JPS5953072B2 - Solenoid sewing machine Solenoid Solenoid sewing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a solenoid operation selection device for an electric sewing machine, and in particular, it is capable of selectively activating an electromagnetic solenoid for controlling the drive of a sewing machine, and controlling the operation of the solenoid. This relates to an electric sewing machine that can be operated by pressing a controller, and its purpose is to control the sewing machine motor in two speed modes, low speed and high speed, when the solenoid is set to an inactive state. In addition, when the solenoid is set to the operating state, the speed of the sewing machine motor can be controlled only at relatively low speeds, and the energization of the electromagnetic solenoid by pressing the controller requires a separate switch means. To provide a device which can process a cord connected to a sewing machine in exactly the same way as a conventional sewing machine which does not use a solenoid, even though an electromagnetic solenoid is used.

Examples shown in three sections will be described below.

First, referring to Figures 1 and 2, 1 is the sewing machine frame 2.
A main shaft 3 is supported by a pulley into which a shaft cylinder 4 is inserted, which is connected to a sewing machine motor via a belt 5 and rotated together with the shaft cylinder 4 around the main shaft 1.

Reference numeral 6 denotes a second shaft cylinder adjacent to the shaft cylinder 4, which is inserted and fixed to the main shaft 1, and has an outer diameter substantially equal to that of the shaft cylinder 4.

Reference numeral 7 denotes a cylindrical helical spring tightly wound around both shaft cylinders 4.6, and one end 7a located on the first shaft cylinder 4 side is erected radially outward. The other end 7b is locked in a cut groove 6a bored in the second cylindrical cylinder 6.

Therefore, the rotation of the pulley 3 is always caused by the rotation of the first shaft cylinder 4,
It is transmitted to the main shaft 1 via the helical spring 7 and the second shaft cylinder 6, but when one end 7a of the helical spring 7 is locked by some means, the helical spring 7 is relaxed and the pulley 3 The rotation of Ic is not transmitted to the main shaft 1, and moreover, the main shaft 1 is stopped, and the spiral spring 7 acts as a clutch spring and also serves as a stopping member connected to the main shaft 1.

Note that 9 is a handwheel fixed to the main shaft 1 with a fixing screw 10, and 11 is a retaining ring for regulating the axial movement of the pulley 3.

On the other hand, reference numeral 12 denotes a stop lever which is pivotally connected to a support plate 13 fixed to the sewing machine frame 2 by a stepped screw 4, and one arm of which can engage with an engaging portion 8a formed in the sleeve 8. A contact portion 12a positioned as shown in FIG. A guide portion 12d having a new music stepped portion 12C for guiding is formed.

Reference numeral 15 denotes a tension spring stretched between the stop lever 12 and the support plate 13;
a is positioned on the rotation locus of the engaging portion 8a.

When the abutting portion 12a of the stop lever 12 engages with the engaging portion 8a of the sleeve 8, one end 7a of the helical spring 7 is locked, and the main shaft 1 is stopped, the tip of the thread take-up of the sewing machine is The position of the engaging portion 8a is set to be approximately at the uppermost position, and therefore, the needle bar that supports the sewing machine needle at the lower end stops when it reaches a position slightly lower than the uppermost position.

16 is a mounting plate fixed to the sewing machine frame 2 with screws 17 and 17, and 18 is a screw 1 attached to the bent portion 16a of the mounting plate 16.
9. The electromagnetic solenoid 19 is fixed, and the solenoid 20 is connected to the solenoid 1 through a synthetic resin plate 21 (see Fig. 3).
The synthetic resin plate 21 is fixed so as to move together with the intermediate lever 20, and serves as a magnetic insulating plate.

Further, the intermediate portion of the intermediate lever 20 is provided with the stop lever 1.
A claw portion 20a that can be engaged with the engaging portion 12b of the intermediate lever 20 is formed, and the distal end portion of the intermediate lever 20 engages with the engaging portion 12b of the stop lever 12.
It extends to face the side arm of.

23 is a tension spring stretched between the intermediate lever 20 and the support plate 13;
As is clear from FIG.
It is located on the left side of the line connecting the locking point with the plunger 18a and the center point of the pivot shaft 22, and always urges the intermediate lever 20 upward and rotates around the pivot point with the plunger 18a. It provides rotational force in the direction.

