JP2002292175A - Sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sewing machine which is made easier than ever to adjust pitch ranges of seams in sewing. SOLUTION: A microcomputer 40 calculates the operation rate of a needlebar 12 to be changed based on a length L fed of a fabric (s21). The needlebar 12 reciprocates once each time a sewing machine motor 32 makes one turn synchronizing the rotation of the sewing machine motor 32 and hence, the rotational speed of the sewing machine motor 32 can be calculated as the operation rate of the needlebar 12. The rotational speed n of the sewing machine motor 32 is calculated by an expression as given by n=L/(A×T2) wherein L is a moving distance of the fabric, A is the pitch range of the seam and T2 is the execution interval of the second interrupt processing. Then, the microcomputer 40 changes the rotational speed of the swing machine 32 (s22). Subsequently, the microcomputer 40 initializes the variable L (set to zero) (s23).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewing machine capable of performing sewing while adjusting a feed amount of a cloth by hand.

[0002]

2. Description of the Related Art Conventionally, there is a sewing machine capable of performing sewing while manually adjusting an amount of cloth to be sent out, in which the operating speed of a sewing needle can be changed by operating a pedal.

According to the sewing machine constructed as described above, for example, when the cloth feeding amount is small, the operating speed of the sewing needle is reduced, and when the cloth feeding amount is large, the operating speed of the sewing needle is reduced. By increasing the speed, the pitch width of the stitch was made uniform.

[0004]

However, in such a sewing machine, it is necessary for the user to adjust both the amount of the cloth to be sent out and the speed of the sewing needle. Sewing could not be performed with uniform width.

[0005] It is an object of the present invention to provide a sewing machine in which even a non-skilled user can make the stitch pitch width uniform at the time of sewing.

[0006]

Means for Solving the Problems and Effects of the Invention In order to solve the above-mentioned problems, a sewing machine according to the present invention comprises a distance measuring means for measuring a distance at which a cloth is sent out at regular intervals, and a stitch pitch width. A pitch width setting unit to be set; and an operation of a sewing needle that forms a stitch corresponding to the pitch width based on the distance measured by the distance measurement unit and the pitch width set by the pitch width setting unit. A needle speed changing means for changing the speed.

The specific configuration of the distance measuring means of the sewing machine is not particularly limited as long as it can measure the distance over which the cloth has been fed. For example, the distance measuring means may be constituted by an image sensor and a microcomputer (hereinafter, referred to as a microcomputer). In this case, first
A still image of a certain range of cloth is captured by the image sensor at predetermined time intervals. Next, the microcomputer measures the deviation (displacement amount) of the two still images captured at predetermined time intervals as a distance. In addition, the microcomputer measures the distance that the cloth is sent out at regular intervals, but the shorter the time interval, the more frequently the operating speed of the sewing needle changes, and the pitch width must be precisely aligned. This is preferable because However, the value does not need to be extremely small as long as the pitch width can be made uniform with an error that causes no practical problem. This value may be determined in advance, or may be configured so that the user can set it arbitrarily.

Further, as the pitch width setting means, a switch capable of outputting a signal indicating a different pitch width by switching in multiple stages, an input button capable of inputting a numerical value and outputting a signal indicating the pitch width, and the like are used. can do. Further, the specific configuration of the needle speed changing unit is not particularly limited as long as the operating speed of the sewing needle can be changed according to the distance measured by the distance measuring unit.
For example, a motor, and a sewing needle operating mechanism that converts a rotational movement of the motor into a linear movement of a sewing needle, wherein the needle speed changing unit is configured to control the distance measured by the distance measuring unit and the pitch width The rotation speed of the motor may be controlled based on the pitch width set by the setting unit, so that the operating speed of the sewing needle that forms a stitch corresponding to the pitch width may be set. As the operating mechanism of the sewing needle, a mechanism that converts the rotational motion of the motor into a vertical reciprocating motion and moves the sewing needle in the vertical direction in accordance with the converted reciprocating motion can be used.

