JP2658611B2 - sewing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a presser foot device for a sewing machine which applies presser pressure to a work cloth placed on a sewing machine bed via a presser foot based on the urging force of a presser spring.

[0002]

2. Description of the Related Art Conventionally, for example, in order to sew along four sides of a square work cloth, the number of stitches required for sewing on each side is set in advance, and the number of stitches set at the time of forming a stitch is sewn. After performing the operation, the work clamp is lifted and the work clamp is raised to enable the worker to turn the work cloth.Then, when the worker operates the foot pedal, the work clamp is lowered to start sewing the set number of stitches in the next process. Sewing machines adapted to be used are known.

[0003]

However, in the above-described conventional apparatus, the sewing operation can be performed efficiently when each step is straight stitching. When curved stitches forming stitches are included, there is a problem that the sewing operation cannot be performed smoothly.

That is, since the cloth feed of the sewing machine is performed by sandwiching the work cloth between the feed dog which is moved in and out of the needle plate and fed in four motions and the cloth presser, the urging force of the presser spring is set strongly. In this case, the pinching pressure is increased to increase the feed efficiency of the feed dog. In order to carry out curve stitching in this state, when feeding the work cloth between the feed dog and the presser foot, it is necessary to manually forcibly shift the work cloth laterally along the shape of the work cloth. In some cases, it is not easy to send. This is because, when the work cloth is moved between the needle plate and the presser foot (when the feed dog is immersed from the needle plate), the lateral movement of the work cloth is performed against the holding pressure. This is particularly noticeable when the work cloth is thin.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a method of pressing a presser foot during sewing.
Pressure can be changed automatically,
An object of the present invention is to provide a presser foot device for a sewing machine that can easily perform curved sewing.

[0006]

According to the present invention, there is provided a sewing machine capable of changing a presser foot pressure according to the present invention. The presser bar has a presser foot at a lower end and is supported by a sewing machine frame so as to be able to move up and down. a pressing spring for urging downward toward the presser bar to the work cloth that is placed on the bed, about the progress of the sewing
And a memory storing change data of the biasing force of the presser spring.
Storage means and change data stored in the storage means.
Changing means for changing the biasing force of the presser spring
In particular, in the storage means,
When performing regeneration sewing based on the changed data
A play key for setting the play sewing mode and its play
Sewing starts in the regeneration sewing mode where the key is operated
From the storage means according to the progress of sewing after the sewing
Reading means for reading encrypted data, and the reading means
Pressure in the change data read out by
Pressure reduction signal discriminating means for determining whether there is a signal to be applied
And the change data read by the reading means.
To determine if there is a signal in the
Pressure recovery signal determination means to perform, the changing means,
It is composed of a servo solenoid and its servo solenoid
The pressure is reduced by the pressure reduction signal discriminating means.
When it is determined that there is a signal to be
, And the pressure restoration signal discriminating means is
It is determined that there is a signal for restoring the presser pressure.
And is configured to restore the biasing force of the presser spring.
I have.

[0007]

The change data of the biasing force of the presser spring is stored in advance in the storage means in relation to the progress of sewing. When sewing is actually started, the reading means reads the change data from the storage means according to the progress of sewing , and the servo solenoid as the changing means sends the pressure reduction signal.
Signal discriminating means has a signal to reduce the presser pressure
Is determined, the urging force of the presser spring is reduced,
Further, the pressure restoring signal determining means restores the presser pressure.
When it is determined that there is a signal to
Restore power. For this reason, for example, when performing linear sewing at a predetermined distance after performing linear sewing at a predetermined distance, and then performing linear sewing again at a predetermined distance, the presser foot in the case of curve sewing is less than the presser pressure of the linear presser foot. If the pressure is set low and the timing of changing the presser pressure is related to the progress of sewing from the start of sewing, the presser pressure will be changed automatically during sewing, greatly improving workability. It is.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in a playback sewing machine will be described in detail with reference to the drawings.

In the sewing machine according to this embodiment, as shown in FIG. 1, a presser bar 2 is supported on the head of a machine frame 1 so as to be vertically movable, and a presser bar clamp 3 is attached to an upper portion thereof. At the same time, a cloth presser 4 is attached to the lower end. A presser spring 5 as a spring member is disposed on the presser bar 2, and always presses the cloth presser 4 downward to apply a presser pressure to the work cloth. A first rotating lever 6 is rotatably supported in the sewing machine frame 1 in proximity to the presser bar holder 3, and is urged by a spring 7 to rotate in a direction to engage with the presser bar holder 3. ing. A second turning lever 8 is rotatably supported in the sewing machine frame 1 corresponding to the first turning lever 6, and is provided between one arm portion and the first turning lever 6. A connecting rod 9 is interposed, and an operating rod 10 is connected to the other arm.