Therefore, one side edge 20b of the intermediate lever 20 engages with the side edge of the bent step 12C of the stop lever 12, and the movement of the intermediate lever 20 is guided.

Further, the guide portion 12d of the stop lever 12 is connected to the intermediate lever 2.
It faces the front end 20C of the intermediate lever 20 from the front in FIG. 1, and restricts the forward movement of the front end of the intermediate lever 20.

Further, 24 is a second support plate fixed to the sewing machine frame 2 by the spring bolts 25 and 25 and the screws 17, and 26 is a step screw 27.
A switching lever 28 is pivotally connected to the support plate 24 and has one end facing a bent portion 12e formed in one arm of the stop lever 12, and a switching lever 28 has one side edge facing the other end of the switching lever 26. The operating lever is pivotally mounted to the support plate 24 by a step screw 29, and one arm thereof is formed with an abutting portion 28a that faces an operating protrusion 30a of the changeover switch 30 fixed to the mounting plate 16.

Reference numeral 31 denotes a tension spring stretched between the switching lever 26 and the support plate 24, which has a larger spring force than the spring 15, and which causes the switching lever 26 to move clockwise in FIG. It gives a turning force.

Next, referring to FIGS. 2 and 4, reference numeral 32 is a linking lever pivotally connected to the support plate 24 by a shoulder screw 33, and one end of which engages with the extending portion 28b of the operating lever 28; An operating lever is pivotally connected to the sewing machine frame 2 by a screw 35, and has a pin 3 at one end that engages with the other end of the linking lever 32.
6 is implanted, and the other end is positioned so as to come into contact with an operating pin, which will be described later. A rotational force is applied to the sewing machine (clockwise in FIG. 4), and one edge of the sewing machine comes into contact with a stopper pin 40 implanted in the sewing machine frame 2, so that the sewing machine remains stationary.

Reference numeral 37 denotes a manual operation knob located on the front surface of the sewing machine frame 2 and mounted on the machine frame so as to be able to rotate around the support shaft 38. On the back side thereof, there is a cam surface 39a for adjusting the zigzag amplitude. A cam groove 39 having a cam surface 39b and a cam surface 39b for setting and maintaining the zigzag amplitude at zero is bored.

Reference numeral 41 denotes an operating pin implanted on the back side of the manual operation knob 37, and the operation knob is rotated counterclockwise (in FIG. 2).
It is positioned so that it can come into contact with the operating lever 34 when it is rotated clockwise in FIG.

Reference numeral 42 denotes a driven arm pivotally connected to the sewing machine frame 2 by a stepped screw 43. A driven pin 44 that fits into the cam groove 39 is implanted in the middle part of the driven arm, and a long hole 42a is bored in the tip part. has been done.

Reference numeral 45 denotes a rotating arm that is fitted and supported on the support shaft 38, and a linking pin 46 that fits into the elongated hole 42a of the driven arm 42 is implanted in the middle part of the rotating arm. A rotational force in the counterclockwise direction in FIG. 2 is applied by the action of a coiled spring 47 wound around.

Therefore, the driven arm 42 is also urged in the same direction and the driven pin 4
4 engages with the cams m39a and 39b of the cam groove 39.

48 is a zigzag connecting rod whose lower end is connected to the rotating arm 45, and the tip thereof can change the position of a roller that engages with a zigzag swinging arm (not shown), as is well known. It is linked to the corresponding roller.

Further, in FIG. 4, reference numeral 49 denotes an elastic plate fixed to the sewing machine frame 2 by a fixing screw 50, and the bent end portion 49
a is a notch 3 formed on the outer peripheral surface of the operating knob 37;
7a to 37C to position the knob 37.

In addition, in FIG. 2, 51 is a cover.

Next, the electric circuit and its specific wiring in this embodiment will be explained with reference to FIGS. 5 and 8.

In the figure, reference numerals 52 and 53 are power supply terminals connected to an AC power supply via plugs, and between these terminals a diode 54 of the polarity shown, a sewing machine motor 55 consisting of a field winding 55F and an armature winding 55A are connected. , and a controller 57 including a variable resistor 56 for controlling current to the motor and speed of the motor are connected in series to form a motor drive circuit.

When the controller 57 is pressed, the slider 56a moves in contact with the variable resistor 56.

Further, 58 is a manually operated switch for shorting the diode 54, and is connected in parallel to the diode 54 via the changeover switch 30 to form a short circuit.

