LIFTING ARRANGEMENT FOR A MAST, A MAST DIVIDED INTO ELEMENTS, AND METHODS FOR ASSEMBLING, DISMANTLING AND SERVICING OF A MAST

Abstract

 A lifting arrangement for the assembling, dismantling or servicing of a mast (2) divided into elements (1). The lifting arrangement comprises:
- an engagement member (5) in parts arranged to be fixed to the mast elements in their longitudinal direction, and with the parts aligned with each other,
- a lifting device (6) with a platform (7) for the transport of objects along the mast,
- wherein the lifting device (6) further comprises a driving mechanism (9) which can lift the lifting device (6) while engaging the engagement member (5) whereby the lifting device (6), in an assembled state, without interruption can travel along the mast (2) while the mast elements (1) are acting as a support as well as a carrier of the engagement member (5) and the lifting device (6) travelling thereupon,
- wherein the lifting device (6) is arranged to, in an assembled state, extend from one side of the mast (2) only and leave the remaining sides of the mast (6) free. The invention also concerns a mast (2) divided into elements (1) and methods for assembling, dismantling and servicing of a mast.

Description

Field of the invention

[0001] The invention concerns a lifting arrangement to be applied to a mast. The invention also concerns a mast divided into elements, and methods for assembling, dismantling and servicing of a mast.

Background of the invention

[0002] Mast for wind measurements are erected in connection to locations for planned wind power stations. The results from the measurements will be the basis for a decision on establishment. They are also used to verify the performance of the wind power stations. In step with the power stations being built ever taller, the measurements must also be done at greater heights. Nowadays, measurements are demanded for heights of 150 - 200 meters. When the measurements are finished, often after 1 - 2 years, the masts remain for verification of the performance of the wind power stations, or they are dismantled and moved to another location.

[0003] The erection of masts in the present height are almost without exception done with the help of a helicopter. Even though the masts are slim by construction, in order to not to disturb the air flow at the recording devices, the individual elements will be so heavy that a significant amount of lifts are required. The erection is dependent on good weather conditions with low and steady winds and good visibility. Equally favourable conditions are required during dismantling. During the use of the mast, servicing of the mast or the instruments that are attached to it may be necessary, and therefore, service staff must be able to climb the mast on a ladder attached to the mast. A high mast can, according to this document, be considered to be a mast which is requiring guys to be securely erect in any weather. Generally, depending on the construction, such masts are higher than 100 meters.

[0004] As an alternative to assembling masts with the use of a helicopter, a method for assembling a mast and a kit-of-parts for the execution of the method is known from the document SE 392 312. This method is not, however, suited for high masts since it comprises lifting mast elements in a steel rope, see for instance said document, figure 16. At great heights, the lift is difficult to manage due to, among other things, that the mast element is bulky, has a high dead weight and constitutes a considerable surface exposed to the wind.

[0005] US 3 354 599 discloses a method to bring a lifting arrangement up a mast. Also in this document, the lifting arrangement is using a steel rope to elevate people or materials up the mast.

[0006] US 6 357 549 discloses a method and a device to erect a tower and to do maintenance on the tower. The document discloses a platform 10 that is surrounding a hollow tower 72 (figure 5, view from above). The platform can climb up and down the tower and carry a load, such as a new tower element. It is evident from this document, in column 20, rows 62-67 that the device is not useful for buildings that comprise guys, such as high masts. For this reason, US 6 357 549 is only applicable to free-standing structures without guys (towers). The lifting arrangement in US 6 357 549 is climbing a rail resting on the ground (see column 2, rows 40 - 42), which is making it relatively heavy and therefore also more expensive.

Summary of the Invention

[0007] It is thus an object of the invention to solve or reduce the problems mentioned above and provide an improved device/method to erect, dismantle and service high masts.

[0008] The solution is provided with a device in the form of a lifting arrangement for the assembly, dismantling or servicing of a mast divided into elements according to claim 1.

[0009] Since the lifting device in an assembled state extends from one side of the mast only and leaves the remaining sides of the mast free, the lifting device is able to carry new elements up the mast during its erection without being impeded by guys, which may protrude from the corners of the mast and other sides.

