Method and device for operating a crane, and operating system for a crane

Abstract

The invention relates to an operating system for operating a slewing jib crane (1), comprising: - a crane control unit (15) which is positionally fixed in the slewing jib crane (1) and is designed to control one or more drives (8, 9, 10) of the slewing jib crane (1) in accordance with control commands in order to move a load (7) or a load hook; - a plurality of mobile operating units (20, 20a, 20b), each of which comprise: • at least one movement operating element (22) which is designed to generate a control command by manual operation, • a communication unit (21) which is designed to set up a communication connection (K) to the crane control unit (15) and a direct or indirect communication connection to one or more further ones of the operating units (20, 20a, 20b), • a control unit (23) which is designed • to set up an active communication connection between the crane control unit (15) and one of the operating units (20, 20a, 20b) by means of the communication unit (21) and to transmit control commands in dependence on the operation of the at least one movement operating element (22), and • to communicate a signal, in dependence on an operation of the at least one activation operating element (25), that particular adoption of the active communication connection to the crane control unit (15) is desired.

Description

[0001] Description

[0002] Method and device for operating a crane and operating system for a crane

[0003] Technical field

[0004] The invention relates to a crane, in particular a method for operating a crane with a mobile control unit. The invention further relates to a method for transporting a suspended load from a starting position to a target position, particularly when there is no direct line of sight between the starting position and the target position.

[0005] Technical background

[0006] Cranes typically have a boom from which a lifting cable extends, and a hook is attached to the cable to hold a load to be lifted. The load can be raised or lowered via the lifting cable. Additionally, by rotating and / or tilting the boom and / or moving a trolley along the boom, the lifting hook and / or the suspended load can be moved in a horizontal plane to allow the load to be moved within a working area.

[0007] In a tower crane, for example, the jib is mounted on a stationary tower so that it can rotate. A trolley travels along the jib. The lifting cable runs along the trolley. By rotating the jib around the tower and moving the trolley along the jib, the load can be transported and positioned within the working area.

[0008] Typically, the load movement in a tower crane is controlled by a crane operator in a cabin. The cabin is positioned high on the tower, giving the operator a complete view of the crane's working area. The cabin rotates with the boom, ensuring the operator always has a clear view of the suspended load. From the cabin, the operator can use a joystick to control the boom's rotation and the trolley's movement, as well as the raising and lowering of the load cable, allowing them to reach any position within the working area.

[0009] Another way to control the crane is for the operator to control the load's movement from outside the cabin using a mobile control unit. This can be done, for example, with a joystick or a similar control device. This allows the operator to control the load's movement more precisely, as they can be closer to its current position.

[0010] Mobile control units for controlling the movement of a load within a construction site's work area are known. The crane operator moves to the position of the load to be transported and controls or guides the crane hook to a desired starting or load-handling position. There, the load is attached, and by appropriately operating the control unit, the crane operator moves the load to the desired target position by lifting, moving, and lowering it.

[0011] However, construction sites can sometimes be very difficult to access, preventing a crane operator from moving directly from a starting position to a destination. Furthermore, the starting and destination positions may be located at different points on the site, and the distance between them may not be traversable by the crane operator within a reasonable timeframe, or the transport route may not be readily visible. For example, a starting position and a destination position might be located on opposite sides of a building under construction, over which the load must be transported. In these cases, it is not always possible for the crane operator to maintain a constant view of the load and safely guide it from the starting position to the destination.For example, German patent application DE 10 2013 006 258 A1 discloses how to automate the movement of the load hook to a specific target position within the crane's working area. The crane operator can specify a target position and initiate an automated movement to that position, whereby the crane's drive devices no longer need to be manually operated or controlled by the crane operator, but are controlled automatically by the crane control system. This is achieved using a mobile, portable target signal transmitter that can be variably positioned within the crane's working area, as well as position determination devices for automatically determining the current position of the target signal transmitter relative to the load hook and / or a crane element, and target control devices for automatically controlling the drive devices based on a signal from the position determination devices, such that the load hook is automatically moved to the mobile target signal transmitter.The automatic approach of the mobile target signal transmitter with the load hook can be fully automatic, so that the crane performs corresponding crane movements when the portable signal transmitter is moved, thus following the crane operator walking across the construction site with the target signal transmitter.

[0012] The object of the present invention is to provide an improved method for transporting a load by guiding a crane operator, in which, in particular, a safe and monitored movement trajectory of the suspended load can be ensured and the load can also be transported to hard-to-see places in the crane working area.

