Sewing machine

Abstract

To suppress complication of a sewing machine structure.SOLUTION: A sewing machine comprises: a sewing machine motor; an adjustment motor; a thread cutter having a fixed knife and a movable knife; a feed dog to feed a fabric forward or backward; a vertical feeding mechanism to vertically reciprocate the feed dog based on rotating force generated by the sewing machine motor; a horizontal feeding mechanism to reciprocate the feed dog in front-back direction based on the rotating force generated by the sewing machine motor; a thread cutting mechanism to move the movable knife based on the rotating force generated by the adjustment motor; and a feed amount adjusting mechanism to change feed amount and feed direction of the feed dog based on the rotating force generated by the adjustment motor.SELECTED DRAWING: Figure 19

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a sewing machine. [Background technology]

[0002] BACKGROUND ART In the technical field of sewing machines, a sewing machine such as that disclosed in Patent Document 1 is known. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Chinese Patent Application Publication No. 111501222 Summary of the Invention [Problem to be solved by the invention]

[0004] In a sewing machine having a thread cutting function, a feed amount adjustment function, and a backstitch function, there is a demand for a technology that can prevent the structure of the sewing machine from becoming complicated. For example, if the thread cutting function and the backstitch function are realized by two actuators and the feed amount adjustment function is realized manually, the structure of the sewing machine may become complicated.

[0005] The technology disclosed in this specification aims to prevent the structure of a sewing machine from becoming too complicated. [Means for solving the problem]

[0006] This specification discloses a sewing machine that includes a sewing machine motor, an adjustment motor, a thread cutter having a fixed knife and a moving knife, a feed dog that feeds fabric forward or backward, a vertical feed mechanism that moves the feed dog up and down reciprocally based on torque generated by the sewing machine motor, a horizontal feed mechanism that moves the feed dog back and forth based on torque generated by the sewing machine motor, a thread cutter mechanism that moves the moving knife based on torque generated by the adjustment motor, and a feed amount adjustment mechanism that changes the feed amount and feed direction of the feed dog based on torque generated by the adjustment motor. [Effects of the Invention]

[0007] According to the technology disclosed in this specification, the complexity of the sewing machine structure is suppressed. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a rear view of a sewing machine according to an embodiment. [Figure 2] FIG. 2 is a view of the inside of the sewing machine frame according to the embodiment, seen from the upper left rear. [Figure 3] FIG. 3 is a view of the interior of the bed according to the embodiment, seen from the upper left rear. [Figure 4] FIG. 4 is a view of the interior of the bed according to the embodiment, seen from the upper right front. [Figure 5] FIG. 5 is a view of the interior of the bed according to the embodiment as seen from the rear. [Figure 6] FIG. 6 is a view of the inside of the bed according to the embodiment as seen from above. [Figure 7] FIG. 7 is a view of the inside of the bed according to the embodiment as seen from below. [Figure 8] FIG. 8 is a block diagram showing a sewing machine according to an embodiment. [Figure 9] FIG. 9 is a view of the thread cutter according to the embodiment as seen from the upper left rear. [Figure 10] FIG. 10 is a view of the thread cutter according to the embodiment as seen from above. [Figure 11] FIG. 11 is a view of the thread cutting mechanism according to the embodiment as seen from the upper left rear. [Figure 12] FIG. 12 is a view of the thread cutting mechanism according to the embodiment as seen from the front right upper corner. [Figure 13] FIG. 13 is a view of the thread cutting mechanism according to the embodiment as seen from above. [Figure 14] FIG. 14 is a view of the thread cutting mechanism according to the embodiment as seen from below. [Figure 15] FIG. 15 is a view of the fabric feeding mechanism according to the embodiment as seen from the upper left rear. [Figure 16] FIG. 16 is a view of the fabric feeding mechanism according to the embodiment as seen from the front right upper corner. [Figure 17] FIG. 17 is a view of the fabric feeding mechanism according to the embodiment as viewed from the right. [Figure 18] FIG. 18 is a view of the fabric feeding mechanism according to the embodiment as seen from the left. [Figure 19] FIG. 19 is a view of a part of the thread cutting mechanism and a part of the feed amount adjusting mechanism according to the embodiment, as viewed from the front right above. [Figure 20] FIG. 20 is a view of a part of the thread cutting mechanism and a part of the feed amount adjusting mechanism according to the embodiment, as viewed from the front right above. [Figure 21] FIG. 21 is a view of a part of the thread cutting mechanism and a part of the feed amount adjusting mechanism according to the embodiment, as viewed from the lower right front. [Figure 22] FIG. 22 is an exploded perspective view showing a part of the thread cutting mechanism and a part of the feed amount adjusting mechanism according to the embodiment. [Figure 23] FIG. 23 is a timing chart for explaining the operations of the thread cutting mechanism and the feed amount adjusting mechanism according to the embodiment. [Figure 24] FIG. 24 is a timing chart for explaining the operations of the thread cutting mechanism and the feed amount adjusting mechanism according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the drawings. In the embodiments, an XYZ Cartesian coordinate system is set, and the positional relationship of each part will be described with reference to this XYZ Cartesian coordinate system. The direction parallel to the X axis in a predetermined plane is defined as the X-axis direction. The direction parallel to the Y axis in a predetermined plane that is perpendicular to the X axis is defined as the Y-axis direction. The direction parallel to the Z axis that is perpendicular to the predetermined plane is defined as the Z-axis direction. The direction of rotation or tilt around the X axis is defined as the θX direction. The direction of rotation or tilt around the Y axis is defined as the θY direction. The direction of rotation or tilt around the Z axis is defined as the θZ direction.

[0010] In this embodiment, the predetermined plane is parallel to the horizontal plane. The X-axis direction is the front-to-back direction. The Y-axis direction is the left-to-right direction. The Z-axis direction is the up-to-down direction. The +X direction is the forward direction, and the -X direction is the backward direction. The +Y direction is the left direction, and the -Y direction is the right direction. The +Z direction is the upward direction, and the -Z direction is the downward direction. The horizontal direction includes the front-to-back direction and the left-to-right direction.

[0011] [Sewing machine overview] 1 is a rear view of a sewing machine 1 according to an embodiment. In the embodiment, the sewing machine 1 is an industrial sewing machine. The sewing machine 1 is a twin-needle lockstitch sewing machine. As shown in FIG. 1, the sewing machine 1 has a sewing machine frame 2.

[0012] The sewing machine frame 2 has an arm 2A, a bed 2B, a base 2C, and a head 2D. The arm 2A is long in the left-right direction. The bed 2B is located below the arm 2A. The bed 2B is also long in the left-right direction. The bed 2B faces the arm 2A. The base 2C connects the right end of the arm 2A to the bed 2B. The base 2C is long in the up-down direction. The head 2D is provided at the left end of the arm 2A. The head 2D protrudes downward from the left end of the arm 2A.

[0013] FIG. 2 is a view of the inside of the sewing machine frame 2 according to the embodiment, seen from the upper left rear. FIG. 3 is a view of the inside of the bed 2B according to the embodiment, seen from the upper left rear. FIG. 4 is a view of the inside of the bed 2B according to the embodiment, seen from the upper right front. FIG. 5 is a view of the inside of the bed 2B according to the embodiment, seen from the rear. FIG. 6 is a view of the inside of the bed 2B according to the embodiment, seen from above. FIG. 7 is a view of the inside of the bed 2B according to the embodiment, seen from below. FIG. 8 is a block diagram showing the sewing machine 1 according to the embodiment.

[0014] As shown in Figures 1 to 8, the sewing machine 1 includes a needle bar 4, a feed dog 5, a thread cutter 6, a support member 7, a sewing machine motor 8, an adjustment motor 9, a needle bar drive mechanism 10, a fabric feed mechanism 11, a belt mechanism 12, a thread cutter mechanism 13, a controller 14, a pedal 15, and an operation panel 16.

[0015] The needle bar 4 holds the sewing needle 3. Two needle bars 4 are provided. The two needle bars 4 are arranged with a gap between them in the left-right direction. The needle bar 4 holds the sewing needle 3 so that the sewing needle 3 is parallel to the Z-axis. The needle bar 4 moves back and forth in the vertical direction. The needle bar 4 is supported by the head 2D. The sewing needle 3 has a threading hole through which the upper thread passes. The sewing needle 3 holds the upper thread on the inner surface of the threading hole. As the needle bar 4 moves back and forth in the vertical direction, the sewing needle 3 moves back and forth in the vertical direction while holding the upper thread. A needle plate (not shown) is located directly below the needle bar 4. The needle plate supports the fabric from below.

