Lifting systems and lifting methods for cranes

Abstract

To generate pre-tension of a hoist rope during movement of a suspension element of a crane.SOLUTION: A lift system includes a separable pre-tension hook block and an auxiliary rope which is connected to the pre-tension hook block, can be wound around and rewound from an auxiliary winch mountable on a crane, and is guided by a deflection device mountable on a boom of the crane. The pre-tension hook block includes two hook block parts, which can be mutually locked to be releasable and are connected to each other through the auxiliary rope. An upper hook block part includes means for fixing a suspension element of the crane. A lower hook block part has pickup means for fixing a weight. The present invention further relates to a pre-tension hook block of the lift system, a crane including the lift system, and a method of lifting the suspension element of the crane by the lift system.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a lifting system for generating hoist rope pretension during movement of a suspension element of a crane, particularly for a mobile crane or a crawler crane, to a crane comprising such a lifting system, to a pretension hook block, and to a method for lifting a suspension element of a crane using such a lifting system.

Background Art

[0002] In most cranes, the lifting and hoisting of a load is performed via a hoist rope that carries the load via a suspension element (usually a hook block having a lift hook), the hoist rope being guided in the crane boom via deflection means and being supported by a hoist winch in a wound-up and rewoundable manner. In this regard, the hoist rope is usually supported by the hoist winch in a plurality of layers. To avoid "twisting" during the winding-up process, the hoist rope has to be wound as tightly as possible on the lower layer at the hoist winch. In a normal lifting process, most of the hoist rope is rewound during the load pick-up and is wound up on the hoist winch during the lifting process. In this respect, the load generates the necessary pretension in the wound-up hoist rope and is wound up tightly enough on the hoist winch.

[0003] When a dismantling process (e.g., the dismantling of a chimney or a wind turbine) is carried out by a crane, the load often has to be picked up at a high altitude and placed on the ground. For this purpose, the hook block is wound up "empty", i.e., without a load, and the load is subsequently picked up at height and then placed on the ground.

[0004] This means that the lower layer of the hoist rope is pre-tensioned only by the weight of the hook block during hoisting against the hoist winch, and the load is picked up only at the top layer of the winch. In such a disassembly process, the risk of rope tangling and therefore rope damage in a worn state is therefore very high.

[0005] To circumvent this challenge, the hook block weight is now increased, in the simplest case, for example, by using a larger lift hook and / or additional weights. Furthermore, where possible, the hook block winding can be selected to be as small as possible, and switching to parallel operation with two winches can be done. The length of the hoist rope unwound from the winch drum is reduced by these means, and the pretension on the hoist rope is simultaneously increased by the smaller winding with the same weight of the hook block. However, the use of a heavy hook block results in a reduction of the crane's maximum possible working load.

[0006] Furthermore, prior art has shown the possibility of lifting additional weights along with the otherwise empty lift hook and placing them on a structure or similar object. This has the same effect as increasing the weight of the hook block, but has the advantage that no additional weight remains on the hook block during the actual load stroke from the height to the ground, and therefore the available payload is not reduced. The disadvantage here is that in many cases, it is not possible to place or store such additional weights on a structure or similar object at the load pickup point.

[0007] A pretension winch, known as a further solution option from DE202013006584U1, pulls the lift hook weighted by the crane's ballast weights on the ground and generates additional pretension on the hoist rope. However, this requires the provision of additional auxiliary vehicles at the construction site. [Overview of the project] [Problems that the invention aims to solve]

[0008] Therefore, the fundamental objective of the present invention is to ensure good winding quality when winding a hoist rope onto a hoist winch without requiring the use of additional auxiliary vehicles or the placement of weights at a great height. [Means for solving the problem]

[0009] According to the present invention, this objective is achieved by a lift system having the features of claim 1, by a pretension hook block having the features of claim 11, and by the method according to claim 12. Advantageous embodiments of the present invention are obtained from the dependent claims and the following description.

