Crane and method for monitoring the operation of such a crane

Abstract

The present invention relates to a method for monitoring the operation of a crane (1), wherein the overall center of gravity of the crane, which may be additionally loaded, is determined, and the position of the overall center of gravity relative to the tipping edge (20) of the crane is monitored, wherein the possible shift of the overall center of gravity caused by possible changes in different operating and / or influencing variables and the resulting future overall center of gravity position (x) is determined, the operating and / or influencing variables at least including different crane movements, wherein the overall center of gravity that is most critical relative to the tipping edge is determined from the plurality of determined future overall center of gravity positions, and possible crane movement limits are determined based on the position of the most critical future overall center of gravity relative to the tipping edge.

Description

Technical Field

[0001] The present invention relates to a method for monitoring the operation of a crane, in which the overall center of gravity of the crane, which may be additionally loaded with a load, is determined and its position relative to the tipping edge (Kippkante) of the crane is monitored. The present invention also relates to a crane, in particular a slewing tower crane, having drive means for crane movement and / or load movement and a crane controller for controlling the drive means, wherein the crane controller includes monitoring means for monitoring the crane load and limiting the crane movement when a critical crane load is reached. Background Art

[0002] In the case of cranes such as construction cranes (e.g., mobile and / or telescopic construction cranes or slewing tower cranes), it is generally monitored by a crane controller or a monitoring device built therein whether the stability of the crane is ensured or whether the load of the crane has reached a critical load limit value such that the crane is in danger of falling down or otherwise being threatened, so that subsequently, optionally, the corresponding drive means of the crane can be shut down in a timely manner, or only crane movements that allow the crane load to be reduced or at least not increased any further are permitted. In particular, for example, the lifting load and the outreach of the lifting load can be monitored by determining the tensile force acting on the sling or the torque generated thereby on the sling winch, and in terms of the outreach (Ausladung), by the position of the trolley or the length of the unwound trolley rope. Depending on the type of crane, the dimensions can also be determined in different ways. For example, in the case of a crane having a luffing jib, the outreach can be determined by the luffing angle and, optionally, the corresponding length of the telescopically extendable jib.

[0003] By determining the lifting load and its outreach, the load torque acting on the crane can be determined, which can be compared with a corresponding load limit in the form of a limit torque to ensure the stability of the crane. If the monitoring device detects that an unusually heavy load is being lifted, or a certain lifting load has moved too far outwards, the crane controller can, for example, shut down the lifting drive and the trolley drive to ensure the stability of the crane.

[0004] However, the stability of the crane depends not only on the aforementioned lifting load and outreach, but is also affected by other operating and influencing variables (e.g., movement speed and acceleration). For this purpose, for example, document DE 10 2005 035 729 A1 proposes continuously reducing the speed of the crane drive when the crane approaches its load limit due to a corresponding crane movement.

[0005] In addition, the stability of a crane depends not only decisively on the load moment carried by the crane, but also on the support base on which the crane is placed or erected. Usually, the crane is supported on the ground by extendable bottom supports, so there is usually a support quadrilateral defined by the connecting lines through the contact points. This support quadrilateral makes the stability direction-dependent because, at different rotational positions of the crane about its vertical crane rotation axis, the load moment is cancelled by balance moments of different magnitudes, which are generated by the different lever arms of the support forces on the supports. The supports define the tipping edge, and the distance between the hinge point of the rotatable upper part of the crane and this tipping edge is different depending on the direction of rotation of the upper part of the crane.

