JP6714963B2 - sewing machine - Google Patents

Description

The present invention relates to a sewing machine capable of controlling the pressing pressure of a cloth presser.

A conventional sewing machine includes a pressing rod that holds a cloth retainer, a pressing spring that applies downward pressing pressure to the cloth retainer via the pressing rod, and a lever that imparts an upward movement to the pressing rod against the pressing spring. The cloth pressing mechanism includes a solenoid that applies a lifting operation to the lever via a plurality of link bodies.
When lowering the cloth presser, the solenoid is not driven or the cloth pressure is performed by the spring pressure of the pressing spring with a minimum thrust, and when the cloth presser is raised, the solenoid is driven to perform the lifting operation. (For example, see Patent Document 1).

JP, 2011-092523, A

However, since the above-mentioned conventional sewing machine uses the solenoid as the drive source for raising the cloth presser, it is difficult to arbitrarily adjust the pressing pressure of the cloth presser by control.
Further, in recent years, since sewing is performed on objects to be sewn of various materials, there has been a demand for making it possible to adjust the pressing pressure of the cloth presser in a wider range.

An object of the present invention is to allow the pressing pressure of the cloth presser to be arbitrarily adjusted by control.

The invention according to claim 1 is a sewing machine,
A cloth retainer that presses the sewing object from above,
A pressing rod that holds the cloth presser at the lower end,
A pressing spring for urging the cloth pressing member via the pressing rod,
A presser height detection unit for detecting the height of the cloth presser,
A pressing motor that applies up-and-down motion of the cloth presser and that expands and contracts the pressing spring to apply a pressing pressure of the sewing object by the cloth presser,
An encoder that detects the output shaft angle of the pressing motor,
A control device that controls the pressing motor to adjust the amount of expansion and contraction of the pressing spring, and performs control to change and adjust the pressing pressure of the workpiece by the cloth pressing,
In a sewing machine equipped with
The pressing spring can be replaced with a plurality of types of pressing springs having different spring constants,
The control device controls the pressing motor so as to perform a descending operation from a state in which the cloth presser is separated above the needle plate ,
The output shaft angle of the presser motor at the time when the detected height of the cloth presser indicated by the presser height detecting unit is changed from the lowered state to the stopped state is stored as the origin position,
From the origin position, further drive the pressing motor by a predetermined amount,
When the encoder detects that the output shaft angle of the pressing motor has moved by the specified amount from the origin position, the pressing spring has a plurality of different spring constants based on the drive current of the pressing motor. It is characterized by having a spring type identification function for identifying which one of the pressing springs it is.

The invention according to claim 2 is
A cloth retainer that presses the sewing object from above,
A pressing rod that holds the cloth presser at the lower end,
A pressing spring for urging the cloth pressing member via the pressing rod,
A presser height detection unit for detecting the height of the cloth presser,
A pressing motor that applies up-and-down motion of the cloth presser and that expands and contracts the pressing spring to apply a pressing pressure of the sewing object by the cloth presser,
An encoder that detects the output shaft angle of the pressing motor,
A control device that controls the pressing motor to adjust the amount of expansion and contraction of the pressing spring, and performs control to change and adjust the pressing pressure of the workpiece by the cloth pressing,
In a sewing machine equipped with
The pressing spring can be replaced with a plurality of types of pressing springs having different spring constants,
The control device is
The presser motor is controlled so as to perform the descending operation from a state in which the cloth presser is separated above the needle plate ,
The detection height of the cloth presser indicated by the presser height detection unit, at the position where the stopped state from the lowered state, stores the output shaft angle of the presser motor as the origin position,
Further drive the pressing motor from the origin position with a predetermined drive current,
Based on the amount of change in the output shaft angle of the pressing motor detected by the encoder from the origin position at that time, a spring type for identifying whether the pressing spring is a plurality of types of pressing springs having different spring constants. It is characterized by having an identification function .

