MOBILE CRANE WITH ADJUSTABLE COUNTERWEIGHT DEVICE

Description

[0001] The present invention relates to a mobile crane according to the preamble of claim 1.

[0002] Mobile cranes typically consist of an undercarriage with wheels or tracks, a superstructure mounted on the undercarriage to rotate around a vertical axis, a boom pivoting on the superstructure, and a counterweight device also known as superstructure ballast. The counterweight, acting as a lever arm, provides a counter-moment to the load moment in every position of the superstructure and therefore rotates with it.

[0003] While smaller mobile cranes, often referred to as taxi cranes, carry all the necessary equipment for use on construction sites, even when traveling on public roads, larger mobile cranes are not capable of this. Therefore, it is necessary to dismantle crane components, and especially the counterweight system, completely or partially for transport on public roads and reassemble them on site. Similarly, with crawler cranes, the counterweight system typically needs to be dismantled for transport and reattached to the superstructure at the work site.

[0004] It is therefore known from the prior art to provide a counterweight base plate with connecting elements for detachable connection to the superstructure, on which counterweight elements can be stacked. For this purpose, the superstructure is equipped with a ballasting device capable of lifting the counterweight assembly, comprising the counterweight base plate and the stacked counterweight elements, from the ground or a storage area on the undercarriage by means of the connecting elements and onto the superstructure. For disassembly, the counterweight base plate with the counterweight elements can be placed back on the ground or the undercarriage. For this purpose, the ballasting device typically includes one or more hydraulic ballasting cylinders that extend downwards, engage with the connecting elements of the counterweight assembly, and, by retracting, lift the counterweight assembly onto the superstructure.

[0005] In the prior art, connecting elements include cylindrical or flat mounting tubes that are rigidly connected to the counterweight base plate, for example by welding, and project vertically upwards from it. The counterweight elements have corresponding recesses through which the connecting elements protrude, so that, when stacked, the ballast cylinders can be engaged from above with the receptacles of the connecting elements, for example in combination with a rotary movement of the superstructure.

[0006] For mounting the counterweight system, it is typically placed on a storage area on the undercarriage, and the counterweight elements are stacked on the counterweight base plate. The superstructure rotates with its ballasting system over the stacked counterweight system, and the ballasting cylinders pull it towards the superstructure via the connecting elements. Due to this mounting method, the size of the mountable volume of the counterweight system is limited. In particular, the counterweight system cannot extend arbitrarily far from the vertical axis of rotation of the superstructure. The undercarriage typically has other components in this area, such as a cab, an engine housing, exhaust aftertreatment components, or similar items, preventing the counterweight system from extending into this space.The counterweight device cannot extend any closer to the vertical axis of rotation of the superstructure because the superstructure's steel frame is located there. If the mass of the counterweight is to be increased further, this could only be achieved, while maintaining the same volume, by increasing the specific weight of the counterweight elements. However, this would make the production and procurement of the counterweight elements complex and expensive.

[0007] From DE 20 2014 008 661 U1, it is known to increase the counterweight moment by changing the distance of the ballast cylinders to the upper carriage's axis of rotation. This distance can be fixed before the counterweight is set up. However, a disadvantage of this solution is that the counterweight radius cannot be changed during crane operation and therefore cannot be adapted to the prevailing site conditions, for example, during a specific rotational movement. Furthermore, this creates an additional tipping criterion, particularly for mobile cranes with a variable outrigger base.

[0008] Other solutions, such as that described in DE 10 2016 009 013 A1, use pivoting counterweight base plates. However, the installation of such counterweight devices is complex, as the counterweights have their own ballast cylinders to press themselves against the superstructure from below. Therefore, a hydraulic connection to the ballast cylinders of the counterweight device must be established before the counterweight is installed. Furthermore, secure and stable mounting of the counterweight device on the ballast cylinders must be ensured to prevent it from tipping over when being raised. Moreover, such solutions are more suitable for larger mobile cranes that use towers of stacked counterweight elements, making the use of standardized counterweight elements more advantageous.

[0009] Furthermore, a mobile crane with a connectable counterweight device is known from EP 3 878 795 A1, which forms the general initial situation defined in claim 1 according to the preamble, but does not disclose any adjustment in the ballasted state.

[0010] Against this background, the present invention aims to provide a counterweight device for generic mobile cranes which allows a change in the generated counter-moment during operation and is particularly suitable for smaller mobile cranes with fewer counterweight elements.

[0011] According to the invention, this problem is solved by a mobile crane having the features of claim 1. Advantageous embodiments of the invention are described in the dependent claims and the following description.

[0012] According to the invention, a mobile crane is proposed which comprises a movable undercarriage, a superstructure rotatably mounted on the undercarriage about a vertical axis of rotation, and a counterweight device. In particular, a boom, for example a telescopic boom, is pivotally connected to the superstructure. The superstructure includes a ballasting device to which the counterweight device can be detachably coupled in order to generate a counter-moment opposing the lifted load during operation. The counterweight device comprises a counterweight base plate and at least one connecting element for lifting the counterweight device and for coupling the counterweight device to the ballasting device of the superstructure. The at least one connecting element extends from and is connected to the counterweight base plate. In particular, it extends substantially perpendicular to the counterweight base plate.The ballasting device comprises at least one first arm, which is pivotably mounted on the superstructure about a vertical axis of rotation and allows adjustment of the distance between the counterweight device and the superstructure axis of rotation when ballasted. The counterweight device is directly or indirectly connected to the at least one first arm, such that a movement of the first arm results in a movement of the counterweight device.

[0013] According to the invention, the first arm, in its ballasted state, is connected to the counterweight base plate via a pivotable coupling element. In the case of multiple first arms, each first arm is connected to a corresponding coupling element. The at least one coupling element is pivotably mounted relative to the associated first arm and the counterweight base plate such that the counterweight base plate can be adjusted or changed radially to the upper carriage axis in a linear movement by simultaneously pivoting the first arm and the coupling element.

[0014] The inventive combination of a first arm and a coupling element, both of which are pivotable, makes it possible to change the counterweight radius not by pivoting the counterweight on a circular path, but by a linear movement of the counterweight device radially to the vertical axis of rotation of the superstructure, i.e., parallel to a longitudinal axis of the superstructure. This allows the counter-moment generated by the counterweight device to be flexibly adjusted during crane operation, and in particular, does not require any additional space to the side of the superstructure or the counterweight device, since no counterweight is pivoted laterally. This is a significant advantage, especially in confined construction site environments.

[0015] Furthermore, the undercarriage requires only a single storage device or area for the counterweight assembly, as the counterweight radius is adjusted during operation while ballasted, not during counterweight setup. This allows the undercarriage to have an optimized, space-saving design.

