TWI498467B - A sewing machine and a method of sewing the starting portion of the seam with such a sewing machine - Google Patents

Description

Sewing machine and method for sewing seam starting portion with such sewing machine Field of invention

The present invention relates to a sewing machine according to the preamble of claim 1 of the scope of the patent application. The invention also relates to a method of sewing a seam starting portion with such a sewing machine.

Background of the invention

A sewing machine of this type is known from EP 2 028 311 A2 and DE 102 34 251 A.

Summary of invention

Accordingly, it is an object of the present invention to ensure that a small length of the upper line at the beginning of the seam is protruded from the seam in a reliable manner in operation and that this is desired to be achieved at a low structural cost.

According to the invention, the object is achieved by a sewing machine having the features defined in claim 1 of the scope of the patent application.

According to the invention, it is recognized that the provision of the wire-drawing device between the wire rod and the upper thread clamp enables the excess thread caused by the downward movement of the wire rod to be pulled back, with the aid of the thread in the case of the sewing seam starting portion. The rod pulls the upper thread back to a certain extent in the sewing material, so that only a small portion of the starting portion of the upper end of the upper end of the upper thread protrudes from the sewing material. Here, the length at which the upper thread is pulled back corresponds to the thread difference caused by the cable pulling device. Further, the free end portion of the upper thread as the upper end of the upper thread can be pulled under the sewing material so as not to affect the appearance of the sewn material to be sewn. Thereby, a visually satisfactory seam starting portion is obtained without further shortening the protruding free end of the upper thread by cutting. This is particularly advantageous in applications where particular attention is paid to the visual quality of the seam, such as when sewing the leather of the interior components of the motor vehicle. The upper wire tensioning device can be divided into an upper wire claiming device and an upper wire pretensioning device.

The wire drawing device according to item 2 of the patent application can be integrated in the upper wire guiding unit at a low structural cost. Alternatively, the wire drawing device can also be designed to have a wire hole that can be linearly displaced transversely to the direction of travel of the wire. The drive for displacing the wire holes can be realized by means of a lifting cylinder or a lifting electromagnet. The positioning drive for the arm of the wire pulling device may comprise a stepper motor.

The wire arrangement effect of the wire drawing device is optimized according to the hole arrangement scheme described in claim 3 of the patent application. Preferably, the two opposite-frame fixed wire holes are arranged in the vicinity of the swingable wire hole. The distance between the swingable wire hole in the neutral position/inactive position and the wire holes fixed to the two opposing frames may be less than 2 cm or less than 1 cm.

According to the arrangement of the wire drawing device described in claim 4, the wire drawing device and the upper wire clamp can be integrated in a structural unit which can be mounted together.

Just one upper clamp reduces the cost of construction and the cost of control when the sewing machine is in operation.

The advantages of the method according to items 6 and 7 of the patent application scope correspond to the contents of the previous contact product description. The Gegen-Drehposition can be reached after the shuttle tip has rotated at least 180° after the gripping position, for example after one of the tips has turned 240 or 245°. Since the clamping position is maintained during the rotation of at least a part of the shuttle after the upper thread is grasped by the shuttle/snap hook/hook device (Greifer), the end of the thread is used at the beginning of the seam at the beginning of the thread. Pull down to pass the sewing material. The tensioning of the upper thread when the cable pulling device is displaced from the neutral position to the cable position results in the upper wire at the beginning of the seam with the wire bar released when the wire bar is subsequently lifted again. Pulling back a length value specified by the thread difference of the upper line, the thread difference is caused by the shift of the wire pulling device. The shifting of the wire pulling device from the neutral position to the wire position can be performed during the first sewing of the line seam starting portion. Alternatively, the shifting can also be carried out during the second sewing at the beginning of the sewing seam, during the third sewing or during a later sewing. The cable puller can be returned to the neutral position from the cable position during subsequent sewing operations in a small incremental manner. This return can also be made at the end of the sewing process. For example, the shift to the neutral position is performed at the end of the tangential process of the sewing machine.