[0010] By way of this lifting arrangement, assembling and dismantling of the mast in a more secure way is facilitated, independent of weather and visibility conditions while engaging less people. The cost of assembling / dismantling of the mast is substantially reduced for these reasons in comparison with the traditional assembly / dismantling with a helicopter. Moreover, if desired, the installers can be spared the time and energy consuming climbing the mast by themselves following along with the lifting device up the mast. Assembly and servicing of equipment can be effected more simply.

[0011] The mast elements are acting as a support as well as a carrier for the engagement member which the lifting device travelling thereupon is using. In this way, a separate carrying device, such as for instance the one that is used in US 6 357 549, is avoided.

[0012] Since the lifting device is climbing on the mast, the need for the lengthy lifting ropes disappears, said lifting ropes having a high weight, are bulky and constitute a substantial surface exposed to the wind.

[0013] The solution is also provided with a mast and methods for assembling, dismantling and servicing of a mast according to claims 7, 8, 9 and 10. These have advantages corresponding to those for the lifting arrangement.

[0014] The dependent claims disclose additional advantageous embodiments of the invention.

Brief Description of Drawings

[0015] The invention will now be described with reference to the drawings on which Fig. 1 discloses a mast element,

Fig. 2 discloses two mast elements assembled onto a base,

Fig. 3 discloses a cage attached onto the mast elements,

Fig. 4 discloses a mast element for assembly, placed onto the roof of the cage,

Fig. 5 discloses a position where the cage has been brought up to the upper part of the mast.

Detailed description of embodiments

Lifting arrangement

[0016] According to the invention a lifting arrangement for the assembly, dismantling or servicing of a mast 2 divided into elements 1 is provided, which mast can be provided with guys.

[0017] Fig. 1 discloses an example of such an element 1 for a mast. Depending on the construction of the mast, the elements can be differently designed, but each element 1 comprises at least three, parallel, in use substantially vertical rods 3, which rods 3 mutually are fixed by a plurality of members in a truss construction 4 and together enclose a volume. The elements typically have a height of a couple of metres.

[0018] When the mast is erected, the elements 1 are connected with each other in their longitudinal direction to form the mast 2, see for instance fig. 2 that discloses an early stage with two erected, with each other connected elements 1.

[0019] The lifting arrangement itself comprises an engagement member 5 in parts, which parts are arranged to be fixed to the mast elements in their longitudinal direction and are arranged to be aligned with each other, see for instance figure 2, where two parts of an engagement member 5 of each mast element 1 are aligned with each other.

[0020] The lifting arrangement is further comprising a lifting device 6 with a platform 7 for the transport of objects along the mast, e.g. a new element 8 of the mast 2 that is going to be assembled to such elements 1 that are already assembled, see Fig. 4.

[0021] To enable the lifting device 6 to travel along the mast, it comprises a driving mechanism 9 which can propel the lifting device 6 while engaging the engagement member 5 whereby the lifting device 6, in an assembled state, without interruption can travel along the mast 2 while the mast elements 1 are acting as a support as well as a carrier of the engagement member 5 and the lifting device 6 travelling thereupon with any load. Owing to that it is the mast elements 1 that are carrying the engagement member and the lifting device, the engagement member can be made relatively weak and weight is therefore saved in the construction. In the figures, the driving mechanism 9 is shown integrated in the lower part of the lifting device.

[0022] The engagement member 5 is providing two functions, namely guidance of the lifting device 6 and a structure in which the lifting device 6 can engage and along which it can climb. The engagement member 5 can be provided in one and the same physical part, such as, for instance, a pinion rack. The cogs are providing the structure into which the lifting device can engage and climb along, while the cross section of the rack, for instance circular, brings about, together with a corresponding surrounding mechanism of the lifting device, the necessary guidance.

[0023] The two functions of the engagement member can also be provided in two separate physical units, for instance tracks with rollers for the guidance and a separate pinion rack that is providing the structure along which the lifting device 6 can climb. Different structures for the climbing can be used, for instance the already mentioned pinion rack or a threaded rod. If it is a pinion rack, there have to be members for the adjustment of two pinion racks that meet in order to account for tolerances in the mast elements.

[0024] The lifting device 6 is arranged to, in an assembled state engaging the engagement member 5, occupy one side of the mast 2 only and leave the remaining sides of the mast 2 free. The other sides of the mast are thereby free to be attached to the guys, which enable building a high mast since such masts require staying in order to be securely erect in any weather.