[0016] The feed dog 5 operates to feed the fabric supported by the needle plate forward or backward. The feed dog 5 is located below the needle bar 4. The feed dog 5 faces the needle bar 4. The feed dog 5 has two tooth portions spaced apart in the left-right direction. The feed dog 5 moves along a predetermined feed path to feed the fabric forward or backward. The feed dog 5 is located below the needle plate. The feed dog 5 moves along the feed path to appear and disappear through an opening provided in the needle plate. When feeding the fabric, at least a portion of the feed dog 5 protrudes upward from the top surface of the needle plate through the opening provided in the needle plate. A shuttle (not shown) is located below the feed dog 5. The shuttle supplies the bobbin thread to the fabric. The shuttle entangles the upper thread with the bobbin thread.

[0017] The thread cutter 6 cuts the upper thread and the lower thread. The thread cutter 6 is positioned below the feed dog 5. The thread cutter 6 has a fixed knife 17 and a moving knife 18. There are two thread cutters 6. The two thread cutters 6 are positioned with a gap between them in the left-right direction. When the upper thread and the lower thread are hooked on the moving knife 18, the moving knife 18 approaches the fixed knife 17, thereby cutting the upper thread and the lower thread.

[0018] The support member 7 supports the thread cutter 6. Two support members 7 are arranged in the left-right direction to correspond to the two thread cutters 6. The fixed knife 17 is fixed to the support member 7. The movable knife 18 is supported on the support member 7 so as to be movable.

[0019] The sewing machine motor 8 generates a rotational force for operating the needle bar 4, the feed dog 5, and the shuttle. The sewing machine motor 8 includes a servo motor. The sewing machine motor 8 is supported on the right side of the arm 2A.

[0020] The adjustment motor 9 generates a rotational force for changing the feed amount and feed direction of the feed dog 5. The adjustment motor 9 generates a rotational force for operating the thread cutter 6. The adjustment motor 9 includes a pulse motor. The adjustment motor 9 is disposed on the bed 2B. The adjustment motor 9 is fixed to at least a part of the bed 2B via a motor base 90.

[0021] The feed dog 5 moves along a predetermined feed orbit. The feed orbit is circular. The feed orbit is elliptical, circular, rectangular, or triangular. The feed amount of the feed dog 5 refers to the amplitude in the front-to-back direction of the feed dog 5 as it moves along the feed orbit. The feed direction of the feed dog 5 refers to the rotation direction of the feed dog 5 as it moves along the feed orbit. The feed direction of the feed dog 5 includes forward feed, which feeds the fabric forward, and reverse feed, which feeds the fabric backward. A straight stitch (normal stitch) is performed by the sewing machine needle 3 moving back and forth in the up and down direction while the fabric is fed forward. A backstitch is performed by the sewing machine needle 3 moving back and forth in the up and down direction while the fabric is fed backward.

[0022] The needle bar drive mechanism 10 reciprocates the needle bar 4 in the up and down direction based on the rotational force generated by the sewing machine motor 8. The needle bar drive mechanism 10 has an upper shaft 19 and a conversion mechanism 20.

[0023] The upper shaft 19 is connected to the sewing machine motor 8 via a coupling. The upper shaft 19 is long in the left-right direction. The upper shaft 19 rotates due to the rotational force generated by the sewing machine motor 8. The upper shaft 19 rotates in the θY direction around the central axis of the upper shaft 19.

[0024] The conversion mechanism 20 converts the rotation of the upper shaft 19 into reciprocating movement in the up and down direction. The conversion mechanism 20 is provided at the left end of the upper shaft 19. The upper end of the needle bar 4 is connected to the conversion mechanism 20. The rotational force of the upper shaft 19 is transmitted to the conversion mechanism 20. The conversion mechanism 20 reciprocates the needle bar 4 in the up and down direction based on the rotational force of the upper shaft 19.

[0025] Although not shown, the sewing machine 1 is equipped with a shuttle drive mechanism that rotates the shuttle based on the rotational force generated by the sewing machine motor 8. The shuttle rotates in synchronization with the up-and-down reciprocating movement of the needle bar 4 so that the bobbin thread is supplied to the fabric. The sewing machine 1 sews the fabric through cooperation between the shuttle and the sewing needle 3 held by the needle bar 4.

[0026] The fabric feeding mechanism 11 operates the feed dog 5 based on the rotational force generated by the sewing machine motor 8. The fabric feeding mechanism 11 moves the feed dog 5 in the front-to-back and up-to-down directions in synchronization with the up-to-down reciprocating movement of the needle bar 4 so that the fabric is fed forward or backward by the feed dog 5. The fabric feeding mechanism 11 moves the feed dog 5 according to a predetermined feed trajectory.

[0027] The fabric feed mechanism 11 has a vertical feed mechanism 22, a horizontal feed mechanism 24, and a feed amount adjustment mechanism 25. The vertical feed mechanism 22 reciprocates the feed dog 5 in the vertical direction based on the rotational force generated by the sewing machine motor 8. The vertical feed mechanism 22 includes a vertical feed shaft 21. The horizontal feed mechanism 24 reciprocates the feed dog 5 in the front-to-rear direction based on the rotational force generated by the sewing machine motor 8. The horizontal feed mechanism 24 includes a horizontal feed shaft 23. The feed amount adjustment mechanism 25 changes the feed amount and feed direction of the feed dog 5 based on the rotational force generated by the adjustment motor 9. The feed amount adjustment mechanism 25 includes a horizontal feed connecting rod 26. When the feed dog 5 moves based on the rotational force generated by the sewing machine motor 8, the feed amount of the feed dog 5 is changed, thereby changing the feed trajectory of the feed dog 5.

[0028] The vertical feed shaft 21 is long in the left-right direction. The vertical feed shaft 21 rotates in the θY direction around the central axis of the vertical feed shaft 21. The horizontal feed shaft 23 is long in the left-right direction. The horizontal feed shaft 23 is arranged rearward of the vertical feed shaft 21. The vertical feed shaft 21 and the horizontal feed shaft 23 are arranged parallel to each other. The horizontal feed shaft 23 rotates in the θY direction around the central axis of the horizontal feed shaft 23.

[0029] The feed amount adjustment mechanism 25 is disposed between the vertical feed shaft 21 and the horizontal feed shaft 23. The feed amount adjustment mechanism 25 is connected to each of the vertical feed shaft 21 and the horizontal feed shaft 23. The horizontal feed connecting rod 26 is connected to the vertical feed shaft 21. The vertical feed shaft 21 and the horizontal feed shaft 23 are connected via the feed amount adjustment mechanism 25.

[0030] The belt mechanism 12 transmits the rotational force generated by the sewing machine motor 8 to the fabric feed mechanism 11. The belt mechanism 12 transmits the rotational force generated by the sewing machine motor 8 to the vertical feed shaft 21. The vertical feed shaft 21 rotates based on the rotational force of the sewing machine motor 8 transmitted via the belt mechanism 12. The belt mechanism 12 has an upper pulley 27 fixed to the right end of the upper shaft 19, a lower pulley 28 fixed to the right end of the vertical feed shaft 21, and a timing belt 29 wound around the upper pulley 27 and the lower pulley 28.

[0031] When the upper shaft 19 rotates due to the rotational force generated by the sewing machine motor 8, the upper pulley 27 rotates together with the upper shaft 19. The rotational force of the upper shaft 19 is transmitted to the vertical feed shaft 21 via the upper pulley 27, timing belt 29, and lower pulley 28. The vertical feed shaft 21 rotates due to the rotational force of the upper shaft 19. The vertical feed shaft 21 rotates fully in the θY direction at the same rotational speed as the upper shaft 19.

[0032] The horizontal feed shaft 23 is connected to the vertical feed shaft 21 via a feed amount adjustment mechanism 25. The rotational force of the vertical feed shaft 21 is transmitted to the horizontal feed shaft 23 via the feed amount adjustment mechanism 25. The horizontal feed shaft 23 rotates based on the rotational force of the vertical feed shaft 21. When the vertical feed shaft 21 rotates fully in the θY direction, the horizontal feed connecting rod 26 moves back and forth in the front-to-rear direction. The horizontal feed shaft 23 rotates back and forth in the θY direction due to the reciprocating movement of the horizontal feed connecting rod 26.

[0033] The thread cutting mechanism 13 operates the thread cutter 6 based on the rotational force generated by the adjustment motor 9. Operating the thread cutter 6 includes moving the moving knife 18. The thread cutting mechanism 13 moves the moving knife 18 based on the rotational force generated by the adjustment motor 9.

[0034] The controller 14 controls each of the sewing machine motor 8 and the adjustment motor 9. The controller 14 has a processor such as a CPU (Central Processing Unit), a memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory), and an input / output interface including an input / output circuit that can input and output signals and data.

[0035] Pedal 15 is operated by an operator of the sewing machine 1. The operator operates pedal 15 with his foot. An operation signal generated by operating pedal 15 is sent to controller 14. Sewing machine motor 8 is driven or stopped based on the operating state of pedal 15. When pedal 15 is operated so that the front part of pedal 15 moves downward, controller 14 drives sewing machine motor 8. When pedal 15 is operated so that the rear part of pedal 15 moves downward, controller 14 starts processing to stop sewing machine 1. The processing to stop sewing machine 1 includes controlling sewing machine motor 8 so that thread cutter 6 can cut the upper thread and bobbin thread, and controlling adjustment motor 9 so that thread cutter 6 operates.