[0010] Accordingly, a lift system for a crane, particularly for a mobile crane or crawler crane, is proposed to generate hoist rope pretension during the lift of the suspension element of the crane. The lift system according to the present invention comprises a separable pretension hook block and an auxiliary rope connected to the pretension hook block and held in a manner that is retractable and unwindable to an auxiliary winch that is positioned or installed on the crane and guided via a deflection device that is positioned or installed on the boom of the crane. The pretension hook block can be raised and lowered relative to the deflection device by retracting and unwinding the auxiliary rope. According to the present invention, the pretension hook block comprises two hook block portions that are retractably lockable to each other and connected to each other via the auxiliary rope, the upper hook block portion having fixing means for fixing to the suspension element of the crane and the lower hook block portion having pick-up means for fixing or picking up a weight.

[0011] When the upper hook block is connected to the suspension element, the upper hook block can be lowered and raised together with the suspension element. The lower hook block is connected to the weight to provide a pretension force to the hoist rope of the crane that carries the suspension element, thereby ensuring good winding quality in the corresponding hoist winch.

[0012] Due to the separability of the pretension hook block, the two hook block sections can be moved independently of each other, and the weight connected to the lower hook block section does not need to be raised together with the suspension element when the suspension element is raised. The position or movement of the weight connected to the lower hook block section can be precisely and safely controlled, for example, via the crane controller of the crane, by skilled control or adjustment of the auxiliary winch.

[0013] Since the two hook block sections are connected to each other via an auxiliary rope, they can be moved apart or joined together by corresponding control of the auxiliary winch. The weight connected to the lower hook block section can, for example, be placed back on the ground and released from the lower hook block section after the suspension element has been raised to the desired height by corresponding control of the auxiliary winch, and subsequently the lower hook block section can be raised again and joined with the upper hook block section, or optionally locked by winding up the auxiliary rope. Since the pretension hook block is "suspended" by a separate auxiliary rope, the pretension hook block can be released from the suspension element in the raised position and is available for picking up parts to be disassembled.

[0014] Therefore, the lift system according to the present invention makes it possible to apply a pretension force to the hoist rope by using an additional weight when the "empty" suspension element is lifted, thus eliminating the need for external auxiliary devices or vehicles other than the weight, and ensuring good winding quality. The weight that generates the pretension force does not need to be lowered to the raised position, but rather can remain in the ground area. Thus, an easy-to-operate flexible system is provided that can be used for disassembly work to ensure good hoist rope winding quality and requires few additional parts to be brought along.

[0015] In the described solution, the load can be kept close to the ground. This is an improvement in safety. There is always a hazard in the area beneath a suspended load, and this area must be avoided by people.

[0016] In many cranes, such as grid mast cranes (i.e., cranes with grid booms), auxiliary winches with auxiliary ropes and mast noses that can be installed at the boom end are already standard equipment; therefore, in such cases, only the pretension hook block according to the present invention needs to be connected to the auxiliary ropes. This does not occupy much space and can be easily brought onto the crane. Thus, complex crane modifications are not required when using a telescopic crane to use the lift system according to the present invention, which requires separate static observation. The lift system according to the present invention can be easily modified or installed for individual operations using an existing crane and then removed again.

[0017] Where it is stated in this case that an auxiliary winch or hoist winch is being hoisted up or unwinded, or being hoisted up or unwinded, it is therefore meant that the corresponding auxiliary rope or hoist rope being hoisted up or unwinded from the winch, or being hoisted up or unwinded, is expressed in abbreviated form.

[0018] The feature that the upper and lower hook block sections are connected to each other via an auxiliary rope should be given a broad interpretation, and it should be understood that the auxiliary rope extends between these two hook block sections. In particular, the two hook block sections are movable relative to each other.

[0019] In possible embodiments, the upper hook block portion is provided with at least one first deflection pulley, and the lower hook block portion is provided with a second deflection pulley through which the auxiliary rope is guided. This means that the pretension hook block has at least two leaves for the auxiliary rope.

[0020] The leaving of the auxiliary rope can be designed so that its end is fixed to the lower hook block. Thus, the entire three strands are obtained together with a deflection pulley provided in the deflection device for the simplest case, with the lower and upper hook block each having exactly one deflection pulley, the first strand of the auxiliary rope extending between the deflection pulley and the lower hook block, the second strand extending between the lower hook block and the upper hook block, and the third strand extending from the hook block for fixing to the lower hook block. Here, the mass of the suspended weight is distributed proportionally across the different strands of the hook block. In the case of three strands, two strands contribute to increasing the pretension, and about two-thirds of the weight is suspended by the suspension element, tensioning the hoist rope wound on the hoist winch.

