JP6031380B2 - Double needle sewing machine - Google Patents

Description

  The present invention relates to a two-needle sewing machine.

2. Description of the Related Art Conventionally, a two-needle sewing machine that can perform desired sewing by switching to operate one needle bar used for sewing among two needle bars having a sewing needle at the lower end portion has been provided. It is known (for example, refer to Patent Document 1).
In this sewing machine, two types of threads having different characteristics (for example, threads of different colors and threads of different thickness) are passed through the sewing needles provided in each needle bar. Perform sewing by operating the needle bar.

  Further, the thread passed through the sewing needle of each needle bar in the sewing machine is supplied from the thread winding through the respective thread path, and a thread detection sensor for detecting the movement of the thread is disposed in each thread path. . If the thread detection sensor detects that the thread has not moved during sewing and the thread is not being supplied, and if an abnormality such as thread breakage or thread dropout is detected, the sewing machine controller will operate the sewing machine. The machine is stopped to prevent the occurrence of sewing defects.

JP 2010-12271 A

However, in the case of the above prior art, the thread detection sensor detects the movement of the thread passed through the sewing needle of one of the selected needle bars, so that the thread breakage or the thread omission on the sewing needle side of the operating needle bar is detected. It is possible to detect the occurrence of abnormalities such as. However, since it is premised that the thread passed through the sewing needle of the other needle bar when the operation is stopped is not used for sewing and does not move, the movement of the thread is detected and used to control the sewing machine. I didn't.
As a result, the thread passed through the sewing needle of the other needle bar whose operation is stopped is entangled with the operating needle bar and the thread and is sewn, resulting in poor sewing. In addition, the threading of the two threads was mistaken, resulting in a sewing failure in which sewing was performed with a thread different from the target thread.

  An object of the present invention is to provide a technique that detects the movement of a thread passed through a needle bar during operation and when operation is stopped, and enables detection of various abnormalities. More specifically, it is to provide a technique for detecting the stitching of a thread passed through a sewing needle whose operation is stopped or detecting an error in reverse of threading.

In order to solve the above problems, the invention described in claim 1
A two-needle sewing machine which is switched to driving one of the two needle bars by operation or setting and performs sewing with a sewing needle provided in the selected needle bar,
Two sensors for detecting the movement of the upper thread respectively supplied to the sewing needle of one needle bar that is selected and driven and the sewing needle of the other needle bar that is stopped and not driven;
Control means for determining the operating state of the two-needle sewing machine based on the driving state of the two needle bars and the combination of the movements of the respective upper threads detected by the two sensors;
It is provided with.

The invention according to claim 2 is the two-needle sewing machine according to claim 1,
The control means stops the two-needle sewing machine when it is determined that the operation state of the two-needle sewing machine is abnormal sewing.

The invention according to claim 3 is the double-needle sewing machine according to claim 1 or 2,
A storage means for storing a plurality of sewing abnormality patterns, each of which includes a combination of a driving state of the two needle bars and movements of the respective upper threads detected by the two sensors;
The control means determines that the operation state of the two-needle sewing machine is a sewing abnormality when the situation matches the sewing abnormality pattern stored in the storage means.

The invention according to claim 4 is the two-needle sewing machine according to claim 3,
Among the plurality of sewing abnormality patterns stored in the storage means, a setting means for selecting and setting a sewing abnormality pattern to be determined for the operation status of the two-needle sewing machine is provided.
The control means determines that the operation state of the two-needle sewing machine is a sewing abnormality when the situation matches the sewing abnormality pattern set by the setting means.

The invention according to claim 5 is the two-needle sewing machine according to any one of claims 1 to 4,
The sewing abnormality determined by the control means includes detection of stop thread stitching or reverse threading error detection.

The invention according to claim 6 is the two-needle sewing machine according to any one of claims 1 to 5,
A display unit for displaying the operation status of the two-needle sewing machine determined by the control unit is provided.

  According to the present invention, it is possible to detect the movement of the thread passed through the needle bar during operation and when the operation is stopped, and to detect various abnormalities in the two-needle sewing machine. More specifically, since it is possible to detect the sewing of the thread that has been passed through the sewing needle while the operation is stopped, or to detect an error in reverse of threading, it is possible to reduce sewing defects. It becomes.

1 is a perspective view of a sewing machine according to an embodiment of the invention. It is an expansion perspective view which shows the surface part periphery of a sewing machine. FIG. 3 is an enlarged perspective view of a periphery of a surface portion viewed from a direction different from that in FIG. 2. It is a perspective view of the internal structure stored in the inside of the surface part side front-end | tip part of a sewing machine arm part. It is a front view of a needle bar switching mechanism. It is a perspective view of a needle bar switching mechanism. It is sectional drawing which notched the two needle bars and showed the structure of the internal needle bar stop part. It is a disassembled perspective view which shows the connection state of the cam shaft of a switching drive part, and a needle bar base. It is a front view of a thread | yarn holding device. It is a perspective view of a thread | yarn holding device. It is the block diagram which showed the control system of the sewing machine. FIG. 12A shows a state where the sewing needle of one needle bar is selected as a sewing needle used for sewing, and FIG. 12B shows the sewing needle of the other needle bar used as a sewing needle for sewing. It is a front view of the needle bar switching mechanism showing a selected state. It is explanatory drawing which shows an example of the combination of the signal which a 1st thread break sensor and a 2nd thread break sensor detect. It is explanatory drawing which is an example of the combination of the signal which a 1st thread break sensor and a 2nd thread break sensor detect, and shows the table used as the reference | standard which judges whether the operation | movement condition of a sewing machine is sewing abnormality. It is a flowchart which shows the operating condition judgment process of a sewing machine. It is explanatory drawing which shows another table used as the reference | standard which judges whether the operation | movement condition of a sewing machine is sewing abnormality. It is a front view of other embodiment of the pushing protrusion of a switching lever. It is explanatory drawing which shows the modification of a switching lever. It is a perspective view of other embodiments of a thread holding device. It is the elements on larger scale of other embodiments of a thread holding device. It is the detail which looked at other embodiment of the thread | yarn holding | maintenance apparatus from the Y direction.

[Outline of Embodiment]
An embodiment of the present invention will be described with reference to FIGS.
The two-needle sewing machine 100 (hereinafter referred to as the sewing machine 100) described as the present embodiment is a so-called electronic cycle sewing machine, and has a holding frame as a cloth holding portion that holds a cloth that is a sewing object to be sewn. By moving the holding frame relative to the sewing needle, a sewing pattern based on predetermined sewing data is formed on the fabric held by the holding frame. The sewing machine 100 has two needle bars 110 and 120, and can be selectively used by switching the needle bars 110 and 120. As a result, for example, two types of upper threads U1, U2 having different characteristics such as color and thickness are inserted into the sewing needles 11, 12 provided on the needle bars 110, 120, respectively, and the sewing patterns are It can be formed from yarn.

FIG. 1 is a perspective view of the sewing machine 100 according to the present invention, FIG. 2 is an enlarged perspective view showing the periphery of the surface portion 105 of the sewing machine 100, and FIG. 3 is an enlarged perspective view of the periphery of the surface portion 105 viewed from a different direction from FIG.
Here, the vertical vertical direction is the Z-axis direction, the horizontal direction perpendicular thereto is the X-axis direction (left-right direction), and the horizontal direction perpendicular to both the Z-axis direction and the X-axis direction is the Y-axis direction (front-rear direction). It is defined as

  The sewing machine 100 includes two needle bars 110 and 120 that move up and down while holding the sewing needles 11 and 12 at their lower ends, and a needle up-and-down movement mechanism 20 that moves the sewing needle up and down using the sewing machine motor 21 as a drive source. A needle bar switching mechanism 30 that switches so that one of the two needle bars 110 and 120 performs a vertical movement operation, and upper threads U1 and U2 that are passed through the sewing needles 11 and 12, respectively. A thread tensioner 131 to 133 that applies a predetermined thread tension, a balance mechanism 14 that pulls up the upper threads U1 and U2 in the same cycle as the needle bars 110 and 120, and a sewing needle 11 or 12 that stops vertical movement. A thread holding device 60 that selectively holds the upper thread U1 or U2 passed through the sewing needle, and a single hook that entangles the lower thread (not shown) with the upper thread U1 or U2 passed through the sewing needle 11 or 12. A hook mechanism (not shown) A cloth moving mechanism 80 as a moving mechanism for holding and positioning the cloth arbitrarily along the XY plane, a sewing machine frame 101 that supports each component of the sewing machine 100, and suppressing the vertical movement of the cloth caused by a needle drop. From the intermediate presser 15, first and second thread breakage sensors 161 and 162 as first and second thread feed-out detecting means for detecting whether or not the upper threads U 1 and U 2 are fed out, and the sewing needle 11 or 12, respectively. A thread end clamping device 18 that holds the end of the suspended upper thread U1 or U2, a thread winding mechanism 19 that winds the lower thread around the bobbin, and for an operator to perform various operations on the sewing machine, input various data, and the like. An operation panel 70 and a control device 90 as control means for performing operation control of each of the above components are provided.

