Mobile crane and method for bringing one into a transport state

Abstract

The invention relates to a mobile crane comprising an undercarriage with a wheeled chassis, a superstructure rotatably mounted on the undercarriage with a boom pivotally mounted about a horizontal luffing axis, and at least one hydraulic luffing cylinder for raising and lowering the boom, which is pivotally mounted on the superstructure about a horizontal pivoting axis and articulated to the boom via a connecting element. According to the invention, the mobile crane includes a holding device arranged on the undercarriage for storing the luffing cylinder in a transport position for road travel, which comprises a receiving element to which the connecting element of the luffing cylinder can be detachably connected, and an adjustment device by means of which the holding device can be moved relative to the undercarriage along a longitudinal direction by extending and retracting the received luffing cylinder.The invention further relates to a method for bringing the mobile crane according to the invention into a transport state.

Description

The present invention relates to a mobile crane according to the preamble of claim 1 and to a method for bringing such a mobile crane into a transport state.Mobile cranes are moved on public roads. In this case, the rules apply for the road traffic permission order (StVZO), which define, inter alia, the permissible axle load and the permissible total load of a vehicle. The height of these loads determines which permits can be granted for the vehicle. For large and heavy mobile cranes, general permission for operation is often no longer possible, as a result of which special permissions have to be obtained for each individual journey and various requirements have to be fulfilled.The heavier the overall vehicle, the more difficult, more expensive and cost-intensive the determination of the predefined travel path is configured. In addition, the maximum permissible load of an axle is limited, wherein these specifications can be different in each country (in Germany, the maximum axle load is, for example, 12 tons). In the case of larger mobile cranes, the vehicle components such as, for example, the superstructure are already optimized with regard to the load distribution. If the superstructure is not to be removed from the undercarriage for road travel, its weight represents a decisive factor for the position of the center of gravity and thus for the load distribution of the mobile crane.A mobile crane of the generic type is known from DE 10 2020 106 900 B3.The object of the present invention is therefore to further optimize the load distribution of mobile cranes without having to completely break down their superstructures for road travel and transport them separately.According to the invention, this object is achieved by a mobile crane having the features of claim 1 and by a method according to claim 12. Advantageous embodiments of the invention are evident from the dependent claims and the following description.Accordingly, a mobile crane is proposed which comprises a undercarriage with a wheel chassis and an superstructure mounted rotatably on the undercarriage. The superstructure comprises a boom, in particular a telescopic boom, mounted pivotably about a horizontal luffing axis, and at least one hydraulic luffing cylinder for swinging up and down the boom. The at least one luffing cylinder is mounted on the superstructure so as to be pivotable about a horizontal pivot axis and in particular running parallel to the boom rocker axis and is connected to the boom in an articulated manner via a connecting means. For the sake of simplicity, only the luffing cylinder (singular) is mentioned below-but the at least one luffing cylinder should always be meant unless stated otherwise.The mobile crane is moved on public roads. In this case, its superstructure is not completely removed. Certain components, such as parts of a undercarriage support and / or superstructure ballast elements, can optionally be removed for transport and moved separately. It can be provided that the mobile crane is moved together with its boom.According to the invention, the mobile crane comprises a holding device arranged on the undercarriage for storing the luffing cylinder. The latter can be released from the boom for road travel and stored on the holding device in a transport state. For this purpose, the holding device comprises a receiving means, with which the connecting means of the luffing cylinder can be detachably connected. To move the luffing cylinder into the transport state, its connecting means, in particular a lug or fork with bolt receptacle(s) formed on the piston rod or on the cylinder housing, is released from the articulation point on the boom and connected, in particular bolted, to the receiving means of the holding device. As a result, the luffing cylinder is securely accommodated in or on the holding device.The holding device further comprises an adjusting device, by means of which the holding device can be moved along a longitudinal direction of the undercarriage by retracting and extending