Shed-forming device, circular loom equipped therewith for leno fabrics and method of shed formation

Abstract

The shed forming device (10) for a circular loom (1) has warp belt lifting elements (20, 21) for guiding the warp belts (5, 6) to two warp belt groups (11, 12) and giving them alternating relative movements to form a shed (40). An adjusting element (24) engages one set of the warp belt lifting elements (20, 21) and gives the warp belt lifting elements (20, 21) a lateral reciprocating movement between a first end position where adjacent warp belts (5, 6) of the two warp belt groups (11, 12) do not intersect each other and a second end position where adjacent warp belts (5, 6) of the two warp belt groups (11, 12) always intersect each other longitudinally. The adjusting element (24) can be adjusted non-contactly via an actuator (35) and has adjusting magnets (24b, 24c) which can be repelled or attracted non-contactly via the actuator (35) through a magnetic interaction relationship. The damping stop elements (33, 34) define the positions of the first end and the second end.

Description

[Technical Field]

[0001] This invention relates to a shed forming apparatus for a circular loom. Furthermore, this invention relates to a circular loom and its use in producing leno fabrics. This invention also relates to a shed forming method. [Previous Technology]

[0002] Circular looms for producing fabrics, having a reed arranged coaxially with the main shaft of the circular loom, are well-known prior art. The main shaft forms the main axis of the circular loom. Warp guide elements, designed to supply multiple warp tapes to the circular loom, are arranged around the reed. A shed forming device gathers these supplied warp tapes into two warp tape groups and gives them an alternating relative motion, thereby opening and closing the shed between the two warp tape groups. The shuttle moves along a track path in the open shed, inserting the weft tape into the shed during the movement, thereby forming the fabric. In modern circular looms, several shuttles typically circulate simultaneously within their respective sheds in the reed. The fabric is pulled out through weaving loops. Such a circular loom is known, for example, in document CH 657163 A5.

[0003] Among the fabrics that can be produced on a circular loom, so-called leno fabric, also known as LENO fabric, is particularly important because in these fabrics, two adjacent warp tapes are not arranged parallel to each other, but rather one warp tape (so-called leno belt or leno thread) crosses to the other warp tape (called the base tape or base line). In this way, the weft tape is incorporated between the pair of warp tapes in an anti-slip manner. Therefore, leno fabric can contain weft tapes spaced apart from each other, so that air and water can flow through the leno fabric, which is important. For example, it is used for food packaging, such as vegetables or fruits, and allows empty or filled food packaging to be washed and reused. Leno fabric can have a mesh structure.

[0004] A fundamental problem concerning the production of leno fabrics on a circular loom is the design and guidance of these opposing warp guide elements (also known as partial shafts) so that, after each alternating movement forms a shed, two cooperating warp belts can be alternately arranged. This problem is solved by the circular loom described in EP 0267509 A2; wherein, for the alternating arrangement of the leno belts, the adjustment means, after each stroke forming a shed, engages at least one of a pair of partial shafts to produce an instantaneous lateral opposing reverse displacement of these partial shafts, which are freely guided by the warp guide device to form a shed from one of the partial shafts and to perform a side change on the other partial shaft. These partial shafts can carry comb-like guides for these warp strips, each of which has a tape eyelet at its free end to guide the warp strips to form a shed and to define warp strip guide slits between each other for freely guiding the warp strips for side changes. Thus, it is necessary for these partial shafts in a pair to carry the comb-like guides arranged opposite each other.

[0005] Based on the circular loom described in EP 0267509 A2, there have been several further developments in recent years for circular looms used to produce leno fabrics.

[0006] WO 2021 / 105847 A1 and CN 114787436 A disclose a circular loom for producing leno fabrics, similar to the circular loom in EP 0267509 A2. In WO 2021 / 105847 A1, to reduce friction between the warp threads and the eyelets, it is suggested that the eyelets on the comb-like guides of the warp threads be equipped with ceramic pins. In CH 657163 A5 mentioned above, it is also suggested that these eyelets be fitted with eyelet pins made of ceramic, sintered ceramic, steel, or similar materials. Ceramic eyelet pins are also proposed in CN 202644 031 U.

[0007] Document GB 2290088 A discloses an apparatus for manufacturing leno fabric using warp, weft, and reed. The annular forming mechanism shown in Figure 1 includes a plurality of spindles, two leno deflectors, and a plurality of hooks. These leno deflectors are driven by a piston rod through a transmission device to perform reciprocating motion. These leno deflectors have a plurality of strands, through which the warp is guided. The leno fabric is formed by the reciprocating motion of these leno deflectors. The movement of these piston rods can be achieved by means of an electromagnet through a non-contact transmission device. When energized, the electromagnet pushes the piston rod in a first direction; when de-energized, the piston rod is pushed back in the opposite direction by a spring, thus creating reciprocating motion. The piston rod (which is the actuating element) is not equipped with a magnet.

[0008] Circular looms used for producing leno fabrics have been shown to have limitations that prevent the increase of process speed from maximizing process reliability. Such limitations involve a sharp increase in wear and noise, as well as a decrease in the accuracy of warp belt position as the process speed increases. [Summary of the Invention]

[0009] The present object of the present invention is to further develop a shed forming device for a circular loom for the production of leno fabrics, and a circular loom equipped with such a shed forming device, so that high process speeds and high process reliability can be achieved in the production of leno fabrics. Furthermore, wear and noise of the shed forming device and the circular loom equipped with it are reduced.

