JPH06142353A - Sewing machine - Google Patents

Abstract

PURPOSE:To prevent a thread entanglement from happening by prohibiting a fixative stitch from being newly assigned when a pattern with a fixative stitch is selected. CONSTITUTION:Memory devices 46, 48 store stitch data to form a pattern with a fixative stitch and stitch data to form a pattern without a fixative stitch for at least one pattern respectively, and at the same time, store stitch data to form a fixative stitch. A pattern selective switch 14 selects a desired pattern from the patterns which are stored in the memory devices 46, 48. A fixative- assigning switch 19 assigns a fixative stitch in order to form the fixative stitch on at least one of the front and rear ends of the selected pattern by combining the fixative stitch. Then, a CPU 42 controls the sewing machine in such a manner that the assignment of the fixative by the fixative stitch assigning switch 19 may be prohibited when a pattern with the fixative stitch is selected. By this method, a fixative stitch can be prevented from being formed on the top of the fixative stitch and a thread entanglement can be prevented from generating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewing machine, and more particularly to a sewing machine capable of forming a lock stitch.

[0002]

2. Description of the Related Art In a conventional sewing machine, tie-off stitching is performed at the start or the end of stitching in order to prevent stitch fraying, but there is a switch for executing tie-in stitching, while pressing the switch at the start or end of stitching. The backtack was sewn, and after the backtack was completed, the sewing machine was started again and the pattern was sewn.

However, there is a problem that the switch has to be kept pressed during the stop stitching, and during that time, both hands cannot be put on the work cloth, and the stitching occurs.

In order to solve this problem, there is known a sewing machine capable of designating a lock stitch. This sewing machine is provided with a tie stitching switch, and when the tie stitching is designated by operating the tie stitching switch after selecting the pattern, the tie stitch is automatically performed and then the pattern is formed.

[0005]

However, in the conventional sewing machine, when the pattern in which the stitch data of the stop stitch is already included in the stitch data of the pattern is selected,
When the tie stitching switch is operated, the tie stitch is formed by operating the tie stitching switch and the tie stitch is formed by the stitch data of the tie stitch in the stitch data of the pattern. There is a problem in that sewing is formed and thread clogging occurs. As the pattern in which the stitch data of the stop stitch is included in the stitch data of this pattern, there are a character pattern and a one-point pattern that are often formed independently.

The present invention has been made to solve the above-mentioned problems, and prevents the formation of a lock stitch on the lock stitch when a pattern including the lock stitch is selected. Providing a sewing machine that can

[0007]

In order to achieve this object, the sewing machine of the present invention, as shown in FIG. 1, has stitch data for forming a pattern with a lock stitch and a pattern without a lock stitch. At least 1 with stitch data for forming
Storage means for storing each pattern and also for storing stitch data for forming the lock stitch, and pattern selection means for selecting a desired pattern from the patterns stored in the storage means,
A backtack designating means for designating a backtack in order to form a backtack in combination with at least one of the front and back of the selected pattern, and a backtack designating means when a pattern containing the backtack is selected. And a control means for controlling so as to prohibit the designation of the lock stitch.

[0008]

In the sewing machine of the present invention having the above-mentioned structure, the storage means stores at least stitch data for forming a pattern with tack stitches and stitch data for forming a pattern without tack stitches. While memorizing each pattern,
The stitch data for forming the lock stitch is stored, and the control means, even when the lock stitch is designated by the lock stitch designating means when the pattern containing the lock stitch is selected by the pattern selecting means, the lock stitch Control is performed so as to prohibit the designation of the lock stitch by the designating means.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a front view showing the external structure of the sewing machine of this embodiment. The sewing machine frame 2 has a spindle (not shown).
Is rotatably supported, and a pulley 4 attached to the right end thereof and a sewing machine motor (not shown) arranged below the sewing machine frame 2 are connected by a belt. The main shaft is configured to rotate with the rotation of the sewing machine motor.

A needle bar 6 is supported on the head 2a of the sewing machine frame 2 so as to be vertically movable in synchronization with the rotation of the main shaft, and a needle 8 is attached to its lower end. Arm part 2
A needle bar swinging mechanism that swings the needle bar 6 in a direction orthogonal to the cloth feed direction is provided in b. Sewing machine frame 2
Inside the bed portion 2c, there are provided a feed dog up-and-down mechanism for moving the feed dog 10 up and down, and a feed dog front-back mechanism for moving the feed dog 10 back and forth. The feed dog up-and-down mechanism is driven by a sewing machine motor, the needle bar rocking mechanism is driven by a needle bar rocking step motor, and the feed dog front-back mechanism is driven by a feed tooth driving step motor.

