Sewing machine

Abstract

To stably deliver an object to be sewn.SOLUTION: A sewing machine 100 which includes a feeding device 40 for performing feeding of an object to be sewn by conveyor belts 41, 42 coming into contact with the object to be sewn includes: belt guides 43, 44 supported so as to oscillate by a support shaft 431 along a direction orthogonal to a feeding direction by a support member 71 above a needle plate 101; and feeding rollers 432, 442 provided at a rear end part of the belt guides 43, 44 and for folding back a belt in such a manner that the conveyance direction becomes the front side at the bottom part of the belt guides 43, 44. Further on the upstream side in the conveyance direction than the feeding rollers 432, 442, a conveyance path of the conveyor belts 41, 42 is formed so as to pass further on the lower side than the support shaft 431 of the belt guides 43, 44.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present invention relates to a sewing machine that uses a belt feed. [Background technology]

[0002] In conventional sewing machines having a belt that contacts the workpiece on the needle plate from above to feed it, a belt guide that transports the belt over the workpiece on the needle plate is supported so that it can swing by an axis that runs in the left-right direction relative to a support member. When the downstream side of this belt guide in the feed direction is considered to be the front, the rear end side swings up and down, pressing against the belt passing over the rear end to impart a conveying force to the workpiece (see, for example, Patent Document 1).

[0003] The belt guide extends forward and backward, is supported at a longitudinal middle portion so as to be swingable, and has a roller at its rear end portion for guiding the belt. The belt is conveyed diagonally downward from the motor side, which serves as a driving source, passes through the roller at the rear end portion of the belt guide from top to bottom, is turned back, advances forward along the bottom portion of the belt guide, and then returns diagonally upward toward the front. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-221644 A Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, the belt guide is supported by the support member so as to be able to swing, and the belt passing over the rear end portion of the belt guide feeds the workpiece forward.

[0006] However, when attempting to reverse feed the sewn material using the above-mentioned belt feed sewing machine, the roller is pulled backward by the belt being transported in the reverse direction, causing the rear end of the belt guide to lift up, making it impossible to reverse feed properly and resulting in misaligned stitching or poor feeding.

[0007] An object of the present invention is to perform proper sewing. [Means for solving the problem]

[0008] The present invention relates to A sewing machine including a feed device that feeds a workpiece by a conveyor belt that contacts the workpiece, a belt guide supported by a support member above the needle plate so as to be swingable about a support shaft extending in a direction perpendicular to the feed direction; a guide portion provided at a rear end portion of the belt guide and configured to turn the conveyor belt so that the conveying direction is the front side at the bottom portion of the belt guide; Equipped with The conveying belt may be formed with a conveying path for passing below the support shaft of the belt guide, upstream of the guide portion in the conveying direction. Effect of the Invention

[0009] With the above-described configuration, the sewing machine of the present invention is able to suppress the lifting of the belt guide and perform proper sewing. [Brief description of the drawings]

[0010] [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. 13 is a left side view of the vicinity of the needle drop position in the upper feed mechanism. [Figure 10] 10 is a left side view of the upper feed mechanism shown in FIG. 9 with the left belt guide removed. [Figure 11] FIG. 4 is a perspective view of a shaft member that locks a tension spring. [Figure 12] 13 is a left side view of the vicinity of the presser foot in which the shaft member is attached in such a manner that the axial distance between the shaft portion to which both ends of the tension spring are connected and the locking shaft is long. FIG. [Figure 13] 13 is a left side view of the vicinity of the presser foot in which the shaft member is attached in such a manner that the axial distance between the shaft portion to which both ends of the tension spring are connected and the locking shaft is shortened. FIG. [Figure 14] FIG. 13 is a left side view of the belt guide and its surroundings in a comparative example in which the upper belt conveying path characteristic of the sewing machine of the present embodiment is not configured. [Figure 15] 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

[0011] [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.

