EP3289132A1

EP3289132A1 - Multi-needle chain-stitch sewing machine

Info

Publication number: EP3289132A1
Application number: EP16727622.9A
Authority: EP
Inventors: Herbert Pfleger
Original assignee: Pfaff Industriesysteme und Maschinen GmbH
Current assignee: Pfaff Industriesysteme und Maschinen GmbH
Priority date: 2015-04-27
Filing date: 2016-04-26
Publication date: 2018-03-07
Anticipated expiration: 2036-04-26
Also published as: CN108026682B; DE102015005298A1; EP3289132B1; ES2904508T3; CN108026682A; PT3289132T; WO2016173708A1

Abstract

The invention is intended to enable a multi-needle chain-stitch sewing machine to produce in a single operation chain-stitch seams which run parallel to one another and are at a small distance from one another and in which the points of insertion of the needles in the seams are not offset from one another in relation to the longitudinal direction thereof. For this purpose, a multi-needle chain-stitch sewing machine is provided, comprising multiple needles (2) each guiding an upper thread (5), wherein the multiple needles are arranged respectively at a distance from one another along a straight-running line and can be moved synchronously in relation to one another, and the line is aligned at least substantially orthogonally in relation to the intended direction of advancement of a transporting mechanism for the material to be sewn, also comprising a thread guide (4) for the multiple upper threads, in order to guide each upper thread (5) from its thread supply (6) to the needle assigned to it, comprising multiple driven loopers (3), each guiding an underthread (25), wherein the loopers (3) are arranged at a distance from one another and can be moved synchronously in relation to one another, the movements of the loopers (3) and the needles (2) having the effect in each case that an upper thread (5) and an underthread (25) can be interwoven, in order in this way to produce simultaneously in the material to be sewn multiple seams running parallel to one another, with points of insertion of the needles arranged in the material to be sewn without being offset from one another in the direction of advancement, and a drive device, which has at least one motor and by which the movements of the needles and the loopers can be produced in a predetermined and coordinated way. According to the invention, such a chain-stitch sewing machine is to be provided with a thread tensioning means (10), for at least one of the upper threads (5), arranged in the region of the thread guide and provided in addition to a thread take-up (11), with which at least one of the upper threads can be provided with an additional thread tension in the region between the thread tensioning means (10) and the needle (2) assigned to the at least one upper thread (5).

Description

Multi-needle chain stitch sewing machine

The invention relates to a Mehrnadelkettenstichnähmaschine with a plurality for receiving each of a needle thread leading provided needles, wherein the plurality of needles along a straight line spaced from each other and are movable synchronously with each other, and the line is aligned at least substantially orthogonal to the intended feed direction of a Nähguttransports yarn guide for the plurality of upper yarns for guiding each upper yarn from its yarn supply to the needle associated therewith, with a plurality of driven grippers each for guiding a lower yarn, the grippers being spaced apart and movable synchronously with each other by the movements The gripper and the needles in each case an upper and a lower thread are entwined with each other, thereby at the same time several mutually parallel seams in the fabric, with in the feed direction of the fabric without offset each other in the fabric ang eordnete puncture sites of the needles to produce and at least one motor having drive means, with the puncturing movements of the needles and the gripper are generated in a predetermined manner and coordinated with each other.

Chainstitch seams are frequently used in the industrial production of sewing articles, among other things for seams of trousers, in particular jeans. Chainstitch seams, in contrast to lockstitch seams, have a higher elasticity, which is why chainstitch seams are often preferred for such applications. In jeans and other denim apparel, but not just denim, parallel and spaced seams are provided, such as double or triple seams.

For this purpose, two different types of machines have become known. One of the two machine types is called a crossline, the other machine type an inline chain stitch machine. The two types of machine differ mainly in the arrangement of the plurality of needles to each other and in relation to the intended feed direction of the material transport. In crossline machines, the multiple needles are arranged along a line that is in the fabric transport direction

CONFIRMATION COPY an angle other than 90 °, usually an acute angle; for example 45 °. Due to the offset of the needles relative to one another in relation to the intended material transport direction, this type of machine is particularly suitable for applications in which the needles can also have a small distance from one another with respect to the material transport direction. In this type of machine due to the principle-related offset of the stitch pattern tools in the seaming direction, the risk is low that threads are detected by adjacent stitch pattern tools and thus result in Nahtfehlbildungen.

In contrast, in the case of the in-line chain stitch sewing machines already mentioned, the needles are arranged in a line which runs perpendicular to the intended fabric transport direction. An offset of the needles and the other stitch pattern tools in fabric transport direction is not given here. In particular, the Oberfadenschiingen can here come into conflict with the or each adjacent grippers and in particular of these are covered. This results in errors in the stitch formation, which lead at least to optical errors, but usually to seams that do not fulfill their function. For this reason, the distance between adjacent needles of inline chain stitch sewing machines is limited. For the production of mutually parallel seams in one operation, which have a particularly small distance from each other, so far mainly crossline chain stitch sewing machines are used. However, these have the inherent disadvantage that the stitch points of the individual needles in the fabric and thus the seams are offset in their longitudinal direction to each other. This is often undesirable.