The invention according to claim 3 is the sewing machine according to claim 1 or 2,
The control device includes a table storage unit that stores table data indicating a relationship between an operation amount of the pressing motor and a pressing pressure generated in the cloth presser, which corresponds to each of a plurality of types of pressing springs having different spring constants. Have,
It is characterized in that control for setting the pressing pressure is performed based on table data corresponding to the pressing spring specified by the spring type identification function.

The invention according to claim 4 is the sewing machine according to claim 3,
Has a pressing pressure setting unit which performs input setting of the pressing pressure,
The pressing pressure setting unit has an input screen,
The control device changes the upper limit value/lower limit value of the settable spring pressure and the settable spring pressure resolution according to the pressing spring identified by the spring type identification function, and displays it on the input screen. It is a feature.

According to the present invention, the control device controls the pressing motor so as to perform the descending operation from the state in which the cloth presser is separated from the needle plate, and based on the reaction force received from the pressing spring in the process of descending the cloth presser. Since the pressing spring has a spring type identification function of determining which of a plurality of types of pressing springs having different spring constants, it is possible to specify the spring type of the exchangeable pressing spring.
As a result, it is possible to identify and use the spring type of the holding springs having a plurality of spring constants without mistake, and it becomes possible to set the holding pressure arbitrarily in a wide range of spring pressures, and more types of sewing materials can be sewn. It becomes possible to sew items.

It is a side view of a cloth pressing mechanism. It is a front view of a cloth pressing mechanism. It is a perspective view of a cloth pressing mechanism. It is an operation explanatory view in the state where the cloth presser of the cloth presser mechanism is set to the upper retracted position. It is operation|movement explanatory drawing of the state which lowered the cloth presser of the cloth presser mechanism to the needle plate. It is an operation explanatory view in the state where the cloth presser of the cloth presser mechanism is pressing the needle plate. It is a block diagram showing a control system of the sewing machine. 7 is a flowchart of a pressing spring identification process performed by the control device.

[Schematic Configuration of Embodiment]
Hereinafter, a sewing machine that is an embodiment of the present invention will be described in detail.
The sewing machine 100, which is an embodiment of the present invention, is a so-called lockstitch sewing machine, and is provided with various components such as a balance mechanism and thread tension that a general lockstitch sewing machine has. ..

The sewing machine frame 110 includes a sewing machine bed portion 101 located at a lower portion of the entire sewing machine, a standing body portion 102 provided upright at one longitudinal end of the sewing machine bed portion 101, and an upper end portion of the standing body portion 102. From the sewing machine bed portion 101 to the sewing machine arm portion 103 extending in the same direction (see FIG. 1).
The front end portion (end portion on the side of the surface portion) of the sewing machine bed portion 101 is the needle drop position, and the needle plate 11 is provided on the upper surface thereof.
In the following description, the horizontal direction parallel to the longitudinal direction of the sewing machine bed 101 is the Y-axis direction, the horizontal direction orthogonal to the Y-axis direction is the X-axis direction, and the X-axis and the Y-axis direction are orthogonal to each other. The direction of movement is the Z-axis direction.

[Needle up/down mechanism]
The needle up-and-down moving mechanism is arranged inside the sewing machine arm portion 103, is driven to rotate by the sewing machine motor 16 and is arranged along the Y-axis direction, and the needle bar that holds the sewing needle at the lower end portion. And a crank mechanism (not shown) that converts the rotational force of the upper shaft into a vertical reciprocating driving force and transmits the reciprocating driving force to the needle bar.

