ARRANGEMENT WITH A BOOM THAT CAN BE ROLLED VIA TWO ROLLER CYLINDERS AND A VEHICLE CRANE EQUIPPED ACCORDINGLY

Description

[0001] The invention relates to a mobile crane comprising a boom that can be rocked at least two rocker cylinders within a vertical rocking plane between a storage position and a working position, wherein the rocker cylinders opposite each other on the rocking plane enclose a spreading angle between their longitudinal axes in the working position and the rocker cylinders engage the boom outside its ends.

[0002] The operational performance of mobile cranes is largely determined by their respective booms. Their typically luffing and telescopic arrangement on a rotating superstructure opens up correspondingly large working areas within which the necessary transfer of loads can take place. The vertical alignment of the boom, which extends essentially horizontally during travel, between its stowed position and an upright working position is achieved via at least one length-adjustable luffing cylinder.

[0003] British Patent Application GB 843 024 A and US Patent 3 045 836 A each describe a mobile crane with a boom featuring two independently operating luffing cylinders. The crane has an undercarriage on which the boom is articulated at its lower end. The luffing cylinders, extending between the boom and the undercarriage, are articulated at their upper ends to a section of the boom. The lower ends of the luffing cylinders are articulated at such a distance from each other on the undercarriage that their longitudinal axes form a spreading angle. The independent control of the two luffing cylinders allows the boom to be pivoted within a vertical plane and also, to a limited extent, horizontally relative to the undercarriage.

[0004] The A-shaped, splayed position of the two luffing cylinders relative to each other is based on the desire for a range of aligning options for the boom relative to the undercarriage of the mobile crane, extending beyond mere vertical swiveling. Besides the resulting limited lateral swiveling of the boom, its design means that in its stowed position, the boom rests on the two luffing cylinders, which are oriented perpendicular to the plane of the luffing motion. This, particularly during operation, negates the advantage of compact vehicle dimensions. Given these observations, the known arrangement still offers room for improvement. In the illustrated horizontal stowed position of the telescopic boom, the luffing cylinders form a tilt angle of 0° with a vertical axis.

[0005] US patent 2,996,196 discloses another mobile crane with a main boom and a luffing boom. In this design, the main boom consists of two main boom arms mounted together at the upper end of a main boom head, extending from there in a V-shape towards the vehicle. The lower ends of each of the two main boom arms are mounted on the vehicle so that they can be tilted about horizontal axes. The main boom arms are telescopically extendable in opposite directions to allow the main boom to tilt laterally to the right or left. A single telescopic luffing boom is provided for tilting the two main boom arms; this boom is also pivotally attached to the main boom head and to a pivoting frame on the vehicle. The two main boom arms and the luffing boom thus form a tripod extending from the main boom head.During the luffing motion of the two main boom arms, they are subjected to compressive stress, and the luffing boom is subjected to tensile stress. The U-shaped swivel frame is pivotally mounted on the vehicle along the horizontal axes of the main boom arms. Furthermore, the swivel frame can be pivoted from an upright operating position to a largely horizontal transport position via a hydraulic cylinder, which is also supported by the vehicle. Together with the swivel frame, the two main boom arms and the luffing boom are thus pivoted from the operating position to the transport position by the additional hydraulic cylinder.

[0006] Furthermore, utility model DE 20 2005 015 044 U1 already describes a mobile crane with a road-travelable undercarriage on which a superstructure pivoting about a vertical axis is mounted. A telescopic boom with a base box and several telescoping inner boxes is mounted on the superstructure so that it can be rocked about a horizontal axis. The raising and lowering of the telescopic cylinder is effected by two parallel hydraulic rocker cylinders arranged at a distance from each other. These cylinders are supported at their lower ends by the superstructure and are pivoted at their upper ends approximately in the area of ​​the middle and on the underside of the base box of the telescopic boom.

[0007] Furthermore, patent application WO 01 / 14239 A1 discloses a mobile crane according to the preamble of claim 1 in the form of a mobile container stacker, also known as a reach stacker. Such container stackers are used for container handling, for example, in port areas. The container stacker essentially consists of a ring-shaped undercarriage with six rubber-tired twin wheels evenly distributed around its circumference, each of which is steerable through 360°. A telescopic boom is mounted on the undercarriage, which can be hydraulically extended from a lowered rest position about a horizontal luffing axis into a desired working position via two luffing cylinders. A load-handling device in the form of a spreader is arranged at the end of the telescopic boom for handling the containers. The telescopic boom consists, in the usual manner, of a base box and several inner boxes that can be extended and retracted therein.The rocker cylinders are supported at their lower ends centrally against opposite edges of the undercarriage and are hinged at their upper ends laterally in the area of ​​the upper end of the base frame. Viewed longitudinally along the telescopic boom and from the boom itself, the two rocker cylinders form a roughly V-shaped profile in the rest position and in each of the working positions. In the rest position, i.e., when the telescopic boom is lowered, the rocker cylinders form an angle of approximately 45° with a vertical line.

