JPS58169491A - Corner stitching method of sewing machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a corner stitching method (C) for making corner stitches appropriate when corner stitching is performed on a midsine forming a wood stitch L1.

Conventionally, for example, the sword was almost synchronized with the lower feed dog to feed the cloth.
In a single-feed lockstitch sewing machine that swings backwards to feed the fabric and forms a lockstitch in cooperation with a horizontal hook, the hook tip captures, for example, a needle thread loop at a corner. 1: Stop the sewing machine at the lowered position of the inter-axis rotation angle (point A in Figure 8) and rotate the fabric at a predetermined angle around the sword at the lower position. However, when the sewing machine is driven again after turning the fabric at the corner, as is clear from Fig. After it comes out, the needle moves forward in the cloth feeding direction together with the first feed dog, and the balance lags behind the first bar and moves to the front in the cloth feeding direction.
Pull the needle thread with L. When the sword reaches the dead center, the feed dog has moved forward with the sword in the cloth feeding direction.For example, in Fig. 10, the copper feed dog is at point Na.
The bobbin thread U moves from the bobbin thread payout portion R of the hook to the point Nd.
-N d- Φ1 in front of the corner - spanning between the falling point Nc,
Therefore, the balance should lift the copper threads T intertwined between the bobbin threads U between N c and N d to υ
, in the horizontal direction (in the direction of arrow a) toward j. The needle thread tension (
Due to the lack of lifting force, the cotton knots remained on the back side of the fabric, resulting in so-called I-knee 1s.

In addition, when forming a corner stitch on a wood stitch sewing machine with two needles, for example, when the left needle is used inside the corner as shown in Fig. 12.18, the inside CD gold 1 is set to the Φ1 falling point N.
bVC, the body is placed in the 10th position f, I- state by well-known means, and the U [continues to form a predetermined number of substitches with only the outer lead sword, and the needle tip C is placed in the fabric at the nail drop point Na. Φ stuck [lower position (point A in Figure 8)] Stop the sewing machine and move the fabric in the opposite direction (centering on the outer edge)
(Fig. 12), drive the sewing machine again, form the outer stitch to the position corresponding to the body of the inner stitch + l = position N' b, and then return the inner hook 1 to the operating state again. I was trying to do the same thing as Niki Kenwai. Also the 14th
．． As shown in Fig. 15, when the gold 1 on the right side is placed on the inside of the corner, similarly, the inner needle is in a resting state at the needle drop point Nf, a stitch is formed with only the outer needle to the needle drop point NO, and the sewing machine is started. Stop at the needle down position +-t-L, turn the fabric clockwise (Fig. 148) by a predetermined angle, form an outer stitch again from the outer side to a position corresponding to the needle drop point Nf, and then insert the inner needle. 111, then returned to the working state and performed double needle stitching.

In the inner corner portions Nb and Nf, while the outer corner stitches are being formed, the bobbin threads Ua and Ub are fed out by a well-known bobbin thread absorption spring (Utility Model Publication No. 11896-Bow of 1982) provided in the hook. While the needle threads T a and Tb are constantly being pulled back to the parts R and L, the needle threads T a and Tb are applied again at the inner corner parts, and the needle thread is pulled back when forming (). I couldn't get over it and made a 1-re'' S.

Jf ], -1 This two-wood single-stitch sewing machine has the above-mentioned Φ
When the sewing machine has the one-feed function, "one-feed" S occurs at the outer corners Na and No for the same reason as explained for the gold one-feed sewing machine.

This invention focuses on the above-mentioned corners [-t'l-1
An embodiment of the present invention will be described with reference to the drawings.

The sewing machine shown in FIG. 1 is a needle-feed lockstitch sewing machine, and has a needle bar 2a in which needles 1a and lb are separately fixed to the lower end and arranged in parallel to the left and right (direction intersecting the cloth feeding direction).