The time delay according to item 8 of the scope of the patent application has been proven to ensure that the operation is reliably pulled back on the line at the beginning of the seam. The time delay should not be lower than a certain minimum value, so that the operation is reliably performed.

The absolute time delay according to item 9 of the scope of the patent application has proven to be particularly suitable for ensuring reliable operation of the wire drawing device.

The unloading of the press device/presser according to item 10 of the scope of the patent application prevents the upper wire from being undesirably pinched by the press device when the shuttle is pulled downward through the upper thread of the sewing material.

Simple illustration

Embodiments of the invention are explained in more detail below with the aid of the drawings, in which:

Figure 1 is a front perspective view of the sewing machine;

Figure 2 is a view showing a portion of the upper thread guiding unit of the sewing machine according to Fig. 1 at the "0° needle bar top dead center" spindle position in a scale enlarged with respect to Fig. 1;

Figure 3 is a view showing a portion of the upper thread guiding unit of the sewing machine according to Fig. 1 at the "205° looping stroke" spindle position in a scale enlarged with respect to Fig. 1;

4 is a view showing a portion when the upper thread guiding unit of the sewing machine according to FIG. 1 is in the "300° upper thread clamping start" spindle position in a scale enlarged with respect to FIG. 1;

Figure 5 is a view showing a portion of the upper thread guiding unit of the sewing machine according to Fig. 1 when the "325° wire pulling device is activated" spindle position, in a scale enlarged with respect to Fig. 1;

Figure 6 is a view showing a portion of the upper thread guiding unit of the sewing machine according to Fig. 1 at the "60° bar top dead center" spindle position in a scale enlarged with respect to Fig. 1;

Figure 7 shows a schematic view of a vertical section taken along the seam plane defined by the upper and lower threads, with the initial seam portion having a free upper end.

Detailed description of the preferred embodiment

The sewing machine 1 has an upper arm 2 and a shell-shaped lower substrate 3 which are connected by a column 4 into a C-shaped frame. A spindle 5 (see Fig. 2) is mounted in the arm 2, which can be driven by a motor by means of a belt drive housed in the column 4. The motor is connected to the central control device 6, which is schematically shown in Fig. 1 in the upper arm 2, but the central control device can also be placed in other positions, even outside the sewing machine 1 And connected to the sewing machine, for example, by a cable bundle. The needle bar 7 is driven up and down when guided by the spindle 5, and a needle 8 is attached to the lower end portion of the needle bar. The upper thread 9 (see Fig. 2) passes through the eyelet of the needle 8.

A shuttle 10 is arranged in the base plate 3, and the shuttle 10 can be rotationally driven in a conventional manner under the guidance of the spindle 5 about a vertical axis of rotation 11 (see Fig. 2). The bottom line storage device 13 (see Fig. 7) is located in the bobbin case or the winding box 12 of the shuttle 10.

Fig. 2 shows in detail the guidance of the upper thread 9 of the sewing machine 1. Viewed from the eyelet of the needle 8, in the reverse upper wire transport direction, i.e., the upstream storage side line extension route, a first upper wire clamp 14 is provided, the first upper wire clamp 14 including a displacement relative to the base body 16 thereof. Splint 15. The base body 16 is a mounting plate provided on the head of the sewing machine 1. The first upper clamp 14 is in communication communication with the control device 6 and is displaceable between a clamping position in which the upper thread 9 is clamped at the position of the first upper clamp 14 and a loose position in which The first upper clamp 14 releases the upper thread 9 in the loose line position. In the region of the first upper clamp 14, the upper thread 9 extends substantially vertically.

The position of the passage of the upper thread 9 through the first upper clamp 14 can be specified by means of a plurality of threading openings 17 in the base body 16. In the illustrated embodiment, the upper thread 9 passes through the second right threading opening 17 on the right side, which is one of a total of five threading openings arranged transversely to the line conveying direction.

