JPH04244190A - Superposed seaming method with sewing machine and data processor therefor - Google Patents

Abstract

PURPOSE:To provide an attractive embroidary by preventing knots of upper and lower threads from coming out on the surface side of a working cloth when an embroidered base cloth is subjected to superposed scanning after embroidering the base cloth region. CONSTITUTION:Contour data of a plurality of closed regions constituting patterns are stored in a storage means in association with a sewing order, and an overlapping situation of the closed regions is discriminated on the basis of the contour data (S905, S906). Tensional balance between the upper and lower thread in embroidering the closed region placed on the base cloth region is changed to set thread tension data so that the tension of the upper thread becomes weaker relatively (S907).

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a method for overlapping stitching in which a predetermined area is filled with stitches using a sewing machine and then a stitch is formed in that area again, and a data processing device for the same. be.

0002

[Prior Art] Conventionally, this type of overlapping stitching has been carried out, for example, between a needle that moves up and down and a workpiece cloth holding means that holds the workpiece cloth, based on embroidery data. This is sometimes done with an embroidery machine that generates movement to embroidery the work cloth.

[0003] In order to create embroidery data for controlling the relative movement between the needle of this embroidery sewing machine and the work cloth, a device called a so-called punching machine consisting of a personal computer and a digitizer is used. There is a method in which a pattern is pasted on a digitizer, and a person plots the outline of the pattern using a marker in a desired sewing order to convert it into block or single stitch embroidery data.

The present applicant has also proposed a data processing device for an embroidery sewing machine, which is pending in Japanese Patent Application No. 1-279381, as an alternative to punching machines. This processing device reads the outline of a closed area to be embroidered using an outline reading means for each closed area, divides the closed area into a plurality of blocks based on the outline data, and determines the sewing order for each block. This is automatically calculated by the sewing order determining means. On the other hand, thread density data and sewing order are set in advance for each closed area. Actual needle position data is calculated based on thread density data and block data according to the sewing order of the closed areas and the sewing order of blocks calculated for each closed area.

[0005] Here, embroidery is carried out using two blocks facing each other.
This is done by connecting the outline elements of the book alternately to form stitches, and the embroidery progress direction is the direction in which the pattern is filled with stitches, and is specified by, for example, numbering the coordinates of the vertices.

When the pattern to be embroidered is a trapezoid 88 shown in FIG. , numbers are assigned to the coordinates of the four vertices, and the direction of embroidery progress is specified. No. 1 is the starting point, No. 4 is the ending point, and the embroidery progresses in the direction shown by the arrow by alternately connecting the points on sides 1-3 and 2-4.

Further, when the pattern to be embroidered is a triangle 92 as shown in FIG. 12(a), two numbers are attached to one of the three vertices. The reason why two numbers are given is that during embroidery, stitches are formed by connecting the opposite sides alternately. Furthermore, in the case of a sector, a trapezoid 88
Data is formed in the same way. Note that the trapezoid includes not only a trapezoid defined by four contour line elements but also a triangle whose one side forms an arc and is defined by three contour line elements. When the pattern to be embroidered is an alphabet, a character, a symbol, a figure, etc., it may be divided into a plurality of triangles, squares, or fan shapes, and pattern data may be created for each block. In this case, the pattern includes multiple pattern data as well as
It is assumed that it has data representing the number of pattern data. When a triangle, a square, and a sector form a single pattern, the number of embroidery data is 1. Further, a block in which pattern data is created in this manner is referred to as a basic block.

Now, the needle drop position data (stitch data) for satin stitching the basic blocks shown in FIGS. 11(a) and 12(a) is calculated based on the block data and predetermined thread density data. However, the calculated needle positions are shown in FIGS. 11(b) and 12(b), respectively. Here, the needle positions are alternately determined at regular intervals on sides (contour line elements) 1-3 and sides (contour line elements) 2-4. When the length of a side (contour line element) is zero (when it is a point), the needle position is determined intensively at that point.

