JP3022651B2 - Sewing machine control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewing machine control device provided with a thread feeding mechanism and a thread cutting mechanism, and more particularly to a thread cutting operation of a movable blade when cutting an upper thread and a lower thread by the thread cutting mechanism. The present invention relates to an arrangement in which a necessary upper thread is fed from a thread spool by a required amount at a required time.

[0002]

2. Description of the Related Art Conventionally, in electronic sewing machines and the like, a plurality of types of stitches such as practical stitches and pattern stitches can be formed.
A thread feeding mechanism that feeds the upper thread necessary for forming the next stitch from the thread spool during sewing is provided in the arm, and a thread cutting mechanism that cuts the upper and lower and lower threads connected to the work cloth at the end of sewing is provided in the bed. The provided one is provided for practical use.

[0003] In a sewing machine provided with such a thread feeding mechanism and a thread cutting mechanism, when a command to cut the thread is issued, usually,
The movable blade of the thread trimming mechanism is configured in conjunction with the rotation of the upper shaft of the sewing machine so as to reciprocate from a phase past the lowermost position of the balance to a phase near the uppermost position of the balance. When moved to the position, the upper thread and the lower thread are cut by the cooperation of the movable blade and the fixed blade.

Here, in order to cut the yarn, at the initial stage of the forward movement of the movable blade, that is, immediately before the lowermost position of the balance, the tip of the movable blade has a substantially triangular upper thread formed by a yarn catcher. It is necessary to extend the period of forming the approximately triangular upper thread loop so that the thread can be securely inserted inside the loop.
It is necessary to unwind the upper thread somewhat (for example, about 20 mm) as a necessary thread amount. Furthermore, when the movable blade that has engaged the upper thread and the lower thread is moved backward, a large amount (for example, about 50 mm) of the upper thread is required as the second necessary thread amount due to the backward movement of the movable blade. But,
The required thread amount (for example, about 70 mm) obtained by adding the first required thread amount and the second required thread amount is determined by the thread feeding mechanism by the thread feeding mechanism when the balance is at a predetermined timing from the uppermost position to the lowermost position. From a single time.

[0005]

As described above, in an electronic sewing machine provided with a thread feeding mechanism and a thread cutting mechanism,
The large amount of thread required for thread cutting is fed out from the thread spool at a timing considerably earlier than this thread cutting operation, that is, at a predetermined timing from the uppermost position to the lowermost position. Until most of the upper thread is completely consumed as the second necessary thread amount by the return movement of the movable blade, the thread is slackened on the thread path from the thread feeding mechanism via the balance to the eye hole of the sewing needle. There is a problem that the upper thread is entangled with various components of the drive system near the yarn path, so that the thread cutting operation cannot be performed smoothly.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sewing machine which can prevent a needle thread pulled out from a thread spool by a thread feeding mechanism during thread cutting by a thread cutting mechanism from becoming entangled with various components of a drive system near a yarn path. It is to provide a control device.

[0007]

As shown in the functional block diagram of FIG. 1, a control device for a sewing machine according to the present invention includes a phase detecting means for detecting a rotation phase of an upper shaft of the sewing machine, and a bed inside the sewing machine main body. A thread trimming mechanism provided at the upper side and capable of cutting the upper thread and the lower thread, a thread feeding mechanism for feeding the upper thread from the upper thread supply source in a thread path from the upper thread supply source to the balance, and a In a sewing machine provided with an electromagnetic actuator that controls a thread feeding amount, when a thread trimming command is input to a thread trimming mechanism, a predetermined number of times during shifting to the bottom dead center of the balance based on the output of the phase detecting means is determined. An electromagnetic actuator for feeding out a first predetermined amount of upper thread at one timing, and feeding a second predetermined amount of upper thread at a second predetermined timing during the transition to the top dead center of the balance after the first timing. With control means for controlling the It is.

[0008]

In the sewing machine control device according to the present invention, when a thread trimming command is input, a predetermined balance during the transition to the bottom dead center of the balance is determined based on the rotation phase of the upper shaft detected by the phase detecting means. The electromagnetic actuator is controlled so as to feed out a first predetermined amount of the upper thread at the first timing, and the second predetermined amount is transferred at a predetermined second timing during the transition to the top dead center of the balance after the first timing. The electromagnetic actuator is controlled so as to feed the upper thread.