A wire rod 18 is provided upstream of the first upper wire clamp 14, the up and down movement of which is also guided through the main shaft 5 in a known manner. Between the wire rod hole 19 provided on the free end portion of the wire rod 18 and the first upper wire clamp 14, the upper wire 9 also passes through the guide hole 20 which is disposed above the base body 16 in Fig. 2 On the end.

Upstream of the wire rod 18, the upper wire 9 passes through the upper wire claiming device 21. The upper wire claiming device 21 comprises two claiming grippers 22 which operate in a known manner and are arranged directly one after the other in the direction of the upper thread transport. The online claiming device 21 is in communication with the central control device 6. When the tensioning device 22, that is, the tightening air cylinder, is lowered by the control device 6, the tensioning device 22 causes the upper thread 9 to be at a predetermined thread tension. The tight wire cylinder is not shown in the drawings. It is claimed that the tensioner 22 can also be used to clamp the upper thread 9 at the position where the tensioner 22 is claimed.

Between the upper threading tensioning device 21 and the wire rod 18, the upper thread 9 passes through another guiding hole 23, which can be displaced in a configurable manner transverse to the upper thread conveying direction.

In the extension of the upper thread 9, the wire pulling device 24 is arranged between the shuttle 10 and the wire rod 18, in particular between the needle 8 and the wire rod 18, more precisely the upper wire clamp 14 and the wire rod 18 between. The wire drawing device 24 has a pivotable arm member 25 that is hinged to the splint 15 of the upper wire clamp 14 via a swing joint 26. The wire pulling device 24 is thus mounted to the clamping plate 15 of the upper wire clamp 14. The arm member 25 of the wire drawing device 24 has a wire hole 27 at its free end, which wire hole can be transverse to the wire travel direction of the upper wire 9 on two oppositely fixed guide holes 28 disposed on the base body 16. Move between. The arm member 25 is changeable between a neutral position shown in FIG. 2 and a cable position shown in FIG. 3, in which the upper thread 9 is between the two guide holes 28 fixed to the opposite frame. That is, there is a thread between the needle 8 and the wire rod 18, which is a thread difference from the corresponding thread when the upper thread 9 is in the neutral position of the arm member 25. In the illustrated embodiment, the thread difference is, for example, 20 millimeters.

The two opposite frame-mounted guide holes 28 allow the upper wires 9 to have the same regardless of the extension route between the two opposite frame-mounted guide holes 28, regardless of whether the arm member 25 is in the pull-wire position or in the neutral position. The extension of the route.

The arm member 25 can be displaced between the neutral position and the cable position by means of an electromagnetic drive, which in turn is communicatively connected to the control device 6. As an alternative to the electromagnetic drive, the arm member 25 can also be driven pneumatically or by a stepper motor.

An upper line pretensioning device 29 is provided upstream of the upper wire claiming device 21, which is also operated in a known manner and is communicably connected to the control device 6. The upper wire claiming device 21 and the upper wire pretensioning device 29 having two claiming grippers 22 are also mounted on the mounting plate 30, which in turn is mounted on the arm 2 (see Fig. 1).

Upstream of the upper pretensioning device 29, the upper thread 9 passes through a threading opening 31 which is provided in the mounting plate 30 in the edge region of the upper portion of Fig. 2 which is bent forward by about 90°. An upper bobbin, not shown in detail, serving as an upper line storage device is provided upstream of the threading opening 31.

Figures 2 to 6 show the transient rotational position of the spindle 5. On the hand wheel 32, which is connected in a rotationally fixed manner to the end face of the spindle 5, a corner scale 33 is provided, which indicates a complete revolution of the spindle 5 with an angular graduation scale divided into 360. The following description relates to the indexing position of the corner scale 33, respectively.

A sewing plane is defined by the sewing material 34 (see Fig. 7) in a flat position on the needle plate 35 of the sewing machine 1.