[0008] A mobile crane with a telescopic boom that can be tilted from a horizontal storage position to an erected working position by means of a single rocker cylinder is also known from US patent 3,792,778 A. In the storage position, the telescopic boom is additionally supported by two outriggers on the mobile crane. These outriggers are oriented in a V-shape relative to the telescopic boom when viewed along the longitudinal axis of the mobile crane. In a horizontal storage position of the telescopic boom, the outriggers form an angle of inclination of 45° with a vertical axis.

[0009] Furthermore, US patent 6,089,388 A discloses another mobile crane with a telescopic boom that can be tilted from a horizontal storage position to an erected working position by means of two parallel rocker cylinders. In the storage position of the telescopic boom, the rocker cylinders form an angle of inclination of 75° with a vertical line.

[0010] The present invention is therefore based on the objective of further developing previously known vehicle cranes with luffing booms in such a way that, in particular, a design that is as compact as possible can be achieved in the stowed position of the boom.

[0011] According to the invention, the solution to this problem consists of a mobile crane with the features of claim 1. Advantageous embodiments of the invention are specified in dependent claims 2 to 13.

[0012] The invention proposes that in a mobile crane with a boom that can be rocked between a storage position and a working position via at least two rocker cylinders within a vertical rocking plane, wherein the rocker cylinders opposite each other on the rocking plane enclose a spreading angle between their longitudinal axes in the working position and the rocker cylinders act on the boom outside its ends, wherein in the preferably horizontal storage position of the boom the longitudinal axis of a rocker cylinder projected onto the rocking plane and an upward direction extending within the rocking planeThe vertical direction encloses an angle of inclination between itself, in the storage position of the boom a design that is as compact as possible and in particular a stable and self-contained arrangement that is as possible, is achieved by the fact that the boom is mounted on a base frame in a rocking manner, wherein the base frame has lower bearing arrangements designed as cross or ball joints, via which the rocker cylinders are articulatedly supported on the base frame, and wherein the boom has upper bearing arrangements designed as cross or ball joints, via which the rocker cylinders are articulatedly supported on the boom, and that at least one of the bearing arrangements can be variably positioned along a path running perpendicular to the rocker plane, wherein the path has a straight or curved course at least in sections.

[0013] The resulting adjustability of at least one of the two lower bearing arrangements and / or upper bearing arrangements allows for a corresponding change in the spread angle between the rocker cylinders, whereby the spread angle between them can be directed downwards (A-shape) or upwards (V-shape). In other words, from a frontal perspective, the two rocker cylinders can form either an A-shape or a V-shape. In the V-shape, the upper ends of the rocker cylinders on the boom are further apart, perpendicular to the rocking plane, than their opposite lower ends on the base frame. The opposite is true for the A-shape. The V-shape allows for a more compact design closer to the lower bearing arrangements of the rocker cylinders.

[0014] By means of the aforementioned relocatability of the lower and / or upper bearing arrangements, the stabilizing effect of the boom against lateral influences, resulting from the A-shaped or V-shaped position, can be advantageously increased as needed. Furthermore, relocating the bearing arrangement of at least one rocker cylinder allows for even more compact dimensions of the arrangement according to the invention. For example, the at least one bearing arrangement can preferably be moved closer to the boom in its stowed position to reduce the lateral dimensions of the arrangement, at least temporarily. The simultaneously decreasing spread angle may reduce the lateral stability of the boom, but this is irrelevant, especially in its stowed position.

[0015] Furthermore, the sliding and / or rotating mechanisms allow for changes to the bearing position of the rocker cylinders relative to a pivot joint that supports the boom on the base frame. This enables variations in the triangle formed by the ends of the rocker cylinders on the base frame and the boom, as well as the pivot joint of the boom on the base frame. These adjustments allow for improved force transmission, thus optimizing the components on the rocker cylinders, base frame, and boom.

