The method involves wrapping a first linear object with a second linear object, a torsion module, and a torsion machine.

Abstract

The invention relates to a method of winding a first linear object with a second linear object. The method comprises the following steps: positioning the first linear object; positioning the second linear object on a spool with a rotating shaft parallel to the first linear object; unwinding the second linear object from the spool; and bringing the two linear objects into contact at the winding point, such that the two objects form an acute angle with each other. Both linear objects can be held under speed and / or tension control throughout the process to control the winding angle.

Description

[0001] Twisting machine

[0002] Description:

[0003] The present application pertains to a twisting module, a twisting machine comprising such a module and a method for wrapping a second linear body around a first linear body.

[0004] Twisting of fibers and threads in order to obtain stable and processable yams is a cultural achievement of humankind that is already millennia old. As long as these techniques are practiced, they secure a supply of processable yarns for the production of woven or knitted fabric, mainly for clothing and other textile applications.

[0005] Apart from clothing and related textile applications, the past decades have seen an increasing use of textile products such as woven or knitted but also nonwoven fabrics for the purpose of reinforcement of products which, at least at their surfaces, are from non-textile materials. One prominent example of such a product are tires which are not only inflated balloons of rubber but which also comprise different and sophisticated textile reinforcement which only becomes visible to the user when the tire is destroyed.

[0006] Typical tires comprise a large amount of steel wire as reinforcement, however steel wire has the disadvantage of adding a large amount of weight to the tire resulting in higher fuel consumption of the vehicle the tire is equipped with. It is thus a goal of current research to develop materials and structures which are able to replace steel wire as main material in the reinforcement of tires. For this purpose, the applicant of the present invention has recently presented reinforcement wires which are mainly made from polymeric materials. The main feature of said wires is a monolithic core of a polymeric material which is wrapped with reinforcement fibers. Details on this subject matter can be found in WO2022 / 184917A1 which is hereby incorporated by reference into the present application in its entirety.

[0007] Twisting techniques for reinforcement fibers differ in certain points from traditional twisting techniques which form yams out of staple fibers which in the twisting process have to be ordered and aligned prior to twisting. For staple fibers, the twist is indispensable for connecting the fibers to each other in order to get a stable yarn.

[0008] As a contrast, modem reinforcement fibers are typically filaments which means that they have a length which is more or less infinite in relation to their thickness. While typical staple fibers have a length of some few centimeters, a typical filament may have a length of several hundred meters or even many kilometers. In principle, it is imaginable that the content of a whole yam bobbin consists of only one single filament.

[0009] In general and throughout the present application, filaments are considered to be a special kind of fibers. It is furthermore understood that this definition of filaments and fibers also encompasses metal wires.

[0010] In contrast to staple fibers, filaments can be connected to yams in several manners apart from twisting, e.g. by point-welding or point-gluing. However, also concerning filaments, twisting is still an important technique to achieve stable yams. Especially for tire reinforcement, twisted yams play an important role and are typically termed “cords”. In tire reinforcement a typical cord consists of several yams which by themselves may be twisted and which yams are twisted together to form the cord. In a cord, typically all yams contributing thereto are involved in the twist.

[0011] The distinction between fibers and filaments outlined above is considered to hold for the entire application.

[0012] There are special kinds of cords which comprise a central strand which is not involved in the twist and which is wrapped with other strands or yams. The strands or yarns which are wrapped around the central strand or yarn are called outer strands or yarns.

[0013] Throughout the present application, cords obtained by this technique are also called “cables”.

[0014] Throughout this application, the term “cable” means a cable as outlined in the preceding paragraph which is not the same as an electrical cable which comprises at least one electrical conductor surrounded by an isolation. If an electrical cable is meant, this is indicated explicitly.

[0015] A big challenge in making cables (known by the skilled person as “cabling”) is to carry out the wrapping without twisting the central strand or yam, i.e. without the central strand or yarn and thus also the complete product with a residual torsion that is too high. The residual torsion, which can be determined according to ASTM D2969-02 is a mechanical property of cords which drastically limits its use especially in tire production. Thus, in cord production, efforts are put into minimization of the residual torsion.

[0016] This becomes even more difficult if materials with different tensile moduli or elongations at break are to be processed on the same machine. Thus, the compatibility of cabling machines with materials of different tensile moduli or elongations at break is rather low and leads to big variations in the quality of the product obtained. It is thus the object of the present invention to provide a method and devices for an improved cabling process which increases the compatibility of cabling machines with different materials and leads to a constant and reproducible product quality.

[0017] The problem is solved by a method for wrapping a first linear body with a second linear body comprising the steps of providing a first linear body between two fixation points with the straight line between the two fixation points forming a neutral axis, putting the first linear body under speed control and / or tension control, providing a second linear body on a bobbin with the bobbin having a rotational axis parallel to the first linear body, unrolling the second linear body from the bobbin under speed control and / or tension control, contacting the first linear body and the second linear body at a wrapping point , the wrapping point being positioned in such a manner that the first linear body forms an angle a of at most 1 .5° on both sides of the neutral axis, the wrapping point is located in the central third of the length of the first linear body between the two fixation points, the second linear body forms an angle [3 with the neutral axis which is between 30° and 70°, using speed and / or tension control of both the first and the second linear body to steer the angle [3 and the position of the wrapping point.

