Telescopic boom of a crane and methods for its bracing, as well as for erecting telescopic extensions

Abstract

Telescopic boom (16) of a crane (10) with a pivot section (18), telescopic sections (20) extendable from the pivot section (18) and a guying system (24) for the telescopic boom (16), which has two guying supports (26) mounted on one of the sections (20), a guying cable (28) supported by each guying support (26) and at least one adjusting device for pivoting the guying supports (26), and wherein winches (30) for defined guying of the guying cables (28) are arranged on the guying supports, characterized in that a telescopic extension (22) can be bolted to lower bolting points (42) on the boom head (44) of the telescopic boom (16), wherein the lower bolting points (42) form an axis of rotation about which the telescopic extension (22) bends when erected, wherein the winches (30) of the The guy wires (26) are designed to exert the forces required to erect the telescopic extension (22).

Description

The invention relates to a telescopic boom of a crane according to the preamble of claim 1, a method for bracing it, and a method for erecting telescopic extensions. To increase the lifting capacity of a crane, it is already known to attach guy wires to or behind the boom. Spatial guy wires are used to further increase lifting capacity. An advantage of such spatial guy wires is that the crane boom exhibits no or very minimal deviations from the luffing plane. These deviations can be caused, for example, by wind loads or uneven sunlight. Such a crane is known, for example, from DE 202 08 740 U1. Here, a telescopic boom supports two guyed supports that are spread out in a V-shape in the operating state. These supports are connected at their free, cantilevered ends by guy wires that run from the guyed supports. When the telescopic boom is extended and the guyed supports are raised accordingly, the guy wires are pulled out from their ends. Once the telescopic boom reaches a pre-selected extended length, the guy wires must be fixed to the guyed supports at the corresponding length. It is essential that the two guy wires of the spatial bracing are of the same length. The forces absorbed by the guy wires are of secondary importance. When the guy wires of equal length are tensioned, the telescopic boom is positioned in a statically optimal central position relative to the luffing plane. For bracing large telescopic booms, a telescopic boom for a crane with a pivoting section and telescopic sections extendable from the pivoting section was already described in DE 10 2008 035 583 A1. This method includes a bracing system for the telescopic boom with two bracing supports mounted on one of the sections, each supporting a bracing cable, and at least one adjustment device for pivoting the bracing supports. Winches for receiving the bracing cables are arranged at the free ends of the bracing supports, and bracing cylinders for defined bracing of the bracing cables are arranged in the bracing supports, with the free ends of the bracing cables attached to these cylinders. In this previously known bracing method, separate bracing cylinders are provided at each bracing support, through which the bracing is achieved.The winches present in this previously known solution served only to wind up or unwind the respective guy rope. From DE 20 2004 008 083 U1 a telescopic boom with a guying system is also known, in which winches are arranged on the guying supports for the defined guying of the guy ropes. German patent DE 20 2008 003 734 U1 discloses an auxiliary device for setting up an auxiliary boom on the main boom of a mobile crane. The auxiliary boom is first connected to the lower connection points on the main boom head. The auxiliary boom is then raised to allow the upper connection to be made. DE 20 2008 003 734 U1 proposes using the crane's hoist rope for this purpose, but also mentions in general terms that, alternatively, a main boom guying device (e.g., a "Superlift") could perform this function. The object of the present invention is to further develop a generic telescopic boom with a bracing system and a boltable telescopic extension in such a way that the erection of the telescopic extension is made possible by structurally simple means and without the need for a separate auxiliary crane or the use of the main hoisting rope. This problem is solved by a telescopic boom with the features of claim 1. According to the invention, a telescopic extension can be bolted to the boom head of the telescopic boom at lower bolting points, the lower bolting points forming an axis of rotation about which the telescopic extension folds when erected. The core of the invention is that the winches of the guying supports fulfill a dual function: They not only serve to tension the guy ropes in a defined manner during crane operation, but are also designed to exert the necessary high forces for erecting the telescopic extension. In contrast to the prior art, where the winches of a guying system (if present) merely serve to wind and unwind the ropes, while the actual tensioning forces are applied by separate cylinders (see DE 10 2008 035 583 A1), or where the erection of an extension is carried out by means of the main hoisting rope (see DE 10 2008 035 583 A1), the invention provides a dual function.DE 20 2008 003 734 U1 ), the invention utilizes the