[Sewing frame]
As shown in FIG. 1, the sewing machine 100 includes a sewing machine frame 101 whose outer shape is substantially U-shaped when viewed from the X-axis direction. The sewing machine frame 101 includes a sewing arm portion 102 that extends above the sewing machine 100 in the Y-axis direction, a sewing bed portion 103 that extends below the sewing machine 100 and extends in the Y-axis direction, and the sewing machine arm portion 102 and the sewing bed portion 103. And a vertical body portion 104 for connecting the two.

[Cloth movement mechanism]
As shown in FIG. 1, the cloth moving mechanism 80 includes a holding frame 81 that holds an article to be sewn on the upper surface of the sewing machine bed 103, a support arm 82 that supports the holding frame 81 so as to be movable up and down, and a support arm 82. An X-axis motor 83 (see FIG. 11) that moves the holding frame 81 in the X-axis direction, and a Y-axis motor 84 (see FIG. 11) that moves the holding frame 81 in the Y-axis direction via the support arm 82. ing.
With this configuration, the cloth moving mechanism 80 can move and position the sewing object to an arbitrary position on the XY plane via the holding frame 81, and can perform needle dropping at an arbitrary position for each stitch. It is possible to form a free seam.

[Needle vertical movement mechanism]
FIG. 4 is a perspective view of the internal configuration stored inside the front end portion on the surface portion 105 side of the sewing machine arm portion 102.
As illustrated, the needle up-and-down moving mechanism 20 applies a rotational force from an upper shaft 22 that is rotatably supported in a state along the Y-axis direction in the sewing machine arm portion 102 and one end portion of the upper shaft 22. The sewing machine motor 21 (see FIG. 11), a counterweight 23 provided at the other end of the upper shaft 22, and a Y-axis around a needle bar crank (not shown) at a position eccentric from the center of rotation of the counterweight 23 A crank rod 24 having one end rotatably connected thereto, and a needle bar holder 25 for selectively holding the needle bar 110 or 120.

In the needle up-and-down movement mechanism 20, the upper shaft 22 is rotated by the output of the sewing machine motor 21, and the rotation operation is converted into the up-and-down movement operation through the counterweight 23, the needle bar crank and the crank rod 24. Then, it is possible to apply a vertical movement operation to any one of the needle bars 110 or 120 held by the needle bar holder 25.
The connection structure between the needle bar holder 25 and the needle bars 110 and 120 will be described later.

[Balance mechanism]
As shown in FIG. 4, the balance mechanism 14 can be rotated to a frame within a bell crank-shaped balance 141 in which a threading hole for inserting the upper threads U <b> 1 and U <b> 2 is formed at one end, and the sewing machine arm section 102. And a balance crank 142 pivotally supported on the shaft. The balance 141 has a base end rotatably supported by the counterweight 23, and an intermediate portion between the base end and the tip is connected to the rotation end of the balance crank 142. As a result, when the upper shaft 22 rotates, the base end portion of the balance 141 performs a revolving motion, and the distal end portion of the balance 141 moves in a predetermined vertical direction with different speeds depending on the ascending operation and the descending operation due to the connection with the balance crank 142. The operation is to be performed.

[First and second thread breakage sensors and thread tensioner]
When the surface portion 105 of the sewing machine arm portion 102 is the front surface, as shown in FIG. 2, the upper yarns U1 and U2 fed out from a thread stand (not shown) are a plurality of yarn guides 171 provided on the right side surface portion of the sewing machine arm portion 102. , 172 form respective yarn paths. In the middle of the yarn path, the first and second yarn breakage sensors 161 and 162, the thread tensioners 131 to 133, and the balance 141 are arranged in this order. It is guided to the respective sewing needles 11 and 12 through a thread holding device 60 (see FIG. 11) provided below 105.

The upper thread U1 is inserted through the first thread break sensor 161, and the upper thread U2 is inserted through the second thread break sensor 162. These thread breakage sensors 161 and 162 are provided with an optical sensor including a light source and a light receiving element at a position where the upper threads U1 and U2 pass, and the upper threads U1 and U2 are moved or detected by a detection signal from the light receiving element. It can be detected which state is stopped. The first thread break sensor 161 detects the movement of the upper thread U1, and the second thread break sensor 162 detects the movement of the upper thread U2.
For example, the upper threads U1 and U2 being sewn are repeatedly moved and stopped at a predetermined cycle so as to interlock with the vertical movement of the sewing needles 11 and 12 (needle bars 110 and 120). However, it is possible to detect that normal sewing is performed by detecting a signal that repeats an ON signal accompanying movement and an OFF signal accompanying stopping at a predetermined cycle.
That is, the thread breakage sensors 161 and 162 that detect the movement of the upper threads U1 and U2 during sewing do not detect the ON / OFF signal that repeats at a predetermined cycle, but detect only the ON signal or the OFF signal, When an ON / OFF signal other than that is detected, it is expected that a sewing abnormality has occurred.
Further, since the upper threads U1 and U2 which are not being sewn are stopped without being fed out, there is no abnormality in the upper thread by the thread break sensors 161 and 162 continuously detecting the OFF signal accompanying the stoppage. Can be detected.
That is, when the thread break sensors 161 and 162 that detect the movement of the upper threads U1 and U2 that are not being sewn detect the ON signal without detecting the continuous OFF signal, It is expected that a sewing abnormality has occurred.
The control for detecting the movements of the upper threads U1, U2 by the first thread break sensor 161 and the second thread break sensor 162 and determining the operation state of the sewing machine 100 will be described later.

The upper thread U1 is stretched over the thread tensioner 131, and the upper thread U2 is stretched over the thread tensioner 132, and individual thread tensions are applied to the upper thread U1 and U2.
Further, the thread tensioner 133 is shared by the upper threads U1 and U2, and the same thread tension is applied thereto.
The above-described balance 141 is arranged so that the tip portion protrudes outside from the right side surface portion of the sewing machine arm portion 102, and the upper yarns U1 and U2 hung on the thread tensioner 133 are placed in the respective threading holes. It is inserted.

[Needle bar switching mechanism: Overall]
FIG. 5 is a front view of the needle bar switching mechanism 30, and FIG. 6 is a perspective view. The needle bar switching mechanism 30 includes a needle bar base 31 that supports the two needle bars 110 and 120 so as to be movable up and down, and a support block 35 that supports the needle bar base 31 in the upper part in the vicinity of the surface portion 105 of the sewing machine arm portion 102. , Needle bar stop portions 32, 32 (shown in the figure) that can be switched between a holding state (vertical movement operation state) with respect to the needle bar base 31 and a holding state with respect to the needle bar holder 25 (top dead center position stop state). 7), the stop selection part 33 that performs the switching operation of the holding state for each needle bar stop part 32, 32, and the sewing needle 11 or 12 of the needle bar 110 or 120 to be used are aligned with a predetermined sewing position. And a switching drive unit (switching drive mechanism) 34 for performing the above operation.

[Needle bar switching mechanism: Needle bar base]
The needle bar base 31 is composed of an upper block 311 and a lower block 312 that are spaced apart from each other in the vertical direction, an erection portion 313 that is connected to the upper block 311 and the lower block 312, and a plate shape that extends further upward from the upper surface of the upper block 311 The support portion 314 is integrally formed.
The needle bar base 31 is supported by the support block 35 so as to be swingable about the Y axis via a support shaft 315 inserted into a support hole formed through the support portion 314 along the Y-axis direction. ing. The support block 35 is fixed to the sewing machine arm portion 102 with screws (not shown).

The upper block 311 and the lower block 312 are vertically arranged at a fixed separation distance by the installation portion 313, and the needle bar 110 and 120 are inserted into the upper block 311 and the lower block 312, respectively. The insertion holes 316 and 316 and the needle bar insertion holes 317 and 317 are formed so as to penetrate vertically.
The needle bar insertion holes 316 and 316 and the needle bar insertion holes 317 and 317 are all penetrating along the longitudinal direction of the needle bar base 31. Accordingly, when the longitudinal direction of the needle bar base 31 is set to be parallel to the Z-axis direction, the needle bar insertion holes 316 and 316 and the needle bar insertion holes 317 and 317 are also parallel to the Z-axis direction.
Furthermore, one needle bar insertion hole 316 and one needle bar insertion hole 317 are concentric and have the same diameter, and the other needle bar insertion hole 316 and the other needle bar insertion hole 317 are also concentric and have the same diameter. As such, each is formed.
The upper portion of one needle bar 110 is supported by one needle bar insertion hole 316 and the lower portion is supported by one needle bar insertion hole 317. The other needle bar 120 is supported at its upper part by the other needle bar insertion hole 316 and at its lower part by the other needle bar insertion hole 317.
The needle bar insertion holes 316 and 316 and the needle bar insertion holes 317 and 317 are all provided with sliding bearings (not shown) inside, and the needle bars 110 and 120 smoothly move up and down. It is possible to do. That is, the needle bar base 31 supports the two needle bars 110 and 120 so as to be movable up and down.

[Needle bar switching mechanism: Needle bar stop]
Both the needle bar 110 and the needle bar 120 have a hollow tubular shape, and a part of the configuration of the needle bar stop portion 32 is stored in the inside. FIG. 7 is a cross-sectional view showing the configuration of the needle bar stop portion 32 inside by cutting out the needle bars 110 and 120.
Each needle bar stop portion 32 can switch the needle bar 110, 120 between a holding state with respect to the needle bar base 31 and a holding state with respect to the needle bar holder 25. Then, a stop selection unit 33 described later performs a predetermined external operation on each needle bar stop unit 32, and one needle bar 110 is held by the needle bar holder 25 and the other needle bar 120 is a needle bar base. Switching between the first selection state held by the needle 31 and the second selection state where one needle bar 110 is held by the needle bar base 31 and the other needle bar 120 is held by the needle bar holder 25. Thus, only one of the needle bars 110 or 120 can be selectively moved up and down.