Figure 2 shows the 0° spindle position. In this spindle position, the needle bar 7 is at the top dead center. This position is selected at the start of sewing, i.e. at the beginning of the seam, since the passage for inserting the seam 34 below the needle 8 is greatest at this position.

In the 0° position, the upper clamp 14 is in the loose position. The upper line asserts that the tightening device 21 is activated. The wire drawing device 24 is in a neutral position. The upper thread pretensioning device 29 is activated. The mast 18 is located in a path upward from its bottom dead center.

Figure 3 shows the spindle 5 in the 205° position. In this position, the needle bar 7 returns a further distance from its bottom dead center reached at 180°, thereby forming a loop that is not visible in Fig. 3 next to the eyelet of the needle 8. In the 205° position, the edge of the shuttle 10, which is also invisible in Fig. 3, can be engaged into the loop and subsequently drive the upper thread 9.

In the 205° position, the upper clamp 14 is activated into the gripping position. The upper line asserts that the tightening device 21 is activated. The wire pulling device 24 is in a neutral position. The upper thread pretensioning device 29 is activated. The mast 18 is located on a path leading to its bottom dead center. The wire rod 18 has left its top dead center, resulting in an excess of wire between the upper wire clamp 14 and the upper wire claiming device 21, that is, where the wire is not tensioned as shown in Fig. 2. Such a line excess is almost twice the distance of the mast hole 19 from the top dead center of the mast 18 to the 205° position shown in FIG. From the 205° position, the shuttle 10 begins to pull the upper thread out with the tip of the wire that engages the wire loop. Since the upper grip 14 is in the gripping position, the upper thread 9 cannot be replenished from above, so that when the upper loop is pulled out by the shuttle tip, the free end of the upper thread 9 passing through the sewing material is pulled downward. In order to prevent the presser foot 37 from clamping the free end 36 of the upper thread 9 (see Fig. 7) on the sewing material, the presser foot 37 is unloaded in the 205° position, so that the presser foot 37 is placed flat on the sewing material 34 without load.

Figure 4 shows the 300° spindle position. In this 300° position, the mast hole 19 is located in the region of the bottom dead center. Here, the pulling of the upper thread by the shuttle 10 as described above is continued. In this spindle position, the upper thread 9 passing through the sewing material is pulled downward by means of the shuttle 10. In the 300° spindle position, the presser foot 37 can be loaded again, so that the effective unloading of the presser foot 37 between the 205° and 300° spindle positions is no longer effective at this time.

At this time, the upper clamp 14 is transferred to the clamping position. The upper thread asserts that the tensioning device 21 is activated and the upper thread 9 is kept under tension. The arm member 25 of the wire pulling device 24 is in a neutral position. The upper thread pretensioning device 29 is activated. In the 300° position, the free end 36 of the upper thread 9 is pulled downward by the shuttle 10.

On the way between the 205° spindle position and the 300° spindle position, the shuttle 10 is pulled downward through the free end 36 of the upper thread 9 of the sewing material 34. In the event that the spindle continues to operate, the wire rod 18 pulls back the upper thread 9 in the sewing material 34, as more clearly shown below. Thus, the free end portion 36 projects from the sewing material 34 by a correspondingly smaller line length.

Figure 5 shows the 325° spindle position when (forming) the next seam. The spindle 5 is further rotated through 120° (actually 480°) in the sewing direction with respect to the position according to Fig. 3.

In the 325° position, the upper clamp 14 is in the loose line position. The upper line asserts that the tightening device 21 is activated. The arm member 25 of the wire pulling device 24 is now displaced to the wire position.

In the 325° position, the mast hole 19 is in an initial upward motion after the bottom dead center. By shifting the wire pulling device 24 to the wire position, the excessive upper wire in the region still in the wire rod hole 19 in the position according to Fig. 2 is pulled toward the wire hole 27 of the wire drawing device 24. At this time, there is no slack excess line between the rod hole 19 and the upper thread clamp 14 on the upper thread 9 line, that is, the upper line is almost tensioned in Fig. 6.

