Sewing machine

Abstract

To provide a sewing machine enabling size of a clearance formed on a stopper to be changed.SOLUTION: A shuttle mechanism 20 has an enclosure 20A, an outer shuttle 24, an inner shuttle 25, and a stopper 30. The stopper 30 has a fixing member 31 including an abutment part 37, and a movable member 32 including an abutment part 38. The abutment part 37 and the abutment part 38 face each other in a longitudinal direction. A shuttle stop part 26 extending from a base part 25A of the inner shuttle 25 is inserted in a clearance S formed between the abutment part 37 and the abutment part 38. The abutment part 37 regulates normal rotation of the inner shuttle 25 by abutting against the shuttle stop part 26. The abutment part 38 regulates a reverse rotation of the inner shuttle 25 by abutting against the shuttle stop part 26. The fixing member 31 is fixed to a groove 20E of the enclosure 20A. The movable member 32 is provided so as to be movable in the longitudinal direction by driving of a direct acting cylinder 34.SELECTED DRAWING: Figure 4

Description

[Technical field]

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

[0002] A hook device for a sewing machine that restricts the rotation of the inner hook within a certain range is known. For example, the hook device described in Patent Document 1 has a needle plate, an outer hook, and an inner hook. A pair of stoppers are provided at the lower end of the needle plate with a gap between them. The outer hook is rotatable around a vertical axis. The inner hook is housed in the outer hook and is rotatable relative to the outer hook. A hook stopper is provided on the outer periphery of the inner hook. The hook stopper is inserted into the gap formed between the pair of stoppers. The hook stopper comes into contact with the pair of stoppers, restricting the rotation of the inner hook within a certain range. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-299645 Summary of the Invention [Problem to be solved by the invention]

[0004] The shuttle device captures the upper thread passing through the sewing needle and entangles it with the lower thread. If the gap formed between the pair of stoppers is too narrow, the upper thread may get caught on the pair of stoppers and untwist. If the gap is too wide, the rotation of the inner shuttle may not be sufficiently suppressed. Therefore, it is desirable for the shuttle device to be able to change the size of the gap.

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a sewing machine in which the size of the gap formed in the stopper can be changed. [Means for solving the problem]

[0006] A sewing machine according to one aspect of the present invention includes a shuttle mechanism that captures an upper thread passing through a sewing needle and entangles it with a lower thread, the shuttle mechanism including an outer shuttle including a point capable of capturing the upper thread and rotatable about an axis extending in a vertical direction, an inner shuttle that stores the lower thread and is rotatable about the axis relative to the outer shuttle inside the outer shuttle, a shuttle stopper connected to an outer periphery of the inner shuttle and rotatable about the axis integrally with the inner shuttle, the shuttle stopper extending in a first direction among radial directions centered on the axis, and a stopper having a first member and a second member; The first member has a first contact portion capable of contacting the shuttle stopper part rotating in a forward rotation about the axis, and the second member has a second contact portion capable of contacting the shuttle stopper part rotating in a reverse rotation opposite to the forward rotation, the first contact portion and the second contact portion face each other in a second direction that intersects with the first direction and is horizontal, and the size of a gap formed between the first contact portion and the second contact portion can be changed by moving at least one of the first member and the second member in the second direction.

[0007] According to the above aspect, in the sewing machine, the stopper restricts the rotation of the shuttle stopper around the axis by the first contact portion and the second contact portion. The sewing machine can change the size of the gap formed between the first contact portion and the second contact portion by moving at least one of the first member and the second member in the second direction.

[0008] The sewing machine according to one aspect of the present invention may include a drive unit connected to at least one of the first member or the second member and moving the at least one of the first member or the second member in the second direction, and a control unit that controls the movement of the at least one of the first member or the second member in the second direction by the drive unit when sewing using the shuttle mechanism. In this case, the sewing machine can easily change the size of the gap between the stoppers compared to a case in which the at least one of the first member or the second member is not moved by the drive unit.

[0009] In a sewing machine according to one aspect of the present invention, the drive unit may be connected to the second member. In the sewing machine, the shuttle stopper often rotates forward together with the shuttle, and therefore is likely to abut against the first abutment of the first member. The sewing machine moves the second member of the first and second members to change the size of the gap through which the stopper is inserted. Thus, the sewing machine can effectively restrict the rotation of the shuttle stopper and the shuttle about their axes.

[0010] In the sewing machine according to one aspect of the present invention, the drive unit may be a linear cylinder. In this case, the sewing machine can change the size of the gap between the stoppers with a simple structure.

[0011] In a sewing machine according to one aspect of the present invention, when starting sewing, the control means may move the second member, which is disposed at an initial position, in a direction in the second direction in which the gap becomes larger, by the drive unit, to place the second member at the first sewing position. During sewing by the sewing machine, the upper thread may get caught on the second contact portion and untwist. Since the gap is widened when sewing starts, the upper thread is less likely to get caught on the second contact portion during sewing by the sewing machine. Thus, the sewing machine can prevent the upper thread from untwisting.

[0012] In the sewing machine according to one aspect of the present invention, the control means may, when finishing sewing, move the second member, which is disposed at the first sewing position, in the second direction in which the gap becomes smaller by the drive unit, to place the second member at the initial position. In this case, the sewing machine moves the second member to make the gap smaller when finishing sewing, so that the rotation of the shuttle stopper and the shuttle about the axis can be well restricted when sewing is not being performed.

[0013] A sewing machine according to one aspect of the present invention includes a determination means for determining a direction of movement from the position of an Nth needle (N is a natural number) in a sewing object to the position of an N+1th needle, and a determination means for determining whether the direction of movement determined by the determination means is within a predetermined range. When the determination means determines that the direction of movement is within the predetermined range, the control means may move the second member disposed at the first sewing position in the second direction to a second sewing position different from the first sewing position when starting sewing of the N+1th stitch. When the sewing machine moves the direction of movement in sewing within the predetermined range, a hitch stitch may occur, which may cause an imbalance in tension between the upper thread and the lower thread. The hitch stitch is caused by the relative positions of the upper thread and the lower thread. The sewing machine moves the second member from the first sewing position to the second sewing position to change the relative positions of the upper thread and the lower thread. This allows the sewing machine to suppress the occurrence of a hitch stitch.

[0014] In a sewing machine according to an aspect of the present invention, the second sewing position is a position of the second member that is moved by the drive unit in the second direction in which the gap becomes smaller, and the control unit may not move the second member that is placed at the first sewing position to the second sewing position when the value of N+1 is equal to or less than a predetermined value M (M is a natural number equal to or greater than 2). In the sewing machine, the upper thread may be caught on the second contact portion and untwisted at the start of sewing. When the number of needles is equal to or less than a predetermined number, the second member is not moved from the first sewing position to the second sewing position as it is the start of sewing, so that the upper thread is less likely to be caught on the second contact portion at the start of sewing. Thus, the sewing machine can suppress the occurrence of hitch stitches while suppressing untwisting of the upper thread at the start of sewing.

