EP4247746A1

EP4247746A1 - Lifting gear, and method for determining slack rope on the lifting gear

Info

Publication number: EP4247746A1
Application number: EP22702259.7A
Authority: EP
Inventors: Clemens Maier; Tobias Englert
Original assignee: Liebherr Werk Biberach GmbH
Current assignee: Liebherr Werk Biberach GmbH
Priority date: 2021-01-27
Filing date: 2022-01-27
Publication date: 2023-09-27
Also published as: WO2022162066A1; US20230391588A1

Abstract

The present invention relates to lifting gear comprising a hoist rope (3), on which a load-receiving means (15) is provided for receiving and lifting a load, and a determining device (16) for determining slack rope on the hoist rope (3), wherein the aforementioned determining device comprises an inclination sensor system (18) for detecting an inclination and/or a tilt rate and/or a tilt acceleration of the load-receiving means (15) and provides a slack-rope signal if the detected inclination and/or tilt rate and/or tilt acceleration of the load-receiving means (15) exceeds a predetermined limit value.

Description

Hoist and method of determining slack in the hoist

The present invention relates to a hoist with a hoist rope, on which a load handling device for receiving and lifting a load is provided, and a determination device for determining slack rope in the hoist rope. The invention also relates to a method for determining slack rope on such a hoist.

In the case of hoists such as tower cranes or other cranes for construction sites, maritime applications or other purposes, the machine operator normally makes sure manually or visually that the load hook or the load handling device is not lowered too far in order to avoid slack rope. Because of such a slack rope formation, proper rope guidance would no longer be guaranteed, which can lead to problems in various areas of the hoist rope system.

On the one hand, there can be problems with the load handling device itself, on which the hoist rope is usually reeved and deflected around a bottom block or one or more deflection pulleys. If the bottom block is lowered too far, it stands up on the ground and proper rope guidance is no longer possible guaranteed. When tightening again, the bottom block can tilt and, in the worst case, rotate 180° around the boom axis. As a result, the hoist rope is no longer guided upwards over the deflection pulleys and can be damaged by scraping on the bottom block. At the very least, the bottom block has to be cleaned afterwards and moved back into the correct position manually.

Even if there is no tilting when tightening again, the hoisting rope can be damaged by dirt, for example if gravel, sand or soil with granular substances adheres to the rope lying on the ground. As a result, damage to the deflection rollers can also occur. Depending on the movement of the hoist, the bottom block can also be dragged along the ground by actuating the other drives of the hoist, which can lead to further damage to the bottom block and the hoist rope, for example if the hoist with its boom from which the hoist rope runs off Performs a rotary movement in which the load handling device is dragged along the floor.

On the other hand, there can also be problems in the area of the hoist winch. If, for example, the rope is slack on the hoist drum as a result of the load hook touching down on the ground or due to a blocked hoist rope or a blocked deflection pulley, which may be frozen, for example, this leads directly or at the latest when the hoist rope is tightened again to an untidy winding. If the hoisting rope is wound up on the hoisting drum in several layers, the hoisting rope can easily cut between two rope courses of an underlying rope layer that is not quite tightly wound up. In addition, jerky loads can also cause further damage, such as defective ball bearings on the deflection rollers.

Even if the machine operator is working attentively, the aforementioned slack rope formation can sometimes occur, for example if the load hook is lowered behind the edge of a building in a non-visible area. In addition, it can also lead to attention deficits when tiring activities such as repeated lifting distances have to be driven.

It has therefore already been considered to generally limit the sinking depth of the load hook in order to prevent the bottom block from touching down on the ground by scaling a maximum sinking depth for the respective construction site. Here, however, the problem arises that the construction site environment is usually not level in practice, so that the countersinking depth would have to be defined differently in some areas, which can be a complex process depending on the construction site. In addition, the construction site environment is constantly changing as construction progresses. If, for example, a crane has to lift loads into a pit or onto a roof, the lifting device can rest on different levels due to the different heights of the pit floor and the roof, especially if the pit level or the roof height changes as the construction site progresses.