Further, the AC input terminal of the bridge rectifier 59, between which the electromagnetic solenoid 18 described above is connected between the output terminals, is connected in parallel to the series circuit of the diode 54 and the sewing machine motor 55 via a changeover switch 30, so that the solenoid is actuated. It constitutes a circuit.

Accordingly, the changeover switch 30 can be switched to selectively enable the short circuit and the solenoid operated circuit.

Further, 60 is a lamp connected between the power supply terminals via a manual switch 61.

Incidentally, FIG. 8 shows an example of the wiring diagram of the circuit shown in FIG. 5, and 62 is an insulating substrate fixed to the sewing machine frame 2, and the diode 54 and the bridge rectifier 59 are arranged on this substrate. has been done.

Further, 63 indicates a connecting portion, and each element shown to the right of this portion is arranged within the sewing machine frame.

Further, the manual operation switch 58 and the manual switch 61 can be opened and closed at appropriate locations on the sewing machine frame 2 from outside the sewing machine frame.

Next, the operation mode of the above embodiment device will be explained.

1 to 5 show the positional relationship of each member when the sewing machine is set to the normal continuous sewing state, and the switching lever 26 is moved clockwise to the maximum in FIG. 1 by the action of the tension spring 31. The spring 1 is rotated to pull the stop lever 12.
5 in the counterclockwise direction in the figure, and the operating lever 28 is rotated counterclockwise to the maximum.

Therefore, the contact portion 12a of the stop lever 12 is located outside the rotation locus of the engagement portion 8a of the sleeve 8, and the contact portion 28a of the operating lever 28 is separated from the operating protrusion 30a of the changeover switch 30, As shown in FIG. 5, the movable contact a and the fixed contact A of the changeover switch 30 are closed.

When the controller is pressed in this state, the slider 56a
is connected to a variable resistor 56, power is supplied to the sewing machine motor 55 to start the motor, and the slider 56a slides on the variable resistor 56 depending on the degree of pressure from the controller thereafter. The rotational speed of the motor 55 is controlled by changing the resistance value of the motor.

At this time, since the aforementioned changeover switch 30 opens the fixed contact C side, the electromagnetic solenoid 18 is not energized.

When the motor 55 is started, the pulley 3 rotates together with the shaft tube 4 via the belt 5, and this rotation tightens the helical spring 7, which wraps around both shaft tubes 4 and 6, causing the pulley 3 to rotate. The rotation of the main shaft is transmitted to the main shaft 1, and the main shaft starts.

Thereafter, the rotational speed of the main spindle 1 is arbitrarily adjusted according to the degree of pressure applied by the controller, and normal continuous sewing is performed.

At this time, the sleeve 8 fitted around the helical spring 7 also rotates together with the main shaft 1 together with the spring 7, but the abutment part 12a of the stop lever 12 Since it is located outside the trajectory, it does not pose any hindrance to continuous sewing.

Further, the zigzag amplitude during continuous sewing can be arbitrarily set by rotating the manual operation knob 37.

That is, FIG. 2 shows a state in which the zigzag amplitude is set to zero, and from this state, if the operating knob 37 is rotated clockwise (counterclockwise in FIG. 4), the cam groove 39 will be rotated. Zigzag amplitude adjustment cam surface 39a and driven pin 4
4, the driven arm 42 rotates, and the rotating arm 45 is rotated clockwise in FIG. 2 against the action of the coil spring 47. A desired zigzag amplitude can be obtained by arbitrarily setting the position of the roller relative to the swinging fulcrum of the moving arm.

Note that when the pressure on the controller I roller 57 is released, the slider 56a separates from the variable resistor 56 and the power to the electric motor 55 is cut off, preventing the main shaft of the sewing machine from stopping at the normal position. Same as before.

Further, as shown in FIG. 5, when the manual operation switch 58 is closed, the diode 54 shown in FIG. At this time, a half-wave rectified DC voltage is applied to the motor.

Therefore, when the manual operation switch 58 is closed, the electric power supplied to the motor increases compared to when the switch is opened, and the rotational speed thereof increases.

This allows speed control in two modes, high speed and low speed, despite the same degree of pressure on the controller.

Next, a case in which basting stitches are performed will be explained.

