Sewing machine shuttle construction and sewing machine

Abstract

The problem is to avoid the overcast stitch caused by the under-thread factor. The rotary hook (3) has: a bobbin case (40) that houses the under-thread bobbin; an inner rotary hook (50); and an outer rotary hook (60), with a drop needle hole (51) provided on the upper front surface of the inner rotary hook. On the upper front surface of the inner rotary hook, a recess (52) is formed at a position deviated from the drop needle hole in the rotation direction of the outer rotary hook (for example, a position on the left side relative to the up-and-down movement route of the needle). The front side and the up-and-down opening of the recess (52) are formed with a wall surface on the inner side. A thread guide member (41) for guiding the under-thread from the under-thread bobbin toward the recess is provided on the bobbin case. The under-thread from the under-thread bobbin is guided toward the needle hole of the needle plate via the thread guide member and through the recess. The recess is at a position on the left side relative to the up-and-down movement route of the needle, so the path of the under-thread from the rotary hook toward the needle hole is on the left side of the up-and-down movement route of the needle, and the overcast stitch caused by the under-thread factor can be avoided in terms of structure.

Description

Technical Field

[0001] The present invention relates to a rotary hook structure of a sewing machine that is carefully designed to avoid the formation of wrapped stitches when forming stitches on the sewn material, and to a sewing machine having the rotary hook structure. Background Technology

[0002] Conventional sewing machines are known to include: a sewing mechanism that moves a needle through which an upper thread passes up and down, and a rotary hook holding a lower thread that rotates synchronously with the up-and-down movement of the needle, thereby winding the upper thread around the lower thread to sew a workpiece (fabric); and a feed mechanism that displaces a frame (holding body) holding the workpiece relative to the needle drop position, thereby forming stitches in any direction on the workpiece. In such sewing machines, the feed mechanism controls the movement of the workpiece for each stitch, thus enabling the formation of stitches of various lengths in various directions.

[0003] Regarding the quality of stitches formed using this sewing machine, it is known that there are perfect stitches and wrapped stitches. A perfect stitch is formed when the upper and lower seam threads are wrapped together evenly, while a wrapped stitch is formed when only the upper seam thread is wrapped around the lower seam thread in a spiral pattern. It is known that there are roughly two factors determining whether a stitch is a perfect stitch or a wrapped stitch. One factor is caused by the upper seam thread; that is, when the needle through which the upper seam thread passes pierces the fabric, the upper seam thread, which is pulled back from the front of the needle eye and connected to the fabric, is wrapped around the fabric in a direction corresponding to the direction of fabric movement (stitch formation direction) relative to the needle, either to the left or right, thus forming a perfect stitch or a wrapped stitch. It is known that a wrapped stitch is formed when the upper seam thread is wrapped to the right relative to the needle.

[0004] Furthermore, throughout this instruction manual, "front" ("near front", "front side", "front side", etc.) or "back" ("rear", "back side", "inside", "inner side", etc.) refers to the front or back of the sewing machine as viewed from the main viewpoint, "left" or "right" refers to the left or right of the sewing machine as viewed from the main viewpoint, and "left-turning direction" or "right-turning direction" refers to the direction when viewing the sewing machine from above (i.e., left-turning is counterclockwise, and right-turning is clockwise).

[0005] Another factor is the undersew thread, which depends on the path of the undersew thread (the thread spool) connected to the upper fabric via the needle hole of the needle plate from the rotary hook positioned below the needle plate, and the relationship between the needle's placement position and the stitch, resulting in a perfect stitch or a wrapped stitch. Specifically, a wrapped stitch is formed when the path of the undersew thread is on the right side relative to the needle's vertical movement path (needle placement position), corresponding to the direction of movement of the fabric during stitch formation (stitch formation direction).

[0006] Compared to perfect stitches, wrapped stitches not only have a poorer appearance but also tend to loosen, leading to a decrease in sewing quality. Therefore, various methods have been proposed to avoid wrapped stitches. One example is the following method: during each stitching action, it is determined whether the direction of fabric movement (stitch formation direction) is the direction of perfect stitch formation or wrapped stitch formation. If it is determined to be the direction of wrapped stitch formation, the upper or lower seam thread is displaced relative to the needle drop position by moving the frame or using an operating plate.

[0007] Patent Document 1 discloses an invention to avoid the formation of wrapped stitches due to the upper seam. When it is determined that the moving direction of the frame holding the processed fabric (the stitch forming direction) is the direction for forming wrapped stitches due to the upper seam, the frame is not moved directly to the needle drop position (target position) set for stitch formation. Instead, before the tip of the descending needle reaches the upper surface of the processed fabric, the frame detours to the left of the needle and then reaches the target position. This causes the upper seam connected to the processed fabric to wrap around the needle to the left, thereby avoiding the formation of wrapped stitches due to the upper seam. However, in order to achieve rapid leftward wrapping of the upper seam relative to the needle by detouring the frame during the descent of the needle, the timing of the descent of the needle and the detouring movement of the frame must be precisely synchronized. This presents a problem: if the timing is slightly off, the upper seam cannot wrap around the needle. Therefore, in the technology disclosed in Patent Document 1, it is difficult to reliably avoid the formation of wrapped stitches.

[0008] Patent Document 2 discloses an invention to avoid the formation of a wrapping stitch for the lower seam. In the needle hole formed in the needle plate, a continuous slit is provided on the inner side. When it is determined that the moving direction (stitch formation direction) of the frame holding the processed fabric is the direction for forming a wrapping stitch for the lower seam, the frame is not moved directly to the needle drop position (target position) set for stitch formation. Instead, the frame is moved in a circuitous manner following the shape of the slit before reaching the target position. Specifically, the slit has a front end extending from the left to the right. The frame is moved in a circuitous manner such that the lower seam enters the front end of the slit from the left, causing the lower seam to stop at the front end of the slit. The path of the lower seam stops on the inner side, passing to the left of the needle drop position (i.e., the needle drops to the right and front of the path of the lower seam). Thus, for the path of the lower seam extending upwards and connected to the processed fabric, the needle drops to the right of the lower seam path, thereby intending to avoid the formation of a wrapping stitch for the lower seam. However, the continuous cut on the inside of the needle hole has a front end that extends from the left to the right. This front end and the needle hole will inevitably form a protrusion (the so-called peninsula portion) that extends from the right to the left. Due to the presence of this protrusion, there is a possibility that the upper suture may break.

[0009] As is known, the upper thread loop, caught by the tip of the outer rotary hook, moves between the outer and inner rotary hooks, is lifted by the action of the balance, and rises along the lower thread while winding around it. In the configuration disclosed in Patent Document 2, the upper thread loop rising along the lower thread may hook onto the protrusion (peninsula portion) adjacent to the front end of the cut portion that catches the lower thread. This results in the upper thread breaking. In addition, the lower thread enters the front end of the cut portion and gets caught, so depending on the sewing direction of the next stitch, the lower thread will remain caught by the cut portion, potentially causing problems that differ from the normal lower thread path.

[0010] Patent Document 3 also discloses an invention that avoids the formation of wrapped stitches due to the lower seam. In Patent Document 3, a switching mechanism is provided that selectively switches the lower seam path from the rotary hook to the needle hole of the needle plate to either a left-hand path (biased to the left) or a right-hand path (biased to the right) relative to the vertical movement path (vertical movement trajectory) of the needle, driven by a pressure cylinder. When it is determined that the movement direction (stitch formation direction) of the frame holding the processed fabric is the direction for forming wrapped stitches due to the lower seam, the switching mechanism switches the lower seam path to either the left-hand or right-hand path before the tip of the descending needle reaches the upper surface of the processed fabric, thereby avoiding the formation of wrapped stitches. However, this requires a pressure cylinder-driven switching mechanism, which complicates the construction.

[0011] Patent Document 4 discloses an invention that avoids the formation of wrapped stitches due to upper and lower thread factors. It includes an upper thread control unit (needle bar rotation mechanism) that controls the relationship between the upper thread and the needle; and a lower thread control unit (guide wire mechanism) that controls the relationship between the lower thread and the needle. Each control unit is controlled in accordance with the direction of fabric movement to avoid the formation of wrapped stitches. In Patent Document 4, both the needle bar rotation mechanism (upper thread control unit) and the guide wire mechanism (lower thread control unit) have complex structures, thus complicating the sewing machine's construction. Furthermore, in multi-needle sewing machines with multiple needle bars in a single sewing machine head, this structural complexity becomes an even more serious problem.

[0012] Patent Document 5 discloses a sewing machine capable of rotating the sewing machine head and the rotary hook storage section separately for sewing. As the sewing machine head rotates, the timing of the needle and the rotary hook, as well as the rotation of the sewing machine head and the rotary hook storage section, are synchronized, thereby improving sewing quality. However, this requires a mechanism for rotating the sewing machine head and the rotary hook storage section, and a unit for synchronizing them, resulting in a complex construction. Furthermore, the structure shown in Patent Document 5 is suitable for straight-line sewing in a certain direction, such as dotted stitches. However, in the case of embroidery where the stitch direction is reversed, such as satin stitches, the rotation direction of the sewing machine head and the rotary hook storage section needs to be reversed for each stitch, and the sewing direction also changes, making synchronization very difficult.

[0013] Patent Document 1: Japanese Patent No. 2515400

[0014] Patent Document 2: Japanese Patent Application Publication No. 6-343780

[0015] Patent Document 3: Japanese Patent Application Publication No. 2008-23261

[0016] Patent Document 4: Japanese Patent Application Publication No. 2012-213603

[0017] Patent Document 5: Japanese Patent No. 2540051 Summary of the Invention

[0018] The present invention aims to provide a rotary hook structure for a sewing machine configured to avoid generating wrapped stitches, and to provide a sewing machine having the rotary hook structure.

[0019] According to a first aspect of the present invention, a rotary hook structure for a sewing machine is provided to avoid the formation of wrapped stitches due to the lower sewing thread. The rotary hook structure of the sewing machine according to the present invention is characterized by comprising: a spool housing that rotatably houses a lower sewing thread spool wound with the lower sewing thread; an inner rotary hook that houses the spool housing; and an outer rotary hook that rotates around the inner rotary hook in sync with the up-and-down movement of the sewing needle. A needle drop hole is provided on the upper front surface of the inner rotary hook. A recess is formed on the upper front surface of the inner rotary hook at a position deviating from the needle drop hole in the rotational direction of the outer rotary hook. The recess has openings on its front and upper / lower sides, and a wall surface on its inner side. A thread take-up member is provided in the spool housing for guiding the lower sewing thread led from the lower sewing thread spool toward the recess of the inner rotary hook. The lower sewing thread led from the lower sewing thread spool within the spool housing is drawn upwards via the thread take-up member and through the opening of the recess.

[0020] The rotation direction of the outer rotary hook refers to the direction in which the tip of the rotating outer rotary hook catches (engages) the suture loop inside the hook. Typically, the rotation direction of the outer rotary hook is counter-clockwise. Therefore, the left-right relationship becomes clear; in other words, the movement direction (counter-clockwise) of the tip of the outer rotary hook when catching the suture loop faces left when viewed from the main viewpoint. In this case, the recess of the inner rotary hook is formed at a position closer to the left (closer to the rotation direction of the outer rotary hook) than the vertical movement path of the needle.

[0021] As is known, in a sewing machine, a holder (sewing frame or embroidery frame) holding the workpiece is positioned above the needle plate. This holder is moved in any direction for each stitch, thus enabling stitches to be formed on the workpiece in any direction. Furthermore, as is known, a needle through which the upper thread passes moves up and down, and a rotary hook positioned below the needle plate and housing the lower thread rotates synchronously with the needle's up-and-down movement, causing the upper thread to wrap around the lower thread, thereby sewing the workpiece. The lower thread extending upwards from the rotary hook is formed to pass through the opening (needle eye) of the needle plate and connect with the workpiece. The lower thread extending upwards from the rotary hook and connecting with the workpiece above also moves in tandem with the movement of the holder (workpiece) used to form the stitches. Depending on the direction of movement of the lower thread, the path of the lower thread relative to the up-and-down movement of the needle also changes.

[0022] Depending on the direction of movement of the workpiece during stitch formation (stitch formation direction), there exists a region where the lower sewing thread causes an additional wrapped stitch. The lower sewing thread path extending from the rotary hook to the needle hole of the needle plate reaches the right side of the needle's vertical movement path (vertical movement trajectory), resulting in the aforementioned additional wrapped stitch caused by the lower sewing thread. In view of this, the rotary hook structure of the present invention is configured such that the path of the lower sewing thread extending from the rotary hook to the needle hole of the needle plate does not reach the right side of the needle's vertical movement path (vertical movement trajectory). Specifically, the thread take-up member aligns the lower sewing thread, which is led out by the lower sewing thread spool, toward the recess of the inner rotary hook, and through this recess toward the opening (needle hole) of the needle plate. This recess is formed at a position offset from the needle drop hole toward the rotation direction of the outer rotary hook (i.e., at a position to the left relative to the needle's vertical movement path), thus the path of the lower sewing thread from the rotary hook toward the needle hole is to the left of the needle's vertical movement path. This ensures that the path of the lower sewing thread from the rotary hook toward the needle eye does not reach the right side of the needle's vertical movement path, thus preventing the formation of additional stitches due to the lower sewing thread in terms of construction.

[0023] According to a second aspect of the present invention, a sewing machine is provided that, based on the structure described in the first aspect, has a structure that avoids the generation of wrapped stitches due to the upper sewing thread, thereby preventing the generation of any type of wrapped stitches and enabling the stitches to be formed as perfect stitches throughout the entire range of the sewing direction, that is, enabling the achievement of a completely perfect stitch.

