METHOD FOR DETERMINING THE ROPE REEVING OF A PULLEY BLOCK

Abstract

The disclosure relates to a method for determining the number of rope reevings of a pulley block with a top block and a bottom block, wherein the rope path of at least one rope line of the pulley block, which is covered during a time window, is detected and compared with at least one rope path of a further rope line covered within the time window and/or with the height difference between top block and bottom block changed within the time window, in order to determine the number of rope reevings of the pulley block.

Claims

1. A method for determining a number of rope reevings of a pulley block with a top block and a bottom block, wherein a rope path of at least one rope line of the pulley block, which is covered during a time window, is detected and compared with at least one rope path of a further rope line covered within the time window and/or with a height difference between the top block and the bottom block changed within the time window, in order to determine the number of rope reevings of the pulley block.

2. The method according to claim 1, wherein the rope path of at least one rope line is measured by a rope pulley of the pulley block forming the rope line and/or is detected by at least one additional measuring roller which rolls off on the rope line.

3. The method according to claim 2, wherein the rope path is effected by means of an incremental revolution measurement of the rope pulley or measuring roller.

4. The method according claim 1, wherein the rope path of the first rope line of the pulley block is measured by a hoisting winch of the pulley block, wherein the measured rope path corresponds to the hoisting rope wound or unwound within the time window and a measurement is carried out by an incremental revolution measurement on the hoisting rope winch.

5. The method according to claim 1, wherein the change of the height difference between the top block and the bottom block is effected by a rope path measurement on a last line of the pulley block.

6. The method according to claim 1, wherein the change of the height difference between the top block and the bottom block is effected by means of a mechanical length sensor and/or by means of an optical, laser-based and/or runtime-based measurement method.

7. The method according to claim 1, wherein at least two rope path measurements are carried out on rope lines of the pulley block spaced apart as far as possible.

8. The method according to claim 4, wherein the rope path of the first rope line is determined by the rope path wound onto or unwound from the hoisting rope winch and is divided by the detected change of the height difference between the top block and the bottom block, wherein the resulting quotient corresponds to the number of rope reevings.

9. The method according to claim 4, wherein the rope path of the first rope line is determined by the rope path wound onto or unwound from the hoisting rope winch and is placed in relation to the determined rope path of a succeeding rope line of the pulley block.

10. The method according to any of the preceding claims, characterized in that the method is executed by a crane control unit of a crane in order to determine the number of rope reevings at the hook block or another pulley block of the crane.

11. A device for carrying out a method for determining a number of rope reevings of a pulley block with a top block and a bottom block, wherein a rope path of at least one rope line of the pulley block, which is covered during a time window, is detected and compared with at least one rope path of a further rope line covered within the time window and/or with a height difference between the top block and the bottom block changed within the time window; wherein the device consists of a measuring device for detecting the at least two rope paths during the time window and at least one evaluation unit for calculating the rope reeving on the basis of measurement values.

12. A crane control unit suitable for communication with at least two sensors for a rope path measurement on a pulley block, wherein the crane control unit is programmed to carry out a method for determining a number of rope reevings of the pulley block with a top block and a bottom block, wherein a rope path of at least one rope line of the pulley block, which is covered during a time window, is detected and compared with at least one rope path of a further rope line covered within the time window and/or with a height difference between the top block and the bottom block changed within the time window.

13. The crane control unit according to claim 12, further comprising a program application stored on a data carrier for the control unit for executing the method.

14. The method according to claim 7, wherein the at least two rope path measurements are carried out on the first and last moving rope lines of the pulley block.

15. The method according to claim 9, wherein the number of rope reevings is determined by matching a calculated ratio from both rope path values with known reference values.

Description

BRIEF DESCRIPTION OF FIGURES

[0025] Further advantages and properties of the disclosure will be explained in detail below with reference to exemplary embodiments. In the drawing

[0026] FIG. 1 shows a first exemplary embodiment of the method of the disclosure, which provides a path measurement between trolley head and hook block,

[0027] FIG. 2A shows a second exemplary embodiment of the method by means of a path measurement via a rope pulley,

[0028] FIG. 2B shows a reference table for the determination of reeving according to the exemplary embodiment of FIGS. 2A and 3, and

[0029] FIG. 3 shows a third exemplary embodiment of the method, which performs a path measurement directly on the rope line.