[0021] Different configurations, such as more than one deflection pulley per upper and / or lower hook block, are also, of course, conceivable here.

[0022] In further possible embodiments, the pretension hook block preferably includes at least one deflection pulley that causes the auxiliary rope to pass laterally through the suspension element located in the upper hook block portion. Thus, this additional deflection pulley does not function in leaving the auxiliary rope to distribute the weight force of the additional weight, but rather functions solely to guide the passage of the auxiliary rope. However, alternatively, it is conceivable that one of the deflection pulleys is used simultaneously to guide the passage.

[0023] In further possible embodiments, the pretension hook block includes a guide mechanism, which, when coupled, can bring the lower and upper hook block portions into a predetermined locked position. Here, the guide mechanism functions to precisely align the upper and lower hook block portions and / or may allow the two hook block portions to be introduced into each other more simply.

[0024] The guide mechanism preferably includes one or more guide rails. Alternatively or additionally, the guide mechanism may include a tongue-groove mechanism in which a groove can be applied to the lower hook block and a tongue can be applied to the upper hook block. The reverse is also possible. The guide mechanism is preferably designed so that the coupling of the hook block portions occurs automatically in the raised position without the need for manual assistance afterward.

[0025] In further possible embodiments, the lower and upper hook block portions have connecting means for locking them together in a releasable manner. The connecting means preferably allows pin connection of the lower and upper hook block portions by one or more pins.

[0026] In a further possible embodiment, the lower and upper hook block parts can be locked by an operable locking mechanism, which is preferably operable actively or passively when or after the upper and lower hook block parts are joined. Active operation can be effected, for example, by a lock pin controlled electrically or hydraulically. However, passive operation of the locking mechanism is preferably triggered especially when joining the upper and lower hook block parts. Thereby, the pretensioning hook block can have a simple structural design.

[0027] In a further possible embodiment, the locking mechanism is configured to be automatically locked when the lower and upper hook block parts are joined and preferably has a spring element and / or a snap-in mechanism. The snap-in mechanism may include, for example, a pivotable hook element arranged on the upper or lower hook block part, and when joining the respective other hook block part, the hook element is pivoted and the latter snaps back from the upper and lower hook elements by a spring mechanism in the locked position, and the pin engages around the other hook block part, and the two hook block parts are locked to each other. Instead of the hook element and the pin, different elements, for example a displaceable latch, may be used. [[ID=*]]

[0028] Manual pinning during joining may be omitted due to the automatic locking when joining the hook block parts, whereby the lifting procedure is substantially simplified. In addition to an automatically operable locking mechanism, manual pinning may equally be considered.

[0029] In a further possible embodiment, a hoist winch is further provided, the hoist rope connected to the suspension element being supported in a retractable and rewinding manner, and the hoist winch and the auxiliary winch are preferably operable independently of each other, and the suspension element and the pretension hook block are thus liftable independently of each other. The hoist winch and the auxiliary winch are preferably operable by a crane controller.

[0030] In a further possible embodiment, a crane controller is further provided, and the crane controller is configured to synchronously control the hoist winch and the auxiliary winch such that, during movement of the suspension element, by rewinding the auxiliary winch and winding up the hoist winch at the same time, the weight fixed to the pretension hook block of the unlock is suspended and held at a certain height above the ground. The height and / or alignment of the weight can be detected by corresponding sensors, and the measured values can be entered for adjustment.

[0031] Thus, the overall pretensioning procedure can advantageously be carried out and monitored by a crane controller. Thus, the pretensioning process can correspond to two monitored hook operations, a normal crane operation, for example, having a common load, with a hook in the suspension element as a main lift operated by a hoist winch and a hook in the pretension hook block operated by an auxiliary winch. <00001​​​​​​The suspension element may also be the hook block of the crane. Alternatively or additionally, the deflection device may be a mast nose or folding tip that can be installed at the tip of the boom and preferably has at least one deflection pulley through which an auxiliary rope is guided.