If the thread density is given by the number of stitches per block, it will be 11 in FIG. 11 and 13 in FIG. By setting the thread density of the block to be the value obtained by dividing the length of the midpoints by a certain predetermined value, it is possible to maintain a substantially constant stitch density for the block group as a whole.

0010

[Problem to be solved by the invention] Generally, a predetermined area (
When the fabric (base area) is filled with seams, the processed fabric tends to become stiffer, and once the processed fabric is hardened, when a needle inserted into the processed fabric comes out upwards, the hole made by the needle becomes difficult to close immediately. And the needle drop interval when overlapping stitches (for example, the stitch length for satin stitches, the pitch of fill stitches for fill stitches)
If the thread is too small, the amount of the lower thread pulled out will not be reduced beyond a certain level compared to the amount of the upper thread pulled out, but will become relatively large, making it easier for the lower thread to come out on the surface of the work cloth. In particular, when the base area is filled, the threads are sewn onto the processed fabric at regular, shorter intervals compared to satin stitching.
The degree to which the work cloth becomes stiff is significant, so if you perform overlapping stitches on top of it, the bobbin thread will be more likely to come out on the front side of the work cloth. Due to these effects, the bobbin thread tends to come out on the surface of the workpiece fabric when overlapping stitches are performed, resulting in poor appearance of the finished stitches.

Therefore, when filling the base area with stitches, the needle thread tension and bobbin thread tension are manually adjusted using the thread tension device so that the knotting point of the needle thread and bobbin thread is located on the back side of the workpiece cloth. Even if this setting is made, the knot points will come out on the front side of the workpiece fabric during overlapping stitching.

The present invention has been made to solve the above-mentioned problems, and its purpose is to prevent the knotting point of the upper thread and lower thread from appearing on the front side of the workpiece fabric when overlapping stitches are performed. To provide an overlapping stitching method for a sewing machine in which the stitched finished product has good appearance without being overlapping, and to provide a data processing device for the same.

[0013]

[Means for Solving the Problems] In order to achieve this object, a data processing device for a sewing machine according to claim 1 includes a needle that is moved up and down, work cloth holding means for holding work cloth, and sewing data. or a storage means for storing area data indicating a sewing area, and a direction intersecting the vertical movement axis of the needle between the needle and the work cloth holding means based on the sewing data or area data read from the storage means. A data processing device for a sewing machine, comprising a drive means that generates a relative movement, and a thread tension changing means that changes the tension balance between the upper thread and the lower thread based on thread tension data, the data processing device comprising: a drive means that generates relative movement; A determination means for determining whether or not there is overlap stitching in which a predetermined area is filled with stitches based on area data and then the area is sewn again; and setting means for changing and setting the thread tension data so that the tension balance of the lower thread is such that the needle thread tension is relatively weaker than the needle thread tension.

[0014] In the overlapping sewing method of a sewing machine according to claim 2, the needle which is moved up and down and the work cloth holding means for holding the work cloth are relatively moved based on sewing data related to the needle position. A sewing machine overlapping stitching method in which a predetermined area is filled with a lockstitch stitch made of upper thread and lower thread on a workpiece fabric, and then a stitch is formed in that area again. With respect to the tension balance between the thread and the bobbin thread, the tension balance when the area is once filled with stitches and then when the stitches are formed again is made different, so that the needle thread tension is relatively weaker.

[0015]

[Operation] In the data processing device for a sewing machine having the above-mentioned structure, the storage means stores sewing data related to the needle position or area data indicating the sewing area, and the determination means is stored in the storage means. Based on the stored sewing data or area data, the setting means determines whether or not there is an overlap stitch in which the area is sewn again after filling a predetermined area (base area) with stitches, and the setting means Based on the determination result, if there is overlap stitching, thread tension data is set to change the tension balance between the needle thread and bobbin thread during the overlap stitching so that the needle thread tension is relatively weaker. Based on this thread tension data and the sewing data or area data, the driving means of the sewing machine moves the needle and the workpiece cloth holding means relative to each other, and the thread tension changing means balances the tension of the upper thread and lower thread during overlapping sewing. is changed so that the needle thread tension is relatively weaker.

