JP2013226246A - Sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sewing machine capable of adjusting the lenth of a needle thread end remaining at a sewing needle side.SOLUTION: A thread take-up device 30 which is arranged in an arm part 4 includes a fixed side arm, a movable side arm and a thread take-up motor. The other end 32b of the movable arm is exposed forward from the arm part 4. The other end 32b is in a first state where it is located on a needle thread feeding path 90 of a needle thread 6. The movable side arm becomes in a second state where the other end 32b moves rightward along a groove part 35 formed at the arm part 4 by the drive of the thread take-up motor, and the needle thread 6 is displaced to the outside of the needle thread feeding path 90 rightward. The sewing machine displaces and draws out the needle thread 6 on the needle thread feeding path 90 to the outside of the needle thread feeding path 90, so that it can adjust the amount of the needle thread 6 on the needle thread feeding path 90.

Description

  The present invention relates to a sewing machine in which a tension applying device is arranged in an upper thread supply path of an upper thread from a thread supply source to a sewing needle via a balance.

  Conventionally, an assertion force applying device for applying a first tension to an upper thread and a second tension smaller than the first tension in the upper thread supply path from the thread supply source to the sewing needle via the balance. There is a sewing machine in which an auxiliary tension applying device is arranged (see, for example, Patent Document 1). The sewing machine applies a first tension to the upper thread by the asserting force applying device at the time of sewing, and releases the application of the first tension to the upper thread by the asserting force applying device at the time of thread trimming after sewing by the sub tension applying device. Only the second tension is applied. The sewing machine can secure the amount of the upper thread drawn from the thread supply source at the time of thread trimming by the sub tension applying device.

Japanese Patent Laid-Open No. 11-244565

  In order to prevent the upper thread from coming off from the sewing needle after thread trimming, it is necessary to ensure a long upper thread end length remaining on the sewing needle side at the time of thread trimming. However, if the length of the upper thread end remaining on the sewing needle side is long, the so-called bird's nest is generated at the back side of the sewing object at the start of the next sewing. The sewing machine of Patent Document 1 has a problem that the length of the upper thread end remaining on the sewing needle side cannot be adjusted.

  An object of the present invention is to provide a sewing machine that can adjust the length of the upper thread end remaining on the sewing needle side.

  In order to solve the above-described problems, the sewing machine according to the present invention includes a sewing needle that passes through an upper thread and moves up and down by rotation of the main shaft, a balance that moves up and down by rotation of the main shaft, and the upper thread that is supplied from a thread supply source. An assertion force applying device that is provided in an upper thread supply path that reaches the sewing needle via the balance and the upper thread supply path, and that applies a first tension to the upper thread between the thread supply source and the balance. A subtension applying device that is provided in the upper yarn supply path and applies a second tension smaller than the first tension to the upper yarn between the yarn supply source and the asserting force applying device, and the asserting force A sewing machine comprising: a tension release mechanism that releases the application of the first tension to the upper thread by the application device; provided between the assertion force application device and the sub-tension application device; Front with the first tension applied to the yarn released Characterized in that the upper thread in the upper thread supply path comprising a thread take-up device for displacing out the upper yarn supply path.

  The sewing machine according to the first invention of the present application adjusts the amount of the upper thread on the upper thread supply path because the upper thread on the upper thread supply path from the thread supply source to the sewing needle is displaced out of the upper thread supply path. Can do. Therefore, the sewing machine can adjust the length of the end portion of the upper thread remaining on the sewing needle side, and can prevent the upper thread from being fixed on the back surface of the sewing object at the start of sewing and generating a bird's nest.

  A sewing machine according to a second aspect of the present invention is the sewing machine according to claim 1, wherein the thread take-up device includes an upper thread holding part that holds the upper thread that is conveyed through the upper thread supply path, and the upper thread holding part that is used as the upper thread. And a drive unit that moves between a first state located in the supply path and a second state located outside the upper thread supply path.