[0010] The present invention achieves its proposed objective by providing a shed forming apparatus for a circular loom, wherein warp belt lifting elements are arranged in a first group and a second group for guiding warp belts into two warp belt groups, wherein the warp belt lifting elements of the first and second groups give the two warp belt groups an alternating relative movement to form a shed, wherein at least one adjusting element engages at least one of the warp belt lifting elements of these groups, the adjusting element giving the warp belt lifting elements a lateral reciprocating movement between a first end position where adjacent warp belts of the two warp belt groups do not intersect each other and a second end position where adjacent warp belts of the two warp belt groups always intersect each other longitudinally, the adjusting element can be adjusted non-contactly by an actuator, the adjusting element having at least one adjusting magnet, the at least one adjusting magnet repelling or attracting non-contactly by means of a magnetic interaction relationship through the actuator. The adjusting magnet may be designed as a permanent magnet.

[0011] The solution according to the invention provides the advantage that the parts will not wear out and the noise is significantly reduced, while at the same time, the operating speed can be increased by at least 30% compared with known circular looms.

[0012] Because at least one adjusting magnet repels or attracts non-contactly via an actuator through a magnetic interaction, these warp belt lifting elements remain in their end positions for a specific period of time after a lateral switch. The fact that these warp belt lifting elements are temporarily held in their end positions ensures that the warp belts are correctly inserted into their respective guides, for example, into the slits between the comb teeth, as will be described in detail below, because the warp belts can be more precisely positioned in their end positions, and reliably reach "their" guides by briefly stopping these warp belt lifting elements. If the mutual repulsion of the magnets is chosen as the magnetic interaction, this makes a particularly simple structure possible.

[0013] In another development of this embodiment, the actuator has at least one actuator magnet designed as a permanent magnet, and can initiate or de-initiate a magnetic interaction with at least one adjusting magnet. Essentially, a ferromagnetic element can be provided instead of the actuator magnet or adjusting magnet, thereby limiting the magnetic interaction to an attractive force. However, in reality, the combination of a permanent magnet and a ferromagnetic element has the disadvantage of insufficient attractive force, thus failing to achieve the desired high operating speed. According to the invention, it is conceivable that the actuator includes a switch lever (preferably designed as a pivot lever), on which at least one actuator magnet is arranged in a manner that allows it to initiate or de-initiate a magnetic interaction with at least one adjusting magnet by moving the switch lever.

[0014] In a robust embodiment of the shed forming device, which contains few individual parts and is subject to little wear, the switch lever is mounted in a pivot bearing and pre-tensioned to a defined position by a leg spring.

[0015] In another preferred embodiment of the shed forming apparatus according to the invention, the adjusting element has two adjusting magnets spaced apart from each other and can alternately induce a magnetic interaction with the actuator, thereby adjusting the adjusting element to repeatedly move the belt lifting elements assigned to it between a first end position and a second end position.

[0016] In an alternative preferred embodiment of the shed forming apparatus according to the invention, the actuator includes at least one actuator magnet designed as an electromagnet, the adjusting magnet attracting or repelling through the actuator magnet by applying current to the actuator magnet, the actuator preferably having a switching lever for applying current to the actuator magnet.

[0017] In another alternative embodiment of the shed forming apparatus according to the invention, the actuator includes at least one actuator magnet designed as an electromagnet, the adjusting magnet attracting or repelling through the actuator magnet by applying current to the actuator magnet, the actuator preferably having a switching lever for reversing the direction of the current applied to the actuator magnet.

[0018] In a particularly convenient embodiment of the shed forming apparatus according to the invention, the shed forming apparatus includes stop elements defining the positions of a first end position and a second end position. In this case, preferably, if these stop elements are made of a damping material or have damping material provided on their surfaces, the damping material is, for example, a natural or artificial elastomer.

[0019] Such stop elements offer several advantages. First, they precisely define the end positions of the lateral reciprocating motion of these warp lifting elements, resulting in improved leno fabric. Second, the damping material suppresses the impact exerted on the stop elements by these warp lifting elements, thereby reducing both dynamic stress on the circular loom components and the generated noise. Third, the fact that these warp lifting elements spring back from these stop elements after they abut can be reduced or even completely prevented from stopping by these stop elements (especially those containing damping material). These warp lifting elements and the warp belts themselves can therefore be positioned at their end positions with less vibration or even no vibration. Therefore, improved movement sequence and higher operating speeds are possible.

[0020] If these warp belt lifting elements directly abut against these stop elements at the first and second end positions, the positions of these warp belt lifting elements will not deviate from these defined end positions; if there is only an indirect mechanical relationship between these warp belt lifting elements and these stop elements, deviation will occur. Instead, the final positioning of these warp belt lifting elements is always guaranteed at these end positions. Furthermore, the design of the shed forming device is thus simplified.

[0021] In mechanics, the term "stop" is defined as the expected endpoint of an object's path of motion. At this endpoint, the object "hits" another object—the physical obstacle itself is called the stop element.