The needle bar stop portions 32 provided on each of the needle bar 110 and the needle bar 120 have the same configuration. In addition, a pin protrusion / retraction hole 111, an upper ball protrusion / retraction hole 112, and a lower ball protrusion / retraction hole 113 provided in the needle bar 110 corresponding to the needle bar stop portion 32, a pin protrusion / retraction hole 121 provided in the needle bar 120, The hole 122 and the lower ball in / out hole 123 (both described later) have the same structure.
Accordingly, only the needle bar stop 32 on the needle bar 110 side will be described, and the description of the needle bar stop 32 on the needle bar 120 side will be omitted.

  The needle bar stop 32 includes a stop bar 321 inserted into the tubular shape of the needle bar 110, a pressing spring 322 that presses the stop bar 321 upward within the needle bar 110, and an outer peripheral surface from the inside of the needle bar 110. Needle bar driving ball 323 and needle bar stop ball 324, which can be fitted into upper ball in / out hole 112 and lower ball in / out hole 113, respectively, and needle bar holding body 25, needle bar 110 is dropped. In order to prevent this, a stopper 325 fixed on the outer periphery is provided.

The stop bar 321 has a pin-shaped part 321a having a smaller diameter than the other parts of the stop bar 321 at the upper end thereof, and the pin-shaped part 321a is normally connected to the needle by pressing upward by the pressing spring 322. The pin 110 protrudes upward and outward from a pin retracting hole 111 formed on the upper end surface of the rod 110.
Further, the stop bar 321 has first and second groove cam portions 321b and 321c formed at two locations on the upper and lower sides. These groove cam portions 321b and 321c are formed with a smaller diameter than other portions of the stop bar 321, and the first groove cam portion 321b located on the upper side has a conical taper formed at the inner lower portion of the groove. The second groove cam portion 321c located on the lower side is formed with a conical taper at the inner upper portion of the groove.

A needle bar drive ball 323 and a needle bar stop ball 324 are accommodated in spaces formed between the inner wall surface of the needle bar 110 and the groove cam portions 321b and 321c, respectively.
Further, an upper ball retracting hole 112 penetrating from the inside to the outside is formed at a position where the needle bar driving ball 323 accommodated in the first groove cam portion 321b of the needle bar 110 is faced. At a position where the needle bar stop ball 324 accommodated in the second groove cam portion 321c faces, a lower ball intrusion hole 113 penetrating from the inside to the outside is formed.
The upper ball retracting hole 112 has a larger diameter than the needle bar driving ball 323 on the inner side of the needle bar 110, and has a diameter slightly smaller than that of the needle bar driving ball 323 on the outer peripheral surface of the needle bar 110. It has become. Further, the inner diameter of the lower ball retracting hole 113 and the needle bar stop ball 324 have the same relationship.

When the pin-shaped portion 321a of the stop bar 321 is in a state where it protrudes to the maximum extent (hereinafter, simply referred to as “projection state”), the first groove cam portion 321b is slightly above the upper ball retracting hole 112. The position is set so that the second groove cam portion 321c is positioned with respect to the lower ball retracting hole 113. In this state, the needle bar drive ball 323 is partially protruded from the upper ball retracting hole 112, and the needle bar stop ball 324 is retracted inward from the lower ball retracting hole 113 (the needle bar of FIG. 7). 120).
In addition, when the pin-shaped portion 321a of the stop bar 321 is pushed in (for example, about half to the full length of the protruding shape of the pin-shaped portion 321a: hereinafter referred to as “push-in state”), The groove cam portion 321b of the second ball cam portion 321b matches, and the second groove cam portion 321c is located slightly below the lower ball retracting hole 113. In this state, the needle bar drive ball 323 is retracted inward from the upper ball in / out hole 112, and the needle bar stop ball 324 is partially protruded from the lower ball in / out hole 113 (the needle bar in FIG. 7). 110).

Then, when the needle bar 110 is located at the top dead center height and the needle bar holder 25 is also at the top dead center position, if the pin-shaped portion 321a of the stop bar 321 is in the protruding state, the needle bar 110 is moved from the upper ball retracting hole 112. The needle bar hug 25 can be sandwiched up and down by the needle bar drive ball 323 and the stopper 325 protruding from the part. Accordingly, the needle bar 110 can be held with respect to the needle bar holder 25, and the vertical movement operation from the needle vertical movement mechanism 20 can be transmitted to the needle bar 110.
Further, a ball stopper 326 is provided on the upper surface of the lower block 312 of the needle bar base 31, and a structure that prevents the needle bar 110 from descending with respect to the needle bar base 31 when a protrusion is present on the outer peripheral surface of the needle bar 110. It has become. However, when the pin-shaped portion 321a is in the projecting state, the needle bar stop ball 324 is retracted to the inside of the lower ball retracting hole 113, so that the vertical movement of the needle bar 110 with respect to the needle bar base 31 is not restricted.
Accordingly, the needle bar 110 is in an up / down motion state.

On the other hand, when the needle bar 110 is positioned at the top dead center height and the needle bar holder 25 is also at the top dead center position, if the pin-shaped portion 321a of the stop bar 321 is pushed in, the needle from the upper ball retracting hole 112 Since the bar drive ball 323 moves backward, the holding state of the needle bar 110 with respect to the needle bar holder 25 is released.
Further, since the needle bar stop ball 324 partially protrudes from the lower ball retracting hole 113 when the pin-shaped portion 321a is in the pushed state, the needle stopper 110 is prevented from descending with respect to the needle bar base 31 by the ball stopper 326. Further, the above-described stopper 325 is disposed so as to contact or be close to the lower surface of the upper block 311 of the needle bar base 31 when the needle bar 110 is located at the top dead center. The needle bar 110 is also prevented from moving above the top dead center position.
Therefore, the needle bar 110 is in a holding state with respect to the needle bar base 31.

  Thus, when the needle bar 110 is at the top dead center, the needle bar stop part 32 holds the needle bar 110 with respect to the needle bar hug 25 by pushing the pin-shaped part 321a of the stop bar 321. It is possible to switch from the (vertical movement operation state) to the holding state (top dead center position stop state) with respect to the needle bar base 31. Further, if the pushing operation of the pin-shaped portion 321a is released, the pressing spring 322 can automatically return the holding state with respect to the needle bar base 31 to the holding state with respect to the needle bar holder 25.

[Needle bar switching mechanism: switching drive unit]
In the needle bar switching mechanism 30, the needle 11 or 12 can be selected by swinging the needle bar base 31 about the support shaft 315 around the Y axis.
Therefore, in the switching drive unit 34, the tip of the sewing needle 11 and the top dead center when positioned vertically between the top dead center and the bottom dead center in a perpendicular line perpendicular to the center line of the support shaft 315 and lowered downward. And the needle bar base 31 are swung so that the tip ends of the sewing needles 12 positioned in the middle of the bottom dead center have the same inclination angles. In addition, the state in which the tip of the sewing needle 11 and the tip of the sewing needle 12 are at an inclination angle that coincides with the perpendicular line is referred to as “the sewing needle 11 or the sewing needle 12 is in the sewing position”. Each sewing needle 11, 12 forms a seam by sharing one intermediate presser 15 and one hook.

  As shown in FIGS. 4 to 6, the switching drive unit (switching drive mechanism) 34 includes an air cylinder 341 serving as a drive source for the swinging motion of the needle bar base 31, and one rotating arm as a plunger of the air cylinder 341. , A link body 343 having one end connected to the other rotating arm of the bell crank 342, an input arm 346 having one end connected to the link body 343, and one end to the input arm 346. A cam shaft 344 having a fixed portion connected thereto, an eccentric cam 344a provided on the other end side of the cam shaft, and a square piece 347 (shown in FIG. 8) to which the eccentric cam 344a is attached.

  When the plunger of the air cylinder 341 moves forward and backward, the bell crank 342 rotates and the link body 343 moves forward and backward. The other end portion of the link body 343 is connected to the rotation end portion of the input arm 346, and the rotation operation can be imparted to the input arm 346 by the operation of the air cylinder 341. Note that the air cylinder (second actuator) 341 is swingably supported by the sewing machine frame 101, and the displacement in the X-axis direction generated at the connecting portion with the bell crank 342 is allowed by swinging in the forward / backward movement of the plunger. It is possible to do.

  The cam shaft 344 fixedly connected to the input arm 346 includes a circular eccentric cam 344a that is eccentric with respect to the rotation center. The eccentric cam 344a is inserted into the hole 347a of the square piece 347 as shown in FIG. The square piece 347 is fitted in a fitting groove 318 formed in the lower block 312 of the needle bar base 31. The fitting groove 318 is formed in the lower part of the needle bar base 31 along the longitudinal direction (parallel to the swinging radial direction of the needle bar base 31). Accordingly, when the camshaft 344 rotates via the input arm 346 by driving the air cylinder 341, the square piece 347 moves in the left-right direction (X-axis direction), and the needle bar base 31 can be swung. is there.

