LIFTING GEAR, AND METHOD FOR DETERMINING SLACK ROPE ON THE LIFTING GEAR

Abstract

The present invention relates to lifting gear comprising a hoist rope, on which a load-receiving means is provided for receiving and lifting a load, and a determining device for determining slack rope on the hoist rope, wherein the aforementioned determining device comprises an inclination sensor system for detecting an inclination and/or a tilt rate and/or a tilt acceleration of the load-receiving means and provides a slack-rope signal if the detected inclination and/or tilt rate and/or tilt acceleration of the load-receiving means exceeds a predetermined limit value.

Claims

1. A lifting gear comprising: a hoist rope; a load receiver on the hoist rope, wherein the load-receiver is configured to receive and lift a load; and a determining device for determining slack rope on the hoist rope; wherein the determining device comprises an inclination sensor system for detecting an inclination and/or a tilt rate and/or a tilt acceleration of the load receiver and is configured to provide a slack-rope signal if the detected inclination and/or tilt rate and/or tilt acceleration of the load receiver exceeds a predetermined limit value.

2. The lifting gear of claim 1, wherein the inclination sensor system is configured to detect at least inclinations and/or tilt rates and/or tilt accelerations with respect to a horizontal tilting axis, wherein the inclination sensor system is configured to operate bi-axially or triaxially.

3. The lifting gear of claim 1, wherein the inclination sensor system comprises at least one sensor element attached to the load receiver.

4. The lifting gear of claim 1, wherein the inclination sensor system comprises an inertial measurement unit for providing acceleration signals and rotation rate signals to the load receiver.

5. The lifting gear of claim 1, wherein the determining device comprises a load sensor system for detecting the load acting on the hoist rope and/or for detecting a hoist rope force, and wherein the determining device is configured to provide a slack-rope signal when the detected load and/or the detected hoist rope force drops below a predetermined limit value and/or a drop rate of the detected load and/or hoist rope force exceeds a predetermined limit value.

6. The lifting gear of claim 5, wherein the determining device is configured to provide the slack-rope signal if the limit value for the detected load and/or hoist rope force is reached and the limit value for the inclination and/or a tilt rate and/or a tilt acceleration of the load receiver is reached.

7. The lifting gear of claim 6, wherein the determining device is configured to take into account adapted limit values for the inclination and load signals when the signals of the inclination sensor system and the load sensor system are taken into account in a linked manner.

8. The lifting gear of claim 1, wherein the load sensor system comprises a tensile force sensor and/or load sensor at an attachment point of the hoist rope.

9. The lifting gear of claim 1, wherein the load sensor system comprises a load sensing axis on a lower block of the load receiver or on another deflection pulley of a hoist rope drive.

10. The lifting gear of claim 1, wherein the determining device comprises an acceleration sensor system for detecting a first acceleration at a hoist winch and/or a hoist drive for the hoist rope and for detecting a second acceleration at the load receiver, and wherein the determining device is configured to provide a slack-rope signal when one of the first or second accelerations deviate from the other of the first or second accelerations above a predetermined amount.

11. The lifting gear of claim 10, wherein the acceleration sensor system on the hoist winch and/or the hoist drive comprises a rotational rate sensor and optionally a winding layer sensor and on the load receiver has an acceleration sensor for detecting upright accelerations, and wherein the acceleration sensor comprises an inertial measurement unit.

12. The lifting gear of claim 10, wherein the determining device is configured to take into account a proportionality factor corresponding to a course of the hoist rope when comparing the deviation of the first and second accelerations, and wherein the course of the hoist rope comprises a hoist rope reeving.

13. The lifting gear of claim 1, further comprising an accelerometer for determining an acceleration of the load receiver and/or the load from a load signal of a load sensor system on the basis of the equation F=m*a from the changes of the load signal.

14. The lifting gear of claim 1, further comprising a control device configured to automatically switch off and/or block a hoist drive and/or other lifting gear drives in the presence of the slack-rope signal.