[0034] The present invention further relates to a pretension hook block for a lift system according to the present invention. Here, the pretension hook block comprises an auxiliary rope fixing means for fixing the auxiliary rope of the lift system, preferably disposed on the lower hook block portion. To fix the auxiliary rope to the pretension hook block, the auxiliary rope is wound onto the two hook block portions and connected to the auxiliary rope fixing means. Here, the same advantages and characteristics as the lift system according to the present invention are clearly obtained, and further repetition is omitted at this point. Therefore, the above description relating to possible embodiments of the pretension hook block applies as appropriate.

[0035] The present invention further relates to a method for lifting a crane suspension element using a lift system according to the present invention, the method comprising the following steps: securing the pretension hook block to the suspension element; unlocking the upper and lower hook block portions by, for example, removing one or more pins; securing the weight to the lower hook block portion; lifting the suspension element by winding the hoist rope connected to the suspension element onto a hoist winch, thereby moving the lower and upper hook block portions away from each other (i.e., the lower hook block portion remains attached to the weight, while the upper hook block portion is pulled upward together with the suspension element); and placing the weight on the ground after the movement of the suspension element has been performed by unwinding the auxiliary winch while the suspension element is in its raised position and releasing the lower hook block portion from the weight.

[0036] At this point, the same advantages and characteristics as the lift system according to the present invention are clearly obtained, and further explanation is omitted.

[0037] The first three steps can be carried out in any desired order.

[0038] In a possible embodiment of this method, the lower hook block is raised by winding up the auxiliary winch and, after the weight is lowered and released, is coupled with the upper hook block, the hook blocks can be locked together, and the locked pretension hook block is preferably subsequently released from the suspension element and placed on the ground by unwinding the auxiliary winch. Here, the suspension element may be connected to, for example, a part to be disassembled at a great height, and the part may be lowered to the ground. This method may be subsequently repeated, and sufficient pretension force is available for the hoist rope with each movement of the "empty" suspension element.

[0039] Accessibility for unhooking the pretension hook block from the suspension element can be assumed to be given, since the load to be disassembled must remain attached to the suspension element in the subsequent state.

[0040] In a further possible embodiment of this method, the hoist winch and the auxiliary winch are controlled synchronously or in a synchronized manner, particularly by the crane controller of the crane, for the lifting of the suspension element, and the weight is held, particularly suspended, at a certain height above the ground by unwinding the auxiliary winch and simultaneously winding up the hoist winch.

[0041] In a further possible embodiment of this method, the movement of the suspension element is performed by the operation of two hooks monitored by the crane controller, and the automatic adjustment of the hoist and auxiliary winch is preferably performed by the crane controller so that the weight is held at a predetermined height and / or a specific location above the ground.

[0042] The use of the system according to the present invention, as previously presented, can be obtained from claim 16.

[0043] Further features, details, and advantages of the present invention can be obtained from embodiments described below with reference to the drawings. [Brief explanation of the drawing]

[0044] [Figure 1] Figure 1 shows a schematic side view of the pretension hook block according to the present invention in a locked state, suspended from the lift hook of a crane according to one embodiment. [Figure 2] Figure 2 shows the pretension hook block related to Figure 1 with weights applied in the unlocked state. [Figure 3] Figure 3 shows a longitudinal cross-sectional view of the pretension hook block according to the present invention. [Figure 4] Figure 4 shows a schematic side view of the boom tip of a crane equipped with suspension elements, a mast nose, and a pretension hook block. [Figure 5] Figure 5 shows a side view and a front view of the pretension hook block according to the present invention. [Figure 6] Figure 6 shows a schematic representation of the connection areas of the upper and lower hook block portions of the pretension hook block according to one embodiment of the present invention. [Figure 7] Figure 7 shows a side view of the superstructure of a crane according to one embodiment, indicating the position of the hoist winch. [Figure 8]Figures 8 to 11 show the different positions of the suspension element and the pretension hook block in the overall side view of the crane during the implementation of the lift method according to one embodiment of the present invention in each case. [Figure 9] Figures 8 to 11 show the different positions of the suspension element and the pretension hook block in the overall side view of the crane during the implementation of the lift method according to one embodiment of the present invention in each case. [Figure 10] Figures 8 to 11 show the different positions of the suspension element and the pretension hook block in the overall side view of the crane during the implementation of the lift method according to one embodiment of the present invention in each case. [Figure 11] Figures 8 to 11 show the different positions of the suspension element and the pretension hook block in the overall side view of the crane during the implementation of the lift method according to one embodiment of the present invention in each case. [Modes for carrying out the invention]