[0024] The second aspect of the present invention relates to a sewing machine comprising: the aforementioned rotary hook structure; and a sewing mechanism that moves the needle through which the upper thread passes vertically, and rotates the outer rotary hook synchronously with the vertical movement of the needle, thereby causing the upper thread to wrap around the lower thread to sew the workpiece. It also comprises: a feed mechanism that displaces a holder holding the workpiece relative to the needle drop position, thereby forming a stitch in any direction on the workpiece; a determination unit that determines whether the direction of forming the next stitch belongs to a predetermined area corresponding to an over-wound stitch; and a detour control unit that, when determined to be within the predetermined area, moves the holder using the feed mechanism, causing the upper thread extending downward from the needle to detour in the direction corresponding to the perfect stitch, and then moves the holder to a target position corresponding to the next stitch. This detour movement of the holder based on the detour control unit avoids the formation of an over-wound stitch due to the upper thread. Attached Figure Description

[0025] Figure 1 It is a diagram that shows the relationship between various stitch formation directions and the quality of the stitches formed according to each direction (perfect stitches and wrapped stitches).

[0026] Figure 2 This is a front view of a sewing machine according to an embodiment of the present invention.

[0027] Figure 3 It is an enlarged representation Figure 2 A front view of a sewing machine head in the illustrated embodiment.

[0028] Figure 4 yes Figure 3 The image shows a side sectional view of the sewing machine head.

[0029] Figure 5 This is an enlarged front view showing an embodiment of a presser foot device for pressing down on sewn materials.

[0030] Figure 6 The figures show a modified example of the guide body of the presser foot device. (a) is an oblique view viewed from the bottom side, (b) is a top view, and (c) is a front view.

[0031] Figure 7The figure shows another variation of the guide body of the presser foot device. (a) is an oblique view viewed from the bottom side, (b) is a top view, and (c) is a front view.

[0032] Figure 8 This is a perspective view showing an example of a pressure foot device with a cover installed at the bottom.

[0033] Figure 9 This is an oblique cross-sectional view showing one embodiment of the needle plate structure.

[0034] Figure 10 It is an enlarged representation Figure 9 The diagram shows the pinhole portion, (a) is a top view, (b) is an oblique view showing the cross-section of line AA, and (c) is an oblique view illustrating the path of the lower suture.

[0035] Figure 11 This is a front view showing an embodiment of the rotary shuttle structure.

[0036] Figure 12 yes Figure 11 A top view of the rotary shuttle structure.

[0037] Figure 13 yes Figure 11 Left and right views of the rotary shuttle structure.

[0038] Figure 14 It means Figure 11 A perspective view of an example of a spool housing contained in a rotary hook construction.

[0039] Figure 15 This is a block diagram representing an example of a sewing machine control system.

[0040] Figure 16 This is an example illustrating the area where the frame is moved in a roundabout manner to avoid the need for additional stitching on the upper seam.

[0041] Figure 17 This is a diagram illustrating the trajectory of the box's meandering movement.

[0042] Figure 18 This is a top sectional view showing the relationship between the upper seam and the guide body of the presser foot device during the roundabout movement of the frame.

[0043] Figure 19 This is a flowchart illustrating an example of a computer program that performs sewing control consisting of perfect stitches according to this embodiment.

[0044] Figure 20The diagram illustrates the structure of the looped stitch that avoids the cause of the under-stitch by means of the rotary hook structure involved in this embodiment. (a) is a front view of the rotary hook structure, and (b) is an enlarged top view showing the relationship between the needle and the under-stitch in the inner rotary hook.

[0045] Figure 21 This is a perspective view explaining the function of the guide body of the presser foot device in the detour movement control of the frame.

[0046] Figure 22 This is a perspective view explaining the function of the guide body of the presser foot device in the detour movement control of the frame.

[0047] Figure 23 To avoid based on Figure 9 and Figure 10 The diagram shows an angled view illustrating the structure of the needle plate with the added stitches.

[0048] Figure 24 This is a diagram showing an example of setting data for box detour control.

[0049] Figure 25 It is an extraction representation Figure 19 The flowchart shows an example of a modification to a computer program. Detailed Implementation

[0050] <The area where the winding stitches are formed>

[0051] First, refer to Figure 1 A typical example of the region forming the direction of the wrapped thread is explained. Figure 1 This is a diagram showing the relationship between various stitch formation directions and the quality of the stitches formed according to those directions (perfect stitches and wrapped stitches). Furthermore, the relationship between stitch formation direction and stitch quality varies depending on the orientation and type of rotary hook. Figure 1 This describes the aforementioned relationship in a fully rotating vertical shuttle (DB type) commonly used in embroidery sewing machines. Furthermore, as is well known, the upper thread passes through the needle eye as follows: the upper thread, extending downwards from its axial direction, enters the needle eye from the front of the needle and passes backwards to connect with the workpiece (fabric). Through the coordinated action of the up-and-down moving needle and the counter-clockwise rotating fully rotating vertical shuttle, as is well known, the upper and lower threads intertwine and form a stitch on the workpiece (fabric).

[0052] The base point C, located at the center of the attached diagram, represents the current needle position (the position of the needle eye on the sewing machine needle plate). Several arrows originating from base point C exemplarily indicate the sewing direction from base point C to the next needle position (i.e., the direction in which the next stitch is formed). As is well known, the sewing direction of each stitch can be arbitrarily set within a 360-degree range, specifically depending on the sewing pattern. Figure 1 In the middle section, for convenience, the direction of arrow P is set to 0 degrees. Rotating counter-clockwise from this point will scale the angles from 0 degrees to less than 360 degrees. Below, when determining the sewing direction (i.e., the direction in which the next stitch is formed) based on the angle, according to... Figure 1 The angle is determined by the scale. In the attached diagram, the directions of arrows P and P' are the left and right directions of the sewing machine. For convenience, the direction of P is referred to as the positive direction of the X-axis (X).

[0053] +), the direction of P' is called the negative direction of the X-axis (X-). The direction of the Y-axis, which is orthogonal to the X-axis at the base point C, is the front-to-back direction of the sewing machine. The direction towards the back (inward) is called the positive direction of the Y-axis (Y+), and the direction towards the front is called the negative direction of the Y-axis (Y-). Furthermore, as is well known, the direction of movement of the holding body (frame) holding the workpiece (processed fabric) is opposite to the direction of the stitch formed according to the movement of the holding body (frame). For example, when forming a stitch in the direction of arrow P (0 degrees), the holding body (frame) moves in the opposite direction of arrow P' (180 degrees).

[0054] exist Figure 1 The diagram depicts a needle pattern that overlaps with several arrows and is surrounded by circles. This needle pattern, along with a needle eye diagram, is a typical example illustrating the relationship between the upper and lower seam lines relative to the needle when forming a stitch in the direction corresponding to the arrow, in order to aid understanding. Furthermore, the diagram depicts the descending needle just before it enters the needle eye. For convenience, an illustration of the workpiece (processed fabric) has been omitted.

[0055] The entire sewing direction can be divided into several regions α to δ based on the quality of the stitches formed corresponding to that sewing direction. Region α is the area to which the sewing direction that results in a perfect stitch belongs, roughly between approximately 270° and 360° (0°) to approximately 85°. As shown in the needle diagram overlapping the arrow in region α, a perfect stitch is formed when the needle is dropped with the upper seam connecting the needle eye and the processing fabric to the left of the needle, accompanying the movement of the retainer (frame). Regions β to δ, excluding region α (shown in white), are areas where wrapping stitches are produced. Region β, marked with a slant line, is the area to which the sewing direction that results in wrapping stitches due to the upper seam is located, roughly between approximately 85° and approximately 180°. As shown in the needle diagram overlapping the arrow in region β, a wrapping stitch is formed when the needle is dropped with the upper seam connecting the needle eye and the processing fabric to the right of the needle, accompanying the movement of the retainer (frame). The dotted area γ represents the sewing direction in which the overlock stitch is created due to the combined effect of the upper and lower seams, and is approximately 180 to 210 degrees. The checkered area δ represents the sewing direction in which the overlock stitch is created due to the lower seam, and is approximately 210 to 270 degrees. As shown in the needle diagram overlapping the arrow in this area δ, the needle is lowered with the lower seam connected to the processed fabric positioned to the right of the needle, accompanying the movement of the retainer (frame). The resulting stitch is an overlock stitch.

[0056] <Basic Structure of a Sewing Machine>

[0057] First, refer to Figures 2-4 The basic structure of an example sewing machine to which the present invention can be applied will be described. Such a basic structure is well known and is not limited to the example shown in the figure; any structure can be applied in the present invention. Figure 2This is a front view of a sewing machine according to an embodiment of the present invention, illustrating an embodiment applicable to a multi-head / multi-needle type embroidery sewing machine. Multiple sewing machine heads H are arranged along the length of the sewing machine frame 1 located above the worktable 2. Below each sewing machine head H, a rotary hook base 4 corresponding to each sewing machine head H is provided. Furthermore, a holding body 5 for holding the sewn material (processed fabric) in an unfolded state is placed on the upper surface of the worktable 2. The holding body 5 is controlled by a feed mechanism (not shown) located below the worktable 2 and moves in the X and Y directions (front-back, left-right directions). The holding body 5 is a structure known as an embroidery frame or a processed fabric holding frame, and will be referred to below as frame 5. An operation panel 6 for operating the sewing machine and setting various parameters is erected on the right side of the sewing machine frame 1. The operation panel 6 is, for example, a touch panel, having a display section for displaying various information and an input section for making various instructions. Furthermore, the feeding mechanism performs its operation in such a way that the frame 5 holding the sewn object is displaced relative to the needle drop position, thereby forming a stitch in any direction on the sewn object. This is well known, so a detailed description is omitted.

[0058] Figure 3 This is an enlarged view of the main front view of the sewing machine head H. Figure 4 This is its side view. The needle bar box 8 is supported on the front surface of the sewing machine arm 7, which is mounted on the front of the sewing machine frame 1, and is able to slide in the left-right direction. Multiple needle bars 9 are supported on the needle bar box 8 so as to be able to move up and down, and the balance 10 corresponding to each needle bar 9 is configured to swing freely. Each needle bar 9 is configured to extend axially in the up-down direction (vertical direction), and a sewing needle 11 is mounted at the lower end of each needle bar 9. Furthermore, in the needle hole 11a of the sewing needle 11 (see reference...) Figure 5 (etc.), the upper suture T passes from near the front to the back (refer to...) Figure 20 (etc.). A sliding shaft 12 is provided through the needle bar box 8. Driven by a motor (not shown), the sliding shaft 12 slides laterally, thereby causing the needle bar box 8 to slide in the left-right direction. Corresponding to the sliding of the needle bar box 8, any one of the plurality of needle bars 9 is selectively located in the operating position, and one needle bar 9 is selected to be operated.

[0059] A main shaft 13 is mounted through the sewing machine arm 7. If the main shaft 13 is rotated using a main shaft motor (not shown), the needle bar drive 15 moves up and down along the base shaft 16 via a cam mechanism (not shown) and connecting rod 14 within the sewing machine arm 7. The needle bar drive 15 has a mechanism that engages with a locking pin 17a of a needle bar holder 17 fixed at a predetermined position on the needle bar 9, switching between a capturing position and a non-capturing position for capturing the needle bar 9. In the capturing position, such as... Figure 4As shown, the needle bar drive body 15 engages with the locking pin 17a of the needle bar holder 17. In the non-capturing position, the engagement between the needle bar drive body 15 and the locking pin 17a of the needle bar holder 17 is released, and the needle bar 9 is held in the upper position (top stop) by the restoring force of the tension spring 18 provided on the upper part of the needle bar 9. In fact, when sewing by moving the needle bar 9 (and the needle 11) up and down, the needle bar drive body 15 is always set in the capturing position. The control that temporarily stops the needle bar 9 (and the needle 11) at the top stop during the sewing operation is known as a jump control. When performing such jump control, the needle bar drive body 15 is temporarily set in the non-capturing position. In order to perform such jump control, a known jump mechanism is provided in the sewing machine head H. That is, the jump mechanism is such that when jump control should be performed during the sewing operation, the needle 11 is held in the upper position and not lowered. As an example, the jumping mechanism consists of a jumping motor (not shown), a drive component (not shown), and the tension spring 18, which are installed on the sewing machine arm 7. The drive component causes the needle bar drive body 15 to rotate around the base axis 16 by a predetermined angle according to the drive of the jumping motor, thereby setting the needle bar drive body 15 in a non-capturing position.

[0060] When the needle bar 9, selected as the operating position, is captured by the needle bar drive body 15, it moves up and down in response to the lifting and lowering motion of the needle bar drive body 15. During the up and down movement of the needle bar 9 in the operating position, the sewing needle 11 mounted at its front end is inserted into the needle hole 19a of the needle plate 19, performing the sewing action as is known. On the other hand, if the jump mechanism operates in response to the drive of the jump motor (not shown), the needle bar drive body 15 is set to the non-capturing position, the needle bar 9 is not captured by the needle bar drive body 15, and is formed into a jump state as described above and held at the upper stop point.

[0061] In the needle bar box 8, lifting rods 20 are respectively configured to move up and down behind each needle bar 9. Similar to the needle bars 9, the lifting rods 20 are configured to extend axially in the vertical direction, and each has a presser foot device 21 at its lower end. The presser foot device 21 is used to press the sewn workpiece from above as the needle 11 descends, and is configured to include a pressing member 22 and a guide body 23, which will be described in detail later. The pressing member 22 is installed at the lower end of the lifting rod 20, and the guide body 23 is provided at the lower end of the pressing member 22. One lifting rod 20 corresponding to the needle bar 9 selected for the operating position is driven by a presser motor 24 provided on the sewing machine arm. A linkage mechanism 25 is connected to the presser motor 24. If the presser motor 24 is driven to rotate reciprocally, the presser drive body 26, which is vertically mounted on the sewing machine arm 7, is raised and lowered via the linkage mechanism 25. The fabric pressing drive 26 has a structure that engages with the locking pin 27a of the lifting rod seat 27 fixed at a predetermined position of each lifting rod 20. The locking pin 27a of one of the multiple lifting rods 20 in the needle bar box 8 corresponding to the needle bar 9 selected for the operating position engages with the fabric pressing drive 26. The lifting rod 20, along with the presser foot device 21 (pressing member 22 and guide body 23), moves axially up and down due to the lifting movement of the fabric pressing drive 26. When the needle bar 9 is raised using the jump mechanism, the fabric pressing motor 24 stops, and the presser foot device 21 (pressing member 22 and guide body 23) stops at a predetermined upper position (top stop).