15. The lifting gear of claim 14, wherein the control device is configured to only allow hoist movements that tension the hoist rope when the slack-rope signal is present.

16. The lifting gear of claim 15, wherein the hoist movements that tension the rope comprise a hoist up movement of the hoist drive and/or a luffing up movement of a boom.

17. The lifting gear of claim 1, wherein the determining device comprises a wireless communication interface for wirelessly receiving sensor signals.

18. A method for determining slack rope on a lifting gear comprising a hoist rope and a load receiver for receiving and lifting a load, wherein the load receiver is attached to the hoist rope, the method comprising: detecting an inclination and/or a tilt rate and/or a tilt acceleration of the load receiver by an inclination sensor system; and providing a slack-rope signal when the detected inclination and/or a tilt rate and/or a tilt acceleration of the load receiver exceeds a predetermined limit value.

19. The method of claim 18, further comprising: detecting by a load sensor system a load acting on the hoist rope and/or a hoist rope force; providing by the load sensor system a slack-rope signal if the detected load and/or detected hoist rope force drops below a predetermined limit value and/or a drop rate of the detected load and/or hoist rope force exceeds a predetermined limit value; and/or detecting by an acceleration sensor system a first acceleration at a hoist winch and/or a hoist drive for the hoist rope; detecting by the acceleration sensor system a second acceleration at the load receiver; and providing by the acceleration sensor system a slack-rope signal if one of the first and accelerations deviates from the other of the first and second accelerations above a predetermined amount.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The present invention is explained in more detail below with reference to preferred embodiments and the corresponding drawings. In the drawings show:

[0050] FIG. 1: a lifting gear in the form of a tower crane in a side view, the lifting gear being shown in normal operation with only a very small angle of inclination of the load-receiving means;

[0051] FIG. 2: the lifting gear of FIG. 1 with the load-receiving means resting on the ground and the relatively large angle of inclination of the load-receiving means and the resulting slack rope formation,

[0052] FIG. 3: a front view of the crane or lifting gear of FIG. 2, showing a lateral tilt of the load-receiving means resting on the ground and the corresponding strong angle of inclination, and

[0053] FIG. 4: a side view of the lifting gear of the preceding figures, in which a fixed deflection pulley causes slack rope to be inserted between the hoist winch and the deflection pulley, even though the load-receiving means does not rest on the ground.

DETAILED DESCRIPTION

[0054] As shown in the figures, the lifting gear 1 may be configured as a tower crane, for example, and comprise a boom 14 along which a trolley 2 is movable, from which a hoist rope 3 runs. Said boom 14 can, in the case of a tower crane, be seated on a tower, and the tower or boom may be rotatable relative to the tower about an upright axis, for example by a slewing gear. It is understood, however, that the lifting gear may be configured to be of another type of crane, for example, a telescopic boom crane with a boom that can be luffed up and down, or a derrick crane, maritime crane, loader crane, or other type of hoist.

[0055] The hoist rope 3 can be wound up and unwound by a hoist winch 10 and thus tightened and let down, wherein a hoist winch drive 11 can drive the hoist winch 10 and be controlled by a control device 7 of the lifting gear 1.

[0056] The hoist rope 3 carries a load-receiving means 15, which may comprise a load hook, for example, but also a lifting magnet or stop ropes. Independently of this, the hoist rope 3 can be reeved on the load-receiving means 15, which can have a lower block 4 for this purpose, see FIG. 1 or FIG. 4. As the figures show, the hoist rope 3 can be deflected around various deflection sheaves or pulleys 12.

[0057] In order to be able to detect the formation of slack rope in the area of the hoist rope 3, the lifting gear 1 can have a determining device 16, which can be part of the control device 7. Independently of this, the determining device 16 can be configured to operate electronically in the same way as the control device 7, for example to have a microprocessor and a program memory in order to be able to process a determining program stored in the memory with appropriate algorithms.

