EP2674384B1 - Method for monitoring crane safety and crane - Google Patents

Description

The invention relates to a method for monitoring the crane safety of a crane and a crane with a variable support base.

It is known to monitor crane safety by means of a crane control during crane operation. The guarantee of crane safety is based on compliance with various safety criteria. The component strength of boom systems, hoisting ropes, load hooks, slewing rings, luffing cylinders, mechanical connections etc. on the one hand and the stability of the crane on the other hand are mentioned as possible safety criteria. Criteria related to the stability of the crane are, for example, tilting the crane in the load direction, tilting the crane in the counter-load direction, wind speed, the planned uppercarriage rotation angle, etc. For each of these criteria, permissible limit values can be determined, which are monitored separately for compliance to ensure crane safety during crane operation Need to become.

The monitoring process is carried out automatically by an implemented crane control, in particular the load torque limitation of the crane. Monitoring events can indicate and possibly lead to intervention in the crane movement.

During the manufacture and testing of the crane, so-called load-bearing tables are calculated in advance for all the criteria mentioned, the table entries of which define the maximum permissible load-bearing capacities for specific crane configurations.

As a rule, a crane is operated in a supported manner, the size of the support base being dependent on the extended state or the folded-out state of the sliding or folding bars of the supporting device. If a symmetrical support is impossible due to the location, the EP 0 779 238 B1 propose to reduce the entire support base to the smallest existing extension or unfolded state. The disadvantage of this procedure is that the actual load capacity that is actually present is lost in large parts of the upper carriage rotation angle. In addition, in this embodiment the position of the sliding or folding bars is limited to predetermined specific positions, since crane operation is only permitted for a limited number of support positions.

An alternative solution suggests that EP 0 779 238 B1 in front. This defines individual rotation angle ranges for the superstructure and specifies a uniform maximum load for each area. This specific maximum load corresponds in each case to the smallest load permissible in the individual areas. In this solution, too, the actual existing load is lost due to the jump between the rotation angle ranges.

From the DE 20 2006 017 730 U1 an alternative approach is known. The aforementioned safety criteria are no longer exclusively monitored using precalculated and stored load tables, but some of these criteria are also monitored individually against the values currently available on the crane. This achieves a certain diversity in crane monitoring, however, due to the use of individual load capacity tables, the maximum possible load capacity cannot be exhausted.

The DE 10 2005 035 460 A1 suggests taking individual support points for certain crane states from the existing load capacity tables and using interpolation to determine the current maximum load capacity based on these support values. Here, too, the certain permissible payload is subject to a certain inaccuracy, which may lead to a noticeable loss of the maximum payload.

It is common to the design variants known from the prior art that precalculated load capacity tables are always used. A variable crane configuration, in particular a variable support base, however, leads to an infinite number of possible crane configurations and corresponding load capacity tables. It is desirable to be able to make the crane configuration as flexible as possible, especially at the place of use.

Known cranes are operated in such a way that the parameters can be changed until the permissible load corresponds to or exceeds the actual load. The crane control is intended to prevent the crane from driving into an impermissible area and prevents further crane movements that would lead to the limit being exceeded. The permissible load is determined using the stored load tables. However, if one deviates from the usual practice with precalculated load capacity tables, these necessary fixed limit values are missing and no fixed action limits and warning limits can be defined.

If this limit is now exceeded during crane operation, possibly due to changing weather conditions, the crane is in the impermissible working area. In order to reduce the resulting dangers, the load torque limiter intervenes in the crane control, which can lead to the complete blockage of all crane movements.

So far, a so-called key switch was provided, which enabled crane movements with no or only partially active load torque limitation. This function was useful for making the crane ready for work or for moving out of a non-permissible working area, for example if the load torque limiter has stopped a crane movement.

If a key switch is no longer installed, crane movements can only be carried out if they are within the permissible load range. However, if the crane has been driven into an inadmissible area, the load torque limiter interrupts the current crane movement and blocks all further crane movements.

DE102005059768A1 discloses a method according to the preamble of claim 1 for operating a crane with a monitoring unit and a sensor system.

The object of the present invention is to further develop a method known from the prior art for overload protection on cranes.

This object is achieved by a method according to the features of claim 1. Further advantageous embodiments of the method are the subject of the following dependent claims.

