Sewing machine

Abstract

To properly feed a sewn article when height of the sewn article differs between feeding positions of right and left conveyor belts on both sides of a needle location.SOLUTION: A sewing machine comprises: a needle vertical movement mechanism to vertically move a sewing needle 11 by a sewing machine motor 16; an upper feeding mechanism 40 to feed a sewn article on a needle plate 101 by making conveyor belts 41, 42 individually abut against the sewn article from above on right and left sides of a needle location; detection parts 48, 49, 762 to detect height of the sewn article at a feeding position of the conveyor belt 41 on the left side and height of the sewn article at a feeding position of the conveyor belt 42 on the right side, or detect the difference between these heights; and a control device 90 to control operation of the needle vertical movement mechanism and the upper feeding mechanism 40. The control device 90 controls so as to adjust feeding drive of the right and left conveyor belts 41, 42 of the upper feeding mechanism 40 based on the detection of the detection parts 48, 49, 762.SELECTED DRAWING: Figure 11

Description

[Technical field]

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

[0002] There is a sewing machine in which an upper feed section is provided on each of the left and right sides of the needle drop position above the needle plate, and the sewing workpiece is fed by a conveyor belt provided in each upper feed section. In this sewing machine, a detection arm directly contacts the sewing workpiece on the needle plate from above to detect the thickness of the sewing workpiece (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-158497 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above sewing machine, the thickness of the sewn material was measured at one point on the sewn material, so if there was a difference in the thickness of the sewn material on both sides of the needle drop position where the left and right upper feed parts perform belt feed, it was not possible to detect this.

[0005] An object of the present invention is to perform appropriate feeding when there is a difference in height of the workpiece at the feeding positions of the left and right conveyor belts on both sides of the needle drop position. [Means for solving the problem]

[0006] The present invention relates to a sewing machine, a needle up-down movement mechanism that moves the sewing needle up and down using a sewing machine motor; an upper feed mechanism that feeds the workpiece on the needle plate by individually contacting the conveyor belt from above on both the left and right sides of the needle drop position; a detection unit for detecting a height of the workpiece at a feed position of the left conveyor belt and a height of the workpiece at a feed position of the right conveyor belt, or detecting a difference therebetween; A control device that controls the operation of the needle up and down movement mechanism and the upper feed mechanism, The control device is characterized in that it performs control to adjust the drive of the feed of the left and right conveyor belts of the upper feed mechanism based on the detection of the detection unit. Effect of the Invention

[0007] The sewing machine of the present invention is capable of performing appropriate feeding when there is a difference in height of the workpiece at the feeding positions of the left and right conveyor belts on both sides of the needle drop position. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a rear view of the sewing machine according to the embodiment of the present invention. [Diagram 2] FIG. [Diagram 3] FIG. [Figure 4] FIG. 2 is a perspective view showing the top surface of the left end portion of the bed of the sewing machine with the presser foot not shown. [Diagram 5] FIG. 4 is a perspective view of a guide frame of the lower feed mechanism. [Figure 6] FIG. 2 is a perspective view of a feed mechanism in which four conveyor belts are in a front-rear differential feed state. [Figure 7] 1 is a perspective view of a feed mechanism in which four conveyor belts are in a left-right differential feed state; [Figure 8] 4 is a perspective view of the vicinity of a cloth presser mechanism that presses a sewing material from above on the needle plate. FIG. [Figure 9] FIG. [Figure 10] FIG. [Figure 11] FIG. 2 is a block diagram showing a control system of the sewing machine. [Figure 12] 13 is a rear view of the presser foot mechanism and its surroundings, showing an example in which a distance sensor is used as a detection unit; FIG. [Figure 13] 13 is a perspective view showing the upper left end surface of a sewing machine bed, illustrating an example in which a needle hole is directly formed in a needle plate. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [Summary of the embodiment of the invention] A sewing machine 100 according to an embodiment of the present invention will be described in detail below. FIG. 1 is a rear view of the sewing machine 100, FIG. 2 is a left side view of the sewing machine 100, and FIG. Hereinafter, the downstream side in the feed direction of the sewing workpiece (see FIG. 12) will be referred to as the "front", the upstream side in the feed 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 will be referred to as the "upper", and the vertically downward will be referred to as the "lower". The front-to-rear, left-to-right, and up-to-down directions are perpendicular to each other. In the following description, it is assumed that the sewing machine 100 is placed on a horizontal surface, and the front-to-back and left-to-right directions are horizontal.

[0010] As an example of a sewing machine 100 according to an embodiment of the present invention, a so-called lock stitch sewing machine is shown. The sewing machine 100 includes a sewing machine frame 110, a needle up-down movement mechanism, a lower feed mechanism 20 as a feed device, an upper feed mechanism 40 as a feed device, a cloth presser mechanism 70 as a presser mechanism, a shuttle mechanism, a positioning ruler 50 (see FIG. 11), and a retraction mechanism 60 (see FIG. 11). The needle up-down movement mechanism imparts an up-down movement to the sewing needle 11 . The bottom feed mechanism 20 applies a feed motion to the workpiece on the needle plate 101 from below. The upper feed mechanism 40 applies a feed motion to the workpiece on the needle plate 101 from above. The presser mechanism 70 applies a presser pressure to the workpiece on the needle plate 101 . The shuttle mechanism captures the loop of upper thread from the sewing needle 11 and entangles the bobbin thread to form a stitch. The positioning ruler 50 abuts against the side edge of the workpiece to determine the edge width, which is the distance from the side edge to the seam. The retraction mechanism 60 holds the belt guide 44 of the upper feed mechanism 40 in a retracted position to avoid interference when the positioning ruler 50 is used. The sewing machine 100 is equipped with various components such as a thread take-up mechanism and thread tensioner that are equipped in a typical lock stitch sewing machine, but as these are well known, a description thereof will be omitted.

[0011] [Sewing machine frame] The sewing machine frame 110 supports or houses each component 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 sewing machine arm portion 113 extends leftward from the upper end portion of the upright body portion 112 .

[0012] [Needle vertical movement mechanism] FIG. 4 is a perspective view showing the upper surface of the left end portion of the sewing machine bed portion 111, with the presser foot, which will be described later, omitted. The needle up-down movement mechanism is disposed inside the sewing machine arm portion 113 along the left-right direction, and has an upper shaft that is rotated by the sewing machine motor 16 (see FIG. 11). Furthermore, as shown in Figures 1 to 4, 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 not shown in the figure because they are well known.

[0013] Needle bar 12 extends in the vertical direction and is supported at the lower left end of sewing machine arm portion 113 so as to be movable up and down. Sewing needle 11 is held at the lower end of needle bar 12 and moves up and down together with needle bar 12. A needle plate 101 made of a horizontal flat plate is provided below needle bar 12 on the upper surface of sewing machine bed portion 111.

[0014] A composite opening 102 is formed at the needle drop position of the sewing needle 11 relative to the needle plate 101. In the composite opening 102 of the needle plate 101, a pinhole member 30 having a pinhole 13 and a rear left lower belt 21, a front left lower belt 22, a front right lower belt 23 and a rear right lower belt 24 of a lower feed mechanism 20 described later are arranged so as to be exposed upward. In other words, the composite opening 102 has a shape in which a plurality of rectangular openings through which the pinhole member 30 and the lower belts 21 to 24 are exposed are integrally combined.

[0015] [Kettle mechanism] The shuttle mechanism has an inner shuttle 14 and an outer shuttle 15 provided below the needle hole member 30 of the needle plate 101, and a shuttle shaft (not shown) that rotates the outer shuttle 15, as shown in FIGS. The shuttle shaft is supported rotatably along the left-right direction within the sewing machine bed portion 111. Rotation about an axis along the left-right direction, which is accelerated twice as fast as that of the upper shaft, is input to the shuttle shaft from the above-mentioned upper shaft via a gear mechanism or a belt mechanism.