As shown in FIG. 1 and FIG.
A substantially rod-shaped linking member 12 is supported by an oil pan 11 provided at a lower portion of the lower portion so as to be able to move up and down. Linkage unit 1
A pair of front and rear support legs 13 project from the lower surface of the oil pan 11 near the lower end of the oil pan 11, and a rotation shaft 14 is supported between the two support legs 13 so as to be rotatable around a horizontal axis. At the front end of the rotating shaft 14 is a front, substantially L-shaped operating rod 1.
5 is fixed via a mounting body 16, and an operating body 17 which can be pressed by a knee constituting an operating means is mounted on a lower left portion of the lower body.

An operating member 18 is fitted to the rear end of the rotating shaft 14 and is fixed by screws 19. Actuating member 1
A pair of protruding pieces 18a, 18b are formed on both right and left sides of the protruding member 8, and the linking member 12
Are engaged at the lower end. A spring 20 is fitted on the rotating shaft 14 at the front of the operating member 18, and both ends of the spring 20 are engaged with the operating member 18 and the oil pan 11, respectively. In the direction of rotation. A stopper screw 21 is adjustably screwed to the left projecting piece 18 b of the operating member 18, and is fixed at a predetermined adjustment position by a nut 22.

Then, as shown in FIG. 2, the tip of the stopper screw 21 always contacts the lower surface of the oil pan 11 based on the action of the spring 20, and the operating member 18 is held in the substantially horizontal original position. When the operating body 17 is pressed by the knee, the operating member 18 is rotated counterclockwise from the original position in FIG.
2, operating rod 10, second rotating lever 8, connecting rod 9, first
The cloth presser 4 is raised via the rotary lever 6, the presser bar clamp 3 and the like.

As shown in FIG. 1, a needle bar 23 is vertically movably supported on the head of the sewing machine frame 1 in front of the presser bar 2, and a needle 24 is attached to its lower end. When the main shaft (not shown) is rotated based on the drive of a motor 25 shown in FIG. 4 provided below the sewing machine frame 1, the needle 24 is moved up and down to move the needle 24 into the bed portion of the sewing machine frame 1. The seam is formed on the work cloth on the bed in cooperation with the provided thread catcher (not shown).

As shown in FIGS. 1 and 3, a rack 26 is supported in the head of the sewing machine frame 1 above the presser bar 2 so as to be movable left and right. A pinion 27 is rotatably supported in the head of the sewing machine frame 1 so as to mesh with the rack 26, and a screw hole 27a is formed at the center thereof. An adjusting screw 28 is screwed into the screw hole 27a of the pinion 27 so as to be able to move up and down, and is prevented from rotating by a key 29 engaged with a key groove 28a on one side thereof. The head of the pin 30 inserted through the presser spring 5 is
8 is in contact with the lower end.

A servo solenoid 31 is provided in the head of the machine frame 1 corresponding to the rack 26, and the tip of the armature 32 is fixed to the right end of the rack 26. The armature 3 of the servo solenoid 31
2 is moved out of the rack 26 and the pinion 2
7, the adjusting screw 28 is moved downward, and the pressing spring 5
Is compressed to apply a predetermined pressing pressure to the work cloth via the cloth presser 4, and the armature 3 of the servo solenoid 31 is pressed.
2, the adjusting screw 28 is moved upward through the rack 26 and the pinion 27, and the presser spring 5 is extended to reduce or release the pressing pressure of the presser 4 against the work cloth. ing.

A potentiometer 33 as a detector is disposed in the head of the sewing machine frame 1 corresponding to the rack 26, and a pinion 35 meshing with the rack 26 is fixed to the tip of an operating shaft 34. I have. When the pressure of the presser foot 4 against the work cloth is changed due to the projection or immersion operation of the armature 32 of the servo solenoid 31, the operating shaft 34 of the potentiometer 33 via the pinion 35 by the left and right movement of the rack 26. Is rotated, and a detection signal corresponding to the amount of movement of the armature 32 is output from the potentiometer 34.

