JPS6114836B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling an electronic sewing machine, and particularly to a method for controlling an electronic sewing machine.
The present invention relates to a method of controlling an electronic sewing machine that uses two motors to automatically form sewing patterns stored in a memory.

In recent years, motors for moving the needle from side to side (hereinafter referred to as needle motors), cloth feed positioning motors that determine the initial position (front or rear) of cloth feed (hereinafter referred to as cloth motors), A total of three motors are used: the main sewing machine motor, which moves the needle up and down and lifts the cloth feeder to move it from the initial position to the center position.The needle motor and cloth motor are each stored in memory. 2. Description of the Related Art An electronic sewing machine, commonly known as a computer sewing machine, has been developed that is driven in accordance with a signal representing a given sewing pattern and automatically forms a predetermined sewing pattern on cloth.

FIG. 1 is an explanatory diagram schematically showing an example of the electronic sewing machine of the type described above. In the figure, 1 moves the needle up and down, lifts the cloth feeder to the top, and moves it from the initial position to the center position. Shows the main motor. The rotational speed of the main motor 1 is normally controlled by a speed control circuit 2, and the speed control circuit 2 is controlled by an external operation A such as a foot or hand of the sewing machine user. Each rotation of the main motor 1 involves, for example, a disk 3 having one slit attached to the motor rotation shaft, a lamp disposed opposite to each other on both sides of the disk 3, a light source 4 such as a light emitting diode, and a photo source 4 such as a light emitting diode.
It is detected by a photoelectric element 5, such as a transistor or a phototube, and one pulse is generated by the photoelectric element 5 for each revolution. This pulse output is waveform-shaped by a Schmitt circuit 6 and sent to a needle differential shaping circuit 7 and a cloth feeding differential shaping circuit 8. Pulse outputs from the differential shaping circuits 7 and 8 are given as trigger pulses to a needle memory 9 and a cloth feeding memory 10, respectively, and these memories 9 and 10 are used to select pattern selection switches 11 and 1.
2, the output corresponding to the preset pattern is read out and sent to the digital-to-analog converter 13.
After being converted into an analog signal by and 14,
The signal is supplied to a motor servo amplifier 15 for moving the needle left and right and a motor servo amplifier 16 for positioning the cloth feed, and drives the needle motor 17 and the cloth motor 18, respectively. These motors 17 and 18 do not rotate in a fixed direction, but reciprocate in forward and reverse directions within a certain angular range. Alternatively, the motor 18 sets the cloth feed 20 to the front or rear position depending on the output from the memory 10. The specific structure and operating principle of the sewing machine motors 17, 18 are described in the specification of Japanese Patent Application No. 144474/1983 filed by the applicant on November 30, 1978. ing. For this motor, when the drive input is zero,
It is configured to automatically return to the neutral point. The vertical movement of the needle 19 and the upward lifting of the cloth feed 20 and its subsequent movement to the central position are carried out by the main motor 1.
A cam 21 fixed to a rotating shaft, a follower 22, and arms 23, 2 pivotally connected to the follower 22.
4. It should be noted that the mechanism shown in FIG. 1 is for illustrative purposes only and is not exact. Further, in the figure, 25 and 26 indicate the fulcrums of the arms 23 and 24, respectively.

According to the electronic sewing machine having such a configuration, by storing information regarding various patterns in the memory,
After that, just select the desired pattern using the pattern selection switch and the pattern will be sewn automatically.

However, the above-mentioned conventional electronic sewing machine has the drawback that the sewn pattern may become disordered or deformed midway. As a result of various studies by the inventors, the main motor It was determined that one of the reasons for this was that the rotational speed of the engine fluctuated, disrupting the synchronization between the mechanical and electrical systems. It has also been found that, especially when a speed-controlled DC motor is used as the main motor, it is difficult to synchronize the mechanical system and the electrical system, and a significant negative effect appears at low speeds.

To improve this drawback, set the needle at the top end point, and set the cloth feed at the point where the cloth feed ratchet is slightly below the top end point, that is, when the cloth feed is completed and the ratchet is separated from the fabric. It is most preferable to do this at a specific point. In other words, there is almost no need to consider the inertia of the needle, but it is necessary to set the operating point in consideration of the inertia of the ratchet, the slip of the fabric, the slip of the DC motor, etc. At the same time, it is necessary to constantly detect out-of-synchronization between the mechanical system and the electrical system, and to control the main motor so that this out-of-sync is minimized.

However, in conventional electronic sewing machines,
Since this method controls the electric circuit system only using synchronous pulse signals obtained from the rotation of the main motor, it has not been possible to drive the electronic sewing machine in the optimum condition as described above.

The present invention has been made in view of the above points, and its purpose is to prevent the pattern from becoming disordered in the middle,
An object of the present invention is to provide a control method for an electronic sewing machine that can drive the electronic sewing machine in an optimal state so as not to cause deformation.