[0016] Preferably, the at least one first arm is actively pivotable via at least one actuator, in particular a hydraulic cylinder. The adjustment of the counterweight device via the at least one actuator can preferably be carried out centrally via a crane control system, whereby the operator can preferably make the corresponding inputs from the driver's cab.

[0017] For the sake of simplicity, the following text refers only to "the connecting element," but this should be understood to mean at least one connecting element, i.e., possibly including any other existing connecting elements. Furthermore, absolute terms such as "vertical" and "horizontal" always refer to the case where the mobile crane is standing on a level, horizontal surface.

[0018] Preferably, the at least one connecting element is designed as a sheet metal construction, particularly with a substantially flat shape. Such a sheet metal construction is easier to manufacture than, for example, a cylindrical receiving tube and can be produced with a suitable thickness to withstand the various loads acting along and across its longitudinal axis.

[0019] The connecting element can include a lifting element for attaching a lifting sling (e.g., a chain or rope) of a hoist for lifting the counterweight base plate. This allows the counterweight base plate, along with the connecting element(s), to be lifted by an auxiliary crane or the mobile crane being rigged itself and positioned, for example, on a storage area of ​​the undercarriage. Preferably, the lifting sling is formed by a recess in the connecting element. Hook elements, projections, or similar features are also conceivable for attaching the lifting sling.

[0020] In one possible embodiment, the counterweight device comprises two spaced-apart connecting elements for coupling the counterweight device to the ballast system. Accordingly, in this embodiment, the ballast system has two pivotable first arms, which can be pivoted jointly or synchronously to adjust the distance of the counterweight device from the upper carriage's axis of rotation. The use of multiple connecting elements results in a stable connection of the counterweight device to the upper carriage. Preferably, exactly two connecting elements are provided.

[0021] The connecting elements can be arranged at a particular distance from the center of gravity of the counterweight base plate or from the longitudinal axis of the superstructure. The counterweight device is preferably designed symmetrically with respect to a vertical central plane running through the longitudinal axis of the superstructure.

[0022] In another possible embodiment, the first arms are arranged laterally on the ballasting device, in particular on a ballast frame connected to or formed on the superstructure. Furthermore, the first arms are pivotable in opposite directions of rotation for linear adjustment of the distance of the counterweight device from the superstructure's axis of rotation; that is, one of the first arms pivots clockwise while the other first arm simultaneously pivots counterclockwise.

[0023] The synchronized, actuator-based adjustment of the first arms can be implemented in different ways.

[0024] In one possible embodiment, each of the first arms is pivotable via its own hydraulic cylinder. In this case, suitable synchronization of the pivoting movements must be ensured. This can be achieved by synchronizing the hydraulic cylinders and their associated control system. This can be realized, for example, using linear encoders in the cylinders, which provide their signals to a control system that synchronizes the hydraulic cylinders accordingly, for example, via electrically actuated valves. In this case, the static load cases can be reduced (no asymmetry needs to be assumed).

[0025] In an alternative embodiment, only one of the first arms is pivotable via a hydraulic cylinder, and the first arms are mechanically coupled to each other via a gear drive such that they pivot synchronously when the hydraulic cylinder is actuated. In this context, the term "gear drive" means that at least two gears are provided. These can be coupled to each other, to other gears, or to each other by a connecting element such as a chain. In the latter case, it could also be called a chain drive.

[0026] Due to the mechanical coupling of the first arms, synchronized control of multiple actuators is not required. The aforementioned gear drive preferably comprises gears non-rotatably connected to the first arms, which are mechanically coupled to each other via a connecting element. The coupling is not direct, as otherwise the first arms would move in the same direction. Therefore, at least one additional intermediate gear is provided to reverse the direction of rotation of one of the first arms. This gear is, in particular, freely rotatable on the superstructure and meshes with the non-rotatable gear of one of the first arms. The non-rotatable gears are, in particular, arranged collinearly with the axes of rotation of the arms.

[0027] The connecting element is preferably a chain, so the synchronization drive is designed as a chain drive. However, a belt or one or more gears can also be used as the connecting element.

[0028] When the hydraulic cylinder is actuated, the gear fixed to this first arm rotates with the arm and thereby moves the connecting element, which, for example, moves a gear freely rotatable on the upper structure, which in turn meshes with a gear fixed to the other first arm. This results in both arms performing a synchronized, counter-rotating pivoting motion.

[0029] In another possible embodiment, the ballasting device is designed to lift the counterweight assembly from a storage area on the undercarriage and place it there. This storage area may be located behind the driver's cab of the undercarriage. The at least one connecting element has a coupling section at one end opposite the counterweight base plate (i.e., facing the superstructure or the ballasting device), through which a detachable mechanical connection to the ballasting device can be established. The coupling section may include a receptacle into which a lifting device of the ballasting system, in particular a ballasting cylinder, can be inserted to establish a connection for lifting the counterweight assembly.

[0030] In another possible embodiment, the ballasting device comprises at least one hydraulic ballasting cylinder, which can be detachably engaged with the coupling section of the at least one connecting element. The coupling section includes a receptacle into which a coupling piece of the ballasting cylinder can be inserted, in particular by rotating the superstructure about its axis of rotation. The ballasting cylinder has, in particular, a piston rod that can be extended downwards from the ballasting device and at the end of which the coupling piece is located. The latter can be part of the piston rod of the ballasting cylinder, i.e., formed integrally with it, or a separate component connected to it.

[0031] The receptacle for the coupling section is open, in particular, upwards and on at least one side. The receptacle can be designed to allow lateral insertion (e.g., following a circular motion) of the ballast cylinder and, in the connected state, to positively block movement of the ballast cylinder out of the recess in a vertical direction. In the raised state, the counterweight device can rest on or be suspended from the coupling piece of the at least one ballast cylinder via the recess of the at least one connecting element.

[0032] The coupling piece can be locked in the recess, for example by means of a specially provided locking device. Alternatively or additionally, the locking can simply be achieved by a mechanical stop, which blocks further movement of the coupling piece relative to the coupling section.

[0033] In another possible embodiment, the receptacle and / or the coupling piece has a rounded, for example convex, contour, which allows for articulated movement of the coupling piece within the receptacle under load. Such a connection allows the connecting element to pivot relative to the ballast cylinder along various degrees of freedom, for example, to compensate for movement of the ballast cylinder along a circular path when the first arm pivots and to allow for linear displacement of the counterweight device.

