EP0014897B1 - Device for textile machines - Google Patents

Description

The invention relates to a device for feeding or returning the thread or threads on stitch, loop and / or stitch-forming textile machines using a thread roller or roller, which in the feed and take-off direction depending on a punch card control or a transport movement of the needles guiding the threads or other tools provided for stitch, loop and / or stitch formation is periodically driven and which keeps the thread or threads under frictional engagement by single or multiple loops, whereby the thread slides the roller is prevented.

In such textile machines, as a rule, continuously movable thread conductors are provided, each of which pulls the thread from the supply spool before a stitch or stitch is formed and, after the stitch formation, causes the thread to be pulled back and thus causes the stitch, loop or stitch to be tightened. To carry out these movements, a large number of reciprocating machine parts are required, as well as so-called thread brakes, since otherwise the thread guide would be pulled off the bobbin with each movement without any further effect. The constructive structure of a textile machine is quite complicated, particularly from this thread feeding point, and is therefore complex, which has a negative effect particularly in the maintenance work. In a special embodiment of this type (DE-B-1 929310), the threads run over a rotatably mounted brake roller, which are guided over deflection bodies arranged on this brake roller. Depending on the position of the brake roller, the wrap angle can therefore be reduced or increased. The brake roller can be rotated via an adjustment device which can be influenced by a punch card controller, depending on the stitch length, so that the thread brake surface covered by the threads is changed depending on the wrap angle. This changes the frictional force, i.e. the needle thread tension. The retraction path of the thread therefore depends on the thread tension. With appropriate thread tension, caused by the movement of the thread guide, the friction on the thread roller is overcome and the threads are retightened. An individual thread specification and an individual tightening of a stitch is not possible.

There is also known a thread-pulling method in shuttle embroidery machines (AT-B-71 977), the practical aim being to feed a decorative cord accordingly and to ensure that it never loosens or sags. Such a decorative cord has a tendency to curl up and form nodules even more than the simple embroidery thread. Therefore, the thread must never become loose or sag, so the thread must always be kept in an even and gentle tension. It is obvious that this condition must not apply to the embroidery threads with which the embroidery pattern is made, i.e. the threads passed through the needle, since there are periods of time during stitch formation in which the thread must not be tensioned . There could be no proper stitch formation in an embroidery machine if the thread were tensioned during the first short-stroke backward movement of the needles, since then no loop is formed for the passage of the shuttle. Such a measure may therefore be possible when using an ornamental cord, but this can never be transferred in the same way to the feeding and threading of the embroidery threads. In addition, in this known arrangement, only one forward and backward movement of a roller carrying the decorative cord is provided for all the stitches, the actual feed movement of the thread in turn being dependent only on the movement of the embroidery base, so that the entire load of the pulling of the decorative cord on the Embroidery base must be taken over. It is clear that the length of thread required due to the advancement of the embroidery frame must be reduced by quickly releasing the thread roller temporarily. For reasons of impracticability, it is therefore not possible to transfer such a thread tightening method to the actual embroidery threads, since the embroidery threads must not be under constant tension.

Furthermore, a thread feed device for multi-needle-gate embroidery machines is known (DE-C-692 218). As much thread should be fed for each individual stitch as corresponds to the stitch length. Nothing is said about the portion of the thread that is needed for the stitch formation itself, so that it is absolutely necessary to provide thread guides in this version too. Otherwise there would be no stitch formation and no appropriate stitch tightening. In a relatively complicated way, a possibility is shown here of how a feed movement for a thread roller could be derived from the gate drive shafts. This may prevent excessive thread tension while the threads are being pulled, but this does not bring any improvement, especially with embroidery machines, especially since only additional, complicated mechanical parts have to be installed without other parts being replaced. Predetermining the required thread length is not feasible here, since mechanical adjustment takes place as a function of the creel movement, so that the embroidery path and the threads themselves can be relieved only insignificantly. In any case, a reverse rotation of the needle roller is not possible with such an arrangement, so that stitch formation can only be carried out with the aid of thread guides.

