Threading holder of sewing machine

[0019] Refer below Figure 1 ~ Figure 12 The embodiment of the present invention is explained.

[0020] Such as figure 1 As shown, the electronic bar tacking reinforcement sewing machine 1 is set on the workbench 8. The electronic bar tacking sewing machine 1 is composed of a bottom plate 2, a pillar 5 extending upward from the rear end of the bottom 2, and an arm 6 extending forward from the upper end of the pillar 5. The arm 6 and the bottom The upper part of section 2 is opposite. The length of the bottom plate portion 2 and the arm portion 6 is relatively long in the front and rear direction, and the length in the left and right direction is relatively short.

[0021] An operation panel 9 is installed on the workbench 8. The operation panel 9 is equipped with a liquid crystal display 9a, a selection switch 9b for selecting the type of bar tacking reinforcement stitch and the pattern of the bar tacking reinforcement stitch, and setting whether to set the end of the upper thread 7 when forming the bar tacking reinforcement stitch 7a (reference Figure 5 ) Thread clamping mode switch 9c for clamping, setting switch 9d for setting sewing conditions such as sewing speed, and initial setting switch 9e (refer to Picture 10 ).

[0022] Inside the arm portion 6, a needle bar vertical movement mechanism and a thread take-up lever vertical movement mechanism (both not shown) are housed. The needle bar up and down movement mechanism can make the needle bar 10 (refer to figure 1 ) Move up and down, stitch 11 (refer to figure 1 ) Is mounted on the needle bar 10. The up and down movement mechanism of the thread take-up lever can make the thread take-up lever 72 (refer to figure 1 ) Move up and down, and the upper thread 7 is lifted by the thread take-up lever 72 ascending.

[0023] A driving force transmission mechanism (not shown) is housed in the inside of the pillar part 5 and the inside of the arm part 6. The driving force transmission mechanism transfers the sewing machine motor 67 (refer to Picture 10 The rotational force of) is transmitted to the needle bar up-and-down movement mechanism, the sewing machine motor 67 is mounted on the support 5, and the main shaft is housed in the arm 6. A presser foot drive mechanism (not shown) is housed in the inside of the pillar part 5 and the inside of the arm part 6. The presser foot drive mechanism transmits driving force to the cloth presser mechanism (not shown), and the cloth presser mechanism uses the driving force transmitted from the presser foot drive mechanism to make the presser foot 13 (see figure 1 ) Move up and down. The cloth pressing mechanism will press the motor 68 (refer to Picture 10 ) Is housed in the bottom plate 2 as a driving source.

[0024] Such as figure 1 As shown, the bottom plate portion 2 is composed of a bottom plate body portion 3 and a cylindrical bottom plate portion 4. The bottom plate main body portion 3 refers to a portion that supports the pillar portion 5 in the bottom plate portion 2, and the cylindrical bottom plate portion 4 refers to a portion extending forward from the bottom plate body portion 3. In the cylindrical bottom plate portion 4, the needle plate 12 is attached with a plurality of screws. The needle plate 12 can be taken out of the cylindrical bottom plate portion 4 by removing a plurality of screws. Such as Image 6 As shown, the needle plate 12 is formed with a circular needle hole 12a penetrating the needle plate 12 in the thickness direction.

[0025] A cloth feeding mechanism (not shown) is housed in the bottom plate 2. This feeding mechanism is driving the Y-axis drive motor 71 (refer to Picture 10 ) Is transmitted to the feed plate 14 (refer to figure 1 ) On the basis of operating the feed plate 14 directions figure 1 Moves in the front and rear direction (Y direction) and drives the X-axis drive motor 70 (refer to Picture 10 ) Based on the driving force transmitted to the feed plate 14, operating the feed plate 14 to figure 1 Move in the left and right direction (X direction) to process the cloth W (refer to image 3 ) Follow the movement of the feed plate 14 in the front-rear direction and the left-right direction and move in the front-rear direction and the left-right direction. A thread trimming mechanism (not shown) is installed inside the bottom plate 2. The thread cutting mechanism is used to cut the upper thread 7 and the lower thread, and it operates when the sewing process is finished.

[0026] A pedal 18 (refer to Picture 10 ), when the operator depresses the pedal 18 from the initial position to the cloth pressing position of the first stage, the motor 68 is pressed as the operator presses (refer to Picture 10 ) Is driven to move the presser foot 13 to the lower cloth press position, and press the processed cloth W on the upper surface of the needle plate 12. When the pedal 18 is depressed from the cloth press position of the first step to the sewing position of the second step, the sewing process is started. The pedal 18 is a member that overcomes the elastic force of the pedal spring (not shown) and is stepped on from the initial position to the cloth pressing position and the sewing position. The operator depresses the pedal 18 to the cloth pressing position or the sewing position. In the state, when the foot leaves the pedal 18, the pedal 18 uses the elastic force of the pedal spring to return to the initial position.

[0027] Such as figure 1 As shown, a vertical shuttle 15 is installed inside the bottom plate 2. The vertical shuttle 15 is arranged in a direction perpendicular to the front-rear direction of the rotating shaft, and has image 3 The shuttle bed 15a, the shuttle 15b, and the shuttle 15c are shown. The shuttle bed 15a is statically arranged in the bottom plate portion 2, and the shuttle 15b is rotatably housed in the shuttle bed 15a. The shuttle 15b has a tip 15d, and the bobbin case 17 is housed in the shuttle 15b. A bobbin (not shown) is housed in the bobbin case 17, and a bobbin thread is wound in the bobbin.

