WO2006029733A1

WO2006029733A1 - Device for forming a shed with deformed spring

Info

Publication number: WO2006029733A1
Application number: PCT/EP2005/009486
Authority: WO
Inventors: Heinrich Planck
Original assignee: Ditf Deutsche Institute Für Textil- Und Faserforschung
Priority date: 2004-09-16
Filing date: 2005-09-03
Publication date: 2006-03-23
Also published as: EP1844187A1; DE102004044783A1

Abstract

The invention aims at reducing the harmful effects of the shock wave, induced by the shaft, on the life span of return spring in Jacquard knitting machines. Therefor, a spring is used which, in relaxed state, does not extend in a straight line in the fixing point zone. Thus, said spring is, in that respect, adjacent to several points of a rod inside the spring, so as to produce a friction damping. Another embodiment uses the dispersion of frequencies to reduce the amplitude of the shock wave.

Description

Shedding device with deformed spring

In jacquard weaving machines, in particular, the threads are inevitably moved in one direction, while they are pulled in the other direction by a spring. In general, the strand is moved by the spring to form the lower compartment. The spring is stationary or anchored to the ground at the other end in the weaving machine and keeps the harness cord and the heddle under tension in any operating condition.

Like any spring-elastic system, the arrangement of spring, heald and harness cord shows resonance phenomena including the propagation of waves passing through the linear system. The natural resonances of the system play no role as long as the speed of movement of the Webiitze is small compared to the resonance frequency. But at the moment, where the speed of movement ^"of the heald in the region of the resonance frequency passes, unpleasant waves occur in the spring. The waves are excited in the spring by the movement of the heald and run in the direction of the fixed end, where they are reflected and in the direction of the In unfavorable circumstances, it may even happen that the healdle becomes stress-free, because in the connection between the spring and the heald the revolving shaft has a phase position which is directed counter to the movement initiated by the movement of the harness cord.

The resonances within the spring also provide for increased mechanical stress and premature breakage. This is typical break points.

In order to dampen the resonances in the spring, it is known from EP 0 678 603 to provide the lower spring attachment point with a damping device. The unte¬ re spring attachment point consists of a Kunststoffform¬ part on which a threaded pin is formed. On the threaded pin, the coil spring is screwed. The threaded pin carries at its free end two resiliently movable legs which project into the interior of the spring and press against the spring. The two legs are in turn connected to one another at the end remote from the threaded pin and merge into two further legs which form an open fork.

It has been found that this type of spring damping is not unproblematic. If the contact force with which the legs act against the inside of the spring windings is too hard, no usable damping effect occurs. Effect on. On the contrary, the incoming waves are largely unthinkingly reflected at positions where the legs touch the inside of the spring. If, on the other hand, the contact pressure is too low, there is also no sufficient damping.

This unfavorable phenomenon is exacerbated because the spring elasticity of the plastic shows fatigue and is also temperature dependent.

Finally, threading the open legs into the spring is not easy.

An improvement brings the solution insofar as it is described in DE 101 24 022. In this arrangement, the tension spring is fixed at one end to a thread which is screwed between the turns of the tension spring. In extension of the thread, a rod extends into the spring. This rod has a non-linear course, for example a coiled or a wave-shaped course. The diameter of the rod is smaller at any point than the inside diameter of the tension spring. On the other hand, the bulges in the form of the waves or helix of the rod are chosen so that the tension spring is thereby imposed a non-linear course. As a result, the spring is more or less strongly against the rod with its windings. Incoming longitudinal waves in the spring lead to Reib¬ movements between the spring coils and the rod and consequently to a damping, since the kinetic energy is converted there into heat.

Due to the wave formation of the rod, a very fine tuning of Andruckkraftwindungen to the rod is possible. This prevents that the first contact point between the spring coil and the spring already acts as a total reflection point, whereby the problem described at the beginning would be shifted from the attachment point to the first contact point.

In the known solution, a plastic rod is used for anchoring, which leads to limitations in long-term stability and long-term behavior. Under the action of the coil spring, the original deformation of the rod gradually changes, and hence the damping also changes. This is of importance because the new form of spring damping allows a much longer service life of the spring to be achieved, so that the above-described effects can definitely play a role.