Proceeding from this, the present invention is based on the object of creating an improved hoist and an improved method for determining slack rope which can avoid the disadvantages of the prior art and further develop the latter in an advantageous manner. In particular, a reliable slack rope determination is to be created that can reliably detect slack rope even in complex hoist environments with changing surrounding contours without complex mapping of the environment that has to be updated again and again and also with other slack rope problems such as freezing pulleys.

According to the invention, the stated object is achieved by a hoist according to claim 1 and a method according to claim 15. Preferred developments of the invention are the subject matter of the dependent claims.

According to a first aspect, it is therefore proposed to monitor the tilting of the load handling device and to use it as an indicator for slack rope. If the load handling device tilts too much and/or too quickly, it is assumed that the hoist rope is no longer properly tensioned and that slack rope has formed. According to the invention, the determination device for determining slack rope comprises an inclination sensor system for detecting an inclination and/or a tipping speed and/or a tipping acceleration of the load handling device and provides a slack rope signal when the detected inclination and/or angular velocity and/or angular acceleration of the load handling device exceeds a predetermined value .

The limit value mentioned for the inclination and/or angular velocity and/or angular acceleration is advantageously selected in such a way that during operation “normal” inclinations or angular velocities or accelerations, such as those that occur with pendulum movements of the hoist rope or rotary movements of the boom, do not lead to an Lead triggering of the slack rope signal and are not interpreted by the determination device as an indicator of slack rope formation. The slack rope signal is only provided when the load handling device, for example the lower block of the load hook, experiences a tilting that exceeds the normal pendulum movements or rotary travel paths of the load handling device in terms of tilting angle and/or angular velocity and/or angular acceleration. In particular, the limit value mentioned is selected to be sufficiently large in order not to cause any incorrect response in the event of pendulum movements.

For example, an angle of inclination of the bottom block of a few degrees from the vertical can be interpreted as a normal pendulum movement, while a tilt of more than 10° or more than 20° from the vertical can be interpreted as touching down on the ground or an obstacle, and then give a slack rope signal.

Alternatively or additionally, very small angular speeds of, for example, only one degree per second, such as occur, for example, when a load hook moves back and forth by, for example, 5° in ten seconds, for example. oscillates, can be interpreted as a normal pendulum movement, while the determination device can interpret higher angular velocities of several, for example 10° per second, as the load hook hitting the ground, in order then to output a slack rope signal.

In an advantageous development of the invention, a separate limit value can be specified for each of the named parameters of inclination angle and angular velocity and possibly also angular acceleration, so that a slack rope signal is output when one of the named parameters reaches or exceeds the limit value.

Advantageously, the limit values for the parameters mentioned can also be dynamically adjusted as a function of one another, for example in such a way that a slack rope signal is still output if the limit value for the inclination angle is just missed and at the same time the limit value for the angular velocity of the load handling device is just missed. For example, if the load-carrying device tilts very quickly, which in itself does not yet reach the limit value, but is close to it, the limit value for the angle of inclination can be lowered a little, in order to then possibly issue a slack rope signal if several sizes are close are at their limit.

In principle, the slack rope signal provided by the determination device can be further processed in various ways. If the control or further processing is only semi-automatic, the said slack rope signal can be output by a display device, for example in the form of a hazard warning signal on a display and/or in the form of an acoustic warning signal for the machine operator, who can then stop the drives.

Alternatively or additionally, however, the hoist can advantageously also have a control device which, in the presence of said warning signal, ie then, when the determination device has determined slack rope, automatically switches off at least the hoist drive for the hoist rope or blocks lowering movements in order to stop further lowering of the hoist rope. Advantageously, when the slack rope signal is present, the control device can generally switch off all drives of the hoist or block movements that would result in further lowering of the load suspension device and/or cause the load suspension device to drag along over the floor. For example, a luffing of a jib can be stopped and/or a travel of a trolley, from which the hoist rope runs off, along the jib and/or a twisting of the jib about an upright axis can be switched off or prevented in order to prevent the load handling device from dragging along on the ground avoid.

