EP3253706B1 - Crane, in particular bridge crane or gantry crane, having at least one crane girder - Google Patents

Description

The invention relates to a crane, in particular bridge crane or gantry crane, with at least one horizontally extending and designed as truss with multiple struts crane carrier on which a trolley with a hoist is movable, wherein at least some of the struts are formed flat and the sheet-like struts one each Have planar main surface, each extending transversely to a longitudinal direction of the crane girder, wherein on each longitudinal side of the struts a first recess and a second recess in the main surfaces is provided.

Such a crane is from the German patent application DE 10 2012 102 808 A1 known. Here, the struts are arranged in pairs saddle-roof-like and between the struts of each strut pair a vertically extending post is provided. About the struts and posts a top flange and a lower flange of the crane girder are connected. In addition, the struts have stiffening folded longitudinal sides. Due to the folds of the longitudinal sides of auxiliary surfaces are formed between lower first and upper second recesses, which adjoin the main surfaces as so-called Beulsteifen, compared to the major surfaces are bent at approximately right angles and transverse to the longitudinal direction of the crane girder.

In this context, struts are generally considered to be those supporting elements of a truss structure which have an oblique or diagonal course. As a result, the struts of a truss structure differ from the supporting elements, which run exclusively vertically and are referred to as posts. In addition, the sheet-like struts or surface struts preferably absorb forces in the direction of their longitudinal axis and thus in the plane of extent of their flat main surface. Such surface elements or surface structures are referred to in the technical mechanics as discs, whereas perpendicular to their plane of extent or main surface loaded surface elements are referred to as plates. Slices and thus also the present surface struts differ, for example, from rods or rod-shaped posts and struts in that their thickness dimensions are much smaller than the areal extent of the disc determining length and width dimensions. Accordingly, sheet-like struts are also referred to as surface struts or disc struts.

The DE 32 22 307 A1 discloses a truss designed as truss bridge carrier with sheet-like struts.

Other trusses are from the US 327360 A and from the DE 1 907 455 A known.

The invention has for its object to provide a corresponding crane, in particular overhead crane or gantry crane, with at least one improved crane girder ready.

This object is achieved by a crane, in particular bridge crane or gantry crane, with the features of claim 1. In the dependent claims 2 to 12 advantageous embodiments of the invention are given.

In a crane, in particular bridge crane or gantry crane, with at least one horizontally extending and trussed with multiple struts crane carrier on which a crane trolley with a hoist is movable, wherein at least some of the struts are formed flat and the sheet-like struts each have a planar main surface each extending transversely to a longitudinal direction of the crane girder, wherein on each longitudinal side of the struts a first recess and a second recess is provided in the main surfaces, the at least one crane girder is advantageously improved in that the longitudinal sides of at least some of sheet-like struts are at least between the first and second recesses formed without kinking. As a result, the production costs can be further reduced. By the preferably round recesses, the main surface is constricted transversely to the longitudinal axis, whereby the struts in each of these areas form a kind of membrane joint and cause an optimized power flow through the strut. While in conventional sheet-like struts for the production of secondary surfaces between the first and second recesses or membrane joints a complex folding or bending of the longitudinal sides is required, this can be dispensed with in the abkantungsfreien sheet-like struts. As a result, the dimensions, in particular the length and the width of the main surface extending transversely to the longitudinal direction of the crane girder, can be freely selected solely by appropriate choice of the sheet thickness. In addition, the crane girder produced with the struts according to the invention due to the omission of statically unnecessary sheet metal areas and an associated saving of material a significantly reduced weight and at the same time an optimized load capacity.

In a further embodiment, it is provided that the longitudinal sides are formed without kinking over their entire length. As a result, the production cost can be further reduced.

In a structurally simple manner, it is provided that the abkantungsfreien long sides extend only in a plane of the respective main surface.

The aforementioned advantages can be further increased by the fact that the long sides of all struts are formed without kinking. By this, all struts are formed surface-shaped can be compared to conventional truss constructions all individually adapted rod-shaped struts or sheet-like struts with complex to be produced adjacent surfaces replaced by uniformly designed inventive sheet-like struts. This leads to a significant manufacturing advantage, since each sheet-like strut is made of a laser-cut sheet steel without further elaborate manufacturing steps. The structure of the struts is so freely designable only by appropriate laser cutting.

