EP3169618A1

EP3169618A1 - Fill degree control for a bulk material gripper of a crane

Info

Publication number: EP3169618A1
Application number: EP15739573.2A
Authority: EP
Inventors: Jürgen ROTHMANN; Arno Van De Loo
Original assignee: Terex MHPS GmbH
Current assignee: Konecranes Global Oy
Priority date: 2014-07-17
Filing date: 2015-07-17
Publication date: 2017-05-24
Anticipated expiration: 2035-07-17
Also published as: ES2679624T3; US20170166421A1; CN106604885B; WO2016009040A1; RU2662375C1; BR112016029086A2; DE102014110060A1; EP3169618B1; US10611606B2; CN106604885A

Abstract

The invention relates to a method for filling a gripper (2) for bulk material (14), said gripper being suspended on holding cables (12), raised and lowered by a crane (1) via a controller (17), and acting on the bulk material (14) with the gripper weight during the closing and filling process. By reducing the effect of the weight of the gripper (2) on the bulk material (14), a fill degree of the gripper (2) is influenced via the controller (17) in that a tensile force acting on the holding cables (12) is influenced. The aim of the invention is to provide a method for optimally filling the gripper. This is achieved in that a tensile force TARGET value (Fsoll) is determined for the holding cables (12) via the controller (17); the tensile force TARGET value (Fsoll) is output to a tensile force controller (18) as an input variable; an electric motor (19) for lifting and lowering the gripper (2) is controlled by the tensile force controller (18); and an ascertained tensile force ACTUAL value (Fist) of the holding cables (12) is supplied to the tensile force controller (18) as an input variable.

Description

Filling degree control for a bulk grapple of a crane

The invention relates to a method for filling a gripper for bulk material according to the preamble of claim 1.

It is well known that grabs are used for the handling of bulk materials such as ore, coal, grain, gravel or sand. These grippers, which are also referred to as two or multiple-shell claws, have a size, shape and number of shells which are each optimized with regard to the bulk material to be handled. This ensures that the grippers penetrate well into the bulk material, fill well with the bulk material and can be emptied from this. Usually, the grippers are deposited in an open position on the bulk material, sink over their own weight in the bulk material and during a closing movement, the grippers detect the bulk material and are filled hereby. The grippers are closed hydraulically or via rope drives.

From the German patent DE 199 55 750 B4 a crane with a gripper for bulk material is known. The gripper is designed as a so-called four-rope gripper.

Thus, there are two tethers and two cords which are independently movable to open, close, raise and lower the grab. The holding and closing cables are driven separately via two cable drums. To open the spit, the strikers are relieved and the gripper hangs only on the tethers. The tethers on a

Lever mechanism of the gripper and cause in conjunction with the weight of the gripper, an opening of the gripper. For a filling, the open gripper is placed over the tethers on the bulk material with a slack closing rope. To let the gripper sink into the bulk material under the effect of its own weight, the tether is then released. By tightening the locking cords then the gripper is closed, which fills and then lifted after closing the gripper of the strands. Here then the tethers must be tightened in parallel to avoid slack rope. In the area of lifting the gripper, the forces in the retaining and closing cables are then adjusted to each other again via corresponding controls, so that the

subsequent lifting is done together with the holding and closing cables. Usually, data on the bulk density, the gripper volume and the dead weight of the gripper are not included in a crane control of the crane. Under the harsh operating condition of the gripper, a level of the gripper is taken into account only indirectly by means of empirical values.

From DD 288 138 A5 is already a method for preventing a

Gripper overload of a hanging ropes and closing cables suspended hook known. In this case, during the closing operation, a pulling force acting in the closing cables and in the tethers is measured and their difference compared with a desired value for the tensile force acting in the closing cables. If the difference exceeds a predetermined value for the target closing force, the holding motor is activated, whereby the not yet fully closed gripper is raised and thereby further closed. In this way, the effect of the dead weight of the gripper, with which the gripper acts on the bulk material during closing and filling, is reduced and influences a degree of filling of the gripper.