the accommodated luffing cylinder relative to the undercarriage. The holding device thus makes it possible to move the luffing cylinder in a controlled manner in a state fastened to the receiving means and with reduced friction (i.e. to move the piston rod out of the cylinder housing of the luffing cylinder). The holding device moves along the longitudinal axis of the undercarriage, in particular on an upper side of the undercarriage.The luffing cylinder has a cylinder housing and a piston mounted displaceably therein and having a piston rod. The connecting means is preferably located at a free end of the piston rod, while the cylinder housing can be mounted on the superstructure so as to be pivotable about the pivot axis of the luffing cylinder via a further connecting means.The luffing cylinder comprises a piston chamber and an annular chamber. In the retracted state, the piston chamber is very small, while the volume of the annular chamber is at most large. The volumes of hydraulic oil absorbed also behave, which have a considerable intrinsic weight at the respective amounts. It should be noted here that the volume of hydraulic oil in the piston chamber is significantly larger than in the annular chamber. The luffing cylinder consequently has a substantially lower weight in the retracted state than in the extended state, on account of the hydraulic oil accommodated in the larger piston space in the extended state.By securing the luffing cylinder on the holding device and controlled deployment thereof, the weight of the luffing cylinder is displaced in the direction of the vehicle front. The hydraulic oil received in the luffing cylinder is additionally taken from a hydraulic tank which, in typical mobile cranes, is located further back on the superstructure. As a result, when the luffing cylinder is extended, the total center of gravity of the mobile crane is displaced further forward, so that in the transport state a better weight distribution is obtained, in which the load is distributed more uniformly to the wheel axles. As a result, it is possible to meet specifications for maximum axle loads in road traffic even in the case of large or heavy mobile cranes without having to completely disassemble the heavy luffing cylinder or other heavy crane components for transport.In the present case, the transport state denotes a state in which the luffing cylinder is connected to the holding device and extended via its connecting means.In one possible embodiment, it is provided that the undercarriage comprises a boom receptacle on which the boom can be placed for the road transport. This can be a storage rack arranged in a front region of the undercarriage. This can be arranged on or on or behind an undercarriage driver's cabin.Preferably, the undercarriage has an adjusting surface on an upper side, along which the holding device moves when the luffing cylinder accommodated in the holding device is moved in or out. During the transport of the road or in the case of a boom placed on the boom receptacle, the adjusting surface is located in particular below the boom. The adjustment surface can be located between a passenger cabin and a swivel ring, above which the upper cabin is rotatably mounted on the lower cabin. The adjustment region is in particular free of disturbing components and edges, so that the holding device can be adjusted undisturbed.In a further possible embodiment, it is provided that at least one guide device is arranged on the adjustment surface, along which the holding device is movable via the adjustment device. This enables a controlled, guided movement of the holding device when the luffing cylinder secured thereto is retracted and extended. The guide means may comprise one or more guide rails which allow rolling or sliding movement of the holding device. The adjustment device can thus be mounted in particular displaceably or movably along the guide device. The guide device extends in particular along the longitudinal direction of the undercarriage.In a further possible embodiment, it is provided that the adjusting device comprises rollers (in particular at least three and preferably four rollers), by means of which the holding device can be moved on an upper side of the undercarriage. Preferably, the holding device is movable via the rollers on the previously described adjustment surface. It can be provided that the rollers roll directly on the top side of the undercarriage, i.e. that no guide device is present. In this case, the guidance takes place via the rigid luffing cylinder and its mounting on the superstructure which is rotationally rigid with respect to a vertical axis. Alternatively, it can be provided that the rollers are mounted on or in guide rails running along the upper side of the undercarriage, so that the holding device is moved in a defined manner.In an alternatively possible embodiment, it is provided that the adjusting device comprises slide bearings, by means of which the holding device is displaceable on an upper side of the undercarriage. Preferably, the holding device is displaceable on the previously described displacement surface via the