JP2024039799A - sewing equipment - Google Patents

Abstract

An object of the present invention is to provide a sewing device that can form more stable stitches than conventional ones at the start of sewing. A control device forms stitches on an object to be sewn according to sewing data (S3). When the control device moves the needle bar mechanism, hook mechanism, and workpiece to the last needle drop position using the moving mechanism without vertically moving the needle bar when the sewing order moves to the last needle drop position. The bobbin thread is pulled out by relatively moving by a first distance longer than the moving distance (S6). After S6, the control device causes the moving mechanism to move the workpiece by a second distance relative to the needle bar mechanism and hook mechanism to the final needle drop position, and the spring of the bobbin case moves the workpiece to the final needle drop position. The slack of the bobbin thread is absorbed (S7). After S7, the control device drives the needle bar mechanism and hook mechanism to form a stitch at the final needle drop position, and drives the thread cutting mechanism to cut the upper thread and lower thread (S10). . [Selection diagram] Figure 9

Description

The present invention relates to a sewing device.

In a conventional full-rotation hook of a sewing device, a thread crossing slope part is formed in a part of the thread sliding slope surface, through which the needle thread loop crosses from the thread sliding slope surface to the outer surface of the bobbin case. The angle of inclination of the thread crossing inclined portion with respect to the axial direction of the rotational center axis is set to be larger than the inclination angle of the thread sliding inclined surface with respect to the axial direction of the rotational center axis.

JP2009-72520A

In the sewing device described above, the tension of the bobbin thread is too high at the start of sewing and the bobbin thread cannot be pulled out, which may result in sewing defects such as skipped stitches and fake stitches.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sewing device that is capable of forming more stable stitches than conventional ones at the start of sewing.

The sewing device according to claim 1 of the present invention includes a needle bar that extends in the vertical direction and to which a sewing needle can be attached at the lower end, a needle bar mechanism that moves the needle bar up and down, and a needle plate that has a needle hole through which the sewing needle is inserted. a hook mechanism disposed below the throat plate and having a hook for removably attaching a bobbin case having a spring for eliminating slack in the bobbin thread; the hook mechanism and the needle bar mechanism; , a thread cutting mechanism that cuts the upper thread and the bobbin thread below the throat plate, and a control device, the control device comprising: , controlling the needle bar mechanism, the hook mechanism, and the moving mechanism to perform a sewing operation to form a stitch on the sewing object, and to move to the last needle drop position in the sewing order specified by the sewing data. In some cases, the movement distance is longer than the movement distance when the movement mechanism moves the sewing workpiece to the last needle drop position with respect to the needle bar mechanism and the hook mechanism without vertically moving the needle bar. A surplus feed operation that pulls out the bobbin thread from the bobbin held in the bobbin case by relatively moving it by a long first distance; and after the surplus feed operation, the needle bar mechanism and the shuttle mechanism are moved by the moving mechanism. a return feed operation in which the workpiece is moved by a second distance to the final needle drop position, and the slack of the bobbin thread is absorbed by the spring of the bobbin case; After the return feed operation, the needle bar mechanism and the shuttle mechanism are driven to form the stitch at the final needle drop position, and the thread trimming mechanism is driven to cut the upper thread and the lower thread. and a thread cutting operation. The sewing device according to claim 1 allows the bobbin thread to become slack before cutting the thread at the end of sewing, so that when starting sewing after the return feed operation, the bobbin thread that has already been pulled out from the bobbin is used for the first few stitches. can be sewn. Therefore, the sewing device can reliably avoid the situation where the tension of the bobbin thread is too high at the start of sewing and the bobbin thread cannot be pulled out, and it can prevent the stitches caused by the tension of the bobbin thread being too high at the start of sewing. Sewing defects such as skipped stitches and fake stitches can be suitably suppressed.

In the sewing device according to the second aspect of the present invention, the hook is a full-rotation hook. The sewing device according to claim 2 can suitably suppress sewing defects such as skipped stitches and fake stitches that occur due to too high tension of the bobbin thread at the start of sewing when the hook is a full rotation hook. .

In the sewing device according to claim 3, the bobbin case has a groove provided along the outer periphery of the bobbin case, and the spring is exposed on the outer periphery of the bobbin case and the bobbin case is held by the bobbin case. The threading section has a threading section that is movable along the groove section through which the bobbin thread is wound around the thread. The threading section is located at one end, and during the return feed operation, the threading section moves toward the other end of the groove due to the biasing force of the spring. The sewing device according to the third aspect of the present invention has a relatively simple structure of a threading section, and can create slack in the bobbin thread during the return operation.

The bobbin case of the sewing device according to claim 4 includes a tension applying section that applies tension to the lower thread between the threading section and the bobbin, and the tension applying section applies tension to the lower thread. is larger than the tension applied to the bobbin thread by the spring. In the sewing device according to claim 4, when starting the sewing operation again after the return feed operation, for the first few stitches, the tension of the bobbin thread is determined only by the biasing force of the spring, so that the bobbin thread is removed from the bobbin. The tension on the bobbin thread can be reduced compared to when the bobbin thread is pulled out.

In the sewing device according to claim 5, a length obtained by subtracting the moving distance from the first distance is shorter than twice the length of the groove. In the sewing device according to the fifth aspect of the present invention, during the return feed operation, the thread threading section moves from one end of the groove to the other end, thereby making it possible to collect the bobbin thread twice the length of the maximum groove. The sewing device can completely recover the slack of the bobbin thread corresponding to the length obtained by subtracting the moving distance from the first distance, which occurs during the return feed operation, using the spring.