[0022] Furthermore, it is useful if the first set of webbing lifting elements are formed through the teeth of the first comb, forming eyelets for guiding the webbing, and the second set of webbing lifting elements are formed through the teeth of the second comb, wherein the first or second comb is alternately reciprocating between a first end position and a second end position via adjusting elements. In this embodiment, preferably, the first comb is mounted on a comb holder for reciprocation, and the stop elements are arranged on the side of the comb holder facing the first comb. Such an embodiment is robust, structurally simple, and ensures precise positioning of the comb at the end position. Unintended pivoting of the comb is eliminated.

[0023] In a particularly preferred embodiment of the shed forming apparatus according to the invention, the first comb is mounted on the comb holder via a shaft so as to be pivotable about this shaft. The stop elements and the shaft form an isosceles triangle. In each case, the distance between the shaft and one of the stop elements forms the isosceles side of the isosceles triangle, and the distance between the stop elements forms the base of the isosceles triangle, the length of which is greater than the length of the base. This embodiment provides the advantages of a robust and simple structure and precise positioning of the comb at its ends. Furthermore, it has the advantage of reducing braking torque through the relatively large distance between the shaft and the stop elements, thereby reducing the mechanical load on the parts.

[0024] Furthermore, the present invention achieves the stated objective through a circular loom comprising: a reed; a plurality of warp guide elements arranged around the reed for supplying a plurality of warp tapes to the circular loom; a plurality of shuttles circulating within the reed for inserting weft tapes into sheds formed by the warp tapes; and a main drive for driving the shuttles; and wherein the circular loom includes a shed forming device according to the present invention arranged around the reed, as described above.

[0025] In order to achieve particularly precise control of the circular loom when producing leno fabric, while still achieving a simple structure, the circular loom includes a control cam frame driven by the main drive unit, a lifting control cam formed on the control cam frame and used to control the first and second groups of warp belt lifting elements, and an actuator control cam formed on the control cam frame and used to control the actuator; preferably, the lifting control cam and the actuator control cam are integrally formed on the control cam frame.

[0026] Furthermore, preferably, the circular reed has a plurality of reed strips and spacers, some of the reed strips being arranged alternately with at least one spacer strip, and adjacent reed strips, adjacent reed strips and spacers being arranged at equal distances from each other in the circular reed and having the same width. Embodiments of this circular loom provide maximum freedom and flexibility when the circular loom is equipped with these warp strips.

[0027] According to the method of forming a shed on a circular loom of the present invention, a plurality of warp strips are provided to two warp strip groups, and the two warp strip groups are given an alternating motion relative to each other to form a shed. At least one set of lateral reciprocating motions of the two warp strip groups is given between a first end position where adjacent warp strips of the two warp strip groups do not intersect each other and a second end position where adjacent warp strips of the two warp strip groups always intersect each other in the longitudinal direction. The lateral reciprocating motions of at least one set of the two warp strip groups are performed in a non-contact manner by means of an adjusting element having at least one adjusting magnet. At least one adjusting magnet repels or attracts non-contactly through an actuator via a magnetic interaction relationship.

Implementation Method

[0030] Figures 1 and 2 show an embodiment of a circular loom 1 according to the present invention. The circular loom 1 includes a frame 2, for example, a polygonal frame 2, preferably formed by a plurality of shaped tubes welded or screwed together, and constituting a container for the parts of the circular loom 1. In the middle of the frame 2, reeds 4 are arranged on a frame 32. The reed 4 includes upper rings 4c and lower rings 4d, in which a plurality of reeds 4a and spacers 4b are arranged in a uniformly distributed manner. These spacers 4b keep the upper rings 4c and lower rings 4d parallel to each other and spaced apart. Together with the spacers 4b, the upper rings 4c and lower rings 4d support the reeds 4a in position. The upper rings 4c and lower rings 4d constitute guides for the shuttle 9 to circulate in the reed 4. Concentrically with the reed 4, a weaving loop 14 is centrally arranged within the reed 4, through which the finished tubular fabric 3 is pulled out. Outside the reed 4, feeders 7 for the warp strips 5, 6 are arranged so as to be distributed around the reed. Furthermore, warp guide elements 8, for example in the form of length adjustment compensators, are arranged around the reed 4. A large number of warp strips 5, 6 are supplied to the circular loom 1 in a peripherally distributed manner via or through these warp guide elements 8. These warp strips 5, 6 travel from these warp guide elements 8 to the shed forming devices 10, which are described in detail below. In this example, several shed forming devices 10, each representing a shed forming section, are arranged around the reed 4. From the shed forming devices 10, these warp strips 5, 6 pass through the slits between the reed bars 4a and / or the spacers 4b of the reed 4 in the direction towards the weaving loop 14. When the leno fabric 60 is produced (see Figure 8), the two warp strips 5, 6 always pass through the slits between the two reeds 4a, or between the reeds 4a and the spacers 4b. For maximum freedom and flexibility in equipping the circular loom 1 with the warp strips 5, 6, it is advantageous if the reeds 4a and the spacers 4b are of the same width and distance from each other, so that all the slits formed between the reeds 4a, or separately, between the reeds 4a and the spacers 4b, have the same width. The spacers 4b are typically slightly longer than the reeds 4a to engage with and be secured in the grooves of the upper ring 4c and the lower ring 4d. This difference in length serves a purpose after the circular reed 4 is assembled—the ends of the spacers 4b are first screwed onto the reed rings 4c, 4d—resulting in the reed rings 4c, 4d resting snugly against the spacers 4b, thus stabilizing the reed structure. These reeds 4a are inserted (glued) into the spaces between these spacers 4b—the assembly comb (=spacer comb) helps to set equal distances between these reeds 4a—in this way, they exhibit a slight difference in length at their lower and upper ends compared to the spacers 4b. For example, these reeds 4a can be installed in a "group of three," that is, three reeds 4a are connected to each other, for example, welded together.This is cheaper than, for example, making several reeds 4a from a single piece.

