System for anchoring a cable

Abstract

The present invention relates to a system for anchoring a cable (3), comprising: - a frame (2); - a drum (1) rotatably mounted on the frame about an axis of rotation (X), the drum having a lateral surface (S) about an axis (Y) parallel to the axis of rotation (X), the drum being adapted to allow the cable to run by winding and / or unwinding the cable along a portion of the lateral surface in response to a variation of the mechanical tension of the cable about the axis of rotation (X); - at least one torsion spring (10a, 10b, 10c, 10d) arranged between the drum and the frame so as to compensate for variations of the tension of the cable.

Description

Technical Field

[0001] The present invention relates to a cable anchoring system, a lifting device including such an anchoring system, and a lift including said anchoring system. Background Technology

[0002] The lifting and handling of containers can be achieved using spreader arms, which are connected by ropes to a Ship to Shore (STS) type crane for unloading containers from or loading them onto a ship. A motor mounted on the crane is used to raise or lower the spreader arm via the ropes. Additionally, fastening members (often called "torsion locks") are attached to the spreader arm. Opening or closing the fastening members allows for the attachment or release of containers. To enable the opening or closing of the fastening members, they are typically powered by a hydraulic unit, most commonly located on the spreader arm. Furthermore, the hydraulic unit can be adapted to force the spreader arm to extend or retract during use, making it suitable for lifting containers of different sizes. The hydraulic unit is advantageously powered from the crane via cables: the first end of the cable is wound on a winding machine mounted on the crane, and the second end of the cable is advantageously connected to the spreader arm via a frame (often called a "head trolley") below which the spreader arm is mounted. Alternatively, the fastening members can be entirely electric, and their power supply from the crane is also provided via such cables. The cable may further include a data bus, such as a Controller Area Network (CAN) bus, responsible for transmitting locking or unlocking information along with any other information items required to control the crane (weighing, lighting, etc.) to the fastening components.

[0003] To avoid damaging the cable, the unwinding and winding of the cable on the winding machine must ensure that the cable remains taut throughout all operations such as lifting, unloading, and loading of the container. The unwinding and winding of the cable on the winding machine to follow the movement of the spreader is typically handled automatically by driving the winding machine according to a theoretical model that calculates the torque applied to the winding machine based on the stage of operation and the crane's position on its tracks.

[0004] However, since the movement of the spreader is usually managed manually by the crane operator, some of the spreader's movement cannot be immediately compensated for by the winding machine. This is especially true in cases where the spreader moves suddenly when the frame is subjected to impact, such as if the container misses the hatch and strikes the guide of the container ship.

[0005] Therefore, the cable anchoring system is mounted on a frame on which the spreader is installed below. This anchoring system may include a cylindrical drum advantageously rotatably mounted relative to the frame via bearings (e.g., ball bearings). Under cable tension, such as in the event of a sudden movement of the spreader, the drum is configured to rotate about its axis of rotation. The rotational movement of the drum causes the cable to wind and / or unwind around the drum, thereby allowing the cable to travel a specific amount of distance.

[0006] The anchoring system may further include compression springs coupled to one or more dampers (e.g., hydraulic, metallic, or elastic (tensioner) dampers) adapted to dampen cable travel. More specifically, when the winding machine pulls or pushes the cable and the drum is set to rotate, the compression springs exert a restoring force on the drum under the action of the drum rotation, proportional to the elongation of the compression springs, and the dampers absorb shocks.

[0007] However, this anchoring system (whose volume is limited by the size of the frame housing them) does not allow for sufficient cable travel, especially under impact. Specifically, when the winding machine pulls the cable, the cable travel allowed by the anchoring system in the unwinding direction is typically about 40 mm, and when the winding machine releases the tension on the cable, the cable travel allowed by the anchoring system in the winding direction is typically about 40 mm. This leads to rapid cable wear, requiring frequent and costly maintenance.

[0008] Furthermore, compression springs are subjected to high stress, resulting in a short lifespan, potentially less than a year if the spring were used at a rate of approximately 2000 hours per year. Therefore, changes to the anchoring system or replacement of the spring are necessary. The bearings also have a shorter lifespan than expected.

[0009] In addition, the compression springs and / or other damping devices that may be included in the anchoring system can be bulky. Summary of the Invention

[0010] The object of the present invention is to design a cable anchoring system, which is preferably suitable for installation on the frame of a crane intended to support a lifting device, thereby allowing for a greater cable travel distance compared to previously described anchoring systems, while maintaining a small size and ease of manufacture.

[0011] Therefore, the present invention provides a cable anchoring system, comprising: -frame, - A reel, rotatably mounted on a frame about a rotation axis, the reel having a side surface about an axis parallel to the rotation axis, the reel rotating about the rotation axis in response to changes in cable tension, the reel being adapted to allow cable travel by winding and / or unwinding the cable along a portion of the side surface.

[0012] - At least one torsion spring is arranged between the drum and the frame to compensate for changes in cable tension.

[0013] Under the rotational motion of the drum around its axis of rotation, a torsion spring generates a torsional angle around the axis of rotation to compensate for changes in cable tension. Conversely, a compression spring elongates, and to compensate for changes in cable tension, it must be supplemented with a yoke and / or pivot connector. Furthermore, torsion springs have a small volume, and increasing the allowable travel of the cable by winding and / or unwinding the cable around its side surface is equivalent to increasing the angular offset between the torsional angles at the ends of the torsion spring, causing little or no additional volume or difficulty in manufacturing the torsion spring. Conversely, increasing the allowable travel of the cable with a compression spring is equivalent to increasing the length of the compression spring, and thus its volume, and / or bringing the compression spring closer to the axis of rotation, meaning the compression spring must be able to withstand much greater forces. Such compression springs are difficult to manufacture. Therefore, anchoring systems incorporating torsion springs are easier to manufacture, more adaptable, and smaller in size.