slide bearings. It can be provided here that the slide bearings bear directly on the upper side of the undercarriage, i.e. that no guide device is provided. In this case, the guidance takes place via the rigid luffing cylinder and its mounting on the superstructure which is rotationally rigid with respect to a vertical axis. Alternatively, it can be provided that the slide bearings are mounted slidingly on or in guide rails running along the upper side of the undercarriage, so that the holding device is displaced in a defined manner.In a further possible embodiment, it is provided that the holding device does not comprise its own drive for moving the holding device along the undercarriage longitudinal direction. The movement of the holding device is therefore effected exclusively by the retraction and extension of the luffing cylinder, which for this purpose also remains connected to the hydraulic system of the mobile crane in a state mounted on the holding device. This results in a simpler and weight-saving construction of the holding device.In a further possible embodiment, it is provided that the connecting means of the luffing cylinder comprises a bolt receptacle. Preferably, the connecting means is designed as a lug arranged on the piston rod and having a bolt receptacle (i.e. the cylinder housing is connected in an articulated manner to the superstructure and the piston rod is extended and retracted relative to the superstructure). Alternatively, the tongue could be formed on the cylinder housing (i.e. the piston rod would in this case be articulated to the superstructure and the cylinder housing would be extended and retracted relative to the superstructure). Alternatively, the connecting means could be designed as a fork with two bolt receptacles.Preferably, the receiving means comprises a bolt or bearing body which can be received in the bolt receiver of the luffing cylinder. The latter can represent a type of compensating body which is dimensionally adapted to the bolt receptacle of the luffing cylinder. The forces to be transmitted at the connection to the luffing cylinder are significantly smaller in the transport state than the forces to be transmitted in the working state (state in which the luffing cylinder is articulated on the boom).Therefore, no solid bolt needs to be used for the connection between the receiving means and the connecting means in the transport state. The bearing body can therefore consist of a lighter material or be designed with significantly less material outlay.Preferably, the bolt or bearing body is mounted on the receiving means in a rotationally fixed manner with respect to a luffing cylinder longitudinal axis or with respect to the undercarriage rotational axis. In other words, when the luffing cylinder is retracted and extended, its piston rod cannot rotate about its longitudinal axis relative to the cylinder housing. This rotationally fixed securing of the luffing cylinder on the holding device results in a controlled retraction and extension.In a further possible embodiment, it is provided that the luffing cylinder comprises a cylinder housing and a piston rod, wherein the receiving means is designed such that, when the luffing cylinder received in the holding device is extended, a rotation of the piston rod about its longitudinal axis relative to the cylinder housing is blocked.In a further possible embodiment, it is provided that the holding device comprises a carrier plate on which the adjusting device is arranged, and a carrier connected to the carrier plate on which the receiving means is arranged. The carrier is preferably rigid and can have any desired shape. Preferably, the carrier is designed such that the receiving means is in a position elevated relative to the carrier plate. As a result, the luffing cylinder does not have to be lowered to such an extent. A plurality of rollers can be rotatably mounted on the carrier plate or a plurality of slide bearings can be arranged.In a further possible embodiment, it is provided that the mobile crane comprises two luffing cylinders for tilting up and down the boom. This is the case in particular in the case of larger mobile cranes with high load carrying capacity, in which the telescopic jib requires two luffing cylinders which are aligned parallel to one another.In this case, the holding device comprises two receiving means for releasable connection to the connecting means of a respective luffing cylinder, so that each of the luffing cylinders is secured to a receiving means of the holding device in the transport state. For displacing the center of gravity, in this case both luffing cylinders are extended simultaneously and uniformly.Preferably, the holding device comprises a carrier plate with the adjusting device and a carrier connected to the carrier plate and in particular rigid or rigid, on which the receiving means are arranged. The carrier, which forms a cross member, rigidly connects the receiving means to one another and to the adjusting device, so that a stable mounting of the luffing cylinders results. Preferably, the receiving means are arranged laterally next to the carrier