The electronic sewing machine control method of the present invention controls the drive of the needle motor and cloth motor in accordance with a synchronous pulse signal formed using signals generated by the rotation of the main motor and the movement of the cloth motor. It is characterized in that the rotational speed of the main motor is controlled by detecting variations in the pulse width of the synchronous pulse signal.

Hereinafter, the present invention will be explained in detail based on the attached examples.

FIG. 2 is a block diagram showing the circuit configuration of an electronic sewing machine implementing the control method of the present invention. Parts that operate substantially the same as those in the conceptual diagram shown in FIG. 1 are indicated by the same attached symbols. Although the mechanical system shown in FIG. 1 is omitted, the configuration of the mechanical system for forming stitches is the same as the conventional one. Further, the circuit configuration shown in the same figure differs from the electronic sewing machine shown in FIG. 1 only in the following points, so a description of the configuration will be omitted. That is,
The synchronizing pulse signal C supplied to the differential shaping circuits 7 and 8 is obtained from the output of an AND circuit 28 which receives output signals A and B of the main synchronizing signal generating circuit 27 and the sub synchronizing signal generating circuit 29. Further, the speed control circuit 2 is controlled via a gate circuit 31, a counting circuit 32, and a control signal generation circuit 33, which receive a synchronizing pulse signal C and a clock pulse signal of a clock pulse circuit 30 that controls the memories 9 and 10. This is what we are doing.

The main synchronization signal generation circuit 27 outputs a main synchronization signal synchronized with the rotation of the main motor 1 as an output signal A, and the sub synchronization signal generation circuit 29 outputs a main synchronization signal synchronized with the rotation of the cloth motor 18 as an output signal B. It generates a sub-synchronization signal.

The operation of the electronic sewing machine shown in FIG. 2 will be explained below. The main synchronizing signal generating circuit 27 generates a main synchronizing signal A as shown in FIG. 3A. The frequency of this signal A is determined by the rotational speed of the main motor 1, and the pulse width _T1 is set by the configuration of the generating circuit 27.

This main synchronizing signal generating circuit 27 may be constructed as shown in FIG. In the figure, 34 is a slit 3 attached to the rotating shaft 35 of the main motor 1.
4a, R ₁ is a resistor, and MR ₁ is a magnetoresistive element. A magnetic flux is applied to the element MR ₁ in advance using a permanent magnet (not shown). With this configuration, the magnetic flux applied to the element _MR1 changes in accordance with the rotation of the main motor, and a synchronization signal as shown in FIG. 3A can be obtained from the output terminal OUT1. In this case, a waveform shaping circuit such as a Schmitt circuit is provided as necessary.
Note that the pulse width can be appropriately set by changing the angle of the slit 34a.

Further, in the sub-synchronization signal generation circuit 29, the third
A sub-synchronization signal (low) as shown in figure (b) is generated.
The frequency of this signal B is determined by the rotational speed of the main motor 1 (because the cloth motor 18 is driven in synchronization with the main motor 1), and the pulse width can be set by the configuration of the generating circuit 29. Furthermore, the pulse width and falling timing of the sub-sync signal B are as follows:
It is necessary to set the optimum value in relation to the pulse width of the main synchronization signal and the optimum operating position for driving the cloth motor. This sub-synchronization signal generation circuit 29 is
It may be configured as shown in FIG. In the same figure, 36 is a magnetic body with a slit 36a formed therein, which is attached to the rotating shaft 37 of the cloth motor 18.
R ₂ is a resistor, MR ₂ is a magnetoelectric conversion element, and 38 is a monomulti circuit. In this case, the element MR ₂ needs to be accurately positioned on the center line B of the slit 36a of the magnetic body 36, taking into account that the motor 18 reciprocates in forward and reverse directions within a certain angular range. The forming angle θ of the slit 36a is determined by the cloth motor 18.
Even if the motor 18 only moves by the minimum angle set in the memory, it must be set to less than twice the minimum movement angle of the motor 18 so that the sub-synchronization signal (b) is generated. In addition, the resistance R ₂ and the element
Mono multi circuit 38 connected to the connection point of MR ₂
is a circuit that generates one negative direction pulse with a preset pulse width at the output terminal OUT2 when the magnetic flux applied to the element changes by more than a certain value, and the pulse signal output to the output terminal OUT2. is input to the AND circuit 28 as the sub-synchronizing signal B together with the main synchronizing signal A. The reason why a mono-multi circuit is used in the sub synchronization signal generation circuit 29, unlike the main synchronization signal generation circuit, is because the cloth motor 18 is different from the main motor 1, and the movement angle range changes depending on the contents of the memory 10. This is because if a monomulti circuit is not used, the pulse width will change corresponding to the movement angle, making it difficult to use as a synchronization signal.

The main synchronizing signal A and the sub-synchronizing signal B are inputted to an AND circuit 28 to form a synchronizing pulse signal C as shown in FIG. 3C.