[0034] In another possible embodiment, the ballasting cylinder comprises a cylindrical shell and a piston slidably within it, with a piston rod at the free end of which the coupling piece is located. The piston is rotatably mounted in the cylindrical shell about the longitudinal axis of the piston rod. This allows the coupling piece, which is located in the receptacle of the connecting element, to rotate relative to the respective first arm during a pivoting movement, ideally in such a way that it does not rotate relative to the receptacle of the connecting element, thus reducing or eliminating frictional forces arising from relative movement in the receptacle.

[0035] The ballasting cylinder can be actuated by a hydraulic system, wherein the ballasting cylinder and the hydraulic system are designed such that in the ballasted state the piston rod is blocked in a locking mode against extension and rotation, while in an adjustment mode a rotation of the piston rod relative to the cylinder shell is possible at the same extension position.

[0036] In locking mode, the ballast cylinder is hydraulically blocked, while in adjustment mode, the piston rod can be rotated around its longitudinal axis to adjust the counterweight radius. In adjustment mode, the piston rod is preferably extended further than in locking mode. Preferably, the counterweight device is pressed against the superstructure by the ballast cylinders and fixed there by hydraulic locking (locking mode). The hydraulic locking can occur, for example, after a defined contact pressure is reached. An additional mechanical connection, for example, by one or more bolted connections, can be optionally provided. Due to the resistance generated by the hydraulic locking, the ballast cylinders must first be released to adjust the counterweight radius.If the counterweight device needs to be adjusted, the hydraulic lock is released and the piston rods of the ballast cylinders are extended slightly. The free rotation of the piston rods relative to the cylinders prevents any relative movement to the mounting points of the connecting elements when the first arms are pivoted.

[0037] In another possible embodiment, at least one second counterweight element is provided, stackable on the counterweight base plate, and has at least one recess through which the at least one connecting element projects when in the lowered state. The second counterweight element is particularly plate-shaped. Several second counterweight elements can be provided and stackable on the counterweight base plate.

[0038] The connecting element includes, in particular, the coupling section described above for coupling with a corresponding coupling piece of a ballast cylinder. Preferably, the coupling section or its receptacle is arranged such that, in the connected state, it lies within the recess of a second counterweight element. Preferably, the recess is designed such that the coupling piece of the ballast cylinder can be positioned next to the coupling section of the connecting element within the recess and inserted into the coupling section or its receptacle by rotating the superstructure about its vertical axis of rotation. The ballast cylinder then describes a circular path and moves laterally into the receptacle. The recess of the corresponding second counterweight element must therefore be wider to allow such a circular movement when coupling the ballast cylinder to the connecting element.

[0039] The recess of the second counterweight element can have a mechanical stop against which the coupling piece of the ballast cylinder abuts in a locking position where the ballast cylinder and the connecting element are correctly coupled. The stop can be formed by a wall of the recess itself, resulting in a particularly simple embodiment. Alternatively, the stop can also be implemented by a separate component arranged in the recess.

[0040] In another possible embodiment, a measuring device is provided for detecting the ballast status of the mobile crane, which is transmitted to a control unit of the mobile crane, in particular to a load moment limiter. This allows the ballast status to be continuously monitored and any potential tipping of the crane to be detected and prevented at an early stage. The measuring device preferably comprises at least one sensor by means of which the instantaneous slewing angle of the at least one first arm can be detected.

[0041] In another possible embodiment, the at least one first arm of the ballasting device is pivotally connected to a second arm, the second arm being pivotably mounted on the first arm about a vertical axis of rotation. If several first arms are provided, each of these first arms is pivotably connected to a second arm about a vertical axis of rotation. In this case, the at least one connecting element of the counterweight device can be coupled to the at least one second arm. Thus, the counterweight device is not connected to the first arm(s), but to the second arm(s). Preferably, the coupling is achieved via ballasting cylinders, as described above. In this case, the at least one second arm has a ballasting cylinder to lift the counterweight device via the at least one connecting element and connect it to the ballasting device.

[0042] In another possible embodiment, the first and second arms are coupled in such a way that when a first arm pivots about its axis of rotation, the second arm, to which it is articulated, automatically pivots about its axis of rotation. The two arms are thus mechanically coupled and perform a synchronized pivoting movement about their respective axes of rotation, particularly in opposite directions. The movements of the arms are preferably synchronized such that their pivot angles or angular velocities are in a defined ratio to each other. This makes it possible to coordinate the two arms so that a ballast cylinder arranged on the second arm performs a linear movement while each arm performs a pivoting movement.If two connecting elements and thus two pairs of first and second arms are provided, this results in a linear movement of the counterweight device parallel to the longitudinal axis of the upper carriage, with the individual movements of the respective arms taking place on circular paths.

[0043] The synchronization of the coupled first and second arms can be achieved in different ways.

[0044] In one possible embodiment, the first and second arms are connected via a second hydraulic cylinder. The first hydraulic cylinder, which pivots the first arm relative to the superstructure, and the second hydraulic cylinder, which pivots the second arm relative to the first arm, are controlled synchronously such that the angular velocities of the first and second arms are in a defined ratio to each other during pivoting. The coordination or synchronization of the two arms is thus achieved by synchronizing several hydraulic cylinders.

[0045] In an alternative embodiment, the first and second arms are mechanically coupled to each other via a gear drive such that they pivot synchronously when the hydraulic cylinder pivoting the first arm relative to the superstructure is actuated. Similar to the previously described mechanical coupling of two first arms, the first and second arms can also be synchronized via a mechanical coupling.

[0046] The gear drive mechanically synchronizing the first and second arms preferably comprises a first gear fixed to the superstructure and a second gear fixed to the second arm, which are coupled to each other by a connecting element, in particular a chain. Consequently, when the second arm rotates relative to the first arm, the second gear rotates with the second arm. Here too, a belt or an arrangement of further gears (i.e., at least one additional gear) could be provided instead of a chain.

[0047] The second gear is arranged collinearly with the axis of rotation of the second arm and moves with it when the first arm pivots. This results in a relative rotation of the second gear with respect to the upper structure. Due to the overall rotationally fixed mounting of the first gear and the coupling via the connecting element, when the first arm pivots in a specific direction, the second arm, which is rotationally fixed to the second gear, automatically rotates in the opposite direction.

[0048] If two first arms are provided, they can be mechanically coupled to their respective second arms via gear drives and also mechanically coupled to each other, as described above. Alternatively, all or some of the arms can be pivotable via hydraulic cylinders. The following combinations are therefore possible: The first arms are mechanically coupled to each other and to their respective second arms via gear drives. This means that only one of the first arms can be pivoted via a hydraulic cylinder or adjusting cylinder, while the other first arm and the two second arms move automatically via the mechanical gear drives. Alternatively, the first arms can be mechanically coupled to each other via a gear drive, with the second arms each being moved by hydraulic cylinders. This variant is less preferred, however, because the movements of the second arms would have to be complexly coordinated with the first arms by appropriately controlling the various hydraulic cylinders. Another option is for both first arms to be pivoted via their own hydraulic cylinders, which are coordinated as described above, and the first arms are mechanically coupled to the second arms via gear drives.Both first arms can be pivoted via their own hydraulic cylinders, and the second arms are also moved via hydraulic cylinders, meaning that at least four hydraulic cylinders need to be coordinated.