[0013] Disclosure of the invention

[0014] This problem is solved by the method for operating a crane with at least two mobile control units according to claim 1 and by an operating system, a mobile control unit and a crane system according to the dependent claims.

[0015] Further embodiments are specified in the dependent claims. According to a first aspect, an operating unit for an operating system for operating a jib slewing crane is provided, comprising:

[0016] at least one motion control element designed to generate a positioning command through manual operation, a communication unit designed to establish a communication link to the crane control unit and a direct or indirect communication link to one or more other control units,

[0017] a control unit that are trained,

[0018] o in order to establish an active communication link to a crane control unit by operating an activation control element using the communication unit and to transmit positioning commands depending on the operation of at least one movement control element, and

[0019] o in order to communicate a signal, depending on the operation of the activation control element, that a separate takeover of the active communication connection to the crane control unit is desired.

[0020] According to another aspect, an operating system for operating a jib slewing crane is provided, comprising:

[0021] a crane control unit that is fixedly arranged in the jib slewing crane and is designed to control one or more drives of the jib slewing crane in accordance with positioning commands in order to move a load or a load hook;

[0022] several mobile control units, each comprising:

[0023] o at least one motion control element designed to generate a positioning command through manual operation,

[0024] a communication unit that is designed to provide an active communication link to the crane control unit and to establish a direct or indirect communication link to one or more of the other operating units,

[0025] o a control unit that are trained,

[0026] ■ to establish an active communication link between the crane control unit and one of the operating units by using the communication unit and an activation control element, and to transmit positioning commands depending on the operation of at least one movement control element, and

[0027] ■ to communicate a signal, depending on the operation of the activation control element, that a separate takeover of the active communication link to the crane control unit is desired.

[0028] According to another aspect, a method for operating a control unit for an operating system for operating a jib slewing crane is provided, comprising the following steps:

[0029] - Establishing an active communication link with a crane control unit depending on the operation of an activation control element and transmitting positioning commands depending on the operation of the control unit, and

[0030] Communicating a signal that taking over the active communication link to the crane control unit is desired, depending on the operation of the activation control element.

[0031] According to another aspect, a method for operating an operating system for a jib slewing crane is provided, wherein the operating system comprises several of the above-mentioned mobile operating units separate from the jib slewing crane for manually specifying control commands for the crane control and a crane control unit that is fixedly arranged in the jib slewing crane, comprising the following steps: - Establishing an active communication link with the crane control unit depending on the operation of an activation control element and transmitting control commands depending on the operation of the operating unit, and

[0032] Communicating a signal that taking over the active communication link to the crane control unit is desired, depending on the operation of the activation control element.

[0033] The above procedures relate to the operation of a control unit and a control system, which is implemented with a control system comprising at least two mobile control units. The load hook or a suspended load can be transported by a first crane operator with a first control unit from a starting position to the area, in particular the line of sight, of a second crane operator with a second control unit. The system allows the load to be moved within the working area by each control unit by actuating a suitable motion control element of the respective control unit. The motion control element can, for example, comprise one or more joysticks that can be operated by the crane operator. The motion control element enables horizontal movement of the load and raising and lowering of the load rope to move the load hook or load in a vertical direction.

[0034] The operating units are similar or structurally identical and can establish a communication link with a stationary crane control unit of the jib slewing crane in order to transmit command signals or positioning commands to the crane control unit according to the operation of the operating unit, so that the crane control unit converts the command signals or positioning commands into movements / controls of crane elements of the jib slewing crane.

[0035] Furthermore, the control unit can be configured to disconnect an active communication link to a crane control unit via the communication unit. An active communication link between an operator unit and the crane control unit is understood here to mean that signals and control commands are transmitted via a communication channel and implemented in the crane control unit. An inactive communication link can occur through an interruption of the communication channel or a blocking of the execution and implementation of control commands in the crane control unit.

[0036] The crane control unit is designed so that only one active communication link with each operator unit is permitted at a time. This ensures that the crane can only be operated from one operator unit at a time. If a crane operator deactivates the communication link between the operator unit and the crane control unit, in particular by disconnecting or sending a deactivation signal to the crane control unit, the crane control unit may be configured to stop or slow down the ongoing movement of the load or load hook. The crane control unit is then ready to establish a new active communication link with the same or a different operator unit.

[0037] The additional control unit can then establish the communication link by activating it, in particular by establishing a communication link with the crane control unit or by sending a takeover signal to the crane control unit, and thus take over operation of the crane. Using the corresponding movement control element of the additional control unit, the load or the load hook can then be moved in a known manner in a horizontal and / or vertical direction.