  Each configuration of the switching drive unit 34 is such that the sewing needle 11 is in the sewing position when the plunger of the air cylinder 341 is in the forward position, and the sewing needle 12 is in the state where the plunger of the air cylinder 341 is in the retracted position. The dimension of each part is designed so that it will be in the state in a sewing position. In addition, either of the configurations of the needle bar base 31 and the switching drive unit 34 is provided with two stoppers so that the sewing needle 11 can be accurately stopped at the position where the sewing needle 11 is at the sewing position and the position where the sewing needle 12 is at the sewing position. Also good. In that case, the position of each stopper may be adjustable, and the positions of the sewing needles 11 and 12 may be adjustable.

[Needle bar switching mechanism: Stop selection section]
The stop selection unit (stop selection mechanism) 33 performs the first operation by pushing the needle bar stop units 32 and 32 of the needle bar 110 and the needle bar 120 with respect to the respective pin-shaped portions 321a and 321a. The selected state (one needle bar 110 is held by the needle bar holder 25 and the other needle bar 120 is held by the needle bar base 31) and the second selected state (one needle bar 110 is the needle bar base 31). And the other needle bar 120 is held by the needle bar holder 25).

  As shown in FIGS. 5 to 7, the stop selection unit 33 includes an air cylinder (actuator) 331 serving as a drive source for the state switching operation of the needle bar 110 and the needle bar 120, and an input arm 332 a on the plunger of the air cylinder 331. And a switching lever (switching member) 332 connected thereto.

The support block 35 is fixed to the sewing machine arm portion 102. The support shaft 315 is fixed to the support block 35. The support shaft 315 supports the needle bar base 31 and the switching lever 332 so as to be rotatable about the Y axis. The switching lever 332 is disposed close to the upper side of the two needle bars 110 and 120.
The switching lever 332 includes an input arm 332a extending in the radial direction around the support shaft 315, and two push-in protrusions 332b and 332c, both extending in a radial direction different from the input arm 332a. Yes.
The switching lever 332 is rotatably supported by the support shaft 315 with the input arm 332a facing upward. The input arm 332 a is connected to the plunger of the air cylinder 331 supported by the support block 35. The air cylinder 331 is supported by the support block 35 so as to be able to swing, and allows the displacement in the Z-axis direction that occurs at the connecting portion of the switching lever 332 to the input arm 332a by swinging when the plunger moves forward and backward. It is possible.

Further, the two pushing projections 332b and 332c are generally directed downward, and the one pushing projection 332b is located at a position facing the pin-shaped portion 321a projecting from the needle bar 110 by the backward movement of the plunger of the air cylinder 331. The other push-in projection 332c is switched to a position facing the pin-shaped portion 321a protruding from the needle bar 120 by the forward movement of the plunger of the air cylinder 331.
Further, the protruding lengths of the push-in protrusions 332b and 332c are such that when the needle bars 110 and 120 are raised to the top dead center height, the pin-shaped portions 321a and 321a hold the needle bars 110 and 120, respectively. The length is set such that the push-in is performed with the push-in amount capable of switching the state.

The swinging operation of the needle bar base 31 by the switching drive unit 34 and the switching operation to the first or second selection state by the stop selection unit 33 are performed in conjunction with each other.
That is, when the needle bar 110, 120 is switched to the first selection state (the state in which the needle bar 110 moves up and down) by the switching lever 332 of the stop selection unit 33, the switching drive unit 34 is connected to the needle bar base 31. The needle bar 110 is swung so that it becomes the sewing position, and the needle bar 110, 120 is brought into the second selected state (the needle bar 120 moves up and down) by the switching lever 332 of the stop selection unit 33. When switching, the switching drive unit 34 swings so that the needle bar 120 of the needle bar base 31 is in the sewing position.

Therefore, when the respective pushing protrusions 332b and 332c of the switching lever 332 are rotated to positions facing the pin-shaped portions 321a and 321a of the needle bars 110 and 120, the swing angle of the needle bar base 31 is taken into consideration. Therefore, the dimensions of the input arm 332a and the push-in protrusions 332b and 332c of the switching lever 332 and the stroke of the air cylinder 331 are set so as to be in an appropriate position.
Further, two stoppers may be provided so that the pushing protrusions 332b and 332c of the switching lever 332 are accurately stopped at an appropriate position when the air cylinder 331 is operated. In that case, the positions of the stoppers may be adjustable, and the stop positions of the push-in protrusions 332b and 332c may be adjustable.

[Thread end clamp device]
The thread end clamping device 18 has a wiper capable of removing the upper thread end hanging from the needle holes of the sewing needles 11 and 12, a suction port capable of sucking the upper thread end guided by the wiper, and a guide guided to the suction port. A ball that clamps the yarn end, an air cylinder 181 (shown in FIG. 11) that moves the ball toward the suction port, and the like are provided.
At the beginning of sewing, after passing the upper thread through the left and right sewing needles 11 and 12, the operator operates the operation panel (not shown) to drive the wiper and suck the left and right upper threads U1 and U2. Guide to the mouth. At the start of sewing, the left and right upper thread ends are sucked into the suction port. However, since the suction force to the thread is weak, when one needle moves up and down to form a seam, the suction to one thread is released. When several stitches are formed, the ball moves and pinches the upper thread of the other needle that does not form the seam, so that the upper thread of the other needle is not caught and sewn. After the thread trimming, the wiper is automatically driven to suck the upper thread end.

[Thread holding device]
9 is a front view of the yarn holding device 60, and FIG. 10 is a perspective view. The thread holding device 60 holds the upper thread U1 or U2 inserted through the sewing needle 11 or 12 that is not selected as a sewing needle for sewing so that the upper thread U1 or U2 is not pulled out from the sewing needle 11 or 12 by the lifting operation of the balance 141. It is for doing.
The thread holding device 60 includes a movable holding member 61 provided at a front lower end of the needle bar base 31 and two opposing parts 621 that are close to and opposed to the movable holding member 61 on both sides in the swinging direction of the needle bar base 31. , 622 and a fixed holding member 62.

The movable holding member 61 is fixed to the lower part of the needle bar base 31 (on the side of the sewing needles 11 and 12 with respect to the support shaft 315), and a thread holding part 611 formed by bending forward is formed at the lower end part thereof. Has been. The thread holding portion 611 has a rectangular flat plate shape along the XY plane, and both left and right side edge portions 611a and 611b are formed in parallel to the Y-axis direction.
The fixed holding member 62 is fixed to the frame of the surface portion 105, and the facing portions 621 and 622 are all disposed so as to be parallel to the YZ plane.

The movable holding member 61 is arranged in a state where the thread holding portion 611 is loosely inserted between the facing portions 621 and 622 of the fixed holding member 62. One opposing portion 621 of the fixed holding member 62 is closely opposed to one side edge 611a of the yarn holding portion 611 on the left side in the X-axis direction, and is fixedly held to the other side edge 611b of the yarn holding portion 611. The other facing portion 622 of the member 62 is closely opposed on the right side in the X-axis direction.
Further, a gap between one side edge portion 611a of the thread holding portion 611 and one facing portion 621 of the fixed holding member 62 serves as a first threading portion for inserting the upper thread U1 inserted through the sewing needle 11. The upper thread U1 on the way from the balance 141 to the sewing needle 11 is inserted.
Further, the gap between the other side edge 611b of the thread holding portion 611 and the other facing portion 622 of the fixed holding member 62 serves as a second threading portion for inserting the upper thread U2 that is inserted into the sewing needle 12. The upper thread U2 on the way from the balance 141 to the sewing needle 12 is inserted.

The movable holding member 61 is mounted on a needle bar base 31 that reciprocally swings along the X-axis direction. When the needle bar base 31 selects the sewing needles 11 and 12 to be sewn, the needle bar switching mechanism 30 is provided. The switching drive unit 34 gives a swinging motion.
When the sewing needle 11 is selected, the switching drive portion 34 swings the lower end portion of the needle bar base 31 to the right, so that the other side edge portion 611b of the thread holding portion 611 of the movable holding member 61 is fixed to the fixed holding member. 62 contacts the other facing portion 622 side. As a result, the upper thread U2 on the side of the sewing needle 12 that is not used is held between them, and it is possible to prevent the upper thread U2 from being pulled out of the sewing needle 12 against the lifting operation of the balance 141.
When the sewing needle 12 is selected, the switching drive unit 34 swings the lower end portion of the needle bar base 31 to the left, so that one side edge 611a of the thread holding portion 611 of the movable holding member 61 is fixed to the fixed holding member. 62 contacts one of the opposing portions 621 side. As a result, the upper thread U1 on the side of the sewing needle 11 that is not used is held between them, and it is possible to prevent the upper thread U1 from being pulled out of the sewing needle 11 against the lifting operation of the balance 141.

[Center press]
The intermediate presser 15 is provided with a frame-like portion in which the sewing needle 11 or 12 selected at the time of sewing can be loosely inserted, and the frame-like portion moves up and down with a small stroke in synchronization with the sewing needle 11 or 12. This is a member for restraining the fabric from swinging up and down greatly due to friction with the sewing needle 11 or 12, and for more reliably pulling out the sewing needle 11 or 12 from the fabric.
The intermediate presser 15 is supported by an intermediate presser drive mechanism (not shown) provided in the sewing machine arm 102, and the intermediate presser drive mechanism obtains power from the upper shaft 22 and imparts an up / down motion operation of the intermediate presser 15. It is carried out.