[0016] The inner hook 14 is housed inside the outer hook 15. Furthermore, the inner hook 14 houses therein a bobbin (not shown) for supplying a lower thread. The outer hook 15 is connected to the left end of the hook shaft and rotates around the inner hook 14. The rotation of the inner hook 14 is restricted so that it does not rotate together with the outer hook 15. The outer hook 15 has a point on its outer periphery for capturing the loop of the upper thread from the sewing needle 11. By rotating, the outer hook 15 can capture the loop of the upper thread with the point and pass the bobbin thread that is being paid out from inside the inner hook 14 through it. The outer shuttle 15 and the inner shuttle 14 are arranged in a stored state inside a substantially cylindrical guide frame 29 of the lower feed mechanism 20, which will be described later.

[0017] [Downfeed mechanism] Fig. 5 is a perspective view of a guide frame 29 of the lower feed mechanism 20, and Figs. 6 and 7 are perspective views of the lower feed mechanism 20. Figs. 6 and 7 show different cases in which lower belts 21 to 24, which will be described later, are hung in different states. The lower feed mechanism 20 will be described in detail below with reference to FIGS.

[0018] The lower feed mechanism 20 includes lower belts 21 to 24 as conveyor belts, a first motor 25, a second motor 26, rotating shafts 27 and 28, a first pulley 31, and a second pulley 32, as shown in the respective drawings. Furthermore, the lower feed mechanism 20 includes a guide frame 29 that guides the lower belts 21 to 24 so that they come into contact with the lower surface of the workpiece, a first pressure mechanism 33, and a second pressure mechanism .

[0019] The first and second motors 25 and 26 are both motors whose operation amount can be arbitrarily controlled, such as a stepping motor or a servo motor. The first and second motors 25 and 26 are arranged in a line up in front and rear, inside the right end portion of the sewing machine bed portion 111, and have their output shafts facing leftward. A first pulley 31 is connected to the output shaft of the first motor 25 on the front side via a rotating shaft 27 . A second pulley 32 is connected to the output shaft of the second motor 26 on the rear side via a rotating shaft 28 .

[0020] The rotary shafts 27 and 28 are both parallel to each other in the left-right direction and are rotatably supported within the sewing machine bed portion 111. The first and second pulleys 31, 32 are supported rotatably around axes extending in the left-right direction within the left end portion of the sewing machine bed portion 111. Rotational motions are imparted to the first and second pulleys 31, 32 by the first motor 25 and the second motor 26 via the rotary shafts 27, 28, respectively. The first and second pulleys 31, 32 are arranged to overlap each other when viewed from the front-rear direction, i.e., they are at the same height and in the same position in the left-right direction.

[0021] The first and second pulleys 31, 32 are each capable of looping over all of the lower belts 21, 22, 23, 24 that are arranged in parallel in the left-right direction. That is, the first pulley 31 has, on its outer circumferential surface, a left groove 311 for passing the rear left lower belt 21 and the front left lower belt 22 therethrough and a right groove 312 for passing the front right lower belt 23 and the rear right lower belt 24 therethrough. The second pulley 32 has, on its outer circumferential surface, a left groove 321 for passing the rear left lower belt 21 and the front left lower belt 22 therethrough, and a right groove 322 for passing the front right lower belt 23 and the rear right lower belt 24 therethrough. The lower belts 21 to 24 have the same width, and the left and right grooves 311, 312, 321, 322 each have a width of at least two belts. As a result, each of the lower belts 21 to 24 can be stretched over the first pulley 31 and the second pulley 32 by appropriately selecting them.

[0022] Each of the lower belts 21 , 22 , 23 , 24 is an endless loop, and is stretched between the guide frame 29 and the first pulley 31 or between the guide frame 29 and the second pulley 32 . The lower belts 21, 22, 23, and 24 are arranged in parallel in order from left to right.

[0023] 2, the guide frame 29 (guide member) is disposed so as to substantially coincide with the pulleys 31, 32 in the left-right direction and to be between the pulleys 31, 32 in the front-rear direction. Furthermore, the guide frame 29 is disposed above the pulleys 31, 32 and immediately below the needle plate 101. As shown in FIG. 5, the guide frame 29 has a bracket portion 295 for fixing it to the inside of the sewing machine bed portion 111, and a cylindrical main body portion 296 for guiding each of the lower belts 21-24.

[0024] The guide frame 29 is disposed directly below the needle plate 101 with the central axis of the main body 296 oriented in the left-right direction. A fitting groove 297 is formed along the front-rear direction in the left-right center of the upper outer circumferential surface of the main body 296. A plate-shaped pinhole member 30 that is long in the front-rear direction is disposed inside the fitting groove 297. The pinhole member 30 has a pinhole 13 that penetrates vertically at the needle drop position. The needle hole member 30 is connected to a needle up-down movement mechanism (not shown) which uses the above-mentioned sewing machine motor 16 as a drive source to move it up and down at the same cycle as the sewing needle 11. This needle up-down movement mechanism moves the needle hole member 30 up and down in the opposite phase to the sewing needle 11. That is, the surface of the needle hole member 30 where the needle hole 13 is formed is at the same height as or slightly higher than the top surface of the needle plate 101 in the phase where the sewing needle 11 is at its bottom dead point, and is at the lowest position where it is lowered furthest from the top surface of the needle plate 101 in the phase where the sewing needle 11 is at its top dead point.

[0025] Further, the main body 296 feeds the workpiece by sliding the lower belts 21-24 in the circumferential direction on the upper part of the outer circumferential surface thereof. For this reason, first to fourth guide portions 291, 292, 293, and 294 for guiding the lower belts 21-24 are provided on the upper part of the outer circumferential surface of the main body 296. The first guide portion 291 is provided to the left rear of the needle hole 13, the second guide portion 292 is provided to the left front of the needle hole 13, the third guide portion 293 is provided to the right front of the needle hole 13, and the fourth guide portion 294 is provided to the right rear of the needle hole 13. Each of the guide portions 291-294 is a protruding strip extending in the front-rear direction, and its width in the left-right direction is equal to or slightly wider than that of each of the lower belts 21-24. The rear end of each of the guide portions 291-294 forms a slope such that the amount of protrusion radially outward from the outer circumferential surface of the main body portion 296 gradually increases toward the front. Also, the front end of each of the guide portions 291-294 forms a slope such that the amount of protrusion radially outward from the outer circumferential surface of the main body portion 296 gradually decreases toward the front.

[0026] The first guide portion 291 is located to the left of the needle hole 13 and rearward of the center of the needle hole 13 over substantially the entire length. The first guide portion 291 has a flat and horizontal guide surface 291a (patterned portion in FIG. 5) forward of the maximum radially outward protrusion of the main body portion 296. The guide surface 291a is disposed so as to face the composite opening 102 of the needle plate 101 when viewed from above. The guide surface 291 a is set so that the outer surface of the rear left lower belt 21 that passes over it in sliding contact therewith is slightly higher than the upper surface of the needle plate 101 . The guide surface 291a is formed so that its front end is located slightly rearward of the center of the needle hole 13 and the rear left lower belt 21 comes into contact with the workpiece rearward of the center of the needle hole 13.