[0062] The combination of the sewing machine head H and its corresponding rotary hook 3 is equivalent to the following sewing mechanism: the needle 11 through which the upper thread passes moves up and down, and the rotary hook 3, which holds the lower thread, rotates synchronously with the up and down movement of the needle 11, thereby causing the upper thread to wrap around the lower thread to sew the workpiece.

[0063] <Construction of the presser foot device>

[0064] Figure 5 This is an enlarged front view showing one embodiment of the presser foot device 21. A mounting member 28 is provided at the lower end of the lifting rod 20, and the pressing member 22 of the presser foot device 21 is detachably mounted to this mounting member 28 via screws. The lower end of the pressing member 22 extends directly below the needle bar 9 and has a through hole 22a for inserting the sewing needle 11. Therefore, when the needle bar 9 descends, the pressing member 22 also descends, forming a state where it presses down on the workpiece from above. At this time, the further descending sewing needle 11 passes through the through hole 22a and pierces the workpiece to sew. This structure is the same as that of a fabric pressing device as is known. A further feature of this embodiment is that a downwardly protruding guide 23 is provided at the lower end of the pressing member 22. Furthermore, the constituent parts 22, 23, etc., of the presser foot device 21 can also be made of materials such as metal.

[0065] The guide body 23 is formed into an approximately cylindrical shape, having a hollow portion (an opening in the vertical direction) communicating with the through hole 22a of the pressing member 22. The needle 11, passing through the through hole 22a, can pass through the hollow portion and vertically through the guide body 23. The guide body 23 is not a complete cylinder; in frontal view, from the left front of the inserted needle 11 to a position opposite the left side, it has an open portion (cut) 29 extending to the lower end of the guide body 23 (see also...). Figure 8 The opening (cut) 29 is naturally connected to the hollow portion of the guide body 23. A portion of the upper sewing thread (the part connected to the sewn object side) that passes through the hollow portion and through the needle hole 11a of the needle 11 can pass through the opening 29 and extend outward from the guide body 23 according to the direction of movement of the frame 5. Viewed from above, the rotation direction of the rotary hook 3 (counterclockwise) is, in other words, to the left. Therefore, it can be said that the opening 29, which is generally formed on the left side when viewed from the front, is configured to allow the upper sewing thread to pass in the direction of rotation of the rotary hook 3. Thus, a structure is formed in which the upper sewing thread can extend outward from the guide body 23 via the opening 29. Therefore, as described later, the upper sewing thread can be wound around the needle 11 in a leftward winding manner (i.e., in the direction of rotation of the rotary hook 3) according to a wide range of movement directions of the frame 5.

[0066] In the guide body 23, the leading and trailing edges of the opening 29, which is generally formed on the left side, correspond to the leading edge 23a and trailing edge 23b of the raw material wall portion of the guide body 23. That is, the opening 29 is bounded by its leading and trailing edges, and when the upper sewing thread, corresponding to the movement of the frame 5, is led outward from its opening and then detours to move in another direction, its movement is restricted by the leading edge 23a or trailing edge 23b of the raw material wall portion of the guide body 23. The restricting action of the leading edge 23a plays an important role in avoiding the generation of additional stitches due to the upper sewing thread. Therefore, in this embodiment, the raw material wall portion of the guide body 23 that approaches the front surface from the leading edge (i.e., leading edge 23a) of the opening 29 is called the restricting portion 23a. The movement of the upper sewing thread that the restricting portion, i.e., the leading edge 23a, restricts in the direction away from the leading edge of the opening 29, which is generally formed on the left side, is a movement to the right, in other words, a movement in the opposite direction to the rotation direction (counterclockwise) of the rotary hook 3. Therefore, it can be said that the limiting part 23a of the guide body 23 is set to restrict the movement of the upper sewing thread in the opposite direction to the rotation direction of the rotary hook 3.

[0067] As described above, the opening 29 is configured to extend to the lower end of the guide 23. Therefore, the limiting portion 23a, which divides the leading edge of the opening 29, is configured to restrict the movement of the upper sewing thread passing through the opening 29 in the opposite direction to the rotational direction of the rotary hook 3, until it reaches the lower end of the guide 23. Therefore, with the upper sewing thread limited by the limiting portion 23a, corresponding to the descent of the needle 11, the upper sewing thread moves along the limiting portion 23a to the lower end of the guide 23, then passes downward through the opening 29, releasing the limitation of the limiting portion 23a. If the limitation of the limiting portion 23a is released, the upper sewing thread is wound around the needle 11 in a leftward winding manner (i.e., in the rotational direction of the rotary hook 3). As an example, the limiting portion 23a of the guide 23 is provided within a suitable range from the leading edge of the opening 29 to a position near the front surface. As described in detail later, the limiting part 23a formed in the guide 23 prevents the upper sewing thread from reaching the right side of the needle 11 (by wrapping it around the needle 11 to the left) when the needle 11 is inserted into the workpiece, in order to avoid the formation of a wrapping stitch. Figure 5 In the diagram, symbol V represents the vertical movement trajectory (vertical movement path) of the needle 11. Furthermore, to prevent the upper sewing thread from reaching the right side of the needle 11 when it penetrates the workpiece, the limiting portion (leading edge) 23a provided on the guide body 23, or at least its lower end (the part that abuts against the workpiece), is located further to the left than the vertical movement trajectory V of the needle 11. That is, the limiting portion 23a is positioned offset from the vertical movement path of the needle 11, closer to the rotation direction (left side) of the rotary hook 3, thus limiting the movement of the upper sewing thread.

[0068] exist Figure 5 (or Figure 8 In the embodiment shown, the leading edge of the opening 29, i.e., the limiting portion (leading edge portion) 23a formed on the guide 23, has a shape (recessed portion) that is cut obliquely from top to lower left. This oblique shape (recessed portion) makes the opening in the upper or middle part of the opening 29 slightly wider forward than the lower opening. Therefore, when the needle 11 and the pressing member 22 descend, if the portion of the upper suture that extends from the opening 29 and is limited by the limiting portion 23a becomes loose, the wider opening absorbs this loosening, maintaining the upper suture based on the limiting portion 23a as much as possible. This prevents the upper suture from slipping off the limiting portion 23a before the needle 11 penetrates the workpiece. However, this oblique shape is not necessary; the leading edge of the opening 29, i.e., the limiting portion (leading edge portion) 23a formed on the guide 23, can also be formed vertically.

[0069] Furthermore, the shape of the guide body 23 is not limited to the approximately cylindrical shape described above, and can be any shape. Figure 6The figures shown are modified examples of the guide body 23. (a) is an oblique view viewed from the bottom side, (b) is a top view, and (c) is a front view. Figure 6 The guide body 23-1 shown is composed of two sidewalls connected at an appropriate angle (e.g., approximately 90 degrees). The space other than these sidewalls serves as a space for the needle 11 to pass through (corresponding to the hollow portion) and an opening 29 for the upper suture thread to pass through in the direction of rotation of the rotary hook 3. The sidewalls on the front surface of the guide body 23-1 function as a restrictive portion 23a.

[0070] Figure 7 The following is a diagram showing another variation of the guide body 23: (a) is an oblique view viewed from the bottom side, (b) is a top view, and (c) is a front view. Figure 7 The guide body 23-2 shown is composed of three sidewalls connected in sequence at an appropriate angle (e.g., approximately 90 degrees). The space other than these sidewalls serves as a space for the needle 11 to pass through (corresponding to the hollow portion) and an opening 29 for the upper suture thread to pass through in the direction of rotation of the rotary hook 3. The sidewalls on the front surface of the guide body 23-2 function as a restrictive portion 23a.

[0071] also, Figures 5-7 The guide body 23 shown has a wall portion, the side edge of which on the front surface side functions as a restrictor 23a. However, it is not limited to this; it may not have a wall portion and instead form the restrictor 23a in the form of a thinner pin-shaped or wire-shaped column member. For example, it may be formed by arranging two thinner column members and creating a space as an opening 29 between them, so that one (front surface side) column member functions as the restrictor 23a. In this case, an arc-shaped connecting leg connecting the lower ends of the two thinner column members may be provided on the opposite side of the opening 29. As a variation, one or more other thinner column members may be provided in the middle of the arc-shaped connecting leg. As another variation, the guide body 23 may also be composed of only one thinner column member that functions as the restrictor 23a.

[0072] Figure 8 This figure shows another variation of the presser foot device 21, in which a cover 30 covering the guide body 23 is provided on the lower side of the pressing member 22. The structure of the presser foot device 21, apart from the elements related to the cover 30, is similar to... Figure 5The structure shown is the same. The bottom side of the cover 30 is a smooth, curved convex surface (bowl-shaped), and a through hole with a large diameter is provided to allow the guide body 23 to be slowly retracted. The upper inner side is formed into a recess suitable for the pressing member 22. The cover 30 is installed from the lower side of the guide body 23 and fastened with screws 31, thereby assembling and fixing the cover 30 to the pressing member 22, thus covering the side of the guide body 23. The guide body 23 is loosely retracted inside the cover 30 with gaps, so that the function of the guide body 23 is not impaired. As a result, the lower periphery of the guide body 23 is surrounded by the convex curved surface (bowl-shaped) bottom surface of the cover 30, so even if the vertical stroke of the presser foot device 21 is reduced to prevent the sewn work from shaking, the guide body 23 can be prevented from getting caught on the stitches of the moving work.

[0073] <Needle Plate Construction>

[0074] In this embodiment, a new structure is provided in relation to the needle hole 19a of the needle plate 19 to avoid the generation of extra stitches caused by the lower sewing thread. Figure 9 This is a perspective view showing one embodiment of this new needle plate construction. Figure 10 It is an enlarged representation Figure 9 A partial view of the pinhole 19a is shown in Figure 1. (a) is a top view, (b) is an oblique view showing a section along line AA in (a), and (c) is an oblique view illustrating the path of the lower suture D. Figure 10 As illustrated by the dotted lines in (a), the currently known needle hole 19a is roughly a simple circular hole. The vertical movement path of the needle 11 ( Figure 5 The V in the diagram passes roughly through the center of the circle.

[0075] Regarding the needle plate structure involved in this embodiment, a guide hole 31 and a groove 32 are provided in relation to the needle hole 19a on the needle plate 19. The guide hole 31, which is formed by penetrating the needle plate 19, is located near the front surface of the sewing machine and communicates with the needle hole 19a, and is closer to the rotation direction of the rotary hook 3 than the up-and-down movement path of the needle 11. Figure 10 (a) is offset near the left side. Furthermore, the needle plate 19 has a direction opposite to the rotational direction of the guide hole 31 towards the rotary hook 3 on the near-front side of the needle hole 19a. Figure 10 (a) extends a groove 32 on the right side. The upper part of this groove 32 and the portion communicating with the guide hole 31 are open, and the rest of the portion forms the bottom surface 32a and the side wall 32b. Figure 10(b)). As is well known, during the sewing operation, the lower sewing thread D extending from the rotary hook 3 extends upward through the needle hole 19a, forming a stitch on the workpiece. In this embodiment, it is configured such that the lower sewing thread D extending from the rotary hook 3 passes not only through the needle hole 19a but also through the guide hole 31 connected thereto. Moreover, it is configured such that when the lower sewing thread D is in the state of passing through the guide hole 31, depending on the direction of movement of the frame 5, as... Figure 10 As shown in (c), a portion of the lower suture D extending upward from the guide hole 31 can be guided towards the front side of the needle hole 19a via the groove 32. The groove 32 has a bottom surface 32a, so a portion of the lower suture D on the lower side remains in the guide hole 31, while a portion of the lower suture D on the upper side bends and is guided towards the upper space of the groove 32.

[0076] The guide hole 31 is offset from the vertical movement path of the needle 11, closer to the rotation direction of the rotary hook 3 (near the left side). The groove 32 extends from the guide hole 31 in the opposite direction (right side) of the rotation direction of the rotary hook 3, near the front side of the needle hole 19a. Therefore, when the frame 5 is moved approximately to the left by the detour movement control of the frame 5 (described later), the lower sewing thread D is guided by the guide hole 31. Then, as the frame 5 moves towards the needle drop position (target position) and approximately to the right, the lower sewing thread D is guided approximately to the right from the guide hole 31 along the groove 32. At this time, the two sides of the groove 32 are sidewalls 32b, so the lower sewing thread D is stopped on the inner sidewalls 32b and does not move further inward than the vertical movement path of the needle 11, but remains closer to the front than the vertical movement path of the needle 11. In this way, the path of the lower sewing thread D extending from the rotary hook 3 to the needle hole 19a of the needle plate 19 will not reach the inner side of the up-and-down movement path of the needle 11, but will remain near the front side, thereby avoiding the generation of wrapped stitches (especially double wrapped stitches). In addition, the groove 32 has a bottom surface 32a, so the loop of the upper sewing thread, which is moving upward along the lower sewing thread D through the needle hole 19a while shrinking, will not get caught in the groove 32, so there is no need to worry about the upper sewing thread breaking. Furthermore, the lower sewing thread D is only stopped at the side wall 32b of the groove 32, so if the lower sewing thread D is pulled up as the upper sewing thread rises, the lower sewing thread D can easily disengage from the groove 32 and return to the normal path (i.e., the path through the needle hole 19a), so it will not adversely affect the formation of the path of the lower sewing thread D during the next stitch formation.