[0012] 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, an upper feed mechanism 40, a presser mechanism 70 as a presser mechanism, and a shuttle mechanism. 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 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.

[0013] [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 .

[0014] [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. 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. Incidentally, the upper shaft and the crank mechanism are not shown in the figure since they are well known.

[0015] 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.

[0016] 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.

[0017] [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.

[0018] 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.

[0019] [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.

[0020] 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 .

[0021] The first and second motors 25, 26 are both motors whose operation amount can be arbitrarily controlled, such as a stepping motor or a servo motor. An encoder may be provided in each of the motors 25, 26. The first and second motors 25, 26 are arranged in a line up in front and rear, inside the right end of the sewing machine bed portion 111, with the output shaft 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 .

[0022] 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.

[0023] 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. This allows each of the lower belts 21 to 24 to be stretched over the first pulley 31 and the second pulley 32 by appropriately selecting them.

[0024] 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.

[0025] 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.

[0026] 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 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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 294a is set so that the outer surface of the lower rear right 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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 .

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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 .

[0041] 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 .

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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 sewn, and if the right side is fed quickly, a curved stitch that curves to the left can be sewn. 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.

[0046] [Fabric holding mechanism] FIG. 8 is a perspective view of the presser mechanism 70 which serves as a presser mechanism for pressing down the workpiece on the needle plate 101 from above.

[0047] The cloth presser mechanism 70 includes a presser foot 71, a presser bar 72, a mounting base 74, a presser motor (not shown), and a presser height detector (not shown). 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.

[0048] 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.

[0049] In addition, a presser height detector (not shown) 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 pressure can be maintained at a constant set value by controlling the presser motor so that the amount of expansion and contraction of the presser spring does not change.

[0050] 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.

[0051] 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 appropriately transmits the conveying force of the lower belts 21-24 to the workpiece. The presser foot 71 also supports the upper left belt 41 and the upper right belt 42 via the belt guides 43, 44 of the upper feed mechanism 40 so that they can be conveyed. That is, the presser foot 71 functions as a support member. The presser foot 71 also has the function of pressing the upper belts 41, 42 against the workpiece to appropriately transmit the conveying force to the workpiece.

[0052] As shown in FIG. 8, 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 .

[0053] 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.

[0054] [Upper feed mechanism] 9 is a left side view of the vicinity of the needle drop position in the upper feed mechanism 40, and FIG. 10 is a left side view of the upper feed mechanism 40 in FIG. 9 with the left belt guide 43 removed. As shown in Figures 1, 2, and 8 to 10, 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 that serves as a drive source for belt feed of the upper left belt 41, an upper right motor 46 that serves as a drive source for belt feed of the upper right belt 42, and a guide mechanism 47 that guides each of the upper belts 41, 42 from each of the upper motors 45, 46 to the presser foot 71.

[0055] 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 support shafts 431 extending in the left-right direction.

[0056] 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 is raised obliquely upward toward the rear. The left and right belt guides 43, 44 are symmetrical with respect to a plane extending along the front-rear and top-bottom directions.

[0057] As shown in FIG. 10, the left and right belt guides 43 and 44 are provided at their rear ends with feed rollers 432 and 442 as guides that can be rotated by shafts extending in the left-right direction. The left and right endless annular upper belts 41, 42 are transported from the obliquely upper front side of the belt guides 43, 44 toward the obliquely lower rear side of the belt guides 43, 44, and 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 outer periphery, and are guided to proceed forward along the portion of each belt guide 43, 44 closest to the needle plate 101, and then return in the obliquely upper front direction. As each upper belt 41, 42 proceeds forward along the portion of each belt guide 43, 44 closest to the needle plate 101, it abuts against the workpiece on the needle plate 101 and feeds it forward.

