EP3181307A1

EP3181307A1 - Versatile handling tool

Info

Publication number: EP3181307A1
Application number: EP15201300.9A
Authority: EP
Inventors: Joergen Klitgaard
Original assignee: Siemens AG
Current assignee: Siemens Gamesa Renewable Energy AS
Priority date: 2015-12-18
Filing date: 2015-12-18
Publication date: 2017-06-21
Anticipated expiration: 2035-12-18
Also published as: EP3181307B1; DK3181307T3

Abstract

The invention relates to a device (10) for handling a tool (21) for tightening a fastener, wherein the device (10) is suitable to assist assembly of two components of a wind turbine. The device (10) comprises a mast (11), a jib (12) and a balancing unit (13), wherein the balancing unit (13) is attached at the jib (12), is arranged and prepared to be connected to the tool (21), and is arranged and prepared to counteract at least partially the weight of the tool (21). Furthermore, the mast (11) comprises means for raising and lowering the jib, e.g. at least two telescopic cylinders nested within each other such that the jib (12) can be raised and lowered. The invention is also directed towards a method of tightening a plurality of fasteners using such a device (10).

Description

The invention relates to a device for handling a tool for tightening a fastener. In particular, the invention relates to a portable versatile device for handling a tool too heavy to handle ergonomically safe for the operator, for instance when tightening a fastener. Furthermore, the invention relates to a method of tightening a plurality of fasteners for assembling two components of a wind turbine.
Fasteners such as bolts, screws or nuts can be tightened by various ways.
One option is to tighten a fastener manually by means of a wrench. A wrench is also referred to as a spanner and benefits from a leverage effect in order to impact the necessary torque on the fastener.
Another option to tighten a fastener is to use a torque wrench. A torque wrench is a particularly shaped and configured wrench which is specifically suited to impact the necessary torque on the fastener. Such a torque wrench can be handled manually or hydraulically or pneumatically. A hydraulic torque wrench is particularly useful if high torques have to be applied to the fastener. This is in practice typically necessary for large bolts which are designed to withstand considerable forces.
When tightening structural bolts in a wind turbine, some sort of a power tool is needed due to the size of the fasteners, which implies that a high torque, i.e. a large force, is needed to tighten such fasteners. One example of such a power tool is a hydraulic torque tool, but other types of power tools for tightening fasteners exist as well.
As the wind turbines grow bigger, the structural fasteners grow bigger as well. To give a concrete example, to tighten a M42 - M48 fastener, a hydraulic tool typically weighs 10 kilogram, which can be handled manually without the need of any assistance under normal circumstances. But with the use of bigger fasteners like M56, M64, M72 etc., the tools for tightening these fasteners are too heavy for an operator to handle ergonomically safe. One solution to this problem is to balance the tool.
Production lines tools are often assisted by some sort of tool balance. A standard tool balance is typically built with a spiral spring attached to a tapered cable drum, thereby it can provide a constant pulling force over a big working range. An example of a conventional factory workplace with a standard tool balance is shown in Figure 1.
Coming back to the portable hydraulic torque tools, a drawback of it is its weight, which may easily amount to twenty or thirty kilogram (precisely speaking, the mass of a conventional hydraulic torque wrench may easily amount to twenty or thirty kilogram). In the case that the hydraulic torque wrench has to be transported to the specific area where the fastener needs to be tightened, this may cause a challenge as the hydraulic torque wrench has to be transported normally by a service person. It is particularly challenging if the area where the hydraulic torque wrench needs to be transported to is hard to reach. In these cases, weight limitations for a man to carry tools may be present, prescribing to not exceed fifteen kilogram, for instance.
Thus, there exists the problem how to handle such tools which are too heavy to handle manually.
This problem is particularly relevant in heavy industries as, for instance, the field of wind turbines. Frequently, two components of a wind turbine, such as two parts of the nacelle, the hub or the tower, need to be assembled by fasteners, but the specific location where assembling has to take place is difficult to access. In practice, for example, service workers have to climb up the tower and fasten the two components in positions which are difficult to reach. In these situations it can be dangerous or even impossible to carry manually and to operate manually these heavy tools.
