JIB SYSTEM FOR A VEHICLE CRANE COMPRISING A BRACING APPARATUS AND METHOD FOR RIGGING AND DE-RIGGING A BRACING APPARATUS OF A VEHICLE CRANE

Abstract

A jib system for a vehicle crane having a telescopic jib and a bracing apparatus that can be coupled to the jib by its base frame, where the jib has a roller head and a lifting cable that is deflected via the roller head. Only minor structural measures and preparations are required for automatically rigging and de-rigging the vehicle crane, including by providing at least one transfer rocker that can be integrated in an articulated manner between the jib and the bracing apparatus. By the pivotable support of the transfer rocker on the jib, the base frame configured for coupling to the lifting cable can be displaced by a change in the length of the lifting cable that is effected in the coupled state on a circular path around its roller head from a set-down position of the bracing apparatus to a set-up position of the bracing apparatus and back.

Claims

1. A jib system of a vehicle crane, said jib system comprising: a telescopic jib having a roller head and a lifting cable that is deflected via the roller head; and a bracing apparatus having a base frame, wherein the bracing apparatus is configured to be coupled to the jib by the base frame with the base frame configured for coupling to the lifting cable; wherein at least one transfer rocker is provided between the jib and the bracing apparatus in an articulated manner, and wherein via the pivotable support of the at least one transfer rocker on the jib the base frame can be displaced when the base frame is in a coupled state with the lifting cable by a change in the length of the lifting cable on a circular path around its roller head from a set-down position of the bracing apparatus to a set-up position of the bracing apparatus and back.

2. The jib system as claimed in claim 1, wherein on the roller head or in the region of the roller head at least one first fastening point is provided that can be coupled or is coupled to a first end region of the at least one transfer rocker.

3. The jib system as claimed in claim 2, wherein the at least one first fastening point comprises two opposite first fastening points that can be coupled or are coupled to the first end region of the at least one transfer rocker.

4. The jib system as claimed in claim 1, wherein on the base frame of the bracing apparatus at least one second fastening point is provided that can be coupled or is coupled to a second end region of the transfer rocker.

5. The jib system as claimed in claim 4, wherein the at least one second fastening point comprises two fastening points that can be coupled or are coupled to the second end region of the transfer rocker.

6. The jib system as claimed in claim 1, wherein at least one linear drive having a first end and a second end is provided that is connected or is connectable to the roller head via its first end, wherein the at least one transfer rocker is supported or is supportable at least indirectly on the second end of the linear drive opposite the first end.

7. The jib system as claimed in claim 6, wherein the at least one transfer rocker is supported or is supportable via a lever connected thereto in a bending-resistant manner.

8. The jib system as claimed in claim 1, wherein the at least one transfer rocker extends between a first end region and a second end region of the at least one transfer rocker and comprises a linear drive having a first end and a second end and further comprises a lever that is connected in an articulated manner to the first end region of the at least one transfer rocker, wherein the lever includes a free end portion remote from the first end region of the transfer rocker, and wherein at the free end portion an attachment part is arranged that is configured for support on the roller head, and wherein the linear drive is connected in an articulated manner via its first end to the lever in the region of its free end portion and is connected in an articulated manner via its second end opposite the first end to a central portion of the transfer rocker.

9. The jib system as claimed in claim 1, wherein at least one tensile element is provided that is configured for at least temporarily connecting the bracing apparatus to the jib, and wherein the bracing apparatus comprises two arms that are connected in an articulated manner to the base frame and that each have a connecting point that can be connected or is connected to the tensile element.

10. The jib system of claim 9, wherein the jib system is equipped on a vehicle crane, and further comprising a transport unit configured to transport the bracing apparatus of the jib system, and wherein the jib system, the vehicle crane and the transport unit comprise a vehicle crane system.

