KR20130009991A - Single-head or multi-head embroidery machine having a two-thread lockstitch rotary looper - Google Patents

Abstract

The present invention relates to a stitch forming machine having needle stitch forming tools formed by a yarn guide needle interacting with a dual stitching loop to form needle stitches in each case and having a feeding device for obtaining relative movements between the embroidery material and the stitch forming tools And wherein the relative movements occur in dependence on the movements of the needle, wherein the relative movement occurs in response to the movement of the needle, and between the feed motion of the embroidery material and the needle swapping phase The two-thread main loop looper rotates at a rotational speed corresponding to n times the rotational speed of the main shaft of the machine, where n is an integer greater than the number 2.

Description

HEAD OR MULTI-HEAD EMBROIDERY MACHINE HAVING A TWO-THREAD LOCKSTITCH ROTARY LOOPER WITH 2-

The present invention relates to an embroidery cloth having stitch forming tools formed by a yarn guide needle interacting with a double-lock-stitch looper to form needle stitches in each case, To a single or multi-head embroidery machine, which also has a feeding device for obtaining relative movements between the tools.

The dual-purpose looper most of the time used in this case is a rotating looper that has been employed several hundred times in thousands of times as a "standard looper" in a sewing machine, and here it performs two complete rotations per needle-forming period, . These double-purpose looper require a certain amount of thread tension for needle sweat formation, especially for needle swab insertion.

On the one hand the sewn seam and on the other hand the other purpose of the embroidered seam is the basis for a substantial difference between the requirements of the sewing machine and the requirements of the embroidery machine. Whereas a sewing essentially represents a connecting or fixing seam which reliably connects two or more parts with each other, the embroidery seam represents an ornament (decorative seam) applied to the embroidery crepe and does not transmit any force at all .

The strength of this stationary seam is such that the thread loop that is dropped by the looper is centered on the layers of material in such a way that the needle thread and the knotting of the looper thread are stitched together, Is pulled by a thread lever with a relatively large force toward the part. The actual force of the looper thread must also be calculated accordingly.

The conditions in the formation of embroidery seams are completely different. In such a case, while the needle thread (embroidery thread) is intended only to be laid cleanly on the upper side of the embroidery material in order to obtain a decorative effect, loose thread elements And the yarn tension during the embroidery process is kept as low as possible so that the knot between the needle thread and the looper thread is always placed on the underside of the embroidery crepe.

For this reason, a much lower tension of the needle thread is desirable for an embroidery machine as compared to a sewing machine.

Since the kinematics of the double-boned looper are not adjusted in an appropriate manner when the double-boned looper performing two turns per needle-forming period is delivered into the embroidery machine, even in the current embroidery machine, The feeding motion is initiated when the needle sweat forming process has not yet been completed. As a result, this is very disadvantageous because, when the threading machine begins to pull the thread, the embroidery thread has already moved by a significant amount relative to the position when the needle is inserted into the embroidery thread. As a result, the circumference (limb) of the thread loop from the needle stitch hole to the needle store experiences, in each case, both when the needle comes out of the stitch hole and immediately after passing through the embroidery thread. The two refractions cause additional resistance when the thread is pulled by the thread, and this additional resistance inevitably leads to an unnecessary increase in the minimum amount of thread tension.

This situation has a particularly disadvantageous effect on the entire embroidery machines as compared to a sewing machine, since the embroidery machines operate in feed directions extending in different directions than generally much longer stitch lengths.

It is therefore an object of the present invention to create a solution which enables the minimum yarn tension in an embroidery machine with dual-purpose rotating loops to be maintained in a very low area, which is desirable.

The present invention relates to a double-boned looper embroidery machine, in which needle-stitch forming is not yet completed, i.e., when the needle thread has not yet been fully drawn by the threader, the feeding motion of the sewing material has already begun, On the one hand, the knowledge that the sewing material at least partially overlaps.

In order to achieve the above-mentioned object, it is proposed to have a dual-purpose looper rotating at a rotation speed corresponding to n times the rotation speed of the main shaft of the embroidery machine, in order to avoid temporary overlap between the needle- Where "n" is an integer greater than "2 ".

Due to the fact that the double-boned looper rotates for example to "n = 3 ", the needle sweat formation (with respect to the angle of rotation covered by the embroidery machine spindle) is achieved by a method corresponding to the greater angular speed of the double- In the case of a double-boned looper rotating at "n = 2 ". Therefore, the time window in which the needle sweat formation and the supplying motion of the embroidery felts are simultaneously activated is minimized.

