Method, system, and computer program product for moving a load with multiple cranes

Abstract

The present invention relates to a method for moving a load (20) using multiple cranes (10) with luffing jibs (14). According to the present invention, one of the cranes (10) is designated as a leading crane, and its movement is followed by the other trailing cranes. The crane control units (40) exchange data. When the load (20) is raised or lowered, the trailing crane's lifting mechanisms are adjusted so that the height (lifting height) of the load contact points on each lifting means (16) remains within a defined window near the leading crane's lifting height. During the luffing movement of the jib (14), the crane's luffing and lifting mechanisms are automatically controlled and / or adjusted so that the lifting height remains constant. The deviation of the lifting wire (18) from the vertical is measured for at least one crane, and if a deviation is detected, the luffing mechanism and / or slewing mechanism are controlled and / or adjusted to compensate for the deviation. Additionally, the present invention relates to a corresponding system and a corresponding computer program product.

Description

[Technical Field]

[0001] The invention relates to a method for moving a load by means of a plurality of cranes according to the preamble of claim 1, to a corresponding system according to the preamble of claim 12 and to a computer program product according to claim 15. [Background technology]

[0002] To ensure synchronized crane movements for the joint lifting of a load, conventional two- or multiple-crane lifts require continuous communication between the crane operators of the cranes involved in the lift and a designated signal person or supervisor. A particular feature of such multiple-crane lifts is that the movements of the other cranes are related to the safety of each crane. Thus, for example, an oblique lift (i.e., lifting wires that are out of vertical) can lead to overloading of one or more of the involved cranes, or an unsynchronized lift / lowering can lead to a shift in the center of gravity of the lifted load, which can also lead to overloading of one or more of the involved cranes. Similarly, cranes must be prevented from colliding with each other and with obstacles, as well as from moving into "prohibited" locations where they can no longer move independently.

[0003] For this reason, such multiple crane lifts are complex and safety-critical operations, requiring knowledge of a wide range of information to be known or calculated, such as the center of gravity of the load to be lifted, the mass of the load and sling, the proportional wire weights, their distribution to the individual cranes, the instantaneous diagonal pull, and the load factor relative to the maximum rated load of the cranes.

[0004] In such multiple crane lifts, dangers arise, in particular as a result of overloading the cranes due to angled pulls and shifting of the centre of gravity due to unsynchronised lifting / lowering of the load.

[0005] In particular, when cranes with different equipment are used for a multi-crane lift, it becomes difficult to synchronize the movements of the individual cranes. If cranes with luffing jibs (e.g., lattice boom cranes with main jibs or luffing jib tips, tower cranes with luffing jibs, etc.) are used for the lift and the cranes have different configurations (e.g., jibs of different lengths or jibs that can rotate around different axes), these cranes will perform different movements of the jib heads when luffing their jibs by the same angle. Thus, even if the length of the lifting wire is the same, the contact point of the load suspended by each crane will move along different paths or to different locations. To compensate for this effect, at least one of the cranes will have to hoist or lower the lifting wire in addition to the luffing movement to compensate for the difference in height of the contact point.

[0006] If crane rotation is required to move a co-hung load, one of the cranes must, in addition to rotating, also raise and lower the jib and adjust the lifting wire, while the other crane only performs the rotation movement so that the load is moved at the same height. The individual movements are so complex that it is almost impossible to avoid a diagonal pull.

[0007] If the center of gravity is high or low, unsynchronized lifting / lowering of the load will cause the center of gravity to shift, thus creating the risk of load changes and even overload on one or more cranes. In this case, the cranes involved in the lifting may become overloaded without moving their own lifting mechanisms. For example, if the center of gravity is low, the center of gravity will shift towards the stationary crane when another crane lowers a load. As a result, the load on the stationary crane will increase and it may become overloaded. Therefore, synchronizing the lifting / lowering of loads is an essential requirement for safe lifting by multiple cranes.

[0008] If it is not possible to accurately identify and correct for all relevant factors, the load factor relative to the rated load should be reduced or reduced accordingly for all involved cranes, in accordance with applicable regulations. This reduction could be 25% or more. Thus, the allowable load factor relative to the nominal rated load could be 75% or less. In contrast, if all the above-mentioned influences and risk factors can be accurately identified and monitored by equipment, the involved cranes could be operated up to their nominal rated load. Summary of the Invention

[0009] Against this background, the object of the present invention is to enable the lifting or movement of a typical load to be carried out more safely and efficiently by multiple cranes.

[0010] According to the present invention, this object is achieved by a method having the features of claim 1, a system having the features of claim 12 and a computer program product having the features of claim 15. Advantageous embodiments of the invention emerge from the dependent claims and the following description.

[0011] A method for moving a load by means of a plurality of cranes is therefore proposed. Each of the cranes using this method comprises a superstructure rotatable about a vertical axis of rotation by a slewing gear, a jib that can be raised and lowered about a horizontal axis by a hoisting mechanism, a lifting gear means that is vertically adjustable by a lifting mechanism and configured to lift the load, and a control unit that is capable of automatically controlling the superstructure, the jib, and the lifting gear means (or corresponding drives or actuators). The jib can be, for example, a jib mounted on the superstructure, in particular a lattice mast jib, a hoisting jib tip fixed to the main jib, or a luffing jib of a tower crane. Each of the crane's lifting mechanisms preferably comprises at least one winch, and in each case the winch is provided with at least one lifting wire guided above the jib tip so that it can be hoisted and lowered, and the lifting wire is fixed to the lifting gear means.

[0012] In the case of such cranes, the problem mentioned at the beginning exists, so that raising and lowering the jib not only causes horizontal movements of the load, but also vertical movements, so that synchronized movements to achieve a specified movement of the co-suspended load becomes particularly difficult precisely when different cranes (e.g., different crane types or even just different equipment) are used.

[0013] According to the invention, one of the cranes involved in the co-lifting is defined as the leading crane. The other crane is a trailing crane that follows the movements of the leading crane, in particular automatically. This is preferably achieved by the trailing crane's control unit automatically controlling and / or adjusting the actuators of the trailing crane involved in the movements (in particular the slewing gear, the hoisting mechanism, and the lifting mechanism) accordingly. To enable this process, the control units of the cranes involved in the lifting exchange data. For example, the trailing crane's control unit (or the crane operator) must know what movement the leading crane is currently performing (i.e., the current position of the leading crane at successive points in time) in order to be able to control and / or adjust the movements of the trailing crane itself accordingly.

[0014] According to the invention, when a load is raised or lowered, the lifting mechanism of the trailing crane is adjusted so that the height of the contact point of the load on each of the lifting means of the trailing crane (hereinafter referred to as the lifting height) is maintained within a defined range or window in the vicinity of the lifting height of the leading crane, where the window is understood to be the height portion between the lower and upper limits.

