EP4720392A1 - Device and method for producing an endless winding cable - Google Patents

Abstract

A device 100 produces an endless winding cable by winding a yarn around two thimbles 2, 4. The device comprises an guide 110, a carriage 112, a yarn feeder 114, and two thimble holders. The thimble holders are connected at a distance from each other. The carriage moves relative to the guide in a length direction. The yarn feeder is connected to the carriage and comprises a spool holder for holding a spool with the yarn, and an output guide for guiding the yarn to the cable during winding. The device comprises an elastic assembly 129 that provides a restoring force when it is deformed by an external force, which results from a tensile force exerted by the turns of the yarn. The elastic assembly is configured to allow the first thimble holder to move towards the second thimble holder against said restoring force, such that during winding the distance between the thimble holders decreases.

Description

Title: Device and method for producing an endless winding cable

The invention relates to a device for producing an endless winding cable according to the preamble of claim 1, as well as a method according to the preamble of claim 14.

A cable produced by a device or method of this type can be used in different types of industry, including but not limited to offshore, mining and heavy lifting and construction. In offshore, such a cable may be used as a mooring line for ships and structures like a floating oil exploration or production facility, or a floating wind turbine. In mining and heavy lifting such a cable may be used as a pendant for a crane. In construction these cables may be used as a tension member in a bridge or a roof.

A cable produced by a device of this type is known from WO-A1-2017/099589. This document discloses producing a cable by positioning two thimbles at a predetermined distance from each other and winding at least one yarn around the thimbles until a predetermined number of layers of yarn turns is provided at both thimbles. Notably, this document discloses adjusting the tension or length of the at least one yarn during winding. This adjustment of the tension during winding is achieved by controlling a yarn brake of the yarn feeder. Alternatively, an actuator moves the thimbles closer together during winding. The result is a cable wherein each layer of yarn has a predetermined amount of tension, with a higher tension in a subsequent layer of yarn than in a previous layer. This pre-tensioning of the yarn layers increases the break load of the resulting cable.

However, when relatively large pre-tensioning forces to the yarns are applied, the yarn brake and/or the yarn feeder may not be able to withstand such large forces. Moreover, the yarn tension needs to be controlled precisely, which may complicate production. For example, the sensors for measuring the yarn tension will need to be calibrated regularly which slows down production.

The invention aims to solve at least one of these problems, or at least to provide an alternative. In particular, the invention aims to provide an improved method, or at least an alternative method, for producing an endless winding cable wherein the yarn tension increases from the innermost layer of yarn to the outermost layer.

This aim is achieved by a device according to claim 1.

The device is designed for producing an endless winding cable by winding at least one yarn around two thimbles that are provided at opposite ends of the cable. The device comprises an elongated guide, a carriage, a yarn feeder, a first thimble holder, and a second thimble holder. The first thimble holder and the second thimble holder are connected to the elongated guide at a distance from one another, and are each designed to hold one of the two thimbles. The elongated guide and the carriage are movably connected to one another for a movement of the carriage relative to the elongated guide in a length direction of the elongated guide. The yarn feeder is connected to the carriage. The yarn feeder comprises at least one spool holder for holding a spool with the at least one yarn. The yarn feeder further comprises an output guide for guiding the at least one yarn to the cable during winding. The output guide and the first thimble holder, as well as the output guide and the second thimble holder, are movable relative to each other in at least a direction perpendicular to the length direction of the elongated guide for guiding the at least one yarn half a turn around respectively the first one of the two thimbles and the second one of the two thimbles during winding. The device comprises an elastic assembly that provides a restoring force when it is deformed upon application of an external force, which during winding results from a tensile force exerted by turns of the at least one yarn wound around the first and second thimble. The elastic assembly is configured to allow the first thimble holder to move towards the second thimble holder against the restoring force, such that during winding the distance between the first and second thimble holder decreases as more turns are wound.

In other words, as more turns of the at least one yarn are wound, the total tensile force they exert upon the thimbles increases. The total tensile force is at any moment during winding a total of the tension in all yarn turns already wound around the thimbles. This tension initially equals to the pre-tension which is applied to the yarn during winding. This pre-tension does decrease in each yarn turn as the distance between the thimbles reduces, but remains a minimum value due to the weight of the yarn itself. The net effect is that the total tensile force does increase as a result of the increasing number of yarn turns. This increasing tensile force results in an increase of the external force acting upon the elastic assembly. The external force exerted on the elastic assembly thus increases as more turns of yarn build up, deforms the elastic assembly and moves the thimbles closer together. By reducing the distance between the thimbles as more yarns are wound, the yarn tension in a subsequent layer of the at least one yarn is higher than the yarn tension in previous layers of the at least one yarn. For example, the decrease in distance between the thimbles per layer of yarn is in the range of 0.1 to 1 mm.

