Method and apparatus for automatic decorative stitching
A robotic sewing head with chain stitching technology addresses the challenge of sewing decorative stitches on complex 3D automotive parts by automating the process, ensuring efficient stitching on intricate shapes.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- INTEVA PRODUCTS LLC
- Filing Date
- 2023-07-03
- Publication Date
- 2026-07-09
AI Technical Summary
Manual sewing of decorative stitches on 3D-formed automotive parts becomes increasingly difficult and sometimes impossible as the size and shape complexity of the parts increase, especially for instrument panels, necessitating automation.
A robotic sewing head utilizing chain stitching technology mounted on a 6-axis robot, with a decorative chain stitch head that includes an upper and lower head assembly, and a needle bar cam assembly, capable of producing decorative stitches on 3D molded parts without frequent bobbin changes.
Enables automated decorative stitching on complex 3D parts, providing access to all areas of pre-formed automotive trim components and reducing the need for manual intervention.
Smart Images
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Abstract
Description
Cross - reference to related applications
[0001]
[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 357,644, filed on July 1, 2022, the content of which is incorporated herein by reference.
Technical Field
[0002]
[0002] Exemplary embodiments of the present disclosure relate to methods and apparatuses for sewing decorative stitches onto the surface of three - dimensional parts.
Background Art
[0003]
[0003] Decorative stitches for automotive trim materials and parts are available. Decorative stitches typically refer to patterns that have some lateral movement of the stitch in addition to forward movement.
[0004]
[0004] Under current state - of - the - art, when decorative stitches are desired on an automotive trim panel, the stitches are applied via an operator who supports and guides the part as it is fed into a manually - modified machine that is adjusted to produce any number of different decorative patterns. The material to be sewn can be either flat or pre - formed. If pre - formed, the size and shape of the part and the location of the sewing path on the part must be such that a human operator can control the placement of the stitches relatively easily.
[0005]
[0005] Many sewing machine manufacturers offer manual sewing machines used to apply decorative stitches to trim materials. Manual machines built for such stitches may be of the flatbed or postbed type. Manual flatbed sewing machines are primarily used to sew flat materials used in the cut-sew-wrap process to cover trim components. Manual postbed sewing machines are often used to sew parts that have gained some shape from two components, such as seams sewn in a previous process step. The post allows decorative stitches to be applied to a part without the need to flatten the entire part, as is the case with a regular flatbed sewing machine. However, as the size and / or shape of the part increases, manual sewing of such parts becomes more difficult.
[0006]
[0006] Recent customer requests include the placement of decorative stitching on 3D-formed automotive parts. As the size and shape complexity of the parts increase, manual sewing of such parts becomes more difficult, and sometimes impossible, especially in the case of instrument panels, and the need for automation increases.
[0007]
[0007] Brief explanation This specification discloses a method and apparatus for robotically sewing decorative stitches onto the surface of a 3D molded part. The decorative stitch sewing head utilizes chain stitching technology to eliminate the need for frequent bobbin changes.
[0008]
[0008] Taking into account the need to modify the lower bobbin and redesign the post assembly to accommodate the hook instead of the looper, lockstitch technique can also be used.
[0009]
[0009] The sewing head is mounted as an end effector on a 6-axis robot, which is responsible for positioning the sewing head relative to the part to be sewn as needed.
[0010]
[0010] Alternatively, the sewing head can be kept stationary while the robot positions the part relative to the sewing head in order to perform the stitching process.
[0011]
[0011] A decorative chain stitch head is disclosed, comprising: an upper head assembly that controls the movement of a needle bar and a walking foot mechanism; a walking foot eccentric configured to allow adjustment of the foot lift, while a stitch length eccentric configured to allow adjustment of both walking foot forward and needle bar forward via adjustment of a oscillating frame that determines the length of the stitch produced by the decorative chain stitch head; a lower head assembly; and a needle bar cam assembly that drives the rotation of the needle bar during each stitch cycle of the decorative chain stitch head to achieve a desired stitch pattern, and is directly driven by the upper shaft via a pair of gears that reduce the speed of the needle bar cam assembly according to the size ratio of the pair of gears.
[0012]
[0012] In addition to one or more of the features described above, or as an alternative to any of the embodiments described above, two different cam profiles are machined onto the needle bar cam assembly.
[0013]
[0013] In addition to one or more of the above-described features, or as an alternative to any of the above-described embodiments, the cam follower engages with one of two different cam profiles and drives a linkage mechanism that connects to a drive gear.
[0014]
[0014] In addition to one or more of the above-described features, or as an alternative to any of the embodiments described above, the lateral movement of the link mechanism is controlled by two bearing blocks that engage with the guide rail.
