EP0541923B1 - Thread cutting and clamping device for the back thread or lower thread of an embroidering machine - Google Patents

Abstract

In an embroidering machine, there is a thread clamping and cutting device for the back thread or lower thread (10), a shuttle (3) being mounted displaceably in a shuttle guide (6), both a displaceable thread clamping device (16) and a cutting device (25) being provided. The cutting device (25) is constructed in the form of a cutting blade, the cutting edges being designed independently of the thread clamping device of the back thread or lower thread, and the thread clamping and cutting device being arranged in the region of the needle hole (15). Arranged in continuation of the cutting device is a clamping gap (17) of the thread clamping device (16), the thread which is previously clamped by the cutting device and subsequently cut off being gripped and fixed in the clamping gap (17) located behind it in the cutting direction. <IMAGE>

Description

The present invention relates to a thread clamping and cutting device according to the preamble of claim 1. Such a device has become known, for example, with the subject of DE 20 65 264.

Here, in a manner known per se, a shuttle is slidably mounted in a shuttle guide and the thread clamping and cutting device is driven displaceably via a rotary mechanism, the displacement direction of the clamping and cutting device extending perpendicular to the direction of transport of the shuttle.

The disadvantage of the known arrangement is that each thread clamping and cutting device must be assigned its own movement drive in order to ensure a separate control at all. However, this has the disadvantage that a relatively large space requirement for the separate drive is required per clamping and cutting device. Such an arrangement cannot be used in the conventional shuttle embroidery machine with 4/4 repeat due to the limited space requirement.

Another disadvantage of the known cutting and clamping device is that the length of the cut thread is relatively large. This will affect the embroidery on the back of the fabric and will result in high thread consumption.

Another disadvantage of the known arrangement is that the known clamping and Cutting device is arranged in the area of the shuttle guide, and therefore there is a risk that the thread path of the rear or lower thread is impaired, especially since the known clamping and cutting device penetrates the shuttle carrier.

Characteristic of this known embodiment is, moreover, that the cutting knife itself initiates the clamping process and that the clamping of the rear or lower thread depends directly on the cutting process itself. This means that after the rear or lower thread has been cut off, it is clamped between a clamping surface of a leaf spring and the cutting knife itself. However, this has the disadvantage that - if a new cutting process is required - the clamping is then released and the cut back or bobbin thread is released. In the case of embroidery sites that are currently out of operation on the needle side, the cut-back and free-hanging rear or bobbin thread runs up and down with the shuttle and is crushed, which can lead to a thread break when the embroidery site is sewn on again, or fallen stitches occur.

The present invention is therefore based on the object of developing an embroidery machine with thread clamping and cutting device of the type mentioned in such a way that, in the case of an embroidery point circuit initiated manually or mechanically on the needle side, the rubbing of the idling rear or under thread on the shuttle side is avoided with certainty.

The technical teaching of claim 1 serves to solve the problem.

An essential feature of the present invention is that it is clamped independently of a cutting process of the rear or lower thread.

I.e. the clamping is independent of the movement of the cutting knife of the cutting device. In the prior art, as described above, the cutting knife was at the same time a clamping element, as a result of which the above-described disadvantage of the freely coming back or under thread was created.

Since it is provided in the present invention that the clamping takes place independently of the cutting process, there is the advantage that all the shuttle threads are first cut off and then transported to a clamping device which works independently of the cutting process, where they are held, when the cutting knife goes back and cuts again.

This has the advantage that the cut back or bobbin thread is fixed in any case in the clamping device and can no longer be released by a newly moved cutting knife.

The rear or lower thread is then released from this clamping by a corresponding pull on the rear or lower thread, when the back or lower thread is tied into the front thread when the corresponding embroidery site is sewn on and the pull on the rear or lower thread is so strong is that it is pulled out of the nip according to the invention.

This ensures that, in the case of an empty embroidery site which is switched off on the needle side, the shuttle going back and forth cannot damage and rub through the clamped back or bobbin thread.

For the rest, it was previously known to eliminate this disadvantage, to stop the boat itself in order to rub the rear or To avoid bobbin thread. However, the shutdown of the shuttle drive involves considerable mechanical effort, which is avoided according to the present invention.

