KR200482460Y1

KR200482460Y1 - Sewing machine and method for sewing a beginning of a seam with a sewing machine of this type

Info

Publication number: KR200482460Y1
Application number: KR2020120001759U
Authority: KR
Inventors: 엔스 요한
Original assignee: 뒤르콥 아들러 악티엔게젤샤프트
Priority date: 2011-03-07
Filing date: 2012-03-07
Publication date: 2017-01-25
Also published as: EP2497852B1; EP2497852A1; CN202530278U; TWM445592U; DE102011005198A1; JP3175658U; KR20120006388U

Abstract

The sewing machine has a supply portion for the upper thread (9). A needle bar 7 having a sewing needle 8 is used to guide the upper thread 9 through the product to be sewn. The hook 10 is used to hold the upper thread 9 during needle sweat formation. The upper thread clamp 14 is disposed on the upper thread path on the supply side of the hook 10 and the thread lever 18. [ The upper thread tensioning device 21 is disposed in the upper thread path on the upstream side of the upper thread clamp 14. The thread take-out device 24 is disposed between the thread lever 18 and the upper thread tensioning device 21. This thread take-out device can be moved under control between the neutral position and the thread take-out position, and the path of the upper thread 9 at the thread take-out position is longer than the thread position difference at the neutral position. As a result, the upper thread portion protruding from the product to be sewn in the sewing machine becomes shorter at the start of the seam in stable operation.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewing machine and a sewing machine,

The present invention relates to a sewing machine comprising a housing, a supply portion for an upper thread, a needle bar having a sewing needle for guiding an upper thread through a product to be sewn, wherein the sewing needle is vertically moved up and down vertically and driven between a bottom dead point and a top dead point, A threaded hook for holding the upper thread, a threaded lever for pulling the loop of the upper thread, an operable upper thread clamp in the feed thread upper thread path between the hook and the thread lever, and a thread tension in the upper thread, To a sewing machine including an upper thread tensioning device in an upper thread path on a supply side.

The present invention also relates to a method for sewing the beginning of a seam with this sewing machine.

Such sewing machines are already known from EP 2 028 311 A2 and DE 102 34 251 A.

The object of the present invention is to ensure a short upper thread protruding from the product to be sewn at the beginning of the seam in a stable operation and to be structurally inexpensive.

The above object of the present invention can be attained by a needle thread transferring apparatus comprising a neutral position in which an upper thread takes a first thread path between a thread lever and an upper thread tensioning unit and a second thread path between an thread lever and an upper thread tensioning unit, And a yarn withdrawing device which can be moved through the control between the two positions, wherein the yarn withdrawing device is in the upper yarn tensioning unit and the yarn levers between the upper and lower yarn tensioning units.

It has been found in accordance with the present invention that the thread take-off device between the thread lever and the upper thread tensioning device causes the possibility of withdrawing the surplus produced during the downward movement of the thread lever and then by the thread lever to sew the beginning of the thread , The free end of the upper thread causes the possibility of pulling the upper thread backward from the product to be sewn to such a degree that it protrudes slightly from the product to be sewn at the beginning of the seam. The upper thread is drawn back in the process by a length corresponding to the thread path difference caused by the thread take-off device. Also, the free end of the upper thread, which represents the beginning of the upper thread, is drawn below the product to be sewn, so that it does not detract from the appearance of the sewn product. As a result, the beginning of the seam is visually satisfactory without having to shorten it by cutting off the protruding free ends of the upper thread. The advantages are, for example, in applications where visual seam quality is particularly notable when sewing leather from interior elements of a car. The upper thread tensioning device may be divided into an upper thread tensioning device and an upper thread pretensioning device or an additional tensioning device. The upper thread tensioning unit that predetermines the region of the upper thread path along which the thread take-off device is disposed, together with the thread lever, is an element of the upper thread tensioning device, that is, it is not an element of the upper thread pretensioning device or an additional tensioning device.

A thread take-up device having a pivotable extension arm pivotally moved in a direction perpendicular to the thread path can be incorporated into the upper thread guide at low cost in terms of structure. Alternatively, the thread take-out device having the threaded eyelet which can be linearly displaced in the direction perpendicular to the thread path can be constructed. A driving device for displacing the threaded eyelet can be achieved by a lifting cylinder or a lifting magnet. The positioning drive device for the extension arm of the thread take-out device may have a stepping motor.

