sewing machine

Abstract

To smoothly sew up to the end of an item to be sewn. [Solution] The system comprises an end detection device 60 that detects the side edges in the left-right direction for each of the upper and lower sewn objects C1, C2 upstream of the needle drop position P in the sewing direction F, upper and lower lateral feed mechanisms 40, 50 that move each of the sewn objects C1, C2 left-right using rollers 41, 51 further upstream, and upper and lower differential feed mechanisms 20, 30 that can feed each of the sewn objects C1, C2 by setting different feed amounts in the sewing direction on the left and right of the needle drop position.For each of the sewn objects C1, C2, while the rollers of the lateral feed mechanism are in contact with the sewn object, the lateral feed mechanism guides the sewn object C1, C2 left-right to maintain a constant seam allowance, and when the rollers disengage from the sewn objects C1, C2, the differential feed mechanism guides the sewn object C1, C2 left-right by differential feed to maintain a constant seam allowance.A control device 90 is provided that controls the system.

Description

[Technical Field]

[0001] The present invention relates to a sewing machine for sewing together a side edge of an upper workpiece and a side edge of a lower workpiece. [Background technology]

[0002] Conventional sewing machines sew by adjusting the positions of the side edges of the upper and lower sewing objects to the appropriate positions using a lateral feed mechanism that uses rollers to feed the objects in a direction perpendicular to the feed direction (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-085919 Summary of the Invention [Problem to be solved by the invention]

[0004] The conventional sewing machine described above is provided with a detection device that detects the upper and lower side edges of the workpiece in a direction perpendicular to the sewing direction, upstream of the needle drop position in the sewing direction, and further provided with a lateral feed mechanism upstream of the sewing direction, and the operation of the upper and lower lateral feed mechanisms is controlled based on the detection by the detection device. In the above arrangement, once the end of the upper or lower sewn material passes through the lateral feed mechanism, no further lateral feed occurs. Furthermore, once the end of the upper or lower sewn material passes through the detection device, the side edge of the upper or lower sewn material is no longer detected. This can make it difficult to precisely sew together the side edges of the end of the upper and lower sewn material.

[0005] In particular, when the side edge is significantly curved near the end of the upper or lower sewn material, the rollers of the lateral feed mechanism may deviate from the side edge of the upper or lower sewn material before the end passes, and in such cases, it may be difficult to precisely sew the side edges of the upper and lower sewn material together at the end.

[0006] An object of the present invention is to sew together the side edges of upper and lower materials in a satisfactory manner. [Means for solving the problem]

[0007] The present invention relates to a sewing machine, an edge detection device that detects the position of each side edge in the left and right direction upstream of the needle drop position in the sewing direction for each of the upper and lower sewing objects to be sewn together; a lower and upper lateral feed mechanism for moving each of the lower and upper sewn objects in the left and right direction by rollers, the lower and upper lateral feed mechanisms being located upstream of the end detection device in the sewing direction; lower and upper differential feed mechanisms that can feed the lower and upper sewing objects by different amounts of feed in the sewing direction on the left and right sides of the needle drop position; Equipped with For each of the lower and upper sewing materials, While the roller of the lateral feed mechanism is in contact with the sewing material, the lateral feed mechanism guides the sewing material in the left-right direction so as to maintain a constant seam allowance, When the roller of the lateral feed mechanism comes off the sewing material, the differential feed mechanism guides the sewing material in the left and right directions by the differential feed so as to maintain a constant seam allowance. The apparatus is characterized by including a control device that controls the lower and upper lateral feed mechanisms and the lower and upper differential feed mechanisms. [Effects of the Invention]

[0008] The sewing machine of the present invention, with the above-described configuration, is capable of sewing together the upper and lower sewing materials well to the end portions thereof. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a left side view of a sewing machine according to an embodiment of the present invention; [Figure 2] 1 is a plan view showing an example of an upper cloth and a lower cloth which are objects to be sewn by a sewing machine; [Figure 3] FIG. 10 is a left side view showing the configuration around the needle drop position. [Figure 4] FIG. 4 is a perspective view showing the same configuration as FIG. 3. [Figure 5] FIG. 2 is a plan view of the edge detection device. [Figure 6] FIG. 2 is a horizontal cross-sectional view illustrating a lower traverse mechanism and an upper traverse mechanism. [Figure 7] FIG. 2 is a block diagram showing a control system of the sewing machine. [Figure 8] 10 is a display example of a setting screen for setting the left and right differential feed amounts of the lower feed mechanism and the upper feed mechanism. [Figure 9] FIG. 10 is a plan view of the needle plate showing the feeding state of the sewing material under automatic feed control. [Figure 10] 10 is a plan view of the needle plate showing the feeding state of the sewing workpiece under automatic feed control, following FIG. 9; FIG. [Figure 11] 11 is a plan view of the needle plate showing the feeding state of the sewing workpiece under automatic feed control, following FIG. 10. FIG. [Figure 12] 10 is a diagram showing the relationship between the integrated value of the lateral induced operation amount of the traverse motor of the traverse mechanism and the elapsed time during the state transitions of "normal feed state," "deviation state," and "final state." FIG. [Figure 13] 10 is a plan view showing a sewing section in a "normal feed state," a sewing section in a "deviation state," and a sewing section in a "final state" of a stitch formed on a side edge of an upper cloth. FIG. [Figure 14] 10 is a flowchart of automatic feed control executed by the control device. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Overall configuration of the embodiment] Hereinafter, embodiments of the present invention will be described in detail. FIG. 1 shows a left side view of a sewing machine 100 according to an embodiment of the invention. Hereinafter, the downstream side of the sewing direction of the sewn object will be referred to as the "front," the upstream side of the sewing direction will be referred to as the "rear," the left-hand side when facing forward will be referred to as the "left," the right-hand side will be referred to as the "right," the vertically upward direction will be referred to as the "upper," and the vertically downward direction will be referred to as the "lower." The front-to-rear direction, left-to-right direction, and up-to-down direction are perpendicular to each other. In the following description, it is assumed that the sewing machine 100 is installed on a horizontal surface, and the front-to-back and left-to-right directions are horizontal.