[0028] Such as figure 1 As shown, the lower shaft 16 is housed inside the bottom plate portion 2. The lower shaft 16 alternately repeats forward rotation and reverse rotation in conjunction with the main shaft. The amount of rotation of the lower shaft 16 is set within a range of 220 degrees to 230 degrees. This action is called swinging, and the driving force for swinging the lower shaft 16 is transmitted to the swing shuttle 15 b through the swing shuttle 15 c, and the swing shuttle 15 b swings in conjunction with the lower shaft 16 by the driving force transmitted from the lower shaft 16. That is, the tip 15d of the shuttle 15b catches the loop of the upper thread 7 on the lower side of the needle plate 12 following the forward rotation of the shuttle 15b. The shuttle tip 15d is a member that acts as a guide when the shuttle 15b enters and exits the loop of the upper thread. The shuttle 15b swings in conjunction with the up and down movement of the sewing needle 11 to form stitches.

[0029] Such as Figure 4 As shown, on the needle plate 12, two small screws 30a are used to fix the fixed knife 30. The fixed knife 30 has a blade portion and is arranged below the needle plate 12. On the needle plate 12, a movable knife 31 is rotatably attached with a pin 32 as the center. The movable knife 31 has a blade portion, and the thread trimming link 33 is rotatably connected to the movable knife 31 about a shaft 33a. The thread trimming link 33 passes through a thread trimming drive mechanism (not shown) and a thread trimming solenoid 69 (refer to Picture 10 ) Connection. When the thread trimming solenoid 69 is turned on, with the movement of the thread trimming link 33, the movable knife 31 rotates with the pin 32 as the center, and the upper thread 7 and the lower thread between the movable knife 31 and the fixed knife 30 The lines are cut at the same time.

[0030] Such as figure 1 As shown, the upper thread clamping mechanism 20 is housed inside the bottom plate portion 2. The upper thread clamping mechanism 20 is a member that clamps the thread end portion 7a of the upper thread 7 when the bar tacking reinforcement stitch is formed, and operates on the condition that the thread clamping mode switch 9c is turned on. Next, the upper thread clamping mechanism 20 will be described.

[0031] Such as Figure 4 As shown, the upper thread holding mechanism 20 has a first thread holding plate 21 corresponding to the first thread holding member and a second thread holding plate 22 corresponding to the second thread holding member. The first thread clamping plate 21 is rotatably mounted on the needle plate 12 with the vertical first pin 23 as the center, and is arranged on Figure 5 The underside of the needle plate 12 is shown. Such as Figure 4 As shown, the first pin 23 is arranged on the rear left side of the needle hole 12a of the needle plate 12, and the first thread clamping plate 21 has an L-shape having an arm portion 21a and an arm portion 21c. A first thread gripping portion 21b is formed at the front end portion of the arm portion 21a of the first thread gripping plate 21, and a stopper is formed in the longitudinal center portion of the arm portion 21c of the first thread gripping plate 21 部21d. The first thread clamping portion 21b is a portion directly related to the clamping operation of the upper thread 7, and is a portion protruding to the right from the arm portion 21a. The stopper portion 21d is a portion that restricts the rotation of the first thread clamping plate 21 while directly contacting the object, and is a portion that protrudes rearward from the arm portion 21c.

[0032] The second thread holding plate 22 is rotatably mounted on the needle plate 12 with the vertical second pin 24 as the center, and is arranged on Figure 5 The lower side of the needle plate 12 shown is arranged adjacent to the lower side of the first thread clamping plate 21. Such as Figure 4 As shown, the second thread clamping plate 22 has an L-shape having an arm portion 22a and an arm portion 22c, and the second pin 24 of the second thread clamping plate 22 is arranged on the first pin of the first thread clamping plate 21 The rear of 23. The arm portion 22a of the second thread clamping plate 22 is formed with an overlapping portion 22g of the wired hole 22b and the second thread clamping portion 22c. When the second thread clamping plate 22 is in a predetermined position, such as Figure 5 As shown, the thread hole 22b of the second thread holding plate 22 is located below the needle hole 12a, allowing the sewing needle 11 to pass through the needle hole 12a and the upper thread 7 to penetrate the thread hole 22b. The position where the thread hole 22b overlaps the needle hole 12a below is referred to as the start position (S) of the second thread holding plate 22. The second thread clamping portion 22c of the second thread clamping plate 22 is a part directly related to the clamping action of the upper thread 7, such as Figure 4 Shown is the part of the arm portion 22a that is located to the right of the wire hole 22b.

[0033] Such as Figure 4 As shown, a plate-shaped spring bracket 25 is fixed behind the needle plate 12. The spring holder 25 is arranged behind the second thread holding plate 22, the rear end of the return spring 26 composed of a tension coil spring is attached to the spring holder 25, and the front end of the return spring 26 is attached to the first On the arm 21c of the thread clamping plate 21. The return spring 26 is equivalent to an elastic member and is provided to the first thread clamping plate 21 Figure 4 The counterclockwise rotation force.

[0034] A hub portion 22d is fixed to the bottom plate portion 2, and the hub portion 22d is concentrically fitted with the outer peripheral surface of the second pin 24 of the second wire clamping plate 22. The hub portion 22d is equivalent to the locking member, and the first thread clamping plate 21 is in contact with the hub portion 22d at the stop portion 21d to oppose Figure 4 The counterclockwise rotation is restricted. The position where the rotation of the first thread clamping plate 21 is restricted by the engagement force between the hub portion 22d and the stopper portion 21d is called a clamping position (K). Holding the first thread holding plate 21 at the holding position (K), and holding the second thread holding plate 22 at the starting position (S), the overlapping portion of the second thread holding plate 22 22g is in contact with the first thread holding portion 21b of the first thread holding plate 21 from below.