[0018] According to the present application the term “linear body” is not particularly limited and can mean any body that has a length that is at least a hundred times its diameter and that is flexible enough that it can be wrapped around a body of similar or lower diameter. For example a linear body can be a fiber, a filament, a wire, a yam or any other strand-like structure known to the person skilled in the art.

[0019] It is important to mention that the linear body according to the application is not limited according to its structure. It may thus be a monolithic structure, a hollow structure, a structure comprising one or more filaments, fibers or yams which may be connected by gluing, twisting or welding or it may be a structure where fibers or filaments are embedded into a different non-fibrous material. In an embodiment, a linear body may be a strand of parallel filaments, a twisted yam, a monolithic body made of a polymer or a body made of a polymer with a strand of parallel filaments or a twisted yam embedded therein.

[0020] It is furthermore important to note that these considerations are true for both the first and the second linear body. However, it is further understood that the first and the second linear body may have the same or different material characteristics. The fibers, filaments and / or the other materials such as coatings, coverings or adhesives comprised in the first linear body can be of any organic polymer or inorganic material known in the art. Possible inorganic materials are aluminum, steel, glass, carbon or basalt. Possible organic polymers are thermoplastic and / or thermosetting polymers such as polyesters (polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyethylene furanoate (PEF), and the like), aromatic polyesters, aliphatic polyamides (such as polyamide-5, polyamide-6, polyam ide-6,6, polyamide-5,6, polyam ide-4, 10, polyam ide-6, 10, polyamide-6,8, polyam ide-10 or polyam ide-11 ), aromatic polyamides such as aramids (parapolyphenylene terephthalamide, meta-polyphenylene isophthalamide), polyvinyl alcohol, polyvinyl acetate, polyphenylene benzobisoxazole (PBO), polybenzimidazole (PBI), polyetheretherketone (PEEK), ultra-high molecular weight polyethylene (UHMWPE), polyurethane (PUR) or copolymers comprising monomers of said materials or mixtures or blends of said materials but is not limited to this selection.

[0021] The material of the first linear body may have elastomeric properties, namely thermoplastic elastomeric properties which means that it is formed from molecular chains which are interconnected by non-bonding interactions at room temperature, providing them with elastomeric properties. Typical thermoplastic elastomers are polyurethanes with long polyol chain contributions or thermoplastic elastomers of the polyester-ester or the polyether-ether type. Typical product names are Elasthan, Spandex and Lycra®.

[0022] The material of the first linear body may in part or completely be of biological origin. The material of the first linear body may thus also be cellulosic or proteinic fibers such as cotton fibers, viscose fibers, lyocell fibers, linen fibers, hemp fibers, abace fibers, sisal fibers, wool fibers of sheep, goats or any other mammals or silk fibers from the cocoons of the species Bombyx mori or from any other insects that produces suitable fibers. The material of the first linear body may in part or completely be made from recycled plastics. Materials of biological and recycling sources may be combined.

[0023] In an embodiment, the first linear body may comprise a nucleating agent. Said nucleating agent may be talc or a similar inorganic filler, sodium benzoate, sodium stearate, sodium-ion ionomers, a sulfonamide compound metal salt or a sulfonimide compound metal salt, mono sodium salt of dicarboxylic acid, and mixtures thereof, as known in the art.

[0024] The first linear body may furthermore comprise an adhesion promotion agent. The skilled person knows this also under the term “dip” or “dipping”. Said adhesion promotion agent may e.g. be the so-called RFL-dip comprising resorcinol, formaldehyde and latex or any other adhesion promoting agent which may e.g. be acrylic polymers, isocyanates, epoxides, polyols or other agents known to the person skilled in the art.

[0025] The diameter of the first linear body is at least 0.3 mm. In an embodiment, the diameter of the first linear body is at least 0.4 mm. In an embodiment, the diameter of the first linear body is at least 0.6 mm. In an embodiment, the diameter of the first linear body is at least 0.8 mm. In an embodiment, the diameter of the first linear body is at least 1 .0 mm. In an embodiment, the diameter of the first linear body is at least 1 .2 mm. In an embodiment, the diameter of the first linear body is at least 1 .4 mm. In an embodiment, the diameter of the first linear body is at least 1 .6 mm. In an embodiment, the diameter of the first linear body is at least 1 .8 mm. In an embodiment, the diameter of the first linear body is at least 2.0 mm. In an embodiment, the diameter of the first linear body is at least 2.3 mm.