Another important advantage of the present invention is that there is only a very small space requirement for the cutting and clamping device on the shuttle side, because there is no longer a separate movement drive for each cutting and clamping device, as in DE 20 65 264, but according to the present innovation, all cutting and clamping devices are operated simultaneously and simultaneously via a common actuating rail.

The present invention comprises two different embodiments, both of which are intended to be encompassed by the present inventive concept.

In a first preferred embodiment of the present invention it is provided that the cutting knife itself is provided as an actuating element for initiating the clamping. I.e. the cutting knife brings the cut back or bobbin thread into the clamping device according to the invention and leaves it there. This means that when the cutting knife is pulled back again, the rear or lower thread remains in the clamping device without being able to be released from this clamping device by a retracting movement of the cutting knife, as is disadvantageously the case in DE 20 65 264.

In a second embodiment it is provided that the clamping process to be initiated independently of the cutting process is initiated by a separate actuating element, this actuating element being able to be moved independently of the cutting knife. This actuating element thus grips the cut back or bobbin thread and brings it into a corresponding clamping device, where it is held.

Another important advantage of the invention is that the cutting movement takes place parallel to the shuttle movement, which results in a small space requirement. Due to the fact that in DE-PS 20 65 264 arranged perpendicular to the shuttle carrier motion drives for the cutting and clamping mechanism takes up a large amount of space, which is not necessary in the present innovation, because with the present innovation the cutting and clamping mechanism is integrated in the tap hole plate , which is connected to the shuttle.

In a preferred embodiment of the present invention it is provided that the clamping device is arranged in the immediate vicinity of the cutting device and that the cutting edge of the cutting device is approximately aligned with a part of the clamping device. This ensures that thread clamping and cutting takes place at the shortest possible distance.

It is also essential that the thread cutting and clamping device according to the invention is approximately flush with the stitch hole in the throat plate, which also ensures that the cut back or bobbin thread is only a short length. This ensures that the remainder of the rear or lower thread remaining on the fabric is very short.

The fact that the cutting element is arranged in approximately flush juxtaposition with the thread clamping element has the further advantage that the cutting element only has to carry out a very short cutting stroke in order to cut off the rear or bobbin thread as intended.

Due to the fact that the entire thread clamping and cutting device is arranged in the throat plate, the result is Significant advantage that a drive part on the throat plate, which drive part takes over the movement drive for the thread clamping and cutting device, can be accessed with an external drive while taking up a small amount of space.

In a preferred embodiment of the present invention it is provided that the thread clamping device is designed to be stationary and the cutting knife is movably guided in the throat plate. Both parts are mounted in a corresponding sliding guide of the throat plate and can be pulled out as a whole part from this throat plate guide and replaced.

The subject matter of the present invention results not only from the subject matter of the individual patent claims, but also from the combination of the individual patent claims with one another.

All of the information and features disclosed in the documents - including the summary -, in particular the spatial design shown in the drawings, are claimed to be essential to the invention, insofar as they are new to the prior art, individually or in combination.

The invention is explained in more detail below with the aid of drawings which illustrate only one embodiment. Further essential features and advantages of the invention emerge from the drawings and their description.

Figur 1:

Schnitt gemäß der Linie I-I in Figur 2 durch eine Stichplatte einer Stickstation,

Figur 1a:

ein vergrößerter Schnitt durch die Stichplatte im Bereich des Stichloches,

Figur 2:

Seitenansicht der Anordnung nach Figur 1 in Richtung des Pfeiles II in Figur 1 mit Darstellung von drei verschiedenen Schiffchenführungen in drei verschiedenen Zeichnungsebenen der Figur 1,

Figur 3:

Schnitt gemäß der Linie III-III durch eine Fadenklemm- und Schneideinrichtung in Figur 2,

Figur 4:

Draufsicht auf eine Zwischenplatte,

Figur 5:

Draufsicht auf die Vorderplatte des Betätigungsschiebers,

Figur 6:

Schnitt durch die Vorderplatte nach Figur 5,

Figur 7:

Draufsicht auf die Rückplatte des Betätigungsschiebers,

Figur 8:

Schnitt durch Figur 7.