After this synchronization signal C is differentially shaped by the differential shaping circuits 7 and 8, the memories 9 and 10 are triggered at the rising and falling timings of the synchronization signal C, respectively. Then, the needle motor 17 and cloth motor 18 are driven. That is, the trigger signals inputted to the memories 9 and 10 via the differential shaping circuits 7 and 8 and the diodes 39 and 40 are pulse signals D and E having shapes as shown in FIG. 3 D and E, respectively. Therefore, the synchronizing signal C must be a pulse set to rise at the optimum timing to operate the needle motor and fall at the optimum timing to operate the cloth motor. In other words, in the main and sub synchronization signal generation circuits 27 and 29,
This means that the respective signal pulses must be generated so that the rising edge of the main synchronizing signal A and the falling edge of the sub-syncing signal B meet the above conditions. This can be achieved by designing the configurations of the signal generating circuits 27 and 29, especially considering the positional relationship between the elements and the slits of the magnetic material. In this case, what you need to be careful about is the pulse width of the main synchronization signal A.
T ₁ needs to be longer than the time t ₂ during which the main synchronization signal A rises and the sub-synchronization signal B falls;
Furthermore, the pulse width T ₂ of the sub-synchronizing signal B needs to be longer than the time t ₁ during which the sub-synchronizing signal B falls and the main synchronizing signal A falls.

The synchronizing signal C is also input to the gate circuit 31 along with the clock pulse signal of the clock pulse circuit 30 used to control the memories 9 and 10. The gate circuit 31 outputs a clock pulse signal only during a period of pulse width _T3 of the synchronizing signal C, as shown in FIG. This output signal T is input to a counting circuit 32, which detects the number of clock pulses included in the period of pulse width _T2 . This detection signal is converted into an appropriate control signal via the control signal generation circuit 33, and then input to the speed control circuit 2, where the pulse width T ₃ of the synchronization signal C is
The main motor 1 is driven so that the value becomes a constant value.
That is, in the above circuit, a change in the pulse width _T3 of the synchronizing signal C is detected as a change in the number of clock pulses included in this period, and the rotational speed of the main motor is feedback-controlled.

As described above, according to the electronic sewing machine control method of the present invention, the following beneficial effects can be obtained.

The fabric motor is driven by a synchronous pulse signal generated from signals generated in response to the rotation of the main motor and the movement of the fabric motor itself, so it is free from ratchet inertia, fabric slip, main motor slip, etc. It is driven at the optimal operating point taking into consideration the following. Additionally, since the configuration controls the rotational speed of the main motor by detecting the phase shift between the synchronization signal obtained from the movement of the cloth motor and the synchronization signal obtained from the rotation of the main motor, there are problems with mechanical and electrical systems. The configuration is such that any synchronization deviations in the system are constantly corrected. Therefore, the drawbacks of the conventional electronic sewing machine described above are solved, and the electronic sewing machine can be operated in an optimal state so that the pattern is not disturbed or deformed on the way.

In the case of the above-mentioned embodiment, a case has been exemplified in which a magneto-electric conversion element is used as the mechanical-electric conversion means used in the synchronization signal generation circuits 27 and 29, but it goes without saying that the present invention is not limited to this. However, when a magnetoelectric transducer is used, it is convenient because it is a non-contact type that does not cause mechanical contact failure and is not affected by dust or the like.

Since the method of controlling an electronic sewing machine according to the present invention is as described above, by applying it to this type of electronic sewing machine, extremely beneficial effects in practical use can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram schematically showing an example of an electronic sewing machine, FIG. 2 is a block diagram showing a circuit configuration of an electronic sewing machine implementing the control method of the present invention, and FIG. FIG. 4 is a waveform diagram for explaining the operation of the electronic sewing machine, and FIG. 5 is a diagram showing an example of the main synchronization signal generation circuit 27 shown in FIG.
2 is a drawing showing an example of the sub-synchronization signal generation circuit 29 shown in the figure. In the figure, 1 is the main sewing machine motor, 2 is the speed control circuit, 17 is the needle left and right movement motor, 18
27 is a main synchronizing signal generating circuit, 29 is a sub synchronizing signal generating circuit, 30 is a clock pulse generating circuit, and 38 is a monomulti circuit.

Claims (1)

[Claims] 1. A motor for horizontal movement of the needle that swings the needle from side to side, a motor for positioning the cloth feed that determines the initial position of the cloth feed, and a motor for moving the needle up and down, lifting the cloth feed upward and moving it from the initial position to the center position. The three motors of the main sewing machine motor are used to drive the needle lateral movement motor and cloth feed positioning motor each time the main sewing machine motor rotates in accordance with symbols representing sewing patterns stored in memory. , in an electronic sewing machine that automatically forms a predetermined sewing pattern, the needle lateral movement motor and the cloth feed positioning motor generate signals generated by the respective movements of the main sewing machine motor and the cloth feed positioning motor. The main sewing machine motor is driven by a synchronous pulse signal outputted from an AND circuit having the synchronous pulse signal as input, and changes in the pulse width of the synchronous pulse signal are detected to control the rotational speed of the main sewing machine motor so that the synchronous pulse signal has a constant value. A method for controlling an electronic sewing machine.