Furthermore, a method and a device for tensioning the embroidery threads is known (CH-A-91 531), in which a thread roller is driven periodically in both directions of rotation depending on the needle movement or a punch card control and the thread is looped by one or more times with frictional engagement holds, preventing the thread from sliding on the roller. The retraction of the thread is dependent on the thread tension or the braking effect in this known construction because of the spring-loaded friction clutch. This thread roller moves practically after each forward movement against the force of a spring, so that this thread roller always tries to move back as soon as it is only to be fed further via a tooth pawl. It is therefore only possible in this embodiment to achieve a corresponding thread feed by pulling the thread from the base of the embroidery over the needle and the needle roller, since the thread roller itself is freely movable in this direction, with only the brakes provided counteract. There is therefore a further disadvantage that the retraction of the embroidery threads takes place under a particular load, that is against the force of springs, so that thread breaks and possibly needle breaks will very often occur. Furthermore, it is the case with such a configuration that only an equally large mechanical feed movement of the thread roller can be carried out, since a lifting disk sits on a camshaft, which can only move depending on the embroidery machine drive. With embroidery machines, there is an embroidery process for every revolution of the main shaft. The camshaft with the lifting disc will therefore rotate once during an embroidery process. Even if a corresponding translation were available, only a uniform feed movement could take place, which is also a hindrance here that the thread roller follows when the pawl moves downward, so that the pawl cannot therefore engage in other teeth at all. Seen from this point of view, this thread roller will only ever be in approximately the same forward and backward movement, with a corresponding forward movement also taking place for the thread feed. With such a design, it is therefore practically impossible to do without the usual thread guides.

The present invention has for its object to provide a device on textile machines, with which these disadvantages can be avoided and with which the thread or threads can be fed and retightened, and with which the stitches are tightened , Meshes or the like and thus a retraction of the thread or threads can be carried out to the desired extent.

According to the invention, this is achieved in that an electric or hydraulic actuator is provided for the drive of the thread roller or reel, which determines the feed path and the take-off path in each case independently of the thread tension, possibly changing from stitch to stitch in the path.

In the present invention, therefore, all forward and backward movements of the thread or threads can be controlled by a thread roller or thread rollers. A drive for the thread roller is therefore provided for both directions of movement independently of the thread tension, so that the preselected retraction path is always achieved independently of the thread tension. On the textile product itself, e.g. an embroidery path, there is no longer any stress from pulling the threads, and a number of heavy machine parts can be omitted (such as the large and small thread conductors and the corresponding drive elements). Already by default e.g. A corresponding thread feed can take place from the punch card control, whereby it is possible, for example, to carry out an additional thread feed for the stitch movement of the needle only immediately before the needle insertion, that an additional thread is added when a loop is formed and then of course a corresponding thread tightening after the stitch formation in the desired extent is made possible. The perfect thread tightening after stitch formation is an essential criterion for perfect embroidery goods and of course for any other perfect textile product.

Such a thread roller or reel also acts as a thread brake, so that the advancement and retraction when stitches or loops and stitches are tightened can take place without the thread or threads slipping. When using thread conductors that can be moved back and forth, on the other hand, the tensile force was transmitted both to the supply spool of the thread and to the textile product via the needle. The measures according to the invention therefore have an even more advantageous effect, particularly in the case of sensitive textile products or in the production of very fine patterns.

• Fig. eine schematische Darstellung der Fadenzubringung bei einer Stickmaschine, wobei die bislang üblichen Fadenleiter ebenfalls dargestellt sind;
• Fig. 2 eine Ausführungsform bei einer Stickmaschine, bei welcher die Fadenleiter nicht mehr aufscheinen.

Further features according to the invention and special advantages are explained in more detail using an exemplary embodiment in an embroidery machine. The drawings show:

• FIG. 1 shows a schematic representation of the thread feed in an embroidery machine, the thread guides that have been customary up to now also being shown; FIG.
• Fig. 2 shows an embodiment in an embroidery machine, in which the thread conductors no longer appear.