[0027] The second guide portion 292 is located to the left of the needle hole 13 and to the right of the first guide portion 291, and is located forward of the center of the needle hole 13 over substantially the entire length. The second guide portion 292 has a flat and horizontal guide surface 292a (patterned portion in FIG. 5 ) behind the maximum radially outward protrusion of the main body portion 296. The guide surface 292a is disposed so as to face the composite opening 102 of the needle plate 101 when viewed from above. The guide surface 292 a is set so that the outer surface of the front left lower belt 22 that passes over and slides thereon is slightly higher than the upper surface of the needle plate 101 . The guide surface 292a is formed so that its rear end is located slightly forward of the center of the needle hole 13 and the front left lower belt 22 comes into contact with the workpiece forward of the center of the needle hole 13.

[0028] The third guide portion 293 is located to the right of the needle hole 13 and forward of the center of the needle hole 13 over substantially the entire length. The third guide portion 293 has a flat and horizontal guide surface 293a (patterned portion in FIG. 5) behind the maximum radially outward protrusion of the main body portion 296. The guide surface 293a is disposed so as to face the composite opening 102 of the needle plate 101 when viewed from above. The guide surface 293 a is set so that the outer surface of the front right lower belt 23 that passes over and slides thereon is slightly higher than the upper surface of the needle plate 101 . The guide surface 293a is formed such that its rear end is located slightly forward of the center of the needle hole 13 and the front right lower belt 23 comes into contact with the workpiece forward of the center of the needle hole 13.

[0029] The fourth guide portion 294 is located to the right of the needle hole 13 and the third guide portion 293 and rearward of the center of the needle hole 13 over substantially the entire length. The fourth guide portion 294 has a flat and horizontal guide surface 294a (patterned portion in FIG. 5 ) forward of the maximum radially outward protrusion of the main body portion 296. The guide surface 294a is disposed so as to face the composite opening 102 of the needle plate 101 when viewed from above. The guide surface 294 a is set so that the outer surface of the rear right lower belt 24 that passes over it in sliding contact therewith is slightly higher than the upper surface of the needle plate 101 . The guide surface 294a is formed so that its front end is located slightly rearward of the center of the needle hole 13 and the rear right lower belt 24 abuts against the workpiece rearward of the center of the needle hole 13.

[0030] The guide surfaces 291a, 294a are provided behind the center of the needle hole 13, and the guide surfaces 292a, 293a are provided ahead of the center of the needle hole 13. Therefore, when a speed difference (conveyance difference) is provided between the rear left lower belt 21, rear right lower belt 24 on the rear side and the front left lower belt 22, front right lower belt 23 on the front side, the conveying force due to the front and rear feed speed difference (conveyance difference) can be applied to the sewn material without interference between the lower belts 21-24. Therefore, a desired stitch is formed in the differential feed in the front and rear direction, and it is possible to improve the sewing quality.

[0031] The first pressure mechanism 33 applies tension to all of the lower belts 21 to 24 that are stretched between the guide frame 29 and the first pulley 31, thereby preventing slack from occurring. The first pressure mechanism 33, as shown in FIGS. 2, 3 and 6, has a left pressure roller 331, a right pressure roller 332, a support plate 333, and a base block 334.

[0032] The support plate 333 is a long flat plate extending in the front-rear and up-down directions, and is supported by a base block 334 with its longitudinal direction facing diagonally upward and forward. Furthermore, the support plate 333 supports the left pressure roller 331 and the right pressure roller 332 concentrically and rotatably on the left and right surfaces of the upper end portion thereof. The support plate 333 is disposed so that the left pressure roller 331 and the right pressure roller 332 abut against the outer surface of the belt extending between the guide frame 29 and the first pulley 31 from below the rear portion.

[0033] The base block 334 is shared with the second pressure mechanism 34, which will be described later, and supports the components of the first and second pressure mechanisms 33, 34. The base block 334 is fixedly mounted below the guide frame 29 within the sewing machine bed portion 111. The support plate 333 has an elongated hole along its longitudinal direction, and is fastened to the base block 334 by two bolts inserted into the elongated holes. The longitudinal direction of the support plate 333 is oriented in a direction substantially perpendicular to the belt stretched around the first pulley 31. Therefore, by loosening the bolts and moving the support plate 333 along the elongated holes, it is possible to adjust the pressure contact force of the left pressure roller 331 and the right pressure roller 332 against the belt. In other words, it is possible to adjust the tension of the belt passing between the guide frame 29 and the first pulley 31.

[0034] The left pressure roller 331 and the right pressure roller 332 have the same outer diameter, and are supported by a support plate 333 so as to be rotatable about the same axis along the left-right direction. In addition, the left pressure roller 331 and the right pressure roller 332 each have a width in the left-right direction that is twice or more the width of each of the lower belts 21-24. This allows the left pressure roller 331 to come into contact with both the rear left lower belt 21 and the front left lower belt 22 that are stretched between the guide frame 29 and the first pulley 31 . Similarly, the right pressure roller 332 can be brought into contact with either the front right lower belt 23 or the rear right lower belt 24 stretched between the guide frame 29 and the first pulley 31 .

[0035] The second pressure mechanism 34 applies tension to all of the lower belts 21 to 24 that are stretched between the guide frame 29 and the second pulley 32, thereby preventing slack from occurring. As shown in FIGS. 2, 3 and 6, the second pressure mechanism 34 has a left pressure roller 341, a right pressure roller 342, a support plate 343, and the above-mentioned base block 334.

[0036] The support plate 343 has the same structure as the support plate 333 described above, and is supported by the base block 334 with its longitudinal direction facing diagonally upward and rearward. The support plate 343 supports the left pressure roller 341 and the right pressure roller 342 concentrically and rotatably on the left and right surfaces of the upper end portion thereof. The support plate 343 is disposed such that the left pressure roller 341 and the right pressure roller 342 abut against the outer surface of the belt extending between the guide frame 29 and the second pulley 32 from above the rear portion.

[0037] The support plate 343 also has an elongated hole, and the support plate 343 can be moved along the elongated hole. This makes it possible to adjust the pressure contact force of the left pressure roller 341 and the right pressure roller 342 against the belt stretched around the second pulley 32. Therefore, the tension of the belt passing between the guide frame 29 and the second pulley 32 can be adjusted.

[0038] The left pressure roller 341 and the right pressure roller 342 have the same outer diameter, and are supported rotatably about the same axis along the left-right direction by a support plate 343. In addition, the left pressure roller 341 and the right pressure roller 342 each have a width twice or more that of each of the lower belts 21-24. This allows the left pressure roller 341 to come into contact with both the rear left lower belt 21 and the front left lower belt 22 that are stretched between the guide frame 29 and the second pulley 32 . Similarly, the right pressure roller 342 can be brought into contact with either the front right lower belt 23 or the rear right lower belt 24 stretched between the guide frame 29 and the second pulley 32 .

[0039] The left pressure roller 331 of the first pressure mechanism 33 and the left pressure roller 341 of the second pressure mechanism 34 can both be brought into contact with the rear left lower belt 21 and the front left lower belt 22. Similarly, the right pressure roller 332 of the first pressure mechanism 33 and the right pressure roller 342 of the second pressure mechanism 34 can both be brought into contact with the front right lower belt 23 and the rear right lower belt 24. Therefore, regardless of whether each of the lower belts 21 to 24 is stretched around the first pulley 31 or the second pulley 32, tension is applied by either the first pressure mechanism 33 or the second pressure mechanism .

[0040] FIG. 6 shows the state in which the front left lower belt 22 and the front right lower belt 23, which are fed on the front side of the needle drop position, are hung around the first pulley 31, and the rear left lower belt and the rear right lower belt 21, 24, which are fed on the rear side, are hung around the second pulley 32. FIG. 7 shows the state in which the rear left lower belt 21 and the front left lower belt 22, which are fed to the left of the needle drop position, are hung on the first pulley 31, and the front right lower belt 23 and the rear right lower belt 24 are hung on the second pulley 32.

