Abstract
In order to better configure a ribbon needle weaving loomin particular for applications in which there are particular requirements for the setting of the weft thread tensionit is proposed to provide an electromechanic actuator for driving the weft insertion needle and a control device. Thereby, the actuator is configured in such manner as to allow preselection, by means of said control device, of the end position at weft insertion and of the position with retracted weft insertion needle and/or preselection of the starting time point of the motion of the weft insertion needle and/or preselection of the instantaneous speed of the motion of the weft insertion needle, within a certain range.
Claims
1. A ribbon needle weaving loom comprising a weaving point, at which warp threads are interweavable to each other by means of at least one weft thread a device for feeding the warp threads, a device for feeding the at least one weft thread, further comprising a shed forming device for forming a shed from the warp threads, further comprising at least one weft thread insertion needle for inserting a weft thread loop into the shed, and comprising a reed for stopping the weft thread loop, wherein an electromechanic actuator for driving the weft thread insertion needle and a control device are provided, characterized in that the weft thread insertion needle beim weft insertion and die Position bei the actuator is configured in such manner as to allow preselection, by means of said control device, of the end position of the weft thread insertion needle at weft-insertion and of the position with retracted weft-insertion needle and/or preselection of the starting time point of the motion of the weft-insertion needle and/or preselection of the instantaneous speed of the motion of the weft-insertion needle, at least within a certain range.
2. The ribbon needle weaving loom according to claim 1, characterized in that the electromechanic actuator is configured as rotary actuator, preferably as servo motor or as stepper motor.
3. The ribbon needle weaving loom according to claim 2, characterized in that the weft thread insertion needle is firmly connected to the axis of the rotary actuator.
4. The ribbon needle weaving loom according to claim 2, characterized in that the weft insertion needle is connected to the axis of the rotary actuator through a band or pulley drive or a crank drive.
5. The ribbon needle weaving loom according to claim 1, characterized in that the electromechanic actuator is configured as a linear actuator.
6. The ribbon needle weaving loom according to claim 5, characterized in that the weft thread insertion needle is fixedly connected to the lifting axis of the linear actuator.
7. The ribbon needle weaving loom according to claim 5, characterized in that the weft thread insertion needle is connected to the linear actuator through a band or pulley drive, a pushrod, a pinion or a lever drive.
8. The ribbon needle weaving loom according to claim 1, characterized in that the actuator and the weft thread insertion needle form, together with a restoring spring arrangement, a spring/mass system.
9. The ribbon needle weaving loom according to claim 1, characterized in that the weaving loom is equipped with means for producing a ribbon with varying width.
10. The ribbon needle weaving loom according to claim 1, characterized in that the weaving loom is configured in such manner that the weft thread insertion needle is equipped with means for receiving and depositing weft threads of various type.
11. The ribbon needle weaving loom according to claim 1, characterized in that the weaving loom is configured in such manner that additional threads, such as effect threads or antenna threads, are introduceable by means of a reed hook or a substantially equivalent means into the woven material and that the control device is configured in such manner that the weft thread insertion needle and the reed hook or the substantially equivalent means remain unaffected by the weft thread insertion needle.
12. The ribbon needle weaving loom according to claim 1, characterized in that the control device is part of a control loop, wherein a rotation angle measuring device is provided at the axis of the weft thread insertion needle, which provides comparison with a target rotation angle and is used to control the actuator.
13. The ribbon needle weaving loom according to claim 2, characterized in that the actuator and the weft thread insertion needle form, together with a restoring spring arrangement, a spring/mass system.
14. The ribbon needle weaving loom according to claim 2, characterized in that the weaving loom is equipped with means for producing a ribbon with varying width.
15. The ribbon needle weaving loom according to claim 2, characterized in that the weaving loom is configured in such manner that the weft thread insertion needle is equipped with means for receiving and depositing weft threads of various type.
16. The ribbon needle weaving loom according to claim 2, characterized in that the weaving loom is configured in such manner that additional threads, such as effect threads or antenna threads, are introduceable by means of a reed hook or a substantially equivalent means into the woven material and that the control device is configured in such manner that the weft thread insertion needle and the reed hook or the substantially equivalent means remain unaffected by the weft thread insertion needle.