As shown in FIG. 1, an operating pedal 36 having a front foot switch 71 and a rear foot switch 72 (see FIG. 4) is provided below the sewing machine frame 1 so as to be operated by a foot. The rear portion 36 of the operation pedal 36
When the a side is depressed and the front depress switch 71 is turned on, a start signal for rotating the motor 25 at a speed corresponding to the depressed amount is output, and after the depressing, the operation pedal 36 is set to the neutral state. When the front pedal switch 71 is turned off, the signal for stopping the rotation of the motor 25 and stopping the needle 24 at the bottom dead center below the needle plate is output.
When the rear depressing switch 72 is turned on by the rear depressing of the front part 36b side of No. 6, after the motor 25 is slightly rotated to perform thread trimming, the needle 24 is stopped at the upper dead center above the needle plate. Is output.

As shown in FIGS. 1 and 5, an operation box 37 is provided below the sewing machine frame 1. The operation box 37 is provided with a first presser pressure setting device 38 composed of a variable resistor or the like, and is applied to the work cloth via the presser 4 by the operation of projecting the armature 32 of the servo solenoid 31 during sewing operation. The pressing pressure of the pressing spring 5 can be set in advance according to the thickness of the work cloth and the like. The operation box 37 is provided with a second presser pressure setting device 39 composed of a variable resistor or the like. When performing curve sewing or the like while rotating the work cloth during sewing, the armature 32 of the servo solenoid 31 is immersed. By the operation, the reduced presser pressure when the presser pressure of the work clamp 4 against the work cloth is reduced can be set in advance according to the thickness of the work cloth or the like.

On the front face of the operation box 37, a key group 61 including a plurality of keys with lamps is provided. In the key group 61, the memory key 62 is used for trial sewing work.
Operated for setting the trial sewing mode and transferring all data. The memory key 63 is operated to store sewing data and the like at each sewing site of the work cloth during the trial sewing operation. The reproduction key 64 is operated for setting the reproduction sewing mode at the time of the reproduction sewing operation. The four pattern keys 65 are selectively operated to select different sewing patterns during the trial sewing operation and the reproduction sewing operation.

As shown in FIG. 1, a pair of front and rear support legs 40 project from the lower surface of the oil pan 11 in the vicinity of the left side of the operating body 17, and a rotating shaft 4 is provided between the two support legs 40.
1 is rotatably supported about a horizontal axis. An operating member 42 is fitted and fixed to a front end of the rotating shaft 41, and an operating projection 42a is formed on one side thereof. An operation lever 43 protrudes from a lower portion of the operation member 42, and the operation member 43 can be operated to the left by operating the operation lever 43 with a knee.

An operation switch 44 is provided below the sewing machine frame 1 corresponding to the operation protrusion 42a of the operation member 42. When performing the curve sewing or the like while rotating the work cloth in the middle of sewing, when the operating member 42 is turned to the left based on the operation of the operation lever 43, the operation switch 44 is closed and the operation switch 44 is closed. A command signal for operating the servo solenoid 31 is output from the operation switch 44.

Next, the configuration of a control circuit for mainly controlling the operation of the servo solenoid 31 in the sewing machine configured as described above will be described with reference to FIG. 4. A central processing unit (CPU) 51 has a read-only memory. (R
OM) 52 and random access memory (RAM) 53
Is connected.

The ROM 52 stores a program for controlling the entire sewing machine and the like, and the RAM 53 stores the operation amount of the potentiometer 33 corresponding to the movement amount of the armature 32 of the servo solenoid 31 and the holding pressure of the holding spring 5. The operation amount of the servo solenoid 31 is stored.

The CPU 51 has the key group 61,
Potentiometer 33, first presser pressure setting device 38, second
Presser pressure setting device 39, operation switch 44, needle position detector 70 provided at the end of the sewing machine spindle (not shown) for outputting a needle up signal and a needle down signal as the sewing machine spindle rotates, and a front depressing switch 71 for operation pedal 36. , A rear switch 72 is connected via the input interface 54, and various signals from them are input to the CPU 51. Further, the CPU 51 is provided with the servo solenoid 31 and the motor 25 by the output interface 55 and the driver 5.
6 and 57, and a drive or stop signal is output from the CPU 51 to the servo solenoid 31 and the motor 25.