In a particularly advantageous manner, it is further provided that at least a first strut and a second strut form a strut pair and are arranged X-shaped relative to one another transversely to the longitudinal direction of the crane girder. In contrast to the known crane girders in trussed girder construction, the crane girders thus improved are characterized in particular by the fact that no posts have to be used to ensure the required stability of the crane girder. As a result, consequently, the variety of parts can be reduced and material can be saved. At the same time, the torsional stiffness compared to the known Increase truss crane carriers. The risk of buckling of the sheet-like struts and individual crane girder areas can be reduced by the X-shaped arrangement of the intersecting struts.

In a structurally simple manner, it is provided that the two struts of each strut pair each have a recess in one of the longitudinal sides and the two struts are put together via the two recesses.

A simple manufacture of the crane is achieved in that the two struts of each pair of struts are welded together in the region of the recesses.

Advantageously, it is also provided that the recesses in the struts of each strut pair are formed such that the mutually associated longitudinal sides of the X-shaped struts are arranged flush. As a result, a particularly uniform and thus secure mutual support of the two struts of each strut pair is achieved.

In a structurally simple embodiment, it is provided that the recesses extend starting from the respective longitudinal side in the direction of a longitudinal axis of the strut, preferably rectangular, in particular up to the longitudinal axis, and are preferably arranged in the region of half the strut length.

In a structurally simple manner it is provided that at least a first strut and a second strut form a strut pair and are seen transversely to the longitudinal direction of the crane girder V-shaped to each other.

A structurally and manufacturing technology particularly advantageous trained bridge or gantry crane is achieved in that the crane girder comprises at least one straight in the longitudinal direction extending upper chord and at least one parallel thereto arranged lower chord, the upper chord and the lower chord arranged over several along the longitudinal direction of the crane girder Aspirations are interconnected.

In a further advantageous embodiment, it is provided that the crane comprises two crane carriers arranged parallel and at a distance from one another.

• Figur 1 einen als Ein-Träger-Kran ausgebildeten Brückenkran,
• Figur 2 einen Ausschnitt eines erfindungsgemäßen Kranträgers für einen Brückenkran gemäß Figur 1 in einer perspektivischen Ansicht,
• Figur 3 eine Querschnittsansicht des Kranträgers gemäß Figur 2 und
• Figur 4 eine Ansicht einer Strebe des Kranträgers gemäß Figur 2

An embodiment of the invention will be explained in more detail with reference to the drawings. Show it:

• FIG. 1 a bridge crane designed as a single-girder crane,
• FIG. 2 a section of a crane girder according to the invention for a bridge crane according to FIG. 1 in a perspective view,
• FIG. 3 a cross-sectional view of the crane girder according to FIG. 2 and
• FIG. 4 a view of a strut of the crane girder according to FIG. 2

The explanations given below on the basis of a bridge crane also apply accordingly to other types of cranes such as gantry cranes.

The FIG. 1 shows a crane designed as a single-girder crane 1. The crane 1 comprises a truss formed crane carrier 2, which is horizontally aligned and extends with a length L in its longitudinal direction LR.

The crane girder 2 of the crane 1 forms, with its first and second running gears 7, 8 fastened to its opposite ends, a crane bridge which, in plan view, is essentially double-T-shaped. About the trolleys 7, 8 of the crane 1 in a horizontal direction of travel F transverse to the longitudinal direction LR of the crane girder 2 on rails not shown movable. The rails are usually arranged vertically with respect to a floor and can be raised for this purpose, for example via a suitable support structure or attached to opposite building walls. In order to move the crane 1 or its crane carrier 2, the first chassis 7 is driven by a first electric motor 7a and the second chassis 8 by a second electric motor 8a. On the crane girder 2, a crane trolley 9 is suspended by a hoist designed as a cable hoist, which can be moved transversely to the direction of travel F of the crane 1 and along the longitudinal direction LR of the crane girder 2 via landing gear units (not shown). The crane trolley 9 is movable along and on laterally projecting running surfaces 4c of a lower belt 4 of the crane girder 2. The crane 1 also comprises a crane control 10 and a suspension control switch 11 connected therewith, via which the crane 1 or the electric motors 7a, 8a and the crane trolley 9 are separately controlled with the cable pull can be operated. In this case, a load-receiving means of arranged on the trolley 9 cable can be lowered or raised.