[0016] Here, the thread tension changing means includes a mode of weakening only the tension of the upper thread, a mode of increasing only the tension of the bobbin thread, and a mode of weakening the tension of the needle thread and strengthening the tension of the bobbin thread. . In addition, the thread tension changing means changes the clamping pressure of the thread tension disc that clamps the needle thread based on the thread tension data, and the amount of thread required to form a stitch for each stitch. This includes the manner in which the On the other hand, when changing the bobbin thread tension, for example, when a full-rotation hook is used, the bobbin thread bobbin may be magnetically attracted to the lower surface of the inner hook to provide resistance to the rotation of the bobbin thread bobbin. .

On the other hand, in the overlapping sewing method of the sewing machine according to claim 2, the needle, which is moved up and down based on sewing data related to the needle position, and the work cloth holding means for holding the work cloth are moved relative to each other, so that the needle is moved up and down based on the sewing data related to the needle position. The tension balance between the needle thread and bobbin thread when filling the area with stitches is different, and the tension balance when forming the stitches again after filling the area with stitches is different, so that the needle thread tension is relatively higher. I'm trying to get weaker.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in a data processing device for an embroidery sewing machine will be described below with reference to the drawings.

In FIG. 2, a sewing machine frame 14 is provided on a sewing machine table 10. As shown in FIG. The sewing machine frame 14 is
It consists of a pillar part 16 rising from the bed 12, and an upper arm 18 extending cantilevered from the upper end of the pillar part 16 and substantially parallel to the bed 12. This sewing machine frame 14
A needle bar 22 is attached to the needle bar 22 so as to be movable in the vertical direction via a needle bar stand (not shown), and a sewing needle 24 is fixed to the lower end thereof. The needle bar 22 is connected to a main shaft rotated by a sewing machine motor 26 (see FIG. 3) via a needle bar holder, a needle bar crank, etc., and the needle bar 22 and sewing needle 24 are reciprocated up and down by the drive of the sewing machine motor 26. I am made to do so. An opening is formed in the upper surface of the bed 12. This opening is closed by the needle plate 30, and the needle hole 38 is provided in the needle plate 30.
is formed.

Furthermore, an embroidery frame 42 as a work cloth holding means is mounted on the sewing machine table 10 and bed 12 so as to be movable in the X-axis direction, which is the left-right direction of the sewing machine, and in the Y-axis direction, which is the front-rear direction. ing. The embroidery frame 42 has an annular outer frame 44 and an inner frame 46 fitted inside the outer frame 44, and these frames 44 and 46 hold the work cloth. A slide portion 48 is formed on the outer frame 44 and extends away from the sewing machine frame 16 in the X-axis direction, and is slidably fitted into a pair of guide pipes 50 provided on the sewing machine table 10 in the Y-axis direction. has been done. Both ends of these guide pipes 50 are supported by support stands 52 and 54. One support base 52 is moved in the X-axis direction by a feed screw 56 and an X-axis feed motor 58, and the other support base 54
are spaced apart from the upper surface of the sewing machine table 10. A pair of endless wires 60 are engaged with the slide portion 48 and the supports 52 and 54, and as the wires 60 are moved by the rotation transmission shaft 62 and the Y-axis feed motor 64, the slide portion 48 is can be moved axially. The embroidery frame 42 can be moved to any position in the horizontal plane by the movement of the support base 52 in the X-axis direction and the movement of the slide portion 48 in the Y-axis direction.
Embroidery is applied to the work cloth by the vertical movement of step 4. This X
A driving means is composed of the axis feed motor 58, the Y-axis feed motor 64, and the like.