The elastic assembly resiliently deforms upon application of an external force, e.g. the elastic assembly is resiliently compressed or resiliently extended, and provides a restoring force that opposes the external force. By using an elastic assembly, the distance between the two thimbles is reduced automatically via mechanical means as more layers of yarn are wound around the thimbles. As the distance is adjusted via mechanical means, an electronic actuator for moving the thimbles is no longer required, and neither is a corresponding electronic controller. This simplifies the device or at least presents an alternative to control of the distance between the thimbles via an electronic actuator. Moreover, no sensors are required for measuring yarn tension for feedback to the controller. A calibration procedure for the sensors is thus avoided, therefore preventing downtime of the device and thus improving production. Furthermore, the yarn brake and/or the yarn feeder do not need to adjust the yarn tension, but rather can keep the tension constant during winding a new layer of yarn, which avoids applying too large forces to the yarn feeder and/or yarn brake.

Preferred embodiments are defined in the dependent claims and the following paragraphs.

In an embodiment, the elastic assembly comprises a spring or an elastic material. In a particular embodiment, the elastic assembly comprises a compression spring. An advantage of using a compression spring rather than an extension spring is that compression springs are less likely to fail. Extension springs are equipped with hooks or eyelets at their ends, which is a typical point of failure. Moreover, extension springs are more easily deformed beyond their elasticity limit, which results in plastic deformation, as compared to compression springs.

In an embodiment, the spring or the elastic material is detachably provided for adjusting a restoring force of the elastic assembly. In other words, the spring or the elastic material can be replaced by a spring or elastic material with different characteristics, e.g. a different spring constant or force-displacement curve.

In another embodiment, the elastic assembly comprises an adjustable spring for adjusting a restoring force of the elastic assembly. This obviates the need for fully replacing the spring or the elastic material, and the properties of the elastic assembly, e.g. a spring constant or forcedisplacement curve, can thus be adjusted more easily. For example, the elastic assembly comprises an adjustable gas spring.

An advantage of the two embodiments just described is that the properties of the elastic assembly can be selected on the basis of the desired length and thickness of the cable to be produced, the modulus of elasticity of the yarns to be used and the desired yarn tension gradient. On the basis of these variables, a required decrease in distance per layer of yarn can be calculated. This can be translated to a desired force-displacement curve for the elastic assembly. The elastic assembly is then selected or adjusted to match the desired force-displacement curve as closely as possible. In general, longer cables require a larger decrease in distance per layer of wound yarn. Stiffer cables require less decrease in distance per layer.

In an embodiment, the first thimble holder is provided on a frame, and the frame is movably connected to the elongated guide via the elastic assembly for movement of the first thimble holder relative to the elongated guide.

In a further embodiment, the elastic assembly comprises at least one spring oriented in the length direction of the elongated guide. In this manner, the restoring force provided by the at least one spring is aligned with the direction of the tensile force exerted by the wound yarn. In an alternative embodiment, the at least one spring is oriented at an angle to the direction of the elongated guide. In such embodiment, a component of the tensile force is still aligned with the restoring force.

In a further embodiment, the elastic assembly further comprises: at least one wheel for moving the frame with respect to the elongate guide, or at least one joint for rotating the frame with respect to the elongated guide. For example, a first part of the frame is connected to the elongated guide via the spring assembly and a second part of the frame is connected to the elongated guide via the wheel or joint.

In an embodiment, a frame is rigidly connected to the elongated guide and the first thimble holder is movably connected to the frame via the elastic assembly for movement of the first thimble holder relative to the elongated guide.

In an embodiment, the frame is detachably connected to the elongated guide, and is connectable to the elongated guide at a plurality of different positions along the elongated guide for setting the distance between the two thimbles. This enables producing cables of different lengths with the same device.

In an embodiment, the yarn feeder comprises tensioning means for maintaining a constant yarn tension in a part of the at least one yarn which is guided to the cable during winding.

The invention further relates to a method for producing an endless winding cable, according to claim 14. Such a method provides the same technical effects as described above in relation to the inventive device. Moreover, the preferred and/or optional features defined above for the device are preferred and/or optional features for the method.

The method comprises positioning a first thimble holder and a second thimble holder at a predetermined distance from one another. The distance corresponds to a required cable length. A first thimble is provided on the first thimble holder and a second thimble is provided on the second thimble holder. At least one yarn is provided. The method further comprises the step of winding the at least one yarn from the first thimble to the second thimble, a half turn around the second thimble, back to the first thimble, and a half turn around the first thimble. The step of winding is repeated until a predetermined number of layers of yarn turns is provided at both the first thimble and the second thimble, corresponding to a required cable thickness. An elastic assembly is provided, wherein the elastic assembly provides a restoring force when it is deformed upon application of an external force. During the step of winding, the first thimble holder is allowed to move towards the second thimble holder against the restoring force of the elastic assembly by the application of the external force, which external force results from a tensile force exerted by the turns of the at least one yarn wound around the first and the second thimble.

