JPH09108468A - Edge control sewing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an edge control sewing device with which a stitch pitch and a margin to sew up can be surely sewn while matching them with the edge of cloth regardlessly of the curvature of form of cloth edge or the directivity of curve. SOLUTION: A 1st control means 34 controls the feeding amounts and differential amounts of feeding wheels 4 and 5 and a side wheel 16 corresponding to the sitch pitch based on the curvature form data of cloth edge detected by edge detecting means 26 and 27. Then, the fixed 'stitch pitch' is provided by preventing 'pitch nonuniformity' corresponding to the curvature form of cloth edge regardlessly of difference in the size of curvature of cloth edge form or the direction of curve, and a 2nd control means sets the upper limit of differential feeding amount of the side wheel 16 corresponding to the curvature of cloth edge. Then, the satisfactory stitch pitch and, margin to sew up are secured regardlessly of the size of curvature of cloth edge and the direction of curve by preventing problem such as the generation of 'stitch nonuniformity' since the side wheel 16 too much reacts to ruggedness which is not the original curvature form of cloth.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an edge control sewing device for maintaining a constant seam allowance.

[0002]

2. Description of the Related Art Conventionally, the curvature shape of the material edge is detected,
An edge control sewing device has been proposed in which a feed wheel is differentially operated based on the detected data to feed the material in accordance with the curvature shape of the material edge. For example, in U.S. Pat. No. 3,925,713, side wheels are arranged in parallel with a predetermined distance from a feed wheel provided near the needle drop point, and a predetermined sewing is performed by applying a differential according to the material end shape to the side wheels. An apparatus for feeding dough to obtain a bill is disclosed. In the US Pat. No. 3,925,713, the feed wheel near the needle drop point is
It is configured to always rotate at a constant feed amount according to the preset stitch pitch amount, and the differential feed amount of the side wheels is controlled based on the detection data of the curvature shape of the material edge. By doing so, the fabric is configured to be fed according to the curvature shape of the fabric edge.

[0003]

However, in such a conventional edge control sewing device, as described above, the feed amount of the feed wheel is set to be always constant with respect to the preset stitch pitch. Therefore, the material feed speed at the needle entry point itself fluctuates due to the size of the curvature in the material end shape and the difference in the direction of the curve (out curve, in curve), etc., and "uneven stitch pitch" can occur. There is a problem. In addition, even minute irregularities such as fluff that are not the original material edge shape are recognized as the material edge shape and the side wheel is differentially applied as it is, so the side wheel reacts excessively, and so-called "stitch Is caused, and the seam defect is conspicuous especially in the case of straight stitching.

In view of the above problems, the present invention prevents "stitch unevenness" and obtains a constant stitch pitch regardless of the curvature of the material end shape and the difference in the direction of the curve. It is an object of the present invention to provide an edge control sewing device capable of feeding a material and obtaining a good seam free from "sew-over".

[0005]

In order to achieve the above object, an edge control sewing device according to a first aspect of the present invention has a sewing needle which moves up and down at a predetermined needle drop position and a cloth by rotating while being in contact with the cloth. Are fed in a direction orthogonal to the sewing needle, edge detection means for detecting the curvature shape of the material edge, and are arranged in parallel at a predetermined distance from the feed wheel, and the material is fed along the curvature shape of the material edge. Thus, in the edge control sewing device provided with the side wheel for giving a predetermined differential to the feed wheel to obtain a predetermined seam allowance, the curvature shape of the material end detected by the edge detecting means is stored. Storage means, first control means for controlling the feed amount of the feed wheel so as to obtain a constant stitch pitch based on the curvature shape data of the material edge, and the curvature shape of the material edge The differential feed amount of the side wheels is controlled so as to obtain a predetermined seam allowance based on the data, and the upper limit value of the feed amount of the side wheels is set according to the curvature shape of the material end, and the upper limit is set. It is configured to have a second control means for controlling the differential feed amount of the side wheels so as not to exceed the value.

