JPS598997A - Needle indicating position stop control apparatus of electromotive sewing machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a needle specified position stop control device for an electric sewing machine, and more particularly to an improved needle specified position stop control device that does not cause such an operation.

Conventional needle specified position stop control devices for electric sewing machines include a needle position detection switch that detects when the needle bar is at a predetermined position, and a needle position detection switch that detects when the needle bar reaches a predetermined position when the electric machine stops The switch closes and the needle bar automatically stops at a predetermined position. However, once the needle bar has stopped at a predetermined position, if the needle bar is forcibly moved and the needle position detection switch is opened, the electric motor is driven and the needle bar moves suddenly, potentially causing danger to the worker. .

In addition, if the needle bar gets stuck in the fabric when the electric machine stops, the electric motor will continue to be energized with the needle position detection switch open, and there is a danger that the electric rD machine will overheat. there were.

It is an object of the present invention to eliminate the above-mentioned drawbacks of the prior art device, after the needle bar is stopped in a predetermined position.

To provide a needle designated position stop control device in which a needle bar is not driven even if the needle bar is moved by mistake or as required for work.

Another object of the present invention is to provide a needle designated position stop control device which automatically de-energizes the electric motor when the needle bar e' is locked while being driven.

Is this invention the following? A detailed description will be given with reference to the attached drawings. 1st
The figure is a circuit diagram of a typical example of the electric sewing machine rough side designated position stop control device according to the present invention and the speed control device of the electric motor to which it is applied, and FIGS. 2 and 6 show the operation of the speed control device of FIG. Signal waveforms of each part to explain? FIG.

In FIG. 1, reference number 2 is an AC power supply, 3 is a main switch, 4 is a DC motor, 6 is a field winding of the DC motor,
8 is the flywheel diode.

10.12 is a thyristor for controlling the energization phase of the motor current given to the DC motor from the AC power supply, 20 is a luxury diode for taking out the back electromotive force of the motor 4, 40 is a resistor for detecting back electromotive force, 48° 140 is a Motor speed setting resistor, 50 represents back electromotive force detected by resistor 40 and resistor 46
54. A linear amplifier that functions as a servo amplifier that inputs a speed indicating voltage set at , and outputs a speed indicating voltage that sets this deviation to a predetermined value (for example, zero) based on these deviations. 56 is a resistor and a capacitor for stabilizing the output of the linear amplifier to prevent disturbances in the motor;
6 is a comparator whose non-inverting input inputs a sawtooth wave voltage through a terminal 70, and 1 whose inverting input inputs the output voltage of the linear amplifier 50;

Is 80 a conduction pulse in response to the comparator's cutting edge? The generated switching element is, for example, an 8BS element, and 82 has a primary winding of BB.
It is a pulse transformer connected to the output of the S element and whose secondary winding is connected to the gate electrode of the thyristor 10.12. Here, the resistor 18 is for detecting the back motion of the motor, and the resistor 24 is connected to the output of the S element. .28.32.36-Capacitor 2
2.26 has the function of protecting the r-t of the thyristor 10.12, and the resistor 52 and the resistor 44 have a ratio determined by the resistance of the linear amplifier. It is up to you to decide.

Also, resistors 12 to 78 are resistors γ8? The divided DC voltage is divided into 2 and applied to the inverting input of the comparator 66 along with the cutting edge voltage of the linear amplifier 50, thereby applying a slight predetermined correction to the inverting input of the sharpening voltage converter where the cutting edge voltage of the linear amplifier is zero. This guarantees the conduction of the thyristor by providing a divided voltage for the thyristor. Further, the diode 88 absorbs the back electromotive force of the pulse transformer 82. Terminal 62 is a DC current signal that instructs the motor to start or stop. This is an input terminal.

The method of generating this signal will be explained in detail later.

Capacitor 56. The diode 60 starts and stops the motor χ in response to the DC current signal at the terminal 62 (the comparator 6
In addition to giving signal 2 to the 60 inverting input, the electric motor? This circuit prevents the thyristor from suddenly becoming conductive at a large energization phase when starting up.

Below is the operation of the circuit shown in Figure 1? Pier 1 dawns. First of all, electric kl
] The method for detecting the back electromotive force of machine 4 will be described. The output pulse of the pulse transformer 82 causes the thyristor 10.1
2 is energized, the output current of the AC power supply 2 is 1, as shown by the solid line in the figure. Thyristor 10. Electric g&4. Flow 11. through diode 20.16. , in the negative half cycle, the thyristor 12, the motor 4. diode 20.14
．． Then, either the current flows through the main switch 3, or it does not flow through the resistor 38.40 because of the presence of the diode 20.37.