In the sewing device according to a sixth aspect of the present invention, when the sewing operation is started after the return feed operation, the bobbin thread is used to remove slack by the spring during the previous return feed operation, so that two stitches can be stitched from the start of sewing. The seam is formed. In the sewing device according to claim 6, when the sewing operation is started after the return feed operation, two stitches from the start of sewing can be sewn using the bobbin thread to which only the biasing force of the spring is applied. Sewing defects such as skipped stitches and fake stitches caused by too high tension of the bobbin thread can be suitably suppressed.

FIG. 1 is a perspective view of the sewing device 1. FIG. 3 is a perspective view of a needle bar mechanism 6 and a hook mechanism 7. FIG. 3 is a perspective view of a needle bar mechanism 6 and a hook mechanism 7. FIG. 3 is a perspective view of a needle bar mechanism 6 and a hook mechanism 7. FIG. 2 is a perspective view of a bobbin case 200. FIG. 2 is a right side view of the bobbin case 200. FIG. 2 is a rear view of the bobbin case 200. 1 is a block diagram showing the electrical configuration of sewing device 1. FIG. Flowchart of main processing. FIG. 7 is a schematic diagram of a process of sewing the last needle drop point in the main process.

The physical configuration of a sewing device 1 according to an embodiment of the present invention will be described. In the following description, left and right, front and back, and up and down directions indicated by arrows in the drawings will be used. As shown in FIGS. 1 to 4, the sewing device 1 is a gate-shaped sewing device, which includes a bed portion 2, pillar portions 3 and 4, a synchronization mechanism 31 (see FIG. 8), a beam portion 5, a needle bar mechanism 6, a middle It includes a presser mechanism 120, a thread removal mechanism 130, a shuttle mechanism 7, a thread trimming mechanism 110, a holding mechanism 8, a conveyance mechanism 9 (see FIG. 8), a feed mechanism 10 (see FIG. 8), and an operation section 14. By means of the transport mechanism 9 and the feed mechanism 10, the shuttle mechanism 7, the needle bar mechanism 6, and the object to be sewn C move relatively in the horizontal direction.

The bed section 2 includes a base section 21, a first mounting section 22, a second mounting section 76, openings 24 and 25, bellows 26 and 27, a frame 28, a lower rail 29, and a pair of rails. The base 21 has a substantially rectangular parallelepiped shape. The first mounting section 22 is a plate that forms the upper surface of the base 21 and extends parallel to the horizontal surface. The first mounting portion 22 includes an opening 23 extending in the left-right direction. The second mounting section 76 is a rectangular plate disposed in front of the first mounting section 22 and flush with the first mounting section 22 . The opening 24 extends in the front-rear direction near the left end of the first mounting section 22 . The opening 25 extends in the front-rear direction near the right end of the first mounting section 22 . The openings 24 and 25 each extend in a rectangular shape in a plan view between the front end and the rear end of the first mounting section 22, and open upward. Bellows 26, 27 cover openings 24, 25, respectively. A pair of rails are provided below the bellows 26, 27. The pair of rails supports the connecting portions 78 and 79 of the feeding mechanism 10 so as to be movable in the front and rear directions. The frame 28 is a lattice-like structure and supports the base 21 from below. The lower rail 29 extends in the left-right direction below the first mounting portion 22. The lower rail 29 supports the hook mechanism 7 so that it can move laterally. In the bed section 2, a lower belt 94, a lower spline shaft 34, and a hook mechanism 7, which will be described later, are arranged below the first placing section 22.

Each of the pillar parts 3 and 4 has a substantially square prism shape. The pillar portion 3 extends upward at approximately the center of the left end portion of the bed portion 2 in the front-rear direction. The pillar portion 4 extends upward at approximately the center of the right end portion of the bed portion 2 in the front-rear direction. The pillar parts 3 and 4 are separated from each other in the left-right direction with the first mounting part 22 in between. The synchronization mechanism 31 is a mechanism for synchronously driving the needle bar mechanism 6 and the shuttle mechanism 7, and includes a main motor 32 (see FIG. 8), an upper spline shaft 33, a lower spline shaft 34, and a transmission mechanism. The main motor 32 is supported by the pillar section 3. The upper spline shaft 33 and the lower spline shaft 34 extend in the left-right direction between the pillar parts 3 and 4. A transmission mechanism of the synchronization mechanism 31 is housed in the pillar section 3 and transmits the power of the main motor 32 to the upper spline shaft 33 and the lower spline shaft 34. The conveyance mechanism 9 can move the shuttle mechanism 7 and the needle bar mechanism 6 in the left and right directions parallel to the horizontal direction with respect to the workpiece C (see FIG. 10), and is connected to an upper belt 93, a lower belt 94, and an X motor 95, which will be described later. , a transmission mechanism. In the sewing device 1 of this example, a holding mechanism 8 holds a workpiece C to be sewn. The X motor 95 is a pulse motor, and is supported by the pillar section 4. A transmission mechanism of the conveyance mechanism 9 is housed in the pillar section 4 and transmits the power of the X motor 95 to the upper belt 93 and the lower belt 94. The upper belt 93 is fixed to the back surface of the needle bar mechanism 6. The lower belt 94 is fixed to the back of the hook mechanism 7. The shuttle mechanism 7 and the needle bar mechanism 6 move laterally in accordance with the rotation of the X motor 95.