The invention is therefore based on the object to provide a sewing machine which is able to produce in a single operation parallel to each other running chain stitches which have a small distance from each other and in which the puncture sites of the seams with respect to their longitudinal direction have no offset from one another ,

This object is achieved by a Mehrnadelkettenstichnähmaschine with the features of claim 1. This should be a sewing machine of the in the aforementioned type, in particular, have a thread tightening means arranged in the area of the thread guide for at least one of the upper threads, with which at least one of the upper threads can be provided with an additional thread tension in the area between the thread tightening means and the needle associated with the at least one upper thread. An "additional thread tension" here can be understood as meaning a thread tension portion which, due to the action of the thread tightening means, at least temporarily results on the thread or threads and which adds up to a thread tension possibly present even without such thread tightening means.

In previous Mehrnadelkettenstichnähmaschinen the thread guide was usually for each thread with a thread brake and a thread take-up lever (commonly referred to as a thread feeder) provided that keep the upper thread under tension, provide the respective needle sufficient thread supply available and the thread of the thread loop with increasing needle movement Retract to a limited extent between the needle and the thread take-up lever after passing through the lower trough. According to the invention, a separate Fadenanzugsmittel is now preferably provided in addition to the thread take-up and preferably at a different location than that of the take-up, in the course of the upper thread, the respective upper thread passive or active at a certain time is tightened. With the suit of at least one upper thread, preferably all upper threads, at least temporarily an additional clamping force can be applied to the respective upper thread. The problem is also solved by method claim 16.

With these measures according to the invention, even with a significant reduction in the needle spacings of multi-needle in-line chain stitch sewing machines, functionally reliable and simultaneously a plurality of chain stitch seams arranged close to one another can be formed. This is true even for the so-called "Ketteln" in which, for example, at the end of a seam formation without stitching chainstitch seams are formed.With the lack of resistance for the upper threads through the fabric is the seaming of closely spaced chain stitches here particularly critical and error-prone has the measures according to the invention lead to safe even under these conditions Seams without seaming tools of juxtaposed seams capture threads from other than their own seams.

In connection with the present inventions, therefore, significantly smaller needle spacings of adjacent needles of inline multi-needle chain stitch sewing machines can be provided than hitherto. These needle spacings may be selected from a range of 4.4 mm to 2.6 mm, preferably from 4.2 mm to 2.8 mm, and more preferably from a range of 3.8 mm to 3.0 mm.

In an advantageous embodiment of the invention, the at least one thread tightening means may preferably be arranged between the thread brake and the thread take-up lever (thread take-up). At this point, the intended Fadenanzug can perform particularly effective and reliable.

A particularly advantageous embodiment of the invention can provide that only one common thread tightening means is provided for the upper threads of a plurality of needles, preferably for all needles. The this only one Fadenanzugsmittel associated with a plurality of upper thread should be located in an area of action of Fadenanzugsmittel or out, so that the Fadenanzugsmittel can act on the upper threads for a thread suit. Preferably, the plurality of upper threads are passed through the only one Fadenanzugsmittel. With this embodiment of the invention, the thread suit can be realized in a particularly economical manner.

In a further preferred embodiment of the invention, the thread tightening means may be passively movable to exert a force on the at least one upper thread. The design as a passively moving element complex drives for the Fadenanzugsmittel can be avoided. In this advantageous embodiment of the invention, the existing in the upper threads thread tension can be used to make different thread suits in different Stichbildephasen. In addition, this can be done with little effort an automatically performed reset the Fadenanzugsmittels. Furthermore, it is preferred that the Fadenanzugsmittel is designed as a mechanical spring element, or as a pneumatically acting element or as a cam-controlled element which is movably coupled to a drive device of the sewing machine.