[0015] The adjustment to reset the lifting height can be made by the operator or crane operator. For this purpose, the operator or operator is provided with the information necessary for this (e.g., his current lifting height, the current lifting height of the leading crane, a defined window, window limits, and / or parameters representing the current deviation from the lifting height of the leading crane, associated with limits as needed). This information can be displayed on a display device of the crane and / or on a mobile display device associated with the trailing crane. In this case, the crane operator can be assisted to manually reset the lifting height so that the lifting height of the trailing crane can be maintained within the specified window in the vicinity of the lifting height of the leading crane.

[0016] Alternatively, adjustments to reset the lifting height can be made automatically by the trailing crane control units, which for this purpose adjust the lifting mechanism so that the contact point is maintained within a window defined by upper and lower limits.

[0017] The upper and lower limits of the defined window are in particular defined as distances from the current lifting height of the crane and may be the same or different. Any desired reference point may be used to adjust the lifting height, for example a contact point on the load itself, any point on the lifting means or a defined point on the lifting wire.

[0018] According to the present invention, the crane's hoisting and lifting mechanisms are automatically controlled and / or adjusted by their respective control units for horizontal load movement (i.e., the vector of this movement is the horizontal component) so that the lifting height remains constant during the jib hoisting movement. The load contact point is thus moved at a constant height when the jib is hoisted. This simplifies load adjustments when multiple cranes are used to move a load, since the load maintains a constant height while the cranes perform different jib movements. Maintaining a constant lifting height can be initiated by input from the crane operator or can be fully automatic by the control unit.

[0019] Of course, combined operations are also possible, in which the load is both lifted / lowered and moved horizontally. In the simplest case, for this purpose, a combination of the above-mentioned control for realizing a constant horizontal movement and control of the lifting mechanism for varying the lifting height is used.

[0020] According to the invention, the deviation from the vertical of the lifting wire holding the lifting gear means is measured for at least one crane involved in a multi-crane lift. In this case, both forward / backward (i.e., parallel to the undulating surface) and right / left (i.e., transverse or perpendicular to the undulating surface) deviations are measured and analyzed. If a deviation from the vertical is detected, a skew of the crane in question is present and must be compensated. For this purpose, the hoisting mechanism and / or slewing gear are controlled and / or adjusted by a control unit so that the deviation from the vertical is compensated. In this case, the lifting wire remains vertical, so that no skew occurs even when the load is moved, which often involves a complex combination of individual movements of the associated cranes. The compensation for the deviation from the vertical can be initiated by the crane operator's input or completely automatically by the control unit.

[0021] In the simplest case (multiple crane lift with only two cranes), monitoring and compensation for the diagonal pull can be performed on only one of the cranes involved in the lift. This is because the forces during the lift are always balanced, so that a diagonal pull on one crane also means a diagonal pull on at least one other, second crane. If a diagonal pull is compensated on one crane, this also eliminates the diagonal pull on the other cranes. However, it is of course possible to monitor the diagonal pull on several or all of the involved cranes. Compensation after a diagonal pull is detected can be performed sequentially: first, the diagonal pull on one particular crane is compensated. If, after this compensation, a diagonal pull still exists on one or more other involved cranes, the diagonal pull on the second crane, etc. is compensated.

[0022] Cranes performing co-hoisting are equipped with undercarriages and can be moved around a construction site. In this case, it may be difficult for all cranes to move in exactly the same direction and for the horizontal distance between the tips of the jibs, through which the lifting wires are guided, to remain constant relative to one another. Rather, unevenness in the ground or imprecise undercarriage control and rolling resistance can cause a crane to run away from or towards another crane. This can lead to a skew in the lifting wire of the moving crane. The skew caused by the runaway can be indicated by the control / regulation means according to the present invention and compensated for, preferably fully automatically, by corresponding compensating movements in the hoisting mechanism and / or the slewing gear.

[0023] All of the above-mentioned control and adjustment processes (lift height resetting, horizontal load movement, and diagonal pull compensation - all of which can be realized as separate support systems in the control unit and used simultaneously) can be performed fully automatically by the crane's control unit, ideally no longer relying on human adjustments. This makes it less prone to error and minimizes the potential risks of overload or operation in a dangerous area. Alternatively, for example, lift height resetting of a trailing crane can be performed manually (and with the assistance of) the trailing crane's crane operator, while diagonal pull compensation and maintaining the horizontal load path are performed automatically by the control unit.

[0024] Preferably, combined control of the load movement, such as combined rotation or raising and lowering of the crane by the operator, is always possible. The commonly used assistance system according to the present invention preferably continues to function, i.e., when the crane jib is manually raised or lowered, the length of the lifting wire is automatically adjusted so that the horizontal movement of the load continues, and / or the rotation angle of the crane is automatically adjusted so that no oblique pulling occurs.

[0025] The method according to the invention can be performed by a single operator, who specifies the load movement, for example via an input device on the leading crane or a mobile input device. The method can also be performed by one or more operators, who specify the load movement. Control of the leading crane and repositioning of the trailing crane are then initiated automatically by the control unit. Alternatively, each crane can be assigned an operator or crane driver, who can manually intervene in the automatic control of the crane.

[0026] It should be noted that the phrases "two crane lift" and "multiple crane lift" are used synonymously and refer to the lifting or moving of a general load by multiple (i.e., at least two) cranes.

[0027] The control unit may be the crane controller or part of the crane controller, or alternatively, the control unit may be configured as a separate computing device connected to the crane controller.

[0028] Preferably, the control units of all trailing cranes are configured to perform automatic skew compensation. In this case, rearrangement of the leading crane's horizontal movement (i.e., in the case of rotation of the superstructure and / or swivel of the leading crane's jib to move the load horizontally) can optionally be performed solely by automatic skew compensation. Since each trailing crane is driven by the control unit so that its respective lifting wire always remains vertical, this means that the trailing crane's horizontal movement is adjusted to the leading crane's movement so that the load contact point or jib tip spacing is always constant (otherwise skew would occur). However, this already achieves rearrangement of the trailing crane's horizontal movement. Resetting of the lifting height can be performed automatically or manually at the same time.

[0029] In a possible embodiment, at least three cranes are used to carry out the method, the cranes lifting or moving a common load. Thus, there are at least two trailing cranes that follow the movement of the leading crane. In this case, different windows for resetting the lifting height, i.e., different limits on the maximum deviation of the lifting height from the current lifting height of the leading crane, are specified for the at least two trailing cranes. This is particularly preferred if the trailing cranes are of different types or equipped differently. Alternatively, the same windows may be defined for the trailing cranes. The windows can be specified or adjusted by the operator or the signal person. As a result, the current situation on the construction site can be adapted.