Furthermore, from EP 0 458 994 A1 a tension control for the tethers and closing ropes comprehensive gripper ropes of a bulk material handling device known. In order to avoid a jerk caused by loosening tethers when closing the gripper, the retaining pull is regulated accordingly. However, the control of the holding train is such that no reduced effect of the dead weight on the bulk material is achieved during the closing process, since the gripper is lifted only when it is fully closed. The tension control therefore does not influence the degree of filling of the gripper.

DD 244 962 A1 describes a method for crop picking control for automated gripper operation. Here, a gripper opening angle and a closing time of the remote on the bulk material gripper are monitored during the closing process of the gripper. If the gripper can not be closed during the closing process within a predetermined time to a predetermined extent, the closing process is interrupted and activates a lifting mechanism to lift the gripper from the bulk material. Subsequently, the closing process is restarted and checked whether it can be performed as specified. European patent specification EP 2 226 287 B1 discloses a method for filling a tether suspended gripper is known whose Greiferfüllvolumen is influenced by a holding torque of a holding device for the gripper is controlled so that during the closing operation, a gripping curve of the gripper is raised.

The invention is based on the object, a method for optimally filling a gripper for bulk material, which is raised and lowered by a crane via a control and which during closing and filling with his

Dead weight on the bulk material acts to create.

The object is achieved by a method for filling a gripper for bulk material with the features of claim 1. Advantageous embodiments of the invention and a use of the invention are specified in the subclaims. According to the invention is in a method for filling a gripper for bulk material, which is suspended from tethers, is raised and lowered by a crane via a controller and the closing and filling with his

Self-weight acts on the bulk material, wherein on the controller a degree of filling of the gripper is influenced by reducing the effect of the weight of the gripper on the bulk material by a force acting in the tethers tensile force is affected, an optimized degree of filling of the gripper achieved in that over Control for the tethers a traction setpoint value is determined, the traction setpoint value is output as an input to a tension regulator, the traction controller controls an electric motor for raising and lowering the gripper and the traction controller a determined traction ACTUAL value the tethers as

Input is supplied. As a result, overload shutdowns are avoided.

With this invention is advantageously achieved that the degree of filling of a bulk gripper can be controlled. It follows that when operating a crane with a bulk grapple an excessive number of

Overload shutdown is avoided and thus the handling capacity of the crane is increased. Such overload shutdowns occur when the gripper penetrates very deeply into the bulk material to be lifted during gripper operation and thus takes up too much bulk material in the gripper. This alone can already lead to an overload shutdown of the Cranes lead when the gripper receives more bulk than the crane can lift. Combined with a large boom radius, this effect is enhanced as the crane's approved payload decreases, making it even easier to overload, and in turn, overloading the crane. If the gripper is rather undersized with respect to the crane, such overload shutdowns of the crane can only occur with a large crane unloading. Since the handling capacity of the crane is always optimized in economic terms, a crane is operated more in the range of its authorized payload and thus with a gripper that can reach an optimal filling level over the entire discharge range. So in terms of the load capacity of the crane is rather slightly oversized or optimally dimensioned in terms of low discharges. This implies that an inserted gripper with respect to the crane tends to be overfilled and thus attack the method according to the invention, which aims at a specific reduction of the effect of the dead weight of the gripper. Also, it is possible to use in relation to load of the crane and the bulk density of the bulk material to be conveyed to large grippers, as they are only partially filled about the invention. The influence on the tensions acting in the tethers, which is made, in particular during the

Closing operation of the gripper to reduce the effect of the dead weight of the gripper on the bulk material, in this case takes place to such an extent that the gripper penetrates less far into the bulk material, as he alone through it

Dead weight would do.

In practice, the number of

Overload shutdowns are reduced by 90% and that at elevated

Handling capacity.

A load within the meaning of the invention consists of the weight of the gripper, recorded bulk material and in the case of a rope grab from the weight of the rope between boom tip and gripper together.