[0045] Figure 1 shows a schematic side view of a pretension hook block 10 of the lift system according to the present invention in a preferred embodiment. The pretension hook block 10 is suspended from a suspension element 6 of a crane 1 (here, a crawler crane 1 in the embodiment shown herein).

[0046] The crane 1, shown in the overall side view in Figures 8-11, comprises a lower traveling body 8 having a crawler unit, an upper structure 3 rotatably supported on the lower traveling body 8 around a vertical axis, a boom 2 articulatedly connected to the upper structure 3 so as to be swivelable around a horizontal axis, and a suspension element 6 for lifting a load, designed as a roller frame 6a having a lift hook 6b in the embodiment shown herein.

[0047] The superstructure 3 of crane 1 is shown separately in the side view of Figure 7. A hoist winch 5, on which a hoist rope 4 is supported so as to be retractable and untractable, is located on the superstructure 3. The hoist rope 4 is connected to a suspension element 6, which can be raised and lowered by operating the hoist winch or by retracting and unwinding the hoist rope 4.

[0048] The crane 1 further includes a hoist winch 14 on which a hoist rope 12 is supported so as to be able to be retracted and untracted. As can be seen from Figure 8, the auxiliary winch 14 is located in the area below the boom 2.

[0049] As shown in Figure 4, the hoist rope 4 is guided to the hoist winch at the boom tip via a deflection pulley on the roller head. A deflection device 16, which is configured as a mast nose and has a deflection pulley through which the auxiliary rope 12 is guided, is installed at the boom tip.

[0050] Figures 1 to 3, which show the pretension hook block 10 according to the present invention in the locked state (Figure 1) and the unlocked state (Figures 1 to 2), are referred to below. Figure 5 further shows a side view and a front view of the pretension hook block.

[0051] The pretension hook block 10 according to the present invention is designed in two parts, including an upper hook block section 20 (upper block) and a lower hook block section 22 (lower block). A fixing means 21 to which the pretension hook block 10 can be tied or fixed to the lift hook 6b of the crane 1 is located above the upper hook block section 20. A further lift hook-shaped pickup means 23 to which a load or weight 40 can be fixed is located below the hook block section 22.

[0052] The two hook block sections 20, 22 can be locked together so that the pretension hook block 10 as a whole can move or rise (see Figure 1). The locking may be performed by one or more pins 30. As can be seen particularly in Figure 3, the upper hook block section 20 has a first deflection pulley 24, and the lower hook block section 22 has a second deflection pulley 26. The auxiliary rope 12, guided by the mast nose 16, starts from the mast nose 16 and is guided or hooked onto the second deflection pulley 26 of the lower hook block section 22, and then onto the first deflection pulley 24 of the upper hook block section 20, and is connected to the lower hook block section 22 via fixing means 29. The upper hook block section 20 further has an additional deflection pulley 28 to allow the auxiliary rope 12 to pass laterally through the suspension element 6. The two hook block sections 20 and 22 are connected to each other via an auxiliary rope 12 such that the distance between the two hook block sections 20 and 22 is variable by appropriate control of the auxiliary winch 14.

[0053] Sufficiently large pretension for the lift of the suspension elements can be generated in the hoist rope 4 by the pretension hook block 10 according to the present invention, which is a combination of an auxiliary winch 14, an auxiliary rope 12, and a mast nose 16, and the hoist rope 4 is tightly wound around the hoist winch 5. This prevents tangling and ensures good winding quality.