It has also been found to be particularly advantageous that during a Stichbildezyklus, the Fadenanzugsmittel a - with respect to the height of the force exerted on at least one upper thread - variable force provides. This makes it possible, in particular, to exert a force adapted to the upper threads for the respective stitch formation phase and to generate particularly suitable force, in order to generate thread tensiones which are as suitable as possible in the upper threads and which can serve for controlled needle thread loop formation of each needle and / or for controlled entanglement between a respective upper thread and lower thread ,

Thus, it has proven to be advantageous if the thread tightening agent during a stitch forming phase, ie from the top dead center of the needles to the top dead center by the needles, at least two, preferably at least three, at least local maximum values exerted by the Fadenanzugsmittel on the at least one upper thread Strength, goes through. These multiple local maximums can be different sizes or the same size. Likewise, it can advantageously be provided that the thread tightening means repeatedly reaches at least local minimum values of the force exerted by the thread tightening means on the at least one upper thread during a stitch forming phase. These minimum values may also have different values or be the same size. This makes it possible, at least for certain points in time or phases of stitch formation or seam formation to adapt the force with which the thread tightening agent acts on at least one, preferably on all upper threads. It is thereby possible in particular to then apply an increased force to one or more upper threads in comparison to other times when the needles are at least approximately in one of the two dead centers of their movement, ie in the upper or in the lower dead center. At bottom dead center, the needles begin to form their respective upper thread loop by their subsequent upward movement and release. To prevent too large loops form, in particular a too large Have expansion in the direction of adjacent grippers, an increased Fadenanzugskraft may have a favorable effect on the upper threads at these times.

At the top dead center stage of the needles, a new stitching operation begins, with the loops formed in the immediately preceding stitching operation still resting on the grippers, and the grippers beginning their backward movement, during which the previously formed needle thread loops are released by the grippers due to the backward movement. In order for these Oberfadenschiingen controlled and can be released as not too large loops, a thread tightening can affect about the beginning of the gripper backward movement beneficial. In particular, together with the subsequent downward movement of the needle and the subsequent Nähguttransport, which also contribute to the streamlining of the gripper located Oberfadenschiingen, thus the Oberfadenschiingen can be kept taut to the intended jump of the grippers and thus small enough. Since the loops are thus in the backward movement of the gripper largely tight against their grippers, the loops are released to the predetermined phases and at least largely with a predetermined geometric shape. In a further preferred embodiment of the invention, the force exerted by the thread tightening means on one or more upper threads can then have at least local minimum values when the needles are between their upper and lower dead centers. The minimum values of the thread tightening means can be provided in particular when the needles penetrate into the sewing material and / or leave the sewing material again. During the downward movement of the respective needle can be provided during the penetration of the needle into the fabric by opening a yarn brake for the respective upper thread, a large supply of thread, which should not be reduced by the Fadenanzugsmittel as possible. During the upward movement of the respective needle with the upper thread looping occurs, which is not prevented by the thread tightening means due to excessive thread tensions, but should be controlled by a low action of Fadenanzugsmittel to avoid too large Oberfadenschiingen. In order to further increase the reliability of the chain stitch formation of a multi-needle chain stitching machine according to claim 1, it can further be provided that the loop stroke is reduced in comparison to previously known loop stroke values. It has proven to be advantageous if the looping stroke has a value from a range of 4 mm to 2.5 mm and preferably from a range of 3.5 mm to 2.7 mm. In this case, the distance between a bottom dead center of the respective needle and the position along the longitudinal axis of the needle can be understood as a "ski stroke", at which the gripper intersects the needle longitudinal axis during its movement. The shortening of the ski stroke leads to a reduction of the needle thread loop formed by the needle and thus to a reduction in the risk that adjacent grippers capture the needle thread loop of a needle.

In the same way, a reduced compared to previous movement lengths length of a spreader evasion movement support the measures according to claim 1, in order to achieve a secure stitch formation despite a small needle spacing. It has proven to be advantageous in this case if the spreader deflection movement has a length from a range of preferably 4.5 mm to 4.7 mm.

Each of the grippers may be arranged on a rotary shaft, with which the respective gripper performs a driven alternating pivoting movement. The eccentricity generating the alternating pivoting movement can preferably be reduced in embodiments according to the invention in comparison to otherwise usual eccentricities for driving the pivoting movement of the grippers. In the previously customary smallest needle spacing of 4.8 mm, the eccentricity is approximately 4.9 mm. Now, for example, values from a range of 4.0 mm to 4.6 mm, preferably 4.4 mm, may be provided. As a result, shorter pivoting paths of the gripper can be achieved. As a result, the loop taken up by the gripper is not overstretched and thus an intake of the upper thread is improved.

Further preferred embodiments of the invention will become apparent from the claims, the description and the drawings. The invention will be explained in more detail with reference to embodiments shown purely schematically in the figures, in which:

Fig. 1 shows a Mehrnadelkettenstichnähmaschine invention in one

Front view, which has an inline needle assembly and is provided with a Fadenanzugsmittel;

2 shows a Mehrnadelkettenstichnähmschine according to the invention according to the

Representation of Figure 1 in another stitch formation phase.

Fig. 3 shows a Mehrnadelkettenstichnähmschine invention according to the

Representation of Figure 1 in another stitch formation phase.

4 shows a multi-needle chain stitch sewing machine according to the invention according to FIG

Representation of Figure 1 in yet another stitch formation phase.

5 is a perspective cutaway view of the stitch pattern tools of the sewing machine of FIG. 1 in which the needles are approximately at their bottom dead center;

FIG. 6 shows the stitch pattern tools from FIG. 5, which are moving upward from FIG. 5; FIG.

FIG. 7 shows the stitch pattern tools from FIG. 5, which are moving upward from FIG. 5; FIG.

FIG. 8 shows the stitch pattern tools according to FIG. 5, which are approximately in a top dead center; FIG.

FIG. 9 shows the stitch pattern tools according to FIG. 8, which are descending from FIG. 8; FIG. 10 shows the stitch pattern tools according to FIG. 8, which are in a further phase of the downward movement starting from FIG. 9;

Fig. 1 1 An embodiment of a trained as a mechanical spring

Thread take-up means;

12 is a diagram in which a position of a needle tip over time is plotted in a graph and a tension force exerted on at least one upper thread by the thread tightening means in a second graph;

13 shows a perspective illustration of an eccentric drive of the gripper driven by a machine main shaft.

In Fig. 1, a multi-needle chain stitching machine 1 according to the invention is shown, which has a partially open housing shown with an upper part 1 a and a lower part 1 b. The housing 1 has in the front view in approximately a tilted by 90 ° U-shape. In the upper part 1a of the housing 1 is in particular a drive unit to drive a plurality of synchronously movable needles 2. The needles 2 are arranged in a common needle holder, which in turn is attached to a needle bar. The needle bar is operatively connected to the drive unit in the upper part 1a of the housing, so that a drive movement leads to an oscillating rectilinear up and down movement of the needle bar. In other embodiments, each needle 2 could also be attached to its own and each associated needle bar.

In the lower part 1 b of the housing 1, a further drive unit is provided, which is provided for also synchronous drive of grippers 3. Both the grippers 3 and the needles 2 belong to stitch forming tools of the multi-needle chain stitching machine. The two drive units for the needles 2 and the grippers 3 can, as is known per se, have a common motor which drives an arm shaft, from which in turn drive movements are provided and transmitted for each of the two drive units. The basic construction of the two drive units can be carried out in accordance with previously known multi-needle chain stitches. be built sewing machines. In other embodiments, the needles and the grippers could also be driven by a plurality of separate motors.

In the area of the front side of the upper part 1a, a thread guide 4 for upper threads is provided, with which for each needle 2 an upper thread 5 is guided by a thread supply 6 of the respective upper thread 5 to the corresponding needle 2. The thread guide 4 has, seen in the feed direction of the upper threads 5, for each upper thread 5 each an adjustable and only this upper thread associated yarn brake 7, through which the respective upper thread 2 is guided. The upper threads 5 are then then passed together through a guide 8. From here, the upper threads 5 come together to a thread tightening agent 10 and are passed through the Fadenanzugsmittel 10. In the further course, the upper threads 5 are again guided together by only one thread feeder 11. Subsequently, each upper thread 5 reaches its needle 2 and is performed there by the respective Nadelöhr. Each upper thread 5, together with the needle 2, performs its oscillating movement and in each case forms a needle thread loop required for the chain stitch seam formation in each movement cycle.

In the two illustrations of FIG. 11, a possible embodiment for a thread tightening means 10 is shown. Here, the thread tightening means 10 is formed as Fadenanzugsfedereinrichtung. This has a carrier 14, with the Fadenanzugsmittel 10 can be attached to the upper part 1a of the housing of the sewing machine and carries the leadership of the thread and a coil spring 15. The coil spring 15 is pushed onto a shaft of the carrier 14 and arranged thereon. A front end 15a of the coil spring 15 is fixed in place. A housing-side end of the coil spring is formed as a bracket 15b.

The arranged in the lower part 1 b of the housing a plurality of grippers 3 are arranged together on a gripper carrier 16, which in turn is driven by the drive unit in the lower part 1 b of the housing. This drive movement leads to a common and synchronous alternating tilting or pivoting movement of all grippers 3. The present in the same number as the needles 2 gripper 3 can hereby move between two end positions along a predetermined curved path back and forth. The curved or curved path of the gripper 3 may be, for example, a circular arc or an elliptical arc. As shown in FIG. 13, the grippers 3 are driven by means of an eccentric drive 17 which, in the case of the embodiment, again receives its rotary drive movement from the arm shaft. The eccentric drive 7 includes a rotatably driven by the arm shaft not shown shaft 18 on which an eccentric 19 is arranged. The eccentric 19 acts in the manner of a roller or cam drive and causes the alternating tilting movement of the gripper carrier 16. About the size of the eccentricity E, the size of the pivot angle of the gripper 3 is determined in their alternating pivoting movement. Compared to the size of previous eccentric drives for grippers a lower eccentricity is provided in the embodiment, namely 4.4 mm.

The plurality of identically designed grippers 3 each have approximately by themselves an approximately 90 ° tilted U-shape. Each gripper is attached to a gripper carrier 16 with the lower leg 3a of the tilted U-shape. Each of the gripper 3 has an upper leg 3b, which is provided from its rear end 22 to its gripper tip 23 with a recess 24 which for receiving and carrying the respective gripper 3 associated only a lower thread 25 through the upper leg 3b to is provided to the gripper tip 23. In the region of its free end, each gripper 3 runs approximately conically towards its gripper tip 23. The lower threads 25 coming from a lower thread supply are guided individually and in each case through one of the recesses 27 of a lower thread separating aid 28. From here, each lower thread passes into the region of the connecting leg 3 c of the U-shape of the respective gripper 3 and is introduced here into the inlet opening of the recess 24 formed as a passage. The lower thread 25 then exits in the region of an upper side of the hook tip 23 upwards and is led away upwards to the underside of the sewing material, not shown. In the exemplary embodiment with three needles 2 a total of three grippers 3 are provided, which are aligned parallel to each other. In other embodiments, a different number of grippers 3 may be present, wherein the number of grippers 3 should always correspond to the number of provided needles 2. In particular, a number of grippers from a range of 2 to 10 can be provided be. As well as adjacent needles 2, mutually adjacent grippers 3 preferably have the same distance from one another, preferably the same distance as the respective needles 2 assigned to the grippers 3. In the exemplary embodiment, adjacent gripper tips are 3.2 mm apart. Likewise, longitudinal axes of adjacent needles 2, preferably all spaced apart needles 2, each provided with a distance of 3.2 mm. The needles 2 are arranged along a straight line which is cut by each of the longitudinal axes of the needles 2 and to which the longitudinal axes are perpendicular. The line also runs perpendicular to the material transport direction. In the illustration of FIG. 1, the line is in the drawing plane of FIG. 1 or parallel to this drawing plane. The Nähguttransportrichtung is, however, aligned perpendicular to the plane of Fig. 1. In the area between the two legs, a needle guard 35 is mounted on the gripper carrier 16. This has a plurality of spaced-apart struts 36 which are arranged and aligned so that they represent a guide for the needles 2. If needles 2, for example, due to particularly stiff material, show a tendency to bend and deviate from their desired path, this deviation is limited by the struts 36 and the needles forced to comply at least approximately their desired orientation. In this way it is also ensured that the position of the Oberfadenschiingen 37 each in the range of the respective upper thread loop 37 associated with a gripper 3 and thus each Oberfadenschlinge 37 can be detected by their respective gripper 3.

Finally, in the region of the gripper 3, a carrier 38 for a plurality of spreader elements. In the embodiment discussed here, the spreader elements may be formed as spreader pins 39. With each spreader pin 39, the respective bobbin thread 25 of the respective spreader pin 39 associated with a lower thread 25 is detected at a certain time of stitch formation, to deflect this laterally by a Spreizerausweichbewegung predetermined length and direction. The spreader escape movement preferably occurs in a direction transverse to the needle movement. FIGS. 5 to 10 show the processes in stitch formation in the area of stitch pattern tools. For the discussion of the processes in stitch formation and seam formation, reference will also be made below to FIGS. 1 to 4, in particular in order to present the thread tightening means 10 acting on the respective upper thread 5 and designed as thread take-up spring and its function. In Fig. 5, the three needles 2 and the corresponding thereto three grippers 3 are shown. Each needle 2 carries a needle thread 5 which is passed through the respective Nadelöhr and each of the grippers 3 each carries a lower thread 25 which is passed through the upper leg 3b of each gripper. In the illustration of Fig. 5, the synchronously moving needle 2 are in the range of their bottom dead center and begin their reversal of direction of movement towards its top dead center. The three grippers 3 are on their way to their final position with their gripper tips in front of the needles 2 and are arranged at this time of stitch formation phase before the plane formed by the three needles. The grippers 3 are in their rear end position, ie in their direction of movement reversal point, in which they have the greatest distance to the needles. Shortly before reaching this position of each gripper 3 in each case a previously generated thread loop 37 of the upper thread, which was devoured with the associated lower thread 25, due to the movement away from the needles 2, jumped from the grippers 3. This process will be discussed in more detail below for the next following entanglements between the respective upper thread 5 and the associated respective lower thread 25. As shown here, at the time when the needles 2 are in their bottom dead center, and the thread feeder 1 1 is arranged in its bottom dead center. The Fadenanzugsfeder 10 has now moved with its bracket 15b from its left in the illustration stop 40 in the direction of its upper stop 41 in which it exerts the greatest spring tension on the respective upper thread. The passive Fadenanzugsfeder 10 has been transferred due to an increasing thread tension in the upper threads 5 by the latter in this position. In Fig. 6, all the needles have along their respective longitudinal axis a little further up in the direction of their top dead center or their upper position, which co-determined the Schiingenhub moved and have already begun to release a needle thread loop 37. The grippers 3 have moved here in a pivoting movement, in the illustration of Fig. 6 to the right, to the needles 2 and the latter approximated. Likewise, the thread take-up 11 is in an upward movement. The Fadenanzugsfeder 10 is due to a due to the upward movement of the needles 2, also in the field of Fadenanzugsfeder 10 decreasing tension in the upper threads, relieved. The spring force of. Fadenanzugsfeder 10 therefore causes a pivoting movement of the bracket 15b of Fadenanzugsfeder in the direction of its first stop 40, in which the Fadenanzugsfeder 10 has the least spring force.

On the way from their position in FIG. 6 to their position in FIG. 7, the grippers 3 have already passed the longitudinal axes of the needles 2. As is apparent from Fig. 7, the gripper 3 are already passed with their respective tip by their respective associated only one loop 37. Also, each of the hook tip exiting bobbin thread 25 is thereby performed with a section already by its respective associated loop 37. The thread take-up 11 executes a synchronous with respect to the needles 2 movement and is also in an upward movement. The Fadenanzugsfeder 10 is further relieved due to the decreasing Oberfadenspannungen and is still on their way to their first stop 40, in which the Fadenanzugsfeder 10 has the lowest spring force

In Fig. 8, the gripper 3 have moved on their predetermined curved path, in the embodiment here on a circular arc path, on the gripper tip side end position and are in the illustration of Fig. 8 in this motion reversal position. The grippers 3 have taken the loop 37 as far as possible on their upper legs 3b, the loops 37 are each tight, ie with the least possible lateral deflection executed. A portion of the upper leg 3b of the respective gripper is arranged with the gripper tips in this position below the Spreizerstifte 39. The grippers 3 have by their pivotal movement in each case their lower thread 25 on a particular side of the Spreizerstifte 39 arranged, namely the side in the direction of which the Spreizerstifte 39 are moving below. In the illustration of FIG. 8, the lower threads are thus guided in each case behind one of the spreader pins 39. The needles 2 are now in the position of their top dead center, in which their needle thread loop is the largest.

8 also includes the representation of the front view of the sewing machine of Fig. 1. As is apparent from Fig. 1, are at this time the thread take-11 as well as the needles 2 in their top dead centers. The needle and thread take-up movements and the Nähgutvorschubbewegung lead to an increase in the thread tension in the upper threads 5, which is why the Fadenanzugsfeder 10 is loaded with its bracket 15 b through the upper threads 5 maximum. The Fadenanzugsfeder 10 is therefore held with the spring force resulting from the tension of the upper threads 5 in its upper, second end position 41 and lies with its bracket 15b with this spring force on the upper threads. The Fadenanzugsfeder 10 thus ensures that the Oberfadenschiingen 37 are streamlined and have a small lateral deflection.

Fig. 9 shows a current position of Spreizerstifte 39, in which the Spreizerstifte 39 already started with their lateral deflection movement and their respective associated associated a bobbin thread. The carrier 38 of the spreader elements, together with the spreader pins 39 held and moved by the latter, has been moved backwards with respect to the illustration of FIG. 9 and its plane of drawing. The spreader pins have in this case the respectively immediately before each Spreizerstift 39 arranged lower thread 25 taken along with this movement and thereby deflected in the direction of movement of the corresponding Spreizerstifts 39. The needles 2 have already left their position in their top dead center and are again on their way towards their bottom dead center, but are still arranged above the upper leg 3b of the gripper 3. The needle 2 have just stabbed into the fabric. The grippers 3 now move in a direction opposite to the previously assumed direction of movement towards the second end position of the grippers facing away from the gripper tips. The needles 2 pass - due to the deflection of the lower threads 25 and - with respect to the illustration of Fig. 9, each associated with the needle and emerging from this gripper 3 Bobbin thread 25 in front of this lower thread 25. The needles 2 then begin to form the following upper thread loop 37a. The needle thread loop 37 formed just before is still gripped by the respective gripper 3, as shown in FIG. 9 and also in FIG.

In the illustration of FIG. 10, the needles 2 have moved further in the direction of their bottom dead center and have also passed the grippers 3. The upper threads 5 leading thread feeder 11 continues to move synchronously with the needles 2 and also in the direction of its bottom dead center. Furthermore, the grippers 3 have covered a further subsection in the direction of their second end position facing away from the gripper tips, which in the illustration of FIG. 10 is located on the left side. Each lower thread 25 is further deflected by a spreader pins 39. The lower threads 25 come hereby in each case against the associated one needle 2 in Appendix. In a subsequent upward movement of the needles 2, the lower threads 25 jump off from the needles 2 or are released from the needles and then there is an entanglement between each of a lower thread 25 and a loop 37 of one of the upper threads 5 instead.

With reference to the stitch pattern phases of FIGS. 9 and 10, in which the needles 2 are in their downward movement towards their common bottom dead center, the thread take-up spring 10 pivots from its previously assumed upper end position 41 in which it is loaded with its maximum spring force is, towards its left-side end position 40, in which it has the least spring force and thus can apply at least almost no tensile force on the upper threads 5. The still located on the respective gripper 3 and formed in the previous Stichbildevorgang Oberfadenschiingen 37 are each kept taut on their respective grippers 3. By relieving the Fadenanzugsfeder 10 train is applied to the otherwise comparatively low tensioned or even almost loose upper thread compared to other thread conditions.

In Fig. 12 is to illustrate a possible for the invention and advantageous principal course of the force exerted by the thread tightening means 10, in the case of the embodiment of a spring force. In other embodiments, the force provided for Fadenzugug force in other ways than by a spring to be provided. This force acting on the at least one, preferably on all upper threads at the same time, is variable during a stitch formation cycle, that is to say from a position of the needle tips in their top dead center until the subsequent top dead center is reached again. As can be seen from the diagram of FIG. 12, it is preferable in this case for the force exerted by the thread tightening means to occupy several times a maximum value, at least one local maximum value, during the aforementioned stitch formation cycle. Likewise, during a stitching cycle, the force of the thread tightening means may take on a minimum value, at least in each case a local minimum value, several times. It has proven to be advantageous in this case if at least local maximum force values acting on the upper threads are set in the upper and lower dead center of the needles. Minimum force values can be present in particular when the needles penetrate into the sewing material and / or when the needle tip leaves the sewing material in the upward movement. Like the path of the needles, the course of the force of the thread tightening means can also correspond to a cosine curve or a cosine function. As shown in FIG. 12, the respective minimum value may be a non-zero positive value of the force. It is also possible that at least one of the minimum values during a stitch formation phase has the value zero. Thus, as shown in the embodiment discussed herein, the invention, despite a very small needle spacing of adjacent needles 2, which are arranged according to the inline principle of a multi-needle chain stitch sewing machine, allows a secure seaming of seams running parallel to each other at a small distance become. It can be avoided in particular that adjacent, ie belonging to an adjacent seam stitching tools, detect an upper thread and thus prevent seaming. LIST OF REFERENCE NUMBERS

Multi-needle chain stitch machine 18 shaft

a top 19 eccentric

b lower part 22 rear end

Needle 23 hook tip

Gripper 24 recess

a lower leg 25 bobbin thread

b Upper leg 26 Lower thread stock

c connecting leg 27 recess

Thread guide Upper threads 28 Lower thread separation aid

Upper thread 35 Needle guard

Thread supply 36 strut

Thread brake 37 Upper thread loop

Guide eye 37a subsequent Oberfaden¬0 Fadenanzugsmittel loop

1 thread take-up 38 carrier

4 carrier 39 Spreizerstift

5 coil spring 40 left stop

5a front end 41 upper stop

5b strap

6 Gripper carrier E eccentricity

7 eccentric drive

Claims

claims

A multi-needle chain stitch sewing machine having a plurality of needles (2) for receiving one upper thread (5) each, said plurality of needles being spaced apart along a straight line and being movable synchronously with each other, and said line being at least substantially orthogonal to the intended feed direction a fabric transport is aligned,

with a yarn guide (4) for the plurality of upper yarns to guide each upper yarn (5) from its yarn supply (6) to its associated needle,

with several in each case for guiding a lower thread (25) leading

driven grippers (3), wherein the grippers (3) are arranged at a distance from each other and are movable synchronously with each other, by the movements of the gripper (3) and the needles (2) each an upper and a lower thread (5; 25) entwined with each other are to thereby simultaneously a plurality of mutually parallel seams in the fabric to produce with in the feed direction without offset to each other in the fabric arranged injection points of the needles, and a motor having at least one drive means with which in a predetermined manner and coordinated with each other, the movements of the needles and the Grippers can be generated,

characterized by a thread take-up means (10) arranged in the area of the thread guide and provided in addition to a thread feeder (11) for at least one of the upper threads (5), with the at least one of the upper threads in the area between the thread take-up means (10) and the at least one Upper thread (5) associated needle (2) with an additional thread tension is providable.

Multi-needle chain stitch sewing machine according to claim 1, characterized in that said at least one thread tightening means (10) moves with respect to a course of upper threads (5), between at least one thread brake (7) of these upper threads (5) and together with the needles (2) Thread feeder (1 1) is arranged.

3. Mehrnabekettenstichnähmaschine according to at least one of the preceding claims, characterized in that for several, preferably for all, upper threads (5) a common Fadenanzugsmittel (10) is provided with the same time on the plurality of upper threads (5) can be acted upon.

4. Mehrnabekettenstichnähmaschine according to at least one of the preceding claims, characterized in that the Fadenanzugsmittel (10) is a passively moved, acting on at least one of the upper threads, element.

5. Mehrnabekettenstichnähmaschine according to at least one of the preceding claims, characterized by a Fadenanzugsmittel (10) which is provided for resting on at least one, preferably on all, upper threads (5).

6. Mehrnabekettenstichnähmaschine according to at least one of the preceding claims, characterized in that the Fadenanzugsmittel (10) is designed as a mechanical spring element, or as a pneumatically acting element or as a cam-controlled element, the movable to a

Drive device of the sewing machine is coupled.

7. Mehrnabekettenstichnähmaschine according to at least one of the preceding claims, characterized in that during a Stichbildezyklus the Fadenanzugsmittel (10) exerts a variable magnitude force on at least one of the upper threads.

8. Mehrnabekettenstichnähmaschine according to at least one of the preceding claims, characterized in that the Fadenanzugsmittel (10) during a Stichbildezyklus in which move the needles from its top dead center to a bottom dead center and back to top dead center, at least two, preferably at least three , At least local maximum values of the thread tightening agent on the at least one upper thread (5) force exerted.

9. Mehrnabekettenstichnähmaschine according to at least one of the preceding claims, characterized in that the Fadenanzugsmittel (10) during a Stichbildezyklus in which move the needles from its top dead center to its bottom dead center and back to top dead center, at least two, at least local minimum values the force exerted by the thread tightening means (10) on the at least one upper thread, has.

10. Mehrnabekettenstichnähmaschine according to at least one of the preceding claims, characterized in that the Fadenanzugsmittel (10) each having an at least local maximum force on at least one of the upper threads (5) exerts when the needles (2) pass through their upper and lower dead center. ,

1 1. Mehrnabekettenstichnähmaschine according to at least one of the preceding claims, characterized in that the Fadenanzugsmittel (10) on the way of the needles (2) both between the upper and lower dead centers and on the way between the lower and upper dead centers each at least one have at least local minimum value.

12. Mehrnabekettenstichnähmaschine according to at least one of the preceding claims, characterized in that the needle spacing of adjacent needles (2) from a range of 4.4 mm to 2.6 mm,

is preferably selected from 4.2mm to 2.8mm and more preferably from a range of 3.8mm to 3.0mm.

13. Mehrnabekettenstichnähmaschine according to at least one of the preceding claims, characterized in that a Spreizerausweichbewegung is selected from a range of 4.5 mm to 4.7 mm.

14. Mehrnabekettenstichnähmaschine according to at least one of the preceding claims, characterized in that an eccentricity of a roller or cam drive of at least one, preferably of all grippers, from a range of 4.8 mm to 4.0 mm, preferably with a value of 4 , 4 mm is selected.

15. Mehrnabekettenstichnähmaschine according to at least one of the preceding claims, characterized by a needle spacing of longitudinal axes of adjacent needles, from a range of 3.8 mm to 3.0 mm, preferably from 3.6 mm to 3.1 mm, and particularly preferably with a Value of 3.2 mm.

16. A method for the simultaneous generation of juxtaposed

Chain stitching by means of a Mehrnadelkettenstichnähmaschine with several for receiving one of an upper thread (5) leading provided needles (2), wherein the plurality of needles along a straight line each spaced from each other and moved synchronously with each other, and the line at least substantially orthogonal is aligned to the intended feed direction of a fabric transport, wherein the plurality of upper threads are guided in the Mehrnadelkettenstichnähmaschine means of a thread guide (4) to guide each upper thread (5) from its thread supply (6) to its associated needle, and

a plurality of lower threads (25) are provided, each guided by means of one of a plurality of driven grippers (3), wherein the grippers (3) are spaced apart and moved synchronously with each other, and by the movements of the grippers (3) and the needles (2) in each case an upper thread and a lower thread (5; 25) are entangled with each other, thereby simultaneously several parallel to each other extending seams with in

Feed direction without offset each other arranged in the fabric

To create injection points of the needles, wherein

by means of at least one motor of a drive device in a predetermined manner coordinated movements of the needles and the gripper are generated, characterized by

a arranged in the region of the thread guide and in addition to a

Thread catcher (11) provided Fadenanzugsmittel (10) for at least one of the upper threads (5), wherein with the Fadenanzugsmittel (10) at least one of the upper threads in the area between the Fadenanzugsmittel (10) and the at least one upper thread (5) associated needle (2 ) is provided with an additional thread tension.