Show it:

Figure 1:

Section along the line II in Figure 2 through a stitch plate of an embroidery station,

Figure 1a:

an enlarged section through the needle plate in the area of the needle hole,

Figure 2:

Side view of the arrangement of Figure 1 in the direction of arrow II in Figure 1 showing three different shuttle guides in three different drawing levels of Figure 1,

Figure 3:

Section along the line III-III through a thread clamping and cutting device in Figure 2,

Figure 4:

Top view of an intermediate plate,

Figure 5:

Top view of the front plate of the actuating slide,

Figure 6:

Section through the front plate according to Figure 5,

Figure 7:

Top view of the back plate of the actuating slide,

Figure 8:

Section through Figure 7.

1 shows a needle plate 2, on one surface of which the fabric web 1 is guided in parallel. The throat plate is a plate-shaped part. Each stitch plate extends over several embroidery sites, e.g. over four embroidery points, and forms the shuttle guides 6, 6a, 6b for one shuttle 3 each.

The shuttle guides 6, 6a, 6b are thus formed on the throat plate 2 in the form of semi-open channels, in the area of which the respective shuttle 3 is moved by means of a displacement drive, not shown. In this case, the shuttle guides 6, 6a, 6b are in arranged obliquely on the throat plate 2 and the respective shuttle 3 is displaceably driven in the direction of arrow 4 in the shuttle guides 6,6a, 6b.

An intermediate plate 37 according to FIG. 4 is fastened on the throat plate 2, in which recesses 13 are provided for a plurality of guide parts 11. The guide parts 11 are preferably designed as plastic parts and are detachably and removably held in these recesses 13. According to FIG. 4, the recesses 13 are designed as slot-shaped recesses that are open on one side and into the one-sided opening of which the plastic guide part 11 can be inserted.

In Figure 1 it is shown that the plastic part 11 is held with a latching bracket 14 in the intermediate plate 37 and in the needle plate 2. The entire guide part 11, which is preferably made of plastic, can thus be pulled out of the intermediate plate in a particularly simple manner.

The guide part 11 has an inner recess 21 in which an actuating slide 18 is slidably guided. The type of actuating slide is shown in more detail in Figure 1 and in Figure 2 on the right side. The actuating slide 18 consists essentially of an actuating rod 26, which has an extension 8 at its lower end, opposite to which an extension 7 arranged on the guide part 11 is opposite. A spring 9 is provided between the two approaches. The force of the spring 9 thus holds the actuating slide 18 in a lower, lowered position, which is shown in FIG. 1.

The displacement drive for the actuating rod 26 and thus for the entire actuating slide 18 is effected by a cylinder 34, which acts via a piston rod 33 on a pivot point 32 which is arranged in the region of a pivoted lever 31.

The lever 31 is rotatably connected to a shaft 30, the length of the shaft extending over a certain number of embroidery points.

As soon as the piston rod 33 of the cylinder e.g. is suddenly driven in the direction of arrow 41, the lever 31 pivots clockwise into its position 31 'and thus lifts the extension 8 against the force of the spring 9 upwards, whereby the entire actuating rod 26 is moved upward in the direction of arrow 4.

The actuating slide 18 is connected to the actuating rod 26 by screws 27. The actuating slide 18 consists essentially of a U-shaped part which, according to FIGS. 5 to 8, essentially consists of a front plate 19 and a rear plate 20. Both plates 19, 20 form a mutual distance and thus a recess 21, in which the guide part 11 engages with a corresponding extension 12. This ensures that the actuating slide 18 is guided in a straight line in the region of the guide part 11.

In the front plate 19, a keyhole-shaped recess 22 is machined, which essentially consists of a bore 23 which merges into an elongated hole 24 in its upper part. According to FIG. 5, it is important that the lower edge of the bore 23 is designed as a cutting edge 25, it being sufficient that only the left area according to FIG. 6 has a cutting action, while the remaining, rounded area of the cutting edge 25 does not have a cutting action and is gentle on the thread .