Since the double loop looper rotating twice per needle sweat forming period produces absolutely satisfactory results in the known fields as a high speed sewing machine with a very fast rotating speed, an increase according to the invention in the rotational speed of the double loop looper is achieved It is clear that neither the quality of the seam nor the mechanical strength is adversely affected.

In the above solution, while the double boning looper rotates at a constant rotational speed that is "n times" the rotational speed of the main shaft of the machine, the object of the present invention is to provide a machine- Wherein the angular velocity of the dual-purpose looper has a larger value during its working rotation, in contrast to a smaller value during its idling time.

The invention will be described in more detail below with reference to the corresponding drawings and exemplary embodiments.

1 is a partial cross-sectional view of a front region of a conventional embroidery head having a double-boned looper.
Figure 2 is a displacement / time graph of the movement of the supplying device and needle sweat-forming tools according to the prior art, with a time window overlapping temporally for needle swab formation and dispensing movement.
Figure 3 is a displacement / time graph of movement of the needles of the needles and the feeding device according to the present invention.
Fig. 4 shows a situation of a yarn loop passing through a torque support of a bobbin case holder of a double-boned looper corresponding to the time window 31 in Fig. 2 according to the prior art; Fig.
Fig. 5 is similar to that shown in Fig. 4, but showing the different directions of the feeding motion of the embroidery frame;
6 is a view showing a state of a yarn loop passing through a torque supporting portion (stopping piece) of a bobbin case holder of a double-boned looper corresponding to the time window 31 in Fig. 3 according to the present invention.

1 shows a cross-sectional view of a front part 1 of a conventional embroidery head having a double-boned looper 2, an upper table 3 and a needle-stitch plate 4. The embroidery frame 5, which can freely move in two axes and to which the embroidery thread is clamped, is placed on the upper table 3. The double-purpose barrel looper 2 is of conventional design and has a bobbin case holder 6 for receiving the bobbin case 7. The bobbin accommodating the looper chamber storage portion is rotatably mounted on the bobbin case 7. [

The needle bar 9, which interacts with the double-purpose barrel looper 2 and supports the needle 8, is held in such a manner that it can vertically move in the base frame 10, and the driving movement of the needle- Is driven in a manner known per se by the driver (11) which delivers it to the controller (9). A holding-down device 12 is also provided per embroidery thread in the front part 1 of the embroidery head, the suppression device is arranged in a displaceable manner on the needle bar 9 and is driven by a driver 13 do. A thread take-up 14 driven in a known manner and pivotally mounted on a shaft 15 is arranged per embroidery thread in the front part 1 of the embroidery head and the thread take-up machine is in turn housed in the basic frame 10. Finally, the embroidery head has a yarn brake 16 which can be adjusted in a known manner and is fitted in a fixed manner on the front part 1.

The rear part of the embroidery head, which is not shown in detail, is fixedly connected to the machine frame and has actuators for the needle bar 9, the suppression device 12 and the thread take- The rear part of the embroidery head is also connected to the front part 1 via a linear guide which is not shown in more detail so that the front part 1 is arranged in the alignment direction of the needle bars 9 available on the double- And in each case the needle bar 9, the restraining device 12 and the thread take-up 14 are connected to the respective driving parts.

Except for the driving part of the double-purpose barrel looper 2, the above-mentioned parts are driven by a machine spindle (not shown) which performs one complete, 360 ° rotational motion per needle sweat forming period. In the conventional technique, the double-boned looper 2 rotates at a double rotation speed, i.e., "n = 2" " Thus, in the illustrated exemplary embodiment of the invention, step-up gearing with a step-up ratio of "n = 3" / RTI >

In order to understand the present invention, it will be appreciated that, among other things, the known kinematic interaction of the double-boned looper 2 and the needle 8 rotating twice in accordance with the prior art, and also with a feeding device (not shown) during one revolution of the machine spindle And FIG. 2, which illustrates a typical motion diagram of the suppression device 12. As shown in FIG.

The graph 17 is shown as the movement of the tip of the needle 8 relative to the surface of the needle sweat plate. At time 18, the needle tip descends below the surface of the needle sweat plate 4 through the needle stitch hole, and at time 19, the needle tip rises over the needle stitch plate again.

The graph 20 shows the lifting motion and distance of the underside of the restraining device 12 above the needle sweat plate 4. [

The graph 21 shows the progression of the embroidery frame movement to the final needle insertion point on the embroidery crepe at time 18.

The embroidery frame begins to move at a time 22 and therefore immediately after a time 19 corresponding to the time the needle 8 exits from the needle-stick plate 4. [ The embroidery frame stops moving at the end of the plot.

All values of this motion function are linearly scaled as a constant factor by a variable stitch length (= distance of the final insertion point 18 to a future needle insertion point).