This method results in an endless winding cable with the same or similar technical effects as described above.

In an embodiment, the method comprises adjusting the restoring force of the elastic assembly. In a further embodiment, adjusting the restoring force of the elastic assembly comprises adjusting a spring force of an adjustable spring of the elastic assembly.

The invention, its effects, and advantages will be explained in more detail on the basis of the schematic drawing, in which:

Fig. 1 shows an end of a cable producible by the device and method of the invention;

Fig. 2 shows section ll-ll from fig. 4;

Fig. 3 shows a detail from fig. 2;

Fig. 4 shows a top view of the cable of fig. 1;

Fig. 5 shows section V-V from fig. 4;

Fig. 6 shows a perspective view of a device according to a first embodiment of the invention;

Fig. 7 shows a top view of the device of fig. 6;

Fig. 8 shows a side view of the device of fig. 6, without thimbles 2, 4;

Fig. 9 shows an end view of the device of fig. 6, without thimbles 2, 4;

Fig. 10 shows an end view of the device of fig. 6, seen from an end opposite to fig. 9;

Fig. 11 shows the device of fig. 6 in use;

Fig. 12 shows a perspective view of a device according to a second embodiment of the invention;

Fig. 13 shows a perspective view of a device according to a third embodiment of the invention; and

Fig. 14 shows a top view of the device of fig. 13.

The figures 1-5 show a cable producible by the device and method according to the invention, which is denoted in its entirety by reference number 1. The cable 1 has a first thimble 2 and a second thimble 4, and a plurality of yarns 6. The first 2 and the second 4 thimble are made of stainless steel and are provided at opposite ends of the cable 1. The plurality of yarns 6 are in this embodiment ten yarns 6 which all extend from the first to the second thimble, turn around the second thimble 4, extend from the second thimble 4 to the first thimble 2, and turn around the first thimble 2. In this manner each of the plurality of yarns 6 forms a semi-continuous loop around the first and second thimbles. This loop is repeated a plurality of times, in this embodiment 950 times. So each of the yarns 6 makes 950 turns, resulting in a total of 9500 turns of yarns 6. This will be explained in more detail later when describing the device and method according to the invention. The yarns 6 consist of fibres, in this embodiment aramid fibres with a density of 3220 dTex that are provided with a marine coating. This coating makes the fibres smoother which results in less fibre- to-fibre wear. These yarns are sold under the name Twaron® D2204 by Teijin Aramid.

Figure 2 shows that the thimble 2 holds a stack 9 with a plurality of layers 10 of yarn turns 6. This is shown in more detail in figure 3. In the upper part of figure 2 the stack 9 is shown in an exploded view for clarity. In reality, the stack 9 is held in the first thimble 2 as shown in the lower part of figure 2. The second thimble 4 holds layers of the same yarn turns 6 in the same manner and is therefore not shown in detail.

An inside 12 of the stack 9 is defined as a side of a first layer 13 of yarn turns 6 being closest to a centre 14 of the thimble 2. An outside 16 of the stack 9 is defined as a side of a last layer 15 of yarn turns 6 being farthest away from the centre 14 of the thimble 2. A stack height h is defined as the distance from the inside of the stack 12 to the outside of the stack 16. A previous layer 18 of turns of the at least one yarn 6 and a subsequent layer 20 of turns of the at least one yarn 6 are defined with respect to the centre 14 of the first thimble 2, in that the subsequent layer 20 of turns of the at least one yarn 6 is further away from the centre 14 of the respective thimble 2, than the previous layer 18 of turns of the at least one yarn 6.

A cable cover 28 extends around the cable 1 from the first thimble 2 to the second thimble 4, and bundles all yarn turns 6 extending between the first and the second thimble 2, 4 in one compact bundle 30 in a middle section 32 of the cable 1. In this embodiment, the cable cover 28 also covers the yarn turns 6 at the thimbles 2, 4.

The turns of the yarn 6 have a specific predetermined tension, which will be explained in more detail in below examples.

A device 100 according to a first embodiment of the invention is shown in figures 6-11. The device 100 is designed to produce an endless winding cable 1 by winding at least one yarn 6, in this embodiment ten yarns 6 simultaneously, around two thimbles 2, 4 that are provided at opposite ends of the cable 1. The device 100 comprises an elongated guide 110, a carriage 112, a yarn feeder 114, a first thimble holder 116 (figures 8-10), and a second thimble holder 118 (figures 8-10). In this embodiment the elongated guide 110 comprises two elongated l-prof iles 119. The elongated guide 110 is suspended from a ceiling of a production facility via supports (not shown) at an interval of approximately two meters. The yarn feeder 114 comprises in this embodiment ten spool holders 120, each designed for holding a spool 122. Each of the ten spools 122 holds a yarn. The yarn feeder 114 further comprises an output guide 124 for guiding all ten yarns to the cable 1 during winding (see fig. 11). The output guide 124 of this embodiment comprises rollers for guiding the ten yarns, and is in a fixed position relative to the yarn feeder 114. This fixed position is offset from a middle of the yarn feeder 114.