[Thread winding mechanism]
The thread winding mechanism 19 (see FIG. 2) is a mechanism for winding the bobbin thread around a bobbin provided inside the hook. The bobbin winding mechanism 19 includes a bobbin holding base 19a for setting a bobbin, and a power transmission mechanism that obtains power from the upper shaft 22 and applies a rotating operation to the bobbin holding base 19a. The power transmission mechanism includes a detection lever 19b that detects that a bobbin is set on the bobbin holding base 19a. When the bobbin is detected by the detection lever 19b, power is transmitted from the upper shaft 22 to the bobbin holding base 19a. It is like that. Further, the detection lever 19b is configured to cut off power transmission from the upper shaft 22 to the bobbin holding base 19a when a predetermined amount of lower thread is wound around the bobbin.

[control panel]
The operation panel 70 (see FIG. 11) includes a touch panel 71 and a liquid crystal panel 72. The operation panel 70 and the sewing machine control device 90 are connected by a wired or wireless line.
The touch panel 71 is disposed on the display screen of the liquid crystal panel 72 and has a function of detecting a contact position of the liquid crystal panel 72 with respect to the display screen.
The liquid crystal panel 72 is a display unit having a function of displaying an operation key group having various keys and buttons, various sewing data, and various display screens.
That is, the operation panel 70 touches an operation key group displayed on the liquid crystal panel 72, and the touch panel 71 has a position reading principle such as an electromagnetic induction type, a magnetostriction type, a capacitance type, or a pressure sensitive type. Is a device that detects a touch-instructed position, performs various operations of the sewing machine, inputs various data, and displays various display screens according to the detected position.
For example, the operation panel 70 is one of setting means for selecting and setting a sewing abnormality pattern which is a judgment target of the operation status of the sewing machine 100 among a plurality of sewing abnormality patterns stored in a storage means (data memory 94) described later. It functions as a part.

[Sewing machine control system: control device]
FIG. 11 is a block diagram showing a control system of the sewing machine 100. The sewing machine 100 includes a control device 90 as a control unit for controlling the operation of each unit and each member described above. The control device 90 includes a ROM 92 that stores a program for performing operation control in sewing, a RAM 93 that is a work area for arithmetic processing, and nonvolatile data as storage means that stores various data such as sewing data. A memory 94 and a CPU 91 for executing a program in the ROM 92 are provided.

The CPU 91 is connected to the sewing machine motor drive circuit 21a, the X-axis motor drive circuit 83a, and the Y-axis motor drive circuit 84a through an interface (not shown), and through these, the sewing machine motor 21, the X-axis motor 83, and the Y-axis motor. 84 is controlled.
The sewing machine motor 21 is a servo motor provided with an encoder (not shown), and the detected angle is output to the CPU 91.
The X-axis motor 83 and the Y-axis motor 84 are stepping motors, and origin search means (not shown) is connected to the CPU, and the CPU 91 can recognize the origin positions of the motors 83 and 84 from the output. .
Further, the CPU 91, via an interface (not shown), the air cylinder 331 of the stop selection unit 33 of the needle bar switching mechanism 30, the air cylinder 341 of the switching drive unit 34 of the needle bar switching mechanism 30, and the air cylinder of the yarn end clamping device 18. 181a is connected to drive circuits 333a, 347a, 182a for controlling electromagnetic valves 333, 347, 182 for operating each of the 181.

Further, only the thread tensioner 133 of the above-described thread tensioners 131 to 133 has a built-in solenoid, and the thread tension can be arbitrarily controlled by the control of the control device 90. Accordingly, the drive circuit 133a of the thread tensioner 133 is also connected to the CPU 91 via an interface (not shown).
Further, the first and second thread breakage sensors 161 and 162 for detecting the state of the upper threads U1 and U2 in other cases during sewing are connected to the CPU 91 via a sensor driver 160a.

In the sewing data stored in the data memory 94, the cloth feed amounts of the X-axis motor 83 and the Y-axis motor 84 for moving the cloth to the needle drop position of each stitch for sewing a predetermined sewing pattern are determined. The cloth feed data, the selection sewing needle data that determines which sewing needle 11 or 12 is used, the thread tension data that determines the thread tension, and the like are recorded. Every time, the setting contents of the sewing data are read, and the operation control of each configuration of the sewing machine is executed.
For example, when the CPU 91 reads the cloth feed data for each needle, the X-axis motor 83 and the Y-axis motor 84 are driven at a predetermined upper axis angle to move the cloth to a target needle drop position. .
Further, when the CPU 91 reads the yarn tension data, the built-in solenoid of the yarn tensioner 133 is driven at a predetermined upper axis angle to drive the target yarn tension.

  Note that the data memory 94 includes a plurality of sewing items including combinations of driving states of the two needle bars 110 and 120 and movements of the upper threads U1 and U2 detected by the two thread breakage sensors 161 and 162, respectively. Data on abnormal patterns is stored. This sewing abnormality pattern will be described later.

Further, when the CPU 91 reads the selected sewing needle data during the sewing, “sewing machine motor stop” → “upper and lower thread cutting” → “switching of used sewing needle” is executed in order.
That is, in “stop the sewing machine motor”, the CPU 91 controls to stop the sewing machine motor 21 at a predetermined upper axis angle.
In “upper and lower thread cutting”, the CPU 91 controls a thread trimming motor (not shown) to perform thread trimming of the upper thread and the lower thread that have been sewn.
Further, in the “switching of sewing needles to be used”, the CPU 91 operates the air cylinder 331 of the stop selection unit 33 and the air cylinder 341 of the switching drive unit 34 of the needle bar switching mechanism 30 to switch the switching lever 332 and the needle bar base. 31 is swung.
Thereby, the pushing position of the pin-shaped part 321a which protrudes from the upper end of the needle bar 110 or 120 by the switching lever 332 is switched. Further, the needle bar base 31 swings and the sewing needle 11 or 12 is positioned at the sewing position.

[Switching operation of sewing needle to be used]
The above-described “switching the sewing needle to be used” operation will be described in more detail based on the operation explanatory diagram of FIG.
When the CPU 91 of the control device 90 reads the selected sewing needle data from the sewing data in the middle of sewing to form the sewing pattern, for example, the CPU 91 switches from the sewing needle that has been sewn so far to another sewing needle. Here, a case where the sewing needle 12 is switched to the sewing needle 11 is illustrated.
First, the CPU 91 stops the sewing machine motor 21 so as to stop the rotation of the upper shaft 22 at an upper stop position that is a predetermined upper shaft stop angle. For example, the upper axis angle of the upper stop position is the top dead center of the balance 141 (for example, when the needle bar top dead center is 0 °, the upper axis angle is in the range of 30 to 50 °). At this time, since the sewing machine motor 21 is stopped at a position that has passed the needle bar top dead center, the needle bar 120 that holds the sewing needle 12 that has been sewn so far has a lowering operation somewhat from the top dead center position. . Although FIG. 12A shows a state where the needle bar 120 is greatly lowered, the height difference between the needle bar 110 and the needle bar 120 stopped at the upper stop position is the case of FIG. 12A. Smaller than.

Then, the thread trimming motor (not shown) is controlled in the stopped state to perform thread trimming of the upper thread and the lower thread that have been sewn. Next, the wiper of the thread end clamping device 18 is driven, and the upper thread ends of the left and right sewing needles 11 and 12 are guided to the suction port and sucked.
After that, as shown in FIG. 12B, the air cylinder 341 of the switching drive unit 34 of the needle bar switching mechanism 30 is operated to swing the needle bar base 31 in the direction in which the lower end part is directed rightward. As a result, the sewing needle 11 is switched to the sewing position after the sewing needle 12 is disengaged from the sewing position (the position immediately below the support shaft 315).

In addition, the air cylinder 331 of the stop selection unit 33 is operated so that the pushing protrusion 332c of the switching lever 332 is positioned so as to face the pin-shaped portion 321a of the needle bar 120 of the needle bar base 31 after swinging. 332 is rotated.
At this time, since the needle bar 12 is somewhat lowered, the switching lever 332 can be rotated without causing interference between the push-in protrusion 332 c and the pin-shaped portion 321 a of the needle bar 120.

  As the switching lever 332 rotates, the push-in protrusion 332b deviates from the position facing the pin-shaped portion 321a of the needle bar 110, so that the stop bar 321 inside the needle bar 110 is pushed upward by the pressing spring 322. Arise. As a result, the groove cam portion 321c moves upward, and the needle bar stop ball 324 retracts inward in the lower ball retracting hole 113 (see FIG. 7). Accordingly, the state where the needle bar 110 is held by the needle bar base 31 is released. Since the upper shaft 22 is stopped at a position where the upper shaft angle has passed the needle bar top dead center, the needle bar holder 25 is in a somewhat lowered state. The needle bar drive ball 323 cannot protrude outward from the upper ball retracting hole 112, and the needle bar 110 is not held by the needle bar holder 25.

