DE29512549U1 - Gantry crane with truss - Google Patents

Description

Hünchen, 3 August 1995

Our sign: V 579

Applicant/Owner: VULKAN KOCKS GMBH Official reference number:

> Bremen
Patent Attorneys European Patent Attorneys Dipl.-Ing. Günther Eisenführ Dipl.-Ing. Dieter K. Speiser Dr.-lng. Werner W. Rabus Dipl.-Ing. Jürgen Brügge Dipl.-Ing, Jürgen Klinghardt Dipl.-Ing. Klaus G. Göken

Attorney Ulrich H. Sander

Munich

Patent attorneys

European Patent Attorneys

Dipl.-Phys. Gerhard Liedl

Dipl.-Wirtsch.-Ing, Rainer Fritscr

Patent Attorney

Dipl.-Chem. Dr. Peter Schuler

Berlin

Patent Attorney European Patent Attorney Dipl.-Ing. Jutta Kaden

Herterichstrasse 18 D-81479 Munich Tel. 089-79 9096-98 Fax 089-7901 777

Gantry crane with space frame

The invention relates to a gantry crane for handling goods, in particular for container handling with feeder ships according to the preamble of claim 1.

Such gantry cranes are used, for example, to unload goods that have been transported by ship from these ships and to transfer them either to a storage area or to another means of transport, such as a truck or railway wagon.

To raise and lower the goods to be handled using the trolley and to move the gantry crane itself, such gantry cranes known in practice have several drive units, which may be connected via a

common energy source. In the gantry cranes known in practice, the drive units are mounted at various points on the gantry crane. The mounting point is usually determined by the space available on the base frame. If there is no point on the base frame that has sufficient space for all the installations to be mounted, the drives are arranged at various points on the outside of the gantry crane. This increases the assembly effort considerably, since the individual drives can only be mounted at the location where the gantry crane is installed. In addition, although the individual drives can be tested on their own before they are mounted on the gantry crane, it is not possible to test the joint function of all the drives with one another. Finally, considerable lengths of cable must be laid in order to be able to connect the individual drives to one another so that a combined effect is possible.

It is an object of the present invention to provide a gantry crane of the type mentioned at the outset, which allows a space-saving installation of at least one drive of the gantry crane.

The above object is achieved by the features of claim 1. By designing at least one section of the basic structure as a space framework, the possibility is opened up of installing at least one drive, namely the one for the trolley hoist, within this space framework. In contrast to the known gantry cranes, this drive does not need to be installed on the outside of the gantry crane, so that the gantry crane according to the invention has a more compact structure than known gantry cranes.

The space framework can have any shape. For example, it is conceivable that the space framework has a triangular shape when viewed in cross-section. It is also possible for the space framework to have an essentially rectangular, preferably square, cross-section.

• · &ogr; ··

In principle, the space frame can be provided at any point on the gantry crane. If it forms the bridge section of the gantry crane, to which another boom may be connected, the almost central arrangement of the drive of the trolley hoist improves the overall weight distribution of the gantry crane. The other boom can be pivoted with a pivot axis that can be moved in a vertical plane, or it can be rigidly connected to the bridge section.

In principle, the drive of the trolley hoist can be arranged in the space frame without any weather protection. However, in order to prepare the individual installations more easily and to better protect the drive for the trolley hoist from the effects of the weather, it can also be provided that the drive of the trolley hoist is housed in a house. The house itself can be used to stiffen the space frame.

In addition to the drive for the trolley hoist, other drives and/or electrical switchgear of the gantry crane can also be housed in the space frame, which further improves the weight distribution or the center of gravity of the gantry crane, particularly in the case of a space frame as a bridge section. For example, a combustion-powered energy source, possibly housed in a house, can be provided, which is designed as a diesel-electric system. The diesel-electric system has a diesel engine, an associated tank, a generator and a circuit for generating a constant frequency three-phase current of a predetermined frequency, which makes the gantry crane independent of external energy sources. Likewise, a retracting mechanism for an at least pivotable boom, possibly housed in a house, can also be arranged in the space frame.

As already explained above, the space frame can be provided at any point on the gantry crane. For example, it can also be designed as a bridge section of the gantry crane.

In such a case, it is advantageous if the space frame is provided with rails for the trolley, so that the trolley can also be moved along the space frame.