Further, an upper thread tension device 200 (see FIG. 3) is attached to the upper arm 18, and the upper thread tension device 200 passes through a pair of thread tension discs 210 to form a stepped portion 220a. An adjusting nut 230 having a driven gear carved on its outer periphery is screwed onto the adjusting threaded rod 220, and a spring 2 is inserted between the adjusting nut 230 and the thread tension plate 210.
25 is interposed therein, and a driving gear 122a fixed to the output shaft of the upper thread tension pulse motor 122 meshes with the driven gear of the adjusting nut 230.

Therefore, the upper thread tension pulse motor 122
By rotating the adjusting nut 230, the adjusting nut 230 is rotated via the drive gear 122a and moved forward and backward on the adjusting threaded rod 220, thereby changing the upper thread clamping pressure of the pair of thread tension discs 210. That is, by controlling the amount of rotation of the upper thread tension pulse motor 122, the upper thread tension is controlled to a desired value.

On the other hand, a horizontal full-rotation hook 300 (see FIG. 4) is provided below the throat plate 30 of the bed 12.
In the full-rotation hook 300, an outer hook 312 made of synthetic resin is fixed to a hook shaft 310 made of a magnetic material, and an inner hook 314 made of synthetic resin and having a bobbin storage chamber 314a formed therethrough is attached to the outer hook 312. It is rotatably housed. The lower part of this inner pot 314 has an inner pot bottom plate 314b made of a magnetic material.
is fixed. A ring-shaped excitation coil (lower thread tension device) 120 is inserted and fixed onto the shuttle shaft 310.

Therefore, when the bobbin 320 made of a magnetic material is accommodated in the bobbin storage chamber 314a of the inner hook 314 and the excitation coil 120 is excited, the bobbin 320 is attracted to the inner hook bottom plate 314b. That is, by controlling the magnitude of the current flowing through the excitation coil 120, the attraction force of the bobbin 320 is changed to a desired value, and the pull-out resistance of the lower thread is changed (the lower thread tension is changed). Incidentally, the upper thread tension pulse motor 122, the excitation coil 120, etc. constitute a thread tension changing means for changing the tension balance between the upper thread and the lower thread.

The present sewing machine is controlled by a control device 70. The control device 70 includes a CPU 72 as shown in FIG.
, a ROM 74, a RAM 76 as a storage means, a bus 78, and the like. An input interface 80 is connected to the bus 78, and a keyboard 82 and an external storage device 84 are connected to the input interface 80. The keyboard 82 is used to input the embroidery pattern to be applied to the work cloth, the pattern formation interval, the stitch density, etc. It is used for inputting data, including keys for specifying embroidery patterns such as alphabets, numbers, symbols, and kana. Various necessary keys are provided.

Further, as shown in FIG. 7, the external storage device 84 stores contour data indicating the outline of each of the plurality of closed regions P1 to P7 that constitute the pattern to be embroidered (design P0). . Here, the contour data of the closed area is set as position data of a plurality of points set on the contour line in order to define the contour line (one closed contour line). Points on this outline are called constituent points. Note that this contour data includes, in addition to the data representing the sequence of points on the contour line, the starting point,
It may also indicate a Bezier curve that expresses a free curve using an end point (the starting point and end point are in the same position because it is a single closed contour) and control points. Furthermore, the embroidery stitch start point and end point are stored for each closed area.

An output interface 100 is also connected to the bus 78 of the control device 70, and the sewing machine motor 26 and the X-axis feed motor 58 are connected to the output interface 100 via motor drive circuits 104, 106, 108 and a display drive circuit 110. , Y-axis feed motor 64 and display device 1
12 are connected. The display device 112 displays the pattern to be embroidered on the screen based on the pattern data. Further, the output interface 100 includes a power supply circuit 114.
, an excitation coil 120 and an upper thread tension pulse motor 122 are connected via a motor drive circuit 116.

Further, as shown in FIG. 6, the RAM 76 includes an outline memory, pattern data memory, thread density memory, positional relationship memory, sewing order memory, thread tension memory, sewing method memory, counter, etc. together with a working area. It is provided. Furthermore, the ROM 74 contains a program for creating needle drop data shown in the flowchart in FIG.
A closed area overlap determination routine shown in a flowchart is stored in .

