sewing machine

Abstract

To reduce the amount of a bobbin thread to be discarded.SOLUTION: A sewing machine 100 includes: a moving mechanism 40 for moving an object to be sewn with respect to a sewing needle 11; and a control device 120 for controlling the moving mechanism on the basis of sewing pattern data 123a for performing sewing according to a sewing pattern. It also includes a bobbin replacement device 50 for replacing a bobbin 34 of a shuttle device 30. The control device determines whether or not a bobbin thread wound around the bobbin 34 is sufficient for sewing the next sewing element, every time the sewing of a plurality of sewing elements p1-p3 in which a series of sewing operations on the basis of the sewing pattern is divided with the execution of thread cutting being a break point, and according to the determination result, it performs control for replacing the bobbin by the bobbin replacement device.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a sewing machine. [Background technology]

[0002] 2. Description of the Related Art An electronic cycle stitch sewing machine that automatically sews a series of sewing patterns in accordance with predetermined sewing pattern data may be equipped with a bobbin changing device that changes bobbins. Such sewing machines monitor the remaining amount of bobbin thread and, when the remaining amount of bobbin thread wound on the bobbin is insufficient to be consumed in one sewing pattern, control is performed to replace the bobbin (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-190881 Summary of the Invention [Problem to be solved by the invention]

[0004] When the remaining length of bobbin thread is insufficient to cover the length required for one sewing pattern, the bobbin thread is discarded when it is replaced. However, if the remaining length of bobbin thread is slightly insufficient to cover the length required for one sewing pattern, the length of bobbin thread discarded increases as a result of the replacement, resulting in increased wasted bobbin thread.

[0005] An object of the present invention is to reduce the amount of bobbin thread that is discarded. [Means for solving the problem]

[0006] The invention described in claim 1 is a sewing machine, a moving mechanism for moving the sewing object relative to the sewing needle; In order to perform stitching according to one sewing pattern, data indicating the order of needle drop positions and their position coordinates for forming the sewing pattern and operation commands are included. a control device for controlling the movement mechanism based on sewing pattern data, A bobbin changing device is provided for changing the bobbin of the shuttle device. The sewing pattern of the sewing pattern data is composed of a plurality of sewing elements, which are smaller patterns, and thread trimming is performed for each final stitch of each sewing element; The control device The aforementioned Multiple stitching elements Within The length of bobbin thread consumed for each stitch is calculated, of the plurality of sewing elements Within Each time a stitch is made, the cumulative total length from the start of use of the bobbin to the present is calculated based on the length of bobbin thread consumed in the sewing element, the length of bobbin thread consumed in the next sewing element is added to the total length, and whether the added value exceeds the sewable length of the bobbin is used to determine whether the bobbin wound on the bobbin is sufficient for sewing the next sewing element, and the bobbin changing device is controlled to change the bobbin depending on the result of the determination.

[0007] The invention described in claim 2 is a sewing machine, a moving mechanism for moving the sewing object relative to the sewing needle; In order to perform stitching according to one sewing pattern, data indicating the order of needle drop positions and their position coordinates for forming the sewing pattern and operation commands are included. a control device for controlling the movement mechanism based on sewing pattern data, a bobbin changing device for changing the bobbin of the shuttle device; a remaining thread detecting means for detecting the length of the remaining thread of the bobbin taken out from the shuttle device by the bobbin changing device, The sewing pattern of the sewing pattern data is composed of a plurality of sewing elements, which are smaller patterns, and thread trimming is performed for each final stitch of each sewing element; The control device The aforementioned Multiple stitching elements Within The length of bobbin thread consumed for each stitch is calculated, of the plurality of sewing elements Within Each time one sewing operation is performed, it is determined whether or not the bobbin thread wound on the bobbin is sufficient for sewing the next sewing element, and in accordance with the determination result, the bobbin changing device is controlled to change the bobbin; The plurality of sewing elements calculated based on the sewing pattern data WithinThe length of the lower thread consumed for each bobbin is corrected based on the length of the lower thread remaining on the bobbin detected by the remaining thread detecting means. [Effects of the Invention]

[0009] The present invention determines whether the bobbin thread wound on the bobbin is sufficient for sewing the next sewing element each time sewing of a sewing element is performed, and therefore makes it possible to shorten the remaining length of the bobbin thread on the bobbin removed from the shuttle device for replacement in accordance with the length of the bobbin thread consumed by the sewing element. Therefore, it is possible to reduce the amount of lower thread that is discarded. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. [Figure 2] FIG. 2 is an enlarged perspective view of the sewing machine around the needle plate. [Figure 3] FIG. 2 is a perspective view of a shuttle device, a bobbin changing device, a lower thread winding device, and a residual thread removing device. [Figure 4] 4 is an explanatory diagram showing the holding positions of the bobbin case and the bobbin by the bobbin changing device. FIG. [Figure 5] FIG. 2 is a block diagram showing a control system of the sewing machine. [Figure 6] 6A and 6B are explanatory diagrams showing the control contents of the bobbin replacement control, in which FIG. 6A shows the target winding length wound onto the bobbin by the bobbin winding device, FIG. 6B shows the bobbin thread length consumed by sewing one sewing pattern, FIG. 6C shows the sewable range of multiple sewing elements of the sewing pattern relative to the sewable length of the bobbin, FIG. 6D shows the relationship between the target winding length onto the bobbin, the length of residual thread remaining on the bobbin, and the actual consumed length of the bobbin thread, and FIG. 6E shows the bobbin thread length consumed by sewing one sewing pattern after correction. [Figure 7] 10 is a flowchart showing the flow of bobbin replacement control. DETAILED DESCRIPTION OF THE INVENTION

