METHOD FOR DETERMINING A LOAD, HYDRAULIC LIFTING DEVICE FOR EXECUTING SUCH A METHOD

Description

[0001] The invention relates to a method for determining a load lifted or to be lifted by a hydraulic lifting device with the features of the preamble of claim 1, a control system for a hydraulic lifting device designed for carrying out such a method, and a hydraulic lifting device with such a control system.

[0002] A generic method for determining a load lifted or to be lifted by a hydraulic lifting device is known from EP 1 477 452 B1. In the method described therein for a crane with manually operated or hydraulic boom sections, the crane is first brought into a predetermined position during a sampling phase to weigh a load to be attached to a manual boom section of the crane. This predetermined position may be suitable for load handling. Subsequently, with the manually operated boom section attached to the crane, pressure measurements are taken on the main cylinder for various, specifically at least two, positions of the hydraulic boom sections between fully retracted and fully extended hydraulic boom sections, and a sample diagram for this predetermined crane position is created from these measurements. This sampling phase takes place at the crane manufacturer's premises.

[0003] In a further phase, a load attached to a manually operated boom section is determined. For this purpose, the unloaded crane is moved into the specified position suitable for load handling. A pressure measurement in the main cylinder and a comparison with the reference diagram for this position determines the location of the lifting point for the load (length of the load arm). After the load is attached, the load can be determined from the difference between the measured pressure in the unloaded and loaded states of the crane.

[0004] A disadvantage of this method, known in the prior art, is that load determination can only be carried out in a predetermined position of the crane. Before picking up a load, the crane must be positioned according to a sample diagram recorded by the crane manufacturer. Similarly, after picking up a load, the crane must remain in the corresponding position for load determination. Furthermore, load determination can only be performed with the crane configuration (equipment) in which the sample diagram was recorded by the crane manufacturer during the sampling phase. Therefore, if the crane configuration or equipment is modified, the sample diagrams recorded by the crane manufacturer may no longer be applicable for load determination.

[0005] EP 2 982 635 A1 discloses a method according to the preamble of claim 1.

[0006] The object of the invention is to provide a method for determining a load lifted or to be lifted by a hydraulic lifting device, in which the aforementioned disadvantages do not occur.

[0007] This problem is solved by a method having the features of claim 1 and by a hydraulic lifting device having the features of claim 16. Advantageous embodiments of the invention are defined in the dependent claims.

[0008] As with generic methods for determining a load lifted or to be lifted by a hydraulic lifting device, for example in the form of a hydraulic loading crane, the lifting device is first brought into a reference position in a reference phase. The lifting device may be in a first load state during this phase.

[0009] In contrast to methods known in the prior art, the method according to the invention now performs a first measurement of the forces currently acting on the lifting device and its current geometry in the reference position of the reference phase. By measuring these forces and geometry, the current crane configuration or equipment and the current geometry (position) of the lifting device can be taken into account when determining the position of a lifted or to-be-lifted load. This also allows the current (initial) load state of the lifting device to be considered. In other words, it is possible to determine the position of a lifted or to-be-lifted load based on the currently prevailing operating parameters of the lifting device.For example, currently prevailing operating parameters of the lifting device can be recorded as a starting point for determining a lifted or to-be-lifted load.

[0010] In the method according to the invention, this is followed by a measurement phase in which the lifting device is in a second load state and is brought into a measurement position. In the measurement position, a second measurement is taken of the forces currently acting on the lifting device and the current geometry of the lifting device. Analogous to the first measurement, a determination of a lifted or to-be-lifted load can be made by taking into account the currently prevailing operating parameters of the lifting device.

[0011] In a comparison phase following the initial and second measurements of the forces acting on the lifting device and its geometry, the lifted load is characterized by comparing the respective measured forces acting on the lifting device and its current geometry. Since the comparison of the measured forces and geometries (positions) is based on the currently prevailing operating parameters, the lifted or to-be-lifted load can be characterized very precisely. For example, the measurement phase can be carried out immediately after the reference phase, allowing any differences in the measured forces observed during the comparison phase to be directly attributed to a change in the load state of the lifting device. Changes in the measured or prevailing geometry can also be taken into account when characterizing the load.

[0012] To determine the load lifted or to be lifted by the lifting device, one is therefore not dependent on a sampling phase to be carried out by the crane manufacturer and the associated, limitedly applicable sample diagrams as defined by the prior art. For the crane manufacturer itself, the time-consuming sampling phase can be eliminated by means of a method according to the invention. For example, a method according to the invention can also easily take into account aging and wear phenomena of the lifting device when determining the load lifted or to be lifted by the lifting device.

[0013] It should not be ruled out that the measurement phase can be carried out essentially any number of times after the reference phase.

[0014] According to the invention, the reference position corresponds to a freely selectable position of the lifting device.

[0015] The procedure can therefore be carried out from essentially any position of the lifting device. This makes it possible to avoid having to move the lifting device into a predetermined position specifically before the reference phase.