Next, the operation will be explained by taking as an example the case where the thread tension in the embroidery area is changed when embroidering the pattern P0 shown in FIG. 7.

Here, it is assumed that the pattern P0 includes seven closed areas P1 to P7 as shown in the same figure, and the outline (outer shape) data of the pattern P0 is stored in the external storage device 84. It is assumed that the upper and lower thread tension, thread density, etc. are all specified to predetermined standard values.

The operator inputs a command to start this program from the keyboard 82. Then, the CPU 72 loads the outline information (contour data) of each closed area of the pattern P0 from the external storage device 84 into the outline memory of the RAM 76 (FIG. 9, step S901, hereinafter simply abbreviated as S901. The same applies to the others). Next, the process advances to S902, and the thread density of the closed area is
The position coordinates, sewing order, needle drop pitch for fill stitches, and thread tension of upper and lower threads are associated with the closed area and stored in RAM7.
6. Next, the total number of outline lines is assigned to variable N. Here, it is 7 from closed area P1 to closed area P7 (S
903). Then, the variable C is set to 1 (S904). C indicates the sewing order number of the closed area currently being processed. Next, the process proceeds to a routine (overlap determination routine S905) for determining whether there is another closed area to be sewn before the Cth closed area under the C-th closed area based on the contour data.

Next, the closed region overlap determination routine of S905 will be explained using the flowchart of FIG.

For the sake of simplicity, it is assumed here that if the upper closed region protrudes from the lower closed region even a little, the closed regions do not overlap. Of course, if only a certain area overlaps, for example 50% or more, then it is determined that they overlap, or if the closed area is made up of multiple blocks, it is also possible to determine the overlap for each block.

Now, when this routine is entered, the CPU 72
is the number of constituent points of the C-th closed region (referred to as C closed region) (
The number of contour points defining the contour of the closed region) is assigned to variable D (S1001). Here, the constituent points are points that define the outline of the closed area, and if the outline is a straight line, they are the constituent points themselves, and if the outline is a curve, they are points on the curve with sufficiently fine intervals. Next, a variable E representing the stored order of the constituent points of the C closed region and a variable F representing the closed region are initialized to 1 (S1002, S1003).

Next, the CPU 72 determines whether the Eth constituent point of the C closed region (Cth closed region) is within the Fth closed region (S1004). This determination is based on the component point E
This can be determined by checking whether any constituent sides (line segments defined by adjacent constituent points) in the F closed region are on the same side, either the right or the left. If it is determined that the area is within the closed area, the result is YES, and S1
The process proceeds to step 005, where the variable E indicating the constituent points of the C closed region is incremented, and the process proceeds to S1006, where it is determined whether or not the inside/outside determination for the F closed region has been performed for all constituent points. If NO, the process returns to S1004 and it is determined whether the next constituent point is within the F closed region. If all the constituent points continue to be within the F closed region, the determination in S1006 is YES and the process proceeds to S1007, but if even one point is outside the F closed region, the determination is NO in S1004 and the process proceeds to S10.
Proceed to step 10.

In S1010, the CPU 72 clears the overlap flag of the F closed region. This indicates that the C closed region is not included in the F closed region. After this, the CPU 72 goes to S100.
Proceed to step 8.

Further, if the determination in S1006 is YES, the CPU 72 proceeds to the process in S1007 and sets the overlap flag of the F closed region. This indicates that the C closed region is included in the F closed region. After this, the CPU 72 proceeds to the process of S1008.

[0038] In S1008, the CPU 72 increments a variable F representing a closed area, and proceeds to S1009 to determine whether all closed areas from the first to the Cth have been examined. If NO, return to S1004 and proceed to the next step. The closed region is checked, and if YES, this routine ends.

