SE1550440A1

SE1550440A1 - A crane unit for hoisting facade elements

Info

Publication number: SE1550440A1
Application number: SE1550440A
Authority: SE
Inventors: Falk Henrik; Augustinson David; SANDSTRÖM Peter
Original assignee: Brunkeberg Systems Ab
Priority date: 2015-04-13
Filing date: 2015-04-13
Publication date: 2016-10-14
Also published as: SE542667C2

Abstract

. A crane unit (1) for hoisting facade elements comprising:. -a rectangular base plate (11) having a front short side (12), a rear short side (13) and opposing long sides (14, 15) and upper and lower support surfaces (16, 17), wherein the upper support surface (16) comprises; - a T-shaped crane mast (30), comprising a vertical boom (31) attached to the centre of an upper horizontal boom (34) and two pulleys (37, 38) arranged in each end of the horizontal boom for guiding a winch wire (39); - a winch unit (40) for winching a winch wire (39) comprising first and second drive discs (41, 42) and a winch wire storage reeler (45);. - a control unit (50) for controlling the winch unit (40); wherein. the T-shaped crane mast (30) is arranged adjacent the front short side (12) of the base plate (11) with the horizontal boom (34) aligned parallel with the long sides (14, 15) of the base plate (11) and wherein the winch unit (40) is arranged adjacent the rear short side (13) of the base plate (11) and wherein,. the lower support surface (17) of the base plate (11) comprises two parallel tracks (20, 21) of predetermined height, length and width for receiving forks of a pallet lifter.Figure 2

Description

A crane unit for hoisting façade elements Technical ﬁeld The present disclosure relates to crane for hoisting façade elements.

Background art Multi-storey buildings can be constructed in a variety of ways. Common to all multi-storey buildings, however, is a façade element. The façade element can be constructedto constitute an integral part of the building as a load bearing component or it may onlyserve as a weather protective layer. There may of course also be different combinationsof façade elements with load bearing properties and weather protective layers. If thefaçade element only is used as a weather protective layer to seal the building then it isusually formed as a plate. In such a case the multi-storey building comprises a buildingstructure onto which the plate forrned façade elements are attached.

It is common that the façade elements arrive at the working site on pallets. These palletsare then off-loaded by a tower crane, a mobile crane, a site hoist or the like and lifted tothe ﬂoor of the multi-storey building on which they are to be installed. This step oflifting and installing façade elements is one of the most time consuming tasks when anew multi-storey building is built. Thus, by reducing this time it is possible to reducethe overall time it takes to complete the whole multi-storey building. A furtherdrawback of the conventional construction method is that handling and storage of thefaçade elements occupies space on the construction site. Moreover, unloading, transporting and installation of the façade panels demands a lot of manual labor Brunkeberg Systems AB has developed an efficient method for mounting façadeelements which substantially reduces the time to unload, lift and mount façade elementson a building structure of a multi-storey building. According to the method, which isdisclosed in WO2010070082, façade elements are transported on a conveyer directlyfrom a delivery truck to a multi-storey building. The façade elements are then hoistedby an elevator unit, i.e. a crane, whilst inserted in slots of guiding rails mounted on thebuilding structure, i.e. the vertical edges of the façade element will run in slots while hoisted. This will make the hoisting procedure less sensitive to weather conditions, such as Wind, since the façade elements run steadily in the slots. The guiding-rails aremounted on the building structure all the Way up to the ﬂoor that is beneath the ﬂoor tobe installed, i.e. With this method the façade elements are mounted from the bottom andup. When the façade elements have reached the floor on Which they are to be installedthey are pushed in a horizontal direction towards the building and attached appropriatelyto the building.

The façade elements are installed floor by floor throughout the building and aftercompleted installation of one façade element, the crane needs to be moved one step sideWays and brought into position for hoisting of the next façade element.

The hoisting crane shown in WO20100070081 comprises a front lifting boom forhoisting façade elements. To Withstand the forces during lifting, the lifting boom is ofheavy dimensions and secured to the rear of the crane by an angular support bracket.Due to this specific design it is further necessary to secure the hoisting crane to theabove roof With a strut during lifting and also to use special equipment to move the crane around the ﬂoor.

Although proven reliable, the hoisting crane of WO20l0007008l is heavy and difficultto maneuver and the procedure of moving the hoisting crane around the floor is bothcumbersome and time consuming and has a significant impact on the total installation time of the façade.