[0006] Furthermore, variable adjustable support bases have recently been used in order to be able to adapt the support system to limited space conditions. For example, if the crane is in a very narrow space condition at the roadside or on a sidewalk, it is sometimes not possible to fully extend the supports to span the largest support quadrilateral. In order to still be able to use the crane in the above installation situation, one or more only partially extended cable supports can be used to operate the crane, which of course affects the stability and must be taken into account by the monitoring device of the crane. Due to the incomplete or varying degrees of extension of the supports of the bottom support, a support surface deviating from a square or rectangle may be produced, in which the tipping edge defined by the contact points or by the connecting straight lines through the contact points can no longer extend rectilinearly or parallel to each other. Since the crane can absorb a smaller load moment when the load or the boom rotates on only partially extended supports, while the crane can transmit a larger load moment when the boom with the load rotates on fully extended supports, the above-mentioned direction-dependence of the stability is increased again.

[0007] In order to be able to ensure the safety of the crane in the case of such a variably constructed bottom support, document DE 10 2008021 627 A1 proposes to determine the tipping edge of the crane according to the actual position reached by the supports, and to determine the overall center of gravity of the crane system (i.e., the crane with the load suspended accordingly). Then, the correspondingly determined overall center of gravity is checked by the monitoring device to determine whether it is located within the support surface spanned by the tipping edge. The current position of the overall center of gravity relative to the support surface defined by the tipping edge is displayed on a display in the crane driver's cab, so that if the overall center of gravity approaches the tipping edge, the crane operator can stop the crane movement in a timely manner.

[0008] However, in the case of such monitoring of the overall center of gravity and its position relative to the tipping edge, it is not easy to achieve the following objectives: on the one hand, to achieve efficient crane operation, in which the crane operator can move the payload from the starting point to the destination using the available travel speed, and on the other hand, to timely shut down or slow down the crane movement in order to safely avoid critical crane loads. For example, if a large distance is required to be maintained between the correspondingly detected overall center of gravity and the tipping edge as a safety buffer, the mobility or load capacity of the crane will be severely restricted. Conversely, if only a smaller safety distance is required to be maintained between the overall center of gravity and the corresponding tipping edge, the corresponding crane movement may not be able to stop quickly enough. Summary of the Invention

[0009] Starting from this, the object of the present invention is to provide an improved crane and an improved method for monitoring the operation of a crane, which avoid the disadvantages of the prior art and further develop the prior art in an advantageous manner. In particular, it should be ensured that critical crane movements are timely restricted without unnecessarily restricting the effective operation of a crane with high handling capacity.

[0010] Therefore, not only the correspondingly detected overall center of gravity and its distance from the corresponding tipping edge are monitored, but also the possible offsets of the overall center of gravity under various operating and influencing variables are pre-estimated, and the remaining load and stability margins are estimated based on the future overall center of gravity position considered relative to the tipping edge, so as to be able to take necessary restrictions or countermeasures on the crane movement. According to the present invention, the possible offsets of the overall center of gravity caused by the possible changes of various operating and / or influencing variables (including different crane movements) and the resulting future overall center of gravity positions are determined, and then the most critical future overall center of gravity relative to the tipping edge is selected from the future overall center of gravity positions. Then, according to the position of the most critical future overall center of gravity relative to the tipping edge, possible crane movement restrictions are determined. By means of this pre-determination of the future overall center of gravity position, considering various operating and / or influencing variables and their changes, necessary countermeasures can be taken in a timely manner without unnecessarily restricting the crane operation and the performance of the crane.

[0011] In particular, based on the distance from the most critical future overall center of gravity selected to the nearest tipping edge, the outreach margin can be determined, i.e., the distance by which the outreach can still be increased without endangering the stability of the crane. In the case of a slewing tower crane, the outreach margin can be the distance by which the trolley on the jib can still move outwards. However, considering that the allowed outreach is direction-dependent due to the usually non-circular support surface of the crane's bottom support, a movement margin can also be determined for the possible slewing movement of the crane based on the distance from the most critical future overall center of gravity to the tipping edge. For example, if the crane slews to the right around its vertical crane slewing axis towards the less extended outrigger, the slewing angle to the right can be limited based on the said distance as the movement margin.