In the neutral position, the thread placement in the thread guide path between the two yarn guiding eyelets fixed to the housing optimizes the thread drawing effect of the yarn drawing device. The two thread guide eyets fixed to the housing are preferably arranged in a thread path near the pivotable thread eyelet. The space between the pivotable threaded eyelet in the neutral position and the two threaded eyelet fixed to the housing may be smaller than 2 cm or smaller than 1 cm.

To be precise, an upper thread clamp results in reduced structural costs and reduced control costs during operation of the sewing machine.

The arrangement of the upper thread tensioning device in which the upper thread tensioning device 21 is disposed only in the thread path between the thread take-out device 24 and the upper thread supply part facilitates the operation sequence when operating the thread take-out device. The operation of the thread take- This is because synchronization of the operation of the device is unnecessary.

Alternatively, a plurality of upper thread tension units may be provided, such that the upper thread tensioning device has one of a plurality of upper thread tensioning units, or, in other words, an upper thread tensioning unit disposed in the yarn path between the thread lever and the thread take-off device. This type of design of the upper thread tensioning device results in a reliable constant thread tension during the sewing operation. This thread take-out apparatus can be disposed between the upper thread tensioning units. In general, adequate installation space is used to accommodate the drawer.

Advantages of the method for sewing the beginning of a seam with a sewing machine according to the invention with the following steps are already in agreement with the above description with the device:

Forming an upper thread loop,

Holding the upper thread loop with the hook tip of the hook at the rotational gripping position,

Withdrawing the upper thread from the hook tip of the hook during at least half of the rotation of the hook tip around the hook housing of the hook until the rotationally opposite position of the rotary gripping position is reached,

Moving the yarn withdrawal device from the neutral position to the yarn withdrawal position after reaching the reverse rotation position of the hook tip of the hook.

Forming an upper thread loop by raising the needle bar toward the loop lift position between the bottom dead center and the top dead center with a sewing needle from a bottom dead center, the thread being formed by an open upper thread clamp and a yarn withdrawal device in a neutral position,

Maintaining the thread clamping position of the upper thread clamp for at least a portion of the hook rotation after the thread clamping position of the upper thread clamp is reached and held by the hook after reaching the loop lift position of the needle bar,

Moving the yarn withdrawal device from the neutral position to the yarn withdrawal position such that the upper yarn is pulled tight between the yarn lever and the upper room tensioning unit with the lower yarn lever,

Setting the thread take-out device to the neutral position.

The reversed position may be achieved after rotation of the hook tip at least 180 ° after the rotational gripping position, for example after rotation of the hook tip of 240 ° or 245 °. The upper thread end at the beginning of the seam is pulled down by the hook through the product to be sewn because of the retention of the thread clamping position for at least a portion of the hook rotation after gripping the upper thread with the hook. The fact that the upper thread is pulled out when the thread take-out device is moved from the neutral position to the thread take-out position is caused by the difference in the path of the upper thread caused by the movement of the thread take-up device when the thread lever is later lifted up when the upper thread clamp is released The upper thread can be pulled back at the beginning of the seam by a predetermined length. The movement of the yarn draw-out device from the neutral position to the yarn withdrawal position takes place during the first needle sweat at the beginning of the seam. This movement can alternatively be made during the second needle sweat, during the third needle sweat or much later during the stitching at the beginning of the seam. The return of the yarn draw-out device from the yarn withdrawal position to the neutral position can be made gradually in small steps during another sewing. This return can also be made at the end of the sewing process. Movement to the neutral position can be done, for example, in the last thread cutting process of the cutting machine.

The fact that the upper thread tension unit between the thread lever and the thread take-out unit is moved from the normal tensile force position to the smaller tensile force position when the thread take-out apparatus is moved from the neutral position to the thread take-out position is ensured in that the thread take- The upper thread is pulled back from the product to be sewn as desired. At the smaller tension position, the upper thread tension unit between the thread lever and the thread take-up unit brings the upper thread under the reduced residual thread tension compared to the normal tensile force. Alternatively, when the thread take-out apparatus is moved from the neutral position to the thread take-out position, the upper thread tension unit between the thread lever and the thread take-out apparatus may be completely inactivated.

The product pressure of the sewing machine is released from the pressure of the product pressure which is released from the pressure during the start of drawing at least the upper thread so that the upper thread is undesirably clamped by the product pressure while the upper thread is pulled down by the hook through the product to be sewn It prevents you.