[0016] It can generally be advantageous for the measuring position to correspond to the position of the lifting device after a load has been picked up or dropped. The measuring position can correspond to the position of the lifting device immediately after picking up or dropping a load. The measuring position can also correspond to a position of the lifting device resulting from a (possibly minor) change in position directly after a load has been picked up or dropped.

[0017] It can be advantageous for the measurement position to correspond to a position of the lifting device that approximates its reference position. This allows differences in the measured forces that arise during the comparison phase to be largely attributed to changes in the load state of the lifting device caused by the lifted or to-be-lifted load. Changes in the measured forces due to a change in geometry, for example, due to a change in the support structure, can contribute less in this case. The measurement position can be brought closer to the reference position, for example, by moving the lifting device out of the reference position to pick up or drop off a load and then returning it to the reference position for the measurement phase.

[0018] It can be advantageous for the measuring position of the lifting device to essentially correspond to the reference position. This allows any differences in the measured forces during the comparison phase to be attributed primarily to changes in the load state of the lifting device caused by the lifted or to-be-lifted load.

[0019] It can be further advantageous for the reference position to correspond to a position approximating an intermediate position, where the intermediate position is a position of the lifting device suitable for load picking up or dropping off. This can be beneficial, for example, if the position of the lifting device in which a lifted load is to be determined is not suitable for load picking up or dropping off. This also allows the reference and measuring positions to be located away from the intermediate position suitable for load picking up or dropping off.

[0020] It can be advantageous if the transfer of the lifting device from the reference position to the intermediate position and the transfer of the lifting device from the intermediate position to the measuring position is carried out with a change in position of the lifting device that falls within a tolerance range. When the position of the lifting device changes within the tolerance range, the forces and geometry recorded in the reference phase can still be used to determine the lifted or to-be-lifted load in the measuring phase. Thus, after the reference phase, essentially any position change of the lifting device within the tolerance range can be carried out without having to repeat the reference phase before the measuring phase. During the measuring phase, the measuring position can also deviate from the reference position within the tolerance range.

[0021] It can be advantageous to perform a reference phase to record the forces and geometry acting on the lifting device in the first load state before each measurement phase to record the forces and geometry acting on the lifting device in the second load state. In other words, the reference phase is intended to be performed before each load application or release by the lifting device. The measurement phase can be performed essentially any number of times after the reference phase. It should also be possible to perform the measurement phase any number of times after a change in the position of the lifting device that falls within the tolerance range.

[0022] It may be possible to record the forces currently acting on the lifting device and its current geometry by incorporating parameters characteristic of the respective position and load state of the lifting device, as well as a calculation model. These characteristic parameters can correspond to the forces acting on the lifting device and its geometry. The calculation model can also include information about the lifting device, such as its possible and current configuration and equipment.

[0023] The lifting device can have at least one crane column rotatable about a vertical axis of rotation and a main arm pivotably mounted on the crane column about a first horizontal pivot axis. Furthermore, the lifting device can have at least one hydraulic main cylinder for pivoting the main arm, whereby the moment with respect to the first horizontal pivot axis is recorded during the reference and measurement phases. In a simple case, for example, the moment with respect to the first horizontal pivot axis can be determined by taking into account the pivot angle and the length of the main arm as well as the pressure measured in the main cylinder.

[0024] The lifting device may further include a slewing mechanism for rotating the crane column and a knuckle boom pivotably mounted on the main arm about a second horizontal axis of rotation, preferably with at least one crane extension arm. The lifting device further includes a first hydraulic cylinder for pivoting the knuckle boom and preferably at least one hydraulic cylinder for actuating the at least one crane extension arm. Such a configuration may be found, for example, when the lifting device is designed as a knuckle boom crane.

[0025] When recording the forces currently acting on the lifting device and its current geometry, it may be provided that the characteristic parameters include at least the pressure in the at least one main cylinder and / or the pressure in the articulated cylinder and / or the rotation angle of the slewing mechanism and / or the articulation angle of the main arm relative to the crane column and / or the articulation angle of the articulated arm relative to the main arm and / or the extension position of the at least one crane extension arm. By appropriately selecting the characteristic parameters, the forces and the geometry can be recorded completely and accurately.

[0026] It can be further advantageous for the lifting device to have a knuckle boom attachment mounted pivotably on the knuckle boom about a third horizontal pivot axis, with at least one crane extension arm. The lifting device further comprises at least a second hydraulic articulation cylinder for pivoting the knuckle boom attachment and a second hydraulic extension cylinder for actuating the at least one crane extension arm. The characteristic parameters further include the pressure in the second articulation cylinder and / or the articulation angle of the knuckle boom attachment relative to the knuckle boom and / or the extension position of the at least one crane extension arm of the knuckle boom attachment. Such a configuration can be found, for example, when the lifting device is designed as a knuckle boom crane with a knuckle boom attachment. It can be provided that the moment with respect to the first horizontal pivot axis and the moment with respect to the third horizontal pivot axis are recorded during the reference phase and the measurement phase.With appropriate geometry measurement, the lifted or to-be-lifted load can also be determined by measuring only the moment about the first horizontal pivot axis. However, by additionally measuring the moment about the third horizontal pivot axis, it may be possible to characterize the lifted or to-be-lifted load more precisely.