  The sewing machine according to the second aspect of the present invention is configured to remove the upper thread on the upper thread supply path from the thread supply source to the sewing needle with a simple configuration by simply moving the upper thread holding portion between the first state and the second state. It can be pulled out of the supply path.

  A sewing machine according to a third aspect of the present invention is the sewing machine according to claim 1 or 2, wherein a needle plate having a needle hole through which a lower end of the sewing needle passes is provided below the needle plate and interlocked with the vertical movement of the sewing needle. And a hook mechanism that rotates below the needle plate and above the hook mechanism to cut the upper thread and lower thread, and after the upper thread and lower thread are cut by the thread cutting mechanism. A sewing machine further comprising: a thread take-up control means for displacing the upper thread out of the upper thread supply path by the yarn take-up device.

  The sewing machine according to the third aspect of the invention drives the thread take-up device after the upper thread and lower thread are cut by the thread trimming mechanism. Therefore, the end of the upper thread remaining on the sewing needle side without pulling the upper thread from the thread supply source side after thread trimming. The length of can be adjusted.

  The sewing machine of the present invention can adjust the length of the upper thread end remaining on the sewing needle side.

It is a perspective view of a sewing machine. It is an expansion perspective view of a shuttle mechanism and a thread trimming mechanism. It is an expansion perspective view of the principal part of a sewing machine. It is a perspective view of a thread take-up device. It is a front view which shows operation | movement of a yarn taking device. It is a perspective view of a thread loosening mechanism. It is a figure which shows the electrical constitution of a sewing machine. It is a flowchart of a thread take-up process. (A) is a side view of a thread take-up device according to a modification, and (B) is a perspective view of the thread take-up device according to a modification. It is a front view which shows operation | movement of the thread take-up apparatus of a modification.

  A sewing machine according to an embodiment of the present invention will be described with reference to the drawings. The upper side, the lower side, the left diagonal lower side, the right diagonal upper side, the right diagonal lower side, and the left diagonal upper side in FIG. 1 are the upper side, lower side, left side, right side, front side, and rear side of the sewing machine 1, respectively.

  As shown in FIG. 1, the sewing machine 1 includes a bed portion 2, a pedestal portion 3, and an arm portion 4. The sewing machine 1 is mounted from above so that the upper surface of the bed portion 2 is flush with the upper surface (work surface) of the work table 100. The pedestal 3 is erected upward from the right end of the bed 2. The arm part 4 extends to the left from the upper end of the pillar 3 so as to face the upper surface of the bed part 2. The arm part 4 is provided with an operation part 5 at the top. A thread supply source 110 such as a thread spool is provided behind the arm portion 4. The arm portion 4 has a main shaft (not shown) that is rotated by a sewing machine motor 170 (see FIG. 7) disposed in the inside thereof so as to extend in the left-right direction. The sewing machine 1 includes a knee pad 14 that can be operated by an operator below the work table 100.

  As shown in FIG. 2, the sewing machine 1 includes a shuttle mechanism 70 and a thread trimming mechanism 80 below the needle plate 11. The needle plate 11 includes a needle hole 11a through which the sewing needle 10 can be inserted. The shuttle mechanism 70 rotates by driving the sewing machine motor 170. The sword tip of the shuttle mechanism 70 catches the loop of the upper thread that is formed when the sewing needle 10 rises from the bottom dead center. The hook mechanism 70 spreads the loop of the upper thread captured by the sword tip. The sewing machine 1 forms a seam on the workpiece to be sewn by entwining the upper thread loop and the lower thread that are spread by the hook mechanism 70. Since the specific structure of the shuttle mechanism 70 is the same as the conventional structure, detailed description thereof is omitted.

