CZ20023369A3 - Stitch forming method and device - Google Patents

Description

Method and apparatus for making a stitch

Technical field

BACKGROUND OF THE INVENTION The present invention relates to a method and apparatus for making a stitch in a sewing machine, and more particularly to a method and apparatus for making a stitch on a sewn material, such as fabric or leather, for use in motor vehicle seats, furniture or the like. the suture material is aligned and their distal ends are sewn together so that the suture material is divided to open for use with the suture portion that is on its inner side.

BACKGROUND OF THE INVENTION

When the above-mentioned sewing is normally performed using a sewing machine, as shown, for example, in FIG. 7, the upper sides of the upper fabric W1 and the lower fabric W2 are first aligned, after which the lateral edge portions of the upper and lower fabric are sewn together by means of a blocking stitch by means of the upper thread NS and the lower thread US, as shown in FIG. 8, by the mutual cooperation of the needle and the hook.

• ·

Then, as shown in FIG. 9, the top fabric W1 and the bottom fabric W2 are brought into a state where they are split apart for use by inserting the stitched end portions on the inner side.

However, as shown in Figures 7 and 8, the strength of the fastening force on the sewing portion is determined by the respective tensile strengths of the upper thread NS and the lower thread US, the frictional forces of the upper thread NS and the lower thread US and their knot. and a frictional force generated between the upper thread NS and the lower thread US extending over the upper and back sides of the upper fabric W1 and the lower fabric W2, and the upper fabric W1 and the lower fabric W2. Thus, the intensity of the fastening force on any sewing portions depends on one piece of thread.

When the sewing portion is split for opening, the upper thread NS and the lower thread US are elongated, the upper thread knot NS and the lower thread US are deformed, and the upper fabric W1 the lower fabric W2 is compressed in portions contacting the upper thread NS and the lower thread US with a top fabric W1 and a bottom fabric W2.

Thus, when the sewing portion is split for opening, the contact surfaces of the upper fabric W1 and the lower fabric W2 in the knot are on the outside, and as shown in Figure 9 there is a problem that the upper thread NS, lower thread US or knot both of these threads appear on the upper sides of the upper fabric W1 and the lower fabric W2, which leads to a deterioration in the commercial value.

Further, in order to strengthen the knot force through the upper thread NS and the lower thread US, it is advantageous to increase the sizes of the upper thread NS and the lower thread US and to increase the tension of the upper thread NS and the lower thread US.

However, in the lockstitch machine, the knot is formed in the central portions of the upper fabric and the lower fabric by balancing the tension of the upper thread NS and the lower thread US, the means for applying tension to the lower thread US arranged in the bobbin housing. thus, there is a design constraint in increasing the tension of the lower thread US, so that high stresses on the upper thread NS and the lower thread US cannot be achieved, and there is a restriction in terms of strengthening the knot force with the upper thread NS and the lower thread US.

Although the fabrics are stitched together at the anticipated increase in tension as described above, there is a problem that, upon impact, the portion divided to open the sewing portion as shown in FIG. 9 and the upper thread NS, the lower thread The US or knot of both of these yarns appear on the upper sides of the upper fabric W1 and the lower fabric W2, thereby deteriorating the commercial value.

Although the fastening force is increased by the chain stitch in combination with a plurality of threads, such as a double chain stitch or a cover chain stitch, when the chain stitch is partially cut off, the chain stitch is frayed on the cut portion, resulting durability problem.

• • •

Although it is advantageous to increase the strength of the fastening force by re-stitching a conventional stitch that has been stitched together to cover the stitch thread, in this case the upper fabric and the lower fabric must be returned to the sewing start position and stitched again, causing the problem of to reduce operating efficiency, while it is difficult to stab the needle into the same part of the stitch that was sewn together before, so that the deformation of the knot of the upper thread NS and the lower thread US cannot be prevented.

Although it is preferable to sew the upper fabric W1 and the lower fabric W2 together with two pieces of threads HS1 and HS2 by hand stitching, as shown in Figure 10, there is a problem that stitching takes too much time, deteriorating sewing efficiency, whereby a long stitch cannot be produced because the length of the thread is limited.

SUMMARY OF THE INVENTION

In order to solve the above-described problems of the prior art, in accordance with the present invention, a method of stitching a sewing machine has been developed for continuously performing stitches on a fabric by repeatedly forming a plurality of stitches by means of a fabric feeding device, and then forming the stitches by feeding the fabric on the stitches in a direction opposite to the first direction by the same size of fabric feeding with the aid of a sewing machine to form a lock stitch.