Therefore, there exists the need for a concept how to handle a heavy tool for tightening a fastener for assembling two components of a wind turbine.
This objective is solved by the independent claims. Advantageous modifications and embodiments are described in the dependent claims.
According to the invention, there is provided a device for handling a tool for tightening a fastener, wherein the device is suitable to assist assembly of two components of a wind turbine. The device comprises a mast, a jib and a balancing unit. The balancing unit is attached at the jib, is arranged and prepared to be connected to the tool, and is arranged and prepared to counteract at least partially the weight of the tool. Furthermore, the mast comprises means for raising and lowering the jib.
By this device, a versatile handling of tools which are too heavy to handle manually is provided. This is particularly advantageous for the assembly of tower segments, or components in relation to the nacelle or the hub of the wind turbine.
The device is advantageous for handling a tool with a mass exceeding an ergonomic limit for manual handling of tools.
The exact, quantitative value for the ergonomic limit for manual handling of tools may generally vary and depend on national legislation, on internal company guidelines, and on the type and intensity of work that the worker carries out with the tool.
The key aspect is that the inventive device and method is particularly advantageous for manually handling a tool which is tiring or even health-damaging if carried out regularly.
Exemplarily, a lower limit for the ergonomic limit is ten kilogram. This implies that the device is particularly advantageous for handling a tool with a mass exceeding ten kilogram.
It is furthermore noted that in practice there also exist an upper limit, until which mass the device is advantageously be used. Generally speaking, if the mass of the tool exceeds fifty kilogram, a manual use of the tool - even when supported and facilitated by the inventive device - is rather unlikely. Therefore, it can be said that the device is particularly advantageous for handling a tool with a mass falling below fifty kilogram.
In other words, the device is particularly advantageous for tools which have a weight exceeding security limits which may exist for protecting installation and servicingworkers who need to operate these tools on joints with multiple fasteners.
An example of such a tool is a torque wrench, in particular a hydraulic torque wrench.
Note that the torque wrench, and in particular the hydraulic torque wrench, is purely one example out of many tools which could be thought of to be handled with the present device. In principle, any tool which is too heavy to handle manually on a regular basis is suitable to be used in connection with the inventive device.
Advantageously, the balancing unit is attached movably at the jib of the device. This is due to the fact that the plurality of fasteners shall be reached by the tool, which is connected to the balancing unit.
Alternatively, however, the balancing unit may also be attached rigidly to the jib, and the tool, which is connected to the balancing unit, is able the plurality of fasteners by other means, e.g. by featuring connection means which are long enough to reach all fastener needed.
Examples of fasteners which can be tightened by the tool are a bolt and a nut.
Note that the inventive device can on the one side beneficially be used to initially assemble the two components of the wind turbine. On the other side, it can beneficially be used to retighten already existing assemblies by means of retightening already existing fasteners.
An example of the balancing unit which is arranged and prepared to be connected to the tool and which is arranged and prepared to counteract at least partially the weight of the tool is in principle a spring. This can be a standard tool balancer or , for instance, a gas spring. Gas springs are often both light-weight and powerful As an example, the device is used such that the resulting force which the worker has to lift when operating and working with a twenty-five kilogram hydraulic torque wrench is equivalent to a gravitational force of less than fifty Newton.
Descriptively speaking, the workers do not feel to lift twenty-five kilogram, but only five kilogram. This known concept is also referred to as tool balancing.
The invention is also directed to a method of tightening joints with multiple fasteners. The method comprises the steps of

