JPH06248561A - Method for sewing - Google Patents

Abstract

PURPOSE:To enable the easy start of sewing by preventing the needle point from piercing yarn in starting the sewing. CONSTITUTION:In the case of starting the sewing, when the starting position of a yarn leadout hole 17 in a looper 15 is located in a section holding a relationship in which the needle point in the course of lowering is brought into contact with yarn led out of the yarn leadout hole, the starting position is previously removed from the section. Otherwise, the rotational speed of the yarn leadout hole is changed in the course thereof to eliminate the relationship of the contact.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method in which a hook needle is lowered through a cloth, a thread is wound around the lowered hook needle by a looper, and then the hook needle is lifted and the cloth is laterally moved. The method of performing sewing on.

[0002]

2. Description of the Related Art When starting sewing by the above-mentioned method, it is necessary to surely wind a thread, which is led out from a thread leading-out hole in a looper and has its end free, around the hook needle. First, the thread is pulled up on the needle plate through the thread passing hole of the needle plate, and the sewing is started from that state.

[0003]

This conventional sewing method has a problem in that the thread has to be pulled up onto the needle plate each time sewing is started. Therefore, in order to facilitate the start of sewing, a technique is proposed in which the end of the thread is grasped at a position on the side of the looper and the thread is securely wound around the hook needle. Was issued. However, in this case, there is a problem in that the needle tip of the hook needle that has descended at the start of sewing pierces the thread between the thread outlet hole and the holding position of the thread end, making it impossible to sew. there were.

The present invention has been made in order to solve the above-mentioned problems (technical problems) of the prior art. It is possible to prevent the needle tip from sticking into the thread and facilitate the start of the sewing. It is an object of the present invention to provide a sewing method capable of enjoying the effect.

[0005]

In order to achieve the above object, the sewing method according to the present invention comprises a step of laterally moving the cloth every time the hook needle moves up and down, and a hook portion in a direction opposite to the moving direction of the cloth. Repeat the process of vertically moving the hook needle with the opening facing, and start the looper thread lead-out hole on the opposite side of the opening in order to hook the thread on the hook while the hook needle rises from the bottom dead center. From the step of starting from the position to rotate around the vertical movement locus of the hook needle and the thread holding means arranged on the side of the looper until at least the first time when the thread is pulled up by the hook needle at the beginning of sewing. In a sewing method including a step of gripping an end of a thread, a start position of the thread lead-out hole is set to a thread between a thread lead-out hole which is in the middle of rotation and a position where the thread holding means grasps the end of the thread. On the other hand, the needle tip that is in the process of descending contacts If there is a section which is that relationship,
In order to eliminate the abutting relationship, the start position is removed from the section in advance, or the rotation speed of the yarn outlet hole is changed midway.

[0006]

When sewing is started, the end of the thread drawn out from the thread drawing hole is held in advance by the thread holding means. In that state, the hook needle descends, and the thread lead-out hole rotates around the hook needle. Since the end of the yarn drawn out from the yarn drawing hole is held, the yarn is surely wound around the hook needle. After that, the hook needle rises and the thread is pulled up. When there is a possibility that the needle tip may pierce the thread when the hook needle descends, the start position of the thread lead-out hole is shifted in advance. Alternatively, the rotation speed of the yarn outlet hole is changed. Therefore, the needle tip does not stick to the thread.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Prior to the description of the embodiments of the present application, FIGS. 1 to 25 showing the technology underlying the present application will be described. 1 to 4 show one bed A in a multi-head multicolor sewing machine. A plurality of such beds A are arranged side by side in the left-right direction in FIG. Although not shown, a sewing machine head is provided at a spatially upper position of each bed A. FIG. 3 shows a vertically movable needle hook B for sewing which is provided on the sewing machine head. C indicates a base frame of the bed A, and D indicates a looper device.

The base frame C will be described. Reference numeral 1 is a frame, and 2 is a top plate for supporting a material to be sewn or an embroidery frame, which is detachably attached (for example, bolted) to the frame 1 for maintenance of various members attached to the frame. A needle plate 3 has a needle drop hole 4 and a thread pulling hole, and is detachably attached to the top plate.

The looper device D will be described. Reference numeral 6 denotes a rail attached to the frame 1, which is formed to be long in the direction perpendicular to the paper surface of FIG. Reference numeral 7 denotes a looper table, which can be moved horizontally along the rail 6 by a slide body 8 attached to the lower surface. The moving direction may be a direction that draws an arc locus in the horizontal plane. Reference numeral 9 denotes a looper assembly, which is arranged in parallel in the moving direction of the looper base 7 so that the needle drop position can be selectively reached by the lateral movement of the looper base 7. Figure 1
Reference numeral 10 is a member for moving the looper base 7 laterally, and in this example, a lateral movement rod inserted through the frame 1 is shown. The looper table 7 is fixed to the lateral movement rod 10, and an end portion of the lateral movement rod 10 which is not shown is connected to a driving device for laterally moving the looper table 7. 11
Is a drive device for rotationally driving the looper at the needle drop position, 12 is an elevating device for vertically moving the looper at the needle drop position between an upper operating position and a lower retracted position, and 13 is at a retracted position Each of the holding mechanisms for holding the looper in a predetermined preparation position in the rotation direction is shown.

FIG. 6 showing the looper assembly 9 will be described. Reference numeral 14 denotes a looper shaft for rotatably and vertically movingly supporting the looper, which is attached to the looper base 7 so as to be rotatably and vertically movable. The looper shaft 14 is hollow for thread insertion.
A known looper 15 is fixed to the looper shaft 14 and has a needle drop hole 16 and a thread lead-out hole 17 communicating with the hollow portion. 18 is the looper
It is a passive gear for transmitting rotational driving force to 15, and is attached to the looper shaft 14. Numeral 19 is a cam for locating the looper 15 in the rotating direction, which is provided with an engaging recess 20, and is attached to the looper shaft 14 by a set screw 19a for attachment as shown in FIG. Reference numeral 21 shown in FIG. 3 is a connecting body for transmitting the lifting drive force from the lifting device 12 to the looper 15, and an engaging piece 22 with the lifting device is provided at the tip end.
Bearings 24 are provided at the base to prevent rotation relative to the looper shaft 14 and to integrally integrate them in the axial direction.
It is installed at.

