Lifting device for a crane

Abstract

A lifting device (1, 1') for a crane comprising a load-handling device (2) for receiving a crane load (5), a lifting device (3) for raising and lowering the load-handling device (2), and a lifting device base (4, 4') for attaching the lifting device (3) to the crane, wherein the lifting device base (4, 4') comprises a first part (42, 42') with a fastening device (422, 422') for attaching the lifting device base (4, 4') to a crane and a second part (44, 44') on which the lifting device (3) engages, as well as an articulating device (46), wherein the two parts (42, 44) are connected to each other by means of the articulating device (46) such that the second part (44, 44') is tiltably held on the first part (42, 42'), characterized in that at least one stabilizer (48, 48', 48'') is arranged between the first part (42, 42') and the second part (44, 44'), which provides an essentially horizontal equilibrium position of the second part (44, 44') of the hoist base (4, 48'') without crane load (5).4') specifies, wherein the at least one stabilizer (48, 48', 48'') comprises a pre-tensioned spring and / or a shock absorber and / or a gas spring and / or an oil brake cylinder, and the lifting device (3) is designed as a tension member arrangement (3) with at least three tension members (32, 32', 32''), wherein the tension members (32, 32', 32'') engage the lifting device base (4, 4') at horizontal intervals and run obliquely towards each other towards the load-bearing device (2).