[0031] However, as an alternative, these spacers 4b can be designed to have the same length as these reeds 4a.

[0032] At the shed forming device 10, the warp tapes 5 and 6 are divided into two warp tape groups 11 and 12, which are given relative alternating motion (up and down motion in this example) by the relative movement of the warp tape lifting elements 20 and 21. By this, the shed 40 (also called the traveling shed) is opened and closed (also called the shed change). Please refer to Figures 3a to 3c. In the shed 40, the shuttle 9 moves along the track path along the reed 4 (inside), thereby pulling the weft tape 61 off the weft tape spool 62 it carries and inserting it into the shed 40, see Figure 2. Through the change of the shed, that is, by giving the reverse-rotating warp tape groups 11 and 12 a reverse motion, the last inserted weft tape 61 is sandwiched between the warp tape groups 11 and 12, and is thus incorporated into and fixed in the fabric 3 in an anti-slip manner. Typically, several shuttles 9 operate at equal distances from each other in the reed 4, each shuttle 9 moving in its own shed 40. The produced tubular fabric 3 is guided from the weaving ring 14 to the take-off rollers 13 and through them to be turned away from the circular loom 1, see Figure 1. A ring cable conduit 15 is used to actuate all electrical and electronic components of the circular loom 1. Control of the circular loom 1 is achieved through a control panel 16, which also includes operator operating devices, see Figure 2. A control cam frame 17 is used to actuate the shed forming device 10 and is driven by the main drive 18 of the circular loom 1, causing the control cam frame 17 to rotate about the central axis 19 of the circular loom 1. In the illustrated embodiment of the circular loom 1, the control cam frame 17 is formed through a ring 17a, which is connected to a hub 17c via spokes 17b, the hub 17c being located on the central axis 19. A web is formed on the underside of the ring 17a, which forms the control cams. Alternatively, the control cam holder 17 may be a centrally arranged disk containing the web forming the control cams.

[0033] Referring to Figures 3a, 3b, and 3c and in conjunction with Figure 4a, Figure 4a schematically shows a side view of the shed forming device 10 of the circular loom 1 in Figure 1. The shed forming device 10 includes warp lifting elements 20 arranged in a first group for guiding warp strips 5 in a first warp strip group 11, and warp lifting elements 21 arranged in a second group for guiding warp strips 6 in a second warp strip group 12. When viewed relative to the central axis 9 of the circular loom 1, the warp lifting elements 20 of the first group represent the inner warp lifting elements 20; while when viewed relative to the central axis 9 of the circular loom 1, the warp lifting elements 21 of the second group represent the outer warp lifting elements 21. The warp lifting elements 20, 21 of the first and second groups give the two warp strip groups 11, 12 an alternating relative movement to form the shed 40.

[0034] The shed forming apparatus 10 is designed to produce leno fabric 60, with intersecting warp tapes 5 as leno threads, warp tapes 6 as the baseline, and weft tapes 61 incorporated into both in an anti-slip manner (see Figure 8). Adjusting elements 24 engage at least one of the warp tape lifting elements 20, 21 of these groups—in this exemplary embodiment, these warp tape lifting elements 20 are arranged in the first group—these adjusting elements give these warp tape lifting elements 20 lateral reciprocating motion between a first end position where adjacent warp tapes 5, 6 of the two warp tape groups 11, 12 do not intersect each other and a second end position where adjacent warp tapes 5, 6 of the two warp tape groups 11, 12 always intersect each other longitudinally.

[0035] The first group of warp belt lifting elements 20 are formed by the teeth 22a of the first comb 22, wherein eyelets 22b for guiding the warp belt 5 are formed in these teeth 22a. Belt guide slits for freely guiding the lateral changes of the warp belt 6 are formed between these teeth 22a. The second group of warp belt lifting elements 21 are formed by the teeth 23a of the second comb 23, wherein eyelets 23b for guiding the warp belt 6 are formed in these teeth 23a. Belt guide slits for freely guiding the lateral changes of the warp belt 5 are formed between these teeth 23a. The first comb 22 and the second comb 23 are oriented in opposite directions, i.e., the free ends of the teeth 22a of the first comb 22 point downwards, while the free ends of the teeth 23a of the second comb 23 point upwards. The first comb 22 is alternately and repeatedly moved between a first end position and a second end position by means of the adjusting element 24. In the exemplary embodiment shown, this is implemented by mounting the first comb 22 on the comb holder 22c via the shaft 22d, and pivoting it between a first end position and a second end position via the eccentric bolt 24a of the adjusting element 24, see Figures 3a and 4b. In an alternative embodiment, not shown in the figures, the first comb 22 may be mounted in a guide rail on the comb holder 22c and may be displaced using an eccentric wheel, slider, or gear. The warp 6, guided by the second set of warp lifting elements 21 or separately via the second comb 23, and given only up-and-down movement, is referred to as the "baseline" or "base strip". The warp 5, guided by the first set of warp lifting elements 20 or separately via the first comb 22, and given both up-and-down and reciprocating movement, is referred to as the "yarn thread" or "yarn belt".