[0011] The sewing machine 100 is a sewing machine for sewing together a right side edge C11 of an upper cloth C1, which is the upper sewing material shown in FIG. 2, and a right side edge C21 of a lower cloth C2, which is the lower sewing material. In the following description, the upper and lower sewing materials may be sheet-like and are not limited to cloth, but for convenience, the upper sewing material will be referred to as upper cloth C1 and the lower sewing material will be referred to as lower cloth C2.

[0012] As an example of a sewing machine 100 according to an embodiment of the present invention, a lock stitch sewing machine equipped with left and right differential feed and side feed functions will be described. The sewing machine 100 includes a sewing machine frame 110, a needle up / down movement mechanism, a lower feed mechanism 20 as a lower differential feed mechanism, an upper feed mechanism 30 as an upper differential feed mechanism, a presser mechanism 14, an upper lateral feed mechanism 40, a lower lateral feed mechanism 50, a shuttle mechanism 13, an end detection device 60, and a control device 90.

[0013] The needle up-down movement mechanism imparts up-down movement to the sewing needle 11 . The bottom feed mechanism 20 applies a feed operation from below to the lower workpiece at the needle drop position. The upper feed mechanism 30 applies a feed operation from above to the upper sewing material at the needle drop position. The upper lateral feed mechanism 40 is located behind the upper feed mechanism 30 and applies a moving motion to the upper cloth C1 from above in the left-right direction. The lower transverse feed mechanism 50 is located behind the lower feed mechanism 20 and applies a moving motion to the lower cloth C2 from below in the left-right direction.

[0014] The edge detecting device 60 detects the side edges of the upper cloth C1 and the lower cloth C2 behind the lower feed mechanism 20 and the upper feed mechanism 30 and in front of the lower and upper lateral feed mechanisms 40, 50. In this embodiment, a configuration for detecting the right edges of the upper cloth C1 and the lower cloth C2 is exemplified, but a configuration for detecting the left edges may also be used. The presser foot mechanism 14 applies a presser foot pressure to the sewing material on the needle plate 101 . The shuttle mechanism captures the loop of needle thread from the needle 11 and entangles the bobbin thread to form a stitch. The control device 90 controls the operation of each of the above components. The sewing machine 100 is equipped with various components such as a thread take-up mechanism and thread tensioner that are included in a typical lock stitch sewing machine, but these are well known and therefore will not be described here.

[0015] [Sewing machine frame] The sewing machine frame 110 supports or houses each of the components of the sewing machine 100 described above. The sewing machine frame 110 has a sewing machine bed portion 111 , a vertical body portion 112 , and a sewing machine arm portion 113 . The sewing machine bed portion 111 is located at the bottom of the sewing machine 100 and extends in the left-right direction. The upright body portion 112 stands upright from the right end portion of the sewing machine bed portion 111. The machine arm 113 extends leftward from the upper end of the upright body 112 .

[0016] [Needle vertical movement mechanism] The needle up-down movement mechanism is disposed inside the sewing machine arm portion 113, is driven to rotate by the sewing machine motor 15 (see FIG. 7), and has an upper shaft along the left-right direction. Furthermore, the needle up-down movement mechanism includes a needle bar 12 that holds the sewing needle 11 at its lower end, and a crank mechanism that converts the rotational force of the upper shaft into a reciprocating driving force for up-down movement and transmits it to the needle bar. The upper shaft and crank mechanism are well known and are therefore not shown.

[0017] [Shuttle mechanism] The shuttle mechanism 13 is a vertical full-rotating shuttle mechanism that is driven by power from the sewing machine motor 15 and is located below the needle plate 101. Note that a horizontal shuttle or a half-rotating shuttle may also be used.

[0018] [Press mechanism] The presser foot 14 has a presser foot 141 that presses down the lower cloth C2 and the upper cloth C1 on the needle plate 101, a presser bar 142 that supports the lower end of the presser foot 141, a presser spring (not shown) that applies a downward pressing force to the presser foot 141 via the presser bar 142, and a presser motor 143 (see FIG. 7) that adjusts the pressing pressure of the presser foot 141.

[0019] The presser bar 142 is supported inside the sewing machine arm portion 113 so as to be movable up and down. The upper end of the pressure bar 142 is pressed downward by a pressure spring, and the pressure motor 143 can change the amount of contraction of the pressure spring via a cam mechanism, thereby allowing the pressure motor 143 to arbitrarily adjust the pressure of the presser foot 141. The presser foot 141 has the function of supporting the left and right upper belts 31, 32 (described later) through which the upper feed mechanism 30 feeds the upper cloth C1, and by adjusting the pressing pressure, the contact pressure of the left and right upper belts 31, 32 against the upper cloth C1 can be adjusted. Furthermore, the presser motor 143 can raise the presser bar 142 via a cam mechanism, thereby releasing the presser foot 141 from pressing the lower cloth C2 and the upper cloth C1.

[0020] [Bottom feed mechanism] The lower feed mechanism 20 includes a lower left belt 21 and a lower right belt 22 as conveyor belts, a lower left motor 23, a lower right motor 24, a guide frame 25, and a tension roller 26.

[0021] The lower left motor 23 and the lower right motor 24 are both motors whose movement amount can be arbitrarily controlled, such as a DC motor, an AC motor, or a stepping motor. The lower left motor 23 and the lower right motor 24 each apply a conveying force to the lower left belt 21 and the lower right belt 22 via a pulley provided on the output shaft.