According to claim 1, a method for operating a crane with a monitoring unit is proposed, the monitoring unit calculating a permissible load which is dependent on one or more changeable parameters during crane operation. The method according to the invention does not require any or no complete payload table. The calculation is carried out during crane operation on the crane, preferably according to the method according to one of Claims 5 to 12.

The current changeable parameter (s) are arbitrary. One or more parameters characterize, for example, the current crane configuration or executed crane movements or activities. The parameter can be a parameter relating to the position of the crane or a crane component.

At least one parameter can be the boom length, the boom angle, the direct ballast radius and / or the angle of rotation the turntable act. As stated, these are examples; of course, other parameters are also conceivable.

In addition, a sensor system is provided that records the current changeable parameters during crane operation and makes them available to the monitoring unit. According to the invention it is provided that one or more sensor values are modified before the calculation of the permissible load. In this way it is possible to determine the permissible load for one or more future parameters.

The method according to the invention consequently allows a predictive calculation of the possible permissible load for future crane movements. The crane's monitoring unit thus calculates in real time on the crane and at any time which permissible load capacities will occur in the near future if the current crane movements are continued. In addition, extensive prognoses can be made for the development of the future permissible load capacity depending on current and future crane activities. This procedure can be particularly necessary if there are no fixed limit values, i.e. load tables, for crane monitoring. The crane preferably always calculates, in parallel with the method according to one of claims 5 to 12, a forecast of how the permissible load will change if the current actual movement or currently possible crane movement is continued.

The method according to the invention does not require a comprehensive expansion of an existing crane or a monitoring unit. Rather, minor modifications are sufficient to adapt existing systems for carrying out the method. Means for manipulating the recorded sensor values only need to be provided.

It is particularly advantageous if the monitoring unit changes at least one parameter as a function of the calculated permissible load capacity during crane operation in order to control the permissible load capacity. For example, the speed of the parameter change can be reduced or stopped continuously or in steps, before a parameter value is reached at which the permissible one Load corresponds to the actual load. The monitoring unit reacts as soon as the payload changes towards zero. A pending crane movement can be slowed down or stopped in good time in order to avoid exceeding the permissible load. Alternatively or in addition, an output or display of a possible overshoot or an approach to a possible overshoot to the crane operator can take place.

Depending on the result of the forecast, the desired target movement of the crane is permitted, restricted or completely blocked. An essential feature here is the steepness of the change in the permissible load. This calculation is carried out using all relevant sensors.

The reduction can take place continuously or in stages. The speed can be reduced, for example, in such a way that it is gradually reduced to zero when or before the correspondence between the permissible and actual payload is reached, from a value that is lower than the other rate of change, or that the value zero is reached by continuously reducing the speed.

It can be provided that the speed of the parameter change from a difference between the actual and permissible payload, i.e. H. is reduced continuously or gradually over a certain remaining distance.

This difference can assume a constant value or a value that depends on the actual and / or permissible load or the difference thereof or the ratio of this difference to the actual and / or permissible load.

It is particularly advantageous if the parameter or parameters are changed in such a way that the actual payload cannot exceed the permissible payload.

According to the invention it is provided that at least one sensor value is checked by targeted modification, which Parameter change or parameter changes lead to a decrease in the actual load capacity and / or an increase in the permissible load capacity if the crane is already in an impermissible operating range, ie the current load capacity exceeds or corresponds to a permissible load capacity. The method shows preferred crane movements that enable particularly fast and safe driving out of the prohibited area.

According to the invention, any crane movement is stopped or limited as soon as the current payload exceeds or corresponds to the permissible payload. The crane operator is then given one or more possible parameter changes, i. H. Crane movements made available for selection in order to be able to safely and reliably move the crane out of the prohibited area.

It may be sufficient to indicate a possible parameter change to the crane operator. However, it is better to provide the operator with a selection of possible parameter changes.

In addition, it is expedient to only enable the parameter changes by the crane control which enable the safe and quick movement out of the non-permissible operating range. Other crane movements or parameter changes are limited or completely blocked.

The crane preferably comprises a variable support base. The support base is determined from the extended or unfolded state of the support device. The monitoring unit monitors several safety criteria during crane operation to ensure crane safety.

The individual safety criteria can relate, for example, to component strength, component loading and the stability of the crane. In particular, this includes tilting the crane in the load direction, tilting the crane in the counter-load direction, breaking the hoist rope, component strength of the boom system, wind speed, load limits of the undercarriage, strength of the load hook, slewing ring load, luffing cylinder strength, Strength of the mechanical connections as well as the intended angle of rotation of the superstructure with boom to be used during crane operation.