[0016] Advantageously, the design provides that in the boom's stowed position, the tilt angle is between 60° and 120°, preferably between 80° and 100°, and particularly preferably between 90° and 97°. In other words, the two rocker cylinders are inclined relative to the vertical direction in a side view of the boom as soon as the boom is in its stowed position and the spread angle in the boom's working position is between 2° and 30°. According to the fundamental concept of the invention, in the boom's stowed position, the tilt angle of the rocker cylinders relative to the vertical direction is between 80° and 100°. This allows each rocker cylinder to extend not only to +10° above a horizontal but also to -10° below it when the boom is in its stowed position.Depending on the arrangement of the lower end connections of the rocker cylinders and the pivoting bearing, the boom can also be inclined upwards or downwards in its storage position with respect to the horizontal, as well as extend parallel to it.

[0017] Depending on the design, it is considered advantageous if the rocker cylinders can extend almost parallel to the horizontal in the stowed position of the boom, with their angle of inclination relative to the vertical direction preferably being from 90° to 97°.

[0018] In this context, the downward or upward opening angle in the working position of the boom ranges from 2° to 30°.

[0019] In connection with the present invention, the feature relating to the rocker cylinders that engage the boom outside its ends is understood to mean that the rocker cylinders engage in a region on the boom or the base box which, viewed in the longitudinal direction of the boom or a base box of the boom, is spaced at least 10%, preferably at least 20%, particularly preferably at least 30% of the total length of the boom or base box from both the upper and the lower end of the boom or base box. Overall, the rocker cylinders thus engage the boom or base box more centrally than at its head end.

[0020] The resulting advantage lies in the fact that the boom, supported by the rocker cylinders, is no longer raised along its entire length when retracted, as was previously the case, once it is in its storage position. Compared to the previous vertical or parallel orientation of the rocker cylinders in the storage position, the now possible near- or exactly horizontal alignment of the rocker cylinders requires significantly less installation space below the boom in its storage position. According to the invention, the orientation of each individual rocker cylinder, which is now always inclined towards the upward direction in the storage position of the boom, ensures that the position of its previously superimposed end connections is offset relative to each other due to the horizontal and vertical components resulting from the inclination.Since the upper end connection of each inclined rocker cylinder pivots on a circular path around its lower end connection, the boom can be aligned correspondingly lower in its storage position.

[0021] In a further development of the previously described displacement capability, it is considered particularly advantageous if the lower and / or upper bearing arrangements of the rocker cylinders can be simultaneously displaced in opposite directions, either towards or away from each other, along their respective paths. This allows the inclination of both rocker cylinders to be changed to the same extent, ensuring that their connection to the boom always remains within the rocker plane, while the spread angle between the longitudinal axes of the rocker cylinders is altered. This effectively prevents any undesired lateral displacement of the boom when the bearing arrangement(s) are moved.

[0022] In contrast, the value of the downward or upward opening spread angle in the storage position of the boom can particularly preferably be from 0° to 45° or from 0° to 6°, so that an at least approximately parallel alignment of the rocker cylinders is made possible, for example, during the operation of a crane vehicle according to the invention.

[0023] Even if the base frame is a component that can be connected to, for example, a section of a mobile crane, it is considered advantageous if the base frame itself is part of a superstructure of a mobile crane that can rotate relative to the undercarriage. Naturally, the base frame itself can be a superstructure, or be designed as one. Alternatively, the base frame itself can be part of the undercarriage of a mobile crane. Of course, in this case as well, the base frame itself can be such an undercarriage, or be designed as one.

[0024] With the vehicle crane according to the invention now presented, an extremely compact design can be achieved, particularly in the stowed position of its boom. This is made possible by the inclined orientation of the rocker cylinders in the stowed position of the boom. In combination with the sliding bearing arrangements, the lateral stability of the boom, already inherent due to the A-shaped orientation of the rocker cylinders relative to each other, can be further increased, which can have a significant influence on the design of the pivoting boom bearing. This pivoting bearing, in combination with rocker cylinders that are generally aligned parallel to each other, is usually designed so that it can absorb the lateral forces acting on the boom, especially when in the working position, and transfer them, for example, to a vehicle crane equipped with it.Due to the A-shaped or V-shaped orientation of the two rocker cylinders, forming a statically advantageous and extremely stable triangle (at least in the boom's working position), the forces acting laterally on the boom, particularly in the A-shape, can now be at least partially absorbed and transferred via the rocker cylinders. This significantly simplifies the requirements for the boom's pivoting bearing and the base frame itself regarding their capacity to absorb such forces. As a result, the pivoting structural mounting of the boom and base frame can, for example, be designed to be more compact and streamlined.