[0077] like Figure 10As shown in the top view of (a), as an example, at the junction of the guide hole 31 and the needle hole 19a, the inner wall surface 31a of the guide hole 31 slopes from the inside towards the forward direction (i.e., the left front) closer to the rotation direction of the rotary hook 3. That is, the wall surface 31a slopes from the inside towards the left front, so that the innermost side is closest to the vertical movement path of the needle 11 and the frontmost side moves away from the vertical movement path of the needle 11 to the leftmost side. This slope of the wall surface 31a at the junction helps the lower seam D to smoothly move from the needle hole 19a to the guide hole 31 along the path of the lower seam D when the frame 5 moves in a detour, allowing the lower seam D to move smoothly towards the guide hole 31 along this slope. However, it is not limited to this, and the shape of the junction of the guide hole 31 and the needle hole 19a can be designed arbitrarily.

[0078] <Rotary Structure>

[0079] In this embodiment, a new structure is provided in relation to the rotary hook 3 to avoid the formation of additional stitches due to the lower seam. Figure 11 This is a front view showing an embodiment of this new rotary shuttle structure. Figure 12 This is its top view. Figure 13 (a) is its left view. Figure 13 (b) is its right view. As is known, the rotary hook 3 is positioned below the needle plate 19. As an example, the rotary hook 3 is a vertical full-rotation rotary hook (DB type). The rotary hook 3 has: a spool housing 40 that rotatably houses a lower spool (not shown) wound with the lower suture thread; an inner rotary hook 50 that houses the spool housing 40; and an outer rotary hook 60 that rotates around the inner rotary hook 50 in sync with the up-and-down movement of the needle 11. The inner rotary hook 50 is fixed to the rotary hook base 4 via a rotary hook support 70, as is known, and the spool housing 40 is fixed inside the inner rotary hook 50. The outer rotary hook 60 is fixed to a lower shaft (not shown) that rotates in sync with the up-and-down movement of the needle 11, and rotates together with the lower shaft. Regarding the vertical full-rotation rotary hook (DB type), the rotation direction R of the outer rotary hook 60 is counterclockwise. A needle drop hole 51 is provided on the upper front surface of the inner rotary shuttle 50 to avoid interference with the sewing needle 11.

[0080] On the upper front surface of the inner rotary hook 50, a recess 52 is formed at a position offset from the needle hole 51 in the rotational direction R of the outer rotary hook 60. This recess 52 has openings at the front and bottom, and an inner wall 52a is formed therein. This inner wall 52a is positioned at a near-limit position where it does not interfere with the movement trajectory of the tip 61 of the outer rotary hook 60. By positioning the inner wall 52a of the recess 52 at this near-limit position, the lower sewing path connecting the recess 52 to the workpiece (the position of the lower sewing from the recess 52 towards the needle hole 19a) can be positioned as far as possible behind (behind) the needle drop (up and down movement trajectory). Therefore, using the rotary hook structure of this embodiment, the area of ​​the wrapped stitch that avoids the need for a lower sewing stitch can be expanded as much as possible. The left and right walls of the recess 52 are the upstream side wall 52b located on the upstream side of the rotation direction R of the outer rotary shuttle 60, and the downstream side wall 52c located on its downstream side.

[0081] A thread-taking member 41 is provided at a predetermined location near the upper part of the spool housing 40 (preferably below the recess 52). This thread-taking member 41 guides the lower thread, which is led from the lower thread spool, toward the recess 52 of the inner rotary hook 50. As described in detail later, the lower thread, led from the lower thread spool inside the spool housing 40, is drawn upwards via the thread-taking member 41 and through the opening of the recess 52 of the inner rotary hook 50. Corresponding to the rotation of the outer rotary hook 60, the lower thread through the recess 52 winds around the upper thread loop, as is known, and extends upwards from the needle eye 19a as the needle 11 rises, forming a stitch. Thus, the recess 52 provided in the inner rotary hook 50 functions in a way that forms the path of the lower thread.

[0082] According to this rotary hook structure, the path of the lower thread connecting the rotary hook 3 to the workpiece above through the needle hole 19a of the needle plate 19 passes through the recess 52 provided on the upper front surface of the inner rotary hook 50 and reaches the left side relative to the vertical movement path (needle drop position) of the needle 11. That is, the lower thread led out from the lower thread spool is oriented by the thread take-up member 41 toward the recess 52 of the inner rotary hook 50, and passes through the recess 52 toward the needle hole 19a of the needle plate 19. The recess 52 is formed at a position offset from the needle drop hole 51 in the rotational direction R of the outer rotary hook 60 (i.e., the position on the left side relative to the vertical movement path of the needle 11), and its inner wall surface 52a is formed at a roughly limit position that does not interfere with the movement trajectory of the tip 61 of the outer rotary hook 60. Therefore, the path of the lower thread from the rotary hook 3 toward the needle hole 19a becomes the left inner side of the vertical movement path of the needle 11. Therefore, the path of the lower stitch from the rotary hook 3 toward the needle eye 19a can be prevented from reaching the right side of the up-and-down movement path of the needle 11, thereby reducing the generation of wrapped stitches.

[0083] Regarding this point, refer to Figure 1To further explain. In region δ, which corresponds to the sewing direction where the lower thread will generate a wrapping stitch, frame 5 moves to the right-inward direction, 180 degrees opposite to it. Therefore, with the current rotary hook configured to supply the lower thread from below the vertical movement path of the needle, the needle is dropped when the lower thread path is to the right of the vertical movement path of the needle due to the pulling of the workpiece, thus generating a wrapping stitch. In contrast, in this embodiment, when frame 5 moves to the right-inward direction for sewing in region δ, the lower thread from rotary hook 3 toward needle hole 19a abuts against the inner wall 52a of recess 52, and the movement of the lower thread to the right is limited by the upstream side wall 52b. Therefore, the lower thread extending from rotary hook 3 passes to the left of the vertical movement path of needle 11 toward needle hole 19a, thus suppressing the wrapping stitch by dropping the needle to the right of the lower thread.

[0084] For example, in belonging to Figure 1 In the sewing direction of region δ, when the frame 5 moves in a direction of approximately 70 degrees, the lower seam path is reliably located to the left of the needle drop (the vertical movement path of the needle 11). Therefore, even assuming that the arrangement of the inner wall 52a of the recess 52 is shallower than the aforementioned approximate limit position, the generation of wrapping stitches can be avoided. Conversely, for example, when the frame 5 moves in a direction of approximately 40 degrees, if the arrangement of the inner wall 52a of the recess 52 is shallower than the aforementioned approximate limit position, the lower seam path will not be located to the left of the needle drop (the vertical movement path of the needle 11), but will reach the right side via the front side, thus wrapping stitches cannot be avoided. However, as described above, by setting the arrangement of the inner wall 52a of the recess 52 to the aforementioned approximate limit position, even when the frame 5 moves in a direction of approximately 40 degrees, for example, the lower seam path can be located to the left of the needle drop (the vertical movement path of the needle 11), thus avoiding wrapping stitches. In this way, the more the inner wall surface 52a of the recess 52 is positioned on the inside, the more the area that can be expanded by utilizing the rotary hook structure involved in this embodiment to avoid the need for additional stitches due to the lower seam. In addition, by setting the inner wall surface 52a to the above-mentioned approximate limit position, the area that does not require frame detour control is maximized.

[0085] Furthermore, a structure can be provided on the downstream sidewall 52c of the recess 52 to stop the lower seam thread during cutting. For example... Figure 12As shown, the downstream sidewall 52c protrudes further forward than the upstream sidewall 52b, forming a protrusion 52d at its front end. Above the rotary hook 3, a thread-cutting device (not shown), as is known, is provided. When this device performs its cutting action, a portion of the lower sewing thread extending from the rotary hook 3 towards the needle hole 19a is captured and guided to the left to a cutting position, where it is cut. When the lower sewing thread moves to the left for the cutting action, it abuts against the downstream sidewall 52c and can move appropriately along the downstream sidewall 52c in the front-back direction. In this case, if the leading edge of the downstream sidewall 52c is on the same plane as the sidewall, the lower sewing thread is prone to detach from the leading edge of the downstream sidewall 52c. Consequently, the lower sewing thread travels a short distance from the rotary hook 3 to the thread-cutting device. If it is cut in this state, the remaining length of the cut lower sewing thread will be shortened, potentially causing obstruction in the next operation. To prevent this adverse situation, a protrusion 52d is provided at the front end of the downstream sidewall 52c, slightly protruding from its surface. Thus, during the thread-cutting operation, the lower thread, which abuts against the downstream sidewall 52c, is stopped by the protrusion 52d as it moves forward, preventing the lower thread from detaching from the leading edge of the downstream sidewall 52c. This design ensures that the remaining length of the lower thread after cutting is sufficiently guaranteed, preventing obstruction during subsequent operations.

[0086] Next, a further improvement example of the inner rotary hook 50 and the outer rotary hook 60 will be described. As is known, the outer rotary hook 60 has a tip 61 on its outer periphery, which is used to catch the loop of the upper thread drawn from the needle eye 11a of the sewing needle 11. In addition, a thread-separating spring (i.e., the upper spring portion) 62 is fixed to the outer peripheral surface of the outer rotary hook 60 by screws. The front end 62a of the thread-separating spring 62 is formed in a claw shape to guide the upper thread caught by the tip 61. In addition, as Figure 13 As shown in (b), the front edge (i.e., the front side edge) 62b of the dividing spring 62 is formed to be located further inward (rearward) than the inner wall surface 52a of the recess 52 of the inner rotary hook 50. In other words, the front edge 62b of the dividing spring 62 is formed not to extend further forward than the front side edge (the front side edge of the movement track) of the tip 61 of the outer rotary hook 60.

[0087] Regarding the currently known thread-separating springs, in order to push the upper thread loop captured by the rotation of the outer shuttle forward, they are shaped with a portion (fin) that protrudes forward at its leading edge, tending to move backward in the direction of rotation. Thus, if the leading edge of the thread-separating spring protrudes, the lower thread from the shuttle toward the needle eye is also pushed forward, thereby creating slack in the lower thread.

[0088] In contrast, in this embodiment, the spring 62 is configured such that, in order to prevent the thread-separating spring 62 from contacting the lower seam guided by the recess 52, the aforementioned protruding portion (fin) is not formed on its front end edge 62b, thereby preventing the lower seam from slackening. Thus, in this embodiment, the thread-separating spring 62 does not push the thread loop forward, and is therefore more broadly referred to as the upper spring portion.

[0089] Instead of omitting the protruding portion (fin) at the front end edge 62b of the dividing spring (upper spring portion) 62, the structure of the inner rotary hook 50 is improved in this embodiment as described below. Figure 11 and Figure 13 As shown in (a), on the outer periphery of the front surface of the inner rotary hook 50, within a range of approximately 1 / 4 arc angle (i.e., 90 degrees) in the downstream direction of rotation from the recess 52, more specifically within a range of less than 1 / 4 arc angle (i.e., 90 degrees), particularly within a range of approximately 80 degrees in the example shown, a forward-protruding ridge 53 is formed. Specifically, the ridge 53 has a mountain-shaped cross-section, a guide surface 53a that slopes forward as it rotates upstream, and is formed such that its ridge height decreases as it rotates downstream. The ridge 53 functions to push the upper stitching loop, which is caught by the tip 61 of the outer rotary hook 60, forward. As the outer rotary hook 60 rotates, the upper stitching loop is pushed forward while moving upward (from rear to front) from below the ridge 53, and passes around the inner rotary hook 50 while moving along the front surface of the spool housing 40. In this way, the raised portion 53 of the inner rotary shuttle 50 can function as a substitute for the fins of the currently known splitting spring.

[0090] In addition, such as Figure 11 and Figure 12 As shown by the double-dotted line, the protrusion 71 of the rotary hook support 70, which is fixed to the rotary hook base 4, can engage with the recess 52 of the inner rotary hook 50. In the engaged state, the inner rotary hook 50 is fixed to the rotary hook base 4, preventing the inner rotary hook 50 from rotating together with the outer rotary hook 60. A suitable opening space is formed between the inner wall surface 52a of the recess 52 and the front end of the protrusion 71 of the rotary hook support 70, through which the lower seam thread guided to the recess 52 passes and faces the needle hole 19a.

[0091] Furthermore, referring to Figure 14 An example of the spool housing 40 will be described. Furthermore, in Figure 14 The illustration of the lower seam thread spool housed within the spool housing 40 is omitted. (See diagram for reference.) Figure 14As shown in (a), the main body 42 of the spool housing 40 has an opening 42a on its upper front surface to prevent interference with the needle 11 during insertion. A lead-out hole 42b is formed on the main body (outer peripheral side) of the spool housing 42 for leading out the lower sewing thread from the internally housed lower sewing thread spool, and a sewing thread adjusting spring 43 is installed to apply tension to the lower sewing thread. Furthermore, a guide groove 42c is formed above the lead-out hole 42b to restrict the passage position of the lower sewing thread. Additionally, the upper part of the main body of the spool housing 42 also has an opening that communicates with the opening 42a.