[0036] The operation panel 16 includes a flat panel display and a touch panel. The operation panel 16 is operated by an operator of the sewing machine 1. The operation panel 16 is provided on at least a part of the sewing machine frame 2. The operator operates the operation panel 16 with his / her fingers. The operator can operate the operation panel 16 to select the feed amount and feed direction of the feed dog 5. An operation signal generated by operating the operation panel 16 is sent to the controller 14. By changing the feed amount of the feed dog 5, the feed trajectory of the feed dog 5 is changed. The controller 14 controls the adjustment motor 9 so that the feed dog 5 moves in accordance with the feed amount and feed direction selected by the operation panel 16.

[0037] [Thread trimming mechanism] Fig. 9 is a view of the thread cutter 6 according to the embodiment as seen from the upper left rear. Fig. 10 is a view of the thread cutter 6 according to the embodiment as seen from above. Fig. 11 is a view of the thread cutter mechanism 13 according to the embodiment as seen from the upper left rear. Fig. 12 is a view of the thread cutter mechanism 13 according to the embodiment as seen from the upper right front. Fig. 13 is a view of the thread cutter mechanism 13 according to the embodiment as seen from above. Fig. 14 is a view of the thread cutter mechanism 13 according to the embodiment as seen from below.

[0038] The thread cutting mechanism 13 moves the moving knife 18 in the forward and backward directions based on the rotational force generated by the adjustment motor 9. A hook portion 30 and a blade 31 are provided at the tip of the moving knife 18. After the moving knife 18 moves so that the blade 31 of the moving knife 18 is separated from the counter knife 17, the blade 31 of the moving knife 18 moves so that it approaches the counter knife 17, whereby the upper thread and the lower thread are hooked on the hook portion 30. With the upper thread and the lower thread hooked on the hook portion 30, the moving knife 18 moves so that the blade 31 of the moving knife 18 approaches the counter knife 17, whereby the upper thread and the lower thread are cut by the blade 31 of the moving knife 18 and the counter knife 17.

[0039] Two thread cutters 6 are arranged in the left-right direction. The thread cutters 6 are supported by support members 7. Two support members 7 are arranged in the left-right direction. The left-side thread cutter 6 is supported by the left-side support member 7. The right-side thread cutter 6 is supported by the right-side support member 7. In the following description, the support member 7 supporting the left-side thread cutter 6 will be referred to as support member 7L, and the support member 7 supporting the right-side thread cutter 6 will be referred to as support member 7R, as appropriate. The counter knife 17 of the left-side thread cutter 6 will be referred to as counter knife 17L, and the counter knife 17 of the right-side thread cutter 6 will be referred to as counter knife 17R, as appropriate. The moving knife 18 of the left-side thread cutter 6 will be referred to as moving knife 18L, and the moving knife 18 of the right-side thread cutter 6 will be referred to as moving knife 18R, as appropriate.

[0040] The support member 7L is disposed to the left and below the feed dog 5. The support member 7R is disposed to the right and below the feed dog 5. The feed dog 5 is disposed between the support members 7L and 7R in the left-right direction.

[0041] The fixed knife 17L is fixed to the support member 7L. The fixed knife 17R is fixed to the support member 7R. The movable knife 18L is supported by the support member 7L so as to be movable in the front-rear direction. The movable knife 18R is supported by the support member 7R so as to be movable in the front-rear direction.

[0042] When the moving knife 18L moves forward, the blade 31 of the moving knife 18L moves away from the counter knife 17L. When the moving knife 18L moves rearward, the blade 31 of the moving knife 18L moves closer to the counter knife 17L. After the moving knife 18L moves forward, the moving knife 18L moves rearward, causing the upper thread and lower thread on the left side to be hooked by the hook portion 30 of the moving knife 18L. When the moving knife 18L moves rearward with the upper thread and lower thread on the left side hooked by the hook portion 30 of the moving knife 18L, the upper thread and lower thread on the left side are cut by the blade 31 of the moving knife 18L and the counter knife 17L.

[0043] When the moving knife 18R moves rearward, the blade 31 of the moving knife 18R moves away from the counter knife 17R. When the moving knife 18R moves forward, the blade 31 of the moving knife 18R moves closer to the counter knife 17R. After the moving knife 18R moves rearward, the moving knife 18R moves forward, causing the right upper thread and bobbin thread to be hooked on the hook portion 30 of the moving knife 18R. When the moving knife 18R moves forward with the right upper thread and bobbin thread hooked on the hook portion 30 of the moving knife 18R, the right upper thread and bobbin thread are cut by the blade 31 of the moving knife 18R and the counter knife 17R.

[0044] A cam 32 is fixed to the output shaft 9A of the adjustment motor 9. The cam 32 has a cam groove 33. The cam 32 rotates as the output shaft 9A of the adjustment motor 9 rotates. In this embodiment, the output shaft 9A of the adjustment motor 9 protrudes rightward from the stator of the adjustment motor 9.

[0045] The thread cutting mechanism 13 is connected to the cam 32. The thread cutting mechanism 13 has a roller 45, a thread cutting arm 34, a drive link 35, a right rotating link 36, a synchronization link 37, a left rotating link 38, a right rod 39, a left rod 40, a right slide link 41, a left slide link 42, a right movable member 43, and a left movable member 44.

[0046] The roller 45 is disposed in the cam groove 33. The roller 45 moves along the cam groove 33. The thread cutting arm 34 is rotatably supported by the roller 45. The thread cutting arm 34 is connected to the cam 32 via the roller 45.

[0047] The base end of the thread cutting arm 34 is connected to a predetermined location on the bed 2B by a shoulder screw 46. The shoulder screw 46 rotatably supports the base end of the thread cutting arm 34. The shoulder screw 46 allows the base end of the thread cutting arm 34 to rotate about a rotation axis AX1 that passes through the shoulder screw 46. The rotation axis AX1 is parallel to the Z axis.

[0048] The drive link 35 is rotatably connected to the tip of the thread cutting arm 34. The base end of the drive link 35 is rotatably connected to the tip of the thread cutting arm 34 via a joint 47. The thread cutting arm 34 and the drive link 35 are relatively rotatable about a rotation axis AX2 that passes through the joint 47. The rotation axis AX2 is parallel to the Z axis.

[0049] 14, the drive link 35 includes a first drive link 35A connected to the tip of the thread cutting arm 34, and a second drive link 35B connected to the first drive link 35A. An elongated hole 35C is formed in the second drive link 35B. Two screws 35D are inserted into the elongated holes 35C to secure the first drive link 35A and the second drive link 35B together.

[0050] The right rotating link 36 is rotatably connected to the tip end of the drive link 35. The base end of the right rotating link 36 is rotatably connected to the tip end of the drive link 35 via a joint 48. The drive link 35 and the right rotating link 36 are relatively rotatable about a rotation axis AX3 that passes through the joint 48. The rotation axis AX3 is parallel to the Z axis.

[0051] A pivot 49 is provided at the center of the right rotation link 36. The right rotation link 36 rotates in the θZ direction around a rotation axis AX4 that passes through the pivot 49. The rotation axis AX4 is parallel to the Z axis.

[0052] The synchronous link 37 is rotatably connected to the tip end of the right rotating link 36. The base end of the synchronous link 37 is rotatably connected to the tip end of the right rotating link 36 via a joint 50. The right rotating link 36 and the synchronous link 37 are relatively rotatable about a rotation axis AX5 that passes through the joint 50. The rotation axis AX5 is parallel to the Z axis.

[0053] 14, the synchronous link 37 includes a first synchronous link 37A connected to the tip of the right-handed rotating link 36 and a second synchronous link 37B connected to the first synchronous link 37A. An elongated hole 37C is formed in the second synchronous link 37B. Two screws 37D are inserted into the elongated holes 37C to secure the first synchronous link 37A and the second synchronous link 37B together.

[0054] The left rotating link 38 is rotatably connected to the tip end of the synchronous link 37. The base end of the left rotating link 38 is rotatably connected to the tip end of the synchronous link 37 via a joint 51. The synchronous link 37 and the left rotating link 38 are relatively rotatable about a rotation axis AX6 that passes through the joint 51. The rotation axis AX6 is parallel to the Z axis.

[0055] A pivot 52 is provided at the center of the left rotating link 38. The left rotating link 38 rotates in the θZ direction around a rotation axis AX7 that passes through the pivot 52. The rotation axis AX7 is parallel to the Z axis.

[0056] The right rod 39 extends upward from the right rotating link 36. The lower end of the right rod 39 is fixed to the right rotating link 36. The central axis of the right rod 39 and the rotation axis AX4 of the right rotating link 36 coincide with each other. When the right rotating link 36 rotates, the right rod 39 rotates in the θZ direction.