  The thread trimming mechanism 80 is provided above the shuttle mechanism 70 and close to the needle hole 11a of the needle plate 11. The thread trimming mechanism 80 includes a lower moving blade 81 and an upper moving blade 82. The lower moving blade 81 and the upper moving blade 82 can rotate on the outer periphery of the shuttle mechanism 70. The lower moving blade 81 moves forward from the standby position behind the needle hole 11a. The upper moving blade 82 moves backward from the front standby position with respect to the needle hole 11a. The thread trimming mechanism 80 moves the lower moving blade 81 and the upper moving blade 82 by driving a thread trimming solenoid 131 (see FIG. 7). The thread trimming solenoid 131 is driven by an output of a thread trimming signal at the time of thread trimming. The lower moving blade 81 and the upper moving blade 82 move in directions close to each other, and the upper moving blade 82 overlaps the upper side of the lower moving blade 81. The lower moving blade 81 and the upper moving blade 82 cooperate to cut the upper thread and the lower thread.

  As shown in FIG. 3, the arm unit 4 includes an upper thread supply path 90 of the upper thread 6 that is supplied from a thread supply source 110 (see FIG. 1) on the left end side. The arm unit 4 includes, in order from the upstream side of the upper thread supply path 90, a sub tension device 20, a thread take-up device 30, a main tension device 40, a thread guide 7, a balance 8, a needle bar 9, and a sewing needle 10. In the arm portion 4, upper thread guide members 12 and 13 are disposed between the thread guide 7 and the balance 8 and between the balance 8 and the needle bar 9.

  The thread guide 7 guides the upper thread 6 that has passed through the main tension device 40 by turning it back toward the upper balance 8. The balance 8 pulls up the upper thread 6 by moving up and down. The balance 8 is interlocked with the vertical movement of the needle bar 9 and the sewing needle 10. The needle bar 9 reciprocates up and down by the rotation of the main shaft. The sewing needle 10 is attached to the lower end of the needle bar 9.

  The sub tension device 20 is provided at the upper end of the arm portion 4, and adjusts the tension applied to the upper thread 6 on the upstream side of the upper thread supply path 90. The secondary tension device 20 applies a second tension to the upper thread 6. The sub tension device 20 suppresses the unexpected feeding of the upper thread 6 from the thread supply source 110 during thread trimming. The subtone device 20 includes an operation dial 21, a tension applying spring 22, a pair of dish members 23, and upstream and downstream guide members 24 and 25.

  The operation dial 21 is a tension adjustment dial that can be operated manually by the operator. The tension applying spring 22 can adjust the urging force according to the operation position of the operation dial 21. The pair of plate members 23 applies tension to the upper thread 6 by urging from the tension applying spring 22. In the pair of plate members 23, the pressure between the opposed members is changed by adjusting the biasing force of the tension applying spring 22, and the tension applied to the upper thread 6 is changed. In the pair of plate members 23, the tension applied to the upper thread 6 increases as the biasing force from the tension applying spring 22 increases. The tension applied to the upper thread 6 is adjusted according to the thickness of the upper thread 6 and the like. The upstream and downstream guide members 24 and 25 guide the upper thread 6 between the pair of dish members 23.

  As shown in FIGS. 3 to 5, the thread take-up device 30 is disposed inside the arm portion 4. The yarn take-up device 30 includes a fixed side arm 31, a movable side arm 32, and a yarn take-up motor 36. The fixed side arm 31 is a plate member formed in an L shape in a side view and extends in the vertical direction (the horizontal direction in FIG. 4). The fixed side arm 31 is provided with a screw hole 31a for fixing to the arm portion 4 at one end. The other end 31 b of the fixed side arm 31 is bent at a substantially right angle forward (upward in FIG. 4) and exposed forward from the arm portion 4. The other end 31b is provided with a thread insertion hole 31c through which the upper thread 6 can be inserted. The thread insertion hole 31 c is located on the upper thread supply path 90 of the upper thread 6. The fixed side arm 31 has an output shaft 37 of a thread take-up motor 36 rotatably inserted on the same surface as the screw hole 31a.