Thus, it is an object of the present disclosure to provide an improved crane for hoistingfaçade elements. In particular it is an object of the present disclosure to providelightWeight and compact a crane for hoisting façade elements With may be moved easilyfrom one position on a ﬂoor to another. A ﬁarther object of the present disclosure is toprovide a crane for hoisting façade elements Which may be moved by standard equipment.

Summary of the disclosureAccording to the disclosure at least one of the aforementioned objects is achieved by a crane unit l for hoisting façade elements comprising: -a rectangular base plate 11 having a front short side 12, a rear short side 13 andopposing long sides 14, 15 and upper and lower support surfaces 16, 17, wherein theupper support surface 16 comprises; - a T-shaped crane mast 30, comprising a vertical boom 31 attached to the centre of anupper horizontal boom 34 and two pulleys 37, 38 arranged in each end of the horizontalboom for guiding a winch wire 39; - a winch unit 40 for winching a winch wire 39 comprising first and second drive discs41, 42 and a winch wire storage reeler 45; - a control unit 50 for controlling the winch unit 40; wherein the T-shaped crane mast 30 is arranged adjacent the front short side 12 of the base plate11 with the horizontal boom 34 aligned parallel with the long sides 14, 15 of the baseplate 11 and wherein the winch unit 40 is arranged adjacent the rear short side 13 of thebase plate 11 and wherein, the lower support surface 17 of the base plate 11 comprises two parallel tracks 20, 21 of predeterrnined height, length and width for receiving forks of a pallet lifter.

The crane unit according to the disclosure relies on a combination of, on one hand, theprovision of parallel tracks for receiving the forks of a pallet truck on the base plate and,on the other hand, the careful arrangement of the components of the crane unit in viewof their weight. A particular advantage with the crane unit according to the disclosure isthat its compact design allows it to be realized in dimensions which make it possible to engage and maneuver the lifting crane with a commercially available pallet lifter.

In more detail, during a lifting operation with the crane unit according to the disclosure,the forces from a façade element and the reeled out winch wire, are essentially taken inperpendicular direction by the vertical boom of the T-shaped crane mast. The T-shapedcrane mast can therefore have a very light constructional design without any auxiliaryreinforcements. Due to this lightweight overall construction of the T-shaped crane mast,and its relatively short horizontal boom, the weight of the winch unit may constitutesubstantially the only counterweight of the crane. In fact, the winch unit may be placed rather close to the T-shaped mast and still provide a suff1cient counterweight. This in turn makes it possible to ﬁt the components of the crane unit on a base plate which is small enough to be lifted and maneuvered by a pallet lifter.

Further features and altematives of the lifting crane are disclosed in the following detailed description and the appended claims.

Brief description of the drawings Figure 1: A perspective view of a façade installing system, including a crane unitaccording to the disclosure.

Figure 2: A perspective left side view of the crane unit according to the disclosure.

Figure 3: A perspective right side view of the crane unit according to thedisclosure.

Figure 4: A perspective view from below of a first altemative of the base plate ofthe crane unit according to the disclosure.

Figure 5: A perspective view from below of a second altemative of the base platecrane unit according to the disclosure.

Figure 6: A perspective view from below of a third altemative of the base plate crane unit according to the disclosure.

Detailed description of the disclosure Figure 1 shows a building site of a multi-storey building 100 in which a mountingsystem 101 of the initially described art is employed. Guide profiles 102, also calledwind posts, are erected around the building from the ground up to the various ﬂoors ofthe building. A conveyor 103 is located outside the guide profiles. The conveyortransports façade element 105 from a storage (not shown) to the building 100. A liftingjig 104 is guided in the guide profiles 102 and is arranged to be moved by a crane 1 upand down from the conveyor 103 to a ﬂoor of the building. In operation, the lifting jig104 is lowered by the crane 1 to the level of the conveyor 103 to engages a façadeelement 105 hanging on the conveyor 103 and move it into the guide prof1les 102 so that the façade element can be hoisted up to a ﬂoor of the building and be installed.

