Procedures for operating a crane and crane

Abstract

A method for operating a crane (50) with a movable undercarriage (10), a superstructure (12) rotatably mounted on it with a luffing boom system (54) and derrick boom (55) arranged thereon, wherein, in particular, for carrying out lifts with a luffed boom system (54), a constant ballast (200) is attached to the derrick boom (55), wherein the ballast is dimensioned such that the crane, when the boom system (54) is sufficiently luffed for the travel position, just barely does not tip backward. The method is characterized in that a special load table (BC) is integrated into the crane control system, which can be selected for the case of the attached constant ballast (200), and which ensures that the crane (50), when the boom system (54) is luffed, just barely does not tip backward.

Description

The invention relates to a method for operating a crane with a movable undercarriage, a rotatably mounted superstructure thereon with a luffing boom system arranged thereon and a derrick boom according to the preamble of claim 1. Large cranes, especially large crawler cranes, require a substantial counterweight to counteract the lifted payload and prevent the crane from tipping over. This counterweight can be provided by a central ballast, a superstructure ballast, and / or a ballast on the derrick boom. A ballast plate supported against the ground by appropriate means is commonly suggested as a derrick ballast. Alternatively, a completely suspended ballast or a derrick ballast carried by a ballast wagon are also possible. Against this background, special ballast wagons were developed that are designed as self-propelled vehicles and can therefore be moved together with the crane to ensure largely unrestricted crane operation. However, such solutions always require the complex in-house development of a suitable ballast wagon used exclusively for ballasting. Furthermore, such a ballast wagon must be transported separately to the construction site for crane operation, which negatively impacts the operating costs, as these generally depend on the required ballast mass. On the other hand, German patent DE 10 2011 105 960 A1 already discloses the use of an auxiliary crane with a telescopic boom as derrick ballast for the crane. This ballasting option can be used, for example, during regular crane operation or even during the crane setup process, specifically during the erection of the luffing jib system. A relatively small crane required for the setup of the large crawler crane could be used as the auxiliary vehicle. Furthermore, in the unpublished DE 10 2014 012 661 A1 it has already been proposed to use an auxiliary crane as a ballast wagon with an additional suspended ballast. However, it should be noted that a lattice crane with suspended ballast must comply with several failure criteria. It is obvious that the entire crane must be prevented from tipping backward over the tipping edge, i.e., over the end of its base on the ground. This can be achieved by monitoring the overall center of gravity. Another important feature is preventing the uncontrolled rearward swing of a boom section around its luffing axis. Boom sections can be the main boom, i.e., the boom system, or the derrick boom. While fall-back devices counteract this effect, their effectiveness is limited. The crane's structural integrity must also be considered in the event of "load breakage" as defined by EN 13000. In this case, the crane must not tip backward. To prevent a situation in which the crane tips backward or is pulled backward by the suspended ballast, EP 2 308 792 A1 already proposed that a triangular derrick significantly reduces the distance along the longitudinal axis of the superstructure between the superstructure axis and the suspended ballast. In this solution, a very large derrick ballast is applied in order to reduce the derrick ballast radius. A method for operating a crane of this type is already known from WO 2005 / 097 661A1. DE 200 14 268 U1 discloses a crane in which ballast weight is provided that can be positioned as close as possible to the luffing axis of the derrick jib. Reference should also be made to a crane according to WO 2003 / 040 016 A1. The object of the invention is to provide a method for operating a crane and a corresponding crane which, in particular, provides the necessary counterweight quickly and easily for the load conditions during the operation of the crane using the simplest possible means. According to the invention, this problem is initially solved by combining the features of claim 1. Accordingly, a crane with a movable undercarriage, a superstructure rotatably mounted thereon, a luffing boom system arranged thereon, and a derrick boom in which an auxiliary crane is used as derrick ballast, is further developed by attaching a constant ballast to the derrick boom, particularly for performing lifts with a luffed boom system. This constant ballast is dimensioned such that the crane, when the boom system is sufficiently luffed for the travel position, is just barely able to tip backward. According to the invention, a special load table (BC) is integrated into the crane control system, which can be selected for the case of the attached constant ballast. This table ensures that the crane, when the boom system is luffed, is just barely able to tip backward. Further advantageous embodiments of the invention are set out in the dependent claims following the main claim. Advantageously, a crossbeam attached to the derrick boom can support counterweight plates suspended via appropriate connecting devices. A further advantage can be that counterweight plates can be attached directly to the guy rods hanging from the derrick boom via appropriate connecting devices. An advantage of a further development of the invention may be that, in particular for erecting the boom system to increase the moment, counterweight plates are taken from the upper carriage ballast and picked up via the connecting means. The method according to the invention makes it possible, for example, after uncoupling a ballast attached to the derrick boom, which consists at least of the ballast base plate with a ballast located thereon, to attach counter-stack plates to the crossbeam still attached to the derrick boom or directly via appropriate connecting means, in order to form a constant ballast attached to the derrick boom. Such a constant ballast is sufficient, for example, to achieve the necessary load-bearing capacity for the assembly of components of systems, such as wind turbines, when the maximum ballasting of the main crane with central ballast and superstructure ballast is