To make it easier to assemble a gantry crane, it can also be provided that the space frame is divided into several modules, with each module preferably containing a drive unit and/or a switching unit of the gantry crane, which may each be housed in a building. This makes it possible to produce prefabricated modules at the gantry crane's manufacturing site, which can be tested individually or in combination with one another and then assembled at the gantry crane's installation site. This also makes it possible to combine different gantry crane types with different drives in a modular manner without incurring significant additional construction costs.

The undercarriage of the gantry crane can, for example, be formed by a rail undercarriage, by means of which the gantry crane can be moved on rails. In order to increase the mobility and thus the efficiency of the gantry crane, a road undercarriage can be provided on the basic frame in addition to the rail undercarriage for moving the gantry crane on a road or similar. The additional road undercarriage makes it possible to remove the rail-bound nature of the gantry crane and to move the gantry crane to any point on the quay, where the rail-bound nature of the gantry crane is then restored. This significantly increases the handling capacity that can be achieved on the quay, since the berthing location of the ship no longer plays a role in the handling process. In other words, the existing handling capacity of the quay can be used optimally at all times. By arranging at least the drive for the trolley hoist in the space frame forming the bridge section, the mobility of the gantry crane by means of the road chassis is also supported, as this improves the weight distribution and the center of gravity of the gantry crane.

In principle, a common drive can be provided for both the rail chassis and the road chassis. However, it is also possible for the rail chassis and the road chassis to each have their own drive. The drive for the road chassis can preferably be a hydraulic or electric drive. It is also possible for the road chassis not to have its own drive, but for the gantry crane to be pulled by a tractor or similar when moving using the road chassis.

In order to ensure that one of the two chassis is not damaged during use, it can also be provided that the rail chassis and/or the road chassis can be lifted reversibly. The lifting can be carried out using an appropriately designed hydraulic system.

However, it is also possible for the road chassis to stand on the road at the same time as the rail chassis and preferably only the road chassis can be driven with a drive. This design has the advantage that only a single drive needs to be provided, so that the movement along the rails by means of the rail chassis is carried out by the driven wheels of the road chassis. The wheels of the road chassis can stand on the road with a predetermined contact pressure. The rail chassis can then be designed so that it can be lifted in order to move the gantry crane using the road chassis.

The basic frame of the gantry crane can have any shape. The simplest way to design a basic frame is to have four vertically aligned columns, with a road and rail chassis assembly arranged on each column, which together form the road and rail chassis.

In this case, it can be provided that the road and rail chassis assemblies of a shaft are connected to a shaft which is connected to the shaft by means of a substantially

Depending on whether the gantry crane is to be moved on rails or on the road, the rocker is then swivelled using suitable hydraulics, for example, so that one or the other chassis is in contact with the respective surface provided for it.

In order to ensure that the transition from rail to road or from road to rail can be carried out without difficulties with regard to raising and lowering the respective chassis, it is also intended that the rail wheels of the rail chassis and the road wheels of the road chassis are arranged offset from one another transversely to the direction of rail travel. This is particularly advantageous if both the rail wheels of the rail chassis and the road wheels of the road chassis are on their respective surfaces for moving the gantry crane on rails.

In order to ensure that the gantry crane can be maneuvered into its respective position without difficulty, it can also be provided that the road wheels of the road chassis can be steered in a controlled manner on at least one side of the gantry of the basic frame. The road wheels of the other legs of the basic frame or the other road chassis assemblies can then also be designed as follower wheels. However, it is also possible for each road wheel of the road chassis to be steered in a controlled manner. In order to achieve the most space-saving maneuverability of the gantry crane, it can also be provided that the steering angle of each steerable road wheel is at least 90".

Taking into account the permissible surface load at a given driving speed on the road, pneumatic tires can be provided for the road wheels of the road chassis. In principle, however, it is also possible to use any other type of wheel.

Likewise, there is basically the possibility that on each stem of the

Only one single rail wheel is provided on the basic frame. However, for better distribution of the loads, it can also be provided that at least two rail wheels are provided on each post of the basic frame, which can be combined in pairs if necessary. In this case, it is also possible for a road wheel to be arranged in such a way that it is located in the middle between two rail wheels.