[0015]
[0015] Disclosed is a decorative chain stitch head comprising: an upper head assembly that controls the movement of a needle bar and a walking foot mechanism, the upper head assembly having a pair of needles in the needle bar; and a lower head assembly comprising a pair of spreaders, each having a scarf facing each other, and a pair of spreaders, the lower head assembly being configured to cause the pair of loopers to move toward and away from the pair of spreaders during a stitch sequence of the decorative chain stitch head, the lower head assembly being configured to cause the pair of spreaders to move toward and away from each other during a stitch sequence of the decorative chain stitch head.
[0016]
[0016] In addition to one or more of the features described above, or as an alternative to any of the embodiments described above, a pair of needles are received in a pair of loopers during the stitching sequence of a decorative chain stitch head.
[0017]
[0017] In addition to one or more of the features described above, or as an alternative to any of the embodiments described above, the lower head assembly further comprises a pair of concentric shafts, one of which is rotatably fixed to one another such that one of the concentric shafts rotates around the other of the concentric shafts and the other of which rotates within one of the concentric shafts, such that the rotation of the concentric shafts relative to each other causes the pair of spreaders to move toward and away from each other during the stitching sequence of the decorative chain stitch head, with one of the concentric shafts operably fixed to one of the pair of spreaders and the other of the concentric shafts fixed to the other of the pair of spreaders.
[0018]
[0018] In addition to one or more of the above-described features, or as an alternative to any of the above-described embodiments, the pair of concentric shafts are rotated by a spreader cam that engages with a spreader cam follower directly connected to a bearing block, and the rotation of the spreader cam causes the pair of concentric shafts to rotate relative to each other.
[0019]
[0019] In addition to one or more of the above-described features, or as an alternative to any of the embodiments described above, the bearing block rests on the guide rail.
[0020]
[0020] In addition to one or more of the features described above, or as an alternative to any of the embodiments described above, the bearing block further includes a pin that serves as a hub for rotatably receiving one end of each of a pair of connecting rods, the opposite end of each of the pair of connecting rods being rotatably fixed to one of a pair of crank arms, one of the pair of crank arms being fixed to one of a pair of concentric shafts, and the other of the pair of crank arms being fixed to the other of the pair of concentric shafts.
[0021]
[0021] In addition to one or more of the above-described features, or as an alternative to any of the embodiments described above, the linear movement of the bearing block causes the rotational movement of the pair of concentric shafts relative to each other.
[0022]
[0022] Disclosed is a method for providing stitches to a part using a decorative chain stitch head, comprising the steps of: moving a pair of needles up and down using an upper head assembly; engaging the upper thread of each of the pair of needles with a pair of loopers of a lower head assembly during a stitch sequence of the decorative chain stitch head, wherein each of the loopers has a scarf facing each other; and engaging the lower thread of each of the pair of loopers with a pair of spreaders during a stitch sequence of the decorative chain stitch head, wherein the lower head assembly moves the pair of loopers toward and away from the pair of spreaders during a stitch sequence of the decorative chain stitch head, and the lower head assembly moves the pair of spreaders toward and away from each other during a stitch sequence of the decorative chain stitch head.
[0023]
[0023] In addition to one or more of the features described above, or as an alternative to any of the embodiments described above, a pair of needles are received in a pair of loopers during the stitching sequence of a decorative chain stitch head.
[0024]
[0024] In addition to one or more of the features described above, or as an alternative to any of the embodiments described above, the lower head assembly further comprises a pair of concentric shafts, which are rotatably fixed to each other such that one of the pair of concentric shafts rotates around the other of the pair of concentric shafts and the other of the pair of concentric shafts rotates within one of the pair of concentric shafts, such that the rotation of the pair of concentric shafts relative to each other causes the pair of spreaders to move toward and away from each other during the stitch sequence of the decorative chain stitch head, with one of the pair of concentric shafts operably fixed to one of the pair of spreaders and the other of the pair of concentric shafts fixed to the other of the pair of spreaders.
[0025] In addition to one or more of the above features, or as an alternative to any of the foregoing embodiments, a pair of concentric shafts is rotated by a spreader cam that engages a spreader cam follower directly connected to a bearing block, and rotation of the spreader cam causes relative rotation of the pair of concentric shafts with respect to each other.
[0026] In addition to one or more of the above features, or as an alternative to any of the foregoing embodiments, the bearing block rides on a guide rail.
[0027] In addition to one or more of the above features, or as an alternative to any of the foregoing embodiments, the bearing block further includes a pin that serves as a hub for rotatably receiving one end of each of a pair of connecting rods, and the opposite ends of each of the pair of connecting rods are rotatably fixed to one of a pair of crank arms, one of the pair of crank arms is fixed to one of the pair of concentric shafts, and the other of the pair of crank arms is fixed to the other of the pair of concentric shafts.
