Crane, in particular overhead crane or gantry crane, comprising at least one crane girder

Abstract

The invention relates to a crane, in particular an overhead crane or gantry crane, having at least one crane girder that extends horizontally in a longitudinal direction. The crane is designed as a trussed girder and comprises struts which connect an upper run and a lower run together. The upper run and lower run of the trussed girder are designed in a laminar manner, on which a crane trolley having a lifting gear can be moved. The at least one crane girder is advantageously improved by virtue of the fact that the struts are designed in a laminar manner, each strut has a main surface that extends transversely with respect to the longitudinal direction of the crane girder. The first or second strut end of each strut has at least one aperture on the main surface that lies against the lower run or the upper run.

Claims

1. A crane comprising: at least one trussed crane girder that extends horizontally in a longitudinal direction and comprises struts that connect an upper run and a lower run together, wherein the crane girder is adapted to support a movable crane trolley having a lifting gear, wherein the struts are laminar in shape, each strut comprising a main surface that extends transversely with respect to the longitudinal direction of the at least one crane girder and that at least one aperture is provided on the main surface at a first or second strut end of the struts wherein the lower run or the upper run lies against the main surface.

2. The crane of claim 1, wherein the struts are positionable in a positive-locking manner relative to the lower run or the upper run using the aperture.

3. The crane of claim 2, wherein the struts are connected to the lower run or the upper run using the aperture.

4. The crane of claim 2, wherein the struts are welded to the lower run or the upper run in the region of the aperture.

5. The crane of claim 2, wherein the lower first strut end is provided with a lower aperture, against which the lower run lies, and the upper second strut end is provided with an upper aperture against which the upper run lies.

6. The crane of claim 1, wherein the struts are connected to the lower run or the upper run using the aperture.

7. The crane of claim 6, wherein the struts are welded to the lower run or the upper run in the region of the aperture.

8. The crane of claim 6, wherein the lower first strut end is provided with a lower aperture, against which the lower run lies, and the upper second strut end is provided with an upper aperture against which the upper run lies.

9. The crane of claim 1, wherein the struts are welded to the lower run or the upper run in the region of the aperture.

10. The crane of claim 9, wherein the lower first strut end is provided with a lower aperture, against which the lower run lies, and the upper second strut end is provided with an upper aperture against which the upper run lies.

11. The crane of claim 1, wherein the lower first strut end is provided with a lower aperture against which the lower run lies, and the upper second strut end is provided with an upper aperture against which the upper run lies.

12. The crane of claim 1, wherein the upper run and the lower run each comprise at least one vertical web and the web of the upper run lies against an upper aperture and the web of the lower run lies against a lower aperture.

13. The crane of claim 12, wherein precisely one aperture is provided for each web.

14. The crane of claim 12, wherein either (i) the upper run comprises two of said webs and a common upper aperture is provided in each strut so that the webs of the upper run can be inserted into the common upper aperture, or (ii) the lower run comprises two of said webs and a common lower aperture is provided in each strut so that the webs of the lower run can be inserted into the common lower aperture.

15. The crane of claim 12, wherein the web of the lower run or the web of the upper run is welded to at least one longitudinal side of the corresponding aperture, which longitudinal side extends in parallel with a longitudinal axis of the struts.

16. The crane of claim 1, wherein either (i) the upper run comprises two upper run profiles each having a web, or (ii) the lower run comprises two lower run profiles each having a web.

17. The crane of claim 1, wherein the struts comprise at least one auxiliary surface that is folded at a right angle from the main surface.

18. The crane of claim 1, wherein at least one of the apertures is formed in the shape of a slot and is arranged between the longitudinal sides of the respective main surface.

19. The crane of claim 1, wherein at least two of the apertures are formed in the shape of a shoulder and are arranged opposite one another on the longitudinal sides of the respective main surface.

20. The crane of claim 1, wherein the upper run and the lower run are connected to one another by a plurality of posts arranged along the longitudinal direction of the crane girder, wherein the posts are laminar in shape and comprise at least one aperture.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1a is a top perspective view of an overhead crane that is designed as a present invention;

(2) FIG. 1b is a top perspective view of an overhead crane that is designed as a double-girder crane and has two crane girders in accordance with the present invention;

(3) FIG. 2 is a cross-sectional view of one of the crane girders for an overhead crane designed as a single or double-girder crane;

(4) FIG. 3a is a cross-sectional view of an alternative crane girder for an overhead crane designed as a single or double-girder crane;

(5) FIG. 3b is a cross-sectional view of another alternative crane girder for an overhead crane designed as a single or double-girder crane; and