The beam portion 5 is constructed between the pillar portions 3 and 4 and extends in the left-right direction. The beam portion 5 supports the needle bar mechanism 6 on the rear side with respect to the needle bar mechanism 6 so as to be movable in the left and right directions parallel to the horizontal direction. The beam portion 5 includes a housing 51, a bellows 52, and an upper rail 53. The housing 51 extends in the left-right direction from the upper end and rear end of each of the pillar sections 3 and 4. The bellows 52 is installed at the front ends of the pillars 3 and 4, the housing 51, and both left and right ends of the needle bar mechanism 6, which will be described later. The upper rail 53 has a rod shape extending in the left-right direction, and is installed between the pillar parts 3 and 4. The upper rail 53 supports the needle bar mechanism 6 so as to be movable in the left and right direction. The housing 51 covers the upper rail 53 and the upper side and rear side of the upper spline shaft 33 of the synchronization mechanism 31. The bellows 52 covers the front side of the upper rail 53 and the upper spline shaft 33. The bellows 52 expands and contracts in response to the left and right movement of the needle bar mechanism 6.

The needle bar mechanism 6 is provided on the front side of the beam portion 5. The needle bar mechanism 6 includes a housing 60, an upper shaft 61, a transmission mechanism 62, and a needle bar 63, and can move the needle bar 63 up and down. The needle bar 63 extends in the vertical direction, and a sewing needle 65 can be attached to the lower end. The housing 60 is box-shaped and houses the upper shaft 61. The back surface of the casing 60 is connected to the upper belt 93, and the casing 60 is supported by the upper rail 53. The housing 60 is provided with an auxiliary thread tension device 35 and a thread tension device 36 on its entire surface. The thread tension device 36 adjusts the tension applied to the upper thread U held between the pair of thread tension discs. The thread tension device 36 is provided below and to the left of the sub-thread tension device 35. The auxiliary thread tension device 35 adjusts the tension applied to the upper thread U together with the thread tension device 36. The needle bar mechanism 6 can be moved left and right along the upper rail 53 within the beam portion 5 by driving the transport mechanism 9. The upper shaft 61 extends in the left-right direction. The transmission mechanism 62 transmits the power of the upper spline shaft 33 to the upper shaft 61. The needle bar 63 extends in the vertical direction, and a sewing needle 65 can be attached to the lower end. The needle bar 63 is connected to the upper shaft 61 and moves up and down by the drive of the main motor 32.

The intermediate presser mechanism 120 includes an intermediate presser bar 69, an intermediate presser motor 68, and a transmission mechanism 121. In FIG. 2, illustration of the intermediate presser motor 68 and the transmission mechanism 121 is omitted. The intermediate presser bar 69 has an intermediate presser 64 at its lower end, and extends in the vertical direction parallel to the needle bar 63. The intermediate presser foot 64 has a through hole through which the sewing needle 65 passes according to the vertical movement of the needle bar 63, and presses the workpiece C intermittently from above. The intermediate presser motor 68 is a pulse motor fixed to the upper surface of the housing 60. The intermediate presser motor 68 moves the intermediate presser bar 69 up and down, and moves the intermediate presser 64 up and down between a contact position where it contacts the workpiece C and a separated position above the contact position. The transmission mechanism 121 is connected to the output shaft of the intermediate presser motor 68 and the intermediate presser rod 69, and transmits the rotation of the output shaft of the intermediate presser motor 68 to the intermediate presser rod 69.

The thread removing mechanism 130 performs thread removing to move the end of the upper thread U (see FIG. 10) cut by the thread cutting mechanism 110 above the intermediate presser foot 64. The thread removing mechanism 130 includes an air cylinder 131, a link 134, a thread removing shaft 135, and a thread removing lever 136. The thread removal mechanism 130 is fixed to the back surface of the housing 60 of the sewing device 1. Air cylinder 131 sucks the output shaft. The link 134 is connected to the output shaft of the air cylinder 131 and the yarn removal shaft 135, and the yarn removal shaft 135 rotates via the link 134 as the output shaft moves. The thread removing lever 136 is fixed to the thread removing shaft 135 and swings as the thread removing shaft 135 rotates. The tip of the thread removal lever 136 moves from the standby position to the thread removal position when the air cylinder 131 sucks the output shaft. As shown in FIGS. 2 and 3, in the standby position, the tip of the thread removing lever 136 is on the right side of the thread removing shaft 135. The thread wiping position is such that the tip of the thread wiping lever 136 is below the thread wiping shaft 135. In the process of moving from the standby position to the thread wiping position, the tip of the thread wiping lever 136 passes between the lower end of the sewing needle 65 and the upper end of the cylindrical portion of the intermediate presser 64 in the vertical position, and captures the upper thread U. When the suction by the air cylinder 131 stops, the tip of the thread removal lever 136 moves to the standby position due to the biasing force of the spring. Therefore, the thread removal lever 136 can move the upper thread U above the intermediate presser foot 64. The lower thread L remains on the back side of the workpiece C (the side facing the throat plate 74).

The hook mechanism 7 is disposed below the needle bar mechanism 6 and the needle plate 74, and is disposed inside the bed portion 2. The hook mechanism 7 includes a housing 70, a lower shaft 71, a transmission mechanism 72, and a hook 73. The housing 70 is box-shaped and includes a throat plate 74 at the upper left end. The throat plate 74 has a needle hole 75 through which the sewing needle 65 can be inserted. The needle hole 75 is located below the needle bar 63. As shown in FIG. 2, the back surface of the housing 70 is connected to the lower belt 94. The lower spline shaft 34 is inserted into the housing 70 . The housing 70 is supported by the lower rail 29. The shuttle mechanism 7 is driven by the transport mechanism 9 and can move left and right along the lower rail 29 in synchronization with the needle bar mechanism 6. The transmission mechanism 72 transmits the power of the lower spline shaft 34 to the lower shaft 71. The hook 73 is connected to the lower shaft 71 and rotated by the main motor 32 in synchronization with the vertical movement of the needle bar 63. The hook 73 holds a bobbin on which the bobbin thread L is wound, and a bobbin case 200 having a spring 203 for eliminating slack in the bobbin thread L is removably attached thereto. The hook 73 is a fully rotating vertical hook, and includes an outer hook 88, an inner hook 77, and an inner hook stopper (not shown). The outer hook 80 is provided with a tip (not shown). The outer hook 80 rotates clockwise in front view in synchronization with the vertical movement of the sewing needle 65. The inner hook 77 is fitted into the outer hook 80. The inner hook 77 is rotatable relative to the outer hook 80. The bobbin case 200 is fixed inside the inner hook 77. The bobbin case 200 stores a bobbin (not shown) wound with a bobbin thread.