17. The ribbon needle weaving loom according to claim 2, characterized in that the control device is part of a control loop, wherein a rotation angle measuring device is provided at the axis of the weft thread insertion needle, which provides comparison with a target rotation angle and is used to control the actuator.
18. The ribbon needle weaving loom according to claim 4, characterized in that the actuator and the weft thread insertion needle form, together with a restoring spring arrangement, a spring/mass system.
19. The ribbon needle weaving loom according to claim 4, characterized in that the weaving loom is equipped with means for producing a ribbon with varying width.
20. The ribbon needle weaving loom according to claim 4, characterized in that the weaving loom is configured in such manner that the weft thread insertion needle is equipped with means for receiving and depositing weft threads of various type.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] Further details, advantages and features of the object of the present invention will become apparent from the following description and the corresponding drawings, in which ribbon needle weaving looms and their weft thread insertion units according to the present invention are illustrated by way of example. In the drawings there are shown in:
[0007] FIG. 1 a weft thread insertion unit according to a first embodiment of the invention with a rotary actuator directly connected to the weft insertion needle, in the position open shed;
[0008] FIG. 2 a weft thread insertion unit according to the embodiment in FIG. 1, in the position reed beat-up;
[0009] FIG. 3 a weft thread insertion unit according to a second embodiment of the invention with a rotary actuator connected to the weft insertion needle by means of a toothed belt, in the position open shed;
[0010] FIG. 4 a weft thread insertion unit according to the embodiment in FIG. 3, in the position reed beat-up;
[0011] FIG. 5 a weft thread insertion unit according to a third embodiment of the invention with a rotary actuator connected to the weft insertion needle by means of a crank drive, in the position reed beat-up;
[0012] FIG. 6 a weft thread insertion unit according to the embodiment in FIG. 5, in the position open shed;
[0013] FIG. 7 a weft thread insertion unit according to a further embodiment of the invention with a rotary actuator connected to a plurality of weft insertion needle by means of a toothed belt, in the position reed beat-up;
[0014] FIG. 8 a weft thread insertion unit according to an alternative embodiment of the invention with a linear actuator directly connected to the weft insertion needle, in the position open shed;
[0015] FIG. 9 a weft thread insertion unit according to the embodiment in FIG. 9, in the position reed beat-up;
[0016] FIG. 10 a weft thread insertion unit according to a further embodiment of the invention with a linear actuator connected to a plurality of weft insertion needles by means of a pushrod, in the position reed beat-up;
[0017] FIG. 11 a weft thread insertion unit according to a further embodiment of the invention, in which the actuator and the weft thread insertion needle form, together with a restoring spring arrangement, a spring/mass system;
[0018] FIG. 12a the tension situation of the weft thread (weft thread triangle) according to FIG. 1 at the left turning point;
[0019] FIG. 12b the tension situation of the weft thread (weft thread triangle) according to FIG. 8 at the right turning point;
[0020] FIG. 13a the weft thread feed situation at different locations,
[0021] FIG. 13b the diagram of the weft thread position () over the phase () of the weaving process (main shaft),
[0022] FIG. 13c the diagram of the weft thread consumption over the phase () of the weaving process (main shaft), and
[0023] FIG. 13d the diagram of the weft thread tension (F.sub.s) over the phase () of the weaving process (main shaft);
[0024] FIG. 14a the diagram of the weft needle position (x)relative to the right-end pointover the phase () of the weaving process (main shaft) with a delayed thread insertion of the weft insertion needle and
[0025] FIG. 14b the diagram of the shed opening () over the phase () of the weaving process with the normal shed insertion phase angle (.sub.1) and with the delayed thread insertion phase angle (.sub.2) of the weft needle according to FIG. 14a;
[0026] FIG. 15a-n a weft thread insertion unit with a device for a weft thread change in various process states,
[0027] FIG. 16a-e a weft thread insertion unit which is adapted for wide/narrow weaving of ribbons; and