The graph 23 shows the therad requirement of the needle 8 starting at time 24 as the eye of the needle descends below the surface of the embroidery crepe. At time 25, the end of the double barrel looper 2 passes into the needle thread loop formed by the needle 8, so that the double barrel looper 2 takes control of the needle thread. The actual requirement is illustrated by graph (26). The end of the double-purpose barrel looper 2 is firstly widened by the needle 8 to the yarn loops provided to the double-loop looper 2, and then the yarn loops are guided around the bobbin case 7 arranged inside the double- do. The thread requirement of the double-purpose looper 2 then decreases again until the looper completely looses the needle thread at time 27. The double main barrel looper 2 thus contacts the needle thread only at the time between the time points 25, 27. This corresponds to at most 180 [deg.] Out of 360 [deg.] In the needle-stitch forming period; In the remainder of the time, the double-purpose looper 2 is revolved, that is, the double-boned looper 2 does not come into contact again with the needle thread until the continuous needle-stitch forming period.

The yarn requirement of the needle 8 and the standing opposite to the double barrel looper 2 are yarn feeds corresponding to the graph 28. The thread feed is a function of the pivot position of the thread take-up 14 about its axis 15. The yarn feed according to graph 28 has an excess amount compared to yarn requirement 23,26. This can be used as a stockpile, from which needle stitch length dependent yarn consumption is taken from previous needle sweat cycles.

The yarn feed 28 is reduced by the amount of this yarn consumption, and so the effective yarn feed is the same as the graph 29. [ The thread consumption is taken only from the needle chamber storage by the thread take-up 14 during the time period between the time 30 and the picking TDC. In this process, the system thread length (= (The entire length of the needle thread between the needle thread 4 and the needle thread 4) is again equilibrated at the highest turning point of the thread take-

The length of the time window for the movement of the embroidery frame is different from that of the serving machine. In the case of a sewing machine, this is approximately 120 [deg.]. However, in the case of a looper embroidery machine, this is 180 ° or more. The embroidery frame starts moving at time 22, and therefore is carried over correspondingly in time in the prior art. Although this is the concession required for a numerically controlled embroidery frame, regardless of the embroidery machine, it leads to considerable drawbacks with respect to embroidery with respect to the amount of yarn tension required.

The bringing forward at the time of the start of the displacement movement of the embroidery frame within that period before the end of the thread insertion by the thread take-up 14 to complete the disclosed needle stitch, (4).

A radially oriented groove 34 is provided on the bobbin case to fix the bobbin case holder 6 against rotational movement and a stationary stop piece 35 having a nose is coupled into the groove, , It can be seen in Figure 4 that the needle thread can move through between the stop 35 and the side border defining surface 36 of the groove 34.

The final insertion point of the needle 8 is larger than 1 mm from the center of the needle pit hole at time 18 by the movement of the embroidery crepe along the graph 21 in the time domain 31 in the case of a needle stitch length longer than 2 mm Two deflections 32, 33 (Fig. 4) of the needle room occur in the path between the thread take-up 14, the groove 34 and the stop piece 35, if displaced. The actual force (F1) from the area of the needle thread above the embroidery thread to the thread is reduced by two steps, first at the refraction (32) and then again at the refraction (33). What remains is force (F2). This is the force required to open the thread passage between the stop 35 and the side boundary crystal surface 36 of the groove 34. [

The magnitude of the force F2 is predetermined by the stitch forming process and therefore can not be changed. In order for the force to reach the predetermined value again by the system, the actual force F1 must be raised by a factor of approximately "K" even in the case of pairs of material having appeal. In the case of non-appealing material pairs (cotton / cotton embroidery crepe), this factor "K" The increased actual force F1 in this way corresponds to the minimum holding force of the yarn brake 16 when the yarn is pulled by the yarn drawer 14. [

Figure 5 shows the conditions for the time window 31 in which the thread take-up 14 is pulled out of the yarn loops and the nose of the stopping piece 35 and the lateral boundary defining surface 36 of the groove 34, And the supply motion of the embroidery cochlear to the supply in Fig. 4 is reversed and occurs in the direction of the arrow in Fig. This roughly corresponds to what happens to be known as loop loops during sewing or embroidery. In this case, the needle thread is looped not only by the looper chamber 37 but also by itself. In the case of a sewing machine, this conveying direction and situation hardly occur.