[0014] Other optional but advantageous features, considered individually or in combination: - At least one torsion spring includes a first portion mounted on a frame and a second portion mounted on a drum, the second portion being adapted to pivot relative to the first portion; - The cable anchoring system includes at least two torsion springs arranged in series; - The first part of the first spring is mounted on the frame, the first part of the second spring is mounted on the drum, and the second part of the first spring is rigidly connected to the second part of the second spring; - Each torsion spring includes a rigid and hollow outer shaft, a rigid central shaft housed inside the rigid and hollow outer shaft, and a damper configured to dampen the torsional motion of the rigid and hollow outer shaft relative to the rigid central shaft; - The damper of a torsion spring includes a plurality of elastomeric elements arranged between a rigid central shaft and a rigid, hollow outer shaft; - Each torsion spring includes a first metal hollow square-base prism forming a rigid and hollow outer shaft, a second prism forming a central shaft, the second prism being arranged in the first prism with an angular offset relative to the first prism, and each elastomeric element being a cylinder arranged at each corner of the first prism between the first prism and the second prism. - The anchoring system includes two torsion springs connected in series, with the second base prism of the first torsion spring connected to the second base prism of the second torsion spring; - At least one torsion spring is configured to dampen the force generated by the rotation of the drum about a rotation axis between a first stop position and a second stop position of the drum, the first stop position and the second stop position being angularly offset from the rotation axis by an angle between 0° and 90°, preferably between 0° and 60°. - The anchoring system includes at least two sets of torsion springs arranged in parallel, with the first part of each set of torsion springs mounted on the frame and the second part of each set of torsion springs mounted on the drum; - The anchoring system further includes a compression spring and / or a tension spring, the compression spring and / or tension spring comprising a first portion mounted on the frame and a second portion mounted on the drum.

[0015] Another subject of the present invention relates to a lifting device, comprising: - A lifting device, comprising at least one fastening member for securing the load to be lifted. - As described above, the cable anchoring system includes a frame and a reel, the frame being attached to a lifting device and the reel being attached to the frame. - A winding machine, suitable for attachment to an elevator. - A cable, the first end of which is anchored to the drum of the anchoring system by being fixedly wound around the side surface of the drum at least two times, and the second end of which is wound on a winding machine.

[0016] Another subject of the invention relates to a lift, such as a crane, gantry crane, or forklift, which includes the lifting device as described above. Attached Figure Description

[0017] Other features and advantages of the invention will become apparent from the following detailed description with reference to the accompanying drawings, in which: - Figure 1A , Figure 1B and Figure 1C An example of the application of the cable anchoring system according to the invention is shown, wherein the system is attached to a lifting device that is itself mounted on a crane; - Figure 2A , Figure 2B and Figure 2CA specific embodiment of the cable anchoring system according to the invention is shown, wherein the side surface of the drum has a circular shape, and the axis of rotation of the drum relative to the frame passes through the center of the circle: Figure 2A The neutral position of the reel is shown. Figure 2B This illustrates a scenario where under-tension is applied to a cable on a spool, causing the spool to rotate in the cable's winding direction. Figure 2C This illustrates a scenario where a cable is subjected to excessive tension on a spool, causing the spool to rotate in the cable's unfolding direction; - Figure 3A , Figure 3B and Figure 3C A specific embodiment of the cable anchoring system according to the invention is shown, wherein the side surface of the drum has a circular shape, and the axis of rotation of the drum relative to the frame is offset relative to the center of the circle: Figure 3A The neutral position of the reel is shown. Figure 3B This illustrates a scenario where under-tension is applied to a cable on a spool, causing the spool to rotate in the cable's winding direction. Figure 3C This illustrates a scenario where a cable is subjected to excessive tension on a spool, causing the spool to rotate in the cable's unfolding direction; - Figure 4A , Figure 4B and Figure 4C A specific embodiment of the cable anchoring system according to the invention is shown, wherein the side surface of the drum has an elliptical shape, and the axis of rotation of the drum relative to the frame is offset relative to the center of the ellipse: Figure 4A The neutral position of the reel is shown. Figure 4B This illustrates a scenario where under-tension is applied to a cable on a spool, causing the spool to rotate in the cable's winding direction. Figure 4C This illustrates a scenario where a cable is subjected to excessive tension on a spool, causing the spool to rotate in the cable's unfolding direction; - Figure 5 A cable anchoring system is shown, wherein the system includes a drum and a compression spring, the drum having an elliptical shape and a rotation axis offset relative to the center of the ellipse, the compression spring being adapted to dampen the travel of the cable by winding and / or unwinding the cable around a portion of the ellipse; - Figure 6 A specific embodiment of a torsion spring is shown, the torsion spring comprising a first metal and hollow square-based prism, a second metal and hollow square-based prism housed within the first prism at an angular offset relative to the first prism, and four elastomeric cylinders arranged at the corners of the first prism between the first prism and the second prism. -Figure 7A, Figure 7B , Figure 7C and Figure 7DA specific embodiment of the anchoring system of the present invention is shown, wherein the system includes a drum and two sets of torsion springs, the drum having an elliptical shape and a rotation axis offset relative to the center of the ellipse, the two sets of torsion springs being adapted to dampen cable travel by winding and / or unwinding the cable around a portion of the ellipse, and the two sets of torsion springs being arranged along the rotation axis of the drum to allow the drum to rotate relative to a frame, each set of torsion springs comprising two torsion springs mounted in series. Figure 7B The neutral position of the reel is shown. Figure 7C This illustrates a scenario where under-tension is applied to a cable on a spool, causing the spool to rotate in the cable's winding direction. Figure 7D This illustrates a scenario where a cable is subjected to excessive tension on a spool, causing the spool to rotate in the cable's unfolding direction; - Figure 8 A specific embodiment of the anchoring system according to the invention is shown, wherein at least one torsion spring is a metal spring, and the anchoring system further includes a shaft and bearings configured to guide the rotation of the drum about its axis of rotation relative to the frame.