21] is linked to a main shaft (not shown) that rotates in conjunction with a motor M (Fig. 7) that is a drive source, and moves up and down and reciprocates along the cloth feeding direction to feed a lower feed dog (not shown). Although it is not shown in the figure, it is possible to interlock the cloth feed in cooperation with the
A pair of horizontal hooks having a well-known thread absorbing means described in Japanese Patent No. 11896 and the like are arranged below a throat plate (not shown). Further, one of the needle bars 2a and 2b can be brought to rest at a predetermined position corresponding to the needle up position by a well-known needle bar resting mechanism 3. It is controlled by operating the operating lever 4 as described in the specification of Sho 51-60880 and the drawings. When the operating lever 4 is in the intermediate position (Fig. 1), both needles 1a and 1b are activated to perform double-needle sewing, and when it is in one position where it is rotated clockwise, one needle, for example, in Fig. 1, is rotated clockwise. The left needle 1b is put in a resting state, and when the needle is rotated counterclockwise to the other position, the other needle, for example, the right hand needle 1a in FIG. 1, is put in a resting state to perform single-needle stitching. At the rear of the sewing machine, a cam plate 82 is provided on the rotation shaft of the operating lever 40 and has a protrusion 82a formed at the center of the tip.
is fixed, and is rotatably supported on a shaft 88 parallel to the rotation axis of the operating lever 4, and fixed at one end to the sewing machine frame l by means of a winding/flange (not shown) that always moves the left side in Fig. 6. The distal end of the engaging body 34 that receives the force acting on the cam plate 8 is formed into a bifurcated shape, and the inward end surface of the locking portion 84a is bent forward at the negative side ('7).
When the operating lever 4 is in the intermediate position, the inner end surface of the engaging portion 84a is engaged with the protrusion 82a of the cam plate 82 against the acting force of the coil spring. Combine 8
4 is maintained in the rotational position on the right side in FIG. to maintain the rotation position. A permanent magnet 85 is fixed to the upper part of the other side 84b of the two-pronged part of the engaging body 84, and the engaging part 34a engages with the cutout part 82b or 82c of the cam plate 32, facing the permanent magnet 35. A magnetic sensing body 36 that senses the magnetism of the permanent magnet 85 is fixed to the machine frame 1 only when the engaging body 84 rotates to the left in FIG. Further, the electromagnet 3
The tip of the plunger 88 of No. 7 is fixed, and when the electromagnet 870 is activated, the plunger is turned into a suction bow and the engaging body 34 is
? ) The engaging portion 84a is rotated to the right in FIG. 6 until the engaging portion 84a engages with the protrusion 82a of the cam plate 82 against the acting force of the coiled spring.

5 is a needle thread Ta with both needles 1a and lb interlocked with the main shaft.

6 is a well-known thread tension device (main tension device) having tension discs on the same axis to apply thread tension to the needle threads Ta and Tb separately; 7.8 is a main tension device; A pair of well-known thread tension devices are arranged so as to separate the paths of the needle threads Ta' and Tb on the side of the thread supply source from the device 6, and apply thread tension to each of the needle threads 'ra and 'rb.

Although not shown in the drawings, each of the threads has a regulating means (not shown) that engages with the tension disc and clamps the tension disc to make it impossible to unwind the thread. Main tuner 6 and both side tuners? , 8, a long elongated hole 9. is formed on the front end surface of the sewing machine frame opposite to the path of the double-needle threads Ta and Tb, passing through the machine frame and extending in the direction of intersection with the paths of the double-needle threads Ta and Tb. form 10.

Inside the sewing machine frame, a pair of support shafts 18, 14 spaced apart from each other along the opening direction of the elongated hole 9 are fixed to the machine frame, and one thread pulling means 12 related to the needle thread Tb
The action body 15 is provided with long holes 15a and 15b in the direction intersecting with the path of the shafts 13 and 14.
is supported by being loosely fitted so as to be slidable in the longitudinal direction, and protrudes outward from the long hole 9 at the distal end of the machine frame to allow the needle thread Tb to cross over the needle thread Tb. an engaging portion 15cL having a vertical rear end surface (right end surface in FIG. 2) and a restricting portion 15θ that protrudes downward from the lower end surface of the rear end and has a front end surface as a circular arc, and when the tip is operated, the catching portion 15
Before c intersects the needle HT b path, a regulating means that engages with the tension plate of the sub tension device 7 acts, and the coiled spring 16 always acts in the direction in which the thread catching portion 15c is separated from the needle thread Tb. Receive power.

The rotary solenoid 17 has an operating arm 18 on an operating shaft 17a.
The lower end of the operating arm 18 is fixed, and the upper end of the operating arm 18 supports a pin 18a that engages with the rear end surface of the engaging portion 15d of the effecting body 15.
Due to the action of the tally solenoid 17, the effecting body 15 is moved against the winding spring 16 so that the catching portion 15c crosses the path of the IT thread Tb.