[0036] The shed forming apparatus 10 includes an upper deflecting roller 25 and a lower deflecting roller 26. See, for example, FIG4a. A belt 27 is guided around the upper deflecting roller 25 and the lower deflecting roller 26, and a first set of belt lifting elements 20 (comb holder 22c in this example) and a second set of belt lifting elements 21 (second comb 23 in this example) are mounted on the belt 27. The first comb 22 and the second comb 23 are arranged opposite to each other and are connected to the belt 27 in an endless configuration. The control cam holder 17 has a lifting control cam 17d (see FIG5a) designed as an eccentric web. The lifting control cam 17d has a control roller 28 for a lifting control lever 29, which is pivotally mounted on a bearing seat 30. The lifting control lever 29 deflects upon engagement with the lifting control cam 17d. The lifting control lever 29 is connected to one of these belts 27 (or alternatively to the comb frame 22c), whereby its deflection raises or lowers the belt 27, thereby producing a lifting motion. The bearing housing 30 rests on the base plate 31.

[0037] Figure 3a shows the warp lifting elements 20 of the shed 40 in the open position, allowing the shuttle to move within the shed 40 and the warp tapes to be inserted into the fabric 3. The warp tapes 5 of the warp tape group 11 restrict the space of the shed 40 towards the top. The warp tapes 6 of the warp tape group 12 restrict the space of the shed 40 towards the bottom. The warp tapes 5, 6 are parallel to each other, and in the schematic diagram of Figure 3a, the warp tape 5 is guided to the left of the warp tape 6. The first comb 22 thus pivots to its first end position (the end position on the left in the figure). The pivoting of the first comb 22 occurs after the weft tape has been inserted. Figure 3b shows the positions of the first and second warp lifting elements 20, 21, in which the warp tapes 5 are located below the warp tapes 6. In this position, the crossing of adjacent warp tapes 5, 6 can occur. The first comb 22 has thus been pivoted to its second end position (the end position on the right in the figure). Figure 3c shows the open shed 40 after the change of stroke has occurred, similar to Figure 3a, except that adjacent warp strips 5 and 6 cross in the longitudinal direction. This is evident from the fact that, in the figure shown, warp strip 5 is guided to the right of warp strip 6. The first comb 22 is in the second end position. During the next stroke, the first comb 22 can then be pivoted back to its first end position, which again causes the lateral changes of these warp strips 5 and 6.

[0038] Furthermore, Figures 3a and 3c show stop elements 33 defining the first end position of the first comb 22 and stop elements 34 defining the second end position of the first comb 22, thereby precisely defining the positions of the warp tapes 5 relative to the warp tapes 6. These stop elements 33 and 34 directly abut against the comb at their respective end positions, ensuring no tolerance occurs when the first comb 22 is positioned at its end, resulting in an improved leno fabric 60. Because the first comb 22 is reciprocated while mounted on the comb holder 22c, and these stop elements 33 and 34 are arranged on the side of the comb holder 22c facing the first comb 22, tolerances become irrelevant due to the direct contact between the first unit 22 and the stop elements 33 and 34, thus creating a particularly simple yet precise structure. As can be seen from Figures 3a and 3c, the first comb 22 is mounted on the comb holder 22c via a shaft 22d so that it can pivot about the shaft 22d. These stop elements 33, 34 and the shaft 22d form an isosceles triangle. The distance between the shaft 22d and the stop element 33, and the distance between the shaft 22d and the stop element 34, each form the isosceles side 'a' of the isosceles triangle. The distance between these stop elements 33, 34 forms the base 'b' of the isosceles triangle. As shown in Figures 3a to 3c, it is evident that the length of the isosceles side 'a' of the isosceles triangle is greater than the length of the base 'b'. Due to the large distance between the shaft 22d and these stop elements 33, 34, the braking torque of the first comb 22 on the stop elements 33, 34 is significantly reduced. These stop elements 33, 34 contain damping materials 33a, 34a, such as natural or artificial elastomers. This suppresses the impact of the first comb 22 on these stop elements 33, 34, thereby reducing the dynamic stress on the components of the circular loom 1 and the generated noise. Damping is based on absorbing impact forces through the damping materials 33a, 34a, or respectively based on the effect of shock absorbers. When these stop elements 33 and 34 are impacted, the damping material also prevents the first comb 22 from bouncing unnecessarily.

