Abstract:
The present invention relates to a crane having a load hook directly/indirectly fastened to the crane hoist rope and having a frame suspended at the load hook for taking up a special load, in particular for taking up a rotor blade of a wind turbine, wherein the control element(s) of a frame suspended at the load hook is/are guided along a guider rope region of the crane hoist rope.

Description:
The invention relates to a crane having a load hook fastened directly/indirectly to the crane hoist rope and having a frame suspended at the load hook for taking up a special load, in particular for taking up a rotor blade of a wind turbine. 
     BACKGROUND OF THE INVENTION 
     On assembling wind turbines, the rotor blades have to be attached at a large lifting height. Mobile cranes or crawler cranes are preferably used for this purpose. The rotor blade to be mounted has a large rotor surface and consequently a large exposed surface for the wind. To mount the rotor blade at the corresponding wind turbine, a sufficiently precise adjustment and stabilization of the taken-up rotor blade at the mounting height is required. 
     It is already known from the prior art for this purpose to take up the rotor blade by means of a blade. The latter is suspended at the load hook of the hoist rope and takes up the rotor component to be mounted in the corresponding mount. 
     It is, for example, proposed in DE 2006 015 189 U1 to fasten rotor blades via two control ropes at the two guy ropes of the Y-guying system of the main boom and to secure them against rotation. A disadvantage of the proposed solution is that the guy ropes run far away from the longitudinal axis of the main boom. The forces in the horizontally extending control ropes consequently substantially influence the guying forces of the Y-guying system and reduce the payload of the crane. 
     Constructions are furthermore known in which one or more additional ropes, also called guide ropes, is/are tensioned by means of at least one additional winch starting from the boom foot to the boom head. The mount for the rotor blade is connected via two control ropes to the tensioned rope or ropes. 
     The decisive disadvantage of these solutions now comprises the fact that additional winches and rope arrangements are absolutely necessary. The additional equipment articles mean, however, a disadvantageous weight increase of the crane and simultaneously an increasing production cost effort and servicing effort. Furthermore, it is necessary in solutions using two additional ropes to tension both ropes independently of one another. The tensioning force introduced per rope loads the boom since the resulting pressure load acts as an additional load on the boom. The attachment of two independent ropes likewise induces an additional lateral load on the boom if one rope is loaded more. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is now to provide an improved guidance possibility for the control elements of a frame which can be realized comparatively simply and inexpensively. 
     This object is achieved by a crane having the features herein. Advantageous embodiments of the invention are also the subject matter herein. 
     The crane in accordance with the invention includes a load hook which can be fastened directly/indirectly to the crane hoist rope and to which a frame for mounting a special load is fastened. The frame is in particular suitable for taking up a rotor blade of a wind turbine. 
     Such frames are also called “yokes” in technical language. This is a frame which takes up the actual load in a gentle and damage-free manner. The connection between the toad hook and the frame is expediently established via suspension means. To align and stabilize the yoke, it has independently working assemblies such as winches, drives, operating means, etc. 
     The frame used has at least two control elements indirect communication with the crane boom for adjusting, stabilizing and finely aligning the frame or the load taken up. In accordance with the invention, it is now provided that the at least two control elements are guided along a guide rope region of the crane hoist rope. A region of the hoist rope used is accordingly created which provides a guidance possibility for the connected control elements. The attachment of a separate guide rope is consequently superfluous. Separate winches haying a corresponding hydraulic and electric control to tension the separate guide rope or ropes are likewise superfluous. The proposed solution considerably simplifies the crane production and is furthermore substantially less expensive than known designs. 
     The technical performance of the invention is independent of the type of main boom used. It can, for example, be either a lattice mast boom or a telescopic boom. 
     A partial region of the hoist rope is preferably used as a guide rope region which extends parallel to the longitudinal boom axis at the boom side facing the load. It can be expedient for this purpose that the hoist rope is guided from the crane hook back to the boom and is tensioned parallel to the longitudinal boom axis in the direction of the boom foot. The region of the hoist rope guided back is advantageously used as a guide rope region. 
     In a particularly advantageous embodiment of the crane, the guide rope region of the hoist rope is formed by the hoist rope which is guided back from the hock-type block via at least one pulley block at the boom in the direction of the longitudinal boom axis to the lower crane attachment point. At least one pulley block is furthermore expediently arranged at the roller head of the boom tip. One or more pulley blocks can preferably be provided at any desired point of the boom. For example at the main boom, at the boom extension or at the needle. For example the hub height of a wind turbine to be installed can be decisive. 
