JP2003275487A - Sewing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the finish quality of sewing while preventing the occurrence of thread cast-off and shortening the end side needle thread residual quantity extending from a stitch hole at the start or resumption of sewing. <P>SOLUTION: When a sewing machine spindle is in a rotational phase of about 120°C and a sewing needle 7 is in the middle of descending while piercing cloth W in the first stitch at the start or resumption of sewing, an embroidery frame is moved in a +Y direction by the driving of a Y-direction feed motor, and the cloth W is fed by a prescribed micro quantity (about 0.5 mm) in the +Y direction. As a result, a sewing needle 7 descends in the state of small cloth resistance of a thread take-up side needle thread portion 29a to the cloth W and conversely in the state of large cloth resistance of an end side needle thread portion 29b to the cloth W. Consequently, thread cast-off can be positively prevented, and the needle thread residual quantity of the end side needle thread portion 29b can be made shorter than usual. <P>COPYRIGHT: (C)2003,JPO

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 which prevents thread loss when forming a stitch after the first stitch after sewing is started after thread cutting or thread change.

[0002]

2. Description of the Related Art Conventionally, an industrial embroidery sewing machine is provided with not only an embroidery device but also a flexible disk drive device, an operation panel having a liquid crystal display and a keyboard, so that sewing data of a plurality of types of embroidery patterns is stored in advance. The embroidery pattern can be easily sewn by mounting the flexible disk (FD) on the flexible disk drive device and selecting a desired embroidery pattern via the liquid crystal display.

By the way, when the sewing needle penetrates the work cloth and descends when forming the first stitch to sew the selected pattern, the cloth resistance of the work cloth on the balance side from the eye hole toward the balance is Since the end side upper thread portion extending from the eye of the sewing needle toward the upper thread free end is larger than the cloth resistance to the work cloth, the amount of the upper thread fed out from the balance to the eye hole as the sewing needle descends decreases. The deficiency may be compensated for by the end side upper thread portion through the eyelet hole, and the upper thread remaining amount of the end side upper thread portion may become short, resulting in thread omission. Therefore, in order to prevent the thread from slipping off, it is necessary to sufficiently secure the remaining amount of the upper thread on the end portion extending from the eyelet at the start of sewing, for example, about 6 to 7 cm.

Therefore, at the end of sewing or at the time of thread trimming at the time of thread change, the picker mechanism is operated to ensure a sufficient remaining amount of the upper thread on the end side, or at the start of new sewing, the operator makes an end The upper thread remaining amount on the section side is set sufficiently to prevent the first needle from coming off. In this case, after the stitch formation of the first stitch, the picker mechanism is actuated again so that the upper thread end that remains on the upper side of the work cloth is pulled under the work cloth, and the thread termination after sewing is omitted. It is possible to improve the quality of sewing.

[0005]

SUMMARY OF THE INVENTION In a conventional industrial embroidery sewing machine, the upper thread remaining amount of the end side upper thread portion is set to be about 1 mm so as to prevent thread loss of the first stitch when starting or restarting sewing. Since about 6 to 7 cm is secured, even if the end side upper thread portion is pulled under the work cloth by the picker mechanism, the long end side upper thread that has been pulled in is the next stitch. There is a problem in that the formation of the seams is adversely affected by being entangled with a plurality of seams and the hook after that.

Further, when the end side upper thread cannot be reliably pulled in to the lower side of the work cloth by the picker mechanism, extra thread terminating work after sewing is required. An object of the present invention is to shorten the remaining amount of the end side upper thread extending from the eyelet at the start of sewing or at the time of restarting sewing, and to prevent the occurrence of thread omission,
It is possible to improve the quality of sewing.

[0007]

Means for Solving the Problems A sewing machine according to claim 1 is
In a sewing machine in which a sewing machine including a needle bar having a sewing needle attached, a balance and a rotary hook is driven by a sewing machine motor, a cloth feeding mechanism capable of feeding and driving a work cloth by a driving force of a stepping motor and a sewing needle penetrated the work cloth. In this state, there is provided a feeding control means capable of controlling the cloth feeding mechanism so as to feed the cloth in a minute predetermined amount in the cloth feeding direction.