The FIG. 2 shows a perspective view of a section of a crane girder 2 according to the invention for the crane 1 according to the FIG. 1 , The truss structure of the crane girder 2 essentially comprises a top chord 3, a bottom chord 4 and a plurality of struts 5 extending diagonally therebetween, via which the top chord 3 is firmly connected to the bottom chord 4. The struts 5 are formed surface-shaped and free from bending and seen in pairs X-shaped viewed transversely to the longitudinal direction LR of the crane girder 2. The X-shaped arrangement of the struts 5 and the structure of the struts 5 will be explained in detail below.

In addition, the truss structure of the crane girder 2 at the opposite ends of the upper flange 3 and the lower flange 4 via one end piece 6 is completed (see FIG. 1 ). About these end pieces 6 of the upper flange 3 and the lower flange 4 are connected to a frame. In addition, the trolleys 7, 8 are attached to the end pieces 6.

The upper belt 3 and the lower belt 4 each extend in a straight line, parallel and spaced apart in the longitudinal direction LR of the crane girder 2 between the chassis 7, 8. Here, the upper belt 3 and the lower belt 4 are vertically spaced from each other. The upper belt 3 is composed of two arranged in a horizontal plane and horizontally spaced from each other first and second Obergurtprofilen 3d, 3e together. The two upper flange profiles 3d, 3e are each formed by an L or angle profile carrier with a leg 3a oriented vertically downwards and a horizontal flange 3f arranged at right angles thereto. The flanges 3f of the upper flange profiles 3d, 3e are in this case preferably in a horizontal plane with an upper end side of the struts 5. In the same way, the lower flange of two Untergurtprofilen 4d, 4e is formed. The downwardly directed legs 3a of the upper belt 3 and the upwardly directed legs 4a of the lower belt 4 face each other. Due to the distance of the outermost edges of the upper belt 3 or of the lower belt 4 seen in the longitudinal direction LR, a width B of the crane girder 2 (see FIG FIG. 3 ). Alternatively, the lower flange 4 may also consist of a one-piece flat profile 4b with two upright legs 4a and a leg 4a connecting horizontal Flange 4f are formed, so that in about a U-shaped cross-section is given. Here, the flange 4f of the flat profile 4b is laterally extended beyond the legs 4a (see also FIG. 3 ). The opposite ends of the flange 4f of the flat profile 4b each form a running surface 4c for trolleys of the trolley 9. Also, the upper flange 3 can basically be formed by a corresponding flat profile 3b.

Starting from one of the two end pieces 6, a plurality of X-shaped arranged pairs of struts are provided in the longitudinal direction LR of the crane girder 2, each comprising a first strut 5h and a second strut 5i. The pairwise X-shaped arrangement of struts 5 is seen in the longitudinal direction LR repeated until the opposite end in the form of the other end piece 6 of the crane girder 2 is reached.

This in FIG. 2 exemplified with reference numerals strut pair is disposed between the two ends of the crane girder 2. The first strut 5h of this strut pair is welded to the upper flange 3 at a first upper node OK1 and the second strut 5i is welded to the lower flange 4 at a first lower node UK1. The first strut 5h accordingly runs diagonally downwards to a second lower node UK2 on the lower chord 4 and the second strut 5i runs diagonally upwards to a second upper node OK2 on the upper chord 3.

In order to be arranged in an X-shape relative to one another and crossing each other, the two struts 5h and 5i of each strut pair each have a slot-shaped recess 5g (see FIG FIG. 4 ) on. About the recesses 5g, the two struts 5h and 5i are put together to form a crossing area KB together. In order to ensure secure mutual support of the two struts 5h and 5i of the strut pairs, the struts 5h and 5i can not only be plugged together but additionally welded together by welding seams S extending along the two recesses 5g in the intersection region KB.

Each strut 5 is inclined with an angle of attack α with respect to an imaginary vertical auxiliary plane which runs at right angles to the upper belt 3 and lower belt 4 extending parallel in the longitudinal direction LR. The angle of attack α is here enclosed by the flat major surface 5a of the respective strut 5 and the auxiliary plane. For the sake of simplicity, the angle of attack α between the main surface 5a and an auxiliary line HL is shown, which lies in the auxiliary plane. Preferably, the angle of attack α is in a range of 35 ° to 55 ° and is particularly preferably 45 °. Depending on the length L of the crane girder 2, the angle of attack α is preferably determined prior to assembly, so that an even number of struts 5 with the same length and at the same angle of attack α are used and all struts 5 can be arranged correspondingly X-shaped.