Description

The invention relates to a lifting mechanism for a crane comprising a load-handling device for receiving a crane load, a lifting device for raising and lowering the load-handling device, and a lifting mechanism base for attaching the lifting device to the crane. Suspension cables are commonly used for lifting and lowering loads. While they are very strong in the longitudinal or tensile direction, they offer no stabilization across the longitudinal axis. Suspended loads therefore tend to swing or oscillate, requiring considerable experience and caution to avoid becoming dangerous. A particularly hazardous situation regularly arises in daily practice when people attempt to manually hold suspended loads to suppress oscillations or even to restrain swinging loads to stop the oscillation. Other examples include overhead cranes with a crossbeam that travels along the length of a building and a trolley with a hoist that also travels along the crossbeam. This allows loads to be lifted anywhere in the building, moved as needed, and lowered again at the desired position. Other well-known cranes feature a boom that rotates around a base, with the hoist located at the end of the boom or on a trolley that travels along the boom. Lateral loads, which can lead to oscillations of suspended loads, occur particularly during crane operation and are based on unavoidable inertial and acceleration forces. It is also not always possible to lift loads perfectly horizontally, for example, if the load cannot be attached vertically above its center of gravity or if the hoist is not positioned vertically above the load attachment point. When lifting the load, tilting moments can occur, which can also lead to oscillations of the load once it is freely suspended. DE 20 2018 101 068 U1 discloses an electric balancing hoist in which at least one elastic element is integrated into the power train. The elastic element enables limited manual movement of the load without immediate activation of the motor and optionally also serves to detect the weight force via appropriate sensors. DE 11 92 381 A describes a transport device for open or closed containers with a holding device that enables safe and tip-proof transport on a conveyor track. The device comprises a guide rail and positive-locking holding elements, which ensures the stability of the container even when moving over inclines and declines. DE 10 2009 034 121 A1 relates to a device for singulating and precisely aligning workpieces, in particular cylindrical objects. The device comprises an inclined conveyor plane and at least one contact edge for rotation and singulation, whereby workpieces can be fed in the correct orientation to a downstream processing unit. Based on this state of the art, the invention aims to avoid and / or dampen vibrations of moving crane loads. This problem is solved according to the invention by a lifting mechanism for a crane comprising a load-handling device for receiving a crane load, a lifting device for raising and lowering the load-handling device, and a lifting mechanism base for attaching the lifting device to a crane, the lifting mechanism base being further developed in that the lifting mechanism base comprises a first part with a fastening device for attaching the lifting mechanism base to a crane and a second part on which the lifting device engages, as well as an articulating device, wherein the two parts are connected to each other by means of the articulating device in such a way that the second part is tiltably mounted on the first part, wherein at least one stabilizer is arranged between the first part and the second part, which provides a substantially horizontal equilibrium position of the second part of the lifting mechanism base when there is no crane load.wherein at least one stabilizer comprises a pre-tensioned spring and / or a shock absorber and / or a gas spring and / or an oil brake cylinder and the lifting device is designed as a tension member arrangement with at least three tension members, wherein the tension members engage at the base of the lifting mechanism at horizontal intervals and run obliquely towards each other towards the load-bearing device. The invention particularly ensures that pendulum movements of the crane load or the lifting device are absorbed by a tilting movement of the two parts of the lifting base relative to each other. It is advantageous if the lifting device and its attachment to the second part of the lifting mechanism base are designed to be so rigid that a lateral force acting on the load-bearing device is at least partially transmitted via the lifting device as a tilting moment to the second part of the lifting mechanism base. Various lifting devices can be designed for this purpose within the scope of the invention. For example, telescopic lifting devices can be designed to be correspondingly rigid and attached to the lifting mechanism base. Advantageously, the joint device is designed to be torsionally rigid in order to prevent the two parts of the hoist base from twisting relative to each other. This ensures that, according to the invention, the parts of the hoist base tilt relative to each other under oscillating crane loads and do not deflect uncontrollably even in unforeseen load cases. To minimize loads perpendicular to the pendulum direction of the crane load, the joint device is preferably designed in such a way that tilting of the two parts of the hoist base relative to each other in any direction is possible. Preferably, the articulated device is also designed to have a constant length. This means that, in particular, the distance between the first and second parts of the hoist base, and thus the overall length of the hoist, remains essentially independent of the crane load or the pulling load for a given length of the traction cables. To counteract any oscillation of the tilting motion between the first and second part of the hoist base, at least one stabilizer is arranged between the first and second part, which, without crane load, provides an essentially horizontal equilibrium position for the second part of the hoist base. In particular, the invention provides that the joint device is designed as a stabilizer. It is provided that the at least one stabilizer comprises a pre-tensioned spring and / or a shock absorber and / or a gas spring and / or an oil brake cylinder. To prevent lateral movement of at least one stabilizer, it is also conceivable that the stabilizer is designed to be resistant to lateral deflection. For this purpose, for example, a guide rod can be provided, which is preferably arranged longitudinally axially to the spring, shock absorber, gas spring, or hydraulic brake cylinder of the stabilizer. It is provided that the lifting device is designed as a tension member arrangement with at least three tension members, wherein the tension members engage horizontally spaced apart from each other at the base of the lifting device and run obliquely towards each other towards the load-bearing device. Due to the arrangement of the at least three tension strands according to the invention, the tension directions of the individual tension strands run transversely to the tension or lifting direction of the lifting device as a whole, which is designed as a tension strand arrangement, so that mutual stabilization of the tension strands transversely to the lifting direction is achieved. Pendulum movements of the crane load can thus be significantly reduced. Another advantage of the invention is that an inventive embodiment of a tension member arrangement has a certain torsional stability and thereby counteracts unwanted rotational movements of a suspended load around the vertical axis. Furthermore, the invention is suitable for a wide variety of traction cords, allowing them to be flexibly selected and adapted to the specific application. For example, but not limited to, the traction cords within the scope of the invention can be designed as cable pulleys, wire rope pulleys, webbing pulleys, or chain pulleys. For an even load distribution on the tension strands, it is advantageous if the at least three tension strands are arranged at regular intervals from each other. In the embodiment of the invention with at least three tension members, it is further advantageous if at least three stabilizers are arranged between the first and