[0041] The lower belts 21 to 24 can be easily removed from the pulleys 31 and 32 and replaced by loosening the bolts and moving the pressure rollers 331, 332, 341, and 342 backward. Therefore, sewing in the hanging state of FIG. 6 and sewing in the hanging state of FIG. 7 can be easily selected.

[0042] For example, in the passing state of FIG. 6 (front and rear differential feed state), it is possible to perform so-called shirring stitches in which the front side of the needle drop position is fed faster than the rear side. In the front-rear differential feed state, the needle can be fed slower on the front side than on the rear side of the needle drop position to perform sewing with tension applied to the workpiece.

[0043] In the crossover state of FIG. 7 (left and right differential feed state), if the left side is fed quickly, a curved stitch that curves to the right can be made, and if the right side is fed quickly, a curved stitch that curves to the left can be made. In addition, since the curvature can be changed according to the difference in speed (difference in conveying amount) between the left and right sides, it is possible to sew a variety of curved lines.

[0044] [Fabric holding mechanism] Fig. 8 is a perspective view of the presser mechanism 70 and its periphery as a presser mechanism that presses down the sewing material on the needle plate 101 from above, Fig. 9 is a rear view, and Fig. 10 is a right side view. Note that Fig. 8 omits the illustration of the positioning ruler 50 and its support mechanism 53, which will be described later.

[0045] The cloth presser mechanism 70 includes a presser foot 71, a presser bar 72, a mounting base 74, a presser motor 73 (see FIG. 11), and a height sensor 762 (see FIG. 11) as a presser height detector. The presser bar 72 is disposed adjacent to the front of the needle bar 12 and is supported within the sewing machine arm portion 113 so as to be vertically movable along the vertical direction.

[0046] The upper end of the presser bar 72 is pressed downward by a presser spring (not shown) inside the sewing machine arm portion 113. The amount of expansion and contraction of the presser spring can be adjusted by a presser motor, the amount of movement of which can be controlled as desired. Therefore, by controlling the presser motor, the presser pressure of the presser foot 71 can be set as desired. The presser motor also provides a lifting operation for switching the presser foot 71 between a presser height at which the presser foot 71 presses down on the workpiece on the needle plate 101 and a release height at which the presser foot 71 is spaced upward.

[0047] In addition, a height sensor 762 for detecting the height of the presser bar 72 is provided together with the presser bar 72. Therefore, after the presser pressure of the presser foot 71 is set to a specified value, if the height of the presser foot 71 changes due to a change in the thickness of the material to be sewn, the presser motor is controlled so that the amount of expansion and contraction of the presser spring does not change, thereby making it possible to maintain the presser pressure at a constant set value.

[0048] The presser foot 71 is attached to the lower end of the presser bar 72 via a mounting base 74. The mounting base 74 is a block with horizontal and flat upper and lower surfaces. The mounting base 74 has an insertion hole formed therethrough from top to bottom, into which the presser bar 72 can be inserted. The mounting base 74 is fixed to the lower end of the presser bar 72 by, for example, fastening with screws. Further, a lower end of a link member 474 of the upper feed mechanism 40 (described later) is connected to the front end of the mounting base 74 so as to be rotatable about an axis extending in the left-right direction.

[0049] The presser foot 71 is disposed above the composite opening 102 of the needle plate 101. The presser foot 71 presses down the workpiece from above, and transmits the conveying force of the lower belts 21-24 appropriately to the workpiece. The presser foot 71 also supports the upper left belt 41 and the upper right belt 42 of the upper feed mechanism 40 via belt guides 43, 44 so that they can be conveyed. The presser foot 71 also has the function of pressing the upper belts 41, 42 against the workpiece, and transmitting the conveying force appropriately to the workpiece.

[0050] As shown in FIGS. 8 and 9, the presser foot 71 has a bottom plate 711 that presses down on the workpiece from above, and a connecting portion 712 that is attached to the lower end of the presser bar 72.

[0051] The bottom plate 711 has a smooth bottom surface and an upstream side (rear end) in the cloth feeding direction that is curved upward to form a so-called boat shape. The connecting part 712 is erected on the upper surface of the front end part of the bottom plate 711, and is connected to the bottom plate 711 so as to be able to swing somewhat around an axis along the left-right direction. An upper part of the connecting part 712 abuts on the bottom surface of the mounting base 74 and is fixed to the left side surface by, for example, screws. The connecting part 712 may be joined to the mounting base 74 by welding or the like, or the connecting part 712 and the mounting base 74 may be configured as a single integrated member.

[0052] [Upper feed mechanism] As shown in Figures 1, 2, 8 and 9, the upper feed mechanism 40 includes an upper left belt 41 and an upper right belt 42 as conveying belts, the left and right belt guides 43, 44 mentioned above, an upper left motor 45 which serves as a drive source for feeding the upper left belt 41, an upper right motor 46 which serves as a drive source for feeding the upper right belt 42, and a guide mechanism 47 which guides each of the upper belts 41, 42 from each of the upper motors 45, 46 to the presser foot 71.

[0053] The left and right belt guides 43, 44 are provided on the left and right sides of the presser foot 71. The belt guides 43 and 44 are rotatably attached to the left and right side surfaces of the lower part of the connecting portion 712 of the presser foot 71 by means of pivots extending in the left-right direction.

[0054] In a side view, each of the belt guides 43, 44 has a front end that extends obliquely upward toward the front, a rear end that is closest to the needle plate 101, and a rear end that rises obliquely upward toward the rear. Each of the belt guides 43, 44 is provided at its rear end with a feed roller 432, 442 that can rotate about a shaft extending in the left-right direction. The left and right endless annular upper belts 41, 42 are guided to pass between the left and right belt guides 43, 44 and the side surfaces of the presser foot 71. That is, the left and right upper belts 41, 42 are folded back downward from above the feed rollers 432, 442 along the rear outer periphery, and are guided to proceed forward along the portion of each belt guide 43, 44 that is closest to the needle plate 101, and then pass through in an obliquely upper-front direction. As each upper belt 41, 42 proceeds forward along the portion of each belt guide 43, 44 that is closest to the needle plate 101, it abuts against the workpiece on the needle plate 101 and feeds it forward. In addition, the contact position of the upper left belt 41 with the workpiece overlaps the contact position of the front left lower belt 22 with the workpiece in a plan view, and the workpiece is fed so as to be sandwiched between these belts. Similarly, the contact position of the upper right belt 42 with the workpiece overlaps the contact position of the front right lower belt 23 with the workpiece in a plan view, and the workpiece is fed so as to be sandwiched between these belts.

[0055] As described above, each of the belt guides 43, 44 is pivotally supported by the presser foot 71 via a support shaft (not shown) extending in the left-right direction. One end of the tension springs 433, 443 is connected to shafts 434, 444 provided at the front end of each of the belt guides 43, 44. The other end of each of the tension springs 433, 443 is connected to shafts 745, 746 provided on the left and right side portions of the mounting base 74, respectively, and applies upward tension to the front end of each of the belt guides 43, 44. As a result, the rear end sides of the belt guides 43, 44 are urged to rotate downward, and a pressing force is applied to the upper belts 41, 42 moving forward along the portion closest to the needle plate 101 toward the needle plate 101. As a result, a pressing force is applied to the upper belts 41, 42 against the workpiece on the needle plate 101.