[0018] For readability reasons, the accompanying drawings are not necessarily drawn to scale. Detailed Implementation

[0019] The present invention relates to a cable anchoring system comprising a frame and a reel, the reel being adapted to be mounted on the frame and used to anchor a cable to the frame.

[0020] refer to Figure 1A , Figure 1B and Figure 1C The frame 2 is preferably a frame adapted for mounting on a spreader 4, which includes one or more fastening members 5 adapted to pick up loads. The fastening members 5 of the spreader 4 may, for example, include four twist locks adapted to clamp a container. In use, the spreader 4 is connected to an elevator 6, such as a crane, via a lifting device 7 adapted to allow the spreader 4 to move relative to the elevator 6, typically by raising or lowering the spreader 4. This movement can be remotely controlled by an operator, such as a crane operator located in a cab or cab, who alternately controls several cranes from the cab or cab. Alternatively, the movement can be managed fully automatically without operator intervention. The lifting device 7 of the spreader 4 may include ropes and one or more motors mounted on the elevator 6.

[0021] according to Figure 1A , Figure 1B and Figure 1CIn an embodiment not shown, the second spreader can be connected to the elevator 6 via its lifting device, the elevator 6 further including an intermediate platform. This configuration is particularly advantageous when the elevator is an STS crane: the spreader 4 is used to move containers between the ship and the platform, while the second spreader is used to move the containers between the platform and the dock.

[0022] Cable 3 includes one or more conductive links for power and / or data transmission. Each conductive link may be in the form of a conductive wire, optical fiber, or any other suitable form. Preferably, the cable includes at least a conductive link for supplying power and a conductive link for controlling the fastening member 5 of the lifting device 4. When the reel 1 is in use, i.e., when the reel 1 is mounted on the frame 2, the frame 2 is mounted on the lifting device 4, and the lifting device 4 is connected to the elevator 6, the first end of the cable is anchored to the frame 2 via the reel 1, and the second end of the cable 3 is wound onto a winding machine mounted on the elevator 6. More specifically, the reel according to the invention includes a side surface (S) positioned about an axis (Y), such that when the reel 1 is in use, the first end of the cable 3 is wound onto said side surface (S).

[0023] The winding machine installed on the lifting platform is typically an electrically controlled winding machine that includes a motor that winds or unwinds the cable to maintain cable tension regardless of the operating phase of the lifting device (e.g., during ascent, descent, motion setting, or stop). A control unit calculates a torque setpoint to be applied based on the operating phase. The torque value must be high enough to maintain cable tension without damaging the cable. The torque setpoint is sent to a frequency converter, which converts the torque setpoint into a current to be applied to the motor. For example, a change in the torque setpoint causes a change in the motor current when the lifting device position changes or the operating phase changes. This control loop has a non-zero response time, which is the sum of at least the response time associated with the electronics and the response time associated with the conversion of the current setpoint. The response time associated with the electronics is estimated to be approximately 75 ms. This response time may not allow the winding machine to respond quickly enough in certain situations, such as in the event of sudden movement of the lifting device, or, for example, in the event of an impact or gust of wind, thus creating tension in the cable.

[0024] Therefore, the spool 1 is adapted to be rotatably mounted on the frame 2 about a rotation axis (X) parallel to the axis (Y), such that when the spool 1 is in use, the spool 1 can rotate freely about the rotation axis (X) under the tension in the cable 3 that is not immediately compensated by the winding machine, thereby allowing the cable 3 to travel by winding and / or unwinding the cable along a portion of the side surface (S) around the side surface (S).

[0025] More precisely, due to the torque applied to the cable by the winding machine, the drum in the neutral position can withstand tension from the cable, thereby keeping the cable taut. The mechanical tension of the cable is understood as the change in the tension applied to the drum by the cable relative to the tension applied to the drum in the neutral position. It can be under-tension (corresponding to a slack cable configuration) or over-tension (a configuration where the winding machine pulls the cable with a tension greater than the theoretical value generated by the set point). This mechanical tension will cause the drum to rotate about the axis of rotation (X) relative to this neutral position. In the case of under-tension, the rotational movement about the axis of rotation (X) will be completed in the winding direction to pick up the slack cable until optionally reaching a first stop position. In the case of over-tension, the rotational movement about the axis of rotation (X) will occur in the unwinding direction to release the cable until optionally reaching a second stop position.

[0026] By way of example, the first stop position and the second stop position are offset at an angle between 0° and 60° relative to the axis of rotation (X), preferably between 0° and 90°.

[0027] The side surface (S) of the roll in a plane (P) perpendicular to the axis of rotation (X) may have a circular shape. Alternatively, the side surface (S) in the plane (P) may have an oval or elliptical shape, or any other shape with a non-constant radius of curvature.