When the motor rotates due to the energization of the thyristor, a back electromotive force is generated between the terminals 7 and 7. As shown in the illustration, the current generated by this back electromotive force flows from one end of the motor to the diode 8. Resistance 18. It flows to the other end of the motor via diode 37, resistor 3B, and 40χ.

Therefore, the voltage between the terminals of the motor 4 is as shown in FIG.
At t2), only the back electromotive force appears, and during the period when the thyristor is energized (tz to t3), the AC power supply voltage appears, but outside of the AC power supply voltage, the diode 20.37
Therefore, only a back electromotive force appears between the terminals of the resistor 40 as shown in FIG.

The voltage between the terminals of resistor 40 is applied to non-inverting input 50a of linear amplifier 50 via resistor 42.44. On the other hand, 1 inverting input 501) has DC power supply voltage + vooyr resistor 48
and the speed setting voltage divided by the resistor 46 or the resistor 44
applied via. Here, the DC power supply "vcc" is provided through the output of the AC power supply 2, the main switch 3, and a rectifier and smoothing circuit (not shown).Therefore, the amplifier 50
The cutting edge voltage becomes a voltage that is almost inversely proportional to the speed setting voltage, and is detected by the resistor 40, and varies depending on the back electromotive force, such that the smaller the back electromotive force is, the lower it becomes, and the larger the back electromotive force, the higher the value.
It outputs a voltage such that the difference between the speed setting voltage and the back electromotive force is always constant (for example, zero).
The higher the value of the speed setting voltage vs set in step 6, the faster the turtle motor rotates? It gives instructions. Also, amplifier 5
A resistor 54 and a capacitor 56 connected in parallel between the 00 inverting input 50b and the output slow down the output fluctuation when the input of the amplifier changes suddenly, thereby preventing the motor from malfunctioning.

Now, assuming that the DC power supply voltage is at the terminal 62, the output voltage of the amplifier is the correction voltage V given through the resistor γ4. is applied to the inverting input of the comparator 660 as a speed instruction voltage, and is compared with the sawtooth wave voltage (FIG. 6 (b)) applied from the terminal 70 to the non-inverting input via the resistor 68. . The phase of this sawtooth wave voltage is the cutting edge voltage (
This is synchronized with each half cycle of FIG. 6(a)). Also.

If the speed instruction voltage nV is the sum of the output pressure of the amplifier 500 and the correction rolling pressure, then v8 is V. and the maximum value vIn of the sawtooth voltage. When the value of the sawtooth wave voltage reaches the speed instruction voltage Va (Fig. 6 (-
1) At that time (time 11), a signal is output, and the SBS element 80 conducts in response to the output signal, and the pulse transformer 82
A sharp pulse-like current flows through the primary winding. Therefore, a pulse signal is induced in the secondary winding, and a pulse signal is applied as a signal to each date of the thyristor 10.12 through the diode 30.34 and the resistor 32.36, thereby energizing each thyristor (
)). Therefore, if the main switch 3 is turned on, the thyristor is energized at a conduction angle determined by the speed instruction voltage va, and the electric motor operates at a predetermined speed.

By changing the set value 2 of either of the resistors 46, 48, 140, the speed command voltage VaY can be set to any value between the minimum value v0 and the maximum value vI]1, and the motor speed can be adjusted to any desired speed. can do.

The operation of stopping the starting tube of the electric motor will be briefly explained.

Now, assuming that a DC current of a predetermined value is input to the terminal 62, which instructs the terminal 62 to stop, the capacitor 56 is charged and the terminal voltage is applied to the inverting input of the comparator 660 through the resistor 72, so that the voltage at the inverting input is Since the voltage exceeds the maximum value of the non-inverting input, the comparator does not output a pulse signal and the motor is not driven. When a DC current indicating start-up, that is, a signal with a current value of zero, is applied from the terminal 62, the capacitor 56 is not charged and only the speed instruction voltage V is applied to the comparator 66.
The voltage at the zero inverting input is less than the maximum value of the voltage at the non-inverting input and the motor is started and driven at a speed determined by the values of resistors 46 and 48 DEG 140.

While the motor is being operated at a speed determined by the speed setting voltage vs determined by the resistors 46, 48, and 140 in this manner, describe a case where the rotational speed of the motor fluctuates due to changes in load or the like.