According to the present invention, the short upper thread protruding from the product to be sewn at the beginning of the seam can be shortened and can be implemented at low cost in terms of structure.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings.

1 is a front view of a sewing machine;
Fig. 2 is a detailed view of an upper thread guide of the sewing machine shown in Fig. 1 at an arm shaft position "0 ° needle bar top dead center"
Fig. 3 is a detailed view of the upper thread guide of the sewing machine according to Fig. 1 at the arm shaft position "205 占 Loop Lift"
Fig. 4 is a longitudinal section of a two-ply product to be sewn along the seam plane defined by the upper and lower yarns, with the seam opening at the top thread free end.
Fig. 5 is a detailed view of an upper thread guide of the sewing machine according to Fig. 1 at an arm shaft position "300 ° non-operating upper thread clamp by hook and upper thread tension (thread lever at bottom dead center)
Fig. 6 is a detailed view of an upper thread guide of the sewing machine according to Fig. 1 at an arm shaft position "325 占 operated thread take-out device"
Fig. 7 is a detailed view of an upper thread guide of the sewing machine shown in Fig. 1 at an arm shaft position "60 ° thread lever upper dead center"
Figs. 8 to 12 are detailed views of an upper thread guide of another embodiment of a sewing machine having an additional upper thread tensioning unit in the order of arm shaft positions corresponding to Figs. 2, 3 and 5 to 7. Fig.

The sewing machine 1 has an upper arm 2 and a lower housing-like base plate 3 joined together by a stand 4 to form a C-shaped housing. The arm shaft 5 (see Fig. 2) mounted on the arm 2 can be driven by a motor through a belt drive contained in the stand 4. [ The central control device 6 connected to this motor is shown schematically in the upper arm 2 of Fig. 1, but may be arranged at another point and may also be arranged externally with respect to the sewing machine 1, To the sewing machine. Starting from the arm shaft 5, the needle bar 7 is driven to move up and down, and the needle 8 is mounted to the lower end of the needle bar. The upper thread 9 passes through the eye of the needle 8 (see FIG. 2).

A looper or hook 10 rotatably driven by a vertical rotary shaft 11 (see Fig. 2) is arranged on the base plate 3, starting from the arm shaft 5 in a conventional manner. The feed for the lower thread 13 (see FIG. 4) is located in the thread take-up housing 12 of the bobbin or hook 10 (see FIG. 4).

2 is an enlarged detail view for guiding the upper thread 9 of the sewing machine 1. The first upper thread clamp 14 having the clamping plate 15 which can be relatively displaced with respect to the body 16 of the first upper thread clamp 14 is provided on the opposite side of the needle 8 from the eye in the conveying direction of the upper thread, And is disposed in the upper thread path of the supply unit side. The first upper thread clamp 14 has a signal connecting portion to the control device 6 and a thread clamping position in which the upper thread 9 is clamped to the position of the first upper thread clamp 14, And a thread releasing position for releasing the upper thread (9). The upper thread 9 passes essentially perpendicular to the region of the first upper thread clamp 14. [

The passing position of the upper thread 9 passing through the first upper thread clamp 14 can be predetermined by the plurality of thread passing apertures 17 in the body 16. [ In the embodiment shown in the drawing, the upper thread 9 passes through a second thread passing opening 17 from the right of a total of five thread passing openings arranged in a direction perpendicular to the yarn transfer direction.

A thread lever 18 is disposed downstream of the first upper thread clamp 14 and its up and down movement is derived from the arm shaft 5 in a manner known per se. The upper thread 9 also passes through the guide eyelet 20 provided at the upper end of the main body 16 and is engaged with the thread lever eart 19 disposed at the free end of the thread lever 18 and the first upper thread clamp 14, .

On the upstream side of the thread lever 18, the upper thread 9 passes the upper thread tensioning device 21. In the embodiment according to Figs. 1 to 7, the latter has an upper thread tensioning unit which operates in a manner known per se in the form of a main tensioner 22. The upper thread tensioning device 21 has a signal connection to the central control device 6. [ The main tensioner 22 is caused to receive a predetermined thread tension by the control device 6 when the upper thread 9 is in operation, in other words, when it comes out of the seal tension ventilator cylinder. The seal tension ventilator cylinder is not shown in the drawing. The main tensioner 22 may also be used to clamp the upper thread 9 in the position of the main tensioner 22.