• ·

In accordance with the present invention, the upper fabric and the lower fabric, which are sewn together using a blocking stitch to hold the thread in each stitch, are provided with a plurality of knots at the respective stitching points, and then the respective tensile stresses of the upper thread NS and the lower thread US is increased, and the friction force in the knot of the upper thread NS and the lower thread US at the respective stitching points is also increased.

Since a plurality of pieces of the upper thread NS and the lower thread US pass over the upper and end sides of the upper fabric W1 and the lower fabric W2, a high frictional force is therefore generated between the upper thread NS and the lower thread US and the upper fabric W1 and the lower fabric W2 .

the strength of the fastening force is further distributed into a plurality of yarn pieces.

In accordance with the embodiment described above, if it is. the sewing portion is split to open, so that the extensions of the upper thread NS and the lower thread US are shortened, the knot deformation of the upper thread NS and the lower thread US is also reduced, and the compression of the upper fabric W1 and the lower fabric W2 in NS and the lower threads US and the upper fabric W1 and the lower fabric W2.

As a result, it is prevented that the contact surfaces of the suture portion of the upper fabric W1 and the lower fabric W2 are allowed to open when the suture portion is divided for opening.

In addition, even if the part of the sewing section that is divided for opening is subjected to impact, the upper • · · *

the yarn NS, the lower yarn US, or the knot of some of these yarns does not appear on the upper sides of the upper fabric W1 and the lower fabric W2, resulting in excellent impact resistance, so that the commercial value of the resulting product is increased.

Furthermore, even if the yarn is partially cut in the stitch, since the stitch is a blocking stitch, the yarn is not frayed from the sewn part, resulting in an excellent durability effect.

According to the present sewing method, the fabric can be sewn continuously, thereby achieving the effect of increasing the operating efficiency of the sewing.

In addition, the needle may be stitched in the same part as the previous stitched stitch, so that the knot deformation of the upper thread NS and the lower thread US can be prevented so that the effect of improving the quality of the final product as well as the commercial value of the stitched product.

Accordingly, the present invention provides a method of forming a stitch in which a stitch is formed continuously on the fabric by repeating the stitching of the fabric together with two stitches in one direction, and then stitching the fabric together with one stitch in a direction opposite to the first direction.

The present invention can reliably achieve the above effects.

The present invention also provides a method of forming a stitch in a sewing machine for continuously forming the stitch on

• ·

fabric by repeatedly stitching the fabric by feeding the fabric by 2n stitches in one direction to the sewing machine to create a lock stitch using the fabric feed device, and then forming the stitch by feeding the fabric on the stitches in the opposite direction to the first direction by the same size .

In accordance with this invention, similar effects to those described above are achieved.

The invention also relates to a method of stitching a sewing machine as described above, in which at least one or more of the stitches are formed on the respective sewing portion.

In accordance with this aspect of the invention, a stitch having a strong knot force is provided at the respective location of the sewn parts, thereby further enhancing the effects described above.

The invention also relates to a sewing machine with a sewing machine with a lockstitch machine, wherein there is a device for feeding the fabric in one direction as well as in the opposite direction to the first direction, and also control means for continuous control. a fabric feeder to feed the fabric of the (n + 1) stitches in one direction and then feed the fabric using the fabric stitcher in the opposite direction to the first direction for the same feed size.

• ·· «

• · · ·

In accordance with this aspect of the invention, similar effects to those described above are achieved.

Accordingly, in accordance with the present invention, a method of forming a sewing machine stitch has been developed, wherein stitches are continuously formed on fabrics by repeating the step such that a plurality of stitches are produced by feeding fabrics of (n + 1) stitches in one direction to the sewing machine. the fabric feeder, whereupon stitches are then formed by feeding the fabrics upstream of (n) stitches in the direction opposite to the first direction by the same amount of feed.

In accordance with a preferred embodiment of the present invention, the stitches are continuously formed on the fabrics by repeating the step such that a plurality of stitches are produced by feeding the fabrics two stitches in one direction to the sewing machine using the fabric feeder. feeding the fabrics upstream by a single stitch in a direction opposite to the first direction by the same amount of feed.

