KR102557765B1 - Method to produce a starting segment of an upper thread in a seam having a short target protrusion of the starting segment with respect to the seam as well as assembly provided to perform such method - Google Patents

Abstract

In order to form a seaming-start upper thread having a target-seam width of up to 10 mm, first, the upper thread area is transferred through the sewing material 15 from the upper side of the sewing material to the lower side of the sewing material using a needle. Subsequently, the upper thread-start region 13a is taken out with the looper 19 until the entire upper thread-start region 13a is below the sewing material. The upper thread-start area 13a is caught and guided by the upper thread catcher 40 . The upper thread-starting area 13a is then treated, so that the seam width is achieved.

Description

A method of forming a seam-start upper thread having a short target-seam width and an assembly for implementing the method as well as assembly provided to perform such method}

The present invention relates to a method for forming a seam-starting upper thread having a target-seam width of up to 10 mm. The invention also relates to an assembly for carrying out such a method and a sewing machine having an assembly of this kind.

Sewing machines are known from EP 1 847 641 B1, DE 102 34 251 C1, DE 10 2006 019 193 A1 and DE 101 23 075 C1.

An object of the present invention is to provide a method for obtaining a seaming-start upper thread having a desired short target-seam width. Using this method, when sewing a sewing material, it is possible to most certainly prevent the protruding thread from the side of the sewing material beyond the edge of the sewing material.

This problem is solved according to the invention with a method comprising the features set out in claim 1 .

According to the present invention, as is known, for example from DE 102 34 251 C1, it is not only possible to pull the upper thread-start region down through the sewing material at the beginning of seaming formation, but rather also to achieve a desired small target-seaming width. It can be seen that it is also possible to guide and process the upper thread-start area being pulled down. The resulting target-seam width may be at most 9 mm, at most 8 mm, at most 7 mm, or even smaller.

Since the upper thread-start area according to claim 2 is cut off, the target-seam upper thread width is directly formed to be small.

What is ensured by gripping and fixing the upper thread-start region according to claim 3 is that the longer upper thread-start region is positioned along the seam through control at the beginning of the formation of the seam in the execution of the first stitch, in which case The beginning of the upper thread-start region having the maximum length of the stitch length is that which projects above the seam. If a maximum stitch length of 10 mm is guaranteed in this seam-start region, this automatically results in achieving the desired small target-seam width of the upper thread. The upper thread catcher clamp may be disposed adjacent to an upper thread catcher. The upper thread catcher can be used as a looper of the sewing machine at the same time, and can also be a stitch forming tool. Alternatively, the upper thread catcher on the one hand and the looper on the other hand may be different machine-elements. The upper thread-catcher clamp may be formed through its own clamp unit, and in this case, the upper thread-start area is passed into the clamp unit through control by the upper thread catcher. This type of clamp unit can be formed directly on the upper thread catcher. As an alternative to this, the clamp may be formed through two parts that exist in the case of the sewing machine, and between them, the upper thread starting area is caught through the upper thread catcher and then guided as desired. These clamp-parts can be bobbin bobbins on the one hand and bobbin housings on the other hand.

According to claim 4, when the length of the upper thread-start region is set by the upper thread-guide clamp, the upper thread-start region is prevented from becoming too long undesirably. In addition, the upper thread-guide clamp guarantees that the upper thread-start area is actually taken out through the looper and the upper thread is pulled back from the upper thread flow between the sewing needle and the upper thread supply.

Avoided through smaller start-stitch lengths according to claim 5 , for example short one start stitch, two short start stitches or three short start stitches, the upper-start area is undesirable when guiding and processing. It is accompanied with the feeder, which, although not desired, may cause the upper thread to have an extension path between the sewing material and the exit from the stitch hole.

The adjustment of upper thread pull or thread guide via the thread tension device according to claim 6 ensures an adjustable setting of thread guide and treatment, which can be used to adapt to different material qualities and/or different thread qualities, for example. there is. Adjustment of the thread tension device may depend on the implementation or action of the upper thread catcher clamp. In this way, the interaction between the thread tension device and the upper thread-catcher clamp can be optimized.

The advantages of the assembly according to claim 7 correspond to those previously described with reference to the forming method according to the invention. The looper and upper thread catcher may be the same part. Alternatively, the looper and upper thread catcher may be formed from separate elements.