Now, suppose the load increases and the rotational speed decreases.

Since the back motion of the motor decreases and the voltage across the terminals of the resistor 40 decreases, the blade voltage of the amplifier 50 decreases and the speed command voltage v
a also decreases. Therefore, the energization phase of the thyristor advances, and the rotation speed of the motor increases to maintain the speed determined by the speed setting voltage v8. Also, when the load decreases and the rotational speed increases.

Since the back electromotive force increases, the output torque of the amplifier 500 increases, and the speed instruction voltage Va also increases. Therefore, the energization phase of the thyristor is delayed, and the rotational speed of the motor is reduced and maintained at the original rotational speed.

In this way, even if the rotational speed of the motor fluctuates due to changes in the load or power supply voltage, it is detected by the counter electromotive force and negative feedback control is performed so that the one rotational speed is always maintained at the speed determined by the speed setting voltage v8. It can be maintained stably.

Moreover, in the present invention, electricity! The signal indicating the speed of the EII machine does not use the rotary generator's blade signal. An inexpensive speed control device can be provided.

By the way, when starting the motor, the voltage input to the non-inverting input 50a is small compared to the speed setting voltage 8 determined by the resistor 48 until the motor rotation speed reaches the desired set rotation speed, so the output of the amplifier 5o Because the voltage is small and the speed indication voltage■ is also small.

There is a risk that the thyristor will be energized at an extremely early phase, causing a large current to flow to the motor and causing it to be driven rapidly.

To prevent this, resistor 54. capacitor 5
6. Diode 60. A circuit consisting of is added.

Next, the operation of this circuit will be explained.

First, when the main switch 3 is closed while the switch 101 is open, the Nantes gate 104 applies the DC power +■oo to the human power f from the terminal 114 through the resistor 102, but the input e This is because a signal of f) below the high level is applied from the NAND date 120.

Its output remains at low level (hereinafter referred to as L level),
Therefore, the H level output inverted by the inverter 106 is transmitted to the resistor 108. The diode 110° is connected to the terminal 62, and the resistor 74.7 is used as the voltage that instructs the motor to stop.
6 in series circuit.

This terminal voltage is applied to the inverting input of comparator 660 via resistor 72. Since this voltage is greater than the maximum value v[n of the sawtooth wave voltage applied to the non-inverting input, the comparator 66 does not output. Always keep the motor in a stopped state.

At this time, the capacitor 56 is charged by the DC current applied via the terminal 62.

When the operation switch 101 is closed, the input f of the NAND date 104 becomes L level, so the output becomes H level. Therefore, the output of the inverter 106 becomes L level, and the current flowing from the terminal 62 to the resistor 74.76 through the resistor 108 is cut off, so that the potential of the inverting input of the comparator 66 decreases. On the other hand, since the capacitor 560 charge is discharged through the resistor 74, 76, 54 yr, the terminal voltage begins to gradually decrease. Therefore, the speed instruction voltage va begins to gradually decrease from the maximum value vIn, the thyristor is energized at a small conduction angle, and the acid moving rock is slowly started and increases to a predetermined rotational speed. In this way, the plunge rotation of the ton machine is prevented.

Regarding the needle specified position stop control device 100 according to the present invention, which, when applied to a sewing machine with such a speed side [phase] device of an electric motor, stops the needle bar accurately at a predetermined needle position and prevents the above-mentioned malfunction. explain.

In FIG. 1, the switch 101 instructs the motor 4 to stop and start depending on its open and closed states, and the motor is started by closing the switch 101Y while the main switch 3 is closed. Ru. 122
is a known needle position detection switch that is closed when the needle bar reaches a predetermined position, for example, the top dead center, and is opened when the needle bar leaves the top dead center. The Nanddate 104.118.120 is a well-known C-MOEI type logic integrated circuit.

First, a state in which the electric motor is stopped will be explained.

As long as the switch 101 is open, the DC voltage +voo applied to the terminal 114 is kept at the fiH level of the input of the NAND r-1104, and the human power θ is also kept at the H level.

The output of the NAND date 104 becomes L level, which is inverted by the inverter 106, and the -H level output is given to the terminal 62 or resistor 74.76 via the resistor 108 and diode 110, so the inverted input level of the comparator 66 is non-zero. Since the inverting input level becomes higher than the maximum value - and the comparator 66 does not generate an output limit signal, the thyristors 10 and 12 are non-conducting and the motor remains stopped. At this time, the capacitor 116 is charged to KP due to the H level output of the inverter 106.
Therefore, the input a and the input of the NAND date 118 are both at H level, and the cutting edge thereof is at L level. On the other hand, the input d of Nando Day) 120 is.