Between the upper thread tensioning device 21 and the thread lever 18, the upper thread 9 passes through the other displaceable guide eyelet 23, and the guide eyelet can be adjusted in a direction perpendicular to the upper thread transferring device. Between the guide eyelet 23 and the upper thread tensioning device 21, the upper thread 9 passes the thread tension spring unit 23a.

More specifically, between the thread lever 18 and the upper thread tensioning device 21, more precisely between the thread tensioning spring unit 23a and the upper thread tensioning unit 22, the thread take- Respectively. The thread take-off device 24 has a rotatable extension arm 25 which is connected by a pivot joint 26 in a mounting plate 26a fixed to the arm 2. [

Therefore, the yarn drawing-out device 24 is mounted on the mounting plate 26a. At its free end, the elongated arm 25 of the yarn withdrawal device 24 has a threaded eyelet 27, and the threaded eyelet is secured to the housing and includes two guide eyelet 28 In the direction perpendicular to the yarn path of the upper thread 9. As shown in Fig. The extended arm 25 moves between the neutral position shown in Fig. 2 and the yarn withdrawing position shown in Fig. 6, and in the yarn withdrawing position, the upper thread 9 is moved between two guide eyelets 28 fixed to the housing The yarn path between the yarn lever 18 and the upper thread tensioning device 21 takes a yarn path so that the yarn path difference is greater than the yarn path of the upper thread 9 passing through the extending arm 25 in the neutral position . In the illustrated embodiment, the yarn path difference is, for example, 20 millimeters.

The two guide eyelets 28 being fixed to the housing means that the upper eyelets 28 are secured to the two eyelets 28 fixed to the housing irrespective of whether the extension arms 25 are in the draw- Outside the path between them, the same path is taken in each case.

The extension arm 25 is moved by the electromagnetic drive device between the neutral position and the yarn withdrawing position, and the electromagnetic drive device has a signal connection to the control device 6. [ As an alternative to the electromagnetic drive device, the extension arm 25 may also be driven by air pressure or by a stepping motor.

An upper thread pretensioning device 29 may be disposed upstream of the upper thread tensioning device 21 to operate in a known manner and have a signal connection to the control device 6. [ The upper thread tensioning device 21 and the upper thread pretensioning device 29 having the main tensioner 22 are attached to a mounting plate 26a provided on the arm 2 (see FIG. 1).

In the upstream of the upper thread pretensioning device 29, the upper thread 9 passes through the thread passage opening 31 formed in the upper edge region of the mounting plate 26a in FIG. 2 and is bent forward by about 90 degrees. An upper thread bobbin is disposed upstream of the thread passing opening 31 as an upper thread supply portion although not shown in detail.

Figs. 2 to 7 show the current rotational position of the arm shaft 5. Fig. A rotary angle scale 33 is arranged on the handwheel 32 fixedly connected to the end of the arm shaft 5 and shows the total rotation of the arm shaft 5 divided at 360 angles. In each case, the angular position of the rotary angle scale 33 will be referred to below.

The plane of the product to be sewn is predetermined by the remaining position of the product 34 to be sewn on the needle plate 35 of the sewing machine 1 (see Fig. 4).

Figure 2 shows the 0 ° arm shaft position. In this arm shaft position, the needle bar 7 is at the top dead center. This position is selected at the beginning of the sewing, i. E. At the beginning of the seam, because the passage under the needle 8 is maximum to insert the product 34 to be sewn.

At the 0 [deg.] Position, the upper thread clamp 14 is in the thread releasing position. The upper thread tensioning device 21 is operated. The yarn drawing device 24 is in the neutral position. The upper thread pretensioning device 29 is operated. The seal lever 18 advances upward from the bottom dead center.

3 shows the arm shaft 5 at the 205 [deg.] Position. In this position, the needle bar 7 has slightly returned from the bottom dead center reached 180 占 again, so that an upper thread loop not shown in Fig. 3 is formed beside the eye of the needle 8. Fig. At the 205 [deg.] Position, the hook tip of the hook 10, which is also not shown in Fig. 3, engages the upper thread loop and takes the upper thread 9. [