The sewing machine is driven by a sewing machine,
When the stitches are formed on the work cloth by the cooperation of the needle bar, the balance and the rotary hook, the feed control means feeds the cloth by the predetermined amount by the cloth feed mechanism via the stepping motor when the sewing needle penetrates the work cloth. The cloth feed is controlled in the direction. In this case, the fine predetermined amount of cloth feed control may be performed at the lowest position of the sewing needle, immediately before the encounter timing at which the blade point of the hook hooks the loop of the upper thread, or during the descending of the sewing needle. Good.

In particular, it is better to carry out a minute predetermined amount of cloth feeding while the sewing needle is descending, depending on the feeding direction, the work cloth is pressed against the end side upper thread extending from the eyelet of the sewing needle toward the upper thread free end. Since the cloth resistance of the end side upper thread portion against the work cloth increases, the thread dropout is less likely to occur. Therefore, the remaining amount of the end side upper thread that extends from the eyelet at the time of starting or restarting sewing can be shortened, and the end side upper thread part can be reliably pulled under the work cloth by the picker mechanism or the like. As a result, the thread finish after sewing can be omitted, and the quality of sewing is improved.

Here, in the case where the feed control means causes the cloth feed mechanism to carry out a minute predetermined amount of cloth feed while the sewing needle penetrates the work cloth and is descending (claim 2 dependent on claim 1). ), There is a possibility that the work cloth can be pressed against the end side upper thread portion while the sewing needle is descending, and the effect of preventing thread slipping can be exhibited.

Here, the feed control means feeds a small amount of cloth in a direction in which the work cloth is pressed through the needle thread free end or the needle thread portion continuing to the stitch side through the eye hole of the sewing needle. When the feeding mechanism is controlled (claim 3 dependent on claim 2), the work cloth can be reliably pressed against the end side upper thread portion while the sewing needle is descending, so that the end side upper thread portion is processed. The cloth resistance to the cloth can be increased, and the thread can be surely prevented from falling out.

Here, when the feed control means causes the cloth feed mechanism to carry out a minute predetermined amount of cloth feed when sewing one or more stitches after the start or restart of sewing (claims 1 to 3). According to claim 4) which depends on any one of the above, it is possible to prevent the thread from slipping off at the time of forming the first stitch immediately after the sewing is started or immediately after the sewing is resumed. Two
It is possible to prevent the thread from falling out when forming the stitches after the stitch.

Here, the sewing machine is an embroidery sewing machine,
When the feed control means causes the cloth feed mechanism to execute a cloth feed of a minute predetermined amount when sewing one or a plurality of stitches after thread cutting, color change of the upper thread, and thread breakage (claims 1 to 4). According to claim 5) dependent on any one of the above, when the embroidery pattern is sewn by the embroidery sewing machine, when thread cutting, color change of the upper thread, or thread breakage occurs, the first stitch formation immediately after the restart of sewing is performed. At the same time, it is possible to prevent the thread from falling out, and even if the thread is missing at the first stitch, the thread can be reliably prevented from being formed at the time of forming the stitches after the second stitch.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, the present invention is applied to a multi-needle type embroidery sewing machine. The multi-needle type embroidery sewing machine 1 will be described with reference to FIG.
A sewing machine arm 4 is arranged on a horizontal sewing machine table 3 placed on a base 2, and a support head portion 4a at a front end portion thereof is provided.
A needle bar support case 5 that supports five needle bars 6 so as to be movable up and down is mounted so as to be movable in the left-right direction. Sewing needles 7 are attached to the lower ends of the needle bars 6, respectively, and the spool 2
The upper thread 29 fed from 8 is supplied to the sewing needle 7 through the corresponding thread tensioner 8 and the balance 9.

The needle bar support case 5 is moved in the left-right direction by driving a needle bar changing motor 10 (see FIG. 2), and is moved to a driving position to select one of the needle bars 6 of the sewing machine motor 11. It is reciprocated up and down by driving. By the way, although illustration is omitted, a needle bar jump mechanism is housed inside the support head portion 4a, and this needle bar jump mechanism operates during thread changing or thread cutting, and the needle bar 6 is being driven.
Is forced to jump to its highest position. Therefore, the needle bar 6 is connected to the vertical drive unit of the needle bar jump mechanism at the second rotation of the sewing machine main shaft when starting or restarting sewing.