In Fig. 1, a thread roller 1 is shown, as is already available in a conventional arrangement in embroidery machines. This thread roller 1 is also called an emery roller. A thread 2 is drawn off from a corresponding bobbin 3 via this thread roller 1, the thread serving purpose moderately wraps the thread roller 1 once or several times so that a thread brake is achieved. The thread 2 then leads to a small thread conductor 4 and then back over the large thread conductor 5 to the needle 6. Before a stitch is formed, the thread 2 is withdrawn from the bobbin 3 by pivoting the thread conductor 4 and 5, since the other ends of the thread on the Embroidery web 7 are fixed, whereby the thread roller 1 is rotated by this movement. Since a relatively large loop is required during the stitch formation process, the large thread guide 5 is pivoted against the embroidery path 7, so that the thread 2 is completely loose and can form a large loop for the passage of the shuttle 8. After the stitch formation, the large thread guide 5 is again pulled back into its position shown in FIG. 1, so that the stitch is thereby attracted. In these known arrangements, the thread roller 1 is designed without a drive, but there is also a locking device which can optionally be used to lock the rotary movement of the thread roller 1. This possibility is used in the case of a desired particularly sharp tightening of the stitch.

According to the present invention, the thread roller 1 is now equipped with a drive, which can be actuated directly or indirectly from the punch card control in an embroidery machine.

Such an arrangement is particularly expediently feasible if the punched cards are read electrically or mechanically-electrically, in which case the control pulses are emitted from the punched card to a corresponding control device. Appropriate stepper motors, disc rotors or hydraulic motors for the gate drive are then actuated by this control device. Since the size of the embroidery hoop adjustment is given in such a control device, a corresponding thread advance can also take place during the movement of the embroidery hoop or even shortly before the movement of the embroidery hoop, so that there is a substantial reduction in the number of thread breaks. Just by pulling on as a result of pivoting the small thread conductor 4, there were relatively often corresponding thread breaks. In addition, there is the possibility that if the thread is too loose, it will twist itself, so that the thread will break again.

In existing embroidery machines, the thread feed can be converted in a simple manner by the thread or threads 2 continuing to be guided over the thread conductors 4 and 5, the movement of these thread conductors being stopped, however. The feeding, pulling and pulling back of the thread 2 then takes place only through the thread roller 1, the thread 2 being held in frictional engagement on the thread roller 1 by the single or multiple wrapping of the thread. By shutting down the thread conductors 4 and 5, not only is there a reduction in the drive line required for an embroidery machine, but also a substantial reduction in noise, since it is known that all the parts that go back and forth on such textile machines make up the major part of the noise pollution.

A significantly improved embodiment is shown in FIG. 2, which can be used in particular with new embroidery machines. Of course, this variant is also possible with old embroidery machines, since the thread guides can also be removed there if necessary. By eliminating such thread guides, the available space for the needle rail is considerably larger, this also playing an important role in particular in the arrangement of multicolor embroidery devices.

In the thread roller 1, a drive which can be actuated by the punch card controller is provided. In addition to the control from the punch card control, impulses are superimposed, which cause the thread roller 1 to run forwards and backwards. When stitch formation and thus when loop formation is required, a corresponding additional feed of the thread roller 1 is accomplished, the stitch being tightened subsequently after the stitch formation has ended by turning back the roller 1. The simplification that results from this is therefore of great value, since the small and the large thread guides 4 and 5 can practically be omitted. Furthermore, various control rods, drive elements for the thread guide and other machine parts are no longer required, so that in the case of new systems, the omission of these parts completely compensates for the need for an additional drive for the thread roller. This results in a simplification of the otherwise mechanically carried out control of the embroidery machine, a substantial reduction in the mechanical parts and thus a substantial reduction in noise. Furthermore, there are of course further advantages, since the monitoring of the threads becomes much easier and the threading itself is easier to carry out. By eliminating these mechanical parts directly in front of the embroidery path, there are also additional possibilities for arranging special additional devices.

The coil 3 can be arranged lying or standing upright, as can be seen from either FIG. 1 or FIG. 2.

In the case of multicolor embroidery, it would also be possible to arrange a plurality of thread rollers 1, for example, at an angle one above the other, the corresponding roller then being put into operation when the thread in question is used. It is also conceivable to guide each thread over a separate roller, which is then rotated by friction from a driven roller. When the reel or reels are lifted, the corresponding thread remains in the rest position. This arrangement is particularly useful for multi-color embroidery.

It has already been mentioned that a bulky item is provided in conventional embroidery machines thereby locking the thread roller when the stitch is particularly tight. This function of inserting the locking device also takes place from the punch card, and the control according to the present invention can be handled in such a way that when the locking device is used, the turning of the thread roller-1 is increased accordingly, so that the thread is pulled up is reinforced. As a result, the same punch cards can be used as before, the impulses now being passed on to the drive of the thread roller 1 in the corresponding control device instead of to the locking device. It can be seen from this that additional mechanical parts, that is to say the entire drive and the entire locking device, can be omitted.