[0054] When the suspension element 6 is lifted by the crane 1 without a load attached for the purpose of dismantling components at a higher elevation, the weight 40 is fixed to the pickup means 23 of the lower hook block portion 22 of the pretension hook block 10 fixed to the suspension element 6, as shown in Figure 2. The weight 40 is connected to the suspension element 6 and, by extension, the hoist rope 4 via the pretension hook block 10, generating an appropriate pretension force.

[0055] The pulley block of the pretension hook block 10, implemented via deflection pulleys 24, 26 and fixing means 29, has the effect of spreading the weight force of the weight 40 fixed to the pickup means 23 across the various strands of the hoist rope 12. Since the leaving of the auxiliary rope 12 of the pretension hook block 10 is selected from three leavings having a first strand leading to the mast nose 16, two strands contribute to the increase in pretension, i.e., about two-thirds of the ballast weight is suspended from the suspension element 6 and tensions the hoist rope 4 wound onto the hoist winch 5. Here, three or more leavings of the hoist rope 12 or one or more each deflection pulley 24, 26 can, of course, be provided on the hook block sections 20, 22.

[0056] The two deflection pulleys 24 and 26 have parallel axes of rotation. The fixing means 29 is positioned above the second deflection pulley 26 in the lower hook block section 22, and the pickup means 23 is positioned below the second deflection pulley 26. A further deflection pulley 28 is positioned diagonally above the first deflection pulley 24 in the upper hook block section 20, and the fixing means 21 is positioned above the first deflection pulley 24.

[0057] As can be seen from Figure 4, the distance between the first deflection pulley 24 and the further deflection pulley 28 can substantially correspond to the distance between the corresponding deflection pulleys for the hoist rope 4 and auxiliary rope 12 at the boom head or mast nose 16.

[0058] As can be seen in Figure 5, the two hook block portions 20 and 22 can be pressed against each other, and the upper hook block portion 20 has a pickup region 34 configured as a tongue for the pickup region of the lower hook block portion 22, which is configured as a groove 32. The pickup regions 32 and 34 can be chamfered, thereby facilitating threading or pressing.

[0059] As described above, the two hook block sections 20, 22 can be manually locked via the pin 30 (see also Figure 5). An alternative embodiment is schematically shown in Figure 6, in which the pretension hook block 10 has a locking mechanism. Thus, the retaining pin 38 is located in the upper region of the lower hook block section 22, and the swivelable hook element 36 is located in the lower region of the upper hook block section 20. When the two hook block sections 20, 22 are coupled, the pin 38 automatically pushes the hook 36 laterally, as shown, causing it to swivel around its pivot axis. When the hook block sections 20, 22 reach their fully retracted licking positions, the hook 36 snaps, automatically locking the two hook block sections 20, 22. For this purpose of pushing the hook 36 into its locked position, a spring element (not shown in more detail) may be provided. This eliminates the need for manual locking of the hook block sections 20, 22 and facilitates coupling, especially at high heights.

[0060] Figures 8-11 show an overall side view of the crane 1 during the movement of the suspension element 6 according to an embodiment of the method according to the present invention. In this regard, the process begins with a situation in which the load is to be lifted from a raised position and placed on the ground 9 for dismantling. In order to lift the suspension element 6 to the height of the load to be lifted with sufficient pretension, the previously lowered suspension element 6 is connected to the weight 40 via a pretension hook block 10 in the first step. The pretension hook block 10 is suspended from the lift hook 6b in a locked state. The weight 40 is fixed to the receiving means 23 of the pretension hook block 10. While suspended from the lift hook 6b, the pretension hook block 10 is already connected to an auxiliary rope 12, or, for example, during the first movement, the auxiliary rope 12 is led to the pretension hook block 10 after its suspension.

[0061] Here, the pretension hook block 10 is unlocked or unpinned, and the weight 40 is slightly raised by the operation of the hoist winch 5 and the auxiliary winch 14 (see Figure 8). Here, the weight 40 can be raised off the ground. The weight 40 can be held in close to the ground 9, preferably by corresponding control and monitoring of the crane controller, by unwinding the auxiliary winch 14 and simultaneously winding up the hoist winch 6 while the suspension element 6 is being raised. In particular, the weight 40 can be suspended. As long as the weight 40 is suspended, high pretension is applied to the hoist rope 4 or the hoist winch 5 due to the weight.

