Mobile crane with a detachable A-frame

Description

[0001] The present invention relates to a mobile crane, in particular a crawler crane, according to the preamble of claim 1, and to a divisible A-frame for such a crane.

[0002] In many mobile cranes, especially crawler cranes, it is known to brace the main boom via a pivoting support bracket or A-frame attached to the superstructure and to pivot the boom and A-frame unit by means of a retraction mechanism.

[0003] For example, EP 2 275 378 A1 discloses an A-frame designed for construction machinery such as a crawler crane. This A-frame has two-part folding rear and front beams. In its resting or folded state, the front beams are folded onto the rear beams and pivoted backwards. To prevent damage to the rear beams, the A-frame is equipped with a locking mechanism that prevents damage to a locking element caused by the unintentional release of a locking mechanism.

[0004] The Figure 1Figure 1 shows a side view of a crawler crane 1, also known from the prior art, comprising a chassis 2 with crawler tracks, a superstructure 3 rotatably mounted on the chassis about a vertical axis, with a driver's cab 4 located at the front, a superstructure ballast 5 located at the rear, and a main boom 6 pivotable about a horizontal axis. A load-handling device or load hook 7 is connected via a hoist cable 8 to a hoist winch 9 mounted on the superstructure 3. An A-frame 10, connected to the main boom 6 via retaining rods 12, is pivotally connected to the superstructure 3 about a horizontal axis.

[0005] Typically, the retraction mechanism comprises a retraction winch 20 arranged on the superstructure 3 with a retraction cable 21, which is guided over a pulley or pulley assembly 24 arranged at the end of the A-frame 10 and a pulley or pulley assembly 22 arranged on the superstructure 3. By retracting / paying out the retraction cable 21 using the retraction winch 20, the distance between the pulleys or pulley assemblies 22 and 24 can be decreased / increased, thereby pivoting the A-frame 10 and the boom 6.

[0006] The main boom 6, together with the A-frame 10 and the retaining bars 12, forms an adjustment unit which is operated by the winch cable drive. By operating the hoist winch 9, the free length of the hoist cable 8 can be changed, thereby raising or lowering loads attached to the load hook 7. Some cranes are equipped with a derrick boom pivotally connected to the superstructure 3 in addition to the main boom 6. In this case, the A-frame 10 is connected to the derrick boom via the retaining bars 12, not to the main boom 6.

[0007] Typically, the basic unit, consisting of the undercarriage and superstructure without the crawler tracks and superstructure ballast, is transported to the deployment site along with the A-frame and assembled there. The A-frame's own weight contributes significantly to the overall weight of the transported unit, which can be problematic with regard to regulations concerning the maximum permissible transport weight for (road) transport – especially in countries with strict regulations in this regard. Disassembling the entire unit, including the A-frame and retraction mechanism, is also disadvantageous, as assembly and disassembly are comparatively complicated and time-consuming, and there is a risk of damaging sensitive components of the retraction mechanism during assembly, disassembly, or transport.

[0008] Against this background, the present invention aims to provide a mobile crane with an A-frame, which has a transportable basic unit with reduced weight and low assembly effort. According to the invention, this objective is achieved by a crane with the features of claim 1. Accordingly, a mobile crane, in particular a crawler crane, is proposed, comprising an undercarriage with a chassis, a superstructure rotatably mounted on the undercarriage about a vertical axis, a boom pivotally connected to the superstructure about a horizontal axis, an A-frame pivotally connected to the superstructure about a horizontal axis and connected to the boom via a bracing device, and a hoisting mechanism, wherein the A-frame is pivotable by means of the hoisting mechanism, and wherein the A-frame is divisible, i.e.,The invention is designed to be disassembled for transport and comprises a beam pivotally mounted to the superstructure and a folding beam detachably connected to the beam. The folding beam and the superstructure each have fastening means by which the folding beam can be detachably mounted to the superstructure, wherein the folding beam is pivotably connected to the beam about a, in particular, horizontal axis (pivot axis) and can be locked to it, and wherein the fastening means of the folding beam and the superstructure can be brought together by pivoting the folding beam about the axis (pivot axis). According to the invention, the folding beam can be removed from the beam and detachably mounted to the superstructure.

[0009] Because the A-frame can be disassembled into a beam and a folding beam, it is possible to remove only part of the A-frame, specifically the beam, for transport, while leaving the other part, particularly the folding beam, attached to the superstructure along with the retraction mechanism. This allows the base unit, which is typically disassembled for transport, to be reduced to an even smaller and lighter transport unit without having to remove the retraction mechanism as well, thus simplifying and speeding up the assembly process. Furthermore, the sensitive and expensive components of the retraction mechanism are protected against damage during handling and transport.