DETAILED DESCRIPTION

[0030] The idea underlying the method of the disclosure consists in determining the number of rope lines of a pulley block by comparing synchronously covered rope paths of different rope lines of the pulley block. Alternatively, the rope path of a rope line can also be compared with the path between top block and bottom block, i.e. the change of the vertical distance between top block and bottom block.

[0031] Concretely, the idea of the disclosure will be explained using the example of a crane which as load lifting means comprises a hook block. Due to the course of the hoisting rope over the trolley head of the crane boom to the hook block and back, there is formed a pulley block which is schematically indicated in FIG. 1. Concretely, the pulley block on the one hand is formed by the neck roller 10a mounted on the crane boom together with further rope pulleys 10b, 10c of the trolley head 10 and on the other hand by the loose rope pulleys 20a, 20b, 20c of the hook block 20. The hoisting rope 50 extends from a non-illustrated hoisting rope winch of the crane along the boom in the direction of the trolley head 10 and is redirected there to the hook block 20 via the neck roller 10a. A multiple reeving between roller head 10 and hook block 20 is realized by the further rope pulleys 10b, 10c, 20a, 20b, 20c until the hoisting rope 50 ultimately is fastened to the boom at the fixed rope point 51. In sum, a pulley block with a total of six rope pulleys or six reevings is formed.

[0032] The crane control unit now can automatically detect the number of rope reevings of the hoisting rope 50 by using the method according to the disclosure. The necessary path measurement on the rope lines may be effected directly on the hoisting rope 50 within a certain time interval, during which the hook block 20 is let down or lifted in a defined way. What is necessary at least are the values at two different points of the pulley block. The crane control unit likewise can determine the average speed from the measured path lengths and the determined time and via the ratio of the covered distances in the same time interval can determine the reeving in a pulley block with sufficient accuracy.

[0033] The exemplary embodiment of FIG. 1 here provides a rope path measurement of the first rope line, which is carried out by a suitable measuring device of the hoisting rope winch. By an incremental gyrometer of the hoisting rope winch, the unwound rope path can be determined, which corresponds to the rope path of the first line of the pulley block.

[0034] Furthermore, the system comprises a path measuring device 60 which detects a change of the height difference between hook block 20 and top block 10 or trolley head 10 of the crane boom. The concrete configuration of this path measuring device in principle is arbitrary, but a mechanical length sensor installed between hook block 20 and trolley head 10 is found to be advantageous. Alternatively, the difference in height might also be effected by means of optical, laser-based or runtime measurement-based measurement methods. By way of example, reference here is made to a suitable radar sensor system, lidar sensor system or sensors for the time domain reflectometry. Both sonar and GPS sensors likewise are suitable for a distance measurement in vertical direction.

[0035] For the execution of the method the hook block 20 now is lowered by the control unit. For this purpose, for example a rope length of a total of 6 m is unwound from the hoisting rope winch in the time interval x. This rope length is measured directly at the hoisting rope winch.

[0036] The first line of the pulley block completely receives the unwound 6 m of rope, so that the corresponding ratio of the first line is referred to as 6/6. As the total of 6 m of unwound rope length are distributed over the total of six rope lines of the pulley block, a defined change of the height difference between hook block 20 and trolley head 10 ultimately is obtained, which generally corresponds to an n-th fraction of the total rope length of 6 m let down from the hoisting rope winch, wherein n represents the number of reevings.

[0037] When the change of the height difference hence is detected by means of a length sensor, this measurement value can be compared with the measurement value of the first rope line or the rope length unwound and from this ratio the number S of reevings of the pulley block can be determined in the final analysis. When a rope length of 6 m hence is unwound by the hoisting winch, the hook block 20 must move downwards by a total of 1 m within the same time interval in the configuration of the pulley block depicted in FIG. 1. When lifting the hook block 20 this principle is to be used in a correspondingly adapted form.

[0038] Hence, it generally applies that the number S of reevings can be determined as follows:

[00001]$S=\frac{\mathrm{rope}.Math..Math.\mathrm{path}.Math..Math.1.Math.\mathrm{st}.Math..Math.\mathrm{line}.Math..Math.\left(\mathrm{time}.Math..Math.\mathrm{interval}.Math..Math.x\right)}{\begin{array}{c}\mathrm{height}.Math..Math.\mathrm{difference}.Math..Math.\mathrm{hook}.Math..Math.\mathrm{block}-\\ \mathrm{trolley}.Math..Math.\mathrm{head}.Math..Math.\left(\mathrm{in}.Math..Math.\mathrm{time}.Math..Math.\mathrm{interval}.Math..Math.x\right)\end{array}}=\frac{6.Math..Math.m}{1.Math..Math.m}=6$

[0039] When no integer calculation results are obtained in practice due to measurement errors etc., the same must be rounded correspondingly.