[0015] In a sewing machine according to one aspect of the present invention, the lower end of the first contact portion and the lower end of the second contact portion may be located above the tip, and the lower end of the second contact portion may be located above the lower end of the first contact portion. During sewing with the sewing machine, the upper thread may get caught on the second contact portion and untwist. Since the lower end of the second contact portion is located above the lower end of the first contact portion, the sewing machine can prevent the upper thread from getting caught on the second contact portion and untwisting the upper thread. [Brief description of the drawings]

[0016] [Figure 1] FIG. [Diagram 2] 2 is a perspective view of the head 6 and the shuttle mechanism 20. FIG. [Diagram 3] 3 is a partially enlarged view of the head 6 and the shuttle mechanism 20 surrounded by the imaginary line III shown in FIG. 2. [Figure 4] FIG. [Diagram 5] FIG. [Figure 6] FIG. [Figure 7] 1 is a perspective view of the movable member 32 as viewed from above and to the front right. [Figure 8] 13 is a perspective view of the movable member 32 as viewed from below and the front right. [Figure 9] 1 is a right side view of the stopper 30 when the movable member 32 is located at the first position. [Figure 10] 2 is a plan view of the stopper 30 and the shuttle 23 when the movable member 32 is located at the first position. [Figure 11] 11 is a right side view of the stopper 30 when the movable member 32 is located at the second position. FIG. [Figure 12] 2 is a plan view of the stopper 30 and the shuttle 23 when the movable member 32 is located at the second position. FIG. [Figure 13] 13 is a plan view of the stopper 30 and the shuttle 23 when the lower thread R has slipped under the extending portion 32J. FIG. [Figure 14]13 is a diagram showing a perfect stitch area and a hitch stitch area when the movable member 32 is located in a first position. FIG. [Figure 15] 13 is a diagram showing a perfect stitch area and a hitch stitch area when the movable member 32 is located in a second position. FIG. [Figure 16] 2 is a block diagram showing the electrical configuration of the sewing machine 1. FIG. [Figure 17] 11 is a diagram showing a sewing object 99 to be sewn based on a sewing pattern. FIG. [Figure 18] 13 is a flowchart of a sewing process. [Figure 19] 13 is a flowchart of a stopper process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] A sewing machine 1 according to an embodiment of the present invention will be described with reference to the drawings. In the following description, arrows in the drawings will be used to indicate left and right, front and rear, and up and down.

[0018] <Overview of Sewing Machine 1> The sewing machine 1 is a gate-type sewing machine that sews a sewing object 99 (see FIG. 17). As shown in FIG. 1, the sewing machine 1 has a bed 2, an operating unit 8, a feed mechanism 4, pillars 3L and 3R, a beam 5, a head 6, a feed mechanism 7 (see FIG. 2), a synchronization mechanism 9 (see FIG. 2), and a shuttle mechanism 20.

[0019] The bed 2 has a base 2A and a frame 2B. The base 2A is a rectangular box in a plan view. A horizontally extending holding surface 2U is formed on the upper surface of the base 2A. An opening 2Q is formed in the base 2A, opening into the holding surface 2U and extending in the left-right direction. A sewing needle 11A, which will be described later, is inserted into the opening 2Q. A holding plate 2P is provided on the front end of the base 2A. The holding plate 2P extends forward from the front end of the base 2A along the holding surface 2U.

[0020] An opening 2L that exposes the holding surface 2U is formed at the left end of the base 2A. The opening 2L extends in the front-rear direction and is covered by a bellows 2C. An opening 2R that exposes the holding surface 2U is formed at the right end of the base 2A. The opening 2R extends in the front-rear direction and is covered by a bellows 2D. A pair of rails (not shown) that extend in the front-rear direction along the openings 2L and 2R are stored inside the base 2A. The bellows 2C and 2D expand and contract in response to the movement of the feed mechanism 4 (described later) in the front-rear direction. The frame 2B is a lattice-shaped structure that supports the base 2A from below.

[0021] The operation unit 8 is provided at the left front end of the base 2A. The operation unit 8 has an input unit 8A and a display unit 8B. The input unit 8A receives operations by an operator and inputs various instructions corresponding to the operator's operations to the control unit 50 (see FIG. 16). The display unit 8B is, for example, a liquid crystal display, and displays various images.

[0022] The feed mechanism 4 has coupling parts 4L and 4R. The coupling part 4L is connected to a rail extending along the opening 2L and protrudes above the holding surface 2U through the opening 2L. The coupling part 4R is connected to a rail extending along the opening 2R and protrudes above the holding surface 2U through the opening 2R. The coupling parts 4L and 4R are guided by a pair of rails and can move in the front-rear direction. The feed mechanism 4 is connected to a Y motor 73 (see FIG. 16) described later and moves in the front-rear direction by the drive of the Y motor 73. The coupling parts 4L and 4R are connected to the holding mechanism 4A above the holding surface 2U.

[0023] The holding mechanism 4A has an upper frame 4U, a lower frame 4V, and air cylinders 4C and 4D. The upper frame 4U and the lower frame 4V are rectangular frames when viewed from above. The upper frame 4U is provided above the lower frame 4V and is movable in the vertical direction. The upper frame 4U is connected to the air cylinders 4C and 4D and moves in the vertical direction by driving the air cylinders 4C and 4D. The upper frame 4U clamps a sewing workpiece 99 (see FIG. 17) placed on the lower frame 4V from above by driving the air cylinders 4C and 4D, and the sewing workpiece 99 is held by the holding mechanism 4A. The holding mechanism 4A moves the sewing workpiece 99 in the front-rear direction together with the feed mechanism 4.

[0024] The pillars 3L and 3R are rectangular pillar-shaped boxes. The pillar 3L extends upward from the base 2A at a position between the left end of the base 2A and the left end of the opening 2L. A main motor 71 (see FIG. 16), which will be described later, is housed inside the pillar 3L. The pillar 3R extends upward from the base 2A at a position between the right end of the base 2A and the right end of the opening 2R. An X-motor 72 (see FIG. 16), which will be described later, is housed inside the pillar 3R.

[0025] The beam 5 is installed between the leg pillars 3L and 3R. The beam 5 is a rectangular box that is long in the left-right direction when viewed from the front. An opening 5A extending in the left-right direction is formed in the front surface of the beam 5. The beam 5 has a bellows 5B and a pair of rails 5S (see FIG. 2). The bellows 5B covers the opening 5A and expands and contracts in response to the head 6, which will be described later, moving in the left-right direction. As shown in FIG. 2, the pair of rails 5S are rod-shaped extending in the left-right direction and are stored inside the beam 5. The pair of rails 5S are arranged vertically with a gap between them and support the head 6 so that it can move in the left-right direction.

[0026] The head 6 is provided in front of the beam 5 (see Figure 1). As shown in Figure 2, the head 6 has a housing 6A, a needle bar 11, a presser foot 12, a thread take-up 13, a thread tension controller 14, a sub-thread tension controller 15, and a drive mechanism 16. The housing 6A is box-shaped and houses the drive mechanism 16. The needle bar 11 is rod-shaped extending in the vertical direction, and is supported by the drive mechanism 16 so that it can move in the vertical direction. A sewing needle 11A is attached to the lower end of the needle bar 11. An upper thread is inserted into the sewing needle 11A.

[0027] Presser foot 12 is formed with a through hole 12A (see FIG. 3) through which sewing needle 11A, which moves vertically integrally with needle bar 11, passes. Presser foot 12 presses down on sewing workpiece 99 from above. Thread take-up lever 13 pulls up the upper thread in response to the vertical movement of needle bar 11. Thread tension regulator 14 adjusts the tension of the upper thread. Sub-thread tension regulator 15 adjusts the tension of the upper thread together with thread tension regulator 14.

[0028] The drive mechanism 16 has an upper shaft 17, a first support mechanism (not shown), a second support mechanism (not shown), a rotating knob 18, and a transmission mechanism 19. The upper shaft 17 is rod-shaped with an axis extending in the left-right direction, and is stored in the head 6. The right end of the upper shaft 17 protrudes rightward from the housing 6A. The upper shaft 17 is rotatable around its axis.

[0029] The first support mechanism and the second support mechanism are provided on the left end of upper shaft 17. The first support mechanism supports needle bar 11, and the second support mechanism supports balance 13. The first support mechanism and the needle bar 11 supported by the first support mechanism move up and down in response to the rotation of upper shaft 17. The second support mechanism and the balance 13 supported by the second support mechanism move up and down in response to the rotation of upper shaft 17.

[0030] The rotating knob 18 is provided at the right end of the upper shaft 17 and is a disk whose axis extends in the left-right direction. The axis of the rotating knob 18 is coaxial with the axis of the upper shaft 17. The rotating knob 18 is located outside the housing 6A and can be rotated about its axis by an operator. The transmission mechanism 19 transmits the drive of the spline shaft 9U, which will be described later, to the upper shaft 17, causing the upper shaft 17 to rotate about its axis.