11. The jib system of claim 1, wherein the jib system is equipped on a vehicle crane.

12. A method for transferring a bracing apparatus from a transport unit onto a jib of a vehicle crane having a jib system, comprising the steps of: providing the transport unit having the bracing apparatus received thereon in the region of the vehicle crane such that the bracing apparatus is arranged at least in regions below a front portion of the jib; coupling at least one transfer rocker and at least one tensile element in each case to the bracing apparatus and the jib; coupling a lifting cable of the vehicle crane that is deflected on a roller head of the jib to a base frame of the bracing apparatus; displacing the bracing apparatus attached to the jib from a set-down position in the direction of a set-up position by retracting the lifting cable coupled to the base frame such that, in terms of an oscillating movement of the entire bracing apparatus attached to the jib via the tensile element, its base frame that is supported on the jib by the at least one transfer rocker is rotated on a circular path around the roller head; further retracting the lifting cable coupled to the base frame until an attachment part of the transfer rocker is supported on the roller head or a linear drive connected to the roller head, thus blocking the base frame from being able to rotate further on the circular path; changing the length of the linear drive that extends at least indirectly between the attachment part and the transfer rocker or the roller head such that an otherwise unbraked further pivot movement of the transfer rocker is then effected during the rotation of the base frame on the circular path on passing beyond its top dead center in dependence upon the change in the length of the linear drive; further changing the length of the linear drive in parallel with or without further retracting the lifting cable coupled to the base frame until the base frame of the bracing apparatus is fully placed on the jib; fixing the base frame of the bracing apparatus to a fastening region of the jib; and decoupling at least the transfer rocker from the bracing apparatus before, during or after fixing the base frame of the bracing apparatus to the fastening region of the jib.

13. The method as claimed in claim 12, wherein said further changing the length of the linear drive comprises further changing the length of the linear drive until the base frame of the bracing apparatus is placed on the jib in the set-up position.

14. The method as claimed in claim 12, wherein said fixing the base frame of the bracing apparatus to a fastening region of the jib comprises fixing the base frame of the bracing apparatus to a fastening region of the jib via at least one releasable connection.

15. The method as claimed in claim 12, wherein prior to coupling the jib to the bracing device, the jib is luffed down if required in the direction of the bracing device received on the transport unit.

16. The method as claimed in claim 12, wherein prior to integrating the at least one transfer rocker between the bracing apparatus and the jib, the bracing apparatus is coupled to the jib if required via at least two mutually spaced apart tensile elements, and wherein the bracing apparatus is oriented relative to the jib via at least partially raising the bracing apparatus from the transport unit by luffing up the jib.

17. The method as claimed in claim 12, wherein the bracing apparatus, prior to commencing its displacement from the set-down position to the set-up position, is raised at least partially from the transport unit by luffing-up the jib.

18. The method as claimed in claim 12, further comprising telescoping the jib in and/or telescoping the jib out, if required, before, during or after the displacement of the linear drive until the base frame of the bracing apparatus configured for coupling to the fastening region of the jib is located in the designated position relative to the fastening region.

19. A method for transferring a bracing apparatus from a jib of a vehicle crane comprising a jib system onto a transport unit in a vehicle crane system, comprising the steps of: coupling at least one transfer rocker and at least one tensile element in each case to the bracing apparatus and/or the jib; releasing a base frame of the bracing apparatus from a fastening region of the jib before, during or after coupling of the bracing device to the jib; commencing the displacement of the bracing apparatus placed on the jib from a set-up position in the direction of a set-down position by changing the length of a linear drive that extends at least indirectly between an attachment part and the transfer rocker or a roller head, until the transfer rocker is pivoted beyond its top dead centre; coupling a lifting cable of the vehicle crane deflected at the roller head of the jib to the base frame before, during or after pivoting of the transfer rocker by changing the length of the linear drive; slackening the lifting cable coupled to the base frame by removing the support of the attachment part of the transfer rocker at the roller head such that, in terms of an oscillating movement of the entire bracing apparatus attached to the jib via the tensile element, the base frame that is supported on the jib by the at least one transfer rocker is rotated on a circular path around the roller head; providing the transport unit in the region of the vehicle crane before, during or after the aforementioned measures such that it is arranged at least in regions below the bracing apparatus and/or a front portion of the jib; further slackening the lifting cable coupled to the base frame and/or luffing-down the jib until the bracing apparatus is placed at least partially on the transport unit; and decoupling the bracing apparatus from the jib.