[0025] In a preferred embodiment, the boom is a telescopic boom with a base box and extendable inner boxes. The rocker cylinders then engage with the base box of the boom.

[0026] Two rocker cylinders are particularly advantageous.

[0027] Furthermore, the mobile crane includes a chassis.

[0028] It is particularly advantageous, especially in a design of the mobile crane with a rubber-tired and road-travelable undercarriage, that in the stowed position of the boom the boom rests on the undercarriage.

[0029] An embodiment of the invention is explained in more detail below. The following description shows: Figure 1 the schematic representation of a vehicle crane according to the invention in a perspective view, Figure 2 the schematic representation of a section of a vehicle crane according to the invention Figure 1 in a perspective style, Figure 3 the excerpt from Figure 2 in an alternative form of presentation in a schematic representation of his view, Figure 4the schematic representation of a vehicle crane according to the invention in a frontal view in a first embodiment, Figure 5 the schematic representation of a vehicle crane according to the invention in a frontal view in a further embodiment, Figure 6 The schematic representation of a vehicle crane according to the invention in a configuration as a mobile crane.

[0030] Figure 1A vehicle crane 1 according to the invention can be seen in the illustration. By way of example, this is a vehicle crane 1 with a tracked undercarriage, which has a chassis 2 equipped with two parallel, spaced-apart crawler tracks 2a, 2b. Of course, a wheeled chassis, not shown in detail here, could also be used. A superstructure 3 with a driver's cab 3a and a boom 4 is rotatably mounted on the chassis 2. The boom 4 is designed as a telescopic boom in the usual manner, consisting of an outer base section 4a and inner sections 4b that can be extended or retracted hydraulically. The boom 4 is pivotably mounted on the superstructure 3 at its lower end, so that it can be tilted between a horizontal storage position P1 (only indicated here) and the upright working position P2 shown here.The inclination of the boom 4 relative to the horizontal in the working position P2 shown here is to be regarded as exemplary, since it can of course also assume all other values ​​that deviate from the orientation of the boom 4 in its storage position P1.

[0031] The boom 4 can only be tilted within a vertical tilting plane WE, the orientation of which can be changed as needed by rotating the superstructure 3 relative to the undercarriage 2 in a manner not shown in detail. The drive required for tilting and supporting the boom 4 is provided by two, preferably exactly two, tilting cylinders 5a, 5b, located opposite each other on the tilting plane WE. The two tilting cylinders 5a, 5b are arranged such that their longitudinal axes x1, x2, in the working position P2 of the boom 4 shown here, form a downward-opening spread angle α between them. Furthermore, the tilting cylinders 5a, 5b act on the boom 4 outside its ends.

[0032] Figure 2 shows an arrangement 10 according to the invention, which incorporates some of the features already described in Figure 1The assembly 10 comprises the parts of the mobile crane 1 shown. Specifically, the assembly 10 has the boom 4, reduced here to its base for clarity only, and the two luffing cylinders 5a, 5b, all of which are supported at their lower ends on a base frame 11 of the assembly 10. The boom 4 is mounted on the base frame 11 so that it can pivot about a horizontal axis S, with the two luffing cylinders 5a, 5b being pivotally supported on the base frame 11. For this purpose, two lower bearing arrangements 12a, 12b are shown on the base frame 11 and two upper bearing arrangements 13a and 13b are shown on the boom 4, each of which is located on the two luffing cylinders 5a, 5b. Each of these bearing arrangements 12a, 12b; 13a, 13b is designed in an unspecified manner as a cross or ball joint to allow the two rocker cylinders 5a, 5b the necessary freedom of movement when rocking the boom 4.

[0033] Furthermore, regarding the rocker cylinders 5a, 5b from the Figure 1 It can be seen that the rocker cylinders 5a, 5b, designed as hydraulic cylinders, are preferably articulated to the base box 4a outside its upper and lower ends at the upper ends of their piston rods. The two rocker cylinders 5a, 5b engage the base box 4a approximately in the middle of an upper half of the base box 4a. Preferably, the two rocker cylinders 5a, 5b engage the base box 4a of the boom 4 in a region which, viewed longitudinally, is spaced at least 10%, preferably at least 20%, and particularly preferably at least 30% of the total length of the base box 4a from both the upper and lower ends of the base box 4a.

