CRANE

Description

[0001] The present invention relates to a crane, for example in the form of a tower crane, with a crane boom from which a load-handling device such as a load hook can be raised and lowered via a lifting rope.

[0002] With large cranes such as tower cranes or telescopic jib cranes, loads are often lifted, lowered, or maneuvered into a specific position at a relatively great distance from the crane operator's cab, making the load hook and the load attached to it difficult to see from the cab. The operator's cab of a tower crane may be located at the top of the tower or directly below the jib, while on other crane types, such as telescopic jib cranes, it may be located on the superstructure. The relatively large distance to the load hook and the attached load results from the relatively long reach of the jib, as well as the height of the jib and the relatively deep lowering depth of the load hook. The hoist rope may, for example, run from the jib via a trolley that travels along the jib, or it may run directly from the jib tip.

[0003] To be closer to the load hook or the load to be attached, the crane operator can, if necessary, control the crane movements using a remote control to improve visibility of the load hook while operating the crane. Alternatively, the crane operator can work with a spotter who is positioned near the lifting or setting-down point on the construction site to see the load hook and communicate its position or provide operating instructions to the crane operator, for example, via two-way radio, mobile phone, and / or hand signals. If no spotter is available, or if the two-way radio connection or visibility is poor or intermittent, precise positioning of the load hook relative to the load to be lifted or the load relative to the setting-down point is not reliably possible.

[0004] The crane operator typically receives information from the crane's sensors about the lowering depth of the load hook, indicating the depth of the hook below the boom. However, for various reasons, this cannot replace the information and instructions of the spotter or the operator's own visual contact when precisely maneuvering the load hook and the attached load into position. Firstly, the lowering depth alone is of little use if the ground is uneven or if the height of the lifting or lowering surface, or its difference in level from the crane's setup location, is unknown. Secondly, the loads themselves are often attached to the load hook via slings or chains of unspecified length. Furthermore, the load's dimensions may vary or be unknown.This means that the crane operator does not know the exact distance between the load hook and the end of the load, nor the distance from the end of the load to objects below or to the ground, and can only roughly estimate these distances. Working in shafts or behind blind spots also presents a difficulty, as visibility is either poor or nonexistent.

[0005] For the reasons mentioned, a spotter is almost always required at the loading or unloading location. However, if such a spotter is not available, or if the connection to the two-way radio or mobile phone is poor or intermittent, or even just the visibility is poor, it becomes difficult to safely maneuver and precisely lower or retrieve the lifting hook and the load attached to it.

[0006] Therefore, load hook positioning devices have already been proposed that provide the crane operator with more precise information about the exact position of the load hook. For example, DE 20 2019 102 393 U1 describes a tower crane with several electromagnetic radio modules attached to the boom and the load hook, from whose radio signals an electronic evaluation unit determines the position of the load hook. WO 2005 / 082770 A1 also discloses a tower crane with a downward-facing camera mounted on its trolley to display a video image of the load hook's surroundings to the crane operator, enabling the operator to better identify obstacles in the direction of travel. Similar video assistance systems are also known from DE 197 25 315 C2, JP 9-142773, and EP 29 31 649 B1. Even though these assistance systems make it easier for the crane operator to move the load hook or the load attached to it in a horizontal direction, respectively,While positioning the load hook more precisely in the horizontal plane remains difficult for the crane operator to control its lowering depth appropriately and accurately in order to achieve a smooth lowering and jerk-free lifting of the load (see also CN 113148879 A and EP 3915928 A1). EP3915928A1 discloses the preamble of claim 1.

[0007] In contrast, the present invention is based on the objective of creating an improved crane of the aforementioned type that avoids the disadvantages of the prior art and advantageously develops the latter further. In particular, it should enable precise and appropriate control of the lowering depth of the load hook, even without a spotter at the lifting or placement location, in order to achieve a smooth lowering and lifting of a load.

[0008] According to the invention, the aforementioned problem is solved by a crane according to claim 1. Preferred embodiments of the invention are the subject of the dependent claims.