[0040] The same principle can also be executed with a rope path measurement on different rope lines of the pulley block. In the case of a sixfold reeving as shown in FIG. 2A, the first line covers a certain rope path during the time interval x. By lifting or lowering the hook block 20, this rope path of the first line is distributed over the lines 2-6 present in the reeving. Now, the path per time interval of at least one further line can be measured and be placed in relation to the path per time interval of the first line. This ratio determined by the control unit can then be associated with a concrete reeving by comparing the determined ratio against a reference table, as it is shown for example in FIG. 2B. In the Table of FIG. 2B the respective ratio between the rope path in a particular cable pulley is compared with the entire rope path of the first rope line for different pulley block constellations, i.e. a different number of reevings.

[0041] The pulley block shown in FIG. 2A differs in its construction from the arrangement of FIG. 1 only by the fact that no path measuring device 60 is provided for detecting the height difference of the hook block 20, but instead the rope path of the fifth rope line in the fifth rope pulley of the pulley block, i.e. in the last rope pulley 10c of the trolley head 10, is measured. This rope path during the time interval x can be detected by an incremental gyrometer installed in the roller 10c and can be compared with the rope length let down from the hoisting rope winch. When the hook block 20 for example is let down by a defined rope length by means of the control unit, i.e. a defined rope length of a total of 6 m is unwound from the hoisting rope winch in the time interval x, this is detected by the incremental revolution measurement in the hoisting rope winch.

[0042] This measurement value of 6 m now is placed in relation to the measurement value in the roller 10c, which here is about 2 m. In general, in a path measurement on the roller 5 (rope pulley 10c) the following is obtained for the reference value S:

[00002]$S^{}=\frac{\mathrm{rope}.Math..Math.\mathrm{path}.Math..Math.\mathrm{roller}.Math..Math.5.Math..Math.\left(\mathrm{in}.Math..Math.\mathrm{time}.Math..Math.\mathrm{interval}.Math..Math.x\right)}{\mathrm{rope}.Math..Math.\mathrm{path}.Math..Math.1.Math.\mathrm{st}.Math..Math.\mathrm{line}.Math..Math.\left(\mathrm{in}.Math..Math.\mathrm{time}.Math..Math.\mathrm{interval}.Math..Math.x\right)}=\frac{2.Math..Math.m}{6.Math..Math.m}=0.33$

[0043] By matching this calculated reference value S with the table entries of FIG. 2B, it thus can be detected immediately that the number of reevings S is 6.

[0044] Alternatively, an example for a pulley block with eight reevings can be determined, wherein here the rope path on the seventh rope pulley, i.e. the last rope pulley of the trolley head 10, is measured by way of example. The reference value S here is calculated as follows:

[00003]$S^{}=\frac{\mathrm{rope}.Math..Math.\mathrm{path}.Math..Math.\mathrm{roller}.Math..Math.7.Math..Math.\left(\mathrm{in}.Math..Math.\mathrm{time}.Math..Math.\mathrm{interval}.Math..Math.x\right)}{\mathrm{rope}.Math..Math.\mathrm{path}.Math..Math.1.Math.\mathrm{st}.Math..Math.\mathrm{line}.Math..Math.\left(\mathrm{in}.Math..Math.\mathrm{time}.Math..Math.\mathrm{interval}.Math..Math.x\right)}=\frac{2.Math..Math.m}{8.Math..Math.m}=0.25$

[0045] A comparison with column seven (seventh rope pulley) of the Table of FIG. 2B shows a correspondence for a pulley block constellation with 8 reevings.

[0046] In principle, it is expedient to choose the distance between the rope lines under consideration as large as possible so that the difference of the rope paths is as large as possible. It is also expedient to perform the rope path detection at the rope pulleys of the trolley head, as here both the power supply and the signal transmission from the rope pulley is simplified.

[0047] FIG. 3 now shows a last exemplary embodiment of the method according to the disclosure. Here, the rope path of one of the rear rope lines now is not accomplished via a rope pulley 10a, 10b, 10c of the trolley head 10, but instead the same is measured by means of a separate measuring roller 70 which rolls off on the rope line under consideration. The measuring roller 70 comprises at least one roller which rests against the rope and provides for a revolution measurement (incremental path measurement). The determination of reeving would then be effected analogous to the described embodiment as shown in FIG. 2A.