The yarn feeder 114 is connected to the carriage 112, in this embodiment via a pivot 125, which pivot is positioned at the middle of the yarn feeder 114. This enables the yarn feeder 114 to rotate about a vertical axis with respect to the carriage 112. This rotation results in the output guide 124 moving along an arc, in this case a semi-circle, with respect to the elongated guide 110 and thus relative to the first thimble holder 116 and to the second thimble holder 118. This semi-circle includes a movement in a direction perpendicular to the length direction of the elongated guide 110, and enables the output guide 124 to guide the ten yarns 6 half a turn around respectively the first thimble 2 at the first thimble holder 116 and the second thimble 4 at the second thimble holder 118 during winding when the output guide 124 is just beyond the respective one of the two thimbles 2, 4.

The yarn feeder 114 further comprises ten yarn brakes 126, each for one of the spools 122, for maintaining a constant yarn tension of the respective yarn 6 during winding. In this embodiment, the yarn brakes 126 are electro-mechanical brakes.

The first thimble holder 116 and the second thimble holder 118 are connected to the elongated guide 110 at a distance from each other, and are each designed to hold one of the two thimbles 2, 4. Figures 6 and 7 show the thimbles 2, 4 placed on the thimble holders 116, 118, whereas figures 8-10 show the thimble holders 116, 118 without thimbles. In the embodiment of figures 6-11, the first thimble holder 116 is provided on a first frame 128, that is connected to the elongated guide 110 via an elastic assembly 129. In this embodiment, the elastic assembly 129 comprises a compression spring, specifically a coil spring 130. One end of the spring 130 is connected to the first frame 128 and the other end is provided with a connector 131 for connecting to the elongated guide 110. First frame 128 is further provided with wheels 133 for movement along the elongated guide 110. Elastic assembly 129 and wheels 130 are provided at opposite ends of first frame 128. The second thimble holder 118 is provided on a second frame 132 that is connected to the elongated guide 110. In the embodiment, the second frame 132 is rigidly connected to the elongated guide 110, i.e. without an elastic assembly or wheels.

In this embodiment, both the first frame 128 and the second frame 132 are each detachably connected to the elongated guide 110 via a fastener. This fastener comprises in this embodiment a pin and a hole. The elongated guide 110 comprises the respective holes 136. The holes 136 have a mutual distance of 15 cm. The pins (not shown in the figures) are movably held in the respective frame 128, 132 for connecting the respective frame 128, 132 to the elongated guide 110 at a plurality of different positions along the elongated guide 110, which positions are defined by the holes 136. By retracting the pin, the respective frame 128, 132 is disconnected from the elongated guide 110 and can be moved along the elongated guide 110 for adjusting the distance between the two thimbles 2, 4. In the first frame 128, a movable pin is provided at the connector 131 of the elastic assembly 129. The pins are entered into one of the holes 136 when the respective frame 128, 132 is at a required position. This enables producing cables 1 of different lengths with the same device.

The carriage 112 is connected with the elongated guide 110 for a movement of the carriage 112 along the elongated guide 110 in a length direction of the elongated guide 110. The movable connection comprises in this embodiment wheels 140 that run inside the two elongated l-prof iles 119 of the elongated guide 110. The carriage 112 further comprises a carriage motor for moving the carriage along the elongated guide 110.

A method for producing an endless winding cable preferably uses a device according to the invention, such as device 100 described above. For the sake of clarity, the method will be described below in relation to this device. It should be noted however, that any other device or tools may be used within the scope of the invention, as longs as it operates according to a method within the scope of the attached method claims.

The method starts with positioning a first thimble 2 and a second thimble 4 at a predetermined distance from one another, which distance corresponds to a required cable length. Ten yarns 6 are provided on the spools 122, which are held on the spool holder 120 of the yarn feeder 114 as described above. The carriage 112 moves along the elongated guide 110. At the same time, the ten yarns 6 are wound off from the spools 122 with a constant yarn tension, using yarn brakes 126. The carriage 112 moves from the first thimble holder 116 to the second thimble holder 118, thus winding the ten yarns 6 from the first thimble 2 to the second thimble 4. When the carriage arrives at the second thimble holder 118, the spool holder 114 makes a half turn by rotating around pivot 125. This results in the spool guide 124 making a half turn around the second thimble 4, such that the ten yarns 6 make a first half turn around the second thimble 4. Then the carriage 112 moves back to the first thimble holder 116 so that the ten yarns 6 run back to the first thimble 2, where the spool holder 114 and thus the spool guide 124 make another half turn about pivot 125 such that the spool guide 124 lets the ten yarns 6 make a second half turn around the first thimble 2. These movements of the carriage 112 and spool holder 114 are repeated in case that the first and second thimbles 2, 4 are so wide that a multitude of ten yarn turns are provided next to each other in one layer. If only ten yarn turns are provided next to each other in one layer, then the device immediately proceeds to making a next layer.