Here, the sewing needle 7 is formed with an eyelet 7a in the vicinity of the lower end thereof, and the needle thread 29 can be guided to the + Y direction side (front side) above the eyelet 7a by a predetermined distance. The thread groove 7b is formed. Therefore, the needle thread 29 supplied from the balance 9 is guided by the thread groove 7b and is guided by the eye hole 7a.
Is inserted. Here, the upper thread portion closer to the balance 9 than the eye hole 7a is referred to as a balance side upper thread portion 29a, and the upper thread portion extending from the eye hole 7a toward the upper thread free end is the end side upper thread portion 29b.
Called.

The sewing machine table 3 is provided with a sewing machine bed 12 extending forward. As shown in FIG. 7, the upper surface of the front end portion of the sewing machine bed 12 has a needle hole 13a.
A needle plate 13 having a needle thread 13 and immediately below the needle plate 13 is a thread cutting solenoid 14 at the time of thread cutting timing.
Is provided with a thread cutting mechanism (not shown) capable of simultaneously cutting the upper thread 29 and the lower thread. Further, inside the sewing machine bed 12, as shown in FIG. 7, a rotary hook 15 that forms embroidery stitches on the work cloth W in cooperation with the vertical movement of the sewing needle 7 is rotatable by driving the lower shaft 16. Provided,
A picker mechanism (not shown) driven by the picker solenoid 17 is provided.

Since the rotary hook 15 has the same structure as a general rotary hook, its detailed description will be omitted. Further, the picker mechanism uses the work cloth W for the end side upper thread portion 29b at the start of sewing.
Since the structure is the same as that of a general one for pulling to the lower side and for securing a sufficient upper thread remaining amount at the time of thread cutting, detailed description thereof will be omitted. In this case, the needle bar 6 having these sewing needles 7 attached to the lower end, the plurality of balances 9, the rotary hook 15 and the like are
The sewing mechanism is driven by the sewing machine motor 11 in synchronization with a sewing machine main shaft (not shown). The movement locus of the sewing needle 7 and the movement locus of the balance 9 in this case are shown in FIG.

However, the uppermost position of the sewing needle 7 is set to 0 of the sewing machine main shaft.
The rotation phase is °. In this way, the sewing needle 7 moves from 0 ° to 3
It reciprocates up and down over a rotation phase of 60 °,
When the phase is °, the tip of the sewing needle 7 is the needle hole 1 of the needle plate 13.
It is a timing to enter 3a, and a timing to encounter a sword tip (not shown) of the rotary hook 15 at a rotation phase of about 201 °. Therefore, in order to detect these various timings, an encoder disk (not shown) in which a large number of thin lines are radially printed is fixed to the main shaft of the sewing machine.

An encoder 18 for detecting individual thin lines printed on the encoder disk and generating a timing signal is mounted inside the sewing machine arm 4. The encoder signal (encoder pulse) from the encoder 18 is updated and stored in the pulse number memory of the RAM 55 of the control device 50 described later. However, the number of encoder pulses is reset every rotation of the sewing machine main shaft. Inside the base 2, 1
A pair of Y-direction moving arms (only one is shown) 20 are provided so as to be movable in the Y-direction (+ Y to -Y directions) within the XY plane by a Y-direction feed motor 21 (see FIG. 2).

The upper end of the Y-direction moving arm 20 projects upward so as to face the upper surfaces of the left and right ends of the sewing machine table 3. A support member 22 extending in the left-right direction is fixed between the upper ends of the pair of Y-direction moving arms 20, and an X-direction moving arm 23 is attached to the support member 22 by an X-direction feed motor 24 (see FIG. 2) in the XY plane. X direction (+ X ~-
It is provided so as to be movable in the X direction). Further, an embroidery frame 25 for detachably mounting the work cloth W is attached to the front end of the X-direction moving arm 23. In this case, 1
The pair of Y-direction moving arm 20, support member 22, X-direction moving arm 23, and the like constitute a cloth feeding mechanism.