The bobbin case 200 will be described with reference to FIGS. 5 to 7. The main body portion 201 of the bobbin case 200 includes an outer peripheral portion 207, a left side portion 208, a circular hole portion 210, a locking lever 209, a spring 203, and a tension applying portion 211. The outer circumferential portion 207 has a cylindrical shape that stores a bobbin. A groove portion 202 extending in the circumferential direction is formed in the outer peripheral portion 207 . The length of the groove portion 202 in the circumferential direction is, for example, 5 to 20 mm. The left side portion 208 closes the left end portion of the outer peripheral portion 207. The circular hole portion 210 is a circular hole portion formed at the center of the left side portion 208 into which the support shaft of the inner hook 77 of the hook mechanism 7 is inserted. The locking lever 209 locks a circumferential groove formed at the tip of the spindle of the inner hook 77 into which the circular hole portion 210 is inserted, thereby preventing the bobbin case 200 from coming off the inner hook 77 .

The spring 203 applies tension to the lower thread L that is paid out from the bobbin. The spring 203 is a spring curved to follow the inner peripheral surface of the outer peripheral part 207, and one end of the spring 203 is a threading part 204 processed into a loop shape. The diameter of the threading portion 204 is, for example, 3 to 5 mm. The threading portion 204 is exposed from the groove portion 202 to the outside of the outer peripheral portion 207, that is, to the outer periphery of the bobbin case 200. The other end portion 214 of the spring 203 is fixed to the left side portion 208 by a screw 205. The threading section 204 passes the lower thread L wound around the bobbin held by the bobbin case 200, and can move along the groove section 202. The outer circumferential portion 207 is provided with an outlet 206 for feeding the lower thread L. The tension applying section 211 is provided below the outlet 206 and is a plate spring. The lower end of the tension applying portion 211 is fixed to the lower end of the outer peripheral portion 207 by a pair of screws 213 . A U-shaped notch 212 is formed at the upper end of the tension applying section 211 . The tension applying section 211 applies tension due to frictional force to the lower thread L between the threading section 204 and the bobbin by passing the lower thread L through the gap between the outer peripheral section 207 and the tension applying section 211 . The upper end of the tension applying section 211 is located above the lower end of the groove section 202. As shown in FIG. 10, the bobbin thread L let out from the bobbin is passed through the threading section 204 of the spring 203, and the biasing force of the spring 203 is applied depending on the position of the threading section 204. When the threading section 204 is located at the lower end of the groove section 202, the spring 203 does not apply a biasing force to the bobbin thread L. When the threading section 204 is separated from the lower end of the groove 202 and located at the upper end of the groove 202, the spring 203 applies a biasing force to the lower thread L. The tension applied to the lower thread L by the tension applying section 211 is greater than the tension applied to the lower thread L by the spring 203. The lower thread L is guided from the threading section 204 to the needle hole 75 of the needle plate 74.

As shown in FIGS. 3 and 4, the thread cutting mechanism 110 cuts the upper thread U and the lower thread L below the throat plate 74. The thread cutting mechanism 110 includes a fixed blade 111, a movable blade 112, a thread cutting motor 113, and a link mechanism 114. A part of the link mechanism 114 and the thread trimming motor 113 are provided outside the housing 70. The thread cutting mechanism 110 moves the movable blade 112 via the link mechanism 114 to cut the upper thread U and the lower thread L. The fixed blade 111 is fixed to the lower side of the throat plate 74. The movable blade 112 is provided so as to be horizontally rotatable with respect to the fixed blade 111. The movable blade 112 has a standby position located away from the fixed blade 111, a cutting position where it intersects with the fixed blade 111 to cut the upper thread U and the lower thread L, and a cutting position on the opposite side of the cutting position from the standby position. Can be moved between the maximum movable position. The thread cutting motor 113 is a pulse motor and drives the movable blade 112. The link mechanism 114 is connected to the output shaft of the thread trimming motor 113 and the movable blade 112, and transmits rotation of the output shaft to the movable blade 112. When the movable blade 112 moves from the standby position to the maximum movable position, the tip 116 of the movable blade 112 enters the loop of the upper thread U and captures the upper thread U. When the movable blade 112 rotates back from the maximum movable position to the standby position, the blade portion of the movable blade 112 and the blade portion of the fixed blade 111 separate the lower thread L and the upper thread at the cutting position between the maximum movable position and the standby position. Among the loops of thread U, the needle thread U on the side to be sewn C is cut at the same time.

The feed mechanism 10 can move the holding mechanism 8 holding the workpiece C back and forth relative to the needle bar mechanism 6 and hook mechanism 7. The feeding mechanism 10 includes connecting portions 78 and 79. The lower left end of the connecting portion 78 is placed on the rail in the opening 24 of the bed portion 2. The lower right end of the connecting portion 79 is placed on the rail at the opening 25 of the bed portion 2 . The connecting parts 78 and 79 connect with the holding mechanism 8. The holding mechanism 8 can hold the object C to be sewn. The holding mechanism 8 has an upper frame 81, a lower frame 82, and air cylinders 83 and 84. The upper frame 81 and the lower frame 82 are rectangular frames in a plan view, and hold the workpiece C therebetween. The upper frame 81 opens and closes vertically relative to the lower frame 82 using air cylinders 83 and 84 as driving sources.