attaching a device for handling a tool for tightening a fastener to a first section of the first component, wherein the device comprises a mast, a jib and a balancing unit, and wherein the mast comprises means for raising and lowering the jib,
placing the tool at the first fastener to be tightened,
connecting the tool with the balancing unit,
raising the jib by means of the telescopic cylinders of the mast such that the weight of the tool is at least partially counteracted,
tightening the first fastener by means of the tool,
moving the tool along the jib of the device,
tightening the second fastener by means of the tool, continue this sequence on the fasteners that are within the range of the jib, and
lowering the jib such that the tension on the balancing unit is relieved.

A key aspect of the inventive method is that, by means of e.g. telescopic cylinders of the mast, tension on the tool can be applied and relieved selectively. Note that if tension on the tool by means of the balancing unit is applied, the gravitational force which is due to the mass of the tool may be reduced significantly. To give a concrete example, the mass of the tool being thirty kilogram may be virtually reduced to less than five kilogram by putting tension on the tool via the balancing unit. This is advantageous for the person operating the tool because then only the virtual mass of less than five kilogram has to be lifted, instead of the true mass of approximately thirty kilogram.
Applying tension on the balancing unit is done by raising e.g. the telescopic cylinders of the mast of the device. This is also referred to as raising the telescopic arm or telescopic column of the mast. Raising of the telescopic mast of the device can in principal be achieved by any means, e.g. electrically, pneumatically, hydraulically, manually, etc. In order to provide a simple, robust and light-weight tool, a preferred option is to provide a mechanical crank on the mast and to raise and lower the telescopic cylinders of the mast manually.
In the first step of the inventive method the device is attached to a specific section of the first component of the two components which need to be assembled together. This first section may for example refer to a nut or a bolt or a hole of the component. Exemplarily, one option is to choose one of the nuts which needs to be tightened and attach the foot of the mast of the device to this nut. This nut may then be referred to as the attachment nut. Once the mast of the device is firmly attached to the attachment nut, the tool, such as the hydraulic torque wrench, is placed at the first fastener to be tightened. To give a concrete example, the first fastener could be this nut which is (a) the furthest away from the attachment nut, but (b) which is still in reach of the jib of the device. This nut would then advantageously be chosen to be the first fastener where the hydraulic torque wrench is located and placed at. Subsequently, the tool is connected with the balancing unit. After that, the jib is raised by means of the telescopic cylinders of the mast. Raising can be performed for example by a mechanical crank. Due to the fact that the tool is connected with a balancing unit and the balancing unit is connected with the jib, by raising the jib a tension is put on the tool. This tension provides a force which is substantially opposite to the gravitational force of the tool. As a result, the resulting force which is experienced by the tool and which is experienced by a person operating and lifting the tool is the difference between the gravitational force and the tension force exerted by the balancing unit.
Advantageously, the jib is raised to such an extent that the weight of the tool is sufficiently reduced. To give an example, the actual mass of the tool of thirty kilogram may be reduced to less than five kilogram (or - equivalently - fifty Newton) by raising the jib by means of the telescopic arms of the mast accordingly.
Subsequently, the first fastener, e.g. the first nut, is tightened by the tool, e.g. the hydraulic torque wrench. Once the first fastener is fastened, the tool is taken from the first fastener and is moved substantially horizontally along the jib to the next fastener which needs to be tightened. Typically this is the fastener which is adjacent to the first fastener. The tool is applied to the next fastener and then this next fastener is tightened.
These steps are repeated until all fasteners within the reach of the device are tightened, wherein the reach of the device is determined by the reach of the jib. In practice, if the first fastener is chosen to be the fastener which is furthest away from the mast, the last fastener to be tightened would be the fastener which is closest to the mast.
Then, the telescopic mast is lowered such that tension on the tool is relieved. Once that the tension is relieved, the actual weight that is experienced by a person moving the device is only the weight of the device without the weight of the tool. An example for the weight of the device is a mass of approximately ten kilogram. Thus, the device can easily be moved around by a service worker.
Then, the device is advantageously attached to another section, such as another attachment nut, and the described steps of tightening all nuts being in reach within the reach of the jib can be repeated.
Note that when moving the mast from one attachment nut to the next attachment nut, the tool as such can either be connected or disconnected from the balancing unit. It is, however, important that in any case tension on the tool needs to be relieved - advantageously entirely and completely relieved. Then it is ensured that the person who is transporting the device from one attachment nut to the next one only needs to carry and move the weight of the device and not additionally also the weight of the tool.
Advantageously, during carrying out the described method, the mast is directed substantially vertically and/or the jib is directed substantially horizontally.
Note that, in practice, there might be a certain clearance when attaching the socket of the mast to the attachment nut. As a consequence, the mast, which is, for instance, perfectly vertical in an unloaded state, might incline a few degrees, e.g. two degree, when the device is loaded by connecting the tool to the balancing unit and raising the jib. One option to keep the jib horizontally although the mast is slightly inclined compared to a perfectly vertical orientation, is to connect the mast and the jib in an angle, which is slightly larger than ninety degree, e.g. ninety-two degree.
Furthermore note that the expression "substantially horizontal/ substantially vertical" includes deviations up to five percent.
As a conclusion, some aspects of the present invention can be summarized as follows: during operation, the tool is operated by hand, i.e. having a tension on it which causes the reduction of its mass experienced by the person operating the tool. The tool can be operated within the reach of the horizontal jib of the device. This allows tightening a plurality of fasteners with a tool which might be too heavy to handle manually and with a device which is simple, robust and relatively light-weight.
Embodiments of the invention are now described, by way of example only, by the accompanying drawings, of which:

Figure 1 shows a conventional factory workplace with a standard tool balance;
Figure 2 shows a device for handling a tool for tightening a fastener;
Figure 3 shows the same device as illustrated in Figure 1 from another perspective; and
Figure 4 shows the device of Figures 1 and 2 during the tightening of nuts for assembling two tower segments of a wind turbine together.