Further, the needle speed changing means should change the needle speed in accordance with a ratio L / A of the pitch width A set by the pitch width setting means and the distance L measured by the distance measuring means. The operating speed of the sewing needle may be determined. According to the sewing machine configured as described above, the operating state of the sewing needle is changed based on the distance measured by the distance measuring unit and the pitch width set by the pitch width setting unit. Operates slowly when the distance over which the cloth is delivered is short, and operates fast when the distance over which the cloth is delivered is long. Therefore, the operation speed of the sewing needle is changed so that the stitch is formed at the pitch width set by the pitch width setting means without the user adjusting the speed of the sewing needle according to the amount of the cloth sent out. In addition, the pitch width of the stitches can be made uniform at the time of sewing even if the user is not a skilled user.

[0010]

Next, an embodiment of the present invention will be described with reference to an example. The sewing machine 1 is capable of performing sewing while manually adjusting the feed amount of the cloth. As shown in FIG. 1, a bed 2 having a flat table portion, and one end of the bed 2 are provided. And an arm 4 extending in parallel from the upper end of the pillar 3 so as to face the bed 2.

The pillar 3 includes a start switch 20 for starting the sewing machine 1, a sewing switch 22 for starting sewing, and a pitch width selection switch 24 for setting a stitch pitch at the time of sewing. Have been. The arm unit 4 includes an image sensor 10 attached downward, a needle bar 12 for attaching a sewing needle 14, a presser foot 16 for holding a cloth at the time of sewing, and the like. Also, the arm 4
A needle bar driving mechanism (not shown) for moving the needle bar 12 in the vertical direction, a sewing machine motor 32 for transmitting power to the needle bar driving mechanism, a motor driving circuit 34 for controlling the sewing machine motor 32, and the like are built therein. ing. The motor drive circuit 34 controls the rotation speed of the sewing machine motor 32 by pulse control. The needle bar 12 is synchronized with the rotation speed of the
Is configured to perform one reciprocating up and down movement each time the rotating shaft rotates one time. When the needle bar 12 touches the cloth and then tries to remove the cloth again, the presser foot 16 presses the cloth so that the cloth together with the needle bar 12 does not move in the direction in which the needle bar 12 returns. When the needle bar 12 has been removed from the cloth, the presser foot 16 stops holding down the cloth and moves upward so that the cloth can be sent out freely.

Also, as shown in FIG.
A microcomputer (hereinafter referred to as a microcomputer) 40 is built in. The microcomputer 40 includes a CPU 44 that controls the entire sewing machine 1, a ROM 46 that stores various processes performed by the CPU 44, and an RA that stores variables necessary for the processes performed by the CPU 44 and results of the processes performed by the CPU 44.
M48; an input / output interface 42 for connecting the microcomputer 40 to various devices;
And a data bus 50 for transmitting data between the RAM 48 and the input / output interface 42. Of these, the RAM 48 stores a variable A corresponding to the set stitch pitch, a variable L corresponding to the cloth feeding amount, a still image captured from the image sensor 10, and the like.

[Processing Procedure Performed by Microcomputer 40] First, the processing procedure performed by the microcomputer 40 will be described with reference to FIG.
This process is started after the start switch 20 is switched to the ON side in a state where the cloth to be sewn is set on the sewing machine 1.

First, the microcomputer 40 operates the sewing switch 22.
Waits until is switched to the ON side (s1: N
O), when the sewing switch 22 is switched to the ON side (s1: YES), the pitch width is set to the variable A (s).
2). The pitch width can be set to an arbitrary pitch width from 2 mm to 10 mm in increments of 1 mm by switching the pitch width selection switch 24 that can be switched in multiple stages. In this process, the microcomputer 40 detects the pitch width set by the pitch width selection switch 24 and sets a variable A corresponding to the pitch width in the RAM 48.