(6) FIG. 4 is a perspective view of one end of one of the crane girders shown in FIG. 1b.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(7) Referring now to the drawings and the illustrative embodiments depicted therein, a first crane 1a is designed as a single-girder overhead crane. It will be appreciated that the explanations given hereinafter with reference to overhead cranes also apply accordingly to gantry cranes. The first crane 1a includes a crane girder 2 that is designed as a trussed girder and is oriented horizontally and extends with a length L in its longitudinal direction LR. First and second travelling mechanisms 7, 8 are fastened to the opposite ends of the crane girder 2, so that a crane bridge is formed that is substantially I-shaped as seen in plan view (FIGS. 1-2). The first crane 1a can be moved, using travelling mechanisms 7,8, in a horizontal direction of travel F transversely with respect to the longitudinal direction LR of the crane girder 2 on rails, not illustrated. The rails are typically arranged in a position above the ground and for this purpose can be elevated e.g. by means of a suitable support structure or can be fastened to opposite building walls. In order to move the first crane 1a or its crane girder 2, the first travelling mechanism 7 is driven by a first electric motor 7a and the second travelling mechanism 8 is driven by a second electric motor 8a. Suspended from the crane girder 2 is a crane trolley 9 that has a lifting gear designed as a cable winch and can be moved by the travelling mechanisms, not illustrated, transversely with respect to the direction of travel F of the first crane 1a and along the longitudinal direction LR of the crane girder 2. The crane trolley 9 can be moved along and on laterally protruding running surfaces 4c of a lower run 4 of the crane girder 2. The first crane 1a includes and is controlled by a crane controller 10 and a pendant control switch 11 that is connected thereto. The first crane 1a, the electric motors 7a, 8a, and the crane trolley 9 with the cable winch can be controlled and operated separately from one another by the crane controller 10 and pendant control switch 11.

(8) The trussed structure of the crane girder 2 substantially includes an upper run 3, a lower run 4, diagonally extending struts 5 and vertical posts 6. The upper run 3 and the lower run 4 extend in each case for the most part in a linear manner, spaced apart from one another and, with the exception of the opposite ends of the crane girder 2, in parallel in the longitudinal direction LR of the crane girder 2 between the travelling mechanisms 7, 8. In this case, the upper run 3 and the lower run 4 are vertically spaced apart from one another. The upper run 3 is composed of two first and second upper run profiles 3d, 3e that are arranged in a horizontal plane and are horizontally spaced apart from one another.

(9) The two upper run profiles 3d, 3e are formed by an L- or angle-profile girder, and each upper run profile 3d, 3e includes a vertical web 3a and a horizontal flange 3c that are arranged at a right angle thereto. Like the upper run 3, the lower run 4 is likewise composed of two L- or angle profile girders, namely a first lower run profile 4d and a second lower run profile 4e. Each lower run profile 4d, 4e thus includes a horizontal flange 4f and a vertical web 4a that are arranged at a right angle to one another accordingly. The downwardly directed webs 3a of the upper run profiles 3d, 3e of the upper runs 3 and the upwardly directed webs 4a of the lower run profiles 4d, 4e of the lower runs 4 face towards one another. Moreover, the spaced interval of the outermost edges of the flanges 3c, 4f of the upper run profiles 3d, 3e or of the lower run profiles 4d, 4e of the lower run 4, as seen in the longitudinal direction LR, produces or defines a width B of the crane girder 2.

(10) However, it is likewise possible that the lower run 4 of the crane girder 2 of a first crane 1a may be designed as a single-girder overhead crane that is not formed by two lower run profiles 4d, 4e but rather by a flat profile having two webs standing perpendicularly, similar to webs 4a described above. In the case of such a flat profile, which includes an approximately U-profile-shaped cross-section, the flange 4f is extended laterally beyond the webs 4a. In this case, the opposite ends of the flange 4f form the running surfaces 4c.

(11) Alternatively, the lower run 4 can also be formed by an upside down T-profile girder that includes a web 4a pointing vertically upwards. Corresponding to the inverted T-shape, the web 4a of the T-profile girder is connected by its lower end centrally to a horizontal flange 4f. In this case, the opposite ends of the flange 4f each form a running surface 4c for travelling mechanisms of the crane trolley 9.

(12) The upper run 3 and the lower run 4 are connected to one another by a plurality of struts 5 and posts 6 that are designed in a laminar manner. In this case, the struts 5 are formed as a sheet metal profile having a main surface 5a with a substantially rectangular cross-section, wherein the longitudinal sides thereof are overturned in the form of auxiliary surfaces 5b to increase the buckling strength at least in a central region. The basic structure of the laminar posts 6 corresponds—in the case of correspondingly adapted dimensions—substantially to the structure of the laminar struts 5. In this case, each of the laminar posts 6 extends with a main surface 6a transversely with respect to the longitudinal direction LR of the crane girder 2. In addition, auxiliary surfaces 6b can be provided that are folded at a right angle with respect to the main surface 6a and extend in the longitudinal direction LR (FIG. 1b). The laminar posts 6 can also be arranged or oriented in such a manner that the auxiliary surfaces 6b point towards or away from one of the ends of the crane girder 2.