In the 325° position, the shuttle 10 is also rotated further about the axis of rotation 11 relative to the position according to FIG. 3, ie by 240° (actually 960°) about the axis of rotation 11 . In a further operation of the spindle, the wire rod 18 pulls the upper thread 9 in the region of the formed seam back by a quantity which causes the upper thread 9 to have an extended extension in the region of the cable pulling device 24 at this time.

Figure 6 shows the 60° spindle position. The needle 8 is in the downward path. The upper clamp 14 is in the loose position. The upper line asserts that the tightening device 21 is activated. The upper thread pretensioning device 29 is activated. The wire pulling device 24 is in the cable position. In all further of the formation of the seam, the cable puller 24 remains in the cable position. Alternatively, during further formation of the seam, the wire pulling device 24 may also lead an increment in the direction of the neutral position, one by one, respectively, between the pull position and the neutral position of the pull device. A small part of the entire journey. The increment of each needle is so small that each incremental adjustment process of the wire pulling device 24 returns a thread that is less than the stitch length. Thus, in the event that no further seam formation is affected, the additional thread is returned by the movement of the needle bar 18, which is caused by the wire pulling device 24 of the upper wire 9 displaced to the wire position. The curved distance.

When the end 36 of the upper thread 9 is not knotted, i.e., free, the operation of the wire pulling device 24 begins from the 0° spindle position according to Fig. 2. A double layer of stitching 34 is inserted in this position. The status information "stripe start" is stored in the control device 6. From the position according to Fig. 2, as shown in Fig. 7, sewing of the seam in the sewing material 34 is started. In and only during the initial process, the wire puller 24 is displaced to the pull wire position as described above. Corresponding to the above, the wire pulling device 24 is displaced from the neutral position to the wire position when the second sewing is formed. In all subsequent seam formations, the wire puller 24 is continuously held in the pull wire position. In the 325° spindle position, the wire pulling device 24 is activated into the wire position, which in the further operation is pulled back through the free end 36 of the upper thread 9 of the sewing material 34 by the wire rod 18, thereby making it shorter . Alternatively, the wire pulling device 24 can also be displaced from the neutral position to the cable position when the first sewing seam, the third sewing seam or the rear seam is formed.

After the wire pulling device 24 is first displaced from the neutral position to the wire position and returned, the state information "sew start" stored in the control device 6 is converted into "continuous seam". After the tangential process, the control device 6 is re-shifted to "sew start". Status information is queried during further sewing. The wire pulling device 24 is only activated when the status information is "slot start". At the end of the sewing process and, if necessary, after the tangential process, the wire pulling device 24 is reset to the neutral position. This can also be carried out incrementally during the formation of the in-line seam as described above.

The length of the free end 36 projecting from the seam 34 can be defined by the angular position of the arm member 25 in the wire position. In particular, when the arm member 25 is driven by the stepping motor, a plurality of line end lengths can be preselected in the control device 6. In the cable position, the angular position of the arm member 25 controlled by the control device 6 is determined in accordance with the selected length of the wire end. Alternatively, the length of the wire forming the length of the respective wire end can also be set by a mechanical stop for the arm member 25.

50 ms after the upper clamp 14 is actuated, the wire pulling device 24 is displaced from the neutral position to the cable position.

A time delay is set by the control device 6, which is mainly dependent on the shift time for which the upper clamp 14 is reliably displaced.

The entire process of the first seam at the beginning of the seam - during which the cable puller 24 is displaced from the neutral position to the cable position and returned - at a fixed spindle speed, the fixed spindle speed being less than Other operating speeds of the spindle 5. This small rotational speed of the spindle is also specified by the control device 6. Since the first sewing is formed at a fixed spindle speed, a constant value of, for example, 50 ms is set for the time delay of shifting the wire pulling device 24 after the upper wire clamp 14 is driven.