[0031] The feed mechanism 7 has an X-motor 72 (see FIG. 16), a transmission mechanism (not shown), and belts 7U and 7V. The transmission mechanism of the feed mechanism 7 is housed inside the pillar 3R and transmits the drive of the X-motor 72 to the belts 7U and 7V. The belt 7U is housed inside the beam 5. One end of the belt 7U is connected to the transmission mechanism, and the other end of the belt 7U is connected to the rear end of the housing 6A. The belt 7U transmits the drive of the X-motor 72 to the head 6. The belt 7V is housed inside the base 2A. One end of the belt 7V is connected to the transmission mechanism, and the other end of the belt 7V is connected to the shuttle mechanism 20, which will be described later. The belt 7V transmits the drive of the X-motor 72 to the shuttle mechanism 20. The head 6 and the shuttle mechanism 20 move in the left-right direction by the drive of the X-motor 72.

[0032] The synchronization mechanism 9 has a main motor 71 (see FIG. 16), a transmission mechanism (not shown), and spline shafts 9U, 9V. The transmission mechanism of the synchronization mechanism 9 is housed inside the pillar portion 3L, and transmits the drive of the main motor 71 to the spline shafts 9U, 9V.

[0033] The spline shafts 9U, 9V are rod-shaped with an axis extending in the left-right direction, and have spline grooves extending in the left-right direction formed on their side surfaces. The spline shaft 9U is housed inside the beam portion 5. The spline shaft 9U is rotatable about its axis. The spline shaft 9U rotates about its axis and transmits the drive of the main motor 71 to the transmission mechanism 19. The spline shaft 9V is housed inside the base portion 2A. The spline shaft 9V is rotatable about its axis. The spline shaft 9V rotates about its axis and transmits the drive of the main motor 71 to the shuttle mechanism 20 described below.

[0034] <Kettle mechanism 20> The shuttle mechanism 20 is stored inside the base 2A (see FIG. 1). As shown in FIGS. 2 to 4, the shuttle mechanism 20 has a housing 20A, a drive mechanism 21, a shuttle 23, and a stopper 30. As shown in FIG. 2, the housing 20A is box-shaped and stores the drive mechanism 21 and the shuttle 23. The housing 20A is supported by a pair of rails 2S so as to be movable in the left-right direction. The pair of rails 2S are rod-shaped extending in the left-right direction. The pair of rails 2S are stored inside the base 2A and are arranged at a distance from each other in the front-rear direction.

[0035] As shown in Fig. 3, an opening 20C and a pair of grooves 20D and 20E are formed in the housing 20A. The opening 20C opens the top surface 20B of the housing 20A in the vertical direction. A hook 23, which will be described later, is stored inside the housing 20A through the opening 20C. The left end of the opening 20C is located between the left end of the housing 20A and the center of the housing 20A in the left-right direction. The right end of the opening 20C is located between the right end of the housing 20A and the center of the housing 20A in the left-right direction.

[0036] The pair of grooves 20D, 20E are formed by being recessed downward from the center in the left-right direction of the upper surface 20B. The pair of grooves 20D, 20E are located between both ends of the opening 20C in the left-right direction. The vertical depth of the pair of grooves 20D, 20E is smaller than the vertical depth of the opening 20C. The pair of grooves 20D, 20E are aligned with each other in the front-rear direction. The groove 20D is located at the front end of the housing 20A and in front of the opening 20C. The groove 20E is located at the rear end of the housing 20A and behind the opening 20C.

[0037] As shown in Fig. 4, the drive mechanism 21 has a lower shaft 22, a first transmission mechanism 21A, a second transmission mechanism (not shown), and a shuttle shaft (not shown). The lower shaft 22 is rod-shaped with an axis extending in the left-right direction, and is housed in the housing 20A. The right end of the lower shaft 22 protrudes rightward from the housing 20A. The lower shaft 22 is rotatable about its axis.

[0038] The first transmission mechanism 21A is connected to the right end of the lower shaft 22. The first transmission mechanism 21A transmits the drive of the spline shaft 9V to the lower shaft 22, causing the lower shaft 22 to rotate about its axis. The second transmission mechanism is connected to the lower shaft 22 and the shuttle shaft. Although not shown, the shuttle shaft is a rod-like shaft extending vertically, and is housed in the housing 20A through the opening 20C. The shuttle shaft is rotatable about its axis. The second transmission mechanism transmits the rotation of the lower shaft 22 about its axis to the shuttle shaft, causing the shuttle shaft to rotate about its axis.

[0039] The shuttle 23 is located between the right end of the opening 20C and the center of the housing 20A in the left-right direction. The shuttle 23 has an outer shuttle 24 and an inner shuttle 25. The outer shuttle 24 is housed inside the housing 20A through the opening 20C. The outer shuttle 24 has a base 24A and a tip 24C.

[0040] The base 24A is a cylinder whose axis extends vertically. The base 24A has an opening 24B that is circular in plan view and opens at the upper end of the base 24A. The lower end of the base 24A is connected to the upper end of the shuttle shaft. The axis of the base 24A coincides with the axis of the shuttle shaft. The outer shuttle 24 connected to the shuttle shaft rotates around the axis of the base 24A by being driven by the main motor 71. When the sewing machine 1 sews the workpiece 99, the outer shuttle 24 rotates clockwise in plan view. The clockwise rotation of the shuttle 23 in plan view is called forward rotation. The counterclockwise rotation of the shuttle 23 in plan view is called reverse rotation.

[0041] The tip 24C is rod-shaped and extends from the outer peripheral end of the base 24A in the forward rotation direction of the outer hook 24. The tip 24C has a sharp tip. When the sewing machine 1 sews the workpiece 99, the tip 24C captures the loop of the upper thread inserted in the sewing needle 11A.

[0042] The inner hook 25 has a base 25A, a support shaft 25D, a pressing portion 25E, and a hook stopper portion 26. The base 25A is a cylinder whose axis extends vertically, and is housed in the base 24A through the opening 24B. The axis of the base 25A coincides with the axis of the base 24A. The base 25A is rotatable relative to the outer hook 24. A space 25B is formed in the base 25A, which opens at the upper end of the base 25A. The space 25B is a cylinder whose axis extends vertically. A bobbin 29 around which the lower thread R is wound is housed inside the space 25B.

[0043] The support shaft 25D is rod-shaped and extends upward from the inner wall of the base 25A that defines the bottom of the space 25B. The axis of the support shaft 25D coincides with the axis of the base 24A. In the vertical direction, the position of the upper end of the support shaft 25D is approximately the same as the position of the upper end of the base 25A. The presser 25E is a plate that extends forward from the upper end of the support shaft 25D. The presser 25E presses the bobbin 29 stored in the space 25B from above, preventing the bobbin 29 from falling out of the inner hook 25. A recess 25F that is recessed toward the forward rotation direction of the outer hook 24 is formed at the front end of the presser 25E and the end in the reverse rotation direction of the outer hook 24. The lower thread R (see FIG. 10) wound around the bobbin 29 is hooked on the recess 25F and then extends toward the needle hole 33A described later.

[0044] The shuttle stopper portion 26 extends leftward from the outer peripheral end of the base portion 25A. More specifically, the shuttle stopper portion 26 is a plate that extends from the upper left end of the base portion 25A to the upper left and then extends leftward above the base portion 24A. The left end of the shuttle stopper portion 26 is to the left of the base portion 24A. The shuttle stopper portion 26 can rotate integrally with the inner shuttle 25. The inner shuttle 25 and the shuttle stopper portion 26 can rotate following the rotation of the outer shuttle 24, but the range of rotation is limited by a stopper 30 described later.

[0045] <Stopper 30> The structure of the stopper 30 will be described with reference to Fig. 3 to Fig. 8. As shown in Fig. 3, the stopper 30 is provided in the left-right center of the housing 20A and at the upper left of the shuttle 23. As shown in Fig. 5, the stopper 30 has fixed members 31, 36, a movable member 32, a pinhole member 33, a linear cylinder 34, and a connecting member 35.

[0046] The fixing member 31 is provided inside the groove 20E (see FIG. 3). As shown in FIG. 6, the fixing member 31 has a base portion 31A, a protruding portion 31B, and an extending portion 31C.