20. The method as claimed in claim 19, wherein the jib is luffed down if required before, during or after slackening of the lifting cable coupled to the base frame until the bracing apparatus is placed at least partially on the transport unit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 shows a side view of a vehicle crane system in accordance with the invention consisting of a vehicle crane and a transport unit;

[0035] FIG. 2 shows the vehicle crane system of FIG. 1, wherein the transport unit has driven up to the vehicle crane;

[0036] FIG. 3 shows a top view of the vehicle crane system according to FIG. 2;

[0037] FIG. 4 shows a further top view according to FIG. 3, wherein a bracing apparatus on the transport unit is oriented with a jib of the vehicle crane;

[0038] FIG. 5 shows a detail of a side view of the vehicle crane according to FIG. 1 from the region of the jib and the bracing apparatus to be attached in a first position of the bracing apparatus with respect to the jib;

[0039] FIG. 6 shows the detail according to FIG. 5 in a second position of the bracing apparatus with respect to the jib; and

[0040] FIG. 7 shows the detail according to FIG. 5 in a third position of the bracing apparatus with respect to the jib.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0041] FIG. 1 shows a side view of a vehicle crane system 1 in accordance with the invention which is located on a ground U and which comprises a multi-axle vehicle crane 2 or mobile crane which can be driven on roads, and a transport unit 3. The vehicle crane 2 is equipped with a jib system 4 in accordance with the invention which includes a jib 5, which is arranged on the vehicle crane 2, and a bracing apparatus 6. In the situation shown here relating to a procedure of attaching the bracing apparatus 6 to the jib 5, the bracing apparatus 6 still lies on a storage surface 3a of the transport unit 3, by means of which the bracing apparatus 6 has been transported separately from the vehicle crane 1 to the place of usage of the vehicle crane 1. In this case, the transport unit 3 is designed in a known manner as a trailer truck comprising a towing vehicle and a semi-trailer. In a corresponding manner, the storage surface 3a for the bracing apparatus 6 lies on the semi-trailer. The vehicle crane 2 typically has a lower carriage 2a, on which a superstructure 2b carrying the jib 5 is arranged. The superstructure 2b can be pivoted relative to the lower carriage 3 about an axis of rotation Z1 which extends in parallel with an upwards direction Z. The jib 5 which extends with its longitudinal axis X1 substantially in parallel with a longitudinal direction X is articulated to the superstructure 2b so as to be correspondingly luffable via a horizontal pivot axis Y1 (as indicated by the curved double arrow). In the example shown here, the lower carriage 2a has a wheeled running gear unit which has a total of seven axles each having at least two rubber-tyred wheels which are rotatably mounted thereon and are spaced apart from one another in parallel with a vertical direction Y. The jib 5 which in this case is telescoped out only slightly has a basic box 5a which is arranged on the superstructure 2b and has inner boxes 5b which are arranged therein preferably so as to be hydraulically longitudinally displaceable in relation to the longitudinal axis X1 of the jib 5, among the inner boxes the innermost inner box 5b carries, at its upper end, a roller head 5c and is slightly extended.

[0042] It can also be seen in FIG. 1 that the superstructure 2b of the vehicle crane 2 is pivoted about approximately 180° rearwards from a position directed forwards for the operation of driving the vehicle crane 2 on roads and therefore the jib 5 protrudes rearwards far beyond the lower carriage 2a. In a corresponding manner, it is indicated in FIG. 1 that rear supports of the vehicle crane 2 which are not designated in greater detail by a reference numeral have been extended for the purpose of levelling and stabilising the vehicle crane 2.

[0043] FIG. 2 shows the vehicle crane system 1 of FIG. 1 in a position in which the bracing apparatus 6 is transferred from the transport unit 3 by means of the main jib 5, wherein for the upcoming procedure of attaching the bracing apparatus 6 to the main jib 5 the main jib 5 has been luffed up slightly about the pivot axis Y1 and subsequently the transport unit 3 has been driven rearwards towards the rear end of the vehicle crane 2. The driving movement of the transport unit 3 is indicated by a white arrow. The main jib 5 has been luffed up to such an extent that after the transport unit 3 has been driven towards the vehicle crane 2 the roller head 5c of the jib 5 is located above the bracing apparatus 6. By reason of the ascending orientation of the jib 5, the basic box 5a of the jib 5 is introduced partially and increasingly into the bracing apparatus 6 from above as seen in the longitudinal direction X1 of said jib and in the direction of the superstructure 2b. In a corresponding manner, the transport unit 3 is positioned in this transfer position with respect to the vehicle crane 2 such that the bracing apparatus 6 is arranged for the most part below a front portion of the jib 5.