Therefore, the work cloth W mounted on the embroidery frame 25 is moved in the + Y direction or the -Y direction by the Y-direction moving arm 20 driven by the Y-direction feeding motor 21 and at the same time, the X-direction feeding motor. Various embroidery characters such as characters and symbols are formed on the work cloth W by being moved in the + X direction or the −X direction by the X-direction moving arm 23 driven by 24. Here, these both feed motors 21 and 24 are
Each consists of a stepping motor. Five thread winding rods 27 are erected on a support plate 26 mounted and fixed on the upper side of the sewing machine arm 4, and thread windings 28 of a thread color required for embroidery sewing are mounted on each thread winding rod 27.

Here, the upper thread 2 fed from the spool 28
9 is guided by a guide member 30. Further, a flexible disk drive device 31 is built in the base 2, and an operation panel 32 is provided on the sewing machine table 3.
It is attached so that it faces the upper side of. On the operation panel 32, a liquid crystal display 33 capable of displaying characters and images in color, an embroidery character and stitch density applied to the work cloth W, and various functions for inputting the character height of the input character, a typeface and the like. In addition to the keys, a keyboard 34 having various function keys necessary for starting sewing and displaying a character string pattern to be sewn is provided.

Next, the control system of the multi-needle type embroidery sewing machine 1 is constructed as shown in the block diagram of FIG. The input / output interface 51 of the control device 50 includes a display controller (LCDC) 41 for a color liquid crystal display (LCD) 33, a keyboard 34, a plurality of drive circuits 42 to 47, and a flexible disk drive device (FDD). A flexible disk controller (FDC) 48 for 31 is electrically connected to each.

The drive circuit 42 is for driving the sewing machine motor 11, the drive circuit 43 is for driving the thread cutting solenoid 14, the drive circuit 44 is for driving the X-direction feed motor 24, and the drive circuit 45 is for Y. The drive circuit 46 is for driving the direction feed motor 21, the drive circuit 46 is for driving the needle bar changing motor 10, and the drive circuit 47 is for driving the picker solenoid 17. On a flexible disk (magnetic recording medium) FD detachably mounted on the flexible disk drive device 31, plural kinds of sewing data such as alphabetic characters, kanji, and symbols are recorded in association with embroidery pattern numbers. There is.

The controller 50 has an input / output interface 51, a CPU 53 connected to the input / output interface 51 via a bus 52 such as a data bus, and an R.
It is composed of an OM 54, a RAM 55, and the like. ROM
Reference numeral 54 stores a drive control program for driving the respective motors 10, 11, 21, 24, a sewing control program at the start of sewing, which is unique to the present application, a general cloth feed control program, and a lock stitch control program. ing. RAM
55 is provided with not only a sewing data memory for storing sewing data for embroidery sewing, but also various memories such as a buffer, a counter, and a pointer for temporarily storing the calculation result calculated by the CPU 53.

Next, at the start of new sewing, after the color change of the upper thread 29, after thread cutting, and further after thread cutting, the sewing control at the time of disclosing the sewing is executed by the control device 50 of the embroidery sewing machine 1. The routine will be described with reference to the flowchart of FIG. In the figure, reference numeral Si (i = 11, 12, 1
3, ...) are each step. However, as a preparation for the start of this control, the number of times a small predetermined amount of cloth is fed when the sewing needle 7 descends after penetrating the work cloth W is input and set by the keyboard 34 of the operation panel 32 at the start or restart of sewing. , And is stored in advance in the minute feed number memory of the RAM 55.

This control is started when a sewing start command is received at the start of new sewing, or when a thread resuming command is issued after the thread is cut or the thread is cut due to color change or the end of sewing. First, a minute predetermined amount of cloth feed execution number A is read from the minute feed number memory and is set as a counter value I (S11), and the sewing machine spindle is rotationally driven at a sewing start speed of about 100 rpm (rotation number / minute). (S12). Next, the number of encoder pulses in the pulse number memory is read (S13).