[0028] In addition to one or more of the above features, or as an alternative to any of the foregoing embodiments, linear movement of the bearing block causes relative rotational movement of the pair of concentric shafts with respect to each other.
[0029] In addition to one or more of the above features, or as an alternative to any of the foregoing embodiments, movement of the pair of loopers and the pair of spreaders is restricted to a region defined by a stitch plate having a width of 35 mm or less and a length of 56 mm or less during the stitch sequence of a decorative chain stitch head.
[0030] In addition to one or more of the above features, or as an alternative to any of the foregoing embodiments, a pair of needles is received within a pair of loops during the stitch sequence of a decorative chain stitch head, and the lower head assembly further comprises a pair of concentric shafts that are rotatably fixed to each other such that one of the pair of concentric shafts rotates about the other of the pair of concentric shafts and the other of the pair of concentric shafts rotates within the one of the pair of concentric shafts, and the rotation of the pair of concentric shafts relative to each other causes a movement of a pair of spreaders towards each other and a movement away from each other during the stitch sequence of the decorative chain stitch head, wherein one of the pair of concentric shafts is operably fixed to one of the pair of spreaders and the other of the pair of concentric shafts is fixed to the other of the pair of spreaders.
[0031] The following description should not be regarded as in any way limiting. Referring to the accompanying drawings, like elements are numbered alike.
Brief Description of the Drawings
[0032] [Figure 1] A perspective view of a decorative chain stitch head according to the present disclosure. [Figure 2] A perspective view of the upper head assembly of the decorative chain stitch head shown in FIG. 1. [Figure 3] An enlarged perspective view of at least a part of the upper head assembly of the decorative chain stitch head shown in FIG. 2. [Figure 3A] A stitch pattern that can be produced with a decorative chain stitch head according to the present disclosure is shown. [Figure 4] A perspective view of the lower head assembly of the decorative chain stitch head shown in FIG. 1. [Figure 5] An enlarged perspective view of at least a part of the lower head assembly of the decorative chain stitch head shown in FIG. 4. [Figure 6]This is an enlarged perspective view of at least a portion of the lower head assembly of the decorative chain stitch head shown in Figure 4. [Figure 7A] This disclosure shows the stitch formation cycle. [Figure 7B] This disclosure shows another stitch formation cycle. [Figure 7C] This disclosure shows yet another stitch formation cycle. [Figure 7D] This disclosure shows yet another stitch formation cycle. [Figure 7E] This disclosure shows yet another stitch formation cycle. [Figure 7F] This disclosure shows yet another stitch formation cycle. [Figure 7G] This disclosure shows yet another stitch formation cycle. [Figure 7H] This disclosure shows yet another stitch formation cycle. [Figure 8] The upper part of the stitch plate of the lower head assembly of this disclosure is shown. [Figure 9A] The image shows a top view of the stitch formation cycle according to this disclosure. [Figure 9B] A top view of another stitch formation cycle according to this disclosure is shown. [Figure 9C] A top view of yet another stitch formation cycle according to this disclosure is shown. [Figure 9D] A top view of yet another stitch formation cycle according to this disclosure is shown. [Figure 9E] A top view of yet another stitch formation cycle according to this disclosure is shown. [Figure 9F] A top view of yet another stitch formation cycle according to this disclosure is shown. [Figure 9G] A top view of yet another stitch formation cycle according to this disclosure is shown. [Figure 9H] A top view of yet another stitch formation cycle according to this disclosure is shown. [Modes for carrying out the invention]
[0033]
[0041] A detailed description of one or more embodiments of the disclosed apparatus and method is presented herein as an example, not an limitation, with reference to the drawings.
[0034]
[0042] As mentioned above, when decorative stitching is desired on automotive trim panels, manual stitching of such parts becomes more difficult as the size and / or shape of the parts increases. Therefore, especially in the case of instrument panels, as the complexity of the part size and shape increases, manual stitching of such parts becomes more difficult, sometimes impossible, and the need for automation increases.
[0035]
[0043] This specification discloses a method and apparatus for robotically sewing decorative stitching onto the surface of a 3D molded part. Non-limiting examples of three-dimensional parts include the interior of a vehicle, the instrument panel of a vehicle, any automotive interior surface, or any other part where access to the opposite side of the item being sewn is restricted due to the composition of the part or panel to be sewn. The part or panel to be sewn may consist of several layers or only a single layer, and in one embodiment, the part or panel may have a display surface having a substantially smooth outer surface and a bottom surface facing away from the outer surface. The display surface may be formed from a substantially flexible and aesthetically pleasing plastic material, vinyl, thermoplastic olefin (TPO), leather, and the like.
