Coupling unit for coupling a rotatable threaded engagement of a bolt extending tool for extending a bolt of a

Abstract

A coupling unit (12) for coupling a rotatable threaded engagement means (4) of a bolt elongation tool (1) for elongation of a bolt (2) of a flanged connection (3) with the bolt (2) wherein the bolt elongation tool (1) comprises a threaded engagement means (4) and an expansion means (5) connected to the threaded engagement means (4), characterized in that the coupling unit comprises: a lowering unit (6) for lowering the threaded engagement means (4) and the expansion means (5) connected to the threaded engagement means (4); a lowering means (4) configured to lower the threaded engagement means (4) towards the flange connection (3) onto the bolt (2); and a rotation unit (7) configured to rotate the thread engagement means (4) at a rotation speed corresponding to the thread feed of the bolt (2) when the thread engagement means (4) is lowered.

Description

Technical Field

[0001] The invention relates to a coupling unit for a rotatable threaded engagement device of a bolt lengthening tool according to the preamble of claim 1 . Background Art

[0002] In the field of modern energy production, wind turbines play an important role in providing renewable, sustainable and clean energy to the energy market. A wind turbine comprises a tower on which a rotor is mounted, which is connected to a generator. The tower can reach a height of 100 meters, 150 meters or even higher, depending on the specific requirements such as the location of the wind turbine. The tower consists of several pipe sections with a length of, for example, 20 meters or 30 meters. These pipe sections are connected by circular flange connections on each side of the pipe section. When the wind turbine is erected on site, the pipe sections are assembled together and connected by means of joint circular flange connections using bolts and nuts. A large number of large-sized bolts, usually hundreds of them, are required to achieve the required connection stiffness and strength. In order to achieve a suitably defined stiffness and strength in the joint, all bolts must be bolted to a predefined preload or torque and according to a specific bolt tightening pattern.

[0003] This tightening operation was previously performed manually using torque wrenches or similar tools. As a result, the construction of wind turbine towers is very labor-intensive. One of the main challenges when assembling wind turbines is to tighten the bolts of the flange connections correctly to achieve the necessary clamping force. The torque required for this application is very high, so these tools are expensive and prone to errors or mechanical failures. Another way to achieve the necessary clamping force is to lengthen the bolt by applying a tensile force to the bolt using a bolt lengthening tool and then tighten a lock nut on the bolt while the tensile force is still applied. Once this lock nut has been tightened, the tensile force is released and the bolt returns to its original length, thereby clamping the lock nut. By adopting this method, a very precisely defined clamping force can be achieved.

[0004] However, bolt lengthening tools according to the prior art have certain disadvantages. They include a threaded engagement device which has to be screwed onto the bolt and then used to apply a tensile force to the bolt. This screwing-on process is time-consuming and prone to errors. Due to the size of the bolt and the weight of such a threaded engagement device, the threaded engagement device may lock with the threads of the bolt during this process, resulting in an imperfect or insufficient clamping between the two components. When this happens, the threaded engagement device must be unscrewed from the bolt and the process restarted. In addition, due to the weight of the threaded engagement device and the bolt lengthening tool as a whole, the first few threads of the bolt must resist high friction and high loads when the threaded engagement device is screwed onto the bolt. This may result in damage to the bolt and / or the threaded engagement device. Summary of the invention

[0005] Therefore, the technical problem of the present invention is to alleviate these problems of the prior art.

[0006] This problem is solved by providing a coupling unit according to the subject matter of claim 1 and a bolt lengthening system according to the subject matter of claim 7 .

[0007] The coupling unit according to the present invention is configured to couple a rotatable threaded engagement device of a bolt extension tool for extending a bolt of a flange connector with the bolt. The bolt extension tool comprises: the rotatable threaded engagement device, which is configured to be screwed onto the bolt; and an expansion device, which is connected to the threaded engagement device and is configured to apply a force substantially perpendicular to and away from the flange connector on the threaded engagement device when the threaded engagement device is engaged with the thread of the bolt. The coupling unit according to the present invention comprises: a lowering unit, which is configured to lower the threaded engagement device onto the bolt toward the flange connector; and a rotating unit, which is configured to rotate the threaded engagement device at a rotation speed corresponding to the thread feed of the bolt when the threaded engagement device is lowered. By matching the rotation speed of the threaded engagement device with the lowering speed of the lowering unit and the thread feed of the bolt, automatic matching of the thread of the threaded engagement device and the bolt can be achieved. Therefore, the friction between the thread of the threaded engagement device and the thread of the bolt is reduced, and the threaded engagement device is easily screwed onto the bolt. This reduces the likelihood of damaging the threaded engagement means and the bolt and reduces the risk of having to unscrew the threaded engagement means from the bolt and re-screw the threaded engagement means onto the bolt to achieve adequate threaded engagement. The coupling unit according to the invention provides an almost weightless threaded engagement, with only a small vertical force being applied to the thread from the bolt extension tool.