The upper thread knife according to claim 8 enables safe cutting of the held upper thread-starting area. The upper thread knife may be formed as a separate element from another thread drawing knife for thread cutting at the end of the seam. Alternatively, the upper thread knife can be implemented as a thread drawing knife for thread cutting at the seam end at the same time.

When the upper thread catcher according to claim 9 and in particular the upper thread knife are installed, the upper thread-start area is guided independently of the motion of the feeder and can be cut particularly short.

The advantages of the upper thread catcher clamp according to claim 10 correspond to those already described in connection with the catcher clamp step of the forming method. The upper thread catcher clamp may be disposed adjacent to the upper thread catcher. In this case, the upper thread-catcher clamp may likewise be installed in the carrier for the sewing material-transporter. The upper thread-catcher clamp may be formed through interaction between the bobbin and the bobbin housing of the sewing machine.

Arranging the upper thread catcher clamp according to claim 11 simplifies the guidance of the upper thread start area through control.

The advantages of the upper thread-catcher clamp according to claim 12 correspond to those already described above with the guide clamp step in the forming method.

Correspondingly applies to the yarn tensioning device according to claim 13.

What can be especially avoided through proper setting through the upper thread-guide clamp and/or thread tension device is that the pulled-out upper thread-start region is long and knotted with the lower thread when it is pulled out.

The suction device according to claim 14 prevents undesired cut yarn residues from accumulating in the area of the sewing machine.

The advantages of the sewing machine according to claim 15 correspond to those already described in relation to the forming method and sewing assembly.

Embodiments of the present invention are detailed below using figures.

1 is a front view of a double stitch sewing machine.
2 is a schematic view schematically showing a stitch formation area of the sewing machine.
FIG. 3 is an enlarged plan view of one area of the sewing machine seen in the direction of arrow III in FIG. 1. In this case, the stitch forming tools are shown at loop stroke positions when the upper thread loop is caught through the looper tip.
Fig. 4 is a view similar to Fig. 3 of the stitch forming tool in a position subsequent to the position according to Fig. 3, in which case the looper tip has completely taken out the free end of the upper thread start from the sewing material.
Fig. 5 is a view similar to Fig. 3 and related to a position following the position according to Fig. 4, in which case the free end of the upper thread is cut through the cooperation of the upper thread-counter knife and the upper thread catcher;
6 is a schematic plan view of a seam sewn using the sewing assembly according to FIGS. 3 to 5, wherein a seam-start upper thread having a set target-seam width is formed.
Figure 7 is a view similar to Figures 3 to 5, showing another embodiment for guiding the upper thread-start area caught through control, wherein the upper thread-start area is a bobbin cover and a bobbin housing of the lower thread bobbin fixed between
8 is a plan view schematically showing a seam sewn using the sewing assembly according to FIG. 7, and a seam-start upper thread having a set target-seam width is formed.

The double stitch sewing machine 1 has a pedestal 2, which includes a stand 3 extending upwardly from the pedestal and a bent arm 4. The arm ends in a head (5). An arm shaft 6 is rotatably supported in the arm 4 . The arm shaft drives the crank drive (7) and thread lever (8) in the head (5). On the driving side, the crank drive (7) is connected to the needle bar (9) supported axially in the head (5). It has a needle 10 at its lower end. The needle 10 can move up and down on the vertical axis 11 through the crank drive 7.

An xyz-Cartesian coordinate system is used in the following to simplify the description of the positional relationship. The vertical axis 11 extends along the z-direction of the coordinate system. The x direction extends perpendicularly to the drawing plane of FIG. 1 and inwardly and is parallel to the sewing direction of the sewing machine 1 . The y direction extends leftward in FIG. 1 .

The needle thread 13 provided starting from the bobbin 12 and passing through the thread tension device and the thread lever 8 is guided into the needle hole of the needle 10, in which case this needle thread is also called upper thread. The needle thread 13 has an upper thread-start free area 13a. The pedestal 2 supports a support plate 14 fixed with screws, and a sewing material 15 is placed on the support plate. The support plate 14 is formed with a recess for the passage of the lower material feeder 17 . This material feeder has a stitch hole 18 through which needle 10 can pass. The material feeder 17 is connected on the driving side with a push-and-stroke drive arranged under the pedestal 2 in a conventional manner.