Advantageously, it is also provided that in the control of a tendency module on the basis of gradients of determined loads a time of change of the draft setpoint and a step size of a change in the draft setpoint value is supplied. By the integration of the tendency module can On the basis of stored empirical values - such as handling a comparable bulk material with the current gripper - and reached during the handling operation of the crane reached achieved filling levels faster optimal filling level can be achieved and safe overloads are avoided.

Here, the changes in the tensile load target value are dynamically adjusted during the closing process, so that an optimal utilization of the load curve in the entire radius range or discharge range is given and overloads are avoided or at least minimized. In an advantageous embodiment, it is provided that the tensile modulus is increased via the tendency module if the frequency of overload shutdowns exceeds a preselected value related to the load cycles and / or if the frequency of exceeding the maximum permissible load on the maximum allowable Load for a given radius exceeds the preselected value.

In an advantageous embodiment, it is provided that via the tendency module, the tensile force target value is lowered if the frequency of overload shutdowns falls below a preselected value related to the load cycles and / or if the frequency of exceeding the maximum permissible load on the maximum allowable Load for a given unloading preselected value falls below.

In a particularly advantageous embodiment, it is provided that is applied via the crane by means of the control of the gripper during closing and filling with the directed in one direction lifting tensile force value IST.

In order to avoid any overloading of the crane, it is provided that in the control of the degree of filling of the gripper from a determined immediately after lifting the filled gripper load and the known weight of the gripper is determined.

The determination of the degree of filling becomes more accurate in that the control is supplied via a rope length module as input to a length of a free rope from the gripper and in the lifting direction, in the control at the Calculation of the degree of filling of the gripper to the weight of the gripper and a weight of the free rope is added.

Usually, cranes for bulk handling from a tilting boom, so that changed during the turning and corresponding rocking of the boom, the radius of the crane. To take this into account, it is advantageously provided that the control via a load curve module as

Input quantity for the crane a maximum permissible load in response to a discharge of the gripper is supplied. Thus, the control has the maximum permissible load to determine overload cases and to determine the degree of filling of the gripper.

It is also advantageous that in the controller via a start value module as

Input variable manually a traction setpoint value is entered as start variable. In particular, after a gripper change or at the beginning of a new handling task with a bulk material with a different density can be entered based on experience, the starting size. As a result, the controller can achieve an optimal filling level of the gripper faster. In a preferred embodiment, the traction SOLL value is iteratively determined in the controller on the basis of the input variables from the load-load curve module, the

Rope length module and the determined load decreases or increases until the degree of filling of the gripper is in the range of 100%. Particularly advantageous is the use of the above-described method according to the invention for a crane with a gripper, which is raised, lowered, opened and closed via tethers and strikers.

The control underlying the method according to the invention is also considered to be inventive in its own right and their use is accompanied by the advantages described above for the method.

The invention will be explained in more detail with reference to an embodiment shown in a drawing. Show it: 1 shows a view of a harbor crane with a gripper for bulk material,

FIG. 2 shows a load-bearing curve of a harbor crane according to FIG. 1,

Figure 3 is an enlarged view of the gripper for bulk material of Figure 1 and

Figure 4 is a schematic representation of a controller for optimizing the degree of filling of the gripper for bulk material.

FIG. 1 shows a view of a mobile harbor crane 1 for the transshipment of

Bulk materials 14, such as ore, coal, grain, gravel or sand, between land and water or within cargo handling terminals. Of the

Mobile harbor crane 1 is equipped with a gripper 2 for handling bulk materials and consists essentially of a tubular base 3 and an upper carriage 4 with a tower 5 and a boom 6. The pedestal 3 is fixedly mounted on a floating pontoon 7. Instead of the pedestal 3 can also be

Undercarriage can be provided, which rests on a quay for the handling operation and is movable on the quay on rubber tires or on rails. On the pedestal base 3 of the superstructure 4 is rotatably mounted and pivotable about a non-illustrated rotary mechanism about a vertical axis of rotation d. The uppercarriage 4 also carries a hoist 8 in a rear region of the upper carriage 4, in which also a