Since the output of the inverter 124 is at the L level, the capacitor 128 is at the L level after being charged.

Therefore, both the inputs c and dl of the NAND r-) 120 are at L level, and the output thereof is at H level.

Incidentally, the 1-signal waveforms of each part of the needle designated position stop control device 100 are as shown in FIG.

The starting of the low VL electric motor will be explained.

Ki 11 [IJ'a? When the switch 101 is closed to give an instruction, the input f of the NAND date 1040 becomes L level and the output of NAND date 104 becomes H level regardless of the human power e, so the output inverted by the inverter 106 becomes L level. The charge in the capacitor 116 is discharged through the diodes 117, resulting in a 118 (1) input cover.

b are both at KL level and their blades are at H level. On the other hand, until now the resistance was 108. The current instructing stop flowing through the diode 110 to the terminal 62 is cut off, so the charge stored in the capacitor 56 is gradually discharged through the resistor 74.76x, and the potential of the inverting input of the comparator 66 gradually decreases. , and becomes below the maximum value Vm of the sawtooth wave applied to the non-inverting input, so the comparator starts outputting a pulse signal at a slow phase of half a cycle of the AC power supply, and the thyristor 10.
The electric motor is started by applying current at a small conduction angle of 20 degrees.

On the other hand, due to the switch 101 being closed.

Since the input of the inverter 124 becomes L level.

The output of the inverter 124 becomes H level, and the diode 132. Terminal 134. Since current flows through the resistor 46 via the resistor 140, the speed setting voltage v1. 1llill depending on l? The rotational speed of the electric motor increases to the full speed, and the electric motor continues to rotate two times while maintaining this speed. By varying the resistance value of the resistor 140 in this state, the motor can be set to a desired rotation speed. Also, by closing the switch 101, the inverter 12
The H level blade of 4 is a diode 125. A capacitor 128 is charged through a resistor 126 and continues to be charged while the motor is rotating. Therefore, the Nandt gate 1200Å force d is H
This is because the needle bar is at the L level only while the needle bar is at the top dead center Y and the switch 122 is closed (for example, between times t9 and t3) (FIG. 4 (1)).

The output becomes H level as shown in FIG. 4 (1).

The input f of NAND/F'-) 104 is maintained at L level.'
Therefore, the blade is kept at H level (Fig. 4(d)).

The operation of stopping a rotating electric motor will be briefly explained.

As mentioned above, when the electric motor continues to rotate at a constant speed, the switch 101'F! indicates stop YEN! :: When released at time tA, Nando date 1040 enters 7Jf &
Since the power of the inverter 1240 changes from the L level to the H level, the output of the inverter 1240 becomes the L level, and the diode 132. The speed setting voltage applied to the resistor 140 through the terminal 134 is no longer present, and the speed setting voltage v
s is a voltage constantly applied to the resistor 48 from the power supply +voo.

That is, since the electric sewing machine only needs voltage to rotate at a low speed with no inertia, the speed of the electric motor begins to decrease and eventually rotates at a low speed with no inertia.

Furthermore, since the output of inverter 124 becomes L level, diode 125. Since the charging current that was being applied to the capacitor 128 through the resistor 126 is cut off, the charge that has been stored in the capacitor 128 is transferred to the resistors 130 and 126.
31, the voltage is gradually discharged, and the voltage generated at the resistor 131 at the 7j terminal continues to be maintained at the input diH level of the system 120. Also, human power C is also Nando r
-) 1H when both 1180 inputs a and b are at L level
Since it remains at the level, the output of the Nando date 120 continues L reperun. Therefore, even if the NAND r-) 1040 input f goes to H level due to the opening of the switch 101, the NAND date 104's blade will remain at H level 2, and the L level blade of BATA 106 will continue to instruct the user to start. Therefore, the electric motor continues to rotate at the above-mentioned speed without inertia.

Further, the electric motor continues to rotate 1. For example, the needle position detection switch 122 provided at the top dead center closes at time t5, and the resistor 13
When 1 is short-circuited, the Nand gate 1200 Å force d becomes L level, so the Nand ke 9-) 1200 deba changes to H level, and both Nand date 1040 two large forces become H level. Therefore, the output of NAND DATE 104 changes to L level.

The resistance of the H level mountain blade that has been completely reversed by the inverter 106 is 10.
B, the motor tries to stop because the current flowing through the diode 110 at terminal 62Vc stops.