However, in the case of looper embroidery machines, this happens regularly. A more intense loop at the real refracting point 32 further increases the factor "K ". If the needle thread loop has passed through the thread passage, the needle thread tension actually drops to zero. The thread take-up 14 further reduces the size of the needle thread loop until it is completely minimized at the point of view 30. On the way to this point, the needle chamber portion 38, which has been laid flat on the embroidery thread, has been formed by itself and the thread loop 40 protruding above the embroidery phosphorus by the friction of the needle thread at the knot 39. This loop of loops 40 must be pulled back in time period 30 to the take-off (TDC). All of this is more successful, and the more abrupt the needle room portion 41 becomes the eye of the needle, in this case leaving the surface of the embroidery crepe. This steepness decreases with trigonometry along with the path of the embroidery thread transport covered to this point (according to graph (21), this is already 75% of the stitch length). Depending on the coefficient of friction of the needle thread used, it is only possible to pull the thread loop 40 safely up to the associated maximum needle stitch length.

4 and 5, the situation of increasing the required seal tension is such that the actual passage between the stopping piece 35 and the lateral boundary crystal surface 36 of the groove 34 is at the present moment of the embroidery crepe But only in the middle of the advanced supply movement. This is the result of temporary overlap between looper activities or needle sweat formation due to the activities of the embroidery wrapping or feeding device.

It is therefore clear that the carry over from the beginning of the feeding movement of the embroidery frame into the temporary area of pulling of the needle thread by the thread take-up 14 leads to an undesirable increase in the seal tension. However, this is not exactly desirable in an embroidery machine.

The diagram of the motions of the needle-stitch forming tools shown in Fig. 3 in accordance with the present invention is based on the movement of the double-boned looper 2, and in addition to the process of the graphs 26, 28, and 29 depicting the actual requirements and thread unwinding Corresponds to the graph according to Fig.

Because of the fact that the double boning looper rotates for example to "n = 3 ", the needle sweat formation (with respect to the rotation angle covered by the machine spindle) rotates to" n = 2 " Which occurs faster than in the case of a double-boned looper. This is achieved by loosening (in relation to the rotation angle of the machine spindle) by the double-purpose looper 2 at a faster time than the double-looped looper in which the yarn loop is rotated twice, Quot; means that it is displaced toward the left in the diagram according to FIG. 3 compared with its position in the diagram according to FIG.

In this way, the movement of the thread take-up 14, which pulls the loop of formed needles and looper threads, can correspondingly start at a faster time (relative to the rotational angle of the machine spindle), so that the thread take- (TDC) of the movement path more quickly, and therefore, the needle stitch formation is correspondingly terminated (faster with respect to the rotation angle of the machine main axis) correspondingly.

Therefore, the needling formation and supply are released in a timely manner. The result shows the situation of the yarn loop just before the take-off (TDC) when the remainder of the yarn loop passes through the thread path between the stopper 35 and the side boundary crystal surface 36 of the lobe 34 Is shown in Fig. The resistance overcome in the process by thread represents the system-required minimum yarn force (= tension) when the rotating looper is used.

In comparison with Figures 4 and 5, there are no longer any actual refraction points on the needle sweat plate and around the embroidery fissure, and around the actual loop moving towards the needle. Thus, the previously required increase in yarn retention by a factor of 2.5 to 4 with respect to the high frictional force, and therefore the minimum yarn force, is also dispensed due to the omission of real refractions. Therefore, the present invention enables the operation of the looper embroidery machine with a yarn tension that is only slightly higher than the system-required minimum tension, for reasons of functional reliability of needle-stitch formation.

Claims (3)

Further comprising a needle-puck forming tool formed by a yarn guide needle interacting with a dual-purpose looper to form needle pads in each case, and also having a feeding device for obtaining relative movements between the embroidery material and the needle-puckering tools, Wherein relative movements occur in dependence on movements of the needle, in a single or multiple head embroidery machine,
In order to reduce the temporary overlap between the stitch forming phase and the feeding motion of the embroidery material, the double-purpose looper rotates at a rotational speed corresponding to n times the rotational speed of the main shaft, where "n" Characterized in that it is a large integer. Further comprising a needle-puck forming tool formed by a yarn guide needle interacting with a dual-purpose looper to form needle pads in each case, the apparatus further comprising a feeding device for obtaining relative movements between the embroidery material and the needle-puckering tools, Wherein relative movements occur in dependence on movements of the needle, in a single or multiple head embroidery machine,
Characterized in that in order to avoid a temporary overlap between the needle-stitch forming phase and the feeding motion of the embroidery material, the double-purpose looper rotates at an angular speed which can be changed periodically with respect to the angular speed of the main shaft. The method according to claim 1,
Characterized in that a step-up gear transmission having a step-up ratio of 1: 3 is arranged between the machine spindle and the double-purpose barrel looper (2).

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