     At least one deflection pulley is advantageously installable or installed at a variable height at the crane boom in the guide rope region of the hoist rope. The mounting of the pulley block can take place, for example, in coordination with the target hoist height of the load to be achieved. The pulley is preferably bolted to the crane or is fastened to the crane by means of clamping means. 
     One or more control elements are particularly preferably configured as control ropes. Accordingly, at least two control ropes of the suspended frame are guided along the guide rope region of the hoist rope. The use of a control chain and/or of a spindle and/or of a cylinder and/or of a telescopic rod and/or of an articulated link is generally conceivable. The use of an element based on a scissors mechanism is furthermore also conceivable. The design is expediently identical for at least some of the control elements; however, any desired combination of the proposed embodiments is also possible. 
     The end-side attachment point of the hoist rope guided back is preferably at the pivot connection piece of the crane boom. The hoist rope can selectively be attached at the end side to the luffing ram or also to the revolving deck. 
     Provision can advantageously be made that a rope clamp is arranged at the hoist rope end. The hoist rope end can be attachable or attached to any desired point of the crane via the rope clamp depending on the specification profile. 
     The handling of the hoist rope end preferably takes place with the aid of an installation rope which is arranged at the end side at the hoist rope or rope clamp and which is either accessible from the footprint of the crane or alternatively via a drive. It is conceivable to operate the installation rope, in particular to wind it up or unwind it, by means of at least one winch. An already present installation rope of the reeving winch can be used as the installation rope, for example. 
     In an advantageous embodiment of the invention, at least one pulley block arranged in the guide rope region of the hoist rope includes an apparatus for intercepting or fixing at least one guided control element. The control elements slide, in particular by means of a fastened connection link, along the guide rope region of the guide rope in dependence on the hoisting height. The apparatus serves for fixing and stabilizing the control elements, in particular the connection link, so that a precise control or fine adjustment of the frame can be ensured with the aid of the control elements. 
     The pulley block is in particular arranged at the crane such that the control elements or the connection link can be intercepted or fixed at the target hoist height of the taken up load to be reached. A pulley block designed variably installable at the boom preferably has the apparatus for intercepting and fixing. The installation of the pulley block takes place, for example, in the hub height region of a wind turbine to be installed. The attachment of the named pulley block just below the hoisting height to be achieved so that a premature interception and fixing of the control elements results in a specific and advantageous oblique pull of the control elements is particularly advantageous. The oblique pull boosts the achieved fixing of the control elements. 
     The apparatus of the pulley block advantageously comprises at least one plate which is pivotably supported about the pulley block axis and which has at least one abutment surface. The pivotable support of the plate ensures a targeted alignment of the abutment surface in dependence on the rope redirected by the pulley block. 
     The abutment surface is in particular arranged at the lower side of the plate and the rope is guided through the abutment surface orthogonally thereto. The rope particularly preferably runs orthogonally through the surface center of the abutment surface. The vertical movement of the control elements sliding on the rope can consequently be limited to a maximum height by the abutment surface. 
     The plate of the apparatus preferably includes at least one holding roller which ensures a soft and damped positioning of the plate at the rope. This is in particular advantageous if the plate is deflected in any desired direction, which consequently results in an increase in the rope looping angle of the redirected rope at the pulley block. The pulling force arising in the rope acts as a restoring force and is taken up in damped form by the plate due to the holding roller. 
     A connection link is advantageously provided which is suitable for connecting at least one control element to the guide rope region of the hoist rope. The connection link preferably has at least one abutment surface which can be brought into abutment with the suitable counter-abutment surface of the pulley block described above. A fixing/stabilizing of the connection link at the pulley block is achieved by the targeted abutment between the connection link and the pulley block. 
     At least one slide block is preferably provided in the region of the abutment surface of the connection link. A targeted abutment of the two abutment surfaces is ensured with the aid of the slide block. The slide block furthermore effects an improved shape matching between the pulley block and the connection link in the intercepted position of the connection link. 
     The connection link is preferably configured rotatably about the rope axis of the hoist rope so that the movability of the control elements is not restricted or is only slightly restricted. In the intercepted state of the connection link, the slide block preferably slides about the surface periphery of the abutment surface of the pulley block. 