[0038] It may be provided that the operating unit includes a signaling element configured to output a perceptible output at the operating unit, wherein the control unit is configured to receive a signal indicating that a takeover of the active communication link by another operating unit is desired and, depending on the reception of the signal, to output a perceptible output via the signaling element.

[0039] The transfer of crane control between operating units can be supported by various functions. For example, an operating unit can be signaled that a communication channel to the crane control unit is open or available, enabling it to establish a communication connection. This signal can trigger a haptic, visual, or audible output perceptible to the crane operator. The crane operator can then operate the control unit accordingly to establish the communication connection to the crane control unit and take over control of the load movement. In this way, a first crane operator can safely move the load to a specific position (as it remains within the first operator's line of sight) and then terminate the communication connection to the crane control unit. This is then signaled to the second crane operator, who can establish a communication connection to the crane control unit using the second operating unit.

[0040] Alternatively or additionally, the first crane operator (with the active control unit) can indicate, via a suitable signal, that the communication link to the crane control unit will soon terminate and the second operator should be ready to establish a communication link. This reduces the time during which neither control unit is actively operating the crane.

[0041] Since the first and second crane operators typically do not have direct line of sight, the control units can use a communication link to signal that their own communication link is active, being deactivated, and / or that a takeover of crane control from another control unit is requested or desired. The communication link can be a direct connection or an indirect connection via the crane control unit. This enables communication between the first and second control units regarding status information, requests, or a takeover of crane operation.

[0042] If a first operating unit has an active communication link to the crane control unit, the second operating unit can send a request to establish a communication link to the first operating unit by pressing the activation button. This request can be made, for example, by the second crane operator as soon as they have a clear view of the suspended load. This request does not result in the second operating unit establishing an active communication link as long as the first operating unit has an active communication link and maintains its connection to the crane control unit.

[0043] However, if the active communication link between the crane control unit and the first operating unit is deactivated by the crane operator, or if the communication link with the first operating unit is terminated in any other way, the communication link between the second operating unit and the crane control unit can be established manually by operating the second operating unit or, if a request to take over the active communication link has been made beforehand, automatically, so that the second crane operator can immediately take over control of the load. This reduces waiting times when an operating unit takes over load control.

[0044] The automatic establishment of the communication link between the second control unit and the crane control unit can be delayed by, for example, 1 to 3 seconds, giving the second crane operator time to prepare to take over control of the load. During this time, the impending transfer of control over the load can be announced on the first and / or second mobile control unit by a haptic, visual, or audible signal. After the second crane operator has taken over control of the load, they can manually control it by operating the movement control element on the second control unit.

[0045] It may be provided that a further signaling element is arranged externally to the operating units within the working area of ​​the jib crane, wherein the control unit is configured to communicate the signal indicating that the active communication link should be taken over by the further operating unit, and wherein the crane control unit is configured to output a perceptible signal, in particular a visual or acoustic output, via the further signaling element, depending on the reception of the signal. The further signaling element may, for example, be configured as a signal light on the tower or on the jib, which can be seen by the crane operators from any position within the working area.

[0046] Furthermore, the control unit can be designed to determine a position of the mobile operating unit relative to the jib slewing crane using a position determination system and to communicate this to the crane control, and to transmit positioning commands to the jib slewing crane depending on the operation of at least one movement control element, which instruct a crane control unit to automatically move a load hook or an attached load in the direction of the determined position.

[0047] Furthermore, an automatic function can be implemented in the control unit, enabling the second control unit to determine its own position within the crane's working area, e.g., through a geopositioning system that includes, for example, a GNSS module such as GPS or similar, whereby the control unit in question instructs the crane control unit to automatically move the load to its own position. (Brief description of the drawings)

[0048] The embodiments are explained in more detail below with reference to the accompanying drawings. These show:

[0049] Figure 1 shows a schematic representation of a crane system with two control units; and

[0050] Figure 2 is a flowchart illustrating the sequence of movements of an attached load from a starting position to a target position using two control units.

[0051] Description of embodiments

[0052] Fig. 1 shows a tower crane 1 with a tower 2 to which a jib 3 is attached. The jib can be rotated about a pivot axis D that runs inside the tower 2. A trolley 4 is mounted on the jib 3 and is movable along its length. A load rope 5 with a load hook 6 at its lower end can be guided over the trolley 4. A load 7 can be attached to the load hook 6.