[0011] [Summary of the embodiment of the invention] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a sewing machine according to the present invention will be described in detail with reference to the drawings. In this embodiment, an electronic cycle sewing machine will be described as an example of the sewing machine. FIG. 1 is a perspective view of an electronic cycle sewing machine 100, and FIG. 2 is an enlarged perspective view of the area around the sewing needle. The electronic cycle sewing machine 100 has a holding frame that holds the workpiece, and the holding frame moves relative to the sewing needle to form stitches based on predetermined sewing pattern data on the workpiece held in the holding frame. Here, the direction in which the sewing needle 11 described later moves up and down is defined as the Z-axis direction (up and down direction), one direction perpendicular to this is defined as the X-axis direction (left and right direction), and the direction perpendicular to both the Z-axis direction and the X-axis direction is defined as the Y-axis direction (front and back direction).

[0012] As shown in FIG. 1, the electronic cycle sewing machine 100 (hereinafter referred to as the sewing machine 100) includes a sewing machine main body 101 provided on the top surface of the sewing machine table T, a pedal R provided on the bottom of the sewing machine table T for operating the sewing machine main body 101, and an operation panel 300 provided on the top of the sewing machine table T for the user to perform input operations. The sewing machine body 101 also includes a sewing machine frame 20, a needle up-down movement mechanism, a movement mechanism 40, a shuttle device 30, a bobbin changing device 50, a lower thread winding device 60, and a residual thread removing device 70.

[0013] [Sewing machine frame and main shaft] 1 and 2, the sewing machine body 101 is provided with a sewing machine frame 20 having an external shape that is approximately U-shaped in side view. The sewing machine frame 20 has a sewing machine arm portion 21 that forms the upper part of the sewing machine body 101 and extends in the Y-axis direction, a sewing machine bed portion 22 that forms the lower part of the sewing machine body 101 and extends in the Y-axis direction, and an upright body portion 23 that connects the sewing machine arm portion 21 and the sewing machine bed portion 22. The sewing machine body 101 has a power transmission mechanism disposed within the sewing machine frame 20, and has a main shaft (not shown) that is rotatable and extends in the Y-axis direction, and a lower shaft 14 (see FIG. 3). The main shaft is rotatably supported within the sewing machine arm portion 21, and the lower shaft 14 is rotatably supported within the sewing machine bed portion 22.

[0014] The main shaft is connected to a sewing machine motor 15 (see FIG. 5), and a rotational force is applied by this sewing machine motor 15. In addition, a lower shaft (not shown) is connected to the main shaft via a timing belt and a sprocket (not shown), and when the main shaft rotates, the power of the main shaft is transmitted to the lower shaft 14 via the timing belt and the sprocket, causing the lower shaft 14 to rotate at twice the speed of the main shaft. The front end of the lower shaft 14 is connected to the shuttle device 30. When the lower shaft 14 rotates together with the main shaft, the needle 11 and the outer shuttle 31 of the shuttle device 30 cooperate to form a stitch.

[0015] [Needle vertical movement mechanism] A needle bar 12, which holds a sewing needle 11 at its lower end, is supported so as to be movable up and down at the front end of the sewing machine arm portion 21. Inside the front end of the sewing machine arm portion 21, there are provided a needle bar crank fixed to the front end of the main shaft, a needle bar holder fixed to the needle bar 12, and a crank rod connecting the needle bar crank and the needle bar holder. A small frame-shaped presser foot 13, into which the sewing needle 11 can be loosely inserted, is disposed below the needle bar 12. The presser foot 13, located at the front end of the sewing machine arm 21, moves up and down in conjunction with the up and down movement of the needle bar 12 to prevent the sewing material from lifting up due to the up and down movement of the sewing needle 11.

[0016] The needle bar crank rotates together with the main shaft. One end of the crank rod is connected to the rotational circumference of the needle bar crank so as to be rotatable around the Y axis, and the other end is connected to the needle bar holder around the Y axis. Therefore, when the main shaft is rotated by the sewing machine motor 15, one end of the crank rod performs an orbital motion, and only the up and down motion, which is the Z-axis component of the orbital motion, is transmitted to the other end, thereby imparting up and down motion to the needle bar 12. That is, the sewing machine motor 15, the main shaft, the needle bar crank, the needle bar holder, the crank rod, and the needle bar 12 constitute a needle up-down movement mechanism that moves the sewing needle 11 up and down. The needle up-down movement mechanism is similar to a well-known configuration, and therefore each component is not shown in the drawings.