[0049] In the embodiments described above, a linear movement of the counterweight base plate is achieved by converting a pivoting movement of the first arm (i.e., a circular trajectory of the end of the first arm) into a linear movement of a free end of the second arm via a second arm by synchronizing the pivoting movements. Here, the second arm (or arms) consequently represents the aforementioned pivotable coupling element, and both the pivoting movement of the first arm and the pivoting movement of the coupling element occur about a vertical axis of rotation.

[0050] Another solution for achieving linear movement of the counterweight base plate parallel to the longitudinal axis of the superstructure is realized in an alternative embodiment by pivotally connecting the at least one connecting element of the counterweight device to the counterweight base plate. This at least one connecting element can be coupled to the at least one first arm, in particular via a ballast cylinder arranged on the first arm. Thus, no second pivoting arm is provided; instead, the counterweight device is directly connected to the at least one first arm.

[0051] In this embodiment, the pivoting movement of the first arm is not achieved by a counter-rotating second arm, but rather by the fact that the at least one connecting element is pivotably mounted and can thus move sideways when the first arm pivots. Here, the at least one connecting element itself constitutes the pivotable coupling element, which is connected to the counterweight base plate.

[0052] In another possible embodiment, as described above, two connecting elements are provided, each pivotally connected to the counterweight base plate about a horizontal pivot axis. When the first arms are pivoted to linearly adjust the counterweight device, the connecting elements pivot laterally, in particular perpendicular to the direction of movement of the counterweight device or to the longitudinal axis of the superstructure, in order to compensate for the circular movements of the first arms. Thus, adjusting the counterweight radius involves a combination of a pivoting movement about a vertical axis and a further pivoting movement about a horizontal axis.

[0053] As described above, both first arms can be driven by a hydraulic cylinder each, or the first arms can be mechanically coupled together, so that only one of the first arms needs to be driven by an actuator or hydraulic cylinder.

[0054] The pivoting of the connecting elements relative to the first arms inevitably results in a relative movement between the coupling pieces of the ballast cylinders, which are arranged particularly at the ends of the first arms, and the receptacles of the coupling sections of the connecting elements. This relative movement can be countered in various ways.

[0055] In one possible embodiment, the connecting elements comprise a base body pivotably connected to the counterweight base plate. A pivoting element is pivotably attached to the end of this base body facing the first arm or the ballasting device. This pivoting element has a coupling section through which a connection to the first arm of the ballasting device can be established. The pivoting element is preferably pivotally mounted to the base body about a horizontal pivot axis to compensate for any tilting of the connecting elements and thus ensure a constant alignment or inclination of the coupling section relative to the first arm. The coupling section includes, in particular, as described above, a receptacle for coupling with a ballasting cylinder of the first arm.

[0056] Alternatively, as previously explained, a rounded or convex connection between the receptacle and the coupling piece could be used to minimize friction of the coupling piece within the receptacle. With such a design, a pivoting swivel element on the connecting element is not required.

[0057] In another possible embodiment, the connecting elements are each pre-tensioned into a vertical or inwardly pivoted home position by a return element, in particular a spring. The return elements thus press the connecting elements inwards, so that when the counterweight device is adjusted, the connecting elements pivot outwards against the return forces of the return elements, or "deviate." The return elements can be designed as very strong springs, for example, as disc springs.

[0058] In another possible embodiment, the connecting elements are pivotably connected to the counterweight base plate in both directions relative to the vertical by a maximum pivot angle. The maximum pivot angle, or its magnitude, is preferably less than 20° (i.e., -20° < α < 20°) and particularly preferably less than 15° (i.e., -15° < α < 15°). In this embodiment, the recesses of any additional counterweight elements placed on the counterweight base plate, through which the connecting elements protrude, must be widened accordingly so that the connecting elements do not collide with the walls of the recesses during the aforementioned pivoting movement.

[0059] Further features, details and advantages of the invention will become apparent from the exemplary embodiments explained below with reference to the figures. The figures show: Figure 1: a perspective view of the superstructure of the mobile crane according to a first embodiment; Figure 2: a perspective view of the superstructure of the mobile crane according to a second embodiment; Figure 3: a perspective view of the superstructure of the mobile crane according to a third embodiment; Figures 4-7: perspective views of the third embodiment in different positions when adjusting the counterweight device; and Figure 8: a schematic view of the superstructure of the mobile crane according to a fourth embodiment.

[0060] The Figure 1Figure 1 shows a perspective view of the superstructure 14 of the mobile crane 10 according to a first embodiment, showing only the steel structure of the superstructure 14 without any covers and without the boom (which is in particular a telescopic boom) in order to reveal the relevant components. The superstructure 14 is rotatably mounted about a vertical superstructure pivot axis 13 on a mobile undercarriage, which is also not shown.

[0061] The superstructure 14 has a ballasting device 20 at its rear with a ballast frame 22, to which a counterweight device 50, also referred to as superstructure ballast, can be detachably attached to counteract a load lifted by the boom and prevent the mobile crane 10 from tipping over. The counterweight device 50 comprises a counterweight base plate 52, on which one or more counterweight plates can be placed or stacked (for clarity, only the counterweight base plate 52 is shown in the present figures). The ballast frame 22 can support a winch 24.

[0062] In the embodiments discussed here, the ballasting device 20 comprises two hydraulic ballasting cylinders 26 for lifting the counterweight device 50 from or placing it onto a storage area of ​​the undercarriage. After lifting the counterweight device 50 onto the ballast frame 22, these can either be bolted together or the ballasting cylinders 26 press the counterweight device 50 against the ballast frame. In the latter variant, which is implemented in the embodiment shown here, the ballasting cylinders 26 are hydraulically locked after reaching a predetermined contact pressure, so that the counterweight device 50 is securely held against the superstructure 14. The ballasting cylinders 26 comprise pistons slidably mounted in a cylinder shell, with a piston rod that projects downwards towards the undercarriage or counterweight device 50.

[0063] To mount the counterweight device 50, it is stacked on the undercarriage 12. The superstructure 14, with its ballasting device 20, rotates over the counterweight device 50, couples to it, and the ballasting cylinders 26 then pull it to the superstructure 14, where it is held during crane operation.