[0062] When the suspension element 6 is fully lifted, i.e., to the desired height, via the hoist rope 4 by the hoist winch 5 (see Figure 9), the auxiliary winch 14 is rewound, the lower hook block section 10 is lowered, and the weight 40 is unhooked and placed on the ground 9.

[0063] The lower hook section 22 is then lifted by winding up the auxiliary winch 14 and guided to the upper hook block section 20. When the hook block sections 20 and 22 are in their locked positions, they can be pinned together (or automatically locked as described above). This may be done from an elevated position where the load to be transported or lowered must also be lifted. Figure 10 shows the situation after the hook block sections 20 and 22 have been joined and locked together while the pretension hook block 22 of the pretension hook block 10 is still suspended from the suspension element 6.

[0064] Here, the pretension hook block 10 can be unlocked from the suspension element 6 of the crane 1 (see Figure 11) and subsequently lowered to the ground 9 by the auxiliary winch 14. Here, the suspension element 6 is still in the raised position and can be connected to the load to be transported. The load can be placed to the ground 9 by operating the hoist winch 5. The steps described above can be repeated for the next movement of the suspension element 6.

[0065] A weight 40 that is raised from the ground 9 and whose entire pretension process can be monitored by the controller of the crane 1 is advantageous in this method. The pretension process corresponds to normal crane operation. In this case, it is a monitored two-hook operation having a hook 6b as the main movement on the main or hoist winch 5 and a hook 23 on the auxiliary winch 14 via the mast nose 16 containing a common load.

[0066] In this solution, conversion work on crane 1, which requires separate static observation, is not necessary. Furthermore, an auxiliary vehicle does not need to be used for the application of pretension. An auxiliary winch 14 and a short mast nose 16 for auxiliary movement form part of a standard setup that also has many grid mast cranes and large telescopic cranes. Moreover, crane 1 may rotate and / or move during the pretension process, which is not possible in solutions with an auxiliary vehicle and / or auxiliary winch placed on the ground. [Explanation of Symbols]

[0067] 1 Crane 2 Boom 3 Superstructure 4 Hoist rope 5 Hoist winches 6 Suspension Elements 6a Pulley Block 6b Lift Hook 8 Lower running body 9 ground 10 Pretension Hook Blocks 12. Auxiliary rope 14. Auxiliary winch 16. Deflection device (mast nose) 20 Upper hook block section 21 Fixing means 22 Lower hook block section 23. Pickup method (lift hook) 24. First deflection pulley 26. Second deflection pulley 28 Deflection pulley 29 Auxiliary fixing means 30 pins 32 Grooves 34 Tang 36 hooks 38 pins 40 weights

Claims

1. A lift system for a crane (1) for generating hoist rope pretension during the movement of the suspension element (6) of the crane (1), A detachable pretension hook block (10), The system includes an auxiliary rope (12) which is connected to the pretension hook block (10) and supported in a manner that allows it to be wound up and unwound by an auxiliary winch (14) which is positioned or installed on the crane (1), and is guided via a deflection device (16) which is positioned or installed on the boom (2) of the crane (1), The pretension hook block (10) comprises two hook block sections (20, 22) that are lockable to each other in a releasable manner and connected to each other via the auxiliary rope, the upper hook block section (20) having a fixing means (21) for fixing to the suspension element (6), and the lower hook block section (22) having a pickup means (23) for fixing a weight (40), in a lift system.

2. The lift system according to claim 1, wherein the upper hook block portion (20) has at least one first deflection pulley (24), and the lower hook block portion (22) has at least one second deflection pulley (26) through which the auxiliary rope (12) is guided.

3. The lift system according to claim 1, wherein the pretension hook block (10) includes at least one deflection pulley (28) that causes the auxiliary rope (12) to pass laterally through the suspension element (6) located on the upper hook block portion (20).

4. The lift system according to claim 1, wherein the pretension hook block (10) includes a guide mechanism, and the lower and upper hook block portions (20, 22) are guided to a predetermined locked position by the guide mechanism when coupled, and the guide mechanism includes one or more guide rails and / or tongue groove mechanisms (32, 34).