[0092] The thread take-up member 41 is disposed on the upper part of the front surface of the spool housing 40, specifically, on the lower side of the opening 42a, near the left side. Preferably, the thread take-up member 41 is made of spring material to apply tension to the lower thread leading from the lower thread spool toward the opening of the recess 52 of the inner rotary hook 50. Therefore, the thread take-up member 41 will also be referred to below as the thread take-up spring. The thread take-up spring (thread take-up member) 41 has an annular or curved loop portion 41a through which the lower thread leading from the lower thread spool passes (hooks), and through which the lower thread toward the opening of the recess 52 of the inner rotary hook 50. The tension of the thread take-up spring 41 appropriately guides the lower thread toward the needle hole 19a so that it passes through the recess 52 (i.e., restricts the path of the lower thread to pass through the recess 52), and absorbs slack in the lower thread. The take-up spring 41 extends substantially horizontally on the front surface of the spool housing 40, with one end (right end) of the ring portion 41a fixed to the spool housing 40 on the opposite side, and the ring portion 41a being a free end. This ring portion 41a is located approximately directly below the recess 52 of the inner rotary hook 50, and can swing in the up-down and left-right directions as the lower thread moves through this location due to the spring's restoring force. In one embodiment, the length from the fixed end (right end) of the take-up spring 41 to the end (left end) of the ring portion 41a is relatively long, as shown in the figure. This allows for a relatively larger swing range (stroke range) of the take-up spring 41, and also enables it to absorb a greater degree of slack in the lower thread. Thus, by constructing the take-up member 41 from spring material, it not only reliably guides the lower thread towards the recess 52 of the inner rotary hook 50, but also prevents slack in the lower thread under various conditions by applying tension to it.

[0093] The lower sewing thread, drawn from the lead-out hole 42b of the spool housing 40, abuts against the sewing thread adjusting spring 43, passes through the guide groove 42c, through the ring portion 41a of the take-up spring 41 and reverses upward, passes through the recess 52 of the inner rotary hook 50, and exits into the needle hole 19a. Furthermore, not limited to this, the lower sewing thread drawn from the lead-out hole 42b of the spool housing 40 may, after passing the sewing thread adjusting spring 43, pass through the ring portion 41a of the take-up spring 41 instead of the guide groove 42c.

[0094] As an optional component, such as Figure 14 As shown in (b), a guide member 44 may also be provided in front of the thread take-up spring (thread take-up component) 41 in the spool housing 40. The guide member 44 is freely mounted to the upper left of the front surface of the spool housing body 42 by means of screws. The guide member 44 has a guide surface 44a protruding forward from its mounting position, which is formed in such a way that it is substantially connected to the front surface of the spool housing 40 (forming a substantially consistent surface). By providing the guide member 44 in this way, the upper thread loop, which moves to the front surface of the spool housing 40 and moves upward as the rotary hook 3 rotates, can smoothly move along the front surface of the spool housing.

[0095] Furthermore, the guide surface 44a of the guide member 44 is provided with an opening 44b extending in the front-rear direction. This opening 44b is used to insert the front end of a picker (not shown) as known. A picker as known refers to a device that, when the upper thread is cut based on a thread-cutting device (not shown), maintains the upper thread on the needle side to ensure a specified amount of residual thread and prevent the upper thread from passing through the needle eye. A picker as known has a pair of left and right front ends. During the thread-cutting action, these two front ends are inserted into the opening 42a of the spool housing 40, and the upper thread passing through the rotary hook 3 is held at the two front ends, thereby ensuring a specified amount of residual upper thread and preventing the thread from falling out of the needle eye. Such a picker can also be used in this embodiment. However, regarding the picker (not shown) used in this embodiment, in order to prevent interference with the thread-taking spring 41, the length of one front end (the left front end) of the picker must be slightly shorter than that of the current picker. The guide surface 44a and opening 44b of the guide member 44 provide a structure suitable for this particular pickup. That is, when the pickup is installed, the shorter end (the left end) of the pickup enters the opening 44b of the guide surface 44a of the guide member 44, but does not abut against the thread take-up spring 41. Thus, as the upper thread loop moves upward along the guide surface 44a of the guide member 44, which protrudes forward of the thread take-up spring 41, the upper thread loop reliably engages with both ends of the pickup (i.e., also with the shorter end), thereby ensuring a predetermined amount of residual thread and preventing the thread from slipping out of the needle eye 11a of the needle 11. Furthermore, this guide member 44 is not essential; for example, it is not required in sewing machines of the type without a pickup.

[0096] <Box Circumvention Control>

[0097] In this embodiment, to avoid additional stitching caused by the upper seam, as mentioned above, a guide body 23 is provided in the presser foot device 21, and the detour control of the frame 5 is performed based on this guide body. This detour control of the frame is executed by the electrical / electronic control system. Figure 15This is a block diagram illustrating an example of a control system for a sewing machine (i.e., a control device for the sewing machine). As is well known, this control system includes: a CPU (Central Processing Unit) 101 for controlling various processes and drives of the sewing machine; a RAM (Random Access Memory) 102 serving as the working area of ​​the CPU 101; and a storage device (ROM = Read-Only Memory and / or a read-write memory such as flash memory or hard disk) 103 for non-volatilely storing embroidery data (sewing data) of one or more pre-programmed patterns and associated program control data (program control data), as well as various processing programs and data. Furthermore, the control system includes: a driver 104 for a spindle motor that rotates the sewing machine spindle 13; drivers 105 and 106 for an X-axis motor and a Y-axis motor that move the frame 5 in the X and Y directions, respectively; a driver 107 for a jump-start motor that jumps the needle bar 9; and a driver 108 for a presser foot device 21 that raises and lowers the presser foot motor 24, each driver being connected to the corresponding motor. In addition, the control system includes a user input / output interface 109, including the operation panel 6. As described above, the operation panel 6 is a touch panel that combines image display and user input operation reception, displaying various setting / control screens. Users can perform various operations / settings by touching the operation images displayed on the touch panel. Furthermore, it may have a communication interface (not shown) for communication with external devices and / or internal or external communication networks.

[0098] As is well known, under the control of CPU 101, sewing data for any pattern selected by the user is read from storage device 103. Based on the sewing data for each stitch, drivers 104-108, etc., are controlled to perform sewing actions and sequentially form stitches. Based on this sewing data, it can be determined whether the direction of forming the next stitch belongs to a predetermined area for forming a wrapping stitch (e.g., ...). Figure 1 The area shown is β to δ. This determination can be made by a program executed by CPU 101. That is, CPU 101 and the program function as a determination unit, which determines whether the direction of forming the next stitch belongs to the specified area for forming the wrapping stitch based on the sewing data read from storage device 103.

[0099] In this embodiment, to avoid the formation of additional stitches due to the upper seam, if it is determined that the direction of forming the next stitch belongs to the designated area for forming additional stitches, then when moving frame 5 to the target position corresponding to the next stitch, detour control is performed to make frame 5 move in a roundabout manner. This detour control can be performed using a program executed by CPU 101. That is, CPU 101 and the program function as a control unit (i.e., a detour control unit), which performs the jump control using the jump mechanism (107, etc.) and activates the feed mechanism (105, 106, etc.) when the determination unit determines that the direction of forming the next stitch belongs to the designated area, thereby making frame 5 move in a roundabout manner. Here, the meandering movement of frame 5 refers to, after moving frame 5 in the direction in which the upper seam extending downward from the needle 11 protrudes from the opening 29 of the guide 23 of the presser foot device 21 with the needle 11 in the upward position, moving frame 5 towards the target position corresponding to the next stitch, so that the upper seam extending from the opening 29 abuts against the limiting part 23a of the guide 23. The movement of frame 5 that causes the upper seam extending from the opening 29 to abut against the limiting part 23a of the guide 23 is merely a meandering movement of the upper seam extending from the opening 29 via the limiting part 23a. That is, the detour movement refers to the following movement, that is, instead of moving the frame 5 immediately to the target position corresponding to the next stitch, the frame 5 is temporarily moved in the direction that causes the upper stitch to extend from the opening 29 of the guide 23 while the needle 11 is in the upward position. Then, the upper stitch extending from the opening 29 is detoured in such a way that it abuts (via) the restriction 23a, and finally reaches the target position corresponding to the next stitch.

[0100] like Figure 1 As a typical example, the sewing direction that causes the wrapping stitch due to the upper seam is located in regions β and γ. A portion of region β around 90 degrees (i.e., the region where the sewing direction is on the inside of the sewing machine) is an area where the wrapping stitch can be avoided by moving frame 5 with less detour; for convenience, this is referred to as region S1. For reference, in... Figure 16 An example of region S1 is shown below. Figure 16 In, with Figure 1 Similarly, the base point C, located at the center of the attached diagram, represents the current needle drop position (the position of the needle hole 19a of the needle plate 19). Based on angles ranging from 0 degrees to less than 360 degrees, marked counterclockwise, the sewing direction from base point C to the next needle drop point (i.e., the direction forming the next stitch) is determined. The movement direction of frame 5, corresponding to the area S1 with a sewing direction of approximately 90 degrees, is the area approximately 270 degrees opposite (180 degrees to the opposite side). For reference, in Figure 16The figure shows an example of the target position of the frame 5 corresponding to the stitch in the sewing direction belonging to the first region S1. As can be understood from the figure, when the frame 5 moves in a detour, it is closer to the target position T1 corresponding to the next stitch than to the position where the frame 5 temporarily moves in the direction (left front side) causing the upper seam to extend from the opening 29 of the guide 23. Therefore, the target position T1 can be reached by moving the frame 5 in a detour with a smaller amount of detour. The range of the first region S1 is shown in the figure as a range of angles a to b, for example, a range of approximately 85 degrees to less than 112 degrees, but as will be described later, this range can be appropriately varied.

[0101] The remaining region S2 within the sewing direction where the upper seam requires additional stitching is the region where additional stitching is avoided by moving frame 5 in a more circuitous manner. For convenience, this region is referred to as the second region. The second region S2 contains... Figure 1 The remaining portion of region β and the entire region γ are shown. The direction of movement of box 5 corresponding to this second region S2 is the opposite of it (180 degrees to the opposite side), for reference. Figure 16 The figure shows an example of the target position for the movement of frame 5 corresponding to the stitch in the sewing direction belonging to the second region S2, illustrated by T2. As can be understood from the accompanying drawings, when frame 5 moves in a detour, the target position T2 corresponding to the next stitch may be farther and closer to the inside than the position where frame 5 temporarily moves in the direction (left front side) causing the upper seam to extend from the opening 29 of guide 23. Therefore, to reach the target position T2, frame 5 needs to be moved in a detour with a large amount of detour. The range of the second region S2 is shown in the figure as a range from angle b to c, for example, a range of approximately 112 degrees to 210 degrees, but as described later, this range can be appropriately varied. Furthermore, the regions with different detour amounts are not limited to the two regions (S1, S2) mentioned above, but can also be three or more regions. Furthermore, in Figure 16 In the diagram, S0 represents the region where box 5 does not move in a roundabout way. This region S0 contains... Figure 1 The regions α and δ are shown.

[0102] In one embodiment, the control unit may perform the jump control once, twice, or more times during the detour movement. In one embodiment, if the direction of forming the next trace belongs to the first region S1, the control unit performs the jump control once during the detour movement; if the direction of forming the next trace belongs to the second region S2, the control unit performs the jump control twice during the detour movement.

[0103] Figure 17 This is a diagram illustrating several trajectories of the detour movement of block 5 executed through the block detour control of the control unit. Figure 17 In, with Figure 16 Similarly, C represents the (current) needle position (base point) at the start of the detour, and T1 and T2 represent the needle position (target position) at the end of the detour. Relatedly, Figure 18 This is a top cross-sectional view showing the relationship between the upper seam T and the guide body 23 of the presser foot device 21 when the frame 5 moves in a detour. The horizontal cross-section shows the guide body 23, the needle 11, and the portion of the upper seam T entering its needle hole 11a. However, it should be noted that, as mentioned earlier, in the jump state, the needle 11 is located at a higher position than the guide body 23. Therefore, the cross-section of the guide body 23 and the cross-section of the needle 11 (and the cross-section of the portion of the upper seam T entering its needle hole 11a) do not represent cross-sections at the same height.

[0104] Figure 17 (a) This indicates the trajectory of the detour when the direction of forming the next stitch belongs to the first region S1. In this example, a jump control (one stitch amount) is performed during the detour. The needle bar 9 (needle 11) rising from the base point C is set to the jump state by the jump mechanism and held above. Additionally, the presser foot motor 24 stops, and the presser foot device 21 stops at a predetermined upper position. Simultaneously, the control box 5 moves in a direction that causes the upper seam T extending downward from the needle 11 to protrude from the opening 29 of the guide body 23. Figure 17 In (a), A1 represents the movement of box 5 at this time. The endpoint (i.e., the midpoint of the detour) m1 of the movement of box 5 A1 can be set to an appropriate XY coordinate value. If efficient (compact) detour movement is desired, the endpoint (i.e., the midpoint) m1 of A1 can be set in a direction that makes the movement of box 5 A1 in the left diagonally forward direction as shown in the figure. However, it is not limited to this and can be set appropriately within the scope of the spirit of this embodiment. Figure 18 (a) indicates the state in which the upper stitch T extends from the open portion 29 of the guide body 23 to the left and forward as the frame 5 moves by A1. If the frame 5 reaches the midpoint m1, the jump control of 1 stitch amount ends.

[0105] Next, move box 5 from its midpoint m1 to the target position T1 corresponding to the next line. Figure 17 In (a), A2 represents the movement of frame 5 at this time. As shown in the figure, the movement of frame 5 A2 is in the right-sloping-forward direction. During the movement A2, the upper seam T extending from the open part 29 of the guide body 23 abuts against the limiting part 23a of the guide body 23. The movement of the upper seam T to the right is limited by the limiting part 23a. Figure 18(b) indicates the state where the upper sewing thread T abuts against the limiting part 23a as the frame 5 moves A2 at this time. In this state, the upper sewing thread T extending from the needle hole 11a of the needle 11 is located to the left of the needle 11. During the movement of the frame 5 from the midpoint m1 toward the target position T1, the needle bar 9 (needle 11) and the presser foot device 21 descend. Of course, appropriate timing adjustments are made to ensure that the frame 5 reaches the target position T1 and completes the detour before the descending needle 11 and presser foot device 21 contact the upper surface of the workpiece.