[0008] According to a preferred embodiment of the coupling unit according to the invention, the coupling unit comprises a height compensation unit, which is configured to support the threaded engagement device. The height compensation unit comprises a free play in the descending direction of the descending unit, and the threaded engagement device is displaceable along the free play of the height compensation unit when the threaded engagement device is supported by the height compensation unit. By providing a free play in the descending direction, the coupling unit according to the invention allows the threaded engagement device of the bolt extension tool to rotate freely for a certain period of time when the threaded engagement device is lowered onto the bolt. As a result, the thread of the bolt can be matched with the threaded engagement device without applying excessive forces to the uppermost thread of the bolt.

[0009] Preferably, the lowering unit comprises a linear motor. Alternatively, the lowering unit may also be implemented by a mechanical arm connected to a series of gears or chain drives. Other mechanical ways of implementing the lowering unit will be apparent to those skilled in the art. These options provide a robust and stable means of propulsion.

[0010] The coupling unit according to the present invention preferably further comprises a driving unit, which is configured to move the bolt lengthening tool along the flange connection. Thus, the bolt lengthening tool can automatically tighten all bolts of the flange connection.

[0011] The coupling unit according to the present invention preferably comprises a centering unit, which is configured to align the central axis of the threaded engagement device with the central axis of the bolt, thereby preventing the threaded engagement device from being misaligned with the thread on the bolt.

[0012] The problem of the present invention is also solved by providing a bolt extension system according to claim 7, comprising a coupling unit according to the present invention and a bolt extension tool for extending a bolt of a flange connection. The bolt extension tool comprises: a thread engagement device, which is configured to be screwed onto the bolt; and an expansion device, which is connected to the thread engagement device and is configured to exert a force on the thread engagement device substantially perpendicular to and away from the flange connection when the thread engagement device is engaged with the thread of the bolt. Thus, a complete system comprising the bolt extension tool and the coupling unit is provided.

[0013] Preferably, the expansion device of the bolt lengthening tool of the bolt lengthening system according to the present invention comprises a hydraulic cylinder. The advantage of the hydraulic cylinder is that it provides a considerable force while still maintaining a small outer dimension.

[0014] According to a preferred embodiment of the bolt extension system, the bolt extension tool comprises a locking nut tightening device, which is configured to tighten a locking nut screwed onto the bolt while the expansion device applies a force to the threaded engagement device. This enables the bolt extension tool to tighten the locking nut while the bolt is in an extended state. Thus, a precisely defined clamping force of the flange connection can be achieved.

[0015] The height compensation unit of the bolt extension system according to the present invention may further comprise a free play measuring device, which is configured to stop or reduce the lowering speed of the lowering unit when the threaded engagement device has been displaced a predetermined distance along the free play. By measuring the distance along the free play that the threaded engagement device has used, it can be ensured that the threaded engagement device has correctly engaged the thread of the bolt. If more than the predetermined distance along the free play has been used, it means that the threaded engagement device has not engaged with the thread and the bolt extension tool is not correctly aligned with the bolt, or the thread of the bolt or the threaded engagement device is damaged. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The bolt lengthening tool and the bolt lengthening system of the present invention as well as preferred and alternative embodiments will be described below with reference to the accompanying drawings.

[0017] Figure 1 The bolt extension system according to the invention is shown in front view.

[0018] Figure 2 The bolt lengthening system according to the invention is shown in a side view.

[0019] Figure 3 The bolt lengthening system according to the invention is shown in a perspective view. DETAILED DESCRIPTION

[0020] The bolt extension system 13 according to the present invention is as follows Figure 1 The bolt extension system 13 comprises a bolt extension tool 1 and a coupling unit 12 according to the present invention. The bolt extension tool 1 is configured to extend the bolt 2 of the flange connection 3, which is also Figure 1 . The flange connection 3 is held together by a series of bolts 2, wherein a locking nut 10 is tightened on each bolt 2 to achieve a predefined clamping force. The bolt extension tool 1 comprises a rotatable threaded engagement device 4, which is configured to be screwed onto the bolt 2. The threaded engagement device 4 is also Figure 2 It is shown in Figure 2 yes Figure 1 . The threaded engagement device 4 preferably comprises a thread adapted to engage with the threads of one or more or all of the bolts 2 of the flange connection 3. In addition, the bolt extension tool 1 comprises an expansion device 5 connected to the threaded engagement device 4, the expansion device 5 being configured to exert a force F substantially perpendicular to and away from the flange connection 3 on the threaded engagement device 4 when the threaded engagement device 4 engages with the threads of the bolts 2. The force F is Figure 1 and Figure 2Indicated by arrows. Preferably, the expansion device 5 comprises a hydraulic cylinder. According to a preferred embodiment of the bolt lengthening system 13, the bolt lengthening tool 1 is supported on the flange connection 3 when applying the force F to the threaded engagement device 4.