[0039] As can be seen in Figures 4a and 4b, the adjusting element 24 is pivotally mounted on the comb holder 22c and includes an eccentric bolt 24a through which the first comb 22 pivots. The eccentric bolt 24a enables or separately initiates the actual pivoting of the first comb 22 by movement about its axis. The path traveled by the first comb 22 in its movement is thus predetermined by the eccentricity of the bolt 24a. The adjusting element 24 has at least one adjusting magnet 24b, 24c (optionally designed as a permanent magnet), which, through magnetic interaction, repels or attracts the adjusting element 24 in a non-contact manner via the actuator 35, thereby pivoting the adjusting element 24. For this purpose, the actuator 35 in the embodiment shown in Figure 4a has at least one actuator magnet 35a, 35b designed as a permanent magnet and capable of inducing or disintegrating a magnetic interaction with the at least one adjusting magnet 24b, 24c. It is important that the pivoting of the adjusting element occurs in a non-contact manner. This means that the actuator magnets 35a and 35b are always spaced from the adjusting element 24 during operation. As a result, mechanical stress and noise are reduced. The actuator 35 has a switching lever 36 (preferably designed as a pivot lever), which is pivotally mounted in a pivot bearing 37 and pre-tensioned to a defined position by a leg spring 38. The control roller 39 engages the switching lever 36, and under the pre-tension of the leg spring 38, the control roller 39 abuts against the actuator control cam 17e formed on the periphery of the control cam holder 17 to follow the actuator control cam 17e, thereby adjusting the switching lever 36 of the actuator 35. The actuator control cam 17e and the lifting control cam 17d are integrally formed on the control cam holder 17. As a result, there is no offset between the two control cams 17d and 17e, which increases the accuracy of control, see Figures 5a and 5b.

[0040] Figure 4b shows a top view of the shed forming apparatus 10 in Figure 4a. The switch lever 36 of the actuator 35 is designed as a pivot lever and has two actuator magnets 35b, 35c spaced apart from each other. Depending on the position of the switch lever 36, these actuator magnets 35b, 35c enter into a magnetic interaction relationship with one of the adjusting magnets 24b, 24c of the adjusting element 24. In the embodiment shown in Figure 4b, the actuator magnet 35a is currently in an interaction relationship with the adjusting magnet 24b. The specific shapes of the switch lever 36 and the adjusting element 24 can be set to the desired shapes according to actual needs, such as crescent, semi-circular, circular, rectangular and similar shapes. In this case, it is important that they satisfy these functions according to the invention and provide certain exemptions so that the interaction of the movement of the switch lever 36 and the adjusting element 24 can be guaranteed under all operating conditions. For example, the adjusting element can be simply designed in the shape of a rod, as shown in the variation in Figure 5a. Based on the polarity of these adjusting magnets 24b, 24c and these actuator magnets 35a, 35b, the adjusting magnets 24b, 24c and the actuator magnets 35a, 35b are either mutually repelling or mutually attracting in their magnetic interaction, and thus the adjusting element 24 is adjusted, which alternately deflects the first comb 22 from a first end position to a second end position via the eccentric bolt 24a, or vice versa. In a simple embodiment, magnets 24b, 35a and 24c, 35b are respectively designed to repel each other in their magnetic interaction. Alternatively, if magnets 24b, 35a and 24c, 35b are respectively polarized to attract each other in their magnetic interaction, then stop elements 33, 34 as described above should be provided to limit the respective end positions of the first comb 22 or their respective deflections, as previously described, and to suppress its impact. This is particularly important because the magnetic attraction becomes stronger, and the magnets 24b, 35a and 24c, 35b, which are respectively polarized to attract each other, move closer to each other, thereby accelerating the movement of the first comb 22, which moves closer to one of its end positions. In this embodiment, the stop elements 33, 34 can therefore be implemented in a particularly effective yet structurally simple manner in terms of the magnetic attraction interaction relationship via the actuator 35, ensuring the non-contact adjustability of the adjusting element 24. In the top view of FIG4b, the adjusting magnets 24b, 24c are not visible because they are arranged on the bottom side of the adjusting element 24. They are therefore symbolically marked with arrows in the figure. The switch lever 36 is pre-tensioned to the actuator control cam 17 in the pivot bearing 37 via a leg spring 38 resting on the stop 38a, also see FIG4c.

[0041] FIG. 4c shows a top view of a modified shed forming apparatus 10 of FIG. 4a. This modification differs from the embodiment of FIG. 4b in that the switch lever 36 has only one actuator magnet 35a, which is engaged in a repulsive or attractive magnetic interaction with one of the adjusting magnets 24b, 24c at different positions. In this embodiment, the switch lever 36 has a longer pivoting path during operation than in the embodiment of FIG. 4b, so that the actuator magnet 35a alternately induces a magnetic connection with one of the two adjusting magnets 24b, 24c. The magnetic connection is provided when the actuator magnet 35a is positioned substantially relative to one of the two adjusting magnets 24b, 24c. All other functions and elements of this modified shed forming apparatus correspond to the embodiment of FIG. 4b, and therefore refer to the above description.

[0042] Figure 5a shows a perspective view of the shed forming apparatus 10 shown in Figures 4a and 4b, viewed from the inside out. Figure 5b shows a perspective view of the shed forming apparatus 10 shown in Figures 4a and 4b, viewed from the outside in. The function and interaction of the parts described with reference to Figures 4a and 4b can be seen particularly clearly from these two views.