The other thread pulling means 19 related to the needle thread Ta is a long hole 20a that is long in the direction intersecting the path of the thread Ta.

20b/: Set the working body 20, and open the elongated hole 20a,
201), the support shaft 18.74 is fitted loosely in the longitudinal direction so as to be slidable in the longitudinal direction, and is supported in parallel with the long hole 20a on the tip side.
A pin 21 is formed in a protruding manner parallel to the support shaft 13 at a distance from the side, and an operating piece 22 whose end is supported on the support shaft 13 rotatably fits the pin 2 into a groove 22a formed at its lower end. The needle thread T
It is assumed that the catching section 22c is capable of crossing over the points a and a. Acting body 20
an engaging portion 20c that protrudes in the -L direction from the upper end surface of the intermediate portion and has a vertical rear end surface (the right end surface in FIG. 8), and a regulating portion 20d that protrudes downward from the lower end surface of the rear end and has a front end surface that is an arc. and an operating part 20e protruding northward from the tip-[second part].
, and when the rotary solenoid 240 (described later) is activated, the trapping part 22c intersects the gold thread Ta path (adverb).
Use the regulating means that engages the plate (4) and always unwinds (2):
As a result, the catching portion 22c receives an acting force in the direction of separating the gold threads Ta and J from each other. The rotary solenoid 24 is activated] The lower end of the operating arm 25 is fixed to the pongee 24a, and the operating arm 25
The upper end supports a pin 25a that engages with the rear end surface of the engaging part 20c of the effecting body 20, and by the action of the rotary solenoid 24, the effecting body 20 is moved against the winding spring 28, and the catching part 22c is attached to the side thread. The action piece 22 is rotated about the pin 21 so as to cross the path of Ta.

Restricting parts of effecting bodies 15, 20]-5e, 2nd, facing each other in front (left side in Figures 2 and 8) and supporting shafts] 3° 14 parallel support shafts 26.2'/ to the machine frame. supported rotatably against the
Support shaft 26, 278;
Adjustment body 28, 29 with a conical cam that can be engaged with 20cl is fixed, and operation knob 3 is provided on the outside of the machine frame.
0 and 81, the adjusting bodies 28 and 29 can be moved forward and backward in the axial direction of the support shafts 26 and 270 respectively.

Next, the electric circuit will be explained.

(/l) NP is a nail position detection means, which detects the spindle rotation angle corresponding to the upper and lower positions of the needle and generates an upper position signal and a lower position signal, and C8 is a needle number setting. This means sets the number of stitches to be performed on the outside side during corner stitching, and generates a setting signal of a different digital code corresponding to the number of settings.

■, SW is a start switch that generates a start signal when the pedal (not shown) is depressed; Ml, 8W are off when the operating lever 4 is in the intermediate position (double-needle state); one or the other position (single-open state); The sewing state detection switch (magnetic sensor 36), which is turned on when

r sw, osw, and wsw are individually arranged on the machine frame so that they can be operated manually, and are used as rotary solenoids during corner sewing.17.
This is a setting switch that specifies the action of 24, and when operated, the ISW generates a -th designated signal to activate the low clean renoid]7 or 24 corresponding to the needle thread of the inner needle. O8W is the rotary lean l/noid 17 or 24 corresponding to the needle thread of the outer needle.
The second designation for causing ``tj to occur, wsw
are rotary solenoids 17 and 2 corresponding to both needle threads.
4. A third designated signal is generated to effect the operation.

NC is a corner stitching control circuit for performing the automatic corner stitching described in the above-mentioned Japanese Patent Application No. 51-60880, and a corner stitching state detection switch M] is closed in connection with generation of an ON signal of SW. Then, the motor M is driven in conjunction with the generation of the start signal of the next start switch LSW, and the number of 1] - Nobuso Iwaka generated from the nail position detection means NP is equal to the set value of the open number setting means C8. When the sewing machine reaches the needle down position, the motor M is stopped at 6, and the next start switch is driven in conjunction with the generation of the SW start signal, and the number of -I- position signals is When the electromagnet Mg 1 (
37), the motor drive circuit MD and the electromagnetic actuation circuit MA1 are controlled so as to activate the motor drive circuit MD and the electromagnetic actuation circuit MA1.