[0034] In principle, it is possible that the basic frame 11 shown here is part of the superstructure 3 of the mobile crane 1, which is rotatable relative to the undercarriage 2. Figure 1or the superstructure 3 itself. Alternatively, it is conceivable that the aforementioned base frame 11 is part of the undercarriage 2 of the mobile crane 1. Figure 1 or the undercarriage 2 itself.

[0035] The Figure 3 is the arrangement 10 from the Figure 2This can now be seen in a side view. The horizontal storage position P1 of the boom 4 – reduced here to its base for clarity – is shown, while its working position P2 is indicated by dashed lines. In its storage position P1, the boom 4 extends, for example, parallel to a horizontal direction X, while the two rocker cylinders 5a and 5b, which are opposite each other on the rocker plane WE and spaced apart in a transverse direction Y, are shown lying on top of each other. Consequently, only the rocker cylinder 5b in the foreground is visible, while the rocker cylinder 5a behind it is obscured. The change in the inclination of the rocker cylinders 5a and 5b in the working position P2 of the boom 4 is also indicated by the use of dashed lines.

[0036] As can be seen, the longitudinal axis x1, x2 of the rocker cylinders 5a, 5b, projected onto the rocker plane WE, and an upward direction Z extending within the rocker plane WE orthogonally to the horizontal direction X, form an angle of inclination b between themselves as soon as the boom 4 is in its storage position P1. In other words, the two rocker cylinders 5a, 5b are inclined relative to the upward direction Z in the storage position P1 of the boom 4. In this case, said angle of inclination b in the storage position P1 of the boom 4 is approximately 75°. Depending on the configuration of the arrangement 10, the angle of inclination b in the storage position P1 of the boom 4 can also be so large that the rocker cylinders 5a, 5b can preferably extend parallel to and below the horizontal direction X, in a manner not shown here.

[0037] Figure 4 illustrates the structure of arrangement 10 from the Figure 2 and 3based on an alternative embodiment. As can be seen in the view of arrangement 10 shown here, the upper bearing assemblies 13a, 13b of the two rocker cylinders 5a, 5b can of course also be arranged laterally on the base of the boom 4. In this case, the two lower bearing assemblies 12a, 12b are displaceable along a path P perpendicular to the rocker plane WE in a manner not shown in detail. This path can have a straight and / or curved course, at least in sections, and is shown here as curved by way of example. It is provided that the two bearing assemblies 12a, 12b can be displaced simultaneously along the path P in opposite directions R1, R2 towards or away from each other. Due to the movable design of the bearing arrangements 12a, 12b, it is possible to change the spreading angle a enclosed between the longitudinal axes x1, x2 of the two rocker cylinders 5a, 5b.The downward-facing spread angle a, open towards the base frame 11, can be changed in the storage position P1 and / or in the working position P2 of the boom 4. The spread angle a can take on values ​​from greater than 0° to 45°, preferably being greater in working position P2 than in the storage position P1 of the boom 4. For example, the spread angle a in storage position P1 of the boom 4 can be from 0° to 6°, so that the two rocker cylinders 5a, 5b run almost parallel to each other, in order to achieve, for example, the most compact dimensions possible during the movement of the vehicle 1 thus equipped.

[0038] Figure 5Figure 10 illustrates a further alternative embodiment of the arrangement according to the invention. Here, the lower bearing arrangements 12a, 12b are positioned relative to the upper bearing arrangements 13a, 13b such that the spreading angle a enclosed between the two rocker cylinders 5a, 5b now opens upwards. In other words, the arrangement of the two rocker cylinders 5a, 5b tapers to a point towards the base frame 11. In this embodiment, the upper bearing arrangements 13a, 13b are also adjustable in their respective positions along a path P, resulting in a corresponding change in the upwardly open spreading angle a.

[0039] It is of course conceivable that the upper and lower bearing arrangements 12a, 12b; 13a, 13b can be moved so that the spreading angle a can be opened upwards or downwards as required.