In other words, the method of sewing the seam starting portion can be described as follows: First, an upper loop is formed. Next, in the gripping rotational position of the shuttle tip, the upper loop is grasped by the tip of the shuttle 10. Then, the shuttle tip of the shuttle 10 is rotated about the swing box of the shuttle 10 by about 240° to 250°, especially 240° until it reaches the rotation of the reverse rotational position opposite to the grasping rotational position, using the shuttle 10 The tip of the shuttle pulls the upper thread 9 out. Starting from the gripping position, the shuttle tip of the shuttle 10 is rotated all the way to the reverse rotation position, i.e., the shuttle box around the shuttle 10 is rotated at least half a turn. After the shuttle tip of the shuttle 10 reaches the reverse rotational position, the cable puller 24 is displaced from the neutral position to the pull position.

The thread difference due to the displacement of the arm member 25 between the neutral position and the wire position can be specified according to the thickness of the sewing material 34. The thickness of the suture 34 can be set by the user or can also be measured by a thickness sensor not shown in the drawings. In order to process the measured seam thickness values and to transfer the thread difference setpoint to the cable puller 24, the control device 6 can also be communicatively coupled to the seam thickness sensor.

For the tangential process at the end of the sewing process, the tensioner 22 can be made to form an air gap (lifting) so that there is no line tension at the claimer 22. The tensioner 22 is claimed to produce the thread tension necessary for sewing during the sewing process. In conjunction with the displacement of the wire pulling device 24 from the neutral position to the wire position, the tensioner 22 can be transferred into the clamping position, thereby ensuring that the upper wire 9 is pulled back from the free end 36. It is claimed that the wire clamping function of the tensioner 22 can be used when the upper thread 9 in the sewing material is subjected to a large friction sewing feed.

2. . . Upper arm

3. . . Substrate

4. . . Column

5. . . Spindle

6. . . Central control equipment

7. . . Needle bar

8. . . needle

9. . . online

10. . . Shuttle

11. . . Rotation axis

12. . . Winding box

13. . . Bottom line storage device

14. . . Upper clamp

15. . . Splint

16. . . Matrix

17,31. . . Threading port

18. . . Wire rod

19. . . Bar hole

20,23,28. . . Guide hole

twenty one. . . On-line claim

22‧‧‧Proposition

24‧‧‧ Pulling device

25‧‧‧arms

26‧‧‧swing joint

27‧‧‧Line hole

29‧‧‧Upline pretensioning device

30‧‧‧Installation board

32‧‧‧Handwheel

33‧‧‧ Corner scale

34‧‧‧ sewing material

35‧‧‧ needle board

36‧‧‧Free end

37‧‧‧Foot press

Figure 1 is a front perspective view of the sewing machine;

Figure 2 is a view showing a portion of the upper thread guiding unit of the sewing machine according to Fig. 1 at the "0° needle bar top dead center" spindle position in a scale enlarged with respect to Fig. 1;

Figure 3 is a view showing a portion of the upper thread guiding unit of the sewing machine according to Fig. 1 at the "205° looping stroke" spindle position in a scale enlarged with respect to Fig. 1;

4 is a view showing a portion when the upper thread guiding unit of the sewing machine according to FIG. 1 is in the "300° upper thread clamping start" spindle position in a scale enlarged with respect to FIG. 1;

Figure 5 is a view showing a portion of the upper thread guiding unit of the sewing machine according to Fig. 1 when the "325° wire pulling device is activated" spindle position, in a scale enlarged with respect to Fig. 1;

Figure 6 is a view showing a portion of the upper thread guiding unit of the sewing machine according to Fig. 1 at the "60° bar top dead center" spindle position in a scale enlarged with respect to Fig. 1;

Figure 7 shows a schematic view of a vertical section taken along the seam plane defined by the upper and lower threads, with the initial seam portion having a free upper end.