(13) The structure of the struts 5 and the posts 6 is will be described in detail hereinafter with reference to FIG. 2.

(14) The trussed structure of the crane girder 2 is terminated at each opposite end of the upper run 3 and of the lower run 4 by an adapter 12. Using the adapters 12, the upper run 3 and the lower run 4 are connected to form a frame. On the whole, the frame of the crane girder 2 is extended from the bottom to the top and is formed in a trapezoidal manner. Moreover, in the region of the upper run 3 and on the side facing away from the upper run 3, the adapter 12 includes a connecting plate 12a, to which one of the travelling mechanisms 7, 8 or the girder thereof is fastened via bores 12d.

(15) Starting from one of the two adapters 12 as seen in the longitudinal direction LR of the crane girder 2, a first strut 5 is connected to the lower run 4 and extends in the longitudinal direction LR inclined at a first setting angle α1 in the direction of the upper run 3 and is fastened at that location in an upper node point OK. In this case, the first setting angle α1 is enclosed by the first strut 5 and a post 6 terminating in the upper node point OK. Preferably, the first setting angle α1 is in a range of 35 degrees to 55 degrees and in a particularly preferred manner is 45 degrees. In the upper node point OK, a second strut 5 extends obliquely from the upper node point OK at the setting angle α1 downwards to the lower run 4. This is repeated until the struts 5 reach the opposite end of the crane girder 2. Therefore, each strut 5 together with post 6 forms, in the region of the corresponding upper node point OK on the upper run 3, a first setting angle α1 of the same size. In this case, an even number of struts 5 are arranged in the manner of a pitched roof obliquely or diagonally with respect to one another is always used, so that the last strut 5 terminates at the lower run 4. The setting angle α1 is determined prior to assembly, depending upon the length L of the crane girder 2, so that an even number of struts 5 is used that each have the same length and are at the same setting angle α1. As a consequence, the lower run 4, which serves as a rail and for this purpose forms the running surface 4c, is reinforced to protect it against bending.

(16) The struts 5 are oriented within the trussed structure of the crane girder 2 such that in each case their main surface 5a extends transversely with respect to the longitudinal direction LR of the crane girder 2. Moreover, the struts 5 are arranged and placed with their lower first strut ends 5g between the mutually facing inner sides of the webs 4a of the lower run profiles 4d, 4e and are welded thereto. For this purpose, lower aperture 5e, which is not illustrated in FIG. 1a, is arranged in each case on the lower first strut ends 5g in the corner region of both longitudinal sides of the struts 5. The formation of the lower apertures 5a corresponds to that illustrated in detail in FIG. 3b in conjunction with the crane girder 2 for an overhead crane designed as a double-girder crane. In the region of the lower apertures 5e, the longitudinal sides are set back approximately by the thickness dimension of a web 4a in the direction of the longitudinal axis LA of the strut 5. The webs 4a of the lower run profiles 4d, 4e are placed in the shoulder thus produced. In this case, the horizontal flanges 4f of the lower run profiles 4d, 4e each point outwards and thus away from the struts 5.

(17) In the case of lower run 4 that is designed as a T-girder, the struts 5 are attached with their lower first strut ends 5g onto the upwardly pointing web 4a of the lower run 4. In this case, the web 4a is received by a lower aperture 5e that is provided in the region of the lower first strut end 5g and is formed to be substantially complementary to the web 4a. Accordingly, the lower aperture 5e is arranged along a longitudinal axis LA of the strut 5 and in relation to a width of the main surface 5a of the strut 5 centrally therein. By inserting the web 4a of the lower run 4 into the lower aperture 5e of the strut 5, the lower run 4 and the strut 5 are thus positioned with respect to one another.

(18) In a corresponding manner, in the case of lower run 4 that is designed as flat profile or consists of two lower run profiles 4d, 4e, the two webs 4a can be received by two lower apertures 5e that are arranged in the main surface 5a of each strut 5, and which can be arranged not only in the corner region, but also between the longitudinal sides of the strut 5 and the longitudinal axis LA thereof in the main surface 5a (see FIG. 2).

(19) At their upper second strut ends 5h, the struts 5 are arranged between the two upper run profiles 3d, 3e, wherein the upper run profiles 3d, 3e are welded with the inner sides of their webs 3a to the struts 5. For this purpose, in a similar manner to the lower apertures 5e, corresponding upper apertures 5i, not illustrated in FIG. 1a, are arranged on the longitudinal sides of the upper second strut end 5h, in which the webs 3a are located. In this case, the horizontal flanges 3c of each of the upper run profiles 3d, 3e point outwards and thus away from the struts 5.