[0036]
[0044] To enhance the flexibility of a part or panel, a layer of cushioning support material may be added to the part or panel before or after it is sewn. The part or panel may also include a substrate panel of dimensionally stable plastic or other suitable material that is applied before or after the stitching process. Furthermore, in one embodiment, the part or panel may consist of only a single layer structural panel.
[0037]
[0045] The decorative stitch sewing head utilizes chain stitch technology to eliminate the need for frequent bobbin changes.
[0038]
[0046] Considering the need to modify the lower bobbin and redesign the post assembly to accommodate the hook instead of the looper, lockstitch technique can also be utilized.
[0039]
[0047] The sewing head is mounted as an end effector on a 6-axis robot, which is responsible for positioning the sewing head relative to the part being sewn as needed.
[0040]
[0048] Alternatively, the sewing head can be kept stationary while the robot positions the part relative to the sewing head for the stitching process.
[0041]
[0049] Figure 1 is a perspective view of the decorative chain stitch head according to this disclosure.
[0042]
[0050] Figure 2 is a perspective view of the upper head assembly of the decorative chain stitch head shown in Figure 1.
[0043]
[0051] Figure 3 is an enlarged perspective view of at least a portion of the upper head assembly of the decorative chain stitch head shown in Figure 2.
[0044]
[0052] Figure 3A shows a stitch pattern that can be produced with the decorative chain stitch head according to this disclosure.
[0045]
[0053] Figure 4 is a perspective view of the lower head assembly of the decorative chain stitch head shown in Figure 1.
[0046]
[0054] Figure 5 is an enlarged perspective view of at least a portion of the lower head assembly of the decorative chain stitch head shown in Figure 4.
[0047]
[0055] Figure 6 is an enlarged perspective view of at least a portion of the lower head assembly of the decorative chain stitch head shown in Figure 4.
[0048]
[0056] Figures 7A to 7H show the stitch formation cycle according to this disclosure.
[0049]
[0057] Figure 8 shows the upper part of the stitch plate of the lower head assembly of the present disclosure.
[0050]
[0058] Figures 9A to 9H show top views of the stitch formation cycle according to this disclosure.
[0051]
[0059] Referring to Figure 1, a decorative chain stitch sewing head 100 of the present disclosure is shown. According to embodiments of the present disclosure, the decorative chain stitch sewing head 100 is intended for use as the head of a robotic stitching machine. In one embodiment, the decorative chain stitch sewing head 100 is mounted as an end effector on a 6-axis robot 101 (shown in the photograph) which is responsible for positioning the sewing head 100 relative to the part to be sewn as needed. Alternatively, the sewing head can be left stationary while the robot positions the part relative to the sewing head 100 for the stitching process to be performed. The decorative chain stitch sewing head 100 includes an upper head assembly 1 and a lower head assembly 2.
[0052]
[0060] As shown in Figure 2, the upper head assembly 1 controls the movement of the needle bar 3 and walking foot 4 mechanism. The walking foot eccentric part 5 allows for adjustment of the foot lift, and the stitch length eccentric part 6 allows for adjustment of both the walking foot advance and the needle bar advance via adjustment of the oscillating frame 6a which determines the stitch length.
[0053]
[0061] The needle bar cam assembly 7 drives the rotation of the needle bar 3 around axis A during each stitch cycle to achieve the desired stitch pattern 8 shown in Figure 3A. The needle bar cam 7 is driven directly by the upper shaft 9 via a pair of gears 10a, 10b that reduce the cam speed according to the size ratio of the two gears 10a, 10b. Two different cam profiles 11a, 11b are machined into the cam shown in Figure 3. Other profiles can be added to and integrated with the illustrated profile, or they can replace existing cams located within the sewing head.
[0054]
[0062] The cam follower 12 engages with one of two cam profiles 11a, 11b, and then drives a link mechanism 13 connected to the cam follower 12 at one end, and the link mechanism 13 is connected to the drive gear 14 at the other end via a pin 50 such that the linear movement of the link mechanism in the direction of arrow 52 allows for the rotational movement of the gear 50. The smooth lateral movement of the link mechanism 13 in the direction of arrow 52 is controlled by two bearing blocks 15 that engage with a guide rail 16 that slides between the two bearing blocks 15. In Figure 2, a portion of the guide rail 16 is shown as a dashed line. The bearing blocks 15 are fixed to a block 102 which is fixed to the link mechanism 13 and the cam follower 12. The drive gear 14 engages with the drive gear 17, which surrounds and is fixed to the needle bar 3, and thus rotates the needle bar 3 around axis A as directed by the selected cam gear profiles 11a, 11b during machine operation (for example, rotation of shaft 9 by a motor or other device operably connected to shaft 9).
[0055]
[0063] Alternatively, the rotation of the needle bar can be controlled by pneumatic or electrical action instead of the aforementioned cam.