The feeding mechanism 10 includes a Y motor 101 (see FIG. 8), a transmission mechanism, and a pair of belts below the first mounting section 22. Y motor 101 is a pulse motor. The transmission mechanism of the feed mechanism 10 transmits the Y motor 101 to a pair of belts fixed to connecting parts 78 and 79. The holding mechanism 8 moves back and forth along the pair of rails of the bed section 2 in accordance with the rotation of the Y motor 101.

The operating section 14 is supported at the left end of the second mounting section 76 . The operation section 14 includes a switch group 12 and a display section 13. The switch group 12 inputs various instructions according to operations by the operator. The display unit 13 is a liquid crystal display and can display various images.

The electrical configuration of the sewing device 1 will be described with reference to FIG. 8. The control unit 15 of the sewing device 1 includes a CPU 16, a ROM 17, a RAM 18, a storage device 19, an input/output interface (I/O) 20, drive circuits 41 to 48, and the like. The CPU 16 centrally controls the operation of the sewing device 1. The ROM 17 stores in advance programs and the like for executing various processes. The RAM 18 temporarily stores various information generated during execution of various processes. The storage device 19 is non-volatile and stores various setting values.

Each drive circuit 41 to 48, encoders 55 to 59, and switch group 12 are connected to I/O 20. The drive circuit 41 is connected to the main motor 32 of the synchronization mechanism 31 and drives the main motor 32 based on control commands from the CPU 16 . The drive circuit 42 is connected to the X motor 95 of the transport mechanism 9, and drives the X motor 95 in response to a control command from the CPU 16. The drive circuit 43 is connected to the Y motor 101 of the feed mechanism 10 and drives the Y motor 101 in response to a control command from the CPU 16. The drive circuit 43 is connected to the air cylinders 83 and 84 of the holding mechanism 8, and drives the air cylinders 83 and 84 according to control commands from the CPU 16. The drive circuit 45 is connected to the air cylinder 131 and drives the air cylinder 131 in response to a control command from the CPU 16. The drive circuit 46 is connected to the intermediate presser motor 68, and drives the intermediate presser motor 68 in response to a control command from the CPU 16. The drive circuit 47 is connected to the thread trimming motor 113 and drives the thread trimming motor 113 in response to a control command from the CPU 16 . The drive circuit 48 is connected to the display section 13 and displays various information on the display section 13 under control commands from the CPU 16.

The encoder 55 detects the rotational position and rotational speed of the output shaft of the main motor 32, and inputs the detection results to the I/O 20. The detection result of encoder 55 indicates the vertical position of needle bar 63 and sewing needle 65. The encoder 56 detects the rotational direction, rotational position, and rotational speed of the output shaft of the X motor 95, and inputs the detection results to the I/O 20. The detection result of the encoder 56 indicates the left and right positions of the needle bar mechanism 6 and hook mechanism 7. The encoder 57 detects the rotational direction, rotational position, and rotational speed of the output shaft of the Y motor 101, and inputs the detection results to the I/O 20. The detection result of the encoder 57 indicates the front and rear positions of the holding mechanism 8. The encoder 58 detects the rotational direction, rotational position, and rotational speed of the output shaft of the intermediate presser motor 68, and inputs the detection results to the I/O 20. The detection result of the encoder 58 indicates the vertical position of the intermediate presser 64. The encoder 59 detects the rotational direction, rotational position, and rotational speed of the output shaft of the thread trimming motor 113, and inputs the detection results to the I/O 20. The detection result of the encoder 59 indicates the rotational position of the movable blade 112. The switch group 12 detects various instructions and inputs the detection results to the I/O 20.

The main process will be described with reference to Figures 9 and 10. For convenience, the sewing operation will be described in Figure 10 in the forward and backward directions, but the sewing operation may proceed in a different direction E. The main process is a process in which the sewing device 1 forms a stitch on the workpiece C in accordance with the sewing data, and then the upper thread U and the lower thread L are cut by the thread cutting mechanism 110. The main sewing process is started when the operator operates the switch group 12 from the menu displayed on the display unit 13 to specify the start of the process. The CPU 16 reads the program for the main process from the ROM 17 into the RAM 18 and executes the main process. The sewing data includes coordinate data indicating the position of the needle drop point within the sewing area of the holding mechanism 8 for each stitch, and is stored in advance in the storage device 19.

The CPU 16 refers to the storage device 19 and obtains sewing data (S1). The CPU 16 determines whether a sewing start instruction has been detected (S2). The operator operates the switch group 12 to input a sewing start instruction. When the sewing start instruction is not detected (S2: NO), the CPU 16 waits in S2 until the sewing start instruction is detected. When the sewing start instruction is detected (S2: YES), the CPU 16 reads the coordinate data of the sewing data acquired in S2 in the sewing order, drives the conveying mechanism 9, the feeding mechanism 10, and the synchronizing mechanism 31 according to the coordinate data, and drives the holding mechanism 8. The process of sewing within the sewing area is started (S3). Thereby, the CPU 16 controls the needle bar mechanism 6, hook mechanism 7, conveyance mechanism 9, and feed mechanism 10 in accordance with the sewing data to perform a sewing operation to form stitches on the object to be sewn C (S3).