[0010] The removable part of the A-frame for transport is particularly quick and easy to dismantle, compact, and therefore requires minimal transport volume. The reduced transport weight of the disassembled base unit offers significant transport advantages in terms of costs and regulatory approvals, especially in countries with strict regulations regarding maximum transport weight.

[0011] The term "folding boom" is to be interpreted broadly and does not necessarily require that this part be foldable. It can refer to any part of the A-frame, which, in particular, can remain on the superstructure after the boom has been removed. The boom and A-frame can pivot about the same or different axes. The boom can be the main boom or a derrick boom.

[0012] Advantageous embodiments of the invention will become apparent from the dependent claims and the following description.

[0013] According to the invention, the folding beam is designed to be detachable from the main beam and reattached to the superstructure. For transport, the main beam is therefore detached and transported separately, while the folding beam is reversibly attached to the superstructure and transported together with it.

[0014] In one embodiment, the components of the hoisting mechanism attached to the A-frame are arranged on the folding beam. This makes it possible to leave the part of the A-frame connected to the hoisting mechanism attached to the superstructure for transport, while the rest of the A-frame, namely the beam, can be removed and transported separately. This results in quick and easy disassembly and assembly of the A-frame. The components of the hoisting mechanism do not need to be removed from the supporting structures.

[0015] In a further embodiment, the retraction mechanism comprises a retraction winch arranged on the superstructure, a first roller assembly also arranged on the superstructure, and a second roller assembly arranged on the folding beam. The retraction cable can be wound multiple times around the roller assemblies. In particular, the second roller assembly is arranged at the outer end of the A-frame. This allows the folding beam to be small and to comprise only the frame of the A-frame surrounding and supporting the second roller assembly, so that the majority of the A-frame, in the form of the beam, can be removed and the weight of the remaining transport unit can be significantly reduced.

[0016] In a further embodiment, the folding spar forms the end of the A-frame spaced from the pivot axis and preferably has connecting means for attaching the guying device. The connecting means are located, in particular, on the side (top) of the A-frame facing the boom. These may be bolt points for attaching retaining rods.

[0017] In a further embodiment, the beam is designed to be removable from the superstructure and the folding beam and transported separately, with the retraction mechanism remaining on the superstructure. For this purpose, the connection between the beam and the folding beam, as well as the connection of the beam to the superstructure, is disconnected.

[0018] In a further embodiment, the fastening means of the superstructure are preferably located in its rear region, and the fastening means of the folding spar are preferably located on the side (underside) of the A-frame facing away from the boom. These may be bolted connections for creating detachable bolted joints. To join the fastening means in this advantageous arrangement, the folding spar simply needs to be pivoted downwards or folded away about a horizontal axis, and then the joined fastening means connected. The remaining connection to the spar can then be released, and the spar removed from the superstructure. Pivoting the folding spar can be accomplished with the aid of an auxiliary crane.

[0019] In a further embodiment, the horizontal axis and the locking mechanism are each provided by releasable bolt connections. The locking mechanism can be engaged along an axis parallel to the pivot axis (locking axis). For this purpose, the frame member and the folding frame member can each have connecting elements, preferably bolted connections. By releasing the connection at the locking axis, the folding frame member can be pivoted relative to the frame member about the pivot axis.

[0020] According to the embodiment of the invention, the fastening means of the folding beam and the superstructure can be brought together by pivoting the folding beam about its axis (pivot axis). After the fastening means have been connected, the connection between the beam and the folding beam can be released along the pivot axis. The pivoting of the folding beam can be carried out with the aid of an auxiliary crane.

[0021] In another embodiment, the upright is longer than the folding upright. This allows most of the A-frame to be disassembled for transport, significantly reducing the weight of the transport unit. Alternatively or additionally, the upright and folding upright can be of essentially the same width. However, the A-frame can also have a basic shape that tapers towards the ends. In this case, the upright and folding upright have essentially the same width, at least at the connection points.

[0022] In a further embodiment, the A-frame is provided to have a frame-shaped structure with two, in particular parallel, longitudinal beams and at least one crossbeam connecting the longitudinal beams, with preferably at least one crossbeam being arranged on the folding beam. The longitudinal beams can alternatively converge towards the folding beam.

[0023] In a further embodiment, the bracing means comprises one or more rigid bracing rods, each pivotably attached to the boom and A-frame.