Next, the microcomputer 40 controls the sewing machine motor 3
2 is started (s3). In this process, the microcomputer 4
0 outputs a control signal for instructing the motor drive circuit 34 to start the sewing machine motor 32. The motor drive circuit 34 to which the control signal has been input starts the rotation of the sewing machine motor 32 based on the control signal. The rotation of the sewing machine motor 32 causes the needle bar 12 to start reciprocating in the vertical direction via the needle bar driving mechanism.
Sewing can be performed while sending out the cloth. At this time, the sewing machine motor 32 is configured to start rotating at a predetermined rotation speed (in the present embodiment, once / second).

Next, the microcomputer 40 initializes a variable L in the RAM 48 (sets it to 0) (s4). The variable L is
This is used when measuring the distance over which the cloth has been sent out in a first interruption process described later. Next, the microcomputer 40 permits the execution of the first and second interrupt processes (s5). The first interrupt process is a process to be described later, and is a process that is repeatedly executed every predetermined time (0.01 second in the present embodiment) stored in the ROM 46 as the variable T1. The second interrupt process is a process to be described later, and is a process that is repeatedly executed every predetermined time (in the present embodiment, 0.5 seconds) stored in the ROM 46 as the variable T2. .

Next, the microcomputer 40 controls the sewing switch 22
Is turned off (s6: N
O), if the sewing switch 22 is switched off (s6: YES), the subsequent execution of the first and second interrupt processing is prohibited (s7). Then, the microcomputer 40 stops the sewing machine motor 32 (s8). In this process, the microcomputer 40 outputs a control signal for instructing the motor drive circuit 34 to stop the sewing machine motor 32.
The motor drive circuit 34 to which the control signal has been input stops the rotation of the sewing machine motor 32 based on the control signal. When the sewing machine motor 32 stops, the needle bar 12 that has reciprocated in the vertical direction through the needle bar drive mechanism
Also stops, and the sewing ends.

[First Interruption Process of Microcomputer 40] Next, a procedure of a first interruption process performed by the microcomputer 40 will be described with reference to FIG. First, the microcomputer 40 captures a still image of the cloth surface (s11). This still image is obtained by capturing, as a still image, a part of the image input to the microcomputer 40 as an image from the image sensor 10, and is stored in the image storage area of the RAM 48. In the image storage area, the latest still image captured in this process and the still image captured in the first interrupt process executed immediately before are stored.

Next, the microcomputer 40 checks whether or not the still image captured immediately before is stored (s12). At the first stage when the first interrupt processing is started, only the latest still image is stored in the image storage area. The distance that the cloth has been sent is measured based on the latest still image and the previous still image. Therefore, if the previous still image is not stored in the image storage area, the cloth is sent. The distance cannot be measured. Therefore, in this process, it is checked whether or not the distance to which the cloth has been sent can be measured by checking whether or not the still image captured immediately before is stored. As a result, the process waits until the first interrupt process repeatedly executed every 0.01 seconds is performed again.

If the still image taken immediately before in the process of s12 is stored (s12: YES), the microcomputer 40 measures the distance that the cloth has been fed (s13).
Since the first interrupt processing is configured to be repeatedly executed at a predetermined time period, the still image stored in the currently executing first interrupt processing stored in the image storage area and the immediately preceding still image are stored. There is a displacement (shift) of the image corresponding to the time difference of one cycle in the predetermined time cycle from the still image stored in the first interrupt processing. In this process, the distance over which the cloth is sent out, which corresponds to the displacement of the image, is measured as the image shift at each period of one cycle from the previous still image to the latest still image. The deviation of the image measured here is measured as the number of pixels constituting a still image, but the still image captured by the image sensor 10 is within a predetermined range (in the present embodiment, within a circle having a radius of 5 mm) on the cloth surface. Since the image is an image, a value indicating an area on the cloth surface (length and width) corresponding to the size of each pixel is obtained in advance. This value is stored in the ROM 46 in advance, and the microcomputer 40 converts the measured number of pixels into a value indicating the distance on the cloth based on the value in the ROM 46, and adds this value to the variable L in the RAM 48. Yes (s1
4). The value of the variable L is integrated as the distance that the cloth has been sent out before being initialized in a second interrupt process described later. Since the method of measuring the distance that the cloth is sent out is a known method, a detailed description is omitted.