In this case, the value of C is 1, and the closed area P1 is sewn first, so the closed area P1 is sewn first.
Assume that the overlap flag is not set for 1. In other words, even if it is determined that the area overlaps with its own closed area, the overlap flag is not set.

According to the overlap determination routine S905, C
After determining whether there is another closed area to be sewn before the second closed area, the CPU 72 proceeds to S906 of the main routine. In S906, it is determined whether an overlap flag is stored for the C closed region. In this case, since the determination result in S906 is NO, the CPU 72 proceeds to the process in S908, increments the variable C, and proceeds to the process in S909. In S909, the CPU 72 determines whether the value of the variable C is greater than the number N of outline lines. That is, it is determined whether or not processing has been completed for all closed regions. Here, since the value of variable C is 1, the determination result in S909 is NO, and the CPU 72
The process returns to the overlap determination routine S905.

In this routine, the overlapping state of the closed area P2 is determined. Since the closed area P2 overlaps the closed area P1, the determination result in S906 is YES and S907
An overlap flag indicating that the closed area P1 overlaps the closed area P2 is stored in a predetermined area of the RAM 76. After that, the CPU 72 proceeds to S906, and the closed area P
Since the overlap flag is stored for No. 2, the determination result is YES, and the process advances to S907. This S90
At step 7, the CPU 72 sets the tension of the upper thread for the closed area P2 stored in the RAM 76 to 1/2 of the initial setting value, and changes the tension of the lower thread to twice the initial setting value. This is to prevent the work cloth from becoming stiff since the closed area P1 is sewn first, making it easy for the bobbin thread to come out to the surface of the work cloth, but the degree of this is 1/2, 2 It is not limited to double, but may be changed depending on the situation.

[0042] After correcting the thread tension, CPU7
2 proceeds to the process of S908, increments the variable C, and S
Proceed to 909. Here, since the processing has not been completed for all closed regions, the answer is NO and the process returns to the overlap determination routine of S905.

[0043] Similarly, the closed area P3 and the closed area P4 are
...The processes of S905 to S909 are repeated in the order of closed region P7. Since all of the closed regions P3 to P7 overlap the closed region P1, overlap flags are set for each of the closed regions P3 to P7, and the thread tension data for each of the closed regions P3 to P7 is changed and set. This result is shown in the memory map shown in FIG.

[0044] When the processing is completed for all closed regions, the determination result in S909 becomes YES, and the CPU 72
Proceeding to the process 910, each closed region is automatically divided into a plurality of blocks and block data is calculated based on the contour data of the closed region whose thread tension has been changed and the contour data of the closed region whose thread tension has not been changed. . When calculating this block data, the sewing order when embroidering a closed area is also calculated for each block. The automatic calculation from contour data to block data and the calculation of the sewing order of blocks are described in Japanese Patent Application No. 1-279381 filed by the present applicant, so a detailed explanation thereof will be omitted. Furthermore, the CPU 72 is
Proceeding to step 911, needle drop position data indicating the needle drop position when embroidering the block is calculated based on the block data and thread density data. This calculation is performed using the well-known method shown in FIGS. 11 and 12.

After that, the CPU 72 stores the needle drop position data in the RAM 76 in the sewing order, and also stores thread tension data corresponding to each piece of needle drop position data and synthesizes it with the embroidery sewing data (S912). The process is completed by storing the data in a storage medium such as a floppy disk. That is, as shown in FIG. 8, the thread tension data is a code indicating the initially set tension of the upper thread and lower thread from the start of sewing to the end of sewing in closed region P1, and in the closed region P2.
From the start of sewing to the end of sewing closed area P7, the upper thread tension is a code that is half the initial setting value, and the bobbin thread tension is a code that is twice the initial setting value. .