[0027] Furthermore, it can be advantageous if the lifting device has at least one boom extension, and if the calculation model includes the additional extension of this boom. Data relevant to the boom extension can be stored in the calculation model. Such a boom extension, which may be manually operated, can be used to increase the reach of a crane arm or boom of the lifting device. The boom extension can be positioned at a predefined angle on a crane arm or boom of the lifting device, for example, by means of an adjustment mechanism.

[0028] Furthermore, it can be advantageous for the lifting device to include at least one working device arranged on it, particularly on a crane extension arm, and for the additional load caused by the working device to be included in the calculation model. A working device, such as a winch, can be arranged at essentially any point on the lifting device. A working device, such as a grab, can also be arranged on a crane extension arm of the lifting device. Data relevant to the working device can be stored in the calculation model, but this is not mandatory. By recording the forces momentarily acting on the lifting device in the first load state and the current geometry of the lifting device, the working device and, if applicable, its position on or relative to the lifting device can be taken into account in determining the lifted or to-be-lifted load.

[0029] It can be advantageous to include the deformation of the lifting device in the calculation model. Deformation of the lifting device caused by its own weight and / or the lifted or to-be-lifted load can influence the actual geometry of the lifting device in a given position or load condition. Including the deformation of the lifting device in the calculation model allows for a more accurate determination of the lifted or to-be-lifted load.

[0030] It can be advantageous to include the deformation of the crane column and / or the main arm and / or the knuckle arm and / or at least one crane extension arm of the lifting device in the calculation model, thereby allowing for a better characterization of the actual geometry of the lifting device in a given position or load condition. Similarly, including the influence of sealing friction in the hydraulic cylinders can allow for a more precise determination of the lifted or to-be-lifted load.

[0031] It can be advantageous for the calculation model to apply the deformation as a correction to the recorded buckling angles and / or as a correction to the recorded shear positions, and / or to apply the influence of sealing frictions as a correction to the recorded pressures. This allows, for example, the deformation resulting from a specific position of the lifting device and the hydraulic pressure resulting from a specific load condition or position to be taken into account in the calculation model.

[0032] Furthermore, it can be advantageous for the correction to be based on the measured forces currently acting on the lifting device, and / or the measured buckling angles, and / or the measured thrust positions. This allows not only for position- or geometry-dependent deformation of the lifting device to be taken into account, but also (possibly in combination) for the load being lifted or to be lifted. Deformation caused by the design or configuration of the lifting device can also be considered. In other words, the extent of the corrections can itself be dependent on the measured parameters.

[0033] It can also be advantageous that the correction for the deformation is linearly dependent on the detected pressure and / or on the detected thrust position and / or that the correction for the sealing frictions is inversely proportional to the detected pressure and depends on a direction of a change in position.

[0034] It can be stipulated that the first load condition corresponds to a load condition without a load lifted by the lifting device, and the second load condition corresponds to a load condition with a lifted load. The reference phase would thus be carried out without a lifted load, and the measurement phase would be carried out after a load has been lifted.

[0035] However, it should not be ruled out that the first load condition corresponds to a load condition with a first load lifted by the lifting device, and the second load condition corresponds to a load condition with a second, preferably different, lifted load. The reference phase would thus, for example, be carried out with a load that has already been lifted, and the measurement phase would take place after partially releasing or additionally picking up a load.

[0036] As already mentioned at the beginning, protection is also sought for a control system for a hydraulic lifting device, which is designed to carry out a procedure as described above for determining a lifted or to-be-lifted load.

[0037] In a first operating mode, such a control system can perform the reference phase in a first load state in the reference position of the lifting device to first detect the forces currently acting on the lifting device and the current geometry of the lifting device.

[0038] In a second operating mode of the control system, the measurement phase can be performed under a second load condition in the measuring position of the lifting device to record the forces currently acting on the lifting device and its current geometry. The control system can, for example, be designed such that it automatically switches to the second operating mode after the reference phase in the first operating mode has been completed. It can also be provided, for example, that the position of the lifting device in the second operating mode can only be changed within the tolerance range, or that a corresponding warning signal is issued by the control system before the position exceeds the tolerance range.

[0039] In a third operating mode of the control system, the comparison phase for characterizing the lifted load can be performed by comparing the respective measured forces currently acting on the lifting device with the respective measured current geometry of the lifting device. For example, it can be provided that after the measurement phase, the system automatically switches to the third operating mode and, if necessary, also performs the comparison phase automatically.