[0022] The lower left belt 21 is an endless loop and is stretched between a pulley of the lower left motor 23 and a guide frame 25 . The lower right belt 22 is an endless loop and is stretched between a pulley of the lower right motor 24 and a guide frame 25 .

[0023] Guide frame 25 is disposed at the needle drop position below needle plate 101, and has guide grooves formed on both the left and right sides of the needle hole along the front-to-rear direction. A lower left belt 21 is hung over the guide groove on the left side of the needle hole, and a lower right belt 22 is hung over the guide groove on the right side of the needle hole. A conveying force is applied to lower-left belt 21 and lower-right belt 22 from lower-left motor 23 and lower-right motor 24 so that they are conveyed forward when passing through their respective guide grooves. An opening is formed in needle plate 101 so that the upper surfaces of lower-left belt 21 and lower-right belt 22 that pass through the respective guide grooves of guide frame 25 are exposed upward.

[0024] Each guide groove of the guide frame 25 is formed slightly shallower than the thickness of the lower left belt 21 and the lower right belt 22, and the upper surfaces of the lower left belt 21 and the lower right belt 22 when passing through each guide groove are slightly higher than the upper surface of the needle plate 101 and come into contact with the lower surface of the lower cloth C2.

[0025] By controlling the lower left motor 23 and the lower right motor 24 to drive the lower left motor 23 and the lower right motor 24 at the same speed, the lower cloth C2 can be conveyed straight in the front-to-rear direction at the needle drop position. Furthermore, by controlling the lower left motor 23 and the lower right motor 24, if the lower left motor 23 is driven at a higher speed than the lower right motor 24, the left side of the lower cloth C2 can be fed faster at the needle drop position and the cloth can be transported so as to turn to the right. Furthermore, by controlling the lower left motor 23 and the lower right motor 24, if the lower right motor 24 is driven at a higher speed than the lower left motor 23, the right side of the lower cloth C2 can be fed faster at the needle drop position, and the cloth can be transported so as to turn to the left. In addition, the curvature can be changed depending on the magnitude of the speed difference (conveyance amount difference) between the left and right sides.

[0026] [Upper feed mechanism] The upper feed mechanism 30 includes an upper left belt 31 and an upper right belt 32 as endless circular conveying belts, an upper left motor 33 that serves as the driving source for feeding the upper left belt 31, an upper right motor 34 that serves as the driving source for feeding the upper right belt 32, a first belt guide 35 provided on the presser foot 141, a second belt guide 36 that guides each of the upper belts 31, 32 from the upper left motor 33 and the upper right motor 34 to the first belt guide 35, and tension rollers 37 for the upper left belt 31 and the upper right belt 32.

[0027] The upper left motor 33 and the upper right motor 34 each have a pulley on the output shaft, and drive the upper left belt 31 and the upper right belt 32. The upper left motor 33 and the upper right motor 34 are both motors whose movement amount can be controlled as desired, such as a DC motor, an AC motor, or a stepping motor.

[0028] The second belt guide 36 guides the transport of the upper left belt 31 and the upper right belt 32 between the pulleys of the upper left motor 33 and the upper right motor 34 and the first belt guide 35 supported by the presser foot 141 . The second belt guide 36 includes an upper guide arm 361 and a lower guide arm 362 . The upper guide arm 361 has an upper end rotatably connected to the lower part of a motor bracket 38 that supports the upper left motor 33 and the upper right motor 34 . The upper end of the lower guide arm 362 is connected to the lower end of the upper guide arm 361 , and the lower end is rotatably connected to the upper end of the presser foot 141 . From the upper end of the upper guide arm 361 to the lower end of the lower guide arm 362, guide rollers for guiding the upper left belt 31 and the upper right belt 32 are arranged at various locations. This allows the second belt guide 36 to guide the left upper belt 31 and the right upper belt 32 along the upper guide arm 361 and the lower guide arm 362 that are connected in a bent state.

[0029] The presser foot 141 retracts upward to release the lower cloth C2 and the upper cloth C1 from the pressed state, and at that time, the bending angles of the upper guide arm 361 and the lower guide arm 362 change. Even in this case, the second belt guide 36 can guide the upper-left belt 31 and the upper-right belt 32 along the upper guide arm 361 and the lower guide arm 362 without slackening.

[0030] The first belt guides 35 are provided on both the left and right sides of the presser foot 141 . The first belt guide 35 holds a roller (not shown) near the rear end of the presser foot 141, and guides the upper left belt 31 and the upper right belt 32 so that the conveying direction changes from rear to front when the upper left belt 31 and the upper right belt 32 move around the roller from above to below. Then, the upper left belt 31 and the upper right belt 32, which have passed through the rollers on both the left and right sides of the needle drop position, convey the upper cloth C1 forward while contacting the upper surface of the upper cloth C1 on the needle plate 101. In addition, the first belt guide 35 is rotatably supported by a support shaft that runs along the left-right direction relative to the presser foot 141, and a tension spring biases the rear end of the first belt guide 35 in a direction that rotates downward. As a result, the upper left belt 31 and the upper right belt 32 that have passed through the rollers convey the upper cloth C1 while being pressed against the upper surface of the upper cloth C1.

[0031] By controlling the upper left motor 33 and the upper right motor 34 to drive them at the same speed, the upper cloth C1 can be transported straight in the front-to-rear direction at the needle drop position. Furthermore, by controlling the upper left motor 33 and the upper right motor 34, if the upper left motor 33 is driven at a higher speed than the upper right motor 34, the left side of the upper cloth C1 can be fed faster at the needle drop position and can be transported so as to turn to the right. Furthermore, by controlling the upper left motor 33 and the upper right motor 34, if the upper right motor 34 is driven at a higher speed than the upper left motor 33, the right side of the upper cloth C1 can be fed faster at the needle drop position, and the cloth can be transported so as to turn to the left. In addition, the curvature can be changed depending on the magnitude of the speed difference (conveyance amount difference) between the left and right sides.