[0026] The diameter of the first linear body is at most 2.5 mm. In an embodiment, the diameter of the first linear body is at most 2.3 mm. In an embodiment, the diameter of the first linear body is at most 2.1 mm. In an embodiment, the diameter of the first linear body is at most 1 .9 mm. In an embodiment, the diameter of the first linear body is at most 1 .7 mm. In an embodiment, the diameter of the first linear body is at most 1 .5 mm. In an embodiment, the diameter of the first linear body is at most 0.9 mm. In an embodiment, the diameter of the first linear body is at most 0.7 mm. In an embodiment, the diameter of the first linear body is at most 0.5 mm. The first linear body may comprise one or more reinforcement threads which may be essentially parallel and which may be embedded into a polymeric matrix material.

[0027] It is understood that although these considerations have been made for the first linear body, the second linear body may have the same characteristics or different characteristics. However the characteristics of the second linear body may be selected from the same catalogue as the ones of the first linear body.

[0028] Furthermore, the skilled person knows that any selection from said catalogue for the first linear body may be combined with any selection from the second linear body. The term “fixation point” according to the present application means members between which the first linear body can be guided in such a manner that its moving speed and / or tension can be controlled. The term “fixation point” does explicitly not mean that the first linear body is connected to said points in such a manner that it is no longer able to move. However, it means a point where tension control and / or speed control is exerted to a linear body. The fixation points according to the present application may thus be connected to rollers, loops or hooks but also godets and pairs, triples or other multiples of godets over which the first linear body may be guided and which may be able to control the speed and / or the tension of first linear body. More explicitly, a fixation point is the point where the first linear body gets in contact with the roller, loop, hook, godet or multiple of godets and / or leaves the roller, hook, loop, godet or multiple of godets.

[0029] The straight line between the two fixation points is called “neutral axis”. It is important to note that the neutral axis is an imaginary line. However, in an embodiment, the first linear body may be kept under such a tension that it is essentially parallel to or colinear with the neutral axis in case no other forces effect the first linear body. “Essentially parallel” according to the present application means that the position of the first linear body does not deviate from the neutral axis by more than 1 % of the length of the neutral axis.

[0030] The second linear body may comprise reinforcement threads which may be monofilaments, yarns or cords.

[0031] If the reinforcement threads are yams, the yarns may be twisted or untwisted. Twisted yams typically have an essentially round cross section filaments. Twisted yams may be twisted in S- or in Z-direction. Yams which are not twisted may also have other cross section geometries such as rectangular, oblong or oval or they may have a ribbon-like shape. The skilled person knows ribbon-like shaped yams also as “flat yams” or “ribbon-yarns”. If the reinforcement threads are cords, the cords may be formed from two or more yams twisted together. In a cord of twisted yams, typically, the yams have S-twist and they are twisted together in Z-twist or the yams have Z-twist and are twisted together in S-twist. Cords may also be twisted from e.g. two yams with one having S-twist and one having Z-twist. Cords can also be made from untwisted yams which untwisted yams are twisted together. A cord may also comprise both twisted and untwisted yams or any combination of twisted yams, untwisted yams and monofilaments. It is understood that this definition of cords holds through the entire application and is not limited to cords comprised in the first linear body.

[0032] The fibers, filaments and / or the other materials such as coatings, coverings or adhesives comprised in the second linear body can be of any organic polymer or inorganic material known in the art. Possible inorganic materials are aluminum, steel, glass, carbon or basalt. Possible organic polymers are thermoplastic and / or thermosetting polymers such as polyesters (polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyethylene furanoate (PEF), and the like), aromatic polyesters, aliphatic polyamides (such as polyamide-5, polyamide-6, polyamide-6,6, polyamide-5, 6, polyam ide-4, 10, polyamide-6, 10, polyamide-6, 8, polyam ide-10 or polyam ide-11 ), aromatic polyamides such as aramids (parapolyphenylene terephthalamide, meta-polyphenylene isophthalamide), polyvinyl alcohol, polyvinyl acetate, polyphenylene benzobisoxazole (PBO), polybenzimidazole (PBI), polyetheretherketone (PEEK), ultra high molecular weight polyethylene (UHMWPE), polyurethane (PUR) or copolymers comprising monomers of said materials or mixtures or blends of said materials but is not limited to this selection.

[0033] The material of the second linear body may have elastomeric properties, namely thermoplastic elastomeric properties which means that it is formed from molecular chains which are interconnected by non-bonding interactions at room temperature, providing them with elastomeric properties. Typical thermoplastic elastomers are polyurethanes with long polyol chain contributions or thermoplastic elastomers of the polyester-ester or the polyether-ether type. Typical product names are Elasthan, Spandex and Lycra®.

[0034] The material of the second linear body may in part or completely be of biological origin. The material of the second linear body may thus also be cellulosic or proteinic fibers such as cotton fibers, linen fibers, hemp fibers, abaca fibers, sisal fibers, wool fibers of sheep, goats or any other mammals or silk fibers from the cocoons of the species Bombyx mori or from any other insects that produces suitable fibers. The material of the second linear body may in part or completely be made from recycled plastics. Materials of biological and recycling sources may be combined.