In order to avoid a collision of the gantry crane, which can be moved by the road running gear, with objects on the quay, such as other cranes, stacked goods, etc., it can also be provided that the swivel axis of the boom, which can be reversibly swiveled in a vertical plane from an operating position to an inoperative position, can be moved in a vertical plane. By moving the swivel axis together with the boom in a vertical plane, the boom can not only be swiveled out of the area of mooring ships, but can even be retracted. Therefore, not only is the horizontal width of the gantry crane shortened, but the vertical height required by the gantry crane is smaller when the boom is in the inoperative position than the vertical height of a gantry crane with a boom that can only be swiveled by 90° around a swivel axis. In particular, this means that the gantry crane can remain below a 30 m line, measured from the quay in a vertical direction upwards. The ability to move the swivel axis with the boom therefore makes it significantly easier to move the gantry crane using the road chassis. The movement of the swivel axis in the vertical plane means that the swivel axis itself has an essentially perpendicular course to the vertical plane, but the movement components of the swivel axis are to be found in this vertical plane.

The swivel axis can be moved with both a vertical and a horizontal movement component, i.e. both in the vertical and horizontal direction in the vertical plane. When moving exclusively in the vertical direction, the swivel axis is moved together with the boom to reach the inoperative position of the

The boom is moved essentially vertically downwards, relative to the support plane of the gantry crane. After reaching its final non-operational position, the boom then rests essentially on the water side of the gantry crane, running parallel to the supports. When moving exclusively in a horizontal direction, the swivel axis is moved essentially horizontally backwards, relative to the water side of the gantry crane, to reach the non-operational position. After reaching the final non-operational position of the boom, the swivel axis is located, for example, in the area of the bridge section of the gantry crane. This solution can be used, for example, if the boom is not swiveled completely by 90° in the vertical plane, but only by an angle of less than 90°.

Of course, it is also possible for the swivel axis of the boom to be moved both vertically and horizontally. This can be done either one after the other or at the same time. In its non-operational position, the boom together with the swivel axis can then be located within the space spanned by the poles and crossbeams of the basic structure. The boom can be inclined to form an acute angle with the vertical or horizontal.

Likewise, the swiveling of the boom around the swivel axis and the movement of the swivel axis in the vertical and/or horizontal direction can occur sequentially or simultaneously.

It should also be noted that in each case described above, the swivel axis is moved in the opposite direction to reach the operating position of the boom.
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To guide the swivel axis during the vertical movement in particular, it can be provided that the vertically movable swivel axis can be guided on the lateral rods by suitably designed guides.

In its operating position, the swiveling boom can extend into the bridge section of the gantry crane. The trolley can also be movable along the bridge section. In order to give the gantry crane the largest possible span, it can also be provided that another boom is connected to the bridge section opposite the swiveling boom. This additional boom can be fixedly connected to the bridge section or can also be swiveling with a swivel axis that can be moved in a vertical plane if necessary.

The boom can also be designed in very different ways. For example, the boom can be designed with one or two beams. If the boom is designed with two beams, it can also be provided that the swivel axis has a guide piece which can be locked to the portal and/or the pylon for guidance after the boom has been swiveled up. The guide piece therefore takes over the guiding of the boom when it moves vertically downwards or upwards.

Advantageous embodiments are described below with reference to the drawings

explained. It shows:
20

Figure 1 is a schematic perspective view of a gantry crane according to the invention with a boom in the operating position;

Figure 2 is also a schematic view in the direction of the arrow

X in Figure 1;

Figure 3 is also a schematic view in the direction of the arrow

Y in Figure 1;
30

Figure 4 is a schematic diagram of the gantry crane according to Figure 1 with a

boom in non-operational position; and

Figure 5 is a schematic diagram of the gantry crane according to Figure 1 with a

a boom in an alternative non-operational position compared to Figure 4.

In Figures 1 to 5, a gantry crane P according to the invention is shown schematically in such a way that its essential components or assemblies can be recognized. If, for the purpose of orientation, a water or land side of the gantry crane P is mentioned, this refers to a gantry crane P standing on a quay K and ready for operation.

The gantry crane P shown in Figures 1 to 3 has a base frame 10, to which a boom 30 is pivoted about a pivot axis S. A trolley 40 can be moved along the boom 30, which can be used to raise and lower as well as to move the goods G to be handled - here containers. The base frame 10 is also provided with at least one chassis 50, by means of which it can be moved along rails (not shown). Finally, the base frame 10 is also equipped with various other installations 70 - 76, which are explained in more detail below.