[0017] [Movement mechanism] As shown in FIGS. 1 and 2, a needle plate 24 is disposed on the sewing machine bed portion 22 along the XY plane. The moving mechanism 40 includes a holding frame 41 consisting of a presser foot and a lower plate that hold the sewing material on the needle plate 24, a support base 42 that supports the presser foot of the holding frame 41 so that it can be raised and lowered, and an actuator (not shown) that serves as the driving source for the raising and lowering movement of the presser foot. Furthermore, the movement mechanism 40 is equipped with an X-axis motor 43 and a Y-axis motor 44 that move and position the holding frame 41 and the support base 42 along the XY plane via a belt mechanism (not shown) built into the sewing machine bed portion 22 (see Figure 5). The holding frame 41 clamps the sewing material and moves the held sewing material in the front-rear and left-right directions by driving the X-axis motor 43 and the Y-axis motor 44. The movement of the holding frame 41 is linked to the operation of the sewing needle 11 and the shuttle (not shown), so that stitches can be formed on the sewing material at a plurality of needle drop positions that make up a predetermined sewing pattern.

[0018] [pedal] The pedal R operates as an operation pedal for driving the sewing machine 100 to perform a sewing operation. The pedal R incorporates a sensor for detecting the position at which the pedal R is depressed, and an output signal from the sensor is input as an operation signal for the pedal R to a control device 120, which will be described later. The control device 120 controls the driving of the sewing machine 100 and the execution of other operations in response to an operation signal corresponding to the operation position.

[0019] [Operation Panel] Sewing machine 100 is also provided with an operation panel 300 for a user to input operations, and various data and operation signals input to operation panel 300 are input to control device 120, which will be described later. The operation panel 300 is configured with a display unit 300b consisting of a liquid crystal display panel and a touch sensor 300c provided on the display screen of the display unit 300b. By touching various operation keys etc. displayed on the liquid crystal display panel, the touch panel detects the touched position and outputs an operation signal corresponding to the detected position to the control device 120 described later.

[0020] [Kettle device] FIG. 3 is a perspective view of the shuttle device 30, the bobbin changing device 50, the lower thread winding device 60, and the residual thread removing device 70, and FIG. 4 is an explanatory diagram showing the holding positions of the bobbin case 33 and the bobbin 34 by the bobbin changing device 50. As shown in FIG. 3, the shuttle device 30, the bobbin changing device 50, the lower thread winding device 60 and the residual thread removing device 70 are disposed inside the sewing machine bed portion 22 and below the needle plate 24.

[0021] The shuttle device 30 includes an outer shuttle 31 fixed to the front end of the lower shaft 14, an inner shuttle 32 disposed inside the outer shuttle, and a bobbin case 33 and a bobbin 34 removably stored inside the inner shuttle 32. The bobbin 34 comprises a cylindrical shaft portion and flange portions provided at both ends thereof, and can store the bobbin thread by winding it around the outer periphery of the shaft portion between the flange portions.

[0022] The bobbin case 33 is cylindrical with one end closed, and can store the bobbin 34 in a rotatable state. The bobbin case 33 is also equipped with an engaging member (not shown) that engages with the shaft portion of the inner hook 32. As shown in Fig. 4, a lock lever 331 that operates the engaging member is provided on the closed end surface of the bobbin case 33. This lock lever 331 is provided so as to be able to rise and fall and rotate from the closed end surface of the bobbin case 33, and by the lock lever 331 rotating up and down, the state in which the engaging member has engaged with the shaft portion of the inner hook 32 can be released. This allows the bobbin case 33 and the bobbin 34 to be removed from the inner hook 32.

[0023] [Bobbin changer] As shown in FIG. 3, the bobbin changing device 50 includes a guide shaft 51 parallel to the Y-axis direction and a rotating arm 52 that is rotatable around the guide shaft 51. The rotating arm 52 extends on both sides in the diametric direction of a circumference centered on the guide shaft 51, and holds the bobbin case 33 and the bobbin 34 (hereinafter referred to as "bobbin case 33, etc.") at the extended ends on both sides. 4, a shuttle attaching / detaching position A, a residual thread removal position B, and a bobbin thread winding position C are set at 120° intervals on a circumference centered on the guide shaft 51. That is, the shuttle device 30 is disposed at the shuttle attaching / detaching position A, the residual thread removal device 70 is disposed at the residual thread removal position B, and the bobbin thread winding device 60 is disposed at the bobbin thread winding position C.

[0024] The guide shaft 51 is supported so as to be movable forward and backward along the Y-axis direction by a bobbin attachment / detachment solenoid 53. The guide shaft 51 also supports a rotating arm 52 and is supported so as to be rotatable integrally with the rotating arm 52 about the Y-axis. The cross section of the guide shaft 51 is shaped like a spur gear, and is in mesh with a gear provided on the output shaft of a shuttle transport motor 54 (see FIG. 5). The guide shaft 51 is rotated in both directions in 60° increments by this shuttle transport motor 54, and the bobbin cases 33 held at both ends of the rotating arm 52 can be individually positioned at a shuttle attachment / detachment position A, a residual thread removal position B, and a bobbin thread winding position C.