(20) The laminar posts 6 are arranged in the same manner as the struts 5 with their lower first post end 6g and their upper second post end 6h between the webs 3a, 4a of the upper run 3 or lower run 4 and are welded thereto. For this purpose, the posts 6 also include, on the longitudinal sides of their main surfaces 6a, corresponding lower apertures 6e and upper apertures 6i.

(21) In the case of lower run 4, which is designed as a T-girder, the posts 6 are slid with their lower first post ends 6g or lower aperture 6e disposed therein onto the web 4a of the lower run 4 and are welded thereto. The same applies in the case of upper run 3, which is designed as a T-girder, for the upper second post end 6h.

(22) As seen transversely with respect to the longitudinal direction LR of the crane girder 2, only one strut 5 and one post 6 are ever provided between the webs 3a of the upper run 3.

(23) FIG. 1b shows second crane 1b that is designed as a double-girder overhead crane and includes two crane jibs 2 in comparison with the first crane 1a designed as a single-girder overhead crane. The two crane girders 2 are adjusted to the desired length L and arranged spaced apart from another in parallel using adapters 12 that are slid on at their opposite ends. The travelling mechanisms 7, 8, which are also illustrated, are fastened to the ends of the two crane girders 2 using the adapters 12, so that a frame is formed as seen in plan view. The second crane 1b also includes a crane trolley 9 having a lifting gear designed as a cable winch. However, the crane trolley 9 is not suspended from the lower runs 4 of the crane girders 2 but rather runs on upper runs 3 of the two crane girders 2. For this purpose, rail 13 having a corresponding running surface 13a is provided, preferably centrally, on each of the two upper runs 3, so that the crane trolley 9 is arranged between the crane girders 2. Accordingly, the crane trolley 9, which is arranged centrally between the crane girders 2, is moved along the longitudinal direction LR of the crane girders 2 and between the two crane girders 2 and between the travelling mechanisms 7, 8. In this case, the cable winch is arranged on the crane trolley 9 to lower and raise a load between the two crane girders 2.

(24) For the remainder, the statements given with respect to the first crane 1a apply accordingly for the second crane 1b.

(25) The trussed structures of the two crane girders 2 of the second crane 1b include, again, lower run 4 and upper run 3. The upper runs 3 and the lower runs 4 are designed in the same manner as in the case of the first crane 1a, shown in FIG. 1a, and accordingly are composed of a first and second upper run profile 3d, 3e and first and second lower run profile 4d, 4e, wherein the upper run profiles 3d, 3e and lower run profiles 4d, 4e are formed by an L- or angle-profile girder.

(26) However, instead of being composed of two lower run profiles 4d, 4e the lower run 4 of the second crane 1b can essentially also consist of a flat profile or of an upside down T-profile girder.

(27) The upper run 3 of each crane girder 2 is connected to the associated lower run 4 by the plurality of laminar struts 5 and the plurality of likewise laminar, vertically oriented posts 6. The struts 5 and the posts 6 are identical in each case for the two crane girders 2 of the second crane 1b, i.e., as in the case of the first crane 1a shown in FIG. 1a, they are designed in a mirror-symmetrical manner in relation to their longitudinal axis LA.

(28) Furthermore, it is evident in FIG. 1b that the struts 5 are arranged in the manner of a pitched roof in the same manner as in the case of the crane girder 2 shown in FIG. 1a. In this case, two adjacent struts 5 are likewise allocated one post 6, which is designed in a laminar manner, such that struts 5 and the post 6 impinge upon one another at a common lower node point UK on the lower runs 4. Therefore, each strut 5, together with the associated laminar post 6 in the region of the corresponding lower node point UK on the lower runs 4, forms an identically large second setting angle α2, which just like the first setting angle α1, is preferably in a range of 35 degrees to 55 degrees and in a particularly preferred manner is 45 degrees. Therefore, by reason of the even number of struts 5 arranged correspondingly in pairs, the last strut 5 descends towards the lower run 4 at both ends of the crane girder 2. However, unlike in the case of the crane girder 2 shown in FIG. 1a, laminar post 6 is also arranged at each end of the crane girder 2 after the last strut 5. Moreover, auxiliary surfaces 6b are provided that are folded differently compared to the posts 6 shown in FIG. 1a. For each crane girder 2, the auxiliary surfaces 6b are folded in the same direction towards the same end of the crane girder 2, but in the case of one of the crane girders 2 they are folded towards the first travelling mechanism 7, and in the case of the other one of the crane girders 2 they are folded towards the second travelling mechanism 8.