plate, wherein the carrier in particular protrudes laterally beyond the carrier plate.In the embodiments described above, instead of a carrier plate, a carrier frame could alternatively be provided, on which the adjustment device is arranged and to which the carrier is connected.On the carrier or alternatively on the carrier plate, stop elements for fastening a stop means of a lifting device can be provided in order to be able to lift the holding device to the undercarriage.In principle, the holding device could remain on the undercarriage in the working state and be locked to the undercarriage, for example, via a securing mechanism. Alternatively, it can be provided that the holding device for the working operation is removed from the top side of the undercarriage and placed on the floor, for example, or stored in a holder provided separately for this purpose, which can be arranged in particular on the mobile crane.In a further possible embodiment, it is provided that the mobile crane comprises a hydraulic circuit connected to the luffing cylinder and having a hydraulic tank, wherein the hydraulic tank is preferably arranged in a rear region of the superstructure. This has the advantage that when the luffing cylinder is extended, the hydraulic oil additionally received in its piston chamber is displaced from the rear hydraulic tank forwards into the luffing cylinder, which moves the center of gravity further forwards.The present invention further relates to a method for bringing the mobile crane according to the invention into a transport state. This results in the same advantages and properties as in the mobile crane according to the invention. The mobile crane used for the method may be configured according to any of the embodiments described above, in any combination. Therefore, repetitive description will be omitted.The method comprises the following steps:releasing the luffing cylinder at its connecting means from the boom, wherein the luffing cylinder remains connected to the superstructure at its pivot axis,lowering the luffing cylinder to the receiving means of the holding device, for example by means of an auxiliary crane, a mobile mounting device or a device remaining on the mobile crane,connecting, in particular bolting, connecting and receiving means,extending the luffing cylinder, wherein the holding device moves relative to the undercarriage along the undercarriage longitudinal axis via its adjusting device. The center of gravity of the mobile crane is displaced forward.The working state is essentially produced by carrying out these steps in the reverse sequence (retraction of the luffing cylinder, release from the holding device, lifting of the connecting means to the boom and establishing the connection therewith, optionally removal of the holding device from the undercarriage).In one possible embodiment of the method, it is provided that the luffing cylinder is always connected to a hydraulic system of the mobile crane and the luffing cylinder is extended via the hydraulic system.In a further possible embodiment, it is provided that the boom is first placed on a boom receptacle of the undercarriage, whereby the connection between the connecting means and the boom is relieved. This now enables a simpler release of the connection between the connecting means of the luffing cylinder and the boom.In a further possible embodiment, it is provided that the connecting means is connected to the receiving means in a rotationally fixed manner, so that a piston rod of the luffing cylinder does not rotate relative to a cylinder housing of the luffing cylinder during extension about its longitudinal axis.Further features, details and advantages of the invention are evident from the exemplary embodiments explained below with reference to the figures. The following are shown: FIG. 1 : a side view of the mobile crane according to the invention according to an exemplary embodiment; FIG. 2 : a perspective view of the holding device according to an exemplary embodiment; FIGS. 3 a- c : Side views of the boom, a luffing cylinder and the holding device of an exemplary embodiment of the mobile crane according to the invention in different positions during the transfer into the transport state; and FIGS. 4 a- b : perspective views of the luffing cylinders and of the holding device in different positions during the transfer into the transport state.FIG. 1 shows a side view of an exemplary embodiment of the mobile crane 1 according to the invention, which comprises a undercarriage 2 with a plurality of wheel axles, an undercarriage 3 mounted on the undercarriage 2 such that it can rotate about a vertical axis of rotation 32, and a boom 4 in the form of a telescopic boom mounted on the undercarriage 3 such that it can be tilted up and down about a horizontal luffing axis. The undercarriage 2 can have an undercarriage driver's cabin 7. The rotatable mounting of the superstructure 3 on the undercarriage 2 takes place in particular via a swivel ring.Two luffing cylinders 5 are used for luffing the boom 4, which are connected in an articulated manner to the superstructure 3 and in an articulated