Specified calculation examples for the monitoring of individual criteria are, for example, the small test load, the large test load, load breakdown, tilt angle, tilting backwards without a load and a total of far more than 30 criteria. Individual criteria can be specified in the corresponding DIN standard, for example.

Provision is now preferably made for the monitoring unit to calculate a permissible specific limit value during crane operation for each criterion which is dependent on at least one parameter relating to the crane configuration and / or crane movement during crane operation. Accordingly, a load capacity table for corresponding criteria is not taken into account at all.

A criterion is dependent on at least one parameter relating to the crane configuration and / or crane movement during crane operation as soon as the actual crane configuration at the place of use or during crane operation has an influence on compliance with the criterion. In addition to the setup configuration, this also includes every crane movement that has an influence on a corresponding criterion. For example the current boom positions, the support base, the uppercarriage rotation angle, etc.

At least one specific limit value represents the permissible specific load capacity up to which a corresponding criterion is complied with and crane safety is not endangered.

The individual specific limit values or permissible specific load capacities can be monitored separately during crane operation and compared with the actual crane condition values. Alternatively or additionally, it can be advantageous to determine a common permissible load from the individual permissible specific limit values or loads. In this case a common maximum permissible load is determined for each crane condition or crane configuration.

By calculating the criteria on the crane, the maximum possible load capacity results in every situation, which results from the criteria for the current situation. This is the outstanding advantage compared to pre-calculated tables, which always represent a minimum over certain dimensions and can never fully utilize the crane's possible load capacity. According to the invention, the criteria that are no longer precalculated are calculated on the crane during runtime, that is, during crane operation. The execution of the method according to the invention now leads to a method or a monitoring device that can use any support base, d. H. allows any position of the support bars and is monitored at the same time. So far, any position was mechanically possible, but this was not safeguarded by the monitoring device for every case.

It can be useful that the individual criteria are divided into at least two different types of criteria for the calculation of the joint permissible load. For example, the individual criteria are divided into linearly dependent and linearly independent types of criteria. Linearly dependent preferably means that such a criterion depends on at least one further criterion. In particular, at least one linearly dependent criterion can be dependent on at least one calculated specific limit value / load capacity of at least one further linearly dependent and / or linearly independent criterion.

A particularly advantageous embodiment of the method results from the fact that in a first step the permissible specific load is calculated for each linearly independent criterion. From the amount of specific loads for the linearly independent criteria, the minimum of these loads is then determined. The permissible load of the linearly dependent criteria is determined by iteration. It is conceivable that the iteration with the minimum of the permissible Loads of the linearly independent criteria begins and a minimum of the loads of the linearly dependent criteria is determined, which at the same time corresponds to the common permissible load for the crane.

To accelerate the method for determining the permissible load, it is possible, for example, to rely on the section, in particular continued bisection. This can reduce the calculation time for determining the permissible load.

It is possible, in addition to the method according to the invention, to store one or more load tables in a storage unit of the crane and to take them into account for monitoring the crane. The stored load capacity tables are, however, exclusively those which are not dependent on a parameter relating to the crane configuration and / or crane movement during crane operation. When creating the load capacity tables, all criteria that are dependent on at least one parameter relating to the crane configuration during crane operation are excluded. Consequently, mainly strength-relevant load capacity restrictions are stored on the crane as precalculated load capacity tables. These contain limit values, compliance with which avoids lasting damage to the crane through mechanical overload, for example through load acceptance.

In addition, it can be provided that an integrated crane operation planner is used for diverse crane monitoring during crane operation. The crane planner preferably uses stored limit curves or envelope curves for at least some of the crane parameters. Accordingly, there are two independent crane monitoring methods, on the one hand to ensure the redundancy of the monitoring and on the other hand to check the functionality of the overall system in each case by the two monitoring methods provided independently of one another checking the functionality of the other monitoring method. In this context, the DE 10 2008 021 627 taken.

The invention also relates to a crane with a monitoring unit and a sensor system. According to the invention, the crane carries out the above-described method according to the invention or an advantageous embodiment of the method according to the invention. The advantages and properties of the crane obviously correspond to those of the method according to the invention, which is why a renewed description is dispensed with at this point.