[0035] In an embodiment, the second linear body may comprise a nucleating agent. Said nucleating agent may be talc or a similar inorganic filler, sodium benzoate, sodium stearate, sodium-ion ionomers, a sulfonamide compound metal salt or a sulfonimide compound metal salt, mono sodium salt of dicarboxylic acid, and mixtures thereof, as known in the art.

[0036] The second linear body may furthermore comprise an adhesion promotion agent. The skilled person knows this also under the term “dip” or “dipping”. Said adhesion promotion agent may e.g. be the so-called RFL-dip comprising resorcinol, formaldehyde and latex or any other adhesion promoting agent which may e.g. be acrylic polymers, isocyanates, epoxides, polyols or other agents known to the person skilled in the art.

[0037] It is understood that although these considerations have been made for the second linear body, the first linear body may have the same characteristics. Throughout the application, the term “linear body” without “first” and “second” means that the consideration holds true for both the first and the second linear body.

[0038] It is furthermore understood that the distinction between first and second linear body is only a matter of whether the linear body is wrapped around another linear body. This means that once, a second linear body has been wrapped around the first linear body, it becomes part of the first linear body. This is especially important for cases where several wrapping procedures are carried out one after another. Speed control according to the present application means that the speed of a linear body is permanently measured and can be adapted during the wrapping process. Speed control requires that the speed of a linear body can actively be reduced and increased and that means for these purposes are present. Furthermore, speed control requires that the speed of a linear body can be measured in order to be able to reduce or increase the speed of the linear body. Means for speed reduction and for the increasing of speed may be different or the same. For speed reduction, friction-based brakes may be used while for increasing of the speed rollers may be used on which the linear body is wrapped and which rollers can be driven at variable speed. A typical means for driving such rollers is an electric motor. In an embodiment, such electric motor can also be used as a dynamic brake. In the latter case, the electric motor is switched to a mode where it no longer works as an electric motor but as an electric generator and converts mechanical energy into electric energy while reducing the rotational speed of the roller.

[0039] The roller may be a godet and such be a part of a pair, a triple or any multiple of godets.

[0040] Tension control according to the present application means that the tension of a linear body is permanently measured and can be adapted during the wrapping process. Tension control requires that the linear body can actively be strained and released. Tension control requires that means for this purpose are present. Typical means for tension control are pairs, triples or any other multiples of godets which can be driven at different speeds depending on whether the linear body has to be strained or released. In order to steer the tension of a linear body, godets may be driven in such a way that their rotation speed can actively be reduced and increased. In an embodiment, the godets may be driven by an electric motor. In an embodiment, such electric motor can also be used as a dynamic brake. In the latter case, the electric motor is switched to a mode where it no longer works as an electric motor but as an electric generator and converts mechanical energy into electric energy while reducing the rotational speed of the roller. Furthermore, other techniques of tension control may be used which are known to the person skilled in the art. In mechanical systems, a godet is coupled with a weight that is absorbing the differences in tension similar to the system used for the tension control of overhead lines for railroad tracks. Also pneumatic, hydraulic and magnetic tension control systems may be used. Speed control and tension control may be carried out by the same means, e.g. by the same pair, triple or any other multiple of godets. It is important to notice that there is no direct relationship between speed and tension as long as the stretchability of the linear body is not taken into account.

[0041] Speed and tension control may also be carried out independently of each other and may be activated and deactivated independently of each other for both the first and the second linear body. In an embodiment, the first linear body may be put under speed control while the second linear body may be put under tension control.

[0042] In an embodiment, the first linear body may be put under tension control while the second linear body may be put under speed control.

[0043] In an embodiment, both the first and the second linear body may be put under both speed and tension control.

[0044] In an embodiment, during the wrapping process, it may vary whether the first and / or the second linear body are put under speed control and / or tension control. Apart from means for speed control and means for tension control, the twisting machine according to the present application may comprise further units which have beneficial effects on either the process carried out on the machine or to the final product obtained from the machine.

[0045] The twisting machine according to the present application may comprise one or more linearity balancing systems which compensate for errors in the linearity of the wrapped material. Deviations from linearity are typical for materials which show a certain amount of stiffness, especially if they contain any kind of metal. A linearity balancing system is a series of slightly misaligned rolls through which the material is passed and which compensates for the deviations from the linearity.

[0046] In an embodiment, the twisting machine according to the application may comprise one or more residual torsion balancing systems. A residual torsion balancing system comprises a multiple of rolls between which the material is guided through. Said rolls are mounted to a rotatable carrier which is shaped like the letter “U”. The rolls on the support are rotatable around an axis which is parallel to the moving axis of the material and the neutral axis. By rotation around said axis, the residual torsion balancing system may provide counter rotation to the material passing through it in order to compensate for the residual torsion.