[0040] It can be advantageous that the load characterized in the comparison phase can be displayed in units corresponding to the load on a display that communicates with the controller. This allows, for example, a user to be given information about the load determined by the process in units that are understandable to them.

[0041] As already mentioned, protection is ultimately also required for a hydraulic lifting device with a control system as previously described. The hydraulic lifting device can be designed as a loading crane for a vehicle. A knuckle boom crane can be particularly advantageous for the hydraulic lifting device.

[0042] Further details and advantages of the present invention are explained in more detail below with reference to the exemplary embodiments shown in the drawings, as described in the figures. These show: Figs. 1a to 1c Side views of various designs of a lifting device mounted on a vehicle, Figs. 2a to 2c Side views of various designs of a lifting device, Figs. 3a and 3b Side views of various designs of a lifting device and each a schematic representation of a control system with sensors, Figs. 4a to 4c A schematic representation of a lifting process sequence, Figs. 5a to 5c Another schematic representation of a lifting process sequence, Figs. 6a and 6b Another schematic representation of a lifting process sequence, Figs. 7a and 7b Schematic representations of various designs of a lifting device and each a representation of the tolerance range, Figs. 8a and 8b Schematic representations of various designs of a lifting device with boom extension, Figs. 9a and 9b Schematic representations of various designs of a lifting device with a working tool and Fig.Figures 10a and 10b show schematic representations of different designs of a lifting device, each with a winch arranged in different positions.

[0043] In Figure 1a A first embodiment of the lifting device 2 is shown, wherein the lifting device 2 is designed as a loading crane or knuckle boom crane and is arranged on a vehicle 19. As shown, the lifting device 2 has a crane column 3 rotatable about a first vertical axis v1 by means of a slewing mechanism 18, a main arm 4 pivotally mounted on the crane column 3 about a first horizontal pivot axis h1, and a knuckle arm 5 pivotally mounted on the main arm 4 about a second horizontal pivot axis h2, with at least one crane extension arm 6. A hydraulic main cylinder 15 is provided for pivoting the main arm 4 relative to the crane column 3 (kneeling angle a1). A hydraulic knuckle cylinder 16 is provided for pivoting the knuckle arm 5 relative to the main arm 4 (kneeling angle a2).

[0044] In Figure 1b A second embodiment of the lifting device 2 is shown, wherein the lifting device 2 shown therein is additionally equipped with the following: Figure 1a The embodiment shown has a forward-facing articulated arm 7, pivotable about a third horizontal pivot axis h3 on the crane push arm 6 of the articulated arm 5, with a crane arm 10 and a further crane push arm 11. A pivoting cylinder 17 is provided for pivoting the forward-facing articulated arm 7 relative to the articulated arm 5 (articulation angle a3).

[0045] In Figure 1c A third embodiment of the lifting device 2 is shown, wherein the lifting device 2 shown therein, in addition to the configuration of the in Figure 1bThe embodiment shown has a further extension arm 12 pivotable about a fourth horizontal pivot axis a4 on the crane push arm 11 of the extension arm 7. A pivot cylinder 20 is provided for pivoting the further extension arm 12 relative to the extension arm 7 (bending angle a4).

[0046] All versions shown can of course feature a rotary mechanism 18.

[0047] In the Figures 2a to 2c Each is a detailed view of one according to the Figures 1a to 1c trained lifting device 2 shown.

[0048] In Figure 3a is an embodiment of the lifting device 2 according to the Figure 1a or 2a. Furthermore, a schematic representation of a control system 1 is shown, which is used to carry out a procedure for determining a load 21 that is lifted or to be lifted by the lifting device 2 (not shown here, see for example [reference]). Figures 4 , 5 or 6) is shown. The controller 1 has several signal inputs to which signals from the sensors installed on the lifting device 2 can be fed. Furthermore, the controller 1 has a memory 9 in which, for example, program data for operating modes and calculation models of the controller 1 as well as incoming signals can be stored, and a processing unit 8 with which incoming signals and data stored in memory 9 can be processed. The controller 1 can also communicate with a display 22. Communication between the controller 1 and the display 22 can be wired and / or wireless. The sensors for detecting the geometry of the lifting device 2 comprise, in the Figure 3aThe illustrated embodiment includes a rotation angle sensor d1 for detecting the respective rotation angle d1a, an articulation angle sensor k1 for detecting the articulation angle a1 of the main arm 4 to the crane column 3, an articulation angle sensor k2 for detecting the articulation angle a2 of the articulation arm 5 to the main arm 4, and a thrust position sensor s1 for detecting the thrust position of the crane thrust arm 6. To detect the forces acting on the lifting device 2, a pressure sensor p1 is provided for detecting the hydraulic pressure p1a in the main cylinder 15 and a pressure sensor p2 is provided for detecting the hydraulic pressure p2a in the articulation cylinder 16.