At this time, at the second rotation of the main shaft of the sewing machine, the needle bar 6
Is connected to the up-and-down drive part of the needle bar jump mechanism, so when the main shaft of the sewing machine makes a rotation phase of about 120 ° after two rotations, that is, as shown in FIGS.
When it is in the middle of descending after passing through (S14: Yes), the embroidery frame 25 is moved in the + Y direction by the drive of the Y-direction feed motor 21, and the work cloth W is clothed in the + Y direction by a small predetermined amount of about 0.5 mm. It is sent (S15). Then, in this pressed state, the lowering operation of the sewing needle 7 continues.

As a result, as shown in FIG. 7, while the sewing needle 7 is descending after penetrating the work cloth W, the work cloth W is pressed against the end side upper thread portion 29b which is continuous with the free end by passing through the eye hole 7a. The caused condition occurs. Further, since the work cloth W is fed by a minute predetermined amount in the + Y direction, a slight gap d is formed on the + Y direction side of the sewing needle 7, and the balance is guided to the gap d side by the thread groove 7b. Since the side upper thread portion 29a is provided,
The pressing of the work cloth W on the balance-side upper thread portion 29a is released. While maintaining this state, the sewing needle 7 descends to a rotation phase of about 180 ° (the lowest position of the sewing needle 7) shown in FIG.

That is, the cloth resistance of the balance-side upper thread portion 29a with respect to the work cloth W becomes smaller, and conversely, the end side upper thread portion 29a.
Since the sewing needle 7 descends in a state in which the cloth resistance of the work cloth W of b becomes large, there is almost no possibility that the upper thread remaining amount of the end side upper thread part 29b will be small, and the upper thread remaining amount will be sure. Reserved. In this case, when the difference between the cloth resistance of the balance-side upper thread portion 29a and the cloth resistance of the end-side upper thread portion 29b is large, the balance-side upper thread portion 29a having the smaller cloth resistance rather passes through the eyelet 7a. Move to the free end side, and the end side upper thread portion 2
The remaining amount of the upper thread of 9b may increase.

Therefore, by pressing the work cloth W against the end side upper thread portion 29b while the sewing needle 7 descends while penetrating the work cloth W, the cloth resistance of the end side upper thread portion 29b is reduced. It becomes large, and it is possible to reliably prevent the yarn from coming off. Therefore, the upper thread remaining amount of the end side upper thread portion 29b at the start of sewing can be made shorter than usual (for example, about 4 to 5 cm). After that, the encoder pulse number of the pulse number memory is read (S16), and when the rotational phase reaches about 200 °, that is, when the lowering operation of the sewing needle 7 is completed (S17: Yes), the picker mechanism is operated. (S18).

As a result, the needle thread loop formed by being hooked on the sword tip of the rotary hook 15 is locked by the locking portion of the picker mechanism, and the needle thread remaining amount of the end side needle thread portion 29b is short. The part-side upper thread portion 29b can be reliably pulled in to the lower side of the work cloth W, the thread finishing after sewing can be omitted, and the sewing quality can be improved. Next, the sewing data for one stitch is read (S19), and the Y-direction feed amount is calculated so as to be reduced by about 0.5 mm executed in S15 (S20). Then, the cloth feed processing control (see FIG. 5)
Is executed (S21).

When this control is started, first, the number of drive pulses for executing the X-direction feed amount by the X-direction feed motor 24 is calculated based on the sewing data for one stitch, and at the same time,
The drive pulse number for executing the Y-direction feed amount by the Y-direction feed motor 21 is calculated (S31), and when the next feed timing comes (S32, S33: Yes), it is synchronized with the encoder signal from the encoder 18. , When the drive pulse is output to both feed motors 21 and 24 (S34, 35: No) and all drive pulses are output (S35), this control is ended and the process returns to S22 of the sewing control at the start of sewing. .

Next, in the sewing control at the start of sewing, the operation of the picker mechanism is stopped (S22), the counter value I is decremented by 1 (S23), and if the counter value I is "0" (S24: Yes), and the lock stitch process control (see FIG. 6) is executed (S25), and this control is ended and the process returns to the main routine. However, the counter value I is "0"
If not (S24: No), S13 to S23 are repeatedly executed until the counter value I becomes "0". That is, when a plurality of stitches are sewn at the time of starting or resuming sewing, a minute predetermined amount of cloth feed is executed each time, and even if thread loss occurs at the first stitch, stitch formation at the second and subsequent stitches is formed. At this time, it is possible to reliably prevent the yarn from falling out.