[0043] Figures 6a and 6b show an alternative embodiment of the shed forming apparatus 10, wherein the actuator 35 has an actuator magnet 50 designed as an electromagnet and includes an electromagnet coil 51 and a C-shaped iron core 52. Current is applied from a power source 56 to the electromagnet coil 51 via a switch 55. The switch 55 may be an on / off switch or a reversible current-direction changeover switch and is actuated by a switch lever 36 of the actuator 35, for example, when deflected, the switch lever 36 toggles the rocker switch 55, as symbolically indicated by the arrows. In the air gap between these free ends of the C-shaped iron core 52, adjustment pieces 53 are arranged as adjustment elements 24, and adjustment magnets 24b, 24c designed as permanent magnets are mounted on the adjustment pieces 53 in a manner opposite to each other. Depending on the polarity of the adjusting magnets 24b and 24c and the direction of the current through the electromagnet coil 51, the adjusting plate 53 repels or attracts one or the other free end of the C-shaped iron core. If the switch 55 is designed as an on / off switch, the adjusting plate 53 is pre-tensioned to the basic position by a spring (not shown) and deflects from the basic position via magnetic connection when current is applied to the electromagnet coil 51. The adjusting plate 53 is securely connected to the first comb 22, which is movably arranged in the comb holder 22c, and the first comb 22 is repeatedly moved between two end positions. It should be emphasized that the adjusting plate 53, or the adjusting magnets 24b and 24c respectively arranged on it, never comes into contact with the iron core 52. Even when the adjusting plate 53 has reached the end position, a gap 54 is always maintained between these adjusting magnets 24b and 24c and the iron core 52. In other words, the magnetic adjustment of the adjusting plate 53 occurs in a non-contact manner through the actuator magnets. If the aforementioned stop elements restrict the movement of the first comb 22, the magnetic adjustment of the adjusting piece 53 can also be ensured to be non-contact under all operating conditions. This is particularly relevant if the adjusting magnets 24b, 24c and the actuator magnet operate in an "attractive pole setting". The air gap between these free ends of the C-shaped iron core 52 is sized so that the adjusting piece 53, as the adjusting element 24, can always move perfectly and non-contactly in the air gap during shed forming, taking into account not only reciprocating motion but also up-and-down motion.

[0044] Figures 7a and 7b show another embodiment of the shed forming apparatus 10, which, in contrast to the embodiment in Figures 6a and 6b, has a rocker arm with an adjusting magnet 24b as an adjusting element 24, which pivots the first comb 22 (which is pivotally mounted in the comb holder 22c) between two end positions when the adjusting element 24 is repelled or attracted by the actuator magnet 50. Actuation of the first comb 22 is accomplished—similar to the variations in Figures 3 through 5—by means of an eccentric bolt, which is guided through a through-hole drilled in the comb holder 22c and placed in a suitable drilled hole provided for it in the first comb 22. The eccentricity of the eccentric bolt determines the path traveled by the first comb 22 in its pivoting movement, a path shorter than that in alternative embodiments, as shown, for example, in Figures 6a and 6b.

[0045] Regarding the adjusting magnet 24b, it should be mentioned that it is also conceivable to provide two adjusting magnets to the rocker arm. Also applicable to this embodiment is that the adjusting element 24 is pre-tensioned to its basic position by a spring (not shown), and when current is applied to the electromagnet coil 51, the adjusting element 24 is magnetically deflected from its basic position. In this embodiment, the magnetic adjustment of the first comb 22 also occurs in a non-contact manner. [Simplified Explanation of the Diagram]

[0028] Further advantageous designs of the present invention will become apparent from the following description and drawings.

[0029] [Fig. 1] shows a side view of the circular loom according to the present invention. [Fig. 2] shows a top view of the circular loom in Fig. 1. [Figs. 3a, 3b and 3c] show the movement sequence of the belt lifting element during the production of leno fabric. [Fig. 4a] shows a side view of the shed forming device of the circular loom in Fig. 1. [Figs. 4b and 4c] show two variations of the shed forming device in Fig. 4a, top views. [Figs. 5a and 5b] show perspective views of the shed forming device in Fig. 4a. [Figs. 6a and 6b] show a top view and perspective view of an embodiment of the shed forming device according to the present invention, wherein the actuator has an actuator magnet designed as an electromagnet. [Figs. 7a and 7b] show a top view and perspective view of an embodiment of the shed forming device according to the present invention, wherein the actuator has an actuator magnet designed as an electromagnet. [Fig. 8] shows a leno fabric produced by the circular loom according to the present invention.

Claims

1. A shed forming apparatus (10) for a circular loom (1) having warp belt lifting elements (20, 21) arranged in a first group and a second group for guiding warp belts (5, 6) in two warp belt groups (11, 12), wherein the warp belt lifting elements (20, 21) of the first group and the second group give the two warp belt groups (11, 12) an alternating relative movement to each other to form a shed (40), wherein at least one adjusting element (24) engages at least one of the warp belt lifting elements (20, 21) of the groups, the adjusting element giving the warp belt lifting elements (20, 21) a transverse reciprocating movement between a first end position where adjacent warp belts (5, 6) of the two warp belt groups (11, 12) do not intersect each other and a second end position where adjacent warp belts (5, 6) of the two warp belt groups (11, 12) always intersect each other longitudinally, characterized in that, The adjustment element (24) is adjusted in a non-contact manner via an actuator (35), wherein the adjustment element (24) has at least one adjustment magnet (24b, 24c), which repels or attracts the actuator (35) in a non-contact manner through a magnetic interaction relationship.