[0032] [Edge detection device] Fig. 3 is a left side view showing a schematic configuration around the needle drop position, Fig. 4 is a perspective view showing the same configuration, and Fig. 5 is a plan view of the end detection device 60. Note that in these figures, the first belt guide 35 of the upper feed mechanism 30 is not shown.

[0033] As described above, at the needle drop position, the lower left belt 21 and lower right belt 22 of the lower feed mechanism 20 and the upper left belt 31 and upper right belt 32 of the upper feed mechanism 30 feed the lower cloth C2 and the upper cloth C1 in the sewing direction (front-to-back direction). An end detection device 60 is arranged upstream of the needle drop position in the sewing direction F, and further, a lower lateral feed mechanism 50 and an upper lateral feed mechanism 40 are arranged upstream of the end detection device 60 in the sewing direction F.

[0034] The edge detection device 60 has upper edge sensors 61 and 62 as upper detection sections, lower edge sensors 63 and 64 as lower detection sections, a sensor holding frame 65, and a partition plate 66 that separates the upper cloth C1 and the lower cloth C2.

[0035] The sensor holding frame 65 has an upper wall portion 651 and a lower wall portion 652 that face each other vertically, and a partition plate 66 is disposed horizontally between the upper wall portion 651 and the lower wall portion 652. The right side end portion of the upper cloth C1 being transported forward passes between the upper wall portion 651 and the partition plate 66, and the right side end portion of the lower cloth C2 being transported forward passes between the lower wall portion 652 and the partition plate 66.

[0036] The lower part of the sensor holding frame 65 is disposed in the sewing machine bed portion 111 so as to be below the upper surface of the needle plate 101. The partition plate 66 is disposed slightly above the upper surface of the needle plate 101 so that the lower cloth C2 can pass between the lower surface of the partition plate 66 and the upper surface of the needle plate 101.

[0037] As shown in Figure 5, upper end sensors 61, 62 are provided on the underside of the upper wall 651, facing downward on both the left and right sides of a reference line L that is parallel to the front-to-rear direction and spaced a predetermined distance S to the right of the needle drop position P. The distance S coincides with the target seam allowance of the upper cloth C1 and the lower cloth C2. The seam allowance is the distance from the edge of the material to the stitch when sewing along that edge. The upper end sensors 61 and 62 are so-called reflective photointerrupters, with both the light source and the light receiving element facing downward. The upper and lower surfaces of the partition plate 66 are reflective surfaces, and the upper end sensors 61 and 62 can receive reflected light from the light source with their light receiving elements.

[0038] The detection outputs of the upper end sensors 61, 62 are input to the control device 90, and the control device 90 can recognize that the right end of the upper cloth C1 is at the detection position from the decrease in the amount of received reflected light. The upper end sensors 61, 62 are provided slightly spaced apart on the left and right sides of the reference line L. That is, the left upper end sensor 61 is disposed at the leftmost position that is permissible when the side end C11 of the upper cloth C1 is positioned at a distance S to the right of the needle drop position P, and the right upper end sensor 62 is disposed at the rightmost position that is permissible when the side end C11 of the upper cloth C1 is positioned at the same position.

[0039] During sewing, when the right side edge C11 of the upper cloth C1 enters between the upper wall portion 651 and the partition plate 66 from the left side and the right side edge of the upper cloth C1 is no longer detected by the left upper edge sensor 61, the control device 90 controls the lateral feed mechanism 40 to move the upper cloth C1 to the right, and when the right side edge C11 of the upper cloth C1 is detected by the right upper edge sensor 62, the control device 90 controls the lateral feed mechanism 40 to move the upper cloth C1 to the left. In this way, the right side edge C11 of the upper cloth C1 is controlled to be maintained between the left and right upper edge sensors 61, 62.

[0040] 5, lower end sensors 63, 64 are provided on the upper surface of the lower wall portion 652. The lower end sensors 63, 64 also consist of reflective photointerrupters. The lower end sensors 63, 64 have the same left-right arrangement as the upper end sensors 61, 62, except that the light source and light receiving element face upward. During sewing, when the right side end C21 of the lower cloth C2 is no longer detected by the left lower end sensor 63 in a state where the right side end C21 of the lower cloth C2 has entered between the lower wall portion 652 and the partition plate 66 from the left side, the control device 90 controls the transverse feed mechanism 50 to move the lower cloth C2 to the right, and when the right side end C21 of the lower cloth C2 is detected by the right lower end sensor 64, the control device 90 controls the transverse feed mechanism 50 to move the lower cloth C2 to the left. In this way, the right side end C21 of the lower cloth C2 is controlled to be maintained between the left and right lower end sensors 63, 64.

[0041] It should be noted that any detection means capable of detecting the cloth edge may be used for the upper end sensors 61, 62 and the lower end sensors 63, 64, without being limited to photointerrupters. For example, a microswitch or the like may be used to detect that the seam allowance is about to exceed the distance S when the right end of the upper cloth C1 or the lower cloth C2 comes into contact with the sensor from the left. Alternatively, the position of the right edge of the upper cloth C1 may be detected by a line sensor extending in the left-right direction instead of the upper edge sensors 61 and 62. Similarly, the position of the right edge of the lower cloth C2 may be detected by a line sensor extending in the left-right direction instead of the lower edge sensors 63 and 64.