Counterweight 9 is located. Also supported on the superstructure 4 of vertically extending tower 5, at the top of a roller head 10 is fixed with sheaves. Furthermore, the boom 5 is articulated to the tower 5 approximately in the region of its half length and on the side facing away from the counterweight 9. The boom 5 is pivotally connected to the tower 4 at one end about a horizontal rocking axis W. About a hinged to the boom 6 and the bottom of the upper carriage 4 luffing 1 1, which is usually designed as a hydraulic cylinder, the boom 6 is pivotable about a luffing angle w from its plurality of laterally projecting operating positions in an upright position of rest. In addition, the boom 6 is formed in a conventional manner as a lattice mast. At the tower 4 remote from the boom tip 6a of the boom 6 more sheaves are rotatably mounted on the basis of the hoist h on the roller head 10 and the boom tip 6a tethers 12 and closing cables 13 are guided to the gripper 2.

The rocking angle w is enclosed between a vertical V which passes through the rocking axis W and a straight line G which extends in the region of a top flange of the boom 6 and through the rocking axis W. In the usual way one goes Variation of the rocking angle w associated with a change in the radius a of the crane 1, which is related to the maximum load of the crane 1. The projection a corresponds to a horizontal distance between the vertical V through the rocking axis W and a likewise vertical cable direction S. The cable direction S coincides with the free and from the boom tip 6a running and stabilized holding and closing cables 12, 13 together. In addition, with the cable length I, a measure of freely suspended portion of the holding and closing cables 12, 13 between the boom syringe 6a and the gripper 2 is specified. In addition, it can be seen from FIG. 1 that a ship 15 loaded with bulk material 14, in particular a barge, a barge or a barge, can be loaded or unloaded by the crane 1.

FIG. 2 shows a so-called load-bearing curve of the port crane 1. The load-bearing curve shows the maximum permissible load of the crane 1 in tonnes above the projection a in meters. Here, roughly two load ranges I and II can be distinguished. In the first payload area I is due to the

Dimensioning of the crane 1 in the range of a radius of 0m to about 38m no decrease in the maximum authorized load of about 63t recorded. From a projection a of about 38 m to a maximum projection of about 51 m, the maximum permissible load decreases with increasing projection a. This area is defined as second payload area II. In connection with the

erfindungsmäßen control is the second payload range II in a first

Payload sub-area 111, second payload sub-area II2, third payload sub-area 113 and fourth payload sub-area II4 have been divided. Based on this load curve, an overload is defined as exceeding the maximum permissible load by approximately 10%.

In the figure 3 is an enlarged view of the gripper 2 for bulk material of Figure 1 is shown. The gripper 2 has two shells 2 a and is designed as a four-wire gripper, which is suspended from two tethers 12 and two closing cables 13. The holding and closing cables 12, 13 are independently from two within the hoist 8 arranged, separated from each other and separately driven by holding and closing winches rope drums up and unrolled to open the gripper 2, close, lift and lower , To open the slob 2, the Locking cables 13 relieved and the gripper 2 hangs only on the tethers 12. The tethers 12 engage a lever mechanism 16 of the gripper 2 and cause in conjunction with the weight of the gripper 2, an opening of the gripper 2. For a filling of the open gripper 2 with slack closing cable 13 placed over the tethers 12 on the bulk material 14. To the gripper 2 under the action of his

Dead weight to sink into the bulk material 14, then the tether 12 is released. By tightening the strikers 13 in the direction of lifting h the gripper 2 is closed. By closing the shells 2a of the gripper 2, this fills with the bulk material 14 and can also dig into the bulk material 14. When digging a serving as a slack rope regulator tension regulator 18 for the tethers 12, the component of a controller 17 (see Figure 4), only the tethers 12 held on train, so that the gripper 2 can sink into the bulk material 14 by its own weight , The tethers 12 are held only as long as train, as the closing cables 13 close the gripper 2. Also, the gripper 2 fills by the closing process with bulk material 14. Subsequently, after the closing of the gripper 2, this is lifted by the closing cables 13. Parallel then the

Ties 12 tightened to avoid slack rope. In the area of lifting of the gripper 2, the forces in the holding and closing cables 12, 13 are then adjusted to one another again via a corresponding control, so that the subsequent lifting takes place together with the holding and closing cables 12, 13.