TC], Te3. Te3 is a side thread control circuit, which inputs the outputs of the start switch LSW, the corner stitch control circuit NC2, the sewing state detection switch MISW, and the needle detection switch M2SW, respectively, and the control circuit TCI inputs the respective inputs and setting switch ISW. The circuit is closed by the input of the first specified signal ＼ Sewing state detection switch MISW at the inside corner
The rotary solenoid 17 or 24 corresponding to the needle thread of the idle needle is operated for a certain period of time Δt (the movement of the operating body 15.20) by the signal from the needle detection switch M2SW. The electromagnetic actuating circuit MA2. Controls MA8. Further, the needle thread control circuit TC2 includes the above-mentioned input and setting switches O.
The circuit is closed by the input of the second designated signal of SW, and it acts in connection with the generation of the start signal from the pedal start switch LSW at the outer corner, and corresponds to the needle thread of the working side needle according to the signal from the needle detection switch M2SW. 2. The electromagnetic actuating circuit MA operates one rotary solenoid 17 or 24 for a certain period of time Δt. Control MAB. Further, the control circuit 'I'ca is closed by the input of each input and the third designation signal of the setting switch WSW, and the control circuit 'I'ca is closed in the same way as the control circuit Tel at the outer corner, and the control circuit TC2 at the inner corner. Similarly to the control, the electromagnetic actuation circuit MA
2. Control MAR.

The present invention has the above structure, and its operation will be explained next.

Start stitch formation from the double-needle sewing state with the operating lever 4 in the intermediate position, and turn the sewing machine at a main shaft rotation angle of the needle down position (point A in Figure 8) at a predetermined position Nb in front of the corner of the fabric (not shown). When sewing the left needle 1b as the inner needle as shown in FIGS. 12 and 13, for example, when the operation lever 4 is rotated to one position, the pause mechanism 8 brings the needle bar 2b to the pause state. At the same time, the needle detection switch M2SW is turned on, and the cam plate 32 rotates counterclockwise in FIG. The magnetism of the permanent magnet 85 is detected by the magnetic sensor 86.
is detected, and the sewing state detection switch MISW generates an on signal. Further, the setting (/S) of the stitch number setting means CS is set to 8, and the setting switches psw and osw are set according to the sewing conditions obtained experimentally in advance.

Operate any one of WSW, for example, here WS
A second designation signal is generated by operating W.

In connection with the generation of the second designation signal, the needle thread control circuit TC8 is closed.

When the pedal is depressed in this state and a start signal is generated from the start switch LSW, the motor M is driven via the motor drive circuit MD under the control of the corner stitch control circuit NC, and a stitch is formed only by the outer needle 1a. In connection with the generation of the third stitch upper position signal from the position detection means NP, the motor M is stopped so as to stop the main shaft of the sewing machine at the rotation angle of point A in FIG. The operator pulls up the presser foot 89 above the throat plate, and turns the cloth at a predetermined angle counterclockwise (FIG. 12) around the outer needle 1a whose needle tip is recessed into the cloth at the needle drop point Na. Next, when the presser foot 89 is lowered onto the throat plate and the pedal is depressed again, stitches are continued to be formed only by the outer needle 1a in response to the activation signal from the activation switch LSW.

(l B) The needle 1a restarted from the spindle rotation angle A point at the needle drop point Na gradually rises, moves upwards above the needle plate, and moves forward in the cloth feeding direction toward the next needle drop point, and then While this needle is located above the throat plate, the thread take-up 5 rises and the needle thread T
The needle thread control circuit T is closed by a specified signal from the setting switch WSW when a start signal is generated.
ea acts, the rotary solenoid 24 acts for a certain period of time via the electromagnetic actuation circuit MAR, moves the effecting body 20 to the left in FIG. After making it impossible to unwind the thread Ta, the action piece 2
2 is pushed by the bottle 21 and rotates around the spindle 18, moving the catching part 22c along the elongated hole lO, and the needle thread Ta is pushed into the catching part 2.
2c and bends to pull back the needle thread Ta that continues to the needle la side.

Therefore, the needle thread Ta due to the rise of the thread take-up 5 at the outer corner
When pulling up the needle thread Ta, the amount of lifting of the needle thread increases only when the needle thread Ta is bent by the catching part 22c, and the bobbin thread Ua is sufficiently pulled up to form a seam knot point on the cloth.