[0064] The counterweight device 50 is coupled to the ballast cylinders 26 via two connecting elements 70 projecting vertically upwards from the counterweight base plate 52. At their upper ends, facing away from the counterweight base plate 52, these connecting elements 70 have coupling sections for reversible coupling with extendable coupling pieces 27 of the ballast cylinders 26, which are located at the lower ends of the piston rods of the ballast cylinders 26. The additional counterweights, which can be placed on the counterweight base plate 52, have corresponding recesses through which the connecting elements 70 protrude. These counterweights are thus placed on the counterweight base plate 52 from above and are thereby "threaded" onto the connecting elements 70, so that, in particular, the end regions of the connecting elements 70 with the coupling sections protrude upwards or remain accessible in some other way.

[0065] In the embodiments shown here, the connecting elements 70 are manufactured as sheet metal constructions with a flat base shape and can therefore also be referred to as connecting blades or blades. The coupling sections of the connecting elements 70 comprise a centrally arranged receptacle in the form of an upwardly open, clamp-shaped recess 76, into which a specially shaped (in particular mushroom-shaped) coupling piece 27 of the corresponding ballast cylinder 26 can slide laterally. In the final position, in which the counterweight device 50 can be safely lifted, the coupling piece 27 is located completely within the recess 76, the shape of which enables a positive-locking lifting of the counterweight device 50 by sliding in the ballast cylinders 26, since the coupling piece 27 cannot slide upwards out of the recess 76.The coupling of the extended ballast cylinders 26 with the connecting elements 70 is effected by a rotation of the upper carriage 14 about its vertical axis of rotation 13.

[0066] In order to be able to adjust the distance of the counterweight device 50 from the superstructure pivot axis 13 along the longitudinal axis of the superstructure (i.e., radially or perpendicular to the superstructure pivot axis 13) during crane operation, i.e., in the ballasted state, the ballast frame 22 has, in all embodiments discussed here, two pivot arms laterally, referred to here as first arms 31, each of which is pivotably connected to the ballast frame 22 about a vertical first pivot axis 33. The coupling of the counterweight device 50 to the ballasting device 20 is effected directly or indirectly via the pivotable first arms 31, which are pivoted about their pivot axes 33 to change the counterweight radius.Since the ends of the first arms 31 move along circular paths, according to the invention further pivotable coupling elements are provided, which are arranged between the counterweight base plate 52 and the first arms 31 and ensure that, despite the pivoting movements of the first arms 31, an overall linear movement of the counterweight device 50 along the longitudinal axis of the superstructure results.

[0067] In the Figure 1In the illustrated first embodiment, this linear movement is made possible by attaching a further pivot arm, designated as a second arm 32, to each end of the first arms 31. The second arms 32 are pivotably connected to the first arms 31 about a second vertical axis of rotation 34. In this embodiment, the second arms 32 represent the aforementioned pivotable coupling elements. The ballast cylinders 26 are located at the free ends of the second arms 32, enabling coupling with the connecting elements 70 of the counterweight device 50.

[0068] When the counterweight device 50 is retracted (movement in the direction of the upper carriage pivot axis 13), the first arms 31 pivot from the one in the Figure 1The first arms 31 pivot outwards in the position shown, while simultaneously the second arms 32 pivot inwards. The first two arms 31 pivot in opposite directions, as do the second two arms 32. The first and second arms 31, 32 on one side of the ballast frame 22 also pivot in opposite directions. This superposition of two opposing pivoting movements about two vertical axes 33, 34 per side results in an overall linear movement of the ballast cylinders 26 and thus of the entire counterweight device 50. During this movement, the connections between the ballast cylinders 26 and the connecting elements 70 remain under constant load.

[0069] In the exemplary embodiment of the Figure 1Both first arms 31 can be pivoted via a hydraulic adjusting cylinder 36 each. The adjusting cylinders 36 are articulated to both the superstructure 14 and the first arms 31, the first arms 31 being able to have laterally projecting lugs 37 for this purpose (see Figure 1). Fig. 2 ), on which the adjusting cylinders 36 are mounted. The two adjusting cylinders 36 are synchronously controlled via a hydraulic system and a control unit such that a parallel but opposite pivoting movement of the first arms 31 results. Suitable sensors, such as linear encoders, can be provided in or on the adjusting cylinders 36 to synchronize them and transmit their signals to the control unit.

[0070] In principle, the second arms 32 could also be pivoted relative to the first arms 31 via their own adjusting cylinders, which are articulated to the first and second arms 31, 32. Here, too, suitable synchronization with each other and with the adjusting cylinders 36 of the first arms 31 would have to be ensured.

[0071] In the exemplary embodiment of the Figure 1 In contrast, the second arms 32 are mechanically coupled to the first arms 31, so that the second arms 32 automatically rotate about their axes of rotation 34 when the first arms 31 are pivoted. In this embodiment, the mechanical coupling is achieved via gear or chain drives. The following discussion refers to one side of the ballasting device 20 and thus to one of the two pairs of first and second arms 31, 32.

[0072] A first gear 41 is fixed to the ballast frame 22, i.e., immovably mounted, and collinear with the first axis of rotation 33. Therefore, if the first arm 31 pivots, the first gear 41 does not rotate with it. A second gear 42 is fixed to the end of the second arm 32 that points towards the first arm 31 and is arranged collinearly with the second axis of rotation 34. If the second arm 32 rotates relative to the first arm 31, the second gear 42 also rotates relative to the first arm 31. The two gears 41 and 42 are coupled to each other via a chain 43 (connecting element). If the first arm 31 is pivoted about the first axis of rotation 33 by means of the adjusting cylinder 36, it also pivots about the fixed first gear 41. Due to the mechanical coupling via the chain 43, this pivoting movement of the first arm 31 drives the second arm 32. This pivots in the opposite direction to the first arm 31 around the second axis of rotation 34.

[0073] The first gear 41 has a larger diameter than the second gear 42, resulting in a defined gear ratio. This causes the second arm 32 to rotate about the second axis 34 at a higher angular velocity than the first arm 31 about the first axis 33. This is necessary to achieve an overall linear motion of the ballast cylinder 26. The first gear 41 can therefore be designed as a large gear and the second gear 42 as a pinion.

[0074] The pivoting movement of the second arm 32 causes the ballast cylinder 26 to rotate relative to the associated connecting element 70. This would result in relative movement between the coupling piece 27 and the receptacle 76, leading to increased friction. To avoid this, the piston rods of the ballast cylinders 26 can be rotatably mounted in the cylinder housings about their longitudinal axes. Thus, no relative movement between the coupling pieces 27 and the receptacles 76 needs to be assumed. However, in the absence of other fastening elements, it is necessary for the ballast cylinders 26 to press the counterweight device 50 against the ballast assembly 20 during crane operation. For this purpose, they are hydraulically locked (locking mode) after sufficient contact pressure has been reached.In order to adjust the counterweight radius against this friction by rotating the piston rods of the ballast cylinders 26, the ballast cylinders 26 must be unlocked (i.e., the hydraulic lock must be removed), the piston rods extended slightly downwards, and only then, in the position thus achieved, the new counterweight radius must be set (adjustment mode).

