JP2792066B2 - Sewing machine feed amount correction device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a feed amount correcting device for a sewing machine, and more particularly to a feed error of an actual feed pitch amount with respect to a set feed pitch amount by trial sewing of a work cloth. And correcting the control amount of the feed stepping motor based on the feed error at the time of actual sewing of the work cloth.

[Conventional technology]

Generally, in an electronic zigzag sewing machine, a needle bar up / down drive mechanism for vertically moving a needle bar, a swing drive mechanism for swinging the needle bar left and right, and a swing stepping motor for driving the swing drive mechanism are provided as arms. A vertical feed drive mechanism for moving the feed dog up and down, a feed drive mechanism for moving the feed dog back and forth, and a stepping motor for driving the feed drive mechanism The stitches are built into the bed portion, and in addition to straight stitching and zigzag stitching, a plurality of types of sewing such as stitch stitching such as overlock stitching and pattern stitching such as characters and marks including hiragana can be performed.

Therefore, when sewing patterns such as the alphabet “O” and “Q”, the numbers “8” and “0”, and other loop-shaped marks, among various pattern sewings, the starting point of the pattern sewing is And the end point at which pattern stitching is ended by executing forward stitching and reverse stitching.

Generally, a feed adjuster is provided in the front-rear feed drive mechanism,
In a sewing machine that controls the feed stepping motor to change the inclination of the feed adjuster, the feed amount of the feed adjuster is “0”.
It is a principle that the rotation position corresponding to the above and the origin position of the feed stepping motor exactly match. Therefore, at the factory shipment stage, the worker adjusts the feed adjuster and the feed stepping motor to have the above-described positional relationship.
The mounting position of the stepping motor is adjusted for each sewing machine.

On the other hand, when a linear actuator such as a servomotor is used instead of the feed stepping motor, the drive voltage for driving the linear actuator is “0”.
The operation of adjusting the drive voltage is performed so that the position of the volts corresponds to the position of the feed amount “0” of the feed adjuster.

Recently, a sewing machine that can display a feed pitch amount and a needle swing pitch amount set for the convenience of an operator on a display numerically has also been commercialized.

[Problems to be solved by the invention]

As described above, in the sewing machine in which the inclination of the feed adjuster is controlled by the stepping motor or the linear actuator to feed the work cloth forward or backward, the mounting position of the stepping motor or the "0" volt point of the driving voltage at the factory shipment stage. There is a problem that an adjustment operation for finely adjusting the adjustment must be performed, and a great deal of labor and time is required for the adjustment operation.

Even if adjustments are made at the time of shipment as described above, it is difficult for the actual feed pitch to exactly match the set feed pitch due to manufacturing accuracy and mounting errors of parts, and particularly, sew a work cloth having a large expansion and contraction rate. Sometimes, in the case of straight stitching or zigzag stitching, it is necessary to set the value by relying on the feed pitch amount in anticipation of the feed pitch error by repeating trial sewing, etc. There are problems such as large deformation.

Furthermore, when play occurs in the drive system of the feed drive device due to long-term use of the sewing machine, a beautiful pattern cannot be sewn, and the drive system must be readjusted periodically.

The object of the present invention is, regardless of the type of work cloth to be sewn,
It is an object of the present invention to provide a sewing machine feed amount correcting device capable of reliably moving a work cloth forward or backward at a set feed pitch amount.

[Means for solving the problem]

As shown in the functional block diagram of FIG. 1, the sewing machine feed amount correcting device according to the first aspect of the present invention is provided with a needle bar having a sewing needle attached to a lower end thereof, which can move up and down, and a needle bar which moves up and down. In a sewing machine provided with a feed mechanism for transferring a work cloth by a feed dog and a feed stepping motor for driving the feed mechanism, a feed pitch setting means for setting a feed pitch for sending the work cloth when sewing the work cloth Mode setting means for selectively setting a sewing mode in which the work cloth is actually sewn and a trial mode in which the work cloth is sewn trially, and detecting a front end and a rear end thereof while sewing the work cloth in the trial mode. Detecting means, pulse generating means for outputting a predetermined number of pulses per one rotation of the upper shaft of the sewing machine in synchronization with rotation of the upper shaft of the sewing machine, and detecting when the front end of the work cloth is detected by the detecting means and the rear end thereof Between that time and Counting means for counting the pulses output from the loosening means, and the number of pulses from the counting means, a predetermined number of pulses, and the front end of the work cloth previously input in forward sewing or reverse sewing in the trial mode set by the setting means. The actual feed pitch amount is calculated based on the distance between the feed pitch and the rear end, and the feed per unit amount of the set feed pitch amount is calculated based on the actual feed pitch amount and the feed pitch amount from the feed pitch amount setting means. Calculating means for calculating an error; storing means for storing data of the feed error obtained by the calculating means; and a control amount of the feed stepping motor based on the feed error data of the storing means in the sewing mode set by the mode setting means. And correction control means for correcting