[0025] To simplify the drawings, no guys are shown on these, but it is apparent that the lifting device extends from one side of the mast only, and therefore guys can be applied onto the remaining sides and corners of the mast.

[0026] According to one embodiment of the mast, the lifting device 6 can comprise a cage 10, arranged for the transport of people, see Figure 3.

[0027] The cage 10 enables safe transport of people and can for instance accommodate a service engineer that is protected from falling from the cage and also from falling objects during assembly work and ice falling from the mast, for instance during servicing. This is especially important in connection to high masts where service staff are particularly vulnerable. It is also tiring to climb long stretches on a ladder in such masts. After a longer climbing stretch, often with materials and tools that have to be brought along, an installer or service person can be exhausted and thus be exposed to an increased risk of accident.

[0028] It should be noted that on all the drawings, the lifting device 6 is only shown in its embodiment as a cage, but other variants are of course possible.

[0029] According to a variant of the cage 10, its roof constitutes the platform 7. The lifting device 6 is formed such that it, in use and in the vicinity of an upper end of a mast element 1, on which it is climbing, has a position in which the platform 6 extends on a level with the upper end of the previously assembled mast element.

[0030] See for instance figure 5 where the lifting device 6 has been placed at the upper end of the mast element that has already been assembled at the top of the mast. The platform 7 of the lifting device 6 is on a level with the upper end of this mast element.

[0031] The lifting device 6 can further comprise a transfer device 11 arranged to transfer an object loaded on the platform, e.g. a mast element 8 (Figure 4), generally in a horizontal direction from the platform to a position above a previously assembled mast element.

[0032] Thus, a new mast element 8 that is being carried upwards does consequently not have to be lifted from the platform over to its space on top of the mast, but can substantially just be pushed sideways to come to be placed on top of the previous element.

[0033] When the mast element, that is to be assembled, has been pushed sideways and is located above the mast to which it will be connected, the lifting device can be lowered somewhat until the element makes contact with the mast. The lifting device, therefore, does not have to be equipped with a separate device, for instance a hoisting crane, in order to transfer a new mast element from the platform to its location in the mast.

[0034] In Figure 3, a variant of the transfer device 11 is shown. It comprises two pairs of two parallel rods 12, each in one end articulatedly attached to a stiff member 13 and each in its other end articulatedly attached in relation to the lifting device 6. Each pair is located on the side of the mast element that is to be transferred. Further, this transfer device 11 comprises a linear drive unit 14 connected between the parallel rods 12. Due to this construction, a load can be attached in the stiff member 13 and by activation of the linear drive unit 14, the transfer device 11 can be brought to lift the load somewhat in a vertical direction during simultaneous transfer in a horizontal direction. The linear drive unit 14 can for instance be a hydraulic cylinder or a ball screw.

[0035] This movement can be studied by comparing this variant of the transfer device in Figures 4 and 5.

[0036] At a great height, this embodiment of the transfer device 11 constitutes a more simple, safer and more robust construction compared to a hoisting crane.

[0037] Another variant of the transfer device, not shown in the figures, can comprise a member that is arranged to expand telescopically in a horizontal direction to bring about a horizontal transfer of an object loaded on the platform, e.g. a mast element, from the platform to a position above a previously assembled mast element.

[0038] In these ways, no lifting of the mast element from the platform is required. It only has to be assured that the members for the horizontal transfer escape the mast when the lifting device is brought down from its upper position to the original position after delivery of said mast element.

[0039] In the figures 4 and 5 it is hinted at that the mast element is hanging in wires from the member 13. As an alternative, the transfer device can be equipped with members that grasp the mast, in the version of the mast element that is shown, for instance in the cross, ¼ of the height of the element from above. The transfer device is then naturally made lower in order to fit. In view of a telescopic transfer device, one can for instance get hold of the frame legs 3 close to the lower part of the element. The holding movement can be activated from the cage or via a remote control in the same way as the other transfers.

[0040] In order to propel the lifting device 6, the driving mechanism 9 of the mast according to any, embodiment described above, also suitably comprises a motor and an energy source belonging to it.

[0041] In this way, autonomous drive of the driving mechanism is facilitated and, therefore, the need for, for instance, a long and heavy electric cable that has to travel up and down the mast as the lifting device is moving, disappears. Such an electric cable is particularly troublesome when the mast is high.