[0028] The axis of rotation (X) may intersect the plane (P) at the center of a circle, the radius of which is equal to the radius of curvature of a portion of the side surface and the circle is tangent to the portion along which the cable is wound and / or unwound. For example, if the side surface has a circular shape in the plane (P), the axis of rotation (X) may intersect the plane (P) at the center of the side surface.

[0029] Alternatively, the axis of rotation (X) can intersect the plane (P) at any other point in the plane (P).

[0030] Figure 2A , Figure 2B and Figure 2C A specific example of a reel used on a frame is shown, wherein the reel has a circular shape in a plane (P), and the axis of rotation (X) intersects the plane (P) at the center of the circle. Specifically, Figure 2A The configuration of the reel in a neutral position is shown. Figure 2B The scenario of understrength cable is illustrated: the spool rotates from the neutral position about the axis of rotation (X) in the winding direction of the cable to wind up the slack cable. Figure 2CThe scenario of cable over-tension is illustrated: the spool rotates from a neutral position about the axis of rotation (X) in the cable unfolding direction to unfold the cable.

[0031] Figure 3A , Figure 3B and Figure 3C Another specific example of a reel used on a frame is shown, wherein the reel still has a circular shape in the plane (P), but the axis of rotation (X) does not intersect the plane (P) at the center of the circle. In particular, Figure 3A The configuration of the reel in a neutral position is shown. Figure 3B This illustrates a scenario where the cable is under-tensioned. Figure 3C This illustrates a scenario of excessive tension on a cable.

[0032] Still using examples, Figure 4A , Figure 4B and Figure 4C The diagram illustrates a case where the reel has an elliptical shape in a plane (P) and the axis of rotation (X) intersects the plane (P) at the center of a circle instead of at the center of the ellipse, the radius of which is equal to the bending radius of a portion of the side surface (S) of the cable being wound and / or unwound, and the circle is tangent to that portion. Figure 4A The neutral position of the reel is shown. Figure 4B This illustrates a scenario of under-tension in the cable. Figure 4C This illustrates a scenario of excessive tension on a cable.

[0033] Preferably, the spool is arranged such that during use of the spool, a first portion of the first end of the cable remains wound around the surface (S) throughout all stages of use of the frame, and due to the rotational movement of the spool about the axis of rotation (X) between a first stop position and a second stop position, a second portion of the cable in the extension of the first portion is wound and / or unwound along a portion of the side surface (S). By way of example, the length of the first portion of the first end of the cable is at least equal to two full turns of the surface (S), preferably more than two and a half turns. The first portion of the first end is advantageously long enough to counteract the tension of the cable at the end of the cable by a so-called winch effect. In a manner known per se, the winch effect establishes a ratio between the holding force applied to one end of the cable wound around the side surface of a cone, such as a cone with a circular cross-section or a cone with a non-circular cross-section (e.g., an elliptical cross-section), the load force depending on the coefficient of friction of the cable on the side surface of the cone.

[0034] The anchoring system according to the invention further includes at least one torsion spring disposed between the drum and the frame. When a sudden tension in the cable on the drum drives the drum to rotate about the axis of rotation (X) in the winding or unwinding direction of the cable (wherein the sudden tension in the cable is understood as a change in mechanical tension relative to the equilibrium tension, which allows the cable to be kept taut), the torsion spring is configured to generate a return force on the drum that tends to compensate for the tension change. Thus, by means of the drum, the torsion spring allows tension in the cable to be limited and the cable to be kept taut, thereby preventing damage to the cable. Preferably, the torsion spring or a set of torsion springs generates all the return force on the drum. Alternatively, the anchoring system may further include a compression spring and / or a tension spring, such that the compression spring and / or the tension spring generates at least a portion of the return force on the drum.

[0035] More precisely, under the mechanical tension of the cable and the resulting rotation of the drum about the axis of rotation (X), each torsion spring deforms, generating a torsion angle and thus a return force proportional to the torsion angle on the drum, which tends to counteract the torsion angle and bring the drum back to its initial position. In the cable winding direction, the torsion spring can deform until it reaches a first limit torsion angle. In the cable unwinding direction, the torsion spring can deform until it reaches a second limit torsion angle. In a variation, the first and second limit torsion angles correspond to a first and second stopping position of the drum's rotation about the axis of rotation (X), respectively. In other words, when the torsion spring has reached the first limit torsion angle, the rotation of the drum about the axis of rotation (X) is locked in one direction by the torsion spring, and when the torsion spring has reached the second limit torsion angle, the rotation of the drum is locked in the other direction. In a preferred variation, the first and second stopping positions are reached slightly earlier than the torsion springs reach their first and second limit torsion angles by the rotation of the drum about the axis of rotation (X). This implementation advantageously prevents the torsion spring from wearing out too quickly. In practice, the first and second stop positions can be fixed by external mechanical stops, such as progressive rubber stops known to those skilled in the art, which dampen the impact when the drum reaches its stop position. Typically, the first or respective second stop positions and the first or respective second limit torsion angles are offset by approximately 4°.

[0036] The arrangement of the torsion springs between the drum and the frame can be implemented such that each torsion spring is in the middle of its deformation range when the drum is in the neutral position. This allows for equal travel in both the winding and unwinding directions of the cable.

[0037] By way of example, if the first and second stop positions are offset by an angle of 90° relative to the axis of rotation (X), then the midpoint of the deformation range of each torsion spring is preferably associated with a position at 45° on the drum. Again by way of example, if the first and second stop positions are offset by an angle of 60° relative to the axis of rotation (X), then the midpoint of the deformation range of each torsion spring is preferably associated with a position at 30° on the drum.