[0049] In Figure 3b is analogous to Figure 3a a version of the lifting device 2 according to the Figure 1bor 2b shown. The configuration of the lifting device 2 comprises, as shown, an attachment articulated arm 7 arranged on the crane push arm 6 of the articulated arm 5. As additional sensors for detecting parameters characteristic of the load state of the lifting device 2, an articulation angle sensor k3 for detecting the articulation angle a3 of the attachment articulated arm 7 to the articulated arm 5, a thrust position sensor s2 for detecting the thrust position of the further crane push arm 11 and a pressure sensor p3 for detecting the hydraulic pressure p3b in the articulation cylinder 17 are provided.

[0050] An analogous version of the one in the Figures 3a and 3b arrangement shown consisting of a lifting device 2 according to the Figure 1c or 2c and a controller 1 is also conceivable.

[0051] In a method as described above for determining a load 21 lifted or to be lifted by the lifting device 2, this load is compared to the Figure 3aAdditional sensors are not strictly necessary when the lifting device 2 is configured with an attached articulated arm 7, since (if the position of the attached articulated arm 7 is known) the lifted or to-be-lifted load 21 can, in principle, be determined by measuring the moment with respect to the first horizontal pivot axis h1. However, the additional sensors and the consideration of the measured values ​​or parameters they provide, in particular the possibility of additionally determining the moment with respect to the third horizontal pivot axis h3, can contribute to increased accuracy of the determination (measurement accuracy).

[0052] In the Figures 4a to 4c The diagram shows the sequence of a load lifting operation (or, in reverse order, the sequence of a load release) by the lifting device 2. The diagram in Figure 4aThe position of the lifting device 2 shown can correspond to the reference position, whereby an essentially freely selectable position of the lifting device 2 can serve as the reference position. Of the parameters characteristic of the load state of the lifting device 2, only the thrust position of the articulated arm 5 measured by the thrust position sensor s1 and the hydraulic pressure in the main cylinder 15 measured by the pressure sensor p1 are considered in the illustrated load-bearing process. In the reference position, the first thrust position x1a of the crane thrust arm 6 and the first hydraulic pressure p1a are measured and stored in the memory 8 of the control unit 1 (not shown). The control unit 1 has a first operating mode for the initial detection of the forces currently acting on the lifting device 2 and the current geometry of the lifting device 2.

[0053] From the reference position, the lifting device is now moved into the intermediate position by a change in geometry, here by extending the crane's extension arm 6 of the knuckle arm 5 into the second extension position x1b. As shown, the intermediate position is suitable for receiving the load 21. Of course, it is also possible that the load in the Figure 4bThe position of the lifting device 2 shown (before lifting the load 21) serves as the reference position. In the intermediate position, the second extension position x1b of the crane extension arm 6 and the second hydraulic pressure p1b are measured and also stored in the memory 8 of the control unit 1 (not shown). This can generally be done for all lifting operations in an intermediate phase in which the control unit 1 is in a suitable operating mode. In the intermediate position, the load 21 is now attached to the lifting device 2 and, if necessary, lifted. In principle, the lifted load 21 can already be determined at this point.

[0054] From the intermediate position, the lifting device 2 is moved into the measuring position by a change in geometry, here after lifting the load 21 by retracting the crane extension arm 6 into the third extension position x1c. The measuring position is approximated to the reference position, as shown. It may be stipulated that a change in position or geometry of the lifting device 2 must lie within a tolerance range in order to use the characteristic parameters recorded in the reference phase for the forces currently acting on the lifting device 2 and the current geometry of the lifting device 2 to determine the lifted load 21. The tolerance range may apply to a maximum permissible change in extension position and / or a maximum permissible change in buckling angle (see, for example, [reference]). Figures 7a and 7b ).

[0055] In Figure 4cAfter lifting the load 21, the lifting device 2 is in the measuring position. In the measuring position, the third extension position x1c of the crane extension arm 6 and the third hydraulic pressure p1c are measured and stored in the memory 8 of the control unit 1 (not shown). The control unit 1 has a second operating mode for the second acquisition of the forces currently acting on the lifting device 2 and the current geometry of the lifting device 2.

[0056] In a comparison phase, in which the controller 1 is in a third operating mode, the lifted load 21 is characterized by comparing the respective detected forces currently acting on the lifting device 2 and the respective detected instantaneous geometry of the lifting device 2. The detection of the forces currently acting on the lifting device 2 and the instantaneous geometry of the lifting device is generally advantageously carried out by including parameters characteristic of the respective position of the lifting device 2 and the respective load state of the lifting device 2 (for example, pressures, thrust positions, buckling angles and any additional configuration data) and a calculation model stored in the memory 8 of the controller 1.

[0057] In the Figures 5a to 5cFigure 2 shows a further sequence of load lifting (or, in reverse order, the sequence of load release) by the lifting device 2. The load lifting of the load 21 by the lifting device 2 occurs, as shown, by pivoting the articulated arm 5 relative to the main arm 4. Of the parameters characteristic of the load state of the lifting device 2, only the articulation angle of the articulated arm 5, measured by the articulation angle sensor k2, and the hydraulic pressure in the main cylinder 15, measured by the pressure sensor p1, are considered in the illustrated sequence of load lifting.