[0035] Such as Figure 4 As shown, an engagement pin 27 is fixed to the arm portion 22a of the second thread clamping plate 22. The engagement pin 27 protrudes upward from the upper surface of the arm portion 22a and is arranged behind the wire hole 22b. The locking pin 27 is a kind of clamping plate 22 from the second line Figure 4 The starting position (S) is rotated in the clockwise direction based on the member engaged with the first thread clamping plate 21, such as Image 6 As shown, the position where the engagement pin 27 engages with the first thread holding plate 21 is referred to as the holding position (K) of the second thread holding plate 22. When the second thread clamping plate 22 rotates clockwise from the clamping position (K), the first thread clamping plate 21 is pushed by the engagement pin 27 and overcomes the return spring 26 from the clamping position (K) The elastic force is turned clockwise. Picture 8 Shows the state where both the first thread holding plate 21 and the second thread holding plate 22 are rotated from the holding position (K) to the extreme clockwise position, and the clockwise limit of the first thread holding plate 21 The position and the extreme clockwise position of the second thread holding plate 22 are referred to as the release position (L) of the first thread holding plate 21 and the release position (L) of the second thread holding plate 22.

[0036] Such as figure 2 As shown, the upper thread clamping mechanism 20 has a rotating mechanism 35. The rotation mechanism 35 is used to rotate the second thread clamping plate 22 and adopts the following structure.

[0037] Such as figure 1 As shown, a mounting plate 37 is fixed to the inside of the bottom plate body 3, and a wire clamping motor 36 composed of a stepping motor is fixed to the mounting plate 37. This thread clamping motor 36 corresponds to a driving device, and is housed in the rear end portion of the bottom plate 2 on the opposite side to the needle plate 12. The wire clamping motor 36 is arranged downward so that the drive shaft 36a points downward. Such as figure 2 As shown, a handle 38 is fixed on the drive shaft 36a, the connecting plate 39 is rotatably connected with the handle 38 about the shaft 40, and the lower arm 41a of the handle 41 is rotatably connected with the connecting plate 39 about the shaft 43. . The handle 41 has a lower arm portion 41a and an upper arm portion 41b, and is rotatably supported by the base plate body portion 3 via a shaft 42.

[0038] Such as figure 1 As shown, the wire clamping link 45 is housed in the bottom plate portion 2. On the wire clamping link 45, a shape like figure 2 As shown in the convex portion 45b, the convex portion 45b is rotatably connected to the upper arm portion 41b of the handle 41 with the shaft 44 as the center. A connecting pin 46 is fixed to the front end of the wire clamping link 45. The connecting pin 46 protrudes upward from the upper surface of the wire clamping link 45, such as Figure 4 As shown, it is inserted into the engaging hole 22f from below. The engaging hole 22f is formed in the arm portion 22e of the second thread clamping plate 22, and the second thread clamping plate 22 is rotatably connected to the thread clamping link 45 via a connecting pin 46. In addition, figure 2 The symbol 75 denotes a connecting mechanism composed of a handle 38, a connecting plate 39, a handle 41, and a thread clamping link 45. The connecting pin 46 of the thread clamping link 45 is equivalent to the connecting mechanism 75, and the second thread clamping plate 22 The engaging hole 22f corresponds to the connecting portion of the second thread holding member.

[0039] When the drive shaft 36a of the thread clamping motor 36 is at the origin position, such as Figure 4 As shown, the second thread clamping plate 22 is held at the starting position (S). In a state where the second thread clamping plate 22 is held at the starting position (S), the stopper 21d of the first thread clamping plate 21 is engaged with the hub portion 22d to hold the first thread clamping plate 21 at Clamping position (K). In the state where the first thread holding plate 21 and the second thread holding plate 22 are held at the holding position (K) and the starting position (S), as Figure 5 As shown, the thread hole 22b of the second thread clamping plate 22 and the needle hole 12a of the needle plate 12 overlap from below, and the stitching needle 11 can penetrate the thread hole 22b through the needle hole 12a.

[0040] When the drive shaft 36a of the thread clamping motor 36 rotates a set amount from the original position, the operating force acts on the thread clamping link 45 through the handle 38, the connecting plate 39, and the handle 41, and the thread clamping link 45 moves backward . Thus, the second thread clamping plate 22 Figure 4 The starting position (S) of turning clockwise to reach Image 6 The clamping position (K). The angle required to rotate the second thread holding plate 22 from the starting position (S) to the holding position (K) is called the first angle α, and the second thread holding plate 22 is rotated from the starting position (S). The rotation direction of the drive shaft 36a of the wire clamping motor 36 to the clamping position (K) is referred to as the positive direction.