[0009] It is therefore proposed to determine the height of the load-handling device above the ground or above a surface below it automatically or semi-automatically and to provide the crane control system or crane operator with this height information. According to the invention, a detection device is mounted on the load-handling device to detect the distance of the load-handling device from the ground and / or from an object located below the load-handling device. Unlike conventional lowering depth indicators, the measurement is not taken—or not only measured—from the load-handling device upwards to the crane boom, but rather the downward distance is determined from the load-handling device to the ground or an object located below it. This allows for accurate determination even with unknown slings such as unspecified chains, unknown dimensions, or other unknown components.Even without a spotter, appropriate maneuvering movements of the load-handling device can be precisely controlled to allow for smooth lowering and jerk-free lifting of the load, regardless of the load's height or the unobstructed and unknown elevation of the placement or pickup point. In particular, there is no need to calculate backwards from the lowering depth, including any necessary estimation of the elevation difference between the crane's setup location and the placement or pickup point, to determine the exact vertical distance of the load-handling device from the relevant contour beneath it.

[0010] According to the invention, the detection device comprises an optical sensor with a downward-facing detection axis for distance measurement. Such optical detection not only allows for precise distance measurement of the load-handling device to the ground or to an object located beneath the load-handling device, but can also be used to provide the crane operator with visual information about the contours of the load being lifted and / or the surrounding environment.

[0011] Such optical sensors can, for example, include a laser measuring head on the load-handling device, which can determine the distance of the load-handling device to the ground or to an object located under the load-handling device using a laser measuring beam directed downwards towards the ground.

[0012] According to the invention, the optical sensor system comprises an imaging sensor that looks downwards from the load-handling device and provides an image of the object or the ground located below the load-handling device, similar to a top view. The distance can be determined from the signals of the imaging sensor system by means of an image evaluation device.

[0013] The imaging sensor system described above is stereoscopic or stereo-optical and comprises two spaced-apart, downward-facing optical sensors and / or cameras. These sensors and / or cameras, positioned at two different points and thus with two slightly different lines of sight, provide two images of the area below the load-handling device. Due to the offset in the lines of sight of the two optical sensors or cameras, the image processing unit can determine the distance of the contour or surface point corresponding to the pixel or image point from the load-handling device, based on contours and / or pixels and / or image points identified in the images.

[0014] A major advantage of optical sensors like cameras is their lack of drift, ensuring consistent distance measurement accuracy even over extended periods. Furthermore, they don't just capture a single point in the environment, but rather map a large area. This offers a significant advantage over other sensor systems, as only two sensors or cameras can cover a large area. Additionally, such a stereo-optical sensor system allows for the three-dimensional capture of an object located beneath the load-bearing device, enabling the determination of the relative 3D position of a captured object.

[0015] Image analysis can be performed in various ways. For example, the image analysis device can include a triangulation module designed to calculate the depth distance between the sensor or camera plane and the object or ground from the known distance between the two optical sensors or cameras and the parallax or displacement of corresponding points between the images.

[0016] The two sensors or cameras of the stereoscopic sensor system can advantageously be mounted spaced apart from each other in a horizontal plane in the area of ​​the load-handling device or arranged at the same height level near the load-handling device in order to look down at the ground or an object located under the load-handling device from at least approximately the same height.

[0017] Advantageously, the imaging sensors or cameras can be arranged on opposite sides of the load-handling device and / or have viewing or detection axes that are arranged in an upright direction on different sides of the load-handling device.

[0018] In an advantageous embodiment of the invention, the sensors can be mounted on a lower block to which the lifting rope is attached and to which the load-handling device, for example in the form of a load hook, is fastened. Such a lower block typically assumes a predetermined orientation that allows the sensors or cameras mounted on it to look downwards.

[0019] For example, a sensor carrier can be attached to the lower block, extending approximately coaxially to the axis of rotation of the lower block's pulley and / or projecting outwards from the lower block on opposite sides, allowing the sensors or cameras to be mounted facing downwards on opposite sides of the lower block. This carrier can optionally be telescopic, retractable, and / or foldable to allow it to be positioned in a stowed position without projecting and in a projecting working position. In the latter position, the two sensors or cameras are separated by a predetermined distance, which can form the baseline of the stereoscopic system.