A looper 19 is located under the support plate 14, and in this case, the looper includes a looper body 20 and a looper tip 21. In this looper body 20, a pot-shaped bobbin housing 22 for accommodating a looper thread supply in the form of a bobbin 22a is supported. The upper edge contours of the bobbin housing 22 on the one hand and of the bobbin 22a on the other hand are indicated by dotted lines in the schematic view according to FIG. 2 . The looper thread is also called a lower thread.

The looper 19 may rotate about a vertical looper shaft 23 extending in the z direction. The sewing mode rotation direction 24 of the looper body 20 proceeds clockwise around the looper shaft 23 in FIG. 3 . The looper body 20 is fixedly connected to the shaft 25, and the shaft extends coaxially with the looper shaft 23. The shaft 25 is rotatably supported in a bearing block 26 screwed to the pedestal 2 . A drive shaft 27 is supported therein and connected to a gear drive arranged inside the bearing block 26. Since the gear drive has a conversion ratio of 1:2, when the drive shaft 27 rotates once, the looper body 20 located on the shaft 25 rotates twice. For driving, the drive shaft 27 is connected to the arm shaft 6 by means of a belt drive 28 .

A thread pulling knife 29, known for example from EP 1 847 641 B1, is used to cut the needle thread 13 and the looper thread at the seam end.

In order to fix and transfer the sewing material 15, the sewing machine 1 additionally has a presser foot 30 and an upper conveyor 31, and the upper conveyor is together with a lower material feeder 17 for conveying the sewing material. It works.

2 also shows the flow of the upper thread 13 from the bobbin 12 to the upper thread-start area 13a. The upper thread 13 starts from the bobbin 12 and is guided toward the needle 10 through the thread tension device 32, the thread lever 8, and the upper thread guide clamp 33.

The upper thread-guide clamp 33 has a spring washer 34 fixed to a guide bar 35. To fix the upper thread 13, the spring washer 34 is pulled toward the housing fixed abutment 37 of the upper thread-guide clamp 33 by the compression spring 36. An electromagnet 38 schematically shown in FIG. 2 is installed on the shift 37, and although not shown in detail, the electromagnet is controlled by the central control device 39 of the sewing machine 1.

3 to 5 below, an embodiment of a sewing machine assembly for forming a seaming-start yarn having a target-seaming width of up to 10 mm is shown.

The sewing machine-assembly has an upper thread catcher 40 for catching the upper thread 13. The upper thread catcher 40 has a catch eye 41 at its free end (compare Fig. 5), and the catch eye simultaneously serves as a movable upper thread knife. The free end of the upper thread catcher 40 is in the starting position shown in FIG. 3 under the lower material feeder 17, in which case the catch eye 41 is aligned with the stitch hole 18. The upper thread catcher 40 has a body 42 bent into an L shape and is supported by a pivot bearing 43. The pivot bearing 43 may be fixed to the housing or alternatively may be fixedly connected to the transport carrier 44 of the lower material feeder 17 . By means of the pivot bearing 43 the body 42 of the upper thread catcher 40 is movable about a pivot axis 45 between a starting position and an end-to-cut position according to FIG. 3 . 5 shows an intermediate position of the body 42 between the start position and the end-of-cut position. The pivot shafts 45 extend in parallel in the z direction. The upper thread catcher 40 is operated by a pneumatic drive, which is not shown in the drawings but is coupled to an actuating eye 46 in the body 42, in which case the actuating eye pivots in the main body 42. away from the shaft (45).

According to FIGS. 3 to 5 , a method for forming a seam-start upper thread having a target-seaming width of up to 10 mm is described below.

3 shows the stitch forming tool of the sewing machine 1 in the loop stroke position. The sewing needle 10 leaves its bottom dead center and moves up again in the direction of the positive z-axis, forming an upper thread loop 47. The looper tip 21 engages the upper thread loop 47 at the position according to FIG. 3 . The upper thread catcher 40 is in the starting position, and in this case, the upper thread loop 47 is formed under the catch eye 41 of the upper thread catcher 40 . The upper thread loop 47, along with the sewing needle 10, penetrates the sewing material 15 and represents an upper thread area conveyed from its upper side to its lower side.