As can be seen from Figures 1 to 3, the basic structure 10 has four essentially vertically running posts 12a - 12d, each of which forms the edges of an upright, imaginary cuboid. The two water-side posts 12a, 12b and the two land-side posts 12c, 12d are connected at their lower and upper ends to a head cross brace 14a, 14c that runs essentially horizontally and to a foot cross brace 14b, 14d that runs horizontally. The distance between the posts 12a, 12b and 12c, 12d that are connected to one another by the head and foot cross braces 14a - 14d is determined by the dimensions of the goods G to be handled, as can be seen from Figure 3. On the sides of the gantry crane P facing in the direction of rail travel, the two arms 12b, 12c and 12d, 12a located there are each connected to one another by a central cross brace 16 which runs essentially horizontally and is arranged in the middle.

On these sides of the gantry crane P, a diagonal strut 18 is provided, running diagonally between the poles 12b, 12c and 12d, 12a, which runs from the one connection point between the central cross strut 16 and one pole 12b to the upper end of the other pole 12c. The poles 12 - 12d, the head and foot cross struts 14a - 14d, the central cross struts 16 and the diagonal struts 18 can be constructed from a wide variety of components made of steel, for example, such as profile parts, spars, lattice parts, beams, etc. Overall, this results in a stable construction of a gantry crane P.

The two head cross struts 14a, 14c are connected to one another by a bridge section 20 that runs essentially horizontally and is aligned at right angles to the head cross struts 14a, 14c and is arranged approximately in the middle between the respective associated pair of posts 12a, 12b and 12c, 12d. The boom 30 that can be pivoted about the pivot axis S is connected to the water-side end of the bridge section 20, whereas the bridge section 20 merges into the boom 22 that is firmly connected to the bridge section 20 at the land-side end. The bridge section 20 and the boom 22 that is firmly connected to the bridge section 20 are designed as a space frame with an essentially square cross section (see Fig. 1 and 3), in the interior of which the installations 70 - 76, which are explained in more detail below, are arranged. The upper edge of the bridge section 20 is approximately aligned with the upper edges of the two head cross struts 14a, 14c.

As can also be seen from Figures 1 to 3, a vertically aligned pylon 24 is arranged on the water-side head cross strut 14a, which is attached centrally to the head cross strut 14a and guides and holds the tensioning cables of the gantry crane P (not further designated).

The pivoting boom 30, the bridge section 20 and the boom 22 that is firmly connected to the bridge section 20 are provided with guide rails for moving the trolley 40 along these components. A driver's cab F is arranged on the trolley 40, in which the operator

of the gantry crane P takes its place.

As can also be seen from Figures 1 to 3, a chassis 50 is provided on the two foot cross struts 14b, 14d, which consists of two combination chassis 52 for each foot cross strut 14b, 14d. A combination chassis 52 has a rail chassis assembly 54 and a road chassis assembly 56. As can be seen in particular from Figures 1 and 3, the rail chassis assembly 54 is formed by four aligned rail wheels 58, which are arranged in pairs on a common chassis 60 at a distance from one another. The rail wheels 58 of the rail chassis assembly 54 can be raised or lowered again by a suitable hydraulic device (not shown). The road chassis assembly 56 is, as can be seen in particular from Figure 2, arranged in the interior of the gantry crane P offset in the rail travel direction transversely to the rail chassis assembly 54. The road chassis assembly 56 consists of twin wheels 62 which are held in a chassis 64, by means of which the twin wheels 62 can be steered around a substantially vertical axis with a steering angle of approximately 90° by means of a suitable hydraulic system (not shown). The road wheels 62 are formed by air-filled tires. They are also provided with a hydraulic drive (also not shown) which is used to drive the gantry crane P both along the rails (not shown) and on the contact surface of the quay K. To move the gantry crane P along the rails, the rail wheels 58 are lowered onto the rails. The gantry crane P can then be moved along the rails by means of the road wheels 62 standing on the quay K with a predetermined contact pressure. In order to be able to move the gantry crane P along the quay K independently of the rails, the rail wheels 58 are raised and the gantry crane P is moved using the road wheels 62. After the gantry crane P has reached its new location, the rail wheels 58 are lowered back onto the rails.