When the lock stitch control is started, first, the sewing data for one stitch is read (S41). If the read data is feed data and not thread trimming data (S42: No) The sewing speed is calculated from the feed amount based on the feed data, and the rotation speed of the sewing machine spindle, that is, the rotation speed of the sewing machine motor 11 is calculated so that the sewing speed can be obtained (S43). Then, after the next feeding timing (S44, S45: Yes), the feeding process control is executed (S46), the thread breakage detection is executed (S47), the thread breakage is not detected, and the thread trimming flag is set. If not (S48: No), S41 to S48 are repeatedly executed and embroidery sewing is executed.

However, if thread breakage is detected and the thread trimming flag is set (S48: Yes), thread breakage warning processing is performed and sewing control is stopped. Then (S49), this control is terminated and the process returns to the main routine. By the way, when the embroidery sewing is completed and the read data is the thread trimming data (S42: Yes),
The thread trimming mechanism is operated to execute the thread trimming process (S5
0). Here, in particular, S13 to S15 of the sewing control at the start of sewing shown in FIG. 4, the cloth feed control of FIG. 5, the control device 50 and the like constitute a feed control means.

Next, a modification of the above embodiment will be described. 1] If thread dropout easily occurs at the time of forming the upper thread loop, the Y-direction feed motor 21 is driven to feed a small predetermined amount (about 0.5 mm) of the work cloth W and the upper thread portion on the end side. 29
The time when the work cloth W is pressed against b may be just before the lowest position of the sewing needle 7 or just before the sword tip of the rotary hook 15 hooks the needle thread loop. 2) The time when the work cloth W is pressed against the end side upper thread portion 29b is not limited to one time, but may be 0.2 mm at a plurality of times at any plurality of points during the lowering of the sewing needle 7. The minute feed may be executed.

3] The minute predetermined amount of work cloth W is fed by approximately
The value is not limited to 0.5 mm, but may be set to an arbitrary value according to the type and thickness of the work cloth W and the type and thickness of the upper thread 29. 4] The cloth feeding direction by the minute predetermined feed amount for pressing the work cloth W to the end side upper thread portion 29b is not limited to the + Y direction, and the work cloth W can be pressed to the end side upper thread portion 29b. Any direction may be used as long as it is the direction.

5) The present invention should not be construed as being limited to the above-described embodiments and modified forms, and various modifications are added within a range not departing from the gist of the present invention, and practical patterns are shown. The present invention can be applied to various sewing machines such as a lockstitch sewing machine that is sewn exclusively.

[0041]

According to the invention of claim 1, the sewing machine driven by the sewing machine motor is provided, and the cloth feeding mechanism and the sewing needle penetrates the work cloth to feed the cloth in the cloth feeding direction by a minute predetermined amount. Since the feed control means capable of controlling the cloth feed mechanism is provided as described above, especially when a minute predetermined amount of cloth feed is executed during the lowering of the sewing needle, the needle thread is fed from the eyelet hole of the sewing needle depending on the feeding direction. There is a possibility that the work cloth can be pressed against the end side upper thread portion extending toward the free end, and the cloth resistance of the end side upper thread portion with respect to the work cloth is increased, so that the yarn dropout is less likely to occur.

Therefore, the end side upper thread remaining amount extending from the eyelet at the time of starting or restarting sewing can be shortened, and the end side upper thread portion can be securely placed on the lower side of the work cloth by the picker mechanism or the like. It is possible to pull in the thread, and it is possible to omit the thread termination after sewing, and it is possible to improve the quality of sewing.

According to the invention of claim 2, the same effect as that of claim 1 is obtained, but the feed control means feeds a minute predetermined amount of cloth while the sewing needle penetrates the work cloth and is descending. Since it is executed by the cloth feed mechanism, there is a possibility that the work cloth can be pressed against the end side upper thread portion while the sewing needle is descending, and the effect of preventing thread slippage can be exhibited.