If too much bulk material 14 is picked up during the gripping process, an excessively high total load with respect to the maximum permissible load can occur, taking into account the current projection a. This total load consists essentially of the weight of the absorbed bulk material 14, the weight of the gripper 2 and the weight of the free rope length I of the holding and closing cables 12, 13 together. If too high a total load is detected, a further lifting of the load is stopped via a load torque limiter 20 (see FIG. 4) in order to protect the crane. This total load can, for example, in the form of a load FLAST over

Strain gauges are determined on a cable drum of the hoist 8 and is the load torque limit 20 as an input variable available. In a crane database 21, this overload shutdown is logged. As described above, it can increasingly come to overload shutdown in crane operation when the load of the crane 1, bulk density, gripper volume and

Grapple's own weight are not matched. This is often the case when with respect to the bulk material to be transported 14 gripper 2 are used with too large gripper volume. In the operation of the crane 1 but the choice of the gripper 2 used is not always optimal. If in the gripping process so much bulk material 14 is received by the gripper 2 that the measured total load is below the maximum permissible load, a payload and the total load when opening the gripper 2 at the target position is logged in the crane database 21. The payload in terms of the weight of the

absorbed bulk material 14 is calculated from the total load under deduction of the dead weight of the gripper 2 and the weight of the free rope length I of the holding and closing cables 12, 13. Also in the crane database 21 a completed load cycle is recorded without overload.

FIG. 4 schematically shows a representation of a controller 17, in particular a programmable logic controller, for optimizing the degree of filling of the gripper 2 for bulk material 14, by means of which the function of the controller 17 will be explained in greater detail. With the help of the controller 17, the goal is achieved independently adjust a degree of filling of the gripper 2 with bulk material 14 as a function of the load capacity curve of the crane 1. Here, the degree of filling of the gripper 2 is optimally utilized without overloading the crane 1 in terms of its load capacity curve.

The controller 17 outputs as a control variable a tensile force target value Fsoll for the tethers 12, which serves as input to the tension regulator 18. On the basis of this tensile force desired value Fsoll, the tension regulator 18 controls an electric motor 19, which drives a cable drum (not shown) for the tethers 12. As a further input variable, the draft controller 18 is supplied with a tension actual value Fist which corresponds to a measured tensile force in the tethers 12. The tensile force actual value Fist is calculated from the current data of the electric motor 19, in particular of the

Motor current, determined.

As inputs, the controller 17, which is shown as an addition module and works, in addition to a crane database 21, a rope length module 22 a, a

Traglastkurvenmodul 22b, a start value module 22c and 22d tendency module 22d assigned. Within the cable length module 22a, the cable length I is determined, which is shortly before placing the gripper 2 on the bulk material 14 between the gripper. 2 and the boom tip 6a is present. This then the weight of the holding and closing cables 12, 13 can be determined. About the load curve module 22b receives the controller 17, data on the maximum allowable load (SWL, safe working load) as a function of the projection a. The projection a is determined in the usual way via the measured rocking angle w. The additional value used is the starting value module 22c, via which a starting variable for the draft setpoint Fsoll can be entered manually. This is helpful after a

Gripper change to get faster to an optimal filling of the drool 2. There is also still the tendency module 22d, in which tendencies are determined from ascertained workloads with respect to the maximum permissible load, which leads to an increase or a decrease in the draft setpoint value Fsoll. The

Trends can be adjusted on the basis of empirical values.

In particular, in the trend module 22d, the number of

Overload shutdowns determined that correspond to approximately a more than 1 10% utilization of the maximum permissible load.