As can be seen from Figure 2, inside the space frame of the

A diesel-electric energy source 70 is arranged in the bridge section 20. The diesel-electric energy source 70 consists of a diesel engine (not shown in more detail), a tank, a generator and a circuit that generates a constant frequency three-phase current of a given frequency, all of which are arranged in a house. Furthermore, the drive for the trolley hoist 72, which is also housed in a house, is provided in the space framework of the bridge section 20. Finally, the retraction mechanism 74, which is also housed in a house and serves to pivot the boom 30 around the pivot axis S, and the electrical sound system 76, which is also housed in a house, are also provided in the space framework of the bridge section 20.

In order to be able to pivot the boom 30 about the pivot axis S in order to dock a ship at the quay K, the trolley 40 is first moved into a position on the bridge section 20 or on the boom 22 that is firmly connected to the bridge section 20. The boom 30 is then pivoted about the pivot axis S in a vertical plane using the retraction mechanism 74, as shown in Figures 1 to 3. The ship can then dock at the quay K and the boom 30 can pivot back into its operating position about the pivot axis S.

If, in addition, the gantry crane P is to be moved from its previous location along the quay K to a new location using the road chassis made up of the road chassis assemblies 56, the rail chassis made up of the rail chassis assemblies 54 is raised after or at the same time as the boom 30 is pivoted. Subsequently or at the same time, the pivot axis S can be moved vertically along the water-side posts 12a, 12b downwards in the vertical pivot plane together with the boom 30 already pivoted in the vertical plane about the pivot axis S, as shown in Figure 4. In its non-operating position, the boom 30 then rests on the water side of the gantry crane P, running essentially parallel to the posts 12a, 12b.

This allows the gantry crane P to pass under the rail-mounted cranes of the quay K or the like without any of its components colliding with these cranes. Alternatively, it can be provided that the swivel axis S is moved together with the boom 30 both vertically downwards and horizontally backwards in the vertical plane, so that after the boom 30 has reached the inoperative position, it is arranged inside the gantry crane P, as can be seen from Figure 5. In this case, the boom 30 does not swivel in the vertical plane by 90° around the swivel axis S, but by an angle of less than 90°, so that it forms an acute angle with the horizontal or vertical, as can also be seen from Figure 5. This means that the gantry crane P can then be moved on the quay K again after the rail carriage 54 has been retracted (or if the rail carriage 54 has already been retracted beforehand). After reaching the new location, the swivel axis S is moved back in the vertical plane together with the boom 30 and the boom 30 is swiveled into its operating position.

It should also be noted that the processes described above - swiveling the boom 30, retracting or extending the rail carriage 54, moving the swivel axis S - can be carried out both simultaneously and sequentially.

It should also be noted that a staircase T is provided on the land-side post 12c, through which the operator can reach the cabin F of the trolley 40.

Claims (33)