[Second Interrupt Processing of Microcomputer 40] Next, the procedure of the second interrupt processing performed by the microcomputer 40 will be described with reference to FIG. First, the microcomputer 40 sets the variable L
Then, the operation speed of the needle bar 12 to be changed is calculated based on the above (s21). The variable L is the cloth moving distance integrated in the first interrupt processing. Further, the needle bar 12 is driven by the sewing machine motor 32 in synchronization with the rotation of the sewing machine motor 32.
When rotated, one reciprocation is performed in the vertical direction. Therefore, the rotation speed of the sewing machine motor 32 may be calculated as the operation speed of the needle bar 12. The rotation speed n of the sewing machine motor 32 is
A variable L indicating the moving distance of the cloth, a variable A indicating the pitch width of the stitch set in the processing of s2 in FIG. 3, and a variable T2 indicating the execution interval of the second interrupt processing, n =
It is calculated by a calculation formula represented by L / (A × T2). As a specific example, a variable L indicating the moving distance (mm) of the cloth is 1, a variable A indicating the pitch width (mm) is 2, and a variable T2 indicating a time interval (second) for capturing a still image is 0.5. Then, the rotation speed n of the sewing machine motor 32 becomes n = 1 / (2
× 0.5) = 1 (times / second).

Next, the microcomputer 40 is connected to the sewing machine motor 32.
Is changed (s22). In this process, the microcomputer 40 sets the rotation speed of the sewing machine motor 32 to s21.
A control signal for changing the rotation speed to the rotation speed calculated in the processing of (1) is output to the motor drive circuit 34. Then, the motor drive circuit 34 to which the control signal is input changes the rotation speed of the sewing machine motor 32 based on the control signal.

Then, the microcomputer 40 initializes the variable L (sets it to 0) (s23). By initializing the variable L in this process, the distance in which the cloth has been fed out before the next execution of the second interrupt process is added to the variable L every time the first interrupt process is performed. Become.

In the embodiment described above, the distance over which the cloth is sent out is determined by the image sensor 10 for inputting an image to the microcomputer 40 and the time corresponding to one cycle from the previous still image to the latest still image. The microcomputer 40 that measures an image shift functions as a distance measuring unit in the present invention.

The pitch width selection switch 24 functions as a pitch width setting means in the present invention. The microcomputer 40 that changes the operating speed of the needle bar 12 by changing the rotation speed of the sewing machine motor 32 that operates in synchronization with the needle bar 12 in the process of s15 in FIG. It functions as a means.

[Effect] According to the sewing machine 1 configured as described above, the microcomputer 40 measures the distance at which the cloth is fed out at regular time intervals, and according to the measured distance, the needle bar 12.
In order to change the operation speed, for example, when the distance over which the cloth is fed is short, the needle bar 12 operates slowly, and when the distance over which the cloth is fed is long, the needle bar 12 operates fast. Therefore, the operation speed of the needle bar 12 is changed so that the stitch is formed at the pitch width set by the pitch width selection switch 24 without the user adjusting the speed of the needle bar 12, so that the skilled The stitch pitch width can be made uniform at the time of sewing even if it is not a person.

[Modifications] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described specific embodiments, and may be implemented in various other forms. For example, in the above embodiment, the image sensor 10 is attached to the arm unit 4 in a downward direction, but the position where the image sensor 10 is attached is not particularly limited as long as the distance over which the cloth is fed can be measured. For example, it may be attached to the bed 2 upward.

Although the pitch width is set by the pitch width selection switch 24 which can be switched in multiple stages, the pitch width is set by way of example. However, the means for setting the pitch width is not particularly limited. May be configured so that the value directly input is set as the pitch width.