The controller 17 depicts an iterative process in which the degree of filling of the gripper 2 adapts to the load-bearing curve. Starting with an overload switch-off due to a too high load in the gripper 2, the projection a and the load are stored. Upon renewed penetration of the gripper 2 in the bulk material 14 whose tethers 12 are loaded according to the projection a with a preselected amount to train to achieve a less deep penetration of the gripper 2 in the bulk material 14 due to its own weight. In this way, the gripper 2 takes less material and the crane 1 can be operated depending on the size of the preselected amount without overload shutdown. Since the penetration of the gripper into the material depends on various factors, a new calculation of the preselected amount takes place with each gripping process.

During the turnover operation, trends are formed in the controller 17 by means of the data recorded in the crane database 21 about the current turnover operation via the number of overload shutdowns and the number of load cycles. If these tendencies give rise to a frequency of overload trips that exceeds a preselected value relative to the load cycles, then

Control 17 of the draft setpoint Fsoll increased. These tendencies may be due to exceeding the maximum permissible load for the given radius a be so that an increase in the tensile load setpoint value Fsoll can already be done with one or more exceedances of the maximum allowable load within a predetermined number of load cycles, without that it has already come to overload shutdowns. Should this increase not be sufficient, since the frequency of overload trips or exceedances of the maximum permissible load, which have a preselected value relative to the

Load cycle exceeds, is still given, there is a further increase in the tensile load target value Fset. As a result, the traction setpoint Fsoll is thus incremented high until the frequency of overload trips or exceedances of the maximum allowable load no longer exceeds the preselected value relative to the load cycles.

If, during the handling operation, a frequency of overload shutdowns or of the trends formed in the controller 17 results

Exceeding exceedances that do not reach a preselected value in relation to the load cycles, in other words corresponding underruns, is reduced in the control of the draft setpoint value Fsetpoint. Should this reduction not be sufficient, since the frequency of overload shutdowns does not yet reach a preselected value in relation to the load cycles, then a further reduction in the draft setpoint value Fset occurs. As a result, the traction setpoint Fsoll is thus incremented down until the frequency of overload trips reaches the preselected value relative to the load cycles.

How high is the increase or decrease of the draft setpoint Fsoll in the controller 17 and how quickly respond to the trend change is parameterized in the controller 17. As a result, the controller 17 on the crane 1, the load capacity curve of the crane 1, the bulk density, the gripper volume and the

Adapted to grab weight. The traction setpoint Fsoll is also increased if the selected load curve is sufficiently utilized. This prevents the overload limits from being exceeded. This is done via a corresponding fuzzy logic in the

Control 17. This increase of the draft setpoint Fsoll serves in addition to bias the tethers 12 sufficiently at the end of the closing operation of the gripper 2, so that with almost closed gripper 2 the load on all four ropes 12, 13 is divided and thus no "dead time" when lifting the gripper 2 is formed.

In addition, there is an automatic adaptation of the tensile force desired values Fsoll to take into account the free cable length I of the holding and closing cables 12, 13. Die

Tension nominal values Fsoll are increased proportionally as a function of the rope length I with increasing rope length I and reduced as the rope length I decreases. This proportional adaptation of the tensile load values Fsoll leads to a

Compensation of the tensile forces, which comes about by the weight of the holding and closing cables 12, 13.

A further automatic adjustment of the tensile load setpoint values Fsoll occurs when the outreach is changed and thus a change in the maximum permissible load. The possibility is also provided for the crane operator to manually input a draft desired value Fsoll into the controller 17, which is then stored and used as a starting value for the controller 17. This manual value assists the crane operator when handling heavy loads by pre-controlling the traction setpoint Fsoll to a value without first determining the overload tendency or overshoot tendency.