[0047] The base 31A is a rectangular plate in plan view. The base 31A is formed with a screw hole 31D and through holes 31E and 31F that penetrate the base 31A in the up-down direction. The screw hole 31D is formed closer to the right rear end than the center of the base 31A in plan view. The through hole 31E is formed closer to the right front end than the center of the base 31A in plan view, and the through hole 31F is formed closer to the left rear end than the center of the base 31A in plan view. The through holes 31E and 31F are stepped holes with a larger diameter on the upper side. The base 31A is fixed to the bottom of the groove 20E by a screw 43 (see FIG. 4) that is inserted from above through the through holes 31E and 31F. The head of the screw 43 is disposed inside the through holes 31E and 31F.

[0048] The protruding portion 31B is rod-shaped and extends forward from the right front end of the base portion 31A. The extending portion 31C is rod-shaped and extends forward from the front end of the protruding portion 31B. In the vertical direction, the position of the lower end of the extending portion 31C is substantially the same as the position of the lower end of the protruding portion 31B. The upper end of the extending portion 31C is higher than the upper end of the protruding portion 31B. The front end of the extending portion 31C is abutment portion 37 that is rectangular in front view and extends in the vertical direction.

[0049] As shown in FIG. 4, the fixing member 36 is a plate having a rectangular shape in plan view. A pair of through holes 36A is formed in the fixing member 36 at a position closer to the left front end and the right rear end than the center in plan view, penetrating the fixing member 36 in the vertical direction. A screw hole (not shown) is formed in the fixing member 36 at a position closer to the right front end than the center in plan view. FIG. 4 illustrates one of the pair of through holes 36A. The through hole 36A is a stepped hole with a larger diameter on the upper side. The fixing member 36 is fixed to the bottom of the groove 20E by a screw 44 (see also FIG. 5 and FIG. 12) that is inserted from above through the pair of through holes 36A. The head of the screw 44 is disposed inside the through hole 36A.

[0050] 7 and 8, the movable member 32 has a base 32A and an extension 32J. The base 32A is a plate that is rectangular in plan view and extends in the front-rear direction. The base 32A is formed with screw holes 32C, long holes 32D, 32E, grooves 32F, and through holes 32H. The screw holes 32C, long holes 32D, 32E, and through holes 32H penetrate the base 32A in the up-down direction.

[0051] The screw hole 32C is formed closer to the rear end than the center in the front-to-rear direction of the base 32A. The long hole 32D is formed closer to the front end than the center in the front-to-rear direction of the base 32A. The long hole 32E is formed between the screw hole 32C and the center in the front-to-rear direction of the base 32A. The long holes 32D and 32E extend in the front-to-rear direction.

[0052] The groove 32F is formed by being recessed upward from the lower surface 32B of the base 32A. The groove 32F extends in the left-right direction from the right end of the base 32A to a position between the left end of the base 32A and the center of the base 32A in the left-right direction. The through hole 32H is located inside the groove 32F in the front-rear direction. In the front-rear direction, the position of the front end of the through hole 32H is approximately the same as the position of the front end of the groove 32F. The rear end of the through hole 32H is located forward of the rear end of the groove 32F. The left end of the through hole 32H is located left of the left end of the groove 32F. The right end of the through hole 32H is located left of the right end of the groove 32F.

[0053] The extension portion 32J extends downward from the right front end of the bottom 32G (see FIG. 8) of the groove 32F. The extension portion 32J has a triangular prism shape extending in the front-rear direction. The right face of the extension portion 32J inclines downward and left. In the left-right direction, the position of the left end of the extension portion 32J is substantially the same as the position of the right end of the through-hole 32H. The lower end of the extension portion 32J is higher than the lower face 32B of the base portion 32A. The rear end of the extension portion 32J is the bottom face of the triangular prism extending in the front-rear direction, and is an abutment portion 38 consisting of a surface extending in the up-down direction. The abutment portion 38 is between both ends of the through-hole 32H in the front-rear direction.

[0054] As shown in FIG. 5, the pinhole member 33 has a base 33B, a protruding portion 33C, an extending portion 33D, and a cylindrical portion 33E. The base 33B is located below the through hole 32H. The base 33B is a plate extending in the front-rear direction. The base 33B is fixed to the housing 20A. The protruding portion 33C extends upward from the upper end of the base 33B. The protruding portion 33C passes through the through hole 32H. The upper end of the protruding portion 33C is located below the upper end of the base 32A (see FIG. 4).

[0055] The extending portion 33D is a plate-like member extending rightward from the upper right end of the protruding portion 33C. In the left-right direction, the length of the extending portion 33D is approximately the same as the length of the through hole 32H. The length of the protruding portion 33C and the extending portion 33D in the front-rear direction is smaller than the length of the through hole 32H in the left-right direction. That is, the extending portion 33D is accommodated inside the through hole 32H.

[0056] The cylindrical portion 33E is located at the center of the extending portion 33D in the front-rear direction and the left-right direction. The cylindrical portion 33E is a cylinder extending upward and downward from the extending portion 33D. A needle hole 33A that passes through the cylindrical portion 33E and the extending portion 33D in the up-down direction is formed in the cylindrical portion 33E and the extending portion 33D. The needle hole 33A is located to the left of the contact portions 37, 38 (see FIG. 10). The sewing needle 11A that moves in the up-down direction is inserted through the needle hole 33A.

[0057] The linear cylinder 34 is provided behind the movable member 32 (see FIG. 4). As shown in FIG. 5, the linear cylinder 34 is a known air cylinder, and includes a housing 34A, a rod 34B, and an extension 34C. The housing 34A is box-shaped, and houses a cylinder (not shown) that moves in the front-rear direction by air. A hole 34D is formed in the front surface of the housing 34A.

[0058] Rod 34B is fixed to the cylinder and protrudes forward from housing 34A through hole 34D. Rod 34B is movable in the front-rear direction relative to housing 34A. Extension 34C is rod-shaped and extends forward from the front end of rod 34B. A screw hole (not shown) penetrating vertically is formed in a portion of extension 34C from the center in the front-rear direction toward the front end.

[0059] 5, the connection member 35 is a plate extending in the front-rear direction, and is located between the movable member 32 and the extension portion 34C in the up-down direction. Holes (not shown) penetrating the connection member 35 in the up-down direction are formed in a portion of the connection member 35 from the center in the front-rear direction toward the front end and a portion of the connection member 35 from the center in the front-rear direction toward the rear end, respectively.

[0060] A stepped screw 41A is inserted from below into a hole on the front end side of the connecting member 35. A threaded portion of the stepped screw 41A protrudes above the connecting member 35 and is screwed into a threaded hole 32C of the movable member 32. The connecting member 35 is rotatable around the stepped screw 41A relative to the movable member 32. A stepped screw 41B is inserted from above into a hole on the rear end side of the connecting member 35. A threaded portion of the stepped screw 41B protrudes below the connecting member 35 and is screwed into a threaded hole of the extension portion 34C. The connecting member 35 is rotatable around the stepped screw 41B relative to the extension portion 34C. The movable member 32 is connected to the linear cylinder 34 via the connecting member 35.

[0061] The movable member 32 is located above the fixed members 31, 36. A stepped screw 42A is inserted from above into the long hole 32D. A threaded portion of the stepped screw 42A protrudes downward from the lower surface 32B and is screwed into a threaded hole of the fixed member 36. A stepped screw 42B is inserted from above into the long hole 32E. A threaded portion of the stepped screw 42B protrudes downward from the lower surface 32B and is screwed into a threaded hole 31D (see FIG. 6) of the fixed member 31. The position of the upper end of the abutment portion 37 is approximately the same as the position of the bottom 32G of the groove 32F in the vertical direction (see FIG. 9).

[0062] As shown in Fig. 3, in the stopper 30, the abutment portion 37 of the fixed member 31 and the abutment portion 38 of the movable member 32 face each other in the front-rear direction. A gap S is formed between the abutment portions 37 and 38. The shuttle stopper portion 26 of the inner shuttle 25 is inserted into the gap S. When the inner shuttle 25 rotates forward, the shuttle stopper portion 26 abuts against the abutment portion 37, and the forward rotation of the inner shuttle 25 is restricted. When the inner shuttle 25 rotates reversely, the shuttle stopper portion 26 abuts against the abutment portion 38, and the reverse rotation of the inner shuttle 25 is restricted. In other words, the rotation range of the inner shuttle 25 is determined based on the size of the gap S.