[0058] The determining device 16 receives sensor signals which can be evaluated by evaluation means 17 of the determining device 16, which may be configured to software program means, for example, for the presence of certain characteristics.

[0059] In this regard, the determining device 16 can receive signals from an inclination sensor system 18 that can detect or determine an inclination angle α of the load-receiving means 15 relative to the vertical and/or relative to a natural static orientation of the load-receiving means, cf. FIG. 2 and FIG. 3. Said inclination sensor system 18 thereby comprises at least one inclination sensor element, which may be attached to the load-receiving means 15 in order to follow and itself experience the tilts or inclinations of the load-receiving means 15.

[0060] In particular, said inclination sensor system 18 may include a so-called IMU 5, i.e., an inertial measurement unit on the load-receiving means 15 that provides acceleration signals and rotation rate signals that characterize or reflect acceleration and rotation rates at the load-receiving means 15.

[0061] Said inclination sensor system 18, in particular said IMU 5, is thereby advantageously configured to detect inclinations and/or tilts and/or rotational speeds and/or accelerations about at least one horizontal axis of rotation, preferably about two horizontal axes of rotation perpendicular to each other. By means of a two-axis inclination and/or rotation rate and/or rotation acceleration detection, in particular a lateral tilting of the load-receiving means 15, as shown in FIG. 3, and also a forward or backward pitching of the load-receiving means 15, as shown in FIG. 2, can be detected. In particular, the inclination sensor system 18 can detect at least one tilt about a tilting axis parallel to the deflection axis of the lower block 4 and one tilt about a horizontal tilting axis perpendicular thereto.

[0062] Advantageously, the rotation rates can also be detected triaxially. Similarly, translational accelerations can also be triaxially detected. Advantageously, said IMU 5 can detect translational accelerations with respect to three axes and also rotational rates or rotational accelerations with respect to three axes.

[0063] In normal hoist operation, as shown in FIG. 1, most of the acceleration due to gravity g acts in the Z direction, cf FIG. 1, so that the angle α of the load-receiving means 15 with respect to the vertical is usually zero or very small. The hoist rope 3 generally oscillates only a few degrees relative to the vertical, so that the angle of inclination of the load-receiving means 15 is also correspondingly small.

[0064] However, when the load-receiving means 15 touches the ground, as shown in FIG. 2 and FIG. 3, the orientation of the load-receiving means 15 changes significantly. The angle of inclination a with respect to the vertical becomes relatively large and also changes very rapidly when the lower block 4 touches down on the substrate 9.

[0065] If the inclination sensor system 18 detects such an inclination angle α exceeding a predetermined limit value and/or a tilt rate and/or tilt acceleration exceeding a predetermined limit value for the tilt rate or tilt acceleration, which can be determined by said evaluating device 17 by comparison, the determining device 16 can assume that slack rope is forming and output a corresponding slack-rope signal.

[0066] The control device 7 can switch off the hoist drive 11 when such a slack-rope signal is present and, if necessary, also switch off other lifting gear drives 8, such as a slewing drive or a luffing drive for the boom 14, in order to prevent further lowering of the load-receiving means 15 or dragging of the load-receiving means 15 over the ground.

[0067] Advantageously, the control device 7 can block all hoist movements when the determining device 16 has determined slack rope, preferably with the exception of hoist movements that can tighten the hoist rope 3 again, such as by a hoist up movement of the hoist drive 11.

[0068] The control device 7 can be configured to block the other lifting gear drives 8 until the hoist rope 3 is tensioned again or the slack rope is eliminated by the hoist up movement, which can be detected, for example, by a decrease or drop of the angle of inclination a by the inclination sensor system 18. If, for example, the angle of inclination a falls below a predetermined limit value, which can be the same as the first limit value mentioned above, but can also deviate from it, for example be smaller, the determining device 16 assumes that there is no longer any slack rope, whereupon the control device 7 can release the lifting gear drives 8 again.