With regard to the evaluation of the tendencies in the controller 17 which leads to a calculation of the draft setpoint value Fsoll, it is provided that this takes into account the load-bearing curve with the first payload area I, the first payload sub-area 111, the second payload sub-area II2, the third

Traglastunterbereich 113 and the fourth Traglastunterbereichs II4 done. In the first payload range I, the maximum permissible load is not dependent on the outreach. A correction of the tensile force desired value Fsoll is thus not carried out. The non-linear second payload area II is divided into the payload sub-areas 111, II2, 113 and II4. In the controller 17, the determined tendencies are assigned to the different load or sub-ranges I, 111, II2, 113 and II4. Thus, an optimal filling of the gripper 2 in response to the projection can be achieved faster. This is useful, for example, when the crane 1 changes between different ship hatches of a ship 15. The crane 1 thus always operates at the first load cycle with the maximum allowable load without unwanted Overload shutdowns.

In the controller 17, the individual increases or

Decreases of the draft setpoint Fsoll added together and transmitted to the draft regulator 18.

To the controller 17 to the crane 1, the load capacity curve of the crane 1, the

Bulk density, the gripper volume and the grab weight, the controller 17 can be parameterized with the following values:

- Number of load cycles until an increase of the tension setpoint is carried out (default = 1, 0) Example: If 1, 0 is specified, the setpoint is increased if an overload shutdown occurs.

- Value for the percentage increase of the tension setpoint (default = 5.0)

- Number of load cycles until a reduction of the tension setpoint is carried out (default = 2.0), Example: If 2.0 is specified, the tension setpoint is reduced, if a second load cycle with a fill level of less than 80% takes place.

- Value for the percentage reduction of the tension setpoint (default = 3.0) These values are displayed during commissioning of crane 1

Enter different grippers 2. Also, in the context of commissioning of the crane 1 for different grippers 2 or at least for the lightest gripper 2 respectively a basic tensile setpoint value is determined, which are manually entered as an initial value in the controller 17 when changing to a gripper. During commissioning, an optimization of the parameters takes place in order to quickly find an optimal one

To achieve filling behavior of the gripper 2. If, for example, very large and very heavy grippers are used, the tensile force SOLL value Fsoll in% of

Rated torque of the electric motor 19 adjusted so that the gripper 2 is no longer packed in the bulk material 14. The electric motor 19 then brings such a high

Torque on that the gripper weight is held.

After commissioning, it is checked whether the settings are proven in practice and adjusted if necessary. In the event that overload trips occur, after about 3 consecutive subsequent shutdowns the frequency of shutdown by changing the parameters or by manually setting the draft setpoint Fsoll be reduced. Within the controller 17 are the parameters that influence the

Change the tension setpoint value Fsoll have, adjustable. An adjustment is made during commissioning of the crane depending on the crane and the gripper used. Since the goal of the controller 17 according to the invention is an optimal filling of the gripper 2 with bulk material 14, each is optimized

Umschlagvorgang done at about 100% of the permissible load, ie in the vicinity of an overload, so that it still comes to overload shutdowns but with a significantly reduced frequency by the incremental increase and decrease of the draft setpoint Fsoll. As part of the turnover operation, 10% overload shutdowns per hour are considered to be non-interfering with respect to the load cycles and are regarded as a good control result within the scope of the present control 17. This means, for example, 50 to 60 load cycles per hour that 5 to 6 overload trips can continue to occur. Here is a

Overload shutdown also counted as a load cycle. Without the control 17 according to the invention, overload shutdowns can occur up to more than 50% of the load cycles per hour, in particular when the crane is used with respect to a heavy bulk material 14 with a gripper 2 that is too large in relation to the bulk material density.

Every overload cutoff causes a longer cycle time during operation, which has a negative effect on the handling capacity. By the controller 17 according to the invention, the gripper 2 is always quite full over time, even when working on different load hatches, since the gripper is always loaded automatically depending on the projection a and that without intervention of the crane operator.

