance with the present disclosure. FIG. 14A illustrates a first step of providing two separate Non-Crimp Fabric (NCF) composite laminate sheets 120, 122. In a second step (FIG. 14B), the two separate Non-Crimp Fabric (NCF) composite laminate sheets 120, 122 are folded to create two halves of the stringer 118.

[0127]In a third step (FIG. 14C) the folded separate Non-Crimp Fabric (NCF) composite laminate sheets 120, 122 are positioned on each side of the polymer reinforcement 128 to form a stringer assembly. The assembly is then fed through a stationary manual sewing machine 144 or the sewing machine 144 can be attached to a robot and automatically fed along the length of the stationary stringer assembly. Once stitched to the folded separate Non-Crimp Fabric (NCF) composite laminate sheets 120, 122 are stitched to the polymer reinforcement 128 a reinforced stringer assembly 136.

[0128]In step 4 (FIG. 14D), the Non-Crimp Fabric (NCF) multilaminate composite skin 114 is placed on top of the reinforced stringer assembly 136 and robotically stitched through each flange of the reinforced stringer assembly 136. Thereafter, the multilaminate composite skin 114 and the reinforced stringer assembly 136 is resin infused to create a final, cured composite. As previously mentioned, the multilaminate composite skin 114 may be secured by stitching through the A-side or show side 104 of the multilaminate composite skin 114 of the composite sewn part 102 or alternatively the B-side or non-show side 106 of the multilaminate composite skin 114 of the composite sewn part 102. In yet another alternative, the multilaminate composite skin 114 may be secured by stitching through both the A-side or show side 104 of the multilaminate composite skin 114 and the B-side or non-show side 106 of the multilaminate composite skin 114 of the composite sewn part 102.

[0129]FIG. 15A illustrates a laminate construction with no reinforcement 128. FIGS. 15B-15D illustrate a laminate construction processes in accordance with alternative embodiments of the present disclosure. In FIG. 15B, the polymer reinforcement 128 is only located between the stringer webs 126 of the first stringer portion 120 and the second stringer portion 122 separating the stringer webs 126 of the first stringer portion 120 and the second stringer portion 122 and adding a polymer reinforcement 128 along the y-z plane with reference to the axes shown in the FIGS. In FIG. 15C, the polymer reinforcement 128 is only located between the flange portions 124 of the first stringer portion 120 and the second stringer portion 122 and the B-side or non-show surface of the multilaminate composite skin 114 along the x-y plane with reference to the axes shown in the FIGS. In FIG. 15D, the polymer reinforcement 128 is similar to the configuration illustrated in FIGS. 12C and 12D-12G however, the polymer reinforcement 128 and provides reinforcement along the x-y, y-z or x-y and y-z planes with reference to the axes shown in the FIGS. and includes a polymer reinforcing rod 150 at an end of the vertical portion or web 134 of the polymer reinforcement 128. In this embodiment, the first stringer portion 120 and the second stringer portion 122 are replaced with a single stringer portion 152 which extends over the polymer reinforcing rod 150. Here the single stringer portion 152 includes both flange portions 124 and the stringer webs 126. In one embodiment, the polymer reinforcing rod 150 is separately applied to the polymer reinforcement 128 or alternatively integrally formed with the polymer reinforcement 128 when it is forced with an extruding process.

[0130]Referring now to at least FIGS. 16-26B three options for the composite sewing head design 10 in accordance with the present disclosure are illustrated in addition to a catcher needle and sleeve design and process sequence of the present disclosure. Referring now to at least FIGS. 16 and 17 a sewing head design 10 in accordance with an embodiment of the present disclosure is illustrated. The illustrated sewing head 10 illustrated in at least FIGS. 16 and 17 can be used in any of the embodiments disclosed in the present application. FIG. 16 is an end view of a composite head design 10 in accordance with an embodiment of the present disclosure and FIG. 17 is a side view of the sewing head 10 illustrated in FIG. 16. Rotatably secured to a housing 200 of the composite head design 10 is a catcher needle drive shaft 202 and a feed needle rock frame shaft 204. Also illustrated is a catcher needle rock frame shaft 206, a feed needle transport arm 208, a presser foot motor 210, a drive motor 212, a feed needle bar 214, a catcher needle bar 216, a catcher needle sleeve bar 218, and a catcher needle sleeve bar drive cam 220. A feed needle bar drive cam 222 (see at least FIG. 17) is located behind the catcher needle sleeve bar drive cam 220. Also shown is a stitching direction represented by arrow 224 and circle 225.