In general, when the slack rope signal is present, the control device can only allow hoisting gear movements that reduce slack rope and/or tension the hoist rope and/or do not cause the hoist rope or load handling device to drag along on the ground. In particular, the control device can permit upward movements of the hoisting rope drive and/or the boom and prevent opposite movements of the hoisting gear, which could cause even more slack rope and/or cause the lifting device to drag along on the ground.

In an advantageous development of the invention, the above-mentioned inclination sensor system, with the aid of which the angle of inclination of the load-handling device relative to the vertical and/or the angular velocity and/or the angular acceleration of the load-handling device is detected, can comprise at least one sensor element that is attached to the load-handling device and detects the tilting movements of the load-handling device participates. By attaching the at least one inclination sensor to the load handling device itself, the inclination or the angular velocity or the angular acceleration can be determined directly and without a time delay, as a result of which a precise determination of the slack rope is made possible. At the same time, problems such as an interruption in the "field of view" or the detection area can occur of the sensors, as can occur with sensors arranged at a distance from the load hook, can be avoided.

The sensor can be attached to different sections of the load-carrying means, for example the storage rack for a deflection block, a section of the load hook or a panel section around the bottle storage rack.

A signal transmission from the sensor element on the load handling device to the evaluation device of the named determination device, which can for example be part of the hoist control device, can advantageously take place wirelessly, for example via radio, WLAN or Bluetooth or another wireless signal transmission standard. Alternatively or additionally, however, a wired transmission to the evaluation device can also take place, for example via the hoist rope itself. Alternatively, it can also be provided to carry out the evaluation in or on the sensor element, in which case the named evaluation device can be arranged on the sensor element.

The inclination sensor system can detect inclinations of the load handling device on one axis or preferably on multiple axes and can advantageously be at least designed to detect tilting of the load handling device about one or preferably two mutually perpendicular tilting axes, each aligned horizontally.

Advantageously, the inclination sensor system can include an inertial measuring device on the load handling device, which is sometimes referred to as an IMU.

Such an inertial measuring device attached to the load-carrying means can in particular have acceleration and yaw rate sensor means for providing acceleration and yaw rate signals, which on the one hand indicate translational accelerations along different spatial axes and on the other hand yaw rates or gyroscopic signals with respect to different spatial axes in order to grasp. In this case, rotation speeds, but in principle also rotation accelerations or even both, can be provided as rotation rates.

Advantageously, the inertial measuring device can detect accelerations with respect to three spatial axes and yaw rates about at least two or preferably also three spatial axes. The acceleration sensor means can work on three axes and the gyroscope sensor means can work on two or three axes. In particular, the gyroscope sensor means can be designed to detect yaw rates with respect to two horizontal axes that are perpendicular to one another, in order to detect lateral tilting movements and forward or backward pitching movements of the load handling device. Internal twists along the hoist rope axis are less interesting for detecting slack rope formation.

From the signals of said inertial measuring device, at least the inclination of the load-carrying means relative to the vertical is advantageously determined. B. by means of a complementary filter or another filter, high-frequency components from the gyroscope signals and low-frequency components from the direction of the gravitational vector are determined and can be combined to determine the tilting of the load-carrying means. However, other evaluations of the signals of the inertial measuring device are also possible.

According to a further aspect of the present invention, the determination of slack rope can also be achieved or refined in that a load sensor detects the load acting on the hoist rope and/or the rope force present in the hoist rope, with the determination device being able to provide the slack rope signal when there is a decrease and/or a rate of decrease of the detected load and/or the detected cable force exceeds a predetermined limit value.

In principle, it would also be possible to assume slack rope and to provide a slack rope signal if only the detected load or the detected Cable force itself falls below a certain limit, for example goes to zero. However, since this requires a relatively high accuracy of the load and/or force sensor, the rate of decrease or its derivation can advantageously be monitored and compared with a limit value in order to provide a slack rope signal in particular in the event of a very strong or very rapid decrease, since then it can be assumed that the load-carrying device hit the ground or that the bottom block was lifted up or down with a jerk.