[Cloth holding mechanism]
FIG. 1 is a side view of the cloth pressing mechanism 70 in which a part of the sewing machine frame 110 is indicated by a chain double-dashed line so that the arrangement within the sewing machine frame 110 can be seen. Further, FIG. 2 is a front view of the cloth pressing mechanism 70 as seen from the surface side, and FIG. 3 is a perspective view showing a configuration of the cloth pressing mechanism 70 on the surface side.
As shown in these figures, the cloth presser mechanism 70 includes a cloth presser 71 for pressing the sewing object from above, a presser bar 72 for holding the cloth presser 71 at its lower end, and a presser which is a lifting drive source of the cloth presser 71. A motor 73, a transmission mechanism 74 for transmitting a lifting operation from the pressing motor 73 to the pressing rod 72 and the cloth presser 71, a pressing spring 75 for urging the cloth presser 71 via the pressing bar 72, and a height of the cloth presser 71 are set. The pressing height detecting unit 76 for detecting is provided.

The cloth presser 71 is a so-called boat-shaped presser whose bottom surface is smooth and whose upstream side (front side) in the cloth feeding direction is warped upward.
The presser bar 72 is arranged at two upper and lower positions inside the sewing machine arm 103 in a state along the Z-axis direction near the needle bar, and is supported by metal bearings 721 and 721 so as to be vertically movable.
Between the metal bearing 721 on the upper side and the metal bearing 721 on the lower side of the pressing rod 72, upper and lower rod holders 722 and 723 are fixedly mounted by hugging.

A sleeve 725 that is vertically slidable with respect to the pressing rod 72 is provided below the upper rod holder 722, and a coiled pressing spring 75 is provided between the sleeve 725 and the lower rod holder 723. It is equipped with the pressing rod 72 inserted.
The rod holders 722 and 723 and the cloth retainer 71 are fixedly mounted on the retainer rod 72 by fastening a set screw, and the retainer screw 72 is removed from the sewing machine frame 110 by loosening the set screw. Can be pulled upwards. Then, by this, the pressing spring 75 can be replaced.

On the other hand, as the pressing spring 75, a plurality of types having substantially the same inner diameter and different spring constants are prepared, and can be appropriately selected and replaced according to the pressing pressure required for various kinds of sewn products. it can.
It should be noted that the vertical distance between the side bar holder 722 and the lower bar holder 723 is set to be somewhat narrower than the total length of the pressing spring 75 and the sleeve 725, and between the side bar holder 722 and the lower bar holder 723. In the above, the pressing spring 75 and the sleeve 725 are mounted in a state in which there is no gap.

The sleeve 725 is a cylindrical body into which the pressing rod 72 can be inserted, and is vertically moved by the pressing motor 73 through the transmission mechanism 74 and positioned at an arbitrary height.
For example, when the sleeve 725 is lowered by the pressing motor 73, the lower pressing spring 75 is compressed, and the elastic force of the compressed pressing spring 75 is applied to the cloth pressing member 71 via the lower rod holder 723. At this time, by controlling the pressing motor 73 and arbitrarily positioning the height of the sleeve 725, the pressing spring 75 can be compressed to an arbitrary amount of compression and can be adjusted to an arbitrary pressing pressure.
When the sleeve 725 is raised by the pressing motor 73, the sleeve 725 contacts the upper rod holder 722, and the pressing rod 72 is raised via the upper rod holder 722, so that the cloth retainer 71 is lifted. It is possible to retreat to the release position of the sewn object which is separated above the.

Further, the presser bar 72 is set to have a length such that the upper end of the cloth presser 71 protrudes from the upper part of the sewing machine arm 103 even when the cloth presser 71 is lowered to the upper surface of the needle plate 11. Is equipped with a picking member 724 for picking up the cloth presser 71 by hand.
Since the cloth pressing mechanism 70 can move the cloth pressing member 71 up and down by the pressing motor 73, the cloth pressing mechanism 71 can be moved up and down by manually operating the link mechanism as in a conventional sewing machine. It does not have a lifting lever.
However, when the power supply to the sewing machine is cut off due to a power failure or the like, the cloth retainer 71 remains in a lowered state. Therefore, a handle member 724 is provided at the upper end portion of the presser bar 72 to provide the cloth retainer 71. Is configured so that it can be easily retracted upward.