[0024] Further features, details and advantages of the invention will become apparent from the exemplary embodiments explained below with reference to the figures. The figures show: Figure 1: a generic crawler crane with an A-frame in a side view; Figure 2: the superstructure of an embodiment of the crane according to the invention with a folded-down folding boom in a schematic side view; and Figure 3: the superstructure according to Figure 2 after the removal of the spar.

[0025] The Figure 1Figure 1 shows a typical crawler crane 1 with an A-frame 10 in a side view and has already been described in detail at the beginning. Therefore, repeated explanations are omitted. The mobile crane according to the invention can be such a crawler crane 1, wherein the A-frame 10 is divisible compared to devices of the same type.

[0026] The Figure 2 Figure 1 shows a side view of a section of the superstructure 3 according to a preferred embodiment of the crane 1 according to the invention, which is a crawler crane 1 according to Figure 1The invention concerns the A-frame 10, which is designed to be divisible or disassembled and comprises a beam 14 pivotally connected to the superstructure 3 about a horizontal axis A2 and a folding beam 16 detachably attached to the beam, which forms the end of the A-frame 10 spaced apart from the axis A2. The boom 6, which in the present embodiment is the main boom of the crane 1, is pivotable about a horizontal axis A1 spaced apart from the axis A2.

[0027] The A-frame 10 is adjustable or pivotable via a retraction mechanism, which comprises a retraction winch 20 arranged on the superstructure 3, a first roller assembly 22 arranged at the rear end of the superstructure 3, and a second roller assembly 24 attached to the folding beam 16. A retraction cable 21, which is mounted on the retraction winch 20 so as to be wound and unwound, is guided or wound multiple times around the roller assemblies 22 and 24. By winding the retraction cable 21, the distance between the roller assemblies 22 and 24 can be reduced, thereby pivoting the A-frame 10 backwards / downwards. During unwinding, the reverse movement occurs due to the weight of the boom 6, which is coupled to the A-frame 10 via the retaining rods 12 during operation.

[0028] The A-frame 10, or beam 14, and folding beam 16 can comprise two outer longitudinal beams, with the second roller assembly 24 being mounted between the outer longitudinal beams of the folding beam 16. Beam 14 and folding beam 16 each have connecting elements 26, 27, by which they can be detachably connected or joined to one another. The connecting elements 26, 27 are designed here as bolting points, via which two parallel bolted connections can be made.

[0029] For the removal of the spar 14 from the superstructure 3 for the purpose of transport, the A-frame 10 is pivoted downwards so that it essentially rests against the superstructure 3 (see figure). Figure 2By releasing the upper of the two bolts (locking axis) between beam 14 and folding beam 16, the latter can be pivoted or folded downwards towards the superstructure 3 about the lower bolt connection, which forms a horizontal pivot axis A3. The pivoting of the folding beam 16 about the axis A3 can be carried out using an auxiliary crane. During this process, the second roller assembly 24 moves slightly relative to the first roller assembly 22.

[0030] On the side or underside of the folding spar 16 facing away from the boom 6, fastening elements 18 are designed as bolting points. Similar fastening elements 19 are also arranged at the rear end or in the rear region of the superstructure 3. By pivoting the folding spar 16 about the axis A3, it is rotated towards the superstructure 3, and the fastening elements 18, 19 are brought together, i.e., the bolting points are aligned. By bolting the fastening elements 18, 19, the folding spar 16 is attached to and held in place on the superstructure 3, so that the bolting on the spar (axis A3) can now be released. It is conceivable that the now freed bolts of the released upper bolt connection (locking axis) between spar 14 and folding spar 16 could be used to bolt the fastening elements 18, 19. However, separate bolts can also be used.

[0031] After the folding spar 16 has been mounted on the superstructure 3 and the bolt connection to the spar 14 has been released, the spar 14 can be removed from the superstructure 3. Since the spar 14 itself does not carry any component of the retraction mechanism, the latter remains completely attached to the superstructure 3 and can be transported together with it.

[0032] The Figure 3Figure 3 shows the superstructure 3 in the transport position after the removal of the spar 14, with the folding spar 16 stored at its rear. Since the spar 14 is significantly larger or longer than the folding spar 16, which only forms the upper tip of the A-frame 10, the transport weight of the remaining unit can be considerably reduced by removing the spar 14. The removal process itself is quick and easy, as no complicated parts need to be disassembled. It is also simpler and safer than disassembling the entire A-frame 10, including the retraction mechanism. The spar 14 itself is compact and therefore requires only a small transport volume.