[0012] The most critical future overall center of gravity can be determined from among a plurality of possible future overall center of gravity positions, for example, based on the distance between the possible future overall center of gravity and the tipping edge of the crane's support base. If all the determined possible future overall centers of gravity are located within the support surface spanned by the tipping edge of the support base, the overall center of gravity closest to the tipping edge can be selected as the most critical overall center of gravity. However, if one or more possible future overall centers of gravity are located outside the support base, the overall center of gravity located outside or the overall center of gravity farthest from the tipping edge can be selected.

[0013] Based on the distance from the selected most critical overall center of gravity to the nearest tipping edge, the remaining load or stability margin can be determined, wherein for the case where the future overall center of gravity is located outside the support base, a negative load margin will be obtained, which may, for example, cause the monitoring device to shut down the crane.

[0014] Advantageously, the device for determining the future overall center of gravity not only takes into account various possible crane movements and the resulting inertial forces (e.g., inertial forces caused by the possible slewing movement of the crane, possible hoisting, and / or possible trolley movement), but also other influencing variables.

[0015] In particular, the possible offset of the overall center of gravity caused by wind loads can be determined. For example, the following wind force can be used for this purpose, which is obtained based on the maximum allowable wind speed at which the crane can operate or is obtained from the difference between the current wind speed and the maximum allowable wind speed.

[0016] Advantageously here, different wind directions and the resulting different offsets of the overall center of gravity can be determined and taken into account, wherein advantageously, only one or more wind directions having an adverse effect on the stability of the crane need to be considered. For example, in order to determine the possible offset of the overall center of gravity, the wind blowing from the rear and / or the wind blowing from the side at the maximum allowable wind speed can be considered.

[0017] In an improved example of the present invention, in order to determine a possible shift of the overall center of gravity, it is also possible to determine a structural deformation of the crane, which can be caused by current operations and / or influencing variables and / or changes in these operations and / or influencing variables. In particular, for example, the deformation of the crane and the resulting shift of the overall center of gravity can be calculated, which is caused, for example, by a given wind load when the wind blows from the front or from the side at a certain wind speed. Alternatively or additionally, the deformation of the crane can also be calculated, which can be caused by inertial forces resulting from load lifting and / or trolley movement and / or rotation of the crane about its vertical crane rotation axis and / or downward or upward swinging of the boom.

[0018] For example, if the outreach of the load suspended on the lifting hook of a slewing tower crane is increased by moving the trolley, the overall center of gravity shifts outwards not only due to the travel path of the trolley, but also due to the resulting bending deformation of the tower. For example, when the tower is deformed forward by a gust of wind from the rear, the overall center of gravity can shift in a similar manner.

[0019] In addition, for the shift of the overall center of gravity, centrifugal forces can be determined and taken into account. On the one hand, if the crane rotates about its vertical crane rotation axis, this centrifugal force can pull the load on the lifting hook outwards according to the lowering depth of the lifting hook. On the other hand, if in addition to the load the corresponding centrifugal moment also acts on the crane, additional deformations may also occur in the tower or the telescopic jib.

[0020] As an alternative or addition to the above influencing variables, for example, certain fault states and their influence on the shift of the overall center of gravity can also be considered. In particular, the rope breakage and its influence on the shift of the overall center of gravity can be considered. This consideration of the rope breakage may mean: on the one hand, the lack of the hook load in the whole system and its share in the overall center of gravity, and on the other hand, due to the reset of the pre-existing deformation under the load, the sudden breakage of the hook load will cause a dynamic load to act on the crane, especially in the form of a load applied towards the rear side of the crane.

[0021] Regarding the possible displacements to be determined and the resulting future overall center of gravity, all possible crane movements will advantageously be considered, where consideration can be made in each of the two directions of all the movement axes. In the case of a slewing tower crane, in particular, the outward and inward movement of the trolley, the lifting and lowering of the lifting hook, and the right and left rotation of the boom about the vertical crane rotation axis can be considered.