[0042] An embodiment of said motor and driving source for autonomous drive comprises an electric motor with regenerative capacity and the energy source an electric battery. In this way, the potential energy of the lifting device can be recovered on its way down and be stored in the battery.

[0043] The regenerative capacity of the motor can arise from the windings of the motor as such or from a separate part with its own windings solely intended for the regeneration of electric energy.

[0044] In order to manage the assembly of all mast elements, which can be something in the neighbourhood of one hundred for a high mast, it is conceivable to use a relatively large, fully charged battery. It affords great freedom of action since assembly can be effected in places without access to electric energy through a grid or electric generator.

[0045] Another alternative is to quick charge the battery when the lifting device has returned to ground position and while the next mast element is being loaded (when assembling the mast). That, however, requires access to an electric grid or electric generator.

[0046] When solely dismantling the mast, a significantly smaller battery is required, since potential energy of the existing mast elements continuously is recovered on their way down.

[0047] As a variant, the driving mechanism can constitute a combination of an electric motor with a battery and a combustion engine with a fuel tank and thereby constitute a hybrid drive.

[0048] According to this variant, the electric motor is arranged to be driven by the battery and the combustion engine is arranged to drive the electric motor in a regenerative mode in order to charge the battery.

[0049] An advantage with this arrangement is that the size and cost of the battery can be reduced while at the same time keeping the regenerative drive.

[0050] The lifting arrangement, or parts of it, does not have to remain attached to a mast but can be moved to another location if it is not considered to be needed for servicing. Should one want to dismantle the mast, the lifting arrangement could be put back on.

Mast

[0051] When the lifting arrangement according to the invention has been assembled to a number of mast elements and the mast elements have been assembled together, they form a mast divided into elements according to the invention.

[0052] Thus, such a mast comprises a plurality of elements 1 which comprise at least three, parallel, in use substantially vertical rods 3, which rods 3 mutually are fixed by a plurality of members in a truss construction 4 and together enclose a volume, wherein the elements 1 are connected together in their longitudinal direction to form the mast 2.

[0053] The mast comprises further a lifting arrangement according to any of the embodiments of the lifting arrangement according to the invention that were previously described.

[0054] As the base version, the mast thus comprises an engagement member 5 in parts fixed to the mast elements in their longitudinal direction and aligned with each other.

[0055] Further, it also comprises a lifting device 6 with a platform 7 for the transport of objects along the mast, e.g. a new element 8 of the mast 2 that is going to be assembled to such elements 1 that are already assembled.

[0056] The lifting device 6 comprises a driving mechanism 9 which can elevate the lifting device 6 while engaging the engagement member 5 whereby the lifting device 6 without interruption can travel along the mast 2 while the mast elements 1 are acting as a support as well as a carrier of the engagement member 5 and the lifting device 6 travelling thereupon. The lifting device 6 is assembled with and is engaging the engagement member 5 and extends from one side of the mast 2 only and leaves the remaining sides of the mast 2 free.

[0057] The mast according to the invention can, as mentioned, be provided in different embodiments corresponding to any embodiment of the above described embodiments of the lifting arrangement according to the invention. For instance, the lifting device of the mast can be provided with a cage that enables transport of people.

[0058] The advantages that have been mentioned above in connection with the description of the different embodiments of the lifting arrangement according to the invention are directly corresponding to those corresponding embodiments of the mast according to the invention.

Methods according to the invention

Method for assembly of a mast divided into elements

[0059] The invention also concerns a method for assembly of a mast divided into elements, and will be described with reference to the figures.

[0060] The method comprises using a lifting arrangement according to any of the embodiments described above. Before the mast is assembled, the parts of the engagement member 5 shall be fixed to the elements of the mast in their longitudinal direction. This can happen before the assembly occasion or in connection with the assembly of the mast.

[0061] The method is divided into a number of steps that have been numbered. Comments to each step is provided in parenthesis. The mast is assembled by the method comprising to:

1) assemble an element 1 of the mast to a base 15 on the ground, this element designated the base element 16.
(See for instance figure 2. The element can be erected with for instance a wheel-loader.)

2) Optionally assemble at least one further element 1 on the base element, wherein the parts of the engagement member 5 on the elements are aligned with each other in such a way that the lifting device 6, without interruption, can travel along the assembled elements 1, wherein the assembled elements, when existing, together constitute the base element 16.
(See for instance figure 3, where two elements constitute the base element.)