[0040] In the Figure 6Figure 1 shows a schematic representation of a vehicle crane 1 according to the invention in a configuration as a mobile crane capable of traveling on public roads, which accordingly has a chassis 2 with rubber-tired wheels 2c distributed on, for example, four axles. A superstructure 3, pivotable about a vertical axis of rotation, with the luffing boom 4, is mounted on the chassis 2 in the usual manner. It is evident that in the already shown figure, Figure 3 In the essentially horizontal storage position P1 of the boom 4, as described, the boom is supported on the undercarriage 2 by a support 14. For this purpose, the support 14 extends vertically from the upper side of the undercarriage 2 towards the underside of a base box 4a of the boom 4 and comes into contact there. Reference symbol list

[0041] 1 Vehicle crane 2 Undercarriage 2a Crawler track 2b Crawler track 2c Wheel tires 3 Superstructure 3a Operator's cab 4 Boom 4a Base box 4b Inner box 5a Lugger cylinder 5b Lugger cylinder 10 Arrangement 11 Base frame 12a Bearing arrangement, bottom 12b Bearing arrangement, bottom 13a Bearing arrangement, top 13b Bearing arrangement, top 14 Support a Spread angle b Tilt angle PP path P1 Storage position P2 Working position R1 Direction R2 Direction S Swivel axis WE Lugger plane x1 Longitudinal axis x2 Longitudinal axis X Horizontal direction Y Transverse direction Z Vertical direction

Claims

1. Mobile crane (1) with a boom (4) that can be luffed via at least two luffing cylinders (5a, 5b) within a vertical luffing plane (WE) between a storage position (P1) and a working position (P2), wherein the luffing cylinders (5a, 5b) opposite each other on the luffing plane (WE) enclose a spread angle (a) between their longitudinal axes (x1, x2) in the working position (P2) and the luffing cylinders (5a, 5b) engage with the boom (4) outside its ends, wherein in the storage position (P1) of the boom (4) the longitudinal axis (x1, x2) of a luffing cylinder (5a, 5b) projected onto the luffing plane (WE) and a vertical direction (Z) extending within the luffing plane (WE) enclose an inclination angle (b) between themselves, characterised in that the boom (4) is mounted on a main frame (11) in a luffable manner, wherein the main frame (11) has lower bearing arrangements (12a, 12b) designed as either a cross or ball joint, by means of which the luffing cylinders (5a, 5b) are supported in an articulated manner on the main frame (11), and wherein the boom (4) has upper bearing arrangements (13a, 13b) designed as either a cross or ball joint, by means of which the luffing cylinders (5a, 5b) are supported in an articulated manner on the boom (11), and in that at least one of the bearing arrangements (12a, 12b; 13a, 13b) is variably positionable along a path (P) perpendicular to the luffing plane (WE), wherein the path (P) has a straight or curved profile at least in portions.

2. Mobile crane (1) according to claim 1, characterised in that in the storage position (P1) of the boom (4) the inclination angle (b) is from 60° to 120°, preferably from 80° to 100°, particularly preferably from 90° to 97°.

3. Mobile crane (1) according to claim 1, characterised in that the bearing arrangements (12a, 12b; 13a, 13b) can be moved simultaneously in opposite directions (R1, R2) towards each other or away from each other along the path (P).

4. Mobile crane (1) according to any of the preceding claims, characterised in that the spread angle (a) between the longitudinal axes (x1, x2) of the two luffing cylinders (5a, 5b) in storage position (P1) and / or in working position (P2) of the boom (4) is changeable.

5. Mobile crane (1) according to claim 4, characterised in that the spread angle (a) in the working position (P2) of the boom (4) is greater than 0° to 45°, preferably from 2° to 30°.

6. Mobile crane (1) according to claim 4 or 5, characterised in that the spread angle (a) in the storage position (P1) is from 0° to 45° or from 0° to 6°.

7. Mobile crane (1) according to any of claims 1 to 6, characterised in that the main frame (11) is part of a superstructure (3) of a mobile crane (1) which superstructure is rotatable relative to a substructure (2), or is the superstructure (3) itself.

8. Mobile crane (1) according to any of claims 1 to 5, characterised in that the main frame (11) is part of a substructure (2) of a mobile crane (1), or is the substructure (2) itself.

9. Mobile crane (1) according to any of the preceding claims, characterised in that the boom (4) is a telescopic boom having a main box (4a) and telescoping inner boxes (4b).

10. Mobile crane (1) according to claim 9, characterised in that the luffing cylinders (5a, 5b) engage with the main box (4a) of the boom (4).

11. Mobile crane (1) according to any of the preceding claims, characterised in that exactly two luffing cylinders (5a, 5b) are provided.

12. Mobile crane (1) according to any of the preceding claims, characterised in that the mobile crane (1) comprises a substructure (2).

13. Mobile crane (1) according to claim 1 or 2, characterised in that in the storage position (P1) of the boom (4), the boom (4) rests on the substructure (2).