According to a second aspect of the present invention, in addition to the edge control sewing device according to the first aspect, the edge detecting means has a material edge detector protruding toward the material edge and constantly contacting the material edge at least during the sewing operation. It is composed of a tension meter and configured to detect the curvature shape of the material edge based on the amount of movement of the material edge detector.

According to the edge control sewing device as described in each of the claims, the rotation speed of the feed wheel adjusted in accordance with the set sewing pitch amount is set so that the curvature of the material end shape and the direction of the curve are changed. Since the material is fed so that it has a constant stitch pitch without causing "uneven stitch pitch", the material edge is differentially fed by the side wheels according to the curvature shape. Since the upper limit of the amount is set, even in the case of straight line stitching, even if minute irregularities such as fluff that are not the original fabric edge are recognized as the edge shape of the material, there is no excessive differential reaction in response to the minute irregularities. Good seams can be obtained without causing "sealing".

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a sewing machine provided with an edge control sewing device according to an embodiment of the present invention, in which a needle bar 2 arranged so as to project from a head 1 in a substantially vertical downward direction is a needle bar (not shown). The sewing needle 3 attached to the tip of the needle bar 2 is configured to pass through a material (not shown) at a needle drop point while being vertically moved by a drive system.

On the other hand, in the vicinity of the needle drop point, upper feed wheels 4 that rotate while making contact with the upper surface of the cloth and lower feed wheels 5 that rotate while making contact with the lower surface of the cloth are provided as material-supplying wheels. Has been. The upper feed wheel 4 and the lower feed wheel 5 are configured to rotate about an axis in a substantially horizontal direction orthogonal to the sewing needle 3 when the sewing needle 3 is in the raised position. The material is fed by the wheels 4 and 5 by the stitch pitch.

The upper feed wheel 4 is rotatably supported by a substantially cylindrical bracket 6, and a lower end portion of a bevel gear shaft 7 extending obliquely upward from the upper feed wheel 4 and a bevel gear (not shown). Are connected so as to obtain rotational driving force in the direction orthogonal to the axis. The upper end portion of the bevel gear shaft 7 is connected to the output shaft of the upper feed wheel drive motor 9 housed in the head 1 via a coupling 8, and the rotational drive force of the upper feed wheel drive motor 9 is connected. The upper feed wheel 4 is configured to perform a rotary feed operation. The bracket 6 is connected by a connecting plate 11 so as to move up and down integrally with a material presser 10 that is moved up and down by a presser lifting mechanism (not shown).

On the other hand, the lower feed wheel 5 is housed in the lower space of the needle plate (not shown), and the upper outer peripheral surface of the lower feed wheel 5 comes in contact with the lower surface of the cloth from the upper surface of the needle plate. It is arranged to project slightly. The outer peripheral surface of rotation of the lower feed wheel 5 is connected to a bevel gear shaft 13 via a bevel gear 12. The bevel shaft 13
Is connected to the output shaft of the lower feed wheel drive motor 15 stored in the lower space of the needle plate via the coupling 14, and is fed downward by the rotational drive force of the lower feed wheel drive motor 15. The wheel 6 is configured to be rotated and fed.

As described above, the upper feed wheel 4 is rotated by the upper feed wheel drive motor 9 housed in the head 1, and the lower feed wheel 5 is housed in the lower space of the needle plate. It is rotated by the feed wheel drive motor 15. And when the upper feed wheel 4 contacts the upper surface of the cloth,
While the lower feed wheel 5 is in contact with the lower surface of the cloth, the two feed wheels 4 and 5 rotate while being pressed against each other from the upper and lower surfaces of the cloth,
The dough is fed by the amount corresponding to the rotation amount. At this time, the two feed wheels 4 and 5 are configured to rotate while controlling the rotation speed according to the shape and curvature of the curve of the material edge while being controlled by the control means which will be described later, to perform material feeding.