The crane unit 1 according to the disclosure will in the following be described in detailwith reference to figures 2 and 3. Starting with figure 2, the crane unit 1 comprises abase plate 11, which may have any geometrical forrn, for example elongated rectangularform. The base plate 11 thereby comprises a front short side 12 a rear short side 13 andopposing first and second long sides 14, 15. Since figure 2 is a perspective side viewfrom the left only the rear short 13 side and the first long side 14 are visible. However,the front short side 12 and the second long side15 are shown in figure 3. The crane unit1 further comprises a T-shaped crane mast 30, a control unit 50 and a winch unit 40 which are arranged on the upper support surface 16 of the base plate 11.

Tuming to figure 3, which shows the crane unit 1 according to the disclosure in a frontside view. The T-shaped crane mast 30 comprises a vertical boom 31 which extendsvertically from the base plate 11. The vertical boom 31 may be any suitable elongatedelement, such as a beam of square cross-section. However, as shown in figure 3, thevertical boom 31 may comprise two beanis 32, 33, for example H-beams, which in oneend are attached at the long sides 14, 15 of the base plate 11 and extend upwards fromthe base plate 11 in an angle towards each other such that the other end of the twobeams 32, 33 meet over the center of the base plate. The two beams 32, 33 thereby forma triangular structure with the top point over the centre of the base plate 11. Thisstructure provides stability to the T-shaped mast and good distribution of the liftingweight onto the two beams. The vertical boom 31 is attached as close as possible to thefront short side 12 of the base plate 11 in order to minimize the length of the horizontalboom of the T-shaped mast. Preferably, the vertical boom 31 is attached at the frontshort side 12 of the base plate. The crane unit 1 further comprises two extendiblesupport legs 19, 18 to stabilize the crane unit from forces acting sideways. Theextendible support legs are arranged at the front short side 12 such that they may beextended perpendicular from the long sides 15, 16 of the base plate 11.

A horizontal boom 34 is attached at the top of the vertical boom 31 of the T-shapedcrane mast. The horizontal 34 boom is thereby attached to the vertical boom such that the horizontal boom is fixed to- and supported by the vertical boom. The vertical boom 31 is thereby attached to the centre of the horizontal boom 34 such that the horizontalboom is divided into a f1rst arrn 35 and a second arm 36 of equal lengths. The first arrn35 of the horizontal boom extends from the vertical boom 31 in direction towards thefront short side 12 of the base plate 11. The second arrn 36 of the horizontal boomextends from the vertical boom 31 in direction towards the rear short side 13 of the baseplate 11. Thus, the horizontal boom 34 extends parallel to the opposing long sides 14,15 of the rectangular base plate 11. A pulley 37, 38 is rotationally attached to the end ofeach arrn 35, 36 of the horizontal boom 34. In operation, the pulleys 37, 38 guide thewinch wire 39 and distribute the force of the lifting load such that it is applied onto thevertical boom 31. The arms 35, 36 of the horizontal boom are preferably short tominimize momentum. Preferably, the first arrn 35 extend approximately 30 cm out fromthe front short side 12 of the base plate 11 to perform the lifting operation. Thus, whenthe vertical boom 31 is attached at the front short side 12, each of the arms 35, 36 of the horizontal boom are 20 - 50 cm long, preferably, 25 - 35 cm long.

Next to the T-shaped crane mast 30, in direction from the front short side 12 towards therear short side of the base plate 11 is a control unit 50 arranged. In the figures 2 and 3the control unit 50 is enclosed by a housing 51 and comprises conventional electric andelectronic components for controlling the winch unit 40 during operation of the craneunit 1. To achieve a compact crane unit, the width of the housing 51 of the control unit,in direction from the front short side 12 towards the rear short side 13 of the base plate11, is equal to or less than the length of the arms 35, 36 of the horizontal boom 34.Thus, the second arrn 36 of the horizontal boom 34 extends over the housing 51 of thecontrol unit 50. The height of the housing 51 of the control unit 50 is less than theheight of the vertical boom 31 of the T-shaped crane mast 30. Thereby, the housing 51of the control unit 50 ﬁts underneath the horizontal boom 34 of the T-shaped crane mast 30.