Also, an example in which the rotation speed of the sewing machine motor 32 is controlled by the motor drive circuit 34 has been described.
The software that functions equivalently to the software 4 described above may be incorporated, and the sewing machine motor 32 may be controlled by the software.

Further, although the configuration in which the distance over which the cloth is fed is calculated based on the still image extracted from the image sensor 10 has been exemplified, the method of calculating the distance at which the cloth is fed is not particularly limited. For example, a rotating member that rotates as the cloth moves on the upper part is
To calculate the distance over which the cloth is sent out based on the number of rotations and the length of the circumference of the rotating member.

A still image used for calculating the distance over which the cloth is sent is stored in advance in the RO of the microcomputer 40.
Although the example in which the variable T1 is captured at the time interval indicated by the value of the variable T1 stored in the M46 has been illustrated, the variable T1 may be configured to be stored in the RAM 48 so that the value can be changed. In addition, the smaller the value of the variable T1, the shorter the interval at which a still image is captured, and the more preferable it is that the distance over which the cloth is sent can be accurately measured. However, the value may not be an extremely small value as long as the value is such that the distance over which the cloth is fed can be calculated with a practically acceptable error.

The rotation speed of the sewing machine motor 32 is
The example in which the variable T2 is changed at a time interval indicated by the value of the variable T2 stored in the ROM 46 of the microcomputer 40 in advance has been illustrated. However, the variable T2 may be configured to be stored in the RAM 48 so that the value can be changed. Good. The smaller the value of the variable T2, the more frequently the operating speed of the sewing needle is changed, and the pitch width can be precisely adjusted, which is preferable. However, the value does not need to be extremely small as long as the pitch width can be made uniform with an error that causes no practical problem.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a sewing machine.

FIG. 2 is a block diagram showing a control system of a microcomputer in the sewing machine.

FIG. 3 is a flowchart of a processing procedure performed by a microcomputer in the sewing machine.

FIG. 4 is a flowchart of a first interrupt process performed by a microcomputer in the sewing machine.

FIG. 5 is a flowchart of a second interrupt process performed by the microcomputer in the sewing machine.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Sewing machine, 2 ... Bed part, 3 ... Pillar part,
4 ... arm part, 10 ... image sensor, 12.
..Needle bar, 14 ... sewing needle, 16 ... presser foot, 2
0 ... start switch, 22 ... sewing switch, 24
... Pitch width selection switch, 32 ... Sewing machine motor, 34 ... Motor drive circuit, 40 ... Microcomputer, 42 ... Input / output interface, 44 ... C
PU, 46 ... ROM, 48 ... RAM, 50 ...
-Data bus.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3B150 AA01 AA07 CB04 CE01 CE23 GE29 GF02 GF03 GF07 JA02 LA35 LA59 LA82 LB01 LB02 MA02 MA16 NA72 NB02 NC02 QA06 QA07

Claims (3)

[Claims] 1. A distance measuring means for measuring a distance at which a cloth is fed out at regular time intervals; a pitch width setting means for setting a pitch width of a stitch; a distance measured by the distance measuring means; Based on the pitch width set by the setting means,
A sewing speed changing means for setting an operating speed of a sewing needle forming a stitch corresponding to the pitch width. 2. A sewing machine comprising: a motor; and a sewing needle operating mechanism for converting a rotational movement of the motor into a linear movement of a sewing needle, wherein the needle speed changing means measures the distance measured by the distance measuring means; The rotational speed of the motor is controlled based on the pitch width set by the pitch width setting means, and the operating speed of a sewing needle forming a stitch corresponding to the pitch width is set. Item 7. The sewing machine according to Item 1. 3. The operating speed of a sewing needle to be changed according to a ratio of the pitch width set by the pitch width setting means to the distance measured by the distance measuring means. The sewing machine according to claim 1 or 2, wherein the following is determined.