manner to the boom 4 via connecting means 6. By extending the piston rods of the luffing cylinders 5, the boom 4 is pivoted open. In the case of smaller mobile cranes, alternatively a single luffing cylinder 5 could be used, which is arranged centrally under the jib 4.The luffing cylinders 5 can be articulated on an articulation section of the telescopic jib 4. Preferably, the cylinder housings of the luffing cylinders 5 are articulated on the superstructure 3, while their piston rods 4 have at their free ends the connecting means 6, via which they are articulated on the boom 4 about horizontal pivot axes in the working operation.FIG. 1 shows the mobile crane 1 in a state in which the jib 4 is completely telescoping and is deposited on a jib storage 9 arranged on the undercarriage 2. As can likewise be seen in FIG. 1, the axis of rotation 32 of the superstructure 3 or the slewing ring is located in a rear region of the mobile crane 1. if the mobile crane 1 were now moving on public roads in this state, an excessively high load on the rear wheel axles could result, such that the predefined maximum axle loads are exceeded. In order to displace the center of gravity further forward (i.e. in the direction of the vehicle front or undercarriage driver's cabin 7) in a transport state for the road travel, the holding device 10 according to the invention is provided, which is not depicted in FIG. 1.An exemplary embodiment of the holding device 10 is illustrated in a perspective view in FIG. 2. The holding device 10 comprises a carrier plate 14 with an adjusting device which in the exemplary embodiment shown comprises four rollers 20 (alternatively, however, could comprise more or fewer rollers or another movement mechanism such as, for example, slide bearings). By means of the rollers 20, the holding device 10 rests on a part of the upper side of the undercarriage 2, which part is referred to as an adjusting surface 8, and can move thereon without hindrance (cf. FIGS. 4 a- b ). The holding device 10 preferably rolls directly on the undercarriage 2.The holding device 10 comprises a carrier 16 which is firmly connected to the carrier plate 14 and which, in the transport state, preferably extends transversely to the undercarriage longitudinal axis 30 (this is drawn in FIG. 4 b). At the ends of the carrier 16 there are receiving means 12 which are designed such that the connecting means 6 of the luffing cylinders 5 can be detachably fastened to the receiving means 12. For this purpose, the connecting means 6 of the luffing cylinders 5 are released from the corresponding articulation points on the boom 4 (in particular in a state deposited on the boom support 9, since this connection is relieved in this state), and the luffing cylinders 5 are lowered, wherein the luffing cylinders 5, which are still articulated on the superstructure 3, pivot downward about their pivot axes. This can be done, for example, by means of an auxiliary crane or an assembly device (e.g. a device known from DE 10 2020 106 899 A1).The holding device 10 is positioned on the undercarriage 2 or on the adjusting surface 8 such that by pivoting down the luffing cylinders 5, the connecting means 6 thereof (in the retracted state of the luffing cylinders 5) can be positioned correctly on the receiving means 12. The connecting means 6 are then fastened to the receiving means 12 so that the luffing cylinders 5 are now supported on the undercarriage 2 via the holding device 10.The luffing cylinders 5 remain connected to the hydraulic system of the mobile crane 1 during the entire process and are now extended. This operation is illustrated in FIGS. 3 a- c, which show a part of the boom 4, one of the luffing cylinders 5 and the holding device 10 from the side. The undercarriage 2 is only shown roughly schematically. Large parts of the superstructure 3 are omitted for the sake of clarity.FIG. 3 ashows the luffing cylinders 5 in a state connected to the boom 4. In FIG. 3 b, the luffing cylinder 5 has been lowered and connected to the receiving means 12 of the holding device 10. By extending the luffing cylinder 5, the holding device 10 is moved forwards along the longitudinal axis 30 of the undercarriage in the direction of the vehicle front, wherein the holding device 10 preferably rolls directly on the adjusting surface 8 via the rollers 20 thereof. Alternatively, a guide mechanism could be provided, which could comprise, for example, guide rails for the rollers 20 or alternatively for slide bearings.FIGS. 4 a- b show a perspective view of this process, but without boom 4, wherein in FIG. 4 a the luffing cylinders 5 are mounted on the holding device 10 and retracted and in FIG. 4 b are extended. The position of FIG. 4 b corresponds to the transport state.By extending the luffing cylinders 5, the center of gravity of the mobile crane 1 is displaced forwards. This is due on the one hand to the greater length of the luffing cylinders 5 (displacement of the centers of gravity of the luffing cylinders 5) and on the other hand to the fact that in the extended state the piston chambers of the luffing cylinders 5 are filled with hydraulic oil, since