The drive device 11 will be described. Reference numeral 31 denotes a housing which houses a gear for connection, and is attached to the frame 1. 32 is a lid of the housing 31. 33 is the main axis,
Horizontally installed so as to penetrate the frame 1 and the housing 31,
A drive source such as a motor is connected to one end (not shown). Reference numeral 35 denotes a drive shaft for driving the looper, which is connected to the main shaft 33 via gears 34 and 36 for connection in the housing 31. Reference numeral 37 is a drive gear for rotationally driving the looper, which is fixed to the shaft 35. Reference numeral 38 is a guide gear for guiding the engagement of the passive gear 18 with the drive gear 37, and includes a toothed portion 39 and a toothless portion 40 as shown in FIG. The toothed portion 39 has the same diameter as the drive gear 37,
They are formed at the same pitch. The range of the toothless portion 40 is made large enough to prevent meshing with the passive gear when it moves laterally as described later. The guide gear 38 is attached to the drive shaft 35 in a state where the teeth of the drive gear 37 and the teeth of the toothed portion 39 are continuous. In this example, the guide gear 38 and the drive gear 37 are integrally formed.

The holding mechanism 13 will be described. 41 is a base plate fixed to the looper base 7, 42 is a detent piece for engaging with the cam 19, and as shown in FIG. 7, there are provided a number corresponding to the cam 19 of each looper assembly 9, and each is formed into a round bar shape. Mounted on the substrate 41. Reference numeral 43 denotes an operation window for operating the mounting screw 19a, which is formed at a position and size facing the mounting screw 19a of the cam 19 in all the looper assemblies 9 in the retracted position as shown in FIG. Reference numeral 44 denotes a member for guiding the connecting body 21 up and down without rotating, which is engaged with the rotation stopping piece 23. Reference numeral 45 shown in FIGS. 1 and 8 denotes a separation restricting member for preventing the recess 20 of the cam 19 from coming off the rotation stopper 42. As is clear from FIG. 8, the position in the height direction is the retracted position. The gap between the upper surface of the passive gear 18 at
A position which is provided at a position smaller than the fitting depth of the anti-rotation piece 42 in the recess 20 and overlaps with the passive gear 18 related to the looper 15 other than the looper 15 which is in the needle drop position in plan view as shown in FIG. And is attached to the housing 31 for fixing to the frame 1.

Next, the operation of the embroidery sewing machine will be described. During normal sewing, the looper assembly 9 at the needle drop position, that is, the looper assembly 9 at the position where the needle drop hole 16 of the looper 15 and the needle drop hole 4 of the needle plate 3 overlap each other, is moved by the lifting mechanism 12. Raised and in the actuated position as shown in FIG. 3, its passive gear 18 meshes with the drive gear 37. The main shaft 33 is reciprocally rotated, and the looper 15 is reciprocally rotated through the gears 34, 36, the drive shaft 35, the drive gear 37, and the passive gear 18 as is well known. As is well known, this rotation is synchronized with the vertical movement of the sewing hook B. Further, on the top plate 2, the cloth stretched on the embroidery frame is intermittently laterally moved in synchronization with the vertical movement of the hook needle B. As a result, the above-mentioned cloth is sewn on the needle plate 3 by the sewing thread 46 supplied through the thread lead-out hole 17 of the looper 15. In the case of the above-mentioned sewing, the direction of the hook portion of the hook needle B is determined according to the sewing method and the moving direction of the cloth as is well known, and when chain stitching is performed, the thread is prevented from coming off from the hook portion easily. In the case of the sewing method in which the thread is simply pulled up from the cloth for each stitch (the sewing method called loop sewing), it is in the same direction so that the thread can be easily removed. The direction of the starting point where the looper 15 rotates, for example, the direction of the yarn lead-out hole 17 with respect to the needle drop hole 16,
As is well known, it is determined according to the direction of the hook portion so that the thread is reliably hooked to the hook portion. For example, the thread lead-out hole 17 faces the side opposite to the hook portion direction with respect to the needle drop hole 16. To be

Next, the looper 15 for changing the thread used for sewing
Explain the exchange. The state in which the needle B is located at the top dead center and the looper 15 is located at the origin in the rotating direction, for example, the thread lead-out hole 17 is the needle drop position in FIG. 2 (position in which it is in a state of being connected to the drive gear 37).
The sewing machine is stopped when it reaches the 9 o'clock position of the timepiece like the looper 15 at. Next, the thread after sewing is cut manually or by a thread cutting device described later. Next, the lifting device 12
Thus, the looper assembly 9 at the needle drop position is lowered to the retracted position as shown in FIG.

In this state, the passive gear 18 is shown in FIG.
As shown in the middle figure (this figure is the view from the bottom side), it meshes with the toothed portion 39 of the guide gear 38,
19 is on the detent 42. Next, in that state, the guide gear 38 is rotated by the main shaft 33 in the arrow X direction. In the rotating process, as shown in FIG. 9 (A), when the passive gear 18 meshes with the toothed portion 39 of the guide gear 38, the passive gear 18 interlocks with the rotation of the guide gear 38 in the arrow X direction. Rotate. Eventually, as shown in FIG. 9B, when the passive gear 18 comes out from the toothed portion 39 of the guide gear 38 to the toothless portion 40,
Then, the rotation of the passive gear 18 is stopped. At the time of this stop, as shown in the figure,
20 engages with the detent piece 42. As a result, the position of the looper 15 in the rotational direction is determined by the passive gear 18 being the toothed portion 39 of the guide gear 38.
The thread lead-out hole 17 is held at the 12 o'clock position of the timepiece (this position is called the preparation position) like the looper 15 at a position other than the needle drop position in FIG. In order to achieve such a state, the positional relationship of the cam 19 with the passive gear 18 in the turning direction is adjusted in advance. The adjustment is a recess
When 20 is engaged with rotation stopper 42, the mounting screw
This is done by loosening 19a, turning the looper 15 together with the shaft 14 to a predetermined preparation position, and then tightening the screw 19a. The work is performed through the window 43 from the front side of the sewing machine.

Continuing, the guide gear 38 is indicated by the arrow X in FIG. 9 (B).
It is rotated in the direction, and the state is as shown in FIG. In this state, the lateral moving rod 10 then moves the looper base 7
Is laterally moved in the direction of arrow 47 in FIG. 11, for example. In the case of the lateral movement, since all the passive gears 18 laterally move through the toothless portion 40 as shown in FIGS. 10 and 11, naturally, the looper 15 does not rotate at all. The lateral movement of the looper base 7 causes the looper 15 to be operated next as shown in FIG.
(The looper 15 is preloaded with a thread of a different color or type than the looper that was previously operated) is brought to the needle drop position. The position of the looper 15 in the rotation direction is held at the predetermined preparation position by the holding mechanism 13 as in the above description.