A feed amount correcting device for a sewing machine according to a second aspect of the present invention includes a needle bar on which a sewing needle is attached at a lower end and which can move up and down; In a sewing machine including a stepping motor for feeding that drives the feed mechanism, a feed pitch amount setting unit that sets a feed pitch amount for feeding the work cloth when sewing the work cloth,
Mode setting means for selectively setting a sewing mode in which the work cloth is actually sewn and a trial mode in which the work cloth is trially sewn; and a front mark marked on the work cloth while sewing the work cloth in the trial mode. Detecting means for detecting a line and a rear mark line; pulse generating means for outputting a predetermined number of pulses per rotation of the sewing machine upper shaft in synchronization with rotation of the upper shaft of the sewing machine; Between a point in time when the set mark line is detected and a point in time when the rear mark line is detected, counting means for counting the pulses output from the pulse generating means, and from the counting means in the forward stitching or the reverse stitching in the trial mode. The actual feed pitch amount is calculated based on the number of pulses, the predetermined number of pulses, and the length between the front mark line and the rear mark line of the work cloth previously input. A calculating means for calculating a feed error per unit quantity of setting the feed amount of pitch on the basis of the feed pitch amount from the actual feed pitch amount and feed pitch amount setting means,
Storage means for storing data of the feed error obtained by the arithmetic means, and correction control means for correcting the control amount of the feed stepping motor based on the feed error data in the storage means in the sewing mode. .

[Action]

In the sewing machine feed amount correcting device according to the first aspect, when the trial mode is set alternatively by the mode setting means, the counting means uses the detecting means during the forward sewing or the reverse sewing of the work cloth. Between the time when the front end is detected and the time when the rear end is detected, the number of pulses output from the pulse generation means is counted, and the number of pulses is output to the calculation means. The calculating means first calculates the number of feeds based on the number of pulses and a predetermined number of pulses per rotation of the upper shaft of the sewing machine, and calculates the number of feeds and the length between the front end and the rear end of the work cloth input in advance. The actual feed pitch amount is obtained based on the actual feed pitch amount, and the feed error per unit amount of the set feed pitch amount is obtained based on the actual feed pitch amount and the set feed pitch amount from the feed pitch amount setting means. The data is supplied to the storage means. The storage means stores the data of the feed error.

On the other hand, when the sewing mode is alternatively set by the mode setting means, the correction control means reads out the forward stitching error data stored in the storage means at the time of forward stitching, and changes the control amount of the feed stepping motor to the forward stitching amount. In addition to the correction based on the error data, at the time of reverse stitching, the reverse stitching error data stored in the storage means is read out, and the control amount of the feed stepping motor is corrected based on the reverse stitching error data.

As a result, when forming various stitches by forward stitching or backward stitching, the work cloth is reliably fed by a feed amount equal to the pitch amount set by the feed pitch amount setting means.

In the sewing machine feed amount correcting apparatus according to the second aspect, the detecting means detects a front mark line and a rear mark line marked on the work cloth instead of the front end and the rear end of the work cloth, and the calculating means performs the processing. The sewing machine according to the first aspect, which differs from the first aspect only in that the length between the front mark line and the rear mark line is used instead of the length between the front end and the rear end of the cloth. It works in substantially the same way as the quantity correction device.

