EP1748021B2 - Method for measuring loads for cranes - Google Patents

Description

The invention relates to a method for determining the permissible load capacity of a crane.

So far, the permissible load capacity of a crane has been determined for certain set-up or condition parameters that have to be specified explicitly. For example, load specifications are known for certain, specified revolving platform ballast levels of e.g. 10 t and 20 t or for certain boom lengths and projections. The same applies to other parameters that have an influence on the permissible load capacity of a crane. The permissible values of the payload are often given in the form of payload tables, whereby the values of the payload are usually given in relation to two parameters. A disadvantage of this procedure is that it is not possible to determine the payload for any parameter values that can be freely selected within a parameter range, which results in the disadvantage that the payload determination is relatively imprecise.

In the DE 199 33 917 describes a method for setting a safety working range and a rated load in accordance with a working condition of the machine. According to this method, from a rated load based on the strength, which is set in consideration of the working radius and the strength of the pivot member and which is constant regardless of the pivot angle of the pivot member, and a rated load on the Based on the stability, which is set in consideration of the stability of the working machine and which changes depending on the swivel angle of the swivel element, the lower value is picked up for each swivel angle and set as a nominal load to be actually used, which is output by a nominal load data output device.

In the EP 1 153 876 describes a method for overload protection of a mobile crane, in which component-related geometric data are stored in a memory. According to a selected setup state, the geometry data are compiled in a simulation computer to form a physical simulation model. Taking real measurement data into account, the required geometrical data, center of gravity data and forces and, from this, the shutdown values are calculated.

From the DE 26 35 974 A1 a method having the features from the preamble of claim 1 is known.

It is therefore the object of the invention to develop a method of the type mentioned at the beginning in such a way that the permissible load capacity of a crane can be determined for any parameter values.

This object is achieved by a method with the features of claim 1. It is then provided that the load capacity is determined as a function of the crane's radius and the main boom angle of the crane, and that the method includes a first step in which the load capacities for the crane's radius at different values of the crane's main boom angle are determined by interpolation or extrapolation on the basis of known values of the lifting capacity at certain values of the radius of the crane, and in that the method comprises a second step in which the lifting capacity for the value of the main boom angle of the crane on the basis of the in the first step for different values of the main boom angle of the crane is carried out by interpolation or extrapolation, whereby the specific values of the crane radius, for which the values of the lifting capacity are known, are selected as a function of the values of the main boom angle of the crane.

In an example not belonging to the invention, the load capacity is to be determined, for example, as a function of the parameters radius (21.7 m) and main boom angle (83 °). The following procedure can be used: The permissible load capacity is determined, for example, by interpolating the load capacity for a first and second angle (77 °; 87 °) of the main boom using two support points from load capacity values that are known for the different projections are. It is conceivable, for example, to interpolate for a radius of 21.7 m between the support points 20 m and 22 m where the load capacity is known. This interpolation is carried out for a boom angle of 77 ° and for a boom angle of 87 °. If the load capacity is then to be determined for a boom angle of 83 °, then in a second step an interpolation is carried out between the load values obtained for the boom angle 77 ° and for the boom angle 87 °, ie the second interpolation step works according to this example with the support points that were obtained in the first step.

According to the invention, the specific values of the outreach of the crane, for which the values of the load capacity are known, are selected as a function of the values of the main boom angle of the crane. In relation to the previous example, this means that the support points for interpolation or extrapolation of the load capacity are selected depending on the angle of the main boom, in contrast to the previous example, in which identical support points were used for both main boom angles. According to the invention, with a larger main boom angle, i.e. with a steeper inclined main boom, smaller values of the radius are selected as support points than with a smaller main boom angle. For example, it is conceivable to choose the support points with a main boom angle of 77 ° at 20 m and 22 m and with a main boom angle of 87 ° at 14 m and 16 m. Of course, these are only exemplary values.

The procedure for selecting the specific values of the crane radius, for which the values of the load capacity are known, depending on the values of the main boom angle of the crane, is of course not only applicable to the parameters radius and main boom angle, but also for other parameters, in particular applicable to parameters that are dependent on each other.

The interpolation or extrapolation can be carried out assuming a linear relationship or also on the basis of any other functions that reflect a dependency of the payload on the respective parameter.