[0041] When the second thread clamping plate 22 reaches the clamping position (K), such as Figure 7 As shown, the second thread gripping portion 22c of the second thread gripping plate 22 overlaps the first thread gripping portion 21b of the first thread gripping plate 21 from below in a contact state, and the second thread gripping plate 22 The thread hole 22b is blocked by the first thread holding portion 21b of the first thread holding plate 21. When the thread hole 22b is closed, the thread end 7a of the upper thread 7 is located between the second thread gripping portion 22c of the second thread gripping plate 22 and the first thread gripping portion 21b of the first thread gripping plate 21 Clamping. The thread end 7a refers to the end of the upper thread 7 extending from the hole 11a of the needle 11, and the thread end 7a is clamped after the second thread clamping plate 22 reaches the clamping position (K) Between the first thread holding plate 21 and the second thread holding plate 22. In this state, the thread end 7a is located outside the rotation track of the tip 15d of the vertical shuttle 15, and the thread end 7a can be prevented from being caught by the tip 15d.

[0042] When the second thread clamping plate 22 reaches the clamping position (K), such as Image 6 As shown, the engaging pin 27 of the second thread holding plate 22 is in contact with the first thread holding plate 21. In this state, when the drive shaft 36a of the thread clamping motor 36 rotates by a set amount, the thread clamping link 45 linearly moves backward. Next, the second thread clamping plate 22 Image 6 The clamping position (K) rotates clockwise to reach Picture 8 The release position (L). At this time, the first thread holding plate 21 is pushed by the engagement pin 27 of the second thread holding plate 22, and together with the second thread holding plate 22, it reaches the release position (L) from the holding position (K). The angle required for the second thread clamping plate 22 to rotate from the clamping position (K) to the release position (L) is referred to as a second angle α2.

[0043] When the first pin 23 of the first thread holding plate 21 and the second pin 24 of the second thread holding plate 22 are misaligned with each other, and the second thread holding plate 22 moves from the holding position (K) to the release position (L) The movement amount of the thread hole 22b is different from the movement amount of the first thread gripping portion 21b when the first thread gripping plate 21 moves from the grip position (K) to the release position (L). Therefore, when both the first thread clamping plate 21 and the second thread clamping plate 22 reach the release position (L), as Picture 8 As shown, the thread hole 22b of the second thread holding plate 22 and the first thread holding portion 21b of the first thread holding plate 21 are misaligned with each other. Picture 9 As shown, on the basis of the partial opening of the thread hole 22b, the thread end 7a of the upper thread 7 becomes the released state. In this state, the thread end 7a is located outside of the rotation track of the tip 15d of the vertical shuttle 15, which prevents the thread end 7a from being caught by the tip 15d. That is, the thread end portion 7a of the upper thread 7 is in the released state after both the first thread holding plate 21 and the second thread holding plate 22 reach the releasing position (L).

[0044] With the first thread clamping plate 21 and the second thread clamping plate 22 in the release position (L), the thread clamping motor 36 is turned on, and when the drive shaft 36a of the thread clamping motor 36 is reversed, the operation The force is transmitted to the wire clamping link 45 through the handle 38, the connecting plate 39, and the handle 41, and the wire clamping link 45 moves forward. Thus, the second thread clamping plate 22 Picture 8 The release position (L) via Image 6 The clamping position (K) returns Figure 4 The starting position (S). The rotation direction of the drive shaft 36a of the thread grip motor 36 for returning the second thread gripping plate 22 from the release position (L) to the start position (S) is referred to as a reverse direction.

[0045] When the second thread clamping plate 22 returns to the starting position (S) from the release position (L), the engagement pin 27 of the second thread clamping plate 22 moves together with the second thread clamping plate 22, so the first thread clamp The holding plate 21 uses the elastic force of the return spring 26 to move toward Picture 8 To turn counterclockwise. The rotation of the first thread holding plate 21 in the counterclockwise direction is restricted by the contact between the stopper 21d of the first thread holding plate 21 and the hub part 22d, and the first thread holding plate 21 is at the stopper 21d. After contact with the hub portion 22d, it returns to the clamping position (K). That is, the first thread clamping plate 21 returns from the release position (L) to the clamping position (K) by the elastic force of the return spring 26.

[0046] Such as figure 2 As shown, an origin sensor 48 made of a magnetic sensor is fixed to the mounting plate 37, and when the detection portion 39a made of a magnetic material enters the detection area of ​​the origin sensor 48, the origin sensor 48 outputs a high-level origin signal. The detection portion 39 a is formed on the connecting plate 39, and when the second thread clamping plate 22 is at the start position (S), the detection portion 39 a enters the detection area of ​​the origin sensor 48. That is, the origin sensor 48 detects that the second thread holding plate 22 is at the start position (S), and corresponds to the first detector that outputs the origin signal.

[0047] Such as figure 2 As shown, a mounting plate 50 is fixed inside the bottom plate body 3. A release sensor 49 made of a magnetic sensor is fixed to the mounting plate 50. When the detection portion 45a made of a magnetic material enters the detection area of ​​the release sensor 49, the release sensor 49 outputs a high-level origin signal. The detection portion 45a is formed on the thread clamping link 45, and when the second thread clamping plate 22 is at the release position (L), the detection portion 45a enters the detection area of ​​the release sensor 49. That is, the release sensor 49 detects that the second thread clamping plate 22 is at the release position (L), and corresponds to a second detector that outputs a release signal.