The presser motor 73 is supported by a plate-shaped bracket 731 on the upper inner side of the vertical body 102 with its output shaft oriented in the X-axis direction.
The pressing motor 73 is a stepping motor and can be positioned at an arbitrary axis angle in units of a predetermined minute angle.
Although not shown in FIGS. 1 to 3, an encoder 732 is connected to the output shaft of the pressing motor 73 (see FIG. 7), the shaft angle of the output shaft is detected, and the controller 90 is detected. It has been entered.

The transmission mechanism 74 includes a main driving gear 741 fixedly mounted on the output shaft of the pressing motor 73, a substantially fan-shaped driven gear 742, and a bell crank-shaped link member 745 having bifurcated rotating arms 746 and 747. The driven gear 742 and the connecting rod 749 that connects the link member 745 are provided.

The main driving gear 741 is a spur gear and meshes with the driven gear 742.
The driven gear 742 is a fan-shaped gear supported rotatably around the X axis in the sewing machine frame 110, and teeth that mesh with the main driving gear 741 are formed only in an arc-shaped portion thereof. The teeth of the driven gear 742 have a larger effective diameter than that of the main driving gear 741, and the rotation input from the main driving gear 741 is greatly reduced and transmitted. Thereby, the resolution of the compression amount adjustment of the pressing spring 75 by the pressing motor 73 can be increased.
Further, the driven gear 742 includes an arm portion 743 extending in the rotation radius direction, and the arm portion 743 is connected to one end portion of the connecting rod 749 so as to be rotatable about the X axis. When the driven gear 742 receives the torque from the main driving gear 741 and rotates, the driven gear 742 imparts a movement operation substantially along the Y-axis direction to one end of the connecting rod 749.
The connecting rod 749 is disposed in the sewing machine arm 103 in a state substantially along the Y-axis direction, and the other end is connected to one rotating arm 746 of the link member 745 so as to be rotatable around the X-axis. ing.

In the link member 745, one rotating arm 746 is generally oriented in the Z-axis direction, and the other rotating arm 747 is generally oriented in the Y-axis direction, so that the link member 745 is rotatable about the X-axis in the sewing machine frame 110. It is supported. The other rotating arm 747 is connected to the sleeve 725 via a square piece 748. The square piece 748 is connected to the rotating arm 747 so as to be rotatable around the X axis, and is formed in a rectangular parallelepiped shape. The sleeve 725 supports the square piece 748 while sandwiching it from above and below, and allows the square piece 748 to move along the Y-axis direction.
As a result, when the link member 745 rotates, the rotating arm 747 rotates in the vertical direction, and the vertical movement operation is transmitted to the sleeve 725 via the square piece 748. Since the square piece 748 moves along the arcuate locus due to the rotation of the rotary arm 747, displacement also occurs in the Y-axis direction, but since the square piece 748 can move in the Y-axis direction with respect to the sleeve 725, the Z-axis piece can be moved. Only the moving movement in the direction is transmitted to the sleeve 725.

The height detection unit 76 mainly includes a detected body 761 supported by the lower rod holder 723, and a line sensor 762 that optically detects the height of the detected body 761.
Since the detected body 761 is supported by the lower rod holder 723, the detected body 761 moves up and down together with the cloth presser 71 and the presser bar 72.
The line sensor 762 is formed by arranging light-receiving elements along the Z-axis direction, and by being shielded by the detected body 761, the position (height) of the upper end of the detected body 761 in the Z-axis direction can be determined. Can be detected.

[Sewing machine control system]
The control system of the sewing machine 100 is shown in the block diagram of FIG. As shown in FIG. 7, the sewing machine 100 includes a control device 90 that controls the operation of each component. The sewing machine motor 16 and the presser motor 73 are connected to the control device 90 via respective motor drive circuits 16a and 73a.
Further, the sewing machine motor 16 and the pressing motor 73 are provided with encoders 161 and 732 for detecting the number of rotations thereof, and the encoders 161 and 732 are also connected to the control device 90 via the motor drive circuits 16a and 73a. There is.