[0038] Torsion springs have an advantage over conventionally used compression springs (see...). Figure 5 The compression spring 8 (comprising a first portion attached to the frame and a second portion attached to the drum) has a smaller volume, particularly when the torsion spring is arranged along the axis of rotation (X). Specifically, the compression spring has a limited elongation or compression length: increasing the cable length required necessitates increasing the length of the compression spring at a fixed distance from the axis of rotation (X), thus increasing the volume of the spring, or it requires placing the spring closer to the axis of rotation (X). However, in the latter case, the compression spring must be able to withstand very large forces to counteract the cable forces. Specifically, the cable tension along the cable axis can be approximately 2000 N, and the tension on the spring may be even greater, or even stronger, when the spring is placed closer to the axis of rotation. To withstand such forces, the compression spring must therefore have a greater wire thickness, which also significantly increases its length and thus its volume, but also raises questions about the manufacturability of the compression spring.

[0039] Furthermore, as with any spring, a compression spring must preferably be used in its linear region without reaching its stopping position to avoid excessively reducing the life of the spring, which necessitates further increasing the length of the compression spring.

[0040] By way of example, consider a conventional anchoring system comprising a compression spring with a free length of 240 mm and an elongation of 86 mm. The compression spring is positioned such that it must pivot slightly at each end to follow the movement of the drum, but the ratio of spring travel to cable travel remains approximately 1:1. Therefore, this cable anchoring system allows for approximately 86 mm of cable travel. To increase the cable travel to 630 mm without changing the position of the compression spring, it would be suggested to replace the 240 mm compression spring with a spring of (240 × 630) / 86 mm (i.e., approximately 1.9 m).

[0041] Alternatively, if it is desired to maintain an actual spring length of 240mm while allowing for a cable travel of 630mm, the compression spring would have to be positioned approximately 7 to 8 times closer to the axis of rotation, which would proportionally increase the force borne by the compression spring significantly. In this configuration, the compression spring would necessarily have a much larger wire diameter, and thus, the spring length could ultimately be longer than the desired 240mm. Compression springs with these characteristics are either impossible to manufacture or extremely difficult to manufacture. Furthermore, the dimensions of all attachments to the compression spring subjected to these considerable forces would also have to be designed to withstand such considerable forces, which would significantly increase the cost of the entire anchoring system. Finally, the risk of failure for such an anchoring system would be very high.

[0042] The force exerted by the torsion spring directly generates the rotation angle; increasing the allowable cable travel is equivalent to increasing this rotation angle, which has no impact on volume. Furthermore, the torsion spring can be easily arranged inside the drum along the axis of rotation (X), resulting in minimal volume.

[0043] As previously mentioned, the forces exerted on the compression spring or at least one torsion spring in the anchoring system are considerable. To avoid a short lifespan for the compression spring under such conditions, it is recommended to use the compression spring only within its operating range and to increase the diameter of the spring wire. Thus, a trade-off is made between the volume of the compression spring and its lifespan. Conversely, the torsion spring of the anchoring system according to the invention operates precisely under its designed conditions, i.e., alternating torsion, allowing the anchoring system incorporating such a torsion spring to achieve a longer lifespan.

[0044] More specifically, in the first embodiment, the anchoring system includes a torsion spring arranged along the axis of rotation (X). A first portion of the torsion spring is mounted on a frame, and a second portion of the torsion spring is mounted on a drum, the second portion being adapted to pivot relative to the first portion.

[0045] With this arrangement, the first and second stop positions can correspond to the pivoting end positions of the second portion of the torsion spring relative to the first portion. According to a preferred alternative, the first and second stop positions are contained between the pivoting end positions of the second spring portion of the spring relative to the first portion (e.g., by means of an external mechanical stop as described above). When the drum is in use, not rotating continuously to the end position advantageously avoids unnecessarily reducing the lifespan of the torsion spring.

[0046] In a second embodiment of the anchoring system according to the invention, the cable anchoring system includes at least two torsion springs mounted in series and arranged along a rotation axis (X). In a variation of the anchoring system including two torsion springs mounted in series, a first portion of the first torsion spring may be mounted on a frame, a first portion of the second torsion spring may be mounted on a drum, and a second portion of the first torsion spring may be rigidly connected to a second portion of the second torsion spring, the first portion of the first torsion spring or the first portion of the second torsion spring being adapted to pivot relative to the second portion of the first torsion spring or the second portion of the second torsion spring, respectively.

[0047] For a given side surface (S), the tandem arrangement of the two torsion springs advantageously allows the angle between the first and second stop positions relative to the axis of rotation (X) to be doubled, and thus increases the length of a portion of the side surface (S) measured in the plane (P) along which the cable is wound and / or unwound. In other words, this allows for an increase in the permitted cable travel. Therefore, if the angle between the first and second stop positions relative to the axis of rotation (X) with the torsion springs is between 0° and 30°, the tandem arrangement of the two torsion springs advantageously allows the angle between the first and second stop positions to be increased to an angle between 0° and 60°.

[0048] In other variations, the anchoring system includes at least three torsion springs mounted in series to further increase the angle between the first and second stop positions, and thus increase the allowable cable travel. However, in this variation, at least one of the torsion springs mounted in series (the intermediate torsion spring) is neither mounted on the drum nor on the frame, such that the torsion spring and connecting portion on either side of the intermediate spring must bear the intermediate torsion spring and withstand the force generated by it. Therefore, a variation with only two torsion springs mounted in series is preferred.