insufficient. This constant ballast can advantageously be directly transferred from the decoupled ballast base plate via the connecting elements of the counterweight plates, if required. In this alternative design, the attached crossbeam of the previously described variant is therefore no longer necessary. Advantageously, special load tables are integrated into the crane control system, which can be selected in the case of the attached constant ballast, ensuring that the crane, with the boom system advantageously tilted, does not tip backwards. The method is particularly advantageous for erecting the boom system because, to increase the moment, counterweight plates are taken directly from the superstructure ballast and stacked on the ballast base plate. This means the counterweight plates no longer act as superstructure ballast but as derrick ballast, increasing the moment without the need to transport additional counterweight plates to or from the derrick. A crane according to the invention for carrying out the aforementioned method is defined in claim 6 and the dependent claims that follow it. Such a crane comprises a movable undercarriage, a superstructure rotatably mounted thereon with a luffing boom system and derrick boom arranged thereon, and a crane control system.It is characterized by the fact that, as a derrick ballast, it has a ballast device which consists at least of rods articulated to the derrick boom with receiving means arranged on these for receiving counterweight plates, and that a load table (BC) is integrated into the control of the crane in such a way that it can be selected when operating the crane with the ballast device and enables operation with a constant ballast (BC) which, when taking on the derrick ballast sufficient for the corresponding lifting task, ensures during operation of the crane that it just barely does not tip backwards safely. The crane according to the invention is advantageously further developed in that a crossbeam is attached to the poles, to which either the lifting means or a ballast base plate can be attached. Advantageously, longitudinally variable elements in the form of hydraulic cylinder arrangements can be provided between the derrick boom and the crossbeam. At least one additional counterweight stack consisting of counterweight plates can be stacked on the ballast base plate. According to the invention, connecting means for the direct attachment of counterweight plates to form a counterweight assembly suspended from the derrick boom can be additionally fastened to the crossbeam. These connecting means can be mandrels, such as those known from DE 20 2004 009 497 U1. Advantageously, just enough counterweight plates are installed in the counterweight assembly so that the crane, when the boom system is raised sufficiently for the travel position, is just barely stable and does not tip backward. According to another advantageous aspect of the invention, support feet are arranged on the traverse, onto which the traverse can be placed, particularly during transport. Further features, details and advantages of the invention are explained in more detail with reference to exemplary embodiments shown in the figure. Figure 1 shows a side view of the crane according to the invention in a representation with the boom system largely erected; Figures 2 and 3 show side views of the crane according to the invention, only partially shown, with an attached auxiliary crane in different embodiments, the boom system to be erected not being shown; Figure 4 shows a perspective view of an embodiment of the derrick ballast; Figure 5 shows another perspective view of the derrick ballast according to Figure 4; Figure 6 shows a side view of the derrick ballast according to Figures 4 and 5; Figures 7, 8 to 9 show details of the derrick ballast; and Figures 10 and 11 show different configurations of the derrick ballast according to alternative embodiments of the invention. The crane 50 according to the invention is constructed as shown in Fig. 1. The crane 50 has a chassis 10 with a running gear, which in the drawn embodiment is designed as a crawler chassis and comprises two crawler tracks arranged on the right and left. A superstructure 12, rotatably mounted about an upright pivot axis, is arranged on the chassis 10. The superstructure 12 carries a main boom 54, which, within the scope of the invention, is referred to as the boom system and can thus include all conventional boom configurations. This boom 54 is articulated to the superstructure 12 about a horizontal luffing axis and has a hoist cable (not shown) in the usual manner. On the rear side of the superstructure 12 opposite the pivot point of the boom 54, it carries an operating ballast 58, which counteracts the tipping moment induced by the boom 54 or a load suspended from it. Behind the boom system 54, the rearward-oriented derrick boom 55 is mounted, wherein the boom system 54 or the main boom head is braced in a manner known per se via the adjustable bracing 14 on the derrick boom 55. When lifting very heavy loads, it is necessary to brace the derrick boom 55 using an additional derrick ballast. Typically, a derrick ballast suspended above the ground, shown here as constant ballast 200, is used for this purpose. In contrast to the prior art, the crane 50 according to the invention provides a novel approach to ballasting the derrick boom 55, particularly during the assembly of the boom system 54, where especially high counter-moments must be generated. This novel approach to ballasting, particularly during the erection of the boom system 54, is shown in particular in Figs. 2 and 3. For reasons of space, the boom system 54, which is still lying on the ground and has yet to be erected, is not shown in these two illustrations. Figures 2 and 3 each show a ballast device 100 with a heavy counterweight serving as derrick ballast. The design of the ballast device 100 is shown in particular in Figures 4, 5 to 6, and additionally in the detailed illustrations 7 to 9. A key element of this ballast device 100 is the auxiliary crane 1, whose entire weight forms part of the derrick ballast. An auxiliary crane 1, such as the one used in the present invention, has a mass of approximately 180 t. Thus, the use of the auxiliary crane eliminates the need to transport 180 t of counterweight to the construction site. To ensure rapid deployment, the auxiliary crane 1 can advantageously drive onto the ballast base plate 3 via a ramp 2 (see Figure 6). Unlike prior art solutions, no further connection between the auxiliary crane 1 itself and the crane 15 is provided here. In addition to the auxiliary crane 1, further space can be provided on