The control device 90 includes a CPU 91, a ROM 92, a RAM 93, and an EEPROM 94 (EEPROM is a registered trademark), and executes various operation controls described later.
The ROM 92 stores programs for performing various controls described below.
Further, the EEPROM 94 stores table data indicating the relationship between the operation amount of the pressing motor 73 and the pressing pressure generated in the cloth presser 71, which individually corresponds to each of a plurality of types of pressing springs 75 having different spring constants. That is, the EEPROM 94 functions as a "table storage unit".
Further, an operation input section 96 for inputting settings such as a pressing pressure of the cloth presser 71 by the cloth presser mechanism 70 is connected to the control device 90 via an interface 96a. As a result, the operation input unit 96 functions as a “pressing pressure setting unit” that sets the pressing pressure.
Further, a pedal 95 for inputting a sewing speed according to a start of sewing and a stepping amount by a stepping operation is connected via an interface 95a.
The operation input unit 96 has an input screen 961 and displays information necessary for inputting various settings. For example, when the pressing pressure of the cloth presser 71 is set by the cloth pressing mechanism 70, the upper limit value/lower limit value of the setting of the pressing pressure and the numerical width (resolution) of the settable pressing pressure are displayed.
A line sensor 762 that detects the height of the cloth presser 71 is connected to the control device 90 via an interface 95a.

[Processing for identifying spring pressure of cloth pressing mechanism]
In the cloth pressing mechanism 70 of the sewing machine 100, as described above, the pressing spring 75 that determines the pressing pressure can be selected and replaced from a plurality of types of pressing springs 75 having different spring constants. Therefore, according to the program in the ROM 92, the control device 90 performs a process of identifying which of the plurality of types of pressing springs 75 having different spring constants is installed when the main power of the sewing machine 100 is turned on. To do.

Hereinafter, the pressing spring identification process will be described based on the operation explanatory diagram of the cloth pressing mechanism in FIGS. 4 to 6 and the flowchart in FIG. 8.
When the main power source of the sewing machine 100 is turned on, the control device 90 first drives the presser motor 73 in the direction in which the cloth presser 71 at the retracted position above the needle plate 11 is lowered (step S1: FIG. 4).

While lowering the cloth presser 71, the control device 90 monitors the height of the cloth presser 71 detected by the line sensor 762. Then, from the detection height of the cloth presser 71 indicated by the line sensor 762, it is determined whether the cloth presser 71 has descended to the upper surface of the needle plate 11 (step S3: FIG. 5). When the cloth presser 71 reaches the upper surface of the needle plate 11 by being lowered, the detection height of the cloth presser 71 indicated by the line sensor 762 is changed from the lowered state to the stopped state. This makes it possible to determine whether the cloth presser 71 has descended to the upper surface of the needle plate 11.

Accordingly, when it is determined that the cloth presser 71 has not reached the upper surface of the needle plate 11 (step S3: NO), the cloth presser 71 continues to descend (step S1), and the cloth presser 71 moves to the needle plate 11. When it is determined that the upper surface of the presser has reached the upper surface (step S3: YES), the output shaft angle of the pressing motor 73 indicated by the encoder 732 at the time of arrival is stored as the origin position, and a predetermined amount determined in advance from the origin position. Then, the output shaft of the pressing motor 73 is driven in the direction in which the cloth pressing member 712 descends (step S5: FIG. 6).