[0020] In a further development of the invention, the evaluation unit, which analyzes the signals from the optical sensors and determines the distance of the load-handling device to the ground or an object below, can be attached or mounted together with the sensors in the area of ​​the load hook, thus enabling signal evaluation without time delay due to longer transmission paths. Alternatively, it would also be possible to attach the evaluation unit, or at least a sub-module of the evaluation unit, to another crane structural component, such as the boom, a tower, or generally a slewing platform or undercarriage, and to evaluate the signals transmitted there by the sensors in order to determine the distance of the load-handling device from the ground or an object contour below.

[0021] The aforementioned detection device on the load-handling attachment and any other components located there, such as the aforementioned image evaluation device, can be powered by a battery and / or a rechargeable battery, or more generally by an energy storage device. In particular, a signal or data transmission device, by means of which the sensor signals and / or the already evaluated distance or height information can be transmitted to a crane control system, can also be powered by the energy storage device.

[0022] The aforementioned signal and / or data transmission device may advantageously be designed to operate wirelessly, for example by having a radio module.

[0023] Alternatively or additionally to an energy storage device on the load-handling device, electrical energy can also be generated directly on the load-handling device, in particular on an associated lower block for deflecting the lifting rope. In an advantageous embodiment of the invention, a generator for generating electricity can be arranged on the load-handling device or on an associated lower block, which can be driven by a deflection and / or guide pulley and / or by the lifting rope running around the deflection pulley. For example, the generator can be connected to the deflection pulley via a spur gear or bevel gear stage, or it can have a drive wheel running on the lifting rope.

[0024] The electricity supplied by the generator can be delivered directly to the consumer, i.e., the sensors and / or the evaluation unit and / or the data transmission unit, possibly via power and / or supply and / or control electronics, and / or at least partially fed into an electrical storage device acting as a buffer, from which the stored energy is then supplied to the respective consumer. Such an electrical intermediate storage device can be, for example, a battery or a capacitor, or it can include such components.

[0025] The invention is explained in more detail below with reference to a preferred embodiment and the accompanying drawings. The drawings show: Fig. 1: A side view of a crane according to an advantageous embodiment of the invention, on whose load-handling device a detection device with imaging sensors for detecting the distance of the load-handling device from the ground and / or an object under the load-handling device is provided, Fig. 2: The detection device including the imaging, stereo-optical sensors on the load-handling device of the crane made of Fig. 1 , wherein partial views (a) and (b) show the sensors on the lower bottle from horizontal viewing directions tilted 90° to each other, Fig. 3: a side view of the stereoscopic sensors on the load-handling device and a load located below it, as well as the two detection areas of the two imaging sensors or cameras of the stereo-optical sensors, offset from each other, and Fig. 4: a side view of the stereoscopic sensors similarly Fig. 3 , where, without a load attached to the load-bearing device, the two offset optical detection areas of the two imaging sensors or cameras falling to the ground are shown.

[0026] How Fig. 1 As shown, the crane 20 can, for example, be designed as a tower crane and have a jib 22 which, in the case of a tower crane, can be mounted on a tower 21 and cantilever out from it. A trolley 24 can be moved along the jib 22 by means of a trolley drive, with a hoist rope 23 running from the aforementioned trolley 24 to raise and lower a load-handling device 2 attached to the hoist rope 23, for example in the form of a load hook, and also to move horizontally by means of the trolley 24. In addition, the crane 20 can, for example, be rotated about the vertical axis of the tower by means of a slewing mechanism, so that the jib 22 pivots. Not shown, it would also be possible to raise and lower the jib 22 by means of a luffing mechanism.

[0027] The aforementioned movements of the crane structure and the raising and lowering of the hoist rope 23 allow the load-handling device 2 to be directed and maneuvered as desired. The crane drives, for example, the hoist rope drive, the trolley drive, the slewing drive, and / or the luffing jib drive, can be controlled by a central crane control device 5. The crane control device 5 may include input devices such as joysticks, rotary switches, or other operating buttons, which enable the crane operator to operate the crane drives. Alternatively or additionally, the crane control device 5 may also include an automatic or semi-automatic module to automatically execute predetermined travel paths with the load-handling device 2.