The invention also relates to a crane monitoring unit, in particular a load torque limiter, for the aforementioned crane for carrying out the method according to the invention or an advantageous embodiment of the Procedure.

Another aspect of the invention relates to a data carrier with stored software for execution on the aforementioned crane monitoring unit, comprising commands that cause the aforementioned crane to carry out the method steps according to the invention. The advantages and properties of the crane monitoring unit or the data carrier obviously correspond to those of the method according to the invention, which is why a repetitive description is dispensed with here too.

Figuren 1 bis 4:

eine graphische Darstellung der Traglastverteilung in Abhängigkeit des Oberwagendrehwinkels bzw. der maximalen Ausladung, berechnet nach einem Verfahren gemäß Stand der Technik,

Figuren 5 bis 8:

eine graphische Darstellung der Traglastverteilung in Abhängigkeit des Oberwagendrehwinkels sowie der maximalen Ausladung, berechnet nach dem erfindungsgemäßen Verfahren,

Figur 9:

eine schematische Darstellung der erfindungsgemäßen Überwachungseinheit und

Figur 10:

ein Flussdiagramm des erfindungsgemäßen Verfahrensablaufs.

Further advantages and properties of the invention are explained in more detail with reference to drawings. Show it:

Figures 1 to 4:

a graphic representation of the load distribution as a function of the uppercarriage rotation angle or the maximum radius, calculated according to a method according to the state of the art,

Figures 5 to 8:

a graphic representation of the load distribution as a function of the uppercarriage rotation angle and the maximum radius, calculated according to the method according to the invention,

Figure 9:

a schematic representation of the monitoring unit according to the invention and

Figure 10:

a flow chart of the method sequence according to the invention.

The Figures 1 to 8 show the distribution of the permissible load capacity of a crane as a function of its radius or the slewing angle of the superstructure. The crane sketched in the center comprises an undercarriage, an uppercarriage rotatably mounted on the undercarriage and a variable support. The variable support comprises a total of four sliding bars that can be extended into different support positions. In addition, a luffing crane boom that can be telescoped is arranged on the superstructure can be designed. During crane operation, the current load depends on the rotation angle of the superstructure and the load radius, ie the luffing angle of the boom.

A monitoring device on the crane monitors compliance with the permissible load capacity during crane operation. In particular, any desired position of the support bars is not only permitted by the method according to the invention but also monitored by the monitoring device at the same time.

• Kleine Prüflast gemäß DIN 15019 Teil 2
• Große Prüflast gemäß DIN 15019 Teil 2
• Lastabriss gemäß DIN 15019 Teil 2
• Kippwinkel gemäß DE 13000 Anhang F
• Kippen nach hinten ohne Last gemäß BS 1757 und ISO 43053.3.2

The crane or the monitoring device has access to a few load capacity tables that contain load capacity restrictions of the crane that are relevant to the strength of the crane. These should, for example, prevent permanent damage to the crane due to mechanical overload. For safety criteria that depend on one or more operating parameters of the crane, the calculation of the permissible load during runtime on the crane is carried out by the monitoring device, ie during crane operation. Among other things, the following criteria are calculated:

• Small test load according to DIN 15019 part 2
• Large test load according to DIN 15019 part 2
• Load break in accordance with DIN 15019 part 2
• Tilt angle according to DE 13000 Appendix F.
• Tilting backwards without load according to BS 1757 and ISO 43053.3.2

In addition, a total of more than 30 criteria can be calculated. Calculating the criteria on the crane allows the maximum possible load to be exhausted in every situation and not having to take into account interpolation or estimation-related inaccuracies, which for safety reasons always require a conservatively determined permissible load.

wobei die Kipplast die Last bei der der Kran kippt darstellt und das Auslegerkopfgewicht durch einen definierten Gewichtsanteil am Ausleger definiert ist. Für die linear abhängige Berechnungsart kann beispielsweise das Kriterium der kleinen Prüflast herangezogen werden, die sich nach der Formel: $$\mathit{TL}=\frac{\mathit{Kipplast}-\mathit{Hdyn}-W\left(\mathit{TL}\right)}{\mathrm{1,1}}$$