In particular, the above-mentioned comparison of the recorded decrease or the recorded decrease speed of the load or the cable force with a corresponding limit value can be linked to the aforementioned checking and monitoring of the inclination or angular speed or angular acceleration of the load handling device in order to refine the determination of slack rope causes, so to speak achieve circumstances. As a result, reliable statements can be made about the presence of slack rope, even with limited measurement accuracies with regard to the hoisting rope force or the load pulling on the hoisting rope.

Typically, the measurement accuracy of load measuring axles installed in deflection blocks is relatively limited, so that the recorded load value on the load measuring axle means that the relatively light bottom block or load hook can only be detected with limited certainty and speed on the ground. A further complication in this respect is that typically the sinking depth and thus the rope weight are not exactly known or are not measured exactly. If the measurement signal from the load sensors and its evaluation, i.e. the comparison of the decrease or the decrease speed of the recorded load or cable force with a limit value, is combined or merged with the evaluation of the inclination or angular velocity or angular acceleration of the load handling device, an overall even safer slack rope detection can be implemented. Said load sensor system can include at least one load measuring axis, which can be installed, for example, on the bottom block on which the hoist rope on the load handling device is deflected, so that the load signal indicates the weight of the load handling device and the load that may be attached to it, essentially independently of the lowering depth.

Alternatively or additionally, however, a load measuring axis can also be provided, for example on the deflection pulley, via which the hoist cable is lowered from the boom.

Alternatively or additionally, however, other load sensors can also be installed, for example strain gauges on a trolley or other sensor elements.

Irrespective of this, a load signal can advantageously be transmitted wirelessly to the evaluation device of the determination device.

The sensors for the determination device can be easily retrofitted by means of wireless signal transmission and thus a slack rope determination can be provided on older cranes or hoists.

According to a further aspect, the slack rope determination can also include an acceleration sensor system, by means of which the accelerations at two different sections of the hoist rope system can be detected, in order to be able to conclude that slack rope formation has occurred if the accelerations deviate from one another. Advantageously, the named acceleration sensor system is designed to detect an acceleration of a hoisting rope system section in the area of the load handling device on the one hand and an acceleration of a hoisting rope system section in the area of the hoisting rope drive or the hoisting rope winch on the other hand, since the acquisition of the accelerations in the end sections of the hoisting rope system Problems causing slack rope in the entire intermediate area can be detected, for example by jammed or frozen deflection pulleys or jammed hoist rope sections or the like.

In particular, the acceleration sensor system can be designed to detect the acceleration of the hoist drive or the hoist winch or drum itself and, on the other hand, to detect the acceleration of the load handling device, for example the bottom block. In principle, the concrete detection can be accomplished in different ways. For example, a speed of the deflection pulley could be determined on the bottom block, since a specific hoisting cable speed would induce a specific deflection sheave speed if the cable runs correctly. In particular, however, an acceleration sensor system can also be attached to the bottom block or to the load handling device, which can detect vertical or at least approximately upright accelerations in order to be able to directly determine the accelerations when lowering or raising the load handling device.

In the area of the hoist drive or the hoist winch, for example, a rotational speed sensor can be provided on the hoist drum, possibly combined with a coil layer sensor, in order to be able to detect the influence of the coil layers on the rope speed. Alternatively or additionally, however, an acceleration sensor can also be provided, which, for example, detects the rope speed running directly from the drum and determines the acceleration in the lifting drive area from its derivation.

Alternatively or additionally, the acceleration of the load can also be determined via the load sensors. The relationship F = m * a, ie force = mass * acceleration, results in a higher hoist rope force when accelerating and a lower hoisting force when braking. The acceleration of the load can be determined from the change in the hoist rope force.

The determination device for determining slack rope can be designed to the acceleration of the hoist drive or on the hoist winch with the to compare the acceleration on the load-carrying device, whereby reduction or transmission factors can be taken into account in this comparison due to the reeving of the hoist rope at the bottom block or at other rope sections. If, for example, the load hook is simply reeved, the rope acceleration on the hoist winch is halved up to the load hook, so that the hoist rope itself unwinds correctly if half the acceleration occurs on the load hook compared to the rope acceleration on the hoist winch.