The illustration in the drawings is in schematic form. It is noted that in different figures, similar or identical elements may be provided with the same reference signs.
Figure 1 shows a conventional factory workplace with a standard tool balance. The workplace comprises a conventional device 30 with a mast 11, a horizontal jib 12 and a balancing unit 13. The balancing unit 13 is a standard tool balance. Figure 1 further shows a tool 21, which could e.g. be a tool for tightening fasteners, wherein the tool 21 is attached to the balancing unit 13.
The conventional device 30 is firmly attached to the ground. In other words, the conventional device 30 is immobile. Consequently, the items to be worked with by a worker 31, e.g. the fasteners which need to be fastened, are transported to the conventional device 30, instead of the device being transported to the fasteners.
For factory needs, this is acceptable. For installation or servicing a wind turbine, an immobile device for tightening fasteners is obviously not useful. Therefore, a versatile, portable device is needed.
Figure 2 shows such a portable device 10 for handling a tool 21 for tightening a fastener. Figure 2 is a perspective view on such a device 10. The device 10 comprises a mast 11, wherein the mast 11 comprises two telescopic cylinders, namely a first telescopic cylinder 111 and a second telescopic cylinder 112. By means of these two telescopic cylinders 111, 112, the length of the mast in longitudinal direction can be varied. An extension or a reduction of the length of the mast 11 can be achieved by operating a crank 113. The crank 113 enables raising or lowering of the second telescopic cylinder 112 with regard to the first telescopic cylinder 111 by rotating manually the crank in clockwise or in counterclockwise direction, respectively.
Note that alternatively, an electrical or pneumatical or hydraulical mechanism for raising or lowering the telescopic cylinders is possible, too. At the top of the second telescopic cylinder 112, a jib such as an arm is attached. The jib 12 is orientated substantially perpendicular to the two telescopic cylinders 111, 112. At the one end of the jib 12, the jib is mounted and attached to the second telescopic cylinder 112; at the other end of the jib 12, a balancing unit 13 is attached to the jib 12. Note, that the balancing unit is movably attached to the jib 12. This enables the user of the device 10 to vary and chose different positions of the balancing unit 13 with regard to the mast 11 of the device 10. Exemplarily, the balancing unit 13 is realized by a gas spring.
Figure 3 shows the same device 10 as illustrated in Figure 2; however, in a slightly different perspective. Again, the mast 11 with the two telescopic cylinders 111, 112 and the crank 113 can be discerned. Also, the jib 12 which is attached at its one end to the second telescopic cylinder 112 can be seen. The balancing unit 113 is movably attached to the jib 12. The direction of movement of the tool is referenced by reference sign 212. As the balancing unit 13 is moved along the direction 212, also the tool 21 which is supposed to be connected to the balancing unit 13 is arranged to be moved in the direction of 212.
Figure 3 furthermore illustrates the direction of movement of the jib 121. The jib 12 is raised or lowered in substantially vertical direction by means of a relative movement of the first telescopic cylinder 111 and the second telescopic cylinder 112.
Figure 4 shows the device 10 during operation, namely during tightening nuts in a tower of a wind turbine. Figure 4 shows two tower segments of a wind turbine, namely a first tower segment 23 and a second tower segment 24. These tower segments 23, 24 are held together, in other words assembled, by a plurality of fasteners. Each fastener comprises a bolt and a nut. Exemplarily, the number of fasteners which are necessary to assemble and connect both tower segments amounts up to one hundred.
Figure 4 shows the device 10 comprising the mast 11, the jib 12 and the balancing unit 13. The mast 11 is placed upon one of the nuts, namely the attachment nut 25. Note that the attachment nut 25 is not a nut which is designed differently than the other nuts, it is just a nut that has been chosen to be the one where the device 10 is attached to.
After attaching the device 10 via the mast 11 to the attachment nut 25, the heavy hydraulic torque wrench, or generally the tool 21, is connected to the balancing unit 13. This connection might be carried out by a simple hook. The balancing unit 13 might be realized by a standard gas spring, which is lightweight and powerful.
After connection of the balancing unit 13 with the tool 21, the telescopic cylinders 111, 112 are extended. As a consequence, the jib 12 is raised. This is done manually by rotating the mechanical crank 113 which is located at the bottom of the mast 11. The jib 12 is raised to such an extent that the tool 21 is sufficiently balanced. This means that the jib 12 is raised to such an extent that the virtual mass, that the person who is handling the tool 21 experiences, is significantly reduced. This might be for example the case when the mass of the tool 21 is reduced to an amount of less than five kilogram. Once the jib 12 is raised, the hydraulic torque wrench is activated and the first fastener 221 is tightened.
After having tightened the first fastener 221, the tool 21 is lifted slightly and shifted horizontally towards the mast 11 until reaching the second fastener 222. Lifting of the tool 21 is significantly facilitated as the tool 21 is balanced. Then the tool 21 is put into place for tightening the second fastener 222. Once the second fastener 222 is completely tightened, the tool 21 is lifted slightly again and shifted horizontally towards the mast until the third fastener 223 is reached. Subsequently, the tool 21 is lowered again slightly and the third fastener 223 is tightened by activating and operating the hydraulic torque wrench.
These steps are repeated for all nuts between the first fastener 221 and the attachment nut 25. Then, the jib 12 is lowered by turning the crank 113 until the full tension of the balancing unit 13 on the tool 21 is relieved. Then the mast 11 is detached from the attachment nut 25 and the mast 11 is lifted and moved to the next attachment nut. In this case, the next attachment nut would be around ten nuts to the left of the attachment nut 25 being illustrated in Figure 4.
Then the steps of attaching the mast 11 to the attachment nut, raising the jib 12, and tightening the fastener by means of a hydraulic torque wrench are repeated. These steps may be repeated until the whole tower flange is tightly connected to each other. Note that this is possible without lifting the heavy hydraulic torque wrench.
Finally note that the inventive concept in principle can well be transferred to other applications such as tightening fasteners at other areas in the wind turbine, for example the nacelle or the hub. Likewise, this inventive concept can also be applied outside the field of wind turbines.