〔The invention's effect〕

According to the feed amount correcting device for a sewing machine according to the first aspect,
As described above, by sewing the work cloth of the same kind as the work cloth to be actually sewn in advance in the trial mode by forward stitching or backward stitching, the unit amount of the set feed pitch amount during forward stitching and reverse stitching is set. Find the feed error per hit,
Based on these error data, the feed pitch amount at the time of sewing is reliably corrected at the time of forward feed and at the time of reverse feed, so that there is almost no need to adjust the mounting position of the stepping motor for feed or the drive voltage of the linear actuator, Also, since the feed pitch amount is automatically corrected in consideration of the play of the drive system of the feed drive mechanism caused by long-term use of the sewing machine,
The cost can be reduced and a non-adjustable sewing machine can be realized.

Furthermore, various desired patterns can be neatly sewn on various types of work cloths regardless of the expansion ratio.

According to the feed amount correcting device for a sewing machine according to the second aspect,
In addition to obtaining the same effects as those of the first aspect,
Since a pair of front and rear mark lines can be marked on the work cloth for sewing at predetermined intervals in the front and rear,
When the length between the front and rear ends of the work cloth is large, it is unnecessary to perform sewing in the trial mode unnecessarily or to prepare a work cloth for trial.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is an application of the present invention to an electronically controlled zigzag sewing machine that can perform cloth edge copying and sewing.

As shown in FIG. 2, in the arm 2 of the sewing machine M,
A needle bar vertical drive device for moving the needle bar 12 up and down, and the needle bar 12
A needle bar swing drive unit for swinging the work cloth W in the left-right direction and a balance drive unit are incorporated, and a vertical feed drive unit for moving the feed dog 20 for feeding the work cloth W up and down in the bed unit 4 is provided. The needle bar 12 is driven by a needle bar swing stepping motor 57 (see FIG. 4) via the needle bar swing drive device. Let it. Similarly to the one disclosed by the applicant of the present invention in Japanese Patent Application Laid-Open No. 61-276591, a forward / backward drive device is provided with a feed adjustment mechanism comprising a feed adjuster and a square piece (not shown). The tilt angle, that is, the cloth feed amount is changed according to the control amount of the feed stepping motor 58 (see FIG. 4) connected to the feed adjuster. The needle bar vertical drive device, the balance drive device, and the vertical feed drive device are driven by a sewing machine motor 56 (see FIG. 4).

A sewing needle 14 is attached to a lower end of the needle bar 12, and a presser foot 18 is detachably attached to a lower end of a presser bar 16 disposed immediately behind the needle bar 12.

As shown in FIGS. 2 and 3, the presser foot 18 and the needle plate 32
Is formed with a long needle hole 22 in the left-right direction. The needle hole
Detector 26 is arranged in front of right and left in the direction of right and left,
When the detector 26 is attached to the bed 4 at its base end, the detector is located on the presser foot 18, and a rectangular opening 24 is formed in the presser foot 18 in opposition to the detector 26. Have been. The detector 26 includes a CCD-type linear image sensor 2 in which a plurality of (for example, p) CCDs (charge coupled devices) having light receiving portions directed downward in a direction orthogonal to the feed direction are arranged in a line in the left-right direction.
8 (hereinafter referred to as a sensor), and a light source (not shown) for projecting light is mounted near the sensor 28. A plurality of slits are formed in the needle plate 32 provided in the bed portion 4, and the feed dog 20 can project upward from the needle plate 32 through the slits.

A start / stop button 34 for starting or stopping the sewing operation is provided on the head 8 as shown in FIG. 2, and the machine frame 10 of the pillar 6 is provided with a numeric keypad for selecting a desired sewing pattern. A pattern selection switch 36, a feed pitch adjustment knob 38 for arbitrarily adjusting the feed pitch of the work cloth W during pattern sewing, and a needle swing adjustment knob 40 for arbitrarily adjusting the swing of the sewing needle 14. Speed volume knob that can change the sewing speed from low to high
42. A mode setting knob 44 for selectively setting a sewing mode in which the work cloth W is actually sewn or a trial mode in which the work cloth W is sewn on a trial basis to obtain a feed error is provided.