First, prior to pressing the controller 58, the bent end portion 49a of the elastic plate 49 in FIG.
If the operating knob 37 is rotated clockwise in the figure (counterclockwise in FIG. 2) so as to fit into the notch 37C, the operating pin 4 implanted in the knob 37 will be turned.
1 comes into contact with the operating lever 34 and rotates the lever 34 from the solid line position to the two-dot chain line position in FIG.

Therefore, the linking lever 32 is rotated to the two-dot chain line position in the figure, and the operating lever 28 is moved from the position shown in FIG. 1 to the sixth position.
Rotate to the position shown in the figure and push the actuating protrusion 30a of the changeover switch 30 with the abutting portion 28a.
The movable contact a and the fixed contact C are switched to be closed, and the switching lever 26 is rotated against the action of the puller 3].

Due to this rotation, the stop lever 12 is rotated by the action of the tension spring 15, and its contact portion 12a moves onto the rotation locus of the engagement portion 8a of the sleeve 8, and lightly touches the outer peripheral surface of the sleeve 8. Stand still in contact.

FIG. 6 shows the positional relationship of each member when the manual operation knob 37 is rotated to the basting position.

On the other hand, by rotating the manual operation knob 37 in the counterclockwise direction in FIG.
is located in the state shown in FIG. 2, the rollers are aligned with the swinging fulcrum of the zigzag swinging arm via the zigzag connecting rod 48, and the zigzag amplitude is set and maintained at zero.

Therefore, even when the sewing machine is operated, the needle bar does not swing.

Therefore, the operating mode of basting stitching will be explained with reference to FIGS. 5 to 8.

When the controller 57 is pressed in the above state, the sewing machine motor 55 is energized as in the case of the continuous line described above, and the switch 30 is connected between the movable contact a and the fixed contact C. The electromagnetic solenoid 18 is energized.

Therefore, the solenoid 18 is activated immediately and its plunger 18a is sucked downward in FIGS. 6 and 7, thereby causing the intermediate lever 20 to
The claw portion 2 moves against the action of the tension spring 23.
0a and the engaging portion 12b of the stop lever 12, the lever 12 is rotated around the step screw 14 against the action of the tension spring 15.

Due to this rotation, the abutting portion 12a of the stop lever 12 moves out of the rotational trajectory of the engaging portion 8a of the sleeve 8.

On the other hand, power is supplied to the sewing machine motor 55 to start the motor 55, the pulley 3 rotates together with the shaft cylinder 4 via the belt 5, and the main shaft 1 is started by tightening the helical spring 7.

At this time, if the abutting portion 12a of the stop lever 12 and the engaging portion 8a of the sleeve 8 are engaged, one end 7 of the helical spring 7
a is locked, the spring 7 is not tightened and the pulley 3 idles around the main shaft 1. However, when the stop lever 12 moves out of the rotation locus of the engaging portion 8a, the helical spring 7 is tightened. Spindle 1 starts.

When the stop lever 12 rotates due to the downward movement of the intermediate lever 20, the bent step 12C presses one side edge 201 of the intermediate lever 20, and the intermediate lever 20
0 around the axis 22.

Therefore, the intermediate lever 20 is rotated while moving downward, and the movement locus of the tip of the claw portion 20a is a curve 11 shown in FIG. 7, while the stop lever 12
Since the locus of movement of the left end of the engaging portion 12b is an arc 2 centered on the axis of the step screw 14, the claw portion 20a of the intermediate lever 20, which is moved by the attraction of the plunger 18a, moves along both loci 11 and 12. When moving downward from the intersection point P, the engagement with the engaging portion 12b is disengaged, and the stop lever 12 is rotated by the action of the spring 15 despite the subsequent downward movement of the intermediate lever 20. Then, the abutting portion 12a returns to the position on the rotation locus of the engaging portion 8a.

As a result, the engaging portion 8a of the sleeve 8 rotating together with the main shaft 1 comes into contact with the abutting portion 12a of the stop lever 12, relaxing the helical spring 7 and disengaging the driving connection between the pulley 3 and the main shaft 1. , the main shaft 1 is stopped with the balance at the uppermost position.

However, the pulley 3 idles around the main shaft 1 until the pressure from the controller is released, and the electromagnetic solenoid 18 is also in the operating state, and the intermediate lever 20 is held at the lowest position. The part 20a is the stop lever 1
It is located below the second engaging portion 12b.