  The movable arm 32 is a plate member formed in an L shape in a side view and extends in the vertical direction. One end of the movable arm 32 is in contact with the fixed arm 31. The other end 32 b of the movable arm 32 is bent forward at a substantially right angle and exposed forward from the arm portion 4. The other end 32b is provided with a thread insertion hole 32c through which the upper thread 6 can be inserted. The other end 32 b is located between the downstream guide portion 25 of the sub-tone device 20 and the other end 31 b of the fixed arm 31. The other end 32b is in a first state where the other end 32b is positioned on the upper thread supply path 90 of the upper thread 6 when the thread take-up motor 36 is not driven. The movable arm 32 is fixed to the output shaft 37 of the thread take-up motor 36.

  The thread take-up motor 36 is provided behind the fixed side arm 31 and the movable side arm 32 (downward in FIG. 4). The thread take-up motor 36 is a pulse motor. The thread take-up motor 36 is supported by a frame (not shown) of the arm portion 4. An output shaft 37 of the thread take-up motor 36 can rotate the movable arm 32.

  When the thread take-up motor 36 is driven, the movable arm 32 fixed to the output shaft 37 rotates about the output shaft 37 clockwise as viewed from the front (see FIG. 5). When the movable arm 32 rotates, the other end 32b moves to the right along the groove portion 35 (see FIG. 3) formed in the arm portion 4. The other end 32b of the movable arm 32 is a second state in which the upper thread 6 between the downstream guide portion 25 and the other end 31b is displaced out of the upper thread supply path 90 on the right side.

  As shown in FIG. 6, the main tension device 40 is provided below the secondary tension device 20, and adjusts the tension applied to the upper thread 6 on the downstream side of the upper thread supply path 90. The main tension device 40 applies a first tension larger than the second tension to the upper thread 6. The main tension device 40 includes an operation dial 41, a tension applying spring 42, a pair of plate members 43, a thread take-up spring 44, and a drive rod 45. The operation dial 41 is a tension adjustment dial that can be operated manually by the operator. The tension applying spring 42 can adjust the urging force according to the operation position of the operation dial 41. The pair of plate members 43 applies tension to the upper thread 6 by urging from the tension applying spring 42. In the pair of plate members 43, the opposing pressure is changed by the bias of the tension applying spring 42, and the tension applied to the upper thread 6 is changed. The thread take-up spring 44 hangs the upper thread 6 passed between the pair of plate members 43. The drive rod 45 extends in the front-rear direction, and moves forward by driving a thread loosening mechanism 120 provided in the arm portion 4 to release the bias of the tension applying spring 42 against the pair of plate members 43. In addition, since the specific structure and effect | action of the main tone apparatus 40 are well-known, detailed description is abbreviate | omitted.

  As shown in FIG. 6, the arm portion 4 includes a thread loosening mechanism 120 inside. The thread loosening mechanism 120 is driven by an operation of the thread trimming solenoid 131 (see FIG. 7) or the knee pad 14 by an operator. The thread loosening mechanism 120 includes a thread loosening plate 121, a thread loosening wire 122, and a drive rod 123. The thread loosening plate 121 is substantially L-shaped when viewed from the front, and has an upper end connected to one end of the thread loosening wire 122 and a right end in contact with the rear end of the drive rod 123. The thread loosening plate 121 is rotatably supported by a support shaft (not shown) inside the arm portion 4. The thread loosening plate 121 moves the driving rod 123 forward and backward by rotating. The other end of the thread loosening wire 122 is connected to a thread trimming solenoid 131 (see FIG. 7), and the thread trimming solenoid 121 is rotated around the support shaft in the clockwise direction by driving the thread trimming solenoid 131. The front end of the drive rod 123 abuts on the drive rod 45 of the main tone device 40. As the thread loosening plate 121 rotates in the clockwise direction when viewed from the front, the drive rod 123 moves forward. The drive rod 123 pushes the drive rod 45 forward to release the bias of the tension applying spring 42 against the pair of plate members 43.

  The electrical configuration of the sewing machine 1 will be described with reference to FIG. The control device 160 is configured by a microcomputer including a CPU 161, a ROM 162, a RAM 163, and a nonvolatile memory 168. The CPU 161 controls the sewing machine 1 and executes various calculations and processes according to various programs stored in the ROM 162. The CPU 161 is electrically connected to the ROM 162, RAM 163, nonvolatile memory 168, and input / output interface (I / F) 164 via a bus.