In accordance with another preferred embodiment of the present invention, the stitches are continuously formed on fabrics by repeating the step such that a plurality of stitches are produced by feeding fabrics of (2n) stitches in one direction to the sewing machine using the fabric feeder. stitches by feeding fabrics upside down (n) stitches in a direction opposite to the first direction by the same feed size.

• · • ·

Preferably, at least one or more attachment stitches are formed as the respective sewing point.

In accordance with another aspect of the present invention, a stitching machine for a sewing machine comprising:

a sewing machine for forming a lock stitch, a fabric feeding device for feeding the fabric in one direction and in a direction opposite to the first direction, and control means for continuously controlling the fabric feeding device to advance the fabric feeding device by (n + 1) stitches in one direction, and then to move the fabric feeding device upside down by (n) stitches in the direction opposite to the first direction by the same amount of feed.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained in more detail by way of examples of specific embodiments thereof, the description of which will be given with reference to the accompanying drawings, in which:

Fig. 1 shows a block diagram of a control circuit according to the present invention;

Fig. 2 shows a schematic illustration of a fabric feeding mechanism of a sewing machine as an exemplary embodiment of the fabric feeding device of the present invention;

Fig. 3 is schematic views of respective, showing respective states of the fabric feeding mechanism of Fig. 2, wherein Fig. 3A illustrates a zero feed condition; Fig. 3B illustrates a positive feed condition; and Fig. 3C illustrates a reverse feed condition; Fig. 4 shows a stitch made in accordance with a first embodiment of the present invention;

Fig. 5 is a perspective view of a split state for opening a sewing portion of a stitched fabric with the aid of a stitch according to the present invention;

Fig. 6 is a flow chart of an embodiment of the present invention;

Figure 7 is a perspective view of a conventional stitch;

Fig. 8 is a cross-sectional view taken along the line V-V of Fig. 6;

Fig. 9 is a perspective view of the split state for opening the sewn product of Fig. 7 from the sewing portion;

Fig. 10 is a cross-sectional view of another commonly known stitch.

··· «···

DETAILED DESCRIPTION OF THE INVENTION

The first embodiment of the present invention will now be explained with reference to the Figures 1 to 6.

The fabric feeding apparatus 29 shown in Figure 2 has a similar configuration to the fabric feeding mechanism of a conventional sewing machine. Reference numeral 2 denotes the main shaft of the sewing machine and reference numeral 10 denotes the eccentric cam arranged on the main shaft 9.

Reference numeral 11 denotes a fabric feed quantity changer, the central portion of which is rotatably mounted at the lower part of the sewing machine (not shown), on the shaft 12. At the left end of the fabric feed changer 11, the lower portions of the two connecting members 13 and 14 having the same length and being mounted on coaxial shafts 13A and 14A, the front ends of the links 13 and 14 being connected by a common shaft 15. The feed control mechanism is formed by the fabric supply changer 11, the links 13 and 14 and the shaft 12 and 15.

Reference numeral 16 denotes a direct drive motor attached to a sewing machine frame, not shown, wherein the actuator 17 of the direct drive motor 16 and the right end of the fabric load changer 11 are rotatably connected by a link 18.

Reference numeral 19 denotes a vertical coupling member whose upper end is connected to an eccentric cam, its lower end being pivotally connected to a common shaft 15 at the front ends of the coupling members 13 and 14.

Reference numeral 20 denotes a horizontal feed shaft rotatably mounted at the bottom of a sewing machine, not shown, the right end of the horizontal feed shaft 20 being attached to the lower end of the arm 21 extending upward, the left end attached to the lower end of the arm 22, projecting upward.

Reference numeral 23 denotes a link 23 whose one end is pivotally connected to a common shaft 15 at the front ends of the links 13 and 14, while its other end is pivotally connected to the front end of the arm 21.

Reference numeral 24 denotes a fabric feed arm, one end of which is pivotally connected to the front end of the arm 22, with the fork portion 25 at its other end loosely attached to a vertical cam 27 arranged on a vertically movable shaft.

Reference numeral 28 denotes a fabric feeder 28 attached to the fabric feeding arm 24.

In accordance with the fabric feeding device 29, when the main shaft 9 rotates as a result of driving the sewing machine, the vertical link 19 moves in a vertical direction due to the action of the eccentric cam 10 so that the common shaft 15 is attached to the lower end of the vertical link. • of Article 19, moves vertically by a constant size.

The vertical movement of the common shaft 15 is transmitted to the horizontal feed shaft 20, as a result of which the fabric feeder 28 performs the feed movement.