[0106] Figure 17 (b) indicates the trajectory of this detour when the direction of forming the next stitch belongs to the second region S2. In this example, two jump controls (two stitch amounts) are performed during this detour. The needle bar 9 (needle 11) rising from the base point C is set to the jump state by the jump mechanism and held above. Additionally, the presser foot motor 24 stops, and the presser foot device 21 stops at the predetermined upper position (top stop). Simultaneously, the control box 5 moves in a direction that causes the upper seam T extending downward from the needle 11 to protrude from the opening 29 of the guide body 23. As previously described, in Figure 17 (b) also uses A1 to represent the movement of frame 5 at this time. As mentioned before, the endpoint (i.e., the first intermediate point) m1 of the movement of frame 5 A1 can be set to an appropriate XY coordinate value. As mentioned before, if efficient (compact) detour movement is considered, the endpoint (i.e., the first intermediate point) m1 of A1 can be set in such a way that the movement of frame 5 A1 is in the direction of left diagonal forward as shown in the figure. As mentioned before, the state in which the upper seam T extends from the opening 29 of the guide body 23 in the direction of left diagonal forward as frame 5 moves A1 is as follows. Figure 18 As shown in (a), when box 5 reaches the first intermediate point m1, the first jump control (1 line trace) ends, but in order to maintain the jump state, the second jump control (1 line trace) continues.

[0107] Next, while maintaining the jump state, move box 5 from the first midpoint m1 towards the second midpoint m2. Figure 17 In (b), A2 represents the movement of frame 5 at this time. As shown in the figure, the movement of frame 5 A2 is in the direction of right diagonal forward. During this movement A2, the upper seam T extending from the open portion 29 of the guide body 23 abuts against the limiting portion 23a of the guide body 23, and the movement of the upper seam T to the right is limited by the limiting portion 23a. If we represent the state when the upper seam T abuts against the limiting portion 23a during the movement A2, then it is similar to... Figure 18(b) Same. In this state, the upper sewing thread T extending from the needle hole 11a of the needle 11 is located to the left of the needle 11. The endpoint of the movement A2 of the frame 5 (i.e., the second intermediate point m2) can be set to appropriate XY coordinate values. Considering reliable contact (locking) with the target position T2 and the limiting part 23a, the endpoint of A2 (i.e., the second intermediate point m2) can be set in a manner that positions the movement A2 of the frame 5 in an appropriate right-south-forward direction as shown in the figure. If the frame 5 reaches the second intermediate point m2, the second jump control ends. Furthermore, upon reaching the endpoint of movement A2 (the second intermediate point m2), the upper sewing thread T is formed to be wrapped around the limiting part 23a to the left.

[0108] Next, move box 5 from the second midpoint m2 toward the target position T2 corresponding to the next stitch. Figure 17 In (b), A3 represents the movement of frame 5 at this time. The movement of frame 5, A3, is shown in the rightward inward direction. With this movement A3, the upper seam T further wraps around the restrictor 23a to the left and towards the rightward inward direction. However, regarding the point that the upper seam T extending from the needle eye 11a of the needle 11 is located to the left of the needle 11, ... Figure 18 (b) is the same. During the movement of frame 5 from the second midpoint m2 toward the target position T2, the needle bar 9 (sewing needle 11) and presser foot device 21 descend. As previously described, appropriate timing adjustments are made so that frame 5 reaches the target position T2 and completes the detour before the descending sewing needle 11 and presser foot device 21 contact the upper surface of the sewn work.

[0109] In the above Figure 17 In the frame detour control shown in (a) and (b), frame 5 detours are performed intermittently. For example, the sewing data (frame movement data) of each stitch and the jump control code can be pre-programmed to perform a detour based on one jump control, using the combination of the sewing data of the first stitch (frame movement data towards the intermediate point m1) and the jump control code, and the sewing data of the next stitch (frame movement data towards the target position T1). Alternatively, a detour based on two jump controls can be performed, using the combination of the sewing data of the first stitch (frame movement data towards the first intermediate point m1) and the jump control code, the combination of the sewing data of the next stitch (frame movement data towards the second intermediate point m1) and the jump control code, and the sewing data of the last stitch (frame movement data towards the target position T2). Furthermore, the number of jump controls in the frame detour control is not limited to one or two as described above; it can be greater than or equal to three times, or it can be only one time.

[0110] The detour movement in box 5 is not limited to the example of intermittent movement as described above; it can also be performed continuously. Figure 17 (c) represents an example of continuous detour movement of box 5. Similar to (b), the target position is T2. This example represents continuous detour movement along the same trajectory A1, A2, A3 as in (b). For example, when the jump control codes are continuous, a parameter can be set to make box 5 move continuously. Based on this parameter, box 5 will continuously move detour until the target position T2 while the needle bar 9 is in a jump state.

[0111] <Preventing upper seam loosening>

[0112] In one embodiment, during the meandering movement of the control box 5, measures can be taken to prevent the upper seam T from slackening. Therefore, as Figure 3 As shown, a suture slack prevention part 200 is arranged at the lower part of the needle bar box 8. The suture slack prevention part 200 is positioned above the suture locking device 400 as is known, and its base plate 201 is fixed at both ends to brackets mounted on the left and right sides of the needle bar box 8 by screws. At the position of the base plate 201 corresponding to each needle bar 9, a pressing piece 203 is held in place by a screw 202 with a spring embedded in the shaft. The suture T hanging from the balance 10 (in Figure 3(Illustration omitted) The upper seam T passes between the base plate 201 and the pressing piece 203. By adjusting the screw 202's screw-in depth, the spring force is changed, thereby applying a small tension to the upper seam T passing between the base plate 201 and the pressing piece 203 using contact resistance. The upper seam T, through the upper seam slack prevention part 200, passes through the upper seam locking device 400 and the needle hole 11a of the corresponding needle 11. The tension applied to the upper seam T by the screw 202 of the upper seam slack prevention part 200 and the pressing piece 203 is sufficient to prevent the upper seam T, which is caught (wound) to the guide body 23, from falling downwards due to slack during the tortuous movement control of the frame 5. By utilizing the upper suture slack prevention part 200, even if the upper suture T portion above the upper suture slack prevention part 200 slackens when the balance 10 moves up and down during the jump of the needle bar 9, the contact resistance of the upper suture slack prevention part 200 can prevent the upper suture T portion below it from slackening. This prevents the upper suture T, which is caught (wound) to the guide body 23, from falling downwards due to slackening during the tortuous movement control of the frame 5. Furthermore, the structure of the upper suture slack prevention part 200 is not limited to the structure shown in the figure; any structure that prevents the upper suture T from slackening can be used. Alternatively, the upper suture locking device 400, as is known, can be used instead of the special upper suture slack prevention part 200. Since the upper suture slack prevention part 200 always applies tension to the upper suture T, it can be assumed that even a small contact resistance will affect the take-up of the thread. As a variation, the upper seam slack prevention part 200 can also be made movable, like the upper seam locking device 400, and tension can be applied only when the frame 5 is being controlled in a roundabout manner.

[0113] Achieving perfect stitch control

[0114] The sewing machine shown in the above embodiment can avoid the formation of wrapped stitches due to the upper and lower seam threads, and achieve sewing that makes the stitches in the entire range of the sewing direction perfectly stitched. Figure 19 This is a flowchart illustrating an example of a computer program that performs sewing control consisting of perfectly stitched seams according to this embodiment, the program being stored, for example, in... Figure 15 The CPU 101 executes the commands within the storage device 103 shown.

[0115] Figure 19The program shown begins when sewing action starts on a pattern (embroidery pattern or other sewing pattern) composed of multiple stitches selected by the user. In step St1, the value of the stitch counter n, which represents the stitch formation order, is set to an initial value of 1. In step St2, stitch movement data Pn (XY movement data in box 5) is obtained for forming the stitches in the order (nth stitch) specified by the current value of the stitch counter n. In step St3, the needle direction (i.e., the direction of forming the next stitch) of the stitch movement data Pn is calculated using the current needle drop position as a base point C. In step St4, it is determined whether the calculated needle direction (the direction of forming the next stitch) belongs to... Figure 16 The area S0 shown is the area where no box detour control is performed. If it is YES, proceed to step St5; if it is NO, proceed to step St8.

[0116] In step St5, frame 5 is moved to the target position corresponding to the stitch movement data Pn, and needle bar 9 is lowered to perform a single stitch. During the sewing action in step St5, frame 5 does not undergo any roundabout movement. As mentioned earlier, in Figure 16 The region S0 shown contains Figure 1 The regions α and δ are shown. If the calculated needle direction (the direction that forms the next stitch) belongs to region α, a perfect stitch can be formed by performing only the normal sewing action. On the other hand, if the calculated needle direction (the direction that forms the next stitch) belongs to region δ, the aforementioned unique rotary hook structure can avoid the formation of wrapped stitches due to the lower seam thread, and a perfect stitch can be formed. Details are as follows.

[0117] <Avoidance of Wrapped Lines in Region δ>

[0118] Figure 20 The figures illustrate the structure of the looped stitch that avoids the need for under-stitching through the rotary hook construction according to this embodiment. (a) is a front view of the rotary hook construction, and (b) is an enlarged top view showing the relationship between the needle and the under-stitch in the inner rotary hook 50. Furthermore, Figure 20 The rotary shuttle 3 shown is the same as the reference. Figures 11-14 The same applies to the rotary hook 3. When the direction of forming the next stitch belongs to region δ, the frame 5 moves towards the target position corresponding to the next stitch and in the right-inward direction. The lower seam D from the rotary hook 3 towards the needle hole 19a is pulled in the right-inward direction as the frame 5 moves, as... Figure 20As shown in (a) and (b), the lower sewing thread D abuts against the inner wall 52a of the recess 52 of the inner rotary hook 50, and the movement of the lower sewing thread D to the right is restricted by the upstream side wall 52b of the recess 52. Thus, the lower sewing thread D extending from the rotary hook 3 passes through the left inner side of the vertical movement path of the needle 11 towards the needle eye 19a, connecting with the workpiece W above. Therefore, when the vertically moving needle 11 is below the needle plate 19, the lower sewing thread D is always located on the left inner side of the needle 11 and will not reach its right side. This construction method avoids the formation of wrapped stitches in region δ due to the lower sewing thread, and the wrapping of the upper sewing thread T and the lower sewing thread D in the rotary hook 3 forms a perfect stitch.

[0119] Furthermore, when the needle 11 passes through the workpiece (processed fabric) W, it causes the workpiece to sway up and down, resulting in slack in the lower thread D, which may cause the slack lower thread D to move to the right of the needle tip 11. However, in this embodiment, by making the thread take-up member 41 have a spring action, even if the lower thread D slacks due to the swaying of the workpiece W, the spring action of the thread take-up member (thread take-up spring) 41, located approximately directly below the recess 52 of the inner rotary hook 50, quickly absorbs the slack in the lower thread D, thus maintaining the lower thread D in a taut state and preventing the lower thread D from moving to the right of the needle tip 11. Moreover, as mentioned above, the front edge 62b of the upper spring portion (thread separating spring) 62 of the outer rotary hook 60 is located further back than the inner sidewall 52a of the recess 52 of the inner rotary hook 50, so the front edge 62b will not come into contact with the lower thread D and push the lower thread D forward. Therefore, the lower seam thread D will not slack due to the upper spring portion (separating spring) 62 of the outer rotary hook 60. In this way, a foolproof countermeasure is taken to eliminate the possibility of additional stitches caused by the slack of the lower seam thread D.

[0120] Return to Figure 19 In step St8, it is determined whether the needle movement direction (the direction that forms the next stitch) calculated in step St3 belongs to... Figure 16 The first region S1 (a portion of region β) is shown. If the answer is YES, proceed to step St9. In step St9, the process is performed by... Figure 17 (a) The smaller, meandering movement trajectory shown in the diagram constitutes the first region S1, which uses frame meandering movement control. If the determination in step St8 is NO, it means that the needle direction calculated in step St3 (the direction that forms the next stitch) belongs to... Figure 16 The second region S2 shown (including the remainder of region β and region γ). In this case, proceed to step St10, and execute the... Figure 17 (b) shows the frame-based detour movement control used in the second region S2, which is formed by the larger detour movement trajectory.

[0121] <Avoidance of Wrapped Stitches in Area S1>

[0122] Regarding the frame detour movement control (1-time jump control) used in the first region S1 during step St9, as follows: Figure 17 As shown in (a), with the needle bar 9 in a jumping state, the frame 5 is moved to the midpoint m1, and then the frame 5 is moved to the target position T1, so that the needle 11 falls onto the workpiece W. Details are as follows, please refer to the following: Figure 21 As explained. Figure 21 This is a perspective view explaining the function of the guide body 23 of the presser foot device 21 in the detour movement control of frame 5.

[0123] With the needle bar 9 jumping up and the needle 11 held above, the frame 5 is moved towards the center point m1, so that the frame 5 is as follows: Figure 17 (a) Moved as shown in A1, as in Figure 18 (a) shows the state in which the upper seam T extends from the open portion 29 of the guide body 23 of the presser foot device 21 in a direction diagonally forward to the left. Figure 21 (a) The current state is shown in a perspective view. Next, move box 5 from the midpoint m1 to the target position T1, so that box 5 is as shown... Figure 17 (a) moves as shown by trajectory A2, as shown. Figure 18 (b) shows the state in which the upper suture T is restricted by the limiting part 23a of the guide body 23. At the same time, the needle 11 and presser foot device 21 are lowered by releasing the jumping state of the needle bar 9.

[0124] Figure 21 (b) indicates the state before the descending needle 11 enters the through hole 22a of the pressing member 22 of the presser foot device 21. As shown in the figure, the upper thread T, which is connected to the workpiece W from the rear of the needle hole 11a of the needle 11, is hooked onto the limiting part 23a of the guide body 23 (more specifically, the cut part of the limiting part 23a), which restricts the movement of the needle 11 to the right side of its up-and-down movement path and keeps it on the left side of the needle 11.