If, for example, a lifting movement is specified by the controller, e.g. B. "Hoist off", the hoist winch unwinds the hoist rope, with the winch and hoist rope first being accelerated. This in turn must cause a proportional acceleration of the load hook or the bottom block or the load handling device. However, if these two accelerations differ from one another, it can be assumed that a deflection or the hoisting rope is blocked in the rope drive, in particular if the deviation between the two accelerations exceeds a predetermined level. For example, the hoist rope could be frozen to a pulley, causing slack on the hoist drum as the hoist drum unwinds.

If the determination device determines that the difference in acceleration is too great, a slack rope signal can be output, which can then be processed by the control device in the aforementioned manner to switch off the hoist drive or possibly another crane drive.

In order to refine the comparison between the acceleration on the hoist winch and the acceleration on the load handling device, further accelerations that are induced by movements of other hoist elements on the load handling device can be recorded and taken into account in the comparison. If, for example, a crane jib is luffed out parallel to the actuation of the hoist winch, if the hoist cable runs correctly, there should also be a downward acceleration due to the jib movement in addition to the acceleration from the hoist winch movement. The determining device can also do this also have an acceleration sensor system for detecting the acceleration of such additional crane elements as for example the crane boom and take into account the comparison of the acceleration of the load handling device with the acceleration on the hoist winch.

As an alternative or in addition to a comparison of two accelerations at different points on the hoisting cable system, a comparison of two speeds at different points in the hoisting cable system can also be provided in a development of the invention in order to be able to identify slack cable. For example, a rotary encoder on the hoist motor or the hoist cable winch can provide a speed on the hoist drive and another rotary encoder, for example on the bottom block on the load hook, can provide a speed signal there.

Alternatively or additionally, an acceleration signal from the aforementioned IMU can also be integrated over a limited period of time, for example over the entire acceleration process, in order to determine the speed of the lower block and to compare it with the speed on another hoist rope section, for example the speed on the hoist drive, in order to determine slack rope from this .

Advantageously, such an integration can only be carried out over a limited period of time in order to avoid instabilities such as would result from permanent integration due to offsets in the sensor values. Alternatively, however, the offsets could be estimated, thus improving integration during the acceleration phase.

It would also be possible to provide a further integration and to check the positions at various points in the hoisting rope system, for example using absolute encoders on the hoist drive, on the hoisting winch and/or a deflection pulley of the cable system, for example a deflection pulley on the hook. In particular, a change in position can be determined within a certain period of time, which in itself enables a slack rope detection analogously to a speed comparison.

The present invention is explained in more detail below with reference to preferred exemplary embodiments and associated drawings. In the drawings show:

1: a hoist in the form of a tower crane in a side view, the hoist being shown in normal operation with only a very small angle of inclination of the load-carrying means;

Fig. 2: the hoist from Fig. 1 with the load handling device sitting on the ground and the resulting relatively large angle of inclination of the load handling device and the associated slack rope formation,

3: a front view of the crane or hoist from FIG. 2, which shows a lateral tilting of the load handling device sitting on the ground and the correspondingly large angle of inclination, and

4: a side view of the hoist from the previous figures, in which a slack rope is set between the hoist winch and the deflection roller due to a fixed deflection roller, although the load handling device is not seated on the ground.

As the figures show, the hoist 1 can be designed, for example, as a tower crane and can comprise a jib 14 along which a trolley 2 can be moved, from which a hoist cable 3 runs. In the case of a tower crane, said jib 14 can sit on a tower, with the tower or the jib being rotatable about an upright axis relative to the tower, for example by means of a slewing gear. It is understood that the hoist but also in the form of another type of crane, such as a telescopic boom crane with a boom that can be luffed up and down, or in the form of a derrick crane, a maritime crane, a loading crane or another type of hoist.

The hoist rope 3 can be wound up and unwound by a hoist winch 10 and thus tightened and lowered, with a hoist winch drive 11 driving the hoist winch 10 and being able to be controlled by a control device 7 of the hoist 1 .