Claims

Device (10) for handling a tool (21) for tightening a fastener,
wherein
- the device (10) is suitable to assist assembly of two components of a wind turbine,

- the device (10) comprises a mast (11), a jib (12) and a balancing unit (13),

- the balancing unit (13) is attached at the jib (12),

- the balancing unit (13) is arranged and prepared to be connected to the tool (21), and

- the balancing unit (13) is arranged and prepared to counteract at least partially the weight of the tool (21), characterized in that
the mast (11) comprises means for raising and lowering the jib (12).
Device (10) according to claim 1,
wherein the balancing unit (13) is movably attached at the jib (12).
Device (10) according to one of the preceding claims,
wherein the tool (21) has a mass exceeding an ergonomic limit for manual handling of tools.
Device (10) according to one of the preceding claims,
wherein the tool (21) is a torque wrench, in particular a hydraulic torque wrench.
Device (10) according to one of the preceding claims,
wherein the means for raising and lowering the jib (12) comprise at least two telescopic cylinders nested within each other.
Device (10) according to one of the preceding claims,
wherein the fastener is a nut.
Device (10) according to one of the preceding claims,
wherein the balancing unit (13) is a spring, in particular a gas spring.
Device (10) according to one of the preceding claims, wherein the components of the wind turbine to be assembled are tower segments of the wind turbine.
Device (10) according to one of the preceding claims,
wherein the balancing unit (13) is arranged and prepared to counteract the weight of the tool (21) such that the resulting force in parallel to the gravitational force of the tool (21) is less than fifty Newton.
Method of tightening a first fastener (221) for assembling a first component of a wind turbine with a second component of the wind turbine and at least a second fastener (222) for assembling the first component with the second component,
wherein the method comprises the steps of
- attaching a device (10) for handling a tool (21) for tightening a fastener to a first section of the first component, wherein the device (10) comprises a mast (11), a jib (12) and a balancing unit (13), and wherein the mast (11) comprises means for raising and lowering the jib (12),

- placing the tool (21) at the first fastener (221) to be tightened,

- connecting the tool (21) with the balancing unit (13),

- raising the jib (12) by means of the telescopic cylinders of the mast (11) such that the weight of the tool (21) is at least partially counteracted,

- tightening the first fastener (221) by means of the tool (21),

- moving the tool (21) along the jib (12) of the device (10),

- tightening the second fastener (222) by means of the tool (21), and

- lowering the jib (12) such that the tension on the balancing unit (13) is relieved.
Method according to claim 10,
wherein the method comprises the further step of, after tension on the balancing unit (13) has been relieved,
- detaching the device (10) from the first section,

- moving the device (10) from the first section to a second section, and

- attaching the device (10) at the second section.
Method according to one of the claims 10 or 11,
wherein the first section comprises a nut and/or a bolt.
Method according to claim 12,
wherein the device (10) is attached at the head of the nut or bolt at the first section of the first component.
Method according to one of the claims 10 to 13,
wherein raising and lowering of the jib (12) is carried out manually.
Method according to one of the claims 10 to 14,
wherein the mast (11) is directed substantially vertically and/or the jib (12) is directed substantially horizontally during carrying out of the method.