[0025] Furthermore, the bobbin attaching / detaching solenoid 53 switches the position of the rotating arm 52 together with the guide shaft 51 back and forth along the Y-axis direction. As a result, at each of the shuttle attaching / detaching position A, residual thread removal position B, and bobbin thread winding position C, the bobbin case 33 and other items held by the rotating arm 52 are attached to the shuttle device 30, residual thread removal device 70, or bobbin thread winding device 60 when the rotating arm 52 moves forward, and the bobbin case 33 and other items held by the rotating arm 52 are detached from the shuttle device 30, residual thread removal device 70, or bobbin thread winding device 60 when the rotating arm 52 moves backward.

[0026] Both rotating ends of the rotating arm 52 are provided with bobbin case holding mechanisms (not shown), which allow the bobbin case 33 and the like to be attached and detached. This bobbin case holding mechanism can employ well-known configurations such as the electromagnet (symbol 40A) of the automatic bobbin thread supply device described in Japanese Patent Application Laid-Open No. 5-192476 or the pivotable lever claw (symbol 8c) of the bobbin gripping means (symbol 8) described in Japanese Patent Application Laid-Open No. 6-304369.

[0027] [Bobbin thread winding device] The bobbin thread winding device 60 includes a coupling 61 that abuts against the bobbin 34 in the bobbin case 33 held by the pivoting arm 52, a winding motor 62 that rotates the bobbin 34 via the coupling 61, and a bobbin thread cutting device 63 that holds and cuts the end of the bobbin thread that is unwound from the spool. In this lower thread winding device 60, the number of revolutions of the winding motor 62 is detected by an encoder 621 (see FIG. 5), and the length of the thread wound around the bobbin 34 is controlled based on the number of revolutions. The bobbin thread winding device 60 can employ well-known configurations such as the bobbin thread winding mechanism (symbol 50) described in Japanese Patent Application Laid-Open No. 5-192476, the thread clamping arm (symbol 62) and its drive unit, the thread holding base (symbol 70), the bobbin thread cutting mechanism (symbol 80), etc.

[0028] [Residual thread removal device] The residual thread removal device 70 includes a suction nozzle (not shown) that sucks in the end of the bobbin thread hanging down from the bobbin case 33 or the like, a bobbin thread winding shaft 71 provided near the end of the bobbin thread drawn into the suction nozzle, a winding motor 72 (see FIG. 5) that serves as the rotary drive source for the bobbin thread winding shaft 71, an actuator that moves the bobbin thread winding shaft 71 and the winding motor 72 back and forth in the axial direction, and a stopper plate (not shown) that slides on the outer periphery of the bobbin thread winding shaft 71 and removes the bobbin thread wound around the bobbin thread winding shaft 71, which is moved back by the actuator. In this residual thread remover 70, the number of rotations of the winding motor 72 is detected by an encoder 721 (see FIG. 5), and the length of the residual thread remaining on the bobbin 34 is acquired by the control device 120 based on the number of rotations. Therefore, the encoder 721 functions as residual thread detection means for detecting the length of the lower thread remaining on the bobbin 34 removed from the shuttle device 30. The remaining thread removing device 70 may employ a known configuration such as the remaining thread removing device (reference numeral 6) described in Japanese Patent Laid-Open Publication No. 7-80177.

[0029] [Sewing machine control system: control device] FIG. 5 is a block diagram showing the control system of the sewing machine 100. The sewing machine 100 includes a control device 120 as operation control means for controlling the operation of each of the above-mentioned parts. The control device 120 includes a program memory 122 in which a sewing program 122a, a bobbin replacement control program 122b, and various other programs are stored, a data memory 123 as storage means in which sewing pattern data 123a, bobbin thread consumption data 123b, and various setting information (not shown), and a CPU 121 that executes the programs 122a, 122b, etc. in the program memory 122.

[0030] Furthermore, CPU 121 is connected to operation panel 300 via interface 131. Operation panel 300 has display unit 300b that displays various screens and input buttons, and touch sensor 300c that is provided on the surface of display unit 300b and detects the contact position on the display unit 300b, and functions as an input / output means for various information. All of the input buttons and input switches used on operation panel 300 are displayed on display unit 300b, and input is detected by touch sensor 300c, so that they function in the same way as push-buttons and switches. The operation panel 300 also has a function of arbitrarily setting parameters for the sewing pattern data 123a and a function of selecting desired data from among a plurality of sewing pattern data 123a.

[0031] CPU 121 is also connected via interface 124 to a sewing machine motor drive circuit 15b that drives sewing machine motor 15, and controls the rotation of sewing machine motor 15. Sewing machine motor 15 is also provided with an encoder 151 that detects the number of rotations. The sewing machine motor 15 may be, for example, a servo motor.