[0058] The left and right belt guides 43, 44 and the surrounding structures forming the transport paths of the left and right upper belts 41, 42 will be described in further detail. As shown in FIG. 10, on the left side surface (the surface facing the presser foot 71) of the right-side belt guide 44, a first guide piece 445 is erected toward the left, slightly forward of and slightly lower than the feed roller 442, in sliding contact from above with the upper right belt 42, which is transported upstream of the feed roller 442. In this specification, when the conveyance of each belt 21-24, 41, 42 is referred to as "upstream" or "downstream," it refers to "upstream" or "downstream" in the forward feed (feeding the workpiece forward) unless otherwise specified.

[0059] Further, a second guide piece 446 is provided facing leftward below the first guide piece 445 and comes into sliding contact from above with the upper right belt 42, which is transported downstream of the feed roller 442. The second guide piece 446 is disposed in the lowest position at the rear of the right belt guide 44, and when passing under the second guide piece 446, the upper right belt 42 comes into contact with the sewing material on the needle plate 101 to feed it.

[0060] As described above, the left and right belt guides 43, 44 have symmetrical shapes, and therefore, on the right side surface (the surface facing the presser foot 71) of the left belt guide 43, there are also provided a first guide piece (not shown) that slides from above against the upper left belt 41 transported upstream of the feed roller 432, and a second guide piece (not shown) that slides from above against the upper left belt 41 transported downstream of the feed roller 432, which are erected toward the right.

[0061] Furthermore, as shown in FIG. 10, a guide protrusion 713 is formed on the left side surface (the surface facing the belt guide 43) of the lower part of connecting portion 712 of presser foot 71, the guide protrusion 713 protruding cylindrically toward the left around the insertion hole of spindle 431, and a rolling element 714 is provided in front of the guide protrusion 713 and supported rotatably around an axis extending in the left-right direction. The lower portion of the outer circumferential surface of the guide protrusion 713 comes into sliding contact from above with the upper-left belt 41 that is transported upstream of the feed roller 432 and the first guide piece. Further, the lower portion of the outer circumferential surface of the rolling element 714 comes into contact from above with the upper-left belt 41 which is transported downstream of the feed roller 432 and the second guide piece.

[0062] Further, the lower portion of the connecting portion 712 of the presser foot 71 has a shape that is symmetrical with respect to a plane along the front-rear and top-bottom directions. Therefore, a cylindrical guide protrusion (not shown) that protrudes to the right around the insertion hole of the support shaft 431 is formed on the right side surface (the surface facing the belt guide 44) of the lower part of the connecting portion 712 of the presser foot 71, and a rolling body (not shown) that is supported rotatably around an axis extending in the left-right direction is provided in front of the guide protrusion. The lower portion of the outer circumferential surface of this guide protrusion comes into sliding contact from above with the upper right belt 42 which is transported upstream of the feed roller 442 and the first guide piece 445 . In addition, the lower portion of the outer circumferential surface of the rolling element abuts from above against the upper right belt 42 which is transported downstream of the feed roller 442 and the second guide piece 446 .

[0063] Note that, instead of the guide protrusions provided on the left and right side surfaces of the lower part of the connecting part 712, a configuration may be provided with rollers that rotate around an axis along the left and right direction around the support shaft 431. In other words, it is only necessary to provide a structure that can guide the left and right upper belts 41, 42 to pass below the support shaft 431 on the upstream side of the feed rollers 432, 442, respectively. Therefore, a structure like the guide pieces 445, 446 described above may also be used.

[0064] Also, the guide protrusion 713 may be provided so as to protrude rightward from the right side surface of the belt guide 43. The same applies to the belt guide 44. Moreover, the rolling element 714 may also be rotatably provided on the right side surface of the belt guide 43. The same applies to the belt guide 44.

[0065] 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.

[0066] As described above, each belt guide 43, 44 is pivotally supported by the support shaft 431 at the lower part of the connecting part 712 of the presser foot 71. One end of the tension spring 433, 443 is connected to the shaft parts 434, 444 provided at the front end of each belt guide 43, 44. The other end of each tension spring 433, 443 is connected to shaft members 75, 76 attached to the left and right side parts of the mounting base 74, respectively, and applies upward tension to the front end of each belt guide 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.