The arm portion 2b is provided with a liquid crystal display 12 capable of displaying a sewing pattern and a pattern selection switch 14 corresponding to pattern selection means, and the head portion 2a is provided with a start / stop command for instructing start and stop of sewing. A stop switch 16, a lock stitch switch 18, and a lock stitch designating switch 19 corresponding to the tack stitch designating means are provided.

FIG. 3 is a block diagram showing the electrical construction of this embodiment. The pattern selection switch 14, the tie stitch switch 18, the start / stop switch 16 and the tie stitch designating switch 19 are of the automatic reset type. The control device 2 is configured to generate a low level signal when the switch is pressed and a high level signal when the switch is released.
0 input interface 22. Further, the needle position detection device 24 that generates a needle position signal corresponding to the upper position and the lower position of the needle is the input interface 2
Connected to 2. Further, the output interface 26 of the controller 20 is connected with a sewing machine motor 28, a feed dog driving step motor 30, drive circuits 34, 36, 38 of a needle bar swinging step motor 32, and a controller 40 of the liquid crystal display 12. There is.

The control unit 20 includes a CPU 42 and the CP.
It comprises an input interface 22, an output interface 26, which can be connected to the U42 via a bus 44, and a ROM 46 and a RAM 48 corresponding to a storage device.

The ROM 46 includes motors 28, 30, 32.
The motor drive control program for driving the sewing machine, the pattern selection control program, the pattern data creation control program, etc. are stored, and the stitch data for forming various patterns and the stitch data for forming the lock stitch are also stored. I remember. The RAM 48 is provided with various counters and flags necessary for pattern selection and pattern data creation control, and a memory for temporarily storing the calculation result of the CPU 42.

FIG. 4 shows the operation of this embodiment having the above configuration.
And it demonstrates with reference to the flowchart of FIG.

When the desired pattern is selected by operating the pattern selection switch 14, the CPU 42 stores the stitch data of the selected pattern in step S1 (hereinafter referred to as S1 and the same applies to other steps). RO
Set the read start address of M46. Then the CPU
42 resets the stitch number counter p and (S
2) Reset the tie stitch counter q (S3).

Next, the CPU 42 determines whether or not the selected pattern is a pattern such as a character pattern or a one-cycle pattern in which the stitch data of the backtack stitch is first included in the stitch data (S4). If the selected pattern does not include the lock stitch, it is determined as NO and the lock stitch designating switch is made effective (S5).

When the operator operates the lock stitching designation switch 19 and a low level signal is supplied to the CPU 42, the CPU 42 determines that the lock stitching is designated (S6), and the sewing is started. Is set (S7), the liquid crystal display 12 displays the indication of the lock stitching (S8), and the mode is switched to the lock stitch mode.

If the worker does not specify the stop stitch, the CPU 42 determines that the stop stitch is not specified (S
6) The display of the lock stitch designation on the liquid crystal display 12 is erased (S9), and the normal mode is set.

When a character pattern or a one-cycle pattern in which the backtack is included in the pattern is selected, it is determined that the backtack is in the pattern (S4), and the input of the backtack designating switch is invalidated. Then, it is displayed that the backtack is already in place (S10). Therefore, even if the operator operates the lock stitch designating switch 19, the lock stitch is not designated, and further lock stitches are prevented from being formed on the lock stitches.

Next, the pattern forming operation will be described.

First, the operator starts / stops the switch 1
When 6 is operated, the drive circuit 34 drives the sewing machine motor 28 to move the needle 8 up and down. Then, the needle position detecting device 2
4 to the needle position signal corresponding to the vertical position of the needle 8
2 is supplied to the ROM 4 in synchronization with the needle position signal in accordance with the data output program of FIG.
Read the stitch data from 6.

First, the CPU 42 determines whether or not the starting point flag f is set to 1 in step P1 (hereinafter referred to as P1 and the same applies to other steps). Here, the starting point flag f is set in the above-described pattern selection program according to the selected pattern and the presence or absence of the lock stitch designation. Further, f is 1 in S7.
Is set. And because f = 1,
The CPU 42 determines YES, sets the number of stitches for tack stitch according to the pattern in the tack stitch counter q (P
2) The start point flag f is reset to 0 (P3).