[0131]During operation, the feed needle rock frame shaft 204 is driven via an eccentric from the catcher needle drive shaft 202. The feed needle bar 214 is driven by a cam which is coupled to the catcher needle drive shaft 202. The catcher needle bar 216 is driven directly by the catcher needle drive shaft 202 via a crank arm mechanism 226 (See at least FIG. 17). The catcher needle sleeve bar 218 is driven by a cam that is coupled to the catcher needle drive shaft 202 via a catcher needle sleeve bar and a feed needle bar drive belt 228 and associated pulleys.

[0132]An angle of the feed needle bar 214 is adjustable (manually) by +/−5 degrees (35 to 45 degrees total) relative to catcher needle bar 216. An adjustment of 35 degrees of the feed needle bar 214 relative to catcher needle bar 216 is illustrated by arrow 230, an adjustment of 40 degrees of the feed needle bar 214 relative to catcher needle bar 216 is illustrated by arrow 232 and an adjustment of 45 degrees of the feed needle bar 214 relative to catcher needle bar 216 is illustrated by arrow 234. The head 10 illustrated in at least FIGS. 16 and 17 uses a single motor needle bar drive and the presser foot is actuated by the motor 210 which provides adjustable height compensation in real time during sewing.

[0133]As shown in at least FIGS. 16 and 17, the feed needle rock frame shaft 204 is driven via an eccentric 236 mounted to the catcher needle drive shaft 202. The feed needle bar 214 is driven by a cam which is coupled to the catcher needle drive shaft 202. The catcher needle bar 216 is driven directly by catcher needle drive shaft 202 via the crank arm mechanism 226. The catcher needle sleeve bar 218 is driven by a cam that is coupled to the catcher needle drive shaft 202 via a belt and pulleys.

[0134]As mentioned above, the angle of the feed needle bar 214 is adjustable by +/−5 degrees (35 to 45 degrees total) relative to catcher needle bar 216 and the head 10 utilizes a single motor drive 212. Also shown in at least FIG. 17 is a feed needle bar transport arm 238 and a catcher needle bar transport arm 240.

[0135]Referring now to FIG. 18 an end view of a composite head design 10 in accordance with another design of the present disclosure is illustrated. FIG. 19 is a side view of a composite head design illustrated in at least FIG. 18 in accordance with the present disclosure. The illustrated sewing head 10 illustrated in at least FIGS. 18 and 19 can be used in any of the embodiments disclosed in the present application.

[0136]Here a feed needle drive assembly 242 with a shaft, eccentric and crank assembly is driven via a feed needle drive motor 246 via a belt 248. A feed needle transport arm 250 is operably coupled to the feed needle drive assembly 242 in order to drive the feed needle rock frame drive shaft 251. Also shown is a catcher needle drive assembly 252 with a shaft, eccentric and crank assembly. The catcher needle drive assembly 252 is either driven in a single motor embodiment (motor 246) via a crank arm belt/pulley system 254 (single motor drive only) or in a dual motor embodiment without the belt/pulley system 254 wherein a catcher needle motor 256 is provided for driving the catcher needle drive assembly 252. Here a catcher needle transport arm 258 operably couples the catcher rock frame drive shaft 259 to the catcher needle drive assembly 252. As illustrated, by arrows 270 there is a 45-degree angle between the catcher and feed needles held by the catcher needle bar 216 and the feed needle bar 214.

[0137]As illustrated in FIGS. 18 and 19, the feed needle bar 214 is driven directly by the feed needle crank assembly 242 and the cam driven feed needle shaft and related linkage is eliminated. A second motor 256 can be added as an option to enable the catcher needle bar 216 and feed needle bar 214 to have independent but synchronized drive motors 246, 256. The feed needle transport is driven by an eccentric mounted to the feed needle drive shaft. The long transport arm and eccentric from the catcher needle drive shaft to the feed needle rock frame shaft is also eliminated.