[0030] In a further possible embodiment, after the load is attached, the lifting height of the trailing crane can be set to a fixed value relative to the lifting height of the leading crane (calibration). For example, the difference between the lifting height of the trailing crane and the lifting height of the leading crane can be set to zero, or the ratio of the lifting heights can be set to 1. Then, during the lifting, the difference or ratio of the lifting height of the trailing crane to the lifting height of the leading crane is continuously monitored and optionally corrected by the control unit of the trailing crane. After the load is attached and before the lifting height is calibrated, the lifting mechanism (i.e., the lifting wire) is preferably slightly preloaded. This can be realized automatically by the crane's control device.

[0031] In a further possible embodiment, the crane's lifting means is suspended on a lifting wire guided above the jib tip of the jib, and the movement of the trailing crane is automatically matched to the movement of the leading crane so that the lateral spacing of the jib tips remains constant. This prevents the occurrence of skewing. Alternatively, or in addition, the movement of the trailing crane can be automatically matched to the movement of the leading crane so that a specified orientation of the load remains constant while the crane is moving. In this case, the operator only needs to specify the direction in which the load will be moved. Alternatively, it is conceivable that the operator could, for example, keep the position of the center of the load constant while specifying a specific rotation of the load.

[0032] In further possible embodiments, if the lifting height of the trailing crane is outside a specified window or if the detected deviation of the lifting wire from vertical exceeds a specified threshold, a warning is issued and / or all crane movements are stopped. The warning can be in the form of an acoustic signal and / or a corresponding visual display (e.g., a display on the crane's display device and / or a mobile display device). Preferably, if the deviation in the lifting height or the orientation of the lifting wire is too large, crane movements are stopped so that the crane can be brought back into tolerance by the crane operator, in particular by manual control.

[0033] In a further possible embodiment, the movement of the load (i.e., specifically the target position and / or path) is specified and / or controlled via the input means. The leading crane is controlled based on the input of the input means, i.e., based on a control command input via the input means. The trailing crane is made to follow the leading crane manually or automatically via the control unit, so that the load performs the specified movement. The input means may be arranged on the crane, in particular on the leading crane. Alternatively, the input means may be configured as a mobile input unit such as a tablet. It is also conceivable that multiple input means are provided, i.e., one is provided on the leading crane and another is a mobile device.

[0034] In a further possible embodiment, each crane is equipped with a monitoring means for load torque limiting, which may be part of the respective control unit or may be implemented on a separate unit. Each crane is equipped with a corresponding detection device for detecting the load currently acting on it. The detected values ​​are transferred to the monitoring means, which compares these values ​​with corresponding threshold values ​​for the crane (threshold values ​​vary from crane to crane depending on the crane's type, configuration, or current orientation). If the detected current load on one of the cranes exceeds the maximum allowable load applicable for the current position, the load torque limiting device outputs a warning and / or stops the crane's movement. The crane then communicates the stop of movement to the other associated cranes, which then also perform the stopping process. Thus, when implementing the method according to the present invention, a conventional load torque limiting device can be used. It continuously monitors the maximum allowable load or allowable rated load of the crane and automatically intervenes if these values ​​are exceeded (or are about to be exceeded).

[0035] Additionally, predictive calculations can be made of the loads that will result if the crane continues to move, allowing for early intervention. Such predictive calculations can also be used to prevent a crane from being moved to a location where it cannot be moved without damaging another crane.

[0036] Furthermore, the cranes may be equipped with means for monitoring and preventing collisions with each other and with other obstacles (e.g. structures). For this purpose, the cranes may be equipped with corresponding sensors and / or cameras, which detect the situation around the crane.

[0037] In a possible embodiment, the control units of the cranes form a network and exchange data with each other. For this purpose, the cranes are preferably equipped with corresponding transmitting and receiving means connected to the control units. This allows wireless data exchange between the cranes and other devices integrated into the network. Alternatively, for example, when stationary cranes are used, a wired communication path may be integrated into the network. At least one mobile display device is integrated into the network and communicates with one or more cranes, i.e., the crane's control units. Preferably, a mobile display device is associated with only one crane. Data received from the crane can be displayed on the display device. The mobile work terminal can be configured, for example, as a tablet or a mobile operating station.

[0038] In addition, each crane preferably has its own crane display device, particularly in its cab. All relevant information about the actual crane, such as load rate, load, and / or diagonal pull information, can be displayed on the crane display device. The mobile display device thus forms a second display device on which specific data of the associated crane or all other cranes, particularly relevant to a multi-crane lift, can be displayed.

[0039] The mobile display device may simultaneously be or comprise an input means for specifying and / or controlling the movement of the suspended load.

[0040] In a further possible embodiment, the mobile display device may be operated in a reading mode, in which information relating to all cranes involved in a multiple crane lift is displayed on the display device. The display device of the leading module is operated in particular by a supervisor or signalman controlling and / or monitoring a multiple crane lift and therefore needs to be able to see data relating to all cranes involved. In the reading mode, one or more of the following exemplary items of information may be displayed in any combination:

[0041] Information regarding the crane's identification and / or current configuration. This may include the serial number or other identification information for each crane.

[0042] Information about the current lifting height of the trailing crane compared to the current lifting height of the leading crane. This relationship may be displayed as a difference and / or a ratio. Additionally, a visual display of the respective allowable windows may be provided.

[0043] Information about the deviation of the lifting wire from the vertical of at least one crane. The indication of the oblique pull can be visual and / or numerical.

[0044] Information about the wind speed detected at at least one crane. Preferably, the current wind speed is detected at each crane via a corresponding detection device (e.g. an anemometer).

[0045] For example, information about the activation of an emergency stop on a crane due to exceeding acceptable thresholds for load / lifting height / orientation of the lifting wire.

[0046] Information about the load currently acting on the crane.

[0047] Information about activated reductions of the maximum allowable load or allowable rated load of the crane. This reduction can be activated for one or more cranes if not all important parameters for monitoring the deviation of the diagonal pull or lifting height are available.

[0048] In a further possible embodiment, the mobile display device may be operated in an operator mode, in which only information relating to the associated crane (leading or trailing crane) is displayed on the display device. In the operator mode, the display device is operated in particular by the crane operator of the leading or trailing crane. In the operator mode, one or more of the following exemplary items of information can be displayed in any combination:

[0049] Information regarding the identity and / or current configuration state of the associated crane. This may include the crane's serial number or other identifying information.