3) apply the lifting device 6 onto the base element 16 such that lifting device 6 engages the engagement member 5 of the base element.
(See figure 3 where the lifting device has been attached to the base element 16.)

4) Load, onto the lifting device 6, an assembly element 8, which is a new element 8 to be assembled onto the last assembled element 1 of the mast 2.
(See figure 4. Loading of the assembly element can happen with for instance a wheel-loader or other suitable machine if the lifting device comprises a cage with a roof as a platform, such as in figure 4. If the lifting device comprises an extra device for lifting a load on the platform, such as a crane, this can be used.)

5) lift the assembly element 8 with the lifting device 6 by the lifting device climbing along previously already assembled element(s) 1 while engaging the engagement member 5.
(See figure 5: the lifting device 6 climbs along the already assembled elements 1 by 'bracing itself against the engagement member 5 (fig. 4).)

6) upon arrival of the lifting device 6 with the assembly element 8 at the uppermost already assembled element 1: unload the assembly element 8 from the lifting device 6.
(See figure 5: the lifting device 6 has reached the presently uppermost, already assembled element and unloads the assembly element 8 from the platform 7 of the lifting device 6. In the figure, a transfer device that can move the assembly element 8 to its place above the last assembled element by activation with a linear drive unit, for instance a hydraulic cylinder or a ball screw, is used.)

7) assemble the assembly element 8 at the already assembled element 1, wherein the longitudinal part of the engagement member 5 of the assembly element 8 is aligned with the part of the engagement member 5 at the already assembled element 1 in such a way that the lifting device 6 without interruption can travel from the previously already assembled element 1 further along the now, at this element 1, assembled assembly element 8.
(At this step, the assembly element 8 is fitted to the already assembled element, in such a way that the parts of the engagement member are aligned.)

8) bring back the lifting device 6 to ground position by the base element by letting it travel down along the assembled elements while engaging the engagement member 5.

9) repeat items 4) through 8) until all elements 1 of the mast 2 are assembled, wherein the method is carried out while the lifting device 6 is extending from one side of the mast 2 only and is leaving the remaining sides of the mast 2 free.

[0062] In case the mast includes guys, then these can be assembled with the help of the lifting device according to a variant of the method. When the mast has been assembled up to the height where guys should be attached, the guy wires can be connected to the lifting device, be lifted to the height where they are to be placed, and thereafter transferred to and connected to the mast.

[0063] The method is applicable to any of the embodiments of the lifting arrangement that have been described above (which in turn have a correspondence to any of the embodiments of the mast according to the invention, as has been mentioned previously). Therefore, the method also comprises any modification that comprises any such embodiment of the lifting arrangement.

[0064] It can be mentioned, as an example, that the variant of the lifting arrangement according to the invention where the lifting arrangement comprises an electric motor with an associated battery has a corresponding embodiment in the method for assembly of the mast where step 5) and step 8) are modified such that the climbing is effected by the lifting device being propelled by the electric motor which is fed by the battery.

[0065] Remaining variants of the method for assembly of the mast corresponding to the different embodiments of the lifting arrangement according to the invention are not described here to save space, but can with the help of this text be realised by the skilled person and is incorporated into the subject matter that is disclosed herein.

Method for dismantling a mast divided into elements

[0066] The invention also comprises a method for dismantling a mast divided into elements. This method has its starting point in the above described mast according to the invention and states how such a mast can be dismantled. The method is applicable to any of the embodiments of the mast that can occur by the mast being implemented by any embodiment of the lifting arrangement according to the invention as described previously.

[0067] The mast 2 is dismantled by the method comprising to:

1) let the lifting device 6 climb to the topmost but one mast element 1 with the platform 7 on a level with the top most element.
(The lifting device climbs without a load to the top of the mast in order to prepare unloading / dismantling of the top most element.)

2) dismantle said top most mast element from the mast and transfer it to the platform.
(The mast element is detached from its anchoring to the element that is situated below it and is transferred to the lifting device with a transfer device or other suitable means).

3) let the lifting device climb down to ground level with the dismantled element and, at that level, let it be lifted off from the lifting device.
(The dismantled element can, as a suggestion, be lifted from the lifting device with a heavy equipment or other suitable means.)