Once a first layer of yarn turns is provided in both the first thimble and the second thimble 2, 4, the movements of the carriage 112 and spool holder 114 are repeated until the next layer of yarn turns is provided in the first and second thimble 2, 4. These steps are repeated until a predetermined number of layers of yarn turns is provided in both the first thimble 2 and the second thimble 4. This predetermined number of layers of yarn turns corresponds to a required cable thickness.

During winding, the already wound yarns 6 exert a tensile force on the thimbles 2, 4. This tensile force is directed along the length direction of the cable 1, which is parallel to the length direction of the elongated guide 110. The tensile force of the wound yarns 6 causes the spring 130 of the elastic assembly 129 to compress, thereby reducing the distance between the thimbles 2, 4. For example, the distance between the thimbles 2, 4 decreases by 0.1 mm per layer. Due to the reduced distance, the tension in the wound yarns 6 will decrease, such that the next turn of yarns 6 will have a higher tension than the previous turns of yarns. The total tensile force increases as more yarn turns are wound, and thus the spring 130 of the elastic assembly 129 is compressed more with each yarn turn. This results in a cable 1 of which the outer yarn layers have a higher tension than the inner yarn layers.

In order to finish the cable 1, a cable cover is provided around the turns of the yarn 6, such as the cable cover 28 which is shown in figs. 2 and 5. Such a cable cover bundles the turns of the yarn 6 into one compact bundle. Preferably, the same or another cover also covers the yarns which loop around the thimbles 2, 4.

Optionally, an adhesive is applied at the thimbles to mutually connect at least two of the layers of yarn. The adhesive is applied to the thimbles only, i.e. not to the yarns between the thimbles along the full length of the cable. Preferably, the adhesive is a resin, such as an epoxy resin.

Figure 12 shows a device 200 according to a different embodiment of the invention. The device 200 has many features in common with the device 100 of figures 6-11, and corresponding features have been given the same reference numeral increased by 100. In particular, elongated guide 210, carriage 212, spool holder 214 and l-profiles 219 of device 200 are the same as in device 100 of figures 6-11. Features that have not been given a reference number in figure 12 are also the same as in figures 6-11.

A difference of device 200 as compared to device 100 is that the elastic assembly 229 is provided at an angle to the length direction of the elongated guide 210. The elastic assembly 229 comprises a compression spring that is integrated in the first frame 228. Further, instead of a wheel, device 200 includes a joint 233 for rotation of the first frame 228 when the elastic assembly 229 is compressed due to the tensile force exerted on it during winding. This rotation moves the thimble holder of the first frame 228 closer to the thimble holder of the second frame 232 and thus decreases the distance between the thimbles as more yarn turns are wound around the thimbles.

A further alternative device 300 is shown in figures 13 and 14. Features that are common to device 300 and devices 100, 200 will not be discussed in detail, and the above description applies to such common features. Corresponding features have been given the same reference numeral as in figures 6-11, increased by 200.

In device 300, the first frame 328 is rigidly connected to the elongated guide 310. As described above in relation to device 100, the first frame 328 is detachably connected to the elongated guide 310 to place the thimble holders at a desired distance from each other at the start of the winding process. However, once attached to the elongated guide 310, the first frame 328 does not move in relation to the elongated guide 310. The first frame 328 comprises an elastic assembly 329 that enables movement of the first thimble holder 316 with respect to the first frame 328. As shown in fig. 14, the first thimble holder 316 extends from a slot 334 in the frame 328. The first thimble holder 316 is configured to move within the slot 334, in the length direction of the elongated guide 310. In particular, the first thimble holder 316 is configured to move towards the second thimble holder to decrease the distance between the thimbles during winding. The elastic assembly 329 comprises a rod 336 that is connected to the first thimble holder 316 and extends from the back of the first frame 328 (the side of the first frame that faces away from the second thimble holder). The elastic assembly 329 further comprises a plate 338 that is connected to the rod 336, with the plate 338 being movably connected to the first frame 328 via two compression springs 330. Thus, the first thimble holder 316, the rod 336 and the plate 338 are configured to move together relative to the first frame 328, wherein their movement in the direction towards the second thimble holder is against the spring force of compression springs 330. During winding the tensile force exerted by the wound yarn on the thimbles increases as more yarn is wound, which compresses the springs 330 and moves the first thimble holder 316 closer to the second thimble holder. The result is that subsequent layers of yarn have a higher tension than previous layers of yarn.