When the new looper 15 comes to the needle drop position,
Then, the rotation of the main shaft 33 causes the guide gear 38 to rotate in the arrow Y direction of FIG. When the toothed portion 39 of the guide gear 38 reaches the position shown in FIG. 9B, the passive gear 18
Engages with the toothed portion 39 to start rotation. The cam 19 rotates with the rotation of the passive gear 18. Then, the cam 19 disengages the fitting recess 20 from the rotation stop piece 42 and rides on the rotation stop piece 42 as shown in FIG. When the toothed portion 39 starts meshing with the passive gear 18, the passive gear 18 is held by the holding mechanism 13 in the same state as when it was previously disengaged from the toothed portion 39. The tooth tip of the passive gear 18 and the tooth tip of the toothed portion 39 do not collide with each other and the movement is extremely smooth. When the passive gear 18 meshes with the toothed portion 39 of the guide gear 38 as described above, the lifting device 12 causes the looper assembly 9 that has newly reached the needle drop position.
Is raised. As a result, the passive gear 18 reaches the drive gear 37 using the teeth of the guide gear 38 as guides, and the looper 15 reaches the operating position during sewing as shown in FIG.

Maintenance of various members attached to the frame 1 in the above-described sewing machine can be performed from the top plate 2 by removing the top plate 2 from the frame 1 and opening the upper surface side. In this case, even if the looper assembly 9 located at a position other than the standby position, that is, the needle drop position is accidentally touched, the removal restricting member 45 prevents the looper assembly 9 from rising, and the concave portion 20 of the cam 19 prevents the rotation stopper piece. Keeps fitted to 42. Therefore, the position of the looper 15 in the rotation direction is maintained at the preparation position.

Next, the lifting device 12 shown in FIGS.
Will be described. This lifting device 12 moves a large number of loopers laterally to change the thread and selectively positions them in the needle drop position, and the looper is set to an upper operating position for sewing operation at the needle drop position. In a multi-color sewing embroidery sewing machine which is arranged to be moved between a lower retracted position for lateral movement and a side which avoids a thread supply route which is set at a position just below the looper for raising and lowering the looper. It is intended to be able to perform smoothly from one position.

The drawings will be described below. Reference symbols A to D,
The structures represented by 1 to 45 and their actions are as described above. Next, the lifting device 12 will be described in detail. 51 is a thread 46 directly below the looper 15 at the needle drop position for each member of the lifting device 12.
Is a support frame for supporting at a side position avoiding the supply path P of the sewing machine, and in order to avoid various other mechanisms, the rear side of the path P (the side where the operator of the sewing machine is located, that is, the left side of FIG. 3). It is provided at a position (rear viewed from the rear), has a vertically long rotation stop piece 52 on the front surface, and is attached to the frame 1 with a bolt 51a.
53 is a guide rod. Reference numeral 54 is an elevating body for moving the looper assembly 9 up and down, which is mounted on the guide rod 53 so as to be vertically movable, and the fitting body 55 provided at the rear portion for preventing rotation is attached to the rotation stopping piece.
It is fitted to 52 so that it can move up and down, and the engaging piece is
An engaging portion 56 for engaging with 22 is provided. The side surface of the engagement portion 56 is formed in a U shape so that the engagement piece 22 can freely move in and out in accordance with the lateral movement of the looper base 7. The engagement portion 56 includes a push-up body 57 for raising the engagement piece 22 and a push-down body 58 for lowering the engagement piece 22. Reference numeral 59 in the pressing body 58 is a pressing piece for urging the engaging piece 22 downward, and is provided so as to be vertically movable with respect to the base material 58a of the pressing body, and is urged downward by a spring 60. is there. Next, reference numerals 61 to 63 show a structure for vertically moving the elevating body 54, and 61 is an elevating drive shaft, which is rotatably attached to the support frame 51. The shaft 61 is provided in a horizontal state across other beds, and a drive device for lifting operation is connected to one end of the shaft 61. Reference numerals 62 and 63 denote members for converting the reciprocating rotary motion of the shaft 61 into the vertical motion of the lifting / lowering body 54, 62 is a lever and 63 is a link, respectively. The link 63 is connected to the elevating body 54 approximately in the middle between the penetrating portion of the guide rod 53 and the engaging portion 56 in order to smoothly move the elevating body 54 up and down without bending.

The operation of the lifting device 12 will be described. During the sewing operation of the sewing machine, the lifting body 54 is in the raised position as shown in FIGS. 3 and 12A, and the looper 15 is in the operating position.
When the looper 15 is moved to the retracted position, the drive shaft 61 rotates counterclockwise in the figure, and the elevator 54 descends to the lowered position via the members 62 and 63 as shown in FIGS. In this downward movement, the engagement piece 22 is pushed down by the spring-biased pushing piece 59, so that the bottom surface of the cam 19 is placed at a position other than the recess 20 and the rotation-preventing piece 42.
However, even if the engaging piece 22 comes into contact with and the descent of the engaging piece 22 stops there, no trouble occurs. As described above, when the looper 15 is rotated to the preparation position, the concave portion 20 faces the rotation stopping piece 42, so that the engaging piece 22 is lowered by the pressing force of the pressing piece 59, and the concave portion 20 and the rotation stopping piece 42 are fitted. Is achieved.

Next, in FIGS. 1 to 4 and 13 to 18, E indicates a yarn cutting device. This thread cutting device E is a sewing machine in which a large number of loopers can be used interchangeably to perform various kinds of sewing while exchanging threads in various ways. Is held to prevent it from falling out of the looper, and cutting is performed in that holding state, and even if it is configured as such,
It is an object of the present invention to facilitate the work of assembling, adjusting and maintaining the yarn cutting device.