[0047] Residual torsion balancing systems are especially efficient for materials which comprise metal e.g. in the form of wires.

[0048] In an embodiment, the wrapping machine according to the present application may comprise a shaping system which comprises one or more texturized rollers through which the material can be guided and which have the purpose of texturizing the material e.g. to a wavy shape in order to make the material e.g. more extendable by giving it a waved or zig-zag structure. A cord with such a structure shows similar properties as a spring. A shaping system is especially efficient for materials that comprise metals.

[0049] In general all mentioned systems may occur in the twisting machine as often as necessary and at any position where they are needed. The skilled person furthermore knows that they can be combined with each other and with the other systems of the machine in essentially any reasonable manner.

[0050] A bobbin according to the present application is a body of circular cross section which allows for a lengthy item such as a linear body being rolled thereon. In general, any known body on which lengthy items can be rolled can be considered a bobbin according to the present application. In an embodiment, a bobbin comprises a cylindrical body on which a linear body is rolled and at its edges plates of a diameter larger than the one of the cylindrical body in order to make sure that the linear body does not slide off the bobbin. The amount of linear body that is rolled to a bobbin is not particularly limited. Depending on the size of the bobbin and the dimensions of the linear body, a bobbin may take several hundred meters or even several to many kilometers of a linear body.

[0051] As rolling requires rotation, a bobbin according to the present application has a rotational axis. In case the body of the bobbin has cylindrical shape, the rotational axis of the bobbin is the central axis of the cylinder. It is important to note that the term “rotational axis” according to the present application does not necessarily mean a physical axis as a component part but also the axis as an imaginary line in mathematical sense. This is especially the case when the body of the bobbin is hollow and the bobbin is mounted onto a physical axis for any kind of processing. In the process according to the present application, the bobbin with the second linear body is provided in such a way that its rotational axis is parallel to the first linear body. The first linear body may thus be guided such that it forms essentially a straight line when it passes by the bobbin with the second linear body.

[0052] Unrolling of the second linear body may be carried out in two different manners known to the skilled person as “defile” mode and “deroule” mode. In the defile mode, the second linear body is unrolled from the bobbin while the bobbin stands still. In such a case, unrolling may be carried out using an arm which rotates around the bobbin and picks up the second linear body which is guided by guiding means such as rings, hooks, bails or lugs. Unwinding may be carried out clockwise or counterclockwise.

[0053] In the “deroule” mode, the second linear body is unwound from the bobbin whereby the bobbin rotates. Unwinding may be carried out clockwise or counterclockwise. Also in deroule-mode the unwinding can be assisted by a rotating arm which guides the second linear body.

[0054] After unwinding, the second linear body is guided in such a way that the second linear body approaches and contacts the first linear body in an acute angle [3 at a position called the wrapping point and is wrapped around the first linear body. During the wrapping process, speed control and / or tension control may be provided to the first and / or the second linear body in order to steer the angle [3 and the position of the wrapping point. The relevant angles are shown in Fig. 7. Wrapping can be carried out in clockwise or counterclockwise rotation. Furthermore, the speed and / or tension of the first and the second linear body are controlled in such a manner that the wrapping point is within the central third of the length of the first linear body between the fixation points. Tension and speed control of the first and the second linear body make sure that during the wrapping process, the first linear body forms an angle of at most 1 .5° with the neutral axis and that the angle [3 the second linear body forms with the neutral axis is between 30° and 70°. It is noted that during the wrapping process, the second linear body does not necessarily cross with the neutral axis. In such case, the angle [3 is the angle of the extrapolation of the second linear body onto the neutral axis.

[0055] In an embodiment, the maximum deviation between the wrapping point and the neutral axis is 4 millimeters. In an embodiment, the maximum deviation between the wrapping point and the neutral axis is 2 millimeters, 1 millimeter or 0.5 millimeters.

[0056] Keeping the wrapping point constant is important to assure that the finally processed wrapped yam has homogeneous mechanical properties, namely a homogeneous residual torsion which can be measured according to ASTM D2969- 02 which is a property fundamental for the processability of cords, especially to tire reinforcements. By using a twisting machine according to the present application, the residual torsion of the readily processed yam can be adjusted properly.

[0057] In an embodiment, several second linear bodies are wrapped around the first linear body forming different layers. In such case, typically, alternating layers have alternating rotation directions in the wrapping.

[0058] In an embodiment, by steering the angle [3 and the wrapping point, the angle [3 may be kept constant. In an embodiment “constant” means that the angle [3 does not vary by more than ±1 ° or by not more than ±0.5°.

[0059] In an embodiment, the first linear body may be guided through the bobbin with the second linear body. In such case, the rotation axis of the bobbin may be collinear with the first linear body. This embodiment allows for an especially compact construction of the corresponding wrapping module.