[0028] FIG. 17 the control loop of a weft thread insertion unit with a controlled actuator.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
[0029] In FIGS. 1 and 2, there is shown a first embodiment of the present invention by means of the essential elements. In the position open shed (FIG. 1), a weft thread insertion needle 10 is inserted into the open shed 8 with warp threads 4 by means of a rotary actuator 30 directly connected to the weft insertion needle 10, while in the position reed beat-up (FIG. 2) the weft thread insertion needle 10 is removed from the woven material 9 by means of the rotary actuator 30, the reed 20 is stopped against already woven material 9 and the shed 8 is closed. It will readily be understood that the rotary actuator will execute an oscillating motion in the present case. A comparison of these two figures shows that each weft thread forms a respective weft thread triangle between the weft thread guiding eye 14a, the last weft thread loop 10b and the thread receiving 10a at the weft thread insertion needle 10 in the two positions shown. In the case of a single weft thread shown here, the thread receiving 10a is also an eye. This triangle, which in each case degenerates to a line at a certain position of the weft thread insertion needle 10 in the shed 8, will be the subject of further discussion of the present invention and its execution. First, however, certain variations to the embodiments shown in FIGS. 1 and 2 shall be described. In the FIGS. 3 and 4, the direct drive has been replaced by a toothed belt of a band or pulley drive 34. This can have reasons regarding a certain, advantageous transmission or reducing ratio, that is, in the configuration of the rotary actuator 30, or else regarding the available spatial conditions. Again, the rotary actuator 30 will execute an oscillating motion. In the FIGS. 5 and 6, the direct drive has been replaced by a crank drive 36. In this case, the rotary actuator 30 can be set up and operated so that it cannot execute an oscillating motion, but a circular motion. In FIG. 7, there is shown a weft thread insertion unit according to a further developed embodiment of the invention with a rotary actuator 30 connected to a plurality of weaving units, which are arranged adjacent to each other, each having one weft thread insertion needle 10, by means of a pulley drive 34 with toothed belts, in the position reed beat-up. However, the rotary actuator 30as shown in FIGS. 8 to 10can be replaced by a linear actuator 30a. FIG. 8 shows such a weft thread insertion unit with a linear actuator 30a directly connected to a plurality of weft insertion needles by means of a pushrod in the position reed beat-up, and in FIG. 9 in the position reed beat-up. FIG. 10 shows a weft thread insertion unit with a linear actuator 30a connected to a plurality of weft insertion needles 10 by means of a pushrod 38, in the position reed beat-up. In FIG. 11, there is shown an embodiment in which the actuator 30a and the weft thread insertion needle 10 form, together with the two restoring springs 52 and 54 of a restoring spring arrangement 50, a spring/mass system. If the latter is displaced by a path A from the equilibrium position and then released, it oscillates in its natural frequency .sub.0. The shape of motion corresponds to a pure sine curve:
s(t)=A*sin(.sub.0*t) A=oscillation amplitude [m], t=time [sec]
Frictional forces dampen the vibration, so that it subsides and finally comes to a standstill. The natural frequency substantially depends on the moving mass and the spring constant and is calculated according to the formula:
.sub.0.sup.2=c/m c=spring constant [N/m], m=total moving mass [kg]
Ideally, the system is tuned such that the frequency of the main shaft rotation in the production mode coincides with the natural frequency of the weft insertion system. The linear actuator 30a then only has to overcome the frictional forces and to correct small frequency deviations. In this way, a very low-energy operation of the weft insertion system is possible. As soon as the main shaft rotational frequency falls below the natural frequency of the weft insertion system and/or the shape of the motion of the weft insertion system shall deviate from the pure sine curve, the linear actuator must apply higher forces for the synchronization of the motions because it must counteract or support the natural frequency. Provided that the friction in the vibration system is not excessive, the maximum force to be applied by the linear actuator F.sub.max=c*A occurs when the weft needle must be held in one of its end positions when the machine is stopped.