[0075] The counter-moment generated by the counterweight device 50 can be monitored by sensors, which transmit the data to a load moment limiter of the mobile crane 10. This can be done by detecting the slew angles of the first and / or second arms 31, 32 and / or by directly measuring the distance of the counterweight device 50 from the superstructure 14.

[0076] As an alternative to using two synchronized adjusting cylinders 36 to pivot both first arms 31, only a single adjusting cylinder 36 can be provided and the two first arms 31 mechanically coupled to each other. A corresponding second embodiment is described in the Figure 2 shown in a perspective view of the upper structure 14. Here, the two first arms 31 are mechanically coupled to each other via a gear or chain drive, whereby only one of the two first arms 31 can be pivoted via an adjusting cylinder 36 and the other first arm 31 moves automatically and synchronously.

[0077] In the Figure 2 Three embodiments are shown. Adjustment via two adjusting cylinders 36 and adjustment via the chain 49 are shown. It would also be possible to use the chain 49 as a means of synchronizing the adjusting cylinders 36.

[0078] A first gear 45 is non-rotatably connected to one of the first arms 31 (for example, the arm 31 pivotable by the adjusting cylinder 36) and is arranged collinearly with respect to the first axis of rotation 33. In the embodiment shown here, in which the first and second arms 31, 32 are also coupled to each other via a chain drive, the gear 45, which is non-rotatably mounted on the first arm 31, can be arranged above and collinearly with the gear 41, which is non-rotatably mounted on the superstructure 14, and can, for example, be guided through the stationary gear 41 to the first arm 31 via a hollow shaft. When the first arm 31 pivots, the gear 45 rotates relative to the gear 41, which is non-rotatably mounted on the superstructure 14.

[0079] A second gear 46 is non-rotatably connected to the other first arm 31 and is also arranged collinearly with its first axis of rotation 33 and the gear 41 located there, which is non-rotatably connected to the upper carriage 14. It essentially represents the counterpart to the first gear 45.

[0080] A third gear 47 is freely rotatable on the upper carriage 14 next to the second gear 46 and is coupled to the first gear 45 via a connecting element in the form of a chain 49. A fourth gear 48 sits on a common shaft with the third gear 47 for transmission purposes (the latter is in the Figure 2(concealed by the fourth gear 48) and rotates with it. It has a larger diameter than the third gear 47 and meshes with the second gear 46, which also has a larger diameter compared to the first gear 45. When the first arm 31 is pivoted via the adjusting cylinder 36, the first gear 45 and, due to the coupling via the chain 49, also the third gear 47 rotate with it. Via the fourth gear 48, the second gear 46, which is fixedly connected to the other first arm 31, is thereby rotated in the opposite direction to the first gear 45, so that both first arms 31 pivot in opposite directions at the same angular velocity. Due to the couplings of the first and second arms 31, 32 via further chain drives, the second arms 32 also pivot synchronously.

[0081] In the Figure 2For clarity, the synchronization drive for coupling the two first arms 31 is shown on the top side of the ballast frame 22. However, the synchronization drive can also be located elsewhere, for example, within the steel structure of the ballast frame 22 or on the underside. This also applies to the gearboxes coupling the first and second arms 31, 32.

[0082] The adjusting cylinder 36 can also be located in a different position or drive the first arm 31 in a different way. Another possibility is in the Figure 3As shown (this is conceivable for all embodiments shown here), the adjusting cylinder 36 is pivotally connected to the ballast frame 22 and to a gear 60 acting as a coupling gear. The coupling gear 60 drives the first and second gears 45, 46, which are non-rotatably connected to the first arms (in this embodiment via a chain 48 connected to the first gear 45 and a gear located below the coupling gear 60 on a common shaft, meshing with the second gear 46, possibly with a suitable gear ratio).

[0083] The Figure 2This shows a kind of combination of both embodiments for synchronizing the first arms 31, since the first arms 31 are mechanically coupled to each other via the chain drive and two adjusting cylinders 36 are shown at the same time. However, in practice, usually only one of these two adjusting mechanisms will be used (i.e., either two synchronized adjusting cylinders 36 or one adjusting cylinder 36 and a chain drive).

[0084] The Figure 3-8 show an alternative way to convert the pivoting movement of the first arms 31 into a linear movement of the counterweight device 50 parallel to the longitudinal axis of the upper carriage.

[0085] A third embodiment is shown here in the perspective view of the Figure 3 shown with a view to the counterweight device 50 attached to the ballast device 20. This embodiment differs from those of the Figure 1 and2 by not providing a second arm 32, but by arranging the ballast cylinders 26 directly at the free ends of the first arms 31.

[0086] To compensate for the circular movement of the ballast cylinders 26, the connecting elements 70 are not rigidly connected to the counterweight base plate 52, but are pivotable about a horizontal pivot axis 73. When the first arms 31 pivot laterally, changing the lateral distance of the ballast cylinders 26 to the longitudinal axis of the superstructure, the tilting connecting elements 70 pivot along with the cylinders or deflect to the side accordingly.

[0087] To ensure a stable connection of the coupling pieces 27 of the ballast cylinders 26 in the receptacles 76 of the connecting elements 70, the connecting elements 70 are not formed in one piece as in the previously discussed embodiments, but comprise a base body 72 pivotably connected to the counterweight base plate 52, at the end of which facing the first arm 31 a further pivoting body 74 is pivotably mounted about a horizontal pivot axis 75. The pivoting body 74 has the coupling section with the receptacle 76 for the ballast cylinder 26.

[0088] On the one hand, the pivoting element 74 compensates for the tilting movement of the base body 72, thus ensuring that no relative pivoting movement occurs between the receptacle 76 and the coupling piece 27. In combination with the possibility, described above, of mounting the piston rods of the ballast cylinders 26 so as to be rotatable in an adjustment mode, any relative movement between the receptacle 76 and the coupling piece 27 can be prevented. On the other hand, the pivoting element 74 can be designed such that it automatically aligns itself into a vertical position by gravity. For this purpose, the pivot axis 75 can be arranged in an upper region of the pivoting element 74, so that the center of gravity is located below the pivot axis 75. This allows the coupling piece 27 of the ballast cylinder 26 to be coupled to the vertically oriented coupling section of the connecting element 70 as usual.