The drawings will be described below. Reference symbols A to D,
The structures of 1 to 45 and their actions are as described above. Next, the thread cutting device E will be described. The device E is provided with a cutting mechanism E1 for cutting the yarn at a position deviated laterally from the vertical movement locus so as not to hinder the vertical movement of the looper 15 and its operating mechanism E2. The cutting mechanism E1 slightly avoids the trajectory of the vertical movement of the looper 15 in order to shorten the thread remaining on the side of the cloth after cutting and the thread remaining on the looper 15 side as much as possible. It is provided as close to the looper 15 as possible. The cutting device E also includes a yarn pulling mechanism E3 for bringing the yarn between the needle hole 4 and the looper 15 to the cutting mechanism E1 and its operating mechanism E4.

First, the cutting mechanism E1 will be described. FIG.
Reference numeral 66 denotes a support for supporting each member of the cutting mechanism E1, and includes a substrate portion 66a located near the lower surface of the top plate 2 and a substrate portion 66a.
The support portion 66b for supporting the
B is bolted to the frame 1. 67 is a cutter, which is a fixed knife fixed to the substrate 66a so that the thread brought toward the cutter can be cut at the position where it was brought.
It is composed of a 68 and a movable knife 70 pivotally attached to the fixed knife 68. 68a and 70a represent the respective blades. 69 is a fixing screw and 71 is a pivotally worn pin. 72 is a movable knife 70
Is an arm for operating.

Next, the operating mechanism E2 will be described. 14
Reference numeral 74 indicates an operation shaft, which is horizontally provided so as to penetrate the frame 1 at a position immediately below the top plate 2 and is connected to a drive source (not shown). 75 is a cam for operating a knife, and a cylindrical cam is used so as to fit in a space below the top plate 2 having a small height. Reference numeral 76 is a transmission piece for transmitting the movement of the cam 75 to the movable knife 70, and has a height so that it can be positioned in a narrow space between the top plate 2 and the looper 15 which laterally moves below it, and a thread holding mechanism described later. Formed in a flat shape with a small dimensional
c is pivotally attached to the base plate portion 66a with a pin, a driven piece 76a attached to one end is fitted into the cam groove 75a of the cam 75, and the other end is connected to the arm 72 with a pin 76b. Reference numeral 77 is a member for preventing the driven piece 76a from coming off (lifting up) from the cam groove 75a, and is constituted by a pin fixed to a support 80 described later through a long hole 76d formed in the transmission piece 76.

Next, the yarn pulling mechanism E3 will be described. Reference numeral 80 denotes a support for supporting each member of the thread pulling mechanism E3, which is provided near the lower surface of the top plate 2 and bolted to the frame 1.
Reference numerals 81 and 82 denote upper and lower thread shift pieces, which are provided at the front end portion of an advancing / retreating member 85 that can be moved back and forth in the horizontal direction by guides 83 and 84 bolted to the support 80. The lower thread shift piece 82 is made of a single material together with the advancing / retreating member 85, and the upper thread shift piece 81 is welded to the advancing / retreating member 85.

The operation mechanism E4 will be described. 86 of FIG.
Is a cam for moving the thread shift pieces 81, 82 back and forth.
When assembling 2, E4, when attaching the cams 75, 86 to the operating shaft 74, without considering the positional relationship between the cams 75, 86, the relationship of the operation timing between the movable knife 70 and the thread shifters 81, 82 Is formed integrally with the cam 75 so that it is as designed. 87 is a cam
A transmission piece for transmitting the movement of 86 to the thread shift pieces 81, 82.
From the same consideration as 76, it is formed in a flat shape. Still 87a
Is a driven piece with respect to the cam groove 86a, 87b is a pin for connecting with the advancing and retracting member 85, and 87c is a pin for pivotally attaching the intermediate portion to the support 80.

Next, F in FIGS. 1 and 2 is the yarn cutting device E.
2 shows a yarn holding device provided in connection with the above. The device F is for preventing the cut yarn from falling out of the looper 15 when the yarn is cut, and will be described below with reference to FIGS. 1, 2 and 15 and 16. Reference numeral 90 in FIGS. 1 and 2 denotes thread holding means individually provided for each looper 15. Each thread holding means 90 is provided as close as possible to each looper 15 for the same purpose as the cutting mechanism E1. The thread holding means 90 has a pair of gripping pieces 92, 93. The gripping piece 92 is integrally formed with a base 91 common to all the thread holding means 90 for easy assembly. The gripping piece 93 is pivotally mounted so that the base of the gripping piece 93 can be adjusted laterally (left and right in FIG. 2) with respect to the base 91 in order to adjust the contact surfaces 92b and 93b with the gripping piece 92. I am doing it. That is, as shown in FIG. 16, the base portion 93a of the grip piece 93 is
Is loosely rotatably fitted in a holding cylinder 94, and the holding cylinder 94 is attached to a base 91 by a stopper (illustrated by a bolt) 95 having a diameter smaller than its inner diameter. 96 is a washer for preventing the gripping piece 93 from coming off. With this configuration, the position of the base portion 93a of the gripping piece 93 can be determined so that the sandwiching surfaces 93b, 92b of the gripping piece 93 and the gripping piece 92 are in close contact with each other. Then, the stopper 95 is fixed. With this configuration, the yarn can be reliably held and held at any position such as the inlet side or the inner side of the sandwiching surfaces 92b, 93b. 97 is a gripping piece
The operation piece 93 and 97a are recesses for receiving springs. Reference numeral 98 is a spring holding piece, which is attached to the base 91. 99 is a gripping piece 92,
93 is a compression coil spring for closing each other with a predetermined clamping force, and 100 is a washer for receiving a spring.

The yarn holding device F having such a structure is shown in FIG. 17A in order to reliably hold the yarn brought from the looper 15 stopped at the origin position to the yarn holding means 90 by the yarn pulling mechanism E3. As shown, the clamping surface 92b of the gripping piece 92
Of the looper 15 whose extension line 92c is at the origin position
It is attached to the looper base 7 in such a positional relationship that it passes through the position.

Next, G shown in FIGS. 1 to 4 is a releasing mechanism for releasing the yarn holding means 90 associated with the looper 15 located at the needle drop position. The mechanism G is a bracket on the frame 1
It is composed of a solenoid 102 mounted via 101. The plunger 103 of the solenoid 102 faces the operation piece 97 of the thread holding means 90. When the solenoid 102 is energized, the plunger 103 projects. Then, the operation piece 97 is pushed to open the space between the grip pieces 92 and 93.