[0138]The angle of the needle bars 214 and 216 relative to one another is now fixed at 45 degrees as illustrated by arrows 270.

[0139]Some advantages of the design illustrated in at least FIGS. 18 and 19 is that increased motor power transfer efficiency to the feed needle since the feed needle cam and linkage is eliminated and there is a reduced mechanical complexity. Also, the timing of the needle bars can be adjusted electronically via independent drive motors 246 and 256.

[0140]One disadvantages of this design is that there is no longer any ability to change needle angle position relative to one another without modifying the machine construction.

[0141]Referring now to at least FIG. 19, a catcher needle sleeve drive cam 272 and needle drive belt and pulleys 274 from the motors is illustrated. As illustrated in the FIG. 19, the needle drive shaft coupling belt and pulleys 276 are relocated to the rear of the head 10 for easy access. This location is only used in the single motor drive embodiment. Also shown is a catcher needle sleeve drive belt 278 and needle bar transport arms 316. Also shown is an area 280 for a thread tension and take-up mechanism 282 which includes an electronic thread tension control 284 and a thread tension sensor 286. In addition, and through additional sensors thread tension is corrected in real-time via transmission of sensor tension to computer or printed circuit board, which compares and adjusts an electronically actuated thread tensioner.

[0142]Referring now to FIG. 20, the head 10 may be positioned with a laminate thickness detection sensor 288, a quality inspection camera 290 for post-stitch detection and if required a 2D laser position scanner 294 is provided. The 2D Laser position scanner 294 for feature tracking during sewing to ensure proper stitch location and the laminate thickness detection sensor 288 to enable the machine to compensate for unanticipated laminate thickness variation during sewing. The quality inspection camera 290 for detection and documentation of defects as well as feedback for automatic machine setting compensation via the use of artificial intelligence.

[0143]Referring now to FIGS. 21 and 22 yet another alternative configuration of the sewing head 10 is illustrated. Here the feed needle bar crank assembly is eliminated and a feed needle drive cam 222 is added (similar to the head 10 as illustrated in FIGS. 16 and 17) which is driven by catcher needle drive shaft 202. A feed needle upper shaft 300 controls movement of feed needle rock frame via an eccentric 302.

[0144]The angle of the needle bars 214 and 216 relative to one another is now fixed at 45 degrees as illustrated by arrows 270. The advantages of this design is the ability to modify the feed needle bar velocity profile via a cam design as required for tuning needle-to-needle position relationship. Here the feed needle upper shaft 300 is controlled by a separate motor 246 as an option. The cams for the catcher needle sleeve drive and the feed needle bar drive can be separate and driven by their respective upper drive shafts. Also shown is a feed needle bar drive shaft 310 and a feed needle drive arm with cam follower 312. Also shown is a catcher needle sleeve and feed needle bar drive belt 314 and needle bar transport arms 316. Some of the disadvantages of this design is that the complexity of the feed needle drive mechanism is increased.

[0145]In this design, the feed needle bar crank assembly is eliminated and a feed needle cam is added as in FIGS. 16 and 17 which is driven by the catcher needle drive shaft and the feed needle upper shaft controls movement of the feed needle rock frame via an eccentric. As illustrated by arrows 270 there is a fixed angle between needle bars 214 and 216.

[0146]Referring now to FIGS. 23A-23H, a catcher needle and sleeve assembly 31 and components thereof are illustrated. FIG. 23A is view of a portion of a catcher needle 30 in accordance with the present disclosure, FIG. 23B is view of a portion of a sleeve 46 for use with the catcher needle 30 illustrated in at least FIG. 23A in accordance with the present disclosure, FIG. 23C is view of a portion of a catcher needle and sleeve assembly 31 in accordance with the present disclosure, FIG. 23D is a side view of a catcher needle and sleeve assembly 31 in accordance with the present disclosure, FIG. 23E is a front view of a catcher needle and sleeve assembly 31 in accordance with the present disclosure, FIG. 23F is a top view of a catcher needle 30 in accordance with the present disclosure, FIG. 23G is a top view of a sleeve 46 for use with the catcher needle 30 illustrated in at least FIG. 23A in accordance with the present disclosure, and FIG. 23H is a top view of a catcher needle and sleeve assembly 31 in accordance with the present disclosure.