Here, in general, the movable blade of the thread trimming mechanism reciprocates from the timing near the bottom dead center to the timing near the top dead center in synchronization with the rotation of the upper shaft of the sewing machine. If the first timing is set, for example, immediately before the bottom dead center of the balance, when the upper thread loop moves below the inner shuttle due to rotation of the outer shuttle of the yarn catcher provided in the bed, Since the timing of disengaging from the engagement with the inner hook rotation stopping member due to the rotation of the sword tip of the outer hook can be delayed until the first predetermined amount of the upper thread is consumed, the upper thread loop is stably formed in a substantially triangular shape. As a result, the leading end of the movable blade of the thread cutting mechanism can be reliably inserted into the upper thread loop. Further, if the second timing is set, for example, immediately before the top dead center of the balance, the second predetermined amount of the upper thread is fed out immediately before the top dead center of the balance. The second predetermined amount of the upper thread that has been fed at the time of cutting) is consumed immediately after being fed.

[0010]

According to the sewing machine control apparatus of the present invention, as described in the section of [Operation], the control means is provided,
When a thread trimming command is input, the electromagnetic actuator is controlled so as to feed out a first predetermined amount of upper thread at a predetermined first timing. Therefore, the tip of the movable blade of the thread trimming mechanism is inserted into the upper thread loop. It can be reliably inserted. Meanwhile, the first
Since the electromagnetic actuator is controlled so as to feed out the second predetermined amount of the upper thread at the predetermined second timing after the timing, the movable blade immediately after feeding out the second predetermined amount of the upper thread is moved by the reciprocation of the movable blade. Can be completely consumed. Thus, the upper thread necessary for the thread cutting operation is fed out of the thread spool by a necessary amount at a necessary time, so that the upper thread fed from the thread spool at the time of thread cutting extends from the thread feeding mechanism to the eye of the sewing needle. It is possible to reliably prevent entanglement with various components of the drive system in the vicinity of the yarn path, and to smoothly perform the yarn cutting operation.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, the present invention is applied to an electronic control sewing machine having a thread feeding mechanism and a thread cutting mechanism. As shown in FIG. 2, the electronic control sewing machine M includes a sewing machine bed 1, a pillar 2 erected from the right end of the bed 1, and a bed 2 facing the bed 1 from the pillar 2. And an arm 3 extending to the left.
Inside, a feed dog vertical movement mechanism (not shown) for moving the feed dog up and down and a feed dog front and rear movement mechanism (not shown) for moving back and forth,
A horizontal hook 25 and a hook driving mechanism (not shown) for driving the horizontal hook 25 are provided. The arm 3 has a needle bar driving mechanism for vertically moving a needle bar 5 on which a sewing needle 6 can be mounted at a lower end thereof.
A needle bar swinging mechanism for swinging the needle bar 5 in a direction orthogonal to the cloth feeding direction, a balance driving mechanism (not shown) for moving the balance 7 up and down in synchronization with the vertical movement of the needle bar 5, and a thread spool 8 A yarn feeding mechanism 45 for feeding the upper thread 10 from the thread spool 8 to the thread supply path to the balance 7
And so on. The head 4 is provided with a plurality of switches, such as a start / stop switch 35 for instructing start and stop of the sewing operation, and a thread trimming switch 36 for instructing thread trimming. The feed dog vertical movement mechanism, the needle bar drive mechanism and the balance drive mechanism are driven by a sewing machine motor 85, and the feed dog longitudinal movement mechanism is a stepper motor 8 for driving the feed dog.
7, and the needle bar swing mechanism is driven by a needle bar swing stepping motor 86. Reference numeral 13 denotes a presser bar, and reference numeral 14 denotes a presser foot attached to a lower end of the presser bar 13.

Next, the yarn feeding mechanism 45 for feeding the upper thread 10 from the thread spool 8 will be described with reference to FIGS. A mounting base 46 is fixed to the machine frame 12.
A threading stepping motor 48 is attached to the motor 48 with screws 50, and an output gear 52 is fixed to a drive shaft 48a of the motor 48. A drive gear 54 meshing with the output gear 52 is rotatably supported on a mounting base 46 by a rotation shaft 56. A drive roller 58 is fixed to the rotation shaft 56, and the drive roller 58 is configured to rotate integrally with the drive gear 54.