winches of the guying system itself for the heavy lifting operation of erection. This enables a significant simplification of the design and an efficient setup process, as no additional lifting devices such as guying cylinders or the main lifting cable are required for this purpose. Preferred embodiments of the invention are set forth in the dependent claims. Accordingly, the two guy wire supports can be pivoted from a substantially parallel transport position, folded against one of the shots, into an upright operating position. Advantageously, the winches have external gear teeth, each of which can be locked via a pawl. Winch encoders can advantageously be arranged on the winches, while transponders can be attached to the gear teeth on the outer diameter of the winches. The monitoring signals received by these encoders or transponders can advantageously be fed to a control system. The invention also relates to a crane, preferably a mobile crane, with a telescopic boom and an optional telescopic extension that can be connected to it. The telescopic extension is a lattice boom that can be bolted to the head of the telescopic boom. The invention also relates to a method for guying a telescopic boom with the aforementioned features. According to the invention, with the telescopic sections and guying supports preferably extended, the respective winch on each guying block is moved to a winch position corresponding to the boom length in order to tension the respective guying cable to a defined length. Crucially, this method starts with a defined length of guying cable. This ensures that the boom can be pulled straight, as guying is applied from both sides with a precisely defined length. To determine the length of the guy wire, the current position of the winch can advantageously be displayed via a winch rotary encoder and / or additionally via several transponders attached to a toothed section on the outer diameter of the winch, with these values ​​being forwarded to the crane control system. The invention further relates to a method for erecting a telescopic extension, wherein the erection process can be accomplished by means of the guy wires and the winches arranged on them. For this purpose, with the telescopic sections extended or retracted and the guy wires extended, a telescopic extension is bolted to the essentially horizontally oriented telescopic boom in such a way that the telescopic extension bends relative to the telescopic boom when it is rocked upwards, while the tip of the telescopic extension rolls to the ground via a trolley attached to it, before the telescopic extension is pivoted upwards around the bolt points by means of the winches arranged at the guy wires and, after reaching the final position, is completely bolted to the telescopic boom. The telescopic sections of the telescopic boom can only be extended to the desired length to a particularly advantageous extent once the telescopic extension is completely bolted to the telescopic boom. Further features, details and advantages of the invention are explained in more detail with reference to an exemplary embodiment shown in the drawing. Figure 1 shows a schematic representation of a mobile crane with a telescopic boom according to the invention, Figure 2 shows a part of Figure 1 in a side view to illustrate the erection of a telescopic extension, and Figures 3, 4, 5, 6 to 7 show the different stages of the process of erecting a telescopic extension. Fig. 1 shows a mobile crane 10 with an undercarriage 12 and a superstructure 14. A telescopic boom 16, consisting of a pivot section 18, a series of telescopic sections 20, and a telescopic extension 22, is arranged on the superstructure 14. The attached telescopic extension consists of a lattice boom section, as shown in Fig. 1. The telescopic boom 16 has a guying system 24, which essentially consists of two guying supports 26, in this case articulated in a V-shape to the pivot point 18, with each guying support 26 having a guying cable 28 supported by the guying supports 26. This cable can be wound up, unwound, and tensioned via winches 30 arranged on the guying supports 26, with the guying cables 28 running over pulleys 32 arranged on the guying supports 26. In the area of ​​the winches 30, which have teeth 34 on their outer circumference (see Fig. 2), locking pawls 36 are arranged, which, after engaging between the teeth 34, result in a positive locking of the winches 30. The number 40 shows the guy rods of the V-shaped, expandable guy supports 26. Similar to what was already shown in DE 10 2008 035 583 A1, the bracing system 24 presented here can be used to ensure that the guy wires of the bracing system for very large telescopic booms are of the same length, so that the resulting large forces can be absorbed evenly. For this purpose, the V-shaped, expandable guy wire supports 26 are provided on the pivot section 18. These supports, via their winches 30, are able to tension the guy wires 28, which are attached to the free end of the telescopic boom, to a defined length. This ensures that the guy wires on both sides have defined lengths, which then ensures that the telescopic boom runs at least approximately in a straight line. The maximum operating force that can be applied via the winches should be dimensioned so that they can fully utilize the forces that can be transmitted by the cable.This makes it possible