When a three-stitch stitch is formed by the outer needle 1a after turning the fabric, the lower thread U of the inner needle 1b that is let out at the edge of one needle
b is gradually retracted by the absorption of the bobbin thread of the hook, and when the upper position signal of the third needle is generated, the outer needle la is located corresponding to the inner corner Nb, and in relation to the generation of the upper position signal of the third needle. The electromagnet M is connected to the corner stitching control circuit NC via the electromagnetic actuating circuit MAI.
g1 (87) and rotates the engaging body 84 clockwise in FIG.
a, the operating lever assembly coaxial with the cam plate 8z returns to the intermediate position, returns the left needle bar 2b to the operating state, and the operating lever 4 returns to the intermediate position. 2 The needle thread control circuit 'I'ca is activated by the off signal from the sewing state detection switch MI SW, and the electromagnetic actuating circuit M
1. The rotary solenoid 17 is operated for a certain period of time via A2. Move the effecting body 15 to the left in FIG.
moves along the elongated hole 9, and after the acting part 15f acts on the regulating means of the adverb child device 7 to make it impossible to pay out the needle thread Tb, the one-needle thread Tl) is caught by the catching part 15c and bent (7, Needle 1
Pull back the needle thread Tb that continues on the bprn% side. Then, at the inner corner, the inner and outer needles are lowered together from the upper position, and the needle thread T of the thread take-up 5 is lowered.
a, needle thread Tb by the catching part 15c when pulling up Tb
The needle thread Tb of the inner needle ib increases by the amount of bending, and the bobbin thread Ub is pulled up sufficiently to create a seam knot point on the cloth.

As shown in Figure 14.15, when the right needle 1a becomes the inside needle and turns the cloth clockwise, the point at which the resting needle becomes the right edge 1a is different from the case in Figure 12.18. Since the values are different, the needle detection switch M2SW is turned off, and the thread σ1 lifting means 12 corresponding to the needle thread Tb of the left needle 1b acts at the needle drop point Nθ at the outer corner 1, and at the needle drop point Nθ at the inner corner. At Nf, the needle thread control circuit TC8 controls the thread pulling means 19 corresponding to the needle thread Ta of the right needle 1a to operate.

When the setting switch rsw is operated and the first designated signal is generated, the needle thread control circuit TCI is closed, and even if a start signal is generated at the outer corner, both thread pulling means 1 are closed.
2.19 does not operate, and the needle thread control circuit is configured such that one of the thread pulling means 12 or 19 corresponding to the inner needle is operated by a signal from the sewing state detection switch MISW at the inner corner (?0) U1 section. Controlled by CTI.

Further, when the setting switch OSW is operated and the second designation signal is generated, the needle thread control circuit TC2 is closed, and one of the thread pulling means 12 or 19 corresponding to the outer needle is activated by the generation of the start signal at the outer corner. , the needle thread control circuit TC2 controls so that both thread pulling means do not operate at the inner corner.

Depending on the thickness of the fabric and the type of top and bottom threads, the needle thread Ta may be used to raise the thread tension at the inner and outer corners using means 12 and 19.

Although it is necessary to change the amount by which Tb is raised, this can be done by rotating the operating knob 130.81. In other words, by rotating the knobs 80 and 131, one note)
Support shaft 26,2? move forward and backward in the axial direction separately, and the support shaft 2
The regulating bodies 28 and 29 fixed at 6.27 are the regulating portions 15e of the effecting bodies 15.20, respectively.

At 2nd, the opposing position of the -2,11 Otsukuni diagonal cam surface becomes diamond-shaped, and the amount of movement of the effecting body 15.20 changes due to the change in the diameter of the cam surface. Therefore, the amount of needle thread pulled out of the catching parts 15c and 22c can be adjusted separately.

In this example, corner stitching is performed based on the corner stitching control device described in Japanese Patent Application No. 51-60880. Corner stitching can be controlled by controlling the driving speed.

Alternatively, the rotary solenoid 17.24 may be controlled.