[0063] As shown in Fig. 4, the lower ends of the contact parts 37 and 38 are located above the tip 24C. Therefore, the contact parts 37 and 38 do not hinder the rotation of the outer hook 24. The lower end of the contact part 38 is located above the lower end of the contact part 37 (see Fig. 9).

[0064] <Movement of Movable Member 32> The movable member 32 moves in the front-rear direction while being guided by shoulder screws 42A, 42B by the drive of the linear cylinder 34. The movable member 32 moves to a first position shown in Figures 9 and 10 and a second position shown in Figures 11 and 12.

[0065] As shown in Fig. 9, when the movable member 32 is in the first position, the position of the abutment portion 38 is forward of the axis C of the needle hole 33A in the front-rear direction. As shown in Fig. 10, the lower thread R extending from the recess 25F extends straight to the left rear toward the needle hole 33A. The lower thread R is inserted into the needle hole 33A from below. The abutment portion 38 is spaced forward from the lower thread R.

[0066] As shown in Fig. 11, when the movable member 32 is in the second position, the position of the abutment portion 38 is substantially the same as the position of the axis C of the pinhole 33A in the front-rear direction. As shown in Fig. 12, the movable member 32 in the second position is further rearward than the movable member 32 in the first position (see Fig. 10). Therefore, the size of the gap S when the movable member 32 is in the second position is smaller than the size of the gap S when the movable member 32 is in the first position. When the movable member 32 is in the second position, the rotation range of the inner shuttle 25 and the shuttle stopper portion 26 around the axis is smaller than when the movable member 32 is in the second position.

[0067] The lower thread R extending from the recess 25F extends left rear toward the contact portion 38, then turns left along the contact portion 38 and extends toward the needle hole 33A. The lower thread R is inserted into the needle hole 33A from below. When the sewing machine 1 is not sewing, the movable member 32 is in the second position.

[0068] When the movable member 32 moves from the second position to the first position, the contact portion 38 moves forward away from the lower thread R. On the other hand, when the movable member 32 moves from the first position to the second position, the contact portion 38 comes into contact with the lower thread R and pushes the lower thread R rearward. In this way, by switching the movable member 32 between the first position and the second position, the stopper 30 can change the path of the lower thread R to the needle hole 33A and change the position of the lower thread R relative to the upper thread passing through the sewing needle 11A.

[0069] When the sewing machine 1 sews, the appearance quality of the stitch changes depending on the direction of travel from the position of the Nth needle (N is a natural number) to the position of the N+1th needle. This is because the relative positions of the upper thread and the lower thread R change depending on the direction of travel. A method for deriving the direction of travel will be described later. In the sewing machine 1, there are directions in which the travel direction results in a perfect stitch and a hitch stitch. A perfect stitch is a stitch formed when the upper thread and the lower thread R are entangled in a state where they are evenly entangled. When a perfect stitch is formed, the thread tightening is good. A hitch stitch is a stitch formed when the tension of the upper thread is weak and the threads are entangled in a state where the balance with the tension of the lower thread R is lost. When a hitch stitch is formed, only the upper thread forms a stitch in a spiral shape, and the stitch quality is reduced.

[0070] As shown in Figs. 14 and 15, when the position of the Nth needle is the base point O, the direction of travel from the base point O to the position of the N+1th needle is in the range of 0° to 360°. In the sewing machine 1, the direction of travel backward is 0° (360°), the direction of travel rightward is 90°, the direction of travel forward is 180°, and the direction of travel leftward is 270°. In Figs. 14 and 15, the area of ​​the travel direction that results in a perfect stitch is shown in white, and the area of ​​the travel direction that results in a hitch stitch is shown in black. Hereinafter, the area of ​​the travel direction that results in a perfect stitch is referred to as the perfect stitch area. The area of ​​the travel direction that results in a hitch stitch is referred to as the hitch stitch area.

[0071] In the sewing machine 1, the hitch stitch area is different when the movable member 32 is located at the first position (see FIG. 14) from when the movable member 32 is located at the second position (see FIG. 15). This is because the positional relationship between the upper thread and the lower thread R changes due to the contact portion 38 of the movable member 32. In the sewing machine 1, the hitch stitch area when the movable member 32 is located at the second position does not overlap with the hitch stitch area when the movable member 32 is located at the first position. Therefore, the sewing machine 1 can prevent the formation of a hitch stitch by switching the movable member 32 between the first position and the second position. Hereinafter, the hitch stitch area when the movable member 32 is located at the first position is referred to as the hitch stitch area at the first position.

[0072] The tension of the upper thread at the start of sewing in the sewing machine 1 is smaller than the tension of the upper thread after the start of sewing. In the sewing machine 1, the start of sewing is from the 1st needle to the Mth needle. M is a natural number of 2 or more and is stored in the ROM 52 described later. When the movable member 32 is in the second position and the start of sewing is being performed, the lower thread R may slip under the extension portion 32J (see FIG. 13). At this time, the loop of the upper thread may get caught on the abutting portion 38, which may cause sewing defects such as untwisting of the upper thread.

[0073] When sewing starts, the sewing machine 1 moves the movable member 32 from the second position to the first position. The sewing machine 1 does not move the movable member 32 to the second position while starting sewing. When the movable member 32 is in the first position, the abutting portion 38 is located behind the lower thread R that extends straight from the recess 25F to the needle hole 33A (see FIG. 10). Therefore, the sewing machine 1 can prevent the lower thread R from slipping under the extension portion 32J at the start of sewing, which causes poor sewing.

[0074] When the sewing start is completed, the sewing machine 1 determines whether the moving direction from the sewn Nth needle to the N+1th needle is within the hitch stitch area at the first position. If the moving direction is within the hitch stitch area at the first position, the sewing machine 1 moves the movable member 32 from the first position to the second position. After that, if the moving direction is a perfect stitch area at the first position, the sewing machine 1 moves the movable member 32 from the second position to the first position. When the sewing machine 1 finishes sewing, it places the movable member 32 at the second position.

[0075] <Electrical configuration of sewing machine 1> 16, the control unit 50 of the sewing machine 1 includes a CPU 51, a ROM 52, a RAM 53, a storage device 54, an input / output interface (I / O) 55, and drive circuits 61 to 65. The CPU 51 controls the overall operation of the sewing machine 1.

[0076] The ROM 52 stores programs for executing various processes such as a sewing process described later. The RAM 53 temporarily stores various information generated when executing various processes. The storage device 54 is non-volatile and stores the perfect stitch area and the hitch stitch area (see FIG. 14) when the movable member 32 is in the first position.

[0077] The drive circuits 61-66, the encoders 71A-73A, and the input unit 8A are connected to the I / O 55. The drive circuit 61 is connected to the main motor 71 and drives the main motor 71 based on a control command from the CPU 51. The drive circuit 62 is connected to the X motor 72 and drives the X motor 72 based on a control command from the CPU 51. The drive circuit 63 is connected to the Y motor 73 and drives the Y motor 73 based on a control command from the CPU 51. The drive circuit 64 is connected to the linear cylinder 34 and drives the linear cylinder 34 based on a control command from the CPU 51. The drive circuit 65 is connected to the air cylinders 4C and 4D and drives the air cylinders 4C and 4D based on a control command from the CPU 51. The drive circuit 66 is connected to the display unit 8B and displays various information on the display unit 8B based on a control command from the CPU 51.

[0078] The encoder 71A detects the rotation direction, rotation position, and rotation speed of the output shaft of the main motor 71, and outputs the detection result to the I / O 55. The detection result of the encoder 71A indicates the rotation direction, rotation position, and rotation speed of the upper shaft 17 and the lower shaft 22 driven by the main motor 71. The encoder 72A detects the rotation direction, rotation position, and rotation speed of the output shaft of the X motor 72, and outputs the detection result to the I / O 55. The detection result of the encoder 72A indicates the moving direction, left-right position, and moving speed of the needle bar 11 and the shuttle 23. The encoder 73A detects the rotation direction, rotation position, and rotation speed of the output shaft of the Y motor 73, and outputs the detection result to the I / O 55. The detection result of the encoder 73A indicates the moving direction, front-rear position, and moving speed of the holding mechanism 4A. The input unit 8A accepts the operation of the operator and outputs various instructions to the I / O 55.