In alignment with the keyhole-shaped recess 22 in the front plate 19, an identical keyhole-shaped recess 22 is machined in the rear plate 22 according to FIGS. 7 and 8. The lower limit of the bore 23 is not cutting and thread-trained, which also applies to all other boundary edges.

It is important that the counter knife 39 is locked in place and immovable in the guide part 11 and is therefore easy to replace.

In the non-cutting position, the bore 23 of the actuating slide 18 lies exactly flush with the stitch hole 15 machined in the throat plate.

A thread clamping device 16 is formed here, which essentially consists of a clamping gap 17.

This clamping gap is formed by a clamping finger 38, which is resiliently mounted on one side in the guide part 11 and is preferably formed in one piece from the plastic with the guide part 11 and, on the other hand, the clamping gap 17 is formed by a counter-clamping piece 40 which is inserted into the guide part 11. This inserted part (counter clamping piece 40) can be seen in FIG. 1.

It is now important that the clamping gap 17 lies in the direction of movement of the actuating slide (i.e. in the longitudinal direction of the shuttle guide - arrow direction 4) and that the clamping gap 17 forms an extension upward from the tap hole 15.

From the figures 2 (right-hand illustration) and FIG. 1, moreover, it follows that the V-shaped cutting edge 42 of the counter knife 39 with its V tip lies exactly in the central region of the clamping gap 17.

It is important, moreover, that the counter knife 39 according to FIG. 3 is designed as an approximately C-shaped metal part, the two of which lateral legs 43 are clipped onto the lateral surfaces of the guide part 11.

This special C-shaped design and the clipping of obliquely inwardly directed legs 43 has the advantage that the front surface 44 of the knife bulges inwards and thus adapt to the limits of the holes for the tap hole 15 and fit snugly. This ensures that the cutting front surface 44 of the counter knife 39 fits snugly and positively against the hole 23 of the front plate 19.

From Figure 3 it can also be seen that in the region of the guide piece 11, namely within the recess 21, the two interconnected plates 19, 20 of the actuating slide 18 are guided, the counter-clamping piece 40 being arranged between these plates. The clamping finger 38 is then arranged on the opposite side of the thread hole 15.

A clamping and cutting process according to the present innovation is described in more detail below.

According to FIG. 1, the rear or lower thread 10 is pulled out of the thread hole 5 of the boat 3 and runs through the stitch hole 15 in the position shown.

To clamp and cut off this thread 10, the cylinder 34 is actuated, so that the piston rod is pivoted suddenly into its position 31 'by the lever 31.
As a result, the actuating rod 26 is lifted upward and the actuating slide 18 with its two plates 19, 20 is displaced upward, the shoulder 12 immersing more strongly in the recess 21 in the guide part 11.

As a result, the thread 10 to be cut comes to rest on the movable cutting edge 25 in the region of the lower edge of the bore 23 and is then cut off as soon as the thread is in juxtaposition with the upper cutting edge 42 of the fixed counter knife 39. It is important here that with this feed movement of the actuating slide 18 in the arrow direction 4 upwards the thread is already in the area of the clamping gap 17 and is already cut there during the clamping.

This ensures that the thread is cut and held during cutting.

After the thread has been cut off, however, the actuating slide 18 continues to move upward in the direction of arrow 4, as a result of which the cut thread end reaches the upper region of the elongated hole 24 in the region of the keyhole-shaped recess 22 and remains in the clamping gap 17.

The thread is thus reliably clamped and can no longer be released from this clamping gap 17 even when the actuating slide 18 moves backwards in the direction of arrow 4. This is a significant advantage over the prior art, because in the prior art the movable cutting knife (which is given by the front plate 19 in the present innovation) simultaneously formed a clamping surface for the cut thread, which was associated with the disadvantage that when retracting this cutting knife this clamping surface was abandoned and the thread came free.

This is avoided in any case according to the present invention, because even when the front plate 19 is retracted, the thread remains in the region of the clamping gap 17 and is retained.

It is only possible to pull out this thread if, when this embroidery site is put into operation again, this cut thread is integrated with the front thread in such a way that there is sufficient tension on this cut back or under thread that is then sufficient to pull this cut thread out of the clamping gap 17 .