[0032] In addition, the CPU 121 is connected to an X-axis motor drive circuit 43b and a Y-axis motor drive circuit 44b via an interface 125 and an interface 126, which drive an X-axis motor 43 and a Y-axis motor 44, respectively, to move the sewing workpiece in the X-axis and Y-axis directions, and controls the movement of the sewing workpiece.

[0033] In addition, the CPU 121 is individually connected via an interface 127 and an interface 128 to a bobbin attaching / detaching solenoid drive circuit 53b and a shuttle transport motor drive circuit 54b, which respectively drive the bobbin attaching / detaching solenoid 53 and the shuttle transport motor 54 of the bobbin changing device 50, and controls the operation of the bobbin changing device 50.

[0034] Furthermore, the CPU 121 is connected via an interface 129 to a winding motor drive circuit 62b that drives the winding motor 62 of the bobbin thread winding device 60, and controls the operation of the bobbin thread winding device 60. The winding motor 62 is also provided with an encoder 621 that detects the number of rotations thereof.

[0035] Furthermore, the CPU 121 is connected via the interface 130 to a winding motor drive circuit 72b that drives the winding motor 72 of the remaining thread removing device 70, and controls the operation of the remaining thread removing device 70. The winding motor 72 is also provided with an encoder 721 that detects the number of rotations thereof.

[0036] The CPU 121 is also connected to an operation panel 300 via an interface 131 .

[0037] [Sewing pattern data] The sewing pattern data 123a includes data indicating the order of needle drop positions and their position coordinates for all needle drop positions for forming the sewing pattern, as well as various operation commands, in order to perform stitching according to one sewing pattern. Specifically, one sewing pattern is made up of a plurality of (here, three) smaller pattern sewing elements p1 to p3, and the thread is cut by a thread cutting device (not shown) for each final stitch of each sewing element p1 to p3. Note that the "thread cutting device" referred to here does not refer to the bobbin thread cutting device 63 described above, but rather refers to a thread cutting device for cutting the upper thread and bobbin thread from the sewn material at the end of each sewing session. The number of sewing elements in the sewing pattern data 123a is an example, and is not limited to three, and may be any number.

[0038] [Overall operation control of the sewing machine] The operation control of the sewing machine 100 will now be briefly described. When sewing, the target sewing pattern data 123a is selected in advance through the operation panel 300 from among the plurality of sewing pattern data 123a stored in the data memory 123. Then, when the start of sewing is input by operating the pedal R, the CPU 121 of the control device 120 starts the sewing machine motor 15, reads the sewing pattern data 123a, and controls the X-axis motor 43 and Y-axis motor 44 so that the holding frame 41 is positioned in order from the first stitch of the leading sewing element p1. Then, when the needles have been inserted in order up to the final stitch of the sewing element p1, the CPU 121 executes thread cutting and similarly executes sewing operations for the next sewing elements p2 and p3.

[0039] The CPU 121 also controls the bobbin transport operation of the bobbin exchange device 50. That is, the CPU 121 controls the shuttle transport motor 54 to position one end of the guide shaft 51 at any one of positions A to C while the guide shaft 51 is moved forward by the bobbin attachment / detachment solenoid 53, and after positioning, the CPU 121 controls the bobbin attachment / detachment solenoid 53 to move the guide shaft 51 backward. Then, the bobbin case holding mechanism is operated to attach or detach the bobbin case 33 or the like to or from the shuttle device 30, the bobbin thread winding device 60 or the residual thread removing device 70.

[0040] Furthermore, the CPU 121 controls the bobbin thread winding device 60 to perform bobbin thread winding operation. That is, the bobbin thread winding device 60 is in a state of standby in which the bobbin thread unwound from the bobbin thread spool is tensioned so that it is entangled around the shaft of the bobbin 34, and when the guide shaft 51 is moved backward by the bobbin changing device 50, the coupling 61 comes into contact with the bobbin 34 in the bobbin case 33 held by the guide shaft 51. When the CPU 121 drives the winding motor 62, the end of the lower thread unwound from the spool is wound around the shaft of the bobbin 34, and winding of the lower thread begins. At this time, the CPU 121 counts the number of rotations of the winding motor 62 detected by the encoder 621. The control device 120 stores table data indicating the relationship between the rotation speed of the winding motor 62 and the winding length of the bobbin thread in the data memory 123. The CPU 121 then rotates the winding motor 62 until the rotation speed reaches a preset target winding length, and then stops the motor, and causes the bobbin thread cutting device 63 to cut the bobbin thread. This allows the lower thread to be wound onto the bobbin 34 by the target winding length.