[0050] Information about the current lifting height of the crane. If the crane is the leading crane, only the lifting height may be displayed. If the crane is a trailing crane, instead of or in addition to the current lifting height, the current lifting height compared to the current lifting height of the leading crane may be displayed, for example as a difference and / or ratio. Additionally, a visual indication of the tolerance window may be provided.

[0051] Information about the deviation of the lifting wire from the vertical. The indication of the oblique pull can be visual and / or numerical.

[0052] Information about wind speed detected by the crane.

[0053] For example, information about the activation of an emergency stop due to the exceeding of acceptable thresholds for load / lifting height / orientation of the lifting wire.

[0054] Information about the load currently acting on the crane.

[0055] Information about activated reductions in the maximum allowable load or allowable rated load of the crane.

[0056] The information described above may be displayed visually in the reading mode and / or the operator mode, and may optionally be supplemented by corresponding numerical information.

[0057] It may be realized that multiple display devices are incorporated into the network and that a crane whose associated mobile display device has been switched to leading mode is automatically defined as the leading crane (and vice versa; identifying a crane as the leading crane will automatically switch its associated display device to leading mode, while the display devices of the remaining cranes will automatically be operated in operator mode).

[0058] In a further possible embodiment, there are at least two mobile display devices present and connected to the network of cranes, one of the mobile display devices being associated with the leading crane and operated in leading mode while at least one other display device is associated with the trailing crane and operated in operator mode, preferably each trailing crane being associated with a display device that is operated in operator mode.

[0059] Preferably, there is only one leading crane at any one time, ie, there is only one mobile display device in leading mode in the network.

[0060] Preferably, a distinctive name or alias can be assigned to each crane for display on, for example, a mobile display device in reading mode, which is more intuitive than, for example, an abstract number sequence.

[0061] Preferably, in reading mode, all information about the cranes is spatially organized on the display device. Preferably, the spatial location of each crane can be moved as desired in the view on the display device.

[0062] Preferably, a separate corridor, i.e. a separate window, for deviation of lifting height from the leading crane may be defined for each trailing crane.

[0063] The present invention further relates to a corresponding system for moving a load using a plurality of cranes. The system is preferably configured to perform the method according to the present invention in any of the above-mentioned variants and comprises a plurality of cranes for performing the joint lifting of a load. Each of the plurality of cranes comprises, as already described above, a superstructure rotatable about a vertical axis of rotation by a slewing gear, a jib that can be raised and lowered about a horizontal axis by a hoisting mechanism, a lifting gear means vertically adjustable by a lifting mechanism and configured to hoist a load, and a control unit capable of automatically controlling the superstructure, the jib, and the lifting gear means. The control unit is preferably configured to perform the method according to the present invention (i.e., the above-mentioned steps related to and that can be performed on the control unit).

[0064] The system according to the invention is characterized in that one of the cranes is defined as a leading crane, and the control unit is configured to control the trailing crane so that its movements follow those of the leading crane, and the crane control units are configured to exchange data. The control unit is preferably configured to automatically control the trailing crane as appropriate. Manual control can also be performed, as described above with respect to the method according to the invention.

[0065] According to the invention, the control unit is configured to control and / or adjust the lifting mechanism of the trailing crane so that when the load is raised or lowered, the lifting height is maintained within a specified window around the lifting height of the leading crane. The adjustment for resetting the lifting height can be performed by an operator or crane driver. For this purpose, the operator or driver is provided with the necessary information (e.g., his / her current lifting height, the current lifting height of the leading crane, the defined window, the window limits, and / or parameters representing the current deviation from the lifting height of the leading crane (optionally regarding the limits)). This information can be displayed on a display device of the crane and / or a mobile display device associated with the trailing crane. In this case, the crane driver is assisted in manually resetting the lifting height so that the lifting height of the trailing crane can be maintained within the specified window around the lifting height of the leading crane.

[0066] Alternatively, the adjustment of the lifting height resetting may be performed automatically by the control unit of the trailing crane, which may be configured accordingly. To this end, the control unit of each trailing crane adjusts the lifting mechanism so that the contact point is maintained within a window defined by upper and lower limits.

[0067] According to the invention, the control unit is further configured to automatically control and / or adjust the hoisting and lifting mechanisms of the crane with respect to horizontal movements of the load in the direction of the jib so that the lifting height remains constant in the case of hoisting movements of the jib.

[0068] According to the invention, at least one of the cranes is provided with a measuring device for detecting a deviation from the vertical of the lifting wire supporting the lifting gear means, and the control unit of said crane is configured to control and / or adjust the hoisting mechanism and / or the slewing gear in case of a detected deviation so that the deviation is compensated for or no unacceptable deviation occurs.

[0069] With regard to the properties, advantages and possible embodiments of the system according to the invention or of the individual elements of the system, the above statements regarding the method according to the invention, i.e. the resulting advantages, properties and possible embodiments, apply analogously, and therefore will not be repeated. The system may comprise any of the elements, properties or embodiments described with respect to the method according to the invention, in any combination.

[0070] In a possible embodiment, the control units of the cranes are configured to form a network and exchange data with each other, and the system comprises at least one mobile display device integrated into the network and configured to receive and display data from at least one crane. The above statements regarding possible embodiments of the network or the mobile display device(s) apply equally to the system according to the invention.

[0071] In a further possible embodiment, the system comprises the input means described above and / or at least one monitoring means described above.

[0072] Furthermore, the invention relates to a corresponding computer program product for carrying out the method according to the invention, which computer program product comprises commands which, when executed, cause the control unit of the crane to carry out the steps of the method described above (in any embodiment) with respect to the control unit. Naturally, this does not apply to steps carried out by a human operator.

[0073] The computer program product may further include commands that are executed by one or more of the above-described mobile display devices and that, for example, implement the above-described reading mode and / or operator mode.

[0074] Preferably, the computer program product can be run on a conventional crane controller, eliminating the need for retrofitting of hardware components, in which case conventional load torque limits can be incorporated as described above. [Brief explanation of the drawings]

[0075] Further features, details and advantages of the invention will become apparent from the following description of embodiments with reference to the drawings. [Figure 1] FIG. 1 is a schematic diagram of an embodiment of a system according to the present invention having one leading crane and two trailing cranes. [Figure 2] FIG. 2 shows two cranes when performing a two-crane lift using the method according to the invention. [Figure 3] FIG. 3 shows an enlarged view of the tip of the jib of the crane of the system according to the invention, which includes a measuring device for determining the verticality of the lifting wire according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0076] FIG. 1 shows an embodiment of a system according to the invention, comprising three cranes 10 for carrying out the method according to the invention. The system comprises one leading crane and two trailing cranes. Each crane 10 is equipped with a control unit 40, which may be, for example, a crane controller. Each crane 10 further comprises its own display unit 42, for example a crane display in the crane's cab. The cranes 10 are communicatively connected to one another via transceiver means 44, which in the embodiment shown are connected to the control unit 40 via a coupling device 46 (for example, a "managed switch" or NAT (network address translation)) and allow data to be exchanged wirelessly. The cranes 10 can thus form a network. In this case, preferably, each crane 10 is connected to all the other cranes 10 (or their control units 40).