5. The lift system according to claim 1, wherein the lower and upper hook block portions (20, 22) have connecting means for locking them together so as to be releasable, and the lower and upper hook block portions (20, 22) can be pinned by one or more pins (30).

6. The lift system according to claim 1, wherein the lower and upper hook block portions (20, 22) are lockable by an operable locking mechanism (36, 38), and the locking mechanism (36, 38) is operable actively or passively when the hook block portions (20, 22) are coupled or afterward.

7. The locking mechanism is configured to automatically lock when the lower and upper hook block portions (20, 22) are coupled, and the lift system according to claim 6 has a spring element and / or a snap-in mechanism (36, 38).

8. The lift system according to claim 1, further comprising a hoist winch (5) on which a hoist rope (4) connected to the suspension element (6) is supported in a manner that allows it to be retracted and untracted, wherein the hoist winch (5) and the auxiliary winch (14) are operable independently of each other, and the suspension element (6) and the pretension hook block (10) are therefore liftable independently of each other.

9. The lift system according to claim 8, further comprising a crane controller, the crane controller configured to synchronously control the hoist winch (5) and the auxiliary winch (14) so ​​that the weight (40) fixed to the unlocked pretension hook block (10) is suspended and held at a certain height or area above the ground (9) during the movement of the suspension element (6) by unwinding the auxiliary winch (14) and simultaneously winding up the hoist winch (5).

10. A crane (1) comprising a lift system according to any one of claims 1 to 9, wherein the suspension element (6) is a hook block, and / or the deflection device (16) is a mast nose that can be installed at the tip of the boom, and / or the auxiliary winch (14) is located on the superstructure (3) of the crane (1).

11. A pretension hook block (10) of a lift system according to any one of claims 1 to 9, comprising an auxiliary rope fixing means (29) for fixing the auxiliary rope (12) positioned on the lower hook block portion (22).

12. A method for lifting the suspension element (6) of the crane (1) using the lift system described in any one of claims 1 to 9, comprising the following steps: The pretension hook block (10) is fixed to the lowered suspension element (6). The upper and lower hook block sections (20, 22) are unlocked. The weight (40) is fixed to the lower hook block portion (22). By winding the hoist rope (4) connected to the suspension element (6) onto the hoist winch (5), the suspension element (6) is lifted, causing the lower and upper hook block sections (20, 22) to move away from each other. A method for lowering the weight (40) by unwinding the auxiliary winch (14) while the suspension element (6) is in its raised position, and releasing the lower hook block portion (22) from the weight (40).

13. The method according to claim 12, wherein the lower hook block portion (22) is raised by winding up the auxiliary winch (14), and after the weight (40) is lowered and released, it is coupled with the upper hook block portion (20), the hook block portions (20, 22) are locked together, and the locked pretension hook block (10) is subsequently released from the suspension element (6) and placed on the ground (9) by unwinding the auxiliary winch (14).

14. The method according to claim 12, wherein the hoist winch (5) and the auxiliary winch (14) are controlled synchronously or in asynchronously by the crane controller of the crane (1) for the movement of the suspension element (6), and the weight (40) is held at a certain height above the ground (9) by unwinding the auxiliary winch (14) and simultaneously winding up the hoist winch (5).

15. The method according to claim 14, wherein the movement of the suspension element (6) is performed by operating two hooks monitored by the crane controller, and the automatic adjustment of the hoist winch (5) and auxiliary winch (14) is performed by the crane controller so that the weight (40) is held at a predetermined height and / or a specific location above the ground (9).

16. A use of the lift system according to any one of claims 1 to 9, comprising the following steps: The pretension hook block (10) is fixed to the lowered suspension element (6). The upper and lower hook block sections (20, 22) are unlocked. The weight (40) is fixed to the lower hook block portion (22). By winding the hoist rope (4) connected to the suspension element (6) onto the hoist winch (5), the suspension element (6) is lifted, causing the lower and upper hook block sections (20, 22) to move away from each other. A method of simultaneously rewinding the auxiliary winch (14) such that the weight (40) remains on the ground and a certain strand tension exists in the auxiliary winch rope.

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