[0069] By blocking further lifting gear drives, it is possible to prevent the lower block 4 from dragging on the ground 9, thus avoiding further damage caused by the sticking of pebbles or sand.

[0070] Advantageously, the determining device can also receive signals from a load or rope force sensor 19 that provides a load signal characterizing the rope force acting in the hoist rope 3. For example, said load sensor system 19 can comprise a load sensor 6 or a hoist rope sensor that can, for example, detect the rope force of the hoist rope 3 at the attachment point of the hoist rope 3, cf. FIGS. 1-4. Alternatively or additionally to such a rope load sensor 6 at the attachment point of the hoist rope 3, the load sensor system 19 can also comprise, for example, a load sensing axis at the lower block 4 and/or have load sensing axes at other deflection pulleys 12, by means of which there can be determined rope tensile forces or corresponding reaction forces at the deflection pulleys.

[0071] If the load signal from the load sensor system 19 characterizing the rope tensile force drops below a predetermined limit value or if the drop rate of said load signal exceeds a predetermined limit value, the determining device 16 can assume that the slack rope has been formed. Said limit value for the load signal can take into account the mass of the load-receiving means 15 including the lower block 4, since when the load-receiving means 15 is suspended, at least the weight of the load-receiving means 15 always pulls on the hoist rope, so that when the load signal drops to a lower value, it can be assumed that the load-receiving means 15 is resting on the lower block 9.

[0072] Advantageously, the monitoring of said load signal of the load sensor system 19 is linked to the monitoring of the angle of inclination a, for example in such a way that, in addition to exceeding a limit value for the angle of inclination a and/or for the tilt rate, it is also required that the load signal drops below a predetermined limit value and/or that the drop rate of the load signal rises above a predetermined limit value before the determining device provides the slack-rope signal. If necessary, the limit values can also be dynamically adjusted, as explained at the beginning, in order to output a slack-rope signal, for example, even if the signals from the inclination sensor system 18 and the load sensor system 19 do not yet reach the respective limit value by themselves, but are both just short of it.

[0073] As FIG. 4 illustrates, slack rope can form not only when the load-receiving means is resting on the ground 9, but also when the hoist rope 3 is blocked between the hoist winch 10 and the load-receiving means 15, for example by a frozen deflection pulley 13, see FIG. 4. In order to also be able to reliably detect such cases of slack rope formation, the determining device 16 or its evaluation means 17 can compare accelerations at a hoist winch 10 or hoist drive 11 with accelerations at the load-receiving means 15. In proper operation, a predetermined hoist winch or drum acceleration, taking into account the changing lever arm due to multiple layers of winding, induces a certain acceleration of the hoist rope 3 in the area of the hoist winch 10, which then results in a corresponding acceleration at the load-receiving means 15, proportionally changed by the reeving. If these accelerations deviate from each other or do not correspond to the ratio corresponding to the deflection geometry and reeving geometry, it can be assumed that the slack rope has been formed.

[0074] Preferably, an acceleration sensor system 20 can detect said accelerations at the hoist winch 10 or hoist drive 11 on the one hand and at the load-receiving means 15 on the other hand, for example by means of a drum sensor for detecting the drum speed or acceleration and a winding layer sensor for detecting the number of winding layers on the drum. A corresponding acceleration sensor system can be attached to the load-receiving means 15, which can detect acceleration in the upright acceleration direction. This can be, for example, the aforementioned IMU 5, which provides corresponding acceleration signals.

[0075] The acceleration at a hoist winch 10 and the acceleration at the load-receiving means 15 are compared with each other by the evaluation means 17, whereby the transmission or reduction ratio can be taken into account by the reeving. If the accelerations deviate from each other by a predetermined amount or by a tolerance limit, the determining device 16 can provide a slack-rope signal. When such a slack-rope signal is present, the control device 7 can, in particular, switch off the hoist drive 11 or allow only hoist-up movements.