[0033] A method for dismantling the spar 14 to form a lightweight transport unit could comprise the following steps: lowering the A-frame 10, releasing the bracing 12 from the A-frame 10, loosening the upper (bolt) connection between spar 14 and folding spar 16, pivoting the folding spar 16 about the lower bolt connection A3, possibly with the aid of an auxiliary crane, connecting or bolting the pivoted fastening elements 18, 19 of folding spar 16 and superstructure 3, loosening the lower (bolt) connection A3 between spar 14 and folding spar 16, and removing the spar 14 (in particular by loosening the connection at axle A2 with the superstructure 3), possibly with the aid of an auxiliary crane. These steps are carried out in reverse order to assemble the spar 14.

[0034] The A-frame 10 according to the invention can also be easily retrofitted to existing cranes 1. For this purpose, the fastening means 19 for attaching the folding boom 16 only need to be attached to the rear of the superstructure 3 at the suitable location and the second roller assembly 24 mounted on the folding boom 16. List of reference symbols:

[0035] 1 Crane 2 Undercarriage 3 Superstructure 4 Operator's Cab 5 Superstructure Ballast 6 Boom (Main Boom) 7 Load Handling Device (Load Hook) 8 Hoist Rope 9 Hoist Winch 10 A-Frame 12 Guy Wire (Retaining Bars) 14 Beam 16 Folding Beam 18 Folding Beam Fastening Device 19 Superstructure Fastening Device 20 Retractable Winch 21 Retractable Rope 22 First Pulley Set 24 Second Pulley Set 26 Beam Connecting Device 27 Folding Beam Connecting Device A1 Axle A2 Axle A3 Axle

Claims

1. Mobile crane (1), in particular a crawler crane, comprising an undercarriage (2) having a traveling gear, a superstructure (3) supported on the undercarriage (2) in a manner rotatable about a vertical axis, a boom (6) connected in an articulated manner to the superstructure (3) pivotable about a horizontal axis (A1), an A frame (10) connected in an articulated manner to the superstructure (3) pivotable about a horizontal axis (A2) and connected to the boom (6) by means of a guying means (12), and a retraction mechanism by means of which the A frame (10) is pivotable, wherein the A frame (10) is separable and comprises a pole (14) connected in an articulated manner to the superstructure (3) and a folding pole (16) releasably connected to the pole (14), wherein the folding pole (16) and the superstructure (3) each comprise fastening means (18, 19) by means of which the folding pole (16) can be releasably mounted on the superstructure (3) and the folding pole (16) is connected to the pole (14) pivotable about an axis (A3) that is in particular horizontal and is latchable thereto, wherein the fastening means (18, 19) of the folding pole and superstructure (3) can be joined together by pivoting the folding pole (16) about the axis (A3), characterized in that the folding pole (16) can be removed from the pole (14) and can be detachably mounted on the superstructure (3).

2. Crane (1) in accordance with claim 1, characterized in that the components of the retraction mechanism fastened to the A frame (10) are arranged at the folding pole (16).

3. Crane (1) in accordance with claim 2, characterized in that the retraction mechanism comprises a retraction winch (20) arranged on the superstructure (3), a first roller set (22) arranged on the superstructure (3), and a second roller set (24) arranged on the folding pole (16).

4. Crane (1) in accordance with one of the preceding claims, characterized in that the folding pole (16) forms the end of the A frame (10) and preferably has connection means for fastening the guying means (12).

5. Crane (1) in accordance with one of the preceding claims, characterized in that the pole (14) can be removed from the superstructure (3) and from the folding pole (16) and can be transported separately, with the retraction mechanism remaining on the superstructure (3).

6. Crane (1) in accordance with one of the preceding claims, characterized in that the fastening means (19) of the superstructure (3) are preferably arranged in its rear region and the fastening means (18) of the folding pole (16) are arranged on the side of the A frame (10) remote from the boom (6).

7. Crane (1) in accordance with one of the preceding claims, characterized in that the axis (A3) and the latching connection are releasable pin connections.

8. Crane (1) in accordance with one of the preceding claims, characterized in that the pole (14) is longer than the folding pole (16); and / or in that the pole (14) and the folding pole (16) substantially have the same width.

9. Crane (1) in accordance with one of the preceding claims, characterized in that the A frame (10) has a rack-like structure having two side members that are in particular in parallel and having at least one cross member, with at least one cross member preferably being arranged at the folding pole (16).

10. Crane (1) in accordance with one of the preceding claims, characterized in that the guying means (12) comprises one or more rigid guying rods each pivotably fastened to the boom (6) and to the A frame (10).