Further, the arm 2 is provided with a feed pitch of 0.5 m when performing linear sewing or zigzag sewing other than pattern sewing.
Increment ski 45 to increase by m, decree key 46 to decrease the set feed pitch by 0.5 mm, increment ski 47 to increase the set needle swing by 0.5 mm, and set the needle swing by 0.5 mm There are provided a decreescue 48 for decreasing the number, a display 49 made of LEDs for respectively displaying the set feed pitch amount and the set needle swing amount, and the like. This sewing machine M is provided with a volume for setting a scanning width of a cloth edge copying, a sewing start switch, and the like.
When the copying start switch is operated, the cloth edge sewing can be performed based on the distance from the cloth edge set by the copying width setting volume. This copying sewing is similar to the cloth edge copying sewing of a normal sewing machine, and therefore, detailed description thereof is omitted.

Next, the overall configuration of the control system of the sewing machine M will be described with reference to the block diagram of FIG.

The input / output interface 63 of the control device C is connected to the following switches and volume as input signals.

Increeski 45/47 and Decreeski 46/48,
A start / stop switch 34a connected to the start / stop button 34 for outputting a start signal and a stop signal, a pattern selection switch 36 for selecting a desired pattern, and an "H" level mode in the trial mode when connected to the mode setting knob 44 A mode setting switch 44a that outputs a signal, and outputs a mode signal of “L” level in the sewing mode; a detector 26 that sequentially outputs a detection signal from each of the p pixels constituting the sensor 28 in time series; An A / D converter 26a for A / D converting a signal from the detector 26, a feed pitch adjustment knob 38a connected to a feed pitch adjustment knob 38 for outputting a feed pitch adjustment signal, and an A / D converter A / D converter 5 for D conversion
3.Connected to the needle swing adjustment knob 40a that is connected to the needle swing adjustment knob 40 and outputs the needle swing adjustment signal, and the A / D converter 54 that A / D converts the signal, and the speed knob 42. A speed volume 42a for outputting a set speed signal, an A / D converter 55 for A / D converting the signal, and a predetermined number of slits and openings formed at equally divided circumferential positions are attached to the upper shaft of the sewing machine. Pulse generator 50, which comprises a disk and a photo interrupter, and generates a predetermined number (for example, 100) of pulses per rotation of the upper shaft of the sewing machine in synchronization with the rotation of the upper shaft of the sewing machine, and a disk attached to the upper shaft of the sewing machine. Feed timing signal generator 51 which outputs a cloth feed timing signal (pulse signal) at predetermined timings in synchronism with the rotation of the upper shaft (not shown) of the sewing machine, and a photo interrupter. Like the signal generator 51, a needle swing timing signal generator 52, which is composed of a disk and a photo interrupter and outputs a needle swing timing signal (pulse signal) at predetermined timings in synchronization with the rotation of the upper shaft of the sewing machine, etc. It is connected.

By supplying a clock signal from the control device C to the sensor 28, the detector 26 sequentially outputs p charge amount signals, that is, detection signals (detection pulse signals) from the first pixel in time series. Accordingly, an “L” level detection signal is output from each pixel facing the work cloth W, and an “H” level detection signal is output from each pixel not facing the work cloth W. Further, the sewing machine motor 56 is driven via a drive circuit 59,
The needle bar swinging stepping motor 57 is connected to an input / output interface 63 via a drive circuit 60, the feed stepping motor 58 via a drive circuit 61, and the display 49 via a drive circuit 62.

The control device C includes a CPU (central processing unit) 64, an input / output interface 63, a ROM (read only memory) 65 and a RAM (random access memory) 70 connected to the CPU 64 via a data bus 67. It is composed of

The ROM 65 stores needle position data for determining a needle position (position of the sewing needle 14 inserted into the work cloth W) for each of a large number of patterns such as characters, symbols, and marks, that is, the needle bar 12.
Swing position data to specify the swing direction and swing position, feed amount of the feed dog 20 and feed amount data to specify the feed direction are associated with the pattern numbers, and are stored in advance in the pattern data, the selected pattern data. A control program for controlling the feed stepping motor 58 and the needle bar swing stepping motor 57 based on the timing signals from the cloth feed timing signal generator 51 and the needle swing timing signal generator 52, respectively.
A control program for controlling the driving of the sewing machine motor 56 based on the set speed signal output from the speed potentiometer 42 and the start signal and the stop signal output from the start / stop switch 34a, and the control amount of the feed stepping motor 58 described later. A feed pitch amount correction control program to be corrected is stored.