In addition, in this embodiment, the needle thread is pulled up by the thread σ] lifting means at the corner, but it is arranged in relation to the bobbin thread path between the bobbin thread outlet of the hook and the needle hole of the throat plate. A means for feeding out the bobbin thread from the hook side is provided, and it works when the thread take-up rises after the cloth turns when forming corner stitches to feed out the bobbin thread, so that the bobbin thread tension corresponds to the needle thread tension to ensure that the needle thread is fully loaded. σ
It may be possible to make it so that it can be pulled up by 1, that is, the pulling force in the direction of arrow a in FIG. 10 is small.

Also, thread pulling means π V1 needle suya bi + + old + n
4. -p Instead of the one in this embodiment, the thread of the needle thread supply source is held at the corner to reduce the amount of feed and increase the amount of needle thread pull on the needle side by the thread take-up compared to when sewing straight lines. It may be set to

Further, the thread pulling means 12.19 is not limited to the present embodiment shown in FIGS. 2 and 8, but may be any device that bends the needle thread path individually.

This thread drawing means can be used as a thread drawing means for thread cutting in a chain stitch sewing machine or the like.

Furthermore, although this embodiment has been described using a needle-feed lockstitch sewing machine, it may also be implemented in a two-needle sewing machine that does not have a needle-feeding mechanism as long as it is limited to the inner corner.

As described above, according to the present invention, in the needle feed sewing machine, the tension of the needle thread is adjusted so that the knot between the needle thread and the bobbin thread is located on the cloth only when the first stitch is formed after the cloth is rotated. is larger than the tension of the bobbin thread, and at the inner corner of a two-needle sewing machine, the knot between the needle thread and the bobbin thread is made to close to the cloth only when the first stitch is formed when one needle is reactivated. By making the tension of the needle thread of one needle greater than the tension of the bobbin thread so that the needle is located at Since it is possible to increase the amount of needle thread pulled up during sewing, the seam knots at the corners are pulled into the cloth to prevent ``tangling'', resulting in the effect of making the seams neater and significantly improving the quality of the product. It will be done.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a needle feed lockstitch sewing machine with two needles according to the present embodiment, and FIG. 2 is a thread pulling body 12 related to the needle thread Tb.
8 is a front view of the thread pulling body 1 related to the needle thread Ta.
9 is a front view, FIG. 4 is an end view between A and A in FIG. 2, FIG. 5 is an explanatory diagram of the needle thread path related to the present application, FIG. Electric circuit, Fig. 8 is an explanatory diagram showing a motion diagram of a needle feed sewing machine, Fig. 9 is an explanatory diagram showing a lock stitch, Fig. 10 is an explanatory diagram showing corner stitching by a needle feed lock stitch sewing machine, Fig. 11 Figure 12.18 is an explanatory diagram showing corner stitching with a twin needle, and Figure 12.18 is an explanatory diagram of corner stitching with the left needle as the inner needle on a twin needle feed sewing machine.
Figures 14, 15, and 16 are explanatory diagrams of the case where corner stitching is performed using the right needle as the inner needle in a twin needle feed sewing machine. Name of agent Patent attorney Nagoya - Yu

Claims (1)

[Scope of Claims] 1) In a needle-feed lockstitch sewing machine that moves the fabric along a straight line and knots the needle thread and bobbin thread to form a lockstitch line, the needle passes through the fabric after the fabric is transferred. When the fabric is stopped at a certain angle, the fabric is rotated at a specific angle around the needle, and then the fabric is further transferred, the needle thread and bobbin thread are A method of corner stitching on a lockstitch sewing machine in which the tension of the needle thread is greater than the tension of the bobbin thread so that the knot of the needle is located on the cloth. 2) In a lockstitch sewing machine that transports the fabric along a straight line, the needle threads and bobbin threads of two needles that are parallel to and intersecting the fabric feeding direction are knotted to form two lockstitch lines. After transferring the fabric, one needle is placed above the fabric and inactive, only the other needle is activated to transfer the fabric, and then the fabric is stopped with the other needle penetrating the fabric, and the fabric is centered around the other needle. Rotate one needle at a specific angle so that the seam line is on the inside of the corner, then roughly transfer the fabric until the other needle is in the position corresponding to the non-operating position of one needle. When reactivating the needle to transfer the fabric, only when forming the first stitch when reactivating one needle, adjust the needle thread of one needle so that the knot between the needle thread and the bobbin thread is located on the cloth. A method of corner stitching on a lockstitch sewing machine in which the tension is greater than the tension of the bobbin thread.