[0060] In an embodiment, the bobbin with the second linear body rotates around the first linear body. In such case, the bobbin may be provided on a rotatable support. A rotatable support may keep more than one bobbin with second linear bodies of the same or different kinds which may be wrapped around the first linear body. In such case, several second linear bodies may be wrapped around the first linear body. In an embodiment, the several second linear bodies may be wrapped around the first linear body in such a way that they form a closed layer on the first linear body.

[0061] Using one or more additional rotatable supports disposed one after the other and coaxial with the main first linear body, which may rotate in different directions, different layers of second linear bodies may be provided to the first linear body. In an embodiment, the wrapping process is carried out using two bobbins with second linear bodies being provided on one rotational support which contact the first linear body from exactly opposite sides under the same tension. This results in a wrapping procedure where the first linear body does not deviate from the neutral position at the wrapping points allowing for a very efficient manner to avoid providing it with residual torsion during the wrapping process.

[0062] In another embodiment, the wrapping process is carried out with more than two bobbins at the same time which are mounted on the same rotatable support. In order to make sure that the wrapping is carried out in a balanced manner, the bobbins should then be arranged on the rotatable support in such a manner that they have the same distance to the wrapping point and they are arranged in regular angles to each other which angles depend on the amount of bobbins. So, two bobbins should form an angle of 180° with each other on the rotational support, three bobbins should form angles of 120° with each other, four bobbins should form an angle of 90° with each other, five bobbins should form an angle of 72° with each other and six bobbins should form an angle of 60° with each other. This balanced arrangement of the bobbins on the rotatable support is important in order to avoid imbalances and to keep the wrapping point balanced. During the wrapping process, the rotatable support reaches rotation rates in the range of 500 to 6000 turns per minute, in case it is well balanced in the range of 500 to 8000 rpm, which - in the case the bobbins would not be arranged in such balanced manner - result in a severe imbalance due to the high rotation rate which would lead to strong vibrations and a high mechanical wear up to even demolition of the twisting module.

[0063] In all the possible wrapping methods above described, for wrapping single or multiple second linear bodies around a first linear body, the layer of second linear body / bodies around the first linear body may provide both a close coverage of the first linear body or a partial coverage of the first linear body. In an embodiment, the distance between the rotational axis of the bobbin and the first linear body may be variable. This means that different bobbins may be provided in different distances to the first linear body and / or that the distance between the rotational axis of a bobbin and the first linear body may be varied during the wrapping process.

[0064] The application further pertains to a twisting module suitable for carrying out the process according to the application, the module comprising means for guiding a first linear body in a first axis under tension control and / or speed control between two fixation points, at least one mount suitable for taking at least one bobbin, the bobbin comprising a second axis, means for guiding a second linear body under tension control and / or speed control while the second linear body is unwound from the bobbin, means for wrapping the second linear body around the first linear body under tension control and / or speed control.

[0065] A module according to the present application is an autonomous device that comprises all components which are necessary to carry out the wrapping process according to the present application.

[0066] Guiding means according to the present application may be single rollers or arrays of rollers as well as rings, hooks, bails or lugs through which the second linear body is guided. In an embodiment, the guiding means comprise at least one pair, triple or any other multiple of godets. In an embodiment, the godets may be driven by an electric motor. In an embodiment, such electric motor can also be used as a dynamic brake. In the latter case, the electric motor is switched to a mode where it no longer works as an electric motor but as an electric generator and converts mechanical energy into electric energy while reducing the rotational speed of the roller.

[0067] The guiding means according to the present application have so-called fixation points. A fixation point is the point of first contact between the guiding means and a linear body, i.e. the point where the effect of the guiding means is felt by the linear body for the first time. It is pointed out that “fixation point” does not mean that a linear body is fixed at said point in such a manner that it cannot move. However, it means a point where tension control and / or speed control is exerted to a linear body. The first linear body may be wrapped around the godets e.g. in the shape of the number “8” in case of a pair of godets. The godets offer a means for controlling the speed and / or the tension of the first linear body and they decouple the first linear body in the sense of tension and speed from any preceding devices. The first linear body may be provided by unwinding from a bobbin. Then a pair, triple or multiple of godets or any other means for tension control and speed control decouples the first linear body from the speed and tension circumstances in the unwinding section. Thus, the unwinding does not necessarily have to be steered at the same level of precision as the wrapping process but can be carried out more flexibly.

[0068] The guiding means make sure that the first linear body is guided in an essentially straight line which is called the “first axis” in the present application.

[0069] A mount according to the present application may be any kind of shaft on which the bobbin may be mounted as long as the bobbin has a hollow core. The shaft may be equipped in such a manner that it clamps the bobbin e.g. by friction fit in such a manner that the bobbin takes over a rotation which may be carried out by the shaft. The shaft may be provided such that the first linear body can be guided through the shaft, or the shaft may be part of a rotatable support which can rotate around the first linear body.

[0070] The bobbin with the second linear body comprises a rotational axis which is called the “second axis” in the present application.