[0044] FIG. 3 shows a top view of the vehicle crane system 1 of FIG. 2. It can be seen that the bracing apparatus 6 is not oriented in an optimum manner with respect to the jib 5. In contrast to FIG. 2, the jib 5 is no longer located between arms 6b, 6c of the bracing apparatus 6 but instead is already located slightly above the left arm 6b of the bracing apparatus 6. Therefore, the jib 5 is luffed up further than is illustrated in FIG. 2, in order to avoid a collision with the arm 6b. An optimum orientation would be present if the longitudinal axis X1 of the jib 5 was aligned with a central longitudinal axis, not illustrated in greater detail, of the bracing apparatus 6. However, in the present case there is an angular offset between the longitudinal axis X1 and the longitudinal axis of the bracing apparatus 6. In addition to this angular offset, a lateral offset and/or a vertical offset could also be present or could also additionally be present. These different types of offset which can occur are attributed to the orientation of the transport unit 3 as it drives rearwards towards the vehicle crane 2, the orientation of the bracing apparatus 6 on the storage surface 3a of the transport unit 3, and the orientation of the storage surface 3a of the transport unit with respect to the vehicle crane 2 by reason of non-horizontal progressions of the ground U. In the transfer position shown in FIG. 3, the bracing apparatus 6 is oriented slightly obliquely with respect to the longitudinal axis X1 of the jib 5; however, the vehicle crane 2 and the transport unit 3 are positioned on an even ground U.

[0045] Moreover, FIG. 3 shows the basic structure of the bracing apparatus 6 which has a base frame 6a and two arms 6b, 6c which are connected in an articulated manner to the base frame 6a. It can be seen in the top view that the bracing apparatus 6 is thus configured in a substantially U-shaped manner, and the arms 6b, 6c adjoin the lateral ends of the base frame 6a. The base frame 6a which connects the two arms 6b, 6c is located in the transfer position, as seen in the direction of the longitudinal axis X1 of the jib 5, at a sufficient spaced interval in advance of the roller head 5c such that, after the bracing apparatus 6 has been oriented with respect to the jib 5, the jib 5 can be introduced between the two arms 6b, 6c and past the base frame 6a into the bracing apparatus 6.

[0046] In relation to the orientation of the bracing apparatus 6 with respect to the jib 5, it can be seen in FIG. 3 that the bracing apparatus 6 is oriented obliquely with respect to the jib 5 such that the free end of the arm 6b is located below the basic box 5a of the trailer 5. In a corresponding manner, the jib 5 must be luffed up in the preceding step until its basic box 5a is located completely above the bracing apparatus 6 which at this point in time is still resting on the storage surface 3a of the transport unit 3. Only when the bracing apparatus 6 is oriented more effectively with respect to the jib 5, can the jib 5 be luffed up to a lesser extent because the jib 5 can then be moved even partially between the arms 6b, 6c as the transport unit 3 is driven rearwards towards the vehicle crane 2.

[0047] In order to orient the bracing apparatus 6 relative to the jib 5, the bracing apparatus 6 is connected to the jib 5 via a total of four tensile elements 7a to 7d indicated in this case only by black dots. The tensile elements 7a to 7d are designed in a typical manner as chains, cables or belts. As seen in the top view, the four tensile elements 7a to 7d are arranged in the corners of a notional rectangle, the longitudinal extension of which runs in the direction of the longitudinal axis X1. In this case, the tensile elements 7a, 7d facing the vehicle crane 2 connect the basic box 5a in each case to a free end of the arms 6b, 6c and the tensile elements 7b, 7c remote from the vehicle crane 2 connect the roller head 5c in the region of an upper roller head axis to the end of the arms 6b, 6c facing the base frame 6a. After coupling via the tensile elements 7a to 7d, the jib 5 is luffed up, whereby the bracing apparatus 6 is raised from the storage surface 3a of the transport unit 3 and is thus oriented automatically relative to the jib 5 in a freely suspended manner by utilising the gravitational force. Subsequently, the thus oriented bracing apparatus 6 is then set down on the storage surface 3a of the transport unit 3 by luffing the jib 5 down. In this respect, it can be seen in FIG. 2 that the bracing apparatus 6 when in the set-down state rests on the storage surface 3a of the transport unit 3 substantially via four points. In this respect, a support 6d is arranged in each case in the region of the centre of each arm 6b, 6c and can be formed in a v-shape or as a vertical post. The fastening winches 6e of the bracing apparatus 6 which are arranged in the region of the ends of the arms 6b, 6c facing the base frame 6a and protrude downwards are used as further supports. In the case of other designs of the bracing apparatuses 6, corresponding supports could also be provided instead of the fastening winches 6e or could be provided on the fastening winches 6e. In conjunction with the setting down of the bracing apparatus 6 on the support surface 3a of the transport unit 3 after automatic orientation has been effected, it may be necessary that the length of the supports 6d or of corresponding supports on the fastening winches 6e has to be adapted in length in order to maintain at least the achieved horizontal orientation of the bracing apparatus 6 with respect to the jib 5. This is necessary particularly if the loading surface 3a is not oriented horizontally when the vehicle crane 3 is supported horizontally.