The control device 90 detects the drive current of the pressing motor 73 by the motor drive circuit 73a by the detection means (not shown), and detects the increase amount (torque) of the drive current from the origin position (step S7). When the output shaft of the presser motor 73 is driven from the origin position, the cloth presser 71 itself does not descend below the upper surface of the needle plate 11, but it is sandwiched between the descending sleeve 725 and the lower rod holder 723 in the stationary state. The pressing spring 75 is compressed. At that time, the drive current of the holding motor 73 required for driving the specified amount varies depending on the spring pressure of the attached holding spring 75. Therefore, when the encoder 732 detects that the output shaft angle of the presser motor 73 has moved from the origin position by the specified amount, the spring constant of the presser spring 75 can be calculated by obtaining the increase amount of the drive current of the presser motor 73. Can be specified. Therefore, the control device 90 can identify which of the plurality of types of pressing springs 75 currently mounted on the pressing rod 72 is different from the increasing amount of the drive current (the pressing springs 75 having different spring constants). Step S9 [spring type identification function]).

Further, the control device 90 selects the table data corresponding to the current pressing spring 75 from among a plurality of table data showing the relationship between the operation amount of the pressing motor 73 recorded in the EEPROM 94 and the pressing pressure generated in the cloth pressing 71. Is selected (step S11).
Further, the control device 90 displays the upper limit value/lower limit value of the pressing pressure and the numerical width (resolution) of the pressing pressure that can be set on the input screen 961 of the operation input unit 96 when the pressing pressure is set. The display corresponding to the pressing spring 75 is determined (step S13).
Then, the control device 90 ends the determination process of the pressing spring 75.

After the above process, when the setting input of the pressing pressure is performed from the operation input unit 96, on the input screen 961, the upper limit value/lower limit value of the pressing pressure set in step S13 and the settable pressing pressure are set. The display is changed to an input screen displaying a numerical width (resolution), and the input is restricted within a range that is greater than or equal to the lower limit value and less than or equal to the upper limit value that is displayed, and the numerical value input is accepted in units of the numerical width of the pressing pressure that can be set.
Further, when the pressing pressure of the cloth presser 71 is set, the control device 90 refers to the table data selected in step S11, drives the pressing motor 73 to the shaft angle that is the set pressing pressure, and the shaft concerned. Control to keep the angle.

[Effects of the embodiment]
As described above, the control device 90 of the sewing machine 100 controls the pressing motor 73 so as to perform the descending operation from the state where the cloth presser 71 is separated from the needle plate 11 above, and in the process of descending the cloth presser 71, It has a spring type identification function that determines which of the plurality of types of pressing springs 75 having different spring constants is used based on the reaction force received from the pressing spring 75. Can be specified.
As a result, the spring type of the pressing spring 71 having a plurality of spring constants can be discriminated and used without error, and the pressing pressure can be arbitrarily set with a wide range of spring pressures, so that more types of pressure can be applied. It becomes possible to sew a sewn product.

Further, the EEPROM 94 of the control device 90 stores table data showing the relationship between the operation amount of the pressing motor 73 and the pressing pressure generated in the cloth presser 71, which individually correspond to the pressing springs 75 of different types having different spring constants. Since the CPU 91 performs control to set the pressing pressure based on the table data corresponding to the pressing spring 75 specified by the spring type identification function, appropriate table data can be automatically obtained without setting and inputting the type of the pressing spring 75. It becomes possible to specify and adjust so as to obtain an appropriate pressing pressure.

In addition, the control device 90 can input by changing the upper limit value/lower limit value of the settable spring pressure and the numerical width (resolution) of the settable spring pressure according to the pressing spring 75 identified by the spring type identification function. Since the display of the input screen 961 of the operation input unit 96 is automatically changed so that it becomes possible to set an appropriate pressing pressure without setting and inputting the type of the pressing spring 75.

Further, in the above-described embodiment, in the process related to the spring pressure identification of the cloth pressing mechanism, the spring constant of the pressing spring 75 is calculated from the drive current of the pressing motor 73 required to drive the pressing motor 73 by a predetermined specified amount from the origin position. Was identified. Instead of this, as another embodiment, from the state where the cloth presser 71 reaches the upper surface of the needle plate 11 at the origin position, a predetermined drive current is applied to the presser motor 73, and the presser motor detected by the encoder 732 at that time. By determining the amount of change in the output shaft angle of 73 from the origin position, the spring constant of the pressing spring 75 is specified, and the attached pressing spring 75 is one of a plurality of types of pressing springs 75 having different spring constants. Alternatively, it may be identified.