The CPU 16 determines whether the next coordinate data is that of the final needle (S4). The last needle is the last needle drop point in the sewing order. When the next coordinate data is not the coordinate data of the final needle (S4: NO), the CPU 16 continues the sewing operation until the next coordinate data becomes the coordinate data of the final needle. do. When the next coordinate data is the coordinate data of the final needle (S4: YES), the CPU 16 stops driving the synchronizing mechanism 31 and stops the vertical movement of the needle bar 63 (S5). As shown in FIG. 10(A), the CPU 16 calculates the moving distance MD when moving the sewing workpiece C to the final needle drop position P with respect to the needle bar mechanism 6 and shuttle mechanism 7 using the transport mechanism 9 and the feed mechanism 10. A surplus feed operation is performed in which the bobbin thread L is pulled out from the bobbin held in the bobbin case 200 by relatively moving surplus by a first distance D1 longer than the above (S6). The movement distance MD is the length of one stitch, and is the length from the needle drop position F immediately before the final stitch to the needle drop position P of the final stitch. The CPU 16 of this embodiment moves the needle bar 63 relative to the object C to be sewn to a point Q that is away from the needle drop position P indicated by the coordinate data of the final needle in the direction of stitch movement E. The direction of movement E is represented by a vector from the needle drop position F immediately before the final needle in the sewing order to the needle drop position P of the final needle. The length obtained by subtracting the movement distance MD from the first distance D1 is shorter than twice the length of the groove portion 202.

As shown in FIG. 10(B), after the surplus feed operation, the CPU 16 moves the workpiece C by a second distance D2 relative to the needle bar mechanism 6 and hook mechanism 7 using the conveyance mechanism 9 and the feed mechanism 10. This moves the needle to the final needle drop position P (S7). The CPU 16 moves the needle bar 63 relative to the object C by a second distance D2 from the point Q in the direction R opposite to the direction of movement E of S6. The second distance D2 is shorter than the first distance D1. In this embodiment, the length obtained by subtracting the movement distance MD from the first distance D1 is the second distance D2. Through the process of S7, the workpiece C is moved relative to the needle bar 63 to the needle drop position P indicated by the coordinate data of the final needle. Through the process of S7, each of the upper thread U and the lower thread L is loosened by a length obtained by subtracting the movement distance MD from the first distance D1, that is, the second distance D2. As shown in FIG. 10(C), the slack of the bobbin thread L is absorbed by the spring 203 of the bobbin case 200. Specifically, the loosening of the bobbin thread L is eliminated by moving the threading section 204 of the bobbin case 200 from the upper end of the groove section 202 to the lower end. The slack in the upper thread U is eliminated by moving the thread take-up spring of the thread tension device 36.

The CPU 16 resumes driving the synchronizing mechanism 31 and resumes the vertical movement of the needle bar 63 (S8). The CPU 16 determines whether or not it is time to trim the thread based on the detection result of the encoder 55 (S9). When it is not time to trim the thread (S9: NO), the CPU 16 waits in S9 until it is time to trim the thread. When it is time to trim the thread (S9: YES), the CPU 16 drives the needle bar mechanism 6 and the hook mechanism 7 after the return feed operation to form a stitch at the final needle drop position P, while the thread trimming mechanism 110 to perform a thread cutting operation of cutting the upper thread U and lower thread L. Specifically, the CPU 16 drives the thread cutting motor 113 to move the movable blade 112 of the thread cutting mechanism 110 to the cutting position, and cuts the upper thread U and lower thread L (S10). The CPU 16 drives the air cylinder 131 at a predetermined timing to move the thread removing lever 136 of the thread removing mechanism 130, and moves the end of the needle thread U cut by the thread cutting mechanism 110 above the cylindrical portion of the intermediate presser foot 64. You may also perform thread removal. The CPU 16 stops driving the transport mechanism 9, the feed mechanism 10, and the synchronization mechanism 31 at the sewing end time based on the detection result of the encoder 55, and ends the sewing (S11). The CPU 16 then ends the main processing.

When starting the sewing operation again after the return feed operation, the bobbin thread L is not pulled out from the bobbin for the first few stitches. When the sewing operation is started again after the return feed operation, the first few stitches are sewn using the bobbin thread L that has been loosened by the spring 203. In the sewing device 1 of this embodiment, when the sewing operation is started after the return feed operation, the bobbin thread L that has been loosened by the spring 203 during the previous return operation is used to perform two stitches from the start of sewing. Eyes are formed (S3). The length of the stitch formed by the bobbin thread L that has been loosened may range from 5 to 20 mm, for example.

In the above embodiment, the sewing device 1, the needle bar mechanism 6, the hook mechanism 7, the CPU 16, the needle bar 63, the hook 73, the throat plate 74, the thread trimming mechanism 110, the bobbin case 200, the groove portion 202, the spring 203, the threading portion 204 , and tension applying section 211 respectively include the sewing device, needle bar mechanism, hook mechanism, control device, needle bar, hook, needle plate, thread cutting mechanism, bobbin case, groove section, spring, threading section, and tension section of the present invention. This is an example of a giving part. The transport mechanism 9 and the feed mechanism 10 are examples of the moving mechanism of the present invention.