[0042] The sensor holding frame 65 is also provided with a position adjustment mechanism, which allows the position to be adjusted in the left-right direction, thereby allowing the distance S, which is the target value for the seam allowance of the upper cloth C1 and the lower cloth C2, to be adjusted as desired.

[0043] [Traverse mechanism] FIG. 6 is a horizontal cross-sectional view illustrating the lower traverse mechanism 50 and the upper traverse mechanism 40. As shown in FIG.

[0044] The lateral feed mechanisms 40, 50 include rollers 41, 51 that feed the upper cloth C1 or the lower cloth C2 in a tangential direction to the outer periphery, a plurality of wheels 42, 52 arranged at uniform intervals along the outer periphery of the rollers 41, 51, a rotating shaft 43, 53 to which the rollers 41, 51 are fixedly mounted, a support frame 44, 54 that rotatably supports the rotating shaft 43, 53, a pair of sprockets 45, 55 and timing belts 46, 56 that transmit torque from a drive source to the rotating shaft 43, 53, and a lateral feed motor 47, 57 as a drive source.

[0045] Each wheel 42, 52 is provided at equal intervals on the outer periphery of the roller 41, 51 and is rotatable around an axis along the tangential direction at each mounting position, allowing the upper cloth C1 or the lower cloth C2, which is fed tangentially in contact with the outer periphery of the roller 41, 51, to move in a direction along the rotation axis 43, 53 relative to the roller 41, 51. In other words, when the upper cloth C1 or the lower cloth C2 is transported along the sewing direction F, the lateral feed mechanisms 40, 50 can impart movement along the left-right direction to the upper cloth C1 or the lower cloth C2 without impeding the transport.

[0046] Between the rollers 41 and 51 of the transverse feed mechanisms 40 and 50, a substantially horizontal partition plate 48 is disposed at the same height as the partition plate 66 of the end detection device 60 described above. The upper cloth C1 is conveyed between the upper surface of the partition plate 48 and the roller 41 of the upper transverse feed mechanism 40, and the lower cloth C2 is conveyed between the lower surface of the partition plate 48 and the roller 51 of the lower transverse feed mechanism 50. The upper cloth C1 and the lower cloth C2 are subjected to back pressure by the partition plate 48, and are able to obtain contact pressure with the rollers 41, 51, thereby providing a good transverse feed operation.

[0047] [Sewing machine control system] FIG. 7 is a block diagram showing the control system of the sewing machine 100. As shown in the figure, sewing machine 100 is equipped with a control device 90 that controls the operation of each component. Motor drive circuits 15a, 143a, 23a, 24a, 33a, 34a, 47a, and 57a of sewing machine motor 15, presser foot motor 143, lower left motor 23, lower right motor 24, upper left motor 33, upper right motor 34, upper cross feed motor 47, and lower cross feed motor 57 are connected to control device 90. Encoders 151, 144, 231, 241, 331, 341, 471, and 571 that detect the rotation speeds of the sewing machine motor 15, presser foot motor 143, lower left motor 23, lower right motor 24, upper left motor 33, upper right motor 34, upper traverse feed motor 47, and lower traverse feed motor 57 are also provided. These encoders 151, 144, 231, 241, 331, 341, 471, and 571 are also connected to motor drive circuits 15a, 143a, 23a, 24a, 33a, 34a, 47a, and 57a.

[0048] The control device 90 includes a CPU 91, a ROM 92, a RAM 93, and an EEPROM 94 (registered trademark), and executes various operational controls described below. The ROM 92 stores the basic system program. Various setting data and other programs are also stored in the EEPROM 94. Note that the above-mentioned various setting data and programs may be stored in a nonvolatile storage device such as a flash memory, an EPROM, or an HDD instead of the EEPROM. The CPU 91 executes various programs stored in the ROM 92 and EEPROM 94. The RAM 93 is a memory that serves as a work area for the CPU 91.

[0049] Furthermore, upper end sensors 61 and 62 and lower end sensors 63 and 64 are connected to the control device 90 via interfaces 61a, 62a, 63a, and 64a.

[0050] Furthermore, an operation input unit 96 is connected to the control device 90 via an interface 96a. The operation input unit 96 has an input screen 961, which displays information required when inputting various settings. The operation input unit 96 also allows the user to input settings such as the stitch pitch, the left and right feed amounts of the lower feed mechanism 20 and the upper feed mechanism 30, and the set value of the pressure applied by the presser foot mechanism 14 during sewing.

[0051] For example, the input screen 961 allows the user to set and input the feed amount per stitch (sewing pitch) of the lower left belt 21 and lower right belt 22 of the lower feed mechanism 20 and the feed amount per stitch of the upper left belt 31 and upper right belt 32 of the upper feed mechanism 30 using the setting screen G1 shown in Figure 8. Display frame D1 on setting screen G1 displays the set value of the feed amount per stitch for the lower left belt 21, display frame D2 displays the set value of the feed amount per stitch for the lower right belt 22, display frame U1 displays the set value of the feed amount per stitch for the upper left belt 31, and display frame U2 displays the set value of the feed amount per stitch for the upper right belt 32. The set values ​​of the display frames D1, D2, U1, and U2 can be increased or decreased individually using the increase / decrease keys K1 and K2.

[0052] The sewing machine 100 can sew according to the settings on the setting screen G1. In this case, by individually setting the feed amount per stitch for each of the lower left belt 21, the lower right belt 22, the upper left belt 31, and the upper right belt 32 and creating a difference between the left and right, differential feed can be performed for the upper cloth C1 and the lower cloth C2, with a difference between the left and right.

[0053] Furthermore, regardless of the above artificial settings, the sewing machine 100 can also perform automatic feed control, in which the lower feed mechanism 20, the upper feed mechanism 30, and the upper and lower side feed mechanisms 40, 50 are controlled based on the detection of the end detection device 60 in accordance with the control program 941 executed by the CPU 91 to perform differential feed. This automatic feed control will now be described.