these have a greater volume than the annular chambers. In addition, the hydraulic tank of the hydraulic system is generally arranged far behind the superstructure 3, i.e. on the side of the axis of rotation 32 opposite the luffing cylinders 5. In the transport state, the mobile crane 1 has a better load distribution, i.e. a load distribution distributed more uniformly over the wheel axles, so that the road transport can take place in this position. In this case, the jib 4 can either remain on the superstructure 3 or it can be dismantled and transported separately.The connecting means 6 of the luffing cylinders 5 are preferably designed as brackets (or fingers) with a bolt receptacle. The receiving means 12 of the holding device 10 can accordingly comprise a bolt which can be mounted in bolt receptacles of the receiving means 12 and can be pushed through the bolt receptacle of the respective connecting means 6.It is likewise conceivable for the receiving means 12 to each comprise a bearing body 18 which is adapted to the dimensions of the bolt receptacles of the connecting means 6. These bearing bodies 18 form in particular cylindrical compensating bodies which do not have to be designed for the high forces which are transmitted during working operation at the connections between boom 4 and connecting means 6. An example of such bearing bodies 18 is illustrated in FIG. 2. Alternatively, normal pin connections could be used.In the exemplary embodiment of FIG. 2, it can furthermore be provided that the bearing bodies 18 are rotatably mounted in receptacles 13 which are formed in lateral fork plates of the receptacle means 12. The bearing bodies 18 can be mounted on the receiving means 12 by means of smaller bolts, which are correspondingly secured in the receiving means 13. By pulling the bolts, the bearing bodies 18 can be removed and subsequently removed from the bolt receptacles of the connecting means 6 of the luffing cylinders 5.For easier insertion of the bearing bodies 18 inserted into the bolt receptacles of the connecting means 6 of the luffing cylinders 5 during assembly on the holding device 10, the receiving means 12 can have insertion aids. In the embodiment of FIG. 2, the lateral fork plates of the receiving means 12 can have corresponding widened insertion sections 15 at their upper ends.The exemplary embodiment of FIG. 2 is designed for an embodiment of the mobile crane 1 with two luffing cylinders 5. In this case, the rigid carrier 16 functions as a cross member which rigidly connects the two receiving means 12 to one another and to the carrier plate 14.In an embodiment with only one luffing cylinder 5, correspondingly only one receiving means 12 is arranged on the carrier 16. This can be arranged centrally on the carrier 16 or on the carrier plate 14. Alternatively, the receiving means 12 could be arranged directly on the carrier plate 14 without carrier 16.The receiving means 12 (in the embodiment of FIG. 2, the bearing bodies 18) are designed such that the piston rods of the luffing cylinders 5 cannot rotate about their longitudinal axes during extension and retraction. Thus, a controlled retraction and extension of the luffing cylinders 5 takes place via the holding device 10.Stop elements 22 can be formed or arranged on the carrier 16 (cf. FIG. 2 ) in order to be able to lift and move the holding device 10 via a hoist. Alternatively, these could be arranged on the carrier plate 14.List of reference numbers:1 Mobile crane 2 undercarriage 3 superstructure 4 boom (telescopic boom) 5 luffing cylinder 6 connecting means 7 undercarriage driver's cabin 8 adjusting surface 9 boom receptacle 10 holding device 12 receiving means 13 receptacle 14 carrier plate 15 insertion section 16 carrier (cross member) 18 bearing body 20 rollers 22 stop element 30 undercarriage longitudinal axis 32 axis of rotation

Claims

Mobile crane (1) comprising a undercarriage (2) with wheel chassis, an undercarriage (3) rotatably mounted on the undercarriage (2) with a boom (4) pivotably mounted about a horizontal luffing axis, in particular a telescopic boom, and at least one hydraulic luffing cylinder (5) for swinging up and down the boom (4), which is pivotably mounted on the undercarriage (3) about a horizontal pivot axis and is connected in an articulated manner to the boom (4) via a connecting means (6), with a holding device (10) arranged on the undercarriage (2) for storing the luffing cylinder (5) in a transport state for road travel, which comprises a receiving means (12), characterized in that the connecting means (6) of the luffing cylinder (5) can be detachably connected to the receiving means (12), and in that the holding device (10) comprises an adjusting device, by means of which the holding device (10) is movable along a longitudinal direction (30) of the undercarriage by retracting and extending the accommodated luffing cylinder (5) relative to the undercarriage (2).Mobile crane (1) according to claim 1, wherein the undercarriage (2) comprises a boom receptacle (9) on which the boom (4) can be placed for road transport, wherein the undercarriage (2) preferably has an adjusting