[0028] The aforementioned load-handling device 2 in the form of the load hook can be attached to a lower block 1, on which the lifting rope 23 is reeved, wherein one or more deflection pulleys 25 can be rotatably mounted on the lower block 1 in order to deflect the lifting rope 23, cf. Fig. 2 .

[0029] A detection device 3 is arranged on the load-handling device 2, more precisely on the lower block 1, by means of which the distance c of the load-handling device 2 from the ground and / or the distance d of the load-handling device 2 to the upper edge of a suspended load 26 and / or the distance a of the load-handling device 2 from a lower edge of said load 26 and / or also the distance b of said lower edge of the load 26 from the ground can be determined. The distances a, b, c, d mentioned above refer to the vertical distance and / or the height difference between the load-handling device 2 and the aforementioned contours or also from the lower edge of the load 26 to the ground.

[0030] The aforementioned depth information or distances a, b, c, d can be transmitted to the crane control device 5 for display on a screen or for general output, which can also be done acoustically if necessary. Preferably, however, the distance can be displayed on a screen.

[0031] Alternatively or in addition to displaying the aforementioned depth information or distance information a, b, c, d, the crane control device 5 can also use this height or depth information to automatically control a lowering or lifting process.

[0032] As the figures show, the detection device 3 includes a stereoscopic sensor system 9, which comprises two optical or imaging sensors or cameras 10, 11, which have essentially vertically downward directed detection axes, cf. Fig. 2 The two cameras, 10 and 11, are mounted at essentially the same height.

[0033] How Fig. 2 As shown, the two cameras 10, 11 are arranged perpendicular to their detection axes, so that a baseline 8 is formed between the detection axes of the cameras 10, 11, which defines a predetermined horizontal distance between the cameras 10, 11.

[0034] In In a further advantageous embodiment of the invention, the two cameras 10, 11 can be mounted on the lower block 1, particularly on opposite sides thereof. For example, a sensor carrier 12 can project from the lower block 1 to opposite sides, the sensor carrier 12 extending, for example, approximately coaxially or parallel to the axis of rotation of a deflection pulley 25 on the lower block 1. The cameras 10, 11 can advantageously be arranged on opposite sides, particularly at approximately equal distances from a lifting cable plane defined by the strands of the lifting cable 23, cf. Fig. 2 .

[0035] As the Figuren 3 and 4As shown, the two cameras 10, 11 each have a detection area 13, 14 directed downwards from the load-bearing device 2, which can widen conically downwards from the cameras 10, 11. The two detection areas 13, 14 are arranged or shifted relative to each other according to the baseline 8 or the distance between the two cameras. From this parallax or the known length of the baseline 8, the depth distance in terms of the aforementioned distances a, b, c and / or d can be determined from the images of the cameras 10, 11, more precisely from the displacement of corresponding points between the two images. The image evaluation device 4 provided for this purpose can, for example, have a triangulation module 15 which can calculate the depth in terms of distances a, b, c and / or d from the known baseline 8 and the geometric position of corresponding image points.The aforementioned image evaluation device 10 can, for example, include a computing device comprising a microprocessor, a program memory and / or data memory for storing a software module and / or the signals to be evaluated.

[0036] As the figures show, the aforementioned image evaluation device 4 can advantageously also be attached to the load handling device 2, for example mounted on the lower block 1, in order to determine the depth information a, b, c and / or d from the images of the stereoscopic sensor 9.

[0037] The aforementioned image evaluation device 9 can be supplied with electrical energy from an energy storage device 6, for example in the form of a battery or accumulator.

[0038] Alternatively or additionally, a generator 7 can be provided on the load handling device 2, in particular on the lower block 1, to generate electrical energy from movements of the lifting rope 23 and / or a deflection pulley 25 of the lower block 1, which can be fed into the aforementioned energy storage device 6 or also directly supplied to the image evaluation device 4 and / or the detection device 3, in particular the cameras 10, 11.