[0056]
[0064] The lower head assembly 2, shown in Figure 4, incorporates a post assembly 18 that houses the looper drive mechanism 19 and the spreader shaft assembly 20. The looper cam 21 controls all rotational movement of the looper arm 51, which is rotatably fixed to the shaft 53. The looper arm 51 engages with the looper cam 21 at one end and is fixed to a pair of loopers 31 at the other end of the looper arm 51. Thus, the position of the loopers 31 and the acceleration and deceleration of the loopers are controlled by the rotation of the looper cam 21. The looper cam 21 is driven directly from a belt 56 (shown by a dashed line) operably connected to the lower arm shaft 22 and the looper cam 21. The lower arm shaft 22 is rotated by a motor or other equivalent device operably connected to the lower arm shaft 22. Therefore, the rotation of the looper cam 21 causes the movement of the looper 31 via the movement of the looper arm 51 (for example, the cam drive of the looper arm 51 engages with the cam path of the looper cam 21 when the looper cam 21 is rotated, and thus the looper arm 51 rotates around the shaft 53 when the looper cam 21 is rotated, changing the position of the looper 31).
[0057]
[0065] In Figure 5, the spreader shaft assembly 20 includes a pair of concentric or spreader shafts 20a, 20b that are fixed to rotate relative to each other (for example, shaft 20b is positioned around shaft 20a, and shaft 20b rotates around shaft 20a). In other words, shaft 20a has an outer circumference that is slightly smaller than the inner diameter of the inner opening of shaft 20b into which shaft 20a is received. Both shafts 20a, 20b are driven by a spreader cam 23 located at the base of a post on the lower shaft. The spreader cam 23 engages with a spreader cam follower 24, which is directly connected to a bearing block 25 that sits on a guide rail 26, to ensure smooth linear operation.
[0058]
[0066] At the top of the bearing block 25 in Figure 6, there is a pin 27 that acts as a hub for rotatably receiving one end of a pair of connecting rods 28. The other end of each of the pair of connecting rods 28 is rotatably or operably connected to one of a pair of crank arms 29, one of the pair of crank arms 29 is fixed to one of a pair of concentric shafts 20a, 20b, and the other of the pair of crank arms 29 is connected to the other of the pair of concentric shafts 20a, 20b. Thus, the pair of crank arms 29 and the pair of connecting rods 28 operably connect the pair of concentric shafts 20a, 20b to the spreader cam 23 such that the rotation of the spreader cam 23 causes the pair of concentric shafts 20a, 20b to rotate relative to each other in the directions of arrows 53, 55. Therefore, the linear motion of the bearing block 25 in the direction of arrow 57 via the pin 24 that engages with the spreader cam 23 is converted into rotational motion of each spreader shaft 20a, 20b or each concentric shaft 20a, 20b in opposite directions. This rotational movement of the spreader shafts 20a, 20b also causes rotation of the spreader 30 fixed to the opposite ends of the concentric shafts 20a, 20b.
[0059]
[0067] A description of a stitch-forming cycle using the decorative chain stitch sewing head 100 of the present disclosure is shown at least in Figures 7A to 7H. Figure 7A shows a needle 32 in the bottom dead center (BDC) position and a looper 31 in a retracted or rearward position, and the spreader 30 is fully open (e.g., completely separated from each other) at the start of the stitch cycle. During the stitch cycle, it is understood that the looper 31 moves between the rearward and forward positions, while the spreader 30 moves between the fully open position and a closed position in which the spreaders 30 are closer to each other than in the fully open position. It is understood that the spreaders do not need to be in contact with each other when in the closed position.
[0060]
[0068] In Figure 7B, the needle 32 begins to move upward in the direction of arrow 70, while the looper 31 moves forward from its rear position in Figure 7A (for example, by rotation of the looper cam 21) in the direction of arrow 72 to pick up the upper stitch thread or upper thread 33 from each of the needles 32 (for example, each needle 32 has an upper stitch or upper thread 33). During this movement, the spreader 30 remains stationary in the open position.
[0061]
[0069] Figure 7C shows the looper 31 in the fully forward position in the direction of arrow 72, with the upper threads 33 and spreader 30 still in the fully open position. As the needle 32 approaches the top dead center (TDC) position, it begins to rotate around the needle bar axis 3a (by the rotation of gears 14 and 17 as described above). At this point, each upper thread or upper thread 33 is looped around the rear end of its respective looper 31, the looper moves to the fully forward position, and the spreader 30 begins to close around its respective lower thread 34.