The CPU 51 is provided with a stitch number counter 66 for counting the number of stitches based on one of the needle stitch signals from the stitch position detector 70 accompanying rotation of the main shaft of the sewing machine during the sewing operation. Further, the RAM of this embodiment
Reference numeral 53 denotes sewing data including the number of stitches and a feed pitch generated during sewing of each sewing portion of the work cloth during the trial sewing operation, and first and second presser pressure settings according to opening / closing of the operation switch 44 and the like. There is provided a storage area for storing pressure change data for giving, reducing or releasing the presser pressure of the cloth presser 4 based on the set values of the devices 38 and 39.

Next, the operation of the playback sewing machine configured as described above will be described.

In this sewing machine, when performing a trial sewing operation to sew a cloth piece W2 such as a pocket on the surface of the work cloth W1 as shown in FIG. 8, for example, the storage key 62 is turned on after the power is turned on. When a storage mode is set by operating and a pattern key 65 is selected and operated to specify one sewing pattern, a program shown in a flowchart of FIG. 6 described later is executed under the CPU 51.

First, in step S1, the CPU 51 outputs a command signal to the servo solenoid 31, causes the armature 32 to immerse, and presses the spring 5 against the work clamp 4.
Let the pressure release. Therefore, by pressing the operating body 17 with the knee in this state, the cloth presser 4 can be raised slightly, and the work cloth can be easily positioned at the start of sewing.

In the next step S2, the operation pedal 3
When the operation of No. 6 is awaited, the front pedal switch 71 is turned on by the front pedal operation on the rear portion 36a side of the operation pedal 36, and a start signal is input to the CPU 51. Then, the program proceeds to step S3. In step S3, a command signal is output to the servo solenoid 31, and the armature 32 is caused to protrude. The strong pressing pressure of the presser spring 5 set in advance by the first presser pressure setting device 38 is applied via the cloth presser 4. Applied to work cloth. In this state, in the next step S4, the motor 25 is started at a rotation speed corresponding to the front depression amount of the operation pedal 36, and the sewing operation of the sewing machine is started.

In the next step S5, it is determined whether or not the operation switch 44 has been turned on.
If N, the process proceeds to step S6, where a command signal is output to the servo solenoid 31 and the armature 32
, The pressing pressure of the pressing spring 5 against the work cloth is reduced to a weak pressure set in advance by the second pressing pressure setting device 39. Therefore, the sewing can be continued while rotating the work cloth in this state, and the curve sewing can be easily performed. In the next step S7, it waits for the operation switch 44 to be turned on again.
At the same time as n, the process proceeds to step S8 and the servo solenoid 3
The first armature 32 is protruded, and a strong pressing pressure of the pressing spring 5 is applied to the work cloth.

After the operation in step S8, or if the operation switch 44 is not turned on in step S5, the CPU 51 waits for the front depression switch 71 of the operation pedal 36 to be turned off in step S9, and the operation pedal 36 is turned off from the front depression state. When returned to the neutral state, the rotation of the motor 25 is stopped and the needle 24 is stopped at the bottom dead center,
Proceed to the next step S10. In this step S10, the needle 2 is detected by the needle down signal from the needle position detector 70.
When the needle down position of No. 4 is confirmed, the operation of the rear switch 72 is determined in the next step S11. And
If the front portion 36b side of the operation pedal 36 is not depressed rearward, the process returns to the step S1, the armature 32 of the servo solenoid 31 is immersed, and the pressing pressure of the pressing spring 5 on the work cloth is released. In the next step S2, the control waits for a front depression operation of the operation pedal 36. Therefore, the cloth presser 4 can be lifted lightly by the pressing operation of the operating body 17 in this presser pressure releasing state, and the cloth piece such as the work cloth and the emblem is rotated during the sewing, so that the cloth piece is attached to another edge of the cloth piece. Sewing along can be continued.

On the other hand, in the determination in step S11, when the rear depressing switch 72 is turned on based on the rear depressing operation of the front portion 36b of the operating pedal 36, the motor 25 is slightly rotated in the next step S12 and the thread is turned on. After the cutting is performed, the needle 24 is stopped at the top dead center. In the next step S13, when it is confirmed by the needle up signal from the needle position detector 70 that the needle 24 has stopped at the top dead center,
Proceeding to step S14, the armature 32 of the servo solenoid 31 is immersed, and the pressing spring 5
Is released. Therefore, in this state, the operating tool 1
The cloth presser 4 can be raised slightly by the pressing operation of 7, and the work cloth can be easily removed and the new work cloth positioned at the end of sewing.