Next, the operation of the thread cutting device E and the structure related thereto will be described. The thread cutting device E is used, for example, when the sewing using one thread is finished and the thread is changed next, and another thread is sewn. The operation will be described with reference to FIGS. 17, 18 and 19. After sewing at a normal spindle speed of about 500 rpm, the spindle speed is lowered to, for example, about 200 rpm for stopping.
When the cloth is sewn to a predetermined position, the vertical movement of the hook B is stopped and the rotation of the main shaft 33 is stopped, as indicated by reference numeral 201 in FIG. in this case,
The looper 15 is at the position of the origin in the rotation direction, for example, FIG.
The rotation of the yarn outlet 17 is stopped at the 9 o'clock position as shown in FIG. Next, using the lifting device 12, the looper assembly 9
Is lowered, and the looper 15 retracts downward from the advance / retreat path of the yarn shift pieces 81 and 82 as shown in FIGS. 4 and 17B (see reference numeral 202 in FIG. 19). Further, the release mechanism G is used to grip the gripping pieces 92, 93.
The space is opened as shown in FIG. 17C (reference numeral 20 in FIG. 19).
See 3). Next, the thread shift pieces 81 and 82 are shown in FIGS. 17 (C) and (D).
As shown in FIG. 19, the sewing thread 46 between the needle hole 4 and the thread lead-out hole 17 in the looper 15 is brought between the gripping pieces 92 and 93 and between the knives 68 and 70 (see FIG. 19). Reference numeral 204). Next, by the restoration of the release mechanism G, (E) of FIG.
As shown in (F), the space between the gripping pieces 92, 93 is closed, and the sewing thread 46
Is retained. Next, as shown in FIGS. 18G and 18H, the sewing thread 46 is cut by the operation of the movable knife 70 (see reference numeral 205 in FIG. 19). For this cutting, the cloth 104 and the gripping piece
The sewing thread 46 between 92 and 93 has one end fixed to the cloth 104 and the other end held by the holding pieces 92 and 93. That is, the suture thread 46 between them is fixed at both ends in a constant tension state. Therefore, when the knife 70 is operated, the sewing thread 46 does not get into the gap between the overlapping surfaces of the knife 68, 70 without being cut, and is reliably cut by the knife 68, 70. When the above cutting is completed, the yarn offset pieces 81, 82 are returned to their original positions (see reference numeral 206 in FIG. 19).

When the thread cutting is completed as described above, the looper 15 is exchanged as described above. When the looper 15 equipped with the thread to be used next comes to the needle drop position in the process of replacing the looper, the looper 15 is raised as shown in FIG. 3 (see reference numeral 207 in FIG. 19). When the looper replacement is completed, the vertical movement of the hook needle B is started (see reference numeral 208 in FIG. 19) and the main shaft 3
The rotation of 3 is started at a low speed, the lateral movement of the embroidery frame is also started, and the sewing of the embroidery pattern is started. In the case of this start, the tip of the suture is held by the grip pieces 92, 93. Therefore, when the hook needle B descends into the needle drop hole 16 of the looper 15 and the looper 15 rotates, the yarn supplied through the yarn lead-out hole 17 of the looper 15 is reliably caught by the hook portion of the hook needle B. Therefore, sewing is properly started without skipping. The holding of the leading end of the sewing thread is released as indicated by reference numeral 209 in FIG. 19 after the sewing at the start of sewing is ensured. Then, the rotation speed of the main shaft is also increased to bring about a normal sewing state.

Next, as another application example of the cutting device E, after finishing the sewing of embroidery at one place on the cloth,
It is used when sewing different embroidery in other places. In that case, at the time indicated by reference numeral 210 in FIG. 19, the frame is moved so that the new sewing position reaches the needle drop position. Other operations are the same as those in the above thread changing.

Next, in FIGS. 1, 3, 20, and 21, H indicates a thread entanglement prevention mechanism. This thread entanglement prevention mechanism H cuts the thread after the sewing is finished, and in the case of the cutting, in the sewing machine which is designed to cut the thread in a pre-held state so as not to drop the looper 15, An object of the present invention is to prevent the thread from being wound around the rotating looper 15 when the sewing is started again using the held thread.

The drawings will be described below. Codes A to G,
The structure of 1 to 103 and its action are as described above. Next, the thread entanglement prevention mechanism H will be described. 110 is thread holding means 9
It is a lifting member for lifting the yarn 46 held by 0 near the looper 15. Lifting height is the looper
To prevent entanglement with respect to 15, for example, the upper surface of the looper 15
It is as high as 15a. A smooth radius is formed at the corner 15b between the upper surface and the side surface of the looper 15 so that the thread slips well there, and even if the thread slightly hits the side surface of the looper 15, it is guided to the upper surface side. in case of,
The lifting height may be lower. 111 is the above-mentioned lifting member 1
An elevating mechanism for raising 10 to a position that functions as described above or lowering it so as not to interfere with thread cutting is shown. Reference numeral 112 denotes an elevating member in the mechanism 111, which is arranged along the frame 1 so as to avoid the lateral movement range of the looper base 7 so as not to interfere with the lateral movement of the looper base 7.
Guided by 3. 114 is a member for supporting the lifting member 110, and is attached to the left and right elevating members 112 in a bridge shape. 115 is a member for moving the elevating member 112 up and down,
Looper lift drive shaft 61 for simultaneous vertical movement of the looper 15
An example of the lever attached to the
a is engaged with the connecting portion 112a of the elevating member 112.

Next, the operation of the thread entanglement prevention mechanism H will be described. When the looper 15 is lowered to the retracted position as shown in FIG. 4 for the operation of the thread cutting device E, the lifting member 110 is also lowered. When the looper 15 is raised to the operating position as shown in FIG. 3 when new embroidery sewing is started thereafter, the lifting member 110 is also raised as shown in FIG.
The thread 46 whose tip is held by is lifted as shown in FIG. In this state, the operation of the looper 15 is started as shown in FIG. Therefore, the lifted thread 46 is not entangled with the rotating looper 15, and the sewing can be started smoothly.

Next, in FIGS. 3, 5, 22 to 24, J indicates a thread tension device. This thread tension device J has a plurality of loopers.
These loopers are moved by the lateral movement of the looper base 7 holding 15
By selectively locating 15 at the needle drop position, in a sewing machine that can sew on cloth by selectively using different color threads attached to each looper, no matter which looper is used for sewing, The purpose is to always be able to sew with a good thread tension from the beginning of sewing.