[0041] Furthermore, the CPU 121 controls the remaining thread removing device 70 to perform the remaining thread removing operation. That is, when the guide shaft 51 is moved backward by the bobbin changing device 50, the CPU 121 starts a suction operation using the suction nozzle, and pulls in the end of the remaining bobbin thread hanging down from the bobbin case 33. Then, the CPU 121 starts driving the winding motor 72, and winds the remaining bobbin thread onto the bobbin thread winding shaft 71. At this time, CPU 121 counts the number of rotations of winding motor 72 detected by encoder 721. The control device 120 stores in a data memory 123 table data that indicates the relationship between the rotation speed of the winding motor 72 and the length of the bobbin thread that is wound. Then, when the CPU 121 detects the completion of winding from a sensor that detects the passage of the remaining bobbin thread, which is located near the bobbin thread winding shaft 71, or from a change in the value of the current flowing to the winding motor 72, it detects the length of the remaining thread remaining on the bobbin 34 from the number of rotations of the winding motor 72 until winding is completed.

[0042] [Bobbin exchange control] The CPU 121 of the control device 120 executes bobbin exchange control based on the bobbin exchange control program 122b. The control content of this bobbin exchange control will be described below with reference to FIG. As shown in FIG. 6(A), the target winding length l0 to be wound onto the bobbin 34 by the bobbin thread winding device 60 described above is the sum of the sewable length l1 that is expected to be actually consumed in sewing and the remaining thread allowance length l2 that is reserved in advance. On the other hand, as shown in Fig. 6(B), the bobbin thread length Y0 consumed in sewing one sewing pattern is the sum of the bobbin thread lengths Y1, Y2, and Y3 consumed by each of the sewing elements p1 to p3. Note that the symbol i in the figure indicates the execution of thread trimming. The CPU 121 calculates the values ​​of the bobbin thread lengths Y1, Y2, Y3 consumed in each sewing element p1 to p3 by calculating the movement amount of the holding frame at each needle point from the position coordinates of the needle point position of each sewing element p1 to p3 recorded in the sewing pattern data, and then calculates it from the total value of the movement amount for each sewing element p1 to p3. The calculated lower thread lengths Y1, Y2, Y3 are recorded in the data memory 123 as part of the lower thread consumption data 123b.

[0043] Here, bobbin replacement control will be explained using an example in which the bobbin thread length Y0×2 consumed by sewing two sewing patterns is shorter than the sewable length l1 of the bobbin 34, and the bobbin thread length Y0×3 consumed by sewing three sewing patterns is longer than the sewable length l1 of the bobbin 34. The CPU 121 adds up the length of the lower thread consumed from the start of use of the bobbin in units of the sewing elements p1 to p3 of each sewing pattern in order, and compares it with the sewable length l1 of the bobbin . For example, even if the bobbin thread length Y0×3 consumed by sewing three sewing patterns is longer than the sewable length l1 of the bobbin 34, if the total length up to the sewing element p1 or p2 of the third sewing pattern is shorter than the sewable length l1, sewing will be performed up to the maximum sewable sewing element. Here, we will illustrate the case where the cumulative total length lc up to the sewing element p2 of the third sewing pattern is the value closest to the sewable length l1. Therefore, the CPU 121 performs control so that sewing is performed up to the sewing element p2 of the third sewing pattern, and after thread cutting, the bobbin 34 is replaced.

[0044] In addition, the consumed length of the bobbin thread may not completely match the calculated value calculated from the sewing pattern data due to, for example, differences in the thickness and material of the sewn material, the set thread tension, and the elasticity of the bobbin thread used. Therefore, the CPU 121 of the control device 120 detects the length of the residual yarn remaining on the bobbin 34 that has been removed from the shuttle device 30 and transported to the residual yarn removal device 70 from the number of rotations of the winding motor 72 from the start to the completion of winding the residual yarn. Then, as shown in FIG. 6(D), the actual consumed lower thread length l11 is calculated by subtracting the remaining thread length l21 remaining on the bobbin 34 from the target winding length l0 on the bobbin 34. Theoretically, the actual consumed bobbin thread length l11 should match the cumulative total length lc up to the sewing element p2 of the third sewing pattern, but if they do not match, the CPU 121 calculates the error ratio (l11 / lc) between the consumed bobbin thread length l11 and the total length lc. The calculated error ratio (l11 / lc) is recorded in the data memory 123 as part of the bobbin thread consumption amount data 123b. Then, as shown in FIG. 6(E), when the CPU 121 calculates the lower thread lengths Y1, Y2, Y3 and Y0 to be consumed by each of the sewing elements p1 to p3 during the next sewing, the CPU 121 calculates corrected lower thread lengths Y11, Y21, Y31, Y01 by multiplying by the error ratio (l11 / lc), and determines the timing for replacing the bobbin 34 based on these corrected lower thread lengths.

[0045] [Bobbin exchange control operation explanation] The flow of bobbin exchange control performed by the CPU 121 of the control device 120 based on the bobbin exchange control program 122b will be described with reference to the flowchart shown in FIG. It is assumed that sewing will start with a bobbin 34 (referred to as a "new bobbin 34") wound with lower thread of the target winding length 10 attached to the inner hook 32 (see Figure 6(A)).

[0046] First, when the sewing pattern data 123a is selected from the operation panel 300 (step S1), the CPU 121 reads the sewing pattern data 123a and calculates the bobbin thread lengths Y1, Y2, Y3 consumed by each of the sewing elements p1 to p3 and the bobbin thread length Y0 consumed by sewing the sewing pattern (step S3: see FIG. 6(B)).