[0054] [Automatic feed control] 9 to 11 are plan views of the needle plate 101 showing the sequential changes in the feed state of the workpiece under automatic feed control. For convenience, each of Figs. 9 to 11 shows only the configuration of the upper feed mechanism 30 and the upper lateral feed mechanism 40 that feed the upper cloth C1, but automatic feed control is also performed on the lower feed mechanism 20 and the lower lateral feed mechanism 50 in the same way.

[0055] 9, the CPU 91 controls the lower feed mechanism 20 and the upper feed mechanism 30 to feed linearly forward without performing differential feed between the left and right sides. On the other hand, the CPU 91 controls the upper and lower lateral feed mechanisms 40, 50 based on the detection of the edge detection device 60 so that the needles of the upper cloth C1 and the lower cloth C2 drop at a certain distance S from the side edges C11, C21. Specifically, when the right end of the upper cloth C1 is no longer detected by the upper end sensor 61 on the left side of the end detection device 60, the CPU 91 controls the lateral feed mechanism 40 to move the upper cloth C1 to the right, and when the right end of the upper cloth C1 is detected by the upper end sensor 62 on the right side, the CPU 91 controls the upper lateral feed mechanism 40 to move the upper cloth C1 to the left. At the same time, when the right end of the lower cloth C2 is no longer detected by the lower end sensor 63 on the left side of the end detection device 60, the CPU 91 controls the lateral feed mechanism 50 to move the lower cloth C2 to the right, and when the right end of the lower cloth C2 is detected by the lower end sensor 64 on the right side, the CPU 91 controls the lower lateral feed mechanism 50 to move the lower cloth C2 to the left.

[0056] On the other hand, as shown in Figure 10, when the trailing ends of the upper cloth C1 and the lower cloth C2 approach the needle drop position P, the rollers 41 and 51 of the upper and lower lateral feed mechanisms 40 and 50 deviate from the upper cloth C1 and the lower cloth C2, respectively, and a state occurs in which feeding to the left and right becomes impossible. Hereinafter, this state will be referred to as the "deviation state." This "deviation state" occurs when the end portions of the upper cloth C1 and the lower cloth C2 in the front-to-back direction have already passed through the rollers 41 and 51, and may also occur before the end portions pass through the rollers 41 and 51 if the right side end portions C11 and C21 of the upper cloth C1 and the lower cloth C2 are curved to the left.

[0057] Furthermore, after passing through the "deviating state," the state shifts to the "final state" where sewing is performed near the end portions of the upper cloth C1 and the lower cloth C2. In this "final state," as shown in Fig. 11, the left-right guidance of the upper cloth C1 and the lower cloth C2 is switched from the lateral feed mechanisms 40, 50 to the upper feed mechanism 30 and the lower feed mechanism 20, and the side end portions C11, C21 of the upper cloth C1 and the lower cloth C2 pass through the detection range of the end detector 60.

[0058] Figure 12 is a diagram showing the relationship between the accumulated value of the operation amount of the traverse feed motor 47 of the traverse feed mechanism 40 and the elapsed time during the state transitions between the "normal feed state," "deviation state," and "final state." In Figure 12, the vertical axis represents the accumulated value of the lateral guided operation amount of the traverse feed motor 47, with the lower part of the vertical axis representing guidance to the left. The values ​​on the horizontal axis represent thousandths of a second (ms). FIG. 13 is a plan view showing a sewing section W1 in the "normal feed state," a sewing section W2 in the "deviation state," and a sewing section W3 in the "final state" of a stitch formed on the side edge C11 of the upper cloth C1.

[0059] The automatic feed control executed by the CPU 91 will be described with reference to Figures 12 to 14. Figure 14 is a flowchart of the automatic feed control. Here, we will explain the automatic feed control performed by the CPU 91 using the lateral feed mechanism 40 and the upper feed mechanism 30 based on detection by the end detection device 60 for the upper cloth C1, but when the lower cloth C2 is the target, the same automatic feed control is performed by the lateral feed mechanism 50 and the lower feed mechanism 20 based on detection by the end detection device 60.

[0060] In the automatic feed control, when sewing is started by driving the sewing machine motor 15, the CPU 91 causes the edge detector 60 to detect the side edge C11 of the upper cloth C1 at short intervals (for example, every few ms) (step S1). At the beginning of sewing, sewing is performed in the sewing section W1 in the "normal feed state." That is, for the upper feed mechanism 30, the upper left motor 33 and the upper right motor 34 are controlled so that there is no difference in the feed amount between the left and right, and linear feed is performed at the needle drop position P.

[0061] Then, based on the short-cycle detection by the end detector 60, the CPU 91 controls the traverse motor 47 of the traverse mechanism 40 to rotate forward or backward at a specified operating amount (step S3: see FIG. 9). For example, as shown in FIG. 13, in the first half of the sewing section W1 in the "normal feed state," the shape of the side end C11 of the upper cloth C1 is linear, so the lateral feed mechanism 40 is controlled to guide the upper cloth C1 alternately to the left and right in small increments, and the upper cloth C1 is fed in an almost linear manner. In addition, in the latter half of the sewing section W1, since the shape of the side end C11 of the upper cloth C1 is inclined to the left, the lateral feed mechanism 40 is controlled to guide the upper cloth C1 left and right while increasing the frequency of guiding it to the right, and the upper cloth C1 is fed in accordance with the inclination of the side end C11.

[0062] Furthermore, the CPU 91 adds up the amount of movement of the traverse motor 47 for each operation and records it in the RAM 93 (step S5). Then, every time the integrated value of the operation amount of the traverse motor 47 is calculated, it is determined whether or not the "deviation state" in FIG. 10 described above has occurred (step S7).