[0048] It is obvious that this step of orienting can be omitted if the bracing apparatus 6 is already oriented with respect to the jib 5 on the storage surface 3a of the transport unit 3 by merely driving the transport unit 3 towards the vehicle crane 2.

[0049] FIG. 4 shows the top view according to FIG. 3 but after the automatic orientation of the bracing apparatus 6 relative to the jib 5 and the setting down of the oriented bracing apparatus 6 on the storage surface 3a of the transport unit 3. Subsequently, the tensile elements 7b, 7c which are located in the region of the base frame 6a of the bracing apparatus 6 are removed. The remaining two tensile elements 7a, 7d in the region of the arms 6b, 6c remain on the jib 5 and are lengthened or are replaced by other, preferably longer, tensile elements 7a, 7d which are adapted in terms of their length to the further steps of the attachment procedure. If required, the jib 5 is luffed down further in the direction of the bracing apparatus 6 so that it adopts a position relative to the bracing apparatus 6 which is expedient for the next measures.

[0050] FIG. 5 shows a detail of a side view of the vehicle crane 2 according to FIG. 1 from the region of the jib 5 and the bracing apparatus 6 to be attached in a first position of the bracing apparatus 6 with respect to the jib 5 which is defined as the set-down position A1. In this set-down position A1, the bracing apparatus 6 is already suspended from the jib 5, has previously already been raised slightly from the storage surface 3a of the transport unit 3 by the jib 5 and the transport unit 3 has been driven away under the jib 5. The bracing apparatus 6 is suspended from the jib 5 via an illustrated front tensile element 7a, a concealed rear tensile element 7d in parallel therewith, a front, rod-shaped transfer rocker 8 and a concealed rear transfer rocker in parallel therewith. In addition, a lifting cable 9 is guided along the jib 5 via an upper deflection roller 13 of the roller head 5c to the front central end of the base frame 6a as seen in the longitudinal axis X1 of the jib 5, and at this location is fastened to the base frame 6a at a fourth fastening point S4. The lifting cable 9 is illustrated only symbolically by a dot and dash line. Therefore, the bracing apparatus 6 is suspended from the jib 5 at five points in total.

[0051] In order to achieve this state, in addition to the lifting cable 9, prior to lifting the bracing apparatus 6 from the transport unit 3, the tensile elements 7a, 7d are each fastened in an articulated manner with their lower end to the lower end of the respective support 6d at a third fastening point S3 and are fastened in an articulated manner with their upper end at the top laterally to the basic box 5a of the jib 5 at a fifth fastening point S5. At this location, the tensile elements 7a, 7d are also already fastened when the bracing apparatus 6 is automatically oriented with respect to the jib 5. Also, a transfer rocker 8 is fastened in each case with its lower first end region 8a at a first fastening point S1 in the lower region of the roller head 5c and is fastened with its opposite upper second end region 8b at the front and laterally to the base frame 6a at a second fastening point S2. From the arrangement of the fifth fastening point S5 with respect to the third fastening point S3 and of the second fastening point S2 with respect to the first fastening point S1, it is apparent that the bracing apparatus 6 is not freely suspended from the jib 5 but instead is already pivoted to the left on a circular path via the lifting cable 9 and therefore is located outside possible dead centres in relation to the pivoting drive or attachment drive via the lifting cable 9. In a corresponding manner, the tensile elements 7a, 7d and the deflection rockers 8 are pivoted, in relation to a vertical, to the left about the fifth fastening point S5 or the second fastening point S2.

[0052] The fastening of the tensile elements 7a, 7d and the two transfer rockers 8 to the jib 5 or the bracing apparatus 6 is configured in each case to be pivotable at least about an axis which is horizontal and is oriented transversely with respect to the longitudinal axis X1 of the trailer 5. As seen in the top view according to FIG. 4, the tensile elements 7a, 7d and the two transfer rockers 8 extend in a lateral intermediate space between the jib 5 or its basic box 5a or roller head 5c and an inner side of the arms 6b, 6c. Moreover, provision is made that the transfer rockers 8 are oriented in relation to the driving lifting cable 9 outside their dead centre and forwards as seen in the direction of the longitudinal axis X1. The same applies to the tensile elements 7a, 7d in order thus to achieve defined movement kinematics of the bracing apparatus 6 with respect to the jib 5.