surface (8) on an upper side (3) below the boom (4) placed on the boom receptacle (9), along which the holding device (10) moves when the luffing cylinder (5) received in the holding device (10) is moved in or out.Mobile crane (1) according to claim 2, wherein at least one guide device is arranged on the adjustment surface (8), along which the holding device (10) is mounted so as to be movable, in particular displaceable or movable, via the adjustment device, wherein the guide device preferably extends along the longitudinal direction (30) of the undercarriage.Mobile crane (1) according to one of the preceding claims, wherein the adjusting device comprises rollers (20), via which the holding device (10) can be moved on an upper side of the undercarriage (2), in particular on an adjusting surface (8) formed on the upper side, wherein preferably the rollers (20) roll directly on the upper side of the undercarriage (2) or are mounted in guide rails running along the upper side of the undercarriage (2).Mobile crane (1) according to one of claims 1 to 3, wherein the adjusting device comprises slide bearings, via which the holding device (10) can be displaced on an upper side of the undercarriage (2), in particular on an adjusting surface (8) formed on the upper side, wherein preferably the slide bearings bear directly on the upper side of the undercarriage (2) or are slidingly mounted on guide devices, in particular slide rails, running along the upper side of the undercarriage (2).Mobile crane (1) according to one of the preceding claims, wherein the holding device (10) does not comprise a drive for moving the holding device (10) along the undercarriage longitudinal direction (30).Mobile crane (1) according to one of the preceding claims, wherein the connecting means (6) of the luffing cylinder (5) comprises a bolt receptacle, wherein preferably the receptacle means (12) comprises a bolt or bearing body (18) which can be received in the bolt receptacle of the luffing cylinder and is mounted on the receptacle means (12) in a rotationally fixed manner, in particular with respect to a luffing cylinder longitudinal axis.Mobile crane (1) according to one of the preceding claims, wherein the luffing cylinder (5) comprises a cylinder housing and a piston rod and the receiving means (12) is designed such that, when the luffing cylinder (5) received in the holding device (10) is extended, a rotation of the piston rod about its longitudinal axis relative to the cylinder housing is blocked.Mobile crane (1) according to one of the preceding claims, wherein the holding device (10) comprises a carrier plate (14), on which the adjusting device is arranged, and an in particular rigid carrier (16), which is connected to the carrier plate (14) and on which the receiving means (12) is arranged.Mobile crane (1) according to one of the preceding claims, comprising two luffing cylinders (5) for swinging up and down the boom, wherein the holding device (10) comprises two receiving means (12) for releasable connection to the connecting means (6) of a luffing cylinder (5) each, wherein the holding device (10) preferably comprises a carrier plate (14) with the adjusting device and an in particular rigid carrier (16) connected to the carrier plate (14), on which carrier the receiving means (12) are arranged, wherein the receiving means (12) are preferably arranged laterally next to the carrier plate (14).Mobile crane (1) according to one of the preceding claims, comprising a hydraulic circuit connected to the luffing cylinder (5) and having a hydraulic tank which is preferably arranged in a rear region of the superstructure (3).Method for moving a mobile crane (1) according to one of Claims 1 to 11 into a transport state, comprising the steps of: - releasing the luffing cylinder (5) at its connecting means (6) from the boom (4), wherein the luffing cylinder (5) remains connected to the superstructure (3) at its pivot axis, - lowering the luffing cylinder (5) to the receiving means (12) of the holding device (10), - connecting the connecting means (6) and the receiving means (12), - extending the luffing cylinder (5), wherein the holding device (10) moves along the longitudinal axis (30) of the undercarriage relative to the undercarriage (2) via its adjusting device.Method according to claim 12, wherein the luffing cylinder (5) is always connected to a hydraulic system of the mobile crane (1) and the luffing cylinder (5) is extended via the hydraulic system.Method according to claim 12 or 13, wherein the boom (4) is placed on a boom receptacle (9) of the undercarriage (2), whereby the connection between the connecting means (6) and the boom (4) is relieved, and subsequently the connection at the connecting means (6) to the boom (4) is released.Method according to one of Claims 12 to 14, wherein the connecting means (6) is connected to the receiving means (12) in a rotationally fixed manner, such that a piston rod of the luffing cylinder (5) does not rotate about its longitudinal axis relative to a cylinder housing of the luffing cylinder (5) during deployment.

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