[0056] In addition, since the rear end portions of the belt guides 43, 44 are pressed against the workpiece on the needle plate 101, the belt guides 43, 44 rotate about their pivots in response to changes in the thickness of the workpiece, causing changes in the height of the rear end portions. 10 and 11, in the sewing machine 100, the distance between the shafts 434, 444 and the shafts 745, 746 located at both ends of the tension springs 433, 443 of the belt guides 43, 44 is detected by the left and right potentiometers 48, 49. By detecting the left and right potentiometers 48, 49, it is possible to detect the change in height (up-down position) of the rear end portions of the belt guides 43, 44 caused by the rotation of the belt guides 43, 44.

[0057] The left and right upper motors 45, 46 are motors whose rotation speed can be controlled, such as a DC motor, an AC motor, or a stepping motor. The upper left motor 45 is supported on the front side of the left end of the sewing machine arm portion 113 via a motor bracket 451 with the output shaft facing leftward. The upper right motor 46 is supported above the upper left motor 45 via a motor bracket 451 on the front side of the left end of the sewing machine arm portion 113 with its output shaft facing leftward.

[0058] A motor pulley 452 is attached to the output shaft of the upper-left motor 45, and one end of the upper-left belt 41 is wound around the motor pulley 452. Further, a motor pulley 462 is provided on the output shaft of the upper right motor 46, and one end of the upper right belt 42 is wound around the motor pulley 462.

[0059] The upper-left belt 41 is an endless loop, and one end of the loop is stretched out and hung around the motor pulley 452 of the upper-left motor 45 , and the other end is hung around the feed roller 432 of the belt guide 43 . The upper right belt 42 is also an endless loop, and one end of the loop is stretched out and hung around the motor pulley 462 of the upper right motor 46, and the other end is hung around the feed roller 442 at the rear end of the belt guide 44 mentioned above.

[0060] The path of the upper left belt 41 from the motor pulley 452 to the feed roller 432 and the path of the upper right belt 42 from the motor pulley 462 to the feed roller 442 overlap each other when viewed from the left-right direction, except for the periphery of the motor pulleys 452, 462. The upper right belt 42 is disposed on the right side of the upper left belt 41.

[0061] The guide mechanism 47 guides the upper left belt 41 and the upper right belt 42 along the respective paths described above. The guide mechanism 47 has a pair of first tension rollers 471 lined up on the left and right, a pair of second tension rollers 472 lined up on the left and right, a guide arm 475 consisting of upper and lower link members 473, 474, and a plurality of guide rollers 476 rotatably mounted at various portions on the path of each of the upper belts 41, 42.

[0062] The pair of first tension rollers 471 are disposed below the motor pulley 452. The pair of second tension rollers 472 are disposed between the motor pulley 452 and the pair of first tension rollers 471. The pair of first tension rollers 471 is rotatable about an axis along the left-right direction and has a wide axial width. The pair of first tension rollers 471 press against both the upper left belt 41 and the upper right belt 42 from the outside to apply inward tension to them. The pair of second tension rollers 472 is rotatable about an axis along the left-right direction and has a narrow axial width. The pair of second tension rollers 472 presses against only the upper right belt 42 from the inside to apply outward tension. In addition, the upper right belt 42 is expanded on both the front and rear sides by the pair of second tension rollers 472, so that interference with the motor pulley 452 located midway along the path can be avoided.

[0063] An upper link member 473 constituting a guide arm 475 has one end connected to a lower end of the motor bracket 451 so as to be rotatable about an axis along the left-right direction. The other end of the upper link member 473 is connected to one end of the lower link member 474 so as to be rotatable about an axis along the left-right direction. Furthermore, as described above, the other end of the lower link member 474 is connected to the front end of the mounting base 74 so as to be rotatable about an axis extending in the left-right direction.

[0064] At the connection between the upper link member 473 and the lower link member 474, a guide roller 476 is provided that contacts the inside of the loop from the front side for the upper left belt 41 and the upper right belt 42, and a guide roller (not shown) is provided that contacts the outside of the loop from the front side. As a result, the left and right upper belts 41, 42 are transported along a path along the upper link member 473 and a path along the lower link member 474. Therefore, even if the presser foot 71 rises and falls due to a change in thickness of the sewing material or unevenness, causing a change in the bending angle between the upper link member 473 and the lower link member 474, the left and right upper belts 41, 42 maintain a path along the upper link member 473 and a path along the lower link member 474. Therefore, the path length of each upper belt 41, 42 is maintained constant, and fluctuations in tension can be suppressed.

[0065] [Positioning ruler] In FIG. 9, reference numeral 50 denotes a positioning ruler, and reference numeral 53 denotes a support mechanism thereof. The positioning ruler 50 is used to position the side edge of the workpiece in the left and right direction when sewing while maintaining the side edge of the workpiece at a fixed distance (edge ​​width) from the needle drop position. The positioning ruler 50 has an abutment plate 51 against which the side end (the right end in this embodiment) of the workpiece on the needle plate 101 abuts, and a connecting portion 52 that connects the abutment plate 51 to a support mechanism 53. The abutment plate 51 is made of a flat plate that is aligned in the front-to-rear and up-down directions, and the right end of the workpiece abuts against the left surface.

[0066] The support mechanism 53 includes a holding shaft 54 ​​that holds the positioning ruler 50, a cylindrical body 55 through which the holding shaft 54 ​​is inserted, an air cylinder that raises and lowers the positioning ruler 50 to switch it between an in-use position on the needle plate 101 and a non-use position retracted upward, and a position adjustment motor 57 (see Figure 11) that moves and positions the positioning ruler 50 in the left-right direction via the holding shaft 54.

[0067] [Evacuation mechanism] Reference numeral 60 shown in FIGS. 8 to 10 denotes a retraction mechanism for maintaining the right belt guide 44 in the retracted position when the positioning ruler 50 is used. When the adjusted edge width is small, the abutment plate 51 is disposed close to the needle drop position. In this case, since there is a risk that the rear end of the right-side belt guide 44 may interfere with the abutment plate 51, the belt guide 44 is rotated about the support shaft to move the rear end upward. The retraction mechanism 60 is a mechanism that holds the rear end of the belt guide 44 in an upward retracted state.

[0068] The retraction mechanism 60 has a holding member 61 whose upper end is supported by a support shaft 62 along the left-right direction. When the holding member 61 is rotated, a recess 611 formed in the lower end can fit and hold the shaft portion 444 on the front end side that moves downward when the rear end of the belt guide 44 is retracted upward. Reference numeral 612 denotes an operating portion for rotating the holding member 61. This allows the holding member 61 of the retracting mechanism 60 to hold the rear end of the belt guide 44 in a retracted upward state. In addition, the symbol 63 denotes a torsion coil spring, which urges the lower end of the holding member 61 in a direction to rotate forward, and when the belt guide 44 is not being held, the lower end of the holding member 61 is retracted forward so as not to interfere with the belt guide 44.

[0069] [Use of sewing machine] The sewing machine 100 having the above configuration is capable of performing sewing with upper belt feed and lower belt feed. In this case, the lower feed mechanism 20 can perform sewing by feeding the front side and rear side of the needle hole 13 at different speeds by looping the lower belts 21 to 24 in the manner shown in FIG. In addition, the lower feed mechanism 20 can perform sewing by feeding the left and right sides of the needle hole 13 at different speeds by looping the lower belts 21 to 24 in the manner shown in FIG.

[0070] On the other hand, when sewing the right edge of the workpiece, the front end of the right belt guide 44 is pressed down to move it from the feed position to the retracted position and the retracted position is maintained by the retraction mechanism 60. Then, the actuator of the support mechanism 53 of the positioning ruler 50 is driven to move the positioning ruler 50 from the non-use position to the use position. As a result, the sewing work is fed while sewing so that the right end of the work is always in contact with the left surface of the abutment plate 51 of the positioning ruler 50, thereby sewing with the desired edge stitch width.