berechnet. Auch hier stellt die Kipplast die Last bei der der Kran kippt dar. Hdyn charakterisiert den dynamischen Hublastbeiwert. W führt den Windeinfluss in die Berechnung ein, der unter Berücksichtigung der Traglast berechnet wird. Die kleine Prüflast ist demnach von der berechneten Traglast wenigstens eines Kriteriums abhängig, was als linear abhängig bezeichnet wird. Denkbar ist es ebenfalls, dass die Berechnung rekursiv ist. Für die Berechnung des Windeinflusses werden beispielsweise 1,2 m² Windangriffsfläche pro 1 t Traglast angenommen.To calculate the permissible load, the criteria are divided into different, ie at least two different types of calculation. For example A linearly independent calculation type applies to the calculation of the large test load. The large test load is calculated using the following formula $$\mathit{TL}=\frac{\mathit{Tipping\; load}-0.1\ast \mathit{Boom\; head\; weight}}{1.25},$$

where the tipping load represents the load at which the crane tilts and the jib head weight is defined by a defined weight proportion on the jib. For the linearly dependent calculation type, for example, the criterion of the small test load can be used, which is based on the formula: $$\mathit{TL}=\frac{\mathit{Tipping\; load}-\mathit{Hdyn}-\mathrm{W.}\left(\mathit{TL}\right)}{1.1}$$

calculated. Here, too, the tipping load represents the load at which the crane tilts. Hdyn characterizes the dynamic lifting load coefficient. W introduces the wind influence into the calculation, which is calculated taking the load into account. The small test load is therefore dependent on the calculated load capacity of at least one criterion, which is referred to as linearly dependent. It is also conceivable that the calculation is recursive. For the calculation of the wind influence, for example, 1.2 m ^{2 of} wind attack area per 1 t of load is assumed.

The algorithm for the calculation divides the criteria into linearly dependent and linearly independent criteria. In the first step, the permissible load is determined for each linearly independent criterion. Then the minimum of these TL _{criteriaA of} these payloads is determined and recorded.

In a second method step, an iteration of the permissible load capacity is carried out with the previously determined minimum TL _CriteriaA as the starting value. In the iteration, the linearly dependent criterion is checked for admissibility in each step. If the criterion is admissible, the next criterion is used. As soon as a criterion is no longer permissible, the next iteration step in jumped to the relevant criterion without carrying out a further check of the other criteria.

The second step is started again with this new load TL. This continues until the second step provides a permissible load TL _CriteriaB for all criteria. This becomes the permissible maximum load TL. After the n-iteration steps have been carried out, the method according to the invention is intended to provide the largest possible value for the permissible load TL. The determination of the load TL can also be carried out with the help of the continued bisection.

The advantages of the invention should be based on the representations of Figures 5 to 8 as well as the load capacity representations according to the state of the art ( Figures 1 to 4 ) are explained.

The scale on the right edge of the image assigns the corresponding load values to the gray values. The crane configurations of the Figures 1 and 5 , 2 and 6 , 3 and 7th such as 4th and 8th are identical in each case and are used for comparison.

In all figures, three telescopic sections of the boom system are 46% extended. The sliding bars of the support are in the crane configuration according to Figures 1 and 5 fully extended and allow a maximum support base. The configuration of the Figures 2 and 6 provides, on the other hand, to operate the crane without support and to leave the sliding bars fully retracted. The crane according to the Figures 3 and 7th works with limited support, whereby two sliding bars on one side of the crane are fully extended and the opposite bars are fully retracted. The crane configuration of the Figures 4 and 8th provides a crane operation with three fully extended and one retracted sliding beam.

The representation of the permissible load in the Figures 5 to 8 is based on a calculation during crane operation on the basis of the method according to the invention, whereas the illustration of Figures 1 to 4 on the use of load capacity tables that were created with the help of an operational planner prior to crane operation.

Especially the comparison of the Figures 2 and 6 shows the essential gain in load capacity that can be achieved with the aid of the method according to the invention. The method from the prior art assumes a minimal support base for the entire scope of the angle of rotation, whereas the method according to the invention calculates this exactly during crane operation and thus arrives at different permissible loads over the angle of rotation range. In particular, no permissible load is given away on the front and rear of the crane, since the missing support device is compensated for by the longitudinal dimension of the crane in this rotational angle range and is therefore higher than in the side area of the crane.

Not only the outer contour of the load curve is interesting, but also the inner contour, ie the white field around the axis of rotation of the superstructure. This area shows the inadmissible area, as the crane ballast can tip over backwards here. In this case too, according to Figure 6 this inadmissible area clearly compared to the area Figure 2 be reduced.