A first example is a cable made of yarns of aramid fibres with a density of 3220 dTex that are provided with a marine coating. These yarns are sold under the name Twaron® D2204 by Teijin Aramid. The length of the cable is 25 meters. The cable is made of a total of 9500 yarn turns, by winding 10 yarns at a time. There are 30 yarn turns in one layer, and 317 layers. A second example is a cable made of Twaron® D2204 yarns as well. The length of the cable is 29 meters. The cable is made by winding 10 yarns at a time. There are 10 yarn turns in one layer, and 350 layers.

A third example is a cable made of Twaron® D2204 yarns as well. The length of the cable is 45 meters. The cable is made of a total of 8800 yarn turns, by winding 10 yarns at a time. There are 30 yarn turns in one layer, and 293 layers.

A fourth example is a cable made of Dyneema® DM 20 yarns of 1760 dtex. Dyneema® is a trademark of DSM, the Netherlands. Dyneema fibres are made of Ultra-High Molecular Weight Polyethylene (UHMwPE), also known as high-modulus polyethylene (HMPE). The length of the cable is 29 meters. The cable is made of a total of 47870 yarn turns, by winding 10 yarns at a time. There are 100 yarn turns in one layer, and 479 layers.

A fifth example is a cable made of yarns of carbon fibres, in this case called filaments, made by Toho Tenax Europe GmbH. The product name is Tenax® UTS50 F24 24K 1600tex D. This yarn has 24000 filaments, which corresponds to a nominal linear density of 1600 tex. Tenax® is a trademark of Toho Tenax. The length of the cable is 12.5 meters. The cable is made of a total of 470 yarn turns, by winding 10 yarns at a time. There are 40 yarn turns in one layer, and 12 layers.

Variants of the shown embodiments of the device and method are well possible within the scope of the attached claims. It is possible to combine one or more features of one embodiment with one or more features of another embodiment. The features of the above described embodiments may be replaced by any other feature within the scope of the attached claims, such as the features described in the following paragraphs.

A cable according to the invention may be made of more or less than ten yarns, such as one yarn, two yarns, or at least five yarns. The total number of yarn turns, i.e. yarn turns per layer and number of layers, depends on the required strength of the cable, and the strength of one individual yarn, as well as the required safety margin. The number of yarn layers in the stack of layers is at least one, but is usually a plurality of layers. The number of layers depends on the required number of yarn turns, and the available width in the thimble resulting in a maximum number of yarn turns in the width direction.

Different types of yarns may be used, such as aramid yarns such as sold under the name Twaron (registered trademark of Teijin Aramid B.V.) and under the name Kevlar (registered trademark of E.L du Pont de Nemours and Company) with a density of 1610 dTex, 4830 dTex, 6440 dTex, 16100 dTex, or 17000 dTex, as well as higher, lower, and intermediate densities and with or without a coating. Instead of using aramid fibres, one could use other types of plastic fibres, such as para-copolyamide yarns, sold under the name Technora (registered trademark of Teijin Aramid B.V.), as well as yarns made of fibres with similar properties. It is further possible to use thermoplastic fibres, such as polyamide fibres, polyester fibres, polypropylene fibres, polyethylene fibres, HMPE fibres, LCAP fibres, or PBO fibres (Polybenzobisoxazole; sold under the name Zylon by TOYOBO CO., LTD), polyarylate fibres (sold under the name Vectran by Kuraray Co., Ltd). The cable could even comprise other types of yarns, e.g. yarns made of carbon fibres, a metal, or a natural fibre, such as basalt fibres. Yarns of fibres may consist for 100% of the relevant fibre type, but could also comprise a small portion of an auxiliary material, e.g. a coating on the fibres to protect the fibres against wear and/or environmental influences. As such auxiliary material is only a small portion in weight, and does not contribute to the strength of the cable, the phrase 'yarn consisting of fibres' is considered to include embodiments with such auxiliary materials within the context of this document.

The thimbles may be made of a plastic material instead of a metal, or of a different metal than stainless steel, including but not limited to different steel alloys, aluminium alloys, magnesium alloys, and titanium.

A device according to the invention has some of the components connected fixedly to each other, instead of connecting the different components of the device detachably and movably to each other as in the shown embodiment. By connecting fixedly one or both frames that comprises the thimble holders to the elongated guide, a simpler construction is possible. If one frame is connected fixedly, and the other detachably at different positions, it is still possible to produce cables of different lengths. If both frames are connected fixedly, cables of one length can be produced. It is further possible to connect the components in an indirect manner to each other, e.g. via the ground or another construction such as a wall or ceiling of a building. As an example, the thimble holders and/or their frames may be connected directly to a ceiling of a building, instead of via the elongated guide.