The swing lever 60 is rotatably supported by a pivot shaft 62 fixed to the mounting base 46.
0 is the first arm 60a, the second arm 60b, and the third arm 6
0c are respectively formed. A tension spring 64 is stretched across the first arm portion 60a and the mounting base 46, and the swing lever 60 is constantly urged to rotate counterclockwise. A roller holder 68 having a substantially triangular shape in a plan view is provided on the second arm portion 60b.
Is rotatably supported by a pivot shaft 66, and the other end of the roller holder 68 has a rotary shaft 56 inserted through a long hole formed therein. In the vicinity of the other end of the roller holder 68, a rubber driven roller 70 is rotatably supported by a pivot 72 fixed to the roller holder 68, and a rubber driven roller 71 is provided. Roller holder 6
8 is rotatably supported by a pivot shaft 73 fixed thereto.
Accordingly, the pair of driven rollers 70 and 71 are pressed by the arrow 74 so that the pair of driven rollers 70 and 71 are pressed against the driving roller 58 via the roller holder 68 by the rotation urging of the swing lever 60 in the counterclockwise rotation direction.
The upper thread 10 supplied between the driving roller 58 and the driven rollers 70 and 71 is elastically urged in the direction, and is configured to elastically press and clamp the upper thread 10.

The third arm portion 60c is operatively connected to the presser bar 13, and an operation lever (not shown) for raising and lowering the presser bar 13.
Is operated to raise the presser foot 14 to the rest position, the swing lever 60 is rotated clockwise against the spring force of the tension spring 64, and the pair of driven rollers 70 and 7 is rotated.
1 is separated from the drive roller 58, respectively, and the upper thread 10 is released from being pressed and clamped by the driven rollers 70 and 71 and the drive roller 58.

Next, a thread cutting mechanism 20 provided in the bed 1 for cutting the upper thread 10 and the lower thread 11 will be described with reference to FIG.
A description will be given based on FIG. Since the thread cutting mechanism 20 is the same as that generally used, the movable blade 21
And the fixed blade 22 will be briefly described.

As shown in FIGS. 4 and 5, a fully rotating horizontal shuttle 25 is provided in the bed portion 1. The horizontal shuttle 25 rotates around a vertical axis in a horizontal plane. An inner shuttle 27 is held in a stationary state in a shuttle 26, and a lower thread bobbin 28 rotatably accommodated in the inner shuttle 27 is provided. Further, a protrusion 27a protruding upward is formed on a part of the outer periphery of the inner pot 27, and in order to prevent the inner pot 27 from rotating counterclockwise with the rotation of the outer pot 26, this protrusion is formed. Leaf spring member (hook stopper) 2 abutting on projection 27a
9 is attached to the machine frame 12 by a fixture 30. A lower shaft 31 rotatably driven by a sewing machine motor 85 is rotatably supported in the bed 1, and the rotation of the lower shaft 31 is transmitted to the horizontal shuttle 25 between the lower shaft 31 and the outer shuttle 26. Gear transmission mechanism (not shown) is provided.

As shown in FIG. 4 and FIG.
The movable blade 21 is positioned just above the movable blade 21 so as to be movable in its length direction. The movable blade 21 has a blade portion, and extends between a cutting position shown in FIG. 4 and an engagement position shown in FIG. Can be moved. Further, there is provided a fixed blade 22 for cutting the upper thread 10 and the lower thread 11 in cooperation with the movable blade 21 when the movable blade 21 returns to the cutting position. In addition, this movable blade 2
1 starts the operation of the movable blade drive mechanism (not shown) connected to the lower shaft 31 by driving the thread cutting solenoid (see FIG. 6), and as shown in FIG. It is moved from the cutting position to the engaging position over 360 ° and from the engaging position to the cutting position over a phase angle of about 30 ° to about 90 °. When the needle bar 5 is at its uppermost position, the phase angle is 0 °. Reference numeral 32 denotes a bobbin holding mechanism that imparts resistance to the rotation of the bobbin bobbin 28 that is rotated by the bobbin thread 11 that is fed during thread trimming.

Here, the thread cutting operation of the thread cutting mechanism 20 will be briefly described with reference to FIGS. 4, 5, and 8. When a thread cutting command is input, the movable blade 21 moves toward the engagement position. At a phase angle of about 325 ° immediately after the start of the movement (phase angle of about 320 °), as shown in FIG. 5, the outer hook 26 is substantially formed by engagement with the sword tip 26 a and engagement with the leaf spring member 29. In order to reliably insert the tip of the movable blade 21 into the inside of the upper thread loop of the triangular upper thread 10, it is necessary to extend the period in which the upper thread loop is engaged with the leaf spring member 29. For this purpose, it is necessary to advance the upper thread 10 from the thread spool 8 by the first necessary thread amount (for example, about 20 mm) at a timing up to the phase angle of 325 °. on the other hand,
The movable blade 21 returns from the engaged position to the cutting position shown in FIG.
°, the two yarns 10 and 11 are cut, and the second necessary yarn amount (for example, about 5
0 mm) of the upper thread 10. still,
At the time of normal sewing, the thread amount necessary for forming the next stitch is fed at the thread feeding timing T1 (phase angle: about 152 °).