The winch unit 40 is arranged next to the housing 51 of the control unit 50 in directionfrom the front short side 12 towards the rear short side 13 of the base plate 11. The winch units 40 comprises first and second drive discs 41, 42 which are arranged close to the end of the second arm 36 of the horizontal boom 34 of the T-shaped crane mast 30.Preferably, the first drive disc 41 is arranged such that the Winch Wire 39 from thesecond pulley 38 at the end of the second arm 36 of the horizontal boom 34 runsperpendicular from the second pulley 38 onto the first drive disc 41. A first motor andgear unit 43 and are arranged to the drive the first and second drive discs (see figure 2).The Winch unit 40 further comprises a Wire storage reeler 45. The Wire storage reeler 45is arranged between the drive discs 41, 42 and the rear short end 13 of the base plate 11.The Wire storage reeler 45 coils up the Winch Wire 39 on a drum during liftingoperations and feeds out the Winch Wire during loWering operation. A second motor andgear unit 46 (see figure 2) are arranged to drive the Wire storage reeler 45 during lifting or lowering operations.

In operation of the crane unit 1 the drive discs 41, 42 perforrns the pulling or loweringWork Whereas the Wire storage reeler 45 only coils or feeds the Winch Wire. Theadvantage thereof is that the feeding or pulling rate of the Winch Wire is the same overthe entire 1ifting or loWering operation. If the Wire reeler Would pull the Winch Wire during lifting, the pulling speed Would vary With the amount of Wire on the reel.

Thus, the Winch unit 40 extends from the rear short side 13 of the base plate 11 to thecontrol unit 50, i.e. the control unit housing 51. The control unit 50 extends from theWinch unit 40 to the vertical boom 31 of the T-shaped crane mast 30 and the vertical boom 31 extends from the control unit 40 to the front short side 12 of the base plate 11.

This particular arrangement and selection of components makes it possible to fit the T-shaped crane mast, the control unit and the Winching unit onto a rectangular base plateof such dimensions that the base plate may be lifted by a pallet truck. In the presentembodiment, the crane is designed to lift loads of approximately 1000 kg. Thecomponents of the crane unit are therefore dimensioned to fit on a rectangular base plate having a dimension of 2,2 x 0.8 m.

According to an aspect of the disclosure, the lower support surface 17 of the base plate11 comprises two parallel tracks 20, 21 for receiving the forks of a pallet lifter. Thetracks are forrned, i.e. delimited or defined, by at least three support elements which extend on the lower support surface of the base plate.

A pallet lifter (not shown in the drawings) is typically used to pick up and transportgoods on the ground. A pallet lifter is generally supported on wheels including asteerable rear wheel and two front wheels. The pallet lifter also comprise loadengagement means in the form of two forks for lifting pallets. The forks may be raisedor lowered to pick up or put down a load. In some embodiments, the forks of a palletlifter are supported on the front wheels. In other embodiments the pallet lifter the frontwheel are arranged on support arrns having wheels whereby the forks may be liftedindependently of the support arrns. Some embodiments of pallet lifters are manuallydriven by hand, e.g. pulled or pushed by a human operator. Other embodiments of palletlifters are propelled by for example by an electric motor. Examples of manual palletlifters are LHM230 or LHM300 available from the company Toyota Material Handling.Examples of propelled pallet lifters are LWE160 or LWE200 available from thecompany Toyota Materials Handling.

Figure 4 shows the lower support side 17 of the base plate ll of the crane unit 1 offigure 2 or 3 according to a first altemative. It is appreciated that in figure 4, the baseplate ll is tumed upside down with respect to its position in figure 2 and 3 in order to make the features of the lower support surface 17 more visible.

The lower support surface 17 comprises two parallel tracks 20, 21 of rectangular cross-section which extend parallel to each other from the rear short side 13 towards the frontshort side 12 of the support plate 11. The tracks extend parallel to the long sides 14, 15of the support plate 1 1.

In figure 4, the tracks extend over the entire lower support surface 17 of base plate ll, i.e. from the rear short side 13 to the front short side 12.

In figure 4, the tracks 20, 21 are formed by four support elements 22, 23, 24, 25, Whichare arranged on the lower support surface 17. A first and second support element 22, 23forms the first track 21 which extends along the first long side 14 of the base plate. Athird and fourth support element forms 24, 25 forms the second track 21, which extendsalong the second long side 15 of the base plate 11. The support elements may be wallsfor example formed by flat steel plates. The tracks are thereby channels, which aredelimited by the support elements 22, 23, 24, 25. Preferably, the first and secondsupport elements are formed by one U-shaped beam and the third and fourth supportelement are formed by a second U-shaped beam. When the crane unit 1 is placed on thefloor, the support elements 22, 23, 24, 25 are in contact with the ﬂoor and support thus the crane unit.