[0071] [Sewing machine control system] FIG. 11 is a block diagram showing the control system of the sewing machine 100. As shown in the figure, the sewing machine 100 is equipped with a control device 90 that controls the operation of each component. The sewing machine motor 16, the presser motor 73, the first motor 25, the second motor 26, the upper left motor 45, the upper right motor 46, and the position adjustment motor 57 are connected to this control device 90 via their respective motor drive circuits 16a, 73a, 25a, 26a, 45a, 46a, and 57a. Encoders 161, 732, 251, 261, 453, 461, 571 for detecting the number of rotations are provided in association with the sewing machine motor 16, the presser motor 73, the first motor 25, the second motor 26, the upper left motor 45, the upper right motor 46, and the position adjustment motor 57. These encoders 161, 732, 251, 261, 453, 461, 571 are also connected to the control device 90 via the motor drive circuits 16a, 73a, 25a, 26a, 45a, 46a, 57a.

[0072] In addition, the control device 90 is connected to an electromagnetic valve 58 via a drive circuit 58a, which operates a position switching air cylinder that switches the positioning ruler 50 between the use position and the non-use position.

[0073] The control device 90 includes a CPU 91, a ROM 92, a RAM 93, and a data memory 94, and executes various operational controls described below. The ROM 92 stores the basic system program. Furthermore, various data and programs, which will be described later, are stored in the data memory 94. The data memory 94 is made up of a non-volatile semiconductor memory such as a flash memory, an EEPROM, or an EPROM, but a storage such as an HDD may also be used. The CPU 91 executes various programs in the ROM 92 and the data memory 94. The RAM 93 is a memory that serves as a working area for the CPU 91.

[0074] In addition, an operation input unit 96 serving as a setting input device is connected to the control device 90 via an interface 96a. The operation input unit 96 includes an input screen 961, which displays information required for inputting various settings. The operation input unit 96 is configured as a so-called touch panel or touch screen in which a touch sensor is provided on the input screen 961. However, the display screen and the operation input unit may be configured separately and independently.

[0075] A pedal 95, which is depressed to start and stop sewing, increase and decrease the sewing speed, and input other commands, is also connected to the control device 90 via an interface 95a. Furthermore, the control device 90 is connected to a height sensor 762 that detects the height of the presser foot 71 and the above-mentioned left and right potentiometers 48, 49 via interfaces 762a, 48a, 49a.

[0076] [Control based on detection of the height of the feed position of the upper belts on the left and right] The control described below is suitable for performing sewing in which the lower belts 21-24 of the lower feed mechanism 20 are looped around in the manner shown in FIG. 7 and the left and right sides of the needle hole 13 are fed at different speeds.

[0077] The height sensor 762, which detects the height of the presser foot 71, and the left and right potentiometers 48, 49 function as detection units that detect the height of the workpiece at the feed position of the upper left belt 41 and the height of the workpiece at the feed position of the upper right belt 42, relative to the needle plate. The left and right potentiometers 48, 49 function as detection units that detect the height of the workpiece at the feed position of the upper left belt 41 and the height of the workpiece at the feed position of the upper right belt 42 relative to the presser foot. The left and right potentiometers 48, 49 function as detection units that detect the difference in height between the workpiece at the feed position of the upper left belt 41 and the workpiece at the feed position of the upper right belt 42.

[0078] The "height of the workpiece at the feed position" refers to the height of the position where the left and right upper belts 41, 42 contact the workpiece near the rear ends of the left and right belt guides 43, 44. The belt guides 43, 44 are pressed against the workpiece at this position, so the height of the workpiece can be obtained by determining the height of this position.

[0079] Further, here, "the height of the workpiece at the feed position" refers to the height as seen from the presser foot 71 which serves as a support member supporting the left and right belt guides 43, 44. However, the "height of the workpiece at the feed positions of the left and right upper belts 41, 42" is not limited to the above, and may be, for example, the height from the upper surface of the needle plate 101.

[0080] As described above, the left and right potentiometers 48, 49 detect the distance between the shafts 434, 444 located at the front ends of the belt guides 43, 44 and the shafts 745, 746 facing the shafts 434, 444 at an obliquely upper rear position. There is a correlation between this distance and the height of the workpiece at the feed positions of the left and right upper belts 41, 42. Therefore, a height table 941 indicating this correlation is prepared in the data memory 94. The CPU 91 of the control device 90 can obtain "the height of the sewing workpiece at the feed positions of the left and right upper belts 41, 42" by referring to the height table 941 based on the detection values ​​of the potentiometers 48, 49.

[0081] (1) As described above, the CPU 91 of the control device 90 can obtain "the height of the workpiece at the feed positions of the left and right upper belts 41, 42" from the detection values ​​of the potentiometers 48, 49. In this case, "the height of the workpiece at the feed positions of the left and right upper belts 41, 42" is defined as "the height based on the presser feet of the left and right upper belts 41, 42." (2) Furthermore, the CPU 91 can obtain the “difference in height of the sewing workpiece at the feed positions of the left and right upper belts 41, 42” from the difference in the upward movement amounts of the left and right belt guides 43, 44. (3) Furthermore, the CPU 91 can obtain the height of the presser foot 71 from the top surface of the needle plate from the detection value of the height sensor 762, and can obtain the "height of the workpiece at the feed positions of the left and right upper belts 41, 42" as viewed from the needle plate 101 by adding the "height of the workpiece at the feed positions of the left and right upper belts 41, 42" to the height of the presser foot 71 from the top surface of the needle plate. In this case, the "height of the workpiece at the feed positions of the left and right upper belts 41, 42" is defined as the "height of the left and right upper belts 41, 42 relative to the needle plate."

[0082] The left and right upper belts 41, 42 have individual feed pitches set, and by controlling the operation of the left and right upper motors 45, 46, transport is intermittently performed by the set feed pitch for each stitch. In response to this, the CPU 91 determines the value of one of the following: (1) "the height of the left and right upper belts 41, 42 based on the presser feet," (2) "the difference in height of the sewn workpiece at the feed positions of the left and right upper belts 41, 42," or (3) "the height of the left and right upper belts 41, 42 based on the needle plate," and executes operational control to make corrections to the drive of the left and right upper motors 45, 46 based on the determined value.

[0083] When the CPU 91 acquires (1) "the height of the left and right upper belts 41, 42 based on the presser feet", the CPU 91 performs the following operation control on the left and right upper motors 45, 46. When the upward movement of the feed position due to the rotation of the belt guides 43, 44 increases, the tension of the tension springs 433, 443 increases, and the pressure when pressed by the belt guides 43, 44 increases. As a result, the resistance force of the conveyance of the left and right upper belts 41, 42 increases, so a correction is made to increase the feed speed or increase the torque when driven while maintaining the operating amount of one feed pitch for the upper motors 45, 46. In this case, a feed table 942 that defines the correspondence between the speed correction values ​​or torque correction values ​​of the upper motors 45, 46 and "the height of the left and right upper belts 41, 42 based on the presser feet" is prepared in the data memory 94. The speed correction values ​​and torque correction values ​​may be, for example, speed increase / decrease magnification values ​​or torque increase / decrease magnification values. Then, when the CPU 91 acquires the "height of the left and right upper belts 41, 42 based on the presser feet" for each of the left and right sides, it refers to the feed table 942 and performs operational control to individually correct the feed speed or torque for driving the left and right upper motors 45, 46.