At this time, the H level of the inverter 106 immediately changes the input aY of the NAND gate 11B to the H level, and at the same time starts charging the capacitor 116 via the resistor 112. r-) 118 manpower.

By the time the predetermined threshold voltage (corresponding to H level) is reached,
Time constant τ2 determined by capacitor 116 and resistor 112? (Fig. 4(f)), so the period is τ2.

If the output of the inverter 106 continues to be at H level, both of the two large forces of NAND date 118 will be at H level, and NAND r-) 1200Å sword 2C will be at H level or l.
It will change to pL level. However, in this case 'Kame vJ
The speed of the aircraft has decreased significantly.

The d position detection switch 122 opens again at time t6, which is a time τ shorter than τ2. Therefore, Nandoke”
-) The input d of 120 becomes H level again at time t6, and the input θ of NAND DATE 1040 becomes L level again, so the output of NAND DATE 104 changes to H level, the blade of inverter 106 is reversed to L level, and the motor is turned on again. At the same time as the start-up instruction is given, the discharge occurs through the discharge diode 117 stored in the capacitor 116.

Here, the time constant 2 is sufficiently larger than τ1, so it may be
After the electric sewing machine has completely stopped, before the operator of the electric sewing machine tries to move the nail position, the capacitor 11
6 is preset to a value that allows the output YL level of the NAND date 118 to be changed after charging is completed.

'R1, the motor continues to rotate, and when it is sufficiently decelerated, the needle position detection switch 122 is closed again at time 1, a current is applied to the terminal 62 to instruct the stop, and the cyrisk 10.12 becomes non-conductive, and the motor immediately stops. Therefore, the switch 122 remains closed without being opened again.

Therefore, the Nandt date 1200 Å force d becomes L level, and the inputs e and f of the Nant gate 104 both become H level.
A current is applied to the terminal 62 through the eight diode 110', and at the same time is applied to the capacitor 116 through the resistor 112. Therefore, at time t8, which is 72 hours after time t7, the Nando date 1180 power reaches the H level, and the blade becomes the L level.

The L level is input to the input C of the -ty date 120. Therefore, Nando date 1200 human power c and d are both L
level.

If a worker operates the sewing machine in this state to forcefully move the needle position and open the needle position detection switch 122, the capacitor 128 will transfer the residual charge through the resistors 130 and 131. Since it is discharging, the input d of the NAND r-) 120 changes to H level. However, since the human power C of NAND DATE 1200 is at L level, the blade of NAND DATE 120 maintains H level 2, so the operating state of NAND DATE 104 does not change, and therefore the inverter 1
The 060 output continues to be held at H level, which indicates whether or not to stop.

In this way, once the electric motor has stopped, there is no risk of it restarting even if the needle position is moved artificially, and it can be moved freely by a cow to change it to a desired position at any time.

Incidentally, the potential of the capacitor 128 is changed at time t4 when the discharge of tv starts.
Therefore, τ, which is determined by the capacitance of the capacitor 128 and the values of the resistors 130 and 131, becomes less than the IMI value level (H level) of the Nandt gate 120 at time t0° after 3 hours have elapsed.

The operation of stopping the electric motor when the IMI rod becomes stuck and becomes locked and does not move will now be explained.

Stop the rotating electric motor (start switch 101vt)
When J is released, the charge on the capacitor 128 is transferred to the resistor 130.
, 131, a terminal voltage is generated across the resistor 131 by the discharge current of the capacitor 128, and the input d'a? of the NAND date 120 is generated. , keep it at H level. In this state, the needle bar reaches the top dead center, resulting in resistance of 13
When the needle position detection switch 122 connected in parallel with the needle position detecting switch 122 is closed, the electric needle stops. However, what happens if the needle bar locks before it reaches the position where the 11 position detection switch 122 closes (top dead center)?

Since the switch 122 remains open, the
Input d of 4120 remains at H level.

Also, since the human power C is at the H level, the output is kept at the L level, and therefore the output of the NAND date 104 is kept at the H level, so no signal is output to instruct the motor to stop.
゛Let the electric motor 1 continue to rotate further 5 and the starting state χ
Continue to maintain. However, when the start switch 101 is opened, charging of the capacitor 128 is stopped, so the charge that has been stored up to now is transferred to the resistor 130. L
31x, and eventually, after a predetermined time τ3, the terminal voltage of the resistor 131 reaches the input d of the NAND date 120.
When the voltage drops below the threshold voltage, the input to the Nant gate 120 goes to L level.9. Since an H level signal is applied to the input e of the NAND DATE 104, the NAND DATE 104 outputs an L level. Therefore, the L level output of the Nandoku °''-) 104 can be inverted by the inverter 106, and the H level output of the resistor 104 is inverted.
A current indicating stop is applied to terminal 62 through the 8° diode 110, so that the motor immediately stops.