(29) FIG. 2 shows a cross-sectional view of one of the two crane girders 2 for an overhead crane that is designed as a double-girder crane. FIG. 2 shows in particular the basic structure of the struts 5 that corresponds substantially to the basic structure of the posts 6, which are likewise designed in a laminar manner, but can differ therefrom in particular in terms of dimensions. The statements in relation to FIG. 2 also apply to the crane girder 2 of an overhead crane designed as a single-girder crane, as shown in FIG. 1a. For the sake of simplicity, with respect to the description of FIG. 2 reference is made only to the struts 5; the reference numerals 5a to 5j mentioned in this case similarly designate the corresponding elements of the laminar posts 6, which are indicated at the same points as reference numerals 6a to 6j and are listed in the list of reference numerals.

(30) The strut 5 illustrated in FIG. 2 and designed in a laminar manner includes an elongated shape having a substantially rectangular main surface 5a. The main surface 5a extends along the longitudinal axis LA of the strut 5, and in each case in a central region over at least half the width B of the crane girder 2 in a transverse manner with respect to the longitudinal direction LR of the crane girder 2. The struts 5 are produced preferably by laser cutting from a steel sheet. Moreover, the struts 5 have lower first strut end 5g and upper second strut end 5h. In the region of their opposite lower first and upper second strut ends 5g, 5h, two lower recesses 5c and two upper recesses 5d are provided on both longitudinal sides of the strut 5. The recesses 5c, 5d are circular, preferably circular arc-shaped, in formation and, with regard to the welding of the struts 5 to the upper run 3 or the lower run 4 of the crane girder 2, ensure that the distribution of forces is optimized by the welded struts 5 and the weld seams S or the weld seam run-outs are relieved.

(31) Between the lower and upper recesses 5c, 5d, auxiliary surface 5b, which is folded at a right angle and extends in parallel with the longitudinal axis LA, adjoins the main surface 5a at each longitudinal side of the strut 5. The auxiliary surfaces 5b are formed substantially in a trapezoidal manner (see also FIG. 4). By virtue of the fact that the auxiliary surfaces 5b are both folded in the same direction, the strut 5 illustrated in FIG. 2 has, at least in the region of the auxiliary surfaces 5b, a U-shaped cross-section as seen in the direction of the longitudinal axis LA of the strut 5. It is likewise feasible for the auxiliary surfaces 5b to be folded in opposite directions, so that, as seen in the direction of the longitudinal axis LA, a Z-shaped cross-section would be produced at least in part. By omitting auxiliary surface 5b or by providing merely one single auxiliary surface 5b, the strut 5 can also include, in a corresponding manner, an at least partially L-shaped cross-section as seen in the direction of the longitudinal axis LA. The auxiliary surfaces 5b serve to increase the buckling strength of the struts 5. The auxiliary surfaces 5b are located outside the webs 3a, 4a, so that only non-overturned regions of the main surfaces 5a are welded to the webs 3a, 4a.

(32) The lower run 4 is formed by two lower run profiles 4d, 4e, wherein a structure of the lower first strut ends 5g and of the upper second strut ends 5h of the struts is produced, which differs from the arrangement shown in FIGS. 1a and 1b, and of which the structure is feasible in each case both for the first crane 1a and for the second crane 1b.

(33) Three strut feet 5f are formed on the lower first strut end 5g of the strut 5, in that two lower apertures 5e for receiving the webs 4a of the lower run 4 are provided on the lower first strut end 5g in the main surface 5a. The lower apertures 5e are formed as substantially rectangular slots that each extend at the same spaced interval on the right and left with respect to the longitudinal axis LA and in parallel therewith in the main surface 5a. Accordingly, the main surface 5a extends between the slot-shaped lower apertures 5e likewise in a rectangular manner to the lower first strut end 5g and forms at this location third central strut foot 5f. The two lower apertures 5e are spaced apart from one another by the central strut foot 5f. In each case, one of the upwardly pointing webs 4a of the lower run profiles 4d, 4e is inserted into one of the lower apertures 5e, so that each of the slot-shaped apertures 5e can lie with its upper end on one of the webs 4a. However, in this case the two outer strut feet 5f do not lie on the flanges 4f of the lower run profiles 4d, 4e.

(34) The two lower apertures 5e in FIG. 2 are formed to be substantially complementary to the webs 4a of the respective lower run profile 4d, 4e of the lower run 4 and have dimensions suitable for receiving the webs 4a. In this case, the two outer strut feet 5f are arranged on outer sides of the two webs 4a and the central strut foot 5f is arranged between the opposite inner sides of the two webs 4a, so that both webs 4a are arranged accordingly between the outer strut feet 5f. In this case, the webs 4a lie with their inner and outer sides against the longitudinal sides of the lower apertures 5e extending in the longitudinal direction LA and are welded to the struts 5 at this location. The positioning or orientation of the lower run profiles 4d, 4e with respect to each strut 5 is achieved by the corresponding arrangement of the lower apertures 5e in the main surface 5a of the strut 5.

(35) The structure of the lower strut feet 5f, as shown in FIG. 2 for the second crane 1b, is also feasible for the first crane 1a, if its lower run 4 is formed by a flat profile having two webs similar to webs 4a.