In addition, the production of the coiled rod is not easy.

Proceeding from this, it is an object of the invention to provide a shedding device, in which the problems geschil¬ above not occur.

This object is achieved with a Fachbild¬ device with the features of claim 1 or 22 ge solved.

In the new compartmentalizing device for a weaving machine, in particular a jacquard machine, a whirlwind, through whose loop the warp thread passes, is positively driven on one end, while at the other end a return spring is in effect. The return spring is a Coil spring. So that no standing resonance waves arise on the return spring, the return spring is provided with a damping device. In the present case, this consists of a substantially straight core element which projects into the interior of the helical return spring. In order to achieve the damping, the return spring, at least in a part of the region of the core element is provided with a non-straight course. As a result, it is sufficient that spring coils which are spaced apart from one another, ie not adjacent, rest on the core element. A vorbe¬ running wave leads to a movement of the spring coil and accordingly to a damping by friction.

The contact force of the spring is chosen so that the point of contact does not itself act as a reflection point for the entirety of the longitudinal vibration of the coil spring, on which the entire wave is reflected. When only part of the wave is reflected, ultimately a breakdown of the total impact into several portions is achieved, which also leads to the desired result.

In order to obtain the desired installation, the center axis of the helical spring can have a helical course, a single or multiple kinked course or one or more lateral offsets.

The core element, which projects into the spring, has a constant cross-section over its length.

The distance between the points of contact can be between 2 and 20 mm.

The material for the core element may be a thermoplastic or metal or ceramic.

In order to simplify assembly, the core element is integrally connected to the anchoring device or the connecting device.

Incidentally, developments of the invention are subject matter of subordinate claims.

Another way to avoid the detrimental effects of reflections on the return spring is to provide for frequency dispersion. The impact-like movement of the strand can be understood as a direct joint between the strand and the return spring, which runs along the shaft and is reflected in an unchanged form at the clamping point of the return spring. It is therefore provided according to another Aus¬ management example to change the duration of waves with different frequency along the shaft or to change the wavelength. In this way, a frequency dispersion of the Diracimpulses is taken da¬ with the impact energy is distributed along the return spring. The specific energy density per spring element is thus smaller and consequently a destructive effect due to an energy concentration, which leads to a beat of spring coils, avoided.

Another advantage of this embodiment is that no wear-prone damping element is required at the spring end. Nevertheless, the possibility of dispersion and damping at the spring end is possible and, under given circumstances, also advantageous. There are many possibilities for the required deformations and changes in shape. Thus, the spring may have straight sections which are offset from each other. That is, the central axis of the spring jumps, similar to a rectangular function, back and forth. Another possibility is to vary the diameter of the spring coils along the spring. However, care should be taken that expediently these Gestaltsänder¬ ments along the spring are not evenly distributed, in order to achieve no preference of certain frequencies.

The connection of the coil spring with the lower or the upper anchoring member can be done according to the prior art.

Furthermore, those combinations of features of the subclaims are claimed which are not reproduced by a concrete embodiment.

For the rest, further developments are the subject of subclaims. In the drawing, an embodiment of the article is shown in the invention. Show it:

1 is a schematic representation of a Fachbildeein¬ direction according to the invention,

2 shows an embodiment of the return spring with a bent course, in a sectional side view,

3, the return spring of FIG. 2 mounted on the anchoring device, with cut-back spring, 4 shows the upper connection between the Litzenschaft and the return spring,

Fig. 5 shows another embodiment of the return spring with offset course, in a sectional side view, and

6 shows a further embodiment according to the invention for reducing the impact effect.

FIG. 1 shows in a highly schematized manner the functional parts of the apparatus which form an essential part of the understanding of the invention in a jacquard machine. To the fach¬ forming device includes a drive device 1, of which a pulley 2 is illustrated. From the roller conveyor 2, a stringing cord fastened to a thickening bottom 3 leaves, which merges into a harness cord 4, which leads out between a glass grid or a guide floor 5. The Harnischkordel 4 continues to a chorus board 6 and exits through a hole 7 down. At the lower end, i. At the end of the Harnisch¬ cord 4, which rests from the pulley 2, a Weblit¬ ze 8 is attached. The heald 8 has an eyelet or an eye 9 for a warp thread 11. From the eyelet 9 go out obe¬ rer and a lower heddle shaft 12, 13, which lie on a common line. The lower end of the lower heddle shaft is connected to a return spring 14, which is anchored at 15 to the machine frame or to the floor.