[0053] The tensioned lifting cable 9 and the tensile elements 7a, 7d which are tensile-loaded thereby and the two compression-loaded transfer rockers 8 ensure that the bracing apparatus 6 remains in the set-down position A1 illustrated in FIG. 5 even if the bracing apparatus 6 is raised from the storage surface 3a of the transport unit 3 by means of luffing the jib 5.

[0054] FIG. 6 shows the commencement of the displacement of the bracing apparatus 6 from its set-down position A1 in the direction of a set-up position A2 on the upper side of the jib 5. For this purpose, winding of the lifting cable 9 causes a corresponding tensile force to be applied to the bracing apparatus 6 such that the base frame 6a which is coupled to the lifting cable 9 and is supported by means of the two transfer rockers 8 on the jib 5 is rotated upwards around the roller head 5c on a circular path at a spaced interval and without any collisions (as indicated by the white arrow curved in the clockwise direction). The radius of said circular path is defined by the length of the transfer rockers 8 extending between the fastening points S1, S2. In this case, the bracing apparatus 6 which at the same time is attached to the jib 5 via the tensile elements 7a, 7d is displaced in terms of an oscillating movement relative to the jib 5 in the direction of the vehicle crane 2, which is composed of a rotational and at the same time translational movement sequence in which the bracing apparatus 6 is supported on the pivoting tensile elements 7a, 7d (as indicated by the white arrow curved in the anticlockwise direction). Since the height of the fourth fastening point S4 of the lifting cable 9 at the base frame 6A exceeds the height of the deflection roller 13 at the roller head 5c, the guidance via the deflection roller 13 is abandoned or is no longer required.

[0055] In order to avoid a situation where, after passing beyond a vertical orientation of the transfer rocker 8 in terms of a top dead centre and further tensile movement of the lifting cable 9, the bracing apparatus 6 comes to lie with its base frame 6a in an uncontrolled manner on the upper side of the basic box 5a, the tensile force of the lifting cable 9 is to be advantageously subjected to a counter force which acts upon the transfer rockers 8 and is less than the tensile force of the lifting cable 9. This counter force can be provided in the form of a spring or a hydraulic cylinder. The hydraulic cylinder has the advantage that it can also be used during the course of detaching the bracing apparatus 6 from the jib 5 in order to reach and pass beyond the aforementioned top dead centre in the opposite direction.

[0056] In the embodiment variant shown here purely by way of example, the transfer rocker 8, in the region of the first fastening point S1, is additionally connected in a bending-resistant manner to a lever 10 and is thus configured as an angle lever. An attachment part 11 is arranged at a free end of the lever 10. Furthermore, a linear drive 12 is laterally connected to the roller head 5c via its first end 12a and is oriented vertically when the jib 5 extends horizontally. Before or upon reaching a top dead centre of the second end region 8b of the transfer rocker 8—in this case approximately a vertical—the attachment part 11 of the lever 10 is supported on a second end 12b of the linear drive 12 opposite the first end 12a. At this moment, the ability of the base frame 6a to rotate further on the circular path around the roller head 5c is initially blocked and is dependent upon a change in the length of the linear drive 12.

[0057] FIG. 7 shows a further detail according to FIG. 5 in a third position of the bracing apparatus 6 with respect to the jib 5. In this third position, the base frame 6a of the bracing apparatus 6 is placed on the basic box 5a of the jib 5 and the bracing apparatus 6 has reached its set-up position A2 on the jib 5. For this purpose, the further rotation of the base frame 6a on the circular path about the roller head 5c was effected in that the linear drive 12 was retracted against the cable force of the lifting cable 9. The second end region 8b of the transfer rocker 8 which is loaded by means of the weight of the bracing apparatus 6 has thereby been lowered slowly towards the jib 5, wherein its first end region 8a has been continuously damped or braked in a controlled manner with respect to a free rotation about the fastening pint S1 at the roller head 5c via the lever 10 supported on the linear drive 12. Depending upon the configuration or procedure, a further retraction of the lifting cable 9 can be effected or omitted during this movement. Without the lifting cable 9, the attachment part 11 must be bolted beforehand to the second end 12b of the linear drive 12.