The feed pitch correction control program includes a feed pitch setting control program for setting a feed pitch for feeding the work cloth W by operating the increment ski 45 or the decrees key 46, and detecting the start of sewing in the trial mode. Based on the p detection signals input in time series from the detector 26,
When the front end of the trial cloth w is located below the detector 26, most of the p detection signals change from the "H" level to the "L" level at the time of forward feed, and most of the "L" level at the time of reverse feed. From the "H" level to the "H" level to detect the front end of the trial cloth w (see FIG. 7). When the rear end of the trial cloth w is located below the detector 26, It is detected that almost all of the p detection signals change from "L" level to "H" level at the time of forward feed, and almost all of them change from "H" level to "L" level at the time of reverse feed. A cloth end detection program for detecting the rear end of the cloth w, data of the number of pulses N output from the pulse generator 50 per rotation of the upper shaft of the sewing machine, and a front end of the trial cloth w to be sewn in trial in the trial mode. Length L between rear ends (for example, 100m
m) data, pattern data, a feed table for calculating the number of pulses for stepping the feed stepping motor 58 based on the set feed pitch amount, data of an initial feed pitch (for example, 2.0 mm), and the like. ing.

In the RAM 70, a sewing direction flag memory 71 for storing a sewing direction flag F for storing a sewing direction instructed when sewing the work cloth W, and set feed pitch data B set by the feed pitch amount setting control program are stored. Set feed pitch data memory 72, a count value memory for sequentially counting pulses input from the pulse generator 50 between the time when the front end of the trial cloth w is detected by the cloth end detection program and the time when the rear end is detected. 73, a forward error data memory 74 for storing error data in forward stitching, a reverse error data memory 75 for storing error data in reverse stitching,
Various memories for temporarily storing the result of the arithmetic processing by the CPU 64 are provided. When the sewing direction flag F is set, the feed direction is forward, and when the sewing direction flag F is reset, the feed direction is reverse. The mode setting switch 44
When the mode signal of the “H” level is output from “a”, the cloth edge copying control is forcibly stopped.

Next, the routine of the feed pitch amount correction control performed by the control device C of the sewing machine M will be described with reference to the flowcharts of FIGS. 5 (a) and 5 (b), and the flowchart of FIG. It will be described based on FIG. The trial cloth w to be sewn on a trial basis in the trial mode is of the same type as the work cloth W to be actually sewn as shown in FIG. 7, and is located between the presser foot 18 and the feed dog 20. The feed unit wa is actually fed with cloth, and the detection unit wb is provided by enlarging the feed unit wa to the right. The distance between the front end and the rear end of the detection unit wb is set to 100 mm. However, in the flowchart, Si (i = 1, 2, 3,...) Indicates each step.

When the CPU 64 outputs a reset signal when the power is turned on by operating a power switch (not shown), the ROM 65
In the feed pitch display area of the display 49, "2.0" is displayed based on the initial pitch data of the feed, and the initial pitch data is stored in the set feed pitch data memory 72, and further, each memory is reset. Initial setting is executed (S1), and feed pitch amount setting control is started.

When the feed pitch setting control is started when the power switch is turned on, every time the increment key 45 is operated once (S50), the set feed pitch data B of the set feed pitch data memory 72 is set to, for example, "0.5". (Mm) is added (S51), the added new set feed pitch data B is stored in the set feed pitch data memory 72 (S52), and the process returns to the main routine. Each time the decreeskey 46 is operated once (S53), the set feed pitch data memory 72 is operated.
For example, "0.5" (mm) is subtracted from the set feed pitch data B (S54), and the new set feed pitch data B obtained by the subtraction is stored in the set feed pitch data memory 72 (S5).
2) Return to the main routine.

When the trial mode is set by operating the mode setting knob 44, Ye is determined in S3 based on the "H" level mode signal output from the mode setting switch 44a.
Since the stop signal is output from the start / stop switch 34a while the start / stop button 34 is not operated, the determination is No in S4.