In addition, it is also noted that the rail 35, which has crankings previously referred to as lever 31, and that these crankings serve to actuate the respective extension 8 for the respective actuating rod 26.

It is also important in the present invention that the entire actuating slide 18 is covered and guided from all sides in the guide part 11, which guide part 11 is in turn held in the shuttle plate in the throat plate 2 and in the intermediate plate 37.

The entire thread clamping device 16 is thus protected against contamination.

Another important advantage of the present invention is that the entire actuating slide 18 is integrated with its actuating rod 26 in the throat plate 2 or in the intermediate plate 37 connected to the throat plate, which results in a compact, space-saving construction, in particular because the entire displacement movement in the plane of the needle plate 2.

The advantage of the present invention is therefore that an embroidery machine that can be switched off at a particular point can now be operated in a particularly advantageous manner. When the stitches on the needle side are switched off or the needles are manually stopped, the boats no longer need to be stopped in order to avoid the previously undesirable ones Avoid rubbing the rear or lower thread.

Now according to the present invention, all of the shuttle threads are first clamped and then cut on the shuttle side using the cutting and clamping device according to the invention. The shuttle threads cut in this way are then conveyed further into the clamping gap 17 according to the technical teaching of the present innovation, so that when the cutting device moves upward again, they can no longer be cut off again by this cutting device and, above all, cannot be detached. This has the advantage that the rear or lower thread is now clearly fixed in the throat plate in the area of the stitch hole 15 and can no longer be ground despite an oscillating movement of the shuttle 3. The defined fixation of the rear or lower thread in the area of the thread hole thus prevents the rear or lower thread from being chafed, even if the shuttle 3 still oscillates in the direction of the arrows 4.

The essence of the invention lies in the fact that a thread clamping and cutting device is arranged in the region of the tap hole, a clamping gap 17 of a thread clamping device 16 being arranged in the extension of the cutting direction for the cutting knife, so that the thread previously clamped by the cutting device and subsequently cut off is then cut is detected and fixed in the clamping gap 17 lying behind in the cutting direction.

With the arrangement of the thread clamping and cutting device directly in the area of the stitch hole 15, the advantage is achieved that the part of the rear or lower thread that remains on the fabric is cut extremely short.

It is also essential that the cutting device to be cut Thread is first transported without cutting in a clamping gap 17 and only cuts there and that after cutting off the cut back or bobbin thread is conveyed further up in the clamping gap 17 in order to then finally fix this thread.

In one embodiment, it is provided that the cutting device is displaceably guided in the region of a guide part 11 made of plastic, and essentially consists of a front plate and a rear plate, with a keyhole-shaped recess 22 with a bore 23 in each of the two plates 19, 20 and an elongated hole 24.

FIG. 2 shows a boat guide, various parts being covered for the sake of clarity. The middle part of Figure 2 shows all parts of a finished shuttle guide with thread clamping and cutting device integrated therein.

The right part of FIG. 2 shows the thread and clamping device according to the invention, the front wall of the shuttle guide being removed, and the left part of FIG. 2 shows the clamping device according to the invention, with the actuating slide 18 being removed.

The alignment of the keyhole-shaped recess 22 in alignment over the clamping gap 17 results in the advantage of better thread guidance into the clamping gap 17. The keyhole-shaped recess 22 in the front plate 19 and in the rear plate 20 is therefore not necessary for a solution; it is only important that the keyhole-shaped recess 22 lying clamping gap 17 is sufficiently long that the thread is clamped in the front region of the clamping gap and then cut and then transported further back into the clamping gap 17 by the cutting device.

The elongated hole 24 in the region of the keyhole-shaped recess 22 in the region of the front plate serves to prevent the cut thread 10 from being pushed out of the clamping gap 17 when the actuating slide 18 runs back.

The elongated hole 24 in the region of the recess 22 in the region of the rear plate 20 serves the same purpose.

Throughout the above description, the term "rear or bobbin thread" has been used as a synonym for "rear or bobbin thread".

However, the term “rear thread or bobbin thread” is only valid in connection with the working method according to the invention and the devices described, insofar as it is an embroidery machine with a shuttle.