[0077] Furthermore, each crane 10 is associated with a mobile display device 60 which is ideally wirelessly connected to only one crane 10 at any one time. The mobile display device 60 may be a tablet or any other mobile device (e.g., laptop, smartphone, mobile control device, etc.) The mobile display device 60 forms a secondary display on which certain information is displayed (more on this below).

[0078] In the embodiment described herein, all cranes 10 in the system involved in the multiple crane lift are mobile cranes with a mobile undercarriage 11 (which may have, for example, a crawler chassis, but the crane 10 can also be without a crawler chassis) and a superstructure 12 mounted on the undercarriage 11 so as to be rotatable about a vertical axis. In this case, a mobile crane is generally understood to be a mobile crane, including a lattice-mast crane. An embodiment of the crane 10 involved in the multiple crane lift according to the present invention is shown in FIG. 2, where an example of tandem lifting is used, with one leading crane (the crane 10 on the left) and one trailing crane (the crane 10 on the right). The crane 10 has a jib 14 that can be raised and lowered about a horizontal axis, with a lifting wire 18 guided above the jib tip 15, the cable being attached to a lifting wire winch, which is preferably located on the superstructure 12, so that the cable can be hoisted and unhoisted. In either case, the lifting gear means 16 is secured to a lifting wire 18 to which a load 20 to be lifted may be secured. The load 20 may include a crossbar that may be connected to the lifting gear means 16 of the crane 10.

[0079] 2, each jib 14 comprises a main jib pivotally hinged on the superstructure 12 and a jib tip pivotally connected to the main jib and supported and swung via guying means. However, the exact configuration of the crane 10 is not relevant to the method according to the invention. Similarly, other types of cranes or even fixed cranes (with hoisting tips) can be used for multiple crane lifts.

[0080] In the case of the crane 10, the superstructure 12 can be rotated by a slewing gear, the jib can be raised and lowered by a luffing mechanism (e.g., hydraulic luffing cylinders and / or guy cable winches), and the lifting wires 18 can be adjusted vertically by a lifting mechanism (e.g., a drive for the lifting wire winch). In the case of the crane 10 shown in Figure 2, for example, the luffing mechanism comprises deflection rollers mounted on guy supports pivotally connected to the superstructure 12, adjustable guy wires, and further adjustable guy wires between the guy supports arranged on the jib for raising and lowering the luffing tip relative to the main jib.

[0081] Preferably, there is a crane lifting manager (signal man / operator / supervisor) who coordinates the lifting by the multiple cranes, and a crane operator is assigned to each crane 10. Alternatively, the lifting can be carried out automatically without the intervention of a crane operator, so that only a signal man needs to be present. A further possibility is that one of the crane operators (especially the crane operator of the crane 10 defined as the leading crane) may also be the signal man.

[0082] Lifting with multiple cranes requires constant communication between the individual crane operators and the signal person to ensure synchronized operation of the involved cranes 10 and to avoid hazards. Furthermore, the center of gravity of the load 20 to be lifted must be known or calculated, as well as the size of the load 20, the size of the lifting means 16, and the proportional weight of the wire and its distribution to the individual cranes 10. The skewing of the lifting wire 18 and the utilization rate of the cranes or the current load relative to their respective capacity loads must also be monitored during the lifting process. In the case of lifting with multiple cranes, there is a risk, for example, of overloading the cranes 10 due to skewing, or of shifting the center of gravity due to unsynchronized lifting / lowering of the load.

[0083] If it is not possible to accurately detect and correct all relevant high-impact and risk factors, for example, ISO 12480-1:1997, "Cranes - Safe use - Part 1: General," section 11.4.4, requires that an appropriate load utilization reduction (also called TLT (Traglasttable, load capacity table) utilization reduction or limitation) be implemented for all involved cranes. Such reduction may be 25% or more. Thus, the nominal allowable utilization of the load may be 75% or less. In contrast, if all the aforementioned contributing factors and risk factors can be accurately determined and monitored by equipment, the cranes 10 may be used up to their rated loads.

[0084] The method according to the invention allows the safe operation of the cranes 10 in a multi-crane lift, taking into account all relevant influencing and risk factors, so that the nominal loads of the cranes 10 involved can be optimally utilized. Furthermore, the safety of multi-crane lifts is increased, since the cranes 10 are intelligently controlled and synchronized, eliminating the need for complex modifications and retrofitting of existing cranes for this purpose. This is made possible by the simultaneous application of multiple assistance systems to the individual cranes 10 and the realization of a network for communication and synchronization of the cranes 10 involved.

[0085] Based on a preferred embodiment, possible assistance systems are described below, which are used simultaneously on each of the cranes 10 involved in a multi-crane lift. These assistance systems are implemented by the respective control units 40.

[0086] 1. "Horizontal Load Path" (HLP) support system When activated by the operator, the load 20 is automatically moved horizontally, i.e., to a constant height, when the jib 14 of the crane 10 is luffed (wippened). This simplifies load adjustment for multiple cranes 10 (as well as for individual cranes 10). The load 20 maintains a constant height despite the activation of the luffing mechanism.

[0087] As a result, in the case of jib hoisting, two separate movements (e.g., hoisting downwards, increasing the horizontal spacing of the load 20 from the superstructure 12 while simultaneously lowering the height of the load 20) become a single movement (changing the horizontal spacing of the load 20 from the superstructure 12). In the case of rotation (a further change in the rotation angle of the superstructure), three separate movements become two movements (the rotation angle and the horizontal spacing of the load 20 from the superstructure 12).

[0088] 2. Vertical Line Finder (VLF) support system In the case of a lift with multiple cranes, if the spacing of the jib tips 15 is not the same as the spacing of the contact points of the load 20 on the lifting means 16, then a cross pull will occur on the lifting wires 18 within the cranes 10, creating additional stresses that may possibly cause damage and lead to overloading of the crane structure. In this case, the forces caused by the cross pull are always in equilibrium. If there is a cross pull on one crane 10, there will also be a cross pull on at least a second crane 10.