[0022] To determine the inertial forces caused by the travel of such a transporter, the lifting and lowering of the hoisting hook, and the rotation of the jib or other crane movements, the maximum movement speed and / or acceleration predefined by the crane controller can be used as a basis. If the monitoring device has not imposed any restrictions on the travel speed, the maximum travel speed and acceleration can be used as a basis. If, for example, the travel speed or an individual travel speed has been restricted due to approaching the permitted load limit, the inertial forces can be determined based on the restricted speed and / or acceleration, and from this, the possible shift of the overall center of gravity can be calculated.

[0023] In principle, the restrictions carried out by the monitoring device based on the most critical possible future overall center of gravity position relative to the tipping edge can be of different types. For example, all crane drives can be restricted, for example, by setting a reduced maximum speed and / or by setting individual drives of the crane drive (where only one of the multiple crane drives can be operated simultaneously).

[0024] In particular, the monitoring device can also selectively select or implement the restrictions to be carried out, in particular, based on the crane movements that form the basis of the shift and the resulting overall center of gravity, which overall center of gravity is subsequently selected as the most critical overall center of gravity. If the most critical overall center of gravity is caused, for example, by a counterclockwise rotation movement of the crane (for example, because this will result in a only partially extended support), the monitoring device can, for example, lock the slewing mechanism in the corresponding rotation direction while the hoisting hook can still be raised and lowered without restriction. In addition to the said selective restrictions, further crane movements that increase the tipping moment can be prevented, restricted, or limited, such as a further outward movement of the transporter of a slewing tower crane.

[0025] In an advantageous refinement of the invention, the tipping edge of the crane is determined based on the respective extended state of the support of the bottom support, so that different support configurations can be taken into account. For example, sensors can detect the current extended state of the respective support, so that subsequently, based on the detected extension value, the support base plane or the tipping edge can be determined, which support base plane or tipping edge can be determined based on the connecting line through the contact points.

[0026] Advantageously, the position and / or orientation of the tipping edge can also be obtained from a data memory in which the tipping edge and its position and orientation are stored for different extended states.

[0027] The monitoring device of the crane controller can calculate the possible offset and possible future position of the overall center of gravity and their positions relative to the tipping edge respectively based on the respective actual states, especially based on the respective current sensor values of the relevant parameters. Here, the monitoring device takes the current overall center of gravity as the starting point and determines the possible offset of the current overall center of gravity and the resulting possible future overall center of gravity according to the possible operations and influencing variables and their possible changes (for example, the drive of the crane drive, the wind force or possible deformations), so as to subsequently limit the crane movement in the above-mentioned manner.

[0028] However, alternatively or additionally, the determination of the theoretically possible future center of gravity position can also be carried out outside the crane controller and the monitoring device, especially pre-based on a model that takes into account various possible configuration states of the crane and considers the relevant operations and / or influencing variables and their possible changes. The parameter set pre-calculated using the model can be provided to the control device or the monitoring device of the crane, for example, through a data memory storing the respective parameter sets. Then, the monitoring device only needs to access the parameter set and call the relevant parameter set respectively according to the current overall center of gravity and / or the current positions of the slewing mechanism, trolley, lifting hook and / or boom, and the parameter set contains the future center of gravity position and is applicable to the corresponding current crane position and configuration. Brief Description of the Drawings

[0029] The present invention will be described in more detail below based on preferred exemplary embodiments and the relevant drawings.

[0030] Figure 1 A schematic side view of a mobile slewing tower crane is shown, the tower of which is supported on a rotatable superstructure and carries a boom with a trolley, and its chassis is supported on the ground by extendable supports.

[0031] Figure 2 Shows Figure 1 A top view of the crane, which shows the tipping edge defined by the extended supports of the bottom support, the current center of gravity position and the possible future center of gravity position, and the possible movement of the payload caused by the possible future center of gravity position and the resulting stability margin.