  The ROM 162 stores in advance a control program for sewing control including drive control of various drive mechanisms. The RAM 163 temporarily stores various memories for storing the calculation results calculated by the CPU 161, pointers, counter values, and the like. The nonvolatile memory 168 stores data such as the driving amount of the thread take-up motor 36 set by the operator via the operation unit 5 and various values.

  The input / output I / F 164 is connected to the activation pedal 166 and the operation unit 5. The CPU 161 acquires a sewing start signal and a thread trimming signal from the activation pedal 166. The activation pedal 166 outputs various signals by the operator's stepping operation. The CPU 161 acquires an operation instruction from the operator from the operation unit 5. The input / output I / F 164 is connected to the drive circuits 172, 173, and 174. The drive circuit 172 drives the sewing machine motor 170 in accordance with a torque command signal input from the CPU 161. The sewing machine 1 includes an encoder 171 for detecting the rotation angle phase and the rotation speed of the sewing machine motor 170. The encoder 171 outputs the detection result to the input / output I / F 164. The drive circuit 173 drives the thread trimming solenoid 131 according to the thread trimming signal input from the CPU 161. The drive circuit 174 drives the thread take-up motor 36 in accordance with the thread take-up drive signal input from the CPU 161. The thread take-up motor 36 is a pulse motor, and the thread take-up drive signal is a pulse signal.

  With reference to FIG. 8, the thread removal process will be described. The thread take-up process starts when the operator inputs an instruction to end the sewing process by operating the activation pedal 166 during the sewing process.

  The CPU 161 determines whether a thread trimming signal has been received (S10). The thread trimming signal is a signal output from the activation pedal 166 when an operator inputs a thread trimming instruction by operating the activation pedal 166 during sewing processing. When the thread trimming signal is not received (S10: NO), the CPU 161 ends the process.

  When the thread trimming signal is received (S10: YES), the CPU 161 detects the rotation angle phase of the sewing machine motor 170 from the encoder 171 (S20).

  The CPU 161 determines whether it is time to cut the upper thread and lower thread by the thread trimming mechanism 80 (hereinafter simply referred to as “thread trimming timing”) (S30). The thread trimming timing is when the sewing needle 10 has moved to a predetermined height after the operator inputs a thread trimming instruction. The determination as to whether or not it is the thread trimming timing is made based on the detection result of the encoder 171. When it is not the thread trimming timing (S30: NO), the CPU 161 shifts the process to S40.

  When it is the thread trimming timing (S30: YES), the CPU 161 turns on the thread trimming solenoid 131 (S35). As described above, when the thread trimming solenoid 131 is turned on, the lower moving blade 81 and the upper moving blade 82 move in directions close to each other and cooperate to cut the upper thread and the lower thread. At the same time, the thread trimming solenoid 131 is turned on to drive the thread loosening mechanism 120 to release the bias of the tension applying spring 42 against the pair of plate members 43 of the main tension device 40. The upper tension 6 is not given the first tension by the main tension device 40. The CPU 161 returns the process to S20.

  The CPU 161 determines whether it is time to stop driving the sewing machine motor 170 after the upper thread and lower thread are cut (hereinafter, simply referred to as “sewing motor stop timing”) (S40). The sewing machine motor stop timing is a point in time when the sewing needle 10 moves to a stop height (slightly below the top dead center of the sewing needle 10) after cutting the upper thread and the lower thread. Judgment whether or not it is the timing of stopping the sewing motor is made based on the detection result of the encoder 171. When it is not the sewing machine motor stop timing (S40: NO), the CPU 161 returns the process to S20.

  When it is the sewing machine motor stop timing (S40: YES), the CPU 161 stops the driving of the sewing machine motor 170 (S50). That is, the sewing machine 1 stops driving the sewing machine motor 170 after cutting the upper thread and the lower thread. At this time, only the second tension from the secondary tension device 20 is applied to the upper thread 6.