(36) Also, in the case of lower run 4 designed as a T-girder, lower aperture 5e is provided centrally or, in relation to the longitudinal axis LA, in a centered manner on the lower first strut end 5g in the main surface 5a of the strut 5 and has a cross-section that is mirror-symmetrical in relation to the longitudinal axis LA and which, starting from the lower first strut end 5g, tapers upwards approximately in a trapezoidal manner, and terminates with a rectangular slot adjoining it. The lower aperture 5e is thus formed to be substantially complementary to the web 4a and has dimensions that are correspondingly suitable for receiving the webs 4a, whereby a positive-locking connection can be produced between the lower run 4 and the strut 5 by means of the lower aperture 5e.

(37) The upwardly pointing web 4a of the T-shaped lower run 4 is inserted into the lower aperture 5e, so that the lower aperture 5e lies with its slot-shaped upper end on the web 4a. In this case, the strut feet 5f lie on the flange 4f of the lower run 4 and are welded to the flange 4f in each case by means of horizontally extending weld seams S. Moreover, in this case the strut feet 5f lie, with longitudinal sides of the lower aperture 5e extending in the longitudinal direction LA, against outer sides of the web 4a extending in parallel therewith, and are welded at this location to the web 4a likewise by means of weld seams S.

(38) Two strut arms 5j are formed on the upper second strut end 5h in the region of the upper corners of the struts 5, in that upper aperture 5i having a substantially rectangular cross-section is provided in the main surface 5a centrally on the upper second strut end 5h and in a centered manner in relation to the longitudinal axis LA of the strut 5. The upper aperture 5i extends, starting from the upper second strut end 5h, in parallel with the longitudinal axis LA, wherein the opposite longitudinal sides of the upper aperture 5i extends at the same spaced interval on the right and left of the longitudinal axis LA. As seen transversely with respect to the longitudinal axis LA, the upper aperture 5i is dimensioned in such a manner that at least the two vertically downwards pointing webs 3a of the two upper run profiles 3d, 3e can be inserted or pushed into the upper aperture 5i. However, in order to ensure that at the ends of the crane girders 2 a stiffening rib 12c of the adapter 12 can be pushed between the mutually facing inner sides of the webs 3a (see also FIG. 4), the upper apertures 5i of the struts 5 are preferably dimensioned to be correspondingly wider in dependence upon the thickness of the stiffening rib 12c. It is also preferable that the webs 3a and the stiffening ribs 12c are approximately the same thickness, so that, as seen transversely with respect to the longitudinal axis LA of the strut 5, the upper aperture 5i is approximately three times as wide as the thickness of one web 3a or the stiffening rib 12c.

(39) It is also evident in FIG. 2 that the webs 3a of the two upper run profiles 3d, 3e lie with their outer sides facing the longitudinal sides of the upper aperture 5i against the longitudinal sides and that at that location a welding connection is established along the weld seams S. A further welding connection is provided between the upper run 3 and the upper second strut ends 5h, in particular in the form of horizontal weld seams S between the strut arms 5j and the flanges 3c of the upper run profiles 3d, 3e, which flanges lie on the end sides of the strut arms pointing in the direction of the longitudinal axis LA.

(40) Instead of being formed from the two upper run profiles 3d, 3e, the upper run 3 can also be formed by flat profile formed in a similar manner to the optional flat profile described above with reference to the lower run 4 of the crane girder 2 of the first crane 1a, and therefore can be formed in one piece.

(41) As an alternative to the illustration in FIG. 2, it is also feasible that, similar to the lower apertures 5e, two upper apertures 5i are provided instead of only one upper aperture 5i. The main surface 5a can then extend both between the lower apertures 5e and the upper apertures 5i in the direction of the upper second strut end 5h and form a central third strut arm 5j at this location. In particular, the central strut arm 5j formed by the main surface 5a can drop back at this location with respect to the end sides of the strut feet 5f or the ends sides of the two outer strut arms 5j as seen in the direction of the longitudinal axis LA, if the apertures 5e, 5i include at least one slot-shaped cross-section that is deep enough to receive or position the webs 3a, 4a of the upper and lower runs 3, 4.