[0032] Figure 3 A graph showing the allowable outreach or outreach limit values obtained for different lifting loads and different boom positions when the supports of the bottom support are fully extended.

[0033] Figure 4 Shows similar to Figure 3 A graph of the outreach limit values for different lifting loads in the case where the supports of the bottom support are not fully extended. Detailed implementation mode

[0034] As shown Figure 1 in FIG. 1, the crane 1 can be configured as a mobile construction crane or a mobile slewing tower crane, which includes a tower 2 supported on a slewing platform 3, the slewing platform 3 is located on a chassis 4, and can be driven by a slewing mechanism drive 9 to rotate around a vertical slewing axis. The chassis 4 can be configured as a truck or can be moved in other ways, but optionally can also be a firmly anchored or supported support base.

[0035] The tower 2 can carry a boom 5, which can be pivoted up and down around a horizontal, laterally extending pivot axis (see Figure 1 FIG. 2). The pivoting drive device 12 for the boom 5 can, for example, pivot the boom 5 by means of a cable device.

[0036] The trolley 6 can be mounted on the boom 5 in a longitudinally movable manner, and the trolley drive device 11 can move the trolley 6, for example, via a corresponding trolley rope. The sling 8 can run on the trolley 6 in order to lift the load in a known manner, and a load lifting device (for example, in the form of a lifting hook 7) can be tied to the sling. For this purpose, the hoisting mechanism drive device 10 can drive the sling drum accordingly.

[0037] Optionally and thus only briefly described, the crane can include other drive devices, such as a telescopic boom with a telescopic drive device 13, a ballast adjustment drive device 15 for adjusting the ballast, or a travel drive device 14 for moving the entire crane (this is usually not the case in the shown embodiment of a mobile construction crane, since it is jacked up to lift the load).

[0038] The various drives are controlled by a central crane controller 16, which can provide the crane operator with a corresponding joystick or other input member in a known manner, so that the operator can control the different movement axes of the crane. The crane controller 16 includes a monitoring device 17, which monitors the crane load acting on the crane (especially the lifting load carried by the lifting hook 7) and the extension of the lifting hook 7 relative to the upright base of the crane through appropriate sensors. The extension can be determined, for example, by the position of the trolley 6 on the boom 5 and optionally according to the pivot angle of the boom 5 relative to the horizontal plane.

[0039] The position and operating state of the drive device and / or the crane elements movable thereby can be monitored by corresponding sensors, such that the crane controller 16 or the monitoring device 17 knows the respective current crane positions, i.e., in particular knows the rotation angle about the vertical crane rotation axis 18 and thus the orientation of the jib 5, the position of the trolley 6 (distance from the tower 2), the lowering depth of the load hook 7 and optionally the elevation angle of the jib 5 as well as the position of the ballast. Additionally, the load borne by the load hook 7 can be determined, for example, by a lifting load sensor for measuring the load of the hoisting mechanism.

[0040] Based on these current state variables of the crane 1, the monitoring device 17 can determine the current overall center of gravity of the entire system consisting of the crane 1 and the lifting load attached to the load hook 7, in particular determine the position of the current overall center of gravity relative to the contact area defined by the bottom support 19 as Figure 2 shown.

[0041] In Figure 2 , the current position of the overall center of gravity is denoted by the letter y, which can be known or determined by the monitoring device 17 from the aforementioned state variables and can be calculated or read out, for example, from a parameter set determined for the crane construction.