A side wheel 16 is disposed at a position axially spaced from the lower feed wheel 5 so as to rotate in the same direction as the lower feed wheel 5. The side wheel 16 is
It is fixed to a rotary shaft 17 extending coaxially with the lower feed wheel 5, and a large diameter driven sprocket 18 is fixed to the rotary shaft 17. A rotary shaft 20 of a side wheel drive motor 19 is arranged below the rotary shaft 17 so as to rotate in parallel with the rotary shaft 17 and in the same direction as the rotary shaft 17. The small-diameter drive sprocket 21 fixed to the end of the rotary shaft 20 of the motor 19 is connected to the driven sprocket 18 and the timing belt 22 described above. The rotational force of the side wheel drive motor 19 is controlled by a control means described later in accordance with the curvature shape of the material edge, and the controlled rotational drive force is applied from the drive sprocket 21 to the timing belt 22. Is transmitted to the driven sprocket 18 via the rotary shaft 17, and the side wheels 16 are rotated together with the rotary shaft 17 while being differentially applied to the lower feed wheel 5 so as to obtain a predetermined seam allowance. There is.

On the upper side with the side wheel 16 and the cloth sandwiched,
One end of the material pressing plate 23 is arranged so as to contact and separate in the vertical direction. The material pressing plate 23 is a plate-shaped member extending from the side wheel 16 in the axial direction of the rotary shaft 17 by a predetermined distance, and the end of the material pressing plate 23 on the side away from the side wheel 16 is the base 24. It is pivotally attached so as to swing vertically. An output shaft of a cylinder 25 fixed to a base 24 is connected to the middle of the material pressing plate 23 from below, and the cylinder 25 moves up and down to move the material pressing plate 23 up and down. The oscillating end portion of the material pressing plate 23 is configured to be pressed against or separated from the material side.

Although the material is fed from the front side to the back side in FIG. 1 by the structure of the both feed wheels 4, 5 and the side wheels 16 as described above, the sewing needle 3 descends on the material at the needle drop point. In the foreground, a material edge detector 26 that contacts the material edge of the material
Is arranged. The material edge detector 26 projects toward the material edge from a potentiometer 27 as an edge detecting means for detecting the material edge shape, and is positioned on the material edge side so as to always contact the material edge at least during the feeding operation of the material. It is urged toward. The potentiometer 27 converts the fluctuation of the material edge position into a current and outputs the current by the material edge detector 26. By detecting the movement amount of the material edge detector 26 with the potentiometer 27, It is configured to recognize the curvature shape of the material edge and the direction of the curve.

The material edge detection signal thus output from the potentiometer 27 is sent to a central processing unit (hereinafter referred to as CPU) 29 via an A / D converter 28, as shown in FIG. It is input and stored in the storage means 30 as the curvature shape data of the material edge. Also above CP
A position detection signal from an encoder 31 that detects the rotational position of the sewing machine spindle and a control timing signal from the sewing machine control device 32 are input to U29. Furthermore, a timer 33 is connected to the CPU 29 so that the control operation performed by the control means described later is turned on / off at a predetermined timing.

Further, the CPU 29 feeds the vertical feed wheels 4 and 5 on the basis of the material edge detection signal output from the potentiometer 27 as the edge detecting means, that is, the curvature shape data signal of the material edge. And a second control means 35 for controlling the differential feed amount of the side wheels 16 so as to obtain a predetermined seam allowance. Then, from the first control means 34, predetermined drive command signals are sent to the above-mentioned upper feed wheel drive motor 9 and lower feed wheel drive motor 15 by the drive circuits 36 and 37.
And a predetermined drive command signal from the second control means 35 to the side wheel motor 19 through the drive circuit 38.

Next, the control function of the vertical feed wheels 4, 5 by the first control means 34 and the control function of the side wheels 16 by the second control means 35 will be described. First, FIG. 3 shows a state in which the curvature shape of the material edge is curved leftward toward the front in the material feeding direction, and the symbol S0 in FIG.
The feed amount of the side wheel 16, S1 is the feed amount of the vertical feed wheels 4 and 5, R is the radius of curvature of the material edge, d is the center distance between the side wheel 16 and the vertical feed wheels 4 and 5, and b is the vertical feed wheel. The distance between the center of 4, 5 and the needle drop point, t is the amount of seam allowance from the needle drop point to the material end, S is the set stitch pitch amount, and p is the distance from the needle drop point to the material end detector 26. The distance in the material feeding direction, a represents the distance from the center of the vertical feed wheels 4 and 5 to the material edge, and q represents the movement amount of the material edge detector 26. When these are expressed by mathematical expressions, the following relationships are established.