Here, the number of stitches for tie stitches according to the pattern is
For example, it is determined according to the type of the pattern, the sewing density of the pattern, the position of the stitch next to the lock stitch, and the like. That is, a pattern having a high stitch density has a large number of stitches for the stopper stitch, and a pattern having a low stitch density also has a small number of stitches for the stitch. If the position of the stitch next to the lock stitch is distant from the position of the lock stitch, increase the number of stitches of the lock stitch (temporary stitch pattern, etc.) so that the position of the stitch next to the lock stitch is the position of the lock stitch. If it is close to, reduce the number of stitches for tie stitches. Further, in the bleeding pattern, the number of stitches is increased when the bleeding stitch pattern for thick cloth is selected, and the number of stitches is reduced when the bleeding stitch pattern for thin cloth is selected. In this way, the number of stitches of the lock stitches is formed according to the selected pattern.

Next, the CPU 42 causes the lock stitch counter q
When the value of is not 0, it is judged to be NO (P4), the backtacking data is read out (P5), the value of the backtacking counter q is decremented by 1 (P6), and the read out data is output (P7).

In accordance with the stitch data obtained as described above, the drive circuits 38 and 36 are controlled so as to drive the needle swinging step motor 32 and the feed dog driving step motor 30, and stitches are formed.

At the timing of the next needle position signal, since the start point flag f is reset in the data output program, the CPU 42 judges NO (P
1), execute P4 without executing P2 and P3,
Thereafter, the above-described operations of P5 to P7 are repeated to form the number of setstitches at the beginning of sewing by the number set in the setstitches counter q.

When the value of the backtack stitching counter q becomes 0, the CPU 42 determines YES at the subsequent timing because the value of the backtacking counter q is 0.
4), ROM4 set by the above-mentioned pattern selection program
The stitch data is read from the read address of No. 6 based on the value of the stitch number counter p (P8). After that, the CPU 42
One is added to the value of the stitch number counter p (P9), and the read data is output (P7). Then, hereafter, the same steps are repeated to sequentially form the stitches of the pattern.

On the other hand, when the pattern without the backtack is selected and the backtack is not designated, the backtack counter q is reset to 0 and the start point flag f is set to 1 in the above-mentioned pattern selection program. Since it is not set, in the data output program, the process proceeds from step P1 to step P4 and step P8 to form the stitches of the pattern.

In the case of a pattern in which tie stitches are included in the pattern, the mode is not switched to the tie stitch mode, and in the data output program, similarly to the above, the process shifts from step P1 to step P4 and step P8. Form the seams of the pattern.

The stop stitch in the present embodiment is not limited to the type of stitches in which the stitches of a plurality of stitches are formed at the same position, and the stitches of a plurality of stitches are formed while performing a slight forward and backward feed. The present invention is also applied to a sewing machine that forms a stitch of a type that forms a multi-needle stitch by performing reverse feed (generally called a reverse stitch).

In the present embodiment, the number of stitches is changed according to the type of pattern. For example, a detector for detecting the cloth thickness is provided, and the number of stitches is increased when the cloth thickness is thick. The number of needles may be increased and the number of needles may be changed so as to reduce the number of needles when the cloth thickness is thin.

Further, in the present embodiment, the stop stitching is performed at the beginning of the sewing of the pattern, but the stop stitching may be performed at the end of the sewing of the pattern.

[0035]

As is apparent from the above description, the sewing machine of the present invention is designed to prohibit the new designation of the backtack stitch when the pattern including the backtack stitch is selected. It is possible to prevent the formation of a backtack on the sewing and prevent the occurrence of thread clogging.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of the present invention.

FIG. 2 is a front view showing the external configuration of the sewing machine according to the embodiment of the present invention.

FIG. 3 is a block diagram showing an electrical configuration of the sewing machine.

FIG. 4 is a flowchart showing an operation at the time of selecting a pattern in the sewing machine.

FIG. 5 is a flowchart showing an operation at the time of pattern formation in the sewing machine.

[Explanation of symbols]

 14 Pattern selection switch 19 Lock stitch sewing switch 20 Control device 42 CPU 46 ROM

Claims (1)

[Claims] 1. At least one stitch data for forming a stitched pattern and stitch data for forming a stitchless pattern are stored, and
Storage means for storing stitch data for forming tie stitches, pattern selection means for selecting a desired pattern from the patterns stored in the storage means, and at least one of before and after the selected pattern For the purpose of forming a lock stitch in combination with one side, lock stitch designating means for designating the lock stitch and for prohibiting designation of the lock stitch by the tack stitch designating means when the pattern containing the lock stitch is selected A sewing machine comprising: