JPH05237275A - Device for forming multi-thread chain stitch and feed and throat plate for the device - Google Patents

Abstract

PURPOSE: To provide a device for forming multi-thread chain stitches and a feed and a throat plate for the device. CONSTITUTION: In order to prevent the loosening of a stitch at the time of multi-thread chain stitch (cover stitch seam) formation performed by using two or more needle threads and at least one looper thread but without using an attaching thread depending on the case, other than cloth pressers 3 and 3' for holding the just formed stitch, holding devices 10, 12, 16 and 17 for holding the chain stitch for performing the action of reducing tension acting on the just formed stitch every time are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for forming a double chain stitch according to the preamble of claim 1 and a device for forming the double chain stitch according to claim 5. And a needle plate for the device according to claim 8.

[0002]

2. Description of the Prior Art Devices of the type described at the outset are already commercially available in various configurations. Double chain stitch seams (cover stitch seams (Ueberdecknaht)) formed by these devices are described, for example, in US Industrial Standard 402,4.
03,405-407 and 601-604. Usually the fabrics are sewn one after the other, so that there is no problem with the seam for the sewing operation to proceed uninterrupted. However, at times it may be desirable to keep loop stitches knitted from the suture thread used after sewing the fabric, so-called thread loops, as a seam with a stable connection. This stable seam retention is achieved by using cover threads on the front side of the fabric in addition to the upper thread and the lower looper thread, and by using the warp thread on the front side of the fabric. By forming a seam (seam), it can be reached that way rather intentionally.

In such a method, the thread usage is increased, the seams are tight (which is sometimes undesirable), and in some cases the top seams can impair the desired appearance. On the other hand, American Industrial Standard 402
Alternatively, when the seam is formed without using the counter thread as indicated by 406, the desired stable thread is obtained from the three suture threads used (of course, a large number of suture threads may be used). The loop (Fadenkette) has never been achieved.

[0004]

The problem underlying the invention is, in any case, the American Industrial Standard 40.
A device of the type described at the beginning and an improved feed and throat plate for this device, so that a stable thread loop is obtained even when sewn without using warp threads according to 2 and 406 , To provide.

[0005]

According to the present invention, it is possible to obtain a thread loop which is stable even in the case where the fabric is lacking. In order to be achieved, the problem is solved by the provision of a retaining device for retaining the newly formed seam during the formation of the next seam.

With the above-described structure according to the present invention, by recognizing the special circumstances in the sewing process, that is, the stitches or stitches are continuously formed, the disadvantageous tension by the needle acts on the stitches just finished to be sewn. It is based on recognition. While the fabric to be sewn was present, we did not pay attention to this condition because the seams were always in a stable condition. The basis for this stabilizing effect is that it is conditioned by the friction of the threads in the fabric, which prevents the unraveling of the seam, whereas on the other hand, when the fabric is not present, the tension of the threads is blocked. Such an action does not occur.

By virtue of this arrangement according to the invention, the retention of the thread during seam formation allows the tension counteracting effect seen in the presence of the fabric to be obtained even in the absence of the fabric. Be done.

The holding device can be constructed in different ways, but a structurally simple construction is achieved by the features of claim 2 of the claims. This is because by providing another tooth row surface in parallel with the first tooth row surface, the seam formed on the lower side is first fed back and forth without tension acting on this seam. is there.

According to claim 3 of the claims,
The webs formed one behind the other cooperate with a fabric retainer to hold the loop just finished to be sewn, by configuring this seam to hold it in the unstable area without tension. The above effect can be achieved more reliably.

From the understanding underlying the present invention, it becomes immediately clear that the behavior of the tension can be changed not only by the stitch length, but also by the sewing speed and the feed speed. Therefore, the configuration according to claim 4 is particularly advantageous. This is because this construction further reduces the tension acting on the individual seams formed.

The features of the feeding according to the present invention are as follows.
According to claim 5 the feed comprises another similarly projecting ridge with feed teeth spaced forward from it in the feed direction of said projecting ridge. It is that you are.

[0012] In this case, it is not impossible to provide the tooth surfaces which are in succession with each other-according to the movement given to the feed-on different surfaces, but according to the configuration of claim 6 of the claims. It is advantageous to provide the feed teeth rows which are arranged one behind the other in the same plane.

Forming the two ridges which are likewise one behind the other-depending on the construction of the feed plate and the movement given to the feed-inclining towards one another, for example so that the installation positions converge. It is also possible, but if the feed is constructed according to the features of claim 7, i.e., the projecting longitudinal axes of the ridges are arranged at least approximately parallel to one another. It is advantageous for the feeding movement course.

From the above, a needle plate having the features of claim 8 is particularly advantageous for solving the problem underlying the present invention. Hereinafter, the present invention will be described in detail with reference to the embodiments illustrated in the accompanying drawings.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the double chain stitch shown in FIGS. 1 and 2, two upper threads A and A'run in parallel, and these threads have two threads (in other embodiments, It is also possible to use multiple needles to form a double chain stitch) needles not shown here are used to pierce the fabric to be sewn in the usual way. At least one looper known per se, which is not shown on the lower side (in this case the expression lower side does not necessarily indicate the position of the needle as the looper can also be in a horizontal position) Threads A and A'are joined together by looper threads B to form a seam. If there is no fabric in the meantime, there is generally the risk that the formed seam will be unraveled if no additional warp threads are provided on the upper side. That is, the lack of stability of the thread loop thus formed poses the risk that the seam will naturally unwind again when tension is applied.

The embodiment according to the invention consists essentially of four parts, as shown in FIG. The needle plate 1 is provided between the feed 2 and the cloth retainers 3 and 3'consisting of two parts. The needle plate 1 comprises a slit 4 for passing the upper thread and the looper thread-comprising two extensions 5 and a threading slit 6 forming a U-shaped stirrup. In both regions of the end of the closed U-shaped extension or, if appropriate, in any other position of the extension, needle passage holes 7 for at least two needles for guiding the upper thread are provided. ing. The two extensions 5 and the threading slit 6 of the U-shaped slit 4 are oriented in the feed direction and form the three sides of the needle plate tongue 8 which separates the fabric and the looper thread. As the fabric to be sewn is fed from the needle hole 7 along the extension 5 towards the stirrup 6, the looper thread is tied directly to the fabric in the region of the stirrup.

Following the threading slit 6 in the feed direction, a region of the needle plate 1 which is formed as a lateral web 10 follows because a through hole 9 is continuous in the feed direction. At least one other through hole 11 and the other web 12 are provided so as to be continuous with the through hole 9 in the throwing direction. Web 1
0, 12 and 8 act as stiff underlays against which the fabric is pressed by the fabric retainers 3, 3 ', so that the fabric is retained as the needle pierces the fabric.

According to a particular embodiment, at least one,
Two through-holes 13 are preferably provided on the side of the U-shaped slit 4 in the feed direction--in particular in the case of two through-holes--on both sides. Depending on the case, it is possible to provide another through hole 14 in a direction opposite to the feeding direction of the U-shaped slit 4. The needle plate 1 has a hole 15 for fixing the needle plate 1 to the sewing machine.

The feed 2 has one tooth row 16, 17 respectively.
And at least two advancing faces which are one behind the other in the feed direction, in the manner of teeth arranged in rows, which are generally formed by feed teeth which are oriented in the feed direction. These feed surfaces must exert a stiction force large enough to feed the fabric on the fabric pressed against them, and for this purpose a flat or surface structure with ribs, grooves or cams is applied. Have Optionally at least one, preferably two, teeth 18 are lateral to the rupture 16 with respect to the feed direction-in particular in the case of two sides-on both sides-
It is provided. The tooth rows 16, 17 and 18 are the end surfaces of the ridges 16a, 17a of the feed 2, the longitudinal axes of which are oriented in particular parallel to one another, and the through holes 9, 11, 1 of the needle plate 1 are provided.
3. Fit in 3 so that the required feeding movements can be made. When feeding the fabric, the tooth rows 16, 17, 18 penetrate through the through-holes and press the fabric against the fabric retainers 3, 3 ', so that the fabric is sufficient to follow the movement of the feed 2 in the feed direction. Tightened to be. The provision of the feed surface according to the invention enables tension-free feed of the flatly formed chain stitch. Since it is possible to further provide a through hole 14 in the needle plate 1, it is possible to provide the feed 2 with another sliding surface which fits in this through hole 14.

The part 3 of the fabric retainer is generally in front of the part 3'in the feed direction and is provided with a fixing and guiding part 19. A holding hole 20 for a fixing rod for fixing the cloth presser to the sewing machine passes through this portion 19. The other hole 21 in the part 19 leads to the hole 20 and the part 19
The screws for tightening and fixing the to the process rod are housed.

On the surface 21 of the part 19 which is formed perpendicularly to the needle plate 1 in the assembled state on the fixed rod-particularly in the end face of the part 19 when viewed in the feed direction-the leg of the fabric retainer is formed. A guide device 22 is provided which allows a vertical movement of 23 needle plates 1. In the embodiment according to the invention, between the face 21 of the part 19 and the guide plate 22 fixed to this part 19 there is a long leg of the L-shaped profile piece of the foot 23 of the fabric retainer. ing. In particular, at least two screws are used to fix the guide needle plate 22 described above,
These screws are provided vertically above and below the needle plate 1. For this fixing, a guide slit is provided as a through hole in the long leg portion of the L-shaped profile member of the leg portion 23 of the cloth retainer. There is.

A pushing device, in particular a spring 24, projects from a plane of the part 19 which is oriented in the direction of the needle plate 1 and parallel to this needle plate, which spring of the L-shaped profile of the leg 23. The short leg, and thus the entire leg 23, is pressed against the needle plate 1. The pre-tension of the spring 24 is adjusted by the screw present in the bore 25 of the part 19. Foot 23 of cloth holder
The holding bottom 26 of FIG. 1 exerts a pressing force in the areas of the webs 10 and 12, the through holes 9 and 11, and the feeding surfaces 16 and 17. The foot 23 of the fabric retainer cooperates with a corresponding feeding surface for feeding the finished seam without distortion. When the thickness of the fabric changes, the elastically guided legs 23 of the fabric retainer can be adapted to the respective fabric thickness. Thus, the present invention ensures that the seam remains tensionless during its formation and that the resulting thread loops are stable in the absence of fabric.

The foot 23 of the fabric retainer has a connecting portion 27 with a somewhat narrower thin cross section in the end region opposite the feed direction. This connecting portion is inserted into the cutout portion in the presser foot bottom portion 28 of the cloth pressing portion 3 '. Two through holes 29 for needles for guiding the upper thread are provided in the central region of the presser foot bottom portion 28. Presser foot bottom 28
Is an extension of a presser foot bottom portion 26 that is rotatable about an axis 30 that stands parallel to the needle plate 1 of the cloth pressing portion 3 and perpendicular to the feed direction. This pivotability of the extension is advantageous when the thickness of the fabric changes. The presser foot bottom portion 28 is formed so as to be angularly spaced from the needle plate 1 in the starting end region with respect to the feed direction thereof, and therefore the fabric to be supplied is not caught on the end face of the presser foot bottom portion and is always held by this presser foot. You will be guided under the gold bottom. If a fabric consisting of multiple layers has to be sewn, the part which lies in the region of the needle of the fabric retainer, namely the presser foot bottom 28, is such that the fabric layer is correctly guided under the through hole 29 and It is turned so as to be pressed by. The presser foot bottom portion 26 remains parallel to the needle plate 1 and ensures a pressing force and a feed that are not affected by an increase in the thickness of the fabric.

The presser foot bottom portion 28 is provided with two side plates 31 formed in the end region in the feed direction so as to be separated from the needle plate 1, and the shaft 30 is held in the side plates. Between these side plates 31, there are legs 33 of the fixing device 32. The presser foot bottom portion 28 has the fixing device 3 only via the shaft 30 supported in the starting end region of the leg portion 33.
Combined with 2. The fixing device comprises a fixing flange which is screwed onto the lower end of the fixing rod which is guided through the hole 20 in the fixing part 19.

A presser foot bottom portion 34 is fixed to at least one side surface of the presser foot bottom portion 28 so as to be vertically slidable with respect to the contact surface. In order to allow a sliding movement, a guide device is provided, which in particular consists of a guide pin 35 which is provided vertically on the presser foot bottom part 34 and a guide jacket which integrally surrounds the guide pin. There is.
This guide jacket is fixed to one of the side plates 31 from the outside. In the spring 36, the presser foot bottom portion 34 has a presser foot bottom portion 2
The guide pin 35 and the side plate 31 are fixed so as to be pressed against the needle plate 1 while being separated from the end portion of No. 8.
By pressing the presser foot bottom part 34 on the one hand through the through hole 13 or on the feed surface 18 on the other hand the part of the needle plate 1 which is continuous with this through hole or on the fabric which is present over this entire area. , The fabric is properly retained within the area of the needle, both when the needle is pierced and during feeding.

In order to further reduce the thread tension which acts to pull up the seam in the absence of fabric, the preferred embodiment of the present invention provides a fabric edge sensitive sensor, such as a mechanical sensing device, a capacitive sensor. The sensing device or the like is provided with an opto-electric sensor, which in this embodiment comprises a power supply 37 for electromagnetic waves (visible or invisible) and an opto-electrical converter 38. Such a cloth edge detecting sensor is provided at an arbitrary position itself, but in the vicinity of the needle plate 1, so that the edge of the cloth is detected at an appropriate time and the cloth edge signal is given.

The fabric edge signal is applied via a conductor 39 to a drive mechanism d, known per se and therefore not shown here in detail, for driving the feeder 2.
Is controlled to reduce speed and / or increase stitch length. That is, it was found that as the stitch length increased, a stable thread loop was obtained even when the fabric was not present. It is therefore clear that such a control is suitable for solving the problem even without the fixing device according to the invention being provided.

As is clear from FIG. 4, the needle plate 1 is also subjected to braking and unfavorable thread tension braking on the surface opposite to the cloth presser 3 or on the surface facing the feeding device 2. Advantageously, it is provided with a recess 40 and a projection 41 for capturing.

[0029]

With the configuration according to the present invention as described above,
When forming a double chain stitch as a cover stitch seam, it is possible to retain the thread loops as they are formed, even in the absence of fabric, thus avoiding the unwinding of this stitch. It

[Brief description of drawings]

FIG. 1 is a schematic view of a double chain stitch stitch as displayed in American Industrial Standards 402 and 406.

FIG. 2 is a schematic view of a double chain stitch stitch as displayed in American Industrial Standards 402 and 406.

FIG. 3 is a view of the device according to the invention with the delivery device according to the invention and the needle plate according to the invention disassembled so that the upper side is visible.

4 is a vertical cross-sectional view taken along the section line IV-IV in FIG.

[Explanation of symbols]

 1 Needle plate 2 Feeding device 3 Cloth retainer 3'Cloth retainer part 4 Slit 5 Extension part 6 Stirrup part slit 7 Needle through hole 8,10,12 Weave 9, 11, 14, 14, 29 Through hole 13 15 Hole 16,17 , 18 tooth row 16a, 17a raised part 19 fixed and guiding part 20, 25 hole 21 face 22 guide plate 23 cloth presser leg 24, 26 spring 26, 28 presser foot bottom 27 connection part 30 shaft 31 side plate 32 fixing device 33 Leg part 34 Presser foot bottom part 35 Guide pin 37 Power source 38 Converter 39 Conductor wire 40 Recessed part 41 Convex part A, A'Upper thread B, B'looper thread

Claims (9)

[Claims] 1. A ridge (1) which acts through at least one through hole (9, 11, 13, 14) of the needle plate (1).
6a) has at least one feed tooth row (16, 17, 1)
8) with a feed (2), on the other side of which a fabric retainer (3, 3 ') is provided facing this feed, which fabric retainer in the direction of the needle plate (1). It comprises at least two parts (3, 3 ') which are movable relative to one another, at least one of these parts being actuated by a load device in the direction of the needle plate (1), at least one of which is the cloth. Presser bottom (28) with connecting device (20, 32) for attaching the presser to the sewing machine and at least two needle through holes (29) for needles through which the upper thread is passed.
Two parallel running upper threads (A,
A device for forming a double chain stitch from A ') and at least one looper thread (B) connecting these upper threads (A, A') to each other below the seam in the material to be sewn. In order to ensure a stable thread loop even in the absence of a double thread, a double holding device is provided which holds the newly formed seam during the formation of the next seam. A device for forming chain stitches. 2. A holding device for the feed (2) comprises a needle plate (1) in front of the first feed tooth row (16) when viewed in the feed direction.
2. Device according to claim 1, characterized in that it is provided with feed teeth (17) on a separately provided ridge (17a) projecting from it. 3. A holding device for the needle plate (1) comprises, in addition to the first web (10), at least one web (12) formed between successive feed tooth rows (16, 17). ), And the web (10) has the upper thread (A, A ′) in front of the first feed tooth row (16).
And a looper thread (B) for passing through the U-shaped slit (4).
Device according to claim 1 or 2, characterized in that it comprises a U-shaped extension (5) pointing in the opposite direction to the feed direction. 4. A sensor device for providing a fabric end signal is provided, and the feeder drive mechanism lengthens the stitch length when the fabric end signal is applied and / or
Alternatively, the device according to any one of claims 1 to 3, characterized in that it is configured to be controllable to reduce the feed rate. 5. A tooth row surface (16) provided with a raised portion (16a) projecting so as to project the needle plate (1), and having a feed dog directed to the feed direction on the upper side of this pedestal. ) Is provided, this feed (2) likewise has a feed tooth row (17) spaced forward from it in the feed direction of said protruding ridge (16a). A feed characterized in that it is provided with another ridge (17a). 6. Feed tooth rows (16, 17) which are arranged one behind the other.
6. The feeding device according to claim 5, wherein are present in the same plane. 7. Protrusions (16a, 17) that are in series with each other.
7. Feeding device according to claim 5, characterized in that the feed teeth (16, 17) according to a) are oriented at least approximately parallel to one another. 8. A needle plate (1) having at least one through hole (9) through which a ridge having a tooth surface (16) for feeding the cloth of the feeding device (2) passes. Has at least one through hole (11) in front of this through hole (9) when viewed in the feed direction, in which case these through holes (9, 1)
A web (12) for dividing them between 1) is provided in addition to the first web (10) existing in front of the web (12) in the feed direction, and the web (12) is provided. A needle plate characterized in that it is delimited by a through hole (9) on the one hand and a U-shaped slit (4) edging the tongue of the needle plate on the other hand, which points in the feed direction. 9. The throat plate (1) has a surface, which is provided with at least one recess (40) and a projection (41) on the side opposite to the fabric retainer (3), in particular a corrugated surface. The needle plate according to claim 8, wherein