The movement of the pulley 2 is transmitted via the Harnisch¬ cord 4 on the heald 8. As a result, the Harnischkordel 4 is pulled up and the eye 9 from the In this case, the return spring 14 is tensioned more strongly than in the neutral position of the heald 8, which corresponds to the closed shed.When the harness cord 4 is lowered, the return spring 14 pulls in the weaving cord 8 moves downwards to the same extent as the harness cord 4 moves downwards, so that the relevant warp thread 11 forms the bottom pocket.

As can be easily seen, the upward movement of the heald 8 is an inevitable movement, which is forced rigidly over the lengthwise ineligible harness cord 4. The opposite direction, on the other hand, is a movement initiated by the return spring 14 and, to a limited extent, only necessarily or rigidly.

The structure comprising harness cord 4, heddle 8, warp thread 11 and return spring 14 represents a spring-mass system which has one or more resonance frequencies. At high machine speeds, the frequency with which the heddle 8 is brought from the neutral position with closed shed into the position for the upper shed or in the position for the lower shed, at about 10 Hz. These frequencies, the are forced auf¬ the drive system 1, are in the order of the Resonanz¬ frequencies of the overall system, or the resonant frequency of subsystems. In addition, harmonics occur and waves can form on the linear structure between the chorus board 6 and the anchoring point 15 in the return spring 14 at these frequencies, which are reflected without appropriate countermeasures at the anchoring point 15 and standing waves in the return spring 14 who ¬ the. As a result, the return spring 14 at certain Places extremely heavy loads and tends to break.

In order to dampen the resonances, a return spring 14 illustrated in FIG. 2 can be used.

The return spring 14 shown has a Webblit¬ ze 8 facing straight portion 16 which extends almost over the entire length of the return spring 14. In this area, the return spring 14 is homogeneous, i. the spring coils have the same diameter and the longitudinal axis is straight in the relaxed state. Subsequent to the section 16, the course of the return spring is kinked in sections, so that four to five separate sections are formed, which run at an angle to one another. That the longitudinal axis of the return spring 14 extends in the region of the sections 17 zig-zag.

The return spring 14 consists of a round wire, which is wound to the return spring 14. The individual Feder¬ convolutions are in the relaxed state with the exception of the kinks at the transitions between the sections 17 to each other. The cross section of the individual spring coils is circular.

The return spring according to FIG. 2 is anchored as shown in FIG. 3. For this purpose, an anchoring element 18 is used ver¬ which is formed substantially rod-shaped. The anchoring element 18 has at its lower end an eyelet 19 which is to be hooked into a corresponding rail which is fixedly mounted on the machine frame. From the eyelet 19 is a substantially cylindrical shaft 20, which is provided at its upper end with a collar 21. Concentric with the shaft 20 extends half of the collar 21, an externally threaded pin 22. The Außenge¬ wind tap has a length corresponding to about 10 spring coils ent. On this threaded pin 22, the ge in Fig. 2 showed retraction spring 14 is screwed.

Following the thread 22, the anchoring element 19 forms an elongated cylindrical pin 23 which is straight and whose outer diameter is smaller than the clear width of the return spring 14.

When the return spring 14 according to FIG. 2 is screwed onto the threaded pin 22, it lies with the inside of the kinks, to which the individual sections 17 merge, with the small radial force acting on the cylindrical pin 23. The contact force results from the hardness of the spring and the degree of bending angle between adjacent sections 17. The smaller the bending angle, the lower the contact force. Due to the kink, the return spring 14 is in each case with the inside of one or two spring coil at the kink, i. at the interface between the sections 17 on the cylindri¬'s pin 23 frictionally.