At the 205 [deg.] Position, operation of the upper thread clamp 14 to the thread clamping position is effected. The upper thread tensioning device 21 is operated. The yarn drawing device 24 is in the neutral position. The upper thread pretensioning device 29 is operated. The seal lever 18 proceeds to the bottom dead center. Since the thread lever 18 has already been removed from its top dead point, the actual surplus does not pass the tensile force that results between the upper thread clamp 14 and the upper thread tensioning device 21, that is, have. This room surplus is about twice the path of the thread lever 18 from the top dead center of the thread lever 18 at the 205 DEG position shown in FIG. From the 205 [deg.] Position, the hook 10 begins to pull the upper thread through the hook tip engaged with the upper thread loop. Since the upper thread 9 can not be additionally supplied from above due to the upper thread clamp 14 at the thread clamping position, the free end 36 of the upper thread 9 during the withdrawal of the upper thread loop by the hook tip can be moved 34). The release of the pressure foot 37 from the pressure is actuated at the 205 [deg.] Position in order to prevent the product pressure foot 37 from clamping the free end of the upper thread 9 (see Fig. 4) The pressure foot 37 is placed on the product 34 to be sewn without load.

5 shows a 300 ° arm shaft position. At the 300 [deg.] Position, the seal lever eyelet 19 is in the bottom dead center. The upper thread tension already described above is continued here by the hook 10. In this arm shaft position, the upper thread 9 is pulled down past the product to be sewn by the hook 10. At the 300 ° arm shaft position, the pressure foot 37 is now deactivated again, that is, the pressure foot 37 is released from the pressure, which is in the operative state between the 205 ° and 300 ° arm shaft positions which are subjected again to the load.

The upper thread clamp 14 is now fed to the thread releasing position. The upper thread tensioning device 21 is operated and holds the upper thread by a tensile force. The upper thread pretensioning device 29 is operated. At the 300 [deg.] Position, the free end 36 of the upper thread 9 was pulled back down by the hook 10.

On the path between the 205 ° arm shaft position and the 300 ° arm shaft position, the hook 10 draws the free end 36 of the upper thread 9 past the product 34 to be sewn. In another path of arm shaft rotation, the thread lever 18 pulls back the upper thread 9 in the product 34 to be sewn, which becomes increasingly clear in the following description. The free end 36 then projects a smaller amount of thread length from the product 34 to be sewn.

Figure 6 shows the position of the 325 ° arm shaft in the next needle sweat. 3, the arm shaft 5 is again rotated in the sewing operation direction by 120 DEG (actually 480 DEG).

At the 325 [deg.] Position, the upper thread clamp 14 is in the thread releasing position. The upper thread tensioning device 21 is operated. The extension arm 25 of the thread take-out device 24 is now moved to the thread take-out position.

The threaded lever 19 starts to move upward after the bottom dead center at the 325 [deg.] Position. Due to the movement of the thread take-off device 24 to the thread take-out position, the upper thread surplus still in the area of the thread lever eyelet 19 at the position according to Fig. 2 is now in the threaded hole 27 of the thread tensioning device 24, Lt; / RTI > Between the thread lever lever 19 and the upper thread clamp 14, the upper thread 9 is now loosened in the vertical direction in Fig. 6, i.e., without loosening of the upper thread surplus.

At the 325 [deg.] Position, the hook 10 was also rotated again about 240 [deg.] (Actually 960 [deg.]) About the rotary shaft 11, in particular about the rotary shaft 11, The upper thread 9 is pulled back by the thread lever 18 in the other path of the arm shaft rotation, and in particular, the upper thread 9 is pulled in the area of the thread take- Loses.

Figure 7 shows the 60 ° arm shaft position. The needle 8 is in a downward path. The upper thread clamp 14 is in the releasing position. The upper thread tensioning device 21 is operated. The upper thread pretensioning device 29 is operated. The thread take-out device 24 is in the thread take-out position. The yarn withdrawal device 24 remains in the yarn withdrawal position during the other full path of the seam formation. Alternatively, the yarn withdrawal device 24 may be incremented by an increment that forms, in each case, an increment in the direction of the neutral position during another formation of the seam, a portion of the full path of the yarn withdrawal device between the yarn withdrawal position and the neutral position, As shown in FIG. Since this increment is small for every needle stitch, the thread path returns for each incremental motion process of the thread take-off device 24 and is smaller than the stitch length. As a result, the additional thread path provided through the bypass line of the upper thread 9 via the thread take-off device 24 moved to the thread take-out position has no other effect on the formation of the other seams, Is returned.