According to the invention of claim 3, the same effect as that of claim 2 is obtained, but the feed control means is provided at the needle thread free end or the needle thread portion connected to the stitch side through the eyelet hole of the sewing needle. Since the cloth feed mechanism is controlled to feed a small amount of cloth in the direction in which the work cloth is pressed, the work cloth can be reliably pressed against the upper thread portion on the end side while the sewing needle is descending. The cloth resistance of the thread portion with respect to the work cloth can be increased, and the thread drop can be reliably prevented.

According to the invention of claim 4, the same effect as in any one of claims 1 to 3 is obtained, but the feed control means is
When one or more needles are sewn after the start or restart of sewing, the cloth feed mechanism is made to execute a minute predetermined amount of cloth feed, so the thread at the time of forming the first stitch immediately after the start of sewing or immediately after the restart. It is possible to prevent the thread from coming off, and even if the thread comes off at the first stitch, the thread can be prevented from being formed at the time of forming the stitches at the second and subsequent stitches.

According to the invention of claim 5, the same effect as in any one of claims 1 to 4 is obtained, but the sewing machine is an embroidery sewing machine, and the feed control means is thread cutting, color change of the upper thread, thread When sewing one or more stitches after breakage, the cloth feed mechanism is caused to execute a minute predetermined amount of cloth feed, so when sewing an embroidery pattern with an embroidery sewing machine, thread cutting, color change of the upper thread, thread When a breakage occurs, it is possible to prevent the thread from slipping off when the first stitch is formed immediately after the restart of sewing, and even if the thread is slipped off at the first stitch, the thread is lost when the stitches are formed on the second and subsequent stitches. Can be reliably prevented.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a multi-needle type embroidery sewing machine according to an embodiment of the present invention.

FIG. 2 is a block diagram of a control system of a multi-needle type embroidery sewing machine.

FIG. 3 is a diagram showing a movement locus of a sewing needle and a movement locus of a balance.

FIG. 4 is a control program for sewing control at the start of sewing.

FIG. 5 is a control program for cloth feed control.

FIG. 6 is a control program for lock stitch control.

FIG. 7 is a partially enlarged view of the sewing mechanism and the upper thread in a rotation phase of about 120 °.

FIG. 8 is a partially enlarged view of the sewing mechanism and the upper thread in a rotation phase of about 180 °.

[Explanation of symbols]

1 Multi-needle embroidery sewing machine 6 needle bars 7 sewing needles 7a eye hole 9 Balance 11 sewing machine motor 15 rotary hook 20 Y direction moving arm 21 Y direction feed motor 23 X-direction moving arm 24 X-direction feed motor 29 Upper thread 29a Upper thread portion on the balance side 29b Upper thread part on the end side 50 controller 53 CPU 54 ROM 55 RAM W processed cloth

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Claims (5)

[Claims] 1. A sewing machine in which a sewing machine including a needle bar to which a sewing needle is attached, a balance, and a rotary hook is driven by a sewing machine motor, and a cloth feeding mechanism capable of feeding and driving a work cloth by a driving force of a stepping motor; A sewing machine, comprising: a feed control means capable of controlling the cloth feed mechanism so as to feed a minute predetermined amount in the cloth feed direction in a state in which the workpiece penetrates the work cloth. 2. The feeding control means causes the cloth feeding mechanism to execute the cloth feeding of the minute predetermined amount while the sewing needle penetrates the work cloth and is descending. sewing machine. 3. The feed control means feeds the cloth by a minute predetermined amount in a direction in which the work cloth is pressed against an upper thread free end or an upper thread portion continuing to the stitch side through a stitch hole of a sewing needle. The sewing machine according to claim 1 or 2, which controls a feeding mechanism. 4. The feed control means causes a cloth feed mechanism to execute the cloth feed of the minute predetermined amount when sewing one or a plurality of stitches after starting or resuming sewing. The sewing machine according to any one of 1 to 3. 5. The sewing machine is an embroidery sewing machine, and the feed control means is provided for thread cutting, color change of the upper thread, and thread cutting after thread cutting.
The cloth feed mechanism is caused to execute the cloth feed of the minute predetermined amount when sewing needles or plural needles.
The sewing machine according to any one of 1.