[0057] The left rod 40 extends upward from the left rotating link 38. The lower end of the left rod 40 is fixed to the left rotating link 38. The central axis of the left rod 40 and the rotation axis AX7 of the left rotating link 38 coincide with each other. When the left rotating link 38 rotates, the left rod 40 rotates in the θZ direction.

[0058] The right slide link 41 is connected to the right pivot link 36 via the right rod 39. The base end of the right slide link 41 is fixed to the upper end of the right rod 39. As the right rod 39 rotates, the tip of the right slide link 41 pivots partially around the pivot axis AX4. A right slide pin 53 is provided at the tip of the right slide link 41. The right slide pin 53 protrudes downward from the tip of the lower surface of the right slide link 41.

[0059] The left slide link 42 is connected to the left pivot link 38 via the left rod 40. The base end of the left slide link 42 is fixed to the upper end of the left rod 40. As the left rod 40 rotates, the tip of the left slide link 42 pivots partially around the pivot axis AX7. A left slide pin 54 is provided at the tip of the left slide link 42. The left slide pin 54 protrudes downward from the tip of the lower surface of the left slide link 42.

[0060] The right movable member 43 is movably supported by the support member 7R. The right movable member 43 supports the moving knife 18R. The moving knife 18R is fixed to the right movable member 43. A slider portion 43A is provided at the bottom of the right movable member 43. A fixed portion 43B to which the moving knife 18R is fixed is provided at the top of the right movable member 43. The base end of the moving knife 18R is fixed to the fixed portion 43B of the right movable member 43 by a screw. A guide groove 55 is provided in the support member 7R. The slider portion 43A of the right movable member 43 is positioned in the guide groove 55. The guide groove 55 guides the slider portion 43A in the front-to-rear direction. The right movable member 43 has an elongated hole 56 into which the right slide pin 53 is inserted. The elongated hole 56 is provided in the slider portion 43A. The elongated hole 56 is long in the left-to-right direction.

[0061] The left movable member 44 is movably supported by the support member 7L. The left movable member 44 supports the moving knife 18L. The moving knife 18L is fixed to the left movable member 44. A slider portion 44A is provided at the bottom of the left movable member 44. A fixed portion 44B to which the moving knife 18L is fixed is provided at the top of the left movable member 44. The base end of the moving knife 18L is fixed to the fixed portion 44B of the left movable member 44 by a screw. A guide groove 57 is provided in the support member 7L. The slider portion 44A of the left movable member 44 is positioned in the guide groove 57. The guide groove 57 guides the slider portion 44A in the front-to-rear direction. The left movable member 44 has an elongated hole 58 into which the left slide pin 54 is inserted. The elongated hole 58 is provided in the slider portion 44A. The elongated hole 58 is long in the left-to-right direction.

[0062] The tip of the moving knife 18R is disposed rearward of the base end of the moving knife 18R. The tip of the moving knife 18R protrudes rearward from the fixed portion 43B of the right movable member 43. The tip of the moving knife 18R is provided with a hook portion 30 around which the upper thread and the lower thread are hooked, and a blade 31 that cuts the upper thread and the lower thread.

[0063] The tip of the moving knife 18L is disposed forward of the base end of the moving knife 18L. The tip of the moving knife 18L protrudes forward from the fixed portion 43B of the left movable member 44. The tip of the moving knife 18L is provided with a hook portion 30 around which the upper thread and the lower thread are hooked, and a blade 31 that cuts the upper thread and the lower thread.

[0064] The thread cutting mechanism 13 moves the moving knife 18 by rotation of the drive link 35. As shown by the solid arrow in Figure 13, when the output shaft 9A of the adjustment motor 9 rotates in the forward direction, the roller 45 moves along the cam groove 33. As the roller 45 moves, the thread cutting arm 34 rotates in the θZ direction about the shoulder screw 46 so that the tip of the thread cutting arm 34 moves to the right. The cam groove 33 is shaped so that the tip of the thread cutting arm 34 moves to the right when the output shaft 9A of the adjustment motor 9 rotates in the forward direction.

[0065] When the tip of the thread cutting arm 34 moves to the right, the right rotating link 36 connected to the thread cutting arm 34 via the drive link 35 rotates. The right rotating link 36 rotates such that the base end of the right rotating link 36 moves to the right and the tip of the right rotating link 36 moves to the left. When the right rotating link 36 rotates such that the tip of the right rotating link 36 moves to the left, the left rotating link 38 connected to the right rotating link 36 via the synchronization link 37 rotates. The left rotating link 38 rotates such that the base end of the left rotating link 38 moves to the left and the tip of the left rotating link 38 moves to the right.

[0066] When the right rotating link 36 rotates, the right slide link 41 connected to the right rotating link 36 via the right rod 39 rotates. The right slide link 41 rotates such that the tip of the right slide link 41 moves rearward. The right slide pin 53 of the right slide link 41 is inserted into the elongated hole 56 of the right movable member 43. When the tip of the right slide link 41 moves rearward, the moving knife 18R supported by the right movable member 43 moves rearward. After the moving knife 18R moves rearward, the moving knife 18R moves forward, whereby the right upper thread and bobbin thread are hooked on the hook portion 30 of the moving knife 18R.

[0067] When the left rotating link 38 rotates, the left slide link 42 connected to the left rotating link 38 via the left rod 40 rotates. The left slide link 42 rotates so that the tip of the left slide link 42 moves forward. The left slide pin 54 of the left slide link 42 is inserted into the elongated hole 58 of the left movable member 44. When the tip of the left slide link 42 moves forward, the moving knife 18L supported by the left movable member 44 moves forward. After the moving knife 18L moves forward, the moving knife 18L moves rearward, causing the upper thread and bobbin thread on the left side to be hooked on the hook portion 30 of the moving knife 18L.

[0068] As indicated by the dotted arrows in Figure 13, after the upper and lower threads are hooked on the hook portion 30 of the moving knife 18R and the upper and lower threads are hooked on the hook portion 30 of the moving knife 18L, when the output shaft 9A of the adjustment motor 9 rotates in the reverse direction, the thread cutting arm 34, the drive link 35, the right rotating link 36, the synchronized link 37, and the left rotating link 38 rotate so that the moving knife 18R moves forward and the moving knife 18L moves backward. With the upper and lower threads hooked on the hook portion 30 of the moving knife 18R, when the moving knife 18R moves forward so that the blade 31 of the moving knife 18R approaches the counter knife 17R, the upper and lower threads hooked on the hook portion 30 of the moving knife 18R are cut by the blade 31 of the moving knife 18R and the counter knife 17R. In addition, when the upper thread and lower thread are hooked on the hook portion 30 of the moving knife 18L and the moving knife 18L moves backward so that the blade 31 of the moving knife 18L approaches the fixed knife 17L, the upper thread and lower thread hooked on the hook portion 30 of the moving knife 18L are cut by the blade 31 of the moving knife 18L and the fixed knife 17L.

[0069] [Fabric feeding mechanism] Fig. 15 is a view of the fabric feeding mechanism 11 according to the embodiment as seen from the upper left rear. Fig. 16 is a view of the fabric feeding mechanism 11 according to the embodiment as seen from the upper right front. Fig. 17 is a view of the fabric feeding mechanism 11 according to the embodiment as seen from the right. Fig. 18 is a view of the fabric feeding mechanism 11 according to the embodiment as seen from the left.

[0070] The fabric feed mechanism 11 has a feed table 59 that holds the feed dog 5, a vertical feed mechanism 22 that moves the feed table 59 up and down reciprocally based on the rotational force generated by the sewing machine motor 8, a horizontal feed mechanism 24 that moves the feed table 59 back and forth based on the rotational force generated by the sewing machine motor 8, and a feed amount adjustment mechanism 25 that changes the feed amount and feed direction of the feed dog 5.

[0071] The feed base 59 includes a holding portion 59A that is long in the front-to-rear direction, and a connecting portion 59B that extends forward and downward from the lower portion of the holding portion 59A. The feed dog 5 is held by the holding portion 59A. As the feed base 59 moves back and forth in the up-and-down direction, the two feed dogs 5 move back and forth in the up-and-down direction. As the feed base 59 moves back and forth in the front-to-rear direction, the feed dogs 5 move back and forth in the front-to-rear direction.

[0072] The vertical feed mechanism 22 has a vertical feed shaft 21 that rotates based on the rotational force generated by the sewing machine motor 8, a vertical feed eccentric cam 60 fixed to the left end of the vertical feed shaft 21, and a vertical feed connecting rod 61 attached to the vertical feed eccentric cam 60. The vertical feed connecting rod 61 is connected to the feed table 59.

[0073] The vertical feed eccentric cam 60 is held at the base end of a vertical feed connecting rod 61. The vertical feed connecting rod 61 extends downward from the vertical feed eccentric cam 60. The tip of the vertical feed connecting rod 61 is connected to the lower end of the connecting portion 59B of the feed base 59. The tip of the vertical feed connecting rod 61 and the lower end of the connecting portion 59B are relatively rotatable in the θY direction. When the vertical feed shaft 21 rotates fully in the θY direction, the vertical feed eccentric cam 60 moves up and down with a stroke twice the eccentric amount of the vertical feed eccentric cam 60. The vertical reciprocating movement of the vertical feed eccentric cam 60 causes the vertical feed connecting rod 61 to move up and down. The vertical reciprocating movement of the vertical feed connecting rod 61 causes the feed base 59 connected to the vertical feed connecting rod 61 to move up and down. As the feed table 59 moves up and down, the feed dog 5 moves up and down.

[0074] The horizontal feed mechanism 24 has a horizontal feed shaft 23 connected to the vertical feed shaft 21 via a feed amount adjustment mechanism 25, and a horizontal feed arm 62 fixed to the left end of the horizontal feed shaft 23. The horizontal feed arm 62 is connected to the feed table 59.

[0075] The horizontal feed arm 62 extends upward from the horizontal feed shaft 23. The tip of the horizontal feed arm 62 is connected to the rear end of the holder 59A of the feed table 59. The tip of the horizontal feed arm 62 and the rear end of the holder 59A are rotatable relative to each other in the θY direction.

[0076] The feed amount adjustment mechanism 25 has a horizontal feed connecting rod 26 connected to the vertical feed shaft 21. The horizontal feed connecting rod 26 is long in the front-to-rear direction. A horizontal feed eccentric cam 63 is fixed to the vertical feed shaft 21. The front end of the horizontal feed connecting rod 26 is connected to the vertical feed shaft 21 via the horizontal feed eccentric cam 63. The front end of the horizontal feed connecting rod 26 rotatably holds the horizontal feed eccentric cam 63.

[0077] When the vertical feed shaft 21 rotates fully in the θY direction, the horizontal feed connecting rod 26 moves back and forth in the front-to-rear direction. When the vertical feed shaft 21 rotates fully in the θY direction, the rear end of the horizontal feed connecting rod 26 moves back and forth in the front-to-rear direction with a stroke twice the eccentricity of the horizontal feed eccentric cam 63. The reciprocating movement of the horizontal feed connecting rod 26 is transmitted to the horizontal feed shaft 23. The horizontal feed shaft 23 rotates back and forth in the θY direction due to the reciprocating movement of the horizontal feed connecting rod 26. As the horizontal feed shaft 23 rotates back and forth in the θY direction, the tip of the horizontal feed arm 62 moves back and forth in the front-to-rear direction. As the tip of the horizontal feed arm 62 moves back and forth in the front-to-rear direction, the feed table 59 connected to the horizontal feed arm 62 moves back and forth in the front-to-rear direction. As the feed table 59 moves back and forth in the front-to-rear direction, the feed dog 5 moves back and forth in the front-to-rear direction.

[0078] The feed amount adjustment mechanism 25 is connected to the cam 32. The feed amount adjustment mechanism 25 has a first link 65, an adjustment arm 66, a feed amount adjuster 67, the horizontal feed connecting rod 26, a second link 68, and a swing arm 69.

[0079] The first link 65 is attached to the right end surface of the cam 32. The first link 65 is connected to the right end surface of the cam 32 by a shoulder screw 70. The shoulder screw 70 rotatably supports the first link 65. The shoulder screw 70 is attached at a position offset from the central axis of the cam 32. When the adjustment motor 9 is driven, the cam 32 rotates in the θY direction around the central axis of the cam 32. When the cam 32 rotates, the first link 65 moves.

[0080] The adjustment arm 66 is connected to the first link 65. The adjustment arm 66 is rotatably connected to the first link 65 via a pin 71. When the cam 32 rotates, the first link 65 rotates, causing the adjustment arm 66 to rotate.

[0081] The feed amount adjustment body 67 is connected to the adjustment arm 66. The adjustment arm 66 is fixed to the left end of the feed amount adjustment body 67. The feed amount adjustment body 67 is connected to the first link 65 via the adjustment arm 66. When the adjustment arm 66 rotates, the feed amount adjustment body 67 rotates in synchronization with the adjustment arm 66.

[0082] The horizontal feed connecting rod 26 is connected to both the vertical feed shaft 21 and the feed amount adjustment body 67. The front end of the horizontal feed connecting rod 26 is connected to the vertical feed shaft 21 via the horizontal feed eccentric cam 63. The rear end of the horizontal feed connecting rod 26 is rotatably connected to the feed amount adjustment body 67. The horizontal feed connecting rod 26 reciprocates in the front-to-rear direction with every full rotation of the vertical feed shaft 21.

[0083] The second link 68 is connected to the feed amount adjuster 67. The front end of the second link 68 is connected to the feed amount adjuster 67 so as to be rotatable.

[0084] The swing arm 69 is connected to both the horizontal feed shaft 23 and the second link 68. The rear end of the second link 68 is rotatably connected to the front end of the swing arm 69. The rear end of the swing arm 69 is fixed to the horizontal feed shaft 23.

[0085] When the horizontal feed connecting rod 26 moves back and forth in the front-to-rear direction due to a full rotation of the vertical feed shaft 21, the rod portion 67A of the feed amount adjuster 67 and the second link 68 each move back and forth in the front-to-rear direction. When the second link 68 moves back and forth in the front-to-rear direction, the swing arm 69 swings. When the swing arm 69 swings, the horizontal feed shaft 23 rotates back and forth in the θY direction.

[0086] The feed amount adjustment mechanism 25 changes the feed amount and feed direction of the feed dog 5 by rotating the feed amount adjuster 67. When the adjustment motor 9 is driven and the output shaft 9A rotates, the cam 32 rotates. The rotation of the cam 32 rotates the first link 65 and the adjustment arm 66. The rotation of the adjustment arm 66 rotates the feed amount adjuster 67. The rotation of the feed amount adjuster 67 changes the relative angle between the feed amount adjuster 67 and the second link 68 in the θY direction. The change in the relative angle between the feed amount adjuster 67 and the second link 68 changes the feed amount and feed direction of the feed dog 5.

[0087] When the feed amount adjuster 67 is located at a neutral position in the rotation direction of the feed amount adjuster 67, the swing arm 69 does not swing even if the horizontal feed connecting rod 26 moves back and forth in the front-to-rear direction. Because the swing arm 69 does not swing, the horizontal feed shaft 23 does not rotate back and forth, and the feed amount of the feed dog 5 becomes zero.

[0088] When the feed amount adjuster 67 rotates from the neutral position, the swing arm 69 swings based on the reciprocating movement of the horizontal feed connecting rod 26. As the swing arm 69 swings, the horizontal feed shaft 23 rotates back and forth, and the feed dog 5 moves in the front-to-rear direction. The feed amount of the feed dog 5 is adjusted based on the rotation angle of the feed amount adjuster 67 from the neutral position. The greater the rotation angle of the feed amount adjuster 67 from the neutral position, the greater the feed amount of the feed dog 5.

[0089] When the feed amount adjuster 67 rotates in the forward direction from the neutral position, the feed dog 5 feeds the fabric forward. When the feed amount adjuster 67 rotates in the reverse direction from the neutral position, the feed dog 5 feeds the fabric backward. A straight stitch (normal stitch) is performed by the sewing machine needle 3 moving back and forth in the up and down direction while the fabric is fed forward. A back stitch is performed by the sewing machine needle 3 moving back and forth in the up and down direction while the fabric is fed backward.

[0090] When adjusting the feed amount and feed direction of the feed dog 5, the controller 14 controls the adjustment motor 9 so that the feed amount adjuster 67 rotates.

[0091] [Relationship between thread trimming mechanism and feed amount adjustment mechanism] Fig. 19 is a view of a portion of the thread cutting mechanism 13 and a portion of the feed amount adjustment mechanism 25 according to the embodiment, as viewed from the upper right front. Fig. 20 is a view of a portion of the thread cutting mechanism 13 and a portion of the feed amount adjustment mechanism 25 according to the embodiment, as viewed from the upper right front. Fig. 21 is a view of a portion of the thread cutting mechanism 13 and a portion of the feed amount adjustment mechanism 25 according to the embodiment, as viewed from the lower right front. Fig. 22 is an exploded perspective view showing a portion of the thread cutting mechanism 13 and a portion of the feed amount adjustment mechanism 25 according to the embodiment. Figs. 20, 21, and 22 each correspond to a view in which the drive link 35, the horizontal feed connecting rod 26, the second link 68, and the swing arm 69 are omitted from Fig. 19.

[0092] 19 to 22, the thread cutting mechanism 13 and the feed amount adjustment mechanism 25 are each connected to the output shaft 9A of the adjustment motor 9. A cam 32 is fixed to the output shaft 9A of the adjustment motor 9. The thread cutting mechanism 13 and the feed amount adjustment mechanism 25 are each connected to the output shaft 9A via the cam 32.

[0093] The thread cutting mechanism 13 has a roller 45 disposed in the cam groove 33 of the cam 32, a thread cutting arm 34 rotatably supported by the roller 45, and a drive link 35 rotatably connected to the tip of the thread cutting arm 34. The feed amount adjustment mechanism 25 has a first link 65 rotatably connected to the right end face of the cam 32, an adjustment arm 66 connected to the first link 65, and a feed amount adjuster 67 connected to the adjustment arm 66. The moving knife 18 moves as the drive link 35 rotates. The feed amount and feed direction of the feed dog 5 are changed by rotating the feed amount adjuster 67.

[0094] The horizontal feed connecting rod 26 and the second link 68 are each connected to a rod portion 67A provided on the feed amount adjuster 67. The rear end of the horizontal feed connecting rod 26 is rotatably connected to the rod portion 67A. The front end of the second link 68 is rotatably connected to the rod portion 67A.

[0095] The output shaft 9A of the adjustment motor 9 is inserted into a fixing hole 32A provided in the center of the cam 32. The central axis of the output shaft 9A and the rotation axis RX of the adjustment motor 9 coincide with each other. The central axis of the cam 32 and the rotation axis RX coincide with each other. The rotation axis RX is parallel to the Y axis.

[0096] The shoulder screw 70 is inserted into the insertion hole 32B of the cam 32 through the first hole 65A provided in the first link 65. The insertion hole 32B is provided at a position offset from the central axis of the cam 32.

[0097] The first link 65 and the adjustment arm 66 are connected via a pin 71. The pin 71 is inserted into the second hole 65B of the first link 65 and the insertion hole 66A of the adjustment arm 66.

[0098] The adjustment arm 66 and the feed amount adjustment body 67 are fixed together by two screws 72. The two screws 72 are inserted into two insertion holes 66B provided in the adjustment arm 66 and two screw holes provided at the left end of the feed amount adjustment body 67.

[0099] [Sewing machine operation] Fig. 23 is a timing chart for explaining the operations of the thread cutting mechanism 13 and the feed amount adjustment mechanism 25 according to the embodiment. Fig. 23 shows the relationship between the rotation angle of the output shaft 9A of the adjustment motor 9 and the thread cutting mechanism 13 and the feed amount adjustment mechanism 25. The thread cutting mechanism 13 and the feed amount adjustment mechanism 25 are each connected to the output shaft 9A of the adjustment motor 9 via a cam 32. One adjustment motor 9 cuts the upper thread and the bobbin thread, changes the feed amount of the feed dog 5, and changes the feed direction of the feed dog 5.

[0100] 23, the horizontal axis represents the rotation angle of the output shaft 9A of the adjustment motor 9. The output shaft 9A can rotate between an initial angle of 0° and a maximum angle of 360°. In the following description, the direction of rotation from 0° to 360° will be referred to as the forward direction, and the direction of rotation from 360° to 0° will be referred to as the reverse direction, as appropriate.

[0101] In Figure 23, the vertical axis indicates the feed amount and feed direction of the feed dog 5. A feed amount of zero means that the fabric is not fed, a positive feed amount means that the fabric is fed forward, and a negative feed amount means that the fabric is fed backward. The feed amount and feed direction of the feed dog 5 are determined by the rotation angle of the feed amount adjuster 67. There is a one-to-one correspondence between the rotation angle of the feed amount adjuster 67 and the feed amount and feed direction of the feed dog 5. The vertical axis may be considered to be the rotation angle of the feed amount adjuster 67. Line Lc indicates the relationship between the output shaft 9A and the feed amount and feed direction of the feed dog 5.

[0102] When the feed amount adjuster 67 is located at the neutral position in the rotation direction of the feed amount adjuster 67, the feed amount of the feed dog 5 becomes zero. When the feed amount adjuster 67 rotates in the forward direction from the neutral position, the feed dog 5 moves to feed the fabric forward. The feed dog 5 feeds the fabric forward. When the feed amount adjuster 67 rotates in the reverse direction from the neutral position, the feed dog 5 moves to feed the fabric backward. The feed dog 5 feeds the fabric backward.

[0103] In Figure 23, the vertical axis indicates the position of the moving knife 18. The position of the moving knife 18 is determined by the rotation angle of the cam 32. Line Lb indicates the relationship between the rotation angle of the output shaft 9A and the position of the moving knife 18. The initial position of the moving knife 18 is the position where the blade 31 of the moving knife 18 is closest to the counter knife 17. The most forward position of the moving knife 18 is the position where the blade 31 of the moving knife 18 is furthest from the counter knife 17. The initial position of the moving knife 18R is the front end position of the movable range of the moving knife 18R. The most forward position of the moving knife 18R is the rear end position of the movable range of the moving knife 18R. The initial position of the moving knife 18L is the rear end position of the movable range of the moving knife 18L. The most forward position of the moving knife 18L is the front end position of the movable range of the moving knife 18L.

[0104] 23, the feed amount adjuster 67 rotates to change the feed amount and feed direction of the feed dog 5 within a feed amount adjustment range RA (first rotation range) in which the rotation angle of the output shaft 9A of the adjustment motor 9 is greater than 0° and less than angle α1. Angle α1 is a value greater than 90° and less than 180°. In this embodiment, angle α1 is approximately 108°.

[0105] When the rotation angle of the output shaft 9A is the intermediate angle αm of the feed amount adjustment range RA, the feed amount adjuster 67 is located in the neutral position. When the rotation angle of the output shaft 9A reaches the intermediate angle αm and the feed amount adjuster 67 is located in the neutral position, the feed amount of the feed dog 5 becomes zero. The intermediate angle αm is approximately 54°.

[0106] When the rotation angle of the output shaft 9A is between 0° and the intermediate angle αm, the feed dog 5 moves to feed the fabric backward. That is, when the rotation angle of the output shaft 9A is between 0° and the intermediate angle αm, the fabric is fed backward. When the output shaft 9A rotates in the reverse direction from the intermediate angle αm, the feed amount of the fabric fed backward increases. When the rotation angle of the output shaft 9A becomes 0°, the feed amount of the backward feed reaches its maximum value.

[0107] When the rotation angle of the output shaft 9A is between the intermediate angle αm and the angle α1, the feed dog 5 moves to feed the fabric forward. That is, when the rotation angle of the output shaft 9A is between the intermediate angle αm and the angle α1, the fabric is fed forward. When the output shaft 9A rotates in the forward direction from the intermediate angle αm, the feed amount of the fabric fed forward increases. When the rotation angle of the output shaft 9A reaches the angle α1, the forward feed amount reaches its maximum value.

[0108] A straight stitch (normal stitch) is performed by the sewing machine needle 3 moving back and forth in the vertical direction while the fabric is fed forward. A backstitch is performed by the sewing machine needle 3 moving back and forth in the vertical direction while the fabric is fed backward. The feed trajectory of the feed dog 5 is changed by changing the feed amount of the feed dog 5. The operator can change the feed amount and feed direction of the feed dog 5 by operating the operation panel 16. Based on an operation signal generated by operating the operation panel 16, the controller 14 controls the adjustment motor 9 so that the rotation angle of the output shaft 9A is changed within the feed amount adjustment range RA.

[0109] 23, the moving knife 18 moves within a thread cutting operation range RB (second rotation range) where the rotation angle of the output shaft 9A of the adjustment motor 9 is equal to or larger than angle α1 and equal to or smaller than angle α2. Angle α2 is a value larger than α1 and smaller than 270°. In this embodiment, angle α2 is approximately 188°.

[0110] When the output shaft 9A rotates in the forward direction within the thread cutting operating range RB, the moving knife 18 moves so that the blade 31 of the moving knife 18 moves away from the counter knife 17. That is, when the output shaft 9A rotates in the forward direction so that the rotation angle of the output shaft 9A changes from angle α1 to angle α2, the moving knife 18 moves so that the blade 31 of the moving knife 18 moves away from the counter knife 17. After the moving knife 18 moves so that the blade 31 of the moving knife 18 moves away from the counter knife 17, the moving knife 18 moves so that the blade 31 of the moving knife 18 approaches the counter knife 17, whereby the upper thread and the lower thread are hooked onto the hook portion 30.

[0111] When the output shaft 9A rotates in the reverse direction within the thread cutting operating range RB, the moving knife 18 moves so that the blade 31 of the moving knife 18 approaches the counter knife 17. That is, when the output shaft 9A rotates in the reverse direction so that the rotation angle of the output shaft 9A changes from angle α2 to angle α1, the moving knife 18 moves so that the blade 31 of the moving knife 18 approaches the counter knife 17. When the moving knife 18 moves so that the blade 31 of the moving knife 18 approaches the counter knife 17, the upper thread and the lower thread are cut by the blade 31 of the moving knife 18 and the counter knife 17.

[0112] When the rotation angle of the output shaft 9A is within the feed amount adjustment range RA, the output shaft 9A rotates in the forward direction, causing the rotation angle of the output shaft 9A to transition from the feed amount adjustment range RA to the thread trimming operation range RB. The controller 14 controls the sewing machine motor 8 so that the thread cutter 6 can cut the upper thread and the bobbin thread, while controlling the adjustment motor 9 so that the rotation angle of the output shaft 9A transitions from the feed amount adjustment range RA to the thread trimming operation range RB.

[0113] When the operator wishes to finish sewing using the sewing machine 1, he or she operates the pedal 15 so that the rear portion of the pedal 15 moves downward. When the pedal 15 is operated so that the rear portion of the pedal 15 moves downward, the controller 14 starts processing to stop the sewing machine 1. When the pedal 15 is operated so that the rear portion of the pedal 15 moves downward, the controller 14 controls the sewing machine motor 8 so that the thread cutter 6 is in a state where it can cut the upper thread and the bobbin thread, and controls the adjustment motor 9 so that the rotation angle of the output shaft 9A moves from the feed amount adjustment range RA to the thread cutter operation range RB. After the rotation angle of the output shaft 9A moves from the feed amount adjustment range RA to the thread cutter operation range RB, the controller 14 rotates the output shaft 9A in the forward direction within the thread cutter operation range RB. As the output shaft 9A rotates in the forward direction, the moving knife 18 moves so that the blade 31 of the moving knife 18 moves away from the counter knife 17. After the moving knife 18 has moved so that the blade 31 of the moving knife 18 is separated from the counter knife 17, the output shaft 9A rotates in the reverse direction, causing the moving knife 18 to move so that the blade 31 of the moving knife 18 approaches the counter knife 17, and the upper thread and the lower thread are hooked by the hook portion 30 of the moving knife 18. After the moving knife 18 has moved so that the blade 31 of the moving knife 18 is separated from the counter knife 17, the controller 14 rotates the output shaft 9A in the reverse direction within the thread cutting operating range RB. As the output shaft 9A rotates in the reverse direction, the moving knife 18 moves so that the blade 31 of the moving knife 18 approaches the counter knife 17, and the upper thread and the lower thread are cut by the blade 31 of the moving knife 18 and the counter knife 17.

[0114] The roller 45 of the thread cutting mechanism 13 is disposed in the cam groove 33 of the cam 32. As shown in Figure 23, the shape of the cam groove 33 is determined so that the thread cutter 6 will not operate when the rotation angle of the output shaft 9A is within the feed amount adjustment range RA.

[0115] 23, even when the rotation angle of the output shaft 9A is within the thread cutting operation range RB, the feed amount adjuster 67 rotates to change the feed amount of the feed dog 5. In this embodiment, the rotation angle of the output shaft 9A is shifted from the feed amount adjustment range RA to the thread cutting operation range RB when the sewing machine motor 8 is controlled so that the thread cutter 6 can cut the upper thread and the bobbin thread. When the rotation angle of the output shaft 9A is within the thread cutting operation range RB, the thread cutter 6 can operate smoothly.

[0116] The range of the rotation angle of the output shaft 9A between the angle α2 and 360° is a non-use range RC in which neither the feed dog 5 nor the thread cutter 6 operates.

[0117] 24 is a timing chart for explaining the operations of the thread cutting mechanism 13 and the feed amount adjustment mechanism 25 according to the embodiment. FIG. 24 shows the relationship between the rotation angle of the upper shaft 19 and the thread cutting mechanism 13 and the feed amount adjustment mechanism 25.

[0118] In Figure 24, the horizontal axis represents the rotation angle of the upper shaft 19. The vertical axis represents the feed amount and feed direction of the feed dog 5 and the position of the moving knife 18. In Figure 24, line Ld represents the relationship between the rotation angle of the upper shaft 19 and the feed amount and feed direction of the feed dog 5. Line Le represents the relationship between the rotation angle of the upper shaft 19 and the position of the moving knife 18.

[0119] 24 shows an example in which the feed dog 5 advances the fabric by a feed amount of 3 mm during sewing using the sewing machine 1. The shape of the cam groove 33 is determined so that the thread cutter 6 does not operate during sewing using the sewing machine 1.

[0120] When the operator wishes to finish sewing using the sewing machine 1, he or she operates the pedal 15 so that the rear portion of the pedal 15 moves downward. When the pedal 15 is operated so that the rear portion of the pedal 15 moves downward, the controller 14 starts a process to stop the sewing machine 1. The controller 14 controls the sewing machine motor 8 so that the rotation angle of the upper shaft 19 becomes angle β1.

[0121] Next, the controller 14 controls the adjustment motor 9 to rotate the output shaft 9A so that the feed amount of the feed dog 5 reaches its maximum value. The controller 14 also controls the sewing machine motor 8 to rotate the upper shaft 19 so that the thread cutter 6 can cut the upper thread and the bobbin thread. The controller 14 controls the sewing machine motor 8 so that the upper shaft 19 rotates in synchronization with the rotation of the output shaft 9A. In the example shown in FIG. 24 , the rotation angle of the upper shaft 19 when the feed amount of the feed dog 5 reaches its maximum value is angle β2.

[0122] When the rotation angle of the upper shaft 19 is angle β2, the thread cutter 6 is ready to cut the upper thread and the bobbin thread. The state in which the thread cutter 6 is ready to cut the upper thread and the bobbin thread includes a state in which the sewing machine needle 3 is released from the fabric and a triangular loop of the upper thread and the bobbin thread is formed, into which the moving knife 18 can enter.

[0123] After the feed amount of the feed dog 5 reaches its maximum value and the rotation angle of the upper shaft 19 reaches angle β2, the controller 14 further rotates the output shaft 9A in the forward direction so that the moving knife 18 moves from the initial position to the most forward position. The controller 14 also rotates the upper shaft 19 in synchronization with the rotation of the output shaft 9A. The rotation angle of the upper shaft 19 when the moving knife 18 is disposed at the initial position is angle β2. The rotation angle of the upper shaft 19 when the moving knife 18 moves to the most forward position is angle β3. After the moving knife 18 moves to the most forward position, the moving knife 18 moves to the most rearward position, whereby the upper thread and the bobbin thread are hooked by the hook portion 30 of the moving knife 18.

[0124] After the rotation angle of the upper shaft 19 reaches angle β4, the controller 14 rotates the output shaft 9A in the reverse direction so that the moving knife 18 moves from the most forward position to the initial position. When the moving knife 18 moves to the initial position, the upper thread and the lower thread are cut by the blade 31 of the moving knife 18 and the fixed knife 17. The rotation angle of the upper shaft 19 when the moving knife 18 moves to the initial position is angle β5.

[0125] After the moving knife 18 moves to the initial position and the rotation angle of the upper shaft 19 reaches angle β5, the controller 14 stops the sewing machine motor 8. In addition, the controller 14 controls the adjustment motor 9 so that the feed amount of the feed dog 5 returns to 3 mm, and then stops the adjustment motor 9.

[0126] [effect] As described above, the sewing machine 1 according to the embodiment comprises the sewing machine motor 8, the adjustment motor 9, the thread cutter 6 having the fixed knife 17 and the moving knife 18, the feed dog 5 for feeding the fabric forward or backward, the up and down feed mechanism 22 for moving the feed dog 5 back and forth in the up and down direction based on the rotational force generated by the sewing machine motor 8, the horizontal feed mechanism 24 for moving the feed dog 5 back and forth in the back and forth direction based on the rotational force generated by the sewing machine motor 8, the thread cutter mechanism 13 for moving the moving knife 18 based on the rotational force generated by the adjustment motor 9, and the feed amount adjustment mechanism 25 for changing the feed amount and feed direction of the feed dog 5 based on the rotational force generated by the adjustment motor 9.

[0127] According to the embodiment, the thread cutting mechanism 13 and the feed amount adjustment mechanism 25 are actuated by the rotational force generated by one adjustment motor 9. This prevents the structure of the sewing machine 1 from becoming complicated. Also, since an increase in the number of adjustment motors 9 mounted on the sewing machine 1 is prevented, the size of the sewing machine 1 is prevented from increasing. Also, since an increase in the number of adjustment motors 9 mounted on the sewing machine 1 is prevented, noise generated from the sewing machine 1 is prevented. Also, since an increase in the number of adjustment motors 9 mounted on the sewing machine 1 is prevented, power consumption from the sewing machine 1 is prevented.

[0128] The thread cutting mechanism 13 and the feed amount adjustment mechanism 25 are each connected to the output shaft 9A of the adjustment motor 9. When the rotation angle of the output shaft 9A is within the feed amount adjustment range RA, the feed amount and feed direction of the feed dog 5 are changed. When the rotation angle of the output shaft 9A is within the thread cutting operation range RB, the moving knife 18 moves. According to the embodiment, the thread cutting mechanism 13 and the feed amount adjustment mechanism 25 each operate smoothly.

[0129] In the process of stopping the sewing machine 1, the sewing machine motor 8 is controlled so that the thread cutter 6 can cut the upper thread and the bobbin thread, and the output shaft 9A rotates in the forward direction so that the rotation angle of the output shaft 9A moves from the feed amount adjustment range RA to the thread cutting operation range RB. According to the embodiment, the thread cutting mechanism 13 and the feed amount adjustment mechanism 25 each operate smoothly.