[0053] The trolley 4 can be moved along the jib 3 so that a horizontal position for a suspended load 7 or the load hook 6 within the working area can be determined by a rotational position and a jib position of the trolley 4. Instead of the trolley 4 on the jib 3, the jib 3 can also be luffing to adjust the distance of the suspended load rope 5 from the tower 2 or from the axis of rotation D. The length of the unwound load rope 5 determines the vertical position of the load hook 5 or the suspended load 7.

[0054] The rotation of the boom 3 about the axis of rotation D and the movement of the trolley 4 can be controlled by suitable crane actuators, e.g., a slewing drive 8 for setting the rotational position and a trolley drive 9 for moving the trolley 4 and setting the trolley position. The load rope 5 can be raised or lowered by means of a load rope drive 10.

[0055] The crane actuators can be controlled in a manner known per se via a suitable crane control unit 15. The crane typically has a cabin 11 in which an operating system is implemented. This operating system allows a crane operator in the cabin to control the crane via operating inputs and to move the load by appropriately controlling the crane actuators.

[0056] To enable a crane operator outside the cabin to move a load, mobile control units 20, 20a, 20b can be provided, each of which can establish a communication link K with the crane control unit 15 to transmit positioning commands and other information. Thus, instead of being controlled by the operating system in the cabin, the crane 1 can also be controlled by receiving positioning commands or command signals from one of the control units 20a, 20b, allowing the load hook 6 or the attached load 7 to be moved within the working area.

[0057] The operating units 20 include a communication unit 21 to transmit control commands or command signals to the crane control unit 15. The control commands correspond to instructions for manual operation of the operating unit 20 and specify the current movement of the crane actuators.

[0058] The control units 20 may further provide one or more movement control elements 22 in the form of a joystick or the like, so that by operating them a direction and a movement speed of the load hook 6 or the attached load 7 can be specified, or the crane operator can specify movements of the crane, i.e. the boom 3, the load rope 5 and the trolley 4, in order to transport an attached load 7.

[0059] The operation of crane 1 is carried out exclusively by controlling the crane actuators via the crane control unit 15. The crane control unit 15 can establish or actively use communication links to exactly one of the operating units 20, so that the operation of crane 1 can be controlled via the respective operating unit 20.

[0060] In some applications, it is necessary to transport a suspended load between two positions that are not connected by a direct line of sight. For this purpose, a first crane operator with the first control unit 20a can be located at or near a starting position S of the load 7, and a second crane operator with a second control unit 20b can be located at or near a target position Z. To transport the load 7, the first crane operator can then use the first control unit 20a to move the load 7 to a point P where the second crane operator can see the load 7. From this load position, the second crane operator can then take over control of the crane and transport the load to the target position Z.

[0061] The operating units 20a, 20b and the crane control unit 15 are configured such that only one of the operating units 20 is permitted to control the crane. This can be ensured, for example, by allowing only one of the operating units 20a, 20b to establish a communication link with the crane control unit 15, while other communication links are blocked. Alternatively, communication links can exist between all operating units 20a, 20b and the crane control unit 15, but only one of the operating units 20a, 20b can transmit valid control commands to the crane control unit 15, which then executes them. Alternatively, communication links can exist between all operating units 20a, 20b and the crane control unit 15, but control commands from only one of the operating units 20a, 20b are executed in the crane control unit 15.

[0062] An important element of the above load transport system is that the second crane operator can recognize when they are authorized to take over control of the load transport and when operation is to be handled by another control unit. For this purpose, it is provided that, either via a direct communication link between the control units 20a and 20b, or indirectly via the crane control unit 15, each control unit 20 signals whether it is active, deactivated, or whether crane control may be taken over by the respective control unit 20, since the crane control unit 15 currently does not use an active communication link to a control unit 20. For this purpose, the control units 20 have a control unit 23 and a signaling element 24.

[0063] The control unit 23 performs a function to determine whether another operating unit 20 is currently controlling the crane. This can be done by sending a corresponding request to the crane control unit 15.

[0064] Furthermore, the control unit 23 can perform a function whereby the signaling element 24 indicates that control of the crane can / should be taken over by the respective operating unit 20. Thus, it is possible for the first crane operator to move an attached load 7 from a starting position S to a raised position P using the first operating unit 20a. By operating the operating unit 20a accordingly, the crane operator can signal that control should be taken over by another operating unit 20. To do this, the first crane operator can deactivate the first operating unit 20a, so that no active crane control is performed by the first operating unit 20a. This can be signaled to the second operating unit 20b, so that the second crane operator is prompted to take over the operation of crane 1.Since the attached load 7 is within the line of sight of the second crane operator, he can establish the active communication link to the crane control unit 15 and control the crane 1 to transport the attached load to the target position Z.