Then, the CPU 91 controls the sewing machine motor 21 to be driven in reverse rotation so as to return from the upper stop position (balance top dead center) to the needle bar top dead center. As a result, the needle bar 120 and the needle bar holder 25 are raised, and the pin-shaped portion 321a of the needle bar 120 comes into contact with the pushing protrusion 332c of the switching lever 332 and is pushed downward. Therefore, the groove cam portion 321 b of the stop bar 321 inside the needle bar 120 is lowered, and the needle bar drive ball 323 is retracted inward from the upper ball retracting hole 112. Further, the groove cam portion 321c is also lowered, and the needle bar stop ball 324 protrudes from the lower ball in / out hole 113. Accordingly, the needle bar 120 is switched to the state in which the needle bar holder 25 is released from the holding state and is held by the needle bar base 31.
On the other hand, in the needle bar 110, the needle bar driving ball 323 protrudes from the upper ball in / out hole 112 and is held by the needle bar holder 25.

When the needle bar base 31 is rotated from the state shown in FIG. 12A to the state shown in FIG. 12B, in the thread holding device 60, the movable holding member 61 moves to the right. The upper thread U1 held between the left side edge portion 611a and the facing portion 621 is released. Further, the right side edge portion 611b of the yarn holding portion 611 of the movable holding member 61 contacts the facing portion 622, and holds the upper yarn U2 therebetween.
Thereafter, the sewing machine motor 21 resumes rotation in the normal rotation direction, and the needle drop by the sewing needle 11 is performed, but the upper thread U2 of the sewing needle 12 is connected to the side edge 611b and the opposing portion 622 of the thread holding portion 611. Therefore, even if the balance 141 is pulled upward, the pull-out from the sewing needle 12 is prevented. In addition, when several stitches are formed after the start of sewing, the ball of the thread end clamping device 18 moves, and the upper thread of the sewing needle 12 that does not form the seam is clamped. Is prevented from being caught and sewn.

  Note that the operation input for pressing the “selected sewing needle” key (not shown) on the operation panel 70 is not limited to performing “switching of the sewing needle to be used” with the reading of the selected sewing needle data in the sewing data. It is also possible to perform “switching of the sewing needle to be used” as described above and perform sewing with the upper threads U1 and U2 on the desired sewing needles 11 and 12 (needle bars 110 and 120) side. .

[Determination of operating status of double-needle sewing machine]
Next, the operation status determination of the sewing machine using the first thread break sensor 161 and the second thread break sensor 162 in the sewing machine 100 will be described. The first thread break sensor 161 and the second thread break sensor 162 are collectively referred to as two sensors that detect the movement of the upper thread.
Here, a case where one needle bar 110 is selected and sewing is performed with the sewing needle 11 provided in the needle bar 110 will be described as an example. In addition, since it is the same when performing sewing with the sewing needle 12 provided in the other needle bar 120, the description thereof is omitted.

For example, when switching to driving one of the needle bars 110 and performing sewing with the sewing needle 11 of the selected needle bar 110, if normal sewing is performed without sewing abnormality, “No” in FIG. .1 "portion, the first thread break sensor 161 detects a signal that repeats an ON signal associated with the movement of the upper thread U1 and an OFF signal associated with the stop in a predetermined cycle, and a second thread break sensor 162 is disposed. However, the OFF signal accompanying the stop of the upper thread U2 is continuously detected.
That is, when performing sewing using the needle 11 of the needle bar 110, the first thread break sensor 161 and the second thread break sensor 162 detect the signals shown in the “No. 1” portion of FIG. Thus, it is possible to detect that normal sewing is performed.

Further, when switching to the driving of one needle bar 110 and performing sewing with the sewing needle 11 of the selected needle bar 110, the upper thread U2 that is not being sewn is drawn into the upper thread U1 that is being sewn and sewn. When an abnormal sewing occurs, as shown in “No. 3” in FIG. 13, the first thread break sensor 161 generates an ON signal accompanying the movement of the upper thread U1 and an OFF signal accompanying the stop for a predetermined period. The second thread break sensor 162 detects the ON / OFF signal of the upper thread U2 fed out in a cycle synchronized with the upper thread U1 being sewn.
That is, when performing sewing using the sewing needle 11 of the needle bar 110, the first thread break sensor 161 and the second thread break sensor 162 detect the signals shown in the “No. 3” portion of FIG. Thus, it is possible to detect a sewing abnormality in which the upper thread U2 that is not being sewn is sewn.

Further, when switching to the driving of one needle bar 110 and performing sewing with the sewing needle 11 of the selected needle bar 110, when a sewing abnormality occurs in which the upper thread U1 being sewn is broken, FIG. As shown in the “No. 2” portion, the first thread break sensor 161 continuously detects the OFF signal due to the fact that the upper thread U1 does not move, and the second thread break sensor 162 detects the upper thread U2. The OFF signal that accompanies stoppage is continuously detected.
That is, when the needle bar 110 is sewn using the sewing needle 11, the first thread breakage sensor 161 and the second thread breakage sensor 162 detect the signals shown in the “No. 2” portion of FIG. Thus, it is possible to detect a sewing abnormality in which the upper thread U1 being sewn is broken.

In addition, when switching to the driving of one needle bar 110 and performing sewing with the sewing needle 11 of the selected needle bar 110, a sewing abnormality occurs in which the upper thread U2 that is not being sewn is wound around the balance 141. 13, the first thread break sensor 161 detects a signal that repeats an ON signal accompanying the movement of the upper thread U1 and an OFF signal accompanying the stop at a predetermined period, The second thread break sensor 162 detects an ON signal for continuously feeding the upper thread U2 and an ON / OFF signal that is not in a predetermined cycle.
That is, when performing sewing using the needle 11 of the needle bar 110, the first thread break sensor 161 and the second thread break sensor 162 detect the signals shown in the “No. 4” portion of FIG. Thus, it is possible to detect a sewing abnormality in which the upper thread U2 not being sewn is wound around the balance 141 and the upper thread U2 is fed out.

When one needle bar 110 is selected and sewing is performed with the sewing needle 11 provided in the needle bar 110, the combinations of movements of the upper threads U1 and U2 detected by the two thread breakage sensors 161 and 162 are respectively: No. above. 1-No. It is not limited to 4. For example, there are 10 combinations of patterns as shown in the table of FIG. However, of these 10 patterns, No. 7-No. 9 is a combination pattern of the movements of the upper threads U1 and U2 relating to the abnormality detection when the lower thread is wound around the bobbin by the thread winding mechanism 19 instead of the sewing with the sewing needle 11.
In addition, No. shown in the table of FIG. 1-No. Reference numeral 4 denotes a pattern corresponding to “No. 1” to “No. 4” in FIG.

The table shown in FIG. 14 shows combinations of signals detected by the two thread breakage sensors 161 and 162, which are combinations of movements of the upper threads U1 and U2 detected by the two thread breakage sensors 161 and 162, respectively. The operating state (abnormality detection) of the sewing machine that can be determined based on the combination is exemplified.
For example, when the first thread break sensor 161 detects an ON / OFF signal of a predetermined cycle and the second thread break sensor 162 detects an OFF signal, it is detected that normal sewing is performed. (No. 1) (normal sewing).
The first thread break sensor 161 detects an OFF signal, and the second thread break sensor 162 detects an OFF signal, thereby detecting a sewing abnormality in which the upper thread U1 being sewn is broken. (No. 2) (thread breakage detection).
Further, when the first thread break sensor 161 detects an ON / OFF signal with a predetermined period and the second thread break sensor 162 detects an ON / OFF signal with a predetermined period, the upper thread U2 that is not being sewn is detected. It is possible to detect the sewing abnormality being sewn (No. 3) (stop thread sewing detection).
Further, the first thread break sensor 161 detects an ON / OFF signal with a predetermined period, and the second thread break sensor 162 detects an ON signal that continues or an ON / OFF signal that does not have a predetermined period. It is possible to detect a sewing abnormality in which the upper thread U2 that is not in the middle is wound around the balance 141 (No. 4).
Further, when the first thread break sensor 161 detects an ON signal that continues or an ON / OFF signal that is not in a predetermined cycle, and the second thread break sensor 162 detects an OFF signal, the upper thread U1 that is being sewn. Can detect the sewing abnormality wound around the balance 141 (No. 5).
Further, an ON signal that the first thread break sensor 161 continues or an ON / OFF signal that is not in a predetermined cycle is detected, and an ON signal that the second thread break sensor 162 continues in or an ON / OFF signal that is not in a predetermined cycle By detecting this, it is possible to detect a sewing abnormality in which the upper thread U1 being sewn and the upper thread U2 not being sewn are wound around the balance 141 (No. 6).
Further, when the first thread break sensor 161 detects the OFF signal and the second thread break sensor 162 detects the ON / OFF signal of a predetermined cycle, the threading of the upper thread U1 and the upper thread U2 is reversed. A certain sewing abnormality (error in which the upper thread U1 is inserted into the sewing needle 12 and the upper thread U2 is inserted into the sewing needle 11) can be detected (No. 10) (error detection in reverse of threading).