[0062]
[0070] In Figure 7D, the rotation of the needle is complete when the needle 32 moves downward from the top dead center (TDC) position in the opposite direction to arrow 70. Here, the spreader 30 is closed (for example, by the rotation of the spreader shafts 20a, 20b or concentric shafts 20a, 20b as described above), moving toward each other in the direction of arrow 76, and drawing the bottom thread 34 from each looper 31 (for example, each looper 31 supplies the bottom thread 34)). Here, both loopers 31 are still in the fully forward position. Since one of the shafts 20a, 20b is fixed to one of the spreader 30 and the other of the shafts 20a, 20b is fixed to the other of the spreader 30, the rotational movement of each spreader shaft or concentric shaft 20a, 20b toward each other facilitates the movement of the spreader 30 toward and away from each other. Therefore, the rotation of shafts 20a and 20b causes the spreaders 30 to move toward and away from each other.
[0063]
[0071] Figure 7E shows each needle 32 moving downward through the triangle created between each looper 31 and each bottom thread 34. Here, the top thread 33 is still wrapped around the looper 31 as it begins to move backward in the opposite direction to arrow 72 from at least the fully forward position of the looper 31 shown in Figure 7C. Here, the spreader 30 is fully closed and holds the bottom thread 34 (for example, the hook portion at the distal end of each spreader 30 engages with each of the bottom threads 34 provided by each looper 31).
[0064]
[0072] In Figure 7F, the needle 32 approaches the bottom dead center (BDC), while the looper 31 moves backward until the upper thread 33 is released from the tip or distal end of the looper 31. At this point, the spreaders 30 remain closed or close to each other, with each lower or bottom thread 34 held by the respective spreaders 30 of the pair of spreaders.
[0065]
[0073] In Figure 7G, the spreader 30 moves in the opposite direction to arrow 76 until the bobbin thread 34 is released from the tip or distal end of the spreader 30, thereby completing the stitch. The looper 31 continues to move backward in the opposite direction to arrow 72, while the spreader 30 moves towards the fully open position in the opposite direction to arrow 76, and the needle 32 is at the bottom dead center (BDC) position.
[0066]
[0074] In Figure 7H, the looper 31 is fully retracted, the spreader 30 is fully open, the needle 32 remains in the bottom dead center (BDC) position, and the next stitch cycle is ready to begin, when the needle 32 will start moving upward again in the direction of arrow 70.
[0067]
[0075] Figure 8 shows a top view of the stitch plate 36 of the decorative chain stitch sewing head 100. The diagram shown in Figure 8 is one of the positions in the stitch sequence described above. As shown, the loopers 31 are configured and positioned so that the scarves 35 of each looper 31 face each other (for example, in the direction of arrows 104, 106, as opposed to both scarves 35 facing the same direction of arrow 104 or 106). This looper orientation allows both needles 32 to pass inside each looper 31 or between both loopers 31, as shown in the figure. In contrast, with scarves 35 facing the same direction, only one needle 32 passes between the two loopers, and the other needle 32 must engage with the other scarf 35 which faces the same direction as the other scarf 35. The spreader 30 rotates in opposite directions relative to each other (e.g., inward and outward, or open and closed) in the direction of arrow 82, rather than in the same direction laterally in front of the tips of the loopers 31, which is required when the scarves 35 face the same direction, as opposed to each other according to this disclosure. In other words, in this disclosure, the scarves 35 face each other (e.g., opposite faces), as opposed to scarves 35 facing the same general direction. This configuration, combined with rotating concentric spreader shafts 20a, 20b, minimizes package space requirements at the top of the lower post.
[0068]
[0076] It is also shown that the looper 31 moves between a rear position and a front position in the direction of arrow 108.
[0069]
[0077] In one embodiment, considering the configuration of the present disclosure, the width "W" × length "L" of the stitch plate 36 can be 35 mm × 56 mm or less so that the stitch plate 36 passes through a limited or small area of a three-dimensional part during sewing. This configuration also eliminates the tendency for the thread to unravel during sewing.
[0070]
[0078] While the aforementioned configuration with a width "W" of 35 mm and a length "L" of 56 mm has been shown to yield the desired results, this disclosure also intends to explore the possibility of using smaller or larger dimensions than those described above.
[0071]
[0079] The frequency of needle bar rotation and the use of a 1:2 needle ratio indicate the type of stitch pattern produced.
[0072]
[0080] Referring to Figures 9A to 9H, a top view of the stitch formation cycle according to this disclosure is shown.
[0073]
[0081] In Figure 9A, the needle 32 is at the bottom dead center, the looper 31 is retracted, and the spreader 30 is open. In Figure 9B, the needle 32 moves upward, the looper 31 moves forward to engage with the upper thread 33, and the spreader 30 remains in the open position. In Figure 9C, the needle 32 rotates around the needle bar 3 as it moves upward toward the top dead center to create the desired stitch pattern, the looper 31 moves to its fully forward position, and the upper thread 33 is looped around the rear end of the looper 31. Furthermore, the spreader 30 moves toward each other in the direction of arrow 82 and engages with the lower thread 34.