[0063] The "deviation state" occurs when the trailing end of the upper cloth C1 approaches the roller 41 of the transverse feed mechanism 40. In the sewing section W2 in the "deviation state", the roller 41 of the lateral feed mechanism 40 deviates from the upper cloth C1, so even if the edge detecting device 60 detects the upper cloth C1 and the lateral feed motor 47 is driven in a direction based on the detection, the position of the side edge C11 of the upper cloth C1 does not change. Therefore, the lateral feed motor 47 is repeatedly driven in the same direction with the same movement amount in short cycles.

[0064] For example, as shown in Figure 13, if the end of the upper cloth C1 is curved or inclined to the left, when a deviation occurs, the upper end sensor 61 on the left side of the end detection device 60 is likely to be in a state where it does not detect the upper cloth C1, so the CPU 91 will repeatedly perform a rightward guidance operation using the lateral feed motor 47. In this case, as shown in FIG. 12, in the sewing section W2 in the "deviation state", the integrated value of the operation amount of the lateral feed motor 47 becomes linear in a predetermined inclined direction (downward to the right in this embodiment).

[0065] The CPU 91 calculates the slope of the change in the integrated value of the amount of movement of the traverse motor 47 each time it calculates the integrated value, and can detect the occurrence of a "deviation state" depending on whether the same slope continues a predetermined number of times.

[0066] If the occurrence of the "deviation state" is not detected in step S7, the CPU 91 returns the process to step S1 and continues sewing in the "normal feed state." On the other hand, when the occurrence of a "deviation state" is detected, as shown in FIG. 12, the CPU 91 calculates the slope of the integrated value of the operating amount of the lateral feed motor 47 during a predetermined period (referred to as the "sample period T") prior to the start of the sewing section W2 of the "deviation state" (step S9). The length of the sample period T may be set arbitrarily. The overall slope of the integrated value of the operation amount of the traverse feed motor 47 during the sample period T may be calculated from the average of the individual slopes within the sample period T.

[0067] The slope of the integrated value of the amount of movement of the lateral feed motor 47 correlates with the slope of the side edge C11 of the upper cloth C1. As shown in FIG. 13, the inclination of the side edge C11 of the upper cloth C1 during the sample period T is close to the inclination of the sewing section W3 in the "final state" which is the end of the upper cloth C1.

[0068] Therefore, when the CPU 91 acquires the slope of the integrated value of the operating amount of the lateral feed motor 47 during the sample period T, it determines, based on this, the left and right differential feed amounts of the upper feed mechanism 30 for guiding the upper cloth C1 in the left and right directions in the sewing section W3 in the "final state" (step S11). For example, as shown in Figure 13, when the side end portion C11 of the end portion of the upper cloth C1 is inclined to the left, the difference value between the left and right feed amounts is determined so that the operating amount of the upper right motor 34 is greater than the operating amount of the upper left motor 33.

[0069] The difference between the left and right feed amounts may be determined by preparing table data in advance in the EEPROM 94, which stores the difference between the left and right feed amounts relative to the slope of the integrated value of the operating amount of the lateral feed motor 47 during the sample period T, and the CPU 91 may refer to this table data when necessary. Alternatively, the CPU 91 may perform calculations based on a function that defines the correspondence between the value of the gradient of the integrated value of the movement amount of the lateral feed motor 47 during the sample period T and the value of the left and right differential feed amount.

[0070] Then, the CPU 91 performs sewing of the sewing section W3 in the "final state" while controlling the operating amount of the upper left motor 33 and the upper right motor 34 of the upper feed mechanism 30 based on the determined difference between the left and right feed amounts and the set sewing pitch (step S13).

[0071] Since the length of the sewing section W3 in the "final state" is short, the difference between the left and right feed amounts is maintained and sewing is performed with the specified number of stitches, and then the driving of the sewing machine motor 15 and the upper left motor 33 and upper right motor 34 of the upper feed mechanism 30 is stopped, and sewing based on the automatic feed control is completed. The predetermined number of stitches for the sewing section W3 in the "final state" may be determined in accordance with the set stitch pitch.

[0072] [Technical Effects of the Embodiments of the Invention] In the above-mentioned sewing machine 100, the CPU 91 of the control device 90 controls the operation of the lateral feed mechanisms 40, 50 to guide the upper cloth C1 and the lower cloth C2 in the left-right direction during the sewing section W1 in the "normal feed state" so as to maintain a constant seam allowance, and in the sewing section W3 in the "final state" where the rollers 41, 51 of the lateral feed mechanisms 40, 50 deviate from the upper cloth C1 or the lower cloth C2 for each of the upper cloth C1 and the lower cloth C2, the upper feed mechanism 30 or the lower feed mechanism 20 controls the operation of the lateral feed mechanism 30 or the lower feed mechanism 20 to guide the upper cloth C1 or the lower cloth C2 in the left-right direction by differential feed so as to maintain a constant seam allowance. Therefore, even if the lateral feed mechanisms 40, 50 are positioned upstream of the needle drop position P in the sewing direction F and the lateral feed mechanisms 40, 50 cannot perform a guiding operation near the end portions of the upper cloth C1 and the lower cloth C2, the upper cloth C1 and the lower cloth C2 can be transported in the correct direction or in the correct orientation, and the side end portion C11 of the upper cloth C1 and the side end portion C21 of the lower cloth C2 can be sewn together properly with reduced misalignment up to the end portions.