[0021] The coupling unit 12 according to the invention comprises a lowering unit 6, which is configured to lower the threaded engagement device 4 of the bolt lengthening tool 1 onto the bolt 2 towards the flange connection 3. The lowering unit 6 preferably comprises a linear motor and is preferably suitable for being arranged on the top of the bolt lengthening tool 1. Alternatively, the lowering unit 6 can also be realized by a mechanical arm, which is preferably connected to a series of gears or chain drives. Other mechanical means for realizing the lowering unit 6 are obvious to those skilled in the art. The coupling unit 12 is configured to lower the threaded engagement device 4 of any bolt lengthening tool 4 known in the prior art.

[0022] Furthermore, the coupling unit 12 according to the invention comprises a rotation unit 7, which is configured to rotate the threaded engagement device 4 when the threaded engagement device 4 is lowered, and its rotation speed corresponds to the thread feed of the bolt 2. The rotation unit 7 can be directly connected to the lowering unit 6, for example, mechanically, or indirectly connected to the lowering unit 6 via a sensor that measures the position of the lowering unit 6. By rotating the threaded engagement device 4 at a rotation speed corresponding to the thread feed of the bolt 2, the process of screwing the threaded engagement device 4 onto the bolt 2 is synchronized with the downward movement generated by the lowering unit 6. This results in a smooth engagement between the thread of the bolt 2 and the threaded engagement device 4, reducing the friction between the threads and the forces applied to the threaded engagement device 4 and the bolt 2. As a result, the wear on the threaded engagement device 4 is reduced, and the possibility of locking due to increased friction when tightening the threaded engagement device 4 is reduced or even eliminated. The coupling unit 12 according to the invention can be manually operated, or it can also be semi-automatic or fully automatic. For example, the rotation unit 7 can include an electric motor.

[0023] According to a preferred embodiment of the coupling unit 12 of the present invention, the coupling unit 12 comprises a height compensation unit 8, which is configured to support the threaded engagement device 4. The height compensation unit 8 is Figure 2. The height compensation unit 8 comprises a free play along the descending direction LD of the descending unit 6, and the threaded engagement device 4 can be displaced along the free play of the height compensation unit 8 when the threaded engagement device 4 is supported by the height compensation unit 8. By providing a free play along the descending direction LD of the descending unit 6, the threaded engagement device 4 can contact the upper end of the bolt 2 facing away from the flange connection 3 without being immediately pressed onto the thread of the bolt 2 by the descending unit 6. Therefore, the threaded engagement device 4 can be rotated a certain degree when leaning against the bolt 2, so that the thread of the bolt 2 is aligned with the thread of the threaded engagement device 4. This greatly reduces the stress on the first thread of the bolt 2 and reduces the risk of damaging the threaded engagement device 4 or the bolt 2. The free play can be, for example, 8 mm, and a free play of 4 mm is usually used when the threaded engagement device 4 is engaged with the thread of the bolt 2. The height compensation unit 8 can also include a free play measuring device, which is not shown in the figure, which is configured to stop or reduce the descending speed of the descending unit 6 when the threaded engagement device 4 has moved a predetermined distance along the free play. By measuring the distance along the free play that the thread engaging device 4 has been used, it can be ensured that the thread engaging device 4 is properly engaging the threads of the bolt 2. If more than a predetermined distance along the free play has been used, this means that the thread engaging device 4 has not engaged the threads and the bolt extension tool 1 is not properly aligned with the bolt 2, or the threads of the bolt 2 or the thread engaging device 4 are damaged.

[0024] like Figure 1 and Figure 3 As shown, the coupling unit 12 according to the invention preferably also includes a drive unit 11, which is configured to move the bolt extension tool 1 along the flange connection 3. The preferred embodiment of the coupling unit 12 shown in the figure includes two drive units 11. The drive unit 11 can, for example, include a chain drive or a wheel drive. Other propulsion methods suitable for the drive unit 11 are generally known to those skilled in the art. The drive unit 11 enables the coupling unit 12 according to the invention to operate autonomously and automatically place the bolt extension tool 1 above the bolt 2 to tighten a series of locking nuts 10 of the flange connection 3.