     The invention furthermore relates to a pulley block having an apparatus for intercepting and fixing at least one control element or one connection link respectively. The pulley block obviously has the same features and properties as the preceding embodiment of the crane so that a repeated discussion will be dispensed with at this point. 
     The invention further relates to a connection link which can be intercepted or fixed at the pulley block with a corresponding apparatus. The connection link obviously has the same features and properties as the preceding embodiment of the crane so that a repeated discussion will be dispensed with at this point. 
     It is worthy of mention in this connection that the pulley block and the connection link can naturally also be used at a separate guide rope, not to be associated with the hoist rope, of any desired crane. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further advantages and particulars of the invention will be explained in detail with reference to an embodiment shown in the figures. There are shown: 
         FIG. 1 : a side view of the crane in accordance with the invention with a taken-up rotor blade of a wind turbine; 
         FIG. 2 : a detail representation of the roller head in accordance with  FIG. 1 ; 
         FIG. 3 : a schematic diagram of the pulley block in accordance with the invention for intercepting the connection block in a perspective view; and 
         FIG. 4 : a sectional representation of the apparatus of  FIG. 3  with an intercepted connection link. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows a crane structure  10  for the installation of wind turbines  100 . The specific embodiment of the crane structure  10 , in particular of the boom system  11 , is not significant for the invention. The idea in accordance with the invention can generally be used with any type of boom systems  11  such as with a lattice mast crane as well as a telescopic crane. 
     A yoke  30  is suspended via the suspension means  21  at the load hook  20 . The yoke  30  includes a frame which takes up a rotor blade  101  of the wind turbine  100  to be raised in a gentle and damage-free manner. The yoke  30  furthermore includes a series of independently working assemblies, such as winches, drives, operating means, which serve inter alia for actuating the outgoing control ropes  40 . 
     The control ropes  40  are directly connected to the boom system  11  for the adjustment and stabilization of the yoke  30 . In contrast to the prior art, no additional guide rope is spanned at the boom system  11  as a guide possibility of the control rope  40 . To simplify the crane design and as part of the cost minimization, instead the hoist rope  50  of the crane  10  is used. 
     The hoist rope  50  extends from the roller head  12  to the hook-type block  23  in order to be guided back to the boom system  11  after a load-dependent reeving at the hook-type block  23 . In detail, the rope course of the hoist rope  50  running back from the hook-type block  23  is determined by the pulley block  13  arranged at the roller head  12  and by the pulley block  14  mounted on the boom system  11  at the height of the rotor hub. At the end side, the hoist rope is attached to the lower abutment point, not shown, which is located at the pivotal connection piece, at the lung ram or at the revolving deck of the crane in dependence on the set hoisting conditions or on the crane design. In the drawing shown, the partial region  50   a  of the hoist rope  50 , which runs from the pulley block  14  to the lower pivotal connection point parallel to the boom axis, is used as a guide rope region  50   a.    
     An enlarged illustration of the roller head  12  can be seen from  FIG. 2 . This again provides an exact overview of the specific rope extent of the hoist rope  50  at the roller head  12 . 
     If the yoke  30  together with the rotor blade  101  is suspended at the hook-type block  23 , a sufficient tension of the hoist rope  50  then results in the guide rope region  50   a . The installation of the rotor blade  101  at the wind turbine  100  already results in a substantial reduction of the hoisting load. This immediately has effects on the pulling force in the hoist rope  50  and consequently on the tension in the guide rope region  50   a . At the same time, however, a large part of the wind attack surface is omitted so that the hoist rope tension is sufficient to avoid a dangerous rotating with the load-relieved yoke  30 . 
     The number of reevings of the hoist rope  50  at the hook-type block  23  is selected in dependence on the yoke  30  used. There is the possibility of using yokes with different physical dimensions which are especially configured for different rotor blades having different geometrical dimensions and weights. The total weight of the yoke  30 , the hook-type block  23  and the taken-up rotor blade  101  must be considered for the reeving. The number of reevings reduces the pulling force at the hoist rope. This is necessary in order to not allow the pulling force in the rope to become higher than permitted. This effect is actually unwanted in the region  50   a , even though it is unalterable. 