In the next step S15, it is determined whether or not the operation pedal 36 has been depressed forward.
When 1 is turned on and the sewing operation is restarted, the process returns from step S15 to step S3, and the presser pressure is applied to the work cloth based on the operation of the servo solenoid 18,
If the operation pedal 36 is not depressed forward in step S15, it is confirmed that the operation of the sewing machine is completed.

In this manner, the sewing key 63 is sewn from the sewing start point P1 on the cloth piece W2 shown in FIG. 8 to the corner point P3 via the first curve point P2 and stopped under the needle. Is operated, the data is stored in the working area of the RAM 53 as a means for storing sewing data and presser pressure change data at the sewing site from the point P1 to the point P3. Thereafter, when the memory key 62 is operated in a state where the sewing is performed from the corner point P3 to the sewing end point P5 via the second curve point P4 and the needle is stopped, the sewing at the sewing site from the points P3 to P5 is performed. After the data and the change data of the presser pressure are stored in the working area of the RAM 53, all the data in the working area are transferred to the storage area corresponding to the designated sewing pattern, and the trial sewing operation ends.

Next, when performing the regenerating sewing operation following the trial sewing operation, the program shown in the flowchart of FIG. 7 is started under the control of the CPU 51 when the power of the sewing machine is turned on. The CPU 51 waits for the reproduction key 64 to be turned on in step S16, and the reproduction key 64 is turned on.
Then, the process proceeds to step S17 to wait for designation of a sewing pattern. When one sewing pattern is designated by the selection operation of the pattern key 65, the CPU 51 proceeds to step S18.
In step (3), storage data corresponding to the designated sewing pattern is read from the storage area of the RAM 53.

The following steps S19 to S22 correspond to the steps S19 to S22 in the flowchart shown in FIG.
A program similar to the operation from step 1 to step S4 is executed, and the presser foot is moved up and down by operating the operation body 17 in a state where the presser pressure is released by the operation of the servo solenoid 31, and the work cloth W1 and the cloth piece W2 are moved. Sewing start point P
1 is positioned at the needle drop point, and the servo solenoid 3
A strong presser pressure is applied by the operation of 1, and in this state, the sewing operation is started by starting the motor 25. In the next step S23, the number of stitches for each stitch is detected by the stitch number counter 66, the number of stitches is counted, and the program proceeds to the next step S24.

In this step S24, it is determined whether or not there is a command signal for reducing the presser pressure in the read data.
And the pressure of the presser is reduced by the operation of the servo solenoid 31. In the next step S26, waits for a command signal for holding the pressure recovered from in the read data, in step S 27 at the same time as the command signal, after the pressing pressure is restored in the applied state by the operation of the servo solenoid 31, the following Proceed to step S28. Therefore, FIG.
In the reproduction sewing work of the work cloth W1 and the cloth piece W2 shown in FIG.
The presser foot pressure is automatically reduced, and curve sewing can be easily performed. If there is no command signal in the determination in step S24, the program is executed in step S24.
From 25, the process bypasses step S27 and proceeds to step S28. The processing in step S24 is the same as that of the present invention.
As the pressure reduction signal determining means, the step S2
The processing step 6 is used as a pressure restoration signal discriminating means.
Steps S25 and S27 are used as changing means.
Each works.

In this step S28, it is determined whether or not the number of stitches of one sewing site counted by the stitch number counter 66 matches the number of stored stitches. When sewing is performed up to the corner point P3 on the cloth piece W2, the program proceeds to step S29, and the needle 24 is stopped at the bottom dead center. In this state, it is determined whether or not the pattern is completed in the next step S30. Is determined. If the needle is stopped at the corner point P3 as described above, it is in the middle of the pattern.
The program returns from step S30 to step S19, and the presser pressure is released by the operation of the servo solenoid 31. Therefore, in this state, the work cloth W1 and the cloth piece W2 can be rotated around the corner point P3 while the cloth presser 4 is raised by operating the operating body 17, and then the operation pedal 36 is turned on in step S20. By stepping forward on the rear portion 36a, the program proceeds to steps S21, S22,..., And performs sewing from the corner point P3 on the cloth piece W2 to the sewing end point P5 via the second curve point P4. Can be.