[0147]Referring now to FIG. 24 the interaction of a catcher needle 30 and sleeve 46 for the catcher needle 30 during a stitch cycle through an article such as a composite laminate or laminates 54 is illustrated. Referring now to FIG. 24 and from left to right a first step identified as 320 of the stitch cycle is illustrated. Here the sleeve 46 is forward covering a hook 319 of the catcher needle 30 with a tongue or tab 321 and the catcher needle 30 and the sleeve 46 pass down through the material, composite laminate or laminates 54. In step two identified as 322, the sleeve 46 covering the hook 319 with tongue or tab 321 exit the material, composite laminate or laminates 54 towards bottom dead center (BDC) of travel of the catcher needle 30. In step 3 identified as 324 the sleeve 46 retracts, exposing the hook 319 and the catcher needle 30 picks up a thread near bottom dead center (BDC) of the catcher needle stroke. In step 4 identified as 326 and after picking up the thread, sleeve moves forward towards the hook 319 of the catcher needle 30 and the tongue 321 covers hook 319 as the catcher needle 30 moves upward through material, composite laminate or laminates 54. In step 5 identified as 328, the sleeve 56 is forward covering the hook 319 with tongue 321 and the catcher needle 30 and sleeve 56 move upward through material 54. In step 6 identified as 330, the catcher needle 30 approaches top dead center (TDC) and the sleeve 56 retracts exposing the hook 319, releasing the thread as the catcher needle 30 and the sleeve 56 move back downward towards the material, composite laminate or laminates 54. In step 7, identified as 332 the sleeve 46 moves forward relative to catcher needle 30 and the hook 319 is once again covered just prior to the catcher needle 30 penetration downward into the material, composite laminate or laminates 54 for the start of the next cycle beginning again at step 1 identified as 320. Alternatively, in step 7, the sleeve 46 may remain retracted relative to the catcher needle 30 and the hook 319 remains exposed as the catcher needle moves downward to and through the material, composite laminate or laminates 54 for the start of the next cycle at step 1 identified as 320.

[0148]Referring now to FIGS. 25A-26B, the needle orientation adjustment in the X-Z plane as identified in the FIGS. is illustrated.

[0149]FIG. 25A illustrates the feed and catcher needles parallel in the XZ plane with reference to the attached FIGS. In FIG. 25B the thread appearance on a top surface 55 of a stitched material, composite laminate or laminates 54 is illustrated when the feed and catcher needles are parallel in the XZ plane and a thread 334 from the feed needle 28 overlays a loop 336 of a thread from the catcher needle 30.

[0150]FIG. 26A illustrates the feed needle 28 rotated about a point of intersection 338 of the feed needle with the catcher needle by 10 degrees in the XZ plane with reference to the attached FIGS. FIG. 26B illustrates the thread appearance on the top surface 55 of the stitched material, composite laminate or laminates 54 when the feed needle 28 is rotated about the point of needle intersection 338 with the catcher needle 30 by 10 degrees in the XZ plane with reference to the attached FIGS. and the thread 334 from the feed needle 28 is offset from the catcher needle loop 336.

[0151]FIG. 25A illustrates feed and catcher needles parallel in the XZ plane with reference to the attached FIGS.

[0152]FIG. 25B illustrates the thread appearance on a top surface of a stitched material when the feed and catcher needles are parallel in the XZ plane and thread from the feed needle overlays loop from the catcher needle.

[0153]FIG. 26A illustrates the feed needle rotated about the point of intersection of the feed needle with the catcher needle by 10 degrees in the XZ plane with reference to the attached FIGS.

[0154]FIG. 26B illustrates the thread appearance on a top surface of a stitched material when the feed needle is rotated about the point of needle intersection with the catcher needle by 10 degrees in the XZ plane with reference to the attached FIGS. and the thread from the feed needle is offset from the catcher needle loop.

[0155]It is also understood that sensors 288, 290 and 294 illustrated in at least FIG. 20 can be used in any of the embodiments disclosed in the present application.