[0039] Advantageously, the image evaluation unit 4, and optionally also the detection unit 3, can be connected to a signal and / or data transmission unit 16 in order to transmit the depth information a, b, c and / or d and / or signals from the imaging sensors to the crane control unit 5, preferably wirelessly. The aforementioned data transmission unit 16 can, for example, include a radio module to transmit the aforementioned information wirelessly.

[0040] The data transmission device 16 can advantageously also be supplied with electrical energy from the energy storage device 6 and / or powered from the generator 7.

[0041] The image evaluation device 4 can advantageously determine not only the aforementioned depth information a, b, c and / or d, but also the contours of the load 26 and / or contours on the ground in a plan view, for example the width and / or length of the load 26 in the plan view and / or its horizontal spacing 18 from shaft walls 19, cf. Fig. 3 .

[0042] The depth information a, b, c and / or d determined by the image evaluation unit 4, as well as the aforementioned contour information, for example, in terms of the load width 17 and / or the distance 18 from the ground contour, can be used by the crane control device 5 to control the crane drives in automated operation and / or be provided to the crane operator on a display device, whereby the crane operator can control the crane from the crane operator's cab and / or via remote control and / or teleoperation. Depending on the application, the display device can be located in the crane operator's cab, at the remote control station, or on a radio remote control.

Claims

1. Crane, in particular a rotating tower crane, comprising a crane boom (22), from which a load-receiving means (2), such as a load hook, can be raised and lowered by means of a hoist rope (23), wherein a detection device (3) for detecting the height (A, B, C, D) of the load-receiving means (2) above the ground and / or above an object (26) located beneath the load-receiving means (2) is provided on the load-receiving means (2), characterized in that the detection device (3) comprises a stereo-optical sensor system (9) having two optical sensors and / or cameras (10, 11) spaced apart from one another and each directed downwardly toward the ground, with two approximately parallel detection axes (27, 28) which are spaced apart from one another by a baseline (8), and with two mutually overlapping detection regions (13, 14), and that an image evaluation device (4) is provided and configured to evaluate the optical signals and / or images of the stereo-optical sensor system (9) and to determine, from said optical signals and / or images, the height of the load-receiving means (2) above the ground or above the object located beneath the load-receiving means.

2. Crane according to the preceding claim, wherein the image evaluation device (4) comprises a triangulation module (15) for determining said distance (A, B, C, D) by triangulation on the basis of the known spacing (8) of the sensors and / or cameras (10, 11) from one another and on the basis of corresponding image points.

3. Crane according to one of the preceding claims, wherein the detection device (3) is mounted on a lower block (1) on which the hoist rope (23) is reeved and to which the load-receiving means (2) is fastened.

4. Crane according to one of the preceding claims, wherein the detection device (3) comprises a sensor carrier (12) which protrudes from the load-receiving means (2) and / or the lower block (1) toward opposite sides.

5. Crane according to one of the preceding claims, wherein the two optical sensors and / or cameras (10, 11) of the stereo-optical sensor system (9) are arranged on opposite sides of the load-receiving means (2), in particular at substantially the same height levels.

6. Crane according to one of the preceding claims, wherein the image evaluation device (4), together with the optical sensor system (9), is mounted on the load-receiving means (2) and / or on the lower block (1) connected thereto.

7. Crane according to one of the preceding claims, wherein the detection device (3) comprises a wireless data transmission device (16) for transmitting the determined distance information and / or the sensor signals of the optical sensor system (9) to a central crane control device (5), wherein said data transmission device (16) is arranged on the load-receiving means (2) and / or on the lower block (1) connected thereto.

8. Crane according to one of the preceding claims, wherein an energy storage device (6) for supplying the detection device (3) with electrical energy is provided on the load-receiving means (2).

9. Crane according to one of the preceding claims, wherein the load-receiving means (2) and / or the lower block (1) connected thereto comprises a generator (7) for generating electrical energy from a movement of the hoist rope (23) and / or from a movement of a deflection pulley (25) deflecting the hoist rope (23).

10. Crane according to one of the preceding claims, wherein the detection device (3) is configured to detect contour information in a plan view, in particular a width (17) of a suspended load (26) and / or a horizontal spacing (18) of a suspended load (26) from a ground contour, and to provide said information as plan-view information.