Then, as shown in FIG. 7, the front end portion of the feed portion wa of the trial cloth w is set below the presser foot 18, the presser foot 18 is lowered, and the start / stop switch 34 is operated when the start / stop button 34 is operated. A start signal is output from 34a, a drive signal is output to the sewing machine motor 56, and a YES determination is made in S4, and the count value memory 73, the forward error data memory 74, and the reverse error data memory 75 are cleared (S5). In the trial mode, for example, straight stitching is forcibly performed. Next, the sewing direction flag F of the sewing direction flag memory 71 is set, and forward feed is instructed (S6). The trial cloth w is fed by forward feed and the detection signal output from the detector 26 is used. It is determined whether the front end of the trial cloth w is detected by the cloth edge detection program (S7). When the detector 26 detects the front end of the detection portion wb of the trial cloth w, the determination is Yes in S7. When the pulse signal is input from the pulse generator 50 (S8), the count value M in the count value memory 73 is determined. Is incremented (S9), and it is determined whether or not the rear end of the detection unit wb is detected by the cloth edge detection program using the detection signal output from the detector 26 (S10). And S8 ~ S
Step 10 is repeated, and the count value M of the count value memory 73 is sequentially incremented until the detector 26 detects the rear end of the detection unit wb. When the rear end of the detection unit wb is detected, the count value M of the count value memory 73 and the pulse number N of the ROM 65
The number of feeds T required to sew 100 mm, which is the distance between the front end and the rear end of the detection unit wb, is calculated using the arithmetic expression M ÷ N.
Is calculated (S11), and based on the number of feeds T and the length L (100mm) between the front end and the rear end stored in advance in the ROM 65, the actual feed pitch of the forward feed is calculated by the equation L ÷ T. The quantity A is calculated (S12). Further, based on the actual feed pitch amount A of forward feed and the set feed pitch data B stored in the set feed pitch data memory 72, 1 m of the set feed pitch data B is calculated by the following equation (BA) ÷ B.
The forward feed error e1 per m is calculated (S13).
The feed error e1 is stored in the forward error data memory 74 (S14).

Next, when a predetermined time has elapsed after the detection of the rear end of the detection unit wb by the detector 26 and the rear end is located somewhat behind the detector 26 (S15), the sewing direction of the sewing direction flag memory 71 is When the flag F is reset and the reverse feed is instructed,
The count value memory 73 is cleared (S16). And S
17 to S22 are controlled in the same manner as S7 to S12, and the actual feed pitch amount A for the reverse feed is obtained by calculation. However, in S17, it is determined whether or not it is the rear end of the detection unit wb, and in S20, it is determined whether or not it is the front end. Further, based on the actual feed pitch amount A of the reverse feed and the set feed pitch data B stored in the set feed pitch data memory 72, 1 mm of the set feed pitch data B is obtained by an arithmetic expression (BA) ÷ B. The per-reverse feed error e2 is calculated (S23), and the feed error e2 is stored in the reverse error data memory 75 (S24). Next, the drive of the sewing machine motor 56 is stopped (S25), the sewing direction flag F of the sewing direction flag memory 71 is set, a forward feed is instructed (S26), and the process returns to S2.

Next, when the sewing mode is selectively set by operating the mode setting knob 44 in order to actually perform the sewing operation, S3 is determined based on the "L" level mode signal output from the mode setting switch 44a. Is determined to be No and the drive signal is not output to the sewing machine motor 56,
Is determined, and S2 to S3 · S27 are repeated. Then, as shown in FIG. 2, when the work cloth W is set at the sewing position and the desired pattern is selected and the start / stop button 34 is operated, a start signal is output from the start / stop switch 34a and the sewing machine motor 56 A drive signal is output, and the result of the determination in S27 is Yes, and actual sewing is started. Next, it is determined whether or not it is the cloth feed timing based on the cloth feed timing signal from the cloth feed timing signal generator 51 (S28), and the cloth feed W is fed by the current feed dog 20 at the cloth feed timing. When the feed amount Q is calculated, that is, in the case of straight stitching or zigzag sewing, the set feed pitch data B stored in the set feed pitch data memory 72 is used as the feed amount Q. When a pattern is selected, the feed amount based on the pattern data in the ROM 65 is used. The feed amount Q in consideration of the feed pitch adjustment signal from the feed pitch adjustment knob 38a is obtained by calculation (S29).