[0079] <Sewing direction> A sewing pattern of the sewing machine 1 will be described with reference to FIG. 17. The sewing machine 1 sews the sewing object 99 based on the sewing pattern. A plurality of sewing patterns are stored in the memory device 54. For example, the sewing pattern shown in FIG. 17 includes coordinate information of a plurality of needle drop points P1 to P4. Needle drop point P1 is a position sewn by sewing the first stitch. Needle drop point P2 is a position sewn by sewing the second stitch. Needle drop point P3 is a position sewn by sewing the third stitch. Needle drop point P4 is a position sewn by sewing the fourth stitch.

[0080] The coordinate information of needle points P1 to P4 is stored as a combination of the left-right and front-rear positions of the needle bar 11. For example, when moving from needle point P1 to needle point P2, the CPU 51 calculates the direction of travel from the coordinate information of needle points P1 and P2. The perfect stitch area and hitch stitch area (see FIG. 14) when the movable member 32 is in the first position are stored in the memory device 54. When the movable member 32 is in the first position and the calculated direction of travel is included in the hitch stitch area, the CPU 51 moves the movable member 32 to the second position by the linear cylinder 34.

[0081] <Sewing process> The sewing process executed by the CPU 51 of the control unit 50 will be described with reference to Fig. 18. When an instruction to execute the sewing process is input by the operator via the input unit 8A, the CPU 51 starts the sewing process by executing a program called from the ROM 52. The instruction to execute the sewing process includes information that designates one of the sewing patterns stored in the storage device 54. When the sewing process starts, the movable member 32 is in the second position (see Figs. 11 and 12). The sewing workpiece 99 is held by the holding mechanism 4A.

[0082] When the sewing process is started, the CPU 51 moves the movable member 32, which is in the second position, forward by the linear cylinder 34 to the first position (see Figs. 9 and 10) (S1). This increases the size of the gap S. The contact portion 38 moves forward away from the lower thread R.

[0083] The CPU 51 sets the value of the variable N, which indicates the number of stitches, to 1 (S2). The CPU 51 acquires a sewing pattern specified by an instruction to execute a sewing process from the storage device 54 (S3). The CPU 51 moves the needle bar 11 and the shuttle 23 to the coordinates of the first stitch based on the sewing pattern acquired in S3 (S4). The head 6 and the shuttle mechanism 20 are moved in the left-right direction relative to the sewing workpiece 99 by driving the X motor 72, and the sewing workpiece 99 placed on the holding mechanism 4A is moved in the front-rear direction relative to the head 6 and the shuttle mechanism 20 by driving the Y motor 73.

[0084] The CPU 51 starts sewing by driving the main motor 71 to rotate the upper shaft 17 and the lower shaft 22 (S5). The needle bar 11 moves back and forth in the vertical direction, and the outer hook 24 rotates in the forward direction. The needle point 24C captures the loop of the upper thread and entangles it with the lower thread R, thereby forming a stitch on the sewing workpiece 99.

[0085] The CPU 51 determines whether or not a stitch has been formed on the sewing workpiece 99 (S6). The CPU 51 makes the determination in S6 based on the detection result of the encoder 71A. When the CPU 51 determines that a stitch has not been formed (S6: NO), the process returns to S6.

[0086] When the CPU 51 determines that the stitches have been formed (S6: YES), it determines whether sewing has been completed at all needle points included in the sewing pattern (S7).When the CPU 51 determines that sewing has not been completed (S7: NO), it executes a stopper process (S8).

[0087] The stopper process executed in S8 of the sewing process (see FIG. 18) will be described with reference to Fig. 19. The stopper process is a process for moving the movable member 32 to either the first position or the second position.

[0088] When the stopper process is started, the CPU 51 judges whether the value of N+1 is equal to or less than a predetermined value M (S11). If the value of N+1 is equal to or less than the predetermined value M (S11: YES), the CPU 51 determines that sewing of the N+1st stitch is the start of sewing, and returns the process to the sewing process. The movable member 32 arranged at the first position in S1 (see FIG. 18) does not move and remains at the first position.

[0089] If the value of N+1 is greater than the predetermined value M (S11: NO), the CPU 51 determines that the sewing of the N+1th stitch is not the start of sewing, and acquires the coordinates of the N+1th stitch from the sewing pattern acquired in S3 (see FIG. 18) (S12). The CPU 51 calculates the direction of travel toward the N+1th stitch based on the coordinates of the Nth stitch and the coordinates of the N+1th stitch (S13).

[0090] The CPU 51 judges whether the moving direction calculated in S13 is within the hitch stitch area at the first position (S14). If the moving direction is within the hitch stitch area at the first position (S14: YES), the CPU 51 judges whether the position of the movable member 32 is at the first position (S15). If the position of the movable member 32 is at the first position, there is a possibility that a hitch stitch will be formed if the N+1th stitch is sewn as it is. If the CPU 51 judges that the position of the movable member 32 is at the first position (S15: YES), the CPU 51 moves the movable member 32 at the first position backward by the linear cylinder 34 to the second position (S16), and returns the process to the sewing process. This reduces the size of the gap S. The process of S16 is executed while the sewing needle 11A is positioned above the needle hole 33A. If the CPU 51 judges that the movable member 32 is at the second position (S15: NO), the process returns to the sewing process.

[0091] When the moving direction is not within the hitch stitch area at the first position (S14: NO), the CPU 51 judges whether the position of the movable member 32 is at the first position (S17). When the position of the movable member 32 is at the first position, a perfect stitch is formed by sewing the N+1th stitch as it is. When the CPU 51 judges that the position of the movable member 32 is at the first position (S17: YES), the CPU 51 returns the process to the sewing process. When the CPU 51 judges that the movable member 32 is at the second position (S17: NO), the CPU 51 moves the movable member 32 at the second position forward by the linear cylinder 34 to the first position (S18), and returns the process to the sewing process. The process of S18 is executed while the sewing needle 11A is positioned above the needle hole 33A.

[0092] 18, after executing the stopper process (S8), the CPU 51 adds 1 to the value of the variable N (S9). Based on the sewing pattern acquired in S3, the CPU 51 moves the needle bar 11 and the shuttle 23 to the coordinates of the Nth stitch (S10). In the process of S10, similar to the process of S4, the head 6, the shuttle mechanism 20, and the workpiece 99 move relatively to each other in the left-right and front-rear directions by driving the X motor 72 and the Y motor 73. The CPU 51 repeats the processes of S6 to S10 until sewing is completed.

[0093] When the CPU 51 determines that sewing is completed at all needle points included in the sewing pattern (S7: YES), it stops driving the main motor 71, the X motor 72, and the Y motor 73 to stop sewing (S21). The CPU 51 moves the movable member 32 to the second position by the linear cylinder 34 (S22). The CPU 51 ends the sewing process.

[0094] When sewing is not being performed, when an operator rotates the rotary knob 18, the upper shaft 17 connected to the rotary knob 18 and the lower shaft 22 to which power is transmitted via the synchronization mechanism 9 also rotate. The rotation of the lower shaft 22 causes the outer hook 24 to rotate about an axis extending in the vertical direction. The rotation of the inner hook 25 is restricted by the abutment portions 37, 38. When the inner hook 25 rotates forward, the shuttle stopper portion 26 abuts against the abutment portion 37, and the forward rotation of the inner hook 25 is restricted. When the inner hook 25 rotates reversely, the shuttle stopper portion 26 abuts against the abutment portion 38, and the reverse rotation of the inner hook 25 is restricted.

[0095] <Actions and Effects of the Present Embodiment> As described above, the shuttle mechanism 20 includes the housing 20A, the outer shuttle 24, the inner shuttle 25, and the stopper 30. The stopper 30 includes the fixed member 31 including the contact portion 37, and the movable member 32 including the contact portion 38. The contact portions 37 and 38 face each other in the front-rear direction. The shuttle stopper portion 26 extending from the base portion 25A of the inner shuttle 25 is inserted into the gap S formed between the contact portions 37 and 38. The contact portion 37 restricts the forward rotation of the inner shuttle 25 by contacting the shuttle stopper portion 26. The contact portion 38 restricts the reverse rotation of the inner shuttle 25 by contacting the shuttle stopper portion 26. The fixed member 31 is fixed to the groove 20E of the housing 20A. The movable member 32 is movable in the front-rear direction. This allows the sewing machine 1 to change the size of the gap S. By changing the size of the gap S, the sewing machine 1 can prevent the upper thread from getting caught on the contact portion 38 and sufficiently regulate the rotation of the inner hook 25.