[0042] Furthermore, the monitoring device 17 can determine the tipping edge 20, which is the connecting line passing through the contact points of the bottom support 19. As Figure 2 shown, the bottom support 19 can, for example, include four supports, which can extend in pairs towards opposite sides of the chassis 4 and can be lowered to the ground in their respective extended positions. As Figure 2 shown, the supports of the bottom support 19 can be extended to different degrees, so that different geometric shapes of the support surface defined by the tipping edge 20 can be produced. Here, in principle, the supports can be extended arbitrarily (e.g., steplessly or stepwise), so that any number of differently configured contact surfaces or support surfaces can be produced. However, in practice, it makes sense that the supports may only allow some limited extended states, for example, each support can be extended by 1 / 4, 2 / 4, 3 / 4, and 4 / 4 or, for example, 1 / 3, 2 / 3, and 3 / 3. The resulting tipping edge 20 and its orientation can be calculated by the monitoring device based on the sensor signals or can also be read out for the allowed and / or detected extended states (in the form of values stored in the parameter set).

[0043] Based on the current overall center of gravity (denoted by y in Figure 2 ), the monitoring device 17 can determine the offset of the overall center of gravity and accordingly determine the possible future position of the overall center of gravity (denoted by x in Figure 2 ), where the possible offset can be determined for different operating and / or influencing variables and / or their changes.

[0044] In particular, with regard to a possible shift of the current overall center of gravity to a possible future overall center of gravity, different crane movements can be considered, i.e., for example, the rotation of the crane about the vertical crane rotation axis 18, the lifting or lowering of the load on the lifting hook 7, the movement of the trolley 6, the upward or downward swinging of the jib 5, the possible telescoping inwards and outwards of the jib 5 and / or the movement of the ballast.

[0045] In addition to the possible crane movements and the resulting inertial forces, external influencing variables on the crane can also be considered when determining the possible shift of the center of gravity position. In particular, the wind force or wind load on the crane 1 can be considered.

[0046] For example, when the wind pushes the tower from the rear, this wind load can actually be considered in the form of an additional inertial force on the lifting hook. Alternatively or additionally, this wind force can also be considered in the form of an actual shift of the overall center of gravity, in particular since the wind deflects the lifting load borne by the lifting hook, where the lowering depth of the lifting hook 7 can be considered if necessary, because the wind can deflect the load more when the lifting hook is lowered deeper than when the lifting hook moves closer to the trolley. However, alternatively or additionally, as described above, the deformation of the crane can also be considered, in particular the bending of the tower 2 caused by the wind load. For example, if the wind force pushes the tower 2 from the rear, the tower will deform slightly forward towards the jib, thereby increasing the outreach of the lifting hook 7 and accordingly moving the overall center of gravity of the system.

[0047] In order to determine the possible future overall center of gravity x, the deformation of the crane 1 can also be specifically considered, which can occur not only in the manner described due to the wind load, but also due to other load variables, in particular the lifting load received by the lifting hook 7 and the inertial forces generated by the rotation of the crane 1, the movement of the trolley 6, the raising and lowering of the lifting hook 7 or other of the aforementioned crane movements.

[0048] Since the crane structure and its deformation characteristics under load are known, the deformation of the crane can be calculated or determined based on the aforementioned inertial forces, wind forces and other loads acting on the crane. For example, this deformation of the crane structure can be determined based on a model, where the deformations occurring for different load magnitudes can be saved as a parameter set and provided to the crane controller 16 or the monitoring device 17 in an accessible manner. Alternatively, the deformation can also be calculated directly based on the influencing variables.

[0049] It can be said that starting from the current overall center of gravity and its position, the monitoring device 17 takes into account all possible operating variables and influencing variables and their possible changes (in particular possible crane movements, possible wind loads, and possible crane deformations), and thereby determines various possible offsets and the resulting possible future center of gravity positions (represented by the reference variable x in Figure 2 ).

[0050] The monitoring device 17 analyzes the relative position of the possible future center of gravity position x with respect to the tipping edge 20 and selects a position closest to one of the tipping edges 20 as the most critical future overall center of gravity. In Figure 2 , in addition to the letter x, this critical future overall center of gravity is also represented by the parameter x k .