[0073] In addition, the sewing machine 100 determines that the rollers 41, 51 of the lateral feed mechanisms 40, 50 have deviated from the upper cloth C1 or the lower cloth C2 when the detection state or non-detection state of the side end portions C11, C21 of the upper cloth C1 or the lower cloth C2 by the end detection device 60 does not change in response to the guiding operation of the lateral feed mechanisms 40, 50 for the upper cloth C1 or the lower cloth C2, respectively. That is, as explained in step S7 of FIG. 14, the CPU 91 judges that a "deviation state" has occurred when the position of the side end C11 of the upper cloth C1 does not change or when the side end C11 of the upper cloth C1 continues to be undetected even when the lateral feed motor 47 is repeatedly driven in the same direction with the same amount of movement (the same applies to the lower cloth C2 and the roller 51). This allows for proper switching from guiding the upper cloth C1 or the lower cloth C2 by the lateral feed mechanisms 40, 50 to guiding the upper cloth C1 or the lower cloth C2 by the upper feed mechanism 30 or the lower feed mechanism 20.

[0074] Furthermore, when the CPU 91 of the control device 90 judges that each of the upper cloth C1 and the lower cloth C2 is in a "deviation state," the sewing machine 100 determines a differential feed amount, which is the difference between the feed amounts to the left and right of the needle drop position P by the upper feed mechanism 30 or the lower feed mechanism 20, depending on the amount of induced operation by the lateral feed motors 47, 57 of the lateral feed mechanisms 40, 50, i.e., the slope of the integrated value of the operation amount, during the sample period T immediately before the detection state or non-detection state of the side end portions C11, C21 of the upper cloth C1 or the lower cloth C2 by the end detection device 60 stops changing. As a result, even if the end detection device 60 is positioned upstream of the needle drop position P in the sewing direction F and the side end portions C11, C21 cannot be detected until the end portion of the upper cloth C1 or the lower cloth C2 is sewn, the upper cloth C1 and the lower cloth C2 can be transported in the correct direction or orientation, and the side end portion C11 of the upper cloth C1 and the side end portion C21 of the lower cloth C2 can be sewn together properly up to the end portion.

[0075] [others] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. For example, in the embodiments, a component integrally formed from a single member may be replaced with a component divided into multiple members that are connected or fixed to each other. Furthermore, a component formed by connecting multiple members may be replaced with a component integrally formed from a single member. In addition, the details shown in the embodiments may be modified as appropriate without departing from the spirit of the invention.

[0076] For example, the lower feed mechanism 20 or the upper feed mechanism 30 is not limited to a belt feed mechanism, but may be a mechanism that feeds the upper cloth C1 or the lower cloth C2 by any method that can provide a difference in feed amount between the left and right sides at the needle drop position P. For example, a mechanism that feeds by a feed dog or a roller may also be used.

[0077] Furthermore, the method for detecting deviation of the rollers 41, 51 of the lateral feed mechanisms 40, 50 from the upper cloth C1 or the lower cloth C2 is not limited to the above-described method. For example, a dedicated detection means such as a sensor may be provided. [Explanation of symbols]

[0078] 20 Lower feed mechanism (differential feed mechanism) 23 Lower left motor 24 Lower right motor 30 Upper feed mechanism (differential feed mechanism) 33 Upper left motor 34 Upper right motor 40,50 Traverse mechanism 41,51 Laura 47,57 Traverse motor 60 Edge detection device 61,62 Upper end sensor 63,64 Lower edge sensor 90 Control device 91 CPU 100 sewing machines 101 Needle plate 941 Control Program C1 Upper fabric (upper sewing material) C2 Lower fabric (lower sewing material) C11,C21 side end F Sewing direction L Reference Line P Needle entry position S distance T sample period W1 Sewing section (normal feed state) W2 Sewing section (deviation state) W3 Sewing section (final state)

Claims

1. an edge detection device that detects the position of each side edge in the left and right direction upstream of the needle drop position in the sewing direction for each of the upper and lower sewing objects to be sewn together; a lower and upper lateral feed mechanism for moving each of the lower and upper sewn objects in the left and right direction by rollers, the lower and upper lateral feed mechanisms being located upstream of the end detection device in the sewing direction; lower and upper differential feed mechanisms that can feed the lower and upper sewing objects by different amounts of feed in the sewing direction on the left and right sides of the needle drop position; Equipped with For each of the lower and upper sewing materials, While the roller of the lateral feed mechanism is in contact with the sewing material, the lateral feed mechanism guides the sewing material in the left-right direction so as to maintain a constant seam allowance, When the roller of the lateral feed mechanism comes off the sewing material, the differential feed mechanism guides the sewing material in the left and right directions by the differential feed so as to maintain a constant seam allowance. A sewing machine comprising: a control device that controls the lower and upper lateral feed mechanisms and the lower and upper differential feed mechanisms.

2. The differential feed mechanism includes: While the roller of the lateral feed mechanism is in contact with the sewing material, 2. The sewing machine according to claim 1, wherein the sewing machine feeds the lower and upper workpieces in a manner that there is no difference in the feed amount in the sewing direction between the left and right sides of the needle drop position.

3. The differential feed mechanism includes:

3. The sewing machine according to claim 1, wherein the workpiece is conveyed by a belt feed.

4. The control device For each of the lower and upper sewing materials, When the detection state or non-detection state of the side edge of the sewing workpiece by the edge detection device does not change in response to the guiding operation of the roller of the lateral feed mechanism with respect to the sewing workpiece, 3. The sewing machine according to claim 1, wherein it is determined that the roller of the lateral feed mechanism has come off the workpiece.

5. The control device For each of the lower and upper sewing materials, When it is determined that the roller of the lateral feed mechanism has come off the sewing workpiece, depending on the amount of induction operation by the lateral feed mechanism immediately before the state of detection or non-detection of the side edge of the sewing workpiece by the edge detection device no longer changes, determining a difference in the amount of feed in the sewing direction between the left and right sides of the needle drop position by the differential feed mechanism; 5. The sewing machine according to claim 4.

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