In an alternative embodiment, the carriage and the yarn feeder are connected to a fixed construction, while the elongated guide and both thimble holders and/or their frames are connected to each other and jointly movable with respect to the carriage and thus with respect to the yarn feeder too.

In a simple embodiment, the spool holder and the output guide may be integrated. The movement of the output guide relative to the first and second thimble holder may be implemented in alternative ways. The output guide may be movable with respect to the yarn feeder, in particular along a line at least partly perpendicular to the length direction of the elongated guide, instead of moving the whole yarn feeder relative to the carriage. In a further alternative embodiment, the first and second thimble holder are movable with respect to the elongated guide, and thus the output guide, perpendicular to the length direction of the elongated guide.

In an embodiment, the elongated guide comprises one member, or more than two members. In an alternative embodiment, the elongated guide comprises T-shaped members. In an embodiment, the elongated guide comprises a rack which cooperates with a pinion for driving the carriage. In an embodiment, the movable connection between the carriage and the elongated guide comprises a linear slide.

The optional yarn brake may either engage on the spool, or directly on the yarn. In an embodiment, the yarn brake is integrated with the output guide. In an embodiment, the yarn brake is a hydraulically controlled brake.

The elastic assembly provides a restoring force that may be linearly or non-linearly related to the amount of deformation, e.g. by compression or extension. Alternatively, the elastic assembly may be linear over a first range of deformation and non-linear over a second range of deformation.

The embodiments of the figures show a coil spring. Alternatively or additionally a different type of spring can be used, such as a leaf spring, a volute spring or a gas spring.

Examples of elastic materials may include natural or synthetic rubber, such as polybutadiene, or elastic polymers, such as elastomers.

In an embodiment, the elongate guide comprises the elastic assembly which is constructed to resiliently compress. In a first embodiment, the elongated guide comprises a telescopic construction for adjusting the length of the elongated guide, with the elastic assembly arranged to oppose a length reduction. For example, the telescopic construction comprises a hollow beam and a second beam that extends in the hollow beam, with the second beam being movable with respect to the hollow beam. In this embodiment, the thimble holders may be rigidly connected to the elongated guide. During winding, the tensile force exerted by the wound yarn will work against the restoring force of the elastic assembly to contract the telescopic construction and thereby reduce the distance between the two thimble holders. In a second embodiment, the elongated guide comprises a material or shape that resiliently compresses under application of an external force in the length direction of the elongated guide.

As described above, the first thimble holder is configured to move towards the second thimble holder. In other words, at least one of the thimble holders is configured to move towards the other thimble holder. In an embodiment, both thimble holders are configured to move towards the respective other thimble holder. Optionally, a sensor is provided for measuring the yarn tension of the yarn guided to the cable during winding. Optionally, a sensor is provided for measuring the distance between the thimble holders.

In each of the embodiments of the figures, the elastic assembly comprises two springs. Alternatively, a different number of springs is provided, e.g. 1, 4 or 6 springs. For example, the device 100 may comprise 2 more springs 130 instead of the wheels 133.

Preferably, the cable is made by winding multiple yarns at a time and a single turn of yarn forms a layer of yarn turns. For example, 40 yarns are wound at a time and each layer comprises 40 yarns. Alternatively, a layer can comprise multiple yarn turns. In such case, also within a layer of yarn turns a gradient in the yarn tension may exist, in addition to the gradient in yarn tension from the innermost layer to the outermost layer. This is acceptable. As long as the outermost layer are provided with a higher yarn tension than the innermost layers, the break load of the resulting cable is increased as compared to a cable produced with constant yarn tension.

It is noted that British spelling is applied in the above specification for terms such as 'fibre' and 'centre'. These terms can be replaced for the relevant US type of spelling, 'fiber' and 'center' without changing the content of this specification.