4) repeat steps 1-3 until the mast is dismantled.

[0068] This method enables a simple and cost effective way to dismantle a mast.

[0069] Since the method is, as has been mentioned previously, applicable to a mast formed from a lifting arrangement according to any of the embodiments of this lifting arrangement according to the invention as described previously, the method comprises also any modification that comprises any such embodiment of the lifting arrangement.

[0070] It can be mentioned, as an example, that the variant of the lifting arrangement according to the invention where the lifting arrangement comprises an electric motor with an associated battery has a corresponding embodiment in the method for assembly of the mast where step 1) and step 3) are modified such that the climbing is effected by the lifting device being propelled by the electric motor which is fed by the battery.

[0071] Remaining variants of the method for dismantling of the mast corresponding to the different embodiments of the mast modified according to the different variants of the lifting arrangement according to the invention are not described here to save space, but can with the help of this text be realised by the skilled person and is incorporated into the subject matter that is disclosed herein.

Method for service of a mast divided into elements

[0072] Finally, the present invention also comprises a method for servicing a mast divided into elements.

[0073] This method has, exactly as the method for dismantling of a mast, it starting point in the above described mast according to the invention and states how such a mast can be serviced.

[0074] The mast can be serviced by the method comprising to:

1) take on board service staff on the lifting device 6,

2) let the lifting device 6 with the service staff climb to the level of the mast where servicing is required,

3) carry out servicing.

[0075] The method affords an improved opportunity to service compared to the service staff having to climb on their own accord on a ladder. It is less tiring to use the lifting device for lifting and more equipment can be brought along to the part of the mast that is to be serviced.

[0076] In the same way as the method for dismantling of a mast, the method for service of a mast comprises a number of different embodiments essentially dependent on which embodiment of the previously described lifting device of the invention that is used.

[0077] To save space, these embodiments are not described here, but can with the help of this text be realised by the skilled person and is incorporated into the subject matter that is disclosed herein.

Reference numerals

[0078] 

1.

Mast element

2.

Mast

3.

Rod / frame leg of mast

4.

Member / brace in a truss construction

5.

Engagement member

6.

Lifting device

7.

Platform

8.

Element to be assembled

9.

Driving mechanism

10.

Cage

11.

Transfer device

12.

Rods of transfer device

13.

Stiff member of transfer device

14.

Linear drive unit of transfer device

15.

Base

16.

Base element

Claims

1. Lifting arrangement for assembling, dismantling or servicing of a mast (2) divided into elements (1), wherein each element (1) comprises at least three, parallel, in use substantially vertical rods (3), which rods (3) mutually are fixed by a plurality of members in a truss construction (4) and enclose together a volume and can be connected together in their longitudinal direction to form the mast (2), wherein the lifting arrangement comprises:

- an engagement member (5) in parts, which parts are arranged to be fixed to the mast elements in their longitudinal direction and are arranged to be aligned with each other,

- a lifting device (6) with a platform (7) for the transport of objects along the mast, e.g. a new element (8) of the mast (2) that is going to be assembled to such elements (1) that are already assembled,

- wherein the lifting device (6) comprises a driving mechanism (9) which can propel the lifting device (6) while engaging the engagement member (5) whereby the lifting device (6), in an assembled state, without interruption can travel along the mast (2) while the mast elements (1) are acting as a support as well as a carrier of the engagement member (5) and the lifting device (6) travelling thereupon,

- wherein the lifting device (6) is arranged to, in an assembled state engaging the engagement member (5), extend from one side of the mast (2) only and leave the remaining sides of the mast (2) free.

2. Lifting arrangement according to claim 1, wherein the lifting device (6) comprises a cage (10), arranged for the transport of people.

3. Lifting arrangement according to claim 2, wherein the roof of the cage (10) constitutes the platform (7) and the lifting device (6) is formed such that it, in use and in the vicinity of an upper end of a mast element (1), on which it is climbing, has a position in which the platform (7) extends on a level with the upper end of that mast element, wherein the lifting device (6) further comprises a transfer device (11) arranged to transfer an object loaded on the platform, e.g. a mast element (1), generally in a horizontal direction from the platform to above a previously assembled mast element.