The catch eyes 41 are disposed under the lower material feeder 17 at very narrow intervals. This gap is less than 1 mm.

The upper thread-starting free region 13a protrudes upward from the sewing material 15 at a position according to FIG. 3 .

FIG. 2 shows the rotational position of the looper immediately after the position according to FIG. 3 .

FIG. 4 shows the position of the stitch forming tool after looper rotation of 180° or more compared to FIG. 3 . The looper tip 21 completely pulls the upper thread-start area 13a passing through the sewing material 15 downward during rotation. In this case, the upper thread-start area 13a passes through the stitch hole 18 and the catch eye 41 downward. The upper thread 13 passes over the looper 19 and under the thread pulling knife 29 between the looper tip 21 and the stitch hole 18 and passes first through the catch eye 41 towards the sewing material from below and then It passes through the stitch hole 18 in the lower material feeder 17. The upper thread-start area 13a is taken out by the looper 19 until the entire upper thread-start area 13a is below the sewing material lower side.

Since the upper thread-catcher clamp 33 is closed while taking out the upper thread-start area 13a through the looper tip 21, the upper thread 13 moves from the upper thread supply to the upper thread-catcher clamp 33 on the flow of the upper thread. Cannot be pulled from the front, after pulling the upper thread-start area 13a through the looper tip 21, the upper thread-guide clamp 33 is opened.

FIG. 5 shows an intermediate position of the body 42 of the upper thread catcher 40 between the starting and cutting-end positions according to FIGS. 3 and 4 just before the cutting of the upper thread-start region 13a. When the main body 42 rotates, the upper thread catcher 40 holds the upper thread 13 for shortening the upper thread-start region 13a by the catch eye 41 . In the position according to FIG. 5 , the peripheral edge of the catch eye 41 acts together as an upper thread knife with the housing fixed counter knife 48 of the assembly to cut the upper thread 13 . In the position according to FIG. 5 the needle 10 leaves the stitch hole 18 upwards.

As a result of the cutting process, the upper thread 13 was obviously shortened. In the sewing material 15, the free end of the upper thread-starting region 13a is located at a seaming start portion having a length of up to 10 mm. The remaining length of the upper thread-start region 13a may be less than 10 mm, may be 9 mm, 8 mm or 7 mm, and may be even less.

Cutting the upper thread 13 from the counter knife 48 to the upper thread knife 41 is the final result of the guide of the upper thread-start area 13a held by the upper thread catcher 40, and the upper thread-start area 13a , resulting in a desired seaming width of the upper thread-start region 13a of up to 10 mm.

Now, the seam can be formed as a double bond seam under the division of the upper thread 13 and the lower thread, which is not shown in detail in FIGS. 1 to 5 . After that, the thread cutting process of the upper thread 13 and the lower thread at the end of the seam is performed with a thread pulling knife 29.

By means of the control device 39 the stitch length is shortened according to the sequence of Figs. 3 to 5 during the sewing process and especially during the cutting of the upper thread-start region 13a. This prevents unwanted relative motion between the lower stock feeder 17 and the upper thread-starting region 13a.

The drawing according to FIG. 6 shows a seam 48 made of the sewing assembly according to FIGS. 3 to 5 in the seam-start area. The sewing direction proceeds to the left along the x direction in FIG. 6 . Because of the upper thread area between the upper thread knife 41 and the counter knife 48, the upper thread-start region 13a is short at the beginning of the seam 48a, resulting in a maximum seaming width A of 10 mm.

Also, it is shown in FIG. 6 that the first both start-stitches (S ₁ , S ₂ ) are shortened compared to the next stitches (S ₃ ,...,S _n ).

Another embodiment of a sewing assembly for forming a seam-start upper thread having a target-seam width of up to 10 mm is described below using FIG. 7 . Elements corresponding to those already described in detail with reference to FIGS. 1 to 5 have the same reference numerals and are not described in detail again.