  The CPU 161 drives the thread take-up motor 36 based on the drive amount stored in the nonvolatile memory 168 (S60). By driving the thread take-up motor 36, the upper thread 6 held by the other end 32 b of the movable arm 32 is changed from the first state located on the upper thread supply path 90 to the second state outside the upper thread supply path 90. Displace. Since only the second tension is applied to the upper thread 6, the upper thread 6 is not pulled out from the thread supply source 110 side but pulled from the sewing needle 10 side. That is, in the sewing machine 1, the length L1 of the upper thread 6 remaining on the sewing needle 10 after thread trimming changes to L2 (see FIG. 3). Thereafter, in a state where the first tension is applied by the main tension device 40, the movable side arm 32 is rotated again so that the other end 32 b returns to the first state on the upper thread supply path 90.

  As described above, the nonvolatile memory 168 stores a drive amount that is set in advance by the operator using the operation unit 5. The driving amount is represented by the number of pulses for driving the yarn take-up motor 36 or the rotation angle of the output shaft 37 of the yarn take-up motor 36. The sewing machine 1 can change the displacement amount (L1−L2) that is the difference between L1 and L2 by changing the drive amount. That is, the sewing machine 1 can change the length L2 of the upper thread 6 after the thread take-up motor 36 is driven. The CPU 161 ends the process after the yarn take-up motor 36 is driven.

  As described above, the sewing machine 1 according to the present embodiment includes the thread take-up device 30 inside the arm portion 4. In the yarn take-up device 30, the movable arm 32 is rotated by a yarn take-up motor 36. The movable arm 32 changes from the first state in which the other end 32b is positioned on the upper thread supply path 90 of the upper thread 6 to the second state in which the upper thread 6 is displaced out of the upper thread supply path 90 by rotation. The sewing machine 1 pulls out the upper thread 6 on the upper thread supply path 90 from the thread supply source 110 to the sewing needle 10 by displacing the upper thread 6 out of the upper thread supply path 90. Can be adjusted. Therefore, the sewing machine 1 can adjust the length of the end portion of the upper thread 6 remaining on the sewing needle 10 side, so that the upper thread 6 is fixed on the back surface of the sewing object at the start of sewing and a bird's nest is generated. Can be prevented. The sewing machine 1 can move the other end 32b of the movable arm 32 between the first state and the second state with a simple configuration in which the thread take-up motor 36 only rotates the movable arm 32.

  The sewing machine 1 drives the thread trimming solenoid 131 at the thread trimming timing and cuts the upper thread and the lower thread by the thread trimming mechanism 80. The sewing machine 1 stops driving the sewing machine motor 170 after thread trimming and drives the thread take-up motor 36. The sewing machine 1 drives the yarn take-up motor 36 in a state in which the yarn tensioning mechanism 120 has released the application of the first tension to the upper yarn 6 on the upper yarn supply path 90 by the main tension device 40 by the yarn trimming solenoid 131. Therefore, the sewing machine 1 can adjust the length of the end portion of the upper thread 6 remaining on the sewing needle 10 side without pulling out the upper thread 6 from the thread supply source 110 side after thread trimming.

  The main tone device 40 corresponds to the “asserting force imparting device” of the present invention. The sub-tone device 20 corresponds to the “sub-tension applying device” of the present invention. The thread loosening mechanism 120 corresponds to the “tension releasing mechanism” of the present invention. The drive rod 123 corresponds to the “drive member” of the present invention. The other end 32b corresponds to the “upper thread holding portion” of the present invention. The thread take-up motor 36 corresponds to the “drive unit” of the present invention. The CPU 161 that executes the process of S60 corresponds to the “thread removal control means” of the present invention.

  The present invention is not limited to the above embodiment, and various modifications can be made. For example, the yarn take-up device 30 is composed of two arms, that is, the fixed side arm 31 and the movable side arm 32, but may be composed of a plurality of fixed side arms and one movable side arm. The yarn take-up device does not have to be provided with the fixed side arm.