4. Lifting arrangement according to claim 3, wherein the transfer device (11) comprises two pairs of two parallel rods (12) each in one end articulatedly attached to a stiff member (13) and each in another end articulatedly attached in relation to the lifting device (6), wherein the transfer device (11) further comprises a linear drive unit (14) connected between the parallel rods (12), wherein a load can be attached in the stiff member (13) and the transfer device (11) is thereby arranged to, at activation of the linear drive unit (14), be brought to lift the load somewhat in a vertical direction during simultaneous transfer in a horizontal direction.

5. Lifting arrangement according to claim 3, wherein the transfer device (11) comprises a telescopic member which is arranged to expand telescopically in a horizontal direction to bring about a horizontal transfer of an object loaded on the platform (7), e.g. a mast element (8), from the platform (7) to above a previously assembled mast element.

6. Lifting arrangement according to any of claims 1-5, wherein the driving mechanism (9) comprises a motor and an energy source belonging to it, to facilitate autonomous drive of the driving mechanism.

7. Mast (2) divided into elements (1), wherein the mast comprises:

- a plurality of elements (1), into which the mast is divided, wherein each element (1) comprises at least three, parallel, in use substantially vertical rods (3), which rods (3) mutually are fixed by a plurality of members in a truss construction (4) and enclose together a volume, wherein the elements (1) are connected together in their longitudinal direction to form the mast (2),

- a lifting arrangement according to any of claims 1-6,

- wherein the parts of the engagement member (5) are fixed to the elements (1) in their longitudinal direction, and with the parts aligned with each other,

- wherein the lifting device (6) is assembled and is engaging the engagement member (5),

- wherein the lifting device (6) extends from one side of the mast (2) only and leave the remaining sides of the mast (6) free.

8. Method for assembly of a mast (2) divided into elements (1), wherein the method comprises using a lifting arrangement according to any of claims 1-6, wherein the parts of the engagement member (5) are fixed to the elements (1) in their longitudinal direction, wherein the mast (2) is assembled by the method comprising to:

1) assemble an element (1) of the mast to a base (15) on the ground, this element designated the base element (16),

2) optionally assemble at least one further element (1) on the base element, wherein the parts of the engagement member (5) on the elements are aligned with each other in such a way that the lifting device (6), without interruption, can travel along the assembled elements (1), wherein the assembled elements, when existing, together constitute the base element (16),

3) apply the lifting device (6) onto the base element (16) such that lifting device (6) engages the engagement member (5) of the base element,

4) load onto the lifting device (6), an assembly element (8), which is a new element (8) to be assembled onto the last assembled element (1) of the mast (2),

5) lift the assembly element (8) with the lifting device (6) by the lifting device climbing along previously already assembled element(s) (1) while engaging the engagement member (5),

6) upon arrival of the lifting device (6) with the assembly element (8) at the uppermost already assembled element (1): unload the assembly element (8) from the lifting device (6),

7) assemble the assembly element (8) at the already assembled element (1), wherein the longitudinal part of the engagement member (5) of the assembly element (8) is aligned with the part of the engagement member (5) at the already assembled element (1) in such a way that the lifting device (6) without interruption can travel from the previously already assembled element (1) further along the now, at this element (1), assembled assembly element (8),

8) bring back the lifting device (6) to ground position by the base element by letting it travel down along the assembled elements while engaging the engagement member (5),

9) repeat items 4) through 8) until all elements (1) of the mast (2) are assembled, wherein the method is carried out while the lifting device (6) is extending from one side of the mast (2) only and is leaving the remaining sides of the mast (2) free.

9. Method for dismantling a mast (2) divided into elements (1),the mast (2) having guys, wherein the mast is a mast according to claim 7, wherein the mast (2) is dismantled by the method comprising to:

1) let the lifting device (6) climb to the topmost but one mast element (1) with the platform (7) on a level with the top most element,

2) dismantle said top most mast element from the mast and transfer it to the platform,

3) let the lifting device climb down to ground level with the dismantled element and, at that level, let it be lifted off from the lifting device,

4) repeat steps 1-3 until the mast is dismantled.

10. Method for servicing of a mast (2) divided into elements (1), wherein the mast is a mast according to claim 7, wherein the method comprises to:

1) take on board service staff on the lifting device,

2) let the lifting device (6) with the service staff climb to the level of the mast where servicing is required,

3) carry out servicing.

Drawing