Next, an outline of a control system of the sewing machine M is configured as shown in a block diagram of FIG. A start / stop switch 35, a thread trimming switch 36, a pattern selection switch 37 for selecting a desired stitch pattern, and a phase detector 3
8 and the needle position signal generator 39 are connected to an input / output interface 89 of the control device C, respectively. The input / output interface 89 includes a driving circuit 80 for a sewing machine motor 85, a driving circuit 81 for a needle bar swinging stepping motor 86, and a feed dog driving stepping motor 8
7, a driving circuit 83 for the thread feeding stepping motor 48, and a driving circuit 84 for the thread cutting solenoid 88 are connected to each other. As shown in FIG. 2, the phase detector 38 is composed of a photo interrupter, detects a large number of slits formed on an outer peripheral portion of a circular disk plate 40 attached to the upper shaft 9, and outputs a slit signal. The needle position signal generator 39 is also formed of a photo interrupter, and corresponds to the notch formed in the disk plate 41 attached to the upper shaft 9, and corresponds to the timing needle upper signal of the uppermost position of the sewing needle 6. , And outputs a needle down signal at the timing of the lowest position of the sewing needle 6, respectively.

The control device C comprises a CPU 91 and this CPU
An input / output interface 89 connected to a data bus 91 via a bus 90 such as a data bus, a ROM 92 and a RAM 93 are provided.

In the ROM 92, the stitch data of the stitch patterns of the practical stitches and the pattern stitches are stored for each pattern type in association with the code numbers of the stitch patterns. Also stores a control program for pattern stitching control for sequentially reading and sewing the stitch data of each of the stitch patterns selected and set. Further, the ROM 92 stores the motor 4
8.85-87, a drive control program for driving the solenoid 88, a control program for sequentially counting slit signals inputted from the phase detector 38 and outputting various timing signals, a control program for needle thread feeding control described later, etc. Is stored. Further, in the ROM 92, the first feeding amount corresponding to the first necessary yarn amount at the yarn feeding timing T2 is stored.
Stepping motor 48 for feeding the yarn in accordance with the amount of the supplied yarn
Of the number of pulses P1 for driving the yarn feeding stepping motor 48 corresponding to the second supply yarn amount to be fed corresponding to the second necessary yarn amount at the yarn feeding timing T3. Data is stored. RA
M93 is a pattern memory for storing pattern numbers of a plurality of stitch patterns selected by operating the pattern selection switch 37;
A pointer, a counter, a buffer, and the like for temporarily storing the calculation result calculated by the CPU 91 are provided.

Next, a description will be given, with reference to FIG. 8, of the upper thread feeding control routine performed by the control device C of the sewing machine M, based on the flowchart of FIG. In the figure, reference numerals Si (i = 30, 31, 32,...) Indicate each step.

When the sewing control is started by operating the start / stop switch 35, this control is started, and at the timing T1 (the phase angle is about 152 °) for thread feeding, (S
30: Yes), the upper thread 10 necessary for forming the next stitch pattern
The required thread amount is calculated (S31), and in accordance with the required thread amount, the thread delivery stepping motor 48 is driven to deliver the upper thread 10 from the thread spool 8 (S32), and the thread trimming switch 36 is operated. If the thread cutting flag FC is reset (S33: No), S30 and the subsequent steps are repeatedly executed.

When the thread trimming switch 36 is operated during sewing and the thread trimming flag FC is set (S33: Yes), the first supply amount set immediately before the lowermost position of the balance 7 is increased. Timing T2 for unwinding the yarn 10
The determination in S34 is repeated until the timing is reached. When the yarn feeding timing T2 is reached (S34: Yes), the yarn feeding stepping motor 48 is driven based on the pulse number P1 of the first supply amount, and the first necessary yarn is fed. Quantity (eg, about 2
The upper thread (0 mm) is fed from the thread spool 8 (S35). Therefore, as described above with reference to FIG.
Since the upper thread loop stably forms a substantially triangular shape in the vicinity, the tip of the movable blade 21 can be reliably inserted into the upper thread loop. As a result, the movable blade 21 can securely engage the two yarns 10 and 11 with the hook portion 21a.