The hoist rope 3 carries a load handling device 15, which can include, for example, a load hook, but also a lifting magnet or sling ropes. Regardless of this, the hoist rope 3 can be reeved on the load handling device 15, which can have a bottom block 4 for this purpose, see FIG .

In order to be able to detect a slack rope formation in the area of the hoist rope 3 , the hoist 1 can have a determination device 16 which can be part of the control device 7 . Irrespective of this, the determination device 16, like the control device 7, can be designed to work electronically, for example having a microprocessor and a program memory in order to be able to process a determination program stored in the memory with appropriate algorithms.

In this case, the determination device 16 receives sensor signals, which can be evaluated for the presence of specific characteristics by evaluation means 17 of the determination device 16, which can be embodied, for example, in the form of software program means.

The determination device 16 can receive signals from an inclination sensor 18, which can detect or determine an inclination angle a of the load handling device 15 relative to the vertical and/or relative to a natural static alignment of the load receiving device, cf Said inclination sensor system 18 comprises at least one inclination sensor element, which can be attached to the load-carrying means 15 in order to follow the tilting or inclination of the load-carrying means 15 and experience it yourself.

In particular, said inclination sensor system 18 can have a so-called IMU 5, i.e. an inertial measuring device on load-carrying means 15, which provides acceleration and yaw-rate signals that characterize or reflect the acceleration and yaw-rates on load-carrying means 15.

Said inclination sensor system 18, in particular said IMU 5, is advantageously designed to detect inclinations and/or tilting and/or rotational speeds and/or accelerations about at least one horizontal axis of rotation, preferably about two horizontal axes of rotation perpendicular to one another. Two-axis inclination and/or yaw rate and/or yaw acceleration detection can be used to detect, in particular, a lateral tilting of load handling device 15, as shown in Fig. 3, and also a forward or backward pitching of load handling device 15, as shown in Fig 2 shows. In particular, the inclination sensor system 18 can detect at least a tilting about a tilting axis parallel to the deflection axis of the bottom block 4 and a tilting about a lying axis perpendicular thereto.

Advantageously, the yaw rates can also be detected in three axes. Translational accelerations can also be recorded in three axes. Said IMU 5 can advantageously detect translational accelerations with respect to three axes and also yaw rates or rotational accelerations with respect to three axes.

In normal hoist operation, as shown in Figure 1, the majority of the gravitational acceleration g acts in the Z direction, see Figure 1, so that the angle a of the load handling device 15 relative to the vertical is usually zero or very small. The hoist rope 3 usually swings only a few degrees relative to the vertical len, so that the angle of inclination of the lifting device 15 is correspondingly small.

However, if the load handling device 15 touches the ground, as shown in FIGS. 2 and 3 , the orientation of the load handling device 15 changes significantly. The angle of inclination a relative to the vertical becomes relatively large and also changes very quickly when the bottom block 4 touches the ground 9 .

If the inclination sensor system 18 detects such an inclination angle a that exceeds a predetermined limit value and/or a tipping speed and/or acceleration that exceeds a specific limit value for the tipping speed or the tipping acceleration, which can be determined by the named evaluation means 17 by comparison , the determination device 16 can assume that slack rope is forming and emit a corresponding slack rope signal.

If such a slack rope signal is present, the control device 7 can switch off the hoist drive 11 and, if necessary, also switch off other hoist drives 8, such as a slewing gear drive or a luffing drive for the boom 14, in order to prevent the load handling device 15 from being lowered further or the load handling device 15 to drag over the ground to prevent.

Advantageously, the control device 7 can block all hoist movements when the determination 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 lift-up movement of the hoist drive 11.

The control device 7 can be configured to block the other hoist drives 8 until the hoist rope 3 is tensioned again by the hoist-up movement or the slack rope is eliminated, which is caused, for example, by a decrease or drop in the angle of inclination a due to the Inclination sensors 18 can be determined. For example, if the angle of inclination a falls below one predetermined limit value, which coincides with the aforementioned first limit value, but can also deviate from it, for example be smaller, it is assumed by the determination device 16 that there is no longer any slack rope, whereupon the control device 7 can release the hoist drives 8 again.