[0089] In the VLF diagonal pull monitoring system, forward / backward and lateral pulls on the lifting wire 18 are displayed and optionally corrected, so that the operator or crane driver can recognize and prevent horizontal and forward pulls. In one or more cranes 10 of the system, forward / backward and lateral pulls on the lifting wire 18 are measured by a sensor system 50. Preferably, the crane driver is informed on the crane display 42 whether the lifting wire 18 is in a vertical position (e.g., in the form of a plan view of the jib tip 15 and the load 20).

[0090] When a skew is present, the crane 10 may be configured to automatically correct the skew by compensating for movements in the hoist mechanism and swing gear when actuated by the crane operator (e.g., by an input button on a master switch). Alternatively, the correction can be performed automatically (i.e., without operator intervention) by the control unit 40. Preferably, superimposed rotation or hoisting by the crane operator is possible at any time. When the crane operator operates the swing gear, a correction is performed by the hoist mechanism, and when the hoist mechanism is activated, a correction is performed via the swing gear so that a skew does not occur.

[0091] Preferably, the monitoring and correction of skew also occurs when the crane 10 is moved by the undercarriage of the substructure 11. That is, the crane 10 corrects skew either through operation by the crane operator or fully automatically by compensating for the movement of the slewing gear and hoisting mechanism. In a multi-crane lift, when the cranes 10 move using their undercarriage, it is often difficult to ensure that all cranes 10 move in exactly the same direction. Because the operation of the undercarriage is usually imprecise, skew can occur when the cranes 10 separate due to rolling resistance. The VLF assistance system displays the skew caused by the drive and corrects the skew accordingly.

[0092] Due to the force balance described, compensating for the skew on one of the cranes 10 will automatically compensate on the other cranes 10 as well. Therefore, the VLF assistance system must be active on at least one of the cranes 10. Preferably, the VLF assistance system is activated on each crane 10, and in a further embodiment, the control units coordinate with each other so that on a crane 10 the skew is corrected by compensating for movements in the luffing mechanism and slewing gear. This may be done simultaneously on several cranes 10 working together, but correction on a single crane 10 is easier to perform and is usually sufficient.

[0093] 3 shows an embodiment of a sensor system 50 for detecting the oblique pulling of the lifting wire 18. The jib tip 15 of the undulating tip 14 is shown equipped with a deflection roller, through which the lifting wire 18 with the lifting gear means 16 (here the lower hook block) is guided. One of the reevings of the lifting wire 18 is connected to a measuring device 50 fixed to the jib tip 15, which detects deviations of the lifting wire 18 from the vertical to the sides (i.e. left / right) and in a direction parallel to the undulating surface (i.e. forward / backward) and forwards this to the control unit 40. Of course, alternative detection devices are also conceivable.

[0094] 3. "Load Leveling" Support System Synchronized lifting / lowering of a jointly lifted load 20 is a prerequisite for safe multi-crane lifting. The involved cranes 10 must maintain their associated hook heights or lifting heights (defined here as the height of the contact points of the load 20 on the lifting gear means 16 of the cranes 10) in order to keep the load 20 balanced. In the method according to the invention, one of the involved cranes 10 is called the leading crane ("leader"), and the remaining cranes 10 (trailing cranes or "followers") are directed towards it.

[0095] The control units 40 of the cranes 10 use their sensor systems to measure their lifting heights 30 or 32 and exchange this information wirelessly with each other via the transmitting / receiving means 44, so that the lifting height 30 of the trailing crane is maintained, either manually or automatically, within a predetermined window 34 (the "load level window") around the contact point or lifting height 32 of the leading crane. Fully automated lifting height resetting is preferred here, as it significantly simplifies the process. This process is illustrated in FIG. 2 according to an embodiment, with the left-hand crane 10 being the leading crane. The lifting height itself is indicated by the dash-dotted line 32. For the trailing crane (the crane 10 on the right), a window 34 is defined, characterized by the maximum upper clearance (upper dashed line 33) from the leading crane's lifting height 32 and the maximum lower clearance (lower dashed line 31) from the leading crane's lifting height 32. As shown in Figure 2, the upper and lower spacings of the window 34 from the leading crane's lifting height 32 may be set the same or differently for each trailing crane. The trailing cranes' contact points or their lifting heights (characterized by dashed lines 30) must remain within the selected window 34. The lifting mechanisms of the trailing cranes are adjusted manually or automatically by the control unit 40 so that this adjustment is reliably achieved.

[0096] In the case of multiple trailing cranes, this applies to each individual trailing crane. The trailing crane windows 34 may be the same or differently specified or identifiable for each crane (e.g., corresponding to the allowable center of gravity displacement for lifting and the load variations associated with each crane).

[0097] A synchronized lifting process using the method of the present invention with a "load leveling" assistance system can be performed as follows: After the load is contacted, each trailing crane sets its hook height (i.e., lifting height differential Δ-height) relative to the leading crane to zero. During the ascent (and also descent) of the load 20, each trailing crane must maintain the differential Δ-height within a fixed window 34 around zero. If a trailing crane does not maintain the specified limits 31, 33, a visual or audible warning is sent to the mobile display device 60 and / or all cranes 10, and / or all movement is stopped (i.e., automatic intervention by the control unit 40 in the crane controller). The lifting height 32 of one or more trailing cranes can then be corrected manually or, preferably, automatically by the control unit 40. After the height correction is made, the crane movement is released and can continue.

[0098] A suitable limit for TLT utilization in multiple crane lifts is preferably 10%, under the following assumptions: For Crane 10 VLF support system for detecting and displaying skew HLP support system to reduce movement complexity - Wire length measurement to achieve load leveling The network between the cranes involved (multiple crane lifting networks, i.e. "connectivity") Display unit for displaying relevant parameters For display units (crane display 42 and / or mobile display device 60 - see Figure 1) Visualization of all crane parameters related to lifting, especially load leveling It should be noted that, according to ISO 12480-1, when using the above assistance systems, there is no need to reduce the TLT utilization, since all relevant factors are accurately detected and corrected. However, a corresponding reduction in the TLT utilization may nevertheless be desirable for safety reasons.

[0099] Each individual crane 10 (leading and trailing crane) preferably additionally has a load torque limitation (LTL) to monitor and optionally intervene promptly if its maximum permissible load is exceeded during a multiple crane lift. In particular, the above-mentioned limitation of the TTL utilization does not take the form of a load reduction at the LTL, but rather merely serves as a notice / warning to the crane operator that the planned nominal load (planned nominal load under the jib head in a multiple crane lift) must not be higher than a certain value at this radius (e.g., 90% of the permissible load). The lifting manager or signal person can specify further limitations, particularly for each crane 10 involved, which preferably do not convey any information (diagonal lift, lift, etc.). In cases where there are no detection or correction possibilities for a crane 10, a reduction of at least 25% should be applied in accordance with ISO 12480-1.