second parts. In this way, the articulated device in particular absorbs the load forces, while the stabilizers counteract transverse or oblique forces without completely preventing a tilting movement of the second part of the lifting mechanism base. Advantageously, each stabilizer is assigned to one of the tension members by arranging the tension member, the joint, and the stabilizer assigned to that tension member in a straight line. The tension member and stabilizer can be located on the same or opposite sides of the joint. In some embodiments of the invention, a single actuator is provided which is operatively connected to all tension strands for adjusting the length of the tension strand assembly. This ensures, particularly due to the design, a synchronous change in the length of the tension strands, thus eliminating the need for, for example, a complex control system for adjusting the length of the individual tension strands. Alternatively, each haul rope can be assigned a separate actuator for length adjustment, which allows for smaller individual actuators. Furthermore, separate actuators make it possible to compensate for unintentional length differences between the individual haul ropes. This also makes it possible to dynamically dampen any vibrations of the crane load by controlling the length adjustment of only one or some of the haul ropes. In a first embodiment of the invention, the first part of the hoist base is arranged above the second part of the hoist base, with the fastening device being designed, in particular, for suspended mounting on a crane. This embodiment is especially suitable, for example, for retrofitting the invention, by easily replacing an existing hoist of a crane with a hoist according to the invention without any modifications to the crane itself. An alternative embodiment of the invention is characterized in that the first part of the lifting mechanism base is arranged below the second part of the lifting mechanism base. The first part is preferably designed for surface or upright mounting on a crane. This advantageously ensures that the height between the ground and the crane can be optimally utilized as lifting height without the design-related height of the lifting mechanism base reducing the effective lifting height. The invention is explained in more detail below with reference to an embodiment of the invention, which is illustrated in the drawings. Fig. 1 schematically shows a side view of an exemplary lifting device according to the invention; Fig. 2 schematically shows a perspective view of the lifting device according to the invention from Fig. 1; Fig. 3 schematically shows a perspective view of the lifting device according to the invention from Fig. 1 under an inclined load; and Fig. 4 schematically shows a perspective view of another exemplary lifting device according to the invention under an inclined load. The exemplary lifting devices 1, 1' shown in the drawings according to the invention each comprise a load-bearing device 2 for receiving a crane load 5, which is suspended from a lifting device base 4, 4' by means of a lifting device 3 designed as a tension member arrangement 3. In a first embodiment of the invention, illustrated in Figures 1, 2 to 3, the lifting mechanism base 4 comprises a first part 42 and a second part 44, each of which, by way of example, includes a torsionally rigid metal plate. Alternative embodiments, for example using frame constructions, are also conceivable within the scope of the invention. The first part 42 has on its upper side a fastening device 422 for suspending the lifting mechanism 1 on a crane, for example on a trolley movable along a crane boom or crane crossbeam. The second part 44 is arranged below the first part 42 and carries three pull cords 32, 32', 32'' designed as chain hoists, each of which is adjustable in length via a separate actuator 34, 34', 34''. Alternative designs are also conceivable within the scope of the invention. In particular, cable hoists, preferably wire rope hoists, can be used instead of chain hoists and / or the separate actuators 34, 34', 34'' can be replaced by a common actuator. The tension strands 32, 32', 32'' are spaced apart from each other on the second part 44. To optimize the balancing of the forces, the tension strands 32, 32', 32'' are evenly distributed, so that they are arranged, in particular, at the corners of an imaginary equilateral triangle. Starting from the second part 44, the tension strands 32, 32', 32'' run obliquely towards each other in the direction of the crane hook 2, so that their distance from each other at the crane hook 2 is significantly smaller than at the hoist base 4 or its second part 44. The second part 44 of the hoist base 4 is pivotably connected to the first part 42 by means of a hinge connection 46. The hinge connection 46 is designed such that the second part 44 can tilt relative to the first part 42 in any direction. Simultaneously, the hinge connection 46 absorbs the load forces from the dead weight of the hoist 1 and the suspended crane load 5 and is preferably designed to be of constant length. In this context, this means in particular that the hinge connection 46 is not stretched or lengthened by loads 5 suspended from the crane hook 2. Specifically, the joint device 46 can comprise a universal joint or cardan joint. This design ensures the degrees of freedom provided for in the invention for tilting the second part 44 relative to the first part 42 and simultaneously represents a length-constant construction method. Furthermore, it effectively prevents the first part 42 and the second part 44 from twisting against each other unintentionally. The relative position of the first part 42 and the second part 44 of the hoist base 4 is determined by means of three stabilizers 48, 48', 48'' such that the second part 44 assumes a substantially horizontal equilibrium position when the hoist 1 according to the invention is attached as intended to a crane (not shown in the drawings). The stabilizers 48, 48', 48'' each have, for example, a compression spring 48, 48', 48'' and may include further components not shown within the scope of the invention, such as lateral guides for the springs 48, 48', 48'' and / or damping elements in addition to or instead of the springs 48, 48', 48''. If the hoist 1 according to the invention is loaded transversely to the horizontal as shown in Fig. 3, the arrangement of the tension cords 32, 32', 32'' according to the invention provides mutual stabilization, so that the tension cord arrangement 3 as a whole exhibits a certain lateral stiffness. Thus, a difficult-to-dampe oscillation of the crane load 5 on one tension cord 32, 32', 32'' does not occur. Instead, the second part 44 of the hoist base 4 tilts relative to the first part 42. While this also corresponds to a pendulum or oscillation movement of the crane load 5, it is easily controlled and damped by means of the stabilizers 48, 48', 48''. A second embodiment of the invention is shown in Fig. 4. The lifting mechanism 1' according to the invention is again shown under lateral load. A significant difference from the lifting mechanism 1 according to the invention described above in Figs. 1, 2 to 3 lies in the lifting mechanism base 4'. In the alternative hoist base 4', the first part 42' for attaching the hoist base 4' to a crane is arranged below the second part 44', to which the tension cords 32, 32', 32'' are attached. The fastening device 422' of the first part 42' of the hoist base 4' is preferably designed to attach the hoist base 4', which rests on or stands on a crane, to the crane. Despite the height of the hoist base 4', the tension cords 32, 32', 32'' are attached above the crane, so that the entire height between the crane and the ground can be optimally utilized as lifting height. The arrangement of the traction strands 32, 32', 32'' on the second part 44' of the hoist base 4' is chosen in particular such that the traction strands 32, 32', 32'' pass laterally by the first part 42' of the hoist base 4' and the crane and are not obstructed by these components. REFERENCE MARK 1, 1' Hoist 2 Load-handling device 3 Lifting device 32, 32', 32" Chain hoist 34, 34', 34" Actuator 4, 4' Hoist base 42, 42' First part 422, 422' Fastening device 44, 44' Second part 46 Articulated joint 48, 48', 48" Compression spring 5 Crane load