[0089] The Figure 4-7show the exemplary embodiment of the Figure 3 in four different positions of the counterweight device 50 during a movement from a minimum to a maximum counterweight radius. In the Figure 4 The first arms 31 are fully folded forward and the counterweight base plate 52 assumes a minimal distance to the upper carriage pivot axis 13. The base bodies 72 of the connecting elements 70 are pivoted inwards (i.e., towards the longitudinal axis of the upper carriage).

[0090] By laterally pivoting or unfolding the two first arms 31, the counterweight base plate 52 is moved linearly and parallel to the longitudinal axis of the superstructure away from the axis of rotation 13 of the superstructure. The pivoting movement of the first arms 31 is compensated by the base bodies 72 of the connecting elements 30 pivoting laterally outwards (i.e., away from the longitudinal axis of the superstructure). In doing so, the base body 72 also pivots relative to the pivoting body 74 connected to the ballast cylinder 26. At a certain pivot angle of the first arms 31, the base bodies 72 are vertically aligned (see figure). Fig. 5 ).

[0091] By continuing to pivot the first arms 31, the distance between the counterweight base plate 52 and the upper carriage pivot axis 13 is further increased. In this process, the base bodies 72 of the connecting elements 70 pivot laterally outwards, so that they are inclined away from the longitudinal axis of the upper carriage. This position is in the Figure 6shown, wherein the first arms 31 here extend perpendicularly to the longitudinal axis of the upper carriage from the ballast frame 22, so that the ballast cylinders 26 have a maximum distance from the longitudinal axis of the upper carriage (this corresponds to a maximum swivel angle of the base bodies 72 outwards).

[0092] If the first arms 31 are pivoted further, the distance of the ballast cylinders 26 from the longitudinal axis of the upper carriage decreases again, so that the base bodies 72 pivot back inwards, possibly even beyond the vertical position, so that they are inclined inwards again in the end position of the counterweight base plate 52 (cf. Fig. 7 ).

[0093] It should be noted that the pivotable base bodies 72 of the connecting elements 70 have certain limit angles to the outside (see Fig. 6 ) and inwards (cf. Fig. 4 or 7) assume a position relative to the vertical, i.e., the basic bodies 72 pivot within a defined angular interval. This angular interval can be smaller than [-20° 20°], preferably smaller than [-15°, 15°], with respect to the vertical orientation (cf. Fig. 5 ). This means, firstly, that all counterweight plates stacked on the counterweight base plate 52 must be provided with a corresponding clearance or appropriately wide recesses through which the base bodies 72 can project without collision. Secondly, the pivoting movement of the base bodies 72 about the horizontal pivot axes 73 results in a height offset 80 of the counterweight base plate 52 (see figure). Fig. 5This height offset 80 is not very large, for example in the range of a few centimeters (e.g. 20 mm), but the mass to be lifted of the entire counterweight device 50 is very large in comparison. The resulting lifting work must be supplied by the adjusting cylinder 36 and taken into account in its design.

[0094] In a preferred embodiment, the pivotable base bodies 72 can be spring-loaded to press them into their home position. This position can, for example, be pivoted inwards, as in the Figure 4 shown, or a vertical position, as in Figure 5 The springs can be designed to be correspondingly strong, e.g., as disc springs. In the basic position, the swivel body 74 with the receptacle 76 is in a connection position, in particular for coupling with the coupling piece 27 of the ballast cylinder 26.

[0095] In the third embodiment, a key task of the ballast cylinders 26 can also be to press the counterweight device 50 against the ballast frame 22 (see above descriptions).

[0096] In addition, instead of a mechanical coupling of the two first arms 31 via a chain drive, two synchronously controlled adjusting cylinders 36 can be provided for the two first arms 31.

[0097] Finally, an alternative way to accommodate the relative movement between connecting element 70 and coupling piece 27 is shown in a fourth embodiment in the Figure 8The first arms 31 and the counterweight device 50 are shown schematically. As previously described, the piston rods of the ballast cylinders 26 are rotatably mounted in the cylinder shells with the coupling pieces 27 (at least in one adjustment mode). This rotational degree of freedom relieves the friction connection between the receptacle 76 and the coupling piece 27. In contrast to the third embodiment, the connecting elements 70 are formed in one piece, with a pivoting movement between the connecting element 70 and the coupling piece 27 being enabled by a convex connection. For this purpose, both the receptacle 76 and the coupling piece 27 preferably have correspondingly curved or rounded surfaces, resulting in a connection similar to a ball joint.

[0098] The solution according to the invention requires, compared to the prior art, only a single storage device for the counterweight assembly 50 in the undercarriage. The adjustment of the counterweight radius takes place during crane operation and not during the setup of the counterweight. The undercarriage can therefore be optimally designed without this feature. Reference symbol list:

[0099] 10 Mobile crane 13 Superstructure slewing axis 14 Superstructure 20 Ballasting device 22 Ballast frame 24 Winch 26 Ballasting cylinder 27 Coupling piece 31 First arm 32 Second arm 33 Vertical slewing axis 34 Vertical slewing axis 36 Hydraulic adjusting cylinder (or other linear actuator) 37 Nose 41 Non-rotating gear 42 Non-rotating gear 43 Connecting element (chain) 45 First gear 46 Second gear 47 Third gear 48 Fourth gear 49 Connecting element (chain) 50 Counterweight device 52 Counterweight base plate 60 Coupling wheel 70 Connecting element 72 Base body 73 Horizontal slewing axis 74 Swivel body 75 Horizontal slewing axis 76 Mount 80 Height offset

Claims

1. Mobile crane (10), comprising a drivable undercarriage, a superstructure (14) mounted on the undercarriage so as to be rotatable about a vertical superstructure axis of rotation (13), with a ballasting device (20), and a counterweight device (50) couplable with the ballasting device (20), which comprises a counterweight base plate (52) and at least one connecting element (70) extending from the counterweight base plate (52) for lifting and coupling the counterweight device (50) with the ballasting device (20), characterized in that the distance of the counterweight device (50) from the superstructure axis of rotation (13) in the ballasted state is adjustable via at least one first arm (31) of the ballasting device (20), which is pivotable about a vertical pivot axis (33), the first arm (31) in the ballasted state is connected to the counterweight base plate (52) via a pivotable coupling element, which is mounted so as to be pivotable relative to the first arm (31) and to the counterweight base plate (52) in such a way that the counterweight base plate (52) is adjustable in a linear movement radially with respect to the superstructure axis of rotation (13) by simultaneous pivoting of the first arm (31) and the coupling element.