[0096] In the sewing machine 1, the movable member 32 is connected to the linear cylinder 34. The CPU 51 of the control unit 50 moves the movable member 32 in the front-rear direction by the linear cylinder 34. This allows the sewing machine 1 to move the movable member 32 in the front-rear direction more easily than when an operator manually moves the movable member 32 in the front-rear direction.

[0097] In the sewing machine 1, of the fixed member 31 and the movable member 32, the linear cylinder 34 is connected to the movable member 32. When the sewing machine 1 sews, the outer hook 24 rotates forward, and the inner hook 25 housed in the outer hook 24 also tends to rotate forward. When the inner hook 25 rotates forward, it tends to come into contact with the abutment portion 37 of the abutment portion 37 of the fixed member 31 and the abutment portion 38 of the movable member 32. In the sewing machine 1, the movable member 32 having the abutment portion 38 is moved by the linear cylinder 34, so that the rotation of the inner hook 25 can be effectively restricted when the sewing machine 1 sews.

[0098] In the sewing machine 1, the movable member 32 is moved by driving the linear cylinder 34. In this case, the sewing machine 1 can change the size of the gap S with a simple structure.

[0099] Before sewing is started by the sewing process, the movable member 32 is in the second position. When starting sewing by the sewing process, the CPU 51 moves the movable member 32, which is in the second position, forward by the linear cylinder 34 to place it in the first position (S1). The size of the gap S becomes larger. When the sewing machine 1 sews, the lower thread R slips under the extension portion 32J (see FIG. 13), and the loop of the upper thread may get caught on the abutting portion 38, causing the upper thread to untwist. When starting sewing, the sewing machine 1 moves the movable member 32 to increase the size of the gap S. This prevents the loop of the upper thread from getting caught on the abutting portion 38, and the sewing machine 1 can prevent the upper thread from untwisting.

[0100] When sewing by the sewing process is completed, the CPU 51 places the movable member 32 at the second position by the linear cylinder 34 (S22). When sewing is not being performed, if the operator rotates the rotary knob 18, the outer hook 24 rotates about an axis extending in the vertical direction. The rotation of the inner hook 25 is restricted by the abutment portions 37, 38. The size of the gap S is smaller when the movable member 32 is in the second position than when the movable member 32 is in the first position. Therefore, the sewing machine 1 can effectively restrict the rotation of the inner hook 25 when sewing is not being performed.

[0101] The CPU 51 calculates the moving direction from the Nth needle position to the N+1th needle position (S13). The CPU 51 judges whether the calculated moving direction is within the hitch stitch area at the first position (S14). If the moving direction is within the hitch stitch area at the first position, the CPU 51 moves the movable member 32 at the first position backward by the linear cylinder 34 and places it at the second position. The size of the gap S becomes smaller. In this case, the lower thread R is pushed out to the abutting portion 38, and the path toward the needle hole 33A is changed. As a result, the moving direction is switched from within the hitch stitch area (see FIG. 14) when the movable member 32 is at the first position to within the perfect stitch area (see FIG. 15) when the movable member 32 is at the second position. As a result, the sewing machine 1 can form a perfect stitch and suppress the formation of a hitch stitch.

[0102] The CPU 51 judges whether the value of N+1 is equal to or greater than a predetermined value M (S11). When the value of N+1 is equal to or less than the predetermined value M, the CPU 51 determines that the sewing of the N+1th stitch is the start of sewing and does not move the movable member 32 to the second position. At the start of sewing, the tension of the upper thread is small, so the lower thread R may slip under the extending portion 32J. At this time, the loop of the upper thread may get caught on the contact portion 38, and the upper thread may be untwisted. When the number of stitches is equal to or less than a predetermined number, the sewing machine 1 determines that the sewing is the start of sewing and does not displace the movable member 32 from the first position to the second position. This makes it difficult for the upper thread to get caught on the second contact portion at the start of sewing, and the sewing machine 1 can suppress the formation of a hitch stitch while suppressing the untwisting of the upper thread at the start of sewing.

[0103] The lower ends of the abutment parts 37, 38 are located above the sword tip 24C. The lower end of the abutment part 38 is located above the lower end of the abutment part 37. When the sewing machine 1 sews, a loop of the upper thread may get caught on the abutment part 38, causing the upper thread to untwist. Because the lower end of the abutment part 38 is located above the lower end of the abutment part 37, the sewing machine 1 can prevent the loop of the upper thread from getting caught on the abutment part 38 and causing the upper thread to untwist.

[0104] <Modification> The present invention can be modified in various ways from the above-described embodiment. The various modified examples described below can be combined with each other as long as no contradiction occurs. The type of sewing machine 1 is not limited to a double-column sewing machine, and may be various industrial sewing machines, household sewing machines, etc. as appropriate.

[0105] In the above embodiment, the fixed member 31 having the abutment portion 37 is fixed to the housing 20A, and the movable member 32 having the abutment portion 38 is movable in the front-rear direction. In contrast, the fixed member 31 may be movable in the front-rear direction, and the movable member 32 may be fixed to the housing 20A. Both the fixed member 31 and the movable member 32 may be movable in the front-rear direction.

[0106] In the above embodiment, the movable member 32 moves in the front-rear direction guided by the shoulder screws 42A, 42B. In contrast, in the sewing machine 1, it is sufficient if the size of the gap S can be changed by moving the movable member 32 along the front-rear direction, and for example, the movable member 32 may move in an arc extending in the front-rear direction. For example, the movable member 32 may reciprocate along an imaginary line extending to the left front and right rear.

[0107] The stopper 30 does not need to have the linear cylinder 34. In this case, the size of the gap S is changed by an operator moving the movable member 32 that is provided so as to be movable in the front-rear direction. The CPU 51 of the control unit 50 does not need to control the driving of the linear cylinder 34. In this case, the driving of the linear cylinder 34 may be controlled by the operator pressing or releasing the pressure on a push button.

[0108] In the above embodiment, the linear cylinder 34 is connected to the movable member 32, but is not limited to this. The linear cylinder 34 may be connected to the fixed member 31 instead of the movable member 32 and be movable, or conversely, the movable member 32 may be fixed to the housing 20A. The linear cylinder 34 may be connected to the movable member 32, and a linear cylinder different from the linear cylinder 34 may be connected to the fixed member 31.

[0109] In the above embodiment, the movable member 32 is moved in the front-rear direction by the linear cylinder 34, which is an air cylinder. In contrast, the linear cylinder 34 may be, for example, a hydraulic cylinder, a solenoid cylinder, a ball screw, or the like. The linear cylinder 34 may move the rod 34B in a direction other than the front-rear direction. For example, when moving the rod 34B in the left-right direction, the left-right power of the linear cylinder 34 may be converted into power for linear movement in the front-rear direction by a link mechanism or the like. The movable member 32 may be moved by driving a rotary actuator such as a servo motor instead of the linear cylinder 34. In this case, the power of the rotational movement by the rotary actuator may be converted into power for linear movement in the front-rear direction by a link mechanism, a rack-and-pinion mechanism, a timing belt, or the like.

[0110] The sewing process may be modified as appropriate. In the sewing process, the process of S1 may be omitted. In this case, when sewing starts, the movable member 32 is in the second position. In the sewing process, the process of S22 may be omitted. In this case, after the sewing process ends, the movable member 32 is in the position where it was located when it was last sewn.

[0111] In the sewing process, the process of S8 may be omitted. In this case, the movable member 32 does not move in the front-rear direction according to the sewing progress direction while the sewing machine 1 is sewing. In the stopper process, the process of S11 may be omitted. In this case, the movable member 32 moves in the front-rear direction according to the sewing progress direction from the first needle to the second needle.