[0130] When the output shaft 9A rotates in the forward direction from the intermediate angle αm of the feed amount adjustment range RA, the feed amount of the fabric sent forward increases. When the output shaft 9A rotates in the reverse direction from the intermediate angle αm of the feed amount adjustment range RA, the feed amount of the fabric sent backward increases. According to the embodiment, the feed amount and feed direction of the feed dog 5 can be smoothly changed simply by changing the rotation direction and rotation amount of the output shaft 9A.

[0131] When the output shaft 9A rotates in the forward direction in the thread cutting operating range RB, the moving knife 18 moves so that the blade 31 of the moving knife 18 moves away from the counter knife 17. When the output shaft 9A rotates in the reverse direction in the thread cutting operating range RB, the moving knife 18 moves so that the blade 31 of the moving knife 18 moves closer to the counter knife 17. According to the embodiment, the thread cutter 6 is operated simply by changing the direction and amount of rotation of the output shaft 9A.

[0132] The sewing machine 1 includes a cam 32 fixed to the output shaft 9A of the adjustment motor 9. The thread cutting mechanism 13 and the feed amount adjustment mechanism 25 are each connected to the cam 32. According to the embodiment, the rotation of the cam 32 allows the thread cutting mechanism 13 and the feed amount adjustment mechanism 25 to operate smoothly.

[0133] The cam 32 has a cam groove 33. The thread cutting mechanism 13 has a roller 45 disposed in the cam groove 33, a thread cutting arm 34 rotatably supported by the roller 45, and a drive link 35 rotatably connected to the tip of the thread cutting arm 34. The feed amount adjustment mechanism 25 has a first link 65 rotatably connected to the right end face of the cam 32, an adjustment arm 66 connected to the first link 65, and a feed amount adjuster 67 connected to the adjustment arm 66. The moving knife 18 moves by rotation of the drive link 35. The feed amount and feed direction of the feed dog 5 are changed by rotation of the feed amount adjuster 67. According to this embodiment, the thread cutting mechanism 13 and the feed amount adjustment mechanism 25 each operate smoothly. [Explanation of symbols]

[0134] 1...sewing machine, 2...sewing machine frame, 2A...arm, 2B...bed, 2C...base, 2D...head, 3...sewing machine needle, 4...needle bar, 5...feed dog, 6...thread cutter, 7...support member, 7L...support member, 7R...support member, 8...sewing machine motor, 9...adjusting motor, 9A...output shaft, 10...needle bar drive mechanism, 11...material feed mechanism, 12...belt mechanism, 13...thread cutter mechanism, 14...controller, 15...pedal, 16...operation panel, 17...counter knife, 17L...counter knife, 17R...counter knife, 18...moving knife, 18L...moving knife, 18R...moving knife, 19...upper shaft, 20...conversion mechanism, 2 1...vertical feed shaft, 22...vertical feed mechanism, 23...horizontal feed shaft, 24...horizontal feed mechanism, 25...feed amount adjustment mechanism, 26...horizontal feed connecting rod, 27...upper pulley, 28...lower pulley, 29...timing belt, 30...hook portion, 31...blade, 32...cam, 32A...fixing hole, 32B...insertion hole, 33...cam groove, 34...thread trimmer arm, 35...driving link, 35A...first driving link, 35B...second driving link, 35C...long hole, 35D...screw, 36...right rotating link (first rotating link), 37...synchronous link, 37A...first synchronous link, 37B...second synchronous link link, 37C...long hole, 37D...screw, 38...left rotating link (second rotating link), 39...right rod, 40...left rod, 41...right slide link (first slide link), 42...left slide link (second slide link), 43...right movable member (first movable member), 43A...slider portion, 43B...fixed portion, 44...left movable member (second movable member), 44A...slider portion, 44B...fixed portion, 45...roller, 46...shoulder screw, 47...joint, 48...joint, 49...pivot, 50...joint, 51...joint, 52...pivot, 53...right slide pin (first slide guide pin), 54...left slide pin (second slide pin), 55...guide groove, 56...long hole, 57...guide groove, 58...long hole, 59...feed table, 59A...holding portion, 59B...connecting portion, 60...vertical feed eccentric cam, 61...vertical feed connecting rod, 62...horizontal feed arm, 63...horizontal feed eccentric cam, 65...first link, 65A...first hole, 65B...second hole, 66...adjusting arm, 66A...insertion hole, 66B...insertion hole, 67...feed amount adjusting body, 67A...rod portion, 68...second link, 69...oscillating arm, 70...step screw, 71...pin, 72...screw, 90...motor base,AX1...rotating axis, AX2...rotating axis, AX3...rotating axis, AX4...rotating axis, AX5...rotating axis, AX6...rotating axis, AX7...rotating axis, RA...feed amount adjustment range (first rotation range), RB...thread trimming operating range (second rotation range), RC...non-use range.

Claims

1. A sewing machine motor; an adjustment motor; a thread cutter having a fixed knife and a moving knife; A feed dog that feeds the fabric forward or backward; a vertical feed mechanism that reciprocates the feed dog in the vertical direction based on the rotational force generated by the sewing machine motor; a horizontal feed mechanism that reciprocates the feed dog in the front-to-rear direction based on the rotational force generated by the sewing machine motor; a thread cutting mechanism that moves the moving knife based on the rotational force generated by the adjustment motor; a feed amount adjustment mechanism that changes the feed amount and feed direction of the feed dog based on the rotational force generated by the adjustment motor. sewing machine.

2. the thread cutting mechanism and the feed amount adjustment mechanism are each connected to an output shaft of the adjustment motor; When the rotation angle of the output shaft is within a first rotation range, the feed amount and the feed direction of the feed dog are changed, The moving knife moves when the rotation angle of the output shaft is in a second rotation range.

2. The sewing machine according to claim 1.

3. When the output shaft rotates in the positive direction, the rotation angle of the output shaft transitions from the first rotation range to the second rotation range.

3. The sewing machine according to claim 2.

4. When the output shaft rotates in the positive direction from the intermediate angle of the first rotation range, the feed amount of the fabric forward increases, When the output shaft rotates in the reverse direction from the intermediate angle of the first rotation range, the feed amount of the fabric sent rearward increases.

4. The sewing machine according to claim 3.

5. When the output shaft rotates in the forward direction within the second rotation range, the moving knife moves so that the blade of the moving knife moves away from the counter knife, When the output shaft rotates in the opposite direction within the second rotation range, the moving knife moves so that the blade of the moving knife approaches the counter knife.

4. The sewing machine according to claim 3.

6. a cam fixed to the output shaft of the adjustment motor; The thread cutting mechanism and the feed amount adjustment mechanism are each connected to the cam.

2. The sewing machine according to claim 1.

7. The cam has a cam groove, The thread cutting mechanism is a roller disposed in the cam groove; a thread cutting arm rotatably supported on the roller; a drive link rotatably connected to the tip end of the thread cutting arm, The feed amount adjustment mechanism includes: a first link rotatably connected to an end surface of the cam; an adjustment arm connected to the first link; a feed amount adjusting body connected to the adjusting arm, The moving knife is moved by the rotation of the drive link, The feed amount and feed direction of the feed dog are changed by rotating the feed amount adjusting body.

7. The sewing machine according to claim 6.

8. The thread cutting mechanism is a first rotating link rotatably connected to a tip end of the drive link; a first slide link connected to the first pivot link and having a first slide pin; a first movable member having an elongated hole into which the first slide pin is inserted, The moving knife is fixed to the first movable member.

8. The sewing machine according to claim 7.

9. The thread cutting mechanism is a synchronous link rotatably connected to a tip end of the first rotary link; a second rotating link rotatably connected to a tip end of the synchronous link; a second slide link connected to the second pivot link and having a second slide pin; a second movable member having an elongated hole into which the second slide pin is inserted, Two moving knives are provided, One of the moving knives is fixed to the first movable member, The other moving knife is fixed to the second movable member.

9. The sewing machine according to claim 8.

10. The vertical feed mechanism is a vertical feed shaft that rotates based on the rotational force generated by the sewing machine motor; a vertical feed eccentric cam fixed to the left end of the vertical feed shaft; a vertical feed connecting rod attached to the vertical feed eccentric cam and connected to a feed table that holds the feed dog; The horizontal feed mechanism includes: a horizontal feed shaft connected to the vertical feed shaft via the feed amount adjustment mechanism; a horizontal feed arm fixed to the left end of the horizontal feed shaft and connected to the slide; The feed amount adjustment mechanism includes: a horizontal feed connecting rod connected to each of the vertical feed shaft and the feed amount adjusting body, and reciprocating in the front-rear direction with full rotation of the vertical feed shaft; a second link rotatably connected to the feed amount adjuster; a swing arm connected to each of the horizontal feed shaft and the second link; 8. The sewing machine according to claim 7.

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