[0074]
[0082] In Figure 9D, the needle 32 completes its rotation as it begins its downward movement. Here, the looper 31 is fully forward, and the spreader 30 closes around each bobbin thread 34, pulling the bobbin thread 34 out of each looper 31. In Figure 9E, the needle 32 is moving downward between the triangles 135 created between the bobbin thread 34 and each arm of the looper 31, the looper 31 begins its backward movement, and the upper thread 33 is still wrapped around the looper 31. Here, the spreader 30 is closed, and each bobbin thread 34 is still held by the tip of the spreader 30.
[0075]
[0083] In Figure 9F, the needle 32 is near the bottom dead center, the looper 31 continues to move backward, releasing each upper thread 33, the spreader 30 remains closed, and each lower thread 34 is held.
[0076]
[0084] In Figure 9G, the needle 32 is at its bottom dead center, and the looper 31 is moving backward in the direction of arrow 109. The spreader 30 is open, releasing each bobbin thread 34 from the spreader tip, thereby completing the stitch.
[0077]
[0085] In Figure 9H, the needle 32 remains at the bottom dead center, the looper 31 is in the rearward position, and the spreader 30 is fully open, ready to begin the next stitch cycle.
[0078]
[0086] By eliminating components and simplifying the needle bar rotation and spreader drive systems, this robotic sewing head design becomes compact enough to provide access to stitch almost all of the most distant areas of pre-formed automotive trim components.
[0079]
[0087] The term "approximately" is intended to include the degree of error associated with the measurement of a particular quantity based on the equipment available at the time of filing. For example, "approximately" may include a range of ±8%, 5%, or 2% of a given value.
[0080]
[0088] The terms used herein are intended solely to describe specific embodiments and are not intended to limit the disclosure. Where used herein, the singular forms “a,” “an,” and “the” are intended to include the plural form unless the context clearly indicates otherwise. Where used herein, the terms “comprises” and / or “comprising” specify the presence of the described features, integers, steps, actions, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, actions, elements, components, and / or groups thereof.
[0081]
[0089] While this disclosure has been described with reference to one or more exemplary embodiments, those skilled in the art will understand that various modifications can be made and elements can be substituted with equivalents without departing from the scope of this disclosure. Furthermore, many modifications can be made to adapt the teachings of this disclosure to specific circumstances or materials without departing from the essential scope of this disclosure. Thus, this disclosure is not limited to any particular embodiment disclosed as the best mode intended for carrying out this disclosure, and this disclosure is intended to include all embodiments that fall within the claims.
Claims
1. A decorative chain stitch head, An upper head assembly that controls the movement of the needle bar and walking foot mechanism, The stitch length eccentric section is configured to allow adjustment of both walking foot advance and needle bar advance via adjustment of a oscillating frame that determines the length of the stitch produced by the decorative chain stitch head, while the walking foot eccentric section is configured to allow adjustment of the foot lift, Lower head assembly, A pair of loopers, each having a scarf facing the other, A pair of spreaders, wherein the lower head assembly is configured to cause movement of a pair of loopers toward and away from the pair of spreaders during the stitch sequence of the decorative chain stitch head, and the lower head assembly is configured to cause movement of the pair of spreaders toward and away from each other during the stitch sequence of the decorative chain stitch head, The lower head assembly, A needle bar cam assembly that drives the rotation of the needle bar during each stitch cycle of the decorative chain stitch head to achieve a desired stitch pattern, the needle bar cam assembly being driven directly by an upper shaft via a pair of gears that reduce the speed of the needle bar cam assembly according to the size ratio of the pair of gears, A decorative chain stitch head equipped with [a specific feature].
2. The decorative chain stitch head according to claim 1, wherein two different cam profiles are machined into the needle bar cam assembly.
3. The decorative chain stitch head according to claim 2, wherein a cam follower engages with one of the two different cam profiles and drives a linkage mechanism connected to a drive gear.
4. The decorative chain stitch head according to claim 3, wherein the lateral movement of the link mechanism is controlled by two bearing blocks that engage with a guide rail.
5. A decorative chain stitch head, An upper head assembly that controls the movement of a needle bar and a walking foot mechanism, wherein the needle bar has a pair of needles, Lower head assembly, A pair of loopers, each having a scarf facing the other, A pair of spreaders, wherein the lower head assembly is configured to cause movement of a pair of loopers toward and away from the pair of spreaders during the stitch sequence of the decorative chain stitch head, and the lower head assembly is configured to cause movement of the pair of spreaders toward and away from each other during the stitch sequence of the decorative chain stitch head, The lower head assembly, A decorative chain stitch head equipped with [a specific feature].