The sewing device 1 of the embodiment described above includes a needle bar 63, a needle bar mechanism 6, a throat plate 74, a hook mechanism 7, a conveyance mechanism 9, a feed mechanism 10, a thread trimming mechanism 110, and a CPU 16. The needle bar 63 extends in the vertical direction, and a sewing needle 65 can be attached to the lower end. The needle bar mechanism 6 moves the needle bar 63 up and down. Throat plate 74 has a needle hole 75 through which sewing needle 65 is inserted. The hook mechanism 7 has a hook 73 that is disposed below the throat plate 74 and removably mounts a bobbin case 200 having a spring 203 for eliminating slack in the bobbin thread L. The conveyance mechanism 9 and the feed mechanism 10 relatively move the shuttle mechanism 7, the needle bar mechanism 6, and the object to be sewn C in the horizontal direction. The thread cutting mechanism 110 cuts the upper thread U and the lower thread L below the throat plate 74. The CPU 16 controls the needle bar mechanism 6, hook mechanism 7, transport mechanism 9, and feed mechanism 10 in accordance with the sewing data to perform a sewing operation to form stitches on the object C to be sewn (S3). When the sewing order designated by the sewing data is moved to the last needle drop position P, the CPU 16 does not move the needle bar 63 up and down, and the conveyance mechanism 9 and the feed mechanism 10 move the needle bar mechanism 6 and the hook mechanism 7. The bobbin thread is removed from the bobbin held in the bobbin case 200 by relatively moving the workpiece C by a first distance D1, which is longer than the movement distance MD when moving the workpiece C to the last needle drop position P in the sewing order. A surplus feed operation is performed to draw out L (S6). After the surplus feed operation, the CPU 16 moves the workpiece C by a second distance D2 relative to the needle bar mechanism 6 and hook mechanism 7 using the conveyance mechanism 9 and the feed mechanism 10 to determine the final needle drop position. P, and a return operation is performed in which the slack of the bobbin thread L is absorbed by the spring 203 of the bobbin case 200 (S7). After the return feed operation, the CPU 16 drives the needle bar mechanism 6 and hook mechanism 7 to form a stitch at the final needle drop position P, and drives the thread trimming mechanism 110 to cut the upper thread U and lower thread L. A thread cutting operation is performed to cut the thread (S10). When the sewing operation is started again after the return feed operation, the first few stitches are sewn using the bobbin thread L that has been loosened by the spring 203. By slackening the bobbin thread L before thread cutting at the end of sewing, the sewing device 1 uses the bobbin thread L that has already been pulled out from the bobbin for the first few stitches when starting sewing after the return feed operation. It can be sewn by hand. Therefore, the sewing device 1 can reliably avoid the situation where the tension of the bobbin thread L is too high at the start of sewing and the bobbin thread L cannot be pulled out, and can prevent the situation caused by the tension of the bobbin thread L being too high at the start of sewing. It is possible to suitably suppress sewing defects such as skipped stitches and fake stitches.

The hook 73 of the sewing device 1 is a full-rotation hook. When the hook 73 is a full-rotation hook, the sewing device 1 can suitably suppress sewing defects such as skipped stitches and fake stitches caused by too high tension of the bobbin thread L at the start of sewing.

The bobbin case 200 of the sewing device 1 has a groove 202 provided along the outer periphery of the bobbin case 200. The spring 203 has a threading section 204 that is exposed on the outer periphery of the bobbin case 200 and is movable along the groove section 202 through which the lower thread L wound around the bobbin held by the bobbin case 200 is passed. During the surplus feed operation, the threading section 204 is located on the upper end side of the groove section 202 against the biasing force of the spring 203. During the return feed operation, the threading section 204 moves toward the lower end of the groove section 202 due to the biasing force of the spring 203. The sewing device 1 has a relatively simple configuration including the threading section 204, and can cause the bobbin thread L to become slack during the return operation.

The bobbin case 200 of the sewing device 1 is equipped with a tension applying section 211 that applies tension to the lower thread L between the threading section 204 and the bobbin, and the tension applied to the lower thread L by the tension applying section 211 is greater than the tension applied to the lower thread L by the spring 203. When sewing is resumed after a return feed operation, the lower thread L is not pulled out from the bobbin for the first few stitches. When sewing is resumed after a return feed operation, the tension of the lower thread L is determined only by the biasing force of the spring 203, so the tension of the lower thread L can be reduced compared to when the lower thread L is pulled out from the bobbin.

The length obtained by subtracting the moving distance MD from the first distance D1 of the sewing device 1 is shorter than twice the length of the groove portion 202. The sewing device 1 can collect the bobbin thread L twice the length of the maximum groove 202 by moving the threading section 204 from the upper end to the lower end of the groove 202 during the return feed operation. In the sewing device 1, the spring 203 can completely recover the slack of the bobbin thread L corresponding to the length obtained by subtracting the movement distance MD from the first distance D1, which occurs during the return feed operation.

In the sewing device 1, when the sewing operation is started after the return feed operation, two stitches are formed from the start of sewing using the bobbin thread L that was loosened by the spring 203 during the previous return operation. (S3). When the sewing operation is started after the return feed operation, the sewing device 1 can sew two stitches from the start of sewing using the bobbin thread L to which the biasing force of the spring 203 is applied, and the lower thread at the start of sewing It is possible to suitably suppress sewing defects such as skipped stitches and fake stitches that occur due to too high tension of L.

The sewing device of the present invention can be modified in various ways other than the embodiments described above. The type of sewing device 1 may be changed as appropriate, such as various industrial sewing machines or household sewing machines. The hook 73 of the sewing device 1 may be a hook other than a full-rotation vertical hook, for example, a horizontal hook.

The program including instructions for executing the processing of the sewing device 1 may be stored in the storage device of the sewing device 1 until the program is executed by the sewing device 1. Therefore, the program acquisition method, acquisition route, and device that stores the program may be changed as appropriate. For example, the program executed by the CPU 16 of the sewing device 1 may be received from another device via a cable or wireless communication, and may be stored in a storage device such as a flash memory. Other devices include, for example, a PC and a server connected via a network.