[0156]Referring to FIGS. 25A-26B, the orientation of the feed needle relative to the catcher needle is adjustable in the XZ plane (shown in FIGS. 25A-26B) so that a space between the threads formed on the top surface of the laminate can be increased or decreased accordingly. Increasing the space between the threads reduces the possibility of thread entanglement during stitching.

[0157]The angle between the catcher and feed needles can be adjustable in both the XZ (FIGS. 25A-26B) and YZ (FIGS. 4, 14) planes as illustrated in the attached FIGS. so that the sewing head 10 can be setup to manage a variety of composite material thicknesses and compositions.

[0158]In summary, a composite sewing head with feed needle bar and a catcher needle bar is disclosed herein. The feed and catcher needle interaction required to create a stitch is accomplished via a combination of linear and rotary motion of their respective needle bars. Both feed and catcher needle bars and their respective drive assemblies are located on one side of the article being stitched. Linear motion of each needle bar is accomplished by motion of a crank arm connected to a crankshaft counterweight. The crankshaft counterweight is rotated by the needle bar drive shaft. The needle bar drive shaft is rotated by a drive motor through a series of pulleys and belt(s). Rotary motion of each needle bar relative to the article being stitched is accomplished via the rotation of a needle bar rock frame. Rotation of the needle bar rock frame is accomplished via rotation of the rock frame drive shaft. Rotation of the rock frame drive shaft is accomplished via linkage connected to an eccentric mounted to the needle bar drive shaft. Motion of each needle bar drive shaft can be accomplished via a single motor or dual motors. A single motor is coupled to a second pulley on one the needle bar drive shafts. A second set of pulleys, one mounted on each needle bar drive shafts, are connected with a single belt. Timing between needle bars is accomplished via mechanical adjustment. When using dual independent motors, each motor is directed coupled to a single upper needle bar drive shaft. Timing between needle bars using independent motors can be accomplished mechanically, electrically, or a combination thereof.

[0159]The presser foot position relative to the top surface of the article being stitched is adjusted electronically via a servo motor driven linear drive rail. Position can be preset along the programmed path or adjusted in real-time during the stitching process. A catcher needle sleeve is utilized to cover the opening of the catcher needle hook during needle travel upward through the article being sewn. The sleeve is retracted, exposing the catcher needle hook and releasing the thread loop, as the catcher needle begins its stroke downward from top dead center (TDC) until shortly after moving upward from its bottom dead center (BDC) position with the feed needle thread trapped in its hook. The sleeve must remain closed over the hook while the needle retracts upward through the part. The sleeve can be closed or remain open between the time the loop is released above the part and just before reaching bottom dead center (BDC). The catcher needle sleeve is driven by a cam mounted which can be mounted to either needle bar drive shaft.

[0160]Thread tension is controlled electronically via an electronic tension regulator and tension monitor. The electronic thread tension regulator consists of a servo motor which regulates the pressure applied to the tension plates of the regulator. The tension monitor detects the actual thread tension downstream from the tension regulator and provides feedback to the control system when tension exceeds the allowable range of values. The tension sensor can also be used to provide real-time feedback to the tension regulator through the control system to maintain consistent thread tension during the sewing process.

[0161]A camera is utilized for detection and documentation of defects in the completed stitch. Information provided by the recording can also be used for automated machine adjustment when coupled with artificial intelligence.

[0162]In an alternative embodiment, linear motion of the feed needle bar can be driven via a cam mounted to the catcher needle bar drive shaft. In another alternative embodiment, rotary motion of the feed needle bar can be driven via an eccentric mounted to the catcher needle bar drive shaft. In another alternative embodiment, the angle between needle bars can be manually adjusted between 35 and 50 degrees. In another alternative embodiment, the angle of the feed and catcher needles perpendicular to the needle plane can be adjusted to increase the distance between the two stitch paths created on the top surface the article being sewn. The angular adjustment also provides clearance between the thread loops created on the bottom surface of the part, eliminating any opportunity for the feed needle to piece the loop created from the prior stitch during its downward travel.

[0163]The term “about” is intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application. For example, “about” can include a range of ±8% or 5%, or 2% of a given value.

[0164]The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. 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, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, element components, and/or groups thereof.

[0165]While the present disclosure has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this present disclosure, but that the present disclosure will include all embodiments falling within the scope of the claims.