Figure 5 shows the lower support side 17 of the base plate 11 of the crane unit 1 of figure 2 or 3 according to a second altemative.

In figure 5, the tracks 20, 21 are formed by three support elements 22, 23, 24. A firstsupport element 22 extends over the lower support surface 17 along the first long side14 of the support plate 11. A second support element 23 extends over the lower supportsurface 17 along the second long side 15 (not shown) of the support plate 11. A third,central, support element 24 extends over the lower support surface 17 in the centre ofthe base plate, i.e. between the first and the second longitudinal support elements. Inthis case the first and second support elements are elongated plates and the third support element is a rectangular piece i.e. box which may be either hollow or solid.

In the altematives shown in figure 4 and 5, the support elements 22, 23, 24, 25 arecontinuous. This provides good stability and minimizes slipping when the crane unit is placed on the ﬂoor.

The support elements 22, 23, 24, 25 are spaced apart such that the tracks 20, 21 have asufficient width (W) to receive the forks of a pallet truck. The support elements 22, 23, 24, 25 are also sufficiently spaced apart so that the distance between the tracks 20, 21match the spacing of the forks of a pallet lifter. The height of the support elements 22,23, 24, 25, i.e. the distance the support elements protrude from the lower supportsurface 12 of the base plate 11 deterrnines the height (D) of the tracks 20, 21. The heightof the tracks is sufficiently dimensioned with regards to the thickness of the forks of the pallet lifter.

In the altematives shown in figure 4 and 5, the support elements 22, 23, 24, 25 and thetracks 20, 21 extend from the rear short side 12 to the front short side 13 of the baseplate 11. However, the tracks 20, 21 may also extend parallel to the front and rear shortside 12, 13 of the base plate and thus extend from one of the long sides 14, 15 of thebase plate 11 towards the other long side 14, 15. This facilitates sideway movement of the crane unit on the floor from one façade element installation position to another.

The tracks 20, 21 may have any length, under the condition that they are long enough toreceive a sufficient portion or the forks of a pallet lifter. The tracks may therefore extend over a portion of the base plate, or over the entire base plate.

The width of the forks of pallet lifters may of course vary between different models ofpallet lifters as do also the spacing between the forks of the pallet lifters. The distancebetween the tracks on the lower support side of the base plate as well as the height andwidth of the tracks must therefore be designed in advance to ﬁt the type of pallet lifter that is used at the building construction site in question.

A suitable range for the width of the tracks is 160 - 240 mm. A suitable range for theheight of the tracks is 50 - 110 mm. The tracks may be spaced apart by 140 - 200 mm.Preferably the parallel tracks on the lower support side of the base plate are designed inaccordance with the standard dimensions of tracks on so called Euro-Pallets (E-Pall).

The tracks of Euro pallets are approximately 230 mm wide and 100 mm deep. ll Figure 6 shows the lower support side 17 of the base plate 11 of the crane unit 1 offigure 2 or 3 according to a second alternative. It is appreciated that also in figure 6, thebase plate 11 is turned upside down in order to make the features of the lower support surface 12 more visible.

In figure 6, the support elements on the lower support surface 17 consists of discretesupport pieces 26, i.e. rectangular steel pieces, which are arranged space apart fromeach other. The discrete support pieces are arranged in three rows, a first row A ofsupport pieces 26 extend along the first long side 14 of the base plate 11, a second rowB of support pieces 26 extend along the second long side 15 of the base plate 11 andthird row C of support pieces 26 extend along the centre of the base plate 11. Asdescribed in the embodiment of figure 4 or 5, the dimensions of the discrete supportpieces are selected so that two parallel tracks are forrned between the rows of supportpieces for receiving the forks of a pallet lifter. By placing the discrete support piecesappropriately, the parallel tracks may be directed between opposing side sides or between opposing long sides of the support plate.

Although a particular embodiment has been disclosed in detail this has been done forpurpose of illustration only, and is not intended to be limiting. In particular it iscontemplated that Various substitutions, alterations and modifications may be made within the scope of the appended claims.

For example, the support elements 22, 23, 25, 26 may be forrned integrally with thebase plate 11, or they may be fixed thereto. It is also possible to releasable attach thesupport elements 22, 23, 25, 26 to the base plate, for example by bolt and nut joints.This enables adjustments of the width and extension of the tracks, for example to ﬁt different models of pallet lifters.