By blocking further hoist drives, the lower block 4 can be prevented from rubbing on the ground 9, which means that further damage from snagging pebbles or sand can be avoided.

Advantageously, the determination device can also receive signals from a load or cable force sensor system 19 which provides a load signal which characterizes the cable force acting in the hoisting cable 3 . For example, the aforementioned load sensor system 19 can have a load sensor 6 or a cable pull sensor which can, for example, detect the cable force of the hoist cable 3 at the attachment point of the hoist cable 3, see FIGS. Alternatively or in addition to such a rope force sensor 6 at the attachment point of the hoist rope 3, the load sensor system 19 can also have a load measuring axis on the bottom block 4 and/or have load measuring axes on other deflection rollers 12, by means of which cable pull forces or corresponding reaction forces on the deflection rollers can be determined .

If the load signal from the load sensor system 19, which characterizes the cable pull, falls below a predetermined limit value or if the drop rate of said load signal exceeds a predetermined limit value, the determination device 16 can assume the formation of slack cable. The specified limit value for the load signal can take into account the mass of the load-carrying device 15 including the bottom block 4, since when the load-carrying device 15 is suspended, at least the weight of the load-carrying device 15 always pulls on the hoist rope, so that if the load signal drops to a lower value, it can be assumed that that the load handling device 15 rests on the base 9. 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 tilting speed, the load signal also falls below a predetermined limit value and/or the rate of fall of the load signal is required to rise above a predetermined limit value before the determination device 16 provides the slack rope signal. If necessary, the limit values mentioned can also be dynamically adjusted, as explained at the beginning, in order, for example, to output a slack rope signal even if the signals from the inclination sensor system 18 and the load sensor system 19 do not yet reach the respective limit value, but both do to be close.

As Fig. 4 illustrates, slack rope can form not only when the load handling device 15 is resting on the ground 9, but also when the hoisting rope 3 is blocked between the hoist winch 10 and the load handling device 15, for example by a frozen deflection roller 13, See FIG. With proper operation, a predetermined hoist winch or drum acceleration, taking into account the lever arm that changes due to multi-layer winding, induces a specific acceleration of the hoist rope 3 in the area of the hoist winch 10, which then entails a corresponding acceleration at the load handling device 15 that is proportionally changed due to the reeving brings. If these accelerations deviate from one another or if they do not correspond to the ratio corresponding to the deflection and reeving geometry, it can be assumed that slack rope formation has occurred.

An acceleration sensor system 20 can preferably detect the above-mentioned accelerations on the hoist winch 10 or the hoist drive 11 on the one hand and on the load bearing detection means 15 on the other hand, for example by 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, which can detect the acceleration in the upright direction, can be attached to the load handling device 15 . This can be the IMU 5 mentioned, for example, which provides corresponding acceleration signals.

The acceleration on the hoist winch 10 and the acceleration on the load handling device 15 are compared with one another by the evaluation device 17, with the transmission or reduction ratio being able to be taken into account by the reeving. If the accelerations deviate from one another by a predetermined amount or by a tolerance limit value, the determination 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 lifting drive 11 or only allow lifting movements.