[0084] Furthermore, when the CPU 91 acquires (2) "the difference in height of the sewing workpiece at the feed positions of the left and right upper belts 41, 42," the CPU 91 performs the following operation control on the left and right upper motors 45, 46. When the difference in height between the upper belts 41, 42 between the left and right belt guides 43, 44 becomes large, the tension of one of the tension springs 433, 443 increases, increasing the pressure applied by the corresponding belt guide 43, 44 when pressed against the belt, thereby increasing the resistance to conveyance. Therefore, while maintaining the amount of movement for one feed pitch, the CPU 91 makes a correction to increase the feed speed or increase the torque when driven for the upper motor 45, 46 which has a higher feed position, and makes a correction to decrease the feed speed or decrease the torque when driven for the upper motor 45, 46 which has a lower feed position. In this case, a feed table 942 that defines the correspondence between the height difference of the feed position and the speed increase / decrease value or torque increase / decrease value of the upper motors 45, 46 is prepared in the data memory 94. The speed increase / decrease value or torque increase / decrease value may be, for example, a speed increase / decrease magnification value or a torque increase / decrease magnification value. When the CPU 91 acquires the height difference between the feed positions of the upper belts 41, 42 of the left and right belt guides 43, 44, it refers to the feed table 942 and executes operation control to drive the left and right upper motors 45, 46 by increasing or decreasing the speed or increasing or decreasing the torque. In this case, the speed or torque of the upper motors 45, 46 is increased and the other is decreased as an example of control, but it is also possible to increase the speed or torque only for the upper motor 45, 46 where the feed position is higher, and not make any correction for the upper motor 45, 46 where the feed position is lower.

[0085] When the CPU 91 acquires (3) "the heights of the left and right upper belts 41, 42 with respect to the needle plate", the CPU 91 performs the following operation control on the left and right upper motors 45, 46. The "height of the left and right upper belts 41, 42 with respect to the needle plate" indicates the thickness of the workpiece. When the workpiece is thick, depending on the material of the workpiece, for example, when the workpiece is flexible, the feed rate of the workpiece may decrease. Therefore, when the thickness of the sewing material increases, a correction is made by adding a feed amount to the feed pitch set for one feed of the upper motor 45 or 46. In this case, a feed table 942 that defines the correspondence relationship between the "heights of the left and right upper belts 41, 42 with respect to the needle plate" and the additional values ​​of the feed amounts of the upper motors 45, 46 is prepared in the data memory 94. The additional value of the feed amount may be, for example, a value of an increase magnification of the feed amount. Then, when the CPU 91 acquires the "height of the left and right upper belts 41, 42 relative to the needle plate" for the left and right belt guides 43, 44, it refers to the feed table 942 and executes operation control for correcting the set feed pitch and driving the left and right upper motors 45, 46, respectively.

[0086] In addition, the sewing machine 100 may be configured to obtain only one of (1) "the height of the left and right upper belts 41, 42 based on the presser feet," (2) "the difference in height of the workpiece at the feed positions of the left and right upper belts 41, 42," or (3) "the height of the left and right upper belts 41, 42 based on the needle plate," and only control the operation of the left and right upper motors 45, 46 corresponding to that one. Also, the above (1) to (3) are acquired, but only those of the corresponding operation controls selected through the operation input unit 96 may be performed. In this case, the operation input unit 96 functions as a selection setting unit. Furthermore, two or more of the above (1) to (3) may be acquired to control the operation of all of the corresponding left and right upper motors 45, 46.

[0087] In addition, (1) when the "height of the left and right upper belts 41, 42 based on the presser feet of the left and right upper belts 41, 42" is obtained, the left and right upper motors 45, 46 are corrected to increase the feed speed or torque during driving, but instead of or in parallel with these, operational control may be executed to correct and drive the motors to increase the set feed pitch. In that case, a feed table may be prepared in the data memory 94 that defines the correspondence relationship between the "height of the left and right upper belts 41, 42 based on the presser feet" and the additional value of the feed amount of the upper motors 45, 46. In this case, the additional value of the feed amount may be, for example, a value of the feed amount increase magnification.

[0088] In addition, (2) when "the difference in height of the sewn workpiece at the feed positions of the left and right upper belts 41, 42" is obtained, the left and right upper motors 45, 46 are corrected to increase the feed speed or the torque during driving, but instead of or in parallel with these, operation control may be executed to correct and drive the motors to increase the set feed pitch. In this case, a feed table that defines the correspondence relationship of the additional value of the feed amount of the upper motors 45, 46 to "the difference in height of the sewn workpiece at the feed positions of the left and right upper belts 41, 42" may be prepared in the data memory 94. In this case, the additional value of the feed amount may be, for example, a value of the increase magnification of the feed amount.

[0089] In addition, (3) when the "height of the left and right upper belts 41, 42 with respect to the needle plate" as viewed from the needle plate 101 is obtained, the left and right upper motors 45, 46 are corrected to increase the set feed pitch and driven, but instead of or in parallel with this, a correction may be made to increase the feed speed or to increase the torque during driving. In this case, a feed table that defines the correspondence between the speed correction value or torque correction value of the upper motors 45, 46 and the "height of the left and right upper belts 41, 42 with respect to the needle plate" may be prepared in the data memory 94. In this case, the speed correction value may also be a value of the speed increase / decrease rate. Also, the torque correction value may also be a value of the torque increase rate.

[0090] In either case, various tables used for correcting the driving of the left and right upper motors 45, 46 in response to the acquisition of the above (1) to (3) may be created by input from the operation input unit 96. In this case, the operation input unit 96 functions as a numerical value setting unit.

[0091] In addition, when the CPU 91 obtains (1) "the height of the left and right upper belts 41, 42 based on the presser feet," (2) "the difference in height of the sewn workpiece at the feed positions of the left and right upper belts 41, 42," or (3) "the height of the left and right upper belts 41, 42 based on the needle plate," the CPU 91 performs a correction for the upper motor 45 or 46 that drives the upper belt 41 or 42 that has a higher feed position by increasing the feed speed, increasing the torque during driving, or adding the feed amount, but this is not limited to the above. For example, depending on the type of sewing material and the support structure of the upper belts 41, 42, the upper motor 45 or 46 driving the upper belt 41 or 42, which lowers the height of the feed position, may be corrected by increasing the feed speed, increasing the driving torque, or adding the feed amount. In these cases, it is desirable to prepare various necessary tables in the data memory 94. In addition, the sewing machine 100 may be configured to be able to select whether to make a correction by increasing the feed speed, increasing the torque during driving, or adding the feed amount depending on whether the height of the feed position is high or low.

[0092] [Technical Effects of the Invention Embodiments] The sewing machine 100 is equipped with left and right potentiometers 48, 49 and a height sensor 762 as detection sections, and based on the detection of these detection sections, the control device 90 controls the adjustment of the drive of the feed of the conveyor belts 41, 42 by the left and right upper motors 45, 46 of the upper feed mechanism 40. As a result, if there is a difference in thickness of the material to be sewn on the left and right sides of the needle drop position, the conveying operation by the upper feed mechanism 40 can be adjusted, making it possible to perform appropriate feeding.

[0093] In addition, the control device 90 adjusts the feed amount (feed pitch) of one or both of the upper left belt 41 and the upper right belt 42 based on the detection of the above-mentioned detection unit. This makes it possible to suppress the fluctuation in the feed amount between the left and right sides caused by the difference in height. In particular, the control device 90 controls the feed amount of the left or right upper belt 41, 42 which has the higher height of the sewn material at the feed position, thereby making it possible to suppress a reduction in the feed amount that may occur due to an increase in the thickness of the sewn material. In addition, the control device 90 controls the feed amount of one of the left and right upper belts 41, 42 which has a lower height of the sewn material at the feed position, thereby making it possible to suppress a reduction in the feed amount that may occur due to a decrease in the thickness of the sewn material, which may occur depending on the type of sewn material.