[0100] Additionally, as will be explained below with reference to the embodiments, the crane operator can preferably activate a limit on TLT utilization along with a proactive reduction in TLT (with corresponding reduction in stops and advance warnings).

[0101] "Reduction of allowable load utilization" allows the switch-off (stopping movement) and advance warning of the load utilization (display on the screen or crane display 42) to be manually reduced individually in specific steps (e.g. 1% steps) by the user. This reduction is maintained even if the crane controller is switched off and then on again.

[0102] The maximum permissible load indicates the limit of the respective crane 10, whereby the associated switch-off is preferably implemented as a safety function (overload protection LTL), which cannot be influenced or changed by the operator. This safety function also remains particularly effective if a reduction in the permissible load utilization is selected.

[0103] In a preferred embodiment, the operator may, at his discretion, reduce the allowable load utilization for operation. This operational reduction is below the limit of the crane 10 and therefore represents an operational constraint, not a limit of the crane 10 limit.

[0104] For example, the overload protection (LTL) can realize the following limiting values: LTL switch-off limit of 100% and LTL pre-warning limit of 90%. Of course, other limiting values ​​and / or pre-warning stages are conceivable. The "reduced load utilization" in particular uses the same functions as the LTL (also with regard to the deadlock / setup button).

[0105] The reduction in the allowable load utilization can preferably be set by the operator. The adjustment range may be between 20%-100%. The pre-warning reduction can preferably be set separately by the operator. The adjustment range may be between 18%-90%, and the interval between switch-off and pre-warning can be at least 1 / 10 of the selected switch-off value.

[0106] It should be emphasized here that all ratios and values ​​mentioned are by way of example only and may differ from the values ​​mentioned for all cranes 10 or for a particular crane 10 of a system according to the invention.

[0107] With reference to the embodiment shown in FIG. 1, in the following the network of cranes 10 of the system according to the invention will again be described, which is concerned with a lifting by multiple cranes.

[0108] Wireless connectivity / communication between the cranes 10 and the signallers involved in the lift is required for the crane operator and the crane lift manager or signaller to communicate digitally and / or interact with each other without wiring the cranes 10 together. Information retrieved from the cranes 10 for a safe multi-crane lift is displayed either on the crane display 42 or on a secondary display on a mobile display device 60 (e.g., tablet), which may be connected to a network, for example, via either an Ethernet or Wi-Fi access point. The signaller may have their own display or use the crane display 42 of the leading crane.

[0109] Thus, the cranes 10 are communicatively connected to one another via wireless connections. For WLAN-based communication, a Phoenix Contact proprietary mesh grid is preferably used to restrict communication to the cranes 10 in the system. Although each mobile device can see the network, third-party devices cannot log into the mesh grid. Since the local machine network is preferably substantially identical on all cranes 10 (except perhaps for a few add-ons), NAT (Network Address Translation) technology is preferably used.

[0110] The mobile display device 60 may be incorporated into a network, for example via Ethernet or wireless LAN, and may communicate with an associated crane 10. If wireless LAN is used, the mobile display device 60 is not considered a mesh node, but rather an individual device connected to exactly one access point (i.e., to exactly one crane 10).

[0111] Information retrieved from other cranes 10 should ideally be displayed on the mobile display device 60 (secondary display) and not on the actual crane display 42. For this purpose, preferably software runs on the latter device which retrieves the required information from the current crane 10 and from other cranes 10 in the same network. The crane display 42 must show all relevant information about the actual crane 10 (e.g. utilisation, load and / or diagonal pull information).

[0112] Two methods, MCOM or RTP (real-time transport protocol) web services, among others, can be used to communicate with Master-5. To keep the load on the control unit 40 low, the number of devices communicating with one control unit 40 must be reduced to a minimum. Too many devices requesting information from the control unit 40 can disrupt operation.

[0113] Preferably, the mobile display device 60 can be operated in two modes: a reading mode (display for a signal person or supervisor) and an operator mode (display for the crane operator(s)). It is preferable to be able to select between these visual representations.

[0114] Preferably, there is only one mobile display device 60 in leading mode (=leading device) in the entire network. All other devices are operated in operator mode. The first mobile display device 60, declared as the leading device, switches to leading mode. The associated crane 10 is preferably automatically determined as the leading crane. The other cranes 10 become trailing cranes.

[0115] Reading Mode: One or more of the following items of information for each crane 10 involved in a multiple crane lift are shown on a common display or indication: a) Serial number (identification information) b) TLT usage rate c) Setting the allowable TLT utilization rate d) Difference in lifting height from the leading crane, including the allowable passage (window 34) e) Diagonal pull in a direction parallel to the side (left / right) and the undulating surface (forward / backward) f) Activating a motion stop (e.g. after exceeding the maximum permissible load of the crane 10) g) Activating an emergency stop f) Maximum wind speed for all cranes involved10 Preferably, the maximum values ​​of b), c) and d) are visually highlighted to allow for a faster or better overview. All information of the cranes 10 is preferably summarized based on location information in the reading mode, and the spatial location of each crane 10 on the illustrated mobile display device 60 (reading device) can be moved as desired. Preferably, each serial number can be supplemented with an alias.

[0116] Operator Mode: At least one of the following items of information about the associated crane 10 is displayed: a) The difference in lift from the leading crane, including the specific window 34 of the crane 10 itself. b) Activating an emergency stop on the crane 10 c) TLT utilization rate for crane 10 itself d) Setting the allowable TLT utilization reduction (switching off) for the crane 10 itself e) Diagonal pull on the crane 10 itself, in a direction parallel to the side (left / right) and the undulating surface (forward / backward) f) Wind speed for the crane 10 itself [Explanation of symbols]

[0117] 10 Crane 11 Undercarriage 12 Superstructure 14 Jib 15 Jib tip 16 Lifting means 18 Lifting wire 20 Suspended load 30 Trailing crane lifting height 31 Lower limit of the window for head 32 Leading crane lifting height 33 Upper limit of window for head 34 Window for head 40 Control Unit 44 Transmission and Reception Means 46 Coupling device 50 Lifting wire measuring device 60 Mobile Display Devices

Claims

1. A method for moving a load (20) using a plurality of cranes (10), each of the plurality of cranes (10) comprising: an upper structure (12) rotatable by a swivel gear about a vertical axis of rotation; a jib (14) that can be raised and lowered by a luffing mechanism about a horizontal axis; a lifting means (16) vertically adjustable by a lifting mechanism and configured to suspend the load (20); a control unit (40) capable of automatically controlling the superstructure (12), the jib (14), and the lifting means (16); Each of them has One of the cranes (10) is defined as a leading crane; The movement of the leading crane is followed by the trailing crane, which is the remaining crane among the plurality of cranes (10), The control units (40) of the plurality of cranes (10) exchange data for tracking movements; The lifting mechanism of the trailing crane is particularly controlled by the control unit (40) so that when the load (20) is raised or lowered, a lifting height (30), which is the height of the contact point of the load (20) on the lifting gear means (16) of the trailing crane, is maintained within a predetermined window (34) in the vicinity of the lifting height (32) of the leading crane; the hoisting mechanism and the lifting mechanism of the plurality of cranes (10) are automatically controlled and / or coordinated with respect to horizontal movement of the load (20) so that the lifting height remains constant during the hoisting movement of the jib (14); a deviation of the lifting wire (18) from the vertical is measured for at least one of the cranes (10), and if the deviation exists, the hoisting mechanism and / or the slewing gear are controlled and / or adjusted by the control unit (40) so as to compensate for the deviation; method.