  With reference to FIGS. 9 and 10, a modification of the thread take-up device will be described. The thread take-up device 60 according to the modified example has a configuration having only one movable arm 61 without providing a fixed arm.

  As shown in FIG. 9, the yarn take-up device 60 includes a movable arm 61 and a yarn take-up solenoid 62 (drive unit). The movable arm 61 has one end 61 a connected to the plunger 63 of the thread take-up solenoid 62. The thread take-up solenoid 62 is fixed to the arm portion 4. The other end 61b of the movable arm 61 is bent at a substantially right angle to provide an insertion hole 61c. The other end 61b is arranged in the arm portion 4 so that the insertion hole 61c is oriented in the vertical direction. The other end 61b may be provided on the upstream side of the main tone device 40 and may be positioned between the downstream guide portion 25 of the sub tone device 20.

  As shown in FIG. 10, in the yarn take-up solenoid 62, the plunger 63 is normally retracted and the other end 61 b is positioned on the upper yarn supply path 90. When the thread take-up solenoid 62 is driven, the plunger 63 advances to the right and displaces the upper thread 6 between the main tension device 40 and the downstream guide portion 25 of the sub tension apparatus 20 to the outside of the upper thread supply path 90. Can do.

  The other end 61b of the modification corresponds to the “upper thread holding portion” of the present invention. The thread take-up solenoid 62 corresponds to the “drive unit” of the present invention.

  The drive unit may be driven by a solenoid, a cylinder or the like even when a fixed arm and a movable arm are provided. The thread take-up device may be provided outside the arm portion 4. The thread loosening mechanism 120 may be driven by a driving source (solenoid or the like) different from the thread trimming solenoid 131. In this case, the drive source may be driven in synchronism with the drive of the thread trimming solenoid 131.

DESCRIPTION OF SYMBOLS 1 Sewing machine 4 Arm part 6 Upper thread 8 Balance 10 Sewing needle 11 Needle plate 20 Sub tension device 30 Thread take-up device 32 Movable side arm 36 Thread take-up motor 40 Main tension device 50 Thread take-up device 60 Thread take-up device 61 Movable side arm 63 Thread take-up solenoid 70 Hook mechanism 80 Thread trimming mechanism 120 Thread loosening mechanism

Claims (3)

A sewing needle that passes through the upper thread and moves up and down by the rotation of the main shaft;
A balance that moves up and down by the rotation of the spindle;
An upper thread supply path through which the upper thread supplied from a thread supply source reaches the sewing needle via the balance;
An assertion force applying device that is provided in the upper thread supply path and applies a first tension to the upper thread between the thread supply source and the balance;
A subtension applying device that is provided in the upper yarn supply path and applies a second tension smaller than the first tension to the upper yarn between the yarn supply source and the assertive force applying device;
In a sewing machine comprising: a tension release mechanism that releases the application of the first tension to the upper thread by the assertion force applying device,
The upper thread in the upper thread supply path is provided between the assertion force applying apparatus and the sub-tension applying apparatus, and the tension release mechanism releases the application of the first tension to the upper thread. A sewing machine comprising a thread take-up device that displaces the upper thread supply path. The sewing machine according to claim 1, wherein
The thread take-up device is
An upper thread holding portion that holds the upper thread conveyed by the upper thread supply path;
A sewing machine comprising: a drive unit configured to move the upper thread holding unit between a first state positioned on the upper thread supply path and a second state positioned outside the upper thread supply path. In the sewing machine according to claim 1 or 2,
A needle plate having a needle hole through which the lower end of the sewing needle passes;
A hook mechanism provided below the needle plate and rotating in conjunction with the vertical movement of the sewing needle;
A thread trimming mechanism that is positioned below the needle plate and above the shuttle mechanism to cut the upper thread and the lower thread;
A sewing machine further comprising: a thread take-up control means for displacing the upper thread out of the upper thread supply path by the thread take-up device after the upper thread and the lower thread are cut by the thread cutting mechanism.

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