[0019]

(Equation 1) Then, substituting equations (1) and (2) into equation (3),

(Equation 2) And substituting equations (1) and (2) into equation (4),

(Equation 3) Becomes

By detecting q in this way,
Since the feed amounts of the vertical feed wheels 4 and 5 are obtained by the equation (5) and the differential feed amount of the side wheels 16 is obtained by the equation (6), calculations corresponding to these equations (5) and (6) are obtained. The first control means 34 and the second control means 35 have functions, respectively. Further, the second control means 35 divides the material edge into a plurality of blocks in the longitudinal direction according to the curvature shape of the material edge, as described in detail in the flow chart described later, and the side wheels 16 are provided for each block. Set the upper limit of the feed amount of the side wheel 1 so that it does not exceed the upper limit.
6 has the function of regulating the differential feed amount.

According to the edge control sewing apparatus according to the embodiment of the present invention as described above, the material to be sewn is fed from the first needle to the final needle without performing the sewing operation, and thereby the edge is sewn. The material edge detection signal output from the potentiometer 27 as the detection means is stored in the storage means 30 as the material edge curvature shape data from the first needle to the last needle. Then, based on the cloth edge curvature shape data, the cloth feeding operation and the sewing operation are executed as follows. First, the procedure for detecting the material edge curvature shape will be described.

The material is set so that the material end is separated from the needle drop point for a predetermined time and a predetermined seam allowance is obtained. At this time, at the position before the needle drop point in the feeding direction, the material edge detector 26 is brought into contact with the material edge to set the material position at a predetermined position, and then the material presser 10 is lowered. As the material presser 10 descends, the upper feed wheel 4 descends so as to come into pressure contact with the material from the upper side, and the upper feed wheel 4 and the lower feed wheel 5 cooperate to sandwich the material from the vertical direction. Hold the dough.

At the same time, by pulling the output shaft of the cylinder 25, the material presser 23 which is in contact with the cylinder 25 is swung downward, and the material presser 23 is pressed.
The oscillating end of the cloth is brought into contact with the cloth from the upper side, and the cloth is pressed so as to clamp the cloth in the vertical direction in cooperation with the side wheels 16.

As described above, the material presser 10 and the material presser 2
3 is brought into contact with the upper surface of the cloth to press the cloth, and then the vertical feed wheel drive motors 9 and 15 are driven without needle driving.
1 drives the upper and lower feed wheels 4 and 5 to rotate, and the drive force of the side feed wheel drive motor 19 drives the side wheels 16 to rotate. The dough is sent to.

Next, when the material is fed by the amount to obtain the set stitch pitch, the vertical feed wheels 4, 5 and the side wheels 16 temporarily stop, but during this stopping operation, before the needle drop position. The detected material edge position detection signal is input from the potentiometer 27 to the A / D converter 28 via the material edge detector 26, is A / D converted by the A / D converter 28, and is input to the CPU 29. To be done. The input position detection signal of the material edge is stored in the storage means 30 as a digital curvature shape signal. Such data collection is executed from the first needle to the last needle, whereby the curvature shape data over the entire length of the material end is stored in the storage means 3.
Stored in 0.

At this time, the feed amounts of the upper feed wheel 4, the lower feed wheel 5, and the side wheels 16 are calculated by the CPU 29 based on the position detection signal of the material edge, and based on the data obtained from this calculation, A seam allowance in which the feed amount of the upper feed wheel 4 and the lower feed wheel 5 is controlled by the first control means 34 so as to always obtain a constant pitch, and the differential feed amount of the side wheel 16 is always kept constant by the second control means. Controlled to get the value.

Next, the operation of blocking the material end by the second control means 35 will be described. In the embodiment of the present invention, this blocking operation and the above-described cloth edge shape detection are performed at the same time. However, for convenience of explanation, the blocking operation is separately described using the flowcharts shown in FIGS. 4 and 5. Will be described in detail.