When forward feed is instructed based on the feed direction data stored in the pattern data and the sewing direction flag F of the sewing direction flag memory 71 is set (S3
0), a feed error E corresponding to the feed amount Q is calculated by an arithmetic expression Q × e1 based on the feed amount Q and the error data e1 at the time of forward sewing stored in the forward error data memory 74 (S31). A correction amount for correcting the control of the feed stepping motor 58 is obtained based on the feed error E and the feed table of the ROM 65 (S32), and the control amount of the feed stepping motor 58 is corrected based on the correction amount. (S33), and returns to S27. As a result, the inclination of the feed adjuster connected to the feed stepping motor 58 is corrected, and the work cloth W by the feed dog 20 is reliably fed by the feed amount equal to the feed amount Q.

As described above, by performing trial sewing using the same type of trial cloth w as the work cloth W to be sewn, a feed error at the time of forward sewing and a feed error at the time of reverse sewing are obtained by calculation, respectively. Since the feed amount at the time of actual sewing is corrected based on the feed error, it is possible to neatly sew various patterns desired on various work cloths irrespective of the type of the work cloth W, particularly the expansion and contraction rate of the work cloth W. it can.

Further, since the feed amount of each of the forward stitching and the backward stitching is corrected by the feed error calculated for each of the forward stitching and the backward stitching, the adjusting operation of the mounting position of the feed stepping motor 58 is hardly required. The feed pitch is automatically and reliably corrected for the forward feed and the reverse feed in consideration of the play of the drive system of the feed drive mechanism caused by long-term use of the sewing machine, thereby reducing costs and realizing a non-adjustable sewing machine. .

In the above-described embodiment, the sewing in the trial mode is performed using the trial cloth w having the length L between the front and rear ends. However, the length of the work cloth W for sewing in the front-rear direction is not too long. In some cases, sewing in the trial mode can be performed using the work cloth W. In this case, the length L between the front and rear ends of the work cloth W
May be input from the numeric keypad 36 to the memory of the RAM 70.

Further, if the forward error data memory 74 and the backward error data memory 75 are constituted by non-volatile memory, even if the sewing machine is turned off, the error data stored in the forward error data memory 74 and the backward error data memory 74 can be stored. Since the contents are not lost, there is no need to trially sew the work cloth in the trial mode every time the power supply of the sewing machine is connected.

It should be noted that the present invention can of course be applied to a sewing machine provided with a forward / reverse feed drive device for directly moving the feed stepping motor feed dog 20 forward / backward without providing a feed adjusting mechanism.

It should be noted that a detector is separately provided in an electronically controlled zigzag sewing machine in a normal sewing machine that cannot perform cloth edge copying, and the present invention can be applied to this normal zigzag sewing machine.

<Another Embodiment> In the above embodiment, the detector 26 is configured to detect the front end and the rear end of the trial cloth w in the trial mode. However, instead of this, the front mark line is previously formed on the upper surface of the work cloth W. And a rear mark line separated by a predetermined distance L (for example, 100 mm) in the direction perpendicular to the feed direction.
The sewing in the trial mode is performed using the work cloth W. The front mark and the rear mark are marked so that the contrast of the color tone of the work cloth W becomes clear using chaco paper or chaco, and the front mark line and the rear mark are determined based on a change in the level of the detection signal of the detector 26. A mark line is detected, and in S12 and S22 of the feed pitch correction control, the predetermined distance L (this is a constant stored in a program or a constant input from the numeric keypad 36 and stored in the RAM memory) is used. The feed pitch amount correction control program is configured to calculate the actual feed pitch amount A based on the program. However, the other configuration is the same as that of the above-described embodiment, and the description is omitted.

A supplementary description will be given of the correspondence between the means described in the claims and the components described in the actual examples and the other embodiments.

The feed pitch amount adjusting means includes an incremental ski 45, a decree ski 46, a feed pitch setting control (S50 to S54) shown in FIG. 6, a control device C for achieving this pitch setting control, a feed. A pitch amount adjustment volume 38 and the like.

What corresponds to the mode setting means is the mode setting knob 44 and the control device C. What corresponds to the detecting means is the CCD linear image sensor 28 and the control device C. The equivalent of the pulse generating means is a pulse generator 50
It is.