[0051] Based on the distance of the critical future overall center of gravity x k from the nearest tipping edge 20, the monitoring device 17 can determine the remaining load or stability margin, and then determine from said load or stability margin how much the outreach of the crane can still be increased, for example, in the case of moving the trolley 6 outwards or swinging the boom 5 downwards or extending the boom 5 outwards.

[0052] The increase in mobility or outreach that can be given while still ensuring stability, determined in the manner described above based on the critical future overall center of gravity, is represented in Figure 2 by an arrow connecting the two trolley positions A and B.

[0053] Taking into account the tipping edge 20 and the corresponding outreach and position that may change due to the extension of the support, the monitoring device 17 can determine the possible new positions of the payload (Nutzlast) for all boom positions or rotational positions of the crane 1 for each lifting load attached to the lifting hook 7. In Figure 2 , these possible new positions of the payload for all boom positions are represented by the reference numeral 21, and a (roughly speaking, approximate) quadrilateral is obtained, the main axis of which is generally oriented as the main axis of the contact area of the bottom support 19 determined by the extended state of the support.

[0054] As Figure 2 shown, for a specific lifting load carried on the lifting hook 7, this outreach limit 21 is direction-dependent and changes for different boom positions or according to the rotation angle of the boom 5 about the vertical crane rotation axis 18.

[0055] As Figure 3As shown, for different payloads or different lifting loads attached to the lifting hook 7, the outreach limits 21 that become increasingly larger or smaller respectively can be determined accordingly. According to this outreach limit, the crane 1 or its monitoring device 17 knows how far the load attached to the lifting hook 7 can still be moved through the corresponding crane movements. Since the outreach limit 21 does not form a circle around the crane rotation axis 18, but has a (approximately and roughly speaking) rectangular or quadrilateral contour, the outreach limit 21 can be achieved not only by moving the trolley 6 outwards or swinging the boom 5 downwards, but also by the rotation of the crane 1 around its vertical crane rotation axis 18.

[0056] Accordingly, the monitoring device 17 can selectively switch off and / or slow down and / or limit the crane movements that cause reaching or getting closer to the outreach limit 21, that is, in particular, moving the trolley 6 outwards and the corresponding rotational movement around the crane rotation axis 18.

[0057] Compare Figure 3 and Figure 4 It can be seen that different extended states of the support of the bottom support 19 result in different-shaped outreach limits 21.

[0058] Therefore, the method for monitoring crane operation and the corresponding crane with a suitably designed monitoring device related thereto particularly have the following advantages:

[0059] - The calculation method here allows knowledge of all possible center-of-gravity positions of the entire system, which may be caused by external influences (such as wind), inertial forces, certain fault states (such as rope breakage), or other influences.

[0060] - According to the current crane construction and load position, all system states with relevant center-of-gravity positions that may occur during operation are considered.

[0061] - In this method, the deformation of the crane system is considered when determining the center-of-gravity position.

[0062] - Here, among all the investigated states, those states that lead to the lowest safety level related to system tipping or exceed the loads of individual components are used.

[0063] - The basic calculation method is designed to meet the calculation rules and calculation standards specified for each existing crane construction and current crane use.

[0064] - This method pre - provides the possible center - of - gravity positions of the system for all possible system states. Thereby, the allowable load positions and the related tipping degrees can be determined at any time for all possible movement directions of the upper part of the crane and the load, and they are used to control the crane movement.

[0065] - When determining the allowable load size and load position, additional restrictions stored in the controller are also used. Thus, system states with other restrictions of the participating components can be considered.

[0066] - The support pressure can be stored in the controller and used for additional monitoring / redundancy.

Claims

1. A method for monitoring the operation of a crane (1), in which method the overall center of gravity of the crane (1) that may carry a load is determined, and the position of the overall center of gravity relative to the tipping edge (20) of the crane (1) is monitored, characterized in that, the possible offsets of the overall center of gravity caused by possible changes in different operating and / or influencing variables and the resulting future overall center of gravity positions are determined, the different operating and / or influencing variables at least including different crane movements, wherein the most critical future overall center of gravity relative to the tipping edge (20) is determined from the determined plurality of future overall center of gravity positions, and possible crane movement limitations are determined based on the position of the most critical future overall center of gravity relative to the tipping edge (20).