[0067] 11 is a perspective view of the shaft members 75, 76. The shaft members 75, 76 have plate-like main body portions 751, 761 that are long in a predetermined direction, locking shafts 752, 762 for the tension springs 433, 443 that are provided vertically on one flat surface of the main body portions 751, 761, and mounting shafts 753, 763 for the mounting base 74 that are provided vertically on the other flat surface of the main body portions 751, 761.

[0068] The main body portions 751, 761 are elliptical, and a locking shaft 752, 762 is provided on one flat surface at one end in the longitudinal direction of the main body portions 751, 761. Furthermore, a mounting shaft 753, 763 is provided on the other flat surface at the other end in the longitudinal direction of the main body portions 751, 761. With this structure, the locking shafts 752, 762 and the mounting shafts 753, 763 protrude in opposite directions across the main body portions 751, 761, are parallel to each other, and their centerlines are offset in the longitudinal direction of the main body portions 751, 761.

[0069] On the other hand, mounting holes (not shown) drilled along the left-right direction are formed in the rear ends of the left and right side surfaces of the mounting base 74, and groove-shaped mating recesses 741 are formed along the rear diagonally upward direction around the mounting holes on the left and right side surfaces of the mounting base 74. The shaft members 75, 76 can be attached to the rear end portions of the left and right sides of the mounting base 74 in two different ways.

[0070] 12 and 13 show a state in which the mounting shaft 753 of the shaft member 75 is inserted into the mounting hole at the rear end of the left side surface of the mounting base 74 and the main body portion 751 is fitted into the fitting recess 741. Figure 12 shows the state in which the main body 751 is fitted into the fitting recess 741 with the locking shaft 752 facing upward relative to the mounting shaft 753 of the shaft member 75, and Figure 13 shows the state in which the main body 751 is fitted into the fitting recess 741 with the locking shaft 752 facing downward relative to the mounting shaft 753.

[0071] In FIG. 12, it can be seen that the axial distance between shaft portion 434, to which both ends of tension spring 433 (not shown) are connected, and locking shaft 752 is longer, whereas in FIG. 13, the axial distance between shaft portion 434 and locking shaft 752 is shorter. In this way, the shaft members 75, 76 and the mounting base 74 can be attached so that the lengths of the left and right tension springs 433, 443 can be changed in two stages, and the tension of the tension springs 433, 443 can be adjusted.

[0072] In addition, on the surfaces of the main bodies 751, 761 of the shaft members 75, 76 facing the locking shafts 752, 762, operation grooves 751a, 761a are formed into which the tip of a tool such as a screwdriver is inserted to rotate the shaft members 75, 76 around the mounting shafts 753, 763. In addition, a screw hole is formed on the front or top side of the mounting base 74, penetrating to the left and right mounting holes, and a set screw such as a hexagonal socket set screw is screwed in to prevent the mounting shafts 753, 763 from accidentally falling off.

[0073] The left and right upper motors 45, 46 are motors whose rotation speed can be controlled, such as DC motors, AC motors, stepping motors, etc. Each of the motors 45, 46 may be provided with an encoder. As shown in FIG. 2, 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] [Evacuation mechanism] The reference numeral 60 shown in Figures 8 to 10 denotes a retraction mechanism for maintaining the right-side belt guide 44 in a retracted position when using a positioning ruler (not shown) for edge sewing, in which the needle drops while maintaining a constant width (edge ​​width) from the side edge (e.g., the right edge) of the workpiece. The positioning ruler has a stop plate that stops the right end of the sewing material against the left side surface during sewing. The positioning ruler supports the stop plate, which is located to the right of the needle drop position at a position that corresponds to a preset edge width relative to the needle drop position, so that the stop plate can be switched between a non-use position in which the stop plate is retracted upward and a use position in the vicinity of the needle plate.