     The pulley block  14  is attached just below the target height (hub height) at the boom system  11  to be reached by the upper yoke edge. Even before the yoke  30  reaches the target height, the control ropes  40  running along on the guide rope region  50   a  of the hoist rope  50  by means of connection link  60  abut the pulley block  14  especially configured therefor. The direct abutment of the connection link  60  at the pulley block  14  is assisted by a moving of the connection link  60  into a corresponding apparatus  200  at the pulley block  14 ; and 
     The reasons for this abutment is that, at the ultimately reached hoisting height (height for the installation of the rotor blade  101  at the wind turbine  100 ), the connection link  50  is laterally fixed by the pulley block  14  or by the apparatus  200  so that the yoke  30  can be controlled and positioned very precisely via the control ropes  40  in this case. 
     Since the hub height of the wind turbine  100  and thus the moved out state of the boom system  11  is known, the pulley block  14  can be bolted to the boom system at the corresponding height on the basis of this knowledge to achieve a fixing of the connection link  60 . To be very free in the positioning of the pulley block  14 , the counter-connection elements at the boom are realized via clamping, bolt connections or other fixing mechanisms. 
     Since a certain horizontal pull a of the control ropes  40  can be tolerated (the yoke  30  has to be configured for this), a matching bolting point for the pulley block  14  will be found for each hub height of the wind turbine  100 . The pull α is desired since the connection link  60  can hereby be held in engagement better. 
     An embodiment of the pulley block  14  and of the connection link  60  can be seen from the schematic diagram of  FIG. 3  as well as from the corresponding sectional representation in  FIG. 4 . The pulley block  14  is stiffly positioned with its axis of rotation at the boom system  11 . The plate  200  is suspended at the pulley block  14  and is pivotally supported about the axis of the pulley block. The plate  200  furthermore carries a holding roller  201  which positions the plate  200  softly and damped by the hoist rope  50 . If, for example, the plate should be pivotally connected to the right, the coil angle of the hoist rope  50  about the pulley block  14  then increases in this respect. The pulling force acts as a restoring force in the hoist rope  50 . 
     The plate  200  has a metal abutment sheet  202  at its lower side, said metal abutment sheet not fully surrounding the hoist rope  50 . The center of the circular metal abutment plate  202  lies on the longitudinal axis of the hoist rope  50 . 
     The connection link  60  likewise has a plate, the metal abutment sheet  300 , whose shape corresponds to the metal abutment sheet  202  of the pulley block  14 . The interception and holding procedure is as described in the following. 
     The connection link  60  is taken along by the yoke  30  pulling upwardly via the control ropes  40 . When the two metal abutment sheets  202 ,  300  approach one another, they are aligned to one another via the slide block  301  of the connection link  60  until both metal abutment sheets  202 ,  300  lie on one another, as explicitly shown in  FIG. 4 . The system is now connected in shape-matched form via the slide block  301  so that forces from the control ropes  40  can be transmitted from the slide block  301  onto the metal abutment sheet  202  of the pulley block  14 . 
     The connection link  60  is furthermore still rotatable about the rope axis and can be aligned in accordance with the control rope forces. In this case, the slide block,  301  slides on the outer side of the metal abutment sheet  202  with the hoist rope  50  as the center. 
     The connection link  60  held at abutment can only move minimally perpendicular to the hoist rope  50  due to the large spacing “a” of the link rollers  302  and thus guarantees a fixed point at which the control ropes  40  of the yoke  30  can engage. A precise and fast installation of the rotor blade  101  is made possible. 
     The crane  10  in accordance with the invention also still has to be able to raise heavy loads without any larger reequipping. A particularly heavy load on the installation of wind turbines  100  is, for example, represented by the machine house. The reeving of the hoist rope  50  at the hook-type block  23  is selected accordingly; however, in this extreme load case, the introduction of the additional force in the guide rope region  50   a  of the hoist rope  50  into the boom system  11  should be avoided at all costs. The hoist rope  50  is fastened to the boom system  11  at the end side by rope clamping for this reason. Depending on the load type, the guide rope region  50   a  can be enlarged, reduced or omitted due to the fastening possibility variable at the end side. 
     For example, the machine house of the wind turbine  100  is first brought into the installation position. For this purpose, the end of the hoist rope  50  is held at the upper end of the boom system  11  via the rope clamp. A guide rope region  50   a  is not necessary due to the small wind attacking surface. 
     Subsequently to this, the yoke  30  is fastened to the hook-type block  23 . In this respect, the rope clamp, to whose end the installation rope of the reeving winch of the crane  10  is fastened, is pulled over the reeving winch to the boom section and is suspended.