to straighten the boom 16 in almost any situation. In this respect, the bracing 24 largely corresponds to the bracing according to DE 10 2008 035 583 A1. The guying system 24 presented here according to the invention is, however, significantly simplified by the fact that the provision of corresponding guying cylinders, as was required in the prior art, is dispensed with. In the solution described here, the corresponding tension forces for the guy cables 28 are applied solely by the winches 30. Due to its design, the guy wire 24 presented here not only allows the telescopic boom to be pulled straight and stably braced in a straight position. Because of its design, the guy wire 24 can also be used to erect a telescopic extension for the mobile crane, which, for example, could consist of a long lattice boom section 22. This is made possible because the winches 30 can now also take over the task of tensioning the cables and therefore exert correspondingly high forces on the guy wires 28. With the solution according to the invention, comparatively longer booms, consisting of a telescopic main boom and a jib (Fig. 2), can be erected. If the main boom is fully retracted (Fig. 1, pivot section 18 and telescopic sections 20) and the lattice boom section 22, serving as a telescopic extension, is fully connected to the telescopic boom, as is typical in the prior art, then the luffing cylinder 52 is only able to luff a certain length of the entire boom system. Key criteria here are: - the moment caused by the weight of the boom system around the luffing axis of the boom, - the maximum force to be applied by the luffing cylinder 52, and - the unfavorable geometric conditions when the pivot section is oriented completely or substantially horizontally. Figures 2, 3, 4, 5, 6 to 7 show in detail, according to the present invention, how a correspondingly longer telescopic extension in the form of a lattice mast section 22 can be erected by means of the guying 24. The erection sequence can be explained with reference to Figures 3, 4, 5, 6 to 7. Fig. 3 shows the mobile crane 10 in its starting position, in which the telescopic boom 16 is essentially horizontal, with the individual telescopic sections 20 retracted into the pivot section 18. The outriggers 26 are still shown in a folded position. In Fig. 4, the guying supports 26 are spread out in a V-shape. The respective free ends of the guying supports 26 are braced against the superstructure 14 via guy rods 40. In Fig. 5, a telescopic extension 22, consisting of a corresponding long lattice mast section, is bolted to the lower bolting points 42 on the boom head 44 of the telescopic boom 16 in the horizontal position (see Fig. 2). The tip of the telescopic extension 22 rests on a movable carriage 46. As also shown in Fig. 2, the upper bolting points 48 are not yet bolted together in the configuration shown in Fig. 5. The guy wires 28 are attached to corresponding anchor points 50 (see Fig. 2) at the front of the telescopic extension 22. As shown in Fig. 6, in the next step the still retracted telescopic boom 16 is pivoted upwards from the horizontal position to an inclined position via its corresponding rocker cylinder 52. At the same time, the telescopic extension 22 bends about the lower bolt points 42 and moves along the ground on the carriage 46 with its tip mounted on it. Finally, in the last step according to Fig. 7, the telescopic extension 22 is raised via the bracing 24, i.e. by appropriately actuating the winches 30, and aligned towards the telescopic boom 16 in such a way that the upper bolting points 48 can be connected to each other, so that the telescopic boom is securely connected to the telescopic extension at all bolting points 42 and 48. Subsequently, the telescopic boom can be extended as required, with the winches 30 adjusting the guying after reaching the end position by setting the appropriate length of the guy cables 28. After the guy cables 28 have been tightened accordingly, the respective winch 30 is locked in the right-hand guying position via the pawl 36 and the toothed section 34. The telescopic extension 22 is removed in reverse order. According to the invention, the lattice mast section 22, which serves as a telescopic extension, is now supported at its free end on the ground when the rocker cylinder 52 rocks the pivot section. Since the connection (i.e., the bolt points 48) is open, only the base weight of the lattice mast section rests on the roller head of the smallest telescopic section. Thus, not only is the weight that the rocker cylinder 52 has to move reduced, but also the effective distance of the center of gravity to the rocker axis. The latter further reduces the moment about the rocker axis. Once a rocking angle is reached at which the rocker cylinder 52 can continue to rock the entire boom system in the connected state, the winches 30 pull up the lattice mast section and spatially brace the boom. Instead of the connection point formed by the bolt points 48, a modified embodiment could also use an anchor point, since this point is only subjected to compressive stress anyway. In this case, a rocker operation with the lattice mast section 22 could also be possible via the spatial bracing. However, the load moment limitation would have to be adjusted in this special case. The advantage based on the equal length of the guy wires 28 would be lost.