Expectations 1. Gantry crane for handling goods, in particular for container handling with feeder ships, comprising a base frame (10) with at least one boom (30), with a trolley (40) that can be moved at least on the boom (30) for raising and lowering and moving the goods to be handled (G), and with a chassis (50) for moving the gantry crane (P), characterized in that at least one section of the basic framework (10) is designed as a spatial framework, in the interior of which at least the drive (72) for the lifting mechanism of the trolley (40) is arranged . 2. Gantry crane according to claim 1, characterized in that the space framework has a substantially rectangular, preferably square cross-section. 3. Gantry crane according to claim 1 or 2, characterized in that the space framework forms the bridge section (20) of the gantry crane (P), to which a further boom (30) is optionally connected. 4. Gantry crane according to one of claims 1 to 3, characterized in that the drive of the hoist of the trolley (40) is housed in a housing. 5. Gantry crane according to one of claims 1 to 4, characterized in that a combustion-powered energy source (70), possibly housed in a house, is arranged in the space framework. 6. Gantry crane according to claim 5, characterized in that the combustion-powered energy source is a diesel-electric system (70). 7. Gantry crane according to one of claims 1 to 6, characterized in that an electrical switching system (76) of the gantry crane (P), possibly housed in a house, is arranged in the space framework. 8. Gantry crane according to one of claims 1 to 7, characterized in that a retractable mechanism (74), possibly housed in a house, for a pivotable boom (30) is arranged in the space framework. 9. Gantry crane according to one of claims 1 to 8, characterized in that the space framework is provided with rails for the trolley (40). 10. Gantry crane according to one of claims 1 to 9, characterized in that the space framework is divided into several modules, wherein preferably each module accommodates a drive unit (70-74) and/or a switching unit (76) of the gantry crane (P), which are optionally each housed in a house. 11. Gantry crane according to one of claims 1 to 10, in which the chassis is a rail chassis (54), characterized in that, in addition to the rail chassis (54) on the base frame (10), a road chassis (56) is provided for moving the gantry crane (P) on a road (K). 12. Gantry crane according to claim 11, characterized in that a separate drive is provided for the rail chassis (54) and for the road chassis (56). 13. Gantry crane according to claim 11 or 12, characterized in that the rail chassis (54) and/or the road chassis (56) are retractable. 14. Gantry crane according to one of claims 11 to 13, characterized in that the road chassis (56) stands on the road (K) at the same time as the rail chassis (54) standing on rails and the road chassis (56) can be driven by a drive.
10 15. Gantry crane according to claim 14, characterized in that the road wheels (62) of the road chassis (56) rest on the road (K) with a predetermined contact pressure.
15 16. Gantry crane according to one of claims 11 to 15, in which the basic frame (10) has four substantially vertically aligned legs (12a-12d), characterized in that a road and a rail chassis assembly (56, 54) is arranged on each post (12a-12d). 17. Gantry crane according to claim 16, characterized in that a road and a rail chassis assembly (56, 54) of each arm (12a-12d) is arranged on a rocker pivotably supported on the arm (12a-12d) by means of a substantially horizontally extending axis. 18. Gantry crane according to one of claims 11 to 17, characterized in that the rail running wheels (58) of the rail chassis (54) and the road running wheels (62) of the road chassis (56) are arranged offset from one another transversely to the rail travel direction. 19. Gantry crane according to one of claims 11 to 18, characterized in that the road wheels (62) of at least two consecutive arms (12a, 12d or 12b, 12c) are steerable.
5 20. Gantry crane according to claim 19, characterized in that each road wheel (62) of the road chassis (56) is designed to be steerable with a steering angle of at least 90°.
10 21. Gantry crane according to one of claims 11 to 20, characterized in that the road wheels of the road chassis are air-filled tires (62). 22. Gantry crane according to one of claims 11 to 21, characterized in that the drive of the road chassis (56) is formed by a hydraulic drive or electric drive. 23. Gantry crane according to one of claims 16 to 22, characterized in that the rail chassis (54) is formed by at least two rail wheels (58) provided on each post (12a-12d) of the basic frame (10), whereby if necessary two rail wheels (58) are combined to form a pair. 24. Gantry crane according to claim 23, characterized in that between two pairs of rail wheels (58) at least one road wheel (62) of the associated road chassis assembly (56) is provided. 25. Gantry crane according to one of claims 1 to 24, in which the boom can be pivoted reversibly about a pivot axis (S) in a vertical plane from an operating position to an inoperative position,
characterized in that the pivot axis (S) is reversibly movable in a vertical plane. - 19 - 26. Gantry crane according to claim 25 characterized in that the pivot axis (S) is vertically movable. 27. Gantry crane according to claim 25 or 26, characterized in that the pivot axis (S) can be moved horizontally. 28. Gantry crane according to claim 26 or 27, characterized in that the pivot axis (S) can be moved horizontally and vertically approximately simultaneously. 29. Gantry crane according to one of claims 25 to 28, characterized in that the pivot axis (S) can be moved approximately simultaneously with the pivoting movement of the boom (30). 30. Gantry crane according to one of claims 25 to 29, characterized in that the pivotable boom (30) is designed with one or two booms.
20 31. Gantry crane according to one of claims 26 to 30, characterized in that the vertically movable pivot axis (S) is guided on lateral posts (12a, 12b) of the basic frame (10) by suitable guides.
25 32. Gantry crane according to claim 31, characterized in that the vertically movable swivel axis (S) in the case of a two-arm boom has a guide piece which is locked to the portal for the purpose of guiding after the boom has been swiveled up and thus takes over the guidance of the boom when the boom is lowered. 33. Gantry crane according to one of claims 25 to 32, characterized in that the pivotable boom (30) in its operating position merges into a fixed bridge section (20) of the gantry crane (P), to which a further fixed boom (22) opposite the pivotable boom (30) is optionally connected.