2. The shed forming apparatus as claimed in claim 1, characterized in that the adjusting magnets (24b, 24c) are designed as permanent magnets.

3. The shed forming apparatus as claimed in either claim 1 or 2, characterized in that the actuator (35) has at least one actuator magnet (35a, 35b) designed as a permanent magnet and is capable of inducing or disintegrating a magnetic interaction with the at least one adjusting magnet (24b, 24c).

4. The shed forming apparatus as claimed in claim 3, characterized in that the actuator (35) includes a switch rod (36), preferably designed as a pivot rod, wherein at least one actuator magnet (35a, 35b) is arranged on the switch rod (36) in such a way that it can be connected or disconnected from a magnetic action by moving the switch rod (36) with the at least one adjusting magnet (24b, 24c).

5. The shed forming apparatus as claimed in claim 4, characterized in that the switch lever (36) is mounted in a pivot bearing (37) and pre-tensioned to a defined position by a leg spring (38).

6. The shed forming apparatus as claimed in either claim 1 or 2, characterized in that the adjusting element (24) has two adjusting magnets (24b, 24c) spaced apart from each other and is capable of alternately inducing a magnetic interaction with the actuator (35) so as to adjust the adjusting element (24) in such a way that the belt lifting elements (20, 21) of the group are assigned to move back and forth between the first end position and the second end position.

7. The shed forming apparatus as claimed in any one of claims 1 or 2, characterized in that the actuator (35) includes at least one actuator magnet (50) designed as an electromagnet, the adjusting magnets (24b, 24c) attracting or repelling the actuator magnet (50) by applying current to the actuator magnet (50), the actuator (35) preferably having a switching lever (36) for applying current to the actuator magnet (50).

8. The shed forming apparatus as claimed in any one of claims 1 or 2, characterized in that the actuator (35) includes at least one actuator magnet (50) designed as an electromagnet, the adjusting magnet (24b, 24c) attracting or repelling the actuator magnet (50) by applying current to the actuator magnet (50), the actuator (35) preferably having a switching lever (36) for reversing the direction of the current applied to the actuator magnet (50).

9. The shed forming apparatus as described in any one of claims 1 or 2 above, characterized in that the warp lifting elements (20) of the first group are formed by the teeth (22a) of a first comb (22), and the eyelets (22b) for guiding the warp are formed on the teeth (22a), while the warp lifting elements (21) of the second group are formed by the teeth (23a) of a second comb (23), wherein the first comb (22) or the second comb (23) is alternately reciprocated between the first end position and the second end position by the adjusting element (24).

10. The shed forming apparatus as described in any one of claims 1 or 2 above, characterized in that the shed forming apparatus includes stop elements (33, 34) defining the positions of the first end position and the second end position, wherein the stop elements (33, 34) are made of a damping material or a damping material (33a, 34a) is provided on their surfaces, the damping material (33a, 34a) preferably being a natural or artificial elastomer.

11. A circular loom (1) comprising: a reed (4), warp guide elements (8) arranged around the reed (4) for supplying a plurality of warp tapes (5, 6) to the circular loom (1), a shuttle (9) circulating within the reed (4) for inserting a weft tape (61) into a shed (40) formed by the warp tapes (5, 6), and a main drive (18) for driving the shuttle (9), the circular loom (1) comprising a shed forming device (10) as described in any one of claims 1 to 10, arranged around the reed (4).

12. The circular loom as claimed in claim 11, characterized in that a control cam frame (17) is driven by the main drive (18), a lifting control cam (17d) is formed on the control cam frame (17) and is used to control the warp lifting elements (20, 21) of the first group and the second group, an actuator control cam (17e) is formed on the control cam frame (17) and is used to control the actuator (35), and the lifting control cam (17d) and the actuator control cam (17e) are preferably integrally formed on the control cam frame (17).

13. A circular loom as claimed in any one of claims 11 or 12, characterized in that the circular reed (4) has a plurality of reeds (4a) and spacers (4b), some of the reeds (4a) being arranged alternately with at least one spacer (4b), adjacent reeds (4a), adjacent reeds (4a) and spacers (4b) being arranged in the circular reed (4) at equal distances from each other and having the same width.

14. Use of a circular loom (1) as described in any one of claims 11 to 13 for producing a leno fabric (60).

15. A method for forming a shed (40) in a circular loom (1), wherein: A plurality of warp strips (5, 6) to two warp strip groups (11, 12) are provided, and the two warp strip groups (11, 12) are given an alternating relative movement to form the shed (40). At least one set of the two warp strip groups (11, 12) is given a lateral reciprocating movement between a first end position where adjacent warp strips (5, 6) of the two warp strip groups (11, 12) do not intersect each other and a second end position where adjacent warp strips (5, 6) of the two warp strip groups (11, 12) always intersect each other longitudinally. The feature is that... At least one set of the lateral reciprocating motions given to the two belt sets (11, 12) is performed in a non-contact manner via an adjusting element (24), which is adjusted in a non-contact manner by an actuator (35), wherein the adjusting element (24) has at least one adjusting magnet (24b, 24c), which is repelled or attracted by the actuator (35) by magnetic interaction.

Images