A part or all of the processing executed by the sewing device 1 may be executed by an electronic device (for example, an ASIC) other than the CPU 16. The processing executed by the sewing device 1 may be distributed by a plurality of electronic devices (for example, a plurality of CPUs). The order of each step of the process executed by the sewing device 1 can be changed, steps can be omitted, and additions can be made as necessary. The scope of the present invention also includes a mode in which an operating system (OS) or the like running on the sewing device 1 performs part or all of each process based on instructions from the CPU 16. For example, the following changes may be made to the above embodiment as appropriate.

The sewing device 1 may perform the extra feed operation or the return feed operation by driving only either the conveyance mechanism 9 or the feed mechanism 10. Furthermore, the configurations of the transport mechanism 9 and the sending mechanism 10 are not limited to the above embodiments, and may be any configuration that allows relative movement. For example, the sewing device 1 may use a mechanism that moves the workpiece C in the left-right direction instead of the conveyance mechanism 9 that moves the hook mechanism 7 and the needle bar mechanism 6 in the left-right direction. Furthermore, the sewing device 1 may include only either the transport mechanism 9 or the feed mechanism 10. Further, the sewing device 1 may be one in which the hook mechanism 7, the needle bar mechanism 6, and the object to be sewn C are moved relative to each other only in one horizontal direction.

Instead of the process of moving the workpiece C to a position Q away from the needle drop position P of the final needle in the direction of movement E, the CPU 16 moves the workpiece C to the needle bar mechanism 6 and hook mechanism 7 with the sewing order of the final needle. After relatively moving in any direction from the previous needle drop position F by a first distance D1 that is longer than the moving distance MD (S6), the needle moves a second distance D2 to reach the needle drop position P of the final needle. It may be moved (S7). In this case, the moving direction of S7 does not have to be opposite to the moving direction of S6. In this case, when the moving direction of S6 is directed back to the traveling direction E, the second distance D2 becomes longer than the first distance D1. If the second distance D2 becomes longer than the first distance D1, the slack bobbin thread L that was once collected by the spring will be pulled out again when moving to the needle drop position of the final needle. However, since the first distance D1 moves a distance longer than the movement distance MD, the slack of the bobbin thread L collected by the spring 203 is not completely pulled out, and a length corresponding to the long distance is left. The needle drop position P of the final needle is reached. Therefore, this modification also provides the same effects as the above embodiment. The spring 203 may be a wire spring or a plate spring. The configuration of the threading section 204 may be changed as appropriate. For example, the threading section 204 may be bent into an inverted U shape instead of a loop shape. The formation position and shape of the groove portion 202 may be changed as appropriate. The number and length of stitches sewn with the bobbin thread L that has been loosened by the spring 203 during the previous return feed operation may be changed as appropriate.

1: Sewing device 6: Needle bar mechanism 7: Hook mechanism 9: Conveyance mechanism 10: Feed mechanism 16: CPU
63 : Needle bar 73 : Hook 74 : Throat plate 110 : Thread cutting mechanism 200 : Bobbin case 202 : Groove part 203 : Spring 204 : Threading part 211 : Tension applying part 203 : Spring C : Workpiece D1 : First distance D2 :Second distance L :Bobbin thread MD :Traveling distance

Claims (6)

a needle bar that extends in the vertical direction and to which a sewing needle can be attached at the lower end;
a needle bar mechanism that moves the needle bar up and down;
a needle plate having a needle hole through which the sewing needle is inserted;
a hook mechanism disposed below the throat plate and having a hook for removably mounting a bobbin case having a spring for eliminating slack in the bobbin thread;
a moving mechanism that relatively moves the hook mechanism, the needle bar mechanism, and the workpiece in a horizontal direction;
a thread cutting mechanism that cuts the upper thread and the lower thread below the throat plate;
A sewing device comprising a control device,
The control device includes:
a sewing operation of forming stitches on the object to be sewn by controlling the needle bar mechanism, the shuttle mechanism, and the moving mechanism according to sewing data;
When moving to the last needle drop position in the sewing order specified by the sewing data, the needle bar is not moved up and down, and the movement mechanism moves the object to be sewn relative to the needle bar mechanism and the shuttle mechanism. a redundant feeding operation for drawing out the bobbin thread from the bobbin held in the bobbin case by relatively moving the bobbin thread by a first distance longer than the moving distance when moving to the final needle drop position;
After the surplus feed operation, the movement mechanism moves the workpiece by a second distance relative to the needle bar mechanism and the shuttle mechanism to move it to the last needle drop position, and a return feed operation in which the spring of the case absorbs the slack of the bobbin thread;
After the return feed operation, the needle bar mechanism and the hook mechanism are driven to form the stitch at the last needle drop position, and the thread trimming mechanism is driven to remove the upper thread and the lower thread. A sewing device characterized in that it performs a thread cutting operation. The sewing device according to claim 1, wherein the hook is a full-rotation hook. The bobbin case has a groove provided along the outer periphery of the bobbin case,
The spring has a threading part that is exposed on the outer periphery of the bobbin case and is movable along the groove to pass the lower thread wound around the bobbin held by the bobbin case.
During the surplus feed operation, the threading section is located on one end side of the groove section against the biasing force of the spring, and during the return feeding operation, the threading section is positioned against the biasing force of the spring. The sewing device according to claim 2, wherein the sewing device moves toward the other end of the groove. The bobbin case includes a tension applying section that applies tension to the bobbin thread between the threading section and the bobbin,
The sewing device according to claim 3, wherein the tension applied to the lower thread by the tension applying section is greater than the tension applied to the lower thread by the spring. 5. The sewing device according to claim 3, wherein a length obtained by subtracting the moving distance from the first distance is shorter than twice the length of the groove. When the sewing operation is started after the return feed operation, the two stitches from the start of sewing are formed by the bobbin thread that was loosened by the spring during the previous return operation. The sewing device according to any one of claims 1 to 4, characterized in that:

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