[0048] Picture 10 The control device 55 is equivalent to the control device and is composed of a microcomputer as the main body. The control device 55 has an input interface 56, a CPU 57, a ROM 58, a RAM 59, an output interface 60, a drive circuit 61, a drive circuit 62, a drive circuit 63, a drive circuit 64, a drive circuit 65, a drive circuit 66, and a drive circuit 66c. The drive circuit 61 and the drive circuit 62 are connected to the sewing machine motor 67 and the pressing motor 68, and the drive circuit 63 is connected to the thread clamping motor 36. The drive circuit 61 and the drive circuit 62 drive the sewing machine motor 67 and the pressing motor 68 according to the drive signal from the CPU 57 The drive circuit 63 drives the wire clamp motor 36 in accordance with the drive signal from the CPU 57. The drive circuit 64 is connected to the thread trimming solenoid 69, and the drive circuit 64 drives the thread trimming solenoid 69 according to a drive signal from the CPU 57. The drive circuit 65 and the drive circuit 66 are connected to the X-axis drive motor 70 and the Y-axis drive motor 71, and the drive circuit 65 and the drive circuit 66 drive the X-axis drive motor 70 and the Y-axis drive motor 71 according to the drive signal from the CPU 57. The drive circuit 66c is connected to the liquid crystal display 9a, and the drive circuit 66c displays content corresponding to the drive signal on the liquid crystal display 9a based on the drive signal from the CPU 57.

[0049] On the input interface 56 of the control device 55, such as Picture 10 As shown, a selection switch 9b, a thread clamping mode switch 9c, a setting switch 9d, an initial setting switch 9e, a first switch 18a, a second switch 18b, an origin sensor 48, a release sensor 49, and an encoder 73 are connected. The first switch 18a is turned on when the pedal 18 is depressed to the first gear pressing position, and the CPU 57 detects that the first switch 18a is turned on, and determines that the pedal 18 has been depressed to the pressing position. The second switch 18b is turned on when the pedal 18 is depressed to the sewing position of the second step, and the CPU 57 detects that the second switch 18b is turned on, and determines that the pedal 18 has been depressed to the sewing position. The encoder 73 is a rotary member that outputs a pulse signal every time the amount of rotation of the spindle reaches a unit value (for example, 1 degree). The CPU57 measures the number of pulse signals output from the encoder 73 at 1 The rotation phase angle of the spindle is detected in the range of degrees to 360 degrees (0 degrees).

[0050] The control program and control data are recorded in the ROM 58 of the control device 55. According to the control program and the control data, the CPU 57 of the control device 55 controls the sewing machine motor 67, pressing motor 68, thread clamping motor 36, thread trimming solenoid 69, X The shaft drive motor 70 and the Y-axis drive motor 71 are controlled to form a bartacking reinforcement stitch on the processed cloth W. Next, the control content of the control device 55 will be described.

[0051] When the CPU57 of the control device 55 is powered on, Picture 11 In step S11 of, the operation state of the initial setting switch 9e is judged. Here, when it is detected that the initial setting switch 9e has been turned on, after the origin setting process of step S12, it proceeds to step S13. When it is detected that the initial setting switch 9e is not turned on, the origin setting of step S12 is skipped. After the predetermined processing, it proceeds to step S13. The origin setting process of this step S12 is based on the reversal of the drive shaft 36a of the thread clamp motor 36 and is initially set to the origin position. When the drive shaft 36a of the thread clamp motor 36 is initially set to the origin position, The second thread clamping plate 22 is in contact with a stopper (not shown) and is positioned at the start position (S).

[0052] Once the process proceeds to step S13, the CPU 57 determines whether the first switch 18a is on or off. For example, when the operator places the processed cloth W on the throat plate 12 and depresses the pedal 18 to the cloth pressing position of the first gear, the first switch 18a is turned on, and the CPU 57 turns on the first switch 18a in step S13. Detect, and proceed to step S14.

[0053] Once moving to step S14, the CPU 57 moves and operates the presser foot 13 to the cloth press position according to the driving of the press motor 68, and the processed cloth W on the needle plate 12 is pressed by the presser foot 13 from above. Then, it moves to step S15, and judges whether the 2nd switch 18b is ON/OFF. For example, when the operator depresses the pedal 18 to the sewing position of the second step, the second switch 18b is turned on, and the CPU 57 detects that the second switch 18b is turned on in step S15, and proceeds to step S16.

[0054] Once the process proceeds to step S16, the CPU 57 determines whether the thread clamp mode switch 9c is turned on or off. Here, when it is detected that the thread clamping mode switch 9c has been turned on, it proceeds to step S17, and it is determined whether there is an origin signal. When the origin signal is detected, the process proceeds to step S21, and when the absence of the origin signal is detected, the process proceeds to step S18.

[0055] Once the process proceeds to step S18, the CPU 57 reverses the thread clamping motor 36, determines the presence or absence of the origin signal in step S19, and compares the measured value of the reverse time with the upper limit value in step S20. This reversal time is the time when the CPU57 starts to measure the state where the thread clamp motor 36 starts to reverse in step S18. Before the measured value of the reversal time reaches the upper limit, when the CPU57 detects in step S19 When the origin signal is reached, it proceeds to step S21. In addition, when the origin signal is not detected and it is detected in step S20 that the measured value of the reversal time has reached the upper limit value, the process proceeds to step S22. At this time, an error message is displayed on the liquid crystal display 9a, and the operation is terminated. That is, after the thread clamp motor 36 starts to reverse, if the second thread clamp plate 22 does not reach the start position (S) even after the set time has passed, it is determined that an abnormality has occurred and the operation is terminated.