That is, in the case where the shafts 13A and 14A are located on the line H connecting the upper end of the arm 21 and the common shaft 15 (see Fig. 3A), if the common shaft 15 is moved vertically by the action of the vertical coupling 19, Although the links 13 and 14 rotate centrally on the shafts 13A and 14A, since the upper end of the arm 21 does not move horizontally, the fabric feeder 28 is stationary, and as a result, the fabric is not fed.

Furthermore, in the case where the shafts 13A and 14A are located on the upper side of the straight line H connecting the upper end of the arm 21 a. The common shaft 15 (see FIG. 3B) when the common shaft 15 moves vertically by the vertical coupling 19, thus, since the links 13 and 14 rotate centrally on shafts 13A and 14A, the common shaft 15 attached to the front ends of the links 13 and 14 describes a rotating geometric location as shown in Figure 3B, resulting in displacement in the horizontal direction at the upper end of the arm 21 so that the fabric feeder 28 performs the movement of the fabric feeding in the correct feeding direction in a state that protrudes from the upper face of the needle opening (not shown).

• ·

Since the positions of the shafts 13A and 14A are separated upwardly from the line H connecting the upper end of the arm 21 and the common shaft 15, the displacement of the arm 21 in the horizontal direction is increased, which also increases the fabric feed size by the fabric feeder 28 in the correct feed direction. .

If the shafts 13A and 14A are located on the underside of the straight line H connecting the upper end of the arm 21 and the common shaft 15 (see FIG. 3C), if the shaft 15 moves vertically through the action of the vertical link 19, 13 and 14 rotate centrally on the shafts -13A and 14A, the common shaft 15 describes a rotating geometric location as shown in FIG. 3C, so that the displacement in the horizontal direction has an inverted phase than in FIG. 3B, this displacement occurs at the upper end of the arm 21, such that the fabric feeder 28 exerts a movement when the fabric is fed in the opposite direction when it projects from the upper face of the needle opening (not shown).

Since the positions of the shafts 13A and 14A are separated downwardly from the line H connecting the upper end of the arm 21 and the common shaft 15, the amount of fabric feeding in the opposite feeding direction is increased.

In this way, the directions of fabric feed and the amount of fabric feed in the right direction and in the opposite direction are determined by the positions of the shafts 13A and 14A, wherein the positions of the shafts 13A and 14A at the front ends of the links 13 and 14 are controlled by a direct drive motor 16.

That is, if the actuator 17 of the direct drive motor 16 positions the lower end of the link 18 such that the positions of the shafts 13A and 14A become intermediate positions, like this position of the straight line H (middle position), the feed rate is zero as above described.

When the actuator 17 of the direct drive motor 16 is lowered to the lower position of the lower end of the link 18 relative to the center position, the fabric load changer 11 rotates clockwise centrally on the shaft 12, with the positions of the shafts 13A and 14A positioned. on the upper side of line H, they are determined by the lowered position of the actuator 17 of the direct drive motor 16, as a result of which the usual feed direction and feed size are determined.

When the actuator 17 of the direct drive motor 16 lifts the lower end position of the link 18 relative to the center position, the fabric supply changer 11 rotates counterclockwise centrally on the shaft 12.

The positions of the shafts 13A and 14A located downstream of the line H are thus determined, the positions of the shafts 13A and 14A being thus determined, the opposite feed direction and the feed amount being determined by the elevated position of the actuator 17 of the direct drive motor 16.

In other words, the direction of fabric feed and the amount of fabric to be fed are determined by • ····

Λ ⁶

the vertical direction of position of the actuator 17 of the direct drive motor 16 by driving the direct drive motor 16.

FIG. 1 is a block diagram of a control circuit as control means according to the present invention, wherein the start / stop button arranged on the foot press pedal is provided to give a start signal when the foot press pedal is pressed by the toe; and for outputting a stop signal by returning the foot-operated pedal to its original position.

The reference numeral 2 denotes a needle position detection device arranged on the main shaft of the sewing machine for outputting a needle position signal by detecting the vertical position of the needle, at least the lower needle position signal being input to the control means 3 consisting of ROM. Direct RAM memories with a CPU base processor, and calculating a down position signal via an internal counter (not shown) of the CPU base processor.

The means for detecting the number of needle drops is formed by a needle detecting means 2 and an internal counter.