[0071] Furthermore, the module comprises a means for guiding the second linear body under tension control and / or speed control while it is unwound from the bobbin. Said means for guiding may be a rotating arm. Said rotating arm may comprise a pair, a triple or a multiple of godets as means for providing control of speed and tension. In this case, the godets may decouple the second linear body in the sense of tension and speed from the unwinding process. Then a pair, triple or multiple of godets or any other means for tension control and speed control decouples the first linear body from the speed and tension circumstances in the unwinding process. Thus, the unwinding does not necessarily have to be steered at the same level of precision as the wrapping process but can be carried out more flexibly. Furthermore, means are provided for wrapping the second linear body around the first linear body under tension control and / or speed control. It is pointed out that the means for wrapping may be the same means as the means for guiding while it is unwound from the bobbin.

[0072] The mount for the bobbin with the second linear body may be placed such that the first linear body is guided through the mount with the first axis and the second axis being collinear. In such case, the module can be constructed in a very compact manner.

[0073] The mount for the bobbin with the second linear body may be placed such that it can rotate around the first linear body.

[0074] In such case, the mount may be provided on a rotatable support. A rotatable support may keep more than one mount for bobbins with second linear bodies. In such case, several second linear bodies may be wrapped around the first linear body.

[0075] In an embodiment, the distance between the rotational axis of the bobbin and the first linear body may be variable. This means that different mounts may be provided in different distances to the first linear body on the rotatable support and / or that the distance between the rotational axis of a bobbin and the first linear body on the rotational support may be varied during the wrapping process.

[0076] The application further pertains to a twisting machine which comprises at least one twisting module according to the present application. This allows for an easy and modular construction of a twisting machine where each twisting module may carry out one wrapping step which may comprise e.g. wrapping the first linear body with one second linear body while another module wraps the first linear body with a second linear body. In an embodiment, every module comprises a pair, triple or any other multiple of godets at its beginning which serves for decoupling the first linear body from the speed and tension circumstances in the prior module.

[0077] The twisting machine may comprise one central steering unit which may be connected to all means for speed control and tension control comprised in the machine. This allows for central steering of all these parameters in order to control the quality of the final product produced with the machine. Figures

[0078] The figures show possible embodiments of the idea fundamental for the present application. It is understood that the figures are not limiting in any sense and that the idea may occur in different embodiments than the ones depicted here.

[0079] Fig. 1 shows a twisting machine wherein the direction of processing is from right to left. The twisting machine comprises a let off (101 ) which has its own tension regulator system (102). The tension regulator (102) is followed by a braking system (103) which is also part of the tension regulation. The machine comprises two wrapping modules (104) which comprise a wrapping system (104a) and a loading cell for tension regulation(104b). After the wrapping modules (104) another braking system (103) is located followed by linearity balancing systems (107) and a residual torsion balancing system (106) and a shaping system (108). The linearity balancing system (107) is a series of slightly misaligned rollers through which the wrapped material is passed and which compensates for irregularities in the linearity of the material which is of special relevance for materials comprising metal wires.

[0080] The residual torsion balancing system (106) is an array of two rollers through which the wrapped material is passed, and which is rotatable around an axis which is parallel to the axis of the wrapped material in order to compensate for the residual torsion of the wrapped material by providing the material with a counter torsion. This is of special relevance for materials comprising metal wires.

[0081] The shaping system (108) comprises textured rollers which are able to emboss the wrapped material with a pattern or to texture it in its entirety in order to e.g. bring it into a wavy shape. This is of special relevance when the material comprises metal wires.

[0082] These are followed by a motored braking system for tension regulation and a tension regulator (102) for the wind up (111 ).

[0083] Fig. 2 shows a wrapping system 104a in more detail where an incoming first linear body in neutral position 204 is supplied from the right passing through the core of a bobbin 202 with a second linear body 206 which is driven by an axial engine with electronic regulation 203. A wing 205 assist the unrolling of the second linear body 206 from the rotating bobbin which corresponds to the deroule-mode of wrapping. The second linear body 206 is contacted with the first linear body 204 in the wrapping point 201 . It is noted that the first linear body does not visibly leave the neutral position in this embodiment.

[0084] Fig. 3 shows a different embodiment of a wrapping system 104a wherein a first linear body in neutral position 204 is supplied from the right passing through the center of a rotatable support 306 on which support a bobbin 202 with a second linear body 206 is mounted which is driven by an axial engine with electronic regulation 203. Note that the different hatchings denote different positions of one and the same bobbin during the wrapping process. A wing 205 assists the unrolling of the second linear body 206 from the bobbin. The wrapping process may be carried out either in the deroule or in the defile-mode. The second linear body 206 is contacted with the first linear body 204 in the wrapping point 201. It is noted that the first linear body 204 does not visibly leave the neutral position in this embodiment.

[0085] Fig. 4 shows another embodiment of the wrapping system 104a as Fig. 3 in a front view with the first linear body 204 in the very center and the two bobbins 202 second linear bodies 206 rotating around it on the support 360 on exactly opposite sides of the rotational support. In this embodiment, the forces exerted by the wrapping onto the first linear body are compensated in such a manner that the first linear body does not leave its neutral position. Note that the support furthermore comprises two additional positions for further bobbins 402.