[0056] Once the process proceeds to step S21, the CPU 57 drives the sewing machine motor 67. Then, the needle bar 10, the thread take-up lever 72, and the feed plate 14 are activated, and the sewing process is started. Picture 12 It is a time chart showing the movement of the sewing needle 11 and the movement of the thread take-up lever 72 in the time series. The Picture 12 The horizontal axis represents the rotation phase angle of the main shaft, the vertical axis represents the vertical position (referred to as the height position) of the needle 11 and the thread take-up lever 72, and the dashed line represents the height position of the upper surface of the needle plate 12. Such as Picture 12 As shown, every time the main shaft rotates 360 degrees, the needle 11 moves from the top dead center to the bottom dead center back to the top dead center. On the way from the top dead center to the bottom dead center, from the needle hole of the needle plate 12 12a penetrates through the thread hole 22b of the second thread holding plate 22, and comes out of the thread hole 22b of the second thread holding plate 22 and the needle hole 12a of the needle plate 12 while moving from the bottom dead center to the top dead center. . The sewing needle 11 comes out of the needle hole 12a of the needle plate 12, and while ascending, the thread take-up lever 72 ascends to tighten the stitch.

[0057] in Picture 11 In step S21, when the sewing process is started, in step S23, the CPU 57 detects the rotation phase angle θ of the spindle based on the output signal from the encoder 73, and compares the detection result of the rotation phase angle θ with the download pre-recorded in the ROM 58 The limit value of 0 degrees is compared with the upper limit value of 30 degrees. Here, when it is detected that the detection result of the rotation phase angle θ is within the range of the lower limit value 0 degrees to the upper limit value 30 degrees, it is determined that the gripping time point has been reached, and the process proceeds to step S24. When the rotation phase angle of the spindle is in the range of 0 degrees to 30 degrees, such as Picture 12 As shown, the sewing needle 11 escapes from the needle hole 12a of the needle plate 12, and the stitch is tightened as the thread take-up lever 72 rises.

[0058] Once moved to Picture 11 In step S24, the CPU 57 adds a set number of pulse signals to the thread clamp motor 36 in the forward rotation mode, and then rotates the thread clamp motor 36 forward. This pulse signal can only make the drive shaft 36a of the thread clamp motor 36 rotate forward by the first angle α1, and the second thread clamp plate 22 rotates forward from the start position (S) according to the thread clamp motor 36 in step S24. To the clamping position (K). That is, the second thread clamping plate 22 moves from the starting position (S) to the clamping position (K) when the stitch of the first needle is tightened. In this state, as the stitches are tightened, the length of the thread end portion 7a is reduced to about 2 cm to 3 cm, and as the second thread clamping plate 22 reaches the clamping position (K) in step S24, 2 cm to 3 cm The wire end portion 7 a of the left and right length is clamped between the first wire clamping plate 21.

[0059] In step S24, once the thread end portion 7a of the upper thread 7 is clamped, the CPU 57 determines the presence or absence of the origin signal in step S25. Here, when the origin signal is detected, the sewing machine motor 67 is turned off in step S26, and an error message is displayed on the liquid crystal display 9a in step S27. That is, in step S24, even if a pulse signal is applied to the thread clamping motor 36, when the second thread clamping plate 22 does not move from the start position (S), it is determined that an abnormality has occurred and the sewing process is terminated.

[0060] If no origin signal is detected in step S25, the CPU 57 waits in step S28 until a stitch with a set number of stitches (for example, 3 stitches) is formed. The number of needles is recorded in the ROM 58 of the control device 55 in advance. The CPU 57 detects the rotation amount of the main shaft based on the measurement of the pulse signal from the encoder 73 in step S28, and determines that a stitch with the set number of stitches has been formed based on the detection result of the rotation amount. That is, during the period from the tension of the first stitch to the formation of the third stitch, the thread end 7a of the upper thread 7 continues to be clamped between the first thread clamping plate 21 and the second thread clamping plate 22, and the second The needle stitch and the third needle stitch are formed in the pinched state of the thread end 7a.

[0061] If it is determined in step S28 that the stitches of the set number of stitches have been formed, the CPU 57 adds the set number of pulse signals to the thread clamping motor 36 in the forward rotation mode in step S29 to make the thread clamping motor 36 36 forward rotation. This pulse signal can only rotate the drive shaft 36a of the thread clamping motor 36 by the second angle α2, and the second thread clamping plate 22 rotates forward from the clamping position (K) according to the thread clamping motor 36 in step S29. When it reaches the release position (L), the thread clamp motor 36 is held at the release position (L) by its own holding force. That is, the thread end 7a of the upper thread 7 is released under the condition that the third stitch is formed, and the subsequent sewing process is performed when the first thread holding plate 21 and the second thread holding plate 22 are moved to the release position ( L) is performed in the released state of the wire end 7a.

[0062] If a pulse signal is added to the thread clamping motor 36 in step S29, the CPU 57 determines whether there is a cancellation signal in step S30. Here, when no cancellation signal is detected, the sewing machine motor 67 is turned off in step S26, and an error message is displayed on the liquid crystal display 9a in step S27. That is, even if a pulse signal is applied to the thread clamping motor 36 in step S29, when the second thread clamping plate 22 has not reached the release position (L), it is determined that an abnormality has occurred, and the sewing process is ended.

[0063] If the release signal is detected in step S30, the CPU 57 determines whether the second switch 18b is on or off in step S31. For example, when the operator removes the foot from the pedal 18, the pedal 18 returns to the initial position from the sewing position, and the second switch 18b is turned off. In this case, the CPU 57 detects the turning off of the second switch 18b in step S31, and turns off the sewing machine motor 67 in step S32. Then, the movements of the sewing needle 11, the thread take-up lever 72, and the feed plate 14 are stopped, and the sewing process is ended.