[0125] Figure 21 (c) indicates the state before the needle 11 descends further into the guide 23 of the presser foot device 22 and is about to pierce the workpiece W. The needle 11, descending within the guide 23, extends from behind its needle hole 11a, is restricted by the limiting part 23a, and passes through the right side of the portion of the upper seam T connected to the workpiece W. If the guide 23 of the presser foot device 21 reaches its lower stop, the descent of the presser foot device 21 stops, and only the needle 11 descends further thereafter.

[0126] Figure 21(d) indicates the state where the tip of the needle 11, which has descended further, passes through the guide 23 and pierces the workpiece W. The portion of the upper suture T connected to the workpiece W from behind the needle hole 11a of the needle 11 is restricted from moving to the right by the limiting part 23a of the guide 23, thereby maintaining it in the left position of the needle 11 and descending along the limiting part 23a as the needle 11 descends.

[0127] Figure 21 (e) indicates that the needle 11 descends further, causing the portion of the upper seam T connecting to the workpiece W from behind the needle hole 11a to reach a position lower than the lower end of the guide 23. In this state, the portion of the upper seam T connecting to the workpiece W from behind the needle hole 11a detaches from the restraint portion 23a, forming a state where it is wound in a leftward direction relative to the needle 11.

[0128] As the needle 11 descends further, passing through the workpiece W and the needle hole 19a of the needle plate 19, with a portion of the needle hole 11a positioned below the needle plate 19, a portion of the upper seam T extending from behind the needle hole 11a and connecting to the workpiece W above extends upward along the left side of the needle 11, passing through the needle hole 19a and reaching the workpiece W. Thus, with the needle 11 descending to the rotary hook 3, the path of the upper seam T from behind the needle hole 11a to the workpiece W (needle hole 19a) above remains on the left side of the needle 11. With the needle 11 lowered into the rotary hook 3 as described above, the upper suture T, extending upward from behind the needle hole 11a, is caught by the tip 61 of the outer rotary hook 60, forming (drawing out) an upper suture loop by moving together with the tip 61. Through a combination of the rotation of the rotary hook 3, the rise of the needle 11, and the movement of the balance 10, the loop of the upper suture T wraps around the lower suture D to form a stitch. The upper suture T, extending from behind the needle hole 11a, enters the rotary hook 3 in a state located to the left of the needle 11 (wound to the left relative to the needle 11), thus forming a perfect stitch. As described above, the generation of over-wound stitches in the first region S1 (a part of region β) can be avoided.

[0129] <Avoidance of Wrapped Stitches in Area S2>

[0130] Regarding the frame detour movement control (2-step jump control) used in the second region S2 during step St10, as follows: Figure 17 As shown in (b), while the needle bar 9 jumps up by one stitch, the frame 5 is moved to the first midpoint m1. Next, while the needle bar 9 jumps up by another one stitch, the frame 5 is moved to the second midpoint m2. Finally, the frame 5 is moved to the target position T2, causing the needle 11 to fall onto the workpiece W. For details, please refer to [reference needed]. Figure 21 (a) and Figure 22As explained below.

[0131] With the needle bar 9 jumping up by one stitch length while keeping the needle 11 above, move the frame 5 towards the first midpoint m1, so that the frame 5 is as follows: Figure 17 (b) Moved as shown in A1, as in Figure 18 As shown in (a), the upper seam T, extending downward from the rear of the needle eye 11a of the upper needle 11, extends diagonally forward and to the left from the opening 29 of the guide body 23 of the presser foot device 21. This state is as follows: Figure 21 (a) is shown in the oblique view.

[0132] Next, the needle bar 9 is continuously raised (as a state of raising one stitch), causing frame 5 to move from the first midpoint m1 to the second midpoint m2, thus frame 5 as shown... Figure 17 (b) The trajectory A2 shows a general movement to the right. If box 5 reaches the second midpoint m2, the jump control ends. Upon reaching the end point of movement A2 (the second midpoint m2), the upper seam T becomes wrapped to the left relative to the limiting part 23a of the guide 23. The state at this time is as follows Figure 22 As shown in the oblique view, the upper seam T, which descends from the needle 11 and connects to the workpiece W, wraps more deeply to the left around the limiting portion 23a of the guide body 23. Thus, the frame's meandering movement, based on two-stage jump control, reliably engages the upper seam T with the limiting portion 23a, thereby preventing mis-engaging.

[0133] Finally, move box 5 from the second midpoint m2 to the target position T2, so that box 5 is as shown. Figure 17 (b) The movement follows the trajectory A3 shown. With this movement A3, the upper thread T wraps further to the left around the restrictor 23a and towards the right-side inward direction. Thus, the upper thread T, connected to the workpiece W from behind the needle hole 11a of the needle 11, wraps more deeply to the left and engages more firmly with the restrictor 23a of the guide 23, restricting the needle 11 from moving to the right of its vertical path and keeping it on the left side of the needle 11. The jump control ends, and therefore, during the movement of the frame 5 from the second midpoint m2 towards the target position T2, the needle bar 9 (needle 11) and the presser foot device 21 descend.

[0134] The state of the upper seam T during the process of the further descending needle 11 passing through the workpiece W and the needle eye 19a to reach the rotary hook 3 is similar to that described above. Figure 21The states described in (c) to (e) are the same. That is, the portion of the upper suture T extending from the rear of the needle hole 11a of the needle 11 enters the rotary hook 3 while remaining on the left side of the needle 11 (wound to the left relative to the needle 11), thereby forming a stitch that avoids the formation of a wrapped stitch due to the upper suture. In particular, in the portion of region β in the second region S2, as described above, a perfect stitch is formed by avoiding the formation of a wrapped stitch due to the upper suture. Regarding region γ in the second region S2, since both wrapped stitches based on the upper suture and wrapped stitches based on the lower suture exist, it is not sufficient to only avoid the formation of wrapped stitches based on the upper suture; it is also necessary to avoid the formation of wrapped stitches based on the lower suture. Specifically, this is because even if the lower suture is wound to the left relative to the needle 11 by frame detour control, a double wrapped stitch will be generated if the lower suture is located behind (rear) the vertical movement path of the needle 11. As previously mentioned, the unique needle plate construction associated with the needle hole 19a of the needle plate 19 avoids the need for additional stitches in region γ due to the lower suture material. Details are as follows.

[0135] <Avoidance of underlock stitches in region γ>

[0136] As mentioned above Figure 9 and Figure 10 As described above, a guide hole 31 and a groove 32 are formed in relation to the needle plate 19 and the needle hole 19a. Figure 23 This is an oblique view explaining the structure of the overlock stitch that avoids the need for underlock stitching by utilizing the construction of the needle plate 19 with such a guide hole 31 and groove 32. Figure 23 For ease of explanation, the frame 5 and the workpiece W located between the presser foot device 21 and the needle plate 19 are omitted. Similarly, the lower side of the upper seam T and the upper side of the lower seam D are also omitted. Furthermore, for convenience, the distance between the guide body 23 of the presser foot device 21 and the needle plate 19 (needle hole 19a) is depicted as fixed, but in reality, this distance changes as the presser foot device 21 moves up and down.

[0137] Figure 23 (a) Roughly representing the state of frame 5 when it moves to the first midpoint m1 (in the direction of left-southeast) during the frame detour movement control (2-jump control) for the second region S2 in step St10. In this state, the upper seam T extending downward from the rear of the needle hole 11a of the upper needle 11, as previously described, extends in the direction of left-southeast from the opening 29 of the guide body 23 of the presser foot device 21. The lower seam D extending upward from the rotary hook 3 and connected to the workpiece W passes through the needle hole 19a corresponding to the needle drop position before frame 5 moves, but is guided from the needle hole 19a to the guide hole 31 as frame 5 moves toward the first midpoint m1 (in the direction of left-southeast).

[0138] Figure 23 (b) indicates the state when frame 5 has moved approximately to the second midpoint m2 (approximately to the right) during the frame meandering movement control (two-jump control) in the second region S2 performed in step St10. In this state, the upper suture T, extending downward from the needle hole 11a of the upper needle 11, is engaged with the limiting part 23a of the guide body 23 as previously described. The movement of the needle 11 to the right of the vertical movement path is restricted, and it wraps around the limiting part 23a to the left. As frame 5 moves from the first midpoint m1 to the second midpoint m2 (approximately to the right), the lower suture D bends from the guide hole 31 and enters the upper space of the groove 32, and is guided approximately to the right along the groove 32.

[0139] Figure 23 (c) indicates the state when frame 5 has moved approximately to the target position T2 (approximately to the right and inward) during the frame detour movement control (2-jump control) in the second region S2 performed in step St10. In this state, the upper suture T, extending downward from the needle hole 11a of the upper needle 11, further wraps to the left around the limiting portion 23a of the guide 23, as previously described. The lower suture D, as frame 5 moves from the second midpoint m2 towards the target position T2 (approximately to the right and inward), is engaged with the inner side wall 32b of the groove 32 (i.e., near the needle hole 19a). Figure 10 (b)) will not shift to the inner side of the up-and-down movement path of the needle 11, but will remain near the front side of the up-and-down movement path of the needle 11. This means that the path of the lower suture D drawn upward from the rotary hook 3 to the needle plate 19 is maintained near the front side of the up-and-down movement path of the needle 11.

[0140] With frame 5 at target position T2, the needle 11 descends further and then ascends. During this process, corresponding to the rotation of the rotary hook 3, the loop of the upper thread T wraps around the lower thread D as described above to form a stitch. At this stage, the upper thread T, extending from behind the needle hole 11a, enters the rotary hook 3 on the left side of the needle 11 (relative to the left of the needle 11), and its path from the lower thread spool to the lower thread D on the needle plate 19 is maintained near the front of the needle 11's vertical movement path, as described above. Therefore, sewing that avoids both the upper and lower thread wrapping (i.e., a double wrapping stitch) is achieved.

[0141] Furthermore, as the frame 5 moves in a roundabout manner, the lower thread D is also drawn out, but the slack of the drawn-out lower thread D is quickly absorbed by the spring action of the aforementioned thread take-up member 41. That is, in this embodiment, the thread take-up member 41 has a spring action, so that even if the lower thread D is drawn out as the frame 5 moves in a roundabout manner, the slack of the lower thread D is quickly absorbed by the spring action of the thread take-up member (thread take-up spring) 41 provided on the rotary hook 3, and the lower thread D can be kept taut. Therefore, it is not easy for the lower thread D to slack out and disengage from the locking part (groove 32) of the needle plate 19. That is, in this embodiment, the thread take-up member (thread take-up spring) 41 also functions as a tension application unit provided below the needle plate 19 to apply tension to the lower thread that is led upward from the rotary hook 3 toward the needle hole 19a or guide hole 31 of the needle plate 19.

[0142] As is well known, the loop of the upper seam T, captured by the tip 61 of the outer rotary hook 60, passes through the inner rotary hook 50 and through the balance 10. Figure 4 As the upper sewing thread T shrinks, it is lifted along the lower sewing thread D. In this embodiment, the groove 32 is formed with a bottom surface 32a, so the loop of the upper sewing thread T, which travels upward along with the lower sewing thread D through the needle hole 19a while shrinking, will not get caught in the groove 32, thus forming a structure that does not cause the upper sewing thread to break. Furthermore, when the needle is dropped at the target position T2, the lower sewing thread D only gets caught on the inner sidewall 32b of the groove 32 of the needle plate 19. Figure 10 (b) Therefore, if the lower suture D is lifted as the upper suture T rises, the lower suture D can easily detach from the groove 32 and return to the normal path (i.e. the path through the needle hole 19a), so it will not adversely affect the path formation of the lower suture D when the next stitch is formed.

[0143] As mentioned above, in Figure 19 In this process, steps St5, St9, and St10 are performed based on the needle direction of the stitch movement data Pn (i.e., the direction in which the next stitch is formed), thereby enabling sewing to achieve a perfectly stitched result that avoids the formation of (all types) wrapping stitches caused by upper and lower seam factors.

[0144] right Figure 19The remaining steps are explained below. After the processing in steps St5, St9, and St10, proceed to step St6, where the stitch counter n is incremented by 1. In the following step St7, it is determined whether the incremented value n is greater than the "total number of stitches" of the pattern currently being sewn. If it is NO, return to step St2, and repeat the processing after step St2 as described above for the incremented value n (i.e., the "next stitch"). If the sewing of the pattern currently being sewn is completed, the result in step St7 is YES, and the process ends. Figure 19 The program.

[0145] <Setting the frame detour control data>

[0146] In one embodiment, it can be configured such that the user can arbitrarily set / change various data associated with the box detour control (i.e., the conditions used for detour control). Figure 24 This indicates that the operation panel 6 ( Figure 2 This section describes a screen display example for setting / changing various data (conditions for bypass control) associated with frame bypass control. The operation panel 6 has a touch-operable display screen on which the required images and data are displayed according to various operating modes. In the setting mode, for example, a parameter setting screen 110 as shown in the illustration is displayed on the operation panel 6. As an example, the parameter setting screen 110 displays setting items numbered 21 to 30 for frame bypass control along with each current setting value. As another example, instead of displaying multiple setting items (numbered 21 to 30) simultaneously on the parameter setting screen 110, at least one setting item may be displayed, and the displayed setting items may be switched sequentially by scrolling or the like.

[0147] If you touch and select the desired setting item from numbers 21 to 30 displayed on the parameter setting screen 110, the current setting value associated with the selected setting item is displayed on the display unit 111. By operating the setting value switching key 112, you can increase or decrease the current setting value associated with the selected setting item, and this change is also displayed on the display unit 111. After changing the setting value, if you press the confirm key 113, the changed setting value becomes effective.

[0148] Item 21, "Using Full Perfect Stitch (Apfs)," relates to a setting unit that determines whether to enable or disable the execution box detour movement control. For example, you can toggle whether the execution box detour movement control is enabled by setting Yes / No. In the illustration, it is shown as set to "Yes." Alternatively, this setting can be "ON / OFF" instead of "Yes / No."