[0086] Fig. 5 shows another embodiment of the wrapping system 104a which can be understood as a mixture of the embodiments of Fig. 2 on one side and Figs. 3 and 4 on the other side. In this embodiment, a first linear body in neutral position 204 is guided through a bobbin 202 with a second linear body 206 while another bobbin 202 with another second linear body 206 is mounted to a rotatable support 306. Both bobbins 202 are driven by axial engines with electronic regulation 203. Unrolling of the second linear bodies 206 from the bobbins 202 is assisted by wings 205. The second linear bodies 206 are contacted with the first linear body 204 at the wrapping point 201. It is noted that in this embodiment, the first linear body does not visibly leave the neutral position. It is furthermore noted that different hatchings indicate one and the same bobbin and second linear body at different points in space at different times during processing.

[0087] Fig. 6 shows the embodiment of Fig. 5 in a front view with the first linear body 204 being guided into the system in the very center passing through a bobbin 202 with a second linear body 206 as well as through a rotatable support 306 with another bobbin 202 with another second linear body 206. The rotatable support 306 has several additional positions 402 for further bobbins.

[0088] Fig. 7 shows the different geometrical quantities being important for the wrapping process. It is important to note that these quantities are relevant for all possible wrapping systems and are not limited to the ones presented either in the description or in the previous figures. It shows the first linear body 204 which between the fixation points A and C deviates from the neutral position (the neutral position would be the straight line between the points A and B) through the wrapping process wherein a second linear body 206 from a bobbin 202 assisted by a wing 205 is wrapped around the first linear body 204 in the wrapping point 201 . Due to the wrapping process, the second linear body 206 exerts a force to the first linear body which induces its deviation from the neutral position. For this reason, in the fixation points A and B, the first linear body forms an angle a with the neutral position while the second linear body forms an angle [3

Claims

Twisting machineClaims:1 . Method for wrapping a first linear body with a second linear body comprising the steps of• providing a first linear body between two fixation points with the straight line between the two fixation points forming a neutral axis,• putting the first linear body under speed control and / or tension control,• providing a second linear body on a bobbin with the bobbin having a rotational axis parallel to the first linear body,• unrolling the second linear body from the bobbin under speed control and / or tension control,• contacting the first linear body and the second linear body at a wrapping point,• the wrapping point being positioned in such a manner that o the first linear body forms an angle a of at most 1 .5° on both sides of the neutral axis, o the wrapping point is located in the central third of the length of the first linear body between the two fixation points, o the second linear body forms an angle [3 with the neutral axis which is between 30° and 70°,• using speed and / or tension control of both the first and the second linear body to steer the angle [3 and the position of the wrapping point.

2. The method of claim 1 wherein the first linear body is guided through the bobbin with the second linear body prior to wrapping.

3. The method of claim 1 wherein the rotational axis of the bobbin with the second linear body rotates around the first linear body.

4. The method of claim 3 wherein additionally the first linear body is guided through the bobbin with the second linear body.

5. The method of any one or more of the previous claims wherein the bobbin with the second linear body is rotating.

6. The method of any one or more of claims 1 -4 wherein the second linear body is unrolled without rotating the bobbin.

7. The method of any one or more of the previous claims wherein the angle [3 is kept in a range of ±1 °, preferably ±0.5° during the wrapping process.

8. A twisting module suitable for carrying out the process according to any one or of claims 1 -7, the module comprising• means for guiding a first linear body in a first axis under tension control and / or speed control between two fixation points,• at least one mount suitable for taking at least one bobbin, the bobbin comprising a second axis,• means for guiding a second linear body under tension control and / or speed control while the second linear body is unwound from the bobbin,• means for wrapping the second linear body around the first linear body under tension control and / or speed control.

9. Twisting module according to claim 8, wherein the first axis and the second axis are collinear.

10. Twisting module according to claim 8 or 9 wherein the mount can rotate around the first axis.11 . Twisting module according to claim 10 wherein the module comprises at least two mounts which can rotate at different speeds.

12. Twisting module according to any one or more of claims 8-11 wherein the means for guiding the first and / or the second linear body under tensioncontrol and / or speed control and / or the means for wrapping the second linear body around the first linear body under tension control and / or speed control comprises at least one pair of godets.

13. Twisting module according to claim 12 wherein the pair of godets is steered electronically and comprises speed sensors and tension sensors.

14. Twisting machine comprising at least one twisting module according to any one or more of claims 8-13.

15. Twisting machine according to claim 14 wherein the twisting machine comprises a central steering unit which is connected to all means for guiding and all means for twisting comprised in all twisting modules.

16. Twisting machine according to claim 14 or 15 wherein the central steering unit steers the tension and / or speed in all means for guiding and all means for wrapping.

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