The sewing is performed as described above, and step S29 is performed.
When the end of the pattern is determined in step S30 after the needle down stop in step S30, the program proceeds to step S30.
Proceeding to 31, thread trimming is performed. Then, step S
At 32, the process waits for the needle 24 to stop at the top dead center. At the same time as the needle stops, the process proceeds to step S33, where the presser pressure is released by the operation of the servo solenoid 31, and the regeneration sewing operation ends.

The present invention is not limited to the configuration of the above-described embodiment. For example, as a configuration for raising and lowering the work clamp, a servo solenoid or the like may be used instead of the knee-operable operating body of the above-described embodiment. It is also possible to arbitrarily change the configuration of each part without departing from the spirit of the present invention, for example, by providing a device, and configuring the presser foot to move up and down with the driving of the driving device.

[0041]

As described in detail above, in the present invention, the change data of the biasing force of the presser spring is stored in advance in the storage means in relation to the progress of sewing, and the actual sewing is started. Reading means reads the change data from the storage means according to the progress of sewing , and
For the servo solenoid, the pressure reduction signal discriminating means
When it is determined that there is a signal to reduce the force,
The biasing force of the spring is reduced and the pressure restoration signal discriminating means
Determined that there was a signal to restore the presser pressure
When configured, the biasing force of the presser spring is restored.
ing. Therefore, for example, when performing straight stitching for a predetermined distance after performing straight stitching for a predetermined distance, and then performing straight stitching again for a predetermined distance, the presser pressure of the cloth presser in the case of straight stitching is smaller than that in the case of curve sewing. If the presser foot pressure is set to a low value and the timing of changing the presser foot pressure is related to the progress of sewing from the start of sewing, the presser foot pressure will be changed automatically during sewing. There is the advantage that it is greatly improved. As described above, since the presser pressure of the cloth presser can be automatically changed, it is possible to cope with various sewing modes such as a case where straight stitching and curved stitching are continuously performed, and has an advantage that it is practical. .

[Brief description of the drawings]

FIG. 1 is a partial perspective view showing an embodiment in which the present invention is embodied in a playback sewing machine and showing a mechanical configuration thereof.

FIG. 2 is an enlarged partial cross-sectional view showing a configuration for raising and lowering a presser foot.

FIG. 3 is a partial cross-sectional view showing, in an enlarged manner, a configuration for adjusting a presser pressure with respect to a cloth presser.

FIG. 4 is a control circuit diagram for controlling the operation of a servo solenoid and a motor.

FIG. 5 is a front view of the operation box.

FIG. 6 is a flowchart illustrating an operation of a CPU during a teaching operation.

FIG. 7 is a flowchart showing the operation of the CPU during the playback operation.

FIG. 8 is a partial plan view showing an example of sewing in which a cloth piece such as a pocket is sewn on a work cloth.

[Explanation of symbols]

 Reference Signs List 1 sewing machine frame 2 presser bar 4 work clamp 5 presser spring 17 operating body 31 servo solenoid 38 first presser pressure setting unit 39 second presser pressure setter 44 operation switch 51 CPU 62 storage key 63 memory key 64 playback key

Claims (1)

(57) [Claims] 1. A presser bar having a cloth presser at a lower end and supported by a sewing machine frame so as to be able to move up and down, and a presser spring for urging the presser bar downward toward a work cloth placed on a sewing machine bed. And the change in the biasing force of the presser spring in relation to the progress of sewing.
Memory means for storing data, said push based on a change data stored in the storage means
And a changing means for changing the biasing force of the fly spring in the sewing machine based on the change data stored in the storage means.
When performing stitching, the
In the raw stitching mode in which the raw key and the play key are operated,
Memory device according to the progress of sewing after the start of sewing.
Reading means for reading the change data from the stage, in a changing data read by the reading means
To determine whether there is a signal to reduce the presser pressure
Force reduction signal determining means and the change data read by the reading means.
To determine whether there is a signal to restore the presser pressure to
Power recovery signal determination means, the change means is configured by a servo solenoid,
In the servo solenoid, the pressure reduction signal discriminating means is provided.
When it is determined that there is a signal for reducing the presser pressure,
The pressure of the presser spring is reduced, and the pressure
There is a signal for the original signal discriminating means to restore the presser pressure.
A sewing machine capable of changing a pressing pressure , wherein when the determination is made, the urging force of the pressing spring is restored .