[0094] In addition, the control device 90 adjusts the feed speed of one or both of the upper left belt 41 and the upper right belt 42 based on the detection of the above-mentioned detection unit. This makes it possible to suppress fluctuations in the feed speeds on the left and right sides due to differences in elevation. In particular, the control device 90 controls the feed speed of one of the left and right upper belts 41, 42, whichever has the higher height of the sewn material at the feed position, to be faster, thereby making it possible to suppress a reduction in the feed speed that may occur due to an increase in the thickness of the sewn material. In addition, the control device 90 controls the feed speed of one of the left and right upper belts 41, 42, which has a lower height of the sewn material at the feed position, to be faster, thereby making it possible to suppress a reduction in the feed speed that may occur due to a decrease in the thickness of the sewn material, which may occur depending on the type of sewn material.

[0095] In addition, the control device 90 performs control to adjust the torque of one or both of the motor that feeds the upper left belt 41 and the left and right upper motors 45, 46 that feed the upper right belt 42 based on the detection of the above-mentioned detection unit. This makes it possible to suppress fluctuations in the torque of the left and right feeds caused by differences in elevation. In particular, the control device 90 controls the torque of the upper motor 45 or 46 which feeds the upper belt 41, 42 which has the higher height of the sewn material at the feed position, thereby making it possible to suppress a reduction in the feed torque that may occur due to an increase in the thickness of the sewn material. In addition, the control device 90 controls the torque of the upper motor 45 or 46 that feeds the upper belt 41, 42 which has the lower height of the sewn material at the feed position, out of the left and right upper belts 41, 42, thereby making it possible to suppress a reduction in the feed torque that may occur due to a decrease in the thickness of the sewn material, which may occur depending on the type of sewn material.

[0096] [others] Above, each embodiment of the present invention has been described. However, the present invention is not limited to the above-mentioned embodiments. For example, in the embodiments, a component integrally formed from a single member may be replaced with a component divided into a plurality of members and connected or fixed to each other. Also, a component formed by connecting a plurality of members may be replaced with a component integrally formed from a single member. In addition, the details shown in the embodiments can be appropriately changed without departing from the spirit of the invention.

[0097] For example, the feed position detected by the detection unit is not limited to the position where the upper belts 41, 42 abut on the left and right belt guides 43, 44, but also includes the surrounding area, such as the upstream side or downstream side of the abutment position, where there is no significant difference in the detection values ​​(the range that can be considered to be substantially the same).

[0098] Furthermore, the detection section for detecting the height of the workpiece at the feed position of the left and right upper belts 41, 42 is not limited to the above configuration, and any detection means capable of detecting the height of the workpiece at the feed position can be used. For example, optical distance sensors 48A, 49A may be used as shown in Fig. 12. In this case, it is preferable that the distance sensors 48A and 49A detect the distance from above immediately upstream of the contact position of the left and right upper belts 41, 42 on the sewing workpiece. It is preferable that the distance sensors 48A and 49A are provided at positions where the height does not change during sewing, for example, above the detection position and below the sewing machine arm portion 113. In this case, each of the distance sensors 48A and 49A can detect, by itself, the "height of the workpiece relative to the needle plate at the feed positions of the left and right upper belts 41, 42" as viewed from the needle plate 101, and it is possible to obtain the thickness of the workpiece at each detection position.

[0099] As the detection section, instead of the potentiometers 48, 49 for detecting the center distance between the left and right belt guides 43, 44, a rear sensor or a magnetic sensor may be used for detecting the center distance. As the detection section, a rotary potentiometer or encoder for detecting the angle of the left and right belt guides 43, 44 around the support shaft 431 may be used.

[0100] In addition, in the above-mentioned sewing machine 100, as shown in Fig. 4, the needle hole 13 is provided in the needle hole member 30 that moves up and down relative to the needle plate 101 at the same cycle as the sewing needle 11, but the present invention is not limited to this. For example, as shown in Fig. 13, the needle hole 13 may be formed directly penetrating the needle plate 101, and the needle hole 13 may be fixedly provided in a member that does not move up and down. [Explanation of symbols]

[0101] 11 Sewing Needle 12 Needle bar 13 Needle hole 16 Sewing machine motor 20 Lower feed mechanism 21 Rear left lower belt 22 Front left lower belt 23 Front right lower belt 24 Rear right lower belt 25 First Motor 26 Second Motor 40 Upper feed mechanism 41 Upper left belt 42 Upper right belt 43,44 Belt guide 433,443 Tension spring 434,444 Shaft 45 Upper left motor 46 Top Right Motor 48,49 Potentiometer (detection part) 48A, 49A Distance sensor (detection part) 70 Cloth presser mechanism 71 Presser foot 762 Height sensor (detection part) 90 Control device 91 CPU 94 Data Memory 941 Height Table 942 Feeding table 100 Sewing Machine 101 Needle plate

Claims

1. a needle up-down movement mechanism that moves the sewing needle up and down using a sewing machine motor; an upper feed mechanism that feeds the workpiece on the needle plate by individually contacting the conveyor belt from above on both the left and right sides of the needle drop position; a detection unit for detecting a height of the workpiece at a feed position of the left conveyor belt and a height of the workpiece at a feed position of the right conveyor belt, or detecting a difference therebetween; A control device that controls the operation of the needle up and down movement mechanism and the upper feed mechanism, The control device controls adjustment of the drive of the feed of the left and right conveyor belts of the upper feed mechanism based on the detection by the detection unit.

2. 2. The sewing machine according to claim 1, wherein the control device performs control to adjust the feed rate of one or both of the left and right conveyor belts based on the detection by the detection unit.

3. 3. The sewing machine according to claim 2, wherein the control device performs control so as to relatively increase the feed amount of one of the left and right conveyor belts which has a higher height of the sewing workpiece at the feed position.

4. 3. The sewing machine according to claim 2, wherein the control device performs control so as to relatively increase the feed amount of one of the left and right conveyor belts which has a lower height of the sewing workpiece at the feed position.

5. 2. The sewing machine according to claim 1, wherein the control device adjusts a feed speed of one or both of the left and right conveyor belts based on the detection by the detection unit.

6. 6. The sewing machine according to claim 5, wherein the control device controls the feed speed of one of the left and right conveyor belts, the one having a higher height of the sewing workpiece at the feed position, to be relatively faster.

7. 6. The sewing machine according to claim 5, wherein the control device controls the feed speed of one of the left and right conveyor belts, the one having a lower height of the sewing workpiece at the feed position, to be relatively faster.

8. The sewing machine according to claim 1, characterized in that the control device performs control to adjust the torque of one or both of the motor that feeds the left side conveyor belt and the motor that feeds the right side conveyor belt based on the detection of the detection unit.

9. 9. The sewing machine according to claim 8, wherein the control device performs control so as to relatively increase the torque of a motor that feeds one of the left and right conveyor belts, the motor being one that feeds the sewing workpiece at a higher height at the feed position.

10. 9. The sewing machine according to claim 8, wherein the control device performs control so as to relatively increase the torque of a motor that feeds one of the left and right conveyor belts, the motor being one that feeds the workpiece at a lower height at the feed position.

11. the detection unit is capable of detecting a height of the workpiece at a feed position of the left conveyor belt and a height of the workpiece at a feed position of the right conveyor belt based on a presser foot and a height of the workpiece at a feed position of the right conveyor belt, The sewing machine according to any one of claims 1 to 10, characterized in that the control device includes a selection setting unit that selects whether to adjust the drive of the feed of the left and right conveyor belts of the upper feed mechanism based on a height based on the presser foot, a height based on the needle plate, or a difference between the heights.

12. 9. The sewing machine according to claim 2, 5 or 8, wherein the control device includes a value setting unit for setting a value to be adjusted.

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