The assembly according to FIG. 7 has, in addition to the assembly according to FIGS. 1 to 5 , a stroke device 49 shown schematically in FIG. 6 . This stroke device 49 can also be implemented as a pneumatic cylinder. The stroke device 49 can be controlled by a central control device 39 . The stroke device 49 is disposed between the bottom of the bobbin housing 22 and the lower bottom wall of the bobbin 22a. Stroke movement of the bobbin 22a in relation to the bobbin housing 22 by means of the stroke device 49 can be achieved along a movement path 50, which is indicated in FIG. 2 . In the raised position of the bobbin 22a in relation to the bobbin housing 22, the cover wall 51 of the bobbin 22a extends 0.5 from the upper side of the bobbin housing 22 towards the edge over the bobbin compartment 52 opposite it. It protrudes more than mm, for example, more than 1 mm.

In order to controllably guide and process the upper thread-start area 13a caught using the looper tip 21 representing the upper thread catcher, a target-seam width of up to 10 mm is preferred, and the assembly according to FIG. 7 has the following works like:

In terms of forming the upper thread loops 47 and fixing them by means of the looper tip 21 , the assembly according to FIG. 7 first operates as previously described with respect to FIGS. 1 to 3 .

When the position corresponding to FIG. 3 is reached, the stroke device 49 is actuated so that the bobbin 22a protrudes over the upper edge of the bobbin housing 22 . Then, the looper tip 21 takes out the upper thread 13 and pulls the upper thread-start region 13a penetrating the sewing material 15 downward, which has been described above in relation to the practice according to FIGS. 1 to 5 It became. In the case of the embodiment according to FIG. 7 , the upper thread-start area 13a is formed over the bobbin housing 22 based on the width of the cover wall 51 of the bobbin 22a between the cover wall 51 and the bobbin housing 22. It can be located between, as shown in Figure 7. In that case, the upper thread 13 is located in the bobbin 22a in this area.

At the position of the looper tip 21 according to FIG. 7 or at the rotational position in which the looper tip 21 is advanced by about 45°, the stroke device 49 is brought over to the starting position, so that the bobbin 22a returns to the bobbin housing. (22) I go down to my normal position. Then, the upper thread-start region 13a is fixed between the bobbin 22a and the bobbin housing 22. After that, the upper thread-catcher clamp is formed through the bobbin 22a and the bobbin housing 22.

When the next stitch is formed after the position shown in FIG. 7 and the upper thread-start region 13a is fixed, the upper thread-start region 13a is pulled out step by step from the upper thread-catcher clamp as seaming proceeds, and the upper thread - The starting area 13a is wound by the lower thread like an upper thread area guided directly from above through the stitch hole 18 from the sewing material 15 and is knotted together when forming the seam. Then, the free start portion of the upper thread-start area 13a has a length in the range of one stitch length. If this stitch length is adjusted to a maximum of 10 mm, consequently a desired target-seam width of maximum 10 mm can be achieved through the upper thread-start region 13a.

8 shows a seam 48b made using the sewing assembly according to FIG. 7 . The upper thread-start region 13a is not separated from the seam 48b at the beginning of the seam 48b, but rather is located between stitches S _i and stitches S _{i +1} . The size of i depends on the length of the upper thread-starting region 13a pulled under the sewing material, in which case it is pulled out step by step from the fixed region between the bobbin 22a and the bobbin housing 22 during sewing. i may range between 4 and 10, for example. Even in the case of the shim 48b, the shim width A of the upper thread-start region 13a is 10 mm.

According to the modification of the sewing assembly, the upper thread-guide clamp 33 may be omitted. Through the adjustment of the thread tension applied to the upper thread 13 by the thread tension device 32, when pulling and/or guiding the upper thread-start region 13a, a desired ratio is obtained in the upper thread-start region 13a. It results from the length of the upper thread 13 pulled from the upper thread 13 and the length of the upper thread 13 pulled from the upper thread path in front of the sewing needle 10. The stronger the thread tension is adjusted, the larger the share of the length size pulled by the upper thread-start region 13a can be larger compared to the length size of the upper thread 13 used by the thread tension device 32.

Additionally, the sewing assembly has a suction device 53 schematically shown in FIG. 5 for sucking the upper thread area cut with the upper thread knife 41 . The suction device 53 is arranged adjacent to the cutting edge of the counter knife 48 . The suction device 53 is connected to a vacuum source.