What corresponds to the counting means is S8 to S10 in FIG.
And S18 to S20 and the control device C. Those corresponding to the calculating means are S11 to S13 and S21 to S23 in FIG. What corresponds to the storage means is the forward error data memory 74, the reverse error data memory 75, the control device C and the like. What corresponds to the correction control means are S31 to S34 in FIG. 5B and the control device C and the like.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing the configuration of the present invention, and FIGS.
FIG. 7 shows an embodiment of the present invention, FIG. 2 is a perspective view of the sewing machine, FIG. 3 is a partial perspective view showing a state in which the detector is mounted close to the presser foot, and FIG. 5 (a) and 5 (b) are schematic flowcharts of a feed pitch amount correction control routine, FIG. 6 is a schematic flowchart of a feed pitch amount setting control routine, and FIG. 7 is a trial mode. FIG. 5 is a plan view of a trial cloth sewn on a trial basis. M: sewing machine, 12: needle bar, 14: sewing needle, 20: feed dog, 26: detector, 28: linear image sensor, 38a
… Feed pitch adjustment volume, 44a… Mode setting switch, 45… Increment ski, 46… Decree ski, 50… Pulse generator, 58… Feed stepping motor, 64… CPU, 65 …… R
OM, 70… RAM, 72 …… Setting feed pitch data memory, 7
3: Count value memory, 74: Forward error data memory, 75: Reverse error data memory, C: Control device.

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Claims (2)

(57) [Claims] 1. A needle bar having a sewing needle attached to a lower end thereof and capable of moving up and down, a feed mechanism for transferring a work cloth with a feed dog in synchronization with the vertical movement of the needle bar, and a feed mechanism for driving the feed mechanism. In a sewing machine equipped with a stepping motor, a feed pitch setting means for setting a feed pitch for sending a work cloth when sewing a work cloth, a sewing mode for actually sewing the work cloth, and a trial mode for trial sewing. Mode setting means for alternatively setting the sewing machine, in the trial mode, detecting means for detecting the front end and the rear end of the work cloth during sewing, and adjusting the rotation of the upper shaft of the sewing machine to adjust the rotation of the upper shaft of the sewing machine. Pulse generating means for outputting a predetermined number of pulses per rotation; counting pulses output from the pulse generating means between a time when the front end of the work cloth is detected by the detecting means and a time when the rear end is detected. Total Means, an actual feed pitch amount based on the number of pulses from the counting means, the predetermined number of pulses, and a previously input length between the front end and the rear end of the work cloth in forward sewing or backward sewing in the trial mode. Calculating means for calculating a feed error per unit amount of the set feed pitch amount based on the actual feed pitch amount and the feed pitch amount from the feed pitch amount setting means; and A feed amount correcting device for a sewing machine, comprising: storage means for storing data; and correction control means for correcting a control amount of a feed stepping motor based on feed error data of the storage means in the sewing mode. . 2. A needle bar having a sewing needle attached to a lower end thereof and capable of moving up and down, a feed mechanism for transferring a work cloth with a feed dog in synchronization with the vertical movement of the needle bar, and a feed mechanism for driving the feed mechanism. In a sewing machine equipped with a stepping motor, a feed pitch setting means for setting a feed pitch for feeding a work cloth when sewing a work cloth, a sewing mode for actually sewing the work cloth, and a trial mode for trial sewing. Mode setting means for selectively setting a front mark line and a rear mark line marked on the work cloth during sewing of the work cloth in the trial mode, and rotation of the upper shaft of the sewing machine. And a pulse generating means for outputting a predetermined number of pulses per rotation of the upper shaft of the sewing machine, and a time when the front mark line and the rear mark line of the work cloth are detected by the detection means. In between,
Counting means for counting the pulses output from the pulse generating means; and in the forward stitching or the backward stitching in the trial mode, the number of pulses from the counting means, the predetermined number of pulses, and the front mark of the work cloth previously input. Calculate the actual feed pitch amount based on the length between the line and the rear mark line,
Calculating means for obtaining a feed error per unit amount of the set feed pitch amount based on the actual feed pitch amount and the feed pitch amount from the feed pitch amount setting means; and storing the feed error data obtained by the calculating means. A feed amount correcting device for a sewing machine, comprising: a storage unit; and a correction control unit that corrects a control amount of a feed stepping motor based on feed error data of the storage unit in the sewing mode.