The method according to the invention is not restricted to two independent parameters. Rather, any number of parameters that have an influence on the load-bearing capacity can be taken into account. It can thus be provided that the The payload is to be determined as a function of n parameters, where n ≥ 2 and wherein the method comprises an n-th step in which the payload is determined on the basis of the in the (n-1) -th step for different values of the n- The values of the payload determined by the th parameter are carried out by interpolation or extrapolation. This means that the nth step in determining the load capacity works with support points that were determined in the previous, ie (n-1) th step.

The method can be implemented with a small number of support points. In principle, it is sufficient if the interpolation or the extrapolation is carried out on the basis of two interpolation points.

It can also be provided that the parameters are entered by hand. As an alternative or in addition to this, the parameters on the crane can be determined by a sensor. In both cases, a stepless setting or acquisition of the parameters is preferably possible. The acquisition of a parameter by means of a sensor is particularly useful if the value has a fixed size (e.g. ballast plate identification) or can be rounded to a fixed size (discretization). The acquisition of parameters by means of a sensor comes into consideration, for example, with the parameters revolving platform ballast and / or central ballast. Of course, other parameters, such as the wind speed, can also be detected by means of a sensor.

The parameters that are included in the calculation of the load capacity are preferably set-up or condition parameters of the crane.

Parameters in addition to the outreach of the crane or the main boom angle of the crane, which have an influence on the load capacity, can be selected from the following non-exhaustive group: turntable ballast, central ballast (undercarriage additional weight), support geometry, wind speed, longitudinal and lateral inclination of the crane, travel speed ( for tables on tires or caterpillars), derrick radius, derrick ballast, angle of rotation of the turntable, longitudinal and transverse angles of the jib guy stand (TA, TY). With regard to the support geometry, "retracted", "reduced", "wide", 10% steps or finer steps of the sliding beam length can be set instead of fixed, predetermined steps.

If the variable detected by means of a sensor fluctuates strongly, as can be the case, for example, with the wind speed, or changes without the influence of the crane driver, such as the lateral inclination, the sensor value can be used to make the load capacity calculation, preferably permanently, when a parameter limit is exceeded for the first time to switch so that a different, possibly a lower parameter value is taken into account for the measured sensor value. In this way it is possible to determine a small and therefore safer payload in operation.

Further details of the invention are explained in more detail using an exemplary embodiment described below.

The load calculation is carried out for any freely selectable values of a parameter within a parameter range. The value of the parameter can, for example, be typed in using a number keypad on a monitor. Alternatively, it is conceivable to select the parameter value from a series of arbitrarily finely graduated, predetermined values by selection or with a "<" or ">" key and pressing an Enter key.

In a first example not belonging to the invention, the parameter values for a derrick crane with luffing jib without derrick ballast are a main boom angle of 83 ° and an outreach of 21.7 m. The dependence of the permissible load on the outreach for the main boom angles 77 ° and 87 is known °. In a first step, the load capacity value for the radius of 21.7 m is determined by interpolation between the known support points at 20 m and at 22 m, both at the main boom angle of 77 ° and at the main boom angle of 87 °. In a second step, the load capacity values obtained for both main boom angles 77 ° and 87 ° are interpolated Load value determined for the main boom angle 83 °. There are thus two interpolations of the payload depending on the radius and one interpolation of the payload depending on the main boom angle.

According to the invention, the support points of the overhang are selected differently for the different main boom angles.

In a second example not belonging to the invention, the parameter values for a derrick crane without luffing jib with derrick ballast are a derrick ballast radius of 14.5 m and an outreach of 21.7 m.The dependence of the permissible load capacity on the outreach for the derrick ballast radii 13 m is known and 15 m. In a first step, the load capacity value for the radius of 21.7 m is determined by interpolation between the known support points at 20 m and at 22 m, both for the derrick ballast radius of 13 m and for the derrick ballast radius of 15 m In a second step, by interpolating the load values obtained for both derrick ballast radii 13 m and 15 m, the load value for the derrick ballast radius 14.5 m is also determined by interpolation.

The method according to the invention is not limited to the determination of the payload as a function of two parameters. There is no limit to the number of parameters. In one example, let the parameter values for a derrick crane with luffing jib and derrick ballast be a radius of 21.7 m, a derrick ballast radius of 14.5 m and a main boom angle of 83 °.

It is known that the permissible load capacity depends on the radius for the derrick ballast radii 13 m and 15 m, specifically for the main boom angles of 77 ° and 87 °.