[0047] Next, CPU 121 starts sewing by starting sewing machine motor 15 (step S5). Then, each time sewing and thread trimming is performed for one of the sewing elements p1, p2, or p3 in the sewing pattern data 123a, the CPU 121 calculates the cumulative total length lc from the start of use of the new bobbin 34 to the present based on the aforementioned lower thread lengths Y1, Y2, Y3 (or Y11, Y21, Y31) (step S7: see Figure 6(C)). Furthermore, the CPU 121 adds the bobbin thread length Y1, Y2 or Y3 to be consumed in the next sewing element p1, p2 or p3 to be sewn to the cumulative total length lc since the start of use of the new bobbin 34, and determines whether the next sewing element p1, p2 or p3 to be sewn can be sewn depending on whether the calculated value exceeds the sewable length l1 of the bobbin 34 (step S9).

[0048] If the calculated value does not exceed the sewable length l1 of the bobbin 34 and it is determined that the sewing element p1, p2 or p3 to be sewn next can be sewn, the process proceeds to step S17. Furthermore, if the calculated value exceeds the sewable length l1 of the bobbin 34 and it is determined that the next sewing element p1, p2 or p3 to be sewn cannot be sewn, the CPU 121 removes the bobbin case 33 etc. from the inner hook 32 of the hook device 30 based on the bobbin transport operation control for the bobbin changing device 50 described above, and supplies the bobbin case 33 containing the bobbin 34 wound with the bobbin thread of the target winding length l0 by the bobbin thread winding device 60 (step S11).

[0049] In addition, the CPU 121 transports the bobbin case 33 and other items removed from the inner hook 32 of the shuttle device 30 to the residual thread removal device 70, and controls the residual thread removal operation to wind the lower thread remaining on the bobbin 34, and obtains the length l21 of the residual thread remaining on the bobbin 34 from the rotation speed detected by the encoder 721 (step S13). Furthermore, the CPU 121 calculates the actual consumed lower thread length l11 from the remaining thread length l21 (see FIG. 6(D)), and calculates the error ratio (l11 / lc) between the consumed lower thread length l11 and the total length lc (step S15). The value of this error ratio (l11 / lc) is registered in the data memory 123. Then, the process proceeds to step S17.

[0050] In step S17, the CPU 121 determines whether the sewing element p1, p2, or p3 to be sewn next is the last sewing element p3 in the sewing pattern data 123a (step S17). As a result, if it is determined that the sewing element to be sewn next is not the last sewing element p3 in the sewing pattern data 123a, the process proceeds to step S7, and sewing is performed for that sewing element. At this time, if the value of the error ratio (l11 / lc) has already been registered in the data memory 123 in step S15, the values ​​of the bobbin thread lengths Y1, Y2, Y3 used in calculating the cumulative total length lc in step S7 are corrected by multiplying them by the error ratio (l11 / lc).

[0051] Furthermore, if it is determined that the sewing element to be sewn next is the last sewing element p3 in the sewing pattern data 123a, the CPU 121 determines whether the sewing pattern data 123a to be sewn next has been changed to another sewing pattern data 123a (step S19). As a result, if it is determined that there is no change in the sewing pattern data 123a, the process returns to step S5, and sewing can again be started based on the current sewing pattern data 123a. Furthermore, if it is determined that the sewing pattern data 123a has been changed, the CPU 121 returns the process to step S3, reads the newly selected sewing pattern data 123a, and calculates the lower thread lengths Y1, Y2, Y3 consumed by each of the sewing elements p1 to p3 and the lower thread length Y0 consumed by sewing the sewing pattern. Note that when the sewing pattern data 123a is changed, the error ratio (l11 / lc) in the data memory 123 is reset.

[0052] [Technical Effects of the Embodiments of the Invention] In the sewing machine 100, the CPU 121 of the control device 120 determines whether the bobbin thread wound on the bobbin 34 is sufficient for sewing the next sewing element each time sewing elements p1 to p3, which are formed by dividing a series of stitches based on a sewing pattern, are sewn, and controls the bobbin changing device 50 to change the bobbin 34 depending on the result of the determination. Conventionally, each time a series of stitches based on a sewing pattern is performed, it is determined whether or not the bobbin thread wound on the bobbin 34 is sufficient for sewing the entire next sewing pattern. Therefore, even if the length of the remaining bobbin thread on the bobbin 34 removed from the shuttle device 30 for replacement is slightly less than the length of the bobbin thread consumed in one sewing pattern, the remaining bobbin thread is discarded. However, in the case of the above-mentioned sewing machine 100, each time sewing elements p1 to p3 are performed, it is determined whether the bobbin thread wound on the bobbin 34 is sufficient for sewing the next sewing element, so it is possible to make the remaining length of the bobbin thread on the bobbin 34 removed from the shuttle device 30 for replacement shorter than the bobbin thread length Y1, Y2 or Y3 consumed in sewing elements p1 to p3.