[0065] The takeover of active crane control by an operating unit 20 can be effected by manually actuating a corresponding activation control element 25, thus preventing unintentional takeover of crane control by an operating unit 20. If the activation control element 25 is actuated to take over active crane control, the takeover only occurs if no other communication link is active or no valid commands have been issued by another operating unit. If the activation control element 25 or any other control element is actuated to terminate active crane control, the load can be stopped immediately at its current position to prevent uncontrolled load movement.

[0066] A request to allow a specific control unit to take over crane operation can be made via control units 20. For example, a haptic, visual, or acoustic signal can be issued in the form of a vibration, a light signal, or a beep. Such a request can be generated by a crane operator with an inactive control unit (without an active communication link) and transmitted to the other control units or crane operators. Alternatively, this signal can also be issued elsewhere, e.g., on the crane itself or at another location within the work area.

[0067] The flowchart in Figure 2 briefly explains, by way of example, the procedure for transporting a load using the operating system described above.

[0068] In step S1, the first crane operator takes over the crane control with the first operating unit 20a by establishing an active communication connection with the crane control unit 15.

[0069] In step S2, the first crane operator controls the transport of the load 7 from the starting position S to a transfer position P by actuating the movement control element 22 on the first control unit 20a.

[0070] In step S3, the first crane operator receives a signal at the first control unit 20a indicating that the load is within the line of sight of the second crane operator. The second crane operator then activates a corresponding movement control element 22 at the second control unit 20b.

[0071] Now, in step S4, the first crane operator can deactivate the active communication link, thus enabling the takeover of crane control by another operating unit 20b. The movement of the crane actuators is stopped.

[0072] In step S5, the availability of the communication link to the crane control unit 15 is signaled to the second crane operator.

[0073] In step S6, the second crane operator can then establish the active communication connection to the crane control unit 15 by pressing the activation control element 25.

[0074] In step S7, the crane operator can now take over the transport of the load by operating the second control unit 20b and transport the load to the target position.

[0075] The transport of load 7 can also be automated by the second control unit 20b. For this purpose, the control unit 20 can have a position determination system 26, which makes it possible to determine a relative position of the control unit 20 to the crane 1. This allows the crane control system, knowing the current load position, to determine a load trajectory in a known manner and automatically move the load to the target position Z or to the position of the respective control unit 20. The position determination system 26 can, for example, be a GNSS position determination system.

Claims

Claims 1. Control unit (20, 20a, 20b) for an operating system for operating a jib slewing crane (1), comprising: at least one motion control element (22) configured to generate a positioning command by manual operation, a communication unit (21) configured to establish a communication link (K) to the crane control unit (15) and a direct or indirect communication link to one or more further control units (20, 20a, 20b), a control unit (23) configured o in order to establish an active communication link to a crane control unit (15) using the communication unit (21) and subsequently to transmit positioning commands depending on the operation of the at least one movement control element (22), and o to communicate a signal, depending on the operation of an activation control element (25), indicating that a separate takeover of the active communication link to the crane control unit (15) is desired.

2. Control unit according to claim 1, comprising a signaling element (24) configured to output a perceptible output at the control unit (20, 20a, 20b), wherein the control unit (23) is configured to receive a signal indicating that a takeover of the active communication link by another control unit (20, 20a, 20b) is desired and, depending on the reception of the signal, to output a perceptible output via the signaling element (24).

3. Control unit according to claim 2, wherein the signaling element (24) is configured to output a haptic, visual, or acoustic signal as the perceptible output.

4. Control unit according to any one of claims 1 to 3, wherein the control unit (23) is configured to disconnect an active communication connection to a crane control unit (15) by means of an operation using the communication unit (21).

5. Control unit according to one of claims 1 to 4, wherein the control unit (23) is configured to determine a position of the mobile control unit (20, 20a, 20b) relative to the jib slewing crane (1) using a position determination system and to communicate this position to the crane control, and to transmit positioning commands to the jib slewing crane (1) depending on the operation of the at least one movement control element (22), which instruct a crane control unit (15) to automatically move a load hook or an attached load (7) in the direction of the determined position.

6. Control unit according to one of claims 1 to 5, wherein, upon receiving corresponding information, the signaling element (24) provides a perceptible output indicating that a communication channel for communication with the crane control unit (15) is occupied or unavailable, so that establishing a communication connection is not possible, or is open or available to indicate that a communication connection can be established.