After the embroidery stitch data has been created as described above, when the operator issues a command from the keyboard 82 to sew the pattern P0 on the embroidery sewing machine, the CPU 72 saves the embroidery stitch data from a storage medium such as a floppy disk. The upper thread tension device 200 reads out thread tension data for each stitch and drives and controls the X-axis feed motor 58 and Y-axis feed motor 64 to move the embroidery frame 42 in the XY direction. The upper thread tension pulse motor 122 is rotated based on the corrected or uncorrected upper thread tension value, and the current supplied to the excitation coil 120 is changed based on the corrected or uncorrected lower thread tension value. Embroidery stitches are performed by changing the tension balance of the lower thread and the lower thread.

Therefore, compared to the tension of the needle thread and bobbin thread when embroidering the closed area P1, the tension of the needle thread when embroidering the closed areas P2 to P7 is halved and the tension of the bobbin thread is twice the tension when embroidering the closed area P1. Therefore, when embroidering the closed areas P2 to P7 (overlapping stitches), the knot of the needle thread and bobbin thread does not come out on the front side of the work cloth.

As is clear from the above description, in this embodiment, the overlap determination routine of S905 and the processing of S906 of the CPU 72 constitute the determining means of the present invention, and
07 constitutes a setting means.

According to this embodiment, the overlapping situation is checked for each closed area, and if there is overlap, the thread tension of the part to be sewn later is changed according to the overlapping situation, so that the bobbin thread is tightened when overlapping sewing is performed. It is possible to prevent the node points from appearing on the front side of the processed cloth. As a result, it is possible to create embroidery sewing data that can be sewn with good appearance even if there are overlapping parts.

Furthermore, in the above embodiment, it is only determined whether or not there is an overlap of closed regions, but if there is an overlap, it is also possible to check how many times there is an overlap and reflect the number of times in the thread tension correction. good.

In addition, in the above embodiment, the tension balance between the upper thread and lower thread is automatically changed when overlapping stitches are performed, but instead of automatically changing the tension balance between the upper and lower threads, it is not necessary to automatically change the tension balance between the upper and lower threads when overlapping stitches are performed. may be displayed in an easy-to-understand manner on the display to allow the operator to manually correct the upper thread tension value and the lower thread tension value directly, or to specify parameters for correction.

In the above embodiment, the final embroidery stitch data (including thread tension data) is stored in the needle drop position data format.
, but it is also possible to output embroidery stitch data in block data format. In this case, when actually sewing embroidery, needle drop position data indicating the needle drop position may be automatically calculated based on block data and thread density data on the embroidery sewing machine side.

Furthermore, in the above embodiment, it was determined whether or not the thread tension balance should be corrected based solely on whether or not the closed areas overlapped, but if the closed area (base area) to be overlapped is satin stitched. In some cases, the fabric to be processed will not be as stiff as when sewing with fill stitches, so the thread tension may be corrected by taking into consideration whether the underlying area is satin stitch or fill stitch, and even with the same fill stitch, the needle drop pitch may be smaller. If this happens, the work cloth will become stiffer, so yarn tension correction may be performed in multiple stages for each of the upper and lower yarns depending on the pitch.

In the above embodiment, the thread tension was corrected for each closed area, but even if the base area is sewn again, if the stitch pitch is long, the bobbin thread is relatively difficult to come out. The thread tension may be corrected for each stitch or each block.

[0055] In the above embodiment, the hardness of the work cloth and the thickness and quality of the threads are not considered, but in addition to the overlap of the closed areas, the hardness of the work cloth and the thickness and quality of the threads are also taken into account. The thread density during sewing may be changed.

In addition, the present invention can be implemented with various modifications and improvements based on the knowledge of those skilled in the art without departing from the scope of the claims.

[0057]

[Effect of the invention] As is clear from the detailed description above,
In the data processing device for a sewing machine according to claim 1, the storage means stores sewing data related to a needle position or area data indicating a sewing area, and the determining means stores the sewing data stored in the storage means. Alternatively, the setting means determines whether or not there is an overlap stitch in which a predetermined area (base area) is filled with stitches and then sews the area again based on the area data, and the setting means determines whether or not there is an overlap stitch in which the area is sewn again after filling a predetermined area (base area) with stitches, When there is stitching, the tension balance between the needle thread and bobbin thread is set so that the needle thread tension is relatively weaker when overlapping the stitches, so the overlap of closed areas ( If overlapping stitches) are detected, the needle thread tension is automatically set to be weaker than the bobbin thread tension, so that the knotting point of the upper thread and bobbin thread does not appear on the front side of the workpiece fabric when overlapping stitches are performed. This allows for good-looking sewing.