[0058] Finally, the bracing apparatus 6, in particular its base frame 6a, is then still to be fastened to the basic box 5a. This is typically effected by bolting a first connection plate 14a to the basic box 5a and a second connection plate 14b to the base frame 6a. Solely by reaching the set-up position A2, the base frame 6a is oriented with its connection plates 14a, of which only a front one is shown in FIG. 7 since the rear one in parallel therewith is concealed thereby, if necessary in the height direction with respect to the second connection plates 14b on the base frame 6a. The spaced interval between the first and second connection plates 14a, 14b which form a fastening region if the bracing apparatus 6 is located in the set-up position A2 can be adjusted over the length of the transfer rockers 8. In the present exemplified embodiment, the length of the transfer rockers 8 is selected to be slightly longer so that the first connection plates 14a are oriented as seen in the longitudinal axis X1 with respect to the second connection plates 14b in a slightly offset manner with respect to the superstructure 3. Basically, the length of the transfer rockers 8 can also be selected such that the two connection plates 14a, 14b are already aligned with one another when the set-up position A2 is reached. In the present case, the base frame 6a of the bracing apparatus 6 which is connected to the roller head 5c via the transfer rockers 8 will be displaced with its first connection plates 14a into the aligned position relative to the second connection plates 14b of the jib 5, in that the innermost inner box 5b with the roller head 5c is telescoped out accordingly. If, as a result, the first and second connection plates 14a, 14b of the fastening region are aligned with one another, the base frame 6a is fixed to the jib 5 via fastening means which are not shown in greater detail here. Subsequently, rigging cylinders 15 arranged in each case on the arms 6b, 6c in proximity to the base frame 6a are pivoted from a parking position to an operating position and are fastened to the lower sides of the basic box 5a at corresponding bearing points. By actuating the rigging cylinders 15, the arms 6b, 6c can be pivoted slightly upwards and therefore the tensile elements 7a, 7d can be relieved and removed. Then, the transfer rockers 8 are decoupled from the bracing apparatus 6 or its base frame 6a in order to permit the telescoping capability of the jib 5. The transfer rockers 8 remain on the roller head 5c in a parking position. Accordingly, the lifting cable is released from the fourth fastening point S4 and reeved at the roller head 5c for the normal crane operation of the vehicle crane 2.

[0059] In an alternative embodiment of the transfer rocker 8, provision is made to form the lever 10 not in a bending-resistant manner but instead to form said lever like the transfer rocker 8 in such a manner as to be pivotable about the first fastening point S1. Furthermore, the linear drive 12 is then connected via its first end 12a in an articulated manner to the lever 10 at the free end portion 10a thereof. The second end 12b of the linear drive 12 is connected in an articulated manner to a central portion 8c of the transfer rocker 8. In the case of this alternative, the lever 10 also pivots with its attachment part 11 during retraction of the lifting cable 9, which is coupled to the base frame 6a, as far as a stop on the roller head 5c. From this point in time, the otherwise unbraked further pivot movement of the transfer rocker 8, as it passes beyond its top dead centre, is likewise effected in dependence upon the change in the length of the linear drive 12 as also in the previously demonstrated variant.

[0060] The transfer of the bracing apparatus 6 from the jib 5 of the vehicle crane 2 onto the transfer unit 3, which extends quasi in the opposite direction, is effected in a correspondingly expedient reverse order of the individual measures, as already explained in greater detail in the description. In both variants, the displacement of the bracing apparatus 6 placed on the jib 5 from its set-up position A2 in the direction of the set-down position A1 commences by reducing the length of the linear drive 12 which is supported indirectly on the roller head 5c of the jib 5 via the contact part 11. In contrast, said transfer in the previously demonstrated embodiment variant is effected by increasing or reducing the length of the linear drive 12 connected to the roller head 5c. In both cases, the transfer rocker 8 is pivoted until its second end region 8b reaches the top dead centre. The movement sequence beyond this is based upon the slackening of the lifting cable 9 coupled to the base frame 6a of the bracing apparatus 6.

[0061] Changes and modifications in the specifically described embodiments can be carried out without departing from the principles of the present invention which is intended to be limited only by the scope of the appended claims, as interpreted according to the principles of patent law including the doctrine of equivalents.