Control programs 3 are stored in the non-volatile ROM of control means 3, comprising a correlation between the number of needle drop (n + 1) for conventional feed and the number of needle drop (n) for re-feed, which will be explained later, later, it contains data regarding the normal and reverse feed size and the amount of operation of the direct drive motor 16 (position),

While providing control instructions to ensure the size of the usual and backfeed of the fabric by adjusting the input means 8 with the aid of basic CPU units.

Reference numeral 5 denotes a sewing machine motor for driving or stopping the sewing machine, reference numeral 6 denotes an excitation circuit for driving or stopping the sewing machine motor 5, reference numeral 6 denotes an excitation circuit for driving or stopping the direct drive motor 16, 7, a control circuit for controlling the excitation circuit 5 is indicated so that the operating position of the direct drive motor 16 becomes the position according to the instructions of the control means 3.

Reference numeral 8 denotes the input means for indicating the stitching system for adjusting the number of needle drops (n) for re-feeding or for the usual direction of the amount administered by the operator by means of input to the control means 3.

Optionally, the number of needle sags in conventional administration and the number of needle sags in re-administration can be individually set.

In addition, the pattern, preset for the number of needle drops during conventional feeding and for the number of needle drops upon re-feeding, can be stored in the non-volatile ROM of the control means 3 and optionally adjusted.

The operation of the first embodiment of the present invention will now be explained.

The first embodiment is an exemplary embodiment wherein the needle drops down (n + 1) times in the conventional feed direction, the needle drops down (n) times in the reverse feed direction.

F

In addition, the first embodiment relates to the case where n = 1.

First, η = 1 is entered as the number of needle sinks by the input means 8 using the subroutine input setting (S-1).

Further, the direct drive motor 16 is driven via the drive circuit 6 by instructions from the control circuit 7 to produce a drive size that corresponds to the size of the conventional feed set into the inlet (S-2). As a result, the actuator 17 of the direct drive motor 16 is lowered and set to a predetermined feed rate in the conventional direction.

If the foot pedal is further depressed and a start signal is given by the pushbutton 7 (S-3), the sewing machine motor 5 is driven by the drive circuit 4 (S-4), whereby the sewing machine for stitching is started.

The needle position signal from the needle position detection device 2 is calculated by a counter inside the control means 3, and if no stop signal is given by releasing the pedal (S - 5), the needle drops down a second time and n ₀ = η + 1 is calculated.

That is, the actuator 17 of the direct drive motor 16 is held in the lowered position until the fabric is fed in the usual direction after stopping the needle for the first time and the needle is subsequently lowered (S-6).

The direct drive motor 16 is driven by the drive circuit 6 based on the instructions from the control circuit 7 to produce a drive size that corresponds to the feed rate set then into the input (S-7). Thus, the actuator 17 of the direct drive motor 16 is raised upward to adjust the reverse feed direction by a feed size that is the same as in the conventional feed direction.

When the counter is calculated by no = 1 through the following signal from the needle detecting device 2 (S-8), the direct drive motor 16 is driven to produce a set amount of conventional feed (S-9). Before the stop signal (S-5) is further entered, the operation of setting the conventional fabric feed direction during the needle drop interval is repeated twice, and the fabric feed direction is reversed at the next needle drop.

In other words, the fabric feeding operation is repeated in the usual direction continuously during the needle drop interval twice, and then the fabric feeding operation in the opposite direction is the same amount of fabric feeding as in the conventional feeding direction, and the needle dropping once, created a double stitch.

Next, the state of actual stitching will be explained with reference to the figure of FIG. 4.

• ·

Since in the stitch shown in FIG. 4, the upper threads NS1, NS2 and NS3 and the lower threads US1, US2 and US3 are separated upwards and downwards from the upper surface and the lower surface of the upper fabric W1 and the lower fabric W2, the thread is strongly attached to each stitch and therefore the upper threads and the lower threads are strongly brought into close contact with the upper surface and the lower surface of the upper fabric W1 and the lower fabric W2.

The direct drive motor 16 is driven to a lowered position in accordance with the feed size P in the conventional direction. When the sewing machine motor 5 is driven, the needle is first lowered to the stitch point A in FIG. 4 to form a perfect stitch knot 1A, then the upper fabric W1 and the lower fabric W2 are fed in the conventional feed direction indicated by the fabric direction arrow X By the magnitude P of the feed, the needle drops down to the stitch point B to form the perfect stitch knot 2A.