the ballast base plate to stack additional ballast, in particular further counterweight plates 4. The counterweight plates 4 can be divided into four counterweight stacks 5, 5', 5'', 5''', as shown in Fig. 4. A sensor device 6 can be provided on the ballast base plate 3 to detect when the ballast base plate has completely lifted off the ground and to transmit this information to the control system of the crane 50, which is not shown in detail here. The ballast device 100 is connected to the derrick boom 55 via parallel guy wires 51, 51'. The spacing of the guy wires is predetermined within certain limits by the width of the derrick boom 55. This spacing is significantly smaller than the width of the auxiliary crane 1. A crossbeam 52 is provided to ensure a secure connection. This crossbeam connects the guy wires 51, 51' and corresponding connecting brackets 53, which connect the crossbeam 52 to the ballast base plate 3. As shown in Fig. 4, the connecting brackets 53 and the crossbeam 52 form a gate into which the auxiliary crane 1 can move. As shown in Fig. 2, variable-length cylinder assemblies 61 are attached to the guy rods 51, 51', which transmit the force to the derrick boom 55. If these cylinders 61 do not move in sync, the crossbeam 52 will be jammed, as shown, for example, in Fig. 9. If the difference in movement is greater than, for example, 1000 mm, which is detected by an inclination sensor (not shown in detail here), the crane control system can compensate for this difference by adjusting the cylinders 61 accordingly. Bolted connections 56 are provided between the crossbeam 52 and the connecting brackets 53 that support the ballast base plate 3. This allows for some pivoting capability. However, the ballast base plate 3 is generally aligned parallel to the crossbeam 52. To increase the mass of auxiliary crane 1, it can be equipped with a central ballast. An additional ballast is also possible. Furthermore, an additional load can be attached to the hook of auxiliary crane 1, as not shown here, to increase the counter-moment. Even without additional ballast or an additional load on the hook, the total mass of, for example, 480 t can be achieved. This can therefore be increased even further by adding more ballast and a hook load. With the sufficiently large mass of the ballast device 100, the crane 50 can erect its long boom system 54. The erection process is monitored by the crane control system and a suitable erection load table. Once the boom is erected, the crane can operate with a significantly smaller counterweight arrangement 200 and, for example, perform the lifts necessary for erecting a wind turbine. Several wind turbines often need to be erected on a construction site. The crane could also travel from one assembly site to another with the boom system 54 erected. In the case of the crane 50 presented here, the moment of the erected boom system 54 is insufficient to lift the large mass of the ballast device 100 from the ground. To nevertheless enable the main crane 50 to be moved or rotated, detachable connections, in particular bolted connections 56, are provided between the crossbeams 52 and the connecting supports 53. After the boom system 54 has been erected, the bolted connections 56 can be released. Thus, the main crane 50 is free and can be moved or rotated. To achieve the necessary lifting capacity, for example for the assembly of the components of a wind turbine, even maximum ballasting of the main crane 50 with central ballast 57 and superstructure ballast 58 is insufficient. Therefore, additional derrick ballast is required. This derrick ballast can be provided by a counterweight arrangement 200, as shown in Fig. 1 or in Figs. 10 and 11. A first embodiment of this counterweight arrangement 200, also referred to as constant ballast, is shown in Fig. 10. Here, a known mandrel 60 is inserted directly onto the crossbeam 52, from which the ballast device 100 has been detached, via appropriate connecting means 59. This mandrel is known from German Utility Model 20 2004 009 497 U of the same applicant and has been used for many years to hold counterweight plates. Each mandrel 60 can support one or more counterweight plates 4. Advantageously, precisely the number of counterweight plates 4 are installed in the counterweight plate arrangement 200 such that the crane, with the boom system 54 raised sufficiently for the travel position, is just barely not tipping backward. For this purpose, a special load table BC can be selected in the crane control system to ensure a safe condition at all times.The system increases the load-bearing capacity without rebalancing the suspended ballast pallet. For example, after the mandrels 50 are attached, the main crane 50 could move them via the ballast device 100, and each mandrel could automatically pick up the required two counterweight plates 4, as shown in Fig. 10. According to the invention, no time-consuming restacking of the ballast device 100 would be necessary. According to an alternative embodiment, as shown in Fig. 11 and also as can be seen in Fig. 1, the crossbeam 52 with the ballast device 100 can be removed. The pins 60 are then attached directly to the guy rods 51, 51' with the corresponding connecting means 59. It is advantageous that monitoring of the counterweight assembly 200 when it is "lifted off the ground" is unnecessary. Its relatively low weight prevents damage to the crane during travel or rotation, even when placed on the ground. Furthermore, in the USA, for example, ballast that is not placed on the ground is not considered suspended ballast and therefore does not fall under the relevant regulations. According to load capacity table BC, only those luffing positions of the boom system 54 are permissible that ensure the counterweight assembly remains constantly lifted off the ground. Another key aspect of the invention is that the variable effective radius of the counterweight plates 4 is modified as follows. This allows the upper carriage ballast 58, necessary for the operation of the crane 50, to be removed during erection and used in the ballast device 100. This significantly increases the counter-moment, and fewer counterweight plates 4 are required. Consequently, the transport costs for delivering the counterweight plates to and from the construction site can be reduced. As shown in Fig. 8, support feet 63 are provided on the crossbeam 52. The crossbeam 52 can be placed on these feet. In the embodiment shown in Fig. 3, a spacer device in the form of a guide frame 62 is additionally used to enable a larger ballast moment. This is arranged between the ballast base plate 3 and the superstructure 12 of the crane 50.