(42) As already indicated in FIG. 1a, the upper second strut end 5h can also be provided with two upper apertures 5i, each having a rectangular cross-section in the longitudinal sides of the main surface 5a. The longitudinal sides are set back in a stepped or shoulder-like manner by the upper apertures 5i in the region of the upper corners and in the direction of the longitudinal axis LA. Accordingly, the longitudinal sides of the main surface 5a are spaced less far apart from one another in the region of these shoulder-like upper apertures 5i than in the region of the folds of the auxiliary surfaces 5b. In this case, the upper apertures 5i, starting from the upper second strut end 5h in the direction of the longitudinal axis LA, are preferably dimensioned such that they correspond approximately to the length of the webs 3a of the upper run profiles 3d, 3e. The offset of each longitudinal side transverse to the longitudinal axis LA corresponds approximately to the thickness of one of the webs 3a. The upper run profiles 3d, 3e are easily connected in a positive-locking manner to the struts 5 using the laterally arranged upper apertures 5i, and thereby oriented with respect to one another, in that the webs 3a thereof are placed with their inner sides, facing the strut 5, against the set-back longitudinal sides in the upper apertures 5i. Then, by forming corresponding weld seams S the upper run profiles 3d, 3e are welded to the struts 5. In this case, the flanges 3c of the upper run profiles 3d, 3e lie with the end side—pointing in the direction of the longitudinal axis LA—of the upper second strut end 5h preferably in a horizontal plane.

(43) It is also essentially feasible that in the case of the second crane 1b the struts 5 do not have any strut feet 5f formed thereon. Instead, the lower first strut end 5g can be provided in the longitudinal sides of the main surface 5a with two laterally arranged lower apertures 5e that form shoulders and against which the webs 4a of the lower run 4 lie with their inner sides and are welded.

(44) For the second crane 1b, which is designed as a double-girder overhead crane, the webs 3a of the upper run profiles 3d, 3e are arranged preferably closer to one another and thus less far apart from the longitudinal axes LA of the struts 5 than the webs 4a of the lower run profiles 4d, 4e. As a result, the upper run profiles 3d, 3e of each upper run 3 of the two crane girders 2 can be connected to one another by the rail 13—likewise illustrated in FIG. 2—on upper sides facing away from the webs 3a. Therefore, in order to connect the upper run profiles 3d, 3e, which are arranged horizontally next to one another, a corresponding rail 13 is welded on the upper sides of the upper run profiles 3d, 3e.

(45) The rails 13 have a rectangular cross-section and form on their upper sides one of the running surfaces 13a for the travelling mechanisms, not illustrated here, of the crane trolley 9. Each rail 13 is arranged preferably centrally or in a centered manner with respect to the two parallel webs 3a of the corresponding upper run profiles 3d, 3e and thus also in a centered manner with respect to the longitudinal axis LA of the strut 5. Moreover, the rail 13 is dimensioned in such a manner that it bridges the spaced interval between the webs 3a inserted into the upper aperture 5i and can be welded to the flanges 3c of the upper run profiles 3d, 3e along the longitudinal direction LR of the crane girder 2.

(46) In one possible embodiment, the total length of strut 5 is 890 mm. In this case, the webs 3a, 4a of the upper and lower runs 3, 4 are each inserted with an insertion length of 80 mm into the apertures 5e, 5i or are welded to the longitudinal sides of the apertures 5e, 5i over the length. The spaced interval between the apertures 5e, 5i, which receive the webs 3a, 4a, and the auxiliary surfaces 5b, i.e. the length of the membrane joints formed in this region, is then 100 mm in each case. Accordingly, the auxiliary surfaces 5b have an auxiliary surface length of 530 mm in relation to the longitudinal axis LA, i.e. auxiliary surfaces 5b extend in their longitudinal direction over the auxiliary surface length of 530 mm.

(47) The auxiliary surface lengths are thus preferably in a range of about 40 percent to 70 percent of the total length of the strut 5 and the insertion lengths are in a range of about 5 percent to 15 percent of the total length of the strut 5.

(48) FIGS. 3a and 3b show in each case a further cross-sectional view of one of the two crane girders 2 for an overhead crane that is designed as a double-girder crane. The upper runs 3 and lower runs 4, which are illustrated and are described hereinafter and thus also the struts 5 and posts 6, can be formed in the same manner in an overhead crane that is designed as a single-girder overhead crane.

(49) The upper run 3 of the crane girder 2 is formed in each case in one piece as a T-girder having vertically oriented web 3a and horizontally oriented flange 3c. The web 3a points downwards in the direction of the lower run profiles 4d, 4e of the lower run 4 and is inserted in each case into the slot-shaped upper aperture 5i of the struts 5 that extends in the main surface 5a thereof centrally along the longitudinal axis LA in the direction of the lower run 4 and hereby forms the two strut arms 5j. The upper apertures 5i correspond in terms of their structure to the lower apertures 5e described above in conjunction with lower run 4 designed as a T-girder, and are formed substantially in the shape of a slot having a rectangular cross-section.

(50) In both of FIGS. 3a and 3b, the rail 13 is welded centrally on the flange 3c on the side facing away from the web 3a.