In particular it is possible combine the embodiments of figure 4 and 5 such that one ortwo of the support elements are in the form of continuous elements and the other support element or elements are in the form of several discrete pieces. 12 Moreover, although speciﬁc terms may be employed herein, they are used in a genericand descriptive sense only and not for purposes of limitation. Furtherrnore, as usedherein, the terms “comprise/comprises” or “include/includes” do not exclude thepresence of other elements. Finally, reference signs in the claims are provided merely asa clarifying example and should not be construed as limiting the scope of the claims in any Way.

Claims

13 Claims

1. A crane unit (1) for hoisting façade elements comprising: -a rectangular base plate (11) having a front short side (12), a rear short side (13) andopposing long sides (14, 15) and upper and lower support surfaces (16, 17), wherein theupper support surface (16) comprises; - a T-shaped crane mast (30), comprising a Vertical boom (31) attached to the centre ofan upper horizontal boom (34) and two pulleys (37, 38) arranged in each end of thehorizontal boom for guiding a winch wire (3 9); - a winch unit (40) for winching a winch wire (39) comprising first and second drivediscs (41, 42) and a winch wire storage reeler (45); - a control unit (5 0) for controlling the winch unit (40); wherein the T-shaped crane mast (30) is arranged adjacent the front short side (12) of the baseplate (11) with the horizontal boom (34) aligned parallel with the long sides (14, 15) ofthe base plate (11) and wherein the winch unit (40) is arranged adjacent the rear shortside (13) of the base plate (11) and wherein, the lower support surface (17) of the base plate (11) comprises two parallel tracks (20,21) of predeterrnined height, length and width for receiVing forks of a pallet lifter.

2. The crane unit (1) according to claim 1, wherein the Vertical boom (31) of the T-shaped crane mast (30) comprises a first and a second beam (32, 33), wherein one endof each beam is attached to the first and second long side (14, 15) respectively andwherein the second end the beams (32, 33) are joined over the centre of the base plate (11) so that the beams (32, 33) form a triangular structure.

3. The crane unit (1) according to claims 1 or 2, wherein the control unit (50) is arranged between the T-shaped crane mast (3 0) and the winch unit (40).

4. The crane unit (1) according to claim 3, wherein the horizontal boom (34) has a first arm (35) and a second arm (36), whereby the second arm (36) is directed towards the 14 rear short side (13) of the base plate (11) and the control unit (50) is arranged undemeath the second arrn (3 6) of the horizontal boom

5. The crane unit (1) according to anyone of claims 1 - 4, wherein the parallel tracks(20, 21) for receiVing the forks of a pallet lifter extends from the rear short side (13) indirection towards the front short side (12) of the of the base plate (11).

6. The crane unit (1) according to claim 5, wherein the parallel tracks (20, 21) forreceiVing the forks of a pallet lifter extends oVer the entire lower support surface (17), from the rear short side (13) to the front short side (12) of the base plate (11).

7. The crane unit (1) according to anyone of claims 1 -6, wherein the lower supportsurface (17) of the base plate (11) comprises at least three support elements (22, 23, 24,25), wherein a first support element (22) is arranged along the first long side (14) of thebase plate (11) and a second support element (23) is arranged along the second long side(15) of the base plate (11) and at least a third support element is (22) arranged betweenthe first and second support elements, wherein the at least first, second and third supportelements (22, 23, 24) are arranged such that two parallel, straight tracks (20, 21) ofpredeterrnined width, length and height, for receiving forks of a pallet truck are formed on the lower support surface (17).

8. The crane unit (1) according to claim 7, wherein at least one of the at least firstsupport element (22), the second support element (23) and the third support element (24) is a continuous piece.

9. The crane unit (1) according to claim 7, wherein at least one of the of the at least firstsupport element (22), the second support element (23) and the third support element (24) comprises several discrete pieces.

10. The crane unit (1) according to any one of claims 1 - 9, wherein the tracks (20, 21) for receiVing forks of a pallet truck are of rectangular cross-section.

11. The crane unit (1) according to anyone of c1ain1s 1 - 10, Wherein the Width of thetracks (20, 21) is in the range of 160 - 240 n1n1, Wherein the height of the tracks (20, 21)is in the range of 50 - 110 mm and Wherein the tracks (20, 21) are spaced apart by a distance in the range of 140 - 200 n1n1.