In the assembled state, the return spring is under tension, so that the spring coils both in the Ab¬ section 16 and in the sections 17 are spaced from each other. This extraction also has an influence on the bending angle between the sections 17. Therefore, care must be taken to ensure that a sufficient radial contact force is achieved in the case of the traction force that occurs during operation. The frictional engagement of the spring coils on the cylindrical pin 23 causes the spring movement to a relative movement between the pin 23 and the spring coils is. As a result of the relative movement, the windings rub against the journal and thus damp a shaft or shock propagating along the return spring 14, as is initiated by the heddle 8.

Finally, for the sake of completeness, FIG. 4 also shows the connection between the lower heddle shaft 13 and the return spring 14. As can be seen there, a plastic molded body 27 is formed on the free end of the heddle shaft 13, which with respect to its construction faces the opposite end of the shaft Anchoring element 16 ent speaks. The plastic molded body forms a collar 28 as well as a threaded pin 29 which extends coaxially to the heddle shaft 13. The threaded pin 29 carries an external thread, which may be cylindrical or conical and on which, as described above, the return spring 14 is screwed until its end abuts the collar 28 as shown.

As is apparent from the above explanation, the damping of the disturbing shock is accomplished by a friction between the lower parts of the return spring 14 on the cylindri¬'s pin 23. The exemplary embodiment shown, for this purpose, provides for a return spring 14, the longitudinal axis of which extends in a zigzag-shaped manner in this region. However, a solution is also conceivable, as indicated in FIG. 5. In this case, the axis is not kinked in the region of the sections 17, but is set parallel in each case. By corresponding lateral offset diesel¬ be plant can be achieved, as previously explained in connection with FIG. 2 and FIG. 3. Finally, FIG. 6 shows an embodiment in which the harmful effects of the shock introduced via the heald 13 at the upper end of the return spring 14 are eliminated, not by heat, as in the previous embodiment, but by dispersion, ie by dispersion becomes.

The shock can be understood as a direct impulse. A Dirac pulse is known to be a superimposition of theoretically infinite many frequencies. If these frequencies propagate with different transit times along the return spring, the dirac pulse is literally stretched out, with the amplitude decreasing at the considered location. In the longitudinal system of the return spring 14, a reduction in amplitude means a smaller movement of the considered spring coil in the longitudinal direction of the spring. If it is ensured that the amplitude at each point is smaller than the distance of the spring coil from the adjacent spring coil, it is possible to avoid striking spring coils and thus premature wear of the spring.

In order to obtain this frequency dispersion, the return spring 14 is designed such that it shows a strongly inhomogeneous course between the lower anchoring element 18 and the lower weaving shank shaft 13. This inhomogeneous course may, for example, as shown in FIG. 6, consist in that the spring is kinked in sections in a zig-zag, wherein it is ensured that the sections 17 resulting from the buckling have different lengths. Another possibility is when the laterally offset design of FIG. 6 in the area between the heddle shaft 13 and the anchoring element 18 to be used ^" .

The variety of ways to achieve the different maturities is so great that their presentation would inflate the scope of the description of the figures unnecessarily. For that reason, only one further possibility is mentioned, for which a graphic representation in the simplicity is not required. Another possibility to produce different transit times is that the return spring along the region of interest is equipped with spring coils of different diameters.

A combination of different shapes is also possible.

Finally, it is conceivable to combine the frequency dispersion with the damping at the spring end.

In order to reduce the disturbing effects of the shock wave introduced by the heald on the life of the retraction spring in Jacquard machines, a spring is used which has a non-straight course in the region of the clamping point in the relaxed state. This ensures that the spring rests in this piece at a plurality of points on a stationary pin, which projects into the Fe¬ around there to generate a friction damping.

Another embodiment is based on a frequency dispersion in order to reduce the amplitude of the shockwave.

Claims

claims:

A shedding device (1) for a weaving machine, in particular for a Jacquard weaving machine, with a drive device (2) for producing a longitudinal movement, with at least one heald (8) containing an eyelet (9) and from diametrically opposite sides Weblitzenschäfte (12,13) go out, one of which (12) is coupled to the drive means (2), with a connecting means (27) on the other We¬ flitzenschaft (13), with one of the at least one heald (8) associated Coil spring (14), one end of which is attached to the connecting device (27) and which serves to pull back the heddle (8), with an anchoring device (16) for stationary anchoring of the other end of the helical spring (FIG. 14), and with a straight damping element (22) which is at least at a plurality of spaced-apart locations with the coil spring (14) into contact, wherein the helical spring at least one deformation auf¬ we is, which means that the central axis of the ent spanned helical spring there is not straight to such an extent that it rests against the damping element in the mounted Zusatand.