(51) The upper aperture 5i shown in FIG. 3a differs from the one shown in FIG. 3b by virtue of the fact that its end facing towards the lower run 4 widens in drop-shaped manner with a roundish or bulbous progression. In contrast, the corresponding end of the upper aperture 5i shown in FIG. 3b is substantially rectangular and formed without any widening. Furthermore, in FIG. 3a in the region of the upper second strut end 5h the struts 5 do not have any upper recesses 5c provided therein which in contrast, e.g. also in the strut 5 shown in FIG. 3b, are arranged between the strut arms 5j and the folded auxiliary surfaces 5b. In FIG. 3a, the auxiliary surfaces 5b thus directly adjoin the longitudinal sides of the strut arms 5j.

(52) Furthermore, FIG. 3b shows on the lower first strut end 5g of the strut 5 lateral lower apertures 5e, against which the lower run profiles 4d, 4e are placed and welded with their vertically oriented webs 4a. The statements already made above for lateral upper apertures 5i apply accordingly in this case.

(53) FIG. 4 shows a perspective view of one end of one of the two crane girders 2 for the second crane 1b shown in FIGS. 1b and 2 with one of the two adapters 12 that are arranged on both of the opposite ends. The crane girder 2 is designed as a trussed girder having upper run 3 composed of two upper run profiles 3d, 3e, and having lower run 4 composed of two lower run profiles 4d, 4e. The rail 13, which extends in the longitudinal direction LR, is welded on the flanges 3c of the upper run profiles 3d, 3e centrally in relation to the width of the crane girder 2. Also apparent are two struts 5 that are positioned in each case at the second setting angle α2 with respect to laminar post 6 and come together therewith at a lower node point UK on the lower run 4. The lower run 4 or the lower run profiles 4d, 4e thereof extend, in the region of the ends of the crane girder 2 in each case after the first or last strut 5, in a manner guided diagonally upwards in the direction of the upper run 3.

(54) FIG. 4 also shows the trapezoidal formation of the auxiliary surfaces 5b of the struts 5b that are folded from the main surfaces 5a and the corresponding auxiliary surface 6b of the laminar post 6. The auxiliary surfaces 5b, 6b are arranged outside the webs 3a, 4a of the upper and lower runs 3, 4 and extend in a vertical plane, which includes the longitudinal direction LR of the crane girder 2.

(55) In order to adjust the desired length L of the crane girders 2, the adapter 12 is placed against the upper run 3 and the lower run 4, oriented in the longitudinal direction LR and welded.

(56) As already indicated in FIG. 2, FIG. 4 illustrates the stiffening rib 12c that is arranged on the connecting plate 12a or on a head plate 12b connected thereto at a right angle. The stiffening rib 12c is formed in a flat and planar manner and extends, starting from the connecting plate 12a, diagonally upwards with respect to the head plate 12b. When the adapter 12 is slid onto the crane girder 2, the stiffening rib 12c is pushed between the webs 3a of the upper run profiles 3d, 3e and is welded thereto. Accordingly, FIG. 4 indicates that the webs 3a of the upper run 3 are not oriented in each case in a vertically flush manner with the webs 4a of the lower run 4, but rather are spaced less far apart from one another in the horizontal direction than the webs 4a. For this purpose, in each strut 5 the upper aperture 5i shown in FIG. 2 is dimensioned correspondingly, in particular such that the stiffening rib 12c can be pushed between the two webs 3a protruding into the upper aperture 5i.

(57) Moreover, FIG. 4 shows the first lower node point UK which, starting from the illustrated end of the crane girder 2, is located on the lower run 4 and on which the first two struts 5 and the first post 6, which are each designed in a laminar manner, come together. In the region of the lower node point UK, each of the two struts 5 together with the post 6 forms one of the second setting angles α2. The two outer strut feet 5f as well as the post feet 6f lie against the outer sides of the webs 4a of the lower run 4.

(58) However, the post 6 includes on its lower first post end 6g one rectangular lower aperture 6e and thus two outer post feet 6f, against the inner mutually facing longitudinal sides of which the webs 4a lie with their outer sides. Therefore, a dedicated lower aperture 6e is not provided in the post 6 for each web 4a.

(59) In contrast, the lower first ends 5g of the struts 5 have two lower apertures 5e formed thereon, of which each receives one of the webs 4a. However, the upper second strut ends 5h and the second upper post end 6h have a similar structure with merely one upper aperture 5i or 6i, into which the webs 3a of the upper run profiles 3d, 3e are inserted and against the inner sides of which the webs 3a lie. Accordingly, the strut arms 5j or post arms 6j formed by these upper apertures 5i, 6i lie in a similar manner to the two outer strut feet 5f or the post feet 6f against the outer sides of the webs 3a of the upper run 3.

(60) Essentially, it is also possible that the lower first strut ends 5g are formed in a similar manner to the lower first post ends 6g with only one rectangular lower aperture 5e and accordingly with only two outer strut feet 5f, so that the struts 5 are oriented with respect to the lower run 4 by the longitudinal sides of the merely one lower aperture 5e.