First, as shown in FIG. 4, the sewing needle 3
The count of the number of stitches with respect to the initial position of is set to n = 0 (step 1), and as described above, the material set at the initial position by the intermittent rotation drive of the vertical feed wheels 4, 5 and the side wheels 16 at each stitch pitch is set. The material is sent along the material edge, and while the material edge position detection signal, that is, the material edge curvature shape data is obtained, the material edge position detection signal, that is, the material edge curvature shape data obtained at the n-th stitch is smoothed. (Step 2). This smoothing is performed by three consecutive points n-1, n, n + 1.
It is carried out as follows using the detected value of the stitches.

That is, when the detected values corresponding to the nth, n-1, and n + 1th stitches are respectively set to Dn, Dn-1, and Dn + 1, the smoothed data Dfm for the nth stitch to be obtained is Dfm = Dn-1. It is represented by + Dn + Dn + 1/3.

Then, it is judged whether or not all the needle drop points have been passed (step 3), and if the current number of stitches is not the last stitch, the current number of stitches is incremented by 1 and the process returns to step 2 (step 4). Repeat this. When the current number of stitches is the final stitch, the minimum number of stitches in the block is set to Smin based on the preset maximum number of blocks (step 5).
The minimum number of stitches in this block is obtained by dividing the total number of stitches by the set maximum number of blocks. When the maximum number of block divisions is Bn and the total number of stitches is St, Smin = St / Bn expressed. However, the value of Smin is a positive number with the fractional part truncated.

Next, the number of stitches is set to n = 0, the number of blocks is set to m = 1 (step 6), and the number of stitches in the block is set to i = 0 (step 7). The average value and the standard deviation of the smoothed data up to the (i-1) th stitch (one time before the current number of stitches) are calculated for each feeding of the fabric (step 8).

Then, it is judged whether or not the i-th stitch is less than or equal to the preset minimum number of stitches in the block (step 9),
When the i-th stitch is equal to or smaller than the minimum number of stitches in the block, +1 is added to the number of stitches in block i and the total number of stitches St (step 10). On the other hand, when the number of stitches in the i-th stitch exceeds the minimum number of stitches in the block, the average value of the smoothed data up to the (i-1) st stitch is compared with the average value of the smoothed data of the i-th stitch (step 11). If the difference between the two is smaller than the preset block update determination value x, the process returns to step 8 and the same process is performed for the next needle drop.

Then, in step 11, it is determined that the difference between the average value of the smoothed data up to the (i-1) th stitch and the average value of the smoothed data up to the i-th stitch is larger than the block update determination value x. In this case, this m-th block (currently the first block
The number of stitches in the block is determined as i (step 12).

Next, after determining the number of stitches in the m-th block as described above, the displacement of the feed amount of the lower feed wheel 6 is calculated as follows from the average value data up to the (i-1) th stitch ( Step 13). That is, when the average value data up to the (i-1) th stitch is qi-1, the displacement amount of the lower feed wheel 6 is S1, and the set stitch pitch amount is S, the above-mentioned calculation function in the first control means 34 is used. By

(Equation 4) Is obtained.

After determining the feed amount of the vertical feed wheels 4 and 5 in the m-th block in this way, the upper limit value of the differential feed amount of the side wheel 16 is determined (step 14). That is, if the standard deviation data up to the (i-1) th stitch is δi-1, and the upper limit value of the differential feed displacement amount of the side wheel 16 is Sm0,

(Equation 5) Is obtained by the arithmetic function in the second control means 35 described above.

Next, it is judged whether the current total stitch count is the final stitch (step 15). If the total stitch count is not the final stitch, +1 is added to the total block count m (step 17). If the total number of stitches is the final stitch, the total number of blocks is determined to be m (step 16), and the block division data creation processing is ended.

In the present embodiment, as described above, the setting of the material feed amount for each block of the vertical feed wheels 4 and 5 and the setting of the differential feed amount of the side wheels 16 are performed without performing the actual sewing operation. Therefore, it is possible to accurately detect the edge of the material before the actual sewing operation without meaninglessly attaching the needle mark to the material.