Claims

A lifting device (1, 1') for a crane comprising a load-handling device (2) for receiving a crane load (5), a lifting device (3) for raising and lowering the load-handling device (2), and a lifting device base (4, 4') for attaching the lifting device (3) to the crane, wherein the lifting device base (4, 4') comprises a first part (42, 42') with a fastening device (422, 422') for attaching the lifting device base (4, 4') to a crane and a second part (44, 44') on which the lifting device (3) engages, as well as an articulating device (46), wherein the two parts (42, 44) are connected to each other by means of the articulating device (46) such that the second part (44, 44') is tiltably held on the first part (42, 42'), characterized in that at least one stabilizer (48, 48', 48'') is arranged between the first part (42, 42') and the second part (44, 44'), which provides an essentially horizontal equilibrium position of the second part (44, 44') of the hoist base (4, 48'') without crane load (5).4') specifies, wherein the at least one stabilizer (48, 48', 48'') comprises a pre-tensioned spring and / or a shock absorber and / or a gas spring and / or an oil brake cylinder, and the lifting device (3) is designed as a tension member arrangement (3) with at least three tension members (32, 32', 32''), wherein the tension members (32, 32', 32'') engage the lifting device base (4, 4') at horizontal intervals and run obliquely towards each other towards the load-bearing device (2). Lifting device (1,1') according to claim 1, characterized in that the lifting device (3) and the attachment of the lifting device (3) to the second part (44, 44') are designed to be so rigid that a transverse force acting on the load-bearing device (2) is at least partially transmitted via the lifting device (3) as a tilting moment to the second part (44, 44') of the lifting device base (4, 4'). Lifting device (1, 1') according to claim 1 or 2, characterized in that the joint device (46) is designed to be torsionally rigid in order to prevent the two parts (42, 44; 42', 44') of the lifting device base (4, 4') from twisting against each other. Lifting device (1, 1') according to one of claims 1 to 3, characterized in that the joint device (46) is designed such that tilting of the two parts (42, 44; 42', 44') of the lifting device base (4, 4') relative to each other in any direction is possible. Lifting device (1, 1') according to claim 1, characterized in that at least three stabilizers (48, 48', 48'') are arranged between the first part (42, 42') and the second part (44, 44'), wherein in particular one stabilizer (48, 48', 48'') is assigned to each of the traction strands (32, 32', 32'') by arranging each of the traction strands (32, 32', 32''), the joint device (46) and the stabilizer (48, 48', 48'') assigned to the respective traction strand (32, 32', 32'') in a straight line. Hoisting device (1,1') according to one of claims 1 to 4, characterized in that the first part (42, 42') of the hoisting device base (4, 4') is arranged above the second part (44, 44') of the hoisting device base (4, 4'), wherein the fastening device (422, 422') is designed in particular for suspended attachment to a crane. Lifting device (1, 1') according to one of claims 1 to 4, characterized in that the first part (42, 42') of the lifting device base (4, 4') is arranged below the second part (44, 44') of the lifting device base (4, 4'), wherein the fastening device (422, 422') is designed in particular for surface or upright fastening to a crane.

Images