In this way switch 101'i:! 0: If released, even if the needle bar is locked, the supply to the electric motor will be automatically cut off after a predetermined period of time, which will prevent the risk of overheating the tun wj machine. The needle position stop control device for a moving sewing machine according to the present invention prevents the dangerous situation in which the electric kJJ machine is driven and the needle bar moves even if the needle bar is accidentally moved after it has stopped at a predetermined position.

If the pull rod locks after opening switch 101,
Alternatively, if the switch 101 is opened after the needle bar is locked, the supply current to the motor is automatically cut off after a predetermined period of time, thereby preventing the motor from overheating.

The needle position stop control device according to the present invention can be applied not only to the motor speed control circuit shown in FIG. 1, but also to other types of speed control circuits.

[Brief explanation of drawings]

FIG. 1 shows a needle designated position stop control device for a 'NL moving sewing machine and Jf:t'1. Figures 2, 6, and 4 are circuit diagrams of typical examples of speed control devices for DC motors to which the speed control device shown in Figure 1 is applied. A time chart showing waveforms.・Explanation of symbols 2... AC power supply, 3... Main switch, 4...
DC electric vJ machine, 50... linear amplifier, 66... comparator. 80... BBB element, 82... Pulse transformer. 122...Needle position detection switch. Representatives: Akira Asamura, 4 people (Fig. 1, Fig. 2), Fig. 3

Claims (1)

[Claims] (1) A main motor circuit that supplies motor current from the AC power source (2) to the DC motor (4) via the main switch (3), the semiconductor means with control electrodes (10, 12), and the semiconductor means, and energizes the semiconductor means. A trigger for outputting a trigger signal for phase control is a signal generating means (66), and a speed instruction signal generator which is activated by closing of the main switch and gives a signal to the trigger signal generating means to instruct the rotational speed of the electric motor. (46
4B, 50.140), a switch means (101) which is switched between a first state for instructing the electric motor to start and a second state for instructing it to stop; first bias signal generating means (104 and 106) for generating a first bias signal instructing the signal generating means to stop the electric motor; and a second bias signal for generating the trigger No. 1g generating means connected to the switch means; A second bias signal generating means (124) is connected to the output of the first bias signal generating means and the output is connected to the first and second bias signal generating means.
a first logic means (11B) that changes between states; a charging/discharging element (128) connected to the output of the bias signal generating means; An input is connected to a needle position detection switch (122) that closes when detecting a noise, and an output of the first logic means and the photodischarge element, and the output changes between a first and second state. With the second logical means (120)? Be prepared. The first bias signal generating means is configured such that the switch means is in a second state and the output of the second logic means is in a first state.
A first bias signal is generated only when the trigger signal is in the state, and is applied to the trigger signal generating means, and when the trigger signal stops, the first bias signal is applied to the first logic means. The first logic means changes its output from a first state to a second state in response to the first bias signal. The second bias signal generating means generates the second bias signal 2 when the switch means is in the first state, and applies the second bias signal 2 to the speed instruction signal generator and to the charging/discharging element to charge the element. Turtle. When the speed instruction signal generation means receives a second bias signal from the second bias signal generation means, it generates a speed instruction signal Y that instructs normal operation, and when the second bias signal is not applied, it generates a speed instruction signal Y that instructs low speed rotation. Instruction signal? Occurred. The charge/discharge element applies a sixth bias signal to the second logic means while the second bias signal is applied and for a predetermined time after the second bias signal is cut off. When the needle position detection switch is closed, the sixth bias signal is invalidated; and the second logic means is configured to disable the sixth bias signal when the output of the first logic means is in the first state and the sixth bias signal is applied. A specified position stop control device on the barrel side of an electric sewing machine, characterized in that only the output is in the second state and the other outputs are in the first state. (2. In Claim 1, the first logic means has a charging/discharging element (116) connected to the output of the first bias signal generating means, and the first logic means A specified needle position for an electric sewing machine, characterized in that when a bias signal is applied, the output changes from a first state to a second state after a predetermined time, and returns to the first state when the first bias signal is no longer applied. Stop control device.