During bobbin winding by the thread winding mechanism 19, the first thread break sensor 161 detects an OFF signal, and the second thread break sensor 162 detects an ON signal that continues or an ON / OFF signal that is not at a predetermined cycle. By doing so, it is possible to detect a sewing abnormality in which the upper thread U2 is wound around the balance 141 (No. 7).
Further, during bobbin winding by the thread winding mechanism 19, the first thread break sensor 161 detects an ON signal that continues or an ON / OFF signal that is not in a predetermined cycle, and the second thread break sensor 162 detects an OFF signal. By doing so, it is possible to detect a sewing abnormality in which the upper thread U1 is wound around the balance 141 (No. 8).
Further, while the bobbin thread is being wound by the bobbin winding mechanism 19, an ON signal that the first thread break sensor 161 continues or an ON / OFF signal that is not in a predetermined cycle is detected, and an ON signal that the second thread break sensor 162 continues. In addition, by detecting an ON / OFF signal that is not a predetermined cycle, it is possible to detect a sewing abnormality in which both the upper thread U1 and the upper thread U2 are wound around the balance 141 (No. 9).

  Data relating to a plurality of abnormal sewing patterns (No. 2 to No. 10), which is a combination of the detection signal of the first thread break sensor 161 and the detection signal of the second thread break sensor 162 as exemplified above, A table (see FIG. 14), which is used as a reference for determining whether the operation state of the sewing machine 100 is sewing abnormality, is stored and stored in the data memory 94, including data relating to the normal sewing state (No. 1). Yes. Note that a similar table that is used as a determination reference when sewing with the sewing needle 12 provided in the other needle bar 120 is also stored and stored in the data memory 94.

Then, when the CPU 91 of the control device 90 executes the sewing abnormality detection program stored in the ROM 92, the control device 90 (CPU 91) causes the two needle bars 110 and 120 to be driven and the two thread trimming sensors. Based on the combination of movements of the respective upper threads U1 and U2 detected by 161 and 162, it functions as a control means for determining the operation state of the two-needle sewing machine 100.
For example, the control means 90 for determining the operation status of the sewing machine 100 refers to a table (see FIG. 14) stored in the data memory 94, and when the situation matches the sewing abnormality pattern in the table, It is determined that the operation status is abnormal sewing.
Further, the control means for determining the operation state of the sewing machine 100 determines the sewing abnormality pattern selected via the operation panel 70 from among the plurality of sewing abnormality patterns stored in the data memory 94. It is set as an object, and when it is in a situation that matches the set sewing abnormality pattern, it is determined that the operation state of the sewing machine 100 is sewing abnormality.

When the control means for determining the operation status of the sewing machine 100 determines that the operation status of the sewing machine 100 is sewing abnormality, the control device 90 (CPU 91) stops the sewing machine motor 21 and stops the driving of the sewing machine 100. Execute the process.
In addition, when the control unit that determines the operation status of the sewing machine 100 determines that the operation status of the sewing machine 100 is sewing abnormality and stops the sewing machine 100, the control device 90 (CPU 91) causes the operation panel 70 to display the sewing machine 100. Execute the process to display the operating status of.

[Sewing machine operating status judgment process]
Next, the operation status determination process of the sewing machine 100 will be described based on the flowchart shown in FIG.

First, settings relating to abnormality detection are performed via the operation panel 70 (step S1).
For example, when performing sewing with the sewing needle 11 provided on one needle bar 110, the table No. shown in FIG. 1-No. 6, no. A setting for enabling detection of a sewing abnormality corresponding to 10 is performed, and the number of stitches (for example, 5 stitches) for determining that there is a sewing abnormality is set. (Note that when bobbin winding with the bobbin winding mechanism 19 is performed, the setting for enabling the detection of abnormality relating to No. 7 to No. 9 in the table shown in FIG. (Settings relating to abnormality detection can be made individually depending on when sewing is performed with sewing machine 100 and when bobbin thread winding is performed.)

Then, a sewing operation of the sewing machine 100 is started by pressing a start switch on the operation panel 70 and executing sewing (step S2).
Next, the control device 90 (CPU 91) confirms whether the needle bar selected and driven by the operation, setting, or sewing pattern data is the left needle bar 110 or the right needle bar 120 (step S3). The movements of the upper threads U1, U2 detected by the thread break sensors 161, 162 are confirmed (step S4).
Then, the control device 90 (CPU 91) determines the sewing machine based on the driving state of the two needle bars 110, 120 and the combination of the movements of the upper threads U1, U2 detected by the two thread trimming sensors 161, 162. The operation state of 100 is determined, and the presence or absence of sewing abnormality is determined (step S5). The determination as to whether or not there is a sewing abnormality is made according to No. in the table of FIG. 1-No. 6, no. 10 is determined based on the sewing abnormality pattern corresponding to 10.

When the control device 90 (CPU 91) detects a sewing abnormality (step S6; YES), the number of stitches for abnormality detection is incremented by one (step S7). The number of stitches is counted based on the signal from the sewing machine spindle motor.
Next, the control device 90 (CPU 91) determines whether or not the number of stitches for abnormality detection has reached the number of stitches (for example, five stitches) set in step S1 (step S8).
When the control device 90 (CPU 91) determines that the number of stitches for abnormality detection has not reached the number of stitches set in step S1 (5 stitches) (step S8; NO), the process returns to step S3.
On the other hand, when the control device 90 (CPU 91) determines that the number of stitches for abnormality detection has reached the number of stitches (5 stitches) set in step S1 (step S8; YES), the control device 90 (CPU 91) causes the sewing machine motor to operate. 21 is stopped and the sewing machine 100 is urgently stopped (step S9). Further, the control device 90 (CPU 91) displays the determination result of the abnormality detection on the display unit of the operation panel 70 so as to make an emergency stop. For example, the sewing abnormality pattern No. In the case of 2, the display of the operation panel 70 displays “Thread breakage detection of upper thread of left needle bar (sewing needle)”.

In step S6, if the control device 90 (CPU 91) has not detected a sewing abnormality (step S6; NO), the number of stitches for abnormality detection is reset to zero (step S10).
When the control device 90 (CPU 91) determines that the sewing of the predetermined sewing pattern has not been completed (step S11; NO), the process returns to step S3.
On the other hand, when the control device 90 (CPU 91) determines that the sewing of the predetermined sewing pattern has been completed (step S11; Yes), the control device 90 (CPU 91) stops the sewing machine motor 21 and normally stops the sewing machine 100 ( Step S12), the sewing operation is terminated.

The operation status determination process of the sewing machine can be variously changed.
For example, the number of stitches with abnormal sewing may be preset as an initial value at the time of shipment, or when the operator newly sets the number of new stitches with abnormal sewing, the setting is applied at the next sewing. Also good.
In the above embodiment, when an abnormality is detected in step S6, the number of abnormality detection needles is counted in step S7, and it is determined whether or not the number of abnormality detection needles has been reached in step S8. Alternatively, when an abnormality is detected, the feed amount of at least one of the X-axis motor 83 and the Y-axis motor 84 that move the holding frame 81 is counted, and it is determined whether or not the abnormality detection feed amount has been reached. good. Further, when an abnormality is detected, the time may be measured, and for example, when the abnormality continues for 3 seconds, it may be determined that the abnormality detection time has been reached. The number of abnormality detection needles, the abnormality detection feed amount, and the abnormality detection time are collectively referred to as an abnormality detection standard.
FIG. 14 is a table that serves as a reference for determining whether or not the operation state of the sewing machine is sewing abnormality. In this table, when the movement of the upper thread during sewing is normal, the sensors 161 and 162 detect ON / OFF signals of a predetermined cycle. However, when the response speed of the sensors 161 and 162 used is slow or when the sewing speed is high, even if the movement of the upper thread during sewing is normal, the sensors 161 and 162 are not turned ON / OFF at a predetermined cycle and are fed out. An ON signal that continues to be detected or an ON / OFF signal that is not in a predetermined cycle is detected. As a result, No. 1 in FIG. 1, no. 2, No. 3, no. 10 and no. 4 to No. There is a possibility that it cannot be divided into 10.
In order to avoid such an erroneous determination, it is easily conceivable to use the operating condition reference table of the sewing machine shown in FIG. This operation condition reference table is composed only of No1, No2, No3, and No10. The “ON or ON-OFF cycle” in this table means a state in which an ON signal that is continuously delivered, an ON / OFF signal having a predetermined cycle, or an ON / OFF signal that is not a predetermined cycle is detected. If the sewing machine operating condition reference table shown in FIG. 16 is used, the operating condition of the sewing abnormality can be determined more reliably.
In addition, it is easily conceivable to use one of stop thread sewing detection and reverse threading error detection as an operation state of the sewing abnormality.
The bobbin winding mechanism 19 is driven by a touch operation on the operation panel 70. Therefore, the control device 90 can recognize that the bobbin is being wound upon receiving an input signal from the operation panel. From the signal being wound, the No. of FIG. 7, no. 8, no. It is also conceivable that the control device 90 can recognize the winding of the balance yarn during winding by adding 9.