The X-shaped arrangement of the struts 5 results in a correspondingly large number of upper nodes OK and lower nodes UK (see FIG. 1 ), whereby the upper belt 3 or lower belt 4 serving as rail for the trolley 9 is reinforced against deflection and buckling and the crane beam 2 is stiffened and stabilized overall. As a result, it is also possible to dispense with inserting vertical posts for support between the upper flange 3 and the lower flange 4 in addition to the struts 5.

The struts 5 are aligned within the truss structure of the crane girder 2 so that each of their main surface 5a extends transversely to the longitudinal direction LR of the crane girder 2. In addition, the struts 5 are arranged with their lower first strut ends 5e between the two vertically upwardly pointing legs 4a of the lower chord 4. At their upper second strut ends 5f, the struts 5 are arranged between the two vertically downwardly pointing legs 3a of the upper belt 3. In this case, the upper flange 3 bears with the inner sides of its legs 3a and the lower flange 4 with the inner sides of its legs 4a on longitudinal sides 5b of the struts 5 extending parallel thereto. The struts 5 are welded only in the region of their corresponding adjacent longitudinal sides 5b with the legs 3a, 4a along there formed welds S (see FIG. 3 ). Seen transverse to the longitudinal direction LR of the crane girder 2 is between the legs 3a, 4a of the upper flange 3 and lower flange 4 so only one strut 5 is always provided.

The FIG. 3 shows a cross-sectional view of the crane girder 2 according to the FIG. 2 whose section extends vertically and transversely to the longitudinal direction LR between two adjacent strut pairs. Accordingly, in the FIG. 3 a view of the Junction KB of the basis of FIG. 2 shown strut pair shown. Here, the upper half of the first strut 5h and the lower half of the first strut 5h constructed identically constructed second strut 5i of the strut pair, whereby the basic structure of all sheet-like struts 5 is clear.

The struts 5 are formed as a sheet metal profile with an elongated shape and a main surface 5a having a substantially rectangular cross-section. The struts 5 are preferably made by laser cutting from a steel sheet which forms the main surface 5a. The main surface 5a is bounded substantially by longitudinal sides 5b extending parallel to the longitudinal axis LA and extends along the longitudinal axis LA of the strut 5. At least in a central region, the main surface 5a of the strut 5 extends with a strut width SB over at least half the width B of the crane girder 2 transversely to the longitudinal direction LR of the crane girder 2. The width B corresponds to the distance of the outermost points of the lower belt 4 seen in the longitudinal direction LR or - as in the FIG. 3 shown crane girders 2 - of the upper belt 3, in particular of the longitudinal axis LA outwardly directed away flanges 3f, 4f.

In the area of the opposing lower first and upper second strut ends 5e and 5f, a lower first recess 5c and an upper second recess 5d are respectively provided on both longitudinal sides 5b of the struts 5. Through the recesses 5c, 5d, a constriction of the main surface 5a transversely to the longitudinal axis LA arises in the region of each end of the strut 5e, 5f, whereby the struts 5 each form a kind of membrane joint in these regions. The first and second recesses 5c, 5d are round, preferably circular-arc-shaped, and, with regard to the attachment of the struts 5 to the upper flange 3 and the lower flange 4 of the crane girder 2, cause the force flow to be welded through the strut ends 5e and 5f Struts 5 optimized and the local welds S or the associated weld outlets are relieved. For this purpose, the recesses 5c, 5d are preferably outside the legs 3a, 4a, but adjoin them.

In the in FIG. 3 shown view, the slot-like recesses 5g of the two struts 5h and 5i hidden and therefore not shown. The configuration of the recesses 5g is described below with reference to FIG. 4 described. The FIG. 3 but it is already can be seen that the recesses 5g are formed in the struts 5h and 5i each strut pair in particular such that the this assembled and arranged X-shaped struts 5h and 5i can be arranged flush with their associated longitudinal sides 5b. For this purpose, the recesses 5g of the two struts 5h and 5i each extend starting from the corresponding longitudinal side 5b at right angles to the longitudinal side 5b with a recess length AL approximately up to the longitudinal axis LA. In order to be able to put together the two struts 5h and 5i of the illustrated strut pair for the X-shaped arrangement and the formation of the intersection area KB, the struts 5h and 5i must be positioned so that the recesses 5g are each on opposite longitudinal sides 5b of the struts 5h and 5i are arranged. For welding the struts 5h and 5i assembled in this way, a weld seam S extending over the entire strut width SB then runs along the two recess lengths AL. Preferably, the struts 5h and 5i seen in the longitudinal direction LR are welded on both sides of the crossing area KB.