6. The decorative chain stitch head according to claim 5, wherein the pair of needles are received within the pair of loopers during the stitch sequence of the decorative chain stitch head.
7. The lower head assembly further comprises a pair of concentric shafts, each pair being rotatably fixed to one another such that one of the pair rotates around the other of the pair of concentric shafts, and the other of the pair of concentric shafts rotates within the one of the pair of concentric shafts, wherein one of the pair of concentric shafts is operably fixed to one of the pair of spreaders, and the other of the pair of concentric shafts is fixed to the other of the pair of spreaders, such that the rotation of the pair of concentric shafts relative to one another causes the pair of spreaders to move toward and away from each other during the stitching sequence of the decorative chain stitch head.
8. The decorative chain stitch head according to claim 7, wherein the pair of concentric shafts are rotated by a spreader cam that engages with a spreader cam follower directly connected to a bearing block, and the rotation of the spreader cam causes the pair of concentric shafts to rotate relative to each other.
9. The decorative chain stitch head according to claim 8, wherein the bearing block rests on a guide rail.
10. The decorative chain stitch head according to claim 8, wherein the bearing block further comprises a pin that acts as a hub for rotatably receiving one end of each of a pair of connecting rods, the opposite ends of each of the pair of connecting rods being rotatably fixed to one of a pair of crank arms, one of the pair of crank arms being fixed to one of the pair of concentric shafts, and the other of the pair of crank arms being fixed to the other of the pair of concentric shafts.
11. The decorative chain stitch head according to claim 10, wherein the linear movement of the bearing block causes the rotational movement of the pair of concentric shafts relative to each other.
12. A method for providing stitches to a part using a decorative chain stitch head, The steps include moving a pair of needles up and down using the upper head assembly, A step of engaging the upper thread of each of the pair of needles with a pair of loopers of the lower head assembly during the stitching sequence of the decorative chain stitch head, wherein each of the pair of loopers has a scarf facing each other. A step of engaging the bobbin thread of each of the pair of loopers with a pair of spreaders during the stitch sequence of the decorative chain stitch head, wherein the lower head assembly moves the pair of loopers toward and away from the pair of spreaders during the stitch sequence of the decorative chain stitch head, and the lower head assembly moves the pair of spreaders toward and away from each other during the stitch sequence of the decorative chain stitch head. Methods that include...
13. The method according to claim 12, wherein the pair of needles are received in the pair of loopers during the stitching sequence of the decorative chain stitch head.
14. The method according to claim 12, wherein the lower head assembly further comprises a pair of concentric shafts, one of which rotates around the other of the pair of concentric shafts and the other of which rotates within the one of the pair of concentric shafts, and one of which is operably fixed to one of the pair of spreaders and the other of which is fixed to the other of the pair of spreaders, such that the rotation of the pair of concentric shafts relative to each other causes the pair of spreaders to move toward and away from each other during the stitching sequence of the decorative chain stitch head.
15. The method according to claim 14, wherein the pair of concentric shafts are rotated by a spreader cam that engages with a spreader cam follower directly connected to a bearing block, and the rotation of the spreader cam causes the pair of concentric shafts to rotate relative to each other.
16. The method according to claim 15, wherein the bearing block rests on a guide rail.
17. The method according to claim 15, wherein the bearing block further comprises a pin that acts as a hub for rotatably receiving one end of each of a pair of connecting rods, the opposite ends of each of the pair of connecting rods being rotatably fixed to one of a pair of crank arms, one of the pair of crank arms being fixed to one of the pair of concentric shafts, and the other of the pair of crank arms being fixed to the other of the pair of concentric shafts.
18. The method according to claim 17, wherein the linear movement of the bearing block causes the rotational movement of the pair of concentric shafts relative to each other.
19. The method according to claim 12, wherein the movement of the pair of loopers and the pair of spreaders is restricted during the stitch sequence of the decorative chain stitch head to an area defined by a stitch plate having a width of 35 mm or less and a length of 56 mm or less.
20. The method according to claim 12, wherein the pair of needles are received in the pair of loopers during the stitch sequence of the decorative chain stitch head, and the lower head assembly further comprises a pair of concentric shafts, one of which is fixed rotatably to each other such that one of the pair of concentric shafts rotates around the other of the pair of concentric shafts and the other of the pair of concentric shafts rotates within the one of the pair of concentric shafts, and the rotation of the pair of concentric shafts relative to each other causes the pair of spreaders to move toward and away from each other during the stitch sequence of the decorative chain stitch head, with one of the pair of concentric shafts operably fixed to one of the pair of spreaders and the other of the pair of concentric shafts fixed to the other of the pair of spreaders.