[0064] When the sewing process is finished in step S32, the CPU 57 proceeds to the thread trimming process in step S33. Here, with the drive of the thread trimming solenoid 69, the movable knife 31 performs a rotating operation to cut both the upper thread 7 and the lower thread between the movable knife 31 and the fixed knife 30, and then moves to step S34 in the reverse mode The set number of pulse signals are added to the thread clamp motor 36. This pulse signal can only reverse the drive shaft 36a of the thread clamping motor 36 by "first angle + second angle". The second thread clamping plate 22 reverses the drive shaft 36a of the thread clamping motor 36 in step 34. Turning "1st angle + 2nd angle", relying on the driving force of the thread clamp motor 36 to return to the start position (S) from the release position (L), as the second thread clamp plate 22 returns from the release position (L) to start When the position (S) is rotated, the first thread clamping plate 21 returns to the clamping position (K) from the release position (L) by the elastic force of the return spring 26.

[0065] If it is detected in step S16 that the thread clamp mode switch 9c has been turned off, the CPU 57 adds the set number of pulse signals to the thread clamp motor 36 in the forward rotation mode in step S35 to cause the thread clamp motor 36 to rotate forward. . Then, the second thread clamping plate 22 is rotated from the start position (S) to the release position (L), and the first thread clamping plate 21 is rotated from the clamping position (K) to the release position (L).

[0066] If a pulse signal is added to the thread clamp motor 36 in step S35, the CPU 57 determines whether there is a cancellation signal in step S36. Here, when no cancellation signal is detected, the process proceeds to step S22, an error message is displayed on the liquid crystal display 9a, and the operation is terminated. That is, even if a pulse signal is applied to the thread clamping motor 36 in step S35, when the second thread clamping plate 22 has not reached the release position (L), it is determined that an abnormality has occurred, and the operation is terminated.

[0067] If the CPU 57 detects the release signal in step S36, it moves to step S37. Here, the sewing process is started by turning on the sewing machine motor 67, and the process proceeds to step S31. That is, in the closed state of the thread clamping mode switch 9c, the sewing process is performed without clamping the thread end portion 7a of the upper thread 7.

[0068] If it is detected in step S31 that the second switch 18b has been turned off, the CPU 57 terminates the sewing process based on the off state of the sewing machine motor 67 in step S32. Then, according to the driving of the thread trimming solenoid 69 in step S33, the upper thread 7 and the lower thread are cut, and a set number of pulse signals are applied to the thread clamping motor 36 in the reverse mode in step S34 to make The second thread clamping plate 22 returns from the release position (L) to the start position (S), and the first thread clamping plate 21 returns from the release position (L) to the clamping position (K).

[0069] With the above embodiment, the following effects can be obtained.

[0070] When the second thread holding plate 22 is at the start position (S), the needle hole 12a of the needle plate 12 and the thread hole 22b of the second thread holding plate 22 are aligned in the vertical direction. In this state, when the sewing needle 11 descends, it enters the thread hole 22b from the needle hole 12a, and when the sewing needle 11 rises, it escapes from the thread hole 22b and the needle hole 12a. When the needle 11 is pulled out, the thread end 7a of the upper thread 7 remains in the thread hole 22b of the second thread holding plate 22. With the thread end 7a remaining in the thread hole 22b, when the second thread clamping plate 22 moves from the starting position (S) to the clamping position (K), the thread end 7a is clamped at the first thread Between the clamping plate 21 and the second thread clamping plate 22, when the second thread clamping plate 22 moves from the clamping position (K) to the release position (L), the thread end portion 7a is released. In this way, the thread end portion 7a can be clamped from the start of sewing until the stitch of the set number of stitches is formed, so that stitch skipping at the start of sewing can be prevented. Then, the second thread clamping plate 22 is rotated between the start position (S), the clamping position (K), and the release position (L). In this way, since there is no need for a plurality of links that guide the linear movement direction of the second thread holding member 22, a member supporting the plurality of links, and a plurality of air cylinders that generate the moving force of the second thread holding member, etc., Therefore, the structure of the upper thread clamping member 20 can be simplified. In addition, since the second thread gripping plate 22 is moved from the start position (S) to the release position (L), the thread gripping motor 36 is housed in the rear end portion of the bottom plate 2 on the opposite side to the needle plate 12 Therefore, it is possible to prevent the bottom plate portion 2 from being enlarged due to the influence of the thread clamping motor 36.

[0071] Set the clamping position (K) of the second thread clamping plate 22 at a position where the second thread clamping plate 22 is rotated from the starting position (S) to the set direction by the first angle α1, and the second thread clamping The release position (L) of the holding plate 22 is set at a position where the second thread holding plate 22 is rotated from the holding position (K) by a second angle α2 in the same direction as the setting direction. In this way, corresponding to the rotation of the second thread holding plate 22, the second thread holding plate 22 is separated from the sewing needle 11, and when the second thread holding plate 22 reaches the release position (L), it is farthest from the sewing needle 11 Therefore, it is possible to prevent the thread end 7a from being sewn into the processed cloth W when the sewing process is performed.

[0072] The first thread holding plate 21 is pushed by the engagement pin 27 of the second thread holding plate 22 and operated from the holding position (K) to the release position (L), and is moved from the release position (L) by the elastic force of the return spring 26 L) Return to the clamping position (K), so there is no need to provide a dedicated actuator for reciprocating the first thread clamping plate 21 between the clamping position (K) and the release position (L).