The operation of the thread take-off device 24 starts at the 0 ° arm shaft position according to Fig. 2 together with the free end 36 of the upper thread 9, that is to say released. In this position, the two-ply product 34 to be sewn is inserted. The state information "start of seam" is stored in the control device 6. [ Proceeding from the position according to Fig. 2, the sewing of the seam in the product 34 to be sewn starts as shown in Fig. Only in the first order and after that, the yarn draw-out device 24 is moved to the yarn withdrawing position as described above. According to the above description, the movement of the yarn draw-out device 24 from the neutral position to the yarn withdrawal position is made in the second needle sweat. In all succeeding needle swabs, the thread take-out device 24 is continuously left in the thread take-out position. The free end 36 of the upper thread 9 is pulled back to the thread lever 18 through the product 34 to be sewn so that the thread take-off device 24 operates from the arm shaft position of 325 degrees to the thread take-out position. Alternatively, the movement of the yarn draw-out device 24 from the neutral position to the yarn withdrawal position may be made in the first needle sweat, in the third needle sweat or in a much later needle sweat.

After the first reciprocation process of the yarn withdrawal device 24 from the neutral position to the yarn withdrawal position, the state information "beginning of seam" is changed from control device 6 to "seam ". A new transition to "start of seam" is made by the control device 6 after the actual cut-off process. This status information is required during another sewing process. The yarn draw-out device 24 is operated only when there is the status information "start of seam ". At the end of the sewing process and optionally after the yarn is cut off, the yarn withdrawal device 24 returns to the neutral position. This is also done in increments during seam formation, as previously described.

The length of the free end 36 protruding above the product 34 to be sewn can be predetermined by the angular position of the extending arm 25 at the yarn withdrawal position. In the control device 6, particularly when the extension arm 25 is driven by a stepping motor, a plurality of start chamber lengths can be preselected. Depending on the preselected starting chamber length, the angular position of the elongate arm 25 actuated by the control device 6 results in the withdrawal position. The yarn withdrawal length corresponding to the starting yarn length can alternatively be adjusted by mechanical stops for the elongate arms 25. [

The entire sequence of the first needle-stitch at the beginning of the seam during the reciprocating motion of the yarn draw-out device 24 from the neutral position to the yarn withdrawing position takes place at a fixed rotating arm shaft speed reduced compared to the rotating operation speed of the arm shaft 5 . This reduced rotational arm shaft speed is also predetermined by the control device 6. [

In other words, the method for sewing the beginning of the seam is detailed below: First, an upper thread loop is formed. The upper thread loop is then caught by the hook tip of the hook 10 at the rotary gripping position of the hook tip. The upper thread 9 is then rotated about the hook end of the hook 10 about the hook housing 10 of about 240 to 250 degrees, particularly 245 degrees, until the reverse rotational position opposite the rotary gripping position is reached, And is pulled out to the hook tip of the hook 10. From the rotational gripping position, the hook tip of the hook 10 is rotated by at least half a revolution around the hook housing of the hook 10, that is, rotated to the reverse rotation position. After reaching the reverse rotation position of the hook tip of the hook 10, the thread take-out device 24 is moved from the neutral position to the thread take-out position.

The actual path difference caused by the motion of the elongated arm 25 between the neutral position and the yarn withdrawal position can be predetermined according to the thickness of the product 34 to be sewn. The thickness of the product 34 to be sewn may be adjusted by the user or measured by a thickness sensor not shown in the figures. The control device 6 may have a signal connection to the thickness sensor of the product to be sewn in order to process the thickness measurement of the product to be sewn and send the desired yarn path difference value to the yarn drawer 24. [

Since the main tensioner 22 is ventilated for the yarn cutoff process at the end of the sewing process, there is no yarn tensile force at the position of the main tensioner 22. During the sewing process, the main tensioner 22 produces the required tensile force required for sewing. The main tensioner 22 is transferred to the thread clamping position so that the upper thread 9 is reliably pulled back from the free end 36. In this state, The thread clamping function of the main tensioner 22 can be used in a sewing job where the upper thread 9 is susceptible to high friction in the product to be sewn.

In Fig. 8 to Fig. 12, another embodiment of the upper thread guide of the sewing machine will be described below, which can be used in place of the upper thread guide described above with reference to Figs. 1 to 7. The elements and functions described above with reference to Figs. 1 to 7 have the same reference numerals and will not be discussed in detail again.