The gain in permissible load due to the optimized calculation is also used in the remaining Figures 5 , 7th and 8th clear. Here, too, the outer contour clearly shows the gain in payload. In the area in which the boom is located above one of the sliding bars, ie on the diagonal of the crane, a significant increase in the load capacity can also be recorded.

In Figure 5 the darker area with the higher load almost forms a square with concave sides. The permissible load capacity is made particularly along the diagonal compared to the variant Figure 1 elevated.

The comparisons of the Figures 3 and 7th as well as 4 and 8. Here the change can be explained by the fact that with a calculation according to the state of the art, the minimum in the area of 360 ° rotation range of the superstructure is assumed to be the maximum load for the entire slewing range of the superstructure. The invention breaks away from this way of thinking and can determine the load capacity individually for each rotational angle position of the superstructure.

The illustrated system of Figure 9 shows a load moment limiter 20 which monitors all crane movements with regard to their safety during crane operation and, if necessary, triggers a safety shutdown or restriction of the permissible crane movement. This system can according to the embodiment described above Figures 5 to 8 be carried out and carry out the presented method according to the invention. The following method represents an extension of this method. However, this is not a mandatory requirement for the execution of the following method steps, which are independent of the method according to the Figures 5 to 8 are executable.

The load torque limiter 20 receives measured values from a large number of sensors 10 during crane operation, which values characterize individual parameters during crane operation. It should be noted that Figure 9 shows a number of three sensors merely by way of example. In a realistic environment, however, the system is based on a large number of sensors, the number of which is not limited.

The individual measured values of the sensors 10 characterize, for example, the angle of rotation, luffing angle or also cylinder pressure of the luffing cylinder of the crane; On the basis of the provided sensor data, the load moment limiter calculates the permissible load for the current crane condition.

In order to be able to guarantee safety during crane operation, it should only be operated in the permissible working area. The permissible range is characterized by the fact that the current load capacity of the crane is lower than the permissible load capacity in the current operating state. If the current load exceeds the permissible value, the crane is working in the non-permissible range.

The aim of the method according to the invention is to ensure that the load torque limitation triggers an early braking of the crane movement before entering a non-permissible work area. In addition, a restricted crane movement in the non-permissible range is to be made possible under certain circumstances and the safety of the crane is nevertheless to be monitored by means of the load moment limitation.

For this purpose, the sensor values 11, 12, 13 for the calculation of the forecast of the permissible payload are specifically changed in suitably selected steps. In the illustrated embodiment of Figure 9 the sensor value 11 of the sensor 1 is manipulated in order to be able to calculate the permissible load for this future parameter, ie the future actual value of the sensor 1. The load moment limiter 20 calculates the permissibility of the crane movement for the changed sensor values and can therefore estimate when the crane will be steered into a non-permissible range while maintaining the current crane movement.

Each existing system of sensors 10 and load torque limiter 20 can be expanded by integrating the means 50 in order to be able to carry out a targeted manipulation of at least one sensor value 11.

The load moment limiter 20 thus calculates in real time on the crane and at any time which permissible loads will occur in the near future if the current crane movement is continued. With the help of the forecast development of the payload, the load torque limiter can recognize at an early stage whether the permissible payload converges to the value zero. In this case, the crane movement can be slowed down or stopped completely in good time. It is also possible to issue a corresponding warning to the crane operator.

In addition, the method according to the invention enables a restricted crane movement in the non-permissible range, which simultaneously from the load torque limiter 20 is monitored. It should be noted here that the load torque limiter 20 has the task of stopping a crane movement well before actual malfunctions or an accident occur. Operation in the non-permissible range does not mean an acute dangerous situation, but merely the exceeding of a specially defined limit value.

The flow chart of the Figure 10 shows the method according to the invention for checking permissible crane movements in the non-permissible range. The state 200 characterizes the regular crane operation, the crane movement is carried out unhindered in method step 110 and continuously monitored by the load torque limiter 20 in block 120 for compliance with the permissible load.

Due to the predictive calculation of the permissible load capacity according to the invention, the crane movement can be slowed down or stopped completely in good time. If such an emergency stop has taken place, the load torque limiter 20 goes to method step 200. Here, from the calculated forecast, it is determined with which crane movements or movements the crane can safely be driven out of the non-permissible area again. A possible selection is also displayed to the operator. The crane operator can therefore choose the most favorable variant depending on the situation. In step 300, the release of the selected crane movement is checked. This ensures that only the crane movements released by the load torque limiter and displayed in step 200 are carried out and other crane movements are blocked.