According to an exemplary embodiment which does not show all the features of the invention, the load capacity value for the radius of 21.7 m is determined in a first step by interpolation between the known support points at 20 m and at 22 m both with the derrick ballast radius of 13 m and with the derrick ballast radius 15 m and this separately for both main boom angles. According to the invention, the support points for the projection are selected differently for different main boom angles. In total, four interpolations of the load are carried out in the first step depending on the radius. The values determined for derrick ballast radius values of 13 m and 15 m are interpolated with respect to the value 14.5 m. This interpolation takes place for both main boom angles (77 ° and 87 °). There are thus two interpolations of the payload for different derrick ballast radius values. The result of these interpolations are two payload values for the main boom angles 77 ° and 87 °. Finally, an interpolation takes place on the basis of these support points for the main boom angle 83 °.

An example not covered by the invention can be given for the parameters radius, derrick ballast radius and derrick ballast (e.g. 255 t). In this case there are again four interpolations over the radius, two interpolations over the derrick ballast radius and one interpolation over the derrick ballast (support points e.g. at 200 t and 300 t).

In the example given below, which is not covered by the invention, the payload is to be determined as a function of four parameters. These are the parameters outreach (21.7 m), main boom angle (83 °), derrick ballast radius (14.5 m) and derrick ballast (255 t). The load capacities are known depending on the radius for two different derrick ballast radii, namely with the parameter values derrick ballast 200 t and 300 t and with the main boom angles 77 ° and 87 °.

First of all, the load capacity for the radius of 21.7 m and for derrick ballast radii of 13 m and 15 m is determined between the support points of the 20 m and 22 m radius. This determination is made for the four pairs of values of the derrick ballast and the main boom angle 300t, 77 °; 300 t, 87 °; 200 t, 77 ° and 200t, 87 °. In total there are eight interpolations of the load capacity depending on the radius carried out at two support points each. On the basis of two of the load values determined in this way, four interpolations are carried out for the derrick ballast radius value of 13.7 m.

The load values determined for the four aforementioned pairs of values are fed to further interpolation steps, two interpolations being carried out for different main boom angles and the same derrick ballast radii in each case. The result of this interpolation consists of two load values for different derrick ballast values.

The last interpolation is carried out with a view to determining the load value for different derrick ballast values at 200 t and 300 t in order to obtain the permissible load value for a derrick ballast of 255 t in this way.

According to the invention, the support points for the projection are selected differently depending on the main boom angle.

Claims (8)

1. Method for determining the permitted payload of a crane in which the payload is to be determined in dependence on n parameters, wherein n ≥ 2 and wherein the parameters include at least one first and one second parameter, wherein the method comprises
   a first step in which the payloads for the value of the first parameter are determined by calculation or by interpolation or extrapolation at different values of the second parameter on the basis of known values of the payload at specific values of the first parameter, and
   a second step in which the payload for the value of the second parameter is carried out by calculation, or by interpolation or extrapolation on the basis of the values of the payload determined in the first step for different values of the second parameter,
   characterized in that
   the determined values of the first parameter, in which the values of the payload are known, are selected in dependence on the values of the second parameter so that the determined values of the first parameter at the different values of the second parameter are different, and
   the first parameter is an outreach of the crane and the second parameter is a main boom angle of the crane, and
   in case of a larger main boom angle, i.e. in a steeper set main boom, smaller values of the outreach are selected as sampling points than in case of a smaller main outreach angle.
2. Method in accordance with claim 1, characterized in that characterised in that the method includes an nth step in which the payload for the nth parameter is carried out by interpolation or extrapolation on the basis of the values of the payload determined in the (n-1)th step for different values of the nth parameter.
3. Method in accordance with one of claims 1 and 2, characterized in that the extrapolation is carried out on the basis of two sampling points.
4. Method in accordance with one of the preceding claims, characterised in that the parameters are input by hand or are detected by means of a sensor and are then used as the basis for the determination of the payload.
5. Method in accordance with claim 4, characterised in that the detection of parameter values is carried out by a sensor for parameters which have a specific value or can be rounded to a specific value.
6. Method in accordance with claim 4 or claim 5, characterised in that the values of the parameters revolving deck ballast and/or central ballast are detected by means of a sensor.
7. Method in accordance with one of the preceding claims, characterised in that the parameters are the setup parameters and/or state parameters of a crane.
8. Method in accordance with one of the preceding claims, characterised in that when a parameter limit is exceeded, instead of the value of the parameter measured by means of a sensor a different parameter value is set with which a lower payload results.