[0049] By way of example, when the bending radius of a portion of the side surface (S) is measured to be 575 mm, the diameter of the cable is measured to be 50 mm, and the distance d' between the cable measured in the plane (P) and a straight line in the plane (P) parallel to the cable (which intersects the axis of rotation (X)) is advantageously equal to the bending radius of the portion of the side surface (S), the travel angle between 0° and 60° between the first and second stop positions allows a portion of the cable with a length measured in the plane (P) between 0 and approximately 630 mm to be swept. Specifically, the arc length l of a portion of the cable can be calculated as follows: This length allows for a cable travel of approximately 300 mm in both the winding and unwinding directions. The inventors consider this travel to be the ideal travel of the cable from the neutral position. Specifically, the ideal travel that keeps the cable taut to avoid damage is equal to the product of the maximum speed of the spreader and the reaction time of the feedback loop of the electronically controlled winder. The maximum linear speed imparted to the spreader by the motor is typically between 150 m / min or 2.5 m / s and 240 m / min or 4 m / s, and the reaction time of the electronically controlled winder is approximately 75 ms. Therefore, the ideal travel from the neutral position in both the unwinding and winding directions of the cable on the drum is practically approximately 300 mm. The tandem arrangement of two or more torsion springs advantageously allows for this cable travel while limiting volume. As mentioned earlier, such a travel length cannot be reasonably achieved using compression springs.

[0050] Each torsion spring may include a metal spring arranged along an axis (X). For example, and as shown... Figure 8 As shown, the cable anchoring system includes a single metal torsion spring 10, with a first coil 11a at a first end of the spring rigidly connected to a frame 2, and a second coil 11b at a second end of the spring rigidly connected to a drum 1. In this configuration, the anchoring system may further include a shaft 12 rigidly connected to the frame 2 and oriented along the axis of rotation (X), and a bearing (not shown) rigidly connected to the drum 1. In this way, the bearing and shaft 12 provide rotational guidance of the drum 1 relative to the frame 2 along the axis of rotation (X). Alternatively, the shaft may be rigidly connected to the drum, and the bearing rigidly connected to the frame. For example, the shaft 12 is arranged inside the coil of the metal torsion spring 10. Preferably, Figure 8 The anchoring system further includes at least one damper (not shown), such as a hydraulic, pneumatic, metallic, or elastic (tensioner) damper, which enables the damping of impacts.

[0051] The first and second stop positions of the drum can be set by the first and second limit torsion angles (the permanent deformation of the spring) of the metal torsion spring 10, respectively. Alternatively, the diameter of the shaft 12 can be carefully selected such that the first and second stop positions correspond to the torsion angles of the torsion spring 10, at which the torsion spring is "locked" by the shaft 12. In a preferred variation, the cable anchoring system further includes at least two mechanical stops that lock the rotation of the drum before the individual metal spring 10 reaches the first and second limit torsion angles. Each mechanical stop includes, for example, a first portion fixed to the frame and a second portion fixed to the drum: as the drum rotates about the axis of rotation (X), the second portion of the mechanical stop then abuts against the first portion of the mechanical stop to lock, thereby stopping the rotational movement of the drum at the stop position. Preferably, at least one mechanical stop is a progressive rubber stop known to those skilled in the art.

[0052] Alternatively and advantageously, each torsion spring may include a rigid and hollow outer shaft, a rigid central shaft housed within the rigid and hollow outer shaft, and a damper configured to dampen the torsional movement of the rigid and hollow outer shaft relative to the rigid central shaft. In the anchoring system, the rigid central shaft and the rigid and hollow outer shaft are oriented along the axis of rotation (X).

[0053] In a particular configuration of the anchoring system comprising a single torsion spring (which includes a rigid and hollow outer shaft, a rigid central shaft housed within the rigid and hollow outer shaft, and a damper as described above), the rigid central shaft may be mounted on the drum and the rigid and hollow outer shaft may be mounted on the frame, such that the torsion / pivot of the rigid and hollow outer shaft relative to the rigid central shaft about a rotational axis (X) provides rotational guidance of the drum relative to the frame along the same axis. In other words, in this configuration, the torsion spring acts as both a bearing guiding the rotational movement of the drum relative to the frame and a damper for the forces generated by said movement. Alternatively, the rigid central shaft may be mounted on the frame and the rigid and hollow outer shaft may be mounted on the drum.

[0054] This torsion spring, comprising a rigid central shaft housed within a rigid and hollow outer shaft, advantageously eliminates the need for other devices used for rotatably mounting the drum relative to the frame, such as roller bearings or bushings (see [link to relevant documentation]). Figure 5In this configuration, a roller bearing 9 is used in conjunction with a compression spring 8. The roller bearing 9 allows the drum to rotate about the axis of rotation (X), and the compression spring dampens the movement. In practice, the roller bearing or pad is unsuitable for the operating conditions of an anchoring system mounted on a lifting device (continuous operation within a limited rotation angle without any full rotation, and significant vibration) and wears out quickly, thus limiting the lifespan of the anchoring system. Alternatively, the roller bearings can be made oversized (in other words, larger bearings with even larger balls) so that they can withstand the heavy static loads they experience on the anchoring system during operation due to the limited rotation angle without unduly reducing the lifespan of the anchoring system. However, such oversized bearings are more expensive and bulkier. Conversely, torsion springs, traditionally used for vibration damping pads, are perfectly suited to these operating conditions.

[0055] Preferably, the damper of the torsion spring includes a plurality of elastomeric elements, such as four elastomeric elements, arranged between a rigid central axis and a rigid outer axis.

[0056] The term "elastomer" refers to an elastic polymer material. Natural or synthetic rubber and chloroprene rubber are examples of elastomers within the meaning of this invention.