The above number of needle sinks twice is counted by a counter (no = n + 1), where n is set to n = 1 'and hence n ₀ = 2, the signal is emitted from the control circuit Ί_ based on the control means 3, triggering device. 17 of the direct drive motor 16 is positioned in the raised position in relation to the feed direction P in the opposite direction, which is the same as in the conventional direction, the upper fabric W1 and the lower fabric W2 being fed by the feed size P in the reverse feed direction indicated by the arrow Y of the fabric feed direction, wherein the needle is lowered to the stitch point A and forms a knot 3A of the stitch.

If the number of needle sinks is n ₀ =. 1, calculated at the stitch point A after re-feeding, the actuator 17 of the direct drive motor 16 is positioned in a lowered position which is

the same as in the initial time, the size P of the fabric feed in the conventional direction is set, the upper fabric W1 and the lower fabric W2 are delivered in the size P feed in the conventional direction according to the arrow X of the fabric feed direction, the needle is lowered at the stitch point B for the fourth time the perfect stitch knot 4A is formed.

Further, the top fabric W1 and the bottom fabric W2 are fed in the size P of feeding in the conventional direction, wherein the needle drops down at the stitch point C for the fifth time and the perfect stitch knot 5A is formed.

When the number of needle sinks is twice counted in the usual direction by a counter, the actuator 17 of the direct drive motor 16 is positioned in the up position, similar to the previous time, to set up feed back, the top fabric W1 and the bottom fabric W2 being fed in size. P feeding in the opposite direction according to the arrow Y of the fabric feeding direction, the needle drops down at the stitching point B for the sixth time and the knot 6A of the stitch is formed.

Thus, in view of the stitch formed, as shown by stitch point B and stitch point -C in Figure 4, two perfect stitches and one attachment stitch having a strong knot force are formed at a single stitch point (same needle drop position).

Further, at a one-pitch stitch interval, there are respectively three upper threads NS1, NS2 and NS3 and lower threads US1, US2 and US3 respectively to increase the frictional force at the contact surfaces of the upper thread and the upper fabric W1 and the lower thread and the lower fabric W2.

Even if the stitch portion is split and can be opened as shown in FIG. 5, the suture contact areas of the upper fabric W1 and the lower fabric W2 are not opened as the upper fabric W1 and the lower fabric W2 are stitched to with the help of such a stitch.

Although the initial re-immigration is not performed in the above-described first embodiment of the present invention, the initial re-immigration may be performed based on the operating signal issued by the operator.

For example, when rewinding at the beginning of sewing after feeding the fabric in the opposite direction (X direction) by the same feed size (pitch), the needle drops down at the stitching point to return stitching, then the fabric is fed in the usual feed direction by the same pitch. The fabric is formed at the stitching point A, the fabric is again fed in the opposite feeding direction by the same pitch and the stitch is formed at the aforementioned re-immigration point.

Further, upon completion of the initial re-immigration, a stitch is formed in the first embodiment.

Furthermore, the re-immigration can also be carried out at the end of the sewing.

In addition, the initial return and final return can be automatically performed with the start signal and the end signal of the foot presser pedal if the signal input to the sewing machine control is set, for example, via a foot switch.

The number of needle sinks (number of sutures) to form a stitch during conventional administration, and the number of needle sinks (number of sutures) to produce a stitch on back feed, as shown in the above-described embodiment, can be varied as desired. For example, after performing a needle drop four times in conventional administration, a needle drop may be performed twice in reverse administration. As a result, when the needle is dropped a third time and thereafter, two perfect stitches and one attachment stitch are formed at the respective point of the needle drop.

Although, in the above-described exemplary embodiment, the situation where the number of needle sinks for a. the stitching of the fabric together by conventional feeding is greater than the number of sags of the needle for sewing the fabric together by means of the back feed, in contrast, the number of sagging needle when sewing the fabric together by means of back feed can be greater administration.

Although in the present sewing machine, there is a case where, even if the same feed size is set for conventional feed and back feed, the actual feed size varies slightly depending on the shape of the feed, with essentially the same needle drop point and substantially the same drop point of the needle may remain the same.

Although, in the embodiment described above, the state of feeding the top fabric and the bottom fabric through the fabric feed mechanism of the sewing machine as the fabric feed device has been explained, the fabric feed device has been explained.

it can be replaced by the well-known feeding device X-Y.