Claims

Method for operating a crane (50) with a movable undercarriage (10), a superstructure (12) rotatably mounted on it with a luffing boom system (54) and derrick boom (55) arranged thereon, wherein, in particular for carrying out lifts with a luffed boom system (54), a constant ballast (200) is attached to the derrick boom (55), wherein the ballast is dimensioned such that the crane, when the boom system (54) is sufficiently luffed for the travel position, just barely does not tip backwards. The method is characterized in that a special load table (BC) is integrated into the crane control system, which can be selected for the case of the attached constant ballast (200), and which ensures that the crane (50), when the boom system (54) is luffed, just barely does not tip backwards. Method according to claim 1, characterized in that counterweight plates are suspended from a traverse (52) attached to the derrick boom (55) via appropriate connecting means (60). Method according to claim 1, characterized in that counterweight plates are suspended directly from guy rods (51) hanging down from the derrick boom (55) via corresponding connecting means (60). Method according to one of the preceding claims, characterized in that, in particular for erecting the boom system (54) to increase the moment, counterweight plates (4) are taken from the superstructure ballast (58) and picked up via the connecting means. A crane for carrying out the method according to one of claims 1 to 4, comprising a movable undercarriage (10), a superstructure (12) rotatably mounted on it with a luffing boom system (54) and derrick boom (55) arranged thereon, and a crane control system, characterized in that it has a ballast device (200) as derrick ballast, which consists at least of rods (51) articulated to the derrick boom (55) with receiving means (60) arranged on these for receiving counterweight plates (4), and in that a load table (BC) is integrated into the crane control system in such a way that it can be selected when operating the crane (50) with the ballast device (200) and enables operation with a constant ballast (BC) which, when taking on the derrick ballast sufficient for the corresponding lifting task, ensures during operation of the crane (50) that it just barely does not tip backwards safely. Crane according to claim 5, characterized in that a crossbeam (52) is attached to the poles (51), to which either the receiving means (60) or a ballast base plate (3) can be attached. Crane according to one of claims 5 or 6, characterized in that length-variable elements in the form of hydraulic cylinder arrangements are provided between derrick boom (55) and traverse (52). Crane according to one of the preceding claims, characterized in that support feet (63) are arranged on the crossbeam (52).

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