2. At least three cranes (10), different windows (34) for the lifting height (30) are defined and / or can be defined for at least two of the trailing cranes; The method of claim 1.

3. After the load (20) is attached, the lifting height (30) of the trailing crane relative to the lifting height (32) of the leading crane is set to a fixed value; Preferably, in this case, the lifting mechanisms of all the cranes (10) are preloaded.

3. The method according to claim 1 or 2.

4. The lifting means (16) of the crane (10) is suspended on the lifting wire (18) guided above the jib tip (15) of the jib (14); the movements of the trailing crane are automatically matched to the movements of the leading crane so that the horizontal spacing of the jib tips (15) remains constant and / or the defined orientation of the load (20) remains constant; The method according to any one of claims 1 to 3.

5. If the lifting height (30) of the trailing crane is outside its defined window (34) or if the detected deviation of the lifting wire (18) from the vertical exceeds a defined threshold, a warning is issued and / or all crane (10) movements are stopped. The method according to any one of claims 1 to 4.

6. The movement of the load (20) is defined and / or controlled via input means; the leading crane is controlled based on control commands input via the input means, and the trailing crane automatically follows the leading crane, particularly via the control unit (40), so that the load (20) performs a defined movement; The input means are preferably formed in the crane (10), in particular in the leading crane, or are configured as a mobile input unit. The method according to any one of claims 1 to 5.

7. each said crane (10) is provided with a monitoring means for load torque limiting; The monitoring means receives the load currently acting on each crane (10) and detected by the detection device, and compares this load with a maximum allowable load; If the load currently acting on one of the cranes (10) exceeds the maximum allowable load, a warning is issued and / or the movement of all the cranes (10) is stopped. The method according to any one of claims 1 to 6.

8. The control units (40) of the cranes (10) form a network and exchange data with each other; at least one mobile display device (60) integrated into said network for receiving and displaying data from said at least one crane (10); The mobile display device (60) is preferably associated with only one crane (10); The method according to any one of claims 1 to 7.

9. In the reading mode, information about all said cranes (10) is read, in particular: the identification and / or current setting status of the crane (10); the current lifting height (30) of the trailing crane compared to the current lifting height (32) of the leading crane; the deviation of the lifting wire (18) of the at least one crane (10) from the vertical; a wind speed detected at said at least one crane (10); Initiating an emergency stop for the crane (10); The load currently acting on the crane (10), and activating a reduction in the maximum allowable load of the crane (10); one or more of the items of information relating to the mobile display device (60) are displayed on the mobile display device (60). The method according to any one of claims 1 to 8.

10. In operator mode, information about the associated crane (10) is displayed, in particular: the identification and / or current setting of the crane (10); the current lifting height (30) of the trailing crane compared to the current lifting height (32) of the leading crane; the deviation of the lifting wire (18) from the vertical; the wind speed detected by the crane (10); Activating emergency stops, The load currently acting on the crane (10), and activating a reduction in the maximum allowable load of the crane (10); one or more of the items of information relating to the mobile display device (60) are displayed on the mobile display device (60).

10. The method according to claim 8 or 9.

11. There are at least two mobile display devices (60), one of the mobile display devices (60) is associated with the leading crane and is operated in the leading mode; the at least one other mobile display device (60) is associated with the trailing crane and is operated in the operator mode; Preferably, each said trailing crane is associated with a said mobile display device (60) which is operated in said operator mode.

11. The method according to claim 9 or 10.

12. A system for moving a load (20) using a plurality of cranes (10), the system comprising at least two cranes (12), each of the plurality of cranes (10): an upper structure (12) rotatable by a swivel gear about a vertical axis of rotation; a jib (14) that can be raised and lowered around a horizontal axis by a raising and lowering mechanism; a lifting means (16) vertically adjustable by a lifting mechanism and configured to suspend the load (20); a control unit (40) capable of automatically controlling the superstructure (12), the jib (14), and the lifting means (16); Each of them has The control unit (40) of the crane (10) is particularly configured to carry out the method according to any one of claims 1 to 11, One of the cranes (10) is defined as a leading crane; the control unit (40) is configured to automatically control a trailing crane that is not defined as the leading crane, so that the movement of the trailing crane follows the movement of the leading crane; The control unit (40) of the crane (10) is configured to exchange data; the control unit (40) is configured to control and / or adjust the lifting mechanism of the trailing crane so that, when the load (20) is raised or lowered, a lifting height (30), which is the height of the contact point of the load (20) on the lifting gear means (16) of the trailing crane, is maintained within a predetermined window (34) in the vicinity of a lifting height (32) of the leading crane; the control unit (40) is configured to automatically control and / or adjust the hoisting mechanisms and the lifting mechanisms of the plurality of cranes (10) with respect to horizontal movement of the load (20) so that the lifting height (30, 32) remains constant during the hoisting movement of the jib (14); At least one of the plurality of cranes (10) is provided with a measuring device (50) for detecting deviation of a lifting wire (18) supporting the lifting gear means (16) from the vertical; the control units (40) of the plurality of cranes (10) are configured to control and / or adjust the hoisting mechanism and / or the slewing gear if a deviation is detected so as to compensate for the deviation. system.

13. The control units (40) of the cranes (10) are configured to form a network and exchange data with each other; the system comprising the at least one mobile display device (60) integrated into the network and configured to receive and display data from the at least one crane (10); The at least one mobile display device (60) is preferably further configured to perform the method according to any one of claims 9-11. A system according to any one of claims 1 to 12.

14. Further comprising at least one input means according to claim 6 and / or at least one monitoring means according to claim 7.

14. A system according to claim 12 or 13.

15. 13. A computer program product comprising commands which, when executed, cause the control unit (40) of the crane (10) to carry out the steps of the method of any one of claims 1 to 12 relating to the control unit (40).

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