Further, in the overlapping sewing method for a sewing machine according to claim 2, the needle that is moved up and down and the work cloth holding means that holds the work cloth are moved relative to each other based on sewing data related to the needle position. Then, when forming a stitch in that area again after filling a predetermined area in the work cloth with a lockstitch stitch consisting of an upper thread and a lower thread, the upper thread and lower thread are used when filling the area with a stitch. The goal is to change the thread tension balance so that the needle thread tension is relatively weaker. It is possible to avoid the inconvenience that the knotting point of the upper thread and lower thread appears on the front side of the workpiece cloth during sewing.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a schematic configuration of a first invention.

FIG. 2 is a configuration diagram of a data creation machine according to an embodiment.

FIG. 3 is a front view showing only the upper thread tension device.

FIG. 4 is a cross-sectional view showing only the essential parts of a horizontal full-rotation hook equipped with a bobbin thread tension device.

FIG. 5 is a block diagram showing the electrical configuration.

FIG. 6 is an explanatory diagram showing the contents stored in the storage means.

FIG. 7 is an explanatory diagram showing a pattern P0 to be embroidered.

FIG. 8 is a table showing the yarn tension for each closed area before and after the treatment in this example.

FIG. 9 is a flowchart showing the overall flow of processing in this embodiment.

FIG. 10 is a flowchart showing the processing flow of an overlap determination routine in this embodiment.

FIG. 11(a) is an explanatory diagram showing a rectangular block. (b) is an explanatory diagram showing an actual needle drop position calculated based on block data of a rectangular block.

FIG. 12(a) is an explanatory diagram showing a triangular block. (b) is an explanatory diagram showing the actual needle drop position calculated based on the block data of the triangular block.

[Explanation of symbols]

24 Needle 42 Embroidery frame 58 X-axis feed motor 64 Y-axis feed motor 70 Control device 72 CPU (Central Processing Unit) 74
ROM (read only memory) 76
RAM (random access memory) 78
Bus 80 Input interface 82
Keyboard 84 External storage device 120 Excitation coil (lower thread tension device) 122
Upper thread tension pulse motor 200
Upper thread tension device 300 Horizontal full rotation hook PO Patterns P1 to P7 Closed area

Claims (2)

[Claims] 1. A needle that is moved up and down, work cloth holding means for holding work cloth, storage means for storing sewing data or area data indicating a sewing area, and sewing data or area read from the storage means. A drive means that generates relative movement between the needle and the work cloth holding means in a direction intersecting the vertical movement axis of the needle based on the data, and a tension balance between the upper thread and the bobbin thread is changed based on the thread tension data. The data processing device for a sewing machine is equipped with a thread tension changing means that performs overlapping stitching, in which a predetermined area is filled with stitches based on the sewing data or area data, and then the area is sewn again. If there is overlapping stitching, the thread tension data is adjusted so that the tension balance between the needle thread and bobbin thread is determined so that the needle thread tension is relatively weaker. A data processing device for a sewing machine, comprising a setting means for changing settings. 2. A needle that is moved up and down and a work cloth holding means that holds the work cloth are moved relative to each other based on sewing data related to the needle position, so that the work cloth is freed from the upper thread and the bobbin thread. This is a sewing machine overlapping method in which a predetermined area is filled with a lockstitch stitch and then a stitch is formed in that area again, and the tension balance between the upper thread and lower thread when filling the area with the stitch is
This method of overlapping stitching for a sewing machine is characterized in that the tension balance is varied when the area is once filled with stitches and then the stitches are formed again, so that needle thread tension is relatively weaker.