[0082] When the adjusted edge width is small, the abutment plate is positioned close to the needle drop position. In this case, the rear end of the right belt guide 44 may interfere with the abutment plate, so the belt guide 44 is rotated around the support shaft 431 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.

[0083] 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 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. 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 rearward so as not to interfere with the belt guide 44.

[0084] [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.

[0085] Next, the behavior of the left and right belt guides 43, 44 when forward feeding (feeding the sewing material forward) and reverse feeding (feeding the sewing material backward) are performed by the upper feed mechanism 40 will be explained with reference to Figures 9, 10 and 14.

[0086] 14 is a left side view of the belt guide 43 and its surroundings in a comparative example in which the upper belt conveying path characteristic of the sewing machine 100 of this embodiment is not configured. The configuration of this comparative example does not include the guide protrusion 713 and the rolling element 714. Therefore, a conveying path is configured in which the left and right upper belts 41, 42 conveyed upstream of the feed rollers 432, 442 and the first guide piece pass above the shaft portion of the support shaft 431. During forward feeding, the left and right upper belts 41, 42 are transported along a transport path that descends obliquely downward and rearward from the left and right upper motors 45, 46 to the left and right belt guides 43, 44. When the rotation direction of the left and right upper motors 45, 46 is switched from forward feed to reverse feed, the left and right upper belts 41, 42 may become lifted up due to a force that pulls the rear ends of the left and right belt guides 43, 44 upward through the feed rollers 432, 442, the first guide piece and the second guide piece. As a result, the left and right belt guides 43, 44 may not be able to properly reverse the sewing workpiece, and the sewing workpiece may not be fed at the target value, resulting in poor feeding and / or fabric slippage.

[0087] In contrast, in the sewing machine 100 of this embodiment, as shown in Figures 9 and 10, in the forward feed direction, the left and right upper belts 41, 42 descend diagonally downward and rearward from the left and right upper motors 45, 46 via the guide mechanism 47, pass under the guide protrusion 713 (the shaft portion of the support shaft 431), pass under the first guide piece 445, go around from top to bottom around the rear portions of the left and right feed rollers 432, 442, pass under the second guide piece 446, pass under the rolling body 714, head diagonally upward and forward via the guide mechanism 47, and are transported along a transport path that returns to the left and right upper motors 45, 46. In this case, the left and right upper belts 41, 42 pass under the support shaft 431. Therefore, even if the rotation direction of the left and right upper motors 45, 46 is switched from forward feed to reverse feed, the force that the feed rollers 432, 442, the first guide piece and the second guide piece receive from the left and right upper belts 41, 42 acts in a direction centered on the support shaft 431 such that the rear ends of the left and right belt guides 43, 44 move downward. Therefore, the left and right upper belts 41, 42 are pressed against the workpiece at the rear ends of the left and right belt guides 43, 44, so that the feeding operation can be stably performed at the target feed amount even in the case of reverse feeding. In addition, even when switching from reverse feed to forward feed, the left and right upper belts 41, 42 are pressed against the workpiece at the rear ends of the left and right belt guides 43, 44, making it possible to perform stable feed operation at the target feed amount.

[0088] [Technical Effects of the Invention Embodiments] In the sewing machine 100, the conveying paths of the left and right upper belts 41, 42 are formed so that the left and right belt guides 43, 44 pass below the support shafts 431 of the belt guides 43, 44 upstream of the feed rollers 432, 442 in the conveying direction. Therefore, when the upper feed mechanism 40 is switched from forward feed to reverse feed, the rotational force acting on each belt guide 43, 44 due to the tension of the left and right upper belts 41, 42 is in a direction that rotates the rear end portions of the belt guides 43, 44 downward around the support shaft 431. This makes it possible to suppress the rear end portions of the belt guides 43, 44 that perform feeding from floating up from the sewing workpiece, and to perform stable feeding at the target feed amount. Therefore, it is possible to provide a sewing machine that maintains high sewing quality and is highly reliable.