[0030] In FIGS. 12a and 12b, the above-mentioned weft thread triangle will now be explained. The weft thread 14 is feed to the weft thread guiding eye by means of the weft thread transport means 18 via the eye 18a and the weft thread tension spring 18b. In FIG. 12a, there is shown the weft geometry during the motion of the weft thread insertion needle 10 out of the shed. The minimum weft tension occurs when the weft thread eye (at position B) crosses the line segment A (position of the weft thread guiding eye 14a)-D (position of the knitting of the weft thread 14 at the right ribbon edge) at the point B, that is where the triangle degenerates to a line. The maximum weft thread tension, on the other hand, occurs when the weft thread insertion needle 10 reaches the left turning point or stops at the reed. From the difference of the distances A-B-C-D to the distance A-D there results the extent of this maximum tension. In FIG. 12b there is shown the contrasting situation of the weft thread geometry during the motion of the weft needle into the shed. The minimum weft thread tension occurs when the weft thread eye crosses the line segment A-E (with E as the position of the left ribbon edge). The maximum weft thread tension occurs when the weft needle reaches the right turning point. The difference of the distances A-B-E to the distance A-E here pertains to the extent of this maximum tension. The situation of the weft thread feed at various positions, namely I.sub.t behind the weft thread transport means 18, I.sub.s at the weft thread tension spring 18b and I.sub.v next to the weft thread guiding eye 14a, is shown geometrically in FIG. 13a and as a diagram above the phase angle of the weaving cycle (main shaft) in FIG. 13c. The corresponding weft needle position results from the diagram of FIG. 13b and the tension F.sub.s from the diagram of FIG. 13d.
[0031] This situation is now accessible to the improvements of the present invention, which will be shown in various applications.
[0032] As a first application example, the delayed shed insertion angle of the weft thread insertion needle 10 will be explained with reference to FIGS. 14a and 14b. If the weft thread insertion needle 10 at the point .sub.2/.sub.2 inserts into the shed 8 later than the normal insertion .sub.1/.sub.1, the shed is already opened further. This is advantageous for warp threads that tend to cling. The farther the shed opens, the higher the warp thread tension and the sooner the cling of the upper and lower shed threads is released. Moreover, in the case of a delayed insertion of the weft thread insertion needle 10 into the shed 8, more time is available.
[0033] In the end, the security against understitchingthat is, an insertion while a warp thread is still in a wrong position, which results in a weaving faultis significantly increased. Even more significant is the advantage for a stitching weaving loom comprising, for example, a reed hook for the insertion of additional threads. In such a stitching weaving loom, the stitching needle must be immersed into the lower shed before the weft needle inserts into the shed. Since the immersion movement of the stitching needle is very time-critical (high accelerations), a delayed insertion of the weft needle allows for higher speeds.
[0034] As a further application example, the weft thread change will be explained with reference to FIGS. 15a to 15n. Thereby, FIGS. 15a, 15c, 15e, 15g, 15i and 15k show each one of the weft thread situations from above and FIGS. 15b, 15d, 15f, 15h and 15 show each one of the weft thread situations from the side, while FIGS. 15l-n show the corresponding thread tension over the phase angle of the weaving loom. FIGS. 15a to g show a weft thread change from the weft thread of the thread guide (eye) A1 to a weft thread of the thread guide A2. In the FIGS. 15a and b, the thread guide A1 is in the high position and remains in this position as long as the weft thread 14 shall be inserted. In the FIGS. 15c and d, the weft thread 14 remains in the weft needle fork 19 when the latter crosses the line segment A1-D, since it is pulled into the fork as long as the thread guide A1 remains in the high position. In the FIGS. 15e and f, there is shown thatas soon as the weft needle fork 19 moving out of the shed 8 has crossed the line segment A2-Cthe thread guides A3 and A4 change from high to low position and from low to high position, respectively. Thus, the corresponding weft threads 15 and 17 are not inserted into the weft needle, but rather are incorporated into the left ribbon edge as normal warp threads. The thread guide A2 remains in the low position because it shall insert the weft thread No 2 into the weft needle fork in the next cycle. The FIGS. 15g and h show that the thread guide A1 moves from high to low position when the weft needle starts its backward movement. As soon as the weft needle fork crosses the line segment A1-D, the weft thread 14 drops, therefore, out of the fork into the lower shed. The thread guide A2 moves from the low to high position at the same time. However, the weft thread 15 is not inserted into the weft needle fork, but grinds along the back of the weft needle which is moving out of the shed. In the FIGS. 15i and j, there is shown thatas soon as the weft needle fork crosses the line segment A2-C, the weft thread 15 jumps into the weft needle fork 19 and is inserted into the shed during the next cycle. The tension situation will now be explained with reference to FIG. 15k (change from thread 14 to thread 17). Thereby, it is crucial that, on the one hand, the minimum tension does not fall below a specific value (not below 0.2 N in the present example) because otherwise a weaving fault would result and, on the other hand, may not rise above a specific value (not over 0.5 N) because otherwise the thread tension would simply be too high and a tear-off would result. In FIG. 15l, the weft thread 14 is inserted from the thread guide A1, the weft needle pivot angle is ; the weft thread tension is in the acceptable (healthy) range. In FIG. 15m, there is shown a situation which can and should be avoided by the invention. The weft thread 17 from the thread guide A4 is inserted, and the weft needle pivot angle would be without the measures of the invention. The weft thread tension is too fluctuating and, furthermore, the weft thread tension at the reed beat-up is larger than intended. By virtue of the measures of the invention according to FIG. 15nwhen the weft thread 17 from the thread guide A4 is insertedthe weft needle pivot angle is reduced to . As a result, the weft thread tension is back in the acceptable (healthy) range.