In addition, each recess 5g is centered on the entire strut length, that is to say in the region of half the strut length, arranged on one of the two longitudinal sides 5b. Alternatively, it is also conceivable that the recesses 5g are arranged eccentrically relative to the entire strut length and, accordingly, also the crossing area KB is not arranged halfway up the height of the X-shaped strut pair.

In addition, at the lower first strut end 5e and / or the upper second strut end 5f in the main surface 5a rectangular-shaped slots (not shown) may be provided to the struts 5 hereby before welding to the upper flange 3 and lower flange 4 on the legs 3a and 4a aufzustecken. It is also conceivable that the two legs 3a and the two legs 4a are not equidistant from each other and then accordingly the longitudinal sides 5b in the region of the strut ends 5e, 5f are spaced far from each other to abut the legs 3a and 4a, respectively and to be welded to it.

In the FIG. 4 is a view of a strut 5 of the crane girder 2 according to FIG. 2 ,

In particular, the central position of the recess 5g in the main surface 5a in relation to the entire strut length is shown. The recess 5g extends from one of the two longitudinal sides 5b substantially rectangular and with a recess width AB to the longitudinal axis LA. The recess width AB corresponds at least to the sheet thickness of the main surface 5a of the struts 5, in order to be able to receive them when plugged together to form a strut pair. It can also be seen that the membrane joints formed by the recesses 5c, 5d are thus arranged in the direction of the longitudinal axis LA between the recess 5g and the respective strut end 5e or 5f, which is welded in the installed state between the legs 3a and 4a, respectively (see FIG. 3 ).

In the in the FIGS. 1 to 4 illustrated embodiment, the longitudinal sides 5b are formed over its entire length and thus over the entire strut length without kinking. Accordingly, the longitudinal sides 5b and the main surface 5a lie in a plane defined by the main surface 5a common plane and folds of the longitudinal sides 5b for forming so-called Beulsteifen are not provided.

Alternatively to the in the FIGS. 1 to 3 illustrated X-shaped arrangement is also a different arrangement of the sheet-like and abkantungsfreien struts 5 conceivable, for example, a pair of V-shaped arrangement (not shown). Here, the struts 5 are free between the upper flange 3 and the lower flange 4 and do not support each other as in the X-shaped arrangement. In addition, the struts 5 then differ from the embodiment used for the X-shaped strut pairs in that they are mirror-symmetrical with respect to their longitudinal axis LA and in this case have no recesses 5g. In particular, the membrane hinges described above are always provided with canting-free struts 5. For large overall strut lengths of the abkantungsfreien struts 5, however, it is also conceivable, for example, in the V-shaped arrangement abkantungsfreier struts 5 that for support between the upper flange 3 and the lower flange 4 in addition to the struts 5 in addition a plurality of vertically extending posts are provided along the longitudinal direction LR of the crane girder 2 between individual struts 5 or pairs of struts are arranged and the upper flange 3 and the lower flange 4 also firmly connect with each other. The posts are preferably formed in a planar shape analogous to the struts 5 and welded to the upper flange 3 and the lower flange 4. For small total strut lengths of the struts 5, but support via posts is not required.

Of course, the crane 1 can not only be designed as a single-girder crane, but also as a two-girder crane, which accordingly comprises two crane girders 2 according to the invention, at the ends of which gantries 7, 8 are fastened again in the usual way, so that seen in plan view, a frame is formed. However, the trolley 9 is not necessarily suspended from the lower chords 4 of the crane girder 2, but can also run on upper chords 3 of the two crane girder 2. Accordingly, the crane trolley 9 arranged centrally between crane girders 2 can be moved along the longitudinal direction LR of the crane girders 2 and between the two crane girders 2. Here, the load-receiving means of arranged on the trolley 9 cable between two crane girders 2 is lowered or raised.