[0112] In the above embodiment, the moving direction from the position of the Nth needle to the position of the (N+1)th needle is calculated based on the sewing pattern stored in memory device 54. However, CPU 51 may determine the moving direction using a sensor or the like that detects the moving direction of needle bar 11. The sensor that detects the moving direction is, for example, encoders 72A and 73A.

[0113] In the above embodiment, when the movable member 32 is in the first position, the movable member 32 is switched to the second position based on whether the traveling direction is within the hitch stitch area at the first position. In contrast, when the movable member 32 is in the second position, the movable member 32 may be switched to the first position based on whether the traveling direction is within the hitch stitch area at the second position.

[0114] In the above embodiment, the movable member 32 is switched to avoid hitch stitches in all sewing directions, but the present invention is not limited to this. For example, even if the movable member 32 is switched and a direction in which a hitch stitch area remains, the sewing data can be sufficiently utilized if the sewing data does not include sewing in the direction in which the remaining hitch stitch area is located or if the sewing data is short. Even if the hitch stitch area is only reduced by changing the position of the movable member 32, the sewing data can be effectively utilized to maintain sewing quality.

[0115] In the above embodiment, the sewing machine 1 switches the movable member 32 between the first position and the second position using the linear cylinder 34. In contrast, the sewing machine 1 may place the movable member 32 at one or more positions different from the first position and the second position. In the above embodiment, the movable member 32 is in the second position when the sewing machine 1 is not sewing and when the moving direction during sewing is within the hitch stitch area at the first position. In contrast, the movable member 32 may be placed at different positions when the sewing machine 1 is not sewing and when the moving direction during sewing is within the hitch stitch area at the first position.

[0116] The position of the movable member 32 may be changed to the first position or the second position depending on sewing conditions such as the type of the workpiece 99 and the type of thread. In this case, the control unit 50 of the sewing machine 1 may read the sewing conditions and automatically set the appropriate first and second positions of the movable member 32. Also, the first and second positions of the movable member 32 may be set and changed appropriately by an operator via the operation unit 8 or the like.

[0117] The lower end of the contact portion 38 does not have to be higher than the lower end of the contact portion 37. For example, the lower end of the contact portion 38 may be lower than the lower end of the contact portion 37.

[0118] Other modified examples will be described. The configuration of the shuttle mechanism 20 may be appropriately modified. The shuttle mechanism 20 may not have the fixed member 36. In this case, the shoulder screw 42A may be screwed into the housing 20A. A protrusion protruding upward from the bottom of the grooves 20D and 20E may be formed, and the protrusion may guide the movement of the movable member 32 in the front-rear direction. In this case, the shuttle mechanism 20 may not have the shoulder screws 42A and 42B. The inner shuttle 25 may not have the pressing portion 25E. The pinhole member 33 may be located above the movable member 32. The linear cylinder 34 may be connected to the movable member 32 without the connecting member 35.

[0119] The contact portions 37 and 38 are not limited to flat surfaces, and may be curved, uneven, inclined, or have projections, etc., as long as they can restrict the forward or reverse rotation of the inner shuttle 25 by contacting the shuttle stopper portion 26.

[0120] The control unit 50 is not limited to being provided in the sewing machine 1, but may be provided separately from the sewing machine 1. For example, the control unit 50 may be a device (such as a PC or a dedicated machine) connected to the sewing machine 1. Instead of the CPU 51, for example, a microcomputer, an ASIC (Application Specific Integrated Circuits), an FPGA (Field Programmable Gate Array), or the like may be used. The sewing process may be distributed or may be processed by a combination of the CPU 51 and the ASIC.

[0121] The non-transient storage medium such as the ROM 52 and the storage device 54 may be a storage medium capable of retaining information regardless of the period for which the information is stored. The non-transient storage medium may not include a temporary storage medium (e.g., a transmitted signal). For example, various programs, sewing patterns, etc. may be downloaded (i.e., transmitted as a transmission signal) from a server connected to a network (not shown) and stored in the ROM 52 or the storage device 54. In this case, the programs may be stored in a non-transient storage medium such as an HDD provided in the server.

[0122] <Other> The left-right direction is an example of the "first direction" of the present invention. The fixed member 31 is an example of the "first member" of the present invention. The movable member 32 is an example of the "second member" of the present invention. The contact portion 37 is an example of the "first contact portion" of the present invention. The contact portion 38 is an example of the "second contact portion" of the present invention. The front-rear direction is an example of the "second direction" of the present invention. The linear cylinder 34 is an example of the "drive portion" of the present invention. The processes of S1, S16, S18, and S22 executed by the CPU 51 are an example of the "control means" of the present invention. The second position is an example of the "initial position" and "second sewing position" of the present invention. The first position is an example of the "first sewing position" of the present invention. The process of S13 is an example of the "determination means" of the present invention. The hitch stitch area at the first position is an example of the "predetermined range" of the present invention. The process of S14 is an example of the "determination means" of the present invention. [Explanation of symbols]

[0123] 1. Sewing machine 20. Kettle mechanism 24 Outer pot 25 Medium Kettle 26 Hook stopper 30 Stopper 31 Fixing member 32 Movable parts 34 Linear cylinder 37, 38 Contact part 50 Control section 51 CPU S gap

Claims

1. It is equipped with a hook mechanism that captures the upper thread passing through the sewing needle and entangles it with the lower thread, The shuttle mechanism includes: an outer hook including a blade tip capable of capturing the upper thread and rotatable about an axis extending in a vertical direction; an inner hook that houses the lower thread and is rotatable around the axis relative to the outer hook inside the outer hook; a hook stopper portion connected to an outer periphery of the inner hook, rotatable about the axis together with the inner hook, and extending in a first direction among radial directions centered on the axis; a stopper having a first member and a second member; the first member has a first contact portion that can contact the shuttle stopper portion that rotates in a forward direction among the rotations around the axis, the second member has a second contact portion capable of contacting the shuttle stopper portion rotating in a reverse direction opposite to the forward rotation, The first contact portion and the second contact portion face each other in a second direction that intersects with the first direction and is horizontal, and the size of a gap formed between the first contact portion and the second contact portion can be changed by moving at least one of the first member and the second member in the second direction. A sewing machine characterized by:

2. a drive unit connected to at least one of the first member and the second member and configured to move the at least one of the first member and the second member in the second direction; and a control means for controlling the movement of the at least one of the hook mechanisms in the second direction by the drive unit when sewing is performed using the hook mechanism.

2. The sewing machine according to claim 1 .

3. The sewing machine according to claim 2 , wherein the drive portion is connected to the second member.

4. 3. The sewing machine according to claim 2, wherein the drive unit is a linear cylinder.

5. The control means, when starting the sewing, causes the drive unit to move the second member, which is disposed at an initial position, in a direction in which the gap becomes larger among the second directions, to place the second member at a first sewing position.

4. The sewing machine according to claim 3,

6. The control means, when completing the sewing, moves the second member disposed at the first sewing position in a direction in which the gap becomes smaller among the second directions by the drive unit, thereby disposing the second member at the initial position.

6. The sewing machine according to claim 5,

7. a determining means for determining a direction of movement from a position of an Nth needle (N is a natural number) to a position of an N+1th needle in the sewing workpiece; a determination means for determining whether the traveling direction determined by the determination means is within a predetermined range, The control means When the determining means determines that the moving direction is within the predetermined range, when starting sewing of the N+1 stitch, the second member disposed at the first sewing position is moved in the second direction to be disposed at a second sewing position different from the first sewing position.

4. The sewing machine according to claim 3,

8. the second sewing position is a position of the second member that is moved by the drive unit from the second member disposed at the first sewing position in a direction in which the gap becomes smaller in the second direction, The control means prevents the second member disposed at the first sewing position from being disposed at the second sewing position when the value of N+1 is equal to or smaller than a predetermined value M (M is a natural number equal to or greater than 2).

8. The sewing machine according to claim 7,

9. A lower end of the first contact portion and a lower end of the second contact portion are located above the tip, 2. The sewing machine according to claim 1, wherein a lower end of the second contact portion is located higher than a lower end of the first contact portion.

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