7. Control unit according to one of claims 1 to 6, wherein the control unit is designed with a deactivation control element in order to provide or communicate a signal to another control unit, or to communicate that the communication connection of its own control unit to the crane control will be terminated immediately or shortly, in particular within a given period of between 1 and 10 seconds, and that a taking over crane operator should be ready to establish the communication connection to the crane control with his control unit.

8. Operating system for operating a jib slewing crane (1), comprising: a crane control unit (15) which is fixedly arranged in the jib slewing crane (1) and is configured to control one or more drives (8, 9, 10) of the jib slewing crane (1) in accordance with positioning commands in order to move a load (7) or a load hook; several mobile control units (20, 20a, 20b), each comprising: o at least one motion control element (22) which is configured to generate a positioning command by manual operation, o a communication unit (21) which is configured to establish a communication link (K) to the crane control unit (15) and a direct or indirect communication link to one or more of the other operating units (20, 20a, 20b), o a control unit (23) which are trained, ■ to establish an active communication link between the crane control unit (15) and one of the operating units (20, 20a, 20b) using the communication unit (21) and to transmit positioning commands depending on the operation of the at least one movement control element (22), and ■ to communicate a signal, depending on the operation of at least one activation control element (25), indicating that an independent takeover of the active communication link to the crane control unit (15) is desired.

9. Operating system according to claim 8, wherein the multiple mobile operating units (20, 20a, 20b) have a signaling element (24) configured to output a perceptible signal at the operating unit (20, 20a, 20b), wherein the control unit (23) is configured to receive a signal indicating that a takeover of the active communication link by another operating unit is desired and, depending on the reception of the signal, to output a haptic, visual, or acoustic signal via the signaling element (24). 10.Operating system according to claim 8 or 9, wherein, when an active communication link is requested between the crane control unit (15) and one of the operating units (20, 20a, 20b), the control unit (23) or the crane control unit (15) is configured to establish the active communication link (K) only if no other active communication link exists between the crane control unit (15) and another operating unit (20, 20a, 20b).

11. Operating system according to one of claims 8 to 10, wherein the crane control unit (15) is configured to stop the crane actuators when an active communication link to the crane control unit (15) is terminated.

12. Operating system according to one of claims 8 to 11, wherein a further signaling element is arranged externally to the operating units (20, 20a, 20b) in the working area of ​​the jib slewing crane (1), wherein the control unit (23) is configured to communicate the signal indicating that a further operating unit wishes to take over the active communication link, and wherein the crane control unit (15) is configured to output a perceptible output, in particular a visual or acoustic output, via the further signaling element, depending on the reception of the signal.

13. Operating system according to any one of claims 8 to 12, wherein the control unit (23) is configured to determine a position of the mobile operating unit (20, 20a, 20b) relative to the jib slewing crane (1) using a position detection system and to communicate this position to the crane control system, and to transmit positioning commands to the jib slewing crane (1) depending on the operation of the at least one movement control element (22), which instruct a crane control unit (15) to automatically move a load hook or an attached load (7) in the direction of the determined position.

14. Operating system according to any one of claims 8 to 13, wherein the crane control unit (15) is configured to stop any ongoing movement of the load or load hook when the active communication link to one of the operating units (20, 20a, 20b) is terminated. to stop immediately or to reduce the speed of the ongoing movement within a specified time period, in particular 1-3 seconds, and then to stop it if no other control unit has taken over the active communication link.

15. Method for operating a control unit (20, 20a, 20b) for an operating system for operating a jib slewing crane (1), comprising the following steps: - Establishing an active communication link with a crane control unit (15) depending on the operation of an activation control element (25) and transmitting positioning commands depending on the operation of the control unit (20, 20a, 20b), and communicating a signal that taking over the active communication link to the crane control unit (15) is desired, depending on the operation of the activation control element (25).

16. Method for operating an operating system for a jib slewing crane (1), wherein the operating system comprises several mobile operating units (20, 20a, 20b) separate from the jib slewing crane for manually specifying commands for the crane control and a crane control unit (15) which is fixedly arranged in the jib slewing crane (1), comprising the following steps: - Establishing an active communication link with the crane control unit (15) depending on the operation of an activation control element (25) and transmitting positioning commands depending on the operation of the control unit (20, 20a, 20b), and communicating a signal that taking over the active communication link to the crane control unit (15) is desired, depending on the operation of the activation control element (25).

Images