[0058] In the Figure 5a In the reference position shown, the first articulation angle position a21 of the articulated arm 5 and the first hydraulic pressure p1a are measured and stored in the memory 8 of the control unit 1 (not shown) (reference phase, control unit 1 in the first operating mode). By changing the geometry, here pivoting the articulated arm 5, the lifting device 2 is moved into the position shown. Figure 5bThe intermediate position shown is brought into place. In this intermediate position, the second articulation angle position a22 of the articulated arm 5 and the second hydraulic pressure p1b are measured and also stored in the memory 8 of the control unit 1 (not shown). As before, the following can also be used here: Figure 5b The position of the lifting device 2 shown serves as a reference position. By a further change in geometry, here again a pivoting of the articulated arm 5, the lifting device 2 is moved into the position shown. Figure 5c The measuring position shown is brought into place, which also results in the load 21 being lifted. In the measuring position, the third articulation angle position a23 of the articulated arm 5 and the third hydraulic pressure p1c are measured and stored in the memory 8 of the control unit 1 (not shown) (measuring phase control unit 1 in the second operating mode). In the subsequent comparison phase (control unit 1 in the third operating mode), the lifted load 21 can again be characterized by the control unit 1.

[0059] In the Figures 6a and 6b Figure 2 shows a further sequence of load picking up (or, in reverse order, the sequence of load release) by the lifting device 2, wherein the lifting device has an additional working device 14 in the form of a winch arranged on the articulated arm 5. The lifting device 2 picks up the load 21 by means of the working device 14 in the form of a winch. Of the parameters characteristic of the load state of the lifting device 2, only the hydraulic pressure in the main cylinder 15 measured by pressure sensor p1 and the hydraulic pressure in the articulated cylinder 17 measured by pressure sensor p3 are considered in the illustrated sequence of load picking. Figure 6a The lifting device 2 is in the reference position, which is already suitable for load handling. Figure 6bAfter the load has been applied, the lifting device 2 is in the measuring position, which in the illustrated case essentially corresponds to the reference position. By comparing the pressures p1a, p3a recorded in the reference phase and those p1b, p3b recorded in the measuring phase, the change in load on the lifting device 2 can be determined (given a sufficiently defined geometry), and thus the lifted load 21 can be characterized.

[0060] In principle, the method described above makes it possible to determine a lifted or to-be-lifted load by the lifting device 2 in any combination of geometric changes - in particular in any combination of the geometric changes shown in the figures discussed.

[0061] In the Figures 4 , 5 and 6It goes without saying that for each of the positions of the lifting device 2 shown, the instantaneous geometry is recorded – specifically, the characteristic parameters relevant to the instantaneous geometry (e.g., rotation angle, articulation angle, and thrust positions). In versions of the lifting device 2 with an attached jib arm 7, the characteristic parameters recorded for this attached jib arm 7 can also be included in determining the lifted or to-be-lifted load 21.

[0062] In the Figures 7a and 7b Each figure shows a schematic embodiment of a lifting device 2 with manually operated, static boom extensions 13 attached to it.

[0063] In the Figure 7aIn the illustrated embodiment, the boom extensions 13 are arranged on the articulated arm 5. The boom extensions 13 can be pivotally arranged on the articulated arm 5, and the articulation angle of the boom extensions 13 can be detected by means of an articulation angle sensor k3. Information on the additional positioning of the boom extensions 13 can be stored in the memory 8 of the controller 1 and included in the determination of a load 21 to be lifted or already lifted. Figure 7a Furthermore, the tolerance range for the change in thrust position of the knuckle arm 5 and the change in the knuckle angle of the boom extensions 13 is indicated by dashed lines.

[0064] In the Figure 7bIn the embodiment shown, the boom extensions 13 are arranged on a secondary articulated arm 7 located on the articulated arm 5. The boom extensions 13 can be pivotably arranged on the secondary articulated arm 7, and the articulation angle of the boom extensions 13 can be detected by means of an articulation angle sensor k4. Figure 7b The tolerance range for the change in thrust position of the knuckle arm 5, the front knuckle arm 7 and the change in the knuckle angle of the boom extensions 13 is also indicated by dashed lines.

[0065] In a particularly advantageous embodiment of the lifting device 2, the tolerance range can essentially encompass the entire range of motion of the lifting device 2.

[0066] In the Figures 8a and 8b is one of the Figures 7a and 7bAnalogous design of the lifting device 2 is shown, however, the boom extensions 13 are attached to the knuckle arm 5 or to the front knuckle arm 7 at a predetermined, non-variable angle of articulation.