[0025] Preferably, the coupling unit 12 further comprises a centering unit, which is not shown in the figure and is configured to align the central axis of the threaded engagement device 4 with the central axis of the bolt 2. Thus, the advantage of avoiding the threads of the threaded engagement device 4 and the threads of the bolt 2 being misaligned is achieved.

[0026] The bolt extension system 13 according to the present invention comprises a coupling unit 12 according to the present invention and a bolt extension tool 1 for extending a bolt 2 of a flange connection 3. The bolt extension tool 1 comprises a threaded engagement device 4 configured to be screwed onto the bolt 2 and an expansion device 5 connected to the threaded engagement device 4, the expansion device 5 being configured to exert a force F substantially perpendicular to and away from the flange connection 3 on the threaded engagement device 4 when the threaded engagement device 4 is engaged with the thread of the bolt 2. Preferably, the expansion device 5 comprises a hydraulic cylinder. In addition, the bolt extension tool 1 may preferably comprise a locking nut tightening device 9, which is arranged at the Figure 1 and is configured to tighten the locking nut 10 screwed on the bolt when the expansion device 5 applies a force F to the threaded engagement device 4. Therefore, the bolt extension tool 1 according to the present invention can be used to extend the bolt 2 and fix the bolt 2 with the locking nut 10 at the same time.

[0027] According to a preferred embodiment of the bolt extension system 13 of the present invention, the coupling unit 12 includes the height compensation unit 8 as described above, wherein the height compensation unit 8 includes a free clearance measuring device, which is configured to stop or reduce the descending speed of the descending unit 6 when the threaded engagement device 4 has been displaced a predetermined distance along the free clearance.

Claims

1. A coupling unit (12) for coupling a rotatable threaded engagement device (4) of a bolt lengthening tool (1) for lengthening a bolt (2) of a flange connection (3) with the bolt (2), wherein the bolt lengthening tool (1) comprises: The threaded engagement device (4) is configured to be screwed onto the bolt (2); and an expansion device (5) connected to the threaded engagement device (4) and configured to exert a force (F) on the threaded engagement device (4) substantially perpendicular to and away from the flange connection (3) when the threaded engagement device (4) engages with the thread of the bolt (2), It is characterized in that The coupling unit (12) comprises: a lowering unit (6) configured to lower the threaded engagement device (4) onto the bolt (2) toward the flange connection (3); and a rotating unit (7) configured to rotate the threaded engagement device (4) at a rotation speed corresponding to the thread feed of the bolt (2) when the threaded engagement device (4) is lowered.

2. The coupling unit (12) according to claim 1, characterized in that The coupling unit (12) comprises a height compensation unit (8), which is configured to support the threaded engagement device (4), wherein the height compensation unit (8) comprises a free play along the descending direction (LD) of the descending unit (6), and when the threaded engagement device (4) is supported by the height compensation unit (8), the threaded engagement device (4) can be displaced along the free play of the height compensation unit (8).

3. The coupling unit (12) according to claim 1 or 2, characterized in that The descending unit (6) comprises a linear motor.

4. The coupling unit (12) according to any one of claims 1 to 3, characterized in that The coupling unit (12) comprises a drive unit (11) which is configured to move the bolt extension tool (1) along the flange connection (3).

5. The coupling unit (12) according to any one of claims 1 to 4, characterized in that The coupling unit (12) comprises a centering unit configured to align a center axis of the threaded engagement device (4) with a center axis of the bolt (2).

6. A bolt lengthening system (13), comprising a coupling unit (12) according to any one of claims 1 to 5 and a bolt lengthening tool (1) for lengthening a bolt (2) of a flange connection (3), wherein the bolt lengthening tool (1) comprises: a threaded engagement device (4) configured to be screwed onto the bolt (2); and an expansion device (5) connected to the threaded engagement device (4) and configured to exert a force (F) on the threaded engagement device (4) substantially perpendicular to and away from the flange connection (3) when the threaded engagement device (4) engages with the thread of the bolt (2).

7. The bolt extension system (13) according to claim 6, characterized in that: The expansion device (5) of the bolt extension tool (1) comprises a hydraulic cylinder.

8. The bolt extension system (13) according to claim 6 or 7, characterized in that: The bolt extension tool (1) comprises a locking nut tightening device (9) configured to tighten a locking nut (10) screwed on the bolt (2) while the expansion device (5) applies the force (F) on the threaded engagement device (4).

9. The bolt extension system (13) according to any one of claims 6 to 8, characterized in that: The coupling unit (12) comprises a height compensation unit (8) according to claim 2, wherein the height compensation unit (8) comprises a free play measuring device, which is configured to stop or reduce the descending speed of the descending unit (6) when the threaded engagement device (4) has been displaced a predetermined distance along the free play.

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