[0057] Compared to metal springs, torsion springs incorporating elastomeric elements offer several advantages. For example, torsion springs incorporating elastomeric elements are specifically designed to resist and absorb vibrations and sustained shocks, conditions commonly encountered when such springs are mounted on frames used in elevators. In contrast, under the same conditions of vibration and sustained shock, steel springs quickly demonstrate their limitations: sustained stress causes cracking in metal springs much faster than in elastomeric elements. Consequently, torsion springs incorporating elastomeric elements do not wear out as quickly as steel springs.

[0058] Furthermore, elastomeric elements are highly susceptible to corrosion. Therefore, springs incorporating elastomeric elements require very little maintenance, and their lifespan is not diminished even when used in corrosive environments, such as coastal areas. In contrast, metal springs, particularly compression springs, are more susceptible to corrosion, and painting is insufficient to satisfactorily improve corrosion resistance: impacts, cracks, or paint adhesion defects can be enough to induce corrosion and metal cracking. Other known physicochemical processes aimed at increasing corrosion resistance, particularly those involving heating, have been ruled out to avoid adverse effects on the material's properties, especially its ability to withstand normal deformation in compression or elongation.

[0059] The dimensions of such a torsion spring with an elastomeric element can be determined, particularly by selecting the material and size of the elastomeric element, to obtain the desired angle between the first and second stop positions, for example, 30°, or even 45°, and to ensure that the torsion spring can withstand the forces it will experience when used on the elevator without affecting its volume on the frame and without compromising its manufacturability. In the case of a compression spring, increasing the strength of the compression spring involves increasing the wire diameter of the compression spring and thus its volume, as well as its manufacturing difficulty.

[0060] Finally, unlike metal springs, torsion springs, which include elastomeric elements, are more overload resistant than metal springs. Furthermore, the failure of the elastomeric element allows for continued operation in a fault-tolerant mode, whereas the breakage of a single torsion or compression spring would immediately shut down the system. Operation in fault-tolerant mode allows for continued operation at a reduced speed, where applicable, until the defective component can be replaced.

[0061] Each elastomeric element functions not only as a spring but also as a damper. The spring generates a return force proportional to the torsional angle, which compensates for changes in force within the cable. The damper generates a dissipative force proportional to the speed of the torsional motion, which prevents the stop from reaching full speed. Therefore, unlike compression springs and metal torsion springs, torsion springs incorporating such elastomeric elements advantageously eliminate the need for adding another damper, such as a hydraulic, pneumatic, metallic, or elastic (tensioner) damper.

[0062] More precisely, reference Figure 6 Each torsion spring 10 may include a first metallic, hollow square-based prism 11, a second metallic, hollow square-based prism 12 angularly offset from the first prism 11 and housed within it, and each elastomeric element may be a cylinder 13 arranged at each corner of the first prism between the first prism 11 and the second prism 12. In this configuration, the first prism 11 may be rigidly connected to the frame (in reverse to the drum), and the second prism 12 may be rigidly connected to the drum (in reverse to the frame). This configuration of torsion springs, including the second prism housed within the first prism and the elastomeric elements at each corner of the first prism, advantageously allows for a large travel angle, approximately 30° for each torsion spring.

[0063] In a specific configuration where two torsion springs are connected in series, the inner second prism 12 of the first torsion spring can be connected to the inner second prism 12 of the second torsion spring. The outer first prisms 11 of the first and second torsion springs can be connected to the drum and the frame, respectively. This configuration of the first prisms 11 and the second prisms 12 is particularly advantageous because each first prism 11 can be very easily attached to the drum or the frame, for example, by means of a strip and two components including bolts or rivets or welds. Furthermore, the second prisms 12 can be easily connected using techniques known to those skilled in the art, for example, by means of a shaft having a square base and two axial stops.

[0064] Alternatively, the first prism 11 of the first torsion spring can be connected to the first prism 11 of the second torsion spring, and the second prism 12 of the first torsion spring and the second prism 12 of the second torsion spring can be connected to the drum and the frame, respectively.

[0065] Alternatively, the first prism 11 of the first torsion spring can be connected to the frame or the drum, and the second prism 12 of the second torsion spring can be connected to the drum or the frame, with the second prism 12 of the first torsion spring connected to the first prism 11 of the second torsion spring.

[0066] The torsion spring can both guide the rotation of the drum about the axis of rotation (X) and compensate for changes in cable tension, which does not limit the scope of the invention. The invention extends to any anchoring system that includes a torsion spring configured to guide the rotation of the drum and compensate for changes in cable tension.

[0067] In addition to the aforementioned cable anchoring system implementation, each spring may include two sets of springs mounted in parallel. The first portion of each set is connected to the frame, and the second portion is connected to the drum. Each set of springs can be understood as a single spring or at least two springs mounted in series. Parallel mounting advantageously prevents the force of the springs from being doubled for the same angle of rotation of the drum about the axis (X). Furthermore, parallel mounting allows the force borne on the frame to be distributed on either side of the drum, thus minimizing the shear force on the springs.

[0068] By way of example, Figures 7A to 7B Figure 7D The diagram illustrates a specific configuration of a spring comprising a first group of springs and a second group of springs. The first group of springs consists of a first torsion spring 10a mounted in series with a second torsion spring 10b, and the second group of springs consists of a third torsion spring 10c mounted in series with a fourth torsion spring 10d. The first and second groups of springs are mounted parallel to each other. Furthermore, the four springs are arranged along the axis of rotation (X). In particular, Figure 7BThe configuration of the reel in a neutral position is shown. Figure 7C This illustrates a scenario where the cable is under-tensioned. Figure 7D This illustrates a scenario of excessive tension on a cable.