[0089] The sewing machine 100 also includes tension springs 433, 443 that press the rear end sides of the belt guides 43, 44 against the needle plate 101. This makes it possible to stably prevent the rear end portions of the belt guides 43, 44 from lifting up from the workpiece regardless of whether the belt guides are in forward feed or reverse feed. Furthermore, it is possible to suppress the influence on the behavior of the rear end portions of the belt guides 43, 44 when switching between forward feed and reverse feed. Therefore, it is possible to provide a sewing machine that maintains high sewing quality and is highly reliable.

[0090] In addition, in the sewing machine 100, the shaft members 75, 76 which are the connecting portions of the tension springs 433, 443 on the presser foot 71 side have a function of adjusting the tension of the tension springs 433, 443. Therefore, the pressure of the left and right belt guides 43, 44 against the workpiece can be adjusted to be increased or decreased as required, making it possible to feed the workpiece appropriately according to the workpiece.

[0091] [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.

[0092] For example, although an example has been shown in which the belt guides 43, 44 of the upper feed mechanism 40 are supported by the presser foot 71, the present invention is not limited to this example. Other members that support the belt guides 43, 44 while maintaining them at a constant height from the needle plate 101 may be used. In addition, although the feed rollers 432, 442 are shown as an example of the guide portion, this is not limited to this, and a structure that guides the left and right upper belts 41, 42 by sliding them along the outer circumferential surface without rolling, such as a guide protrusion 713, may also be used.

[0093] In addition, in the above embodiment, a lockstitch sewing machine is exemplified as the sewing machine, but the configuration in which the belt is separated into a conveyor belt and a power transmission belt may also be applied to sewing machines of types other than a lockstitch sewing machine that employs a belt-based feed mechanism.

[0094] 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. 15, the needle hole 13 may be formed directly through the needle plate 101 and fixedly provided without moving up and down. [Explanation of symbols]

[0095] 11 Sewing Needle 12 Needle bar 13 Needle hole 20 Lower feed mechanism 21 Rear left lower belt (conveyor belt) 22 Front left lower belt (conveyor belt) 23 Front right lower belt (conveyor belt) 24 Rear right lower belt (conveyor belt) 25 First Motor 26 Second Motor 40 Upper feed mechanism (feed device) 41 Upper left belt (conveyor belt) 42 Upper right belt (conveyor belt) 43,44 Belt guide 431 Support shaft 432,442 Feed roller 433,443 Tension spring 434,444 Shaft 45 Upper left motor 46 Top Right Motor 47 Guide mechanism 70 Pressing mechanism 71 Presser foot (supporting member) 711 Bottom plate 712 Connection part 72 Pressing rod 74 Mounting stand 741 Fitting recess 75,76 Shaft member 100 Sewing Machine 101 Needle plate

Claims

1. A sewing machine including a feed device that feeds a workpiece by a conveyor belt that contacts the workpiece, a belt guide supported by a support member above the needle plate so as to be swingable about a support shaft extending in a direction perpendicular to the feed direction; a guide portion provided at a rear end portion of the belt guide and configured to turn the conveyor belt so that the conveying direction is the front side at the bottom portion of the belt guide; Equipped with a conveying path of the conveyor belt is formed so as to pass below the support shaft of the belt guide, upstream of the guide portion in a conveying direction.

2. 2. The sewing machine according to claim 1, wherein the guide portion is a rollable feed roller.

3. 2. The sewing machine according to claim 1, further comprising a spring for pressing a rear end side of the belt guide against the needle plate.

4. The spring is a tension spring, one end of which is connected to the belt guide and the other end of which is connected to the support member.

4. The sewing machine according to claim 3, wherein a connecting portion on the other end side of the tension spring has a function of adjusting the tension of the tension spring.

Images