11 needle plate 71 cloth retainer 72 retainer rod 75 retainer spring 73 retainer motor 90 controller 94 EEPROM (table storage unit)
96 Operation input section (pressing pressure setting section)

Claims (4)

A cloth retainer that presses the sewing object from above,
A pressing rod that holds the cloth presser at the lower end,
A pressing spring for urging the cloth pressing member via the pressing rod,
A presser height detection unit for detecting the height of the cloth presser,
A pressing motor that applies up-and-down motion of the cloth presser and that expands and contracts the pressing spring to apply a pressing pressure of the sewing object by the cloth presser,
An encoder that detects the output shaft angle of the pressing motor,
A control device that controls the pressing motor to adjust the amount of expansion and contraction of the pressing spring, and performs control to change and adjust the pressing pressure of the workpiece by the cloth pressing,
In a sewing machine equipped with
The pressing spring can be replaced with a plurality of types of pressing springs having different spring constants,
The control device is
The presser motor is controlled so as to perform the descending operation from a state in which the cloth presser is separated above the needle plate ,
The output shaft angle of the presser motor at the time when the detected height of the cloth presser indicated by the presser height detecting unit is changed from the lowered state to the stopped state is stored as the origin position,
From the origin position, further drive the pressing motor by a predetermined amount,
When the encoder detects that the output shaft angle of the pressing motor has moved by the specified amount from the origin position, the pressing spring has a plurality of different spring constants based on the drive current of the pressing motor. A sewing machine having a spring type identifying function for identifying whether the spring is a holding spring. A cloth retainer that presses the sewing object from above,
A pressing rod that holds the cloth presser at the lower end,
A pressing spring for urging the cloth pressing member via the pressing rod,
A presser height detection unit for detecting the height of the cloth presser,
A pressing motor that applies up-and-down motion of the cloth presser and that expands and contracts the pressing spring to apply a pressing pressure of the sewing object by the cloth presser,
An encoder that detects the output shaft angle of the pressing motor,
A control device that controls the pressing motor to adjust the amount of expansion and contraction of the pressing spring, and performs control to change and adjust the pressing pressure of the workpiece by the cloth pressing,
In a sewing machine equipped with
The pressing spring can be replaced with a plurality of pressing springs having different spring constants,
The control device is
The pressing motor is controlled so as to perform the descending operation from a state in which the cloth presser is separated from the needle plate above,
The detected height of the cloth presser indicated by the presser height detection unit, at the position where the stopped state from the lowered state, stores the output shaft angle of the presser motor as the origin position,
Further drive the pressing motor with a predetermined drive current from the origin position,
Based on the amount of change in the output shaft angle of the pressing motor detected by the encoder from the origin position at that time, a spring type for identifying which of the plurality of types of pressing springs the springs have different spring constants. A sewing machine having an identification function . The control device includes a table storage unit that stores table data indicating a relationship between an operation amount of the pressing motor and a pressing pressure generated in the cloth presser, which corresponds to each of a plurality of types of pressing springs having different spring constants. Have,
The sewing machine according to claim 1 or 2, wherein the control for setting the pressing pressure is performed based on table data corresponding to the pressing spring specified by the spring type identification function. Has a pressing pressure setting unit which performs input setting of the pressing pressure,
The pressing pressure setting unit has an input screen,
The control device changes the upper limit value/lower limit value of the settable spring pressure and the settable spring pressure resolution according to the pressing spring identified by the spring type identification function, and displays it on the input screen. The sewing machine according to claim 3, wherein the sewing machine is a sewing machine.

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