If the controller 57 is released from the pressure, the electromagnetic solenoid 18 is de-energized and the plunger 1
8a and the intermediate lever 20 are returned to the original position shown in FIG. 6 by the action of the spring 23.

At that time, the claw portion 20a is attached to the engaging portion 12 of the stop lever 12.
It is clear that b can be easily overcome.

In short, when the controller 58 is pressed, the stop lever 12 rotates against the action of the spring 15, and its abutting portion 12a once moves out of the rotation locus of the engaging portion 8a, and when it moves, The main shaft 1 of the sewing machine is started, and then the stop lever 12 is rotated back due to the action of the tension spring 15 despite the continuation of the pressing operation of the controller 58, and its abutting portion 12a is rotated along the rotational trajectory of the engaging portion 8a. located above.

As a result, when the main spindle 1 rotates substantially, the engaging portion 8a comes into contact with the contact portion 12a of the stop lever 12 to stop the main spindle 1. At this time, the thread take-up lever is at the substantially uppermost position, and the sewing machine needle just goes back and forth to form one stitch and stops above the fabric.

After that, if you release the pressure on the controller, move the work cloth by hand, and press the controller again, a new stitch will be formed and the main spindle 1 will stop in the same manner as described above. - Stitch formation, in other words, by repeating so-called needle stitching, it is possible to perform basting stitches having a stitch interval of arbitrary length.

Furthermore, when performing needle stitching, the helical spring 7 expands when the abutting portion 12a of the stop lever 12 abuts the engaging portion 8a of the sleeve 8, but the sleeve 8 prevents this abnormal expansion. thwarted.

Then, the stop lever 12 rotates and its abutting portion 12
When a is separated from the engaging portion 8a, the expanded helical spring 7 is immediately tightened, so that the sleeve 8 rotates slightly counterclockwise in FIG. 7.

Therefore, even if the stop lever 12 immediately rotates back, it will not engage with the engaging portion 8a of the sleeve 8 before the main shaft 1 starts, and the main shaft 1 will always make one revolution.

From the above explanation, it is clear how the basting stitch works,
If the intermediate lever 20 is not rotated as in this embodiment when it is moved downward by the operation of the electromagnetic solenoid 18, the movement locus of the tip of the claw portion 20a is a straight line of 1° as shown in FIG. Engagement portion 12b of the stop lever 12
Intersection point P with rotation locus 1□.

Unless the claw portion 20a of the intermediate lever 20 moves further downward, it will not be disengaged from the stop lever 12.

Therefore, the minimum required stroke of the plunger 18a at that time is S.

It is. In contrast, the plunger 1 in the above embodiment
The minimum required stroke of 8a is S, and the stop lever 12 can be moved and returned to its original position with an extremely small stroke.

Note that even if the manual operation switch 58 is opened or closed during the basting sewing, the short circuit for the diode 55 is not activated because the changeover switch 30 is switched to activate the solenoid operating circuit. The maximum rotational speed of the electric motor 36 is limited compared to that during AC operation, and the electric motor 36 rotates at a relatively low speed adjusted by the pressure applied by the controller 57.

As is clear from the above description, this embodiment is provided with a stop lever 12 whose one end 12a is always positioned by the action of a tension spring 15 on the rotation locus of the engaging portion 8a that rotates integrally with the main shaft of the sewing machine. , the stop lever is connected to the electromagnetic solenoid 18.
is rotated through engagement with the intermediate lever 20, the one end of the stop lever 12 is once moved out of the rotation locus of the engaging portion 8a, and then the intermediate lever 2 is immediately moved.
0, the stop lever 12 releases the engagement with the spring 15.
When the main shaft of the sewing machine rotates once, the main shaft is stopped to form one stitch, and the intermediate lever 20 is connected to the plunger 18a of the electromagnetic solenoid 18. Since the intermediate lever 20 is pivoted around the pivot point with the plunger 18a when the intermediate lever 20 is sucked together with the plunger 18a by the operation of the solenoid 18, the movement of the stop lever 12 is prevented. The subsequent return is ensured by a very slight stroke of the plunger 18a of the electromagnetic solenoid 18.

Therefore, the electromagnetic solenoid 18 can be one with a small stroke, in other words, one with a small capacity and a compact size, so that it can be easily incorporated into a narrow and limited space within the sewing machine frame.