5. . . Spindle

7. . . Needle bar

8. . . needle

9. . . online

10. . . Shuttle

11. . . Rotation axis

12. . . Winding box

14. . . Upper clamp

15. . . Splint

16. . . Matrix

17,31. . . Threading port

18. . . Wire rod

19. . . Bar hole

20,23,28. . . Guide hole

twenty one. . . On-line claim

twenty two. . . Proposition

twenty four. . . Pulling device

25. . . Arm

26. . . Swing joint

27. . . Line hole

29. . . On-line pretensioning device

30. . . Mounting plate

32. . . Hand wheel

33. . . Corner scale

35. . . Needle plate

37. . . Presser foot

Claims (10)

a sewing machine comprising: - a frame; - a storage device for the upper thread; - a needle bar comprising a sewing needle for guiding the upper thread through the sewing material, wherein the sewing needle can be driven Moving up and down in the vertical direction between the bottom dead center and the top dead center; - a shuttle for grasping the upper thread during sewing; - a pole for looping the upper thread; - an upper clamp capable of being controlled, said The upper thread is clamped between the shuttle and the wire rod in an upper line extending route on the storage device side; - an upper thread tensioning device, wherein the upper thread tensioning device is in the upper line extending route on the storage device side Upstream of the pole, the upper thread tensioning device causes the upper thread to be under a determined line tension in an activated state; and further comprising: a wire pulling device, the wire pulling device being located at the upper wire clamp and the In the upper line extending route between the wire rods, the wire pulling device is controllably displaceable between a neutral position and a wire position, wherein - in the neutral position, the upper line is in the Between the pole and the shuttle has a first thread; -- at the cable Set, the line having a second upper thread between the rod and the loop taker, a difference between said second thread grow thread than the first thread. A sewing machine according to the first aspect of the invention, characterized in that The wire drawing device has a swingable arm member, and a wire hole is provided at an end portion of the arm member which is swingable transversely to the line extending path. A sewing machine according to claim 2, characterized in that, in the neutral position, the wire holes are arranged in an upper line extending path between two wire guiding holes fixed to the opposite frame. A sewing machine according to the first aspect of the invention, wherein the wire drawing device is mounted on a plate of the upper wire clamp. The sewing machine according to the first aspect of the invention is characterized in that the upper thread clamp is provided in the upper line extending path on the storage device side. A method for sewing a seam starting portion according to the sewing machine of claim 1 comprising the steps of: - forming an upper loop; - by means of a shuttle tip of the shuttle in a gripping rotational position of the shuttle tip Grasping the upper wire loop; - rotating the shuttle tip around the shuttle box of the shuttle for at least half a turn until reaching a reverse rotational position opposite to the grasping rotational position, by means of the shuttle The shuttle tip pulls out the upper thread; - after the shuttle tip of the shuttle reaches the reverse rotation position, the cable pulling device is displaced from the neutral position to the cable position. The method according to claim 6, characterized in that the method has the following steps: - lifting the needle bar together with the sewing needle from the bottom dead center to a looping stroke position between the bottom dead center and the top dead center To form an upper loop, The lifting is performed when the upper clamp is opened and the cable pulling device is in the neutral position; - after reaching the looping stroke position of the needle bar: driving the upper clamp to reach the clamping line Positioning and maintaining the gripping position of the upper grip during rotation of at least a portion of the shuttle after the pick and pull of the upper thread through the shuttle, wherein the upper thread is pulled out; The wire pulling device is displaced from the neutral position to the wire position, whereby when the wire rod is lowered, the upper thread is tensioned between the wire rod and the upper wire clamp; Returning the cable pull device to the neutral position. The method according to claim 6 or 7, wherein the time delay of the displacement of the wire pulling device after the upper wire clamp is controlled is set to be the rotation speed of the spindle of the sewing machine Not related. The method of claim 8, wherein the wire pulling device is displaced to the wire position about 50 ms after the upper wire clamp is driven. The method of claim 6, wherein the press device of the sewing machine is unloaded at least when the upper thread is pulled out.