[0067] In the Figures 9a and 9b Each figure shows an embodiment of the lifting device 2 with a working tool 14 attached to it, for example in the form of a gripper. Figure 9a The working device 14 is arranged on the articulated arm 5 and in Figure 9b The working device 14 is arranged on the articulated arm 7. If necessary, the angular position of the working device 14 relative to the crane arm supporting it can be recorded and taken into account when determining a lifted load 21. Since the load on the lifting device 2 caused by the working device 14 is recorded in the reference phase as well as in the measurement phase of the previously described method, it can be included in the calculation model.

[0068] In the Figures 10a and 10bEach figure shows an embodiment of the lifting device 2 with a working device 14 attached to it, here in the form of a winch, and a load 21 lifted by the lifting device 2. Figure 10a The working device 14 is arranged on the articulated arm 5 and in Figure 10b The working device 14 is arranged on the main arm 4. Since the load on the lifting device 2 caused by the working device 14 is recorded in the reference phase as well as in the measurement phase in the previously described procedure, essentially independent of its position on the lifting device 2, it can be included in the calculation model.

[0069] The functionality of determining a load 21 lifted or to be lifted by the lifting device 2 is therefore not limited by the equipment or configuration of the lifting device 2. Reference symbol list:

[0070] 1 Control 2 Lifting device 3 Crane column 4 Main arm a1, a2, a3, a4 Articulation angle 5 Articulated arm 6 Crane push arm 7 Extension arm s1, s2 Push position sensor x1a, x2b, x3c Push positions p1, p2, p3 Pressure sensors p1a, p1b, p1c Pressures p3a, p3b Pressures 8 Memory 9 Computing unit k1, k2, k3, k4 Articulation angle sensor d1 Rotation angle sensor a21, a22, a23 Articulation angle d1a Rotation angle 10 Crane arm 11 Crane push arm 12 Extension arm 13 Boom extension 14 Working device 15 Main cylinder 16, 17, 20 Articulation cylinder 18 Slewing mechanism 19 Vehicle 22 Display h1, h2, h3 Horizontal slewing axis v1 Vertical Swivel axis 21 load

Claims

1. A method for determining a load (21) which is lifted or is to be lifted by a hydraulic lifting apparatus (2), preferably a hydraulic loading crane, wherein the lifting apparatus (2) for determining the load (21) which is lifted or is to be lifted is moved into a reference position in a reference phase in a first loading state of the lifting apparatus (2), characterised in that - in the reference position a first detection of the forces currently acting on the lifting apparatus (2) and the current geometry of the lifting apparatus (2) is effected, wherein the reference position corresponds to a freely selectable position of the lifting apparatus (2), - in a measurement phase the lifting apparatus (2) is moved into a measurement position in a second loading state and in the measurement position a second detection of the forces currently acting on the lifting apparatus (2) and the current geometry of the lifting apparatus (2) is effected, and - in a comparison phase the lifted load (21) is characterised by a comparison of the respective detected forces currently acting on the lifting apparatus (2) and the respective detected current geometry of the lifting apparatus.

2. The method according to claim 1 wherein the measurement position corresponds to a position of the lifting apparatus (2) after a load pickup or a load setdown and / or corresponds to a position of the lifting apparatus (2), approximated to the reference position of the lifting apparatus (2) and / or substantially corresponds to the reference position.

3. The method according to at least one of the preceding claims wherein the reference position corresponds to a position approximated to an intermediate position, wherein the intermediate position is a position of the lifting apparatus (2), that is suitable for load pickup or load setdown, and wherein it is preferably provided that the transfer of the lifting apparatus (2) out of the reference position into the intermediate position and the transfer of the lifting apparatus (2) out of the intermediate position into the measurement position is effected with a change in position of the lifting apparatus (2) being within a tolerance range.

4. The method according to at least one of the preceding claims wherein prior to each implementation of the measurement phase for detecting the forces currently acting on the lifting apparatus (2) in the second loading state and the current geometry of the lifting apparatus (2) an implementation of the reference phase is effected for detecting the forces currently acting on the lifting apparatus (2) in the first loading state and the current geometry of the lifting apparatus (2).

5. The method according to at least one of the preceding claims wherein detecting the forces currently acting on the lifting apparatus (2) and the current geometry of the lifting apparatus (2) is effected with involvement of parameters characteristic of the respective position of the lifting apparatus (2) and the respective loading state of the lifting apparatus (2), and a calculation model.

6. The method according to at least one of the preceding claims wherein the lifting apparatus (2) has at least one crane column rotatable about a vertical axis of rotation (v1) and a main arm (4) mounted pivotably about a first horizontal pivot axis (h1) to the crane column (3), wherein the lifting apparatus (2) further has at least one hydraulic main cylinder (15) for the pivotal movement of the main arm (4), wherein in the reference phase and the measurement phase the moment is detected in relation to the first horizontal pivot axis (h1).