Upper thread catcher 40 with catch eye 41 can be used in another variation of the sewing assembly for forming a start-to-seam upper thread having a target-seam width of up to 10 mm without a counter knife. Then, the upper thread catcher 40 works together with the upper thread catcher clamp according to the fixing part described above between the bobbin 22a and the bobbin housing 22. The upper thread catcher clamp may be disposed adjacent to the upper thread catcher 40 .

In this variant of the sewing assembly, the upper thread-start region 13a is not cut, but rather is guided through control and sewn to the seam-start region as already described with reference to FIGS. 7 and 8 above. In this sewing process, what is achieved by simultaneously moving the catch eye 41 in the +/-y direction for seam formation is that the upper thread starting area 13a moves the upper thread-catcher clamp to the right (-y direction). And since it is brought out toward the left side (+y direction) and placed in the stitch hole, it is always placed under each stitch and sewn underneath. In order to place the upper thread-start region 13a in the +/-y direction, the side of the stitch hole 18 guiding the upper thread-start region 13a during sewing of the start-seam region runs straight, that is, round It can be formed not to bend.

Claims (15)

As a method for forming a seam-start upper thread having a target-seaming width (A) of up to 10 mm,
- fixing the sewing material 15 with the presser foot 30;
- Transferring the upper thread area 47 from the upper side of the sewing material to the lower side of the sewing material using a sewing needle 10 penetrating the sewing material 15;
- Taking out the upper thread-start region 13a using a looper 19 until the entire upper thread-start region 13a is under the sewing material-lower side;
- A step of catching the upper thread-start area 13a taken out in advance by the looper 19 using the upper thread catcher 40;
- guiding the upper thread-start region (13a) with the upper thread catcher (40) and processing the upper thread-start region (13a), in order to consequently achieve the seam width (A);
here,
- the upper thread catcher 40,
- the presser foot 30 and
- the looper (19) is designed with different sewing machine-elements. According to claim 1,
A method characterized in that the upper thread-start region (13a) held by the upper thread knife (41) is cut off to form the seam width (A). According to claim 1,
A method characterized by fixing the upper thread-start region (13a) held using an upper thread-catcher clamp to form the seam width (A). According to claim 1,
The length of the upper thread-start region 13a is set by the upper thread-guide clamp 33 in front of the sewing needle 10 during the upper thread progress. According to claim 1,
The upper thread-start area 13a is guided through the stitch hole 18 of the sewing material-transporter 17 after conveying through the sewing material 15, and this forming method is prescribed-stitch at the time of seam formation. characterized in that it is carried out with a start-stitch length (S ₁ , S ₂ ) smaller than the length (S ₃ ). According to claim 1,
When taking out and/or guiding the upper thread-start area 13a, the desired ratio is
- the size of the length of the upper thread 13 pulled out from the upper thread-start area 13a;
- A method characterized by adjusting the thread tension device (32) in front of the sewing needle (10) during the progress of the upper thread so as to result from the size of the length of the upper thread (13) taken out in front of the sewing needle (10) during the progress of the upper thread. Assembly for carrying out the method according to any one of claims 1 to 6,
- a driven needle bar (9) for guiding the upper thread (13) and a sewing needle supported by it;
- Looper (19),
- an assembly having a thread catcher (40) for catching the upper thread (13). According to claim 7,
Assembly characterized by an upper thread knife (41) for cutting off the upper thread-start region (13a) held. According to claim 7,
Assembly characterized by a sewing material-feeder (17) in which the upper thread catcher (40) is installed on a carrier (44) for the sewing material-feeder (17). According to claim 8,
An assembly characterized by an upper thread-catcher clamp for fixing the upper thread-start area 13a that is caught. According to claim 10,
The assembly characterized in that the upper thread catcher clamp is disposed adjacent to the upper thread catcher (40). According to claim 7,
An assembly characterized by an upper thread-guide clamp (33) for setting the length of the upper thread-start region (13a) located in front of the sewing needle (10) on the upper thread flow. According to claim 7,
Assembly, characterized in that the thread tension device (32) in front of the sewing needle (10) can be adjusted during the upper thread progress. According to claim 8,
Assembly characterized by a suction device (53) for suctioning the cut upper thread area. A sewing machine comprising the assembly according to claim 7 .