2. The method according to claim 1, wherein, the most critical future overall center of gravity is selected according to its distance from the tipping edge (20), wherein a load margin and / or a stability margin are determined based on the distance between the selected most critical future overall center of gravity and the tipping edge (20), and crane movements that increase the tipping moment and / or reduce stability are selectively restricted or released according to the load margin and / or the stability margin.

3. The method according to claim 1 or 2, wherein, the possible crane movement limitations include cutting off and / or restricting crane movements, reducing the maximum speed or maximum acceleration of crane movements and / or restricting the crane drive to a single drive while stopping other crane drives.

4. The method according to claim 1 or 2, wherein, the possible offset of the overall center of gravity and the associated possible future overall center of gravity position are determined by the wind load that occurs.

5. The method according to claim 1 or 2, wherein, the possible offset of the overall center of gravity is determined based on the wind load from at least one determined wind direction.

6. The method according to claim 1 or 2, wherein, the possible offset of the overall center of gravity caused by the deformation of the crane (1) and the associated possible future overall center of gravity position are determined.

7. The method according to claim 1 or 2, wherein, the possible offset of the overall center of gravity and the associated possible future overall center of gravity position are determined by the influence of the inertial force from the crane movement.

8. The method according to claim 1 or 2, wherein, the possible offset of the overall center of gravity and the associated possible future overall center of gravity position are determined considering the centrifugal force acting on the crane (1) and / or the lifting load attached to the crane.

9. The method according to claim 1 or 2, wherein, the tipping edge (20) and its position and orientation relative to the vertical crane rotation axis (18) are determined according to the extension distance of the support of the bottom support (19).

10. The method according to claim 1 or 2, wherein, The outreach limit (21) is determined for the respective lifting load attached to the lifting hook (7) and / or for any lifting load attached to the lifting hook (7), respectively, as a function of the tipping edge (20) and its position and as a function of the determined possible displacement of the overall center of gravity, the outreach limit having different values for different rotational positions of the crane (1).

11. The method according to claim 10, wherein, the non-circular outreach limit (21) for the respective lifting load attached to the lifting hook (7) limits both the outward movement of the trolley (6) and / or the downward swing of the boom (5) and the rotation of the crane about the vertical crane rotation axis (18).

12. The method according to claim 4, wherein, the wind load is the maximum allowable wind load.

13. The method according to claim 5, wherein, the possible displacement of the overall center of gravity is determined on the basis of the wind load from the wind direction from the rear and / or from the side.

14. The method according to claim 7, wherein, the possible displacement of the overall center of gravity and the associated possible future overall center of gravity position are determined by the influence of inertial forces from rotation, lifting and / or trolley travel.

15. A crane having drive means (9, 10, 11, 12, 13, 14, 15) for crane movement and / or load movement and a crane controller (16) for controlling the drive means, wherein, the crane controller (16) has monitoring means (17) for monitoring the crane load and for limiting crane movement when a critical crane load is reached, wherein the monitoring means (17) is configured to monitor the position of the overall center of gravity of the crane, which may be loaded, relative to the tipping edge (20) of the crane (1), characterized in that the monitoring means (17) is configured to determine the possible displacement of the overall center of gravity caused by possible changes in different operating and / or influencing variables and the resulting future overall center of gravity positions, and to determine the most critical future overall center of gravity relative to the tipping edge (20) from the determined plurality of future overall center of gravity positions, and to determine possible crane movement limitations on the basis of the position of the most critical future overall center of gravity relative to the tipping edge (20), the different operating and / or influencing variables including at least different crane movements.

16. The crane according to claim 15, wherein, the crane is a rotating tower crane.

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