2. shedding device according to claim 1, characterized in that the damping element (22) is a Kern¬ element (22) which is arranged in the coil spring (14) and which is linear.

3. shedding device according to claim 2, characterized in that the helical spring rests on the damping element with such a force that longitudinal vibrations in the helical spring can spread in a damped manner over the contact point.

4. shedding device according to claim 2, characterized in that the coil spring rests against the Dämpfungs¬ element with such a force that the Berüh¬ tion point does not act as such a reflection point for Longitudi- nalschwingungen in the helical spring on which the longitudinal vibrations substantially be completely reflected.

5. shedding device according to claim 2, characterized in that the damping element (22) is a cylin¬ drical or laterally flattened structure.

6. shedding device according to claim 2, characterized in that the central axis of the helical spring is shaped wave-shaped, that the waves lie in a common plane.

7. shedding device according to claim 2, characterized in that the central axis of the helical spring has a helical, a single or multiple kinked course or one or more lateral Ver¬ sets.

8. shedding device according to claim 2, characterized in that the core element (22) has a substantially constant over the length of the cross section.

9. shedding device according to claim 2, characterized characterized in that the distance between points of contact is between 2 and 20 mm.

10. shed forming device according to claim 2, characterized in that the material for the core element ther moplast as polyamide, polyethylene and polyurethane or other materials such as metal, ceramic, thermosets or a vulcanizable material.

11. shed forming device according to claim 1, characterized in that the core element (22) with the anchoring device (16) or the connecting device (27) is firmly connected.

12. Shedding device according to claim 1, characterized in that the drive device (1) is a shed forming device of a jacquard machine.

13. Shedding device according to claim 1, characterized in that the connecting device (27) is formed by a plastic molded part, which is material and / or positively connected to the respective end of the Weblitzenschaf¬ tes (13).

14. Shedding device according to claim 18, characterized in that the connecting device (27) has a thread (29).

15. shedding device according to claim 1, characterized in that the anchoring device (16) has a thread (21).

16. shedding device according to claims 18 or 19, characterized in that ^" the thread (21) is an external thread.

17. shedding device according to claim 15, characterized in that the thread (21) is a tapered thread.

18 shedding device according to claim 16, characterized in that the core diameter of the thread (21), starting from a diameter value which is smaller than the inside diameter of the coil spring (14), increases to a diameter Durch¬, which is equal to or greater than that Clear width of the coil spring (14).

19. shed forming device according to claim 1, characterized in that the helical spring (14) is a Schrau¬ benzugfeder, in which the ein¬ individual spring coils lie in the relaxed state close to each other.

20. shedding device according to claim 1, characterized in that the helical spring (14) made of metal, preferably steel.

21. Shedding device (1) for a loom, in particular for a Jacquard weaving machine, with a drive device (2) for generating a Longi- tudinalbewegung, with at least one heald (8) containing an eyelet (9) and from the diametrically opposite sides Weblitzenschäfte (12,13) go out, one of which (12) is coupled to the drive means (2), with a connecting means (27) on the other We¬ flitzenschaft (13), with one of the at least one heald (8) associated Coil spring (14), one end of which is attached to the connecting device (27) and which serves to pull back the heddle (8), with an anchoring device (16) for stationary anchoring of the other end of the helical spring (FIG. 14), and wherein the helical spring has a multiplicity of deformations / shape changes (), which results in waves having different frequencies propagating along the helical spring at different speeds / wavelengths.

22. shedding device according to claim 1, characterized in that the helical spring (14) made of metal, preferably steel.

23. shedding device according to claim 1, characterized in that the deformations / shape changes () in a change in diameter, a change in pitch, ei¬ nem axis offset or the like, or a combination of both exist.

24. shedding device according to claim 1, characterized in that the deformations / shape changes () along the coil spring (14) are distributed irregularly.