The more general term "rear thread or bobbin thread" therefore refers not only to embroidery machines with corresponding shuttle and associated shuttle threads, but also to other embroidery methods such as double-chain embroidery machines and embroidery machines with round hooks.

DRAWING LEGEND

1

Fabric panel

2nd

Stitch plate

3rd

Boat

4th

Arrow direction

5

Thread hole

6

Boat guide 6a 6b

7

approach

8th

approach

9

feather

10th

Back thread or bobbin thread

11

Guide part

12th

approach

13

Recess
(Intermediate plate 37)

14

Locking bracket

15

Taphole

16

Thread clamping device

17th

Clamping gap

18th

Actuating slide

19th

Front panel

20th

Backplate

21

Recess

22

keyhole recess

23

drilling

24th

Long hole

25th

Cutting edge

26

Operating rod

27

screw

28

29

camp

30th

wave

31

Lever 31 '

32

Pivot point

33

Piston rod

34

cylinder

35

rail

36

37

Intermediate plate

38

Clamping fingers

39

Counter knife

40

Counter clamp

41

Arrow direction

42

Cutting edge

43

leg

44

Front surface

Claims (11)

1. A thread clamping and cutting arrangement for the rear- or lower thread of an embroidering machine, wherein a shuttle is slidably mounted in a shuttle guide and both a thread clamping device and a cutting arrangement are provided,
   characterised in that the cutting device is constructed in the form of the cutting blade with the cutting edge (25) independently of the thread clamping device (16) of the rear or lower thread, wherein the thread clamping and cutting device is arranged in the region of the stitch hole and in extension of the cutting device for the cutting blade, a clamping gap (17) of the thread clamping device (16) is arranged, wherein the thread previously clamped by the cutting device and subsequently cut off is engaged and fixed in the clamping gap (17) lying behind in cutting direction.
2. An arrangement according to Claim 1,
   characterised in that the clamping is initiated by its own actuating element, wherein the latter is subject to a movement independently of the cutting blade, and in so doing the cutting device conveys the thread which is to be cut firstly without a cutting process into a clamping gap (17) and only cuts it off there, and that after the cutting off has been effected , the cut off rear or lower thread is conveyed further upwards in the clamping gap (17) and is then finally fixed.
3. An arrangement according to Claims 1 and 2,
   characterised in that the cutting device is slidably guided in the region of a guide part (11) and consists substantially of a front plate (19) and of a rear plate (20), wherein in the front and rear plate (19,20) in each case a keyhole-shaped recess (22) is constructed with a bore (23) and an oblong hole (24).
4. An arrangement according to Claims 1 to 3,
   characterised in that the cutting blade formed by the front plate (19) with the cutting edge (25) itself is constructed as an actuating element for clamping.
5. An arrangement according to Claims 1 to 4,
   characterised in that the rear or lower thread is released from the clamping arrangement by the application of traction with the renewed start-up of the embroidering.
6. An arrangement according to Claims 1 to 5,
   characterised in that the cutting movement lies in the plane of the stitch plate.
7. An arrangement according to Claims 1 to 6,
   characterised in that the clamping arrangement (16) is arranged in the immediate vicinity of the cutting arrangement, wherein the cutting and clamping arrangement lies approximately in aligned opposite position to the stitch hole in the stitch plate.
8. An arrangement according to Claim 1,
   characterised in that the entire thread clamping and cutting arrangement is arranged in the stitch plate (2).
9. An arrangement according to one of Claims 1 to 8,
   characterised in that the front plate (19) is constructed so as to be movable with the cutting edge (25), whereas the counter-blade (39) and also the thread clamping arrangement (16) are constructed so as to be stationary.
10. An arrangement according to one of Claims 1 to 9,
    characterised in that the entire guide part (11), in which the cutting and clamping device are integrated, can be easily exchanged as a whole unit.
11. An operating process for the operation of an embroidering machine with a thread clamping and cutting arrangement for the rear or lower thread,
    characterised in that through the cutting process of the rear or lower thread, the clamping function of the clamping arrangement is not impaired, and that the cutting device conveys the yarn into the clamping device, but on further cutting processes no longer affects the clamping of the previously cut threads.

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