Claims

Telescopic boom (16) of a crane (10) with a pivot section (18), telescopic sections (20) extendable from the pivot section (18) and a guying system (24) for the telescopic boom (16), which has two guying supports (26) mounted on one of the sections (20), a guying cable (28) supported by each of the guying supports (26) and at least one adjusting device for pivoting the guying supports (26), and wherein winches (30) for defined guying of the guying cables (28) are arranged on the guying supports, characterized in that a telescopic extension (22) can be bolted to lower bolting points (42) on the boom head (44) of the telescopic boom (16), wherein the lower bolting points (42) form an axis of rotation about which the telescopic extension (22) bends when erected, wherein the winches (30) of the The guy wires (26) are designed to exert the forces required to erect the telescopic extension (22). Telescopic boom (16) according to claim 1, characterized in that the two guying supports (26) can be pivoted from a substantially parallel transport position folded against one of the sections (20) into an erect operating position. Telescopic boom (16) according to claim 1 or 2, characterized in that the winches (30) have toothing (34), in particular external toothing, each of which can be locked via a pawl (36). Telescopic boom (16) according to claim 3, characterized in that the winches (30) have winch rotary encoders and / or several transponders attached to the toothing on the outer diameter of the winches (30). Telescopic boom (16) according to one of claims 1 to 4, characterized in that all monitoring signals can be supplied to a control system. Crane (10), preferably a vehicle crane, with a telescopic boom (16) according to one of claims 1 to 5 and a telescopic extension (22) that can optionally be connected to it. Method for bracing a telescopic boom (16) according to one of claims 1 to 5, characterized in that, with telescopic sections (20) and bracing supports (26) extended, the respective winch (30) on each bracing block (26) is moved to a target position suitable for the boom length, so that the respective bracing cable (28) is tensioned in a defined manner. Method according to claim 7, characterized in that the respective actual position of the winches (30) is displayed via a winch rotary encoder and / or additionally via several transponders attached to a toothing (34) on the outer diameter of the winch (30), wherein these values ​​are forwarded to the crane control. Method for erecting a telescopic extension (22) by means of the bracing of a telescopic boom (16) according to one of claims 1 to 5, characterized in that, with the telescopic sections (20) retracted and the bracing supports (26) extended, a telescopic extension (22) is bolted to the horizontally aligned telescopic boom (16) in such a way that the telescopic extension (22) bends relative to the telescopic boom (16) when it is tilted, while the tip of the telescopic extension (22) rolls on the ground via a trolley (46) attached to it, before the telescopic extension is pivoted upwards around the bolt points (42) by means of the winches (30) arranged on the two bracing supports (26) and, after reaching the end position, is completely bolted to the telescopic boom (16). Method according to claim 9, characterized in that the telescopic sections (20) of the telescopic boom (16) are only extended to the desired length when the telescopic extension (22) is completely bolted to the telescopic boom (16).

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