The drawings will be described below. Codes A to G,
The structure of 1 to 103 and its action are as described above. Next, the thread tension device J will be described. A frame 120 for holding the thread tension mechanism is attached to the looper stand 7 via the substrate 41. 120a is a window for thread insertion. 121 is each looper 1
With a plurality of thread tension mechanisms for individually adjusting the thread tension up to 5, even if the looper base 7 moves laterally, it is attached to the above le frame 120 in order to keep the positional relationship with each looper 15 constant. is there. Reference numeral 122 denotes a changing mechanism for changing the tension of each thread tension mechanism 121.

Next, the thread tension mechanism 121 will be described with reference to FIGS.
It will be explained based on. Reference numerals 123 and 124 are thread tension devices for applying a drag force to the thread 46 pulled by the hook needle B, and 125 is a tension device for applying a tension to the thread pulled out through the thread tension device 124. The thread tension device 123 is a known one that gives a certain drag force to the yarn, and 124 is a known one that can change the strength of the drag force (for example, Japanese Utility Model Publication No. 53-6611). In these, 126 and 127 are thread tension plates, 128 is a spring for pressing the thread tension plate 127 against the thread tension plate 126, and 129 is a knob for adjusting the pressing force. Reference numeral 130 in the thread tension device 124 is a member for changing the drag force, and is exemplified by a loosening bar for separating the thread tension disc 127 from the thread tension disc 126 to weaken the drag force.

Next, the tension device 125 will be described. Reference numeral 131 is a spring arm for giving an elastic pulling force to the thread, which is also called a thread take-up spring, and has a threading ring 132 at the free end. The base portion 133 of the spring arm 131 is pivotally attached to the frame 120 by a pivoting piece, for example, a pin 134 in order to change the pulling force, and is integrally provided with an operating arm 135. The operation arm 135 is projected to the back side of the frame 120 for operation by the changing mechanism 122 through the elongated hole 136. 1
37 is a member for locating the operating arm 135 on one side of the repositionable range.A spring is used to enable the operating arm 135 to move to the other side, and the frame 12
It is attached to a holding pin 138 attached to 0. Spring 137
One end 139 of this is engaged with the through hole 140 of the frame 120, and the other end 141
Is engaged with the operation arm 135 so that the operation arm 135 is pressed against the lower end 136a of the elongated hole 136 as a positioning portion thereof. Numerals 142 and 143 are thread guides for making the direction of the thread passing through the threading ring 132 appropriate for applying tension, and are attached to the frame 120.

Next, the changing mechanism 122 will be described. 145 is a change operation axis, which is provided in common to other beds,
An operating device is attached to one end. 146 is an operation member,
The operation unit 147 for operating the member 130 and the operation unit 148 for operating the operation arm 135 are provided, and only the thread tension mechanism 121 associated with the looper 15 located at the needle drop position is operated. The position is selected and attached to the operation shaft 145.

Next, the setting of the thread tension and the operation of the thread tension mechanism 121 in the above sewing will be described. When the sewing is chain stitch, the drag force and the tension applied to the thread 46 are increased. That is, the operating member 146 is placed in the position shown by the solid line in FIG. 22, the thread tension disc 127 of the thread tension regulator 124 is put in the state shown by the solid line in FIG. 22, and the spring arm 131 of the tension device 125 is put in the state shown by the solid line in FIG. When sewing is performed in this state, the tightening force of the thread with respect to the cloth during sewing is large, and it is possible to perform proper chain stitch that is tightly tightened.

On the other hand, in the case of known loop sewing (for example, Japanese Patent Laid-Open No. 4-34062), the drag force and the tension applied to the thread 46 are reduced. That is, the operating shaft 145 is turned to rotate the operating member 4
22 is placed at the position indicated by the chain double-dashed line in FIG. 22, and the thread tension disc 127 of the thread tension regulator 124 is in the state indicated by the chain double-dashed line in FIG.
The spring arm 131 of 25 is placed in the state of the chain double-dashed line in FIG. When sewing is performed in this state, the thread can be smoothly pulled up from the cloth on the needle plate 3, and loop sewing with a predetermined height can be properly performed.

Next, when the thread used for sewing is changed, since the thread tension device J is attached to the looper table 7, even if the looper table 7 moves laterally, each looper 15 and the thread tension mechanism associated with each looper 15 are moved. The positional relationship with 121 is unchanged. Therefore, even if the looper 15 is exchanged by moving the looper base 7 laterally, each looper 15
The thread between the thread and the thread tension mechanism 121 associated therewith is always kept in tension (there is no unnecessary slack). Therefore, no matter which looper 15 is used for sewing, the thread reaching the looper 15 is sewn with proper drag force by the tensioners 123, 124 and proper tension by the tension device 125 from the start of sewing. It can be performed.

3, 5 and 25, K indicates a yarn breakage detecting device. The yarn breakage detection device K selectively moves the loopers 15 to the needle drop position by the lateral movement of the looper base 7 that holds the loopers 15 so that the different color yarns are attached to the loopers. An object of the present invention is to allow a sewing machine that can be selectively used to sew a cloth, to reliably detect thread breakage during sewing, and to prevent erroneous detection during thread change.

The drawings will be described below. Reference symbols A to D,
The structures of J, 1 to 62, 121 to 148 and their actions are as described above. Next, the yarn breakage detecting device K will be described. 151
Is a main body of the detector, and for the purpose of enabling the operation with an extremely light force and simplifying the structure of the detection piece described below, a rotary operation type micro switch in which the movable portion 152 rotates is used, It is attached to the support frame 51. Reference numeral 153 is a detection piece for detecting the presence or absence of thread breakage, which is provided along the thread passage path P related to the looper at the needle drop position and freely movable in a direction crossing the path. If there is drag and tension on the and there is tension, the thread blocks movement in the above direction, and if the thread breaks and the tension disappears, push the thread and move in the above direction (no thread exists. In the case of, the urging force in the above direction is given so as to move as it is). In this example, the above-mentioned movement is made possible by attaching to the movable portion 152 of the micro switch, and the biasing force of the movable portion 152 is utilized. Figure 5
As shown in FIG.
The a is V-shaped to prevent lateral deviation from the thread. Reference numeral 154 denotes a retracting lever for deactivating the detection piece 153, and 155 is an operation piece for operating the lever 154. It is attached to lever 62.