If the operator selects an enabled movement, this is carried out 400 and continuously monitored 500 by the load torque limiter.If the crane movement does not lead to the desired result, i.e. to leave the impermissible range, a safety stop is triggered again by the load torque limiter. Only after leaving the impermissible working range does the load torque limiter switch to the regular state 100 and enable all crane movements.

Claims (16)

1. A method of operating a crane having a monitoring unit that calculates an admissible bearing load dependent on one or more modifiable parameters during crane operation and having a sensor system which detects the current modifiable parameters during crane operation and makes them available to the monitoring unit, characterized in that one or more sensor values (11, 12, 13) are modified before the calculation of the admissible bearing load to determine the admissible bearing load for one or more future parameters; and in that verification is carried out as soon as the bearing load corresponds to the admissible bearing load or exceeds it and the monitoring unit has stopped or limited the crane movement, with a check being made in the verification by a targeted modification of the at least one sensor value as to which parameter modification or parameter modifications leads/lead to a decrease of the actual bearing load and/or an increase of the admissible bearing load and at least one or more parameter modifications or crane movements are displayed and/or released.
2. A method in accordance with claim 1, characterized in that the monitoring unit modifies the parameter or parameters so that the actual bearing load cannot exceed the calculated admissible bearing load, with the modification of at least one of the parameters preferably being carried out in a manner such that the rate of the parameter modification is decreased continuously or stepwise or stopped before a parameter value at which the admissible bearing load corresponds to the actual bearing load is reached.
3. A method in accordance with one of the preceding claims, characterized in that the at least one parameter is a parameter relating to the position of the crane or of a crane component and/or at least one further parameter is a parameter relating to the jib length, the jib angle, the derrick ballast radius, and/or the rotation angle of the slewing ring.
4. A method in accordance with one of the preceding claims, characterized in that the rate of the parameter modification is decreased continuously or stepwise from the falling below of a difference between the actual bearing load and the admissible bearing load.
5. A method in accordance with one of the preceding claims, characterized in that the crane comprises a modifiable support base and the monitoring unit monitors a plurality of safety criteria during crane operation to monitor the crane safety in that an admissible specific limit value is calculated during crane operation for each criterion which is dependent on at least one parameter relating to the crane configuration and/or the crane movement and is monitored for compliance.
6. A method in accordance with claim 5, characterized in that the at least one parameter relating to the crane configuration and/or crane movement during crane operation relates to the modifiable support base and/or the upper carriage rotation angle.
7. A method in accordance with one of the preceding claims 5 or 6, characterized in that at least one specific limit value is the admissible specific bearing load.
8. A method in accordance with one of the preceding claims 5 to 7, characterized in that the admissible total bearing load is calculated from the individual specific limit values or admissible specific bearing loads of the individual criteria.
9. A method in accordance with claim 8, characterized in that the criteria are subdivided into at least two different calculation types, in particular into linearly dependent and linearly independent calculation types, for the calculation of the admissible total bearing load.
10. A method in accordance with claim 9, characterized in that in a first step the admissible bearing load is calculated for every linearly independent criterion and subsequently the minimum of these bearing loads is determined and in a second step an admissible bearing load for the linearly dependent criteria is determined by means of iteration, with the iteration preferably starting with the minimum of the bearing load of the linearly independent criteria.
11. A method in accordance with claim 10, characterized in that the determination of the bearing load occurs by means of continued bisection.
12. A method in accordance with one of the preceding claims 8 to 11, characterized in that one or more previously calculated bearing load charts are stored on the crane in a retrievable manner, with the charts containing strength-relevant limit values.
13. A method in accordance with one of the preceding claims, characterized in that an integrated crane deployment sensor is used for a diverse crane monitoring.
14. A crane having a monitoring unit, a sensor system, and preferably a modifiable support base for the carrying out of the method in accordance with one of the claims 1 to 13.
15. A crane monitoring unit, in particular a load torque limitation for a crane in accordance with claim 14, for carrying out the method in accordance with one of the claims 1 to 13.
16. A data carrier having stored software for execution on a crane monitoring unit in accordance with claim 15 comprising commands that have the effect that the crane in accordance with claim 14 carries out the method steps in accordance with one of the claims 1 to 13.

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