Since the tensile forces acting in the tethers 12 are proportional to a torque applied to the cable drum for the tethers 12, applied by the electric motor 19, the invention described above comprises not only a determination and regulation of tensile forces, but also of corresponding moments. LIST OF REFERENCE NUMBERS

1 mobile harbor crane

2 grippers

2a bowl

3 pedestals

4 superstructures

5 tower

6 outriggers

6a jib tip

7 floating pontoon

8 hoist

9 counterweight

10 roll head

1 1 luffing mechanism

12 tethers

13 locking ropes

14 bulk goods

15 ship

16 lever mechanism

17 control

18 draft regulator

19 electric motor

20 load torque limit

21 crane database

22a rope length module

22b Load curve module

22c start value module

22d trend module

Throat

axis of rotation

Direction Lifting free rope length

Direction sinks Wippwinkel Fist traction-actual-value

FLast load

Fsoll traction target value

G straight

1 first payload area

II second load range

111 first payload subrange

II2 second load sub-area

II3 third payload sub-area

II4 fourth load sub-area

S rope direction

V vertical

W rocking axis

Claims

claims

1 . Method for filling a grab (2) for bulk material (14) which is suspended from tethers (12), lifted and lowered by a crane (1) via a control (17) and which during closing and filling with its

Self-weight on the bulk material (14) acts, wherein on the controller (17) a degree of filling of the gripper (2) by reducing the effect of the dead weight of the gripper (2) on the bulk material (14) is influenced by one in the tethers ( 12) acting tensile force, characterized in that on the control (17) for the tethers (12) a tensile force target value (Fsoll) is determined, the tensile force target value (Fsoll) as input to a tension controller ( 18) is output, from the tension regulator (18) an electric motor (19) for raising and lowering the gripper (2) is controlled and the tension controller (18) a determined tensile force value (Fist) of the tethers (12) as an input is supplied.

2. The method according to claim 1, characterized in that in the controller (17) via a tendency module (22d) on the basis of gradients of determined load a time of change of the tensile load target value (Fsoll) and a step size of a change in the tensile force -SOLL value (Fsoll) is supplied.

3. The method according to claim 2, characterized in that on the

Torsional modulus (22d) is increased when the frequency of overload trips exceeds a preselected value related to the load cycles and / or when the frequency of exceedances of the maximum allowable load exceeds the maximum allowable load for a given load Discharge (a) exceeds the preselected value.

4. The method according to claim 2 or 3, characterized in that via the tendency module (22d) of the tensile force target value (Fsoll) is lowered when the frequency of overload shutdowns falls below a preselected value related to the load cycles and / or if the frequency exceeding of the maximum permissible load exceeds a maximum permissible load for a given radius (a).

5. The method according to any one of claims 1 to 4, characterized in that over the crane (1) by means of the control (17) of the gripper (2) during closing and filling with the in one direction lifting (h) directed tensile force actual value (Fist) is applied.

6. The method according to any one of claims 1 to 5, characterized in that in the controller (17) the degree of filling of the gripper (2) from a determined after lifting the filled gripper load (TL) and the known weight of the gripper (2) is determined.

7. The method according to claim 6, characterized in that the controller (17) via a cable length module (22a) as input a length (I) of a free rope (12, 13) starting from the gripper (2) and in the direction lifting ( h) in the controller (17) in the calculation of the degree of filling of the gripper (2) the

Dead weight of the gripper (2) and a net weight of the free rope (12, 13) is attributed.

8. The method according to any one of claims 1 to 7, characterized in that the controller (17) via a load curve module (22b) as an input to the crane (1) a maximum allowable load in response to a discharge of the gripper (2) is supplied ,

9. The method according to any one of claims 1 to 8, characterized in that in the controller (17) via a start value module (22c) as an input manually

Traction set point (Fsoll) is entered as start size.

10. The method according to any one of claims 1 to 9, characterized in that in the controller (17) iteratively the tensile force SOLL value (Fsoll) on the basis of

Input variables from the load-load curve module (22b), the cable length module (22a) and the determined load (TL) is reduced or increased until the degree of filling of the gripper (2) is in the range of 100%.

1 1. Use of a method according to one of claims 1 to 10 for a crane (1) with a gripper (2), which is raised, lowered, opened and closed by tethers (12) and closing cables (13).