In the thread breakage detecting device K, the detecting piece 153 contacts the thread 46 during normal sewing as shown in FIG. 25 (A), and the detector body 151 makes the thread proper. A signal indicating that there is such as a conduction signal is emitted. On the other hand, when the yarn 46 breaks, the detection piece 153 moves as shown in (B), and the detector main body 151 issues a signal indicating that the yarn breaks, for example, a non-conduction signal. When replacing the looper for thread change, when the looper elevating / lowering drive shaft 61 is rotated to lower the looper, the lever 154 is pushed by the operation piece 155 as shown in (C), and the detection piece 153 is deactivated. Therefore, even if the thread 46 does not exist in front of the detection piece 153 due to the replacement of the looper,
The detector body 151 is prevented from erroneously emitting a thread breakage signal.

Next, FIGS. 26 to 30 showing an embodiment of the present application
Will be described. In these figures, members functionally equivalent to those shown in FIGS. 1 to 25 are designated by the same reference numerals, and duplicate explanations are omitted. In FIG. 26, which schematically shows the essential parts of the sewing machine, reference numerals 160 to 172 show well-known members in this type of sewing machine, 160 is a vertically movable and rotatable needle bar, and 161 is a vertically movable needle bar. Main spindle for 162
Is a mechanism for moving the needle bar 160 up and down by receiving the turning force of the main shaft 161, 163 is a motor for rotating the main shaft, and 164 is the main shaft 16.
Encoders for detecting the rotation angle of 1 are shown respectively.
Reference numeral 165 shown in FIG. 30 denotes a hook for hooking a thread on the hook needle B, and 166 denotes an opening for introducing the thread.
Referring again to FIG. 26, 167 is a member for controlling the direction of the opening 166 of the hook 165, and for example, a pulse motor is used. Reference numeral 168 is a mechanism for rotating the needle bar 160 by receiving the turning force of the motor 167. 170 is a cloth holding frame for holding the cloth to be sewn, which is moved horizontally along the upper surface of the bed in the sewing machine. Reference numerals 171 and 172 are members for moving the cloth holding frame 170 in the horizontal direction, for example, pulse motors, the motor 171 is for moving the cloth holding frame 170 in one direction in the horizontal plane, for example, the X direction, and the motor 172 is in the horizontal plane. It is for moving in the Y direction which is orthogonal to the X direction. Next, 174 is a member for rotating the looper 15, and for example, a pulse motor is used. 175 is a motor 174
A mechanism for rotating the looper 15 at the needle drop position in response to the turning power of the needle, and 177 is a detector for detecting that the thread lead-out hole 17 in the looper 15 is at the origin position. It is composed of the detected piece 179 attached to the rotating shaft,
When the thread lead-out hole 17 reaches the origin, the detected piece 179 detects the sensor 178.
To be detected by. Next, 180 is a well-known control device for this type of sewing machine, 181 is a CPU, 182
Is an RO that stores a program for controlling the embroidery sewing machine
M and 183 are RAMs for storing the state of the sewing machine, and store the states of the respective parts of the sewing machine on the basis of signals from the encoder 164 and the sensor 178. Reference numeral 184 is a RAM for storing the data of the embroidery pattern to be sewn on the cloth.

Next, the sewing operation of the sewing machine having the above construction will be described. At the start of sewing, the end 46a of the thread 46 drawn out from the thread drawing hole 17 of the looper is held by the thread holding means 90. The thread lead-out hole 17 is located at the origin. The hook needle B is located at the top dead center. The following operation is performed under the control of the control device 180 based on the embroidery data. That is, the motor 17
1,172 is activated and the cloth is moved horizontally by one stitch. The needle bar 160 is rotated by the operation of the motor 167, and the opening 166 of the hook 165 in the hook B is directed in the direction opposite to the moving direction of the cloth (see arrow 185 in FIG. 29A). Motor 1
By the operation of 74, the thread lead-out hole 17 of the looper 15 becomes
Is brought to a start position 17a opposite to the side. The main shaft 161 is rotated by the operation of the motor 163 and the hook needle B starts to descend, and the operation of the motor 174 causes the thread lead-out hole 17 to move from the above-mentioned start position to a predetermined known position as shown by arrows 186 and 187 in FIG. The rotation is started (the angle number attached to the arrows 186, 187, 188 in FIG. 29A indicates the rotation angle of the main shaft). By each of the above-mentioned operations, the hook needle B first penetrates through the cloth, reaches the needle drop hole 16 of the looper 15, and also the thread lead-out hole.
17 rotates around the vertical movement locus of the hook needle from the start position, and the thread 46 whose thread end 46a is held by the thread holding means 90 is wound around the hook needle B. Next, in the process in which the hook needle B rises from the bottom dead center, the above-mentioned thread wound around the hook portion 165.
The thread hooked on the hook portion 165 is pulled upward from the cloth by hanging the hook needle B upward from the cloth. After the hook portion 165 is pulled out upward from the cloth as described above, the looper 15 is rotated in the return direction as shown by the arrow 188 and returns to the start position. After that, the above-described operation is repeated and the sewing of the cloth is continued. The yarn holding means 90 holds the yarn end 46a by the weight of the yarn 46 drawn out from the yarn drawing hole 17 or by the tension applied by the tension device 125 as described above.
In order to prevent the thread 46 from being pulled back inside, it is continued until at least the first time when the thread 46 is pulled up onto the cloth by the hook needle at the beginning of sewing. In order to more reliably prevent the above-mentioned pullback of the yarn, the yarn may be held until after the second pulling.