[Effects of Embodiment]
The sewing machine 100 is a two-needle sewing machine 100 that is switched to drive one of the two needle bars 110 and 120 by operation or setting and performs sewing with a sewing needle provided in the selected needle bar. Two sensors 161 and 162 for detecting the movement of the upper thread respectively supplied to the sewing needle of one needle bar to be selected and driven and the sewing needle of the other needle bar to be stopped and not driven; Control means 90 is provided for determining the operating state of the two-needle sewing machine based on the driving state of the two needle bars and the combination of the movements of the respective upper threads detected by the two sensors.
Further, the control means 90 is characterized in that the two-needle sewing machine is stopped in accordance with the determination that the operation state of the two-needle sewing machine is a sewing abnormality.
And a storage means 94 for storing a plurality of sewing abnormality patterns, each of which includes a combination of the driving states of the two needle bars and the movements of the respective upper threads detected by the two sensors 161 and 162. 90 is characterized in that, when the situation matches the sewing abnormality pattern stored in the storage means 94, it is judged that the operation state of the two-needle sewing machine is a sewing abnormality.
Further, the control unit 90 includes a setting unit 90 that selects and sets a sewing abnormality pattern to be determined as an operation status of the two-needle sewing machine among the plurality of sewing abnormality patterns stored in the storage unit. When it is a situation that matches the sewing abnormality pattern set by 90, it is determined that the operation state of the two-needle sewing machine is a sewing abnormality.
Further, the sewing abnormality determined by the control means 90 includes the detection of stop thread stitching.
Further, the display device 70 is provided which displays the operation status of the two-needle sewing machine determined by the control means 90.

  As described above, the sewing machine 100 not only detects abnormalities related to thread breakage as in the prior art, but also combines the movements of the upper threads U1 and U2 detected by the existing two thread breakage sensors 161 and 162, respectively. Since various sewing abnormalities can be detected based on the above, various abnormalities can be efficiently detected without adding a new sensor.

[Others]
The above-described needle bar switching mechanism 30 is not limited to the electronic cycle sewing machine, and may be applied to various sewing machines such as a so-called lockstitch sewing machine. In the case of application to a lockstitch sewing machine, it is desirable to provide input means (such as an operation panel 70) for an operator to instruct the sewing machine control device 90 to execute switching of the needle bars 110 and 120.

In addition, the switching lever 332 of the stop selection unit 33 has a structure including push-in protrusions 332b and 332c protruding outward in the radial direction, and switches the holding state of the needle bars 110 and 120 in the “switching of sewing needles to be used” operation. At this time, the needle bar 110 or 120 held by the needle bar holder 25 is prevented so that the pin-shaped portions 321a and 321a protruding from the upper ends of the needle bars 110 and 120 do not interfere with the pushing protrusions 332b and 332c. The switch lever 332 is rotated when it is in the upper stop position after passing through the top dead center, and then the upper shaft 22 is rotated in the reverse direction to return to the top dead center position to push in the pin-shaped portion 321a.
Here, as shown in FIG. 17, the push-in protrusions 332b and 332c of the switching lever 332 may be connected by a tapered portion 332d that gradually reduces the diameter, and may be formed in an outer peripheral cam shape. As a result, the switching lever 332 can be rotated without interference between the pin-shaped portion 321a of the needle bar 110 or 120 held by the needle bar holder 25 and the pushing protrusion 332b or 332c.
Accordingly, during the “switching of the sewing needle to be used” operation, the sewing machine motor 21 is stopped not at the upper stop position but at the needle bar top dead center, and in this state, thread trimming, rotation of the needle bar base 31, It is possible to rotate the switching lever 332 to switch the needle bars 110 and 120 and resume sewing as it is. That is, the reverse rotation operation of the sewing machine motor 21 is unnecessary, and the needle bar switching operation can be performed quickly.

[Other examples of thread holding device]
Further, instead of the thread holding device 60 shown in FIG. 9, the sewing machine 100 may be equipped with a thread holding device 60A shown in FIGS.
The thread holding device 60A includes a movable holding member 61A fixedly provided near the right side surface of the needle bar base 31 and two movable holding members 61A that are close to and opposed to the movable holding member 61A on both sides in the swinging direction of the needle bar base 31. And a fixed holding member 62A provided with opposing portions 621A and 622A.
The upper end of the movable holding member 61A is fixed by two screws at the right end of the front surface of the needle bar base 31. A lower end portion of the movable holding member 61A is formed with a yarn holding portion 611A that is bent toward the rear in the Y-axis direction. The thread holding portion 611A has a round bar shape along the Y-axis direction.
The left and right side edge portions 611Aa and 611Ab on the outer peripheral surface of the yarn holding portion 611A are opposed to the facing portions 621A and 622A of the fixed holding member 62A, respectively.
The fixed holding member 62 </ b> A is disposed near the right side of the needle bar base 31. The two opposing portions 621A and 622A of the fixed holding member 62A are both in a flat plate shape that is parallel to the Y-axis direction and slightly inclined with respect to the Z-axis direction, and is substantially inverted U-shaped when viewed from the Y-axis direction. The upper parts of each other are integrally connected so as to form a shape. The fixed holding member 62A is fixed to the frame of the surface portion 105 by the support portion 625A.
Further, the connecting portion of the two opposing portions 621A and 622A has a semi-cylindrical shape, and penetrates the connecting portion up and down to insert the upper thread U1 on the sewing needle 11 side and the upper side on the sewing needle 12 side. A threading hole 624A through which the thread U2 is inserted is formed.
Both the threading holes 623A and 624A are formed in a slit shape along the X-axis direction. The threading hole 623A is formed in the range from the connecting portion of the facing portions 621A and 622A to the facing portion 621A, and the threading hole 624A is formed in the range from the connecting portion of the facing portions 621A and 622A to the facing portion 623A. Yes.
Thereby, the threading hole 623A guides the upper thread U1 inserted from above to the first threading part between the opposing part 621A and the left side edge part 611Aa on the outer peripheral surface of the thread holding part 611A, The threading hole 624A enables the upper thread U2 inserted from above to be guided to the second threading part between the facing part 622A and the left side edge part 611Ab on the outer peripheral surface of the thread holding part 611A. Yes.
Since the movable holding member 61A is mounted on the needle bar base 31 that reciprocally swings along the X-axis direction, the lower end portion of the needle bar base 31 is positioned at the right when the sewing needle 11 is selected by the switching drive unit 34. When it is swung to the right, the right edge 611Ab of the thread holding portion 611A of the movable holding member 61A comes into contact with the facing portion 622A side of the fixed holding member 62A. As a result, the upper thread U2 on the side of the sewing needle 12 that is not used is held between them, and it is possible to prevent the upper thread U2 from being pulled out of the sewing needle 12 against the lifting operation of the balance 141.
Further, when the sewing needle 12 is selected by the switching drive unit 34, the lower end portion of the needle bar base 31 swings to the left, so that one side edge portion 611Aa of the thread holding portion 611A of the movable holding member 61A is fixed to the fixed holding member. It contacts one opposing portion 621A side of 62A. As a result, the upper thread U1 on the side of the sewing needle 11 that is not used is held between them, and it is possible to prevent the upper thread U1 from being pulled out of the sewing needle 11 against the lifting operation of the balance 141.
In the case of the thread holding device 60A, the entire device can be disposed on the right side of the needle bar base 31 and is in the middle of the upper thread path from the balance 141 to the needle bar thread guide 36 provided in the vicinity of the sewing needles 11 and 12. Therefore, the upper threads U1 and U2 can be smoothly guided.

  The application of the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit of the present invention.

21 sewing machine motor 22 upper shaft 25 needle bar holder 30 needle bar switching mechanism 31 needle bar base 32 needle bar stop unit 33 stop selection unit 34 switching drive unit 70 operation panel (setting means, display unit)
90 Control device (control means, setting means)
91 CPU
92 ROM
93 REAM
94 Data memory (storage means)
100 Sewing machine 11, 12 Sewing needle 110, 120 Needle bar 14 Balance mechanism 161 First thread trimming sensor 162 Second thread trimming sensor 19 Thread winding mechanism U1 Upper thread U2 Upper thread

Claims (6)

A two-needle sewing machine which is switched to driving one of the two needle bars by operation or setting and performs sewing with a sewing needle provided in the selected needle bar,
Two sensors for detecting the movement of the upper thread respectively supplied to the sewing needle of one needle bar that is selected and driven and the sewing needle of the other needle bar that is stopped and not driven;
Control means for determining the operating state of the two-needle sewing machine based on the driving state of the two needle bars and the combination of the movements of the respective upper threads detected by the two sensors;
A two-needle sewing machine characterized by comprising:   2. The two-needle sewing machine according to claim 1, wherein the control unit stops the two-needle sewing machine in accordance with the determination that the operation state of the two-needle sewing machine is abnormal sewing. A storage means for storing a plurality of sewing abnormality patterns, each of which includes a combination of a driving state of the two needle bars and movements of the respective upper threads detected by the two sensors;
2. The control unit according to claim 1 or 2, wherein when the situation coincides with a sewing abnormality pattern stored in the storage unit, the operation state of the two-needle sewing machine is a sewing abnormality. 2. A two-needle sewing machine according to 2. Among the plurality of sewing abnormality patterns stored in the storage means, a setting means for selecting and setting a sewing abnormality pattern to be determined for the operation status of the two-needle sewing machine is provided.
4. The control unit according to claim 3, wherein the control unit determines that the operation state of the two-needle sewing machine is a sewing abnormality when the sewing unit is in a state that matches the sewing abnormality pattern set by the setting unit. The two-needle sewing machine as described.   The two-needle sewing machine according to any one of claims 1 to 4, wherein the sewing abnormality determined by the control means includes detection of stop thread sewing or detection of an error in reverse of threading.   The two-needle sewing machine according to any one of claims 1 to 5, further comprising a display unit that displays an operation state of the two-needle sewing machine determined by the control unit.

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