Furthermore, during this basting period, the short circuit of the diode 54 is inactive due to the action of the changeover switch 30, so that no full AC voltage is applied to the sewing machine motor, and an unnecessary increase in the rotational speed is prevented.

When the changeover switch 30 is operated for a normal continuous edge, the solenoid activation circuit is disabled and the short circuit of the diode 54 is enabled,
The sewing machine motor 5 is activated by opening and closing the manual operation switch 58.
5 high-speed and low-speed two-speed control is possible.

Further, since the solenoid operating circuit is connected to the power terminal via the controller 57, the solenoid 1
8 is not required.

Therefore, the cord extending outward from the sewing machine includes a cord containing two wires for connection to an AC power source and a cord for connecting to controller 57, as in conventional sewing machines, as is apparent from FIG. All you need is a code that contains the lines of the book.

However, if a circuit were constructed as shown in FIG. 9 based on the conventional concept, its specific wiring diagram would be as shown in FIG. 10.

That is, the diode 54, the sewing machine motor 55 and the controller
If the solenoid operating circuit is connected in parallel with the motor drive circuit to which the roller 57 is connected in series, the interlocking switch 64 is closed in conjunction with the pressing operation of the controller 57.
is required within the solenoid actuation circuit.

Therefore, in the specific wiring, two extra wires will be extended from the sewing machine in order to arrange the interlock switch 64 inside the controller.

If these two wires and the two wires for connecting the controller are housed in one cord, the cord becomes thick and it becomes difficult to store the cord when the sewing machine is not in use.

As described in detail above, the present invention connects a motor drive circuit formed by connecting a sewing machine motor, a diode, and a controller in series between AC power supply terminals, and connects a motor drive circuit in parallel with the diode to short-circuit the diode. A short circuit including a manual operation switch is provided, and a solenoid operating circuit including an electromagnetic solenoid for controlling the drive of the sewing machine is provided in parallel to the series circuit of the diode and the sewing machine motor in the motor drive circuit, and the solenoid is actuated. By inserting and connecting a changeover switch in both circuits to selectively enable the short circuit and the short circuit, the short circuit is disabled when the solenoid is activated, and the manually operated switch is connected to the short circuit. Regardless of the opening/closing operation of the sewing machine motor, no full AC voltage is applied and it rotates at a relatively low speed, so the rotational speed does not increase unnecessarily, and its solenoid is activated by pressure from the control roller. In order to connect the controller to the sewing machine main body, there is no need for a separate switch means that is linked to the pressing operation of the controller, and an electric circuit can be constructed using the same wiring as in a conventional sewing machine. The code processing is not complicated, and its practical effect is extremely large.

[Brief explanation of the drawing]

The drawings show one embodiment embodying the present invention.
The figure is a front view of the main part with the cover and band wheel removed, Figure 2 is a sectional view taken along the line II-II in Figure 1, and Figure 3 is a partially cutaway view taken from the line III-III in Figure 1. 4 is an enlarged sectional view taken along the line IV-IV of FIG. 1, FIG. 5 is an electric circuit diagram, FIG. 6 is a front view equivalent to FIG. The figure is a partial enlarged view of Figure 6, Figure 8 is a wiring diagram of the circuit shown in Figure 5, and Figure 9 is a wiring diagram of the circuit shown in Figure 5.
The figure is an electrical circuit diagram different from that in Figure 5, and Figure 10 is its wiring diagram. In addition, 18 in the figure is an electromagnetic solenoid, 3o is a changeover switch,
52 and 53 are AC power terminals, 54 is a diode, 55 is a sewing machine motor, 57 is a controller including a variable resistor 56, and 58 is a manual operation switch.

Claims (1)

[Claims] 1 A motor drive circuit comprising a sewing machine motor, a diode, and a controller for supplying current to the sewing machine motor and controlling the speed of the motor, connected in series between AC power terminals, and a motor drive circuit for controlling the drive of the sewing machine. a solenoid operating circuit that includes an electromagnetic solenoid and is connected in parallel to the series circuit of the sewing machine motor and the diode in the motor drive circuit; and a solenoid operating circuit that includes a manually operated switch for shorting the diode and is connected in parallel with the diode. 1. A solenoid operation selection device for an electric sewing machine, comprising: a short circuit; and a changeover switch inserted and connected to the solenoid operation circuit and the short circuit for selectively activating the solenoid operation circuit and the short circuit.