7. The method according to the preceding claim wherein the lifting apparatus (2) has a rotary mechanism (18) for rotating the crane column (3) and an articulated arm (5) mounted pivotably about a second horizontal axis of rotation (h2) to the main arm (4) pivotably about a second horizontal axis of rotation (h2) and with preferably at least one crane extension arm (6), wherein the lifting apparatus (2) further has a first hydraulic articulation cylinder (16) for the pivotal movement of the articulated arm (5) and preferably at least one first hydraulic extension cylinder for actuation of the at least one crane extension arm (6).

8. The method according to claims 5 and one of claims 6 or 7 wherein the characteristic parameters include at least the pressure in the at least one main cylinder (15) and / or the pressure in the articulation cylinder (16) and / or the rotary angle of the rotary mechanism (18) and / or the articulation angle (a1) of the main arm (4) relative to the crane column (3) and / or the articulation angle (a2) of the articulated arm (5) relative to the main arm (4) and / or the extension position of the at least one crane extension arm (6).

9. The method according to at least one of claims 5 to 8 wherein the lifting apparatus (2) further has an attachment articulated arm (7) mounted pivotably about a third horizontal pivot axis (h3) to the articulated arm (5) and having at least one crane extension arm (11), wherein the lifting apparatus (2) further has at least one second hydraulic articulation cylinder (17) for the pivotal movement of the attachment articulated arm (7) and the characteristic parameters further include the pressure in the second articulation cylinder (17) and / or the articulation angle (a3) of the attachment articulated arm (7) relative to the articulated arm (5) and / or the extension position of the at least one crane extension arm (11) of the attachment articulated arm (7), wherein in the reference phase and the measurement phase the moment in relation to the first horizontal pivot axis (h1) and the moment in relation to the third horizontal pivot axis (h3) is detected.

10. The method according to the preceding claim wherein the lifting apparatus (2) further has at least one fly jib (13) arranged on a crane extension arm (6, 11) - preferably at a predeterminable angle - and the additional displacement of the at least one fly jib (13) is incorporated in the calculation model.

11. The method according to at least one of preceding claims 5 to 10 wherein the lifting apparatus (2) further has a working device (14) arranged on the lifting apparatus (2), in particular on a crane extension arm (6, 11), and the additional loading due to the working device (14) is incorporated in the calculation model.

12. The method according to at least one of preceding claims 6 to 11 wherein the deformation of the lifting apparatus (2) is incorporated in the calculation model.

13. The method according to the preceding claim and at least one of claims 6 to 12 wherein the deformation of the crane column (3) and / or the main arm (4) and / or the articulated arm (5) and / or the attachment articulated arm (7) and / or the at least one crane extension arm (6, 11), of the lifting apparatus (2) and / or the at least one fly jib (13) and / or the influence of seal frictions of the hydraulic cylinders (15, 16, 17, 20) are incorporated in the calculation model.

14. The method according to the preceding claim wherein in the calculation model the deformation in the form of a correction to detected articulation angles and / or in the form of a correction to detected extension positions is applied, and / or the influence of the seal frictions is applied in the form of a correction to detected pressures, wherein preferably the correction is effected in dependence on the detected forces currently acting on the lifting apparatus (2) and / or detected articulation angles and / or the detected extension positions, and / or preferably the correction for the deformation is effected in linear dependency in respect of the detected pressure and / or in linear dependency in respect of the detected extension position and / or the correction for the seal frictions is effected inversely proportionally to the detected pressure and in dependence on a direction of a change in position.

15. The method according to at least one of the preceding claims wherein the first loading state corresponds to a loading state without a load (21) lifted by the lifting apparatus (2) and the second loading state corresponds to a loading state with a lifted load (21), or the first loading state corresponds to a loading state with a first load (21) lifted by the lifting apparatus (2) and the second loading state corresponds to a loading state with a second lifted load (21) preferably differing from the first.

16. A hydraulic lifting apparatus (2) - preferably a loading crane for a vehicle (19), particularly preferably an articulated arm crane - having a control means (1) which is adapted for carrying out a method according to at least one of the preceding claims for determining a load which is lifted or is to be lifted, wherein by the control means (1) - in a first operating mode the reference phase can be carried out in a first loading state in the reference position of the lifting apparatus (2) for the first detection of the forces currently acting on the lifting apparatus (2) and the current geometry of the lifting apparatus (2), wherein the reference position corresponds to a freely selectable position of the lifting apparatus (2), - in a second operating mode the measurement phase can be carried out in a second loading state in the measurement position of the lifting apparatus (2) for the second detection of the forces currently acting on the lifting apparatus (2) and the current geometry of the lifting apparatus (2), and - in a third operating mode the comparison phase can be carried out for characterising the lifted load (21) by a comparison of the respective detected forces currently acting on the lifting apparatus (2) and the respective detected current geometry of the lifting apparatus (2), wherein preferably the load (21) characterised in the comparison phase can be displayed at a display means communicating with the control means in units corresponding to the load (21).