Claims

1. Device (100, 200, 300) for producing an endless winding cable (1) by winding at least one yarn (6) around two thimbles (2, 4) that are provided at opposite ends of the cable (1), comprising an elongated guide (110, 210, 310), a carriage (112, 212, 312), a yarn feeder (114, 214, 314), a first thimble holder (116, 316), and a second thimble holder (118), wherein the first thimble holder (116, 316) and the second thimble holder (118) are connected to the elongated guide (110, 210, 310) at a distance from one another, and are each designed to hold one of the two thimbles (2, 4), the elongated guide (110, 210, 310) and the carriage (112, 212, 312) are movably connected to one another for a movement of the carriage (112, 212, 312) relative to the elongated guide (110, 210, 310) in a length direction of the elongated guide (110, 210, 310), the yarn feeder (114, 214, 314) is connected to the carriage (112, 212, 312), and comprises at least one spool holder (120) for holding a spool (122) with the at least one yarn (6), and an output guide (124) for guiding the at least one yarn (6) to the cable during winding, the output guide (124) and the first thimble holder (116, 316), as well as the output guide (124) and the second thimble holder (118), are movable relative to each other in at least a direction perpendicular to the length direction of the elongated guide (110, 210, 310) for guiding the at least one yarn (6) half a turn around respectively the first one of the two thimbles (2) and the second one of the two thimbles (4) during winding, characterised in that: the device comprises an elastic assembly (129, 229, 329) that provides a restoring force when it is deformed upon application of an external force, which during winding results from a tensile force exerted by turns of the at least one yarn (6) wound around the first (2) and second (4) thimble, and the elastic assembly (129, 229, 329) is configured to allow the first thimble holder (116, 316) to move towards the second thimble holder (118) against the restoring force, such that during winding the distance between the first (116, 316) and second (118) thimble holder decreases as more turns are wound .

2. Device (100, 200, 300) according to claim 1, wherein the elastic assembly (129, 229, 329) comprises a spring (130, 330) or an elastic material.

3. Device (100, 200, 300) according to claim 2, wherein the elastic assembly (129, 229, 329) comprises a compression spring (130, 330).

4. Device (100, 200, 300) according to claim 2 or 3, wherein the spring (130, 330) or the elastic material is detachably provided for adjusting a restoring force of the elastic assembly (129, 229, 329).

5. Device (100, 200, 300) according to claim 2 or 3, wherein the elastic assembly (129, 229, 329) comprises an adjustable spring for adjusting a restoring force of the elastic assembly.

6. Device (100, 200) according to any one more of claims 1-5, wherein the first thimble holder (116, 316) is provided on a frame (128, 228, 328), and the frame (128, 228, 328) is movably connected to the elongated guide (110, 210, 310) via the elastic assembly (129, 229, 329) for movement of the first thimble holder (116, 316) relative to the elongated guide (110, 210, 310).

7. Device (100) according to claim 6, wherein the elastic assembly (129) comprises at least one spring (130) oriented in the length direction of the elongated guide (110).

8. Device (200) according to claim 6, wherein the elastic assembly (229) comprises at least one spring oriented at an angle to the direction of the elongated guide (220).

9. Device (100, 200) according to claim 7 or 8, wherein the elastic assembly (129, 229) further comprises at least one wheel (133) for moving the frame with respect to the elongate guide (110, 210).

10. Device (200) according to claim 8, wherein the elastic assembly (229) further comprises at least one joint (233) for rotating the frame (228) with respect to the elongated guide (210).

11. Device (300) according to any one or more of claims 1-5, wherein a frame (328) is rigidly connected to the elongated guide (310) and the first thimble holder (316) is movably connected to the frame (328) via the elastic assembly (329) for movement of the first thimble holder (316) relative to the elongated guide (310).

12. Device (100, 200, 300) according to any one or more of claims 6-11, wherein the frame (128, 228, 328) is detachably connected to the elongated guide (110, 210, 310), and is connectable to the elongated guide (110, 210, 310) at a plurality of different positions along the elongated guide (110, 210, 310) for setting the distance between the two thimbles (2, 4).

13. Device (100, 200, 300) according to any one or more of the previous claims, wherein the yarn feeder (112, 212, 312) comprises tensioning means (126) for maintaining a constant yarn tension in a part of the at least one yarn (6) which is guided to the cable (1) during winding.

14. Method for producing an endless winding cable (1), comprising the steps of: positioning a first thimble holder (116, 316) and a second thimble holder (118) at a predetermined distance from one another, which distance corresponds to a required cable length, providing a first thimble (2) on the first thimble holder (116, 316) and a second thimble (4) on the second thimble holder (118); providing at least one yarn (6), a step of winding the at least one yarn (6) from the first thimble (2) to the second thimble (4), a half turn around the second thimble (4), back to the first thimble (2), and a half turn around the first thimble (2), repeating the step of winding, until a predetermined number of layers of yarn turns is provided at both the first thimble (2) and the second thimble (4), corresponding to a required cable thickness, characterised by: a step of providing an elastic assembly (129, 229, 329) that provides a restoring force when it is deformed upon application of an external force; and during the step of winding, allowing the first thimble holder (116, 316) to move towards the second thimble holder (118) against the restoring force of the elastic assembly (129, 229, 329) by the application of the external force, which external force results from a tensile force exerted by the turns of the at least one yarn (6) wound around the first (2) and the second (4) thimble.

15. Method according to claim 14, comprising adjusting the restoring force of the elastic assembly (129, 229, 329).

16. Method according to claim 15, wherein adjusting the restoring force of the elastic assembly (129, 229, 329) comprises adjusting a spring force of an adjustable spring of the elastic assembly.