LIST OF REFERENCE NUMBERS

1

crane

2

crane carrier

3

upper chord

3a

leg

3b

low profile

3d

first upper belt profile

3e

second upper chord profile

3f

flange

4

lower chord

4a

leg

4b

low profile

4c

tread

4d

first lower chord profile

4e

second lower chord profile

4f

flange

5

strut

5a

main area

5b

long side

5c

first recess

5d

second recess

5e

first end of the strut

5f

second end of the strut

5g

recess

5h

first strut

5i

second strut

5k

third recess

5l

fourth recess

6

tail

7

first landing gear

7a

first electric motor

8th

second chassis

8a

second electric motor

9

crab

10

crane control

11

Suspension control switch

α

angle of attack

AL

recess length

B

width

F

direction of travel

KB

crossing area

L

length

LA

longitudinal axis

LR

longitudinal direction

OK

upper node point

OK1

first upper node

OK2

second upper node

S

Weld

SB

Strive wide

UK

lower node

UK1

first lower node

UK2

second lower node

Claims (12)

1. Crane (1), in particular a bridge crane or gantry crane, having at least one horizontally extending crane girder (2) designed as a lattice girder having a plurality of struts (5, 5h, 5i), on which crane girder a crane trolley (9) with a hoist can travel, wherein at least some of the struts (5, 5h, 5i) have a sheetlike flat design and the flat struts (5, 5h, 5i) each comprise a planar main surface (5a) which extends in each case transversely to a longitudinal direction (LR) of the crane girder (2), wherein on each long side (5b) of the struts (5, 5h, 5i) a first recess (5c) and a second recess (5d) is provided in the main surfaces (5a), characterised in that the long sides (5b) are formed without bent edges by at least some of the flat struts (5, 5h, 5i) at least between the first and second recesses (5c, 5d).
2. Crane (1) as claimed in claim 1, characterised in that the long sides (5b) are formed without bent edges over their entire length.
3. Crane (1) as claimed in claim 1 or 2, characterised in that the bent edge-free long sides (5b) extend exclusively in a plane of the respective main surface (5a).
4. Crane (1) as claimed in any one of claims 1 to 3, characterised in that the long sides (5b) of all struts (5, 5h, 5i) are formed without bent edges.
5. Crane (1) as claimed in any one of claims 1 to 4, characterised in that at least one first strut (5h) and one second strut (5i) form a strut pair and are disposed in an X shape with respect to one another as seen transversely to the longitudinal direction (LR) of the crane girder (2).
6. Crane (1) as claimed in claim 5, characterised in that the two struts (5, 5h, 5i) of each strut pair each comprise a cut-out (5g) in one of the long sides (5b) and the two struts (5, 5h, 5i) are fitted together by means of the two cut-outs (5g).
7. Crane (1) as claimed in claim 6, characterised in that the two struts (5, 5h, 5i) of each strut pair are welded together in the region of the cut-outs (5g).
8. Crane (1) as claimed in any one of claims 6 or 7, characterised in that the cut-outs (5g) in the struts (5, 5h, 5i) of each strut pair are formed in such a way that the mutually allocated long sides (5b) of the struts (5, 5h, 5i) arranged in an X shape are disposed in a flush arrangement.
9. Crane (1) as claimed in any one of claims 6 to 8, characterised in that the cut-outs (5g) extend starting from the respective long side (5b) in the direction of a longitudinal axis (LA) of the struts (5, 5h, 5i), extend preferably in a rectangular shape, in particular as far as the longitudinal axis (LA), and are disposed preferably in the region of half the strut length.
10. Crane (1) as claimed in any one of claims 1 to 4, characterised in that at least one first strut (5h) and one second strut (5i) form a strut pair and are disposed in a V shape with respect to one another as seen transversely to the longitudinal direction (LR) of the crane girder (2).
11. Crane (1) as claimed in any one of claims 1 to 10, characterised in that the crane girder (2) comprises at least one upper boom (3) extending straight in the longitudinal direction (LR) thereof and at least one lower boom (4) disposed in parallel with the upper boom, wherein the upper boom (3) and the lower boom (4) are connected to one another via a plurality of struts (5, 5h, 5i) disposed in the longitudinal direction (LR) of the crane girder (2).
12. Crane (1) as claimed in any one of claims 1 to 11, characterised in that the crane (1) comprises two crane girders (2) disposed in parallel with and spaced apart from one another.

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