When the thread end 46a is held by the thread holding means 90 at the start of the sewing, the thread lead-out hole 17 is moved from the start position 17a to the arrow 18 as shown in FIG. 29 (A).
When rotating as indicated by 6,187, the yarn 46 between the yarn pull-out hole 17 and the gripping position of the yarn end held by the yarn holding means 90 moves left and right along the upper surface of the looper 15 as indicated by arrows 189,190. Move to. In this case, when the needle tip of the lowered hook needle B tries to pass the position where the thread moves left and right, it is assumed that the thread 46 is positioned on the vertical movement trajectory 191 of the needle tip as shown in (B). The hook needle will pierce the thread 46. This state is shown in FIGS. 27A and 27B. The horizontal axis shows the rotation angle of the main shaft, (A) shows the vertical movement of the needle tip of the hook needle B, and (B) shows the thread holding means 90.
6 shows the direction of the yarn lead-out hole 17 as seen from the holding position of the yarn end by 0 (0 is the center of the needle drop hole 16, that is, the position of the vertical movement locus of the needle tip). As shown in (A), when the needle tip passes downward on the position on the upper surface of the looper where the yarn 46 moves laterally, when the curve in the graph of (B) passes through the position of 0, the looper 15 and the yarn 46 Since the relationship with is as shown in FIG. 29 (B), the above-mentioned needle tip pierces the thread 46. Such an accident occurs, for example, when the start position 17a is in the section indicated by reference numeral 192 in FIG. 28, although it depends on the thickness of the yarn or the amount of tension applied to the yarn. Therefore, when the start position 17a is in the section 192,
Prior to rotating the thread lead-out hole 17 from the start position,
The looper 15 is rotated as indicated by an arrow 193 in FIG. 29C so that the start position 17a of the yarn drawing hole 17 deviates from the section 192. That is, the operation indicated by the arrow 194 in FIG. 27C is performed. After that, when the hook needle descends and the looper is rotated from the start position outside the section 192, when the needle tip reaches the position on the upper surface of the looper, the thread lead-out hole
The yarn 46 led out from 17 is in a state as shown in FIG. 29D, and it is possible to prevent the yarn 46 from being stuck by the needle tip as described above.

As another method, when the start position 17a is in the section 192, as shown by reference numeral 195 or reference numeral 196 in FIG. By changing it, the relationship in which the needle tip abuts on the thread 46 as described above may be eliminated.

Next, instead of the rotation control of the looper 15 by the motor 174, the rotation of the main shaft 161 causes the rotation of the looper 15 from the start position, and the thread lead-out hole 17 of the looper is hooked at the hook B. When the control provided on the side opposite to the opening 166 of the portion 165 is mechanically interlocked with the control of the direction of the opening 166, each member is mechanically operated as shown by imaginary lines 197 and 198 in FIG. It is good to link with. Since the motor 174 is unnecessary in this case, the detector 177 is attached to the motor 167.

[0053]

As described above, according to the present invention, even if the end of the thread 46 coming out of the thread lead-out hole 17 of the looper 15 at the beginning of sewing is located below the needle plate 3, the thread end Since 46a is held in advance by the thread holding means 90, the lowered hook needle B
The thread 46 can be surely wound around and pulled up, and there is an effect that sewing can be started easily.

Moreover, since the thread end is held for facilitating the start of sewing as described above, there is a small probability that the descending needle tip may pierce the thread 46. Even if it is possible,
Since the start position 17a of the rotation of the thread lead-out hole 17 is displaced and a means for changing the rotation speed is provided on the way,
There is a usefulness that the effect of only facilitating the start of the sewing can be enjoyed without causing the above danger.

[Brief description of drawings]

FIG. 1 is a plan view of a bed with a top plate removed.

FIG. 2 is a plan view of the bed with the top plate and the thread cutting device removed.

FIG. 3 is a vertical sectional view.

FIG. 4 is a partial vertical cross-sectional view of the looper assembly in a lowered state.

FIG. 5 is a front view of the looper device.

FIG. 6 is a partially cutaway perspective view showing a structure related to a drive gear and a looper.

FIG. 7 is a bottom view showing the looper holding mechanism.

FIG. 8 is a partially omitted side view showing a looper assembly and a holding mechanism thereof.

FIG. 9 is a diagram for explaining an operation sequence of looper switching.

FIG. 10 is a front view showing a relationship among a passive gear, a drive gear, and a guide gear when switching the looper.

11A and 11B are horizontal cross-sectional views showing the relationship between the passive gear and the guide gear when switching the looper.

FIG. 12 is an operation explanatory view of the looper lifting mechanism.

FIG. 13 is a perspective view of a thread cutting device.

FIG. 14 is a mechanism diagram of the thread cutting device.

FIG. 15 is an exploded perspective view of the yarn holding device.

FIG. 16 is a sectional view showing a mounting structure of a movable gripping piece base portion.

17 (A) to (D) are operation explanatory views of the yarn pulling mechanism, the yarn holding means, and the yarn cutting mechanism.

18 (E) to (H) are operation explanatory views of the yarn pulling mechanism, the yarn holding means, and the yarn cutting mechanism.

FIG. 19 is a time chart for explaining the operation.

FIG. 20 is a mechanism diagram of a thread entanglement prevention mechanism.

21 (A) and 21 (B) are operation explanatory views of the yarn entanglement prevention mechanism.

FIG. 22 is a partial vertical cross-sectional view of the thread tension mechanism.

FIG. 23 is a front view of the tension mechanism.

24A is a rear view of the tension mechanism when the tension is large, and FIG. 24B is a rear view of the tension mechanism when the tension is small.

25A to 25C are views for explaining the yarn detection device and its operation.

FIG. 26 is a perspective view showing a mechanism of a main part of the sewing machine.

FIG. 27 (A) is a graph showing the vertical movement of the needle tip,
(B), (C), and (D) are graphs showing the state of deflection to the left and right in the direction of the yarn outlet hole as seen from the holding position of the yarn end.

FIG. 28 is a plan view of the looper for showing a piercing section.

FIG. 29A to FIG. 29D are plan views for explaining rotation control of the looper.

FIG. 30 is a vertical cross-sectional view showing the relationship between the details of the hook needle and the needle plate and the looper.

[Explanation of symbols]

 A Base frame 7 Looper base 13 Holding mechanism 15 Looper 18 Passive gear 37 Drive gear 38 Guide gear

Claims (1)

[Claims] 1. A step of laterally moving the cloth each time the hook needle moves up and down, a step of repeatedly moving the hook needle up and down with the opening of the hook portion facing in a direction opposite to the moving direction of the cloth, and the hook needle lowers. In order to hook the thread on the hook in the process of rising from the dead point, a step of starting the thread lead-out hole of the looper from the start position on the opposite side of the opening and rotating around the vertical movement locus of the hook needle, and sewing At least until the thread is first pulled up by a hook needle onto the cloth at the first time, a step of grasping the end of the thread by a thread holding means arranged on the side of the looper is used. The start position is in a section in which the needle tip that is in the middle of abutting contact with the yarn that is between the yarn outlet hole that is in the middle of rotation and the position where the yarn end is gripped by the yarn holding means. , In order to eliminate the contacting relationship, A sewing method characterized in that the start position is removed from the above section in advance, or the rotation speed of the thread lead-out hole is changed midway.