[0053] Furthermore, the CPU 121 of the control device 120 calculates the lower thread lengths Y1, Y2, Y3 consumed for each sewing of the plurality of sewing elements p1 to p3 based on the sewing pattern data 123a. Therefore, there is no need to include data indicating the bobbin thread lengths Y1, Y2, Y3 consumed for each sewing of sewing elements p1 to p3 in the sewing pattern data 123a in advance, and it is possible to obtain the bobbin thread lengths Y1, Y2, Y3 using existing sewing pattern data.

[0054] The sewing machine 100 also includes an encoder 721 that detects the remaining length l21 of the lower thread of the bobbin 34 that has been removed from the shuttle device 30 by the bobbin changing device 50, and the CPU 121 of the control device 120 corrects the lower thread lengths Y1, Y2, Y3 consumed for each sewing of the multiple sewing elements p1 to p3, calculated based on the sewing pattern data 123a, using an error ratio (l11 / lc) based on the remaining length l21 of the lower thread of the bobbin 34 detected by the encoder 721. Therefore, it is possible to improve the accuracy of determining whether the bobbin thread wound on the bobbin 34 is sufficient for sewing the next sewing element, and it is possible to more effectively reduce waste of the bobbin thread.

[0055] [others] The above describes the embodiments of the present invention. However, the present invention is not limited to the above embodiments. The details shown in the embodiments can be modified as appropriate without departing from the spirit of the invention. For example, the configurations of the shuttle device 30, the moving mechanism 40, the bobbin changing device 50, the lower thread winding device 60, and the residual thread removing device 70 are merely examples, and equivalent functions may be realized by different mechanisms.

[0056] Furthermore, the control device 120 calculates the bobbin thread lengths Y1, Y2, Y3 consumed for each sewing of the sewing elements p1 to p3 from the settings of the sewing pattern data 123a, but the sewing pattern data 123a may be configured to previously prepare data on the bobbin thread lengths Y1, Y2, Y3 consumed for each sewing of the sewing elements p1 to p3.

[0057] The length of the lower thread wound around the bobbin 34 or the remaining length l21 of the lower thread on the bobbin 34 may be detected from the number of rotations of a roller or the like through which the lower thread passes. In this case, the length of the lower thread can be detected in proportion to the number of rotations, which may result in higher detection accuracy. [Explanation of symbols]

[0058] 11 Sewing Needle 12 Needle bar 14 Lower axis 15 Sewing machine motor 24 Needle plate 30. Kettle device 33 Bobbin case 34 Bobbin 40 Moving mechanism 50 Bobbin changer 60 Bobbin thread winding device 70 Remaining thread removal device 100 Electronic Cycle Sewing Machine (Sewing Machine) 120 Control device 122a Sewing Program 122b Bobbin exchange control program 123 Data Memory 123a Sewing pattern data 123b Bobbin thread consumption data 721 Encoder (remaining thread detection means) p1~p3 elements

Claims

1. a moving mechanism for moving the sewing object relative to the sewing needle; a control device that controls the movement mechanism based on sewing pattern data that includes data indicating the order of needle points and their position coordinates for all needle points to form one sewing pattern, and operation commands, in order to perform stitch movement according to the sewing pattern, A bobbin changing device is provided for changing the bobbin of the shuttle device. The sewing pattern of the sewing pattern data is composed of a plurality of sewing elements, which are smaller patterns, and thread trimming is performed for each final stitch of each sewing element; The control device calculating a length of bobbin thread consumed each time one of the plurality of sewing elements is sewn; Each time one of the plurality of sewing elements is sewn, a cumulative total length from the start of use of the bobbin to the present is calculated based on the length of bobbin thread consumed by the sewing element, the length of bobbin thread consumed by the next sewing element is added to the total length, and whether the added value exceeds the sewable length of the bobbin is determined to be sufficient to sew the next sewing element, and the bobbin changing device is controlled to change the bobbin depending on the result of the determination.

2. a moving mechanism for moving the sewing object relative to the sewing needle; a control device that controls the movement mechanism based on sewing pattern data that includes data indicating the order of needle points and their position coordinates for all needle points to form one sewing pattern, and operation commands, in order to perform stitch movement according to the sewing pattern, a bobbin changing device for changing the bobbin of the shuttle device; a remaining thread detecting means for detecting the length of the remaining thread of the bobbin taken out from the shuttle device by the bobbin changing device, The sewing pattern of the sewing pattern data is composed of a plurality of sewing elements, which are smaller patterns, and thread trimming is performed for each final stitch of each sewing element; The control device calculating a length of bobbin thread consumed each time one of the plurality of sewing elements is sewn; Each time one of the plurality of sewing elements is sewn, it is determined whether or not the bobbin thread wound on the bobbin is sufficient for sewing the next sewing element, and in accordance with the determination result, the bobbin changing device is controlled to change the bobbin; a bobbin thread length calculated based on the sewing pattern data and consumed for each of the plurality of sewing elements is corrected based on the remaining length of the bobbin thread detected by the remaining thread detecting means.

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