Next, the actual sewing operation after detecting the curvature shape of the material edge and making it into blocks as described above will be described. The flow chart of FIG. 5 described in detail below describes a method in which upper and lower fabrics are sewn together, so the upper feed wheel 4 is a feed wheel for feeding the upper fabric, and the lower feed wheel 5 is Since it serves as a feed wheel for feeding the lower cloth, when the upper cloth and the lower cloth have different curvature shapes at the edges of the cloth, the respective feed amounts are different.

As shown in FIG. 5, after the cloth is first set to the initial position, the block number count K is calculated based on the curvature shape data of the cloth end up to the final needle drop position obtained as described above. While setting (step 1), the number of stitches i1 in the first block, the feed amount Uf1 of the upper feed wheel 4, the feed amount Lf1 of the lower feed wheel 5, and the upper limit value Sm0 of the differential feed amount of the side wheels 16 are set. (Step 2).

After completing the initial setting as described above, it is checked whether or not the sewing machine is rotating (step 3). If the sewing machine is not rotating, it waits for the sewing machine to rotate, and the process proceeds to the next step. After confirming that the sewing rod 2 has passed the reading position of the material edge by the position signal from 31 (step 4), the amount of movement of the material edge detector 26 is detected by the potentiometer 27 to detect the material edge. The curvature shape and the direction of the curve are recognized (step 5).

Then, the differential feed amount of the side wheels 16 is calculated by the calculation function of the first control means 34 based on the value of the displacement amount of the material edge detector 26 (step 6). Then, it is further determined whether the differential feed amount of the side wheels 16 calculated and obtained in step 6 is equal to or less than the upper limit value Sm0 set for each block as described above (step 7).
When the differential feed amount of the side wheels 16 obtained by the calculation exceeds the upper limit value Sm0, the differential feed amount of the side wheels 16 is changed to the upper limit value Sm0 (step 8) and exceeds the upper limit value Sm0. If not, the material is fed with the same differential feed amount and the process proceeds to the next step.

In the next step, it is judged whether or not the sewing machine is rotationally driven (step 9), and if the sewing machine is stopped after the last needle of the last block has been hit, thread cutting is performed to perform the sewing operation. It ends (step 10). If the sewing machine is rotating while the needle is on the way, the encoder 3
Based on the position signal from 1, it is confirmed that the sewing rod 2 has passed the reading position of the material end (step 11), and then the upper feed wheel 4, the lower feed wheel 5 and the side wheel 16 are operated with the above-described feed amount. Let (Step 12)

Then, it is judged whether or not the feeding operation of the upper feed wheel 4, the lower feed wheel 5 and the side wheel 16 has been completed (step 13). If not completed, the upper feed wheel 4, the lower feed wheel. Wait until the feeding operation of the No. 5 and the side wheels 16 is completed, and when the feeding operation is completed, it is confirmed whether the current needle drop is the last needle in the current block (step 14).
If the current needle drop is not the last stitch in the block, the number of stitches in the block is incremented by 1 (step 15), the process returns to step 3 described above, and the procedure described above is repeated.

If the current needle drop is the last needle in the block, it is confirmed whether this block is the last block (step 16), and if it is recognized as the last block,
The feed amount of the upper feed wheel 4 and the lower feed wheel 5 is adjusted to the set stitch pitch itself, and the differential feed amount of the side wheel 16 is set to a value for executing linear stitching (step 17).

On the other hand, if the final block is not recognized in step 16, the block number is incremented by 1 (step 18) and a new block is entered. Then, the number of needles in the new block is set to in, the feed displacement amount of the upper feed wheel 4 is set to Ufn, the feed displacement amount of the lower feed wheel 5 is set to Lfn, and the feed displacement amount of the side wheel 16 is set to Sfn (step 19). , And returns to step 3 described above.

As described above, according to the edge control sewing apparatus according to the present embodiment, the feed amount of the vertical feed wheels 4 and 5 adjusted according to the set sewing pitch S is equal to or smaller than the curvature of the material end shape. Since the control is performed in accordance with the direction of the curve, the material is fed so as to have a constant stitch pitch without causing "uneven stitch pitch".