The upper thread tensioning device 38 of the embodiment according to Figs. 8 to 12 has two upper thread tensioning units 39 and 40 that are configured together as a main tensioner. The upper thread tensioning unit 40, which is one of the two upper thread tensioning units, is disposed in the upper thread path between the thread lever 18 and the thread take- This upper thread tensioning unit 40 is additionally provided in comparison with the main tensioning device 21 of the embodiment according to Figs. The upper thread tensioning unit 39, which is another one of the two upper thread tensioning units, is disposed at the position where the upper thread tensioning unit 22 is disposed according to Figs. 1 to 7.

The free lever 36 of the upper thread 9 is pulled out from below through the product 34 to be sewn and then the thread lever 18 is pulled out of the upper thread 9 in the product 34 to be sewn due to the use of the thread take- The sewing of the beginning of the seam withdrawing back in principle takes place in principle in the embodiment according to Figs. 8 to 12, as in the embodiment according to Figs. 1 to 7, precisely. Immediately prior to the movement of the yarn withdrawal device 24 from the neutral position to the yarn withdrawal position at the 325 ° arm shaft position, the upper thread tensioning unit 40 moves from the normal tensile force position between the yarn withdrawal device 24 and the yarn lever 18 Lt; RTI ID = 0.0 > tensile < / RTI > Thereafter, the upper thread 9 is subjected to a residual thread tensile force by the upper thread tension unit 40 between the thread take-out unit 24 and the thread lever 18, and this residual thread tensile force is smaller than the upper thread normal tension. The reason for this is that the thread take-out device 24 withdraws the upper thread from the thread lever 18 backward and does not withdraw it from the upper thread supply portion as it does not wish. The residual thread tension is set such that the upper thread 9 is moved between the thread take-out position and the neutral position of the thread take-out device 24 in order to prevent the upper thread 9 from being accelerated by the thread take- ) Due to the difference in thread path of the upper thread (9). After the movement of the thread take-out device 24 to the thread take-out position, the upper thread tensioning device 40 is operated again.

Otherwise, the operation of the sewing machine having the upper thread guide according to Figs. 8 to 12 coincides with that of the sewing machine according to Figs. 1 to 7 as described above. The cross section of the two-ply product 34 to be sewn according to Fig. 4 also applies to the embodiment of the sewing machine having the upper thread guide according to Figs. 8 to 12. Fig.

1 Sewing machine
9 Top thread
10 Hook
14 Upper thread clamp
18 thread levers
24 yarn withdrawal device
25 extended arm
27 thread eyelet

Claims

The housings (2, 3, 4),
A supply part for the upper thread 9,
The needle bar 7 having the sewing needle 8 for guiding the upper thread 9 through the product 34 to be sewn, in this case the sewing needle 8 vertically moves up and down vertically and moves between the bottom dead point and the top dead point Lt; / RTI &
A hook 10 for holding the upper thread 9 during formation of a needle sweat,
A thread lever 18 for pulling out the loop of the upper thread 9,
Between the hook 10 and the seal lever 18, an operable upper thread clamp 14 in the supply thread upper thread path,
And an upper thread tensioning device (21; 38) in the upper thread path of the supply part before the upper thread (9) in the operating state receives a certain thread tension by the thread lever (18)
A neutral position in which the upper thread 9 takes a first thread path between the thread lever 18 and the upper thread tension unit 22 (39)
A yarn withdrawing position in which the upper thread 9 is longer than the first thread path by a distance equal to the actual thread path and takes a second thread path between the thread lever 18 and the upper thread tensioning units 22 and 39,
The thread take-off device 24 in the upper thread path between the upper thread tensioning unit 22 (39) and the thread lever 18 of the upper thread tensioning device 21 (38), which can be moved in a controlled manner between the two positions, / RTI >
Characterized in that the thread take-off device (24) has a pivotable extension arm (25) and a threaded eyelet (27) is arranged at the end of an extension arm which can pivot in a direction perpendicular to the thread path .

The sewing machine according to claim 1, wherein the threaded eyelet (27) in the neutral position is disposed in an upper thread path between two thread guide eyelets (28) fixed to the housing.

The sewing machine according to claim 1, characterized by one upper thread clamp (14) in the upper thread path of the feeder side.

The sewing machine according to claim 1, wherein the upper thread tensioning device (21) is disposed only in the thread path between the thread take-out device (24) and the upper thread supply part.

The apparatus of claim 1, wherein the upper thread tensioning device (38) has a plurality of upper thread tensioning units (39,40), one of the upper thread tensioning units (40) is between the thread lever (18) Wherein the sewing machine is arranged in a yarn path.

delete