Claims

Claims Lifting gear with a hoist rope (3) on which a load handling device (15) is provided for picking up and lifting a load, and a determination device (16) for determining slack rope on the hoist rope (3), characterized in that the named determination device (16 ) has an inclination sensor system (18) for detecting an inclination and/or a tipping speed and/or a tipping acceleration of the load handling device (15) and provides a slack rope signal when the detected inclination and/or tipping speed and/or tipping acceleration of the load handling device (15) exceeds a predetermined one exceeds the limit. Hoist according to the preceding claim, wherein the inclination sensor (18) is designed to detect at least inclinations and/or tilting speeds and/or tilting accelerations with respect to a horizontal tilting axis, the inclination sensor (18) preferably being designed to work on two or three axes. Hoist according to one of the preceding claims, wherein the inclination sensor system (18) has at least one sensor element fastened to the load-receiving means (15). Hoist according to one of the preceding claims, wherein the inclination sensor system (18) has an inertial measuring device (5) for providing acceleration and yaw rate signals to the load-receiving means (15). Hoist according to one of the preceding claims or the preamble of claim 1, wherein the determination device (16) has a load sensor system (19) for detecting the load pulling on the hoisting cable and/or for detecting a hoisting cable force and is designed to provide a slack cable signal if the detected load and/or detected hoisting cable force falls below a predetermined limit value and/or a drop rate of the detected load and/or hoisting cable force exceeds a predetermined limit value. Hoist according to the preceding claim, wherein the determination device (16) is designed to only provide the slack rope signal if, in addition to reaching a limit value for the inclination and/or tilting speed and/or tilting acceleration of the load handling device (15), the limit value for the detected load and/or hoisting cable force is reached, the determination device (16) being configured, if necessary, to take into account adapted limit values for the inclination and load signals in the linked consideration of the signals from the inclination sensor system (18) and the load sensor system (19). Hoist according to one of the two preceding claims, in which the load sensor system (19) has a tensile force and/or load sensor (6) at an attachment point of the hoist cable (3). Hoist according to one of the two preceding claims, wherein the load sensor (19) has a load measuring axis on a bottom block (4) of the load means (15) or on another deflection roller (12) of the hoist cable drive. Hoist according to one of the preceding claims or the preamble of claim 1, wherein the determination device (16) has an acceleration sensor (20) for detecting an acceleration on a hoist winch (10) and/or a hoist drive (11) for the hoist cable (3) and for Detecting an acceleration on the load handling device (15) and is designed to provide a slack rope signal when the two detected accelerations differ from each other by a predetermined amount. Hoist according to the preceding claim, wherein the acceleration sensor system (20) on the hoist winch (10) and/or the hoist drive (11) comprises a yaw rate sensor and, if necessary, a winding position sensor, and on the load handling device (15) an acceleration sensor for detecting upright accelerations, in particular a Inertial measuring device (5) has. Hoist according to one of the two preceding claims, wherein the determination device (16) is designed to take into account a proportionality factor corresponding to the course of the hoisting rope, in particular a reeving of the hoisting rope, when comparing the two detected accelerations. Hoist according to one of the preceding claims, wherein determination means are provided for determining an acceleration of the load handling device and/or the load from a load signal from a/the load sensor system (19) using the relationship F = m * a, in particular from the changes in the load signal. Hoist according to one of the preceding claims, wherein a control device (7) is provided for automatically switching off and/or blocking a hoist drive (11) and/or other hoist drives (8) when the said slack rope signal is present. Hoist according to the preceding claim, wherein said control device (7) is designed to only allow hoist movements that tension the hoist rope, in particular a lift-up movement of a hoist drive (11) and/or a luffing-up movement of a boom (14), when the slack rope signal is present. Hoist according to one of the preceding claims, wherein the determination device (16) has a wireless communication interface for wirelessly receiving sensor signals. Method for determining slack rope on a hoist (1), which is provided with a hoist rope (3) and a load handling device (15) attached thereto for picking up and lifting a load, characterized in that an inclination and/or or a tipping speed and/or a tipping acceleration of the load handling device (15) is detected and a slack rope signal is provided when the recorded inclination and/or tipping speed and/or tipping acceleration of the load handling device (15) exceeds a predetermined limit value. Method according to the preceding claim, in which a load tugging on the hoisting rope and/or a hoisting rope force is detected by means of a load sensor (19) and a slack rope signal is provided if the detected load and/or detected hoisting cable force falls below a predetermined limit value and/or a rate of fall of the detected load and/or hoist cable force exceeds a predetermined limit value, and/or an acceleration sensor system (20), on the one hand, an acceleration on a hoist winch (10) and/or a hoist drive (11) for the hoist cable (3) and, on the other hand, an acceleration on the load handling device (15 ) is detected and a slack rope signal is provided if the two detected accelerations deviate from each other by more than a predetermined amount.