[0069] Figure 7A illustrates a specific embodiment of a torsion spring in conjunction with a spool, wherein the spool has an elliptical shape in plane (P), and the axis of rotation (X) intersects plane (P) at the center of a circle tangent to the wound and / or unwound portion of the cable, the radius of which is equal to the bending radius of the portion. However, any combination of a torsion spring with a spool of any other shape remains within the scope of this invention.

[0070] As previously described, the first and second stop positions may correspond to the limit torsional angles of the torsion spring or a group of torsion springs. Alternatively, the first and second stop positions may be slightly offset so that the limit torsional angle of the torsion spring is never reached, for example by means of a rubber mechanical stop as previously described.

[0071] The present invention also relates to a lifting device, comprising: - Lifting gear, - Anchoring system, comprising a frame and a drum as described above, the frame being attached to the lifting device and the drum being attached to the frame. - A winding machine, suitable for attachment to an elevator. - A cable, the first end of which is anchored to the drum of the anchoring system by being fixedly wound around the side surface of the drum at least two turns, and the second end of which is wound on a winding machine.

[0072] Finally, the present invention relates to an elevator comprising the lifting device as described above. According to a specific embodiment of the invention, the elevator is a crane, gantry crane, or forklift. For example, an elevator is a crane used for loading or unloading containers on a container ship.

[0073] According to a specific embodiment of the elevator, the elevator further includes a lifting device, a second spreader, and an intermediate platform as described above. For example, the elevator is an STS crane, and the spreader of the lifting device is used to move containers between the ship and the intermediate platform, while the second spreader is used to move the containers between the platform and the dock.

[0074] In a particular embodiment of a lift having two lifting devices, the second lifting device is included in a second lifting device, which can be implemented according to any embodiment of the lifting device as described above.

[0075] Alternatively, the lift does not include any second winding machine, so that the second spreader is not powered by a cable connected to the winding machine. For example, the second spreader is powered by a second cable stored in a basket.

Claims

1. A cable (3) anchoring system, comprising: -Framework (2) - A spool (1) rotatably mounted on the frame about a rotation axis (X), the spool having a side surface (S) about an axis (Y) parallel to the rotation axis (X), the spool rotating about the rotation axis (X) in response to changes in the mechanical tension of the cable, the spool being adapted to allow the cable to travel by winding and / or unwinding the cable along a portion of the side surface. - At least one torsion spring (10, 10a, 10b, 10c, 10d), said at least one torsion spring being arranged between the drum and the frame to compensate for changes in cable tension.

2. The cable anchoring system according to claim 1, wherein, The at least one torsion spring includes a first portion mounted on a frame and a second portion mounted on a drum, the second portion being adapted to pivot relative to the first portion.

3. The cable anchoring system according to claim 1, comprising at least two torsion springs arranged in series.

4. The cable anchoring system according to claim 3, wherein, The first part of the first spring is mounted on the frame, the first part of the second spring is mounted on the drum, and the second part of the first spring is rigidly connected to the second part of the second spring.

5. The cable anchoring system according to any one of claims 1 to 4, wherein, Each torsion spring (10) includes a rigid and hollow outer shaft (11), a rigid central shaft (12) housed inside the outer shaft (11), and a damper configured to dampen the torsional motion of the rigid and hollow outer shaft relative to the rigid central shaft.

6. The cable anchoring system according to claim 5, wherein, The damper of the torsion spring includes a plurality of elastomeric elements (13) arranged between a rigid central shaft (12) and a rigid and hollow outer shaft (11).

7. The cable anchoring system according to claim 6, wherein, Each torsion spring includes a first metal hollow square-base prism forming a rigid and hollow outer shaft, and a second prism forming a central shaft, the second prism being arranged in the first prism with an angular offset relative to the first prism, wherein each elastomeric element is a cylinder arranged at each corner of the first prism between the first prism and the second prism.

8. The cable anchoring system according to claim 7, comprising two torsion springs connected in series, wherein the second square base prism of the first torsion spring is connected to the second square base prism of the second torsion spring.

9. The cable anchoring system according to any one of claims 1 to 8, wherein, The at least one torsion spring is configured to dampen the force generated by the rotation of the drum about the axis of rotation (X) between a first stop position and a second stop position of the drum, the first stop position and the second stop position being angularly offset from the axis of rotation (X) by an angle between 0° and 90°, preferably between 0° and 60°.

10. The cable anchoring system according to any one of claims 1 to 9, comprising at least two sets of torsion springs arranged in parallel, a first portion of each set of torsion springs mounted on a frame, and a second portion of each set of springs mounted on a drum.

11. The cable anchoring system according to any one of the preceding claims further includes a compression spring and / or a tension spring, the compression spring and / or tension spring comprising a first portion mounted on a frame and a second portion mounted on a drum.

12. A lifting device, comprising: - Lifting device (4), which includes at least one component for securing the load to be lifted, - A cable anchoring system according to any one of claims 1 to 11, comprising a frame (2) and a reel (1), the frame being attached to a lifting device and the reel being attached to the frame. - A winding machine, suitable for attachment to an elevator. - Cable (3), the first end of which is anchored to the drum (1) of the anchoring system by being fixedly wound around the side surface of the drum at least two turns, and the second end of which is wound on the winding machine.

13. A lift (6), such as a crane, gantry, or forklift, comprising the lifting device according to claim 12.

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