Next, the determination of S36 is repeated until the timing T3 at which the second supply amount of the upper thread 10 set immediately before the uppermost position of the balance 7 is delivered, and when the thread delivery timing T3 is reached. (S36: Yes), second
The yarn feeding stepping motor 48 is driven based on the supply amount pulse number P2, and the second necessary yarn amount (for example, about 50
mm) of the upper thread 10 is unwound from the thread spool 8 (S37), and this control ends. Therefore, as described above with reference to FIG. 4, the upper thread 10 has been fed by the second necessary thread amount necessary for the return movement of the movable blade 21 to the cutting position.
Is returned from the engagement position to the cutting position in a state where both yarns 10 and 11 are engaged, and both yarns 10 and 11 are cut at a phase angle of about 75 °.

As described above, when the thread trimming command is input, the thread supply stepping is performed such that the first supply amount of the upper thread 10 is delivered at the thread delivery timing T2 immediately before the lowermost position of the balance 7. Since the motor 48 is driven, when the upper thread loop goes around the outside of the inner shuttle 27 of the horizontal shuttle 25, the timing at which the upper thread loop is disengaged from the leaf spring member 29 is the first timing.
Since it is delayed until the supply amount of the upper thread 10 is consumed, the period in which a stable triangular upper thread loop is formed is extended, and the tip of the movable blade 21 is securely inserted into the upper thread loop. be able to. On the other hand, the yarn feeding timing T
Since the thread feeding stepping motor 48 is driven so as to feed the upper thread 10 of the second supply amount at the thread feeding timing T3 immediately before the uppermost position of the balance 7 after 2, this second step is performed when the movable blade 21 moves backward. The two supply amounts of the upper thread 10 can be consumed immediately after being fed out. As a result, the required amount of the upper thread 10 required for the thread cutting operation is fed from the thread spool 8 by a required amount each time at a necessary time.
Can be reliably prevented from being entangled in the drive system adjacent to the thread path extending from the thread feeding mechanism 45 to the eye of the sewing needle 6,
The thread cutting operation can be performed smoothly.

The yarn feeding mechanism 45 and the yarn cutting mechanism 20 are not limited to those in the above-described embodiment, and various existing mechanisms can be used. The present invention can be similarly applied to a case where thread trimming command data is provided at the end of the stitch data and thread trimming is automatically performed based on the thread trimming command data. If the timing of thread trimming is set earlier than the timing of the above-described embodiment, depending on the configuration of the thread trimming mechanism, the thread pay-out timing T3 is also advanced accordingly, and the thread pay-out timing T3 is set to the balance. The timing may be set earlier than the bottom dead center. Note that, as the thread trimming and feeding mechanism, a mechanism in which a drive roller for threading is linked to an upper shaft via an electromagnetic clutch mechanism is also applicable, and in this case, the solenoid of the electromagnetic clutch mechanism determines that the This is equivalent to a “controlled electromagnetic actuator”.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing a configuration of the present invention.

FIG. 2 is a front view of the electronic control sewing machine with a part cut away.

FIG. 3 is a plan view of the yarn feeding mechanism.

FIG. 4 is a partial plan view showing the horizontal shuttle and the movable blade in the bed when the movable blade is located at a cutting position.

FIG. 5 is a diagram corresponding to FIG. 4 when the movable blade is located at an engagement position.

FIG. 6 is a block diagram of a control system of the electronic control sewing machine.

FIG. 7 is a schematic flowchart of a routine of needle thread payout control.

FIG. 8 is a time chart showing the operation of each mechanism of the sewing machine.

[Explanation of symbols]

 M Electronically controlled sewing machine 7 Balance 8 Thread spool 9 Upper shaft 10 Upper thread 11 Lower thread 20 Thread trimming mechanism 21 Movable blade 22 Fixed blade 36 Thread trimming switch 38 Phase detector 45 Thread feeding mechanism 48 Thread feeding stepping motor 58 Drive roller 91 CPU 92 ROM 93 RAM

Claims (1)

(57) [Claims] 1. A phase detecting means for detecting a rotation phase of an upper shaft of a sewing machine, a thread cutting mechanism provided in a bed of a sewing machine main body and capable of cutting an upper thread and a lower thread, and an upper thread supply source to a balance. A sewing machine provided with a yarn feeding mechanism for feeding an upper thread from an upper thread supply source in the yarn path, and an electromagnetic actuator for controlling an upper thread feeding amount of the thread feeding mechanism. When this is done, a first predetermined amount of the upper thread is fed out at a predetermined first timing during the transition to the bottom dead center of the balance based on the output of the phase detection means, and the top dead center of the balance after the first timing is output. A control device for a sewing machine, further comprising control means for controlling an electromagnetic actuator so as to feed out a second predetermined amount of upper thread at a predetermined second timing during the transition to a point.