[0035] The further application example for the present invention is explained in the FIG. 16a. In FIG. 16a the weaving point is shown in a wide ribbon, while in FIG. 16b the weaving of a narrow ribbon is shown. In this casejust for the sake of a simplified representationthe ribbon is reduced only on one sidethe left side. However, this has no influence on the principal problems and on the solution of these problems by means of the present invention. FIG. 16c shows the starting situation (FIG. 16a) of the wide ribbon with respect to the thread tension. The weft needle pivot angle is and the weft thread tension is in the acceptable (healthy) range. Without the measures of the invention, the situation according to FIG. 16d would occur upon transition to the narrower band. The ribbon is narrow when the weft needle pivot angle remains , then the weft thread tension is considerably smaller at the reed beat-up. By means of the measures of the invention, the situation according to FIG. 16e can now be achieved. The ribbon is narrow, the weft needle pivot angle is increased to . Thus, the weft thread tension at the reed beat-up has again the same amount as in the wide ribbon.
[0036] In principle, a continuous safe operation could be guaranteed with a stepper motor in the actuator 30 or 30a, but with a servo motor it seems reasonable to ensure that the control and thus the motion of the weft thread insertion needle remain in the desired phase. This can be ensured with a controlas shown in FIG. 17although such control can also be reasonable with a stepper motor so that the step does not get out of tact. For this purpose, a rotational angle measurement by means of a sensor (rotation angle measuring device 110) is required, the measured value of which can then be used for the feedback in the control loop 100. As can be seen from FIG. 17, for this purpose a corresponding control device 32 is provided. As a result, the target motion profile of the weft thread insertion needletaken e.g. from the main shaftis compared with the actual motion profile and readjusted. A simple first order controllerin this case a digital onecan be used.
[0037] Of course, the possibilities to optimize the ribbon needle weaving loom by means of control do not end here. For example, it is possible to optimize the weaving speed by selecting, for example, the delay (FIGS. 14a and 14b) in such manner that no warp thread is currently in the wrong position at the beginning of the insertion.
LIST OF REFERENCE NUMERALS
[0038] 4 warp threads
[0039] 8 shed
[0040] 9 woven material
[0041] 10 weft thread insertion needles
[0042] 10a thread receiving at the weft thread insertion needle
[0043] 10b last weft thread loop
[0044] 11 axis of the weft thread insertion needle
[0045] 14 weft thread and 1st weft thread, respectively
[0046] 14a thread guiding eye
[0047] 15 2nd weft thread
[0048] 16 3rd weft thread
[0049] 17 4th weft thread
[0050] 18 weft thread transport
[0051] 18a weft thread eye
[0052] 18b weft thread tension spring
[0053] 19 weft needle fork
[0054] 20 reed
[0055] 30 rotary actuator
[0056] 30a linear actuator
[0057] 32 control device
[0058] 34 band or pulley drive
[0059] 36 crank drive
[0060] 38 pushrod
[0061] 40 band with variable width
[0062] 50 restoring spring arrangement
[0063] 52 restoring spring
[0064] 54 restoring spring
[0065] 100 control loop
[0066] 110 rotation angle measuring device
[0067] A1 weft thread guide 1st weft thread
[0068] A2 weft thread guide 2nd weft thread
[0069] A3 weft thread guide 3rd weft thread
[0070] A4 weft thread guide 4th weft thread