[0149] To enable / disable the detour movement control of actual control box 5 according to this setting, simply... Figure 19 Part of the process was changed to Figure 25 That's fine. Specifically, insert step St11 between steps St3 and St4. In step St11, determine whether "Use Full Perfect Stitch (Apfs)" is set to YES (i.e., whether the detour movement of execution box 5 is enabled). If step St11 is YES, proceed to step St4 and, as previously described, execute the detour movement control of box 5. If step St11 is NO, skip step St4 and proceed to step St5 without executing the detour movement control of box 5.

[0150] By enabling or disabling the detour movement of execution box 5, a variety of sewing actions can be performed, achieving efficient sewing operations. As mentioned earlier, the detour movement of execution box 5 can avoid overstitching caused by the upper thread and improve sewing quality. However, the detour movement of box 5 takes too much time, inevitably reducing the overall sewing productivity. Depending on the target sewing product, sometimes it is desirable to avoid productivity reduction rather than quality reduction caused by overstitching. For example, when sewing hidden parts that are not visible on the surface of the product, it is considered that overstitching improvement should not be performed, prioritizing productivity. In addition, sometimes it is desirable to select whether to control the detour movement of box 5 based on the material being sewn (processed fabric) or the type of upper thread. Furthermore, the degree of requirement to avoid overstitching may differ in simple straight sewing and complex embroidery sewing. To address these various situations, it is beneficial to have a function to select whether the detour movement of box 5 is enabled (Yes or ON) or disabled (No or OFF).

[0151] Items numbered 22-24 are units for setting parameters a, b, and c; specifically, they are equivalent to those used for the first region S1 and the second region S2. Figure 16 This is a setting unit that allows for variable settings of the range of [specific parameters]. Parameters a, b, and c specify the needle movement direction (stitch formation direction) for frame detour control. In items 22 and 23, the boundary angles a and b of the first region S1 are variablely set. In the boundary angles b and c of the second region S2, b conforms to the setting in item 23, and c is variablely set in item 24. As an example, for each boundary angle a, b, and c, predetermined values ​​(e.g., a = 85 degrees, b = 112 degrees, c = 210 degrees) are initially set, and variable settings are achieved by manually increasing or decreasing these values. Based on these settings (the values ​​of each boundary angle a, b, and c), [the following is performed / performed]. Figure 19 The determination of regions S0 and S1 in steps St4 and St8.

[0152] Typically, it is difficult to strictly define the area where the wrapped stitches occur. Therefore, if set on the safety side, the range of the areas S1 and S2 for frame detour control can be set wider to control the detour movement of frame 5. However, the more detour movement control of frame 5, the more likely the overall production efficiency will decrease. In addition, depending on the sewing product being sewn, in sewing of areas where stitch quality is not a concern, sometimes it is desirable to minimize the reduction in production efficiency by allowing wrapped stitches. Furthermore, sometimes the range of the areas S1 and S2 for frame detour control is not fixed, but is set variably according to the material being sewn (processed fabric) or the type of thread used. To address these various situations, it is beneficial to have the function of variably setting the range of the designated areas S1 and S2 (the values ​​of each boundary angle a, b, c) for frame 5 detour movement control.

[0153] Items 25 and 26 are units that define parameters X1 and Y1 for the first movement direction in the frame detour control (i.e., setting units for variably setting the detour movement path of frame 5), specifically, equivalent to units for setting the first intermediate point m1 ( Figure 17 The setting unit is used to variably set the XY displacement coordinate position (relative coordinate position relative to the base point C). Items 27 and 28 are units for setting the parameters X2 and Y2 that define the second movement direction in the frame detour control (setting units for variably setting the detour movement path of the frame), specifically, equivalent to the unit used to set the second intermediate point m2 ( Figure 17 This is a setting unit that allows for variable setting of the XY displacement coordinates (relative coordinates to the first intermediate point m1). For these parameters X1, Y1, X2, and Y2, initial values ​​can be preset, and these values ​​can be manually increased or decreased by the user for variable setting. Furthermore, in... Figure 24 The examples show the current values ​​(2.5mm, -3.8mm, 1.1mm) of parameters X1, Y1, X2, and Y2. Figure 1 The line trace is represented in XY coordinate form. For example, the XY displacement coordinates used to specify the position of the first intermediate point m1 (X1 = 2.5mm, Y1 = 2.5mm) belong to... Figure 1 The XY coordinate representation of the line traces shown indicates that the positions of the line traces in the X+ and Y+ quadrants are 180 degrees opposite to the direction of movement of the corresponding box 5, therefore they belong to the X- and Y- quadrants. Figure 17 In this context, the movement of frame 5 from base point C towards the first intermediate point m1 in the left-front direction corresponds to this movement. Additionally, the XY displacement coordinates (X2 = -3.8 mm, Y2 = 1.1 mm) used to define the position of the second intermediate point m2 indicate its location. Figure 1 The XY coordinate representation of the line traces shown indicates that the positions of the line traces in the X- and Y+ quadrants are 180 degrees opposite to the direction of movement of the corresponding box 5, therefore they belong to the X+ and Y- quadrants. Figure 17 In this context, the movement of box 5 from the first midpoint m1 to the second midpoint m2 located in the right-front direction corresponds to this movement. Based on the settings here (specifying the values ​​of parameters X1, Y1, X2, and Y2 for the first and second midpoints m1 and m2), the following is performed: Figure 19 The detour movement control in step St9 and box 5 in St10.

[0154] In this way, the parameters X1, Y1, X2, and Y2 of the movement direction in the detour control of frame 5 can be variably set, thereby appropriately changing the detour movement path of frame 5. For example, if a relatively large detour movement path is set, the upper seam thread can be reliably wound around the guide body 23 of the presser foot device 21; however, the time required for the detour movement of frame 5 is too long, thus reducing the overall sewing production efficiency. Conversely, if a relatively small detour movement path is set, less time is required for the detour movement of frame 5, resulting in good overall sewing production efficiency. Therefore, such a setting unit is beneficial because it can set an appropriate frame detour path while prioritizing either sewing quality or production efficiency.

[0155] Items 29 and 30 are units used to set the effective minimum and maximum stitch lengths for application box detour control. The effective minimum stitch length refers to the minimum value of the stitch length (line length) controlled by the application box detour, and the effective maximum stitch length refers to the maximum value of the stitch length (line length) controlled by the application box detour. As an example, 0.0mm is initially set as the effective minimum stitch length, and 36.0mm is initially set as the effective maximum stitch length. These values ​​can be appropriately increased or decreased to set the desired effective minimum or maximum stitch length. When applying this setting to box detour control, for example, if the length (line length) of the stitch to be formed next is within the range of the set effective minimum and effective maximum stitch lengths, then it is sufficient to configure detour control for execution box 5. For example, it can be configured as follows: Figure 19 Between steps St3 and St4 (or Figure 25 Between steps St11 and St4, insert a step to determine whether the next stitch length should fall within the range between the set effective minimum stitch length and effective maximum stitch length. If the result of this step is YES, proceed to step St4; if it is NO, jump to step St5.

[0156] Furthermore, the structure for setting various data (circumvention control conditions) associated with frame detour control is not limited to a structure performed manually by the user through the operation panel 6 of the sewing machine as described above. It can also be arbitrarily set as program data for frame detour control when creating a desired sewing pattern program or embroidery pattern program, or it can be a structure stored together with the data of that sewing pattern program or embroidery pattern program. A structure that provides various data (i.e., detour control conditions) associated with frame detour control in the form of such programmed data is also included in one embodiment of a setting unit that allows for variable setting of various data (detour control conditions) associated with frame detour control.

[0157] Furthermore, in the above embodiments, when the frame 5 makes a roundabout movement, needle bar jump control based on the jump mechanism is performed together with the frame roundabout movement control. However, this is not a limitation; the invention can be implemented even in sewing machines that do not have a jump mechanism for controlling the jump of the needle bar. In sewing machines without this jump mechanism, in order to make the frame 5 make a roundabout movement, it is sufficient to control the movement of the needle bar so that the needle does not fall during the roundabout movement of the frame 5. For example, by reducing the rotational speed of the spindle 13 during the roundabout movement of the frame 5, it is possible to control the needle so that it does not fall during the roundabout movement of the frame 5.

[0158] In the above embodiments, examples of applying the present invention to multi-head and multi-needle sewing machines have been described. However, it is not limited to this; the present invention can also be applied to single-head or single-needle sewing machines. Furthermore, the present invention can also be applied to any type of embroidery sewing machine or conventional sewing machine. Additionally, the holder (frame) for holding the workpiece is not limited to a planar type, but can also be a rotating type such as a hat frame. Furthermore, the rotary hook is not limited to a fully rotating vertical rotary hook (DB type), but can also be a horizontal rotary hook, a half-rotating rotary hook, or any other type of rotary hook. Depending on the type of rotary hook used and its rotation direction, the area where the stitches are generated may differ from the above embodiments, but corresponding area determination can be performed, or the corresponding needle plate structure can be modified (by changing the arrangement of the guide hole 31 and the groove 32), or the corresponding rotary hook structure can be modified (by changing the arrangement of the recess 52), etc.

[0159] The operation panel 6 can be configured to be fixedly mounted on the sewing machine, or it can be configured to be detachably mounted on the sewing machine. As a variation, a portable operation panel (e.g., a mobile computer or portable terminal) can be configured as a setting unit (i.e., a setting device) for manually setting the conditions of the various detour controls, wherein the portable operation panel is configured to be able to manually set, as referred to... Figure 24The conditions for various detour controls are described. In this case, the setting unit, which is composed of such a portable operation panel, has a communication function that allows communication with the control device of the sewing machine, and the sending and receiving of setting information / data between the two. Of course, the setting unit (i.e., the setting device) for manually setting the conditions for the various detour controls can also be configured to be able to use both the operation panel 6, which is fixedly or detachably mounted on the sewing machine, and the aforementioned portable operation panel.

Claims

1. A rotary hook structure for a sewing machine, characterized in that, It comprises: a spool housing that rotatably houses a spool of lower sewing thread wound on it; an inner shuttle that houses the spool housing; and an outer shuttle that rotates around the inner shuttle in sync with the up-and-down movement of the needle. The upper front surface of the inner shuttle has a needle drop hole, and the outer shuttle has a pointed end for capturing the upper sewing thread loop. On the upper front surface of the inner rotary hook, a recess is formed at a position deviating from the rotation direction of the needle drop hole towards the outer rotary hook. This recess has openings on its front and upper / lower sides, and a wall surface on its inner side. The spool housing is provided with a thread-taking component, which is used to direct the lower sewing thread led out from the lower sewing spool toward the recess of the inner rotary hook. The lower sewing thread, derived from the lower sewing spool within the spool housing, is led upwards via the thread-taking component and through the opening of the recess. The movement of the lower seam in the inward direction from the opening of the recess is restricted by the inner wall of the recess formed by the inner rotary hook.

2. The rotary hook structure of the sewing machine according to claim 1, characterized in that, The wire-taking component is composed of a spring component.

3. The rotary hook structure of the sewing machine according to claim 1, characterized in that, The thread-taking component has a free end and a fixed end. The thread-taking component is fixed to the spool housing via the fixed end. An annular or curved annular portion is formed at the free end to allow the lower sewing thread led out from the lower sewing spool to pass through.

4. The rotary hook structure of the sewing machine according to claim 3, characterized in that, The suture taking component is oscillating as the lower suture moves through the annular portion.

5. The rotary hook structure of the sewing machine according to claim 1, characterized in that, The wire-taking component is positioned below the recess.

6. The rotary hook structure of the sewing machine according to claim 1, characterized in that, The external rotary shuttle has an upper spring portion disposed around the tip portion, and the external rotary shuttle is formed such that the front side edge of the upper spring portion does not extend further forward than the front side edge of the tip portion.

7. The rotary hook structure of the sewing machine according to claim 1, characterized in that, The inner rotary shuttle has a raised portion formed on the outer periphery of its front surface, and the raised portion is distributed over a range of less than 90 degrees from the recess to the outer rotary shuttle in the direction of rotation.

8. The rotary hook structure of the sewing machine according to claim 1, characterized in that, The inner wall of the recess of the inner rotary shuttle is configured to be located further forward of the rotation trajectory of the side edge of the tip of the outer rotary shuttle.

9. The rotary hook structure of the sewing machine according to claim 1, characterized in that, In the spool housing, a guide member is provided in front of the take-up member, the guide member having a guide surface formed to connect with the front surface of the spool housing.

10. The rotary hook structure of the sewing machine according to claim 9, wherein, The guide surface of the guide member is provided with an opening that extends through in the front-rear direction.

11. A sewing machine, wherein, The sewing machine has: The rotary shuttle structure as described in any one of claims 1 to 10; A sewing mechanism that moves the needle through which the upper thread passes up and down, and rotates the outer rotary hook synchronously with the up and down movement of the needle, thereby causing the upper thread to wrap around the lower thread to sew the workpiece. as well as A feeding mechanism that displaces a holder holding the workpiece relative to the needle drop position, thereby forming a stitch in any direction on the workpiece.

12. The sewing machine according to claim 11, wherein, The sewing machine also has: The determination unit determines whether the direction of forming the next stitch belongs to the specified area corresponding to the added stitch. as well as The detour control unit, when determining that it is in the designated area, uses the feed mechanism to move the holding body, thereby causing the upper suture extending downward from the needle to detour in the direction corresponding to the perfect stitch, and then moves the holding body to the target position corresponding to the next stitch.

13. The sewing machine according to claim 12, wherein, The sewing machine also has a jump-up mechanism that, during the sewing operation, should perform jump-up control to prevent the needle from descending and instead keep it upright. The detour control unit uses the jump mechanism to perform the jump control, and uses the feed mechanism to control the movement of the holding body.

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