As a result, not only a straight stitch, but also a stitch of any shape, such as a curve stitch or a stitch in which the curve and the line are continuous, can be produced.

Regarding the knot of the upper thread NS and the lower thread US at the respective point of sewing the fabric, the stitch can be arbitrarily formed by controlling the upper thread NS, the lower thread US or the needle.

In the case where there is no need to make the stitch, it is also possible to prevent the stitch from being formed at the appropriate stitching point of the fabric by employing a generally known stitch prevention mechanism, e.g. of the stitch by rotating the needle bar and the hook in the axial direction.

Industrial applicability

As described above, in accordance with the present invention, a plurality of knots are formed at the respective needle drop point (the stitching point together) as a result of the upper fabric and the lower fabric sewn together with the blocking stitch when fastening the thread at each stitch. thereby increasing the tensile strength of the upper thread NS and the lower thread US, and further increasing the frictional force of the upper thread NS and the lower thread US in the knot at the respective stitching point together.

In addition, a plurality of pieces of the upper thread NS and the lower thread US pass over the upper and back sides of the upper fabric W1 and the lower fabric W2, resulting in a high frictional force between the upper thread NS and the lower thread US and between the upper fabric W1 and the lower fabric W2.

The intensity of the fastening force is thus dispersed into a plurality of thread pieces.

From the above. it follows that if the sewing portion is split for opening, the extensions of the upper thread NS and the lower thread US are reduced, and the deformation of the knot of the upper thread NS and the lower thread US is further reduced. the threads NS and the lower threads US and the upper fabric W1 and the lower fabric W2 are significantly reduced.

Thus, in accordance with the present invention, when the sewing portion is split for opening, the contact surfaces of the upper fabric W1 and the lower fabric W2 are prevented from being opened, the upper thread NS, the lower thread US or the knot of both. the upper side of the upper fabric W1 and the lower fabric W2, which results in the effect of increasing the commercial value of the product, while also achieving excellent impact resistance since the upper thread NS, lower thread US or knot of both threads do not appear on the upper sides of the upper fabric W1 and the underside fabric W2 even if there is an impact on the portion of the distribution to open the sewing portion.

In addition, even if the thread is partially cut in the stitch, since the stitch is a blocking stitch,

there is no fraying of the thread, resulting in an excellent durability effect.

As a result of the sewing method, the fabric can be sewn continuously so that the effect of increasing the operating efficiency of the sewing is achieved.

In addition, the needle may be stitched into the sutured portion at substantially the same location as the previous needle drop point, furthermore deformation of the knot of the upper thread NS and the lower thread US can be prevented resulting in improved product quality and commercial value product.

Furthermore, since the attachment stitch, having a strong knot force, is formed at the respective point of sewing the fabric together, the effect of further enhancing the effects described above is achieved.

Claims (5)

PATENT CLAIMS A method of forming a stitch in a sewing machine, characterized in that stitches are continuously formed on fabrics by repeating the step such that a plurality of stitches are produced by feeding fabrics of (n + 1) stitches in one direction to the sewing machine using feeding the fabric, whereupon stitches are then formed by feeding the fabrics upstream of (n) stitches in a direction opposite to the first direction by the same amount of feed. A method of forming a stitch in a sewing machine, characterized in that stitches are continuously formed on the fabrics by repeating the step such that a plurality of stitches are produced by feeding the fabrics two stitches in one direction to the sewing machine using the fabric feeding device. whereupon stitches are then formed by feeding the fabrics upside down by a single stitch in a direction opposite to the first direction by the same amount of feed. 3. A method of forming a stitch in a sewing machine, characterized in that stitches are continuously formed on fabrics by repeating the step such that a plurality of stitches are produced by feeding fabrics of (2n) stitches in one direction to the sewing machine using the fabric feeder. whereupon stitches are then formed by feeding the fabrics upstream of (n) stitches in a direction opposite to the first direction by the same amount of feed. A method of making stitches in a sewing machine according to any one of claims 1, 2 and 3, characterized in that at least one or more attachment stitches are formed as the respective sewing point. 5. A stitching machine for a sewing machine, comprising: a sewing machine for forming a lock stitch, a fabric feeding device for feeding the fabric in one direction and in a direction opposite to the first direction, and control means for continuously controlling the fabric feeding device to advance the fabric feeding device by (n + 1) stitches in one direction, and then to move the fabric feeding device upstream of (n) stitches in the direction opposite to the first direction by the same amount of feed.