The function of drilling occurs relatively often, especially with embroidery machines, i.e. corresponding holes are made in the embroidery base 7 through the drills, the edges of these holes then being subsequently embroidered. Since these drills are located below the needles, a corresponding path of the gate (i.e. the embroidery path) must be covered for the drilling process. When drilling, the thread is also to be kept correspondingly loose, so that with a command “drilling” an actuation impulse for driving the thread roller 1 is also derived from the punch card, so that, if necessary, a forward or backward rotation thereof before or after drilling he follows.

It is further proposed within the scope of the invention that the control device for driving the thread roller is assigned manually operable setting regulators which serve to enlarge or reduce the rotational movement of the thread roller 1 which is predetermined as a function of the punch card control. Then, for example, an impulse triggered by the punch card controller for a strong tightening of the stitch (blocking device on) can be further strengthened or weakened, so that an individual additional control possibility is given. Furthermore, fine settings for the feed and the retraction of the threads could also be achieved in this way, for example when drilling or during other additional work on the embroidery machine.

By means of the device according to the invention using the example of embroidery machines, different patterns can be produced very easily and in uniform quality, which is particularly important in the case of a terry pattern or, for example, a moss base. Loops of appropriate length should remain here even after stitch formation. This can only be achieved by the fact that the thread drop after the stitch formation is always uniform and precisely controllable.

Of course, such a device can be used in all types of embroidery machines without a difference in the type of punch card control.

The invention was explained using an exemplary embodiment in an embroidery machine. Of course, such a device is possible with all textile machines that provide stitch formation, loop formation or stitch formation in any form. It is also entirely possible, for example, to provide a corresponding thread roll on sewing machines, which feeds, pulls or retracts the thread depending on various movements (needle, presser foot, etc.). In the case of sewing machines, too, there are reciprocating parts in the form of thread guides, which can be omitted as a result. It is therefore also possible for the drive of such a thread roller or reel to be actuated in a manner other than as a function of a punch card control. For example, an operation depending on the transport movement of a textile product to be manufactured or processed, e.g. a fabric or the like. It is also possible to actuate the drive as a function of the transport and feed movement of the needles guiding the thread or threads or other tools provided for stitch, stitch and / or loop formation. In addition, actuation is possible in this connection as a function of a required tightening movement after a stitch or stitch formation, since the thread roller or spool must thereby be driven in one or the other direction of rotation. In the case of textile machines other than embroidery machines, additional, manually operable setting members are possible which, for example, allow the stitch or stitch to vary.

The device according to the invention brings about a substantial improvement and simplification of textile machines compared to the previously common arrangement of back and forth thread conductors, a large number of back and forth movable, relatively heavy machine parts are eliminated, the drive speed of the textile machines can thereby be increased further, and moreover there is a significant reduction in noise. Even when converting existing textile machines, there are significant advantages, since the previously provided, back and forth moving parts can simply be stopped, so that the advantages described are also fully realized.

Claims (2)

1. A device for the delivery and return of the thread (2) or threads on textile machines, which form stitches, loops and/or stitches by using a thread roller (1) or roll, which is driven periodically in the delivery and return direction in dependence on a punched card control or a transport movement of the needles (6) or of other tools (6, 8) provided for forming stitches, loops and/or stitches, guiding the threads, and which holds the thread or threads (2) by single or multiple looping in friction contact, the thread being prevented from sliding on the roller, characterized in that for the drive of the thread roller (1) or roll there is provided an electric or hydraulic adjustable drive which defines the delivery and the draw-off path in each case necessarily independently of the thread tension, and whose path, where appropriate, can be changed from stitch to stitch.

2. A. device according to claim 1, characterized in that there are associated with a control device, arranged upstream of the drive, adjustment regulators, which can be operated manually, for increasing or decreasing the rotating movement, of the thread roller (1) or roll, predetermined in dependence on the punched card control or a transport movement of the needles (6) or of other tools (6, 8) provided for forming stitches, loops and/or stitches, guiding the threads (2).

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