2. Mobile crane (10) according to claim 1, wherein the counterweight device (50) comprises two mutually spaced-apart connecting elements (70) for coupling the counterweight device (50) with the ballasting device (20), wherein the ballasting device (20) comprises two pivotable first arms (31), which are synchronously pivotable for adjusting the distance of the counterweight device (20) from the superstructure axis of rotation (13).

3. Mobile crane (10) according to claim 2, wherein the first arms (31) are arranged laterally on the ballasting device (20), in particular on a ballast frame (22), and are pivotable in opposite directions of rotation for adjusting the distance of the counterweight device (50) from the superstructure axis of rotation (13).

4. Mobile crane (10) according to claim 2 or 3, wherein each of the first arms (31) is pivotable via its own hydraulic cylinder (36), and the hydraulic cylinders (36) are synchronously controllable.

5. Mobile crane (10) according to claim 2 or 3, wherein one of the first arms (31) is pivotable via a hydraulic cylinder (36), and the first arms (31) are mechanically coupled to one another via a gear transmission in such a way that, upon actuation of the hydraulic cylinder (36), they pivot synchronously, wherein the gear transmission preferably comprises gears (45, 46) connected rotationally fixedly to the first arms (31), which gears are coupled to one another via a connecting means (49), in particular a chain, as well as at least one interposed further gear (47, 48).

6. Mobile crane (10) according to any one of the preceding claims, wherein the ballasting device (20) is designed to lift the counterweight device (50) from a depositing region of the undercarriage and to deposit it thereon, wherein the at least one connecting element (70) has, at an end opposite the counterweight base plate (52), a coupling portion via which coupling with the ballasting device (20) can be established.

7. Mobile crane (10) according to claim 6, wherein the ballasting device (20) comprises at least one hydraulic ballasting cylinder (26), which can be brought releasably into engagement with the coupling portion of the at least one connecting element (30), wherein the coupling portion comprises a receptacle (76) into which a coupling piece (27) of the ballasting cylinder (26) can be moved, in particular by rotation of the superstructure (14) about the superstructure axis of rotation (13).

8. Mobile crane (10) according to claim 7, wherein the receptacle (76) and / or the coupling piece (27) has a rounded contour which enables an articulated movement of the coupling piece (27) within the receptacle (76) in the loaded state.

9. Mobile crane (10) according to claim 7 or 8, wherein the ballasting cylinder (26) comprises a cylinder barrel and a piston displaceable therein with a piston rod, at the free end of which the coupling piece (27) is located, wherein the piston is mounted in the cylinder barrel so as to be rotatable about the longitudinal axis of the piston rod, wherein the ballasting cylinder (26) is actuable by a hydraulic system, wherein the ballasting cylinder (26) and the hydraulic system are configured in such a way that, in the ballasted state, the piston rod is blocked in a locking mode against extension and rotation, while in an adjustment mode rotation of the piston rod relative to the cylinder barrel at the same extension position is possible, wherein the piston rod in the adjustment mode is preferably extended further than in the locking mode.

10. Mobile crane (10) according to any one of the preceding claims, further comprising at least one second counterweight element stackable on the counterweight base plate (52), which has at least one recess through which the at least one connecting element (70) protrudes in the deposited state.

11. Mobile crane (10) according to any one of the preceding claims, further comprising a measuring device for detecting a ballasting state of the mobile crane (10), which is transmitted to a control unit, in particular for load moment limitation, wherein the measuring device preferably comprises at least one sensor by means of which a current pivot angle of the at least one first arm (31) can be detected.

12. Mobile crane (10) according to any one of the preceding claims, wherein a second arm (32) is connected to the at least one first arm (31) so as to be pivotable about a vertical pivot axis (34), wherein the at least one connecting element (70) of the counterweight device (50) can be coupled with the at least one second arm (32), in particular via a ballasting cylinder (26) arranged on the second arm (32).

13. Mobile crane (10) according to claim 12, wherein the first and second arms (31, 32) are coupled to one another in such a way that, during a pivoting movement of the first arm (31) about its pivot axis (33), the second arm (32) is automatically pivoted about the pivot axis (34) connecting the two arms (31, 32) to one another, in particular in the opposite direction of rotation, wherein the pivot angles of the first and second arms (31, 32) are in a defined ratio to one another.

14. Mobile crane (10) according to claim 12 or 13, wherein the first and second arms (31, 32) are connected to one another via a second hydraulic cylinder, wherein the first hydraulic cylinder (36), which pivots the first arm (31) relative to the superstructure (14), and the second hydraulic cylinder, which pivots the second arm (32) relative to the first arm (31), are actuated in a synchronized manner such that the angular velocities of the first and second arms (31, 32) during pivoting are in a defined ratio to one another.

15. Mobile crane (10) according to claim 12 or 13, wherein the first and second arms (31, 32) are mechanically coupled to one another via a gear transmission in such a way that, upon actuation of the hydraulic cylinder (36) pivoting the first arm (31) relative to the superstructure (14), they pivot synchronously, wherein the gear transmission preferably comprises a first gear (41) connected rotationally fixedly to the superstructure (14) and a second gear (42) connected rotationally fixedly to the second arm (32), which are coupled to one another by a connecting means (43), in particular a chain.

16. Mobile crane (10) according to any one of claims 1 to 11, wherein the at least one connecting element (70) of the counterweight device (50) is pivotably connected to the counterweight base plate (52) and can be coupled with the at least one first arm (31), in particular via a ballasting cylinder (26) arranged on the first arm (31).

17. Mobile crane (10) according to claims 2 and 16, wherein the connecting elements (70) are each connected to the counterweight base plate (52) so as to be pivotable about a horizontal pivot axis (73) in such a way that, when the first arms (31) are pivoted for linear adjustment of the distance of the counterweight device (50) from the superstructure axis of rotation (13), the connecting elements (70) pivot laterally, in particular perpendicularly to the direction of movement of the counterweight device (50), in order to compensate for a circular movement of the first arms (31).

18. Mobile crane (10) according to claim 17, wherein the connecting elements (70) comprise a main body (72) pivotably connected to the counterweight base plate (52), at the end of which facing the first arm (31) a pivot body (74) is in each case fastened so as to be pivotable about an in particular horizontal pivot axis (75), in order to compensate for an inclined position of the connecting elements (70), wherein the pivot body (74) has a coupling portion via which coupling with the first arm (31) of the ballasting device can be established.

19. Mobile crane (10) according to claim 17 or 18, wherein the connecting elements (70) are each biased into a vertical or inwardly pivoted position by a restoring element, in particular a spring.

20. Mobile crane (10) according to one of claims 17 to 19, wherein the connecting elements (70) are connected to the counterweight base plate (52) so as to be pivotable relative to the vertical in both directions by a maximum pivot angle, wherein the maximum pivot angle is preferably less than 20°, particularly preferably less than 15°.