Further, since the material end is divided into blocks corresponding to the curvature shape and the upper limit of the differential feed amount of the side wheels 16 is set for each block, fluffing which is not the original material end, especially in the case of straight stitching. Even if minute irregularities such as are recognized as the edge shape of the material, there is no excessive differential reaction in response to the minute irregularities, and good stitches can be obtained without causing "stitching". On the other hand, for a material edge having a large curvature and a gentle curve, a differential feed amount corresponding to that is set, so that good followability can be obtained for the material edge. Therefore, it is possible to secure a good stitch pitch and seam allowance regardless of the curvature of the material edge and the direction of the curve.

In the apparatus of the above embodiment, first, the curvature shape of the material end is detected without driving the needle bar 2 and then the actual sewing operation is started. Even in the actual sewing operation, the needle is moved up and down for each stitch of the sewing operation. Feed amount of feed wheels 4, 5 and side wheel 1
The differential feed amount of 6 is calculated, but since the curvature shape of the material edge is already recognized before the sewing operation is started, it is possible to execute the feed operation based on the curvature shape data of the material edge. In that case, the calculation in the sewing operation can be omitted.

[0049]

As described above, according to the edge control sewing apparatus of the present invention, based on the data of the curvature shape of the material edge detected by the edge detecting means, the feed amount of the feed wheel and the side wheel and the feed amount according to the stitch pitch and The differential amount is controlled by the first control means to prevent "pitch unevenness" in accordance with the curvature shape of the material edge regardless of the curvature of the material edge shape and the difference in the direction of the curve, and to maintain a constant "pitch". The second control means sets the upper limit of the differential feed amount of the side wheels in accordance with the curvature of the material edge, and the side wheels have unevenness that is not the original curved shape of the material. To prevent problems such as "stitch slippage" appearing in the seam due to excessive reaction to the like, and to secure a good stitch pitch and seam allowance regardless of the size of the curvature of the material edge and the direction of the curve Therefore, according to the present invention, If it is possible to remarkably improve the sewing machine reliability.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a configuration of an edge control sewing device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a control system of an edge control sewing device according to an embodiment of the present invention.

FIG. 3 is a principle operation explanatory view explaining the operation of the edge control sewing device in the embodiment of the present invention.

FIG. 4 is a flowchart showing a procedure for creating block division data of the edge control sewing device according to the embodiment of the present invention.

FIG. 5 is a flowchart showing a sewing operation procedure of the edge control sewing device in the embodiment of the present invention.

[Explanation of symbols]

 2 Needle bar 4 Upper feed wheel 5 Lower feed wheel 16 Side wheel 26 Material edge detector 27 Potentiometer 29 CPU 34 First control means 35 Second control means

Claims (2)

[Claims] 1. A sewing needle that moves up and down at a predetermined needle drop position, a feed wheel that feeds the cloth in a direction orthogonal to the sewing needle by rotating while contacting the cloth, and a curvature shape of the cloth end is detected. Edge detection means and a side wheel that feeds the fabric so as to obtain a predetermined seam allowance along the curvature shape of the fabric end by imparting a predetermined differential to the feed wheel at a position separated from the feed wheel by a predetermined distance. In the edge control sewing device, the storage means for storing the curvature shape of the material edge detected by the edge detecting means, and the constant stitch pitch based on the curvature shape data of the material edge are obtained. The first control means for controlling the feed amount of the feed wheel, and the differential feed amount of the side wheel are controlled so as to obtain a predetermined seam allowance based on the curvature shape data of the fabric end, and the fabric An upper limit value of the feed amount of the side wheel is set according to the curvature shape of the end, and a second control means is provided for controlling the differential feed amount of the side wheel so as not to exceed the upper limit value. A characteristic edge control sewing device. 2. The edge detecting means according to claim 1 comprises a potentiometer having a material edge detector projecting toward the material edge and contacting at least the material edge at all times during a sewing operation. An edge control sewing device configured to detect a curvature shape of a material edge based on a movement amount.