[0073] The first thread clamping plate 21 is held at the clamping position (K) by the engaging force between the stopper portion 21d and the hub portion 22d. In this way, the first thread holding plate 21 can be reliably held at the holding position (K), so that the thread of the upper thread 7 can be reliably held between the first thread holding plate 21 and the second thread holding plate 22 The end 7a is clamped.

[0074] The first pin 23 of the first thread holding plate 21 is arranged on the rear side of the needle hole 12a of the needle plate 12, and the second pin 24 of the second thread holding plate 22 is arranged on the rear side of the first pin 23, so , The release position (L) of the first thread clamping plate 21 and the release position (L) of the second thread clamping plate 22 are shifted from each other, so that both the first thread clamping plate 21 and the second thread clamping plate 22 When the release position (L) is reached, the thread hole 22b of the second thread clamping plate 22 can be reliably opened, so the clamping of the thread end 7a can also be reliably released, and there is no need to release the thread end 7a The special clamping mechanism can make the upper thread clamping mechanism 20 small and simple.

[0075] When the second thread holding plate 22 is at the start position (S), the overlapping portion 22g of the second thread holding plate 22 overlaps the first thread holding plate 21 from below, and when the second thread holding plate 22 moves from When the starting position (S) is moved to the clamping position (K), the second thread clamping plate 22 and the first thread clamping plate 21 will not collide. In this way, the second thread clamping plate 22 can be smoothly moved from the starting position (S) to the clamping position (K) at the set speed, so that the thread end 7a of the upper thread 7 can be quickly clamped.

[0076] The control device 55 adopts a structure in which the second thread gripping plate 22 is positioned at the starting position (S) based on the initial setting of the thread gripping motor 36. In this way, the second thread clamping plate 22 is positioned at the start position (S) when the power is turned on, and when the sewing process is started after the pedal 18 is depressed to the sewing position immediately after the power is turned on, the sewing needle 11 does not It will collide with the second thread clamping plate 22.

[0077] The origin sensor 48 is used to detect that the second thread clamping plate 22 is at the start position (S). In this way, it can be detected that the second thread clamping plate 22 is not in an abnormal state at the start position (S), and an error message can be displayed or the operation can be stopped.

[0078] The release sensor 49 detects that the second thread clamping plate 22 is at the release position (L). Thereby, it is possible to detect an abnormal state in which the second thread clamping plate 22 is not at the release position (L), display an error message or stop the operation.

[0079] The first thread holding plate 21 and the second thread holding plate 22 are used to place the thread end 7a of the upper thread 7 in the left area (the area biased to the shorter side of the bottom plate 2) directly below the sewing needle 11. Clamping structure. In this way, since the thread end 7a is far away from the sewing needle 11, the thread end 7a can be prevented from being sewn into the processed cloth W during the sewing process.

[0080] Since the first thread holding plate 21 and the second thread holding plate 22 are rotatably mounted on the needle plate 12, the first thread holding plate 21 and the second thread holding plate 22 are integrated with the needle plate 12. Then, the connecting pin 46 is fixed to the wire clamping link 45 upward, and the connecting pin 46 is inserted into the engagement hole 22f of the second wire clamping plate 22. In this way, the multiple screws used to fix the needle plate 12 on the bottom plate 2 are removed, and the engagement between the connecting pin 46 and the engaging hole 22f can be released by simply lifting the needle plate 12, and the needle plate 12 and The first thread holding plate 21 and the second thread holding plate 22 are taken out from the bottom plate 2 together, so that foreign objects such as thread ends and dust attached to the lower surface of the needle plate 12 can be easily cleaned.

[0081] In the above embodiment, the first thread clamping plate 21 is rotatably installed on the needle plate 12, but it is not limited to this example, for example, it may be installed in a stationary state. In this case, the thread hole 22b of the second thread holding plate 22 can pass through the first thread holding plate 21 when the second thread holding plate 22 is rotated from the holding position (K) to the release position (L). It is required to arrange the first thread holding plate 21, and since the thread hole 22b passes through the first thread holding plate 21, the holding of the thread end 7a can be released.

[0082] In the above-mentioned embodiment, the second thread clamping plate 22 can also face and Figure 4 Rotate in the opposite direction to the left and right to place the first thread clamping plate 21 in Figure 4 Arranged in the opposite left and right directions, and the second thread clamping plate 22 facing and Figure 4 The counterclockwise rotation, on this basis, moves the operation to the clamping position and the release position.

[0083] In the above-mentioned embodiment, a stepping motor is used as the wire clamping motor 36, but it is not limited to this example. For example, a DC motor that can be feedback controlled may be used.

[0084] In the above-mentioned embodiment, as the driving means for rotating the second thread clamping plate 22 from the starting position (S) to the clamping position (K), the thread clamping motor 36 is used. It is not limited to this example, and it may be, for example, Use linear solenoids.

[0085] In the above-mentioned embodiment, an oscillating shuttle is used as the vertical shuttle 15, but it is not limited to this example. For example, a rotary shuttle may also be used.

[0086] In the above-mentioned embodiment, a circular thread hole 22b is formed on the second thread holding plate 22, but it is not limited to this example. For example, a left-right long elliptical or polygonal thread hole may be formed.

[0087